Method and apparatus for transmitting synchronization signal block for network energy saving

Abstract

A method and a device for transmitting a synchronization signal block (SSB) for network energy saving are disclosed. The method of a terminal comprises the steps of: receiving, from a base station, a first message including configuration information of a plurality of period values for an SSB; receiving, from the base station, a second message including information indicating one period value from among the plurality of period values; and performing a reception operation for the SSB on the basis of the period value.

Description

Method and device for transmitting a synchronization signal block for saving network energy

[0001] The present disclosure relates to network energy saving (NES) technology, and more particularly, to a transmission technology of a synchronization signal block (SSB) for NES.

[0002] The development of next-generation communication systems (e.g., new radio (NR) communication systems, sixth generation (6G) communication systems, etc.) is becoming increasingly important as the infrastructure for the proliferation of diverse future convergence services. Next-generation communication systems can support not only conventional mobile communication frequency bands but also millimeter wave, terahertz, and upper-mid bands. These systems can support a wider range of performance indicators and scenarios than conventional communication systems (e.g., long-term evolution (LTE) communication systems). As the processing power of communication nodes (e.g., base stations, terminals) increases, network power consumption (e.g., energy consumption) may increase. To achieve carbon neutrality and secure profitability for telecommunications operators, technologies that reduce power consumption (e.g., energy consumption) of both terminals and base stations may be required.

[0003] The purpose of the present disclosure to solve the above problems is to provide a method and device for transmitting SSB (synchronization signal block) for NES (network energy saving).

[0004] According to embodiments of the present disclosure, a method of a terminal for achieving the above object includes the steps of: receiving a first message from a base station including setting information of a plurality of period values ​​for an SSB (synchronization signal block); receiving a second message from the base station including information indicating one period value among the plurality of period values; and performing a receiving operation for the SSB based on the one period value.

[0005] The above plurality of periodic values ​​may include legacy periodic values ​​set by legacy parameters and one or more additional periodic values ​​set by new parameters.

[0006] A time offset for each of the one or more additional periodic values ​​may be set in the terminal, and based on the one periodic value indicated by the second message being one of the one or more additional periodic values, the receiving operation for the SSB may be performed in a time resource determined based on the one periodic value and the time offset corresponding to the one periodic value.

[0007] The SSB resource sets formed based on the above plurality of periodic values ​​may have an inclusive relationship, and the SSB resources formed based on a longer periodic value among the plurality of periodic values ​​may be a subset of the SSB resources formed based on a shorter periodic value among the plurality of periodic values.

[0008] Based on the second message, the period value of the SSB is dynamically changed, and even in a situation where the period value of the SSB is dynamically changed, the receiving operation for the SSB can be performed in one SMTC (SSB measurement time configuration) window.

[0009] The receiving operation for the SSB may be performed from the earliest SSB cycle after the time of receiving the second message or the time of applying the one cycle value, and the earliest SSB cycle may be the earliest SSB cycle among SSB cycles determined based on the one cycle value.

[0010] The method of the terminal may further include a step of performing a reception operation for the SSB based on a period value indicated before the one period value during an SSB period belonging to a time point of receiving the second message or a time point of applying the one period value.

[0011] The second message may be received on a first carrier, and the receiving operation for the SSB based on the one period value may be performed on a second carrier, and the first carrier may be different from the second carrier.

[0012] Based on the first numerology of the first carrier being different from the second numerology of the second carrier, the point in time at which the one period value is applied can be determined based on the first numerology.

[0013] The first message may be an RRC (radio resource control) message, and the second message may be DCI (downlink control information).

[0014] A method of a base station according to embodiments of the present disclosure for achieving the above object includes the steps of: transmitting a first message including setting information of a plurality of period values ​​for a synchronization signal block (SSB) to a terminal; transmitting a second message including information indicating one period value among the plurality of period values ​​to the terminal; and transmitting the SSB to the terminal based on the one period value.

[0015] The above plurality of periodic values ​​may include legacy periodic values ​​set by legacy parameters and one or more additional periodic values ​​set by new parameters.

[0016] A time offset for each of the one or more additional periodic values ​​may be set in the terminal, and based on the one periodic value indicated by the second message being one of the one or more additional periodic values, the SSB may be transmitted in a time resource determined based on the one periodic value and the time offset corresponding to the one periodic value.

[0017] The SSB resource sets formed based on the above plurality of periodic values ​​may have an inclusive relationship, and the SSB resources formed based on a longer periodic value among the plurality of periodic values ​​may be a subset of the SSB resources formed based on a shorter periodic value among the plurality of periodic values.

[0018] Based on the second message, the period value of the SSB can be dynamically changed, and even in a situation where the period value of the SSB is dynamically changed, the SSB can be transmitted in one SMTC (SSB measurement time configuration) window.

[0019] The above SSB may be transmitted from the earliest SSB cycle after the time point of transmission of the second message or the time point of application of the one cycle value, and the earliest SSB cycle may be the earliest SSB cycle among SSB cycles determined based on the one cycle value.

[0020] The method of the base station may further include a step of transmitting the SSB to the terminal based on a period value indicated before the one period value during an SSB period belonging to a time point of transmission of the second message or a time point of application of the one period value.

[0021] The second message may be transmitted on a first carrier, and the SSB based on the one period value may be transmitted on a second carrier, wherein the first carrier may be different from the second carrier.

[0022] Based on the first numerology of the first carrier being different from the second numerology of the second carrier, the point in time at which the one period value is applied can be determined based on the first numerology.

[0023] The first message may be an RRC (radio resource control) message, and the second message may be DCI (downlink control information).

[0024] According to the present disclosure, a base station can transmit configuration information of a plurality of period values ​​for an SSB (synchronization signal block) to a terminal, and can transmit information indicating one of the plurality of period values ​​to the terminal. The terminal can perform a reception operation for the SSB based on one of the indicated period values ​​among the plurality of period values ​​set by the base station. Based on the above-described method, the SSB period can be dynamically changed. For example, the SSB period can be changed from a long period to a short period, in which case the energy (e.g., power) of a network (e.g., a base station) can be saved, and power consumption in the terminal can also be reduced. The SSB period can be changed from a short period to a long period, in which case the communication performance can be improved.

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

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

[0027] Figure 3a is a conceptual diagram illustrating the first multiplexing pattern of SSB and CORESET.

[0028] Figure 3b is a conceptual diagram illustrating a second multiplexing pattern of SSB and CORESET.

[0029] Figure 3c is a conceptual diagram illustrating the third multiplexing pattern of SSB and CORESET.

[0030] Figure 4 is a conceptual diagram illustrating an embodiment of an SSB dynamic adaptation method.

[0031] FIG. 5 is a conceptual diagram illustrating an embodiment of a method for receiving SSB in a terminal in RRC idle / inactive mode.

[0032] Fig. 6 is a conceptual diagram illustrating an embodiment of a method for receiving SSB in a terminal in RRC connection mode.

[0033] Fig. 7 is a conceptual diagram illustrating an embodiment of a method for receiving SSB in a terminal in RRC connection mode.

[0034] Fig. 8 is a conceptual diagram illustrating an embodiment of a method for receiving SSB in a terminal in RRC connection mode.

[0035] Figure 9 is a conceptual diagram illustrating an embodiment of a method for setting SSB adaptation instruction information.

[0036] Fig. 10 is a conceptual diagram illustrating an embodiment of a method for setting SSB adaptation instruction information.

[0037] Figure 11 is a conceptual diagram illustrating an embodiment of a method for setting SSB adaptation instruction information.

[0038] Figure 12 is a conceptual diagram illustrating an embodiment of a method for setting SSB adaptation instruction information.

[0039] Figure 13 is a conceptual diagram illustrating an embodiment of an SSB transmission method that takes into account the application timing of an SSB adaptation instruction.

[0040] This disclosure may be subject to various modifications and various embodiments. Specific embodiments are illustrated and described in detail in the drawings. However, this is not intended to limit the disclosure to specific embodiments, but rather to encompass all modifications, equivalents, and alternatives falling within the spirit and technical scope of the disclosure.

[0041] While terms such as "first" and "second" may be used to describe various components, these components should not be limited by these terms. These terms are used solely to distinguish one component from another. For example, without departing from the scope of the present disclosure, a first component could be referred to as a "second component," and similarly, a second component could also be referred to as a "first component." The term "and / or" encompasses any combination of multiple related items or any one of multiple related items.

[0042] 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 combinations of one or more of A and B.” Furthermore, 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 combinations of one or more of A and B.”

[0043] When a component is referred to as being "connected" or "connected" to another component, it should be understood that it may be directly connected or connected to that other component, but that there may be other components intervening. Conversely, when a component is referred to as being "directly connected" or "connected" to another component, it should be understood that there are no other components intervening.

[0044] The terminology used in this disclosure is only used to describe specific embodiments and is not intended to limit the present disclosure. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this disclosure, it should be understood that the terms "comprises" or "has" indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not preclude the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0045] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art to which this disclosure pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and shall not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0046] 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 in describing the present disclosure, identical reference numerals will be used for identical components in the drawings, and redundant descriptions of identical components will be omitted.

[0047] 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., a long-term evolution (LTE) communication system, LTE-A communication system), a 5G communication system (e.g., a new radio (NR) communication system), a 6G communication system, etc. The 4G communication system can support communication in a frequency band below 6 GHz, and the 5G communication system can support communication in a frequency band above 6 GHz as well as a frequency band below 6 GHz. The communication system to which embodiments according to the present disclosure are applied is not limited to the contents described below, and the embodiments according to the present disclosure can be applied to various communication systems. Here, the communication system may be used with the same meaning as a communication network, and “LTE” may indicate a “4G communication system,” an “LTE communication system,” or an “LTE-A communication system,” and “NR” may indicate a “5G communication system” or an “NR communication system.”

[0048] In an embodiment, “an operation (e.g., a transmission operation) is set to a communication node” may mean that “setting information for the operation (e.g., an information element, a parameter)” and / or “information instructing performance of the operation” are signaled to the communication node. In other words, “an operation (e.g., a transmission operation) is set to a communication node” may mean that the communication node receives “setting information for the operation (e.g., an information element, a parameter)” and / or “information instructing performance of the operation.” “An information element (e.g., a parameter) is set to a communication node” may mean “the information element is signaled to the communication node (e.g., the communication node receives the information element).” The signaling may be at least one of SI (system information) signaling (e.g., transmission of a system information block (SIB) and / or a master information block (MIB)), RRC signaling (e.g., transmission of RRC parameters and / or upper layer parameters), MAC control element (CE) signaling, or PHY signaling (e.g., transmission of downlink control information (DCI), uplink control information (UCI), and / or sidelink control information (SCI)). A message for SI signaling may be referred to as an SI message, a message for RRC signaling may be referred to as an RRC message, a message for MAC CE signaling may be referred to as a MAC message, and a message for PHY signaling may be referred to as a PHY message. The above-described messages may be expressed as a first message, a second message, a third message, etc.

[0049] In the present disclosure, a phrase including “if (e.g., when ~)” can be expressed as a phrase including “based on (e.g., based on ~)” or a phrase including “in response to (e.g., in response to ~)”. In other words, a phrase including “if ~)” can be interpreted as being identical or similar to a phrase including “based on” or a phrase including “in response to”.

[0050] In this disclosure, "time" may refer to a time point, and "time point" may refer to time. "Time" and "point point" may be used interchangeably. The reception time of a signal or channel may refer to the start time of reception or the end time of reception. The transmission time of a signal or channel may refer to the start time of transmission or the end time of transmission.

[0051] Figure 1 is a conceptual diagram illustrating embodiments of a communication system.

[0052] 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). In addition, the communication system (100) may further include a core network (e.g., a serving-gateway (S-GW), a packet data network (PDN)-gateway (P-GW), a mobility management entity (MME)). If the communication system (100) is a 5G communication system (e.g., a new radio (NR) system), the core network may include an access and mobility management function (AMF), a user plane function (UPF), a session management function (SMF), etc.

[0053] A plurality of communication nodes (110 to 130) can support a communication protocol (e.g., LTE communication protocol, LTE-A communication protocol, NR communication protocol, etc.) specified in the 3GPP (3rd generation partnership project) standard. The plurality of 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 plurality of communication nodes may mean an apparatus or a device. The embodiments may be performed by a device or apparatus. The structure of the apparatus (e.g., device) may be as follows.

[0054] Figure 2 is a block diagram illustrating embodiments of the device.

[0055] Referring to FIG. 2, the device (200) may include at least one processor (210), a memory (220), and a transmission / reception device (230) that is connected to a network and performs communication. In addition, 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) and communicate with each other.

[0056] The processor (210) can execute program commands stored in at least one of the memory (220) and the storage device (260). The processor (210) may refer to a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor in which the methods according to embodiments of the present disclosure are performed. Each of the memory (220) and the storage device (260) may be configured with at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory (220) may be configured with at least one of a read-only memory (ROM) and a random access memory (RAM).

[0057] 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 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 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 within the cell coverage of the third base station (110-3). The first terminal (130-1) may be within the cell coverage of the fourth base station (120-1). The sixth terminal (130-6) may be within the cell coverage of the fifth base station (120-2).

[0058] Here, each of the plurality of base stations (110-1, 110-2, 110-3, 120-1, 120-2) may be referred to as a NodeB (NB), an evolved NodeB (eNB), a gNB, an advanced base station (ABS), a high reliability-base station (HR-BS), a base transceiver station (BTS), a radio base station, a radio transceiver, an access point, an access node, a radio access station (RAS), a mobile multihop relay-base station (MMR-BS), a relay station (RS), an advanced relay station (ARS), a high reliability-relay station (HR-RS), a home NodeB (HNB), a home eNodeB (HeNB), a road side unit (RSU), a radio remote head (RRH), a transmission point (TP), a transmission and reception point (TRP), etc.

[0059] Each of the plurality of terminals (130-1, 130-2, 130-3, 130-4, 130-5, 130-6) may be referred to as a user equipment (UE), terminal equipment (TE), advanced mobile station (AMS), high reliability-mobile station (HR-MS), terminal, access terminal, mobile terminal, station, subscriber station, mobile station, portable subscriber station, node, device, on board unit (OBU), etc.

[0060] Meanwhile, each of the plurality of base stations (110-1, 110-2, 110-3, 120-1, 120-2) may operate in a different frequency band or may operate in the same frequency band. Each of the plurality of 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 the ideal backhaul link or the non-ideal backhaul link. Each of the plurality of base stations (110-1, 110-2, 110-3, 120-1, 120-2) may be connected to the core network via the ideal backhaul link or the non-ideal backhaul link. Each of the plurality of 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.

[0061] Additionally, each of the plurality of base stations (110-1, 110-2, 110-3, 120-1, 120-2) may support MIMO transmission (e.g., single user (SU)-MIMO, multi user (MU)-MIMO, massive MIMO, etc.), coordinated multipoint (CoMP) transmission, carrier aggregation (CA) transmission, transmission in an unlicensed band, device to device communication (D2D) (or, proximity services (ProSe)), Internet of Things (IoT) 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 scheme, and the fourth terminal (130-4) can receive a signal from the second base station (110-2) by the SU-MIMO scheme. Alternatively, the second base station (110-2) can transmit signals 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 signals from the second base station (110-2) based on the MU-MIMO method.

[0062] 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 scheme, 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) based on the CoMP scheme. Each of the plurality of base stations (110-1, 110-2, 110-3, 120-1, 120-2) can transmit and receive a signal with terminals (130-1, 130-2, 130-3, 130-4, 130-5, 130-6) within its cell coverage based on the CA scheme. 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 under the control of the second base station (110-2) and the third base station (110-3).

[0063] In a communication system (e.g., NR communication system, 6G communication system), the numerology applied to the physical signal and channel can be variable. The numerology can be variable to meet various technical requirements of the communication system. In a communication system to which CP (cyclic prefix)-based OFDM waveform technology is applied, the numerology can 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 can have a relationship of exponentiation of 2 with each other, and the CP length can be scaled at the same rate as the OFDM symbol length. At least some of the numerologies in Table 1 may be supported depending on the frequency band in which the communication system operates. In addition, the communication system may additionally support numerologies not listed in Table 1. Additional CP types (e.g., extended CP) not listed in Table 1 may be supported for specific subcarrier spacing (e.g., 60 kHz).

[0064]

[0065] Below, the frame structure of a communication system will be described. In the time domain, elements (e.g., resource elements) that constitute the frame structure may include subframes, slots, mini-slots, and symbols. A subframe may be used as a unit for transmission, measurement, etc., and the length of a subframe may have a fixed value (e.g., 1 ms) regardless of the subcarrier spacing. A slot may include consecutive symbols (e.g., 14 OFDM symbols). The length of a slot may be variable, unlike the length of a subframe. For example, the length of a slot may be inversely proportional to the subcarrier spacing.

[0066] A slot can be used as a unit for transmission, measurement, scheduling, resource configuration, timing (e.g., scheduling timing, hybrid automatic repeat request (HARQ) timing, channel state information (CSI) measurement and reporting timing, etc.). The length of the actual time resource used for transmission, measurement, scheduling, resource configuration, etc. may or may not match the length of the slot. A minislot can include consecutive symbol(s), and the length of a minislot can be shorter than the length of a slot. A minislot can be used as a unit for transmission, measurement, scheduling, resource configuration, timing, etc. A minislot (e.g., minislot length, minislot boundary, etc.) can be predefined in a technical specification. Alternatively, a minislot (e.g., minislot length, minislot boundary, etc.) can be configured (or instructed) to a terminal. It can be configured (or instructed) to a terminal that a minislot is used when a specific condition is satisfied.

[0067] A base station can schedule a data channel (e.g., a physical downlink shared channel (PDSCH), a physical uplink shared channel (PUSCH), a physical sidelink shared channel (PSSCH)) using some or all of the symbols constituting a slot. In particular, a data channel can be transmitted using a part of a slot for Ultra Reliable Low Latency Communication (URLLC) transmission, unlicensed band transmission, transmission in a situation where NR communication systems and LTE communication systems coexist, analog beamforming-based multi-user scheduling, etc. In addition, the base station can schedule a data channel using a plurality of slots. In addition, the base station can schedule a data channel using at least one mini-slot.

[0068] In the frequency domain, elements that constitute a frame structure may include resource blocks (RBs), subcarriers, etc. One RB may include consecutive subcarriers (e.g., 12 subcarriers). The number of subcarriers constituting one RB may be constant regardless of the numerology. In this case, the bandwidth occupied by one RB may be proportional to the subcarrier spacing of the numerology. An RB may be used as a transmission and resource allocation unit for data channels, control channels, etc. Resource allocation for a data channel may be performed in units of RBs or RB groups (e.g., resource block groups (RBGs)). One RBG may include one or more consecutive RBs. Resource allocation for a control channel may be performed in units of control channel elements (CCEs). In the frequency domain, one CCE may include one or more RBs.

[0069] In a communication system (e.g., an NR communication system), the unit time resource (hereinafter referred to as a "slot") described above may be composed of a combination of one or more of a downlink (DL) interval, a flexible interval (or an unknown interval), and an uplink (UL) interval. Each of the DL interval, the flexible interval, and the UL interval may be composed of one or more consecutive symbols. The flexible interval may be located between a DL interval and an UL interval, between a first DL interval and a second DL interval, between a first UL interval and a second UL interval, etc. When a flexible interval is inserted between a DL interval and a UL interval, the flexible interval may be used as a guard interval.

[0070] A slot may include one or more flexible periods. Alternatively, a slot may not include a flexible period. A terminal may perform a predefined operation in a flexible period. Alternatively, the terminal may perform an operation that is semi-statically or periodically configured by a base station in the flexible period. For example, the operation that is periodically configured by the base station may include a physical downlink control channel (PDCCH) monitoring operation, a synchronization signal block (SSB) reception and measurement operation, a CSI-RS (reference signal) reception and measurement operation, a DL SPS (semi-persistent scheduling) PDSCH reception operation, a sounding reference signal (SRS) transmission operation, a physical random access channel (PRACH) transmission operation, a periodically configured PUCCH transmission operation, a PUSCH transmission operation according to a configured grant (CG), etc. A flexible symbol may be overridden by a DL symbol or an UL symbol. When a flexible symbol is overridden by a DL symbol or an UL symbol, the terminal may perform a new operation instead of the existing operation on the flexible symbol (e.g., the overridden flexible symbol).

[0071] In the present disclosure, SSB may refer to 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 refer to 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 refer to a synchronization signal / physical broadcast channel (SS / PBCH) block. The SSB may be transmitted periodically, and one or more SSB(s) may be repeatedly transmitted in one period. The SSB(s) repeatedly transmitted in one period may be referred to as an SSB burst. Alternatively, SSB(s) transmitted repeatedly in one cycle may be conveniently referred to as SSB.

[0072] The format of a unit time resource (hereinafter referred to as "slot format") can be semi-statically set by higher layer signaling (e.g., radio resource control (RRC) signaling). Information indicating a semi-static slot format can be included in system information, and the semi-static slot format can be set cell-specifically. In addition, the semi-static slot format can be additionally set for each terminal through terminal-specific higher layer signaling (e.g., RRC signaling). A flexible symbol of a cell-specifically set slot format can be overridden to a DL symbol or an UL symbol by terminal-specific higher layer signaling. In addition, the slot format can be dynamically indicated by physical layer signaling (e.g., a slot format indicator (SFI) included in downlink control information (DCI)). A semi-statically set slot format can be overridden by a dynamically indicated slot format. For example, a flexible symbol set to semi-fixed can be overridden by SFI to a DL symbol or an UL symbol.

[0073] A terminal can perform DL operation, UL operation, sidelink operation, etc. in a bandwidth part. A bandwidth part can be defined as a set of consecutive RBs (e.g., physical resource blocks (PRBs)) in a frequency domain having a specific numerology. One numerology can be used for signal transmission (e.g., transmission of a control channel or a data channel) in one bandwidth part. In the present disclosure, "signal" may mean any physical signal and channel when used in a broad sense. A terminal performing an initial access procedure can obtain configuration information of an initial bandwidth part from a base station through system information. A terminal operating in an RRC connected state can obtain configuration information of a bandwidth part from a base station through terminal-specific upper layer signaling.

[0074] The configuration information of the bandwidth portion may include information about the numerology and / or RB set applied to the bandwidth portion. At least one of the bandwidth portion(s) configured for the terminal may be activated. For example, one UL bandwidth portion and one DL bandwidth portion may each be activated within one carrier. In a time division duplex (TDD)-based communication system, a pair of UL bandwidth portions and DL bandwidth portions may be activated. The base station may configure multiple bandwidth portions for the terminal within one carrier and switch the active bandwidth portion of the terminal. The switching of the bandwidth portion may be triggered based on a configuration (e.g., an instruction) from the base station or a timer-based operation of the terminal.

[0075] In embodiments, "a frequency band (e.g., a carrier, a bandwidth portion, a set of RBs, a listen before talk (LBT) subband, a guard band, etc.) is activated" may mean "a base station or a terminal is in a state where it can transmit and receive signals using the frequency band." In addition, "a frequency band is activated" may mean "a state where an RF (radio frequency) filter (e.g., a band-pass filter) of a transceiver is operating including the frequency band."

[0076] In embodiments, RB may mean CRB (common RB). Alternatively, RB may mean PRB or VRB (virtual RB). In a communication system (e.g., NR communication system), CRB may mean RB that constitutes a set of consecutive RBs (e.g., common RB grid) based on a reference frequency (e.g., point A). Carriers, bandwidth portions, etc. may be arranged on the common RB grid. In other words, carriers, bandwidth portions, etc. may be configured as CRB(s). RBs or CRBs that constitute bandwidth portions may be referred to as PRBs, and within bandwidth portions, CRB indices may be appropriately converted to PRB indices. In embodiments, RB may mean IRB (interlace RB).

[0077] The PDCCH can be used to transmit DCI or DCI formats to a terminal. The minimum resource unit constituting the PDCCH can be a resource element group (REG). For example, an REG can be composed 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 PDCCH candidate can be composed of one CCE or aggregated CCEs. A CCE can be composed of multiple REGs. In an NR communication system, CCE aggregation levels 1, 2, 4, 8, and 16 can be supported, and a CCE can be composed of six REGs.

[0078] A CORESET (control resource set) may be a resource region in which a terminal performs blind decoding of a PDCCH. A CORESET may be composed of multiple REGs. A CORESET may be composed 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 consecutive in the time domain. The RBs constituting a CORESET may be consecutive or non-contiguous in the frequency domain. One DCI (e.g., one DCI format, one PDCCH) may be transmitted within a CORESET. Multiple CORESETs may be configured from a cell perspective or a terminal perspective, and the time-frequency resource regions to which the multiple CORESETs are mapped may or may not overlap with each other.

[0079] A CORESET may be set in a terminal during the initial access procedure. For example, a CORESET may be set in a terminal by an initial access signal (e.g., PBCH or system information transmitted via PBCH). The ID (identifier) ​​of the CORESET set by the initial access signal may be 0. The CORESET set by the initial access signal may be referred to as CORESET 0. A terminal operating in an RRC idle state may perform a monitoring operation in CORESET 0 to receive the first PDCCH in the initial access procedure. Not only a terminal operating in an RRC idle state but also a terminal operating in an RRC connected state may perform a monitoring operation in CORESET 0. In addition to system information transmitted via an initial access signal (e.g., PBCH), a CORESET may be set in a terminal by other system information (e.g., SIB1 (system information block type 1)). For example, a terminal may receive SIB1 containing configuration information of CORESET for receiving a random access response (e.g., Msg2). CORESET may be configured in the terminal by terminal-specific higher layer signaling (e.g., RRC signaling).

[0080] A search space may refer to a set of candidate resource regions where PDCCHs can be transmitted. The UE may perform blind decoding on each PDCCH candidate within a predefined search space or a search space established by the base station. The UE may determine whether the PDCCH has been transmitted to itself by performing a cyclic redundancy check (CRC) on the blind decoding results. If the PDCCH is determined to be intended for the UE, the UE may receive the PDCCH.

[0081] One or more search spaces may constitute a search space set. The search spaces may be defined / configured for each CCE aggregation level, and the search space set may refer to a search space for each CCE aggregation level or a sum of search spaces for all CCE aggregation levels. For each CCE aggregation level, the PDCCH candidate may be composed of CCE(s) selected by a predefined hash function within a CORESET or a search space occasion. In an embodiment, the "search space set" may refer to a "search space."

[0082] A search space set can be logically associated (e.g., combined) with one CORESET. One 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 a DCI scheduling a 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 a type 0 PDCCH common search space set or search space set #0. Search space set #0 can be logically associated with CORESET 0.

[0083] The search space set can be divided into a common search space set and a UE-specific search space set depending on the purpose or terminal operation. In the common search space set, common DCI or UE-specific DCI (e.g., UE-specific DCI) can be transmitted, and in the UE-specific search space set (e.g., UE-specific search space set), UE-specific DCI can be transmitted. For example, the common DCI can include resource allocation information of the PDSCH including system information, paging messages, etc., power control commands, slot format indicators (SFIs), and / or preemption indicators. The UE-specific DCI can include resource allocation information of the PDSCH and / or resource allocation information of the PUSCH. Depending on the purpose, multiple DCI formats can be defined, and the multiple DCI formats can be distinguished at the terminal by the DCI payload, DCI fields, DCI sizes, and / or radio network temporary identifiers (RNTIs).

[0084] 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.

[0085] The terminal can assume that the PDCCH DM-RS has a QCL (quasi co-location) relationship with a signal (e.g., SSB, CSI-RS, PDSCH DM-RS, PDCCH DM-RS, etc.). The PDCCH DM-RS can refer to a DM-RS used for modulation and / or demodulation of the PDCCH. The PDSCH DM-RS can refer to a DM-RS used for modulation and / or demodulation of the PDSCH. Since the PDCCH has the same antenna port as the PDCCH DM-RS, the PDCCH and the PDCCH DM-RS can have a QCL relationship with each other. Through the QCL assumption, the terminal can obtain information about the large-scale propagation characteristics of the wireless channel experienced by the PDCCH and PDCCH DM-RS, and can utilize the large-scale propagation characteristics of the wireless channel for channel estimation, reception beamforming, etc. The QCL parameter may include at least one of a delay spread, a Doppler spread, a Doppler shift, an average gain, an average delay, or a spatial Rx parameter. The spatial Rx parameter may correspond to at least one characteristic of a receive beam, a receive channel spatial correlation, or a transmit / receive beam pair. The spatial Rx parameter may be referred to as "spatial QCL." The PDCCH may be used to mean including a PDCCH DM-RS. That the PDCCH has a QCL relationship with a certain signal may mean that the DM-RS of the PDCCH has a QCL relationship with the certain signal. A signal having a QCL relationship with the PDCCH or a resource of the signal may be referred to as a QCL source, a QCL source signal, a QCL source resource, etc.

[0086] PDCCHs transmitted in the same CORESET (e.g., a search space set corresponding to the same CORESET, a PDCCH monitoring occasion, etc.) may have the same QCL relationship. In other words, a unit of a set in which a UE assumes the same QCL may be a CORESET, and the QCL assumptions may be independent for each CORESET. In an embodiment, each of a QCL and a QCL source of a CORESET may mean the QCL and a QCL source of a PDCCH received through the corresponding 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 the search space set may have different QCL relationships.

[0087] The QCL relationship or QCL assumption (e.g., QCL source, QCL type, etc.) of a CORESET can be determined by a predefined method. For example, a UE can assume that a PDCCH DM-RS received through a certain CORESET or a certain search space set has a QCL relationship with respect to an SSB and / or CSI-RS selected during an initial access or random access procedure and a predefined QCL type. A QCL type can mean a set of one or more QCL parameters. The QCL relationship or QCL assumption (e.g., QCL source, QCL type, etc.) of a CORESET can be signaled from a base station to a UE (e.g., RRC signaling, MAC (medium access control) CE (control element) signaling, DCI signaling, a combination of the above signaling, etc.). In other words, the base station can set a transmission configuration information (TCI) state for a CORESET to the UE. In general, a TCI state may include at least one of an ID of a signal having a QCL relationship with a DM-RS of a physical channel to which the TCI is applied (e.g., a PDCCH DM-RS) (e.g., a QCL source of the PDCCH DM-RS, a QCL source resource) or a QCL type for the signal. For example, a base station may configure one or more TCI state candidates for each CORESET to a terminal via RRC signaling, and may indicate (e.g., configure) one TCI state used for CORESET monitoring of the terminal among the one or more TCI state candidates via MAC signaling (or DCI signaling). If there is only one TCI state candidate configured 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 state setting information received from the base station.

[0088] In the present disclosure, the TCI state may be conveniently referred to as TCI. While TCI may generally refer to a broad concept including a beam or signaling information corresponding to a beam, it may be conveniently used in the present disclosure in a meaning corresponding to a beam. DL TCI, or a TCI for DL ​​signal reception, may correspond to a reception beam, and UL TCI, or a TCI for UL signal transmission, may correspond to a transmission beam. A transmission beam may refer to spatial relation information, a transmission spatial filter, etc.

[0089] A terminal may perform an SSB reception operation to camp on a cell or make an initial connection. The terminal may assume that the SSB is transmitted based on a default period (e.g., 20 ms (milliseconds)) during the initial cell search process. After the initial cell search process, the terminal may receive the setting of the SSB period value through system information or an RRC message. In an NR communication system, the maximum period value of the SSB may be 160 ms. Multiple SSBs may be repeatedly transmitted via multiple beams within one period, and the terminal may receive (e.g., attempt to receive) the multiple SSBs based on different receive beams (e.g., different QCL assumptions). The terminal may select one SSB with the best reception quality among one or more SSBs, and perform subsequent transmission and reception procedures based on the selected SSB (e.g., resources, beams, QCL assumptions, etc. of the selected SSB). The terminal may obtain some system information through the SSB. For example, SSB may include PBCH as one component, and the terminal may obtain MIB by receiving PBCH.

[0090] The terminal can perform an initial connection operation, a paging operation, an RLM (radio link monitoring) operation, an RRM (radio resource management) measurement operation, a beam measurement operation, a beam reporting operation, a BFR (beam failure recovery) operation, etc. based on the received SSB. In the present disclosure, the terminal receiving an SSB can be interpreted to mean including the terminal performing the SSB-related operation based on the received SSB.

[0091] A terminal may receive additional system information (e.g., SIB1, SIB) from a base station in addition to some system information (e.g., MIB). For example, the terminal may monitor and receive a PDCCH including scheduling information of a PDSCH in a PDCCH search space set, and may receive a PDSCH including an SIB (e.g., SIB1). The additional system information (e.g., SIB1, SIB) may be transmitted periodically, identically or similarly to SSB transmission. For example, SIB1 may be transmitted at a period of 160 ms, and SIB1 may be repeatedly transmitted multiple times within each period. The period of SIB1 transmission, including repeated transmissions, may coincide with the period of SSB transmission. The above embodiment may mean that the terminal monitors a CORESET (hereinafter referred to as a first CORESET) to which a PDCCH search space set is mapped at the same period as SSB. For example, the first CORESET may be CORESET 0, and the PDCCH search space set associated with CORESET 0 may be a type 0 PDCCH CSS set.

[0092] The first CORESET and / or PDCCH search space set can be configured through some system information (e.g., MIB). For example, the MIB can include configuration information of CORESET 0 and a type 0 PDCCH CSS set, and the PDCCH can be monitored in the type 0 PDCCH CSS set. Since the SIB is cell-specific information, the configuration information for the SIB can be included in a common DCI (e.g., DCI format 1_0), and the common DCI can be transmitted via the PDCCH. The common DCI can have a CRC scrambled by an RNTI (e.g., SI (system information)-RNTI) predefined in the technical specification. The PDCCH and / or the PDSCH can be received based on a QCL relationship with the received SSB.

[0093] Fig. 3a is a conceptual diagram illustrating a first multiplexing pattern of SSB and CORESET, Fig. 3b is a conceptual diagram illustrating a second multiplexing pattern of SSB and CORESET, and Fig. 3c is a conceptual diagram illustrating a third multiplexing pattern of SSB and CORESET.

[0094] Referring to FIGS. 3A to 3C, the SSB and the CORESET can be multiplexed in several forms. The CORESET may refer to the first CORESET or the SIB1 CORESET. The SIB1 CORESET may be a CORESET in which a PDCCH scheduling SIB1 transmission is transmitted and received. In the embodiment of FIG. 3A, the CORESET may be TDM'd with the SSB corresponding to the CORESET. The PDSCH including SIB1 may be multiplexed with the SSB corresponding to the PDSCH based on one of TDM, FDM, or a "combination of TDM and FDM." The above-described multiplexing pattern may be referred to as the first multiplexing pattern. In the embodiment of FIG. 3B, the CORESET may be TDM'd with the SSB corresponding to the CORESET, and the SIB1 PDSCH may be FDM'd with the SSB corresponding to the SIB1 PDSCH. In other words, CORESET can be mapped to different symbols from SSB, and SIB1 PDSCH can be mapped to the same symbols as SSB. The above-described multiplexing pattern can be referred to as a second multiplexing pattern. SIB1 PDSCH can refer to a PDSCH through which SIB1 is transmitted and received. In the embodiment of FIG. 3c, CORESET and SIB1 PDSCH can be FDM'd with SSB corresponding to the CORESET and the SIB1 PDSCH. In other words, CORESET and SIB1 PDSCH can be mapped to the same symbols as SSB. The above-described multiplexing pattern can be referred to as a third multiplexing pattern. The multiplexing pattern supported by the terminal can be different depending on the frequency band or the subcarrier spacing applied to SSB and CORESET. The first multiplexing pattern can be used for a wider frequency range and / or various subcarrier spacings compared to the second and third multiplexing patterns.

[0095] Meanwhile, in cells with low traffic load, the transmission of physical signals for traffic transmission can be minimized. Conventionally, SSB and / or system information can be transmitted periodically based on the same period value (e.g., 20 ms (milliseconds)) regardless of the load level. Even when the traffic load is low, it may be difficult for the base station to operate in a low-power mode for a long time. In the present disclosure, methods for dynamically controlling SSB transmission to save network power will be proposed. Saving network power can mean saving network energy. According to the proposed method, several parameters defining SSB transmission can be controlled by the base station. For example, the SSB transmission period (e.g., SSB period) can be controlled by the base station. The base station can dynamically control the SSB transmission period depending on the traffic load. SSB can be transmitted based on a first period value when the traffic load is high. SSB can be transmitted based on a second period value when the traffic load is low (or when there is no traffic load). The first period value may be set to an appropriate value that ensures the performance of the SSB-related operations of the terminal described above. The second period value may be set to a value greater than the first period value. When the cell load (e.g., traffic load) is low, the base station can intermittently transmit SSB based on the second period value, maximizing the sleep time of the base station while tolerating a certain degree of performance degradation of the terminal operation. Consequently, the power efficiency of the network can be increased.

[0096] In the present disclosure, a base station may refer to a base station that manages cell(s) or any cell(s) included in a base station. A cell may refer to a cell included in a base station, a base station that includes a cell, or a base station that manages a cell. For example, when a terminal transmits and receives a signal to and from a cell, it may refer to the terminal transmitting and receiving a signal to and from a base station that includes the cell. The cell may refer to a cell that performs communication with the terminal, a cell on which the terminal has camped, a cell on which the terminal attempts initial connection, etc. For a terminal in RRC idle / inactive mode, a cell may refer to a cell on which the terminal has camped or a cell on which the terminal is likely to camp. For a terminal in RRC connected mode, a cell may refer to a serving cell, a neighboring cell, a cell that performs RRM measurement, a cell on which the terminal has accessed, a cell (e.g., a carrier) on which the terminal maintains an access state, etc. In the present disclosure, terminals performing communication with a base station may all be considered: terminals in RRC idle mode, terminals in RRC inactive mode, and terminals in RRC connected mode.

[0097] In embodiments, a cell performing SSB dynamic adaptation operation may be a cell supporting low power mode operation. A cell performing SSB dynamic adaptation operation may be conveniently referred to as a network energy saving (NES) cell. In the present disclosure, a cell may mean a NES cell. When a cell periodically transmits SSB and / or system information (e.g., SIB1), this may mean that, from a terminal perspective, the terminal performs an operation of periodically receiving (e.g., monitoring) the SSB and / or system information (e.g., SIB1). When the terminal receives (e.g., monitors) system information (e.g., SIB1), this may mean that the terminal receives (e.g., monitors) a DL signal (e.g., PDSCH) including the system information (e.g., SIB1) and / or a DL signal (e.g., PDCCH) scheduling the DL signal. The base station may omit an operation of transmitting SSB or SIB1 in a part of SSB resources or SIB1 resources that are periodically configured as needed. A terminal performing the operations described in the present disclosure may be conveniently referred to as an NES terminal. From the perspective of SSB reception operations, an NES terminal can be distinguished from a legacy terminal. In the present disclosure, a terminal may be interpreted as an NES terminal or a legacy terminal depending on the context. SSB adaptation may mean changing (e.g., adjusting, controlling) the period (e.g., period value) of an SSB. The period (e.g., period value) of an SSB can be dynamically changed (e.g., adjusted, controlled).

[0098] In this disclosure, several scenarios can be considered depending on whether legacy terminals coexist. As a first scenario, a cell can be considered in which legacy terminals in RRC idle / inactive mode coexist with NES terminals. If camping of the legacy terminals is permitted, SSBs can be transmitted at a default period (e.g., 20 ms) for the initial connection of the legacy terminals. The SSB period for the legacy terminals (e.g., the SSB period value) can be set by a legacy parameter. Changing the SSB period to a value greater than the default period may adversely affect the operation of the legacy terminals. In this case, the use of SSB dynamic adaptation may be limited. The above-described scenario may be referred to as the first scenario.

[0099] As a second scenario, a scenario in which there are no legacy UEs in RRC idle / inactive mode in the NES cell can be considered. For example, the base station can block legacy UEs in RRC idle / inactive mode from camping on a specific cell (e.g., the NES cell) by broadcasting a cell barring message, etc. The cell barring message can be included in system information (e.g., MIB, SIB1, etc.) and transmitted periodically. In this scenario, it may be unnecessary to transmit SSB at a mandatory default period, and the SSB transmission period can be changed regardless of the legacy operation of the UE. The above-described scenario may be referred to as the second scenario.

[0100] In the following examples, the second scenario, which has a minimal impact on legacy terminals, will be primarily considered. However, the proposed method can be applied generally regardless of specific scenarios or the presence or absence of legacy terminals. In other words, the proposed method can be applied to the first and / or second scenarios. After establishing an RRC connection for a legacy terminal, a period other than the default period for SSB transmission can be reconfigured for the legacy terminal. Therefore, the coexistence of legacy terminals in RRC connection mode in a cell may not be a problem when applying the proposed SSB dynamic adaptation method to the first and / or second scenarios.

[0101] Figure 4 is a conceptual diagram illustrating an embodiment of an SSB dynamic adaptation method.

[0102] Referring to FIG. 4, the transmission period of an SSB transmitted in a cell can be dynamically changed. For example, the SSB period value can be changed from a first period value to a second period value. In the present disclosure, an SSB may mean an SSB burst, and an SSB burst may include N SSBs. N may be a natural number. A maximum number (M) of SSBs that can be transmitted in one period for each frequency band and M SSB resources corresponding to the maximum number (M) of SSBs that can be transmitted may be defined. M may be a natural number. A base station may select N SSB resources from among the M SSB resources, and may actually transmit N SSBs in the selected N SSB resources. A terminal may check the N SSB resources based on SIB1 or an RRC message (e.g., ssb-PositionInBurst) received from the base station. In the embodiment of FIG. 4, N may be 4. A base station can transmit a configuration / control message to a terminal, and instruct the terminal to receive or monitor SSB at a changed cycle. The configuration / control message can indicate a changed cycle of SSB. The configuration / control message can instruct the terminal to receive or monitor SSB at the changed cycle. In the present disclosure, the configuration / control message may be conveniently referred to as an SSB adaptation indicator (e.g., an SSB adaptation indicator). The SSB adaptation indicator can indicate SSB adaptation indication information to the terminal. Depending on the context, the SSB adaptation indicator may mean SSB adaptation indication information.

[0103] The SSB adaptation indicator can be transmitted to the terminal by a dynamic signaling procedure. For example, the SSB adaptation indicator can be transmitted to the terminal by a physical layer signaling procedure (e.g., DCI), a higher layer signaling procedure (e.g., MAC CE), or a combination of the above procedures. The SSB adaptation indicator can belong to a specific field of the DCI or MAC CE. The SSB adaptation indication information can be mapped to a code point, a bitmap, consecutive bit(s), etc. of a specific field and indicated to the terminal. The SSB adaptation indication information can be configured (e.g., indicated) to the terminal by a semi-static signaling procedure (e.g., SIB, cell-specific RRC signaling, UE-specific RRC signaling). In the above embodiment, the terminal can receive configurations for the first period value and the second period value through the semi-static signaling, and can receive dynamic signaling indicating to apply one of the first period value and the second period value (e.g., the second period value).

[0104] According to one embodiment, the SSB adaptation indication information may include at least information about an SSB period value. In the above embodiment, the SSB adaptation indication may indicate at least a second period value of the SSB to the terminal. To support the above-described operation, the base station may set one or more period values ​​for the SSB to the terminal in advance. Each of the plurality of period values ​​for the SSB may have a unique index. The SSB adaptation indication information may include an index corresponding to the SSB period value to be indicated. The plurality of period values ​​may be included in the configuration information of each SSB (e.g., an SSB burst). In other words, one SSB configuration may include multiple period values. The SSB configuration may be indicated (e.g., transmitted) to the terminal by higher layer signaling (e.g., system information, UE-specific RRC signaling).

[0105] A default period value of SSB can be defined. For example, the default period value of SSB can be 20ms. If the terminal does not receive a setting of the period value of SSB or if a predetermined condition related to SSB operation is satisfied, the terminal can receive SSB based on the default period value. For example, when a bandwidth portion (e.g., a DL bandwidth portion) interrelated with SSB is activated or when a bandwidth portion interrelated with SSB is activated for the first time, the terminal can receive SSB based on the default period value. If the terminal does not receive an SSB adaptation instruction for a long period of time (e.g., for a predefined time or a pre-set time), the terminal can switch or maintain the period value of the SSB to the default period value. In the present disclosure, the predefined time or the pre-set time may be referred to as a duration during which the SSB adaptation instruction is valid. Specific operations related to the duration will be described later.

[0106] The default period value of SSB may not be separately configured for the terminal. The index of the default period value of SSB may be predefined as a fixed value. For example, the index of the default period value of SSB may be 0, and the indices of other period value(s) configured for the terminal may be sequentially assigned from 1. The other period value(s) configured for the terminal may include a value greater than the default period value of SSB and / or a value less than the default period value of SSB. A period value less than the default period value of SSB (e.g., 5 ms, 10 ms) may be used for purposes other than NES (e.g., to improve SSB measurement performance). The default period value of SSB may be applied to CD-SSB (cell defining-SSB). The default period value of SSB may not be applied to NCD-SSB (non-cell defining-SSB). The default period value of SSB may be signaled from the base station to the terminal. The default period value of SSB may be included in the SSB configuration information. Other cycle values ​​besides the default cycle value of the SSB may have values ​​less than and / or greater than the default cycle value. Considering the above-described operation, the default cycle value may be referred to as the base cycle value, the first used cycle value, the first active cycle value, etc.

[0107] The multiple periodic values ​​configured in the SSB can be configured based on different RRC parameters. The multiple periodic values ​​configured in the SSB can include a legacy periodic value configured by a legacy parameter and additional periodic value(s) configured by a new parameter (e.g., an additional parameter). The legacy periodic value can be configured for a legacy terminal and / or a NES terminal. The additional periodic value(s) can be configured for a NES terminal. The legacy periodic value can be used as a default periodic value. The legacy periodic value can be configured with a time offset. The minimum unit of the time offset can be a half radio frame or 5 ms. The time offset to be applied to the additional periodic value may not be separately defined. The time offset configured with the legacy periodic value can be equally applied to the additional periodic value. Alternatively, the time offset may not be applied to an SSB burst to be received based on the additional periodic value. In other words, the time offset for the additional periodic value can be 0. According to the above-described method, SSB resource sets formed by multiple period values ​​may have an inclusive relationship with each other. For example, SSB resources formed by long period values ​​may be a subset of SSB resources formed by short period values. Based on the above-described embodiment, even if the SSB period value is dynamically changed, the terminal can monitor (e.g., receive) the SSB based on one SMTC (SSB measurement time configuration) window. The period value of the one SMTC window may be set to match any period value of the SSB. For example, the period value of the one SMTC window may match the shortest period value of the SSB. Alternatively, the period value of the one SMTC window may be defined as the above-described default period value. Alternatively, a separate time offset for an additional period value may be set in the terminal.In the above situation, if an additional period value is dynamically indicated to the terminal by DCI or MAC CE, the SSB can be received in a time resource determined based on the indicated additional period value and a time offset corresponding to the additional period value. In other words, the base station can transmit the SSB in a time resource determined based on the additional period value and the time offset, and the terminal can receive the SSB in a time resource determined based on the additional period value and the time offset.

[0108] In another embodiment, a terminal may receive one or more SSB configuration(s) from a base station for one SSB (e.g., an SSB burst). Each SSB configuration may include one or more parameter(s) defining an SSB operation. Each SSB configuration may include at least an SSB period value. In addition to the SSB period value, each SSB configuration may further include at least one of information regarding the frequency location of the SSB, an SSB transmission pattern, or a time domain offset of the SSB (e.g., a half radio frame to which the SSB is mapped). For example, the terminal may receive a first SSB configuration and a second SSB configuration through semi-static signaling, and may receive dynamic signaling instructing to receive an SSB by applying one of the first SSB configuration and the second SSB configuration. Each SSB configuration may have a unique index. The multiple SSB configurations may include different SSB period values, and the SSB period may be dynamically controlled by dynamically changing the SSB configuration. A default SSB configuration may be defined. The default SSB configuration may include the default period value described above. The default SSB configuration may further include at least one of the frequency location information of the SSB acquired by the terminal through the system information of the cell, the transmission pattern of the SSB, or the SSB time domain offset (e.g., the half radio frame to which the SSB is mapped). The index of the default SSB configuration may be defined as a fixed value (e.g., 0). The default SSB configuration may be applied to CD-SSB. In the following embodiments, a plurality of SSB period values ​​may correspond to a plurality of SSB configurations, and an operation of adapting the SSB period based on the plurality of SSB period values ​​may correspond to an operation of adapting the SSB period based on a plurality of SSB period values ​​included in the plurality of SSB configurations.

[0109] Meanwhile, multiple SSBs can be transmitted in one cell or one carrier. Among the SSBs transmitted in a cell, an SSB associated with system information of the cell (e.g., SIB1, RMSI (remaining minimum system information)) can be referred to as a CD-SSB. The MIB transmitted through the CD-SSB can indicate configuration information of a CORESET 0 and a Type 0-PDCCH CSS set to the terminal, and the terminal can monitor the PDCCH based on the configuration information, and can obtain scheduling information of a PDSCH including SIB1 based on the PDCCH. A PDCCH that schedules a PDSCH including SIB1 can be referred to as a SIB1 PDCCH for convenience. A PDSCH including SIB1 can be referred to as a SIB1 PDSCH for convenience. At least a CD-SSB can be transmitted in a PCell (primary cell), and a reference frequency (e.g., a center frequency) of the CD-SSB can be mapped onto a sync raster. NCD-SSBs can be mapped to either the synchronous raster or a non-synchronous raster frequency location. In an SCell, CD-SSBs can be mapped to a non-synchronous raster frequency location. CD-SSBs mapped to a non-synchronous raster frequency can be distinguished from CD-SSBs mapped to the synchronous raster in terms of SSB adaptation operation. For example, CD-SSBs mapped to the synchronous raster can be transmitted at a fixed period to support initial access of a terminal, while CD-SSBs mapped to a non-synchronous raster frequency can be dynamically adapted to save network power. In other words, the period of CD-SSBs mapped to a non-synchronous raster frequency can be dynamically changed. Simultaneously or separately from the above-described embodiments, CD-SSBs mapped to a non-synchronous raster frequency can be treated identically or similarly to NCD-SSBs.In other words, in the embodiments, NCD-SSB may be interpreted as including CD-SSB mapped to a frequency other than the synchronous raster, and the method applied to NCD-SSB may be applied identically or similarly to CD-SSB mapped to a frequency other than the synchronous raster.

[0110] An SSB that is not associated with system information of a cell (e.g., SIB1, RMSI) may be referred to as a NCD-SSB. The terminal may receive a configuration of an NCD-SSB for a portion of a DL bandwidth that does not include a CD-SSB, and may perform at least one of an RLM operation, an RRM measurement operation, a BFR operation, or a measurement operation for random access resource selection based on the NCD-SSB. At least for the first multiplexing pattern of SSB and CORESET, the initial portion of the DL bandwidth may include a CD-SSB, and the communication node (e.g., a base station and / or a terminal) may operate based on the CD-SSB.

[0111] The UE may not assume that the SSB is transmitted together with SIB1 in the SCell. Strictly speaking, the CD-SSB may not exist in the SCell. For convenience, the SSB configured based on cell-specific configuration information in the SCell may be referred to as a CD-SSB. For example, the configuration information of the CD-SSB in the SCell may be included in the RRC parameter (e.g., the information element (IE)) servingCellConfigCommon. The CD-SSB in the SCell may not be correlated with any DL bandwidth portion. For example, in the SCell, the CD-SSB may not be associated with the initially active DL bandwidth portion, and the CD-SSB may be transmitted within or outside the initially active DL bandwidth.

[0112] From the perspective that the UE does not receive SIB1 associated with the SSB transmitted on the SCell, all SSBs transmitted on the SCell can be considered as non-CD-SSBs (e.g., NCD-SSBs). Non-CD-SSBs may be referred to as NCD-SSBs for convenience. SSBs of the SCell may include cell-specific SSBs and UE-specific SSBs. Cell-specific SSBs may be configured by cell-specific configuration information of the SCell (e.g., servingCellConfigCommon). UE-specific SSBs may be configured by UE-specific configuration information of the SCell (e.g., UE-specific RRC messages). Cell-specific SSBs may not be correlated with a specific DL bandwidth segment, and UE-specific SSBs may be correlated with a specific DL bandwidth segment. UE-specific SSBs may be referred to as bandwidth segment-specific SSBs. In the present disclosure, UE-specific SSB and bandwidth portion-specific SSB may be used interchangeably in SCell. If an activated DL bandwidth portion includes a cell-specific SSB (e.g., a cell-specific NCD-SSB), the UE may receive the cell-specific SSB in the DL bandwidth portion. If a DL bandwidth portion that is correlated with a UE-specific SSB (e.g., a UE-specific NCD-SSB) is activated, the UE may receive the UE-specific SSB (e.g., a UE-specific NCD-SSB). The UE may receive either a cell-specific SSB or a UE-specific SSB in a SCell in a given time interval. In the present disclosure, unless otherwise stated, CD-SSB and NCD-SSB may respectively correspond to cell-specific SSB and UE-specific SSB in an SCell.

[0113] Alternatively, for a SCell, all SSBs may be configured to correlate with at least one DL bandwidth segment. Cell-specific SSBs may also correlate with specific DL bandwidth segments. For example, a cell-specific SSB may correlate with at least the first active DL bandwidth segment in the SCell. Only specific SSBs (e.g., cell-specific SSBs) may be allowed to correlate with multiple DL bandwidth segments, while the remaining SSBs (e.g., UE-specific SSBs) may be restricted to correlate with only one DL bandwidth segment.

[0114] The terminal may receive SSB configuration information including a plurality of SSB period values ​​for each of the CD-SSB and the NCD-SSB (e.g., for each of the cell-specific SSB and the UE-specific SSB). Alternatively, the terminal may receive a plurality of SSB configurations (e.g., CD-SSB configurations) for the CD-SSB and may receive information indicating to apply one (e.g., at least one) of the plurality of SSB configurations. The terminal may receive a plurality of SSB configurations (e.g., NCD-SSB configurations) for the NCD-SSB. In an embodiment, the terminal may receive a plurality of NCD-SSB configurations for one DL bandwidth portion and may receive information indicating to apply one (e.g., at least one) of the plurality of NCD-SSB configurations. In other words, for each DL bandwidth portion, the NCD-SSB configuration and / or one NCD-SSB configuration for each DL bandwidth portion may not be configured (e.g., indicated) to the terminal, and for each DL bandwidth portion, multiple NCD-SSB configurations may be configured (e.g., indicated) to the terminal. One DL bandwidth portion may be correlated with multiple NCD-SSB configurations, and the terminal may receive an NCD-SSB in the DL bandwidth portion based on one of the NCD-SSB configurations correlated with the DL bandwidth portion. NCD-SSB configurations correlated with the same DL bandwidth portion may be grouped. CD-SSB configurations may be grouped. The SSB adaptation instruction may be performed in units of SSB configuration groups (e.g., SSB groups). In the embodiments below, each SSB may correspond to an SSB configuration group. Configuring multiple SSBs in the terminal may mean that multiple SSB configuration groups (e.g., SSB groups) are configured in the terminal. An SSB index may correspond to an SSB configuration group index or an SSB group index.Multiple SSB settings within each SSB setting group may contain different SSB cycle values. The SSB cycle can be adapted by dynamically changing the SSB settings within each SSB setting group.

[0115] FIG. 5 is a conceptual diagram illustrating an embodiment of a method for receiving SSB in a terminal in RRC idle / inactive mode.

[0116] Referring to FIG. 5, the downlink operation of a terminal in RRC idle / inactive mode can be performed based on a CD-SSB on an initial DL bandwidth portion. The terminal can assume a default period in an initial cell search procedure and acquire a CD-SSB based on the assumption. In the above-described procedure, the terminal can find out the frequency location and time domain offset of the CD-SSB. The terminal can acquire the remaining configuration information, including the actual period, transmission pattern, etc. of the CD-SSB, based on the configuration information included in SIB1 associated with the CD-SSB. Based on the above-described method, the transmission period of the CD-SSB assumed by the terminal in RRC idle / inactive mode can be dynamically changed.

[0117] A UE in RRC idle / inactive mode can monitor the CSS set associated with CORESET 0 for PDCCH reception. The SSB adaptation indicator can be included in common DCI or group common DCI, and the SSB adaptation indicator can be transmitted to the UE through the CSS set. Alternatively, the SSB adaptation indicator can be included in a MAC CE, and the MAC CE including the SSB adaptation indicator can be transmitted to the UE through a PDSCH scheduled by the common DCI or group common DCI. In other words, the SSB adaptation indicator can be included in the PDSCH.

[0118] Since a terminal in RRC idle / inactive mode receives a CD-SSB, reception of an NCD-SSB in the terminal may be unnecessary. "If the initial DL bandwidth portion configured via SIB1 does not include a CD-SSB, a specific multiplexing pattern of SSB and CORESET (e.g., the second multiplexing pattern illustrated in FIG. 3b and / or the third multiplexing pattern illustrated in FIG. 3c) is used, and the terminal is a RedCap (reduced capability) terminal," the terminal can expect to receive an NCD-SSB configuration on the initial DL bandwidth portion even though it is in an RRC idle state. The terminal can perform the above-described SSB-related operations based on the NCD-SSB. The terminal may be a terminal that does not support a frequency hopping operation to an area to which a CD-SSB is mapped. In this case, the SSB adaptation indicator can control the NCD-SSB configured in the terminal. In other words, a terminal in RRC idle / inactive mode can determine an assumption about the NCD-SSB transmission period based on the SSB adaptation indicator.

[0119] FIG. 6 is a conceptual diagram illustrating an embodiment of an SSB reception method in a terminal in RRC connection mode, and FIG. 7 is a conceptual diagram illustrating an embodiment of an SSB reception method in a terminal in RRC connection mode.

[0120] Referring to FIGS. 6 and 7, a downlink operation of a terminal in RRC connection mode can be performed in an active DL bandwidth portion. The active DL bandwidth portion can be an initial DL bandwidth portion or a DL bandwidth portion additionally configured in the terminal. According to the embodiment of FIG. 6, the active DL bandwidth portion can include a CD-SSB, and the terminal can perform an SSB-related operation based on the CD-SSB. According to the embodiment of FIG. 7, the active DL bandwidth portion can not include a CD-SSB. In this case, the terminal can receive an NCD-SSB configuration for the active DL bandwidth portion, and perform an SSB-related operation based on the NCD-SSB.

[0121] Fig. 8 is a conceptual diagram illustrating an embodiment of a method for receiving SSB in a terminal in RRC connection mode.

[0122] Referring to FIG. 8, a terminal may receive configurations of multiple DL bandwidth portions including a first DL bandwidth portion and a second DL bandwidth portion. The first DL bandwidth portion may include a CD-SSB, and the second bandwidth portion may not include a CD-SSB. The terminal may receive a NCD-SSB configuration for the second DL bandwidth portion. For example, the first DL bandwidth portion may be an initially active DL bandwidth portion. The terminal may perform a bandwidth portion switching operation between the first DL bandwidth portion and the second DL bandwidth portion based on the above-described method. The terminal may receive a CD-SSB in a section in which the first DL bandwidth portion is activated, and may receive a NCD-SSB in a section in which the second DL bandwidth portion is activated. As the bandwidth portions are switched, an SSB received by the terminal in the first DL bandwidth portion may dynamically change from a CD-SSB to an NCD-SSB, and an SSB received by the terminal in the second DL bandwidth portion may dynamically change from an NCD-SSB to a CD-SSB.

[0123] According to the above embodiments, a terminal in RRC connection mode can receive configurations of multiple SSBs for a single serving cell, and can receive one SSB corresponding to an activated DL bandwidth portion. The one SSB may be a CD-SSB or an NCD-SSB. The CD-SSB may be a broadcast signal commonly transmitted to terminals. The NCD-SSB may be configured UE-specifically in association with each DL bandwidth portion.

[0124] According to the proposed method, both CD-SSB transmission and NCD-SSB transmission can be dynamically controlled. A terminal can receive configurations for both CD-SSB and NCD-SSB for a single cell, and dynamically change the transmission cycle of the CD-SSB and the transmission cycle of the NCD-SSB based on an SSB adaptation indicator. The transmission cycle of the CD-SSB and the transmission cycle of the NCD-SSB can be independently controlled. Alternatively, a common cycle value can be used for the transmission of the CD-SSB and the transmission of the NCD-SSB, and the common cycle value can be dynamically controlled. Specific methods and embodiments for dynamically controlling multiple SSBs will be described below.

[0125] As a first method of controlling multiple SSBs, the multiple SSBs (e.g., CD-SSB and NCD-SSB) can be controlled by different signaling procedures. The above-described method may be referred to as (method 100). According to one embodiment, the CD-SSB can be controlled by a common control message, and the common control message can be transmitted to the terminal by a broadcast signal or a groupcast signal. The common control message can mean DCI, a specific field of DCI, MAC CE, etc., and the broadcast / groupcast signal can be common DCI, group common DCI, a PDCCH including the DCI, or a PDSCH scheduled by the DCI. In a communication system, the common DCI or group common DCI can mean DCI format 1_0, DCI format 0_0, DCI format 2_X (X=0, 1, 2, ...), DCI received from a CSS set, etc. The NCD-SSB can be controlled by a UE-specific control message, and the UE-specific control message can be transmitted to a specific terminal by a UE-specific signal. The UE-specific control message can be DCI, a specific field of DCI, MAC CE, etc., and the UE-specific signal can be UE-specific DCI, a PDCCH including the DCI, or a PDSCH scheduled by the DCI. In a communication system, the UE-specific DCI can mean scheduling DCI, DCI format 1_X (X=1, 2, 3, ...), DCI format 0_X (X=1, 2, 3, ...), DCI received from a set of USSs, etc.

[0126] According to the above embodiment, the terminal can distinguish the SSB to which the SSB adaptation indication is to be applied through the signaling procedure used in the SSB adaptation indication. In the case of physical layer signaling, the signaling procedure may mean a DCI type, a DCI format, a search space set type, a CORESET, etc. In other words, the signaling procedure may be distinguished by the DCI type, the DCI format, the search space set type, and / or the CORESET, and the SSB to which the SSB adaptation indication is to be applied may be distinguished by the DCI type, the DCI format, the search space set type, and / or the CORESET used in the SSB adaptation indication. If the SSB adaptation indication information is received based on the common DCI or the group common DCI, the terminal can apply the received SSB adaptation indication information to the CD-SSB. If the SSB adaptation indication information is received based on the UE-specific DCI, the terminal can apply the received SSB adaptation indication information to the NCD-SSB.

[0127] Simultaneously or separately from the above-described embodiments, the SSB to which the SSB adaptation indication is applied may be determined based on the DL bandwidth portion. For example, the terminal may apply the received SSB adaptation indication information to an SSB (e.g., NCD-SSB) that is correlated with the currently activated DL bandwidth portion. Considering dynamic bandwidth portion switching, the meaning of "currently activated" may be interpreted in one of several ways. In a first way, the currently activated DL bandwidth portion may mean the DL bandwidth portion that is activated at the time the SSB adaptation indication is received (e.g., the slot in which the DCI or PDSCH is received). In a second way, the currently activated DL bandwidth portion may mean the DL bandwidth portion that is activated at the time the SSB adaptation indication is applied.

[0128] When the SSB adaptation instruction is applied only to a preset time duration, the currently activated DL bandwidth portion may mean a DL bandwidth portion that includes the time duration. When the time duration is included in a plurality of activated DL bandwidth portions (e.g., a previously activated DL bandwidth portion and a DL bandwidth portion newly activated by the bandwidth portion switching instruction) by bandwidth portion switching, the former DL bandwidth portion (e.g., the previously activated DL bandwidth portion) may be regarded as the currently activated DL bandwidth portion. In other words, when the time duration is partially included in each of the previously activated DL bandwidth portion and the newly activated DL bandwidth portion, the former DL bandwidth portion (e.g., the previously activated DL bandwidth portion) may be regarded as the currently activated DL bandwidth portion. In other words, the bandwidth portion that includes a starting point (e.g., a certain starting interval) of the time duration may be regarded as the currently activated DL bandwidth portion. Alternatively, the SSB adaptation indication may be applied to both the first SSB received in the previously activated DL bandwidth portion and the second SSB received in the indicated active DL bandwidth portion. The first SSB and the second SSB may be the same SSB. Alternatively, the first SSB and the second SSB may be different SSBs that may commonly follow the SSB adaptation indication and to which the same periodic value is applied. For example, when multiple SSBs are configured for a specific cell (e.g., SCell) of the terminal, one SSB periodic value indicated to the terminal may be commonly applied to the multiple SSBs (e.g., all the SSBs) regardless of the bandwidth portion(s) to which the multiple SSBs belong or the bandwidth portion(s) to which the multiple SSBs are interconnected.Alternatively, if the proposed SSB adaptation indication method is used, dynamic bandwidth partial switching operation may not be used. The terminal may not expect bandwidth partial switching (e.g., dynamic bandwidth partial switching by DCI, bandwidth partial switching by timer expiration) to occur during the duration in which the SSB adaptation indication is applied.

[0129] SSB adaptation indication information may be included in scheduling DCI (e.g., DCI format 1_X / 0_X). If NCD-SSB (or UE-specific SSB in SCell) is configured in a bandwidth portion (e.g., DL bandwidth portion) indicated by scheduling DCI, the UE may apply the SSB adaptation indication to the NCD-SSB (or UE-specific SSB in SCell). If NCD-SSB (or UE-specific SSB in SCell) is not configured in a bandwidth portion (e.g., DL bandwidth portion) indicated by scheduling DCI, the UE may apply the SSB adaptation indication to CD-SSB (or cell-specific SSB in SCell). In other words, the SSB adaptation indication may be applied to an SSB received in a DL bandwidth portion activated by DCI including SSB adaptation indication information.

[0130] According to the above embodiment, the terminal can identify (e.g., determine) the SSB to which the SSB adaptation indication is to be applied based on the signaling procedure and / or the DL bandwidth portion without separate explicit configuration information (e.g., SSB index, SSB type) indicating the SSB to which the SSB adaptation indication is to be applied. Therefore, the amount of information of the SSB adaptation indication information can be minimized. The SSB adaptation indicator can include adaptation indication information for at most one SSB, and the base station can transmit multiple SSB adaptation indicators to the terminal through multiple signalings when it wants to control transmission of multiple SSBs. It may be difficult to dynamically control other SSBs (e.g., another NCD-SSB) other than the NCD-SSB that is correlated with the DL bandwidth portion activated in the terminal. Since the terminal in RRC idle / inactive mode cannot receive the dynamic control message of the NCD-SSB, even if the period of the NCD-SSB is changed, the changed period may not be reflected in the operation of the terminal.

[0131] As a second method for controlling multiple SSBs, multiple SSBs (e.g., CD-SSB and NCD-SSB) can be controlled by the same signaling procedure. The above-described method may be referred to as (method 200). A physical layer signaling procedure may be considered for the above-described method. The CD-SSB and the NCD-SSB can be controlled based on the same DCI format and / or the same search space set. The CD-SSB adaptation indication information and the NCD-SSB adaptation indication information can be indicated together or separately by the same DCI field. Alternatively, the CD-SSB and the NCD-SSB can be controlled by the same MAC CE, and the PDSCH including the MAC CE can be scheduled to the UE based on the same DCI format, the same search space set, etc.

[0132] Meanwhile, when a cell transmitting multiple SSBs wants to operate in NES mode, it is desirable that the transmission periods of the multiple SSBs be controlled simultaneously, if possible. For example, when the traffic load of the cell is low, it is desirable that the cell performs the NES operation by collectively changing the transmission periods of the multiple SSBs to a long period. According to an embodiment considering the above-described operation, the base station can control multiple SSBs set to a terminal with a single signaling. The multiple SSBs may be SSBs set to one cell or SSBs set to multiple cells. For example, for one serving cell, the transmission period of a first SSB received in a currently activated DL bandwidth portion and the transmission period of a second SSB interrelated with a different DL bandwidth portion (or, a different time interval) may be controlled together for the terminal. Alternatively, carrier aggregation for multiple serving cells (e.g., carriers) may be configured for the terminal, and the transmission period of the first SSB received in the first serving cell and the transmission period of the second SSB received in the second serving cell may be jointly controlled for the terminal. Even if the terminal is not currently receiving the second SSB, the transmission parameters of the second SSB may be preemptively jointly controlled. The first SSB and the second SSB may correspond to the CD-SSB and the NCD-SSB, respectively. Alternatively, the first SSB and the second SSB may correspond to the NCD-SSB and the CD-SSB, respectively. Alternatively, the first SSB and the second SSB may correspond to different NCD-SSBs, respectively. In the SCell, the first SSB and the second SSB may be a cell-specific SSB and a UE-specific SSB, respectively. Alternatively, in the SCell, the first SSB and the second SSB may be a plurality of UE-specific SSBs that are interrelated with different DL bandwidth portions. Alternatively, the first SSB and the second SSB may be different CD-SSBs transmitted from different serving cells.If both serving cells to which the first SSB and the second SSB are transmitted are SCells, the first SSB and the second SSB may be non-CD-SSB SSBs or NCD-SSBs. Alternatively, the first SSB and the second SSB in the SCell may not be distinguished as CD-SSBs and NCD-SSBs. For a UE in RRC idle / inactive mode, the first SSB and the currently activated DL bandwidth portion may be CD-SSBs and initial DL bandwidth portions, respectively, and the second SSB may be NCD-SSBs. Some of the plurality of SSBs may be on-demand SSBs. For example, the first SSB and the second SSB may correspond to periodic SSBs and on-demand SSBs, respectively.

[0133] Considering the characteristics of the NCD-SSB described above, UE-specific signaling (e.g., DCI format 0_X, DCI format 1_X, scheduling DCI) may be used as signaling for the NCD-SSB. For example, an SSB adaptation indicator may be included in a specific field of the scheduling DCI, and the scheduling DCI may be transmitted to the UE through a USS set or a CSS set. Each SSB may be assigned a unique index (e.g., an SSB index), and multiple SSBs may be distinguished by different indices. Alternatively, as in the embodiment described above, each SSB configuration group (e.g., an SSB group) may be assigned a unique index (e.g., an SSB configuration group index or an SSB group index), and multiple SSB configuration groups (e.g., multiple SSB groups) may be distinguished by different indices. According to one embodiment, N indices may be assigned to N SSBs including a CD-SSB (or a cell-specific SSB in an SCell). N can be a natural number. The N indices can be numbered in ascending order from 0. The index of the CD-SSB (or cell-specific SSB in SCell) can be defined as 0. According to another embodiment, M indices can be assigned to M SSBs (or UE-specific SSBs in SCell) excluding the CD-SSB (or cell-specific SSB in SCell), and the M indices can be numbered in ascending order from 0. M can be a natural number. In this case, the CD-SSB (or cell-specific SSB in SCell) can be distinguished from the NCD-SSB(s) by a method other than the index. As an explicit distinguishing method, a flag for distinguishing the CD-SSB (or cell-specific SSB in SCell) from the NCD-SSB can be included in the SSB indication information.If the CD-SSB (or cell-specific SSB in SCell) is not included in the multiple SSBs or multiple SSB configuration groups, the index may be sequentially numbered for the multiple SSBs or multiple SSB configuration groups. Alternatively, the index of the CD-SSB (or cell-specific SSB in SCell) may also be explicitly included in the configuration information of the SSB, and the configuration information of the SSB including the index of the CD-SSB (or cell-specific SSB in SCell) may be transmitted from the base station to the terminal.

[0134] An SSB index (or an SSB configuration group index) may correspond to an index of a DL bandwidth portion that is correlated with an SSB. An index (or an NCD-SSB configuration group index) of an NCD-SSB (or a UE-specific SSB, a UE-specific NCD-SSB in an SCell) may be correlated with a DL bandwidth portion (or an index of a DL bandwidth portion) corresponding to the NCD-SSB (or a UE-specific SSB, a UE-specific NCD-SSB in an SCell). In an embodiment, an index of an NCD-SSB and an index of a corresponding DL bandwidth portion may be mapped one-to-one. Alternatively, the above-described SSB index may be replaced with an index of a DL bandwidth portion. In other words, a plurality of SSBs (e.g., a plurality of NCD-SSBs, a UE-specific SSB, or a UE-specific NCD-SSB) may be distinguished from each other by indices of DL bandwidth portions corresponding to the plurality of SSBs.

[0135] The above-described SSB indexing (or SSB configuration group indexing) can be applied independently to each terminal. The same index for the same SSB can be assigned to the first terminal and the second terminal. Alternatively, different indices for the same SSB can be assigned to the first terminal and the second terminal. Considering the possibility that different indices for the same SSB are assigned to the first terminal and the second terminal, the base station may need to transmit an SSB adaptation indication signal (e.g., an SSB adaptation indicator, SSB adaptation indication information) to each of a plurality of terminals receiving the SSB in order to control the SSB. When a plurality of terminals are connected to the cell, the signaling overhead for the SSB adaptation indication may increase. Similar to the embodiment of (method 100), it may be difficult to control the SSB reception operation of a terminal in RRC idle / inactive mode with a UE-specific signal (e.g., scheduling DCI, scheduling DCI transmitted in a USS set, DCI format 0_1, DCI format 1_1, etc.).

[0136] As a method for solving the above problem, a method of transmitting SSB adaptation indication information for a plurality of SSBs based on cell-specific signaling or terminal group-specific signaling (e.g., UE group-specific signaling) may be considered. For example, when physical layer signaling is used, the cell-specific signaling may be common DCI (e.g., DCI format 1_0), and the terminal group-specific signaling may be group common DCI (e.g., DCI format 2_X). DCI format 1_0 or DCI format 0_0 may be reused for the purpose of SSB adaptation indication. The DCI may be included in a PDCCH having a CRC scrambled with a specific RNTI, and the PDCCH including the DCI may be transmitted in a specific type of CSS set. For example, the DCI may be transmitted in at least one of type 0 / 0A / 1 / 2 CSS sets used for monitoring operations of legacy terminals. Alternatively, a new CSS set distinct from the above CSS sets may be defined for transmission of the DCI, and the base station may configure the new CSS set to the terminal. The PDCCH including the DCI may have a CRC scrambled by another RNTI distinct from SI-RNTI, RA-RNTI, P(paging)-RNTI, PEI(paging early indicator)-RNTI, etc. For the DCI, a new DCI format distinct from a fallback DCI format may be applied. If there is no separate CORESET setting, the DCI may be transmitted based on CORESET 0. According to another embodiment, DCI format 2_X may be used for the purpose of indicating adaptation of SSBs. X may be an integer greater than or equal to 0.A Type 3 CSS set can be set for terminals camped on a cell or terminals connected to a cell, and the terminals camped on a cell or terminals connected to a cell can monitor a group common DCI including an SSB adaptation indicator in the CSS set. The PDCCH including the group common DCI can have a CRC scrambled by a new RNTI that is distinct from the existing RNTI.

[0137] In the above embodiments, the SSB adaptation indication signal may be a signal commonly received by a plurality of terminals, and the SSB adaptation indication information included in the signal may include UE-specific information. The SSB adaptation indication information may include both common information and UE-specific information. The common information may be CD-SSB (or cell-specific SSB in SCell) adaptation indication information, and the common information may include at least information regarding a transmission period of the CD-SSB (or cell-specific SSB in SCell). The UE-specific information may be NCD-SSB (or UE-specific SSB in SCell) adaptation indication information, and the UE-specific information may include at least information regarding a transmission period(s) of the NCD-SSB (or UE-specific SSB in SCell).

[0138] Figure 9 is a conceptual diagram illustrating an embodiment of a method for setting SSB adaptation instruction information.

[0139] Referring to FIG. 9, SSB adaptation indication information transmitted via DCI may include a plurality of information blocks. Each information block may include control information to be transmitted to a terminal and may include one or more DCI field(s). The plurality of information blocks may include common block(s) (e.g., cell-specific block(s), cell-specific information block(s)) including common SSB adaptation indication information and / or UE-specific block(s) (e.g., UE-specific information block(s)) including UE-specific SSB adaptation indication information. For example, a first information block may be a common block and may include information regarding a transmission period of a CD-SSB. A terminal performing a reception operation of a CD-SSB (or a cell-specific SSB in an SCell) may receive the DCI and commonly obtain the first information block based on the received DCI. The second information block and the information blocks after the second information block may be UE-specific blocks and may include information regarding a transmission period of the NCD-SSB (or UE-specific SSB in SCell). Alternatively, the DCI may not include CD-SSB (or cell-specific SSB in SCell) control information and may include only UE-specific block(s). Each information block may include at least information regarding a transmission period of the NCD-SSB (or UE-specific SSB in SCell). A terminal receiving the NCD-SSB (or UE-specific SSB in SCell) may acquire one or more UE-specific block(s) based on the DCI. To support the above-described operation, the base station may set (e.g., instruct) the terminal the start position of the information block received by the terminal (e.g., the first bit to which the information block is mapped). In acquiring the UE-specific block, the same information block may be received by multiple terminals.In other words, multiple terminals can obtain UE-specific blocks with the same information.

[0140] A UE-specific block (e.g., a UE-specific information block) may include period values ​​(e.g., transmission period values) for one or more NCD-SSB(s) (or UE-specific SSB(s) in an SCell) depending on the UE. The UE-specific block (e.g., a UE-specific information block) may further include information about an SSB to which each SSB transmission period is to be applied (e.g., an SSB index, a bandwidth fraction index correlated with the SSB). The size of the UE-specific block may be determined by the number of SSB periods included in the information block. The size (e.g., number of bits) of the UE-specific block to be received by the UE may be explicitly set (e.g., indicated) to the UE. Alternatively, the UE may implicitly determine the size (e.g., number of bits) of the UE-specific block to be received by the UE based on the size (e.g., number of SSB periods) of the SSB adaptation indication information included in the UE-specific block without separate signaling. One UE-specific block may contain SSB control information for one serving cell.

[0141] In another embodiment, blocks (e.g., information blocks) included in the DCI may not be distinguished into common blocks and UE-specific blocks. Each block may include information common to a plurality of terminals (e.g., periodic value(s) of CD-SSB or periodic value(s) of cell-specific SSB). Alternatively, each block may include UE-specific information (e.g., periodic value(s) of NCD-SSB or periodic value(s) of UE-specific SSB). Blocks including information common to a plurality of terminals (e.g., periodic value(s) of CD-SSB or periodic value(s) of cell-specific SSB) may be configured to be received by a plurality of terminals based on RRC settings transmitted to each of the plurality of terminals.

[0142] Meanwhile, a terminal for which carrier aggregation is configured may receive a plurality of information blocks for adaptation of SSBs transmitted from a plurality of serving cells. The plurality of information blocks for the plurality of serving cells may be included in one DCI or one MAC CE. In the above embodiments, the plurality of SSBs may be SSBs configured for different serving cells. For example, the terminal may check the period value of a CD-SSB (or NCD-SSB) configured for a first serving cell and the period value of a CD-SSB (or NCD-SSB) configured for a second serving cell through one DCI. The time points at which the plurality of SSB adaptation instructions are applied to each serving cell corresponding to the plurality of SSB adaptation instructions may be the same. For example, the common time point at which the plurality of SSBs are applied may be a specific slot considering the reception time point of the DCI, the subcarrier spacing of the serving cell in which the DCI is received, etc. Alternatively, the timing at which the plurality of SSB adaptation instructions are applied to each serving cell corresponding to the plurality of SSB adaptation instructions may or may not coincide, depending on the case. For example, each SSB adaptation instruction may be applied from a specific slot of the serving cell to which the SSB belongs, and the starting slot (e.g., the specific slot to which the SSB adaptation instruction is applied) may be determined as different timings in consideration of the reception timing of the DCI, the subcarrier spacing of the serving cell to which each SSB belongs, the period of each SSB, the period value of each SSB, etc. According to the above-described method, transmission parameters (e.g., period values) of SSBs set in a plurality of serving cells (or a plurality of carriers) by one DCI may be simultaneously controlled, and control signaling overhead may be reduced.

[0143] A terminal in RRC idle / inactive mode can receive a first information block (e.g., a common block) among a plurality of information blocks, and the CD-SSB can be controlled based on the first information block. Alternatively, a terminal in RRC idle / inactive mode can receive not only the common block but also a UE-specific block, and the CD-SSB and the NCD-SSB can be controlled together based on the common block and the UE-specific block. Configuration information (e.g., start position, size, information configuration) regarding the UE-specific block can be transmitted to the terminal via system information (e.g., SIB1, SIBx). Alternatively, when the terminal operates in RRC connected mode, configuration information (e.g., start position, size, information configuration) regarding the UE-specific block can be transmitted to the terminal by UE-specific RRC signaling (e.g., an RRC configuration message, an RRC release message, etc.).

[0144] According to the above method, the SSB transmission periods of multiple terminals can be controlled cell-specifically and UE-specifically with a single signaling, and simultaneously, multiple SSB transmission periods can be individually controlled. Therefore, signaling overhead can be maintained at a low level while ensuring SSB control freedom.

[0145] Meanwhile, a cell can transmit multiple SSBs based on the same periodic value. For example, multiple SSBs can be multiplexed in the frequency domain within the same time resource, and the multiple SSBs can be transmitted with the same periodic value. To control the operation of multiple SSBs, the base station can transmit a single common periodic value to the terminal via DCI. Based on the above-described operation, the SSB transmission interval can be minimized, and the base station's sleep time can be further secured.

[0146] Fig. 10 is a conceptual diagram illustrating an embodiment of a method for setting SSB adaptation instruction information.

[0147] Referring to FIG. 10, SSB adaptation indication information may include an SSB period value and one or more information block(s). The SSB period value may be a period value commonly applied to a plurality of SSBs, and the plurality of SSBs may include a CD-SSB and a NCD-SSB. Alternatively, the plurality of SSBs may include a cell-specific SSB and a UE-specific SSB. The SSB period value may be included in a separate information block, and the separate information block may be mapped to a payload. Each information block may include information indicating a set of SSB(s) controlled specifically by the UE. For example, each information block may include SSBs configured for the UE (or indices corresponding to the SSBs). The UE may receive the information block configured for the UE, apply the SSB period value to the SSBs (e.g., NCD-SSBs) and / or CD-SSBs indicated by a field in the information block, and receive the SSBs based on the SSB period value. The SSB period value can be mapped to the most significant bit (e.g., the MSB(s)) of the SSB adaptation instruction information. Alternatively, the SSB period value can be mapped to the position preceding each information block.

[0148] Alternatively, one information block included in the DCI (e.g., a cell-specific block or a UE-specific block as described in the embodiment of FIG. 9) may include a common SSB periodicity value and information about the SSB(s) to which the common SSB periodicity value applies (e.g., SSB index(es), index(es) of bandwidth portions interrelated with the SSBs).

[0149] In a modified embodiment, NCD-SSBs can be transmitted based on a common period value, and it can be allowed for CD-SSBs to be transmitted with a different period from NCD-SSBs. To support the above-described operation, a method in which SSB adaptation indication information includes two SSB period values ​​can be considered. The two SSB period values ​​can include a period value of the CD-SSB and a period value commonly applied to the NCD-SSBs. The terminal can receive an information block set to itself, apply the NCD-SSB period value to SSBs (e.g., NCD-SSBs) indicated by a field in the information block, and receive the SSBs based on the applied period value.

[0150] In another embodiment, the SSB adaptation indication signal may be a common signal, and the SSB adaptation indication information included in the SSB adaptation indication signal may be information common to the terminals.

[0151] Fig. 11 is a conceptual diagram illustrating an embodiment of a method for setting SSB adaptation instruction information, and Fig. 12 is a conceptual diagram illustrating an embodiment of a method for setting SSB adaptation instruction information.

[0152] Referring to FIGS. 11 and 12, SSB adaptation indication information transmitted via DCI may include common information. According to the embodiment of FIG. 11, the common information may include N SSB periodicity value(s). N may be a natural number. The N SSB periodicity values ​​may correspond to N SSBs based on a predefined rule. For example, a first SSB periodicity value may correspond to a CD-SSB, and the remaining (N-1) SSB periodicity values ​​may correspond to NCD-SSBs sequentially (e.g., in ascending order of index). As another example, the N SSB periodicity values ​​may correspond to N SSBs sequentially (e.g., in ascending order of index). Alternatively, the N SSBs may be explicitly set to the terminal via RRC signaling. According to the embodiment of FIG. 12, the common information may include (index, periodicity value) pairs for N SSBs to be controlled. In the above embodiments, the N SSBs may or may not include a CD-SSB. Considering a terminal in RRC idle / inactive mode, the RRC signaling may be defined as SIB1 or SIBx. Each terminal may receive some or all of the common information based on the configuration from the base station.

[0153] A condition for the above embodiments to operate may be that the same SSB index for the same SSB is assigned to multiple terminals. The SSB index may be assigned cell-specifically. The NCD-SSB may be configured identically for multiple terminals in a cell-specific manner, and the cell-specific SSB index assigned to each NCD-SSB may be correlated with each DL bandwidth portion configured for each terminal. For example, the configuration information of the NCD-SSB may be defined as a sub-parameter of the RRC parameter servingCellConfigCommon. Alternatively, the NCD-SSB configuration information may be defined as a UE-specific message, and the base station may implementally configure the NCD-SSB configuration information including the NCD-SSB index identically for multiple terminals.

[0154] Meanwhile, a method of controlling one SSB with one DCI in (method 200) may be used. (Method 200) may differ from the embodiment of (method 100) in that the same signaling procedure is used to control CD-SSB and NCD-SSB, and the specific operation of (method 200) may be the same as or similar to the embodiment of (method 100).

[0155] As in the above-described embodiment, the SSB adaptation indication information (e.g., SSB period value) indicated by the DCI or MAC CE can be applied for a predetermined duration (e.g., time duration). The duration can include N SSB periods. N can be a natural number. The length of the duration (e.g., the value of N) can be predefined in the technical specification. Alternatively, the base station can inform the terminal of the length of the duration (e.g., the value of N) through signaling. Alternatively, the duration can be determined by a timer operation. The duration can be defined as a time interval from the time when the timer starts to the time when it expires. The N SSB period(s) can be period(s) based on the SSB period value indicated by the DCI or MAC CE. Alternatively, the N SSB period(s) may be period(s) formed by the SSB period value indicated by the DCI or MAC CE and any one of the SSB period values ​​(e.g., a large period value or a small period value) of the previous SSB period value. The start time (e.g., a start slot, a start half radio frame, a start radio frame) of the duration may be determined as any one time point after the time point (hereinafter referred to as the "first time point") at which the terminal receives the DCI or MAC CE indicating SSB adaptation indication information or after a time point (hereinafter referred to as the "second time point") that is a predetermined time offset from the first time point. The time offset may include at least a processing time required for the terminal to receive the DCI or MAC CE and obtain the SSB adaptation indication information. If a bandwidth portion (e.g., a DL bandwidth portion) switching occurs during the duration, the terminal may perform an SSB reception operation based on the SSB adaptation indication in the bandwidth portion before the bandwidth portion is switched.Alternatively, the terminal may perform an SSB reception operation according to the SSB adaptation instruction in the bandwidth portion after the bandwidth portion has been switched. The operation may be performed when the SSB that is the target of the SSB adaptation instruction belongs to the bandwidth portion after the bandwidth portion has been switched, or when the SSB that is the target of the SSB adaptation instruction is interrelated with the bandwidth portion after the bandwidth portion has been switched.

[0156] The terminal can confirm the indication of the first SSB period value through the first DCI (or, the first MAC CE) and apply the indicated first SSB period value during the first duration. The terminal can receive another DCI (e.g., the second DCI) or a second MAC CE indicating the second SSB period value during the first duration (e.g., before the operation indicated through the first DCI is completed). The second SSB period value can be applied during the second duration, and the second SSB period value can be the same as or different from the first SSB period value.

[0157] The terminal may apply the instruction by the second DCI. For example, the terminal may receive SSB based on the SSB adaptation instruction indicated by the DCI (or MAC CE), regardless of whether the reception time of the second DCI is included in the first duration, whether the second duration overlaps with the first duration, etc. In other words, the terminal may apply the SSB adaptation instruction to both the first duration and the second duration. If the first duration and the second duration overlap, the SSB adaptation instruction may be applied to the union of the first duration and the second duration. For another example, the above operation may be performed conditionally. If the second SSB period value is equal to the first SSB period value, the terminal may operate based on the instruction by the second DCI. If the second duration does not overlap with the first duration, the terminal may operate based on the instruction by the second DCI. If the instruction by the second DCI has a higher priority than the instruction by the first DCI, the terminal may operate based on the instruction by the second DCI. If the first and second durations overlap, the terminal may operate based on the most recently received SSB adaptation instruction.

[0158] Alternatively, the terminal may ignore the indication by the second DCI. For example, if the reception time of the second DCI falls within the first duration and / or the second duration overlaps with the first duration, the terminal may receive SSB without applying the SSB adaptation indication by the second DCI. This operation may be performed if the second SSB period value is different from the first SSB period value.

[0159] The above-described SSB adaptation indication information can be signaled to the UE together with adaptation indication information of other physical signals / channels. The SSB adaptation indication information can be included in the DCI together with the PRACH adaptation indication information. Alternatively, the SSB adaptation indication information can be included in the DCI together with the paging adaptation indication information. Each of the PRACH resources and the paging resources can include cell-specific resources and UE-specific resources. The paging resources can include paging frames and / or paging occasions in which the UE performs a PDCCH monitoring operation for paging reception. The method of setting the SSB adaptation indication information by dividing it into common information and UE-specific information can be applied identically or similarly to setting the PRACH adaptation indicator and the paging adaptation indicator. For example, similar to the embodiment of FIG. 9, the DCI can include common PRACH adaptation indication information and UE-specific PRACH adaptation indication information, and the common PRACH adaptation indication information can be applied to cell-specific PRACH resources, and the UE-specific PRACH adaptation indication information can be applied to UE-specific PRACH resources. Alternatively, a plurality of cell-specific PRACH resources and / or a plurality of cell-specific paging resources may be configured in the terminal, and adaptation indication information regarding the plurality of cell-specific PRACH resources and / or the plurality of cell-specific paging resources may be signaled to the terminal based on the above-described method together with the SSB adaptation indication information.

[0160] Multiple PRACH resources can be distinguished by PRACH resource indices or PRACH configuration indices. The PRACH adaptation indication information can include the PRACH resource index or PRACH configuration index to which the corresponding PRACH adaptation indication is to be applied. Multiple paging resources can be distinguished by paging resource indices or paging configuration indices. The paging adaptation indication information can include the paging resource index or paging configuration index to which the corresponding paging adaptation indication is to be applied.

[0161] SSB adaptation indication information may or may not be included in the DCI. Information indicating whether the DCI includes SSB adaptation indication information may be included in the DCI. The information may be information explicitly indicating whether an SSB adaptation indicator is included. Alternatively, the information may be information indicating the type of adaptation indication information included in the DCI. For example, the types of adaptation indicators included in the DCI, such as an SSB adaptation indicator, a PRACH adaptation indicator, and / or a paging adaptation indicator, may be indicated by a specific field of the DCI. If the specific field does not indicate an SSB adaptation indicator, the UE may consider that the DCI does not include SSB adaptation indication information. In the above embodiment, the operations applied to the DCI may be identically or similarly applied to the MAC CE.

[0162] The above embodiments can be applied when the serving cell is a PCell. When the serving cell is a SCell (secondary cell), the SSB adaptation indication method can be similar to that when the serving cell is a PCell, and as in the above-described embodiment, the UE may not distinguish between CD-SSB and NCD-SSB. Therefore, when the serving cell is an SCell, the SSB adaptation indication can be set in a form that does not distinguish between CD-SSB and NCD-SSB. For example, in the above embodiments, the remaining portions other than the adaptation indication portion for CD-SSB can be used for SSB adaptation indication of the SCell. Alternatively, as in the above-described embodiment, the CD-SSB and NCD-SSB can correspond to cell-specific SSB and UE-specific SSB configured in the SCell, respectively. Alternatively, the CD-SSB and NCD-SSB can be distinguished in the SCell. Based on the above embodiments, the SSB(s) configured in the SCell can be controlled.

[0163] The terminal may monitor DCI for SSB adaptation indication in the first search space set. In the above-described operation, the first search space set may be a CSS set or a USS set. To support the above-described operation, configuration information of the first search space set and / or configuration information of a CORESET that is mutually associated with the first search space set may be signaled to the terminal. If an SSB adaptation indicator is included in the DCI, the time point at which the SSB adaptation indicator is applied may be determined as a time point (hereinafter referred to as a "second time point") that has elapsed by a preset time from the time point at which the terminal receives the DCI (hereinafter referred to as a "first time point"). If the SSB adaptation indicator is included in a MAC CE and the MAC CE is transmitted via a PDSCH, a reference time point (e.g., the first time point) for determining the time point at which the SSB adaptation indicator is applied may be a time point at which the terminal receives the PDSCH or a time point at which the terminal receives a DCI that schedules the PDSCH. For example, the terminal may apply the SSB adaptation indicator starting from the first slot that appears K1 symbols after the last symbol of the DCI (or the PDSCH). As another example, the terminal may apply the SSB adaptation indicator starting from the slot that is K2 slot(s) later than the slot in which the DCI (or the PDSCH) is received. Each of K1 and K2 may be a natural number. The base station may indicate the value of K1 and / or the value of K2 to the terminal through signaling. The terminal may check the value of K1 and / or the value of K2 through signaling from the base station. Alternatively, the value of K1 and / or the value of K2 may be defined in a technical specification.

[0164] The change of the SSB cycle value can be performed in units of SSB cycles. When the terminal receives a DCI for an SSB adaptation instruction, the terminal can apply the cycle value according to the SSB adaptation instruction from the first SSB cycle (e.g., the start time of the first SSB cycle) that appears after the DCI reception time (or, a time point that has passed by a preset time offset from the DCI reception time). The SSB cycle may be a cycle formed based on the indicated SSB cycle value. Alternatively, the SSB cycle may be a cycle formed based on a previous SSB cycle value. Alternatively, the SSB cycle may be a cycle formed based on either the previous SSB cycle value or the indicated SSB cycle value (e.g., a small cycle value or a large cycle value).

[0165] A first search space set may be set in the cell DTX active duration and non-active duration, and the terminal may monitor DCI for SSB adaptation instruction in the cell DTX active duration and non-active duration. The first search space set may be monitored in the active time and non-active time of C(cell)-DRX. Alternatively, the terminal may monitor DCI format 2_9 in the first search space set, and the first search space set may be monitored in the cell DTX active duration. The terminal may not perform a monitoring operation of the DCI in the first search space set set in the cell DTX non-active duration. The terminal may not expect that the first search space set is set in the cell DTX non-active duration. In addition to the DCI monitoring operation, an operation of receiving an SSB may be performed regardless of a cell DTX operation and / or a C-DRX operation set in the terminal. Specifically, the SSB adaptation instruction can be applied to both the active time and the inactive time of the cell DTX and / or C-DRX, and the terminal can receive SSB based on the SSB adaptation instruction in the active time and the inactive time. The duration to which the SSB adaptation instruction is applied can include at least one of the active time or the inactive time.

[0166] Cross-carrier SSB adaptation indication may be supported. A terminal may receive an SSB adaptation indication from a first carrier and apply the SSB adaptation indication to an SSB reception operation and an SSB-related operation of a second carrier. The first carrier may be different from the second carrier. When the numerology (e.g., subcarrier spacing) of the first carrier and the second carrier are the same, the application time of the SSB adaptation indication may be determined based on the method described above. When the numerology (e.g., subcarrier spacing) of the first carrier and the second carrier are different, the application time of the SSB adaptation indication may be determined based on the numerology (e.g., subcarrier spacing) of the first carrier. For a terminal performing a dual connectivity operation, the first carrier and the second carrier may be carriers or serving cells belonging to the same cell group.

[0167] The second carrier may be an SCell, and the first carrier may be a PCell or a different SCell from the SCell. If the second carrier is a PCell, the first carrier may be a PCell. In other words, the adaptation indication information of the SSB set in the PCell may be restricted to be transmitted from the PCell. Considering cases where control signaling is offloaded to the SCell and / or cases where the link quality of the SCell is better than that of the PCell, a method of transmitting the adaptation indication information of the SSB set in the PCell from the SCell may be considered. By the above method, the period of one or more SSB(s) set in the second carrier may be controlled. The SSB(s) that are targets of the SSB adaptation indication may be SSBs that are correlated with a DL bandwidth portion activated in the second carrier. Some DL bandwidth portions set in the second carrier may be dormant bandwidth portions, and other DL bandwidth portions may be non-dormant bandwidth portions. If the dormant bandwidth portion includes a CD-SSB (e.g., cell-specific SSB), the CD-SSB (e.g., cell-specific SSB) may be adapted for the dormant bandwidth portion. If the dormant bandwidth portion does not include a CD-SSB, the terminal may receive a NCD-SSB (e.g., UE-specific SSB) configuration for the dormant bandwidth portion for the purpose of managing synchronization, CSI, beams, etc. in the section where the dormant bandwidth portion is activated, and the terminal may perform the above operation based on the NCD-SSB (e.g., UE-specific SSB) configuration.

[0168] The monitoring period of the first search space set can have an independent value regardless of the SSB transmission period. The monitoring period of the first search space set can be set to an independent value regardless of the PRACH resource period, the paging resource period, etc. In this case, the application point of the SSB adaptation instruction can be located in the middle of the SSB burst period. The SSB burst period can mean a set of slots to which the SSBs constituting the SSB burst are mapped. Alternatively, the SSB burst period can mean a period from the first symbol of the first SSB constituting the SSB burst to the last symbol of the last SSB.

[0169] Figure 13 is a conceptual diagram illustrating an embodiment of an SSB transmission method that takes into account the application timing of an SSB adaptation instruction.

[0170] Referring to FIG. 13, a terminal may receive an SSB adaptation indicator from a base station, and based on the SSB adaptation indicator, the terminal may change an SSB reception period (e.g., an SSB transmission period assumed by the terminal) from a first period value to a second period value. The second period value (e.g., 40 ms) may be greater than the first period value (e.g., 20 ms). The SSB adaptation indicator may be transmitted via DCI or PDSCH. The application time of the SSB adaptation indicator may be located in the middle of an SSB burst. In the embodiment of FIG. 13, the application time of the SSB adaptation indicator may be determined as a time between the second SSB and the third SSB constituting the SSB burst. For example, the second SSB and the third SSB may be mapped to different slots, and the SSB adaptation indicator may be determined to be applied starting from the slot to which the third SSB is mapped. If the application time of the SSB adaptation indicator is determined to be before the SSB burst interval, the SSB burst may be considered not to be transmitted due to the extended period value. If the application time of the SSB adaptation indicator overlaps with the SSB burst interval, several embodiments may be considered as terminal assumptions for the SSB burst transmission.

[0171] In one embodiment, the terminal can receive the entire SSB burst. In other words, the terminal can assume that all of the first to sixth SSBs constituting the SSB burst, including the third to sixth SSBs mapped after the time point of applying the SSB adaptation indication, are transmitted. In another embodiment, the terminal can receive only a portion of the SSB burst. For example, the terminal can assume that the first and second SSBs mapped before the time point of applying the SSB adaptation indication are transmitted, and the third to sixth SSBs mapped after the time point of applying the SSB adaptation indication are not transmitted. In another embodiment, the terminal may not expect the above-described case (e.g., when the time point of applying the SSB adaptation indication overlaps with the SSB burst period). The base station can appropriately set the SSB period, the offset of the half radio frame, the period of the first search space set, and / or the monitoring occasion so that the application time of the SSB adaptation instruction does not overlap with the SSB burst period.

[0172] In another embodiment, when a terminal receives an SSB adaptation instruction, the terminal may not apply the SSB adaptation instruction during the SSB period to which the first time point or the second time point belongs, and may perform an SSB reception operation or a monitoring operation based on a previous SSB period value (e.g., an SSB period value previously indicated to the terminal) during the SSB period. The terminal may receive an SSB based on the indicated SSB period value (e.g., an SSB period value based on the SSB adaptation instruction) from the earliest SSB period that appears after the first time point or the second time point. The earliest SSB period may be the earliest SSB period that appears based on the indicated SSB period value. Alternatively, the earliest SSB period may be the earliest SSB period that appears based on one of the previous SSB period value and the indicated SSB period value (e.g., a larger period value). In the embodiment, the SSB adaptation instruction may be performed in units of SSB periods.

[0173] In another embodiment to avoid the application time of the SSB adaptation instruction from overlapping with the SSB burst period, the monitoring period of the first search space set may be associated with at least one of an SSB transmission period, a PRACH resource period, or a paging resource period. For example, the period of the first search space set may be set to a divisor or multiple of the SSB transmission period. Specifically, the period of the first search space set may be restricted to have a value that is a divisor or multiple of a specific SSB period value (e.g., a default SSB period value, a largest SSB period value, a smallest SSB period value) among candidate SSB period values ​​set in the terminal. The position of the slot(s) to which the first search space set (or the PDCCH monitoring occasion corresponding to the first search space set) is mapped may be expressed as a relative distance (e.g., a time offset) with respect to the position of the SSB burst resource, and the time offset may be signaled to the terminal. For example, the first slot to which the first search space set is mapped can be indicated to the terminal as a slot offset from the first slot to which the SSB burst is mapped. The slot offset can be a natural number or a negative integer. The absolute value of the slot offset can be greater than or equal to a predefined reference value in the technical specification. The reference value can be determined by considering the time delay until the time point of application of the SSB adaptation instruction. For example, the reference value can be defined as a value equal to or greater than the time delay until the time point of application of the SSB adaptation instruction.

[0174] In the above-described method, the SSB can be activated or deactivated. The CD-SSB and / or NCD-SSB (or cell-specific SSB and / or UE-specific SSB) configured in the UE can be activated, deactivated, or updated by a dynamic signaling procedure or a semi-static signaling procedure. The dynamic signaling procedure may include a MAC CE, and the semi-static signaling procedure may include an RRC signaling procedure. The MAC CE may include information indicating SCell activation together with SSB activation / deactivation indication information. Alternatively, the dynamic signaling procedure may include a DCI. For example, the DCI may include a field indicating SSB activation or SSB deactivation, and the size of the field may be 1 bit. If the target of the SSB activation or SSB deactivation indication is a plurality of SSBs, the size of the field may be larger than 1 bit. The SSB may be referred to as an on-demand SSB or a semi-persistent SSB. SSB configuration information may include information regarding whether SSB is on-demand SSB (e.g., information indicating whether SSB can be enabled / disabled). SSB enablement may mean that the terminal can receive SSB in the SSB-enabled section. SSB disablement may mean that the terminal does not receive SSB in the SSB-disabled section.

[0175] The SSB adaptation indication can be applied to an activated SSB. For example, the terminal can receive a MAC CE, obtain information indicating to activate a first SSB based on the MAC CE, and activate the first SSB based on the indication. The period value of the first SSB can be indicated by the MAC CE. Alternatively, the period value of the first SSB can be preset by RRC signaling. In the section in which the first SSB is activated, the terminal can receive a DCI or another MAC CE, and obtain information indicating to change the period value of the first SSB to another period value based on the DCI or the other MAC CE. The terminal may not expect to receive SSB adaptation indication information for a deactivated SSB. Alternatively, the terminal may ignore the SSB adaptation indication information when the SSB is dynamically activated / deactivated. According to the above-described method, it may be difficult to determine whether the SSB adaptation indication is applied when the SSB is dynamically activated / deactivated.

[0176] A method of indicating SSB transmission parameters to a terminal regardless of the SSB's activation / deactivation status may be considered. The terminal may apply an SSB adaptation instruction to the SSB regardless of the SSB's activation / deactivation status. For example, an SSB received based on a first period value may be deactivated, and the terminal may receive information instructing to change the period value of the SSB from the first period value to a second period value in a section where the SSB is deactivated. In this case, the terminal may change the period value of the SSB to the second period value based on the instruction, and may receive the SSB based on the second period value when the SSB is activated. The point in time when the SSB's period value is changed to the second period value may be determined based on the point in time when the SSB adaptation instruction information is received or the point in time when the SSB is activated. For example, the terminal may maintain the period value at the first period value in a section where the SSB is deactivated, and may change the period value to the second period value from the point in time when the SSB is activated. In other words, the terminal can apply the second period value from the time the SSB is activated.

[0177] The SSB adaptation indication information may be included in a signaling message (e.g., MAC CE, RRC message) indicating that SSB is to be activated. The SSB adaptation indication information included in the signaling message may be applied from the time that SSB is activated. The SSB adaptation indication information may be included in a signaling message (e.g., MAC CE, RRC message) indicating that SSB is to be deactivated. The SSB adaptation indication information included in the signaling message may be applied from the time that SSB is deactivated. Alternatively, the SSB adaptation indication information included in the signaling message may be applied when the SSB is next activated.

[0178] For the same SSB, a first SSB adaptation indication included in an SSB activation indication message (e.g., MAC CE or RRC) and a second SSB adaptation indication by DCI may conflict. For example, the application time of the first SSB adaptation indication may coincide with the application time of the second SSB adaptation indication. In other words, the application time of the first SSB adaptation indication and the application time of the second SSB adaptation indication may belong to the same slot. Alternatively, the time interval between the application time of the first SSB adaptation indication and the application time of the second SSB adaptation indication may be within a reference value. The priority rule between the first SSB adaptation indication and the second SSB adaptation indication may be defined in the technical specification. Alternatively, the priority rule between the first SSB adaptation indication and the second SSB adaptation indication may be set (e.g., instructed) from the base station to the terminal. The terminal may operate based on either SSB adaptation indication based on the priority rule. For example, the second SSB adaptation indication may have priority over the first SSB adaptation indication. Alternatively, the priority rule may be conditionally applied only when a predefined condition is satisfied. In another embodiment, the terminal may expect that the first SSB adaptation instruction and the second SSB adaptation instruction contain the same SSB indication information. For example, the terminal may expect that the SSB period value indicated by the first SSB adaptation instruction and the SSB period value indicated by the second SSB adaptation instruction are identical.

[0179] Meanwhile, an on-demand SSB may be transmitted during a specific time interval and may not be transmitted after the specific time interval. In this case, it may be unnecessary to dynamically indicate the period value of the SSB based on the DCI. In another proposed method, the above-described SSB dynamic adaptation indication method can be applied to an SSB other than an on-demand SSB (or a semi-permanent SSB). In the above embodiments, an SSB may mean an SSB that is transmitted periodically, and the SSB may mean an SSB that is not an on-demand SSB. The base station may set (e.g., instruct) the terminal through signaling information indicating whether to assume either an on-demand operation or a periodic operation for the same SSB. The terminal may assume either an on-demand operation or a periodic operation for the same SSB based on the signaling of the base station. For example, the SSB configuration information may include an SSB type (or a parameter corresponding to the SSB type), and the candidates (e.g., candidate values) of the SSB type may include at least an on-demand type and a periodic type. In this case, according to the above-described method, the SSB dynamic adaptation indication method may not be applied in a section where the SSB is transmitted and received based on the on-demand type, and the SSB dynamic adaptation indication method may be applied in a section where the SSB is transmitted and received based on the periodic type.

[0180] Alternatively, the SSB dynamic adaptation indication method may be applied in a section where the SSB is activated, and the SSB dynamic adaptation indication method may not be applied in a section where the SSB is deactivated. The terminal may ignore the adaptation indication information when the adaptation indication information is received for the deactivated SSB. In the above-described embodiment, the terminal may receive the adaptation indication information in a section where the SSB is deactivated, and apply the adaptation indication information when the SSB is activated. For example, the terminal may receive information indicating that the period value of the SSB is to be set to a first period value in a section where the SSB is deactivated. The terminal may apply the first period value in a section where the SSB is activated, and receive the SSB based on the first period value.

[0181] Alternatively, an on-demand SSB may be correlated with at least one other SSB (e.g., a periodic SSB). The correlation may be established directly between the SSBs. Alternatively, the correlation may be established indirectly based on a DL bandwidth portion, a serving cell, etc., that is correlated with the SSBs. For example, an on-demand SSB may be transmitted on the same DL bandwidth portion as a periodic SSB, and the on-demand SSB may be correlated with the periodic SSB. In the above-described situation, when a terminal receives a dynamic adaptation instruction for some of the correlated SSBs, the terminal may equally apply the dynamic adaptation instruction not only to the some of the correlated SSBs but also to other SSBs correlated with the some of the SSBs. In an embodiment, the terminal may receive a dynamic adaptation instruction for a periodic SSB, and apply the dynamic adaptation instruction to the periodic SSB and an on-demand SSB correlated with the periodic SSB.

[0182] When an SSB (e.g., an on-demand SSB) that a terminal is receiving is deactivated, the terminal may stop an operation based on the SSB (e.g., an RRM operation, an RLM operation, a CSI measurement operation, a CSI reporting operation, a beam measurement operation, a beam reporting operation). Alternatively, the terminal may receive another SSB to replace the SSB (e.g., the deactivated SSB). The other SSB may be conveniently referred to as a fallback SSB. The fallback SSB may be a periodic SSB correlated with the on-demand SSB. Alternatively, the fallback SSB may be a periodic SSB transmitted in the same bandwidth portion as the on-demand SSB. Alternatively, the fallback SSB may refer to an SSB correlated with a specific bandwidth portion (e.g., a DL bandwidth portion), an SSB transmitted on another serving cell (e.g., a PCell), or an SSB transmitted on another carrier. Simultaneously with or separately from the above-described embodiments, the fallback SSB may be a cell-specific SSB (e.g., CD-SSB). In an SCell, if a cell-specific SSB (e.g., CD-SSB) is configured, the fallback SSB may be the cell-specific SSB (e.g., CD-SSB), and if the cell-specific SSB (e.g., CD-SSB) is not configured, the fallback SSB may be determined by the above-described method. The bandwidth portion or the serving cell for receiving the fallback SSB may be predefined in the technical specification. Alternatively, the bandwidth portion or the serving cell for receiving the fallback SSB may be configured from the base station to the terminal. Alternatively, the base station may directly configure the fallback SSB to the terminal. The terminal may perform SSB-related operations based on the fallback SSB. The fallback SSB may have a QCL relationship with an on-demand SSB (e.g., the deactivated SSB).For example, the fallback SSB and the on-demand SSB (e.g., the deactivated SSB) may each include M SSBs (e.g., SSBs that are actually transmitted), and the M fallback SSBs and the M on-demand SSBs may have a QCL relationship with each other. In other words, each fallback SSB and each on-demand SSB may have a QCL relationship with each other. M may be a natural number. In the present disclosure, the deactivated SSB may mean an SSB that is not transmitted by the base station or an SSB that is not received by the terminal.

[0183] A terminal can measure CSI based on on-demand SSB and report the measured CSI to a base station. The CSI can include at least one of a channel quality indicator (CQI), a precoding matrix indicator (PMI), a rank indicator (RI), a CSI-RS resource indicator (CRI), or a layer indicator (LI). The terminal can measure beam quality (e.g., L1-RSRP, L1-SINR, etc.) based on on-demand SSB and report the measured beam quality to a base station. Beam quality information can be included in the CSI report and transmitted to the base station. The CSI report can be transmitted via PUCCH or PUSCH. CSI report based on on-demand SSB can be transmitted semi-persistently or aperiodicly, and periodic CSI report may not be supported. Semi-persistent CSI report can be triggered or activated / deactivated by MAC CE and / or DCI. Aperiodic CSI report can be triggered by DCI. The above DCI may be transmitted via a PDCCH having a CRC scrambled by an RNTI (e.g., SSB-RNTI, SP-SSB-RNTI, etc.) that is distinct from the C-RNTI.

[0184] The above CSI reporting operation can be performed for activated on-demand SSB. If on-demand SSB is deactivated, the on-demand SSB can be excluded from CSI resources for CSI measurement and reporting. If "a bandwidth portion (e.g., a DL bandwidth portion or an UL bandwidth portion) corresponding to CSI reporting based on on-demand SSB is deactivated" or "a serving cell corresponding to CSI reporting based on on-demand SSB is deactivated", the CSI reporting can also be deactivated. Information indicating to activate the CSI reporting can be signaled to the terminal so that the terminal can resume the CSI reporting operation in the activated bandwidth portion (e.g., another activated bandwidth portion) or the activated serving cell (e.g., another activated serving cell).

[0185] As described above, the terminal can receive configurations for both periodic SSB and on-demand SSB for one serving cell. In an embodiment, the one serving cell may be a SCell. The periodic SSB may be a cell-specific SSB included in the cell common information of the SCell (e.g., a CD-SSB defining the SCell). The on-demand SSB may be transmitted at the same frequency location as the periodic SSB. The on-demand SSB may not be correlated with SIB1. In other words, the PBCH (or MIB) constituting the on-demand SSB may not include information indicating a CORESET and a type 0-PDCCH CSS set for SIB1 PDCCH monitoring of the terminal. However, the on-demand SSB may be an SSB that complements the transmission density of the periodic SSB, which is a CD-SSB, and the on-demand SSB may be considered a CD-SSB. In other words, the CD-SSB may be transmitted based on two period values. The CD-SSB may be transmitted periodically based on a first period value, and the CD-SSB may be transmitted temporarily based on a second period value. The CD-SSB transmitted based on the second period value may not be associated with SIB1. In other words, the payload (e.g., a specific field) of the MIB of the CD-SSB transmitted based on the second period value may have a different value from the payload (e.g., a specific field) of the MIB of the CD-SSB transmitted based on the first period value. Alternatively, the MIB of the CD-SSB transmitted based on the second period value may be configured with the same payload as the MIB of the CD-SSB transmitted based on the first period value, and the terminal may ignore at least some information included in the MIB of the CD-SSB transmitted based on the second period value.For example, the terminal may ignore k_SSB, CORESET 0 configuration information, pdcch-SIB1 configuration information, etc. included in the MIB of CD-SSB transmitted based on the second period value, and may not perform the corresponding PDCCH monitoring operation in the section corresponding to the information (e.g., ignored information).

[0186] The terminal may assume that the SSB is transmitted based on the second period value in the first interval and the SSB is transmitted based on the first period value in the second interval. The terminal may perform a reception operation of the CD-SSB based on the assumption. The second interval may be a time interval that appears after the first interval. In the first interval, the SIB1 associated with the SSB may not be transmitted, and in the second interval, the SIB1 associated with the SSB may be transmitted. In other words, the SSB may be switched from a NCD-SSB (e.g., an SSB that is not a CD-SSB) to a CD-SSB. The frequency location to which the SSB is mapped may remain the same in the first interval and the second interval. Configuration information for the terminal to specify the first interval and / or the second interval may be signaled to the terminal from the base station. Configuration information regarding the first period value and the second period value may be signaled to the terminal from the base station. The length of the first interval may be a multiple of the first period value. In other words, the first section may include multiple first periods.

[0187] A terminal receiving a CD-SSB can derive measurement values ​​such as CSI, RRM, RLM, L1-RSRP, etc. by using both the CD-SSB based on the first period value and the CD-SSB based on the second period value. Alternatively, a terminal receiving a CD-SSB can derive measurement values ​​such as CSI, RRM, RLM, L1-RSRP, etc. by using only one of the CD-SSB based on the first period value and the CD-SSB based on the second period value. For example, a terminal receiving an on-demand SSB transmission indicator can receive either the CD-SSB based on the first period value or the CD-SSB based on the second period value. A legacy terminal can receive both the CD-SSB based on the first period value and the CD-SSB based on the second period value.

[0188] Alternatively, the on-demand SSB may be transmitted at a different frequency location than the periodic SSB. The on-demand SSB may be included in the same bandwidth portion as the periodic SSB, and the on-demand SSB may not overlap with the periodic SSB in the frequency domain. In this case, the on-demand SSB may be considered not to be a CD-SSB. For example, the on-demand SSB may be a NCD-SSB.

[0189] The above periodic SSB may be a cell-specific SSB (e.g., CD-SSB) and may not be correlated with a specific bandwidth portion (e.g., a DL bandwidth portion). If the activated DL bandwidth portion includes the periodic SSB, the terminal can receive the periodic SSB. The on-demand SSB may not be correlated with a specific bandwidth portion (e.g., a DL bandwidth portion), and the configuration of the on-demand SSB may be included in cell common information, and the on-demand SSB may be configured as a cell-specific SSB. If the cell-specific on-demand SSB is included in the activated DL bandwidth portion, the terminal can receive the cell-specific on-demand SSB. Alternatively, the on-demand SSB may be a UE-specific SSB or a bandwidth portion-specific SSB (e.g., NCD-SSB), and the on-demand SSB may be configured for a specific DL bandwidth portion, and the on-demand SSB may be correlated with the specific DL bandwidth portion. The UE-specific on-demand SSB may be received in a DL bandwidth portion that is correlated with the UE-specific on-demand SSB. In one cell (e.g., SCell), the cell-specific on-demand SSB and the UE-specific on-demand SSB may be configured together.

[0190] Both the periodic SSB and the on-demand SSB may be included in the active DL bandwidth portion. In a section where the on-demand SSB is transmitted or a section where the on-demand SSB is activated, the terminal may receive either the periodic SSB or the on-demand SSB. For example, the terminal may receive the on-demand SSB in the section and may omit a reception operation for the periodic SSB. The transmission period of the on-demand SSB may be a multiple or a divisor of the transmission period of the periodic SSB. The terminal may not expect the periodic SSB and the on-demand SSB to overlap in the time domain. In other words, the on-demand SSB may not be mapped to a half radio frame to which the periodic SSB is mapped, and the periodic SSB may not be mapped to a half radio frame to which the on-demand SSB is mapped. Alternatively, the periodic SSB and the on-demand SSB may overlap in time. In this case, the periodic SSB and the on-demand SSB may have the same transmission pattern (e.g., the same ssb-PositionsInBurst), and the periodic SSB and the on-demand SSB may completely overlap each other. Alternatively, the set of actually transmitted periodic SSB(s) may be a subset of the set of actually transmitted on-demand SSB(s). In this situation, the terminal may regard the SSB received in the overlapping period as a periodic SSB (or an on-demand SSB), and may expect to receive configuration information regarding a CORESET 0 and a Type 0 PDCCH CSS set for SIB1 PDCCH monitoring through a PBCH (e.g., MIB) included in the SSB. Regardless of the above overlap, periodic SSBs and on-demand SSBs having the same SSB index can have a QCL relationship with each other.In other words, the terminal can apply the same receive beam to reception of periodic SSB and reception of on-demand SSB for the same SSB index.

[0191] The on-demand SSB may not be included in the currently active DL bandwidth portion. For example, the on-demand SSB may not be included in the DL bandwidth portion activated by the bandwidth portion switching instruction. In this case, the terminal may not receive the on-demand SSB in the active DL bandwidth portion. The terminal may receive the periodic SSB in the active DL bandwidth portion. If the periodic SSB (e.g., CD-SSB) is not included in the active DL bandwidth portion, the terminal may receive the NCD-SSB set for the active DL bandwidth portion in the active DL bandwidth portion.

[0192] As described above, in one cell (e.g., SCell), cell-specific periodic SSB and UE-specific periodic SSB can be configured together, and cell-specific on-demand SSB and UE-specific on-demand SSB can be configured together. In this situation, an activated DL bandwidth portion (e.g., a DL bandwidth portion activated by bandwidth portion switching) can include a cell-specific on-demand SSB, and the activated DL bandwidth portion may not include a cell-specific periodic SSB. A terminal can receive an on-demand SSB in the bandwidth portion. When a UE-specific periodic SSB associated with the bandwidth portion is configured, the terminal can receive the UE-specific periodic SSB together with the on-demand SSB in the bandwidth portion, or only the UE-specific periodic SSB. For another example, an activated DL bandwidth portion (e.g., a DL bandwidth portion activated by bandwidth portion switching) may include a cell-specific periodic SSB, and the activated DL bandwidth portion may not include a cell-specific on-demand SSB. The UE may receive the cell-specific SSB in the bandwidth portion. If a UE-specific on-demand SSB associated with the bandwidth portion is configured, the UE may receive the UE-specific on-demand SSB together with the periodic SSB in the bandwidth portion, or may receive only the UE-specific on-demand SSB.

[0193] In the above process, the pair of periodic SSBs and on-demand SSBs that are interrelated may be changed. For example, a periodic SSB may be interrelated with an on-demand SSB belonging to the same bandwidth portion, and a periodic SSB may be interrelated with another on-demand SSB other than the on-demand SSB as the bandwidth portion is switched. An on-demand SSB may be interrelated with a periodic SSB belonging to the same bandwidth portion, and an on-demand SSB may be interrelated with another periodic SSB other than the periodic SSB as the bandwidth portion is switched. The frequency resources of the paired periodic SSBs and the frequency resources of the on-demand SSBs may completely overlap in the frequency domain. Alternatively, the frequency resources of the paired periodic SSBs and the frequency resources of the on-demand SSBs may not overlap in the frequency domain.

[0194] In the above embodiment, CD-SSB may broadly mean an SSB configured by cell-specific configuration information (e.g., an SSB configured by sub-parameters such as servingCellConfigCommon and servingCellConfigSIB). Simultaneously or separately from the above embodiment, CD-SSB may mean an SSB in which the terminal receives SIB1 corresponding to the SSB together. The terminal may receive CD-SSB and SIB1 together. Alternatively, the terminal may receive CD-SSB without SIB1. For example, as in the above embodiment, CD-SSB in SCell may not include a configuration for SIB1 transmission corresponding to the CD-SSB. When the on-demand SSB is a CD-SSB, the on-demand SSB may be configured in the terminal by cell-specific configuration information (e.g., servingCellConfigCommon and servingCellConfigSIB). Cell-specific configuration information may include both on-demand SSB configuration information and periodic SSB configuration information.

[0195] An inclusive relationship may exist between periodic SSB and on-demand SSB. For example, SSB resources constituting on-demand SSB may include SSB resources constituting periodic SSB. Alternatively, SSB resources constituting periodic SSB may include SSB resources constituting on-demand SSB. The inclusive relationship may exist in a period in which on-demand SSB is activated. The inclusive relationship may be limited in the time domain. In other words, periodic SSB and on-demand SSB may have an inclusive relationship in the time domain, and periodic SSB and on-demand SSB may be transmitted on different frequency resources. In the above-described embodiment, periodic SSB and on-demand SSB may be monitored or received within the same SMTC window. In another embodiment, the terminal may receive a configuration of multiple SMTC windows, and may receive periodic SSB and on-demand SSB in different SMTC windows.

[0196] An SMTC window may include a cell-specific SMTC window and a UE-specific SMTC window (e.g., a bandwidth portion-specific SMTC window). Similar to the above-described embodiment, an SMTC window may or may not have a correlation with a DL bandwidth portion. When a DL bandwidth portion correlated with an SMTC window is activated or a DL bandwidth portion to which the SMTC window belongs is activated, the SMTC window may be used for SSB reception. A terminal may receive multiple SSBs using multiple SMTC windows in an active bandwidth portion. The terminal may switch the SMTC window according to a bandwidth portion switching operation.

[0197] When a terminal receives both periodic SSB and on-demand SSB in an active bandwidth portion, the terminal may consider both periodic SSB and on-demand SSB when determining the validity of each RO. The terminal may consider an RO mapped to a symbol that is at least N symbols later than a periodic SSB resource and / or an RO mapped to a symbol that is N symbols later than an on-demand SSB as a valid RO. In addition, the terminal may consider an RO mapped to symbol(s) preceding a periodic SSB resource in the same slot as a periodic SSB resource as an invalid RO, and the terminal may consider an RO mapped to symbol(s) preceding an on-demand SSB resource in the same slot as an on-demand SSB resource as an invalid RO. When multiple on-demand SSBs are configured for the terminal, the RO validity determination procedure may be performed for all configured on-demand SSBs. Based on the above-described operation, the SSB-RO mapping relationship can remain the same even when the on-demand SSB is dynamically changed. The terminal can transmit the preamble in the valid RO. The value of N can be determined based on the frequency band, whether it is a licensed band, the subcarrier spacing, etc. N can be an integer greater than or equal to 0. For example, N can be 0 or 2.

[0198] Based on the above inclusion relationship, the terminal can perform an operation to determine the validity of the RO based on the SSB with a higher transmission density. For example, if the SSB resources that constitute the on-demand SSB include the SSB resources that constitute the periodic SSB, the terminal can check the validity of each RO based on the on-demand SSB resources. The above-described operation can be performed separately from the beam measurement operation, the beam reporting operation, the CSI measurement operation, and / or the CSI reporting operation.

[0199] In the proposed SSB dynamic adaptation method, the terminal can receive system information (e.g., SIB1) at the same period as the changed SSB transmission period. In other words, the terminal can equally apply the SSB period value (e.g., SSB transmission period value) indicated by the base station to SIB1. In the present disclosure, receiving SIB1 may mean an operation of monitoring SIB1 PDCCH and / or an operation of receiving SIB1 PDSCH. The time point at which the period value of SIB1 changes may coincide with the time point at which the period value of the SSB corresponding to the SIB1 changes. The SSB may be a CD-SSB, and the cell in which the SSB and SIB1 are transmitted may be a PCell. In other words, when the periods of a plurality of SSBs are dynamically controlled, the period value of SIB1 may be adapted based on the period value of a CD-SSB among the plurality of SSBs.

[0200] Alternatively, the SIB1 period value (e.g., the SIB1 transmission period value) can be signaled to the UE independently from the SSB period value. The SIB1 period value can be an example of one of the controllable SIB1 transmission parameters. In addition to the SIB1 period value, SIB1 control information (e.g., controllable SIB1 transmission parameters), such as a type 0-PDCCH search space set (e.g., the location of the PDCCH monitoring occasion) and an associated CORESET, can be dynamically signaled together with the SSB control information. For the NES operation of the cell, the SIB1 control information can include information indicating that SIB1 will be transmitted during a specific time interval, information indicating that SIB1 will not be transmitted during a specific time interval, etc. The UE can determine a time interval in which it receives or does not receive SIB1 based on the information. In a time interval in which the UE does not receive SIB1, the cell can skip the SIB1 transmission operation. In other words, the cell can operate in NES mode. SIB1 control information can be transmitted to the terminal by being included in DCI or MAC CE for SSB adaptation indication.

[0201] The base station may omit SIB1 transmission in some periods based on the SIB1 period value assumed by the terminal. However, the base station shall transmit SIB1 at least once every T ms. The value of T may be predefined in the technical specification. Alternatively, the value of T may be determined by a signaling procedure from the base station to the terminal. For example, T may be 160 ms. The SSB period value dynamically indicated to the terminal by the SSB adaptation indicator may not exceed T ms, and the SSB period value may be a divisor of T ms. According to the above-described method, the minimum period value of SIB1 (e.g., the period at which the terminal monitors the SIB1 PDCCH) may be equal to the SSB period value, and the maximum period value of SIB1 (e.g., the period at which the base station must transmit SIB1 at least once) may be fixed to T.

[0202] The operations of the method according to the embodiments of the present disclosure can be implemented as a computer-readable program or code on a computer-readable recording medium. A computer-readable recording medium includes any type of recording device that stores information readable by a computer system. Furthermore, a computer-readable recording medium can be distributed across network-connected computer systems, allowing the computer-readable program or code to be stored and executed in a distributed manner.

[0203] Additionally, the computer-readable recording medium may include hardware devices specifically configured to store and execute program instructions, such as ROM, RAM, flash memory, etc. The program instructions may include not only machine language codes produced by a compiler, but also high-level language codes that can be executed by a computer using an interpreter, etc.

[0204] While some aspects of the present disclosure have been described in the context of a device, they may also represent a description of 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 as 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 or more of the most significant method steps may be performed by such a device.

[0205] In 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 embodiments, the field-programmable gate array may operate in conjunction with a microprocessor to perform one of the methods described herein. In general, the methods are preferably performed by some hardware device.

[0206] Although the present disclosure has been described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various modifications and changes may be made to the present disclosure without departing from the spirit and scope of the present disclosure as set forth in the claims below.

Claims

1. As a terminal method, A step of receiving a first message including setting information of a plurality of period values ​​for an SSB (synchronization signal block) from a base station; Receiving a second message from the base station, the second message including information indicating one of the plurality of periodic values; and A step of performing a receiving operation for the SSB based on the one cycle value, Terminal method.

2. In claim 1, The above plurality of periodic values ​​include a legacy periodic value set by a legacy parameter and one or more additional periodic values ​​set by a new parameter. Terminal method.

3. In claim 2, A time offset for each of the one or more additional periodic values ​​is set in the terminal, and based on the one periodic value indicated by the second message being one of the one or more additional periodic values, the receiving operation for the SSB is performed in a time resource determined based on the one periodic value and the time offset corresponding to the one periodic value. Terminal method.

4. In claim 1, The SSB resource sets formed based on the above plurality of periodic values ​​have an inclusive relationship, and the SSB resources formed based on a long periodic value among the plurality of periodic values ​​are a subset of the SSB resources formed based on a short periodic value among the plurality of periodic values. Terminal method.

5. In claim 1, Based on the second message, the period value of the SSB is dynamically changed, and even in a situation where the period value of the SSB is dynamically changed, the receiving operation for the SSB is performed in one SMTC (SSB measurement time configuration) window. Terminal method.

6. In claim 1, The receiving operation for the SSB is performed from the earliest SSB cycle after the time of receiving the second message or the time of applying the one cycle value, and the earliest SSB cycle is the earliest SSB cycle among the SSB cycles determined based on the one cycle value. Terminal method.

7. In claim 1, Further comprising a step of performing a receiving operation for the SSB based on a period value indicated before the one period value during the SSB period belonging to the time of receiving the second message or the time of applying the one period value. Terminal method.

8. In claim 1, The second message is received on the first carrier, and the receiving operation for the SSB based on the one period value is performed on the second carrier, and the first carrier is different from the second carrier. Terminal method.

9. In claim 8, Based on the fact that the first numerology of the first carrier is different from the second numerology of the second carrier, the point in time at which the one period value is applied is determined based on the first numerology. Terminal method.

10. In claim 1, The first message is an RRC (radio resource control) message, and the second message is DCI (downlink control information). Terminal method.

11. As a method of base station, A step of transmitting a first message including setting information of a plurality of period values ​​for an SSB (synchronization signal block) to a terminal; A step of transmitting a second message including information indicating one of the plurality of periodic values ​​to the terminal; and A step of transmitting the SSB to the terminal based on the one cycle value, Base station method.

12. In claim 11, The above plurality of periodic values ​​include a legacy periodic value set by a legacy parameter and one or more additional periodic values ​​set by a new parameter. Base station method.

13. In claim 12, A time offset for each of the one or more additional periodic values ​​is set in the terminal, and based on the one periodic value indicated by the second message being one of the one or more additional periodic values, the SSB is transmitted in a time resource determined based on the one periodic value and the time offset corresponding to the one periodic value. Base station method.

14. In claim 11, The SSB resource sets formed based on the above plurality of periodic values ​​have an inclusive relationship, and the SSB resources formed based on a long periodic value among the plurality of periodic values ​​are a subset of the SSB resources formed based on a short periodic value among the plurality of periodic values. Base station method.

15. In claim 11, Based on the second message, the period value of the SSB is dynamically changed, and even in a situation where the period value of the SSB is dynamically changed, the SSB is transmitted in one SMTC (SSB measurement time configuration) window. Base station method.

16. In claim 11, The above SSB is transmitted from the earliest SSB cycle after the time of transmission of the second message or the time of application of the one cycle value, and the earliest SSB cycle is the earliest SSB cycle among the SSB cycles determined based on the one cycle value. Base station method.

17. In claim 11, Further comprising a step of transmitting the SSB to the terminal based on a period value indicated before the one period value during the SSB period belonging to the time of transmission of the second message or the time of application of the one period value. Base station method.

18. In claim 11, The second message is transmitted on a first carrier, and the SSB based on the one period value is transmitted on a second carrier, and the first carrier is different from the second carrier. Base station method.

19. In claim 18, Based on the fact that the first numerology of the first carrier is different from the second numerology of the second carrier, the point in time at which the one period value is applied is determined based on the first numerology. Base station method.

20. In claim 11, The first message is an RRC (radio resource control) message, and the second message is DCI (downlink control information). Base station method.

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