Terminal, wireless communication method, and base station

Abstract

A terminal according to one aspect of the present disclosure has: a transmission unit that transmits a first message relating to an initial access procedure for a plurality of cells to at least one of the plurality of cells; and a control unit that controls reception of a second message corresponding to the first message and transmitted from at least one of the plurality of cells. According to the one aspect of the present disclosure, it is possible to properly perform communication by using a plurality of carriers / cells / bands.

Description

Terminal, wireless communication method and base station

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

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

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

[0004] 3GPP TS 36.300 V8.12.0 “Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Overall description; Stage 2 (Release 8)”, April 2010

[0005] In future wireless communication systems, it is being considered that a terminal (user terminal, User Equipment (UE)) will perform an initial access procedure for multiple carriers / cells.

[0006] However, the method of such an initial access procedure has not been sufficiently considered, and if this consideration is insufficient, there is a risk that the initial access procedure will not be carried out properly.

[0007] Therefore, one of the objects of the present disclosure is to provide a terminal, a wireless communication method, and a base station that can appropriately communicate using multiple carriers / cells / bands.

[0008] A terminal according to one aspect of the present disclosure has a transmitting unit that transmits a first message regarding an initial access procedure for a plurality of cells to at least one of the plurality of cells, and a control unit that controls reception of a second message transmitted from at least one of the plurality of cells in response to the first message.

[0009] According to one aspect of the present disclosure, communication can be performed appropriately using multiple carriers / cells / bands.

[0010] FIG. 1 is a diagram showing an example of an initial access procedure for multiple carriers / bands. FIG. 2 is a diagram showing an example of procedure A according to a first embodiment. FIG. 3 is a diagram showing an example of procedure B according to a second embodiment. FIG. 4 is a diagram showing an example of procedure C according to a third embodiment. FIG. 5 is a diagram showing an example of procedure D according to a fourth embodiment. FIG. 6 is a diagram showing an example of a schematic configuration of a wireless communication system according to an embodiment. FIG. 7 is a diagram showing an example of a configuration of a base station according to an embodiment. FIG. 8 is a diagram showing an example of a configuration of a user terminal according to an embodiment. FIG. 9 is a diagram showing an example of hardware configurations of a base station and a user terminal according to an embodiment. FIG. 10 is a diagram showing an example of a vehicle according to an embodiment.

[0011] (Initial Access Procedure) In the 5G NR initial access procedure, the UE (RRC_IDLE mode) receives the SS / PBCH block (SSB), transmits message (Msg.) 1 (PRACH / random access preamble / preamble), receives Msg. 2 (PDCCH, PDSCH including random access response (RAR)), transmits Msg. 3 (PUSCH scheduled by RAR UL grant), and receives Msg. 4 (PDCCH, PDSCH including UE contention resolution identity). After that, when an ACK for Msg. 4 is sent from the UE by the base station (network), an RRC connection is established (RRC_CONNECTED mode).

[0012] SSB reception includes PSS detection, SSS detection, PBCH-DMRS detection, and PBCH reception. PSS detection includes detecting part of the physical cell ID (PCI), detecting (synchronizing) OFDM symbol timing, and (coarse) frequency synchronization. SSS detection includes detecting the physical cell ID. PBCH-DMRS detection includes detecting (part of) the SSB index within a half radio frame (5 ms). PBCH reception includes detecting the system frame number (SFN) and radio frame timing (SSB index), receiving configuration information for receiving remaining minimum system information (RMSI, SIB1), and recognizing whether the UE can camp on that cell (carrier).

[0013] SSB has a bandwidth of 20 RBs and a time of 4 symbols. The transmission period of SSB can be set to {5, 10, 20, 40, 80, 160} ms. In a half frame, multiple symbol positions of SSB are defined based on the frequency range (FR1, FR2).

[0014] The PBCH has a payload of 56 bits. N repetitions of the PBCH are transmitted within a period of 80 ms, where N depends on the SSB transmission period.

[0015] The system information consists of the MIB, RMSI (SIB1), and other system information (OSI) carried by the PBCH. SIB1 contains information for RACH setup and RACH procedures. The time / frequency resource relationship between the SSB and the PDCCH monitoring resource for SIB1 is configured by the PBCH.

[0016] The PDSCH carrying SIB1 (SIB1 PDSCH) is transmitted periodically. The PDSCH is scheduled by Type 0-PDCCH. One SSB corresponds to one SIB1 PDSCH. One SIB1 PDSCH may or may not be repeated twice. SIB1 sets the public land mobile network (PLMN) ID. The PLMN ID may also be called the Mobile Network Operator (MNO) identifier.

[0017] The PLMN ID is a globally unique identifier used to identify an MNO.

[0018] The UE identifies the MNO to perform the network access operation based on specific parameters in the system information (e.g., SIB1) (e.g., PLMN identity information list (e.g., PLMN-IdentityInfoList) in the cell access related information (e.g., CellAccessRelatedInfo)).

[0019] A base station using beam correspondence transmits multiple SSBs using multiple beams (analog beams) for each SSB transmission period. The multiple SSBs may be referred to as SSB bursts. The multiple SSBs have multiple SSB indices. A UE that detects an SSB transmits a PRACH in the RACH occasion associated with that SSB index and receives an RAR in the RAR window.

[0020] (Analysis) In the above-described 5G NR initial access procedure, the UE performs initial access on only one of the camped / accessible carriers.

[0021] Furthermore, when communication is performed using multiple carriers, control procedures related to carrier aggregation (CA) / dual connectivity (DC) are required after RRC connection, which leads to an increase in signaling overhead / base station power consumption.

[0022] The introduction of initial access to multiple carriers is being considered for future wireless communication systems, but the specific methods for this introduction have not been fully explored.

[0023] For example, in order to enable initial access to multiple carriers / cells based on existing initial access procedures, it would be necessary to design a system in which synchronization signals (e.g., SSB) are transmitted in each carrier / cell, which would lead to increased power consumption by the base station.

[0024] Thus, if the initial access method for multiple carriers is not sufficiently considered, there is a risk that an appropriate initial access procedure will not be executed.

[0025] Therefore, the present inventors have conceived a method for solving this problem. According to one aspect of the present disclosure, communication can be performed using a wide range or multiple carriers / cells / bands required for communication, with fewer procedures or low latency procedures in the UE.

[0026] Hereinafter, embodiments according to the present disclosure will be described in detail with reference to the drawings. Wireless communication methods according to the embodiments may be applied independently or in combination.

[0027] (Various Reinterpretations) In the present disclosure, a word enclosed in "( )" in a sentence may indicate an explanation of the word immediately preceding it (for example, an explanation of spelling), a paraphrase, a specific example, a supplementary explanation, etc. Furthermore, in the present disclosure, a word enclosed in "[ ]" in a sentence may be interpreted including the word in the meaning of the entire sentence, or may be interpreted excluding (ignoring) the word in the meaning of the entire sentence. Note that "( )" and "[ ]" may also be used for purposes / meanings other than those mentioned above.

[0028] In the present disclosure, "A / B" and "at least one of A and B" may be interpreted interchangeably. Also, in the present disclosure, "A / B / C" may mean "at least one of A, B, and C."

[0029] In the present disclosure, terms such as notify, activate, deactivate, indicate (or indicate), select, configure, update, and determine may be read interchangeably. In the present disclosure, terms such as support, control, controllable, operate, and operate may be read interchangeably.

[0030] In the present disclosure, Radio Resource Control (RRC), RRC parameters, RRC messages, higher layer parameters, fields, information elements (IEs), settings, etc. may be interchangeable. In the present disclosure, Medium Access Control (MAC) control elements (CEs), update commands, activation / deactivation commands, etc. may be interchangeable.

[0031] In the present disclosure, the higher layer signaling may be, for example, any one of Radio Resource Control (RRC) signaling, Medium Access Control (MAC) signaling, broadcast information, other messages (e.g., messages from the core network such as positioning protocol (e.g., NR Positioning Protocol A (NRPPa) / LTE Positioning Protocol (LPP)) messages), or a combination thereof.

[0032] In the present disclosure, MAC signaling may use, for example, a MAC Control Element (MAC CE), a MAC Protocol Data Unit (PDU), etc. Broadcast information may be, for example, a Master Information Block (MIB), a System Information Block (SIB), Remaining Minimum System Information (RMSI), Other System Information (OSI), etc.

[0033] In the present disclosure, physical layer signaling may be, for example, Downlink Control Information (DCI), Uplink Control Information (UCI), and the like.

[0034] In the present disclosure, the terms carrier, band, cell, frequency, etc. may be read interchangeably.

[0035] In the present disclosure, a cell may refer to a cell or supercell whose configuration / physical range does not change (in a cell-free configuration), or may refer to a cell, subcell, or area whose configuration / physical range may change (in a cell-free configuration). Therefore, in the present disclosure, cell, supercell, subcell, area, etc. may be read as interchangeable terms.

[0036] In the present disclosure, Msg. 1, PRACH, random access preamble, preamble, signal related to procedure A, procedure A, first message, etc. may be read interchangeably.

[0037] In the present disclosure, Msg. 2, a PDCCH associated with the RAR, an RAR, a PDSCH including the RAR, a response to Msg. 1, a signal related to procedure B, procedure B, a second message, etc. may be read interchangeably.

[0038] In the present disclosure, Msg. 3, PUSCH scheduled by RAR UL grant, response to Msg. 2, signal related to procedure C, procedure C, third message, etc. may be read interchangeably.

[0039] In the present disclosure, Msg. 4, Msg. 4 PDCCH, PDSCH including UE contention resolution identity, response to Msg. 3, signaling related to procedure D, procedure D, fourth message, etc. may be read interchangeably.

[0040] In the present disclosure, system information, system information block (SIB), SIB1, SIB based on SIB1 (SIBx (x is an integer of 2 or more)), etc. may be read interchangeably.

[0041] (Wireless Communication Method) A UE may perform initial access procedures for multiple carriers / bands (simultaneously / in parallel).

[0042] The initial access procedure in the UE may include the following steps A to D: Step A: PRACH transmission on any carrier / band; Step B: RAR reception from any carrier / band (monitoring the PDCCH / search space / CORESET associated with the RAR); Step C: Msg. 3 transmission on any carrier / band; Step D: Msg. 4 reception from any carrier / band.

[0043] At least two of the above procedures A to D may be combined and defined as one procedure. For example, the UE may perform a procedure that combines procedures A and C, and then perform a procedure that combines procedures B and D (this procedure may be called a two-step initial access procedure).

[0044] Furthermore, the names of procedures in this disclosure are merely examples and are merely described for convenience.

[0045] For an initial access procedure for multiple carriers / bands, at least one of the transmission and reception of signals defined as the initial access procedure may be performed for multiple carriers / bands.

[0046] For example, the UE may perform at least some of the procedures (e.g., procedures after a specific procedure, procedures before a specific procedure, or only a specific procedure) for multiple carriers / bands.

[0047] The UE may perform at least one of the above procedures A to D (which may also be called procedure X) if and only if certain conditions are met (e.g., conditions for performing an initial access procedure for any carriers / bands).

[0048] Figure 1 shows an example of an initial access procedure for multiple carriers / bands. In the example shown in Figure 1, a UE performs initial access to at least carriers #1 to #3. In the table shown in Figure 1, the procedure to be performed is indicated by "Y".

[0049] In the example shown in FIG. 1, the UE performs procedure A for carriers #1 and #2, procedure B for carrier #2, procedure C for carriers #2 and #3, and procedure D for carrier #3.

[0050] In the present disclosure, performing procedure X (transmission / reception related to procedure X) simultaneously / concurrently may include at least one of the following: - Transmission / reception related to procedure X is performed in time resources (e.g., symbols / slots / subframes / radio frames) that partially / fully overlap. - At least a portion of transmission / reception related to procedure X (e.g., all / some / the immediately preceding N / the immediately following M) is performed within a specific period.

[0051] At least one of N, M and the specific period may be pre-specified in a specification, may be configured using higher layer signaling, may be determined based on UE capability information, or may be determined based on a combination of at least two of these.

[0052] In the following, in each embodiment of the present disclosure, details of each procedure will be described.

[0053] When the initial access procedure is performed for multiple carriers / bands, each procedure may be performed for the multiple carriers / bands.

[0054] Furthermore, when the initial access procedure is performed for multiple carriers / bands, each procedure may be performed for at least one of the multiple carriers / bands. For example, when the initial access procedure is performed for carrier #1, carrier #2, and carrier #3, the UE may transmit and receive signals in each procedure on at least one of carrier #1, carrier #2, and carrier #3.

[0055] In this case, the UE may transmit and receive signals in one procedure on the same / different carrier as the carrier on which it transmitted and received signals in another procedure.

[0056] A signal transmitted or received for a certain carrier may include information for procedure X for that certain carrier.

[0057] Signals transmitted and received on one carrier may include information for procedure X on another carrier.

[0058] The signals transmitted and received on the multiple carriers for a certain procedure X may contain all or at least some of the same information, or may contain different information.

[0059] The SS / PBCH blocks / SSBs / SIB1s / SIBx received by the UE may correspond one-to-one with the carriers / bands / cells, one-to-multiple, or multiple-to-one.

[0060] For example, the UE may receive a synchronization signal (e.g., an SS / PBCH block) corresponding to each carrier / cell and perform procedure A using resources corresponding to each synchronization signal.

[0061] Also, for example, the UE may receive (from one or more carriers / cells) a (common) synchronization signal (e.g., an SS / PBCH block) corresponding to multiple carriers / cells, and perform procedure A using resources corresponding to the synchronization signal.

[0062] The UE may receive a signal regarding procedure D from the carrier / band on which the initial access procedure has been completed.

[0063] The UE may also receive a signal regarding procedure D from a carrier / band other than the carrier / band on which the initial access procedure was completed.

[0064] At least one of the procedures A to D may be performed for a specific carrier / band / cell, which may be specified in advance, configured for the UE, determined based on UE capabilities, or a combination of at least two of these.

[0065] When the UE completes initial access with multiple cells, the UE may determine that a specific cell among the multiple cells is a PCell / special cell.

[0066] The particular cell may be pre-specified, may be configured for the UE, may be determined based on UE capabilities, or may be determined based on a combination of at least two of these.

[0067] The particular cell may be, for example, the cell with the lowest (or highest) cell ID (e.g., serving cell ID / physical cell ID / cell global ID), or the cell with the highest reception quality (e.g., RSRP) of the synchronization signal.

[0068] The number of carriers / cells available for initial access may be pre-specified, configured for the UE, determined based on UE capabilities, or a combination of at least two of these.

[0069] The UE capability may be, for example, a UE capability regarding the (maximum) number of SCells to be added. For example, the number of carriers / cells available for initial access may be equal to (the number of SCells that the UE can add) - 1.

[0070] First Embodiment The first embodiment relates to procedure A.

[0071] The UE may transmit PRACH (simultaneously / in parallel) on any of the carriers / bands.

[0072] The UE may perform procedure A when at least one of the following conditions is met: when a specific setting / notification is made by the base station / network (NW) and when a specific condition / situation is met.

[0073] The specific settings / notifications may be transmitted by specific signals / signaling.

[0074] The specific signal / signaling may be at least one of the following: SS / PBCH block / SIB1 / SIBx (x is an integer equal to or greater than 1) [of one / multiple cells / bands / carriers]; UE-specific (dedicated) RRC configuration / RRC release / RRC setup [of one / multiple cells / bands / carriers].

[0075] The UE may use the particular configuration / notification to (explicitly) configure / notify elements / parameters related to procedure X (e.g., at least one of procedures A to D) or to (implicitly) acquire elements / parameters related to procedure X.

[0076] The element / parameter related to procedure X may be information related to at least one of the following. For example, information related to at least one of the following may be configured in the UE, or a combination of elements / parameters related to at least two of the following information may be associated and configured in the UE: - (List of) executable / supportable procedure X; - (List of) carriers / bands [capable of executing procedure X); - Conditions for performing procedure X; - Fallback procedure; - Resources for procedure A / procedure B (e.g., time / frequency resources).

[0077] Regarding information regarding (a list of) carriers / bands [on which procedure X can be executed], for example, the (list of) carriers / bands may be associated and set for each specific (representative) frequency / cell / band.

[0078] The information about (a list of) carriers / bands (on which procedure X can be performed) may include information about (a list of) cell IDs, which may for example include at least one of the following: (a list of) serving cell indexes, (a list of) physical cell IDs (PCIs), (a list of) cell global IDs (CGIs).

[0079] The information about (a list of) carriers / bands [capable of executing procedure X] may include, for example, information about (a list of) frequencies. The (list of) frequencies may include, for example, at least one of the following: - Information about Absolute Radio Frequency Channel Numbers (ARFCNs) (for example, (a list of) ARFCN-XX (e.g., "XX" is "NR")); - (a list of) bands; - (a list of) band combinations.

[0080] The information about (a list of) carriers / bands [on which procedure X can be performed] may include, for example, information about (a list of) frequency directions (domains).

[0081] The (list of) information related to the frequency direction (domain) may include, for example, at least one of the following: - Information on a code point (e.g., k) corresponding to a specific bit of information related to the subcarrier offset of the SSB (e.g., Ssb-subcarrierOffset) ｓｓｂ ) (list of). - (list of) offsets relative to a specific frequency resource reference (which may be called, for example, point A, common resource block 0, etc.) - (list of) point A [in absolute frequency]. - (list of) subcarrier spacing for [SSB / SIB1 PDCCH / CORESET[0]]. - (list of) SSB-based Measurement Timing Configuration (SMTC). - (list of) information related to measurement objects (for example, measobject). - (list of) bandwidth for a specific CORESET (for example, CORESET0). - (list of) bandwidth for SIB1 PDCCH. - (list of) bandwidth for SSB.

[0082] The information regarding the conditions for performing procedure X may include information regarding the criteria [for each condition].

[0083] Regarding information regarding resources (e.g., time / frequency resources) for procedure A / procedure B, different time / frequency resources for procedure A / procedure B [specific between UEs / procedures / conditions] may be configured for each procedure A / each condition to be met (or to be met).

[0084] The resources for procedure A may be configured / determined based on information about at least one of the following: PRACH preamble format; Time resource; Frequency resource; Root sequence; PRACH configuration index (e.g., prach-ConfigurationIndex); Cyclic shift and restrict type (e.g., unrestricted, restricted set A, or restricted set B); PRACH occasion index; Set of PRACH occasion indices associated with a single [mask] index; PRACH occasion index or set of PRACH occasion indices associated with one SSB; Preamble index, or preamble index associated with one SSB / PRACH occasion; SSB and PRACH mapping information; Received signal strength (e.g., RSRP) threshold; Associated cyclic index.

[0085] The resource of Procedure B may refer to a specific resource (period) during which the UE attempts to receive or monitors the PDCCH associated with Msg. 2. The resource of Procedure B may be determined / configured based on one of the following, or a combination of at least two of the following: A random access response window (e.g., ra-ResponseWindow). A start position of the time during which the UE monitors the PDCCH (e.g., ra-ResponseStartTiming).

[0086] The PDCCH may be a PDCCH that schedules the PDSCH of the RAR configured / notified from the base station / network. The start position may be indicated using a specific time unit (e.g., slot unit / symbol unit / subframe unit / ms unit).

[0087] If the specific condition / condition is met, the specific condition / condition may be a condition / information related to at least one of the following: - A condition / condition related to synchronization; - A condition / condition related to pre-conditions; - A condition / condition related to signal / channel quality; - A condition / condition related to UE capabilities.

[0088] The synchronization conditions / situations may include at least one of the following: - (multiple carriers / bands) are co-located; - (multiple carriers / bands) a specific reference signal (e.g., periodic / non-periodic tracking CSI-RS (TRS)) is configured; - (multiple carriers) are intra-band / inter-band; - (multiple carriers / bands) have a specific relationship (e.g., the difference value between carriers / bands is smaller than a specific value, the carriers / bands are adjacent); - (multiple carriers / bands) are intra-frequency / inter-frequency; - (multiple carriers / bands) have a specific relationship (e.g., the difference value between frequencies is smaller than a specific value, the frequencies are adjacent); - (multiple carriers / bands) the frequency ranges are the same / different (e.g., FR1 / FR2 (FR2-1 / FR2-2)). - (Across multiple carriers / bands [between specific reference signals]) There is a specific QCL type (e.g., QCL type A / B / C / D) relationship. - (Across multiple carriers / bands) The round trip difference (RTD) is shorter than the cyclic prefix length corresponding to the subcarrier spacing [of a specific cell / frequency]. - (Across multiple carriers / bands) The power difference is smaller than a specific value (e.g., 3 dB).

[0089] The pre-conditions / situations may include at least one of the following: ・The UE is camped / accessed (for multiple carriers / bands). ・A specific configuration / notification is made from a specific layer (e.g., NAS (Non-Access Stratum) layer) (for multiple carriers / bands). ・The UE has specific information as stored information.

[0090] The prior state may refer to the state before the execution of procedure X (for example, procedure A).

[0091] The signal / channel quality conditions / situations may include, for example, that certain criteria for a particular reference signal (for multiple carriers / bands) are met.

[0092] The conditions / situations regarding the UE capabilities may be determined based on the implementation of the UE.

[0093] The fallback procedure (procedure A-1) related to procedure A will be described below.

[0094] If (in procedure A) a specific condition is not met [in a specific / any [multiple] carriers / bands], the UE may perform an action related to a specific procedure A [for a specific / single carrier / band] (procedure A-1).

[0095] For example, the case where the specific condition is not satisfied may include at least one of the following: - When a specific condition / situation between multiple carriers / bands (where procedure X can be executed) regarding the execution of procedure A [in a specific frequency / cell / band] is not satisfied. - When a configuration / notification from the base station / NW does not include a specific parameter that the UE is expected to include, or when the specific parameter has an unexpected value. - When a notification is not made from a higher layer (inside the UE) (e.g., RRC / MAC / NAS layer), or when a notification indicating failure is made from the higher layer.

[0096] The specific frequency / cell / band may refer to, for example, one or more (e.g., N or more) frequencies / cells / bands that are predefined / set.

[0097] The operations related to this particular procedure A may include, for example, transmitting a PRACH / Msg. 1 / random access preamble to a single existing carrier / band (e.g., as defined in 5G NR (pre-Rel. 20)).

[0098] Fig. 2 is a diagram showing an example of procedure A according to the first embodiment. In the example shown in Fig. 2, a UE performs an initial access procedure from carrier / band / cell #1 to #3. In the example shown in Fig. 2, the UE transmits PRACHs according to procedure A to carrier / band / cell #1 and #2.

[0099] According to the first embodiment described above, procedure A can be appropriately executed for a plurality of carriers / bands.

[0100] Second Embodiment The second embodiment relates to procedure B.

[0101] The UE may attempt to receive the RAR from any carrier / band (simultaneously / in parallel). The UE may monitor the PDCCH / search space / CORESET associated with the RAR from any carrier / band (simultaneously / in parallel).

[0102] The UE may receive RAR (PDSCH including RAR) from any [multiple] carriers / bands (simultaneously / in parallel).

[0103] The UE may perform procedure B when at least one of the following conditions is met: when a specific setting / notification is made by the base station / network (NW) and when a specific condition / situation is met.

[0104] The UE may assume that a specific parameter is included in the RAR received in procedure B. The UE may receive / obtain the specific parameter in procedure B.

[0105] The specific parameters may be, for example, parameters related to a cell / frequency / band / UE ID / Msg. 1 / Msg. 3.

[0106] The specific parameters may include information about (a list of) cell IDs, which may for example include at least one of the following: (a list of) serving cell indexes, (a list of) physical cell IDs (PCIs), (a list of) cell global IDs (CGIs).

[0107] The specific parameters may include, for example, information about (a list of) frequencies. The (list of) frequencies may include, for example, at least one of the following: - Information about ARFCN (for example, (a list of) ARFCN-XX (for example, "XX" is "NR")); - (a list of) bands; - (a list of) band combinations.

[0108] The specific parameters may include, for example, parameters related to UE ID / Msg. 1. The parameters related to UE ID / Msg. 1 may include, for example, at least one of the following: UE identifier; specific RNTI; RACH response ID.

[0109] The specific parameters may include, for example, parameters related to Msg. 3. The parameters related to Msg. 3 may include, for example, at least one of the following: Frequency hopping (whether or not), Frequency resource allocation, Time resource allocation, Modulation and Coding Scheme (MCS), Transmit Power Control (TPC) command, CSI report request, and SRS request.

[0110] Msg. 2 for a certain carrier / band may include the above-mentioned specific parameters for [some] of multiple carriers / bands. For example, a UE may use Msg. 2 for a certain carrier / band to receive [some] of the above-mentioned specific parameters corresponding to other carriers / the same carrier.

[0111] For each of the specific parameters, whether the specific parameter is to be notified using each carrier / band may be specified in advance or may be set by the base station.

[0112] For each of the specific parameters, whether the specific parameters for a plurality of carriers / bands in a certain carrier / band are notified may be specified in advance or may be set by the base station.

[0113] For RARs received (simultaneously / in parallel) from [multiple] carriers / bands, the UE may assume a specific transmission method. For RARs received (simultaneously / in parallel) from [multiple] carriers / bands, the UE may receive the RARs using a specific reception method.

[0114] For example, the UE may assume that a particular parameter (or a combination of said parameters) is at a predefined / configured value.

[0115] Also, for example, the UE may assume that the particular parameter (or a combination of the particular parameters) is common across multiple carriers / bands.

[0116] Also, for example, the UE may assume that the particular parameter (or combination of the particular parameters) has a particular relationship between multiple carriers / bands.

[0117] The specific relationship may be, for example, at least one of being within a specific range, satisfying a specific magnitude relationship, referring to a specific correspondence relationship (e.g., a specified / set table), or a specific number (e.g., X / more than X / less than X) of parameters being a specific value (e.g., 0 / 1).

[0118] The specific parameters may include, for example, information about at least one of the following: BWP, carrier, band, time resource, frequency resource, subcarrier spacing, search space, CORESET, redundancy version, RNTI, DCI format, MCS, precoder, and transform precoder.

[0119] The specific setting / notification may be the same as at least one of the signals / signaling / elements / parameters relating to the specific setting / notification described in the first embodiment above.

[0120] When the specific condition / circumstance is satisfied, the specific condition / circumstance may be the same as at least one of the specific conditions / circumstances described in the first embodiment.

[0121] The specific conditions / situations may also include that procedure A is being performed on (one or more predefined / configured) carriers / bands.

[0122] The fallback procedure (procedure B-1) related to procedure B will be described below.

[0123] If the UE is unable to receive Msg. 2 (in a specific / any (multiple) carriers / bands) (in procedure B), it may perform an action related to a specific procedure A (procedure B-1).

[0124] The failure to receive Msg. 2 may include at least one of the following: - When the UE fails to receive the PDSCH / PDCCH (e.g., PDSCH / PDCCH using the above-mentioned specific transmission / reception method) related to Msg. 2 within a specific period [in a specific frequency / cell / band]. - When multiple Msg. 2s do not include specific parameters that the UE is expected to include, or when the specific parameters have unexpected values ​​(e.g., when the assumptions regarding the specific parameters (or combinations of the specific parameters) are not met). - When a notification is not made from a higher layer (in the UE) (e.g., RRC / MAC / NAS layer) or when a notification indicating failure is made from the higher layer.

[0125] The specific frequency / cell / band may refer to, for example, one or more (e.g., N or more) frequencies / cells / bands that are predefined / set.

[0126] The actions related to the particular procedure A may include, for example, transmitting a PRACH / Msg. 1 / random access preamble on a particular carrier / band within a particular time period.

[0127] The actions relating to this particular procedure A may include, for example, making a particular notification (eg, a notification indicating a failure) to higher layers (inside the UE) (eg, RRC / MAC / NAS layers).

[0128] Fig. 3 is a diagram showing an example of procedure B according to the second embodiment. In the example shown in Fig. 3, a UE performs an initial access procedure from carrier / band / cell #1 to #3. In the example shown in Fig. 3, the UE transmits PRACH according to procedure A to carrier / band / cell #1 and #2. Thereafter, the UE receives Msg. 2 according to procedure B from carrier / band / cell #2.

[0129] According to the second embodiment, procedure B can be appropriately executed for a plurality of carriers / bands.

[0130] Third Embodiment The third embodiment relates to procedure C.

[0131] The UE may transmit Msg. 3 (simultaneously / in parallel) on any of the carriers / bands.

[0132] The UE may perform procedure C when at least one of the following conditions is met: when a specific setting / notification is made by the base station / network (NW) and when a specific condition / situation is met.

[0133] The UE may include certain parameters in the signal transmitted in procedure C.

[0134] The specific parameter may be, for example, a parameter that is [predefined / set] and differs for one or more (e.g., N) carriers / bands.

[0135] The specific parameters may be, for example, some parameters that are different / common for one or more (e.g., N) carriers / bands [defined / set in advance].

[0136] The specific parameter may be, for example, a parameter that is common to one or more (e.g., N) carriers / bands [predefined / set].

[0137] The specific parameters may for example include information about at least one of the following: UE identifier, TMSI (Temporary mobile subscriber identity), establishment cause, communication purpose, priority.

[0138] For Msg. 3 transmitted for multiple carriers / bands, the UE may use a specific transmission method.

[0139] For example, the UE may send Msg. 3 using an RRC setup request.

[0140] The case where the specific condition / situation is satisfied may include at least one of the following: - The parameters transmitted and received in procedure A and procedure B have a specific relationship; - Procedure A is performed on [one or more pre-defined / pre-set] carriers / bands; - Procedure B (reception of Msg. 2) is performed / completed within a specific period of time.

[0141] The execution / completion of procedure B within a specific period may mean, for example, that specific reception (e.g., all / some / immediately preceding [M] / immediately following [N] receptions) has occurred within a specific period on a certain carrier / band (one or more predefined / set).

[0142] Fig. 4 is a diagram showing an example of procedure C according to the third embodiment. In the example shown in Fig. 4, the UE performs an initial access procedure from carrier / band / cell #1 to #3. In the example shown in Fig. 4, the UE receives Msg. 2 according to procedure B from carrier / band / cell #2. Thereafter, the UE transmits Msg. 3 according to procedure C to carrier / band / cell #2 and #3.

[0143] According to the third embodiment, procedure C can be appropriately executed for a plurality of carriers / bands.

[0144] <Fourth Embodiment> The fourth embodiment relates to procedure D.

[0145] The UE may attempt to receive Msg. 4 from any carrier / band (simultaneously / in parallel) and may monitor the PDCCH / search space / CORESET associated with Msg. 4 from any carrier / band (simultaneously / in parallel).

[0146] The UE may receive Msg. 4 from any carrier / band (simultaneously / in parallel).

[0147] The UE may perform procedure D when at least one of the following conditions is met: when a specific setting / notification is made by the base station / network (NW) and when a specific condition / situation is met.

[0148] The UE may assume that a specific parameter is included in Msg. 4 received in procedure D. The UE may receive / acquire the specific parameter in procedure D.

[0149] The specific parameter may include, for example, information about a carrier / band on which Msg. 4 is received and / or information about a carrier / band other than the carrier / band on which Msg. 4 is received.

[0150] The UE may determine / judge a carrier / band on which contention resolution has been completed other than the carrier / band on which Msg. 4 is received, based on information about the carrier / band other than the carrier / band on which Msg. 4 is received.

[0151] The specific settings / notifications may include at least one of the information / parameters described in the first to third embodiments.

[0152] The case where the specific condition / circumstance is satisfied may include at least one of the conditions / circumstances described in the first to third embodiments.

[0153] The case where the specific condition / situation is satisfied may include at least one of the following: - The parameters transmitted and received in procedure A / procedure B / procedure C are in a specific relationship. - Procedure A / procedure C is performed on [one or more pre-defined / set] carriers / bands. - Procedure B (reception of Msg. 2) is performed / completed within a specific period of time.

[0154] Fig. 5 is a diagram showing an example of procedure D according to the fourth embodiment. In the example shown in Fig. 5, the UE performs an initial access procedure from carrier / band / cell #1 to #3. In the example shown in Fig. 5, the UE transmits Msg. 3 according to procedure C to carrier / band / cell #2 and #3. Thereafter, the UE receives Msg. 4 according to procedure D from carrier / band / cell #3.

[0155] According to the fourth embodiment described above, procedure D can be appropriately executed for a plurality of carriers / bands.

[0156] Fifth Embodiment The fifth embodiment relates to the terms / operations of the first to fourth embodiments.

[0157] The "specific period" described in the first to fourth embodiments above may be, for example, specified in advance, determined based on specific parameters set from the base station / network, determined based on UE capabilities, or determined based on a combination of at least two of these.

[0158] The "specific period" described in the first to fourth embodiments may be, for example, a period determined by a specific time width starting from a specific reference point.

[0159] The specific reference point may be, for example, at least one of the time of transmitting and receiving a specific DL / UL signal and a reference timing / time (e.g., system frame number (SFN) / slot number / symbol number) set by the base station.

[0160] The time domain unit of the particular reference point may be, for example, a symbol unit / slot unit / radio frame unit / system frame unit / subframe unit / sub-ms unit / ms unit / s unit.

[0161] The specific time width may be specified in advance, may be determined based on specific parameters set by the base station / network, may be determined based on UE capabilities, or may be determined based on a combination of at least two of these.

[0162] The particular time span may vary depending on the SCS, for example.

[0163] The particular time interval may vary depending on, for example, the timing advance value of the UE.

[0164] The particular time span may be defined / set / determined, for example, as a time window from the particular reference point.

[0165] The particular time span may be defined / set / determined, for example, as a delay (application delay / processing delay) from the particular reference point.

[0166] The UE may determine the specific period based on a comparison with a specific value. For example, the UE may determine the specific period to be the maximum / minimum value between a predefined / set / determined specific period and the specific value.

[0167] The specific value may be, for example, n symbols / slots / ms, where n may be, for example, 1 or any integer greater than or equal to 1.

[0168] The specific value may be specified in advance, may be determined based on specific parameters set by the base station / network, may be determined based on UE capabilities, or may be determined based on a combination of at least two of these.

[0169] The particular value may vary depending on the SCS, for example.

[0170] In the first to fourth embodiments, the term "carrier / band" may be replaced with "cell." In this case, the term "cell" may be a special cell (SpCell (e.g., PCell / PSCell)), PCell, PSCell (in DC mode), or (active) SCell, or any cell that satisfies a specific condition.

[0171] The first to fourth embodiments may be applied to a specific UE state / mode (e.g., at least one of an idle state, an inactive state, and an RRC connected state). For the first to fourth embodiments, different operations may be applied based on the UE state / mode.

[0172] The "specific configuration / notification" described in the first to fourth embodiments may be performed using, for example, RRC signaling / MAC CE / DCI.

[0173] Regarding the "specific setting / notification" described in the first to fourth embodiments, for example, an identifier / index may be associated with a parameter (list) that is set / notified using RRC signaling / MAC CE / DCI.

[0174] In this case, the UE may determine the parameters (list) to be activated / applied / used (or deactivated / not applied / not used) by receiving the identifier / index via another notification (e.g., MAC CE / DCI).

[0175] The identifier / index may be implicitly associated with the parameter / list based on the order of the list configured using RRC signaling, or may be explicitly numbered and associated with the parameter / list.

[0176] In at least one of the first to fourth embodiments, the UE may transmit a response signal (eg, NACK (Negative Acknowledgement) / ACK (Acknowledgement) / feedback / retransmission request) to the received signal.

[0177] The UE may configure / modify / release multiple parameter lists based on an add / modify list (e.g., AddModlist) / release list (e.g., releaselist) using RRC signaling.

[0178] The "specific configuration / notification" described in the first to fourth embodiments may be performed using, for example, a system information (SI) / SIB RRC message, or a UE-specific RRC message (e.g., RRCReconfiguration) for a UE during RRC connection. For example, the "specific configuration / notification" described in the first to fourth embodiments may be SS / PBCH block / SIB1 / SIBx / dedicated RRC configuration / RRC release / RRC setup [of a specific (one or more) carriers / bands].

[0179] The "specific setting / notification" described in the first to fourth embodiments above may be, for example, a DCI (DCI format) to which a CRC scrambled using a specific RNTI (e.g., X-RNTI) is attached.

[0180] The specific RNTI may be, for example, an existing RNTI (eg, NES (network energy saving)-RNTI, SI-RNTI) or a new RNTI.

[0181] The DCI format may be, for example, an existing DCI format or a new DCI format.

[0182] Any number described in the above first to fourth embodiments may be specified in advance, may be determined based on specific parameters set from the base station / network, may be determined based on UE capabilities, or may be determined based on a combination of at least two of these.

[0183] For any parameter described in the first to fourth embodiments, if the parameter is not set by the base station / NW, the UE may determine / decide to perform default operation.

[0184] The default action may be at least one of the following: - No action / cancel - Repeat the previous action (a specific number of times) - Perform RRC release - Perform RRC re-establishment - Send a specific notification to the base station / network - Send a specific notification to higher layers (in the UE).

[0185] For any parameter described in the first to fourth embodiments above, if the parameter is not set by the base station / NW, the UE may determine / decide to use a default value for the parameter.

[0186] The default value may be at least one of the following: A specific value (e.g., 0 / 1); The most recently used value; The most recently configured / notified value; A value predefined in a specification; Another configured / notified parameter value; A specific timer value.

[0187] For a certain UE action described in the first to fourth embodiments above, if the UE is unable to perform the UE action, the UE may determine / decide to perform another default action.

[0188] In at least one of the above first to fourth embodiments, a particular reference signal satisfying a particular criterion / condition may mean that the reception quality (e.g., RSRP / SINR) of the particular reference signal is greater than (or equal to or greater than) a particular threshold.

[0189] <Supplementary Information> <<Notification of Information to UE>> In the above-described embodiments, notification of any information to the UE [from a Network (NW) (e.g., a Base Station (BS))] (in other words, reception of any information from the BS by the UE) may be performed using physical layer signaling (e.g., DCI), higher layer signaling (e.g., RRC signaling, MAC CE), a specific signal / channel (e.g., PDCCH, PDSCH, reference signal), or a combination thereof.

[0190] When the notification is performed by a MAC CE, the MAC CE may be identified by including a new Logical Channel ID (LCID) in the MAC subheader, which is not defined in existing standards.

[0191] When the notification is made by DCI, the notification may be made by a specific field of the DCI, a Radio Network Temporary Identifier (RNTI) used to scramble Cyclic Redundancy Check (CRC) bits assigned to the DCI, the format of the DCI, etc.

[0192] Furthermore, notification of any information to the UE in the above embodiments may be performed periodically, semi-persistently, or aperiodically.

[0193] <<Notification of Information from UE>> In the above-described embodiments, notification of any information from the UE [to the NW] (in other words, transmission / report of any information from the UE to the BS) may be performed using physical layer signaling (e.g., UCI), higher layer signaling (e.g., RRC signaling, MAC CE), a specific signal / channel (e.g., PUCCH, PUSCH, PRACH, reference signal), or a combination thereof.

[0194] When the notification is performed by a MAC CE, the MAC CE may be identified by including a new LCID, which is not defined in existing standards, in the MAC subheader.

[0195] If the notification is made by UCI, the notification may be transmitted using PUCCH or PUSCH.

[0196] Furthermore, any information in the above-described embodiments may be notified from the UE periodically, semi-persistently, or aperiodically.

[0197] <<Application of Each Embodiment>> In a UE / BS, specific (one or more) processes / operations / controls / assumptions / information for at least one of the above-described embodiments may be applied (used) when one or more of the following conditions are met: - A higher layer parameter indicating the specific processes / operations / controls / assumptions / information is configured. - The specific processes / operations / controls / assumptions / information is determined based on related higher layer parameters. - The specific processes / operations / controls / assumptions / information is specified / activated / triggered by a MAC CE / DCI / UCI / resource / channel / RS. - A specific UE capability indicating (or related to) the specific processes / operations / controls / assumptions / information is reported or supported. - The application of the specific processes / operations / controls / assumptions / information is determined based on specific conditions.

[0198] The particular UE capability may indicate that the particular process / action / control / assumption / information is supported.

[0199] Furthermore, the above-mentioned specific UE capability may be a capability that is applied across all frequencies (commonly regardless of frequency), or may be a capability for each frequency (e.g., one or a combination of UE, cell, band, band combination, BWP, component carrier, etc.), or may be a capability for each frequency range (e.g., Frequency Range 1 (FR1), FR2, FR3, FR4, FR5, FR2-1, FR2-2), or may be a capability for each subcarrier spacing (SubCarrier Spacing (SCS)), or may be a capability for each Feature Set (FS) or Feature Set Per Component-carrier (FSPC).

[0200] Furthermore, the specific UE capability may be a capability that is applied to all duplexing methods (commonly regardless of the duplexing method), or may be a capability for each duplexing method (e.g., Time Division Duplex (TDD) or Frequency Division Duplex (FDD)).

[0201] If the above conditions are not met, the UE / BS may follow the behavior specified in existing 3GPP releases.

[0202] (Supplementary Notes) The following inventions are supplemented with respect to one embodiment of the present disclosure. [Supplementary Note 1-1] A terminal having a transmitter that transmits a first message related to an initial access procedure for a plurality of cells to at least one of the plurality of cells, and a controller that controls reception of a second message transmitted from at least one of the plurality of cells in response to the first message. [Supplementary Note 1-2] The terminal according to Supplementary Note 1-1, wherein the first message includes information regarding a resource for receiving the second message. [Supplementary Note 1-3] The terminal according to Supplementary Note 1-1 or Supplementary Note 1-2, wherein the controller controls transmission of the first message based on at least one of a specific setting and a specific condition. [Supplementary Note 1-4] The terminal according to any of Supplements 1-1 to 1-3, wherein the transmitter transmits the first message to at least two of the plurality of cells. [Supplementary Note 2-1] A terminal having a receiving unit that receives a second message related to an initial access procedure for a plurality of cells from at least one of the plurality of cells, and a control unit that controls transmission of a third message to at least one of the plurality of cells based on the second message. [Supplementary Note 2-2] The terminal according to Supplementary Note 2-1, wherein the second message includes information related to a resource for transmitting the third message. [Supplementary Note 2-3] The terminal according to Supplementary Note 2-1 or Supplementary Note 2-2, wherein the control unit controls reception of the second message based on at least one of a specific setting and a specific condition. [Supplementary Note 2-4] The terminal according to any of Supplements 2-1 to 2-3, wherein the receiving unit receives a fourth message transmitted based on the third message from at least one of the plurality of cells.

[0203] (Wireless Communication System) The configuration of a wireless communication system according to an embodiment of the present disclosure will be described below. In this wireless communication system, communication is performed using any one of the wireless communication methods according to the above embodiments of the present disclosure or a combination thereof.

[0204] 6 is a diagram illustrating an example of a schematic configuration of a wireless communication system according to an embodiment. The wireless communication system 1 (which may be simply referred to as system 1) may be a system that realizes communication using Long Term Evolution (LTE) or 5th generation mobile communication system New Radio (5G NR) specified by the Third Generation Partnership Project (3GPP).

[0205] The wireless communication system 1 may also support dual connectivity between multiple Radio Access Technologies (RATs) (Multi-RAT Dual Connectivity (MR-DC)). MR-DC may include dual connectivity between LTE (Evolved Universal Terrestrial Radio Access (E-UTRA)) and NR (E-UTRA-NR Dual Connectivity (EN-DC)), dual connectivity between NR and LTE (NR-E-UTRA Dual Connectivity (NE-DC)), etc.

[0206] In EN-DC, the LTE (E-UTRA) base station (eNB) is the master node (Master Node (MN)), and the NR base station (gNB) is the secondary node (Secondary Node (SN)). In NE-DC, the NR base station (gNB) is the MN, and the LTE (E-UTRA) base station (eNB) is the SN.

[0207] The wireless communication system 1 may support dual connectivity between multiple base stations within the same RAT (for example, dual connectivity in which both the MN and SN are NR base stations (gNBs) (NR-NR Dual Connectivity (NN-DC))).

[0208] The wireless communication system 1 may include a base station 11 that forms a macrocell C1 with a relatively wide coverage, and base stations 12 (12a-12c) that are located within the macrocell C1 and form small cells C2 that are smaller than the macrocell C1. A user terminal 20 may be located within at least one of the cells. The location, number, shape, size, etc. of each cell and user terminal 20 are not limited to the embodiment shown in the figure. Hereinafter, when there is no need to distinguish between the base stations 11 and 12, they will be collectively referred to as the base station 10.

[0209] The wireless communication system 1 may utilize multi-input multi-output (MIMO). For example, one cell may be formed by one antenna / base station 10, or may be formed by multiple antennas / base stations 10. One [virtual] cell (which may be called, for example, a supercell) may be composed of multiple [virtual] cells (which may be called, for example, subcells). A supercell may correspond to a cell with a fixed physical range, and a subcell may correspond to a cell with a quasi-static / dynamically variable physical range. In this case, the wireless communication system 1 may be called a cell-free system.

[0210] The user terminal 20 may be connected to at least one of the multiple base stations 10. The user terminal 20 may utilize at least one of carrier aggregation (CA) using multiple component carriers (CCs) and dual connectivity (DC).

[0211] Each CC may be included in at least one of a first frequency band (Frequency Range 1 (FR1)) and a second frequency band (Frequency Range 2 (FR2)). The macro cell C1 may be included in FR1, and the small cell C2 may be included in FR2. For example, FR1 may be a frequency band of 6 GHz or less (sub-6 GHz), and FR2 may be a frequency band higher than 24 GHz (above-24 GHz). Note that the frequency bands and definitions of FR1 and FR2 are not limited to these, and for example, FR1 may correspond to a higher frequency band than FR2.

[0212] Furthermore, the user terminal 20 may perform communication using at least one of time division duplex (TDD) and frequency division duplex (FDD) in each CC.

[0213] The multiple base stations 10 may be connected by wire (e.g., optical fiber compliant with the Common Public Radio Interface (CPRI), an X2 / Xn interface, etc.) or wirelessly (e.g., NR communication). For example, when NR communication is used as a backhaul between the base stations 11 and 12, the base station 11 corresponding to the upper station may be called an Integrated Access Backhaul (IAB) donor, and the base station 12 corresponding to the relay station (relay) may be called an IAB node.

[0214] The base station 10 may be connected to the core network 30 directly or via another base station 10. The core network 30 may include, for example, at least one of an Evolved Packet Core (EPC), a 5G Core Network (5GCN), a Next Generation Core (NGC), and the like.

[0215] The core network 30 may include network functions (Network Functions (NF)) such as a User Plane Function (UPF), an Access and Mobility management Function (AMF), a Session Management Function (SMF), a Unified Data Management (UDM), an Application Function (AF), a Data Network (DN), a Location Management Function (LMF), and Operation, Administration and Maintenance (Management) (OAM). A single network node may provide multiple functions. Communication with an external network (e.g., the Internet) may also be performed via the DN.

[0216] The user terminal 20 may be a terminal that supports at least one of communication methods such as LTE, LTE-A, and 5G.

[0217] An Orthogonal Frequency Division Multiplexing (OFDM)-based radio access scheme may be used in the wireless communication system 1. For example, Cyclic Prefix OFDM (CP-OFDM), Discrete Fourier Transform Spread OFDM (DFT-s-OFDM), Orthogonal Frequency Division Multiple Access (OFDMA), Single Carrier Frequency Division Multiple Access (SC-FDMA), or the like may be used in at least one of the downlink (DL) and uplink (UL).

[0218] The radio access scheme may also be called a waveform. Note that in the wireless communication system 1, other radio access schemes (e.g., other single-carrier transmission schemes, other multi-carrier transmission schemes) may be used as the UL and DL radio access schemes.

[0219] In the wireless communication system 1, a downlink shared channel (Physical Downlink Shared Channel (PDSCH)) shared by each user terminal 20, a broadcast channel (Physical Broadcast Channel (PBCH)), a downlink control channel (Physical Downlink Control Channel (PDCCH)), etc. may be used as the downlink channel.

[0220] Furthermore, in the wireless communication system 1, an uplink shared channel (Physical Uplink Shared Channel (PUSCH)) shared by each user terminal 20, an uplink control channel (Physical Uplink Control Channel (PUCCH)), a random access channel (Physical Random Access Channel (PRACH)), or the like may be used as an uplink channel.

[0221] The PDSCH transmits user data, higher layer control information, a System Information Block (SIB), etc. The PUSCH may transmit user data, higher layer control information, etc. Furthermore, the PBCH may transmit a Master Information Block (MIB).

[0222] Lower layer control information may be transmitted by the PDCCH. The lower layer control information may include, for example, Downlink Control Information (DCI) including scheduling information for at least one of the PDSCH and the PUSCH.

[0223] Note that the DCI for scheduling the PDSCH may be referred to as a DL assignment, a DL DCI, etc., and the DCI for scheduling the PUSCH may be referred to as a UL grant, a UL DCI, etc. Note that the PDSCH may be replaced with DL data, and the PUSCH may be replaced with UL data.

[0224] A control resource set (CORESET) and a search space may be used to detect the PDCCH. The CORESET corresponds to resources for searching for DCI. The search space corresponds to a search region and a search method for PDCCH candidates. One CORESET may be associated with one or more search spaces. The UE may monitor the CORESET associated with a certain search space based on the search space configuration.

[0225] One search space may correspond to PDCCH candidates corresponding to one or more aggregation levels. One or more search spaces may be referred to as a search space set. Note that the terms "search space," "search space set," "search space configuration," "search space set configuration," "CORESET," "CORESET configuration," and the like in the present disclosure may be read interchangeably.

[0226] The PUCCH may transmit uplink control information (UCI) including at least one of channel state information (CSI), delivery confirmation information (which may be called, for example, Hybrid Automatic Repeat reQuest ACKnowledgement (HARQ-ACK), ACK / NACK, etc.), and scheduling request (SR). The PRACH may transmit a random access preamble for establishing a connection with a cell.

[0227] In the present disclosure, downlink, uplink, etc. may be expressed without adding "link." Also, various channels may be expressed without adding "Physical" to the beginning.

[0228] In the wireless communication system 1, a synchronization signal (SS), a downlink reference signal (DL-RS), etc. may be transmitted. In the wireless communication system 1, as the DL-RS, a cell-specific reference signal (CRS), a channel state information reference signal (CSI-RS), a demodulation reference signal (DMRS), a positioning reference signal (PRS), a phase tracking reference signal (PTRS), etc. may be transmitted.

[0229] The synchronization signal may be, for example, at least one of a Primary Synchronization Signal (PSS) and a Secondary Synchronization Signal (SSS). A signal block including an SS (PSS, SSS) and a PBCH (and a DMRS for the PBCH) may be referred to as an SS / PBCH block, an SS Block (SSB), or the like. Note that the SS, SSB, and the like may also be referred to as a reference signal.

[0230] Furthermore, in the wireless communication system 1, a sounding reference signal (SRS), a demodulation reference signal (DMRS), or the like may be transmitted as an uplink reference signal (UL-RS). Note that the DMRS may also be called a user equipment-specific reference signal (UE-specific reference signal).

[0231] 7 is a diagram showing an example of the configuration of a base station according to an embodiment. The base station 10 includes a control unit 110, a transceiver unit 120, a transceiver antenna 130, and a transmission line interface 140. Note that the base station may include one or more of each of the control unit 110, the transceiver unit 120, the transceiver antenna 130, and the transmission line interface 140.

[0232] In this example, the functional blocks of the characteristic parts of the present embodiment are mainly shown, and it may be assumed that the base station 10 also has other functional blocks necessary for wireless communication. Some of the processing of each unit described below may be omitted.

[0233] The control unit 110 performs overall control of the base station 10. The control unit 110 can be configured from a controller, a control circuit, and the like that are explained based on common understanding in the technical field to which the present disclosure relates.

[0234] The control unit 110 may control signal generation, scheduling (e.g., resource allocation, mapping), etc. The control unit 110 may control transmission and reception using the transceiver unit 120, the transceiver antenna 130, and the transmission path interface 140, measurement, etc. The control unit 110 may generate data, control information, sequences, etc. to be transmitted as signals, and transfer them to the transceiver unit 120. The control unit 110 may perform call processing (setting up, releasing, etc.) of communication channels, status management of the base station 10, management of radio resources, etc.

[0235] The transceiver unit 120 may include a baseband unit 121, a radio frequency (RF) unit 122, and a measurement unit 123. The baseband unit 121 may include a transmission processing unit 1211 and a reception processing unit 1212. The transceiver unit 120 may be configured with a transmitter / receiver, an RF circuit, a baseband circuit, a filter, a phase shifter, a measurement circuit, a transceiver circuit, etc., which are described based on common understanding in the technical field related to the present disclosure.

[0236] The transmitting / receiving unit 120 may be configured as an integrated transmitting / receiving unit, or may be configured from a transmitting unit and a receiving unit. The transmitting unit may be configured from a transmission processing unit 1211 and an RF unit 122. The receiving unit may be configured from a reception processing unit 1212, the RF unit 122, and a measurement unit 123.

[0237] The transmitting and receiving antenna 130 can be configured from an antenna described based on common understanding in the technical field to which the present disclosure relates, such as an array antenna.

[0238] The transceiver 120 may transmit the above-mentioned downlink channel, synchronization signal, downlink reference signal, etc. The transceiver 120 may receive the above-mentioned uplink channel, uplink reference signal, etc.

[0239] The transceiver 120 may form at least one of the transmit beam and the receive beam using digital beamforming (e.g., precoding), analog beamforming (e.g., phase rotation), or the like.

[0240] The transmitter / receiver unit 120 (transmission processing unit 1211) may perform Packet Data Convergence Protocol (PDCP) layer processing, Radio Link Control (RLC) layer processing (e.g., RLC retransmission control), Medium Access Control (MAC) layer processing (e.g., HARQ retransmission control), etc. on data, control information, etc. obtained from the control unit 110, and generate a bit string to be transmitted.

[0241] The transmitter / receiver unit 120 (transmission processing unit 1211) may perform transmission processing such as channel coding (which may include error correction coding), modulation, mapping, filtering, Discrete Fourier Transform (DFT) processing (if necessary), Inverse Fast Fourier Transform (IFFT) processing, precoding, and digital-to-analog conversion on the bit string to be transmitted, and output a baseband signal.

[0242] The transceiver unit 120 (RF unit 122) may perform modulation, filtering, amplification, etc. on the baseband signal to a radio frequency band, and transmit the radio frequency band signal via the transceiver antenna 130.

[0243] On the other hand, the transceiver unit 120 (RF unit 122) may perform amplification, filtering, demodulation to a baseband signal, etc. on the radio frequency band signal received by the transceiver antenna 130.

[0244] The transceiver 120 (reception processing unit 1212) may apply reception processing such as analog-to-digital conversion, Fast Fourier Transform (FFT) processing, Inverse Discrete Fourier Transform (IDFT) processing (if necessary), filtering, demapping, demodulation, decoding (which may include error correction decoding), MAC layer processing, RLC layer processing, and PDCP layer processing to the acquired baseband signal, thereby acquiring user data, etc.

[0245] The transceiver 120 (measurement unit 123) may perform measurements on the received signal. For example, the measurement unit 123 may perform Radio Resource Management (RRM) measurements, Channel State Information (CSI) measurements, etc. based on the received signal. The measurement unit 123 may measure received power (e.g., Reference Signal Received Power (RSRP)), received quality (e.g., Reference Signal Received Quality (RSRQ), Signal to Interference plus Noise Ratio (SINR), Signal to Noise Ratio (SNR)), signal strength (e.g., Received Signal Strength Indicator (RSSI)), propagation path information (e.g., CSI), etc. The measurement results may be output to the control unit 110.

[0246] The transmission path interface 140 may transmit and receive signals (backhaul signaling) between devices included in the core network 30 (e.g., network nodes that provide NF), other base stations 10, etc., and may acquire and transmit user data (user plane data), control plane data, etc. for the user terminal 20.

[0247] The transmitting section and receiving section of the base station 10 in the present disclosure may be configured by at least one of the transmitting / receiving section 120, the transmitting / receiving antenna 130, and the transmission path interface 140.

[0248] The base station 10 may be separated into three elements: a radio unit (RU), a distributed unit (DU), and a central unit (CU). For example, the RU may implement RF processing (digital beamforming, digital-to-analog conversion, analog beamforming, etc.) and lower-level functions of the physical layer (precoding, IFFT, FFT, etc.). The DU may implement higher-level functions of the physical layer (coding to resource element mapping, etc.), MAC layer functions, and RLC layer functions. The CU may implement the functions of the PDCP layer, Service Data Adaptation Protocol (SDAP) layer, and RRC layer.

[0249] In the present disclosure, the base station 10 may include a single device that realizes all of the functions of the RU, DU, and CU, or may include multiple devices that each realize some of the functions of the RU, DU, and CU and are connected to each other. In the present disclosure, the base station 10 may be interchangeably read as RU / DU / CU.

[0250] The transceiver 120 may receive a first message related to the initial access procedure, the first message being transmitted to at least two of the plurality of cells, and the controller 110 may control transmission of a second message in response to the first message (first and second embodiments).

[0251] The transceiver 120 may transmit a second message related to the initial access procedure to a plurality of cells, and the controller 110 may control reception of a third message transmitted to at least two of the plurality of cells based on the second message (second and third embodiments).

[0252] (User Terminal) Fig. 8 is a diagram showing an example of the configuration of a user terminal according to one embodiment. The user terminal 20 includes a control unit 210, a transceiver unit 220, and a transceiver antenna 230. Note that the user terminal may include one or more of each of the control unit 210, the transceiver unit 220, and the transceiver antenna 230.

[0253] In this example, the functional blocks of the characteristic parts of the present embodiment are mainly shown, and it may be assumed that the user terminal 20 also has other functional blocks necessary for wireless communication. Some of the processing of each unit described below may be omitted.

[0254] The control unit 210 performs overall control of the user terminal 20. The control unit 210 can be configured from a controller, a control circuit, etc., which are described based on common understanding in the technical field to which the present disclosure relates.

[0255] The control unit 210 may control signal generation, mapping, etc. The control unit 210 may control transmission and reception, measurement, etc. using the transceiver unit 220 and the transceiver antenna 230. The control unit 210 may generate data, control information, sequences, etc. to be transmitted as signals and transfer them to the transceiver unit 220.

[0256] The transceiver unit 220 may include a baseband unit 221, an RF unit 222, and a measurement unit 223. The baseband unit 221 may include a transmission processing unit 2211 and a reception processing unit 2212. The transceiver unit 220 may be configured with a transmitter / receiver, an RF circuit, a baseband circuit, a filter, a phase shifter, a measurement circuit, a transceiver circuit, etc., which are described based on common understanding in the technical field related to the present disclosure.

[0257] The transmitting / receiving unit 220 may be configured as an integrated transmitting / receiving unit, or may be composed of a transmitting unit and a receiving unit. The transmitting unit may be composed of a transmission processing unit 2211 and an RF unit 222. The receiving unit may be composed of a reception processing unit 2212, an RF unit 222, and a measurement unit 223.

[0258] The transmitting / receiving antenna 230 can be configured from an antenna described based on common understanding in the technical field to which the present disclosure relates, such as an array antenna.

[0259] The transceiver 220 may receive the above-mentioned downlink channel, synchronization signal, downlink reference signal, etc. The transceiver 220 may transmit the above-mentioned uplink channel, uplink reference signal, etc.

[0260] The transceiver unit 220 may form at least one of the transmit beam and the receive beam using digital beamforming (e.g., precoding), analog beamforming (e.g., phase rotation), or the like.

[0261] The transceiver unit 220 (transmission processing unit 2211) may perform PDCP layer processing, RLC layer processing (e.g., RLC retransmission control), MAC layer processing (e.g., HARQ retransmission control), etc. on data, control information, etc. obtained from the control unit 210, and generate a bit string to be transmitted.

[0262] The transmitter / receiver unit 220 (transmission processing unit 2211) may perform transmission processing such as channel coding (which may include error correction coding), modulation, mapping, filtering, DFT processing (if necessary), IFFT processing, precoding, and digital-to-analog conversion on the bit string to be transmitted, and output a baseband signal.

[0263] Whether or not to apply DFT processing may be based on the setting of transform precoding. When transform precoding is enabled for a certain channel (e.g., PUSCH), the transceiver unit 220 (transmission processing unit 2211) may perform DFT processing as the transmission processing to transmit the channel using a DFT-s-OFDM waveform, and if not, it may not be necessary to perform DFT processing as the transmission processing.

[0264] The transceiver unit 220 (RF unit 222) may perform modulation, filtering, amplification, etc. on the baseband signal to a radio frequency band, and transmit the radio frequency band signal via the transceiver antenna 230.

[0265] On the other hand, the transceiver unit 220 (RF unit 222) may perform amplification, filtering, demodulation to a baseband signal, etc. on the radio frequency band signal received by the transceiver antenna 230.

[0266] The transceiver unit 220 (reception processing unit 2212) may apply reception processing such as analog-to-digital conversion, FFT processing, IDFT processing (if necessary), filtering, demapping, demodulation, decoding (which may include error correction decoding), MAC layer processing, RLC layer processing, and PDCP layer processing to the acquired baseband signal, and acquire user data, etc.

[0267] The transceiver 220 (measurement unit 223) may perform measurements on the received signal. For example, the measurement unit 223 may perform RRM measurements, CSI measurements, etc. based on the received signal. The measurement unit 223 may measure received power (e.g., RSRP), received quality (e.g., RSRQ, SINR, SNR), signal strength (e.g., RSSI), propagation path information (e.g., CSI), etc. The measurement results may be output to the control unit 210.

[0268] The measurement unit 223 may derive channel measurements for CSI calculation based on the channel measurement resources. The channel measurement resources may be, for example, non-zero power (NZP) CSI-RS resources. The measurement unit 223 may also derive interference measurements for CSI calculation based on the interference measurement resources. The interference measurement resources may be at least one of an NZP CSI-RS resource for interference measurement, a CSI-Interference Measurement (IM) resource, etc. Note that CSI-IM may be referred to as CSI-Interference Management (IM) or may be interchangeably read as Zero Power (ZP) CSI-RS. Note that in the present disclosure, CSI-RS, NZP CSI-RS, ZP CSI-RS, CSI-IM, CSI-SSB, etc. may be interchangeably read as interchangeable.

[0269] The transmitting unit and receiving unit of the user terminal 20 in the present disclosure may be configured by at least one of the transmitting / receiving unit 220 and the transmitting / receiving antenna 230.

[0270] The transceiver 220 may transmit a first message related to an initial access procedure for a plurality of cells to at least one of the plurality of cells, and the controller 210 may control reception of a second message transmitted from at least one of the plurality of cells in response to the first message (first and second embodiments).

[0271] The first message may include information about a resource that receives the second message (first embodiment).

[0272] The control unit 210 may control the transmission of the first message based on at least one of a specific setting and a specific condition (first embodiment).

[0273] The transceiver unit 220 may transmit the first message to at least two of the plurality of cells (first embodiment).

[0274] The transceiver unit 220 may receive a second message related to an initial access procedure for the plurality of cells from at least one of the plurality of cells, and the control unit 210 may control transmission of a third message to at least one of the plurality of cells based on the second message (second and third embodiments).

[0275] The second message may include information about a resource for transmitting the third message (second embodiment).

[0276] The control unit 210 may control the reception of the second message based on at least one of a specific setting and a specific condition (second embodiment).

[0277] The transceiver unit 220 may receive a fourth message transmitted based on the third message from at least one of the plurality of cells (fourth embodiment).

[0278] (Hardware Configuration) Note that the block diagrams used to explain the above embodiments show functional blocks. These functional blocks (components) are realized by any combination of at least one of hardware and software. Furthermore, the method for realizing each functional block is not particularly limited. That is, each functional block may be realized using a single device that is physically or logically coupled, or may be realized using two or more physically or logically separated devices that are directly or indirectly connected (for example, using wires, wirelessly, etc.) and these multiple devices. The functional block may be realized by combining software with the single device or the multiple devices.

[0279] Here, the functions include, but are not limited to, judgment, determination, judgment, calculation, computation, processing, derivation, investigation, search, confirmation, reception, transmission, output, access, resolution, selection, election, establishment, comparison, assumption, expectation, deeming, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating, mapping, and assignment. For example, a functional block (component) that performs transmission may be called a transmitting unit, transmitter, etc. As described above, the implementation method of each is not particularly limited.

[0280] For example, a base station, a user terminal, etc. according to an embodiment of the present disclosure may function as a computer that performs processing of the wireless communication method of the present disclosure. Fig. 9 is a diagram illustrating an example of the hardware configuration of a base station and a user terminal according to an embodiment. The above-described base station 10 and user terminal 20 may be physically configured as a computer device including a processor 1001, a memory 1002, a storage 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, etc.

[0281] In the present disclosure, the terms apparatus, circuit, device, section, unit, etc. may be used interchangeably. The hardware configurations of the base station 10 and the user terminal 20 may be configured to include one or more of the devices shown in the drawings, or may be configured to exclude some of the devices.

[0282] For example, although only one processor 1001 is shown, there may be multiple processors. Furthermore, processing may be performed by one processor, or processing may be performed by two or more processors simultaneously, serially, or in other ways. Furthermore, processor 1001 may be implemented by one or more chips.

[0283] Each function in the base station 10 and the user terminal 20 is realized, for example, by loading specified software (programs) onto hardware such as a processor 1001 and a memory 1002, causing the processor 1001 to perform calculations, control communication via the communication device 1004, and control at least one of reading and writing data in the memory 1002 and the storage 1003.

[0284] The processor 1001, for example, runs an operating system to control the entire computer. The processor 1001 may be configured as a central processing unit (CPU) including an interface with peripheral devices, a control device, an arithmetic unit, a register, etc. For example, at least a part of the above-mentioned control unit 110 (210), transceiver unit 120 (220), etc. may be realized by the processor 1001.

[0285] The processor 1001 also reads programs (program codes), software modules, data, etc. from at least one of the storage 1003 and the communication device 1004 into the memory 1002 and executes various processes in accordance with these. The programs used are those that cause a computer to execute at least some of the operations described in the above-described embodiments. For example, the control unit 110 (210) may be implemented by a control program stored in the memory 1002 and running on the processor 1001, and the other functional blocks may be implemented in a similar manner.

[0286] The memory 1002 is a computer-readable recording medium and may be configured by at least one of, for example, Read Only Memory (ROM), Erasable Programmable ROM (EPROM), Electrically EEPROM (EEPROM), Random Access Memory (RAM), or other suitable storage medium. The memory 1002 may also be referred to as a register, cache, main memory, etc. The memory 1002 may store executable programs (program codes), software modules, etc. for implementing a wireless communication method according to an embodiment of the present disclosure.

[0287] Storage 1003 is a computer-readable recording medium and may be composed of at least one of, for example, a flexible disk, a floppy disk, a magneto-optical disk (e.g., a compact disc (e.g., a Compact Disc ROM (CD-ROM)), a digital versatile disc, a Blu-ray disc), a removable disk, a hard disk drive, a smart card, a flash memory device (e.g., a card, a stick, a key drive), a magnetic stripe, a database, a server, or other suitable storage medium. Storage 1003 may also be referred to as an auxiliary storage device.

[0288] The communication device 1004 is hardware (transmission / reception device) for communicating between computers via at least one of a wired network and a wireless network, and is also referred to as, for example, a network device, a network controller, a network card, or a communication module. The communication device 1004 may be configured to include a high-frequency switch, a duplexer, a filter, a frequency synthesizer, etc. to realize at least one of frequency division duplex (FDD) and time division duplex (TDD). For example, the above-mentioned transmission / reception unit 120 (220), transmission / reception antenna 130 (230), etc. may be realized by the communication device 1004. The transmission / reception unit 120 (220) may be implemented as a transmission unit 120a (220a) and a reception unit 120b (220b) that are physically or logically separated.

[0289] The input device 1005 is an input device (e.g., a keyboard, a mouse, a microphone, a switch, a button, a sensor, etc.) that accepts input from the outside. The output device 1006 is an output device (e.g., a display, a speaker, a light emitting diode (LED) lamp, etc.) that outputs to the outside. Note that the input device 1005 and the output device 1006 may be integrated into one device (e.g., a touch panel).

[0290] 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.

[0291] Furthermore, the base station 10 and the user terminal 20 may be configured to include hardware such as a microprocessor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a programmable logic device (PLD), or a field programmable gate array (FPGA), and some or all of the functional blocks may be realized using this hardware. For example, the processor 1001 may be implemented using at least one of these pieces of hardware.

[0292] In addition, the devices included in the core network 30 (for example, network nodes that provide NF) may also be realized by the above-mentioned functional block / hardware configuration.

[0293] (Modifications) Note that terms described in the present disclosure and terms necessary for understanding the present disclosure may be replaced with terms having the same or similar meanings. For example, a channel, a symbol, and a signal (signal or signaling) may be interchangeable. A signal may also be a message. A reference signal may be abbreviated as RS, and may also be called a pilot, pilot signal, etc. depending on the applicable standard. A component carrier (CC) may also be called a cell, frequency carrier, carrier frequency, etc.

[0294] A radio frame may be composed of one or more periods (frames) in the time domain. Each of the one or more periods (frames) constituting a radio frame may be called a subframe. Furthermore, a subframe may be composed of one or more slots in the time domain. A subframe may have a fixed time length (e.g., 1 ms) that is independent of numerology.

[0295] Here, the numerology may be a communication parameter applied to at least one of transmission and reception of a signal or channel, and may indicate at least one of, for example, Subcarrier Spacing (SCS), bandwidth, symbol length, cyclic prefix length, Transmission Time Interval (TTI), number of symbols per TTI, radio frame structure, specific filtering performed by a transceiver in the frequency domain, and specific windowing performed by a transceiver in the time domain.

[0296] A slot may be composed of one or more symbols (such as an Orthogonal Frequency Division Multiplexing (OFDM) symbol or a Single Carrier Frequency Division Multiple Access (SC-FDMA) symbol) in the time domain. A slot may also be a time unit based on numerology.

[0297] A slot may include multiple minislots. Each minislot may consist of one or multiple symbols in the time domain. A minislot may also be called a subslot. A minislot may consist of fewer symbols than a slot. A PDSCH (or PUSCH) transmitted in a time unit larger than a minislot may be called PDSCH (PUSCH) mapping type A. A PDSCH (or PUSCH) transmitted using a minislot may be called PDSCH (PUSCH) mapping type B.

[0298] A radio frame, a subframe, a slot, a minislot, and a symbol all represent time units for transmitting signals. The radio frame, the subframe, the slot, the minislot, and the symbol may be referred to by other names corresponding to the radio frame, the subframe, the slot, the minislot, and the symbol. Note that the time units such as a frame, a subframe, a slot, a minislot, and a symbol in the present disclosure may be interchangeable.

[0299] For example, one subframe may be referred to as a TTI, or multiple consecutive subframes may be referred to as a TTI, or one slot or one minislot may be referred to as a TTI. That is, at least one of the subframe and the TTI may be a subframe (1 ms) in existing LTE, a period shorter than 1 ms (for example, 1-13 symbols), or a period longer than 1 ms. Note that the unit representing the TTI may be called a slot, minislot, etc. instead of a subframe.

[0300] Here, TTI refers to, for example, the smallest time unit for scheduling in wireless communication. For example, in an LTE system, a base station performs scheduling to allocate radio resources (such as frequency bandwidth and transmission power that can be used by each user terminal) to each user terminal in TTI units. Note that the definition of TTI is not limited to this.

[0301] 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.

[0302] 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.

[0303] A TTI having a time length of 1 ms may be called a regular TTI (TTI in 3GPP Rel. 8-12), normal TTI, long TTI, regular subframe, normal subframe, long subframe, slot, etc. A TTI shorter than a regular TTI may be called a shortened TTI, short TTI, partial or fractional TTI, shortened subframe, short subframe, minislot, subslot, slot, etc.

[0304] In addition, a long TTI (e.g., a normal TTI, a subframe, etc.) may be interpreted as a TTI having a time length of more than 1 ms, and a short TTI (e.g., a shortened TTI, etc.) may be interpreted as a TTI having a TTI length shorter than the TTI length of a long TTI and greater than or equal to 1 ms.

[0305] A resource block (RB) is a resource allocation unit in the time domain and the frequency domain, and may include one or more consecutive subcarriers in the frequency domain. The number of subcarriers included in an RB may be the same regardless of numerology, for example, 12. The number of subcarriers included in an RB may be determined based on numerology.

[0306] In addition, an RB may include one or more symbols in the time domain and may have a length of one slot, one minislot, one subframe, or one TTI, each of which may be composed of one or more resource blocks.

[0307] In addition, one or more RBs may be referred to as a physical resource block (PRB), a sub-carrier group (SCG), a resource element group (REG), a PRB pair, an RB pair, etc.

[0308] 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.

[0309] A Bandwidth Part (BWP), which may also be referred to as a partial bandwidth, may represent a subset of contiguous common resource blocks (RBs) for a given numerology on a given carrier, where the common RBs may be identified by their index relative to a Common Reference Point of the carrier. PRBs may be defined in a BWP and numbered within the BWP.

[0310] The BWP may include a UL BWP (BWP for UL) and a DL BWP (BWP for DL). One or more BWPs may be configured for a UE within one carrier.

[0311] 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."

[0312] 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.

[0313] Furthermore, the information, parameters, etc. described in the present disclosure may be expressed using absolute values, may be expressed using relative values ​​from a predetermined value, or may be expressed using other corresponding information. For example, a radio resource may be indicated by a predetermined index.

[0314] The names used for parameters and the like in this disclosure are not intended to be limiting in any way. Furthermore, the mathematical expressions and the like using these parameters may differ from those explicitly disclosed in this disclosure. The various channels (PUCCH, PDCCH, etc.) and information elements may be identified by any suitable names, and therefore the various names assigned to these various channels and information elements are not intended to be limiting in any way.

[0315] 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.

[0316] Furthermore, information, signals, etc. may be output from a higher layer to a lower layer and / or from a lower layer to a higher layer. Information, signals, etc. may be input / output via multiple network nodes.

[0317] Input and output information, signals, etc. may be stored in a specific location (for example, memory) or may be managed using a management table. Input and output information, signals, etc. may be overwritten, updated, or added. Output information, signals, etc. may be deleted. Input information, signals, etc. may be transmitted to another device.

[0318] With respect to any information (e.g., variables, constants, parameters) described in the present disclosure, even if not specifically stated in the above embodiments, any first device (e.g., UE / base station) may notify any second device (e.g., base station / UE) of information indicating / specifying (or relating to) the value of the any information.

[0319] The notification of information is not limited to the aspects / embodiments described in the present disclosure, and may be performed using other methods. For example, the notification of information in the present disclosure may be performed by physical layer signaling (e.g., Downlink Control Information (DCI) and Uplink Control Information (UCI)), higher layer signaling (e.g., Radio Resource Control (RRC) signaling, broadcast information (Master Information Block (MIB) and System Information Block (SIB)), Medium Access Control (MAC) signaling), other signals, or a combination thereof.

[0320] Note that the physical layer signaling may be referred to as Layer 1 / Layer 2 (L1 / L2) control information (L1 / L2 control signal), L1 control information (L1 control signal), etc. Furthermore, the RRC signaling may be referred to as an RRC message, such as an RRC Connection Setup message or an RRC Connection Reconfiguration message. Furthermore, the MAC signaling may be notified using, for example, a MAC Control Element (CE).

[0321] Furthermore, notification of specified information (e.g., notification that "it is X") is not limited to explicit notification, but may be made implicitly (e.g., by not notifying the specified information or by notifying other information).

[0322] The determination may be made by a value represented by one bit (0 or 1), by a Boolean value represented by true or false, or by a comparison of numerical values ​​(e.g., comparison with a predetermined value).

[0323] 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.

[0324] Software, instructions, information, etc. may also be transmitted or received over a transmission medium. For example, if software is transmitted from a website, server, or other remote source using wired technologies (such as coaxial cable, fiber optic cable, twisted pair, Digital Subscriber Line (DSL)), and / or wireless technologies (such as infrared, microwave), these wired and / or wireless technologies are included within the definition of transmission media.

[0325] As used in this disclosure, the terms "system" and "network" may be used interchangeably. A "network" may refer to devices included in the network (e.g., base stations).

[0326] In this disclosure, terms such as "precoding," "precoder," "weight (precoding weight)," "Quasi-Co-Location (QCL)," "Transmission Configuration Indication state (TCI state)," "spatial relation," "spatial domain filter," "transmit power," "phase rotation," "antenna port," "layer," "number of layers," "rank," "resource," "resource set," "beam," "beam width," "beam angle," "antenna," "antenna element," "panel," "UE panel," "transmitting entity," "receiving entity," etc. may be used interchangeably.

[0327] In the present disclosure, the term "antenna port" may be interchangeably read as an antenna port for any signal / channel (e.g., a demodulation reference signal (DMRS) port). In the present disclosure, the term "resource" may be interchangeably read as a resource for any signal / channel (e.g., a reference signal resource, an SRS resource, etc.). The resource may include time / frequency / code / space / power resources. Furthermore, the spatial domain transmission filter may include at least one of a spatial domain transmission filter and a spatial domain reception filter.

[0328] The group may include, for example, at least one of a spatial relationship group, a Code Division Multiplexing (CDM) group, a Reference Signal (RS) group, a Control Resource Set (CORESET) group, a PUCCH group, an antenna port group (e.g., a DMRS port group), a layer group, a resource group, a beam group, an antenna group, a panel group, and the like.

[0329] In addition, in the present disclosure, beam, SRS Resource Indicator (SRI), CORESET, CORESET pool, PDSCH, PUSCH, codeword (CW), transport block (TB), RS, etc. may be read as interchangeable terms.

[0330] In addition, in the present disclosure, the terms TCI state, downlink TCI state (DL TCI state), uplink TCI state (UL TCI state), unified TCI state, common TCI state, joint TCI state, etc. may be read interchangeably.

[0331] Furthermore, in the present disclosure, terms such as "QCL," "QCL assumption," "QCL relationship," "QCL type information," "QCL property / properties," "specific QCL type (e.g., Type A, Type D) property," and "specific QCL type (e.g., Type A, Type D)" may be interchangeable.

[0332] In the present disclosure, terms such as index, identifier (ID), indicator, indication, and resource ID may be interchangeable. In the present disclosure, terms such as sequence, list, set, group, cluster, and subset may be interchangeable.

[0333] Furthermore, the spatial relationship information identifier (ID) (TCI state ID) and the spatial relationship information (TCI state) may be interchangeable. The "spatial relationship information (TCI state)" may be interchangeable with "set of spatial relationship information (TCI state)", "one or more pieces of spatial relationship information", etc. The TCI state and the TCI may be interchangeable. The spatial relationship information and the spatial relationship may be interchangeable.

[0334] In the present disclosure, terms such as "base station (BS)," "radio base station," "fixed station," "NodeB," "eNB (eNodeB)," "gNB (gNodeB)," "access point," "transmission point (TP)," "reception point (RP)," "transmission / reception point (TRP)," "panel," "cell," "sector," "cell group," "carrier," "component carrier," etc. may be used interchangeably. Base stations may also be referred to by terms such as macrocell, small cell, femtocell, picocell, etc.

[0335] A base station can accommodate one or more (e.g., three) cells. When a base station accommodates multiple cells, the overall coverage area of ​​the base station can be partitioned into multiple smaller areas, and each smaller area can be provided with communication service by a base station subsystem (e.g., a small indoor base station (Remote Radio Head (RRH))). The terms "cell" or "sector" refer to part or all of the coverage area of ​​a base station and / or base station subsystem that provides communication service within that coverage.

[0336] In the present disclosure, a base station transmitting information to a terminal may be interpreted as the base station instructing the terminal to control / operate based on the information.

[0337] In this disclosure, the terms "Mobile Station (MS)," "user terminal," "User Equipment (UE)," "terminal," etc. may be used interchangeably.

[0338] A mobile station may also be referred to as a subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, handset, user agent, mobile client, client, or some other suitable terminology.

[0339] At least one of the base station and the mobile station may be called a transmitting device, a receiving device, a wireless communication device, etc. Note that at least one of the base station and the mobile station may be a device mounted on a moving object, the moving object itself, etc.

[0340] The mobile body is a movable object that can move at any speed and naturally includes cases where the mobile body is stationary. Examples of the mobile body include, but are not limited to, vehicles, transport vehicles, automobiles, motorcycles, bicycles, connected cars, excavators, bulldozers, wheel loaders, dump trucks, forklifts, trains, buses, handcars, rickshaws, ships and other watercraft, airplanes, rockets, satellites, drones, multicopters, quadcopters, balloons, and objects mounted thereon. The mobile body may also be a mobile body that moves autonomously based on an operation command.

[0341] The mobile object may be a vehicle (e.g., a car, an airplane, etc.), an unmanned mobile object (e.g., a drone, an autonomous vehicle, etc.), or a robot (manned or unmanned). Note that at least one of the base station and the mobile station may also include devices that do not necessarily move during communication operations. For example, at least one of the base station and the mobile station may be an Internet of Things (IoT) device such as a sensor.

[0342] 10 is a diagram showing an example of a vehicle according to an embodiment. The vehicle 40 includes a drive unit 41, a steering unit 42, an accelerator pedal 43, a brake pedal 44, a shift lever 45, left and right front wheels 46, left and right rear wheels 47, axles 48, an electronic control unit 49, various sensors (including a current sensor 50, an RPM sensor 51, an air pressure sensor 52, a vehicle speed sensor 53, an acceleration sensor 54, an accelerator pedal sensor 55, a brake pedal sensor 56, a shift lever sensor 57, and an object detection sensor 58), an information service unit 59, and a communication module 60.

[0343] The drive unit 41 is configured with at least one of an engine, a motor, and a hybrid of an engine and a motor, for example. The steering unit 42 includes at least a steering wheel (also called a handle) and is configured to steer at least one of the front wheels 46 and the rear wheels 47 based on the operation of the steering wheel operated by a user.

[0344] The electronic control unit 49 is composed of a microprocessor 61, memory (ROM, RAM) 62, and a communication port (for example, an input / output (IO) port) 63. Signals are input to the electronic control unit 49 from various sensors 50-58 provided in the vehicle. The electronic control unit 49 may also be called an Electronic Control Unit (ECU).

[0345] The signals from the various sensors 50-58 include a current signal from a current sensor 50 that senses the current of the motor, a rotation speed signal of the front wheels 46 / rear wheels 47 obtained by a rotation speed sensor 51, an air pressure signal of the front wheels 46 / rear wheels 47 obtained by an air pressure sensor 52, a vehicle speed signal obtained by a vehicle speed sensor 53, an acceleration signal obtained by an acceleration sensor 54, a depression amount signal of the accelerator pedal 43 obtained by an accelerator pedal sensor 55, a depression amount signal of the brake pedal 44 obtained by a brake pedal sensor 56, an operation signal of the shift lever 45 obtained by a shift lever sensor 57, and a detection signal for detecting obstacles, vehicles, pedestrians, etc. obtained by an object detection sensor 58.

[0346] The information service unit 59 is composed of various devices, such as a car navigation system, an audio system, speakers, a display, a television, and a radio, for providing (outputting) various information such as driving information, traffic information, and entertainment information, and one or more ECUs for controlling these devices. The information service unit 59 uses information acquired from external devices via the communication module 60 or the like to provide various information / services (e.g., multimedia information / multimedia services) to the occupants of the vehicle 40.

[0347] The information service unit 59 may include input devices (e.g., keyboards, mice, microphones, switches, buttons, sensors, touch panels, etc.) that accept input from the outside, and may also include output devices (e.g., displays, speakers, LED lamps, touch panels, etc.) that output to the outside.

[0348] The driving assistance system unit 64 includes various devices for providing functions to prevent accidents and reduce the driver's driving burden, such as millimeter-wave radar, Light Detection and Ranging (LiDAR), cameras, positioning locators (e.g., Global Navigation Satellite System (GNSS)), map information (e.g., High Definition (HD) maps, Autonomous Vehicle (AV) maps), gyro systems (e.g., Inertial Measurement Units (IMUs), Inertial Navigation Systems (INSs)), artificial intelligence (AI) chips, and AI processors, as well as one or more ECUs that control these devices. The driving assistance system unit 64 also transmits and receives various information via the communication module 60 to realize driving assistance functions or autonomous driving functions.

[0349] The communication module 60 can communicate with the microprocessor 61 and components of the vehicle 40 via the communication port 63. For example, the communication module 60 transmits and receives data (information) via the communication port 63 to and from the drive unit 41, steering unit 42, accelerator pedal 43, brake pedal 44, shift lever 45, left and right front wheels 46, left and right rear wheels 47, axles 48, the microprocessor 61 and memory (ROM, RAM) 62 in the electronic control unit 49, and the various sensors 50-58, which are provided in the vehicle 40.

[0350] The communication module 60 is a communication device that can be controlled by the microprocessor 61 of the electronic control unit 49 and can communicate with an external device. For example, it transmits and receives various information to and from the external device via wireless communication. The communication module 60 may be located either inside or outside the electronic control unit 49. The external device may be, for example, the base station 10 or the user terminal 20 described above. Furthermore, the communication module 60 may be, for example, at least one of the base station 10 and the user terminal 20 described above (or may function as at least one of the base station 10 and the user terminal 20).

[0351] The communication module 60 may transmit at least one of signals from the above-mentioned various sensors 50-58 input to the electronic control unit 49, information obtained based on the signals, and information based on input from the outside (user) obtained via the information service unit 59 to an external device via wireless communication. The electronic control unit 49, the various sensors 50-58, the information service unit 59, etc. may be referred to as input units that accept input. For example, the PUSCH transmitted by the communication module 60 may include information based on the above-mentioned input.

[0352] The communication module 60 receives various information (traffic information, traffic signal information, vehicle distance information, etc.) transmitted from an external device and displays it on an information service unit 59 provided in the vehicle. The information service unit 59 may also be called an output unit that outputs information (for example, outputs information to a device such as a display or speaker based on the PDSCH received by the communication module 60 (or data / information decoded from the PDSCH)).

[0353] Furthermore, the communication module 60 stores various information received from external devices in a memory 62 that can be used by the microprocessor 61. Based on the information stored in the memory 62, the microprocessor 61 may control the drive unit 41, steering unit 42, accelerator pedal 43, brake pedal 44, shift lever 45, left and right front wheels 46, left and right rear wheels 47, axles 48, various sensors 50-58, and the like provided in the vehicle 40.

[0354] Furthermore, a base station in the present disclosure may be read as a user terminal. For example, the aspects / embodiments of the present disclosure may be applied to a configuration in which communication between a base station and a user terminal is replaced with communication between multiple user terminals (which may be called, for example, Device-to-Device (D2D) or Vehicle-to-Everything (V2X)). In this case, the user terminal 20 may be configured to have the functions of the base station 10 described above. Furthermore, terms such as "uplink" and "downlink" may be read as terms corresponding to terminal-to-terminal communication (for example, "sidelink"). For example, terms such as an uplink channel and a downlink channel may be read as a sidelink channel.

[0355] Similarly, the user terminal in the present disclosure may be read as a base station, in which case the base station 10 may be configured to have the functions of the user terminal 20 described above.

[0356] In the present disclosure, an operation described as being performed by a base station may be performed by its upper node in some cases. It is apparent that in a network including one or more network nodes having a base station, various operations performed for communication with a terminal may be performed by the base station, one or more network nodes other than the base station (such as, but not limited to, a Mobility Management Entity (MME), a Serving-Gateway (S-GW), etc.), or a combination thereof.

[0357] Each aspect / embodiment described in this disclosure may be used alone, in combination, or switched depending on the implementation. Furthermore, the order of the processing procedures, sequences, flowcharts, etc. of each aspect / embodiment described in this disclosure may be changed unless inconsistent. For example, the methods described in this disclosure present elements of various steps using an example order, and are not limited to the particular order presented.

[0358] Each aspect / embodiment described in the present disclosure may be a technology other than Long Term Evolution (LTE), LTE-Advanced (LTE-A), LTE-Beyond (LTE-B), SUPER 3G, IMT-Advanced, 4th generation mobile communication system (4G), 5th generation mobile communication system (5G), 6th generation mobile communication system (6G), xth generation mobile communication system (xG (x is, for example, an integer or decimal number)), Future Radio Access (FRA), New-Radio Access Technology (RAT), New Radio (NR), New radio access (NX), Future generation radio access (FX), Global System for Mobile communications (GSM (registered trademark)), CDMA2000, Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE 802.17 (WiMAX (registered trademark)), IEEE 802.19 (WiMAX (registered trademark)), IEEE 802.20 (WiMAX (registered trademark)), IEEE 802.21 (Wi-Fi (registered trademark)), IEEE 802.22 (WiMAX (registered trademark)), IEEE 802.23 (WiMAX (registered trademark)), IEEE 802.24 (WiMAX (registered trademark)), IEEE 802.25 (WiMAX (registered trademark)), IEEE 802.26 (WiMAX (registered trademark)), IEEE 802.27 (WiMAX (registered trademark)), IEEE 802.28 (WiMAX (registered trademark)), IEEE 802.29 (WiMAX (registered trademark)), IEEE 802.30 (WiMAX (registered trademark)), IEEE 802.31 (Wi-Fi (registered trademark)), IEEE 802.32 (WiMAX (registered trademark)), IEEE 802.33 (WiMAX (registered trademark)), IEEE 802. The present invention may be applied to systems that use IEEE 802.20, Ultra-WideBand (UWB), Bluetooth (registered trademark), or other suitable wireless communication methods, or to next-generation systems that are expanded, modified, created, or defined based on these. Furthermore, the present invention may be applied to a combination of multiple systems (e.g., a combination of LTE or LTE-A and 5G).

[0359] 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."

[0360] 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.

[0361] The term "determining" as used in this disclosure may encompass a wide variety of actions. For example, "determining" may be considered to be judging, calculating, computing, processing, deriving, investigating, looking up, search, inquiry (e.g., looking up in a table, database, or another data structure), ascertaining, etc.

[0362] Additionally, "determining" may be considered to be "determining" receiving (e.g., receiving information), transmitting (e.g., sending information), input, output, accessing (e.g., accessing data in memory), etc.

[0363] Furthermore, "determination" may be considered to be "determining" resolving, selecting, choosing, establishing, comparing, etc. In other words, "determination" may be considered to be "determining" some kind of action. In the present disclosure, "determination" may be read interchangeably with the above-mentioned actions.

[0364] Furthermore, in this disclosure, "determine / determining" may be interchangeably read as "assume / assuming," "expect / expecting," "consider / considering," etc. Furthermore, in this disclosure, "does not expect to do..." may be interchangeably read as "assumes not to do...."

[0365] In the present disclosure, "expect" may be interchangeably read as "be expected." For example, "expect(s) ..." ("..." may be expressed, for example, as a that clause, a to-infinitive, etc.) may be interchangeably read as "be expected ..." or "do ... (if the above "..." is a to-infinitive, a verb with "to")," etc. "does not expect ..." may be interchangeably read as "be not expected ..." or "does not ... (if the above "..." is a to-infinitive, a verb with "to")," etc. Furthermore, "An apparatus A is not expected ..." may be interchangeably read as "an apparatus B other than apparatus A does not expect ... from apparatus A" (for example, if apparatus A is a UE, apparatus B may be a base station).

[0366] 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.

[0367] As used in this disclosure, the terms "connected," "coupled," or any variation thereof, refer to any direct or indirect connection or coupling between two or more elements, and may include the presence of one or more intermediate elements between two elements that are "connected" or "coupled" to each other. The coupling or connection between elements may be physical, logical, or a combination thereof. For example, "connected" may be read as "access."

[0368] In this disclosure, when two elements are connected, they may be considered to be "connected" or "coupled" to one another using one or more wires, cables, printed electrical connections, etc., as well as using electromagnetic energy having wavelengths in the radio frequency range, microwave range, light (both visible and invisible) range, etc., as some non-limiting and non-exhaustive examples.

[0369] 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."

[0370] When the terms "include," "including," and variations thereof are used in this disclosure, these terms are intended to be inclusive, similar to the term "comprising." Furthermore, when the term "or" is used in this disclosure, it is not intended to be an exclusive or.

[0371] 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.

[0372] In the present disclosure, terms such as "less than or equal to," "less than," "greater than," "more than," "equal to," etc. may be interchangeable. Furthermore, in the present disclosure, terms meaning "good," "bad," "big," "small," "high," "low," "fast," "slow," "wide," "narrow," etc. may be interchangeable, not limited to the positive, comparative, and superlative. Furthermore, in the present disclosure, terms meaning "good," "bad," "big," "small," "high," "low," "fast," "slow," "wide," "narrow," etc. may be interchangeable, not limited to the positive, comparative, and superlative, as expressions with "i-th" (i is an arbitrary integer) attached (for example, "highest" may be interchangeable with "i-th highest").

[0373] In this disclosure, the terms "of," "for," "regarding," "related to," "associated with," etc. may be read interchangeably.

[0374] In the present disclosure, terms such as "when A, B," "if A, (then) B," "B upon A," "B in response to A," "B based on A," "B during / while A," "B before A," "B at (the same time as) / on A," "B after A," "B since A," and "B until A" may be interchangeable. Note that A, B, and the like herein may be replaced with appropriate expressions such as nouns, gerunds, and regular sentences, depending on the context. Note that the time difference between A and B may be approximately zero (immediately after or immediately before). A time offset may also be applied to the time at which A occurs. For example, "A" may be interchangeable with "before / after a time offset at which A occurs." The time offset (eg, one or more symbols / slots) may be predefined or may be specified by the UE based on signaled information.

[0375] In the present disclosure, timing, time, duration, time instance, any time unit (e.g., slot, subslot, symbol, subframe), period, occasion, resource, etc. may be read interchangeably.

[0376] Although the invention according to the present disclosure has been described in detail above, it is clear to those skilled in the art that the invention according to the present disclosure is not limited to the embodiments described in the present disclosure. The description of the present disclosure is for illustrative purposes only and does not impose any limiting meaning on the invention according to the present disclosure.

Claims

1. A terminal having: a transmitting unit that transmits a first message regarding an initial access procedure for a plurality of cells to at least one of the plurality of cells; and a control unit that controls reception of a second message transmitted from at least one of the plurality of cells in response to the first message.

2. The terminal of claim 1, wherein the first message includes information about a resource that receives the second message.

3. The terminal according to claim 1, wherein the control unit controls the transmission of the first message based on at least one of a specific setting and a specific condition.

4. The terminal according to claim 1, wherein the transmitting unit transmits the first message to at least two of the plurality of cells.

5. A wireless communication method for a terminal, comprising: a step of transmitting a first message related to an initial access procedure for a plurality of cells to at least one of the plurality of cells; and a step of controlling reception of a second message transmitted from at least one of the plurality of cells in response to the first message.

6. A base station comprising: a receiver that receives a first message related to an initial access procedure, the first message being transmitted to at least two of a plurality of cells; and a controller that controls transmission of a second message in response to the first message.

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