Method and apparatus for initial access in multi-beam communication system

Abstract

This method of a terminal may comprise the steps of: performing a synchronization signal block (SSB) reception operation of receiving SSBs from a base station; determining a first SSB resource and a second SSB resource on the basis of the SSB reception operation; transmitting, to the base station, a first preamble in a first physical random access channel (PRACH) resource corresponding to the first SSB resource; and transmitting, to the base station, information about the second SSB resource through a first uplink (UL) resource.

Description

Method and apparatus for initial connection in a multi-beam communication system

[0001] The present invention relates to a multi-beam communication system, and more specifically, to a method for a terminal to perform an initial connection to a base station by utilizing a plurality of beams, and an apparatus for the same.

[0002] The importance of developing next-generation communication systems (e.g., NR (new radio) communication systems, 6G (sixth generation) communication systems, etc.) as infrastructure for the expansion of various future convergence services is growing. Next-generation communication systems can support not only conventional mobile communication frequency bands but also millimeter wave bands, terahertz bands, and upper-mid bands. Next-generation communication systems can support a wider range of performance indicators and scenarios than conventional communication systems (e.g., LTE (long term evolution) communication systems). In communication using high-frequency bands, technologies for stably managing terminal beams may be required to support beamforming-based transmission, and performance improvement technologies utilizing multiple beams may be required.

[0003] The purpose of the present disclosure to solve the above-mentioned problems is to provide a method for a terminal to perform an initial connection to a base station by utilizing a plurality of beams in a multi-beam communication system, and an apparatus for the same.

[0004] A method of a terminal according to embodiments of the present disclosure for achieving the above objective may include: performing an SSB receiving operation of receiving SSB (synchronization signal blocks) from a base station; determining a first SSB resource and a second SSB resource based on the SSB receiving operation; transmitting a first preamble from a first PRACH (physical random access channel) resource corresponding to the first SSB resource to the base station; and transmitting information about the second SSB resource to the base station through a first uplink (UL) resource.

[0005] The above method may further include the step of receiving from the base station a first instruction information indicating the first UL resource and / or a second instruction information indicating to transmit information about the second SSB resource through the first UL resource.

[0006] The first instruction information and / or the second instruction information can be received from the base station through downlink control information (DCI).

[0007] The above first instruction information and / or the above second instruction information may be generated at the MAC (medium access control) layer or RRC (radio resource control) layer of the base station and received from the base station via the PDSCH (physical downlink shared channel).

[0008] The above-mentioned first UL resource may be a PUCCH (physical uplink control channel) resource.

[0009] The first UL resource may be a PUSCH (physical uplink shared channel) resource indicated by a RAR (random access response) grant received from the base station within a random access (RA) procedure for the base station, or a PUSCH resource transmitted after receiving a Msg4 (message 4) PDSCH according to the RA procedure.

[0010] The above method may additionally include a step of transmitting information indicating the existence of information regarding the second SSB resource to the base station prior to the step of transmitting information regarding the second SSB resource to the base station.

[0011] Information indicating the existence of information regarding the second SSB resource can be transmitted to the base station via Msg3(message 3) PUSCH within the RA procedure for the base station.

[0012] The step of transmitting information about the second SSB resource to the base station can be performed when the reception quality of the SSB received through the second SSB resource satisfies a reference value.

[0013] A method of a base station according to embodiments of the present disclosure for achieving the above objective may include: transmitting synchronization signal blocks (SSBs); receiving a first preamble from a terminal in a first physical random access channel (PRACH) resource corresponding to a first SSB resource determined based on the SSBs; and receiving information about a second SSB resource determined based on the SSBs from the terminal through a first uplink (UL) resource.

[0014] The above method may further include the step of transmitting to the terminal: a first instruction information indicating the first UL resource and / or a second instruction information indicating to transmit information about the second SSB resource through the first UL resource.

[0015] The above first instruction information and / or the above second instruction information may be transmitted to the terminal via downlink control information (DCI).

[0016] The above first instruction information and / or the above second instruction information may be generated at the MAC (medium access control) layer or RRC (radio resource control) layer of the base station and transmitted to the terminal via the PDSCH (physical downlink shared channel).

[0017] The above-mentioned first UL resource may be a PUCCH (physical uplink control channel) resource.

[0018] The first UL resource may be a PUSCH (physical uplink shared channel) resource indicated by a RAR (random access response) grant transmitted to the terminal within a random access (RA) procedure performed with the terminal, or a PUSCH resource received after the transmission of Msg4 (message 4) PDSCH according to the RA procedure.

[0019] The above method may additionally include a step of receiving information from the terminal indicating whether information regarding the second SSB resource exists, prior to the step of receiving information regarding the second SSB resource from the terminal.

[0020] Information indicating whether there is information about the second SSB resource can be received from the terminal via Msg3(message 3) PUSCH within the RA procedure performed with the terminal.

[0021] Information regarding the second SSB resource can be received when the reception quality of the SSB received through the second SSB resource at the terminal satisfies a reference value.

[0022] A terminal according to embodiments of the present disclosure for achieving the above objective comprises at least one processor, and the at least one processor may enable the terminal to perform: a step of performing an SSB receiving operation of receiving SSBs (synchronization signal blocks) from a base station; a step of determining a first SSB resource and a second SSB resource based on the SSB receiving operation; a step of transmitting a first preamble from a first PRACH (physical random access channel) resource corresponding to the first SSB resource to the base station; and a step of transmitting information about the second SSB resource to the base station through a first uplink (UL) resource.

[0023] The first UL resource may be a PUSCH (physical uplink shared channel) resource indicated by a RAR (random access response) grant received from the base station within a random access (RA) procedure for the base station, or a PUSCH resource transmitted after receiving a Msg4 (message 4) PDSCH according to the RA procedure.

[0024] According to the present disclosure as described above, a terminal can report information about a plurality of beams based on SSBs transmitted by a base station. The information about the plurality of beams may be performed within a single random access (RA) procedure or multiple RA procedures performed by the terminal with the base station. Accordingly, in a communication system using multiple beams, the initial connection of the terminal and beam management for the terminal can be performed more efficiently.

[0025] FIG. 1 is a conceptual diagram illustrating embodiments of a communication system.

[0026] FIG. 2 is a block diagram illustrating embodiments of the device.

[0027] FIG. 3 is a conceptual diagram illustrating a first embodiment of an initial connection method based on mutual coupling between DL resources and UL resources.

[0028] FIG. 4 is a conceptual diagram illustrating a first embodiment of a method for reporting a plurality of initial beams based on (method 100).

[0029] FIG. 5 is a conceptual diagram illustrating a second embodiment of a method for reporting a plurality of initial beams based on (method 100).

[0030] FIG. 6 is a conceptual diagram illustrating a third embodiment of a method for reporting a plurality of initial beams based on (method 100).

[0031] FIG. 7 is a conceptual diagram illustrating a first embodiment of a method for reporting a plurality of initial beams based on (method 200).

[0032] FIG. 8 is a conceptual diagram illustrating a second embodiment of a method for reporting a plurality of initial beams based on (method 200).

[0033] The present disclosure is capable of various modifications and may have various embodiments, and specific embodiments are illustrated in the drawings and described in detail. However, this is not intended to limit the present disclosure to specific embodiments, and it should be understood that it includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the present disclosure.

[0034] Terms such as "first," "second," etc., may be used to describe various components, but said components should not be limited by said terms. Such terms are used solely for the purpose of distinguishing one component from another. For example, without departing from the scope of the present disclosure, the first component may be named the second component, and similarly, the second component may be named the first component. The term "and / or" includes a combination of a plurality of related described items or any of a plurality of related described items.

[0035] In embodiments of the present disclosure, "at least one of A and B" may mean "at least one of A or B" or "at least one of one or more combinations of A and B". Additionally, in embodiments of the present disclosure, "at least one of A and B" may mean "at least one of A or B" or "at least one of one or more combinations of A and B".

[0036] When it is stated that one component is "connected" or "connected" to another component, it should be understood that while it may be directly connected or connected to that other component, there may also be other components in between. On the other hand, when it is stated that one component is "directly connected" or "directly connected" to another component, it should be understood that there are no other components in between.

[0037] The terms used in this disclosure are used merely to describe specific embodiments and are not intended to limit this disclosure. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this disclosure, terms such as “comprising” or “having” are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0038] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which this disclosure pertains. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this disclosure.

[0039] Hereinafter, preferred embodiments of the present disclosure will be described in more detail with reference to the attached drawings. In order to facilitate an overall understanding of the present disclosure, the same reference numerals are used for identical components in the drawings, and redundant descriptions of identical components are omitted.

[0040] A communication system to which embodiments according to the present disclosure are applied will be described. The communication system may be a 4G communication system (e.g., LTE (long-term evolution) communication system, LTE-A communication system), a 5G communication system (e.g., NR (new radio) communication system), a 6G communication system, etc. A 4G communication system may support communication in a frequency band of 6 GHz or lower, and a 5G communication system may support communication in a frequency band of 6 GHz or higher as well as in a frequency band of 6 GHz or lower. The communication system to which embodiments according to the present disclosure are applied is not limited to those described below, and embodiments according to the present disclosure may be applied to various communication systems. Here, "communication system" may be used with the same meaning as "communication network," "LTE" may refer to a "4G communication system," an "LTE communication system," or an "LTE-A communication system," and "NR" may refer to a "5G communication system" or an "NR communication system."

[0041] In an embodiment, "an operation (e.g., a transmission operation) being set in a communication node" may mean that "setting information for said operation (e.g., an information element, a parameter)" and / or "information directing the execution of said operation" is signaled to said communication node. In other words, "an operation (e.g., a transmission operation) being set in a communication node" may mean that said communication node receives "setting information for said operation (e.g., an information element, a parameter)" and / or "information directing the execution of said operation." "An information element (e.g., a parameter) being set in a communication node" may mean that said information element is signaled to said communication node (e.g., said communication node receiving said information element). The signaling may be at least one of SI (system information) signaling (e.g., transmission of SIB (system information block) and / or MIB (master information block)), RRC signaling (e.g., transmission of RRC parameters and / or upper layer parameters), MAC CE (control element) signaling, or PHY signaling (e.g., transmission of DCI (downlink control information), UCI (uplink control information), and / or SCI (sidelink control information).

[0042] In the present disclosure, "time" may mean a time point, and "time point" may mean time. Time and time point may be used interchangeably. The reception time of a signal or channel may mean a reception start time or a reception end time. The transmission time of a signal or channel may mean a transmission start time or a transmission end time.

[0043] FIG. 1 is a conceptual diagram illustrating embodiments of a communication system.

[0044] Referring to FIG. 1, the communication system (100) may include a plurality of communication nodes (110-1, 110-2, 110-3, 120-1, 120-2, 130-1, 130-2, 130-3, 130-4, 130-5, 130-6). Additionally, the communication system (100) may further include a core network (e.g., an S-GW (serving-gateway), a P-GW (PDN (packet data network)-gateway), and an MME (mobility management entity)). If the communication system (100) is a 5G communication system (e.g., a new radio (NR) system), the core network may include an AMF (access and mobility management function), a UPF (user plane function), an SMF (session management function), etc.

[0045] Multiple communication nodes (110 to 130) can support communication protocols defined in 3GPP (3rd generation partnership project) standards (e.g., LTE communication protocol, LTE-A communication protocol, NR communication protocol, etc.). Multiple communication nodes (110 to 130) may support CDMA (code division multiple access) technology, WCDMA (wideband CDMA) technology, TDMA (time division multiple access) technology, FDMA (frequency division multiple access) technology, OFDM (orthogonal frequency division multiplexing) technology, Filtered OFDM technology, CP (cyclic prefix)-OFDM technology, DFT-s-OFDM (discrete Fourier transform-spread-OFDM) technology, OFDMA (orthogonal frequency division multiple access) technology, SC (single carrier)-FDMA technology, NOMA (non-orthogonal multiple access) technology, GFDM (generalized frequency division multiplexing) technology, FBMC (filter bank multi-carrier) technology, UFMC (universal filtered multi-carrier) technology, SDMA (space division multiple access) technology, etc. Each of the multiple communication nodes may mean an apparatus or a device. The embodiments may be performed by a device or device. The structure of the device (e.g., device) may be as follows.

[0046] FIG. 2 is a block diagram illustrating embodiments of the device.

[0047] Referring to FIG. 2, the device (200) may include at least one processor (210), a memory (220), and a transceiver (230) that is connected to a network to perform communication. Additionally, the device (200) may further include an input interface device (240), an output interface device (250), a storage device (260), etc. Each component included in the device (200) may be connected by a bus (270) to perform communication with each other.

[0048] The processor (210) can execute a program command stored in at least one of the memory (220) and the storage device (260). The processor (210) may mean a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor on which the methods according to embodiments of the present disclosure are performed. Each of the memory (220) and the storage device (260) may be composed of at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory (220) may be composed of at least one of read-only memory (ROM) and random access memory (RAM).

[0049] Referring again to FIG. 1, the communication system (100) may include a plurality of base stations (110-1, 110-2, 110-3, 120-1, 120-2) and a plurality of terminals (130-1, 130-2, 130-3, 130-4, 130-5, 130-6). Each of the first base station (110-1), the second base station (110-2), and the third base station (110-3) may form a macro cell. Each of the fourth base station (120-1) and the fifth base station (120-2) may form a small cell. The fourth base station (120-1), the third terminal (130-3), and the fourth terminal (130-4) may be located within the cell coverage of the first base station (110-1). The second terminal (130-2), the fourth terminal (130-4), and the fifth terminal (130-5) may be located within the cell coverage of the second base station (110-2). The fifth base station (120-2), the fourth terminal (130-4), the fifth terminal (130-5), and the sixth terminal (130-6) may be located within the cell coverage of the third base station (110-3). The first terminal (130-1) may be located within the cell coverage of the fourth base station (120-1). The sixth terminal (130-6) may be located within the cell coverage of the fifth base station (120-2).

[0050] Here, each of the multiple base stations (110-1, 110-2, 110-3, 120-1, 120-2) may be referred to as NB (NodeB), eNB (evolved NodeB), gNB, ABS (advanced base station), HR-BS (high reliability-base station), BTS (base transceiver station), radio base station, radio transceiver, access point, access node, RAS (radio access station), MMR-BS (mobile multihop relay-base station), RS (relay station), ARS (advanced relay station), HR-RS (high reliability-relay station), HNB (home NodeB), HeNB (home eNodeB), RSU (road side unit), RRH (radio remote head), TP (transmission point), TRP (transmission and reception point), etc.

[0051] Each of the multiple terminals (130-1, 130-2, 130-3, 130-4, 130-5, 130-6) may be referred to as UE (user equipment), TE (terminal equipment), AMS (advanced mobile station), HR-MS (high reliability-mobile station), terminal, access terminal, mobile terminal, station, subscriber station, mobile station, portable subscriber station, node, device, OBU (on board unit), etc.

[0052] Meanwhile, each of the multiple base stations (110-1, 110-2, 110-3, 120-1, 120-2) may operate in different frequency bands or in the same frequency band. Each of the multiple base stations (110-1, 110-2, 110-3, 120-1, 120-2) may be connected to each other via an ideal backhaul link or a non-ideal backhaul link, and may exchange information with each other via an ideal backhaul link or a non-ideal backhaul link. Each of the multiple base stations (110-1, 110-2, 110-3, 120-1, 120-2) may be connected to a core network via an ideal backhaul link or a non-ideal backhaul link. Each of the multiple base stations (110-1, 110-2, 110-3, 120-1, 120-2) can transmit a signal received from the core network to the corresponding terminal (130-1, 130-2, 130-3, 130-4, 130-5, 130-6), and can transmit a signal received from the corresponding terminal (130-1, 130-2, 130-3, 130-4, 130-5, 130-6) to the core network.

[0053] In addition, each of the multiple base stations (110-1, 110-2, 110-3, 120-1, 120-2) can support MIMO transmission (e.g., SU (single user)-MIMO, MU (multi user)-MIMO, massive MIMO, etc.), CoMP (coordinated multipoint) transmission, carrier aggregation (CA) transmission, transmission in an unlicensed band, device-to-device communication (D2D) (or ProSe (proximity services)), IoT (Internet of Things) communication, dual connectivity (DC), etc. Here, each of the plurality of terminals (130-1, 130-2, 130-3, 130-4, 130-5, 130-6) can perform an operation corresponding to the base station (110-1, 110-2, 110-3, 120-1, 120-2) and an operation supported by the base station (110-1, 110-2, 110-3, 120-1, 120-2). For example, the second base station (110-2) can transmit a signal to the fourth terminal (130-4) based on the SU-MIMO method, and the fourth terminal (130-4) can receive a signal from the second base station (110-2) based on the SU-MIMO method. Alternatively, the second base station (110-2) can transmit a signal to the fourth terminal (130-4) and the fifth terminal (130-5) based on the MU-MIMO method, and each of the fourth terminal (130-4) and the fifth terminal (130-5) can receive a signal from the second base station (110-2) by the MU-MIMO method.

[0054] Each of the first base station (110-1), the second base station (110-2), and the third base station (110-3) can transmit a signal to the fourth terminal (130-4) based on the CoMP method, and the fourth terminal (130-4) can receive a signal from the first base station (110-1), the second base station (110-2), and the third base station (110-3) by the CoMP method. Each of the multiple base stations (110-1, 110-2, 110-3, 120-1, 120-2) can transmit and receive signals based on the CA method with terminals (130-1, 130-2, 130-3, 130-4, 130-5, 130-6) within its cell coverage area. Each of the first base station (110-1), the second base station (110-2), and the third base station (110-3) can control D2D between the fourth terminal (130-4) and the fifth terminal (130-5), and each of the fourth terminal (130-4) and the fifth terminal (130-5) can perform D2D by controlling each of the second base station (110-2) and the third base station (110-3).

[0055] The numerology applied to physical signals and channels in a communication system (e.g., NR communication system, 6G communication system) may be variable. The numerology may be variable to meet various technical requirements of the communication system. In a communication system where CP (cyclic prefix) based OFDM waveform technology is applied, the numerology may include subcarrier spacing and CP length (or CP type). Table 1 may be a first embodiment of a numerology configuration for a CP-OFDM based communication system. Adjacent subcarrier spacings may have a relationship of powers of 2 with respect to each other, and the CP length may be scaled at the same ratio as the OFDM symbol length. Depending on the frequency band in which the communication system operates, at least some of the numerologies in Table 1 may be supported. Additionally, numerology(s) not listed in Table 1 may be further supported in the communication system. For a specific subcarrier interval (e.g., 60 kHz), additional CP type(s) not listed in Table 1 (e.g., extended CP) may be supported.

[0056]

[0057]

[0058] Below, the frame structure of a communication system will be described. In the time domain, the elements constituting the frame structure (e.g., resource elements) may include subframes, slots, minislots, symbols, etc. Subframes may be used as units for transmission, measurement, etc., and the length of a subframe may have a fixed value (e.g., 1 ms) regardless of the subcarrier interval. Slots may contain consecutive symbols (e.g., 14 OFDM symbols). Unlike the length of a subframe, the length of a slot may be variable. For example, the length of a slot may be inversely proportional to the subcarrier interval.

[0059] Slots may be used as units for transmission, measurement, scheduling, resource allocation, timing (e.g., scheduling timing, HARQ (hybrid automatic repeat request) timing, CSI (channel state information) measurement and reporting timing, etc.). The length of the actual time resource used for transmission, measurement, scheduling, resource allocation, etc. may or may not match the length of the slot. Mini-slots may contain consecutive symbol(s), and the length of a mini-slot may be shorter than the length of a slot. Mini-slots may be used as units for transmission, measurement, scheduling, resource allocation, timing, etc. Mini-slots (e.g., mini-slot length, mini-slot boundaries, etc.) may be predefined in the technical specifications. Alternatively, mini-slots (e.g., mini-slot length, mini-slot boundaries, etc.) may be configured (or instructed) to the terminal. The use of a mini-slot when specific conditions are satisfied may be configured (or instructed) to the terminal.

[0060] A base station can schedule data channels (e.g., PDSCH (physical downlink shared channel), PUSCH (physical uplink shared channel), PSSCH (physical sidelink shared channel)) using some or all of the symbols constituting a slot. In particular, for Ultra Reliable Low Latency Communication (URLC) transmission, unlicensed band transmission, transmission in a coexistence situation between NR communication systems and LTE communication systems, and analog beamforming-based multi-user scheduling, a data channel may be transmitted using a portion of a slot. Additionally, a base station can schedule data channels using multiple slots. Furthermore, a base station can schedule data channels using at least one mini-slot.

[0061] In the frequency domain, elements constituting the frame structure may include resource blocks (RBs), subcarriers, etc. A single RB may include consecutive subcarriers (e.g., 12 subcarriers). The number of subcarriers constituting a single RB may be constant regardless of the numerator. In this case, the bandwidth occupied by a single RB may be proportional to the subcarrier spacing of the numerator. RBs may be used as units for transmission and resource allocation, such as data channels and control channels. Resource allocation for data channels may be performed at the level of RBs or RB groups (e.g., resource block groups (RBGs)). A single RBG may include one or more consecutive RBs. Resource allocation for control channels may be performed at the level of control channel elements (CCEs). In the frequency domain, a single CCE may include one or more RBs.

[0062] In a communication system (e.g., an NR communication system), the unit time resource described above (hereinafter referred to as a "slot") may be composed of a combination of one or more sections among a DL (downlink) section, a flexible section (or an unknown section), and an UL (uplink) section. Each of the DL section, the flexible section, and the UL section may be composed of one or more consecutive symbols. The flexible section may be located between the DL section and the UL section, between the first DL section and the second DL section, between the first UL section and the second UL section, etc. When a flexible section is inserted between the DL section and the UL section, the flexible section may be used as a protection section.

[0063] A slot may include one or more flexible segments. Alternatively, a slot may not include any flexible segments. A terminal may perform a predefined operation in a flexible segment. Alternatively, a terminal may perform a semi-static or periodically configured operation by a base station in a flexible segment. For example, an operation periodically configured by a base station may include a PDCCH (physical downlink control channel) monitoring operation, an SSB (synchronization signal block) reception and measurement operation, a CSI-RS (reference signal) reception and measurement operation, a DL SPS (semi-persistent scheduling) PDSCH reception operation, an SRS (sounding reference signal) transmission operation, a PRACH (physical random access channel) transmission operation, a periodically configured PUCCH transmission operation, a PUSCH transmission operation according to a configured grant (CG), etc. Flexible symbols may be overridden by DL symbols or UL symbols. When a flexible symbol is overridden by a DL symbol or a UL symbol, the terminal can perform a new operation instead of the existing operation on the flexible symbol (e.g., the overridden flexible symbol).

[0064] In the present disclosure, SSB may mean a set of signals including a synchronization signal and / or a broadcast channel. The synchronization signal may include a primary synchronization signal (PSS), a secondary synchronization signal (SSS), etc., and the broadcast channel may include a physical broadcast channel (PBCH). The SSB may further include a reference signal. The reference signal (e.g., a reference signal included in the SSB) may mean a demodulation reference signal (DM-RS), a CSI-RS, a tracking reference signal (TRS), a positioning reference signal (PRS), a phase tracking reference signal (PT-RS), etc., for decoding the PBCH. In an NR communication system, the SSB may mean an SS / PBCH (synchronization signal / physical broadcast channel) block. The SSB may be transmitted periodically, and one or more SSB(s) may be transmitted repeatedly in one cycle.

[0065] The format of a unit time resource (hereinafter referred to as "slot format") may be semi-fixed by upper-layer signaling (e.g., radio resource control (RRC) signaling). Information indicating the semi-fixed slot format may be included in system information, and the semi-fixed slot format may be set cell-specifically. Additionally, the semi-fixed slot format may be additionally set per terminal through terminal-specific upper-layer signaling (e.g., RRC signaling). The flexible symbols of the slot format set cell-specifically may be overridden by DL symbols or UL symbols by terminal-specific upper-layer signaling. Furthermore, the slot format may be dynamically indicated by physical layer signaling (e.g., slot format indicator (SFI) included in downlink control information (DCI)). The semi-fixed slot format may be overridden by the dynamically indicated slot format. For example, the semi-fixed flexible symbols may be overridden by DL symbols or UL symbols by the SFI.

[0066] A terminal can perform DL operations, UL operations, sidelink operations, etc., in a bandwidth part. A bandwidth part may be defined as a set of consecutive RBs (e.g., physical resource blocks (PRBs)) in a frequency domain having a specific numerator. A single numerator may be used for signal transmission (e.g., transmission of a control channel or a data channel) in a single bandwidth part. In this disclosure, "signal" may mean any physical signal and channel when used in a broad sense. A terminal performing an initial connection procedure may obtain configuration information for an initial bandwidth part from a base station through system information. A terminal operating in an RRC connected state may obtain configuration information for a bandwidth part from a base station through terminal-specific upper layer signaling.

[0067] The configuration information for a bandwidth portion may include information regarding the numeral and / or RB set applied to the bandwidth portion. Among the bandwidth portion(s) configured in the terminal, at least one bandwidth portion may be activated. For example, within a single carrier, one UL bandwidth portion and one DL bandwidth portion may each be activated. In a time division duplex (TDD) based communication system, a pair of UL bandwidth portions and DL bandwidth portions may be activated. A base station may configure multiple bandwidth portions in the terminal within a single carrier and may switch the active bandwidth portion of the terminal.

[0068] In the embodiments, "a certain frequency band (e.g., carrier, bandwidth portion, RB set, LBT (listen before talk) subband, guard band, etc.) is said to be activated" may mean "a state in which a base station or terminal can transmit and receive signals using said frequency band." Additionally, "a certain frequency band is said to be activated" may mean "a state in which the RF (radio frequency) filter of a transceiver (e.g., bandpass filter) operates including said frequency band."

[0069] In the embodiments, RB may refer to a common RB (CRB). Alternatively, RB may refer to a PRB or a virtual RB (VRB). In a communication system (e.g., an NR communication system), a CRB may refer to an RB that constitutes a set of consecutive RBs (e.g., a common RB grid) based on a reference frequency (e.g., point A). A carrier, a bandwidth portion, etc., may be placed on the common RB grid. In other words, the carrier, the bandwidth portion, etc., may be composed of CRB(s). An RB or CRB constituting the bandwidth portion may be referred to as a PRB, and within the bandwidth portion, a CRB index may be appropriately converted to a PRB index. In the embodiments, RB may refer to an interlace RB (IRB).

[0070] A PDCCH can be used to transmit DCI or DCI format to a terminal. The smallest resource unit constituting a PDCCH can be a REG (resource element group). For example, a REG can consist of one RB in the frequency domain and one OFDM symbol in the time domain. DM-RS for decoding the PDCCH can be mapped to some of the REs constituting the REG, and control information (e.g., modulated DCI) can be mapped to the remaining REs. A single PDCCH candidate can consist of one CCE or aggregated CCEs. One CCE can consist of multiple REGs. In an NR communication system, CCE aggregation levels 1, 2, 4, 8, 16, etc., can be supported, and one CCE can consist of six REGs.

[0071] A CORESET (control resource set) may be a resource area where the terminal performs blind decoding of the PDCCH. A CORESET may consist of multiple REGs. A CORESET may consist of one or more RBs in the frequency domain and one or more symbols (e.g., OFDM symbols) in the time domain. The symbols constituting a CORESET may be continuous in the time domain. The RBs constituting a CORESET may be continuous or discontinuous in the frequency domain. A single DCI (e.g., a single DCI format, a single PDCCH) may be transmitted within a single CORESET. Multiple CORESETs may be established from a cell perspective or a terminal perspective, and the time-frequency resource areas to which the multiple CORESETs are mapped may or may not overlap.

[0072] A CORESET can be configured on a terminal during the process of performing an initial connection procedure. For example, a CORESET can be configured on a terminal by an initial connection signal (e.g., PBCH or system information transmitted via PBCH). The ID (identifier) ​​of the CORESET configured by the initial connection signal may be 0. A CORESET configured by the initial connection signal may be referred to as CORESET 0. A terminal operating in an RRC idle state may perform a monitoring operation on CORESET 0 to receive the first PDCCH during the initial connection procedure. Not only terminals operating in an RRC idle state but also terminals operating in an RRC connected state may perform a monitoring operation on CORESET 0. A CORESET can be configured on a terminal by system information other than the system information transmitted via the initial connection signal (e.g., PBCH) (e.g., SIB1 (system information block type 1)). For example, the terminal may receive SIB1 containing configuration information for CORESET for receiving a random access response (e.g., Msg2). CORESET may be configured on the terminal by terminal-specific upper layer signaling (e.g., RRC signaling).

[0073] A search space may refer to a set of candidate resource regions where a PDCCH can be transmitted. A terminal may perform blind decoding on each of the PDCCH candidates within a predefined search space or a search space set by a base station. The terminal may determine whether the PDCCH was transmitted to it by performing a cyclic redundancy check (CRC) on the blind decoding result. If it is determined that the PDCCH is for the terminal, the terminal may receive the PDCCH.

[0074] One or more search space(s) may constitute a search space set. Search spaces may be defined / configured per CCE aggregation level, and a search space set may refer to a search space for each CCE aggregation level or the sum of search spaces for all CCE aggregation levels. For each CCE aggregation level, PDCCH candidates may consist of CCE(s) selected by a predefined hash function within a CORESET or search space occasion. In the embodiments, "search space set" may refer to a "search space".

[0075] A search space set can be logically associated (e.g., combined) with a CORESET. A CORESET can be logically associated with one or more search space sets. A common search space set configured via PBCH can be used to monitor the DCI scheduling the PDSCH for transmitting SIB1. The ID of the common search space set configured via PBCH can be set to 0. In other words, the common search space set configured via PBCH can be defined as Type 0 PDCCH Common Search Space Set or Search Space Set #0. Search Space Set #0 can be logically associated with CORESET 0.

[0076] A search space set may be divided into a common search space set and a UE-specific search space set depending on the purpose or terminal operation. A common DCI or a UE-specific DCI (e.g., a UE-specific DCI) may be transmitted in the common search space set, and a UE-specific DCI may be transmitted in the UE-specific search space set (e.g., a UE-specific search space set). For example, a common DCI may include resource allocation information of a PDSCH including system information and paging messages, power control commands, slot format indicators (SFI), and / or preemption indicators. A UE-specific DCI may include resource allocation information of a PDSCH and / or resource allocation information of a PUSCH. Multiple DCI formats may be defined depending on the purpose, and multiple DCI formats may be distinguished at the terminal by a DCI payload, DCI field, DCI size, and / or a radio network temporary identifier (RNTI).

[0077] In the present disclosure, a common search space may be referred to as a CSS (common search space), and a set of common search spaces may be referred to as a CSS set. A terminal-specific search space may be referred to as a USS (UE-specific search space), and a set of terminal-specific search spaces may be referred to as a USS set.

[0078] The terminal may assume that the PDCCH DM-RS has a quasi-colocation (QCL) relationship with a certain signal (e.g., SSB, CSI-RS, PDSCH DM-RS, PDCCH DM-RS, etc.). The PDCCH DM-RS may refer to the DM-RS used for modulation and / or demodulation of the PDCCH. Since the PDCCH has the same antenna port as the PDCCH DM-RS, the PDCCH and the PDCCH DM-RS may have a QCL relationship with each other. Through the above QCL assumption, the terminal can obtain information regarding the large-scale propagation characteristics of the radio channel experienced by the PDCCH and PDCCH DM-RS, and can utilize these large-scale propagation characteristics for channel estimation, receive beamforming, etc. QCL parameters may include at least one of delay spread, Doppler spread, Doppler shift, average gain, average delay, or spatial Rx parameters. Spatial Rx parameters may correspond to at least one characteristic among a receiving beam, a receiving channel spatial correlation, or a transmit / receive beam pair. Spatial Rx parameters may be referred to as "spatial QCL". PDCCH may be used to mean including PDCCH DM-RS. Saying that PDCCH has a QCL relationship with a certain signal may include the meaning that the DM-RS of said PDCCH has a QCL relationship with said signal. A signal having a QCL relationship with PDCCH or a source of said signal may be referred to as a QCL source, QCL source signal, QCL source resource, etc.

[0079] PDCCHs transmitted from the same CORESET (e.g., a search space set corresponding to the same CORESET, a PDCCH monitoring occupation, etc.) may have the same QCL relationship. In other words, the set unit for which a terminal assumes the same QCL may be a CORESET, and QCL assumptions may be independent for each CORESET. In the embodiment, the QCL and QCL source of a certain CORESET may each refer to the QCL and QCL source of a PDCCH received through that CORESET. Exceptionally, different QCL assumptions may be applied to search space sets corresponding to a single CORESET. For example, a search space set for monitoring RA (random access)-RNTI (e.g., a Type 1 CSS set) and a search space set other than said search space set may have different QCL relationships.

[0080] QCL relationships or QCL assumptions of a CORESET (e.g., QCL source, QCL type, etc.) may be determined by a predefined method. For example, a terminal may assume that a PDCCH DM-RS received through a certain CORESET or a certain search space set has a QCL relationship with a predefined QCL type with respect to an SSB and / or CSI-RS selected during the execution of an initial access or random access procedure. A QCL type may refer to a set of one or more QCL parameters. The QCL relationships or QCL assumptions of a CORESET (e.g., QCL source, QCL type, etc.) may be signaled from the base station to the terminal (e.g., RRC signaling, MAC (medium access control) CE (control element) signaling, DCI signaling, combinations of the above signalings, etc.). In other words, the base station may set a TCI (transmission configuration information) state for the CORESET to the terminal. Generally, a TCI state may include at least one of the ID of a signal (e.g., QCL source of PDCCH DM-RS, QCL source resource) having a QCL relationship with the DM-RS of the physical channel to which the TCI is applied (e.g., PDCCH DM-RS) or the QCL type for said signal. For example, a base station may set one or more TCI state candidates for each CORESET to a terminal via RRC signaling, and may indicate (e.g., set) one TCI state used for monitoring the terminal's CORESET among the one or more TCI state candidates via MAC signaling (or DCI signaling). If there is only one TCI state candidate set by RRC signaling, the MAC signaling procedure (or DCI signaling procedure) may be omitted.The terminal can perform PDCCH monitoring and reception operations for the corresponding CORESET based on TCI status setting information received from the base station.

[0081] In this disclosure, the TCI state may be referred to as TCI for convenience. While TCI may generally refer to a broad concept including a beam or signaling information corresponding to a beam, in this disclosure, it may be used in the sense corresponding to a beam for convenience. A DL TCI or a TCI for receiving a DL signal may correspond to a receiving beam, and a UL TCI or a TCI for transmitting a UL signal may correspond to a transmitting beam. A transmitting beam may refer to spatial relation information, a transmitting spatial filter, etc.

[0082] Meanwhile, beam operation in high-frequency and low-frequency bands may differ in communication systems. In low-frequency bands (e.g., bands below 6 GHz), signal path loss due to the channel is relatively small, so signals can be transmitted and received using beams with a wide beamwidth. Transmission of control channels can cover the entire coverage of a cell (or sector) with a single beam. In high-frequency bands (e.g., bands above 6 GHz), where signal path loss is large, beamforming using large antennas may be used to extend the signal reach. Beamforming can be applied not only to data channels but also to common signal and control channels. A communication node (e.g., a base station) can form a beam with a narrow beamwidth through multiple antennas, and can transmit and receive signals multiple times using multiple beams with different directional orientations to cover the entire spatial area of ​​a cell (or sector). The operation of repeatedly transmitting signals at multiple time resources using multiple beams can be referred to as beam sweeping. A system that transmits signals using multiple beams with narrow beam widths can be referred to as a multi-beam system.

[0083] In a multi-beam system, the beams of a terminal can be managed by a base station. The terminal can measure beam quality for a received signal (e.g., SSB, CSI-RS, etc.) and report the measurement results of the beam quality to the base station. For example, the terminal can calculate beam quality measurements such as RSRP (reference signal received power) (e.g., L1(layer 1)-RSRP) and SINR (signal-to-interference-plus-noise ratio) for each beam (e.g., each signal, each resource) and report the optimal beam(s) and / or the measurement(s) corresponding to said optimal beam(s) to the base station. The terminal can report beam index(s) corresponding to said measurement(s) to the base station. The beam index may refer to information regarding SSB resources, CSI-RS resources, etc. (e.g., SSB resource indicator, CSI-RS resource indicator, etc.). Information regarding the beam index may be included in the CSI, and said CSI may be transmitted via an uplink channel such as PUCCH, PUSCH, etc. The base station may determine the transmission beam for the terminal based on the beam index(s) and / or beam quality measurement information (e.g., beam quality measurement value(s)) reported by the terminal. Based on the beam index(s) and / or beam quality measurement information (e.g., beam quality measurement value(s)) reported by the terminal, the base station may set the TCI state for the terminal for receiving physical signals and channels (e.g., PDCCH, PDSCH, CSI-RS, PUCCH, PUSCH, SRS, PRACH, etc.).

[0084]

[0085] In the embodiments of the present disclosure, unless otherwise noted, “beam” may mean “transmitting beam,” “receiving beam,” and / or “transmitting-receiving beam pair.” Additionally, “beam,” “transmitting beam,” “receiving beam,” “transmitting-receiving beam pair,” etc., may be interchangeable in meaning. Furthermore, “multiple beams” may mean at least one beam(s) as described below.

[0086] In embodiments of the present disclosure, a base station or serving cell may include one or more TRPs, and DL coverage and / or UL coverage may be formed by each TRP. A terminal may perform the operation of receiving a DL signal from each TRP and the operation of transmitting a UL signal to each TRP. Beamforming may be applied to DL reception and UL transmission. The terminal's transmit beam (or transmit space filter) may be generated based on the terminal's receive beam (or receive space filter, beam quality measurement for the received signal). Additionally, the base station or TRP's transmit beam (or transmit space filter) may be generated based on the base station or TRP's receive beam (or receive space filter, beam quality measurement for the received signal). That is, beam correspondence may be established between the transmit beam and the receive beam of a communication node. Hereinafter, for convenience, the statement that a communication node transmits or receives a beam may mean that it transmits or receives a signal to which the beam is applied.

[0087]

[0088] A base station (or TRP) may transmit synchronization signals, broadcast information, etc., to terminal(s) using multiple beams. For example, one or more resources may be defined or configured for the transmission of PSS (primary synchronization signal), SSS (secondary synchronization signal), PBCH, PDCCH, PDSCH, DM-RS, CSI-RS, TRS (tracking reference signal), CRS (cell-specific reference signal), etc., and the signals or channels from said one or more resources may be repeatedly transmitted through beam sweeping operations. Some of said signals may be used as initial connection signals. Additionally, a set of signals including synchronization signals may be transmitted to terminal(s), and this may be referred to as an SSB (synchronization signal block). The signals constituting the SSB may be predefined in technical specifications. In addition to the synchronization signal, the SSB may further include the aforementioned signals (e.g., PBCH, CSI-RS) and may be repeatedly transmitted through beam sweeping operations as described above. In an NR communication system, SSB can mean an SS / PBCH block, and an SSB resource can mean an SS / PBCH block resource.

[0089] The terminal may determine a resource and / or a corresponding beam among the one or more resources for receiving an initial connection signal, and may receive an initial connection signal from the determined resource (based on the determined beam). For example, the terminal may determine a resource having the largest received signal strength measurement of the initial connection signal (e.g., RSRP, L1-RSRP) as the receiving resource, and may determine a beam corresponding to the determined receiving resource as the DL initial beam. The DL initial beam may be a base station's transmission beam. The terminal may receive the initial connection signal and obtain a cell ID (identifier), DL timing, broadcast information, or system information (e.g., MIB (master information block), SIB (system information block)), etc. For example, the initial connection signal may be an SSB.

[0090] The terminal can perform a random access procedure based on the receiving resources and / or beam of the initial connection signal.

[0091] FIG. 3 is a conceptual diagram illustrating a first embodiment of an initial connection method based on mutual coupling between DL resources and UL resources.

[0092] Referring to FIG. 3, DL resource(s) (e.g., DL resource(s) for initial access) and UL resource(s) (e.g., UL resource(s) for random access) can be associated. For example, DL resource(s) can be SSB resource(s). Each DL resource can correspond to DL beams (e.g., transmission beams of a base station). Additionally, UL resource(s) can be PRACH resource(s). Each UL resource can correspond to UL beams (e.g., reception beams of a base station). As described above, the base station can use DL resource(s) to repeatedly transmit an initial access signal through multiple beams. In one embodiment, the terminal can receive an initial connection signal (e.g., SSB, CSI-RS) from DL resource #1 (e.g., SSB resource #1, CSI-RS resource #1), which is one of four DL resources (e.g., SSB resources, CSI-RS resources).

[0093] The terminal may receive the DL resource(s) and the UL resource(s) from the base station, and may receive information regarding the mutual coupling relationship between the UL resource(s) and the DL resource(s). Each UL resource(s) may be mutually coupled with one or more DL resource(s). That is, the DL resource(s) and the UL resource(s) may correspond one-to-one or many-to-one. Alternatively, multiple UL resource(s) may be mutually coupled with a single DL resource. That is, the DL resource(s) and the UL resource(s) may correspond one-to-many. Referring to FIG. 3, the terminal may receive four SSB resources and four PRACH resources. A mutual coupling relationship may be established between the four SSB resources and the four PRACH resources. For example, SSB resources #0, #1, #2, and #3 may be mutually coupled with PRACH resources #0, #1, #2, and #3, respectively.

[0094] The terminal can transmit PRACH from a UL resource coupled with a DL resource that received an initial connection signal (or a DL resource selected during the initial connection process). Referring to FIG. 3, the terminal can transmit PRACH from PRACH resource #1 coupled with a DL resource #1 (e.g., SSB resource #1, CSI-RS resource #1) that received an initial connection signal (e.g., SSB, CSI-RS). In this case, the terminal's PRACH transmission beam can be generated based on the reception beam of the initial connection signal (e.g., SSB, CSI-RS) (i.e., the DL initial beam). Additionally, resources or beams of other UL signals for random access (e.g., Msg3 PUSCH, MsgA PUSCH, PUCCH including a HARQ response message of Msg4, etc.) may be determined based on the DL resources or beams (or UL resources or beams to which the terminal transmitted PRACH) from which the terminal received the initial connection signal (e.g., SSB, CSI-RS). For example, the terminal's UL transmission beam and DL reception beam may have the same or similar directionality. The base station can successfully receive PRACH from the terminal by using the same beams or beams with similar directionality for the transmission and reception of the mutually coupled DL resources and UL resources, and can determine the DL resources (e.g., SSB resources or SSB) and DL initial beams selected by the terminal based on the mutual coupling relationship. That is, the terminal can report the initial beam to the base station in an implicit manner through the method described above. The UL beam corresponding to the DL initial beam may be referred to as the UL initial beam.

[0095] In the present disclosure, a PRACH resource may mean a PRACH occasion (or, a PRACH occasion resource). One or more random access preambles (or sequences) may be mapped to the PRACH resource or PRACH occasion, and the PRACH resource or PRACH occasion may further include a cyclic prefix (CP) for asynchronous transmission, a guard period, etc. The PRACH resource or PRACH occasion may be placed in one or more slot(s) and may include one or more symbol(s). Additionally, the PRACH resource or PRACH occasion may include one or more RB(s) or subcarrier(s).

[0096] Meanwhile, during the initial connection process, the terminal may determine multiple beams as optimal beam(s) or suitable beam(s). Additionally, the terminal may select the multiple beams as optimal beam(s) or suitable beam(s). In the present disclosure, the terminal selecting multiple beams may mean selecting resources (e.g., DL resources) corresponding to the multiple beams. In one embodiment, the multiple beams may be SSB beams and the multiple resources may be SSB resources. That is, the terminal may receive multiple SSBs that are repeatedly transmitted based on multiple beams, and may select two or more SSBs among the multiple SSBs as suitable beams. The multiple SSBs may include a first SSB and a second SSB. Without loss of generality, the first SSB beam and the second SSB beam may be the best beam and the second best beam, respectively. The beam(s) selected by the terminal may be used at least during the initial connection process and may be referred to as initial beam(s). That is, the terminal can select multiple initial beams. Additionally, in this disclosure, the term "beam" will be used as a concept including a receiving beam, a transmitting beam, a transmitting / receiving beam pair, a spatial QCL, a TCI, a TCI state, etc.

[0097] The optimal beam or suitable beam can be determined based on a beam quality measurement operation. For example, the terminal can measure the beam quality of M SSBs (e.g., RSRP, SINR, L1-RSRP, L1-SINR) and select L SSBs with the highest beam quality based on a relative criterion or select L SSBs that satisfy an absolute criterion value (L is a natural number less than or equal to M). Here, the SSBs may be SSBs that are actually transmitted or SSBs that are designated to be actually transmitted to the terminal based on a signaling procedure (e.g., transmission of system information, RRC signaling procedure).

[0098] During the process of performing the initial connection procedure, the terminal may report the selected plurality of beams to the base station. The base station may perform DL and UL communication with the terminal based on the reported plurality of beams. Additionally, the base station may perform transmission based on a multiple TRP transmission method with the terminal based on the reported plurality of beams. In this disclosure, specific methods for the terminal to report a plurality of initial beams to the base station will be proposed. In the embodiments, the plurality of initial beams will be described as limited to two SSBs for convenience of explanation, but the embodiments of this disclosure are not limited thereto and may be extended to operations based on measurement signals other than SSBs (e.g., CSI-RS, DM-RS) or to report three or more beams.

[0099]

[0100] Implicit method

[0101] Multiple initial beams may be reported to a base station by an implicit method. For example, multiple SSB beams may be reported to a base station by an operation of transmitting multiple PRACHs. A terminal may report a first SSB beam to a base station by transmitting a first preamble from a first PRACH resource associated with a first SSB, and may report a second SSB beam to a base station by transmitting a second preamble from a second PRACH resource associated with a second SSB. The above-described method may be referred to as (Method 100).

[0102] According to one embodiment, the first preamble and the second preamble may be transmitted within the same random access procedure. Here, the random access procedure may be a contention-based or contention-free method. For example, the terminal may perform a contention-based random access procedure and transmit the first preamble and the second preamble in the Msg1 transmission step.

[0103] FIG. 4 is a conceptual diagram illustrating a first embodiment of a method for reporting a plurality of initial beams based on (method 100).

[0104] Referring to FIG. 4, the first preamble and the second preamble can be transmitted within the same PRACH transmission period. That is, the first PRACH resource for transmitting the first preamble and the second PRACH resource for transmitting the second preamble can belong to the same period. The same transmission power can be applied to the transmission of the first preamble and the second preamble. If the number of ROs within one PRACH period is insufficient so that not all valid SSBs (e.g., SSBs actually transmitted) are mapped to ROs, the SSBs can be mapped to ROs belonging to multiple PRACH periods, and the multiple PRACH periods may be referred to as an SSB-RO association period, an SSB-RO association pattern period, etc. In this case, the first preamble and the second preamble can be transmitted, respectively, through the first PRACH resource and the second PRACH resource belonging to the same SSB-RO association cycle or the same SSB-RO association pattern cycle.

[0105] After transmitting the first preamble and the second preamble, the terminal may receive Msg2 or RAR in response. The start time of the RAR window (e.g., start slot, start subframe) may be determined based on either the first PRACH resource or the second PRACH resource. The said PRACH resource may be a later or earlier PRACH resource in terms of time. Specifically, the said PRACH resource may mean a PRACH resource with a later (or earlier) end symbol, a PRACH resource with a later (or earlier) start symbol, etc. Alternatively, the said PRACH resource may be a PRACH resource corresponding to an SSB with a higher (or lower) beam quality, i.e., the first PRACH resource (or the second PRACH resource). In this case, information regarding beam quality may be additionally reported to the base station, and the base station may identify the first PRACH resource (or the second PRACH resource) based on said information. For example, information regarding beam quality may be transmitted through the PUSCH resource(s) associated with the first PRACH resource and / or the second PRACH resource. The cyclic redundancy check (CRC) of the PDCCH scheduling the PDSCH containing Msg2 may be scrambled into the random access-radio network temporary identifier (RA-RNTI) and transmitted. In this case, the RA-RNTI value may be determined based on the time resource information (e.g., subframe index, slot index, index of the first symbol, index of the last symbol, etc.) and / or frequency resource information (e.g., the order in which ROs are mapped in the frequency domain or the index of the RO) of either the first PRACH resource or the second PRACH resource.In addition, the base station may include the ID of the preamble received from any one of the above-mentioned PRACH resources in the Msg2 RAR and transmit it to the terminal.

[0106] Meanwhile, it may be difficult for the base station to clearly distinguish whether the received first preamble and second preamble were transmitted by the same terminal or by different terminals. In one embodiment, the base station may consider both possibilities and transmit both a first RAR corresponding to the first preamble and a second RAR corresponding to the second preamble. Each RAR may include the ID of the corresponding preamble, and the time window in which each RAR is transmitted may be determined based on the transmission time of the corresponding PRACH resource. Additionally, the RA-RNTI applied to the PDCCH for receiving each RAR may be determined based on the time resource information and / or frequency resource information of the corresponding PRACH resource.

[0107] A terminal that has transmitted the first preamble and the second preamble can receive the first RAR and the second RAR, and can confirm that each preamble has been successfully transmitted by checking the preamble ID included in each RAR. At this time, the first RAR may include scheduling information regarding a first PUSCH resource for transmitting Msg3, and the second RAR may include scheduling information regarding a second PUSCH resource for transmitting Msg3.

[0108] In one embodiment, the terminal can transmit Msg3 in both the first PUSCH resource and the second PUSCH resource. If the terminal ID (e.g., TMSI) included in the plurality of Msg3 transmissions matches, the base station may consider that the first PUSCH and the second PUSCH were transmitted by the same terminal, and may consider that the first preamble and the second preamble were transmitted by the same terminal, thereby confirming that the terminal has selected a plurality of initial beams.

[0109] In another embodiment, the terminal may transmit Msg3 from either the first PUSCH resource or the second PUSCH resource. In this case, Msg3 may additionally include information regarding the preamble transmitted by the terminal. For example, if the terminal transmits Msg3 from the first PUSCH resource, the Msg3 may at least include information regarding the ID of the second preamble corresponding to the second PUSCH resource. Or, if the terminal transmits Msg3 from the second PUSCH resource, the Msg3 may at least include information regarding the ID of the first preamble corresponding to the first PUSCH resource. In other words, explicit information may also be additionally reported to the base station in (Method 100). When a base station transmits Msg3 from a first PUSCH resource, it may determine that the terminal transmitting Msg3 has transmitted a first preamble associated with the first PUSCH resource, and additionally, based on the information contained in Msg3, it may determine that the same terminal has also transmitted a second preamble. Alternatively, Msg3 may include both information regarding the ID of the first preamble and information regarding the ID of the second preamble. The base station may transmit Msg4 to the terminal in response to the Msg3 PUSCH. Msg4 may primarily include a terminal ID (e.g., TMSI) and additionally include information regarding the first preamble and the second preamble.

[0110] FIG. 5 is a conceptual diagram illustrating a second embodiment of a method for reporting a plurality of initial beams based on (method 100).

[0111] Referring to FIG. 5, the first preamble and the second preamble can be transmitted in different PRACH transmission periods. That is, the first PRACH resource and the second PRACH resource can belong to different periods. Similarly, in this embodiment, depending on the mapping configuration between the SSB and the RO, the PRACH period can be extended to an SSB-RO association period, an SSB-RO association pattern period, etc. At this time, the transmission order of the first preamble and the second preamble can be determined based on the beam quality of the corresponding SSB resources. For example, the first preamble corresponding to the first SSB, which is the optimal beam, can be transmitted first, and the second preamble corresponding to the second SSB can be transmitted in a subsequent period.

[0112] Specifically, the terminal may receive Msg2 or the first RAR in response thereto after transmitting the first preamble. The start time of the RAR window (e.g., start slot, start subframe) may be determined based on the first PRACH resource. The terminal may transmit the second preamble in a second PRACH resource belonging to any PRACH period that appears after receiving the first RAR. At this time, since the first preamble has been successfully transmitted and the second preamble is not a retransmission of the first preamble, it is unnecessary to apply power ramping to the transmission of the second preamble. That is, the same transmission power may be applied to the first preamble and the second preamble. Alternatively, information indicating whether to apply power ramping to the second preamble may be included in system information or in the Msg2 or the first RAR and transmitted to the terminal, and the terminal may transmit the second preamble with or without applying power ramping based on said information. Both the first preamble transmission and the second preamble transmission can be considered as Msg1. In this case, the terminal may transmit Msg1 corresponding to the first preamble, receive Msg2, and then transmit Msg1 corresponding to the second preamble again. The terminal may then receive Msg2 or the second RAR, which is a response to the reception of the second preamble. That is, the terminal may receive Msg2 or RAR twice (or multiple times) within one random access procedure.

[0113] The terminal may transmit Msg3 PUSCH after the transmission of the second preamble or after the reception of the second RAR. In this case, the resource allocation information of Msg3 PUSCH may be included in the second RAR, which is the reception response of the second preamble, but may not be included in the first RAR, which is the reception response of the first preamble. In this case, the terminal may ignore or not use the resource allocation information of Msg3 PUSCH included in the first RAR. As described above, Msg3 may include information regarding the ID of the first preamble, or may include both information regarding the ID of the first preamble and information regarding the ID of the second preamble. Based on the above information, the base station may confirm that the terminal has transmitted multiple preambles.

[0114] Alternatively, the terminal may transmit a Msg3 PUSCH corresponding to the first preamble before transmitting the second preamble, or transmit the earlier resource first and the later resource next according to the chronological order of the second PRACH resource and the Msg3 PUSCH resource. That is, the terminal may transmit the second preamble first and then transmit the Msg3 PUSCH corresponding to the first preamble, or transmit the Msg3 PUSCH corresponding to the first preamble first and then transmit the second preamble. Resource allocation information for the Msg3 PUSCH corresponding to the first preamble may be included in the first RAR, which is the reception response of the first preamble. In this case, Msg3 PUSCH may be transmitted twice, and as described above, if the terminal ID included in the multiple Msg3 transmissions matches, the base station may consider that the multiple Msg3 PUSCHs were transmitted by the same terminal, and may confirm that the terminal selected multiple initial beams by considering that the first preamble and the second preamble were transmitted by the same terminal.

[0115] According to the first embodiment described with reference to FIG. 4, the terminal may transmit corresponding preambles without distinguishing priorities among the SSB beams. The base station may also not assign priorities among the SSB beams corresponding to the received preambles. The base station may select any beam among the first SSB beam and the second SSB beam and transmit a RAR based on the selected beam. Since the terminal does not know which beam the RAR will be transmitted based on, it may monitor the Msg2 PDCCH (i.e., the PDCCH that schedules the PDSCH containing the RAR) based on both the first SSB beam and the second SSB beam. To this end, a plurality of search space sets may be configured for monitoring the Msg2 PDCCH. In the plurality of search space sets, the PDCCH may be monitored based on different beams (or different receiving beams, different QCL assumptions, different TCIs). This operation may increase the reception complexity of the terminal.

[0116] According to the second embodiment described with reference to FIG. 5, priority can be applied among a plurality of SSB beams. For example, an SSB beam (i.e., the first SSB beam) corresponding to a preamble transmitted first (i.e., the first preamble) may have a higher priority than an SSB beam (i.e., the second SSB) corresponding to a preamble transmitted later (i.e., the second preamble). For example, the first SSB beam and the second SSB beam may be referred to as the primary beam and the secondary beam, respectively. The RAR (i.e., Msg2 PDCCH and Msg2 PDSCH) corresponding to the first preamble may be received based on the first SSB beam. On the other hand, the beam that can be used in the receiving stage of the RAR (i.e., Msg2 PDCCH and Msg2 PDSCH) corresponding to the second preamble may include both the first SSB beam and the second SSB beam. However, to maximize the reception performance of the RAR corresponding to the second preamble, the RAR corresponding to the second preamble may be monitored and received based on the first SSB beam. Alternatively, the RAR corresponding to the second preamble may be monitored and received based on the corresponding second SSB beam.

[0117] Msg3 PUSCH can be transmitted based on a transmission beam (or, transmission space filter, UL TCI, etc.) identical to the first preamble corresponding to the primary beam. Additionally, Msg4 (i.e., PDCCH and PDSCH) can be monitored and received based on the first SSB beam.

[0118] According to another embodiment, the terminal may sequentially perform a plurality of random access procedures, and the first preamble and the second preamble may be transmitted in different random access procedures. For example, the terminal may perform a first random access procedure and transmit the first preamble during the Msg1 transmission step of the first random access procedure. After the first random access procedure is completed, the terminal may perform a second random access procedure and transmit the second preamble during the Msg1 transmission step of the second random access procedure.

[0119] FIG. 6 is a conceptual diagram illustrating a third embodiment of a method for reporting a plurality of initial beams based on (method 100).

[0120] Referring to FIG. 6, the terminal may transmit a first preamble and a second preamble, respectively, based on a first random access procedure and a second random access procedure. The first random access procedure may be performed in a contention-based manner, and the second random access procedure may be performed in a non-contention-based manner. That is, the second preamble or the second PRACH resource to which the second preamble is transmitted may be specified by the base station and transmitted to the terminal. Information regarding the second preamble and / or the second PRACH resource may be signaled to the terminal within the first random access procedure. For example, said information may be included in an RRC message transmitted via Msg4 of the first random access procedure.

[0121] The PRACH transmission power of the first random access procedure and the PRACH transmission power of the second random access procedure can be set independently of each other, and the first preamble and the second preamble can be transmitted based on each PRACH transmission power. Alternatively, the same transmission power (e.g., initial transmission power) can be applied to the first preamble and the second preamble. However, power ramping operations following the retransmission of the preamble can be performed independently for the first preamble and the second preamble, respectively.

[0122] The above third embodiment may be suitable for a multi-cell scenario or a multi-TA (timing advance) scenario. When the first SSB and the second SSB are transmitted from different cells, or when the distance between the terminal and the TRP transmitting the first SSB differs significantly from the distance between the terminal and the TRP transmitting the second SSB, the base station may measure the UL timing for each cell or each TRP by receiving the first preamble and the second preamble, and may set TA values ​​to be applied to each cell or each TR to the terminal. However, in a single-cell scenario and / or a single TA scenario, transmitting multiple preambles to report multiple initial beams may unnecessarily occupy a large amount of UL resources or increase the delay time required for beam reporting. Additionally, according to the above embodiments, the number of reported beams may be limited to a maximum of two.

[0123]

[0124] Explicit method

[0125] Among a plurality of initial beams, some beam(s) may be reported by an implicit method, and the remaining beam(s) may be reported based on explicit configuration information or control information. For example, among a plurality of SSB beams, some SSB beam(s) (e.g., optimal SSB beams) may be reported to the base station by an operation of transmitting associated PRACH(s), and information regarding the remaining SSB beam(s) may be reported by including it in a UL signal. Assuming two SSB initial beams, the terminal may report the first SSB beam to the base station by transmitting a first preamble from a first PRACH resource associated with the first SSB, and for the second SSB, may report to the base station by including information regarding the second SSB and the second SSB resource in a UL signal. For example, the above information may include the SSB index of the second SSB, the ID of the cell to which the second SSB belongs (e.g., physical layer cell ID), the beam quality measurement of the second SSB (e.g., L1-RSRP, L1-SINR, etc.). For convenience, the above information may be referred to as beam information or beam report information for the second SSB. The above-described method may be referred to as (Method 200).

[0126] FIG. 7 is a conceptual diagram illustrating a first embodiment of a method for reporting a plurality of initial beams based on (method 200).

[0127] Referring to FIG. 7, a plurality of initial beams may be reported based on a four-step random access (RA) procedure. In the first step (S710) of the RA procedure, the terminal may report the first SSB beam to the base station by transmitting a first preamble from a first PRACH resource associated with the first SSB, and in the second step (S720) of the RA procedure, receive a response message to the first preamble, such as Msg2 or RAR. In the third step (S730) of the RA procedure, the terminal may transmit Msg3 (e.g., PUSCH) based on UL grant information included in the RAR. At this time, Msg3 may include information indicating the existence of additional beam(s) (e.g., a second SSB beam) to be reported. The existence of additional beams may be determined by the terminal, and the information may be determined by the terminal. After transmitting Msg3, the terminal may receive Msg4 (e.g., PDCCH and PDSCH) in the fourth step (S740) of the RA procedure. Msg4 may include an RRC connection setup message. The RRC connection setup message may include configuration information (e.g., servingCellConfigCommon, servingCellConfigDedicated) for the terminal to configure a serving cell.

[0128] If, in the third step (S730), the terminal transmits to the base station a message indicating the existence of additional beam(s) (e.g., a second SSB beam) or a message requesting resources to report additional beam(s) (e.g., a second SSB beam), in the fourth step (S740) of the RA procedure, the base station may transmit to the terminal, in a PDSCH (e.g., Msg4), information (first instruction information) indicating UL resources for transmitting beam information of said additional beam(s) (e.g., a second SSB beam) and / or information (second instruction information) indicating to perform a beam reporting operation. The first instruction information and / or the second instruction information may be included in an RRC message or an RRC connection setup message. Alternatively, the first instruction information and / or the second instruction information may be defined in the form of a message generated at the MAC layer (e.g., MAC CE). That is, the first instruction information and / or the second instruction information may be included in a PDSCH (e.g., Msg4) and transmitted to the terminal. In this case, the PDSCH may simultaneously include control messages of the RRC layer and control messages of the MAC layer. Alternatively, the first instruction information and / or the second instruction information may be received via a DCI. For example, the DCI may be a DCI for scheduling the Msg4 PDSCH. For convenience, the UL resource may be referred to as a beam reporting UL resource. In the final step (S750), the terminal may transmit to the base station the beam information of the additional beam(s) (e.g., the second SSB beam) carried in the beam reporting UL resource.

[0129] FIG. 8 is a conceptual diagram illustrating a second embodiment of a method for reporting a plurality of initial beams based on (method 200).

[0130] Referring to FIG. 8, a plurality of initial beams may be reported based on a two-stage random access procedure. In the first stage (S810) of the RA procedure, the terminal may report the first SSB beam to the base station by transmitting a first preamble from a first PRACH resource associated with the first SSB. Additionally, in the first stage (S810), the terminal may transmit to the base station information indicating the existence of additional beam(s) (e.g., a second SSB beam) to be reported by the terminal, carried in a UL resource (e.g., PUSCH). The first PRACH resource may be referred to as MsgA PRACH, and the UL resource (e.g., PUSCH) may be referred to as MsgA PUSCH. In the second stage (S820) of the RA procedure, the terminal may receive a response message to the first preamble, such as MsgB or RAR. MsgB may include an RRC connection setup message.

[0131] If, in the first step (S810), the terminal transmits to the base station a message indicating the existence of additional beam(s) (e.g., a second SSB beam) or a message requesting a resource to report additional beam(s) (e.g., a second SSB beam), the base station may, in the second step (S820), transmit to the terminal MsgB information instructing the terminal to a UL resource for transmitting beam information of the additional beam(s) (e.g., a second SSB beam) and / or information instructing the terminal to perform a beam reporting operation. In the step (S830), the terminal may transmit to the base station the beam information of the additional beam(s) (e.g., a second SSB beam) carried on the beam reporting UL resource.

[0132]

[0133] According to another embodiment, information regarding additional beam(s) may be transmitted to a base station in the third step (S730) of a four-step random access procedure or in the first step (S810) of a two-step random access procedure. For example, information regarding additional beam(s) may be transmitted by mapping it to an explicit payload in Msg3 PUSCH or MsgA PUSCH. In this case, a field or flag indicating the presence of additional beam(s) to be reported may be transmitted via Msg3 PUSCH or MsgA PUSCH along with the information regarding additional beam(s). If there are no additional beams to be reported, the terminal may transmit to the base station a bit sequence or field to which information regarding additional beam(s) is mapped, by setting it to a specific bit value (e.g., all-zero, all-one). According to the above embodiment, additional beams or second beams may be reported to the base station at an earlier time.

[0134]

[0135] The additional beam(s) mentioned above may be reported conditionally. For example, the terminal may report the additional beam(s) if the difference between the beam quality of the additional beam(s) and the beam quality of the optimal beam is within a reference value. Alternatively, the beam quality of the additional beam(s) may be compared with a beam quality reference value, and the terminal may report the additional beam(s) if the beam quality of the additional beam(s) is superior to the beam quality reference value. Configuration information regarding the reference value, etc., may be included in system information (e.g., SIB1) or broadcast information and signaled to the terminal. Alternatively, the reference value may be determined by implementation by the terminal instead of being defined in technical specifications or set by the base station.

[0136]

[0137] The beam report UL resource may be a UL control channel (e.g., PUCCH). Given that the amount of beam report information is typically small, it may be desirable for the beam report information to be transmitted via PUCCH. The PUCCH resource may be a periodic PUCCH resource or a semi-permanent PUCCH resource. In this case, the beam report information may be reported repeatedly and periodically even after the terminal establishes an RRC connection. Alternatively, the PUCCH resource may be a non-periodic PUCCH resource. The beam report information may be transmitted once from the non-periodic PUCCH resource, and if the base station needs to receive additional beam reports from the terminal, it may allocate a separate UL resource for this purpose. Configuration information for the non-periodic PUCCH resource may be included in system information (e.g., SIB1) or broadcast information and transmitted to the terminal. At the same time, configuration information for non-periodic PUCCH resources may be included in terminal-specific RRC messages (e.g., RRC connection setup messages, serving cell configuration information, etc.) and transmitted to the terminal via Msg4. For example, information such as the slot, symbol, and subframe to which the beam reporting UL resource is mapped may be included in Msg4 or determined based on the time at which Msg4 is received (e.g., slot, symbol, subframe). In this case, the terminal can determine the location of the beam reporting UL resource based on the reception of Msg4. Beam reporting information may be considered as UCI (uplink control information) and may be generated and processed at the physical layer of the terminal.

[0138] Alternatively, the beam reporting UL resource may be a UL data channel (e.g., PUSCH). If multiple additional beams are reported or the beam quality values ​​of the additional beams are reported together, the amount of beam reporting information may increase and the amount of beam reporting information may vary. In this case, it may be desirable to transmit the beam reporting information via PUSCH. The PUSCH may be a non-periodic PUSCH resource allocated for one-time transmission. Alternatively, the PUSCH may be a periodic PUSCH resource or a semi-permanent PUSCH resource allocated repeatedly or semi-permanently. According to an embodiment, the scheduling and resource allocation information of the PUSCH may be transmitted to the terminal via system information (e.g., SIB1) and / or Msg4. In particular, a UL grant message containing the resource allocation information of the PUSCH may be included in Msg4. Here, saying that a message is included in Msg4 means that the message is included as a sub-parameter of the message constituting Msg4, as well as being included and transmitted together with the physical resource to which Msg4 is transmitted (e.g., DL resource, PDSCH, PDCCH).

[0139] According to another embodiment, scheduling and resource allocation information for PUSCH to transmit beam reporting may be transmitted to the terminal via a separate DL signal (e.g., DCI, scheduling DCI). For example, the terminal may transmit a scheduling request (SR) to the base station to request the allocation of beam reporting UL resources, and the base station may dynamically allocate beam reporting UL resources via DCI in response. The UL resources allocated by the terminal's request do not necessarily have to be PUSCH, and can be PUCCH. An RRC connection setup completion message corresponding to the response message of Msg4 may be included and transmitted together with the UL data channel (e.g., PUSCH) through which beam reporting information is transmitted.

[0140]

[0141] Beam reporting resources may be repeatedly deployed, and the terminal may repeatedly transmit beam reporting information from the repeated beam reporting resources. The terminal may repeatedly transmit PUCCH, and beam reporting information may be included in each of the repeatedly transmitted PUCCHs (or all PUCCH instances). Alternatively, the terminal may repeatedly transmit PUSCH, and beam reporting information may be included in each of the repeatedly transmitted PUSCHs (or all PUSCH instances). The number of repeated transmissions of a beam reporting UL resource may be semi-statically set via system information (e.g., SIB1) or terminal-specific RRC messages, or dynamically indicated based on MAC layer or physical layer signaling (e.g., configuration information included in Msg4, UL grant included in Msg4, DCI).

[0142]

[0143] Even when beam report information is transmitted through a UL data channel (e.g., PUSCH), the beam report information may be defined as a UCI. In this case, the beam report information may be multiplexed with a PUSCH TB (transport block) or UL-SCH (uplink-shared channel) and mapped together to PUSCH resources according to a predetermined rule. A PUSCH payload, such as a TB or UL-SCH, may be mapped by rate-matching the remaining REs (resource elements), excluding the REs (resource elements) to which the beam report information is mapped. Alternatively, the beam report information may be mapped by applying puncturing to the REs (resource elements) to which the PUSCH payload, such as a TB or UL-SCH, is mapped. Alternatively, beam report information may be defined as a MAC layer message (e.g., MAC CE) or an upper layer message (e.g., RRC message), and the terminal may map the beam report information to a PUSCH resource as part of a TB (transport block) or UL-SCH (uplink-shared channel).

[0144]

[0145] Beam reporting information may include information regarding L additional initial beam(s). That is, the beam reporting information may include information regarding resource index(s) (e.g., SSB index(s)), cell index(s) (e.g., physical layer cell ID(s)), beam quality (e.g., L1-RSRP, L1-SINR, etc.) for up to L beam(s). The value of L may be determined arbitrarily by the terminal, and accordingly, the beam reporting payload size may be variable. Alternatively, the value of L may be fixed as a value set by the base station, and accordingly, the beam reporting payload size may be fixed. As described in the embodiments above, the additional beam may be an SSB beam. Alternatively, the additional beam may additionally include a CSI-RS beam. During the initial connection process, the terminal may receive CSI-RS in addition to the SSB from the base station, measure the beam quality of the received CSI-RS, and determine whether it is suitable as an initial beam. Additionally, the additional beam may include a UL beam. If the terminal determines that the UL beam used or verified during the process of performing a random access procedure is suitable as an initial beam, it may report the UL beam to the base station by the method described above. Additionally, the beam reporting information may further include information regarding the type or category of the reported beam quality metric, the event that triggered the beam reporting, etc.

[0146]

[0147] As described above, the terminal can select multiple SSBs transmitted from multiple cells as the initial beam. For example, the terminal can select a first SSB and a second SSB, and the first SSB and the second SSB may be transmitted from a first cell and a second cell, respectively. During the reception of the first SSB, the terminal can obtain the cell ID of the first cell, and during the reception of the second SSB, the terminal can obtain the cell ID of the second cell. Through this, the terminal can determine which cell the selected SSB beams belong to, and, following the method described above, can report to the base station by including information regarding the cell to which the initial beam belongs (e.g., cell ID) in the beam report information. For example, the beam report information may include beam-related information composed of a combination of a cell ID and an SSB index.

[0148] Based on the above information, the base station can determine whether multiple initial beams selected by the terminal belong to the same cell or to different cells. In the latter case, the base station may instruct the terminal to perform a random access procedure. The random access procedure may be a procedure performed independently of the additional beam reporting procedure described above. The random access procedure may be a contention-based method, and the terminal may be instructed by the base station to receive a PRACH resource to transmit a preamble.

[0149] Alternatively, before reporting beam reporting information (e.g., additional beam information) to the base station, the terminal may first inform the base station of information regarding whether the initial beams it has selected belong to the same cell, or whether additional random access procedures (e.g., random access procedures for other cells, contention-based random access procedures) need to be performed. For example, the terminal may inform the base station of said information during the Msg3 or PUSCH transmission phase before transmitting the beam reporting UL resource. Based on said information, the base station may instruct the terminal to perform additional random access procedures via Msg4. Additional beams may be reported to the base station implicitly or explicitly within the additional random access procedure, in which case the beam reporting UL resource may be unnecessary. That is, the terminal may selectively be allocated either the beam reporting UL resource (e.g., PUCCH, PUSCH) or the PRACH resource depending on whether the selected initial beams (e.g., SSB beams) belong to a single cell. According to the method described above, the additional random access procedure may be triggered at an earlier time.

[0150]

[0151] The above embodiments may be applied to cases where the beam width or coverage of the first SSB beam and the second SSB beam is equal and cases where they are different. Additionally, the above embodiments may be applied when the first SSB and the second SSB belong to the same SSB group or when no SSB group is configured on the terminal, and may also be applied when the first SSB and the second SSB belong to different SSB groups. In this case, the beam reporting information may additionally include information regarding the SSB group to which the SSB beam belongs (e.g., an SSB group index).

[0152]

[0153] In the above embodiments, the first SSB may be the SSB of the cell where the terminal is camping. Alternatively, the first SSB may be the SSB of a cell other than the cell where the terminal is camping (e.g., a neighbor cell). That is, even if the terminal determines that the neighbor cell's SSB is the optimal beam, instead of performing a cell reselection procedure to the neighbor cell, the terminal may report the neighbor cell's SSB as the optimal initial beam to the base station. Based on the reported beam information, the base station may instruct the terminal to perform a handover procedure to the neighbor cell. The handover procedure may be performed after the terminal has established an RRC connection with the cell where it is camping.

[0154]

[0155] In the above embodiments, beam information or beam reporting information may refer to CSI or CSI information. That is, the terminal can calculate the CSI based on received SSB resources, CSI-RS resources, etc., and can report the derived CSI to the base station by the method described above. For example, the CSI may be transmitted to the base station through the beam reporting UL resource. The CSI may include not only beam quality values ​​but also CQI (channel quality indicator), PMI (precoding matrix indicator), RI (rank indicator), CRI (CSI-RS resource indicator), SSBRI (SSB resource indicator), LI (layer indicator), etc. Additionally, the beam information may be a specific type of CSI. That is, the beam information may be included in the CSI and reported to the base station through a CSI reporting operation. The beam reporting UL resource may be interpreted as a UL resource for CSI reporting.

[0156]

[0157] The operation of the method according to an embodiment of the present invention can be implemented as a computer-readable program or code on a computer-readable recording medium. A computer-readable recording medium includes all types of recording devices in which information that can be read by a computer system is stored. Additionally, the computer-readable recording medium may be distributed across networked computer systems, allowing computer-readable programs or code to be stored and executed in a distributed manner.

[0158] In addition, computer-readable recording media may include hardware devices specifically configured to store and execute program instructions, such as ROM, RAM, and flash memory. Program instructions may include machine code, such as that generated by a compiler, as well as high-level language code that can be executed by a computer using an interpreter, etc.

[0159] Some aspects of the invention have been described in the context of a device, but may also be described according to a corresponding method, wherein a block or device corresponds to a method step or a feature of a method step. Similarly, aspects described in the context of a method may also be described according to a corresponding block or item or a feature of a corresponding device. Some or all of the method steps may be performed by (or using) a hardware device, such as, for example, a microprocessor, a programmable computer, or an electronic circuit. In some embodiments, at least one of the most important method steps may be performed by such a device.

[0160] In the embodiments, a programmable logic device (e.g., a field-programmable gate array) may be used to perform some or all of the functions of the methods described herein. In the embodiments, the field-programmable gate array may operate with a microprocessor to perform one of the methods described herein. Generally, it is preferable that the methods be performed by some hardware device.

[0161] Although the present invention has been described with reference to preferred embodiments, those skilled in the art will understand that various modifications and changes can be made to the invention without departing from the spirit and scope of the invention as described in the following claims.

Claims

1. By means of a terminal, A step of performing an SSB reception operation to receive SSBs (synchronization signal blocks) from a base station; A step of determining a first SSB resource and a second SSB resource based on the above SSB reception operation; A step of transmitting a first preamble from a first PRACH (physical random access channel) resource corresponding to the first SSB resource to the base station; and A step comprising transmitting information regarding the second SSB resource to the base station via the first uplink (UL) resource, method.

2. In Claim 1, A method further comprising the step of receiving from the base station a first instruction information indicating the first UL resource and / or a second instruction information indicating to transmit information about the second SSB resource through the first UL resource. method.

3. In Claim 2, The first instruction information and / or the second instruction information is received from the base station via downlink control information (DCI), method.

4. In Claim 2, The first instruction information and / or the second instruction information are generated at the MAC (medium access control) layer or RRC (radio resource control) layer of the base station and received from the base station via the PDSCH (physical downlink shared channel), method.

5. In Claim 1, The above-mentioned first UL resource is a PUCCH (physical uplink control channel) resource, method.

6. In Claim 1, The above-mentioned first UL resource is a PUSCH (physical uplink shared channel) resource indicated by a RAR (random access response) grant received from the base station within a random access (RA) procedure for the base station, or a PUSCH resource transmitted after receiving a Msg4 (message 4) PDSCH according to the RA procedure, method.

7. In Claim 1, Prior to the step of transmitting information regarding the second SSB resource to the base station, the method further includes the step of transmitting information indicating the existence of information regarding the second SSB resource to the base station. method.

8. In Claim 7, Information indicating the existence of information regarding the above-mentioned second SSB resource is transmitted to the base station via Msg3(message 3) PUSCH within the RA procedure for the base station, method.

9. In Claim 1, The step of transmitting information about the second SSB resource to the base station is performed when the reception quality of the SSB received through the second SSB resource satisfies a reference value. method.

10. By the method of the base station, A step of transmitting SSBs (synchronization signal blocks); A step of receiving a first preamble from a first PRACH (physical random access channel) resource corresponding to a first SSB resource determined based on the above SSBs from a terminal; and The step of receiving information about a second SSB resource determined based on the SSBs from the terminal via a first uplink (UL) resource, method.

11. In Claim 10, The method further comprises the step of transmitting to the terminal a first instruction information indicating the first UL resource and / or a second instruction information indicating to transmit information about the second SSB resource through the first UL resource. method.

12. In Claim 11, The above first instruction information and / or the above second instruction information is transmitted to the terminal via downlink control information (DCI), method.

13. In Claim 11, The above first instruction information and / or the above second instruction information is generated at the MAC (medium access control) layer or RRC (radio resource control) layer of the base station and transmitted to the terminal via the PDSCH (physical downlink shared channel), method.

14. In Claim 10, The above-mentioned first UL resource is a PUCCH (physical uplink control channel) resource, method.

15. In Claim 10, The first UL resource is a PUSCH (physical uplink shared channel) resource indicated by a RAR (random access response) grant transmitted to the terminal within a random access (RA) procedure performed with the terminal, or a PUSCH resource received after the transmission of Msg4 (message 4) PDSCH according to the RA procedure, method.

16. In Claim 10, Prior to the step of receiving information about the second SSB resource from the terminal, the method further includes the step of receiving information indicating the existence of information about the second SSB resource from the terminal. method.

17. In Claim 16, Information indicating the existence of information regarding the above-mentioned second SSB resource is received from the terminal via Msg3(message 3) PUSCH within the RA procedure performed with the terminal, method.

18. In Claim 10, Information regarding the second SSB resource is received when the reception quality of the SSB received through the second SSB resource at the terminal satisfies a reference value, method.

19. A terminal comprising at least one processor, The above at least one processor is the terminal: A step of performing an SSB reception operation to receive SSBs (synchronization signal blocks) from a base station; A step of determining a first SSB resource and a second SSB resource based on the above SSB reception operation; A step of transmitting a first preamble from a first PRACH (physical random access channel) resource corresponding to the first SSB resource to the base station; and Performing the step of transmitting information regarding the second SSB resource to the base station through the first uplink (UL) resource, Terminal.

20. In Claim 19, The above-mentioned first UL resource is a PUSCH (physical uplink shared channel) resource indicated by a RAR (random access response) grant received from the base station within a random access (RA) procedure for the base station, or a PUSCH resource transmitted after receiving a Msg4 (message 4) PDSCH according to the RA procedure, Terminal.

Images