Method performed by terminal or network in wireless communication system, and device therefor

Abstract

A method performed by a terminal according to an embodiment of the present disclosure may comprise: receiving a synchronization signal block (SSB) configuration for a second cell supporting adaptation of SSB transmission, through higher layer signaling in at least one of a first cell and the second cell; receiving a downlink signal from at least one of the first cell and the second cell; and determining whether the SSB transmission is performed on the second cell, on the basis of the received downlink signal, wherein the terminal receives an SSB of the second cell by using the SSB configuration on the basis of the determination that the SSB transmission is performed on the second cell.

Description

Method performed by a terminal or network in a wireless communication system and device therefor

[0001] The present disclosure relates to a wireless communication system, and more particularly, to a method and device for performing wireless communication between terminals or networks in a wireless communication system.

[0002] The 5G mobile communications system, the successor to LTE (long-term evolution), is a new, clean-slate mobile communications system characterized by high performance, low latency, and high availability. 5G NR can utilize all available spectrum resources, from low-frequency bands below 1 GHz, to intermediate-frequency bands between 1 GHz and 10 GHz, and high-frequency (millimeter wave) bands above 24 GHz. 6G mobile communications systems are being developed based on the underlying technologies of 5G mobile communications.

[0003] The existing 5G standard (NR) defines SSB-less cells that do not provide SSB, and the cell that provides a synchronization reference for the SSB-less cell is referred to as a reference cell. A UE can determine that a cell is SSB-less if it does not provide an SSB configuration or an SSB measurement timing configuration (SMTC).

[0004] Recently, the standardization of on-demand SSB (On-Demand SSB) is being pursued as one of the topics for Network Energy Saving (NES). On-demand SSB standardization involves three methods: 1) a terminal requests SSB transmission from a base station by transmitting an uplink signal / channel; 2) requesting SSB transmission through an interface or backhaul signaling between base stations; and 3) signaling whether SSB transmission for a given Scell ​​is to be enabled through Scell ​​activation / deactivation signaling.

[0005] The technical task to be achieved in the present disclosure is to provide a method and device for efficiently performing a wireless signal transmission and reception process. As an example, a method for signaling configuration information for a cell supporting OD SSB to save network energy between a terminal and a network, and OD SSB-related operations based on the signaling method are provided.

[0006] In addition to the technical challenges described above, other technical challenges can be inferred from the description below.

[0007] According to one aspect of the present disclosure, a method performed by a terminal includes receiving, through upper layer signaling in at least one of a first cell and a second cell, an SSB configuration for a second cell that supports adaptation of SSB transmission; receiving a downlink signal in at least one of the first cell and the second cell; and determining whether the SSB transmission is performed on the second cell based on the received downlink signal, wherein the terminal can receive the SSB of the second cell using the SSB configuration based on determining that the SSB transmission is performed on the second cell.

[0008] The terminal may ignore the SSB setting and skip SSB reception on the second cell based on a determination that the SSB transmission is not performed on the second cell.

[0009] The above downlink signal may be related to RRC (radio resource control) signaling or MAC-CE (medium access control - control element) signaling for activation of the second cell.

[0010] The above SSB setting may include at least one of SSB index information, SSB period information, SSB frequency information, and SSB subcarrier spacing information.

[0011] In the second cell, a first SSB to which the adaptation of the SSB transmission is applied and a second SSB that is periodically transmitted without the adaptation of the SSB transmission can be set.

[0012] The above SSB setting and the above downlink signal may be related to the first SSB.

[0013] The terminal may perform measurements related to the second cell based on at least one SSB. The at least one SSB may include only the SSB of the second cell based on the fact that a reference cell for the second cell is not provided. The at least one SSB may further include the SSB of the reference cell in addition to the SSB of the second cell based on the fact that the reference cell for the second cell is provided.

[0014] Whether a reference cell is provided for the second cell can be explicitly indicated via network signaling.

[0015] The terminal may transmit an uplink signal for requesting the SSB transmission on the second cell through at least one of the first cell or the second cell. The downlink signal may be received as a response to the uplink signal.

[0016] The second cell may be a SCell (secondary cell). The first cell may be a PCell (primary cell), a reference cell for the second cell, or an Scell ​​different from the second cell.

[0017] According to another aspect of the present disclosure, a non-transitory computer-readable recording medium having recorded thereon a program for performing the method described above may be provided.

[0018] According to another aspect of the present disclosure, a device comprises a memory configured to store instructions; and a processor configured to perform operations by executing the instructions, wherein the operations of the processor include receiving, through upper layer signaling in at least one of a first cell and a second cell, an SSB configuration for a second cell that supports adaptation of SSB transmission; receiving a downlink signal in at least one of the first cell and the second cell; and determining whether the SSB transmission is performed on the second cell based on the received downlink signal, wherein the device can receive an SSB of the second cell using the SSB configuration based on determining that the SSB transmission is performed on the second cell.

[0019] The above device may further include a transmitter and receiver.

[0020] The above device may be a terminal operating in a wireless communication system.

[0021] The above device may be a processing device configured to control a terminal operating in a wireless communication system.

[0022] According to another aspect of the present disclosure, a method performed by a base station includes transmitting, through upper layer signaling in at least one of a first cell and a second cell, an SSB configuration for a second cell that supports adaptation of SSB transmission; determining whether to perform the SSB transmission on the second cell; and transmitting, through at least one of the first cell and the second cell, a downlink signal indicating whether to perform the SSB transmission on the second cell, wherein the base station can transmit an SSB of the second cell using the SSB configuration based on determining that the SSB transmission will be performed on the second cell.

[0023] According to another aspect of the present disclosure, a base station comprises a memory configured to store instructions; and a processor configured to perform operations by executing the instructions, wherein the operations of the processor include transmitting, through upper layer signaling in at least one of a first cell and a second cell, an SSB configuration for a second cell that supports adaptation of SSB transmission; determining whether to perform the SSB transmission on the second cell; and transmitting, through at least one of the first cell and the second cell, a downlink signal indicating whether to perform the SSB transmission on the second cell, wherein the base station can transmit an SSB of the second cell using the SSB configuration based on determining that the SSB transmission will be performed on the second cell.

[0024] According to the present disclosure, signal transmission and reception can be efficiently performed in a wireless communication system. For example, network energy can be saved through cells supporting OD-SSB, and a terminal can efficiently obtain SSB configuration and SMTC information for OD-SSB-supporting cells.

[0025] In addition to the technical effects described above, other technical effects can be inferred from the description below.

[0026] Figure 1 illustrates a flexible network topology to which some examples of this specification may be applied.

[0027] FIG. 2 illustrates an example of a communication system applicable to the present disclosure.

[0028] FIG. 3 illustrates an example of a wireless device applicable to the present disclosure.

[0029] FIG. 4 illustrates a communication procedure between a first node (e.g., a terminal) and a second node (e.g., a base station) applicable to the present disclosure.

[0030] Figure 5 illustrates a general functional architecture for an AI / ML model.

[0031] Figure 6 illustrates a communication procedure between a first node (e.g., terminal) and a second node (e.g., base station) to which an AI / ML model is applied.

[0032] FIG. 7 illustrates an electromagnetic spectrum according to one embodiment of the present disclosure.

[0033] FIG. 8 illustrates an example of a procedure for transmitting system information for THz communication to which the present disclosure applies.

[0034] Figure 9 illustrates a beam management procedure applicable to the present disclosure.

[0035] FIG. 10 illustrates an example of a sensing operation according to one embodiment of the present disclosure.

[0036] FIG. 11 illustrates time / frequency resources for sensing operations according to one embodiment of the present specification.

[0037] FIG. 12 illustrates a procedure related to a sensing operation according to one embodiment of the present specification.

[0038] Figure 13 illustrates an example of the operation procedure of a base station supporting NES technology.

[0039] Figure 14 illustrates an example of a procedure for cell DTX / DRX operation.

[0040] Figure 15 illustrates an example of a procedure for CA operation using SSB-less SCell.

[0041] Figure 16 illustrates an example of a conditional handover (CHO) procedure.

[0042] Figure 17 shows an example of on-demand SSB transmission.

[0043] Figure 18 illustrates an example of SSB transmission of a base station operating multiple frequency bands.

[0044] Figure 19 illustrates the operation of a terminal and a base station according to one embodiment.

[0045] FIG. 20 illustrates a flow of a method performed by a terminal according to one embodiment.

[0046] FIG. 21 illustrates a flow of a method performed by a base station according to one embodiment.

[0047] As used herein, "A or B" can mean "only A," "only B," or "both A and B." In other words, as used herein, "A or B" can be interpreted as "A and / or B." For example, as used herein, "A, B or C" can mean "only A," "only B," "only C," or "any combination of A, B and C."

[0048] As used herein, a slash ( / ) or a comma can mean "and / or." For example, "A / B" can mean "A and / or B." Accordingly, "A / B" can mean "only A," "only B," or "both A and B." For example, "A, B, C" can mean "A, B, or C."

[0049] In this specification, "at least one of A and B" may mean "only A", "only B" or "both A and B". Additionally, in this specification, the expressions "at least one of A or B" or "at least one of A and / or B" may be interpreted identically to "at least one of A and B".

[0050] Additionally, in this specification, “at least one of A, B and C” can mean “only A,” “only B,” “only C,” or “any combination of A, B and C.” Additionally, “at least one of A, B or C” or “at least one of A, B and / or C” can mean “at least one of A, B and C.”

[0051] Additionally, parentheses used herein may mean "for example." Specifically, when "control information (ABC)" is indicated, "ABC" may be described as an example of "control information." For example, "control information" may include DEF as another example. In other words, "control information" in this specification is not limited to "ABC," and "ABC" may be described as an example of "control information." Furthermore, even when indicated as "control information (i.e., ABC)," "ABC" may be described as an example of "control information."

[0052] Additionally, in this specification, terms such as “first,” “second,” etc. are used only for the purpose of distinguishing one component from another component and are not used to limit the components, and do not limit the order or importance between the components unless specifically limited. Accordingly, a first component in one embodiment of this specification may be referred to as a second component in another embodiment, and similarly, a second component in one embodiment may be referred to as a first component in another embodiment.

[0053] In the following explanation, ‘when, if, in case of’ can be replaced with ‘based on’.

[0054] Technical features individually described in a single drawing in this specification may be implemented individually or simultaneously.

[0055] In this specification, a terminal is a user equipment (UE) or a consumer-side device, and may also be referred to as a base station / second node / IAB node / first node that receives / transmits signals from / to a Transmission-Reception Point (TRP). A terminal may correspond to a physical node or a logical node. A terminal may correspond to an endpoint on the user side, or may correspond to an intermediate point between other endpoints. In communication between two points that are not limited to endpoints (including one-to-one / many-to-one / one-to-many / many-to-many communication), a terminal may correspond to a served node. A terminal may be a node with a fixed location, or a node with an unfixed location (or mobile).

[0056] In this specification, a base station (BS) is a device on the network side, and may also be called a second node / IAB node / x-NodeB (x-NodeB, x may be an abbreviation related to radio access technology (RAT)) / Transmission-Reception Point (TRP). A BS may correspond to a physical node or a logical node. A BS may correspond to an endpoint on the network side, or may correspond to an intermediate point between other endpoints. In communication between two points that are not limited to endpoints (including one-to-one / many-to-one / one-to-many / many-to-many communication), a BS may correspond to a serving node. A BS may be a node with a fixed location, or a node with an unfixed location.

[0057] In this specification, higher layer parameters may be set for the terminal, preset, or predefined. For example, the base station may transmit higher layer parameters to the terminal. For example, the terminal may transmit parameters such as capabilities to the base station as higher layer parameters. For example, the higher layer parameters may be transmitted via radio resource control (RRC) signaling or medium access control (MAC) signaling.

[0058] In this specification, the information / state / parameter being “configured or pre-configured” can be interpreted as the information / state / parameter being provided / pre-provided to the terminal through pre-defined signaling (e.g., SIB, MAC, RRC) from the base station. In this specification, the information / state / parameter being “defined or pre-defined” can be interpreted as the information / state / parameter being known in advance or pre-stored at the base station and the terminal without signaling between the base station and the terminal.

[0059] The technology described in this specification can be used in various wireless communication systems such as CDMA (code division multiple access), FDMA (frequency division multiple access), TDMA (time division multiple access), OFDMA (orthogonal frequency division multiple access), and SC-FDMA (single carrier frequency division multiple access). CDMA can be implemented with wireless technologies such as UTRA (universal terrestrial radio access) or CDMA2000. TDMA can be implemented with wireless technologies such as GSM (global system for mobile communications) / GPRS (general packet radio service) / EDGE (enhanced data rates for GSM evolution). OFDMA can be implemented with wireless technologies such as IEEE (Institute of Electrical and Electronics Engineers) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, E-UTRA (evolved UTRA), LTE (long term evolution), and 5G NR.

[0060] The technology described in this specification can be implemented with 6G wireless technology and applied to various 6G systems. For example, the 6G system can have key factors such as enhanced mobile broadband (eMBB), ultra-reliable low latency communications (URLLC), massive machine-type communication (mMTC), artificial intelligence (AI) integrated communication, tactile internet, high throughput, high network capacity, high energy efficiency, low backhaul and access network congestion, and enhanced data security.

[0061] <Symbols, Abbreviations, Terms>

[0062] - PDCCH: Physical Downlink Control CHannel

[0063] - DCI: Downlink Control Information

[0064] - PDSCH: Physical Downlink Shared CHannel

[0065] - PUSCH: Physical Uplink Shared CHannel

[0066] - CSI: Channel state information

[0067] - RRM: Radio resource management

[0068] - SCS: Sub-carrier spacing

[0069] - RLM: Radio link monitoring

[0070] - DCI: Downlink Control Information

[0071] - CAP: Channel Access Procedure

[0072] - Ucell: Unlicensed cell

[0073] - TBS: Transport Block Size

[0074] - TDRA: Time Domain Resource Allocation

[0075] - SLIV: Starting and Length Indicator Value (This is an indicator value for the starting symbol index and number of symbols within the slot of the PDSCH and / or PUSCH, and can be set as a component of the entry that constitutes the TDRA field within the PDCCH that schedules the corresponding PDSCH and / or PUSCH.)

[0076] - BWP: BandWidth Part (can be composed of consecutive resource blocks (RBs) on the frequency axis and can correspond to one numerology (e.g., sub-carrier spacing, CP length, slot / mini-slot duration). In addition, multiple BWPs can be configured on one carrier (the number of BWPs per carrier can also be limited), but the number of activated BWPs can be limited to a part of it (e.g., 1) per carrier.)

[0077] - CORESET: COntrol REsourse SET (refers to the time-frequency resource area where PDCCH can be transmitted, and the number of CORESETs per BWP may be limited.)

[0078] - REG: Resource element group

[0079] - SFI: Slot Format Indicator (An indicator indicating the symbol level DL / UL direction within a specific slot(s), transmitted through the group common PDCCH.)

[0080] - COT: Channel occupancy time

[0081] - SPS: Semi-persistent scheduling

[0082] - QCL: Quasi-Co-Location (QCL relationship between two reference signals means that QCL parameters such as Doppler shift, Doppler spread, average delay, delay spread, and Spatial Rx parameter obtained from one reference signal can be applied to another reference signal (or antenna port(s) of the corresponding RS). In the NR system, four QCL types are defined as follows. 'typeA': {Doppler shift, Doppler spread, average delay, delay spread}, 'typeB': {Doppler shift, Doppler spread}, 'typeC': {Doppler shift, average delay}, 'typeD': {Spatial Rx parameter} For any DL RS antenna port(s), the first DL RS is set as a reference for QCL type X (X=A, B, C, or D), and additionally, the second DL RS is set as a reference for QCL type Y (Y=A, B, C, or D but X≠Y) ) can be set as a reference to

[0083] - TCI: Transmission Configuration Indication (A TCI state includes the QCL relationship between one or more DL RSs, such as DM-RS ports of the PDSCH, the DM-RS port of PDCCH, or the CSI-RS port(s) of a CSI-RS resource. For the 'Transmission Configuration Indication' field in the DCI that schedules the PDSCH, the TCI state index corresponding to each code point that constitutes the field is activated by the MAC CE, and the TCI state setting for each TCI state index is set through RRC signaling. In the Rel-16 NR system, the TCI state is set between DL RSs, but in future releases, setting between DL RS and UL RS or UL RS and UL RS may be allowed. Examples of UL RSs include SRS, PUSCH DM-RS, and PUCCH DM-RS.)

[0084] - SRI: SRS resource indicator (Indicates one of the SRS resource index values ​​set in the 'SRS resource indicator' among the fields in the DCI that schedules the PUSCH. When transmitting a PUSCH, the UE can transmit the PUSCH using the same spatial domain transmission filter used for transmitting and receiving the reference signal linked to the corresponding SRS resource. At this time, the reference RS is set by RRC signaling through the SRS-SpatialRelationInfo parameter for each SRS resource, and SS / PBCH block, CSI-RS, or SRS can be set as the reference RS.)

[0085] - TRP: Transmission and Reception Point

[0086] - TAG: Timing advance group

[0087] - PBCH: Physical Broadcast Channel

[0088] - SS: Synchronization Signal

[0089] - SSB: PBCH / SS block

[0090] Figure 1 illustrates a flexible network topology to which some examples of this specification may be applied.

[0091] To compensate for incomplete network coverage areas, a network topology that allows for more flexible and resilient split radio access networks (RANs) may be considered. For this purpose, various nodes, such as IAB nodes, relays, and RF repeaters, as illustrated in the example in Figure 1, may be applied, or NTNs may be integrated. For example, an IAB node may correspond to a node that provides wireless backhaul. For example, a relay may refer to any intermediate point, or in the case of a sidelink relay where a terminal functions as a relay, it may collectively refer to a terminal-to-network (U2N) relay and a terminal-to-terminal (U2U) relay. For example, an RF repeater may correspond to a node that simply performs the function of signal amplification and forwarding, while a network-controlled repeater may not only amplify and forward signals but also adjust transmission and reception settings based on information provided by the network. For example, an NTN node may correspond to a satellite or aircraft that provides NTN coverage that is difficult for terrestrial networks to provide. In addition to these examples, various intermediate points can be introduced to improve the network topology.

[0092] Referring to Figure 1, a split RAN can support the division of a base station into a centralized unit (CU) and one or more distributed units (DUs). The CU and DU can correspond to logical units. The CU can be further divided into a control plane (CP) portion and one or more user plane (UP) portions. Since a failure in the CU-CP affects not only the CU-UP but also the DUs, various intermediate points can be introduced to compensate for this.

[0093] An intermediate point may correspond to a terminal or a base station, depending on its relationship to other nodes. For example, an IAB node may include a mobile-termination (MT) portion and a unit (DU). The MT may connect the IAB node to a donor node. The unit (DU) of an IAB node may serve other terminals or connect to other IAB nodes to provide multi-hop wireless backhaul to the terminal. In other words, an IAB node may correspond to a base station in its relationship to a user-side node, and to a terminal in its relationship to a network-side node.

[0094] In some examples of this specification, the description of a terminal can be equally applied not only to a user-side endpoint, but also to an intermediate point corresponding to a terminal in a relative relationship with a network-side endpoint. Similarly, in some examples of this specification, the description of a base station can be equally applied not only to a network-side endpoint, but also to an intermediate point corresponding to a base station in a relative relationship with a user-side endpoint. However, in most cases where there is no additional description of the operations of three or more entities, the communicating entities in this specification are briefly described as terminals and / or base stations (or first nodes and / or second nodes), and the terms terminal and / or base stations (or first nodes and / or second nodes) are interpreted to include / replace any endpoint or any intermediate point in relation to other nodes.

[0095] That is, in some examples of this specification, for the sake of simplicity of explanation, the subjects of the operation may be referred to as a base station and / or a terminal (or a first node and / or a second node). In addition, the terms base station and / or terminal (or a first node and / or a second node) may also be interpreted / replaced as in the following examples: For example, the base station (or a first node) and the terminal (or a second node) may respectively correspond to the first endpoint and the second endpoint; may respectively correspond to the endpoint and the intermediate point; may respectively correspond to the intermediate point and the endpoint; or may respectively correspond to the first intermediate point and the second intermediate point.

[0096] In this specification, there may be zero or more intermediate points between the base station and the terminal. If intermediate points exist, they may be IAB nodes, relays, RF repeaters, NTN (non-terrestrial network) nodes, or nodes supporting other functions. An intermediate point may be a node with a fixed location or a node with an unfixed location.

[0097] Figure 2 illustrates a communication system applicable to the present disclosure.

[0098] The communication system (100) of FIG. 2 includes a wireless device (110), a network device (120), and a network (130). Here, the wireless device (110) refers to a device that performs communication using a wireless access technology (e.g., LTE, LTE-A, LTE-A pro, NR, 5G, 5G-A, 6G), and may be referred to as a communication / wireless / 5G / 6G device. Although not limited thereto, the wireless device (110) may include a robot (110a), a vehicle (110b-1, 110b-2), an XR (extended reality) device (110c), a hand-held device (110d), a home appliance (110e), an IoT (Internet of Things) device (110f), and an AI (artificial intelligence) device / server (110g). For example, the vehicle may include a vehicle equipped with a wireless communication function, an autonomous vehicle, a vehicle capable of performing vehicle-to-vehicle communication, etc. Here, the vehicle (110b-1, 110b-2) may include an unmanned aerial vehicle (UAV) (e.g., a drone). The XR device (110c) includes an augmented reality (AR) / virtual reality (VR) / mixed reality (MR) device, and may be implemented in the form of a head-mounted device (HMD), a head-up display (HUD) equipped in a vehicle, a television, a smartphone, a computer, a wearable device, a home appliance, a digital signage, a vehicle, a robot, etc. The portable device (110d) may include a smartphone, a smart pad, a wearable device (e.g., a smart watch, smart glasses), a computer (e.g., a laptop, etc.), etc. The home appliance (110e) may include a TV, a refrigerator, a washing machine, etc. The IoT device (110f) may include a sensor, a smart meter, etc. The wireless device (110) may correspond to a terminal (or first node) or an intermediate point.The network device (120) may correspond to a base station (or second node) or another intermediate point. For example, the network device (120) may also be implemented as a wireless device (110), and a specific wireless device (120a) may act as a network device (120) to another wireless device (110).

[0099] Wireless devices (110a to 110f) can be connected to a network (130) via a network device (120). AI technology can be applied to the wireless devices (110a to 110f), and the wireless devices (110a to 110f) can be connected to an AI server (110g) via a network (130). The network (130) can be configured using a 3G network, a 4G (e.g., LTE) network, a 5G (e.g., NR), or a 6G network. The wireless devices (110a to 110f) can communicate with each other via the network device (120) / network (130), but can also communicate directly (e.g., sidelink communication) without going through the network device (120) / network (130). For example, vehicles (110b-1, 110b-2) can communicate directly (e.g., V2V (vehicle to vehicle) / V2X (vehicle to everything) communication). Additionally, IoT devices (110f) (e.g., sensors) can communicate directly with other IoT devices (e.g., sensors) or other wireless devices (110a to 110f).

[0100] Wireless communication / connection (150a, 150b, 150c) can be established between wireless devices (110a to 110f) / network devices (120), network devices (120) / network devices (120). Here, the wireless communication / connection can be established through various wireless access technologies such as uplink / downlink communication (150a), sidelink communication (150b) (or D2D communication), and communication between network devices (150c) (e.g., relay, IAB (integrated access backhaul)). Through the wireless communication / connection (150a, 150b, 150c), the wireless device and the network device / wireless device, and the network device and the network device can transmit / receive wireless signals to each other. For example, the wireless communication / connection (150a, 150b, 150c) can transmit / receive signals through various physical channels. To this end, based on various descriptions of the present disclosure, at least some of various configuration information setting processes for transmitting / receiving wireless signals, various signal processing processes (e.g., channel encoding / decoding, modulation / demodulation, resource mapping / demapping, etc.), resource allocation processes, etc. may be performed.

[0101] FIG. 3 illustrates an example of a wireless device applicable to the present disclosure.

[0102] Referring to FIG. 3, the wireless device (200) can transmit and receive wireless signals via various wireless access technologies (e.g., LTE, LTE-A, LTE-A pro, NR, 5G, 5G-A, 6G). The wireless device (200) includes at least one processor (202) and at least one memory (204), and may additionally include at least one transceiver (206) and / or at least one antenna (208).

[0103] The processor (202) controls the memory (204) and / or the transceiver (206), and may be configured to implement the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in this document. For example, the processor (202) may process information in the memory (204) to generate first information / signal, and then transmit a wireless signal including the first information / signal via the transceiver (206). In addition, the processor (202) may receive a wireless signal including second information / signal via the transceiver (206), and then store information obtained from signal processing of the second information / signal in the memory (204). The memory (204) may be connected to the processor (202) and may store various information related to the operation of the processor (202). For example, the memory (204) may store software code including instructions for performing some or all of the processes controlled by the processor (202), or for performing the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed herein. Here, the processor (202) and the memory (204) may be part of a communication modem / circuit / chip designed to implement wireless communication technology. The transceiver (206) may be connected to the processor (202) and may transmit and / or receive wireless signals via at least one antenna (208). The transceiver (206) may include a transmitter and / or a receiver. The transceiver (206) may be used interchangeably with an RF (radio frequency) unit. In the present disclosure, a wireless device may also mean a communication modem / circuit / chip.

[0104] Hereinafter, the hardware elements of the wireless device (200) will be described in more detail. Although not limited thereto, at least one protocol layer may be implemented by at least one processor (202). For example, at least one processor (202) may implement at least one layer (e.g., a functional layer such as physical (PHY), media access control (MAC), radio link control (RLC), packet data convergence protocol (PDCP), radio resource control (RRC), and service data adaptation protocol (SDAP)). At least one processor (202) may generate at least one Protocol Data Unit (PDU) and / or at least one Service Data Unit (SDU) according to the descriptions, functions, procedures, proposals, methods, and / or operation flowcharts disclosed in this document. At least one processor (202) may generate a message, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or operation flowcharts disclosed in this document. At least one processor (202) can generate a signal (e.g., a baseband signal) including a PDU, an SDU, a message, control information, data or information according to the functions, procedures, proposals and / or methods disclosed in this document, and provide the signal to at least one transceiver (206). At least one processor (202) can receive a signal (e.g., a baseband signal) from at least one transceiver (206) and obtain the PDU, SDU, message, control information, data or information according to the descriptions, functions, procedures, proposals, methods and / or operational flowcharts disclosed in this document.

[0105] At least one processor (202) may be referred to as a controller, a microcontroller, a microprocessor, or a microcomputer. The at least one processor (202) may be implemented by hardware, firmware, software, or a combination thereof. For example, at least one application specific integrated circuit (ASIC), at least one digital signal processor (DSP), at least one digital signal processing device (DSPD), at least one programmable logic device (PLD), or at least one field programmable gate array (FPGA) may be included in the at least one processor (202). The descriptions, functions, procedures, proposals, methods, and / or operation flowcharts disclosed in this document may be implemented using firmware or software, and the firmware or software may be implemented to include modules, procedures, functions, etc. The descriptions, functions, procedures, proposals, methods, and / or operation flowcharts disclosed in this document may be included in the at least one processor (202), or may be stored in at least one memory (204) and driven by the at least one processor (202). The descriptions, functions, procedures, suggestions, methods and / or flowcharts disclosed in this document may be implemented using firmware or software in the form of code, instructions and / or sets of instructions.

[0106] At least one memory (204) can be connected to at least one processor (202) and can store various forms of data, signals, messages, information, programs, codes, instructions and / or commands. The at least one memory (204) can be configured as a read only memory (ROM), a random access memory (RAM), an erasable programmable read only memory (EPROM), a flash memory, a hard drive, a register, a cache memory, a computer readable storage medium and / or a combination thereof. The at least one memory (204) can be located internally and / or externally to the at least one processor (202). In addition, the at least one memory (204) can be connected to the at least one processor (202) via various technologies such as a wired or wireless connection.

[0107] At least one transceiver (206) can transmit user data, control information, wireless signals / channels, etc., mentioned in the methods and / or flowcharts of this document to at least one other device. At least one transceiver (206) can receive user data, control information, wireless signals / channels, etc. mentioned in the descriptions, functions, procedures, proposals, methods and / or flowcharts disclosed in this document from at least one other device. For example, at least one transceiver (206) can be connected to at least one processor (202) and can transmit and receive wireless signals. For example, at least one processor (202) can control at least one transceiver (206) to transmit user data, control information, or wireless signals to at least one other device. Furthermore, at least one processor (202) can control at least one transceiver (206) to receive user data, control information, or wireless signals from at least one other device. In addition, at least one transceiver (206) may be connected to at least one antenna (208), and at least one transceiver (206) may be configured to transmit and receive user data, control information, wireless signals / channels, etc. mentioned in the descriptions, functions, procedures, proposals, methods and / or operation flowcharts disclosed in this document through at least one antenna (208). In this document, at least one antenna may be a plurality of physical antennas or a plurality of logical antennas (e.g., antenna ports). At least one transceiver (206) may convert the received wireless signals / channels, etc. from RF band signals to baseband signals in order to process the received user data, control information, wireless signals / channels, etc. using at least one processor (202). At least one transceiver (206) may convert the processed user data, control information, wireless signals / channels, etc. from baseband signals to RF band signals using at least one processor (202).For this purpose, at least one transceiver (206) may include an (analog) oscillator and / or filter.

[0108] The components of the wireless device described with reference to FIG. 3 may be referred to by different terms in terms of functionality. For example, the processor (202) may be referred to as a control unit, the transceiver (206) as a communication unit, and the memory (204) as a storage unit. In some cases, the communication unit may be used to mean at least a portion of the processor (202) and the transceiver (206).

[0109] The structure of the wireless device described with reference to FIG. 3 can be understood as the structure of at least a portion of various devices. For example, the structure of the wireless device illustrated in FIG. 3 can be at least a portion of various devices described with reference to FIG. 2 (e.g., a robot (110a), a vehicle (110b-1, 110b-2), an XR device (110c), a portable device (110d), a home appliance (110e), an IoT device (110f), an AI device / server (110g)). Furthermore, according to various embodiments, in addition to the components illustrated in FIG. 3, the device may further include other components.

[0110] For example, the device may be a portable device such as a smartphone, a smart pad, a wearable device (e.g., a smart watch, smart glasses), or a portable computer (e.g., a laptop, etc.). In this case, the device may further include at least one of a power supply unit that supplies power and includes a wired / wireless charging circuit, a battery, etc., an interface unit that includes at least one port for connection with another device (e.g., an audio input / output port, a video input / output port), and an input / output unit for inputting and outputting image information / signals, audio information / signals, data, and / or information input from a user.

[0111] For example, the device may be a mobile device such as a mobile robot, a vehicle, a train, an aerial vehicle (AV), a ship, etc. In this case, the device may further include at least one of a driving unit including at least one of an engine, a motor, a power train, wheels, brakes, and a steering unit of the device, a power supply unit including a wired / wireless charging circuit, a battery, etc. that supplies power, a sensor unit that senses status information, environmental information, and user information of the device or its surroundings, an autonomous driving unit that performs functions such as path maintenance, speed control, and destination setting, and a position measurement unit that obtains location information of the mobile device through a global positioning system (GPS) and various sensors.

[0112] For example, the device may be an XR device such as an HMD, a head-up display (HUD) installed in a vehicle, a television, a smartphone, a computer, a wearable device, a home appliance, a digital signage, a vehicle, a robot, etc. In this case, the device may further include at least one of a power supply unit that supplies power and includes a wired / wireless charging circuit, a battery, etc., an input / output unit that obtains control information, data, etc. from the outside and outputs the generated XR object, and a sensor unit that senses status information, environmental information, and user information of the device or the surroundings of the device.

[0113] For example, the device may be a robot that can be classified into industrial, medical, household, military, etc. types depending on the purpose or field of use. In this case, the device may further include at least one of a sensor unit that senses status information, environmental information, and user information of the device or its surroundings, and a driving unit that performs various physical actions, such as moving the robot joints.

[0114] For example, the device may be an AI device such as a TV, a projector, a smartphone, a PC, a laptop, a digital broadcasting terminal, a tablet PC, a wearable device, a set-top box (STB), a radio, a washing machine, a refrigerator, digital signage, a robot, a vehicle, etc. In this case, the device may further include at least one of an input unit that acquires various types of data from the outside, an output unit that generates output related to sight, hearing, or touch, a sensor unit that senses status information, environmental information, and user information of the device or its surroundings, and a training unit that trains a model composed of an artificial neural network using learning data.

[0115] The structure of the wireless device illustrated in FIG. 3 may be understood as a part of a terminal (or first node), or as a part of an intermediate point, or as a part of a base station (or second node). If the device illustrated in FIG. 3 is a base station (or second node), the device may further include a wired transceiver for front haul and / or back haul communications. However, if the front haul and / or back haul communications are based on wireless communications, at least one transceiver (206) illustrated in FIG. 3 may be used for front haul and / or back haul communications, and a wired transceiver may not be included.

[0116] FIG. 4 illustrates a communication procedure between a first node (e.g., a terminal) and a second node (e.g., a base station) applicable to the present disclosure.

[0117] The second node of FIG. 4 supports dynamic spectrum sharing (DSS), which can provide connectivity to both nodes implementing 6G technology and nodes implementing pre-6G wireless communication technologies (e.g., 5G, 4G). That is, the first node of FIG. 4 can implement either 6G technology or pre-6G wireless communication technologies (e.g., 5G, 4G). Furthermore, the first node and / or the second node can support full duplex mode as well as non-overlapping full duplex mode.

[0118] In Fig. 4, for the sake of simplicity of explanation, the first node and the second node are assumed to be a terminal and a base station, respectively, and operations of the terminal (110) and the base station (120) transmitting and / or receiving data and operations performed prior thereto are illustrated. However, the operations of Fig. 4 are not limited to operations between the terminal and the base station, and may be interpreted as operations between the first node and the second node. In addition, although Fig. 4 illustrates direct wireless signal transmission and reception operations between the terminal (110) and the base station (120), one or more intermediate points may exist between the terminal (110) and the base station (120), and wireless signals may be transmitted and received via one or more intermediate points.

[0119] Referring to FIG. 4, the terminal (110) and the base station (120) can perform synchronization (401). For example, the terminal (110) performs an initial cell search operation. Specifically, the terminal (110) can detect a synchronization signal for connection to at least one base station transmitted from the base station (120) according to a predefined rule. Here, the synchronization signal can include a plurality of synchronization signals classified according to structure or purpose (e.g., a first synchronization signal (e.g., a primary synchronization signal), a second synchronization signal (e.g., a secondary synchronization signal), etc.). Through this, the terminal (110) can confirm the boundary of a unit (e.g., a frame, a subframe, a slot, and / or a symbol) constituting a wireless signal transmission of the base station (120) and obtain information (e.g., a cell identifier) ​​about the base station (120).

[0120] The terminal (110) can obtain system information transmitted from the base station (120) (403). The system information is information related to the properties, characteristics, and / or capabilities of the base station (120) required to access the base station (120) and use the service, and can be classified according to the content (e.g., whether it is essential for access), transmission structure (e.g., channel used, whether provided on-demand), etc., and can be classified into, for example, first system information (e.g., master information block (MIB), primary system information), second system information (e.g., system information block (SIB), secondary system information), etc. If necessary, the terminal (110) can transmit a signal requesting system information before receiving the system information. However, the request and provision of system information can be performed after the random access procedure described below.

[0121] The terminal (110) and the base station (120) can perform a random access procedure (405). The terminal (110) can transmit and / or receive at least one message (e.g., a random access preamble, a random access response (RAR) message, etc.) for the random access procedure based on information related to a channel for the random access procedure of the base station (120) obtained through system information (e.g., channel location, channel structure, structure of a supported preamble, etc.). For example, the terminal (110) can transmit a first message (e.g., a preamble, MSG1) through the channel for the random access procedure, receive a second message (e.g., an RAR message, MSG2), transmit a third message (e.g., MSG3) including information related to the terminal (110) (e.g., identification information) to the base station (120) using scheduling information included in the second message, and receive a fourth message (e.g., MSG4) for contention resolution and / or connection establishment. As another example, the first and third messages may be sent and received as one message, or the second and fourth messages may be sent and received as one message.

[0122] The terminal (110) and the base station (120) can perform signaling of control information (407). Here, the control information can be defined in various layers, such as a layer that controls a connection (e.g., a radio resource control (RRC) layer), a layer that handles mapping between logical channels and transport channels (e.g., a media access control (MAC) layer), and a layer that handles physical channels (e.g., a physical (PHY) layer). For example, the terminal (110) and the base station (120) can perform at least one of signaling for establishing a connection, signaling for determining settings related to communication, and signaling for indicating allocated resources.

[0123] The terminal (110) and the base station (120) can transmit and / or receive data (409). In other words, the terminal (110) and the base station (120) can process, transmit, and / or receive data based on signaling of control information. For example, when transmitting data, the terminal (110) or the base station (120) can perform at least one of channel encoding, rate matching, scrambling, constellation mapping, layer mapping, waveform modulation, antenna mapping, and resource mapping on the information bits. Conversely, when receiving data, the terminal (110) or the base station (120) can perform at least one of signal extraction from resources, waveform demodulation for each antenna, signal arrangement considering layer mapping, constellation demapping, descrambling, and channel decoding.

[0124] <6G System Core Technologies>

[0125] The 6G (wireless) system aims to provide (i) very high data rates per device, (ii) a very large number of connected devices, (iii) global connectivity, (iv) very low latency, (v) low energy consumption for battery-free Internet of Things (IoT) devices, (vi) ultra-reliable connectivity, and (vii) connected intelligence with machine learning capabilities. The vision of the 6G system can be divided into four aspects: intelligent connectivity, deep connectivity, holographic connectivity, and ubiquitous connectivity.

[0126] As core implementation technologies of the 6G system, technologies such as artificial intelligence (AI), THz (terahertz) communication, optical wireless technology, FSO backhaul network, massive MIMO technology, blockchain, 3D networking, quantum communication, unmanned aerial vehicles, cell-free communication, wireless information and energy transfer (WIET), integration of sensing and communication, integration of access backhaul networks, holographic beamforming, big data analysis, and large intelligent surface (LIS) can be adopted.

[0127] artificial intelligence

[0128] Incorporating AI into communications can streamline and improve real-time data transmission. AI can use numerous analytics to determine how complex target tasks should be performed. This means AI can increase efficiency and reduce processing delays. Time-consuming tasks such as handovers, network selection, and resource scheduling can be performed instantly using AI. AI can also play a crucial role in machine-to-machine (M2M), machine-to-human, and human-to-machine communications. Furthermore, AI can facilitate rapid communication in brain-computer interfaces (BCIs). AI-based communication systems can be supported by metamaterials, intelligent structures, intelligent networks, intelligent devices, intelligent cognitive radios, self-sustaining wireless networks, and machine learning.

[0129] The following describes a functional framework for AI / ML operations.

[0130] Below, to explain AI (or AI / ML) more specifically, the terms can be defined as follows.

[0131] - Data collection: Data collected from network nodes, management entities, or terminals as a basis for AI model training, data analysis, and inference.

[0132] - AI Model: A data-driven algorithm that applies AI technology to generate a set of outputs containing predictive information and / or decision parameters based on a set of inputs.

[0133] - AI / ML Training: An online or offline process of training an AI model by learning features and patterns that best represent the data and obtain a trained AI / ML model for inference.

[0134] - AI / ML Inference: The process of making predictions or inducing decisions based on collected data and the AI ​​model using a trained AI model.

[0135] Life Cycle Management (LCM) procedures for AI / ML models (i.e., model training, model deployment, model inference, model monitoring, model updates, etc.) can be divided into functionality-based LCM and model-based LCM. In functionality-based LCM, AI / ML models may not be identified by the network, and the network can direct the activation / deactivation / fallback / switching of AI / ML functionality. In model-ID (identifier)-based LCM, AI / ML models can be identified by the network, and the network / terminal can activate / deactivate / select / switch AI / ML models based on the model ID.

[0136] Figure 5 illustrates a general functional architecture for an AI / ML model.

[0137] In particular, Figure 5 illustrates a general functional architecture relevant to both Functionality-based LCM and Model-based LCM. Some of the functions or some of the data / information / command flows (i.e., arrows) illustrated in Figure 5 may be omitted.

[0138] Referring to FIG. 5, a general functional framework can be configured to include a data collection function (10), a model training function (20), a management function (30), an inference function (40), and a model storage function (50).

[0139] The Data Collection function (10) is a function that provides input data to the Model Training function (20), Management function (30), and Inference function (40). The Data Collection function (10) can perform data preparation based on raw data and provide input data processed through data preparation. Examples of raw data may include received data / measurement data from terminals or other network entities, inference / output of AI / ML models, etc. The Data Collection function (10) may be performed by a single entity (e.g., terminal, network node, etc.) or may be performed by multiple entities.

[0140] Here, training data (11) refers to data required as input for the AI / ML Model Training function (20). Monitoring data (12) refers to data required as input for the Management (30) of the AI / ML model or AI / ML function. Inference data (13) refers to data required as input for the AI / ML Inference function (30).

[0141] The Model Training function (20) is a function that performs AI / ML model training, validation, and testing, which can generate model performance metrics that can be used as part of the AI / ML model testing procedure. The Model Training function (20) can perform data preparation (e.g., data pre-processing and cleaning, forming, and transformation) based on the Training Data (11) transferred from the Data Collection function (10), if necessary.

[0142] Trained / Updated Model (21): If there is a Model Storage function (50), it is used to pass a trained, validated and tested AI / ML model to the Model Storage function (50) or to pass an updated version of the model to the Model Storage function (50).

[0143] The Management function (30) is a function that supervises the operation of the AI / ML model or AI / ML function. In addition, the Management function (30) may perform decisions to ensure appropriate inference operations based on data received from the Data Collection function (10) (i.e., Monitoring Data (12)) and / or data received from the Inference function (40) (i.e., Inference Output (41)).

[0144] Management Instruction (32) is information required as input to manage the Inference function (40). The relevant information may include selection / (de)activation / switching of an AI / ML model or AI / ML-based function, and may also include fallback to non-AI / ML operations (i.e., not relying on the inference process).

[0145] A Model Transfer / Delivery Request (33) can be used to request model(s) from Model Storage (50).

[0146] A Performance Feedback / Retraining Request (31) refers to information required as input to the Model Training function (20) (e.g., for the purpose of (re)training or updating the model).

[0147] The Inference function (40) is a function that provides output from the process of applying an AI / ML model or AI / ML function using data (i.e., Inference Data (13)) provided by Data Collection (10) as input. Data preparation (e.g., data preprocessing and cleaning, formatting, and transformation) may also be performed based on the Inference Data (13) delivered by Data Collection (10). If necessary, the Inference function (40) may also perform data preparation (e.g., data preprocessing and cleaning, forming, and transformation) based on the Inference Data (13) provided by Data Collection function (10).

[0148] Inference Output (41) is data used in the Management function (30) to monitor the performance of an AI / ML model or AI / ML function. Inference Output (41) may include the inference output of the AI / ML model generated by the Inference function (30), and the details of the inference output may vary depending on the use case.

[0149] The Model Storage function (50) stores a learned / updated model that can be used to perform the Inference function (40). The Model Storage function (50) illustrated in FIG. 5 can be used as a reference point (if any) when applicable to protocol termination, model transmission / delivery, and related processes. Furthermore, the Model Storage function (50) is merely an example and is not intended to limit the storage location of actual AI / ML models, and may be omitted.

[0150] Model Transfer / Delivery (51) is used to transfer AI / ML models to inference functions.

[0151] The level of cooperation can be defined as follows depending on the capability of AI / ML functions between multiple nodes, and variations due to combination of multiple levels or separation of any one level are also possible.

[0152] Cat 0a) No collaboration framework: AI / ML algorithms are purely implementation-based and do not require any changes to the wireless interface.

[0153] Cat 0b) This level corresponds to a framework with a modified wireless interface tailored to efficient implementation-based AI / ML algorithms, but without collaboration.

[0154] Category 1) involves inter-node support to improve the AI / ML algorithms of each node. For example, this applies when a specific node receives support from another node (for training, adaptation, etc.) and vice versa. At this level, model exchange between network nodes is not required.

[0155] Category 2) Joint AI / ML tasks can be performed across multiple nodes. This level requires the exchange of AI / ML model commands or network nodes.

[0156] FIG. 5 is a diagram illustrating an overall functional framework for an AI / ML model, and not all functions and / or all data / information / command signals illustrated in FIG. 5 may be performed within a specific node, but only some of them may be performed.

[0157] AI / ML models can be divided into one-side models and two-side models depending on whether training and / or inference are performed on a single node or jointly / sequentially on multiple nodes.

[0158] A one-side model can refer to an AI / ML model in which inference is performed entirely by a single node (e.g., a terminal or network). Here, AI / ML model training can also be performed entirely by a single node. AI / ML model training and inference can be performed by the same node, or they can be performed by separate nodes.

[0159] A two-side model can refer to an AI / ML model in which joint inference is performed across multiple nodes (e.g., terminals and networks). Joint inference refers to inference being performed jointly across multiple nodes. For example, the first part of the inference may be performed by a first node, and the remaining part by a second node. Two-side models can be categorized into several types depending on the training method of the AI / ML model, as follows:

[0160] - First type: AI / ML models can be trained on a single node. In this case, joint training can be performed. The trained model can then be distributed to other nodes / objects.

[0161] - Second type: Joint training of AI / ML models can be performed on multiple nodes / entities (e.g., networks and terminals). Joint training can mean that model generation (e.g., CSI generation part) and model reconstruction (CSI compression by sub-use case) are trained in the same loop for forward activation and backward gradient. In this type, joint training can include both simultaneous training (i.e., model generation training and model reconstruction training are performed simultaneously) and sequential training (i.e., model reconstruction training is performed after model generation training).

[0162] - Third type: Separate training of AI / ML models can be performed on multiple nodes (e.g., networks and terminals). Separate training may mean that training begins sequentially on one node and continues on other nodes. In this case, the first node first performs the AI / ML model and shares the training data with the second node. The second node can then use the shared training data to perform the AI / ML model. For example, training for the CSI generation part may be performed by the terminal, while CSI reconstruction may be performed by the network.

[0163] Figure 6 illustrates a communication procedure between a first node (e.g., terminal) and a second node (e.g., base station) to which an AI / ML model is applied.

[0164] The operations described below can be described / interpreted based on the AI / ML model proposed in this specification, as shown in Fig. 6 below, even without separate mention (i.e., without explicit mention of being by / based on / for the AI / ML model). In addition, unless specifically limited, the AI / ML model can correspond to a one-side model in which inference is entirely performed by a single node, or a two-side model in which joint inference is performed by multiple nodes.

[0165] First signaling (601): In the description below, the signaling (e.g., information / data / channel / signal, etc.) or set of signaling between a specific node (e.g., terminal, network, etc.) and another node may be interpreted as the signaling or set of signaling of the first signaling (601) used to perform an operation based on an AI / ML model, even if not otherwise mentioned. For example, it may correspond to training data for training (i.e., generation and / or reconstruction) the AI / ML model of FIG. 5, or correspond to inference data used for inference of the AI / ML model, or correspond to feedback for the AI / ML model, etc. If signaling between nodes is not required prior to an operation based on an AI / ML model in the present specification, the first signaling (601) may be omitted. If a one-side model is used in the present specification, the one-way / two-way signaling (set) in the present specification may correspond to the signaling of the first signaling (601). In addition, when a two-side model is used in this specification, the one-way / two-way signaling in this specification may correspond to the first signaling (601), and also, a repetitive signaling operation may correspond to the first signaling (601).

[0166] For example, in AI / ML model-based beam management (BM), if a base station predicts (i.e., infers) beam(s) with good quality based on an AI / ML model, the base station can receive quality / intensity information for multiple beams from a terminal. Furthermore, if a terminal predicts (i.e., infers) beam(s) with good quality based on an AI / ML model, the terminal can receive multiple beams from the base station.

[0167] AI / ML model-based operation (602): In the description below, an operation (e.g., calculation, selection, prediction, etc.) in a specific node (e.g., terminal, network, etc.) or a joint operation (e.g., calculation, selection, prediction, etc.) in multiple nodes (e.g., terminal, network, etc.) may correspond to an AI / ML model-based operation (602) based on one or more functions in the functional framework of the AI / ML model, even if not mentioned separately. For example, it may correspond to training (i.e., generation and / or reconstruction) of the AI / ML model of FIG. 5 or inference of the AI / ML model, etc. When a one-side model is used, an operation performed by a single node in the present specification may correspond to an AI / ML model-based operation (602), and also, when a two-side model is used, a joint operation performed by multiple nodes in the present specification may correspond to an AI / ML model-based operation (602).

[0168] For example, in an AI / ML model-based BM, the base station can use quality / intensity information for multiple beams received from the terminal as inference data to predict (i.e., infer) beam(s) with good quality based on the AI / ML model. Furthermore, the terminal can measure multiple beams received from the base station and use the measurement results as inference data to predict (i.e., infer) beam(s) with good quality based on the AI / ML model.

[0169] Second signaling (603): In the description below, signaling (e.g., information / data / channel / signal, etc.) or a set of signaling between a specific node (e.g., terminal, network, etc.) and another node may be interpreted as a second signaling (603) or a set of signaling generated due to (as a result of) an operation based on an AI / ML model, even if not otherwise mentioned. For example, it may correspond to an output resulting from inference of the AI / ML model in FIG. 5. If signaling between nodes is not required as a result of an operation based on an AI / ML model in this specification, the second signaling (603) may be omitted. If a one-side model is used in this specification, a one-way / two-way signaling (set) in this specification may correspond to the second signaling (603). In addition, when a two-side model is used in this specification, the one-way / two-way signaling in this specification may correspond to the second signaling (603), and also, a repetitive signaling operation may correspond to the second signaling (603).

[0170] For example, in an AI / ML model-based BM, the base station can transmit to the terminal the beam(s) predicted based on the AI / ML model as candidates so that the terminal can determine the optimal beam. Furthermore, the terminal can report to the base station the beam(s) predicted based on the AI / ML model to request the base station to transmit the candidate beams as candidates for determining the optimal beam.

[0171] THz communication (terahertz communication)

[0172] Data rates can be increased by increasing bandwidth. This can be achieved by utilizing sub-THz communications with wide bandwidths and applying advanced massive MIMO technology. THz waves, also known as sub-millimeter waves, typically refer to the frequency range between 0.1 THz and 10 THz, with corresponding wavelengths ranging from 0.03 mm to 3 mm. The 100 GHz to 300 GHz band (sub-THz band) is considered a key part of the THz spectrum for cellular communications. Adding the sub-THz band to the mmWave band will increase the capacity of 6G cellular communications. Among the defined THz bands, 300 GHz to 3 THz lies in the far infrared (IR) frequency band. While part of the optical band, the 300 GHz to 3 THz band lies at the boundary of the optical band, immediately following the RF band. Therefore, this 300 GHz to 3 THz band exhibits similarities to RF.

[0173] Figure 7 illustrates the electromagnetic spectrum according to one embodiment of the present disclosure. The embodiment of Figure 7 can be combined with various embodiments of the present disclosure. Key characteristics of THz communications include (i) a widely available bandwidth to support very high data rates, and (ii) high path loss at high frequencies (highly directional antennas are essential). The narrow beamwidth generated by the highly directional antenna reduces interference. The small wavelength of THz signals allows for a much larger number of antenna elements to be integrated into devices and base stations operating in this band. This enables the use of advanced adaptive array techniques to overcome range limitations.

[0174] Transmitting system information (i.e., information related to the properties, characteristics, and / or capabilities of a BS required to use a service, such as MIB, SIB, etc.) in the THz frequency band may be inefficient because, as the beam width becomes narrower in high frequency bands, more beam sweeps must be performed to cover the entire area of ​​the cell. In particular, transmitting system information in this manner is even more inefficient when there are not many users in the cell. Accordingly, a system information transmission procedure such as that illustrated in FIG. 8 may be used.

[0175] Figure 8 illustrates an example of a procedure for transmitting system information for THz communications to which the present disclosure applies. While this example was developed with THz in mind, it is also applicable to 6G communication environments where THz is not applicable. Furthermore, the procedure illustrated in Figure 8 can be combined with various embodiments of the present disclosure described below. For example, the embodiments described below can be performed based on system information acquired through the procedure illustrated in Figure 8.

[0176] Referring to FIG. 8, the base station can transmit system information of cell #1 through cell #2 (801). That is, the base station provides at least two cells, cell #1 uses a THz frequency band, and cell #2 uses a non-THz frequency band. Here, the system information can include at least one information / state / parameter / setting generated in each of a higher layer and a physical layer. For example, the at least one information / state / parameter / setting generated in the higher layer can include at least one of an SFN, control information setting for SIB1 (e.g., PDCCH configuration for SIB1, etc.), information related to cell selection / entry (e.g., cell barring, cell re-selection, etc.), and subcarrier spacing, and the at least one information / state / parameter / setting generated in the physical layer can include at least one of an SFN, a half frame indicator, and an SSB index. However, this is merely an example, and system information may include information / status / parameters / settings related to Cell #1 / Cell #2 generated from various types of physical layers / upper layers. For this purpose, as an example, Cell #1 and Cell #2 may have a relationship as a secondary cell and a primary cell.

[0177] The UE can acquire synchronization for cell #1 (803). Synchronization can be acquired by detecting a synchronization signal. Typically, synchronization is acquired before receiving system information. However, since the system information for cell #1 is received from cell #2, synchronization acquisition for cell #1 can be performed after receiving the system information. For example, the UE can acquire synchronization based on the system information. However, unlike FIG. 8, in another example, synchronization acquisition can be performed before step 801.

[0178] The UE may transmit a signal for accessing cell #1 (805). For example, the signal may include information for accessing cell #1 (e.g., a random access preamble). The structure of the signal and the resources for transmitting the signal (e.g., a channel) may be identified through system information. Thereafter, the UE and the base station may perform an access procedure for cell #1 and communicate (807). During this process, operations according to various embodiments described below may be performed.

[0179] The procedure described with reference to FIG. 8 may be performed when UE (801) first accesses cell #1 of the base station. Alternatively, a similar procedure may be performed when UE (801) hands over to cell #1 of the base station. However, in the case of handover, the system information of cell #1 may be received from a cell of a base station other than cell #2 of the base station.

[0180] Communications in the THz band are expected to experience extremely severe path loss, and to overcome this, terminals and base stations must use extremely sharp beams. The use of sharp beams means that terminals and base stations must perform beam control in addition to beamforming, and the number of beams used increases significantly. Consequently, it takes a very long time to align the transmit and receive beams between the base station and terminals. Furthermore, if the beam alignment between the base station and terminals is misaligned due to the movement or movement of the terminals, frequent re-alignment of the beams is required, which can lead to link instability. Accordingly, a beam management procedure, as illustrated in FIG. 9 below, may be employed.

[0181] FIG. 9 illustrates a beam management procedure applicable to the present disclosure. FIG. 9 illustrates an example of a procedure for searching and / or selecting beams for THz communication, but is not limited to a THz environment, and the present disclosure is applicable to a 6G communication environment. In addition, the procedure illustrated in FIG. 9 can be combined with various embodiments of the present disclosure described below. Here, a beam may be interpreted as 'spatial (setting) information', 'spatial domain filter', 'spatial domain transmission filter', 'spatial domain reception filter', or / and a term having an equivalent technical meaning that can distinguish the beam (e.g., Reference signal, SSB (Synchronization Signal Block) Index, TRP (transmission reception point), panel, cell, TP (transmission point), base station, control resource related information (e.g., CORESET (control resource set) related information, etc.).

[0182] Referring to FIG. 9, a base station can configure resources for beam management (901). Here, the resources can include at least one of time-frequency resources, channels, and spatial resources (e.g., antenna ports). For example, the base station can utilize a beam search signal (BSS) that is transmitted spatially separated from existing downlink signals / channels for beam search. Here, the BSS can be transmitted based on a dedicated port for beam search. The dedicated port can be a different port from a port for transmitting existing downlink signals / channels (e.g., synchronization signals (e.g., SSB, etc.), data channels (e.g., PDSCH, etc.)). BSS is a term defined for convenience of explanation, and the technical concept according to the present embodiment is not limited to the term BSS itself. That is, a signal transmitted based on a dedicated port defined / configured for beam search can be included in the technical concept according to the present embodiment.

[0183] The base station can transmit measurement signals using multiple transmission beams (903). For example, the measurement signals can include at least one of a reference signal and a synchronization signal. At this time, the measurement signals can be transmitted as many times as the number of beams that require measurement, and can be transmitted using a multi-beam transmission method that forms multiple beams simultaneously to reduce sweeping time. Here, the multi-beam transmission can be performed based on at least one of a multi-panel, a sub-array, and a true time delay (TTD).

[0184] The UE may transmit a feedback signal to the base station (905). The feedback signal indicates at least one beam selected by the UE. The UE may select at least one preferred beam based on the received measurement signals. The UE and the base station may communicate (907). At this time, the UE and the base station may communicate using the previously selected beam. If channel reciprocity is established, the transmission beam of the UE may also be determined through operations 903 and 905, and thus the transmission of the UE may also be performed using the beam selected in operation 905. If channel reciprocity is not established, a procedure including transmission of measurement signals by the UE and transmission of a feedback signal by the base station may be performed first to determine the transmission beam of the UE. In operation 907, operations according to various embodiments described below may be performed.

[0185] Integrated Sensing and Communication (ISAC)

[0186] Wireless sensing is a technology that uses radio frequencies to determine the instantaneous linear velocity, angle, distance (range), etc. of an object, thereby obtaining information about the characteristics of the environment and / or objects within the environment. Because radio frequency sensing does not require a networked device to connect to the object, it can provide a service for object positioning without a device. The ability to obtain range, velocity, and angle information from radio frequency signals can enable a wide range of new capabilities, such as various object detection, object recognition (e.g., vehicles, humans, animals, UAVs), and high-precision localization, tracking, and activity recognition. Wireless sensing services can provide information to a variety of industries (e.g., drones, smart homes, V2X, factories, railways, public safety, etc.), enabling applications such as intruder detection, assisted vehicle steering and navigation, trajectory tracking, collision avoidance, traffic management, and health and traffic management. In some cases, wireless sensing can utilize non-3GPP type sensors (e.g., radar, cameras) to further support 3GPP-based sensing. For example, the operation of wireless sensing services, i.e., sensing operations, may depend on the transmission, reflection, and scattering of wireless sensing signals. Therefore, wireless sensing offers an opportunity to enhance existing communication systems from a communication network to a wireless communication and sensing network.

[0187] FIG. 10 illustrates an example of a sensing operation according to an embodiment of the present disclosure. The embodiment of FIG. 10 can be combined with various embodiments of the present disclosure. Specifically, FIG. 10(a) illustrates an example of sensing using a sensing receiver and a sensing transmitter located at the same location (e.g., monostatic sensing), and FIG. 10(b) illustrates an example of sensing using a separated sensing receiver and sensing transmitter (e.g., bistatic sensing).

[0188] For example, in a wireless communication system based on a 6G network of the present specification, referring to FIG. 10(a), the sensing transmitter and the sensing receiver may be configured to be included in a single base station (i.e., the same base station) or a single terminal (i.e., the same terminal). Alternatively, referring to FIG. 10(b), the sensing transmitter and the sensing receiver may be configured to be included in different base stations, different terminals, or each terminal and base station.

[0189] In this regard, the following six types of sensing modes can be defined based on whether the sensing transmitter and sensing receiver are included in the base station or the terminal, respectively.

[0190] - Mode 1: A mode in which the sensing transmitter and sensing receiver are contained in a single base station (e.g., base station-based sensing mode in monostatic mode).

[0191] - Second mode: A mode in which the sensing transmitter is included in a first base station and the sensing receiver is included in a second base station different from the first base station (e.g., base station-based sensing mode in bistatic mode).

[0192] - Mode 3: A mode in which the sensing transmitter is included in the base station and the sensing receiver is included in the terminal (e.g., base station-terminal sensing mode).

[0193] - Mode 4: A mode in which the sensing transmitter is included in the terminal and the sensing receiver is included in the base station (e.g., terminal-base station sensing mode).

[0194] - Mode 5: A mode in which the sensing transmitter and sensing receiver are contained in a single terminal (e.g., terminal-based sensing mode in monostatic mode).

[0195] - 6th mode: A mode in which the sensing transmitter is included in a first terminal and the sensing receiver is included in a second terminal different from the first terminal (e.g., terminal-based sensing mode in bistatic mode).

[0196] In a wireless communication system based on a 6G network of the present specification, one or more of the six types of sensing modes described above may be utilized independently / in combination.

[0197] In relation to the sensing operation in FIG. 10, the sensing transmitter may transmit a sensing signal for sensing one or more objects (and / or an environment around the objects). For example, the sensing signal may correspond to a radio (frequency) signal defined to be transmittable by a base station / terminal in a wireless communication system based on a 6G network of the present specification. The sensing receiver may receive a signal scattered / reflected by one or more objects (and / or an environment around the objects) from a sensing signal transmitted from the sensing transmitter. In the sensing receiver, sensing data may be derived from the scattered / reflected signals, and sensing results may be generated / obtained through processing of the sensing data. Here, the sensing results may include characteristic information (e.g., location, distance, speed, angle, etc.) about one or more objects (and / or the environment around the objects). The sensing results generated / obtained in this way may be utilized for wireless sensing services (e.g., detection, tracking, etc. of objects and / or environments) provided in the wireless communication system based on the 6G network of the present specification, or may be provided / disclosed to a trusted third party.

[0198] Additionally, the sensing operation in FIG. 10 is described as a representative example of the operation in a wireless communication system based on a 6G network, but can be extended and applied to cases where terminals / base stations / signals based on networks of previous generations (e.g., 4G, 5G, etc.) are utilized.

[0199] Additionally, with respect to the wireless sensing described herein, in a wireless communication system based on a 6G network of the present specification, time / frequency resources for sensing operations and time / frequency resources for general communications (e.g., UL / DL / sidelink-based communications, etc.) may be scheduled / configured separately.

[0200] FIG. 11 illustrates time / frequency resources for sensing operations according to one embodiment of the present disclosure. The embodiment of FIG. 11 may be combined with various embodiments of the present disclosure.

[0201] Referring to FIG. 11, time / frequency resources (hereinafter, sensing resources) for the aforementioned sensing operation (e.g., sensing operation based on FIG. 10) can be set / allocated separately from time / frequency resources (hereinafter, communication resources) for general communication.

[0202] For example, as illustrated in FIG. 11, sensing resources can be set / allocated in units of symbols in the time domain and / or resource blocks in the frequency domain. Resources other than those for which the sensing resources are set / allocated can be utilized as resources for general communication. That is, sensing resources and communication resources can be set / allocated based on a time-division multiplexing (TDM) scheme and / or a frequency-division multiplexing (FDM) scheme in terms of the operation of the base station / terminal. Additionally or alternatively, unlike what is illustrated in FIG. 10, sensing resources can also be set / allocated based on other units in the time domain (e.g., slots, frames, absolute time (ms, us), etc.) and / or other units in the frequency domain (e.g., subcarriers, carriers, absolute frequencies (MHz, GHz), etc.).

[0203] Additionally or alternatively, in connection with the setting / allocation / scheduling of resources for general communication as described herein, the relationship between the resources and the aforementioned sensing resources may need to be considered. For example, when setting / allocating resources for general communication according to the embodiment(s) of the present disclosure, the resources may be set / allocated to rate-match or puncture the resource region corresponding to the sensing resource. For example, when scheduling resources for general communication according to the embodiment(s) of the present disclosure, the resources may be scheduled so as not to overlap with the resource region corresponding to the sensing resource. If the resources for general communication according to the embodiment(s) of the present disclosure and the resource region corresponding to the sensing resource are set / allocated / scheduled to overlap, one or both operations may be dropped, skipped, or postponed based on priorities, predefined rules, etc. That is, in the embodiment(s) of the present specification, it may be desirable that resources related to general communication (e.g., resources for signals / channels related to UL / DL / Sidelink-based data / control, etc.) are set / allocated / scheduled so as not to overlap with the sensing resources described above.

[0204] Additionally, various channel modeling methods may be applied in connection with the wireless sensing described herein. Channel modeling related to sensing may refer to configuring a path for transmitting and receiving sensing signals and / or scattered / reflected signals, taking into account the object being sensed and / or the environment in which the object resides. Channel modeling may be related to the performance / requirements of sensing in wireless communication systems, and thus may be an important factor in validating the sensing function.

[0205] Channels related to sensing can be divided into channels between objects (e.g., targets of interest) and sensing transmitters / receivers, and channels between the environment to which the object belongs and sensing transmitters / receivers. In this regard, channel modeling related to sensing can be divided based on sensing mode (e.g., the six types of modes described above), whether there is an object / environment, and / or sensing scenarios. For example, channel modeling for a target in a base station / terminal-based monostatic sensing mode, channel modeling for a target in a base station / terminal-based bistatic sensing mode, channel modeling for the environment in a base station / terminal-based monostatic sensing mode, and channel modeling for the environment in a base station / terminal-based bistatic sensing mode can be configured and optimized differently. For example, when various sensing scenarios are classified, channel modeling for detection, location, and tracking scenarios, channel modeling for motion recognition, and channel modeling for imaging / environment reconstruction scenarios can be divided, etc. Additionally, channel modeling related to sensing may be based on statistical channel modeling techniques and / or deterministic channel modeling techniques. For example, modeling for sensing in a wireless communication system based on a 6G network of the present disclosure may be based on stochastic geometric channel modeling techniques and / or hybrid with ray tracing channel modeling techniques. Here, the stochastic geometric channel model may be based on various statistical characteristics of the channel state. Furthermore, the hybrid channel model may be based on both ray tracing techniques and stochastic techniques.In a hybrid approach, channels for objects requiring high accuracy and consistency (e.g., targets of interest) can be modeled using ray tracing techniques, while channels for the environment can be modeled using probabilistic techniques.

[0206] FIG. 12 illustrates a procedure related to a sensing operation according to one embodiment of the present disclosure. The embodiment of FIG. 12 may be combined with various embodiments of the present disclosure.

[0207] For example, in a wireless communication system based on a 6G network of the present specification, in the case of a sensing operation in which a terminal participates, the base station may need to confirm (1205) the capability of the terminal for the sensing operation. In this regard, the terminal may be configured to report capability information on whether it supports the sensing operation to the base station. Additionally or alternatively, if the terminal is defined in advance in the standard as supporting the sensing operation, the procedure may be omitted. In addition, in the case of a sensing operation in which only the base station participates, the base station may be configured to report capability information on whether it supports the sensing operation to an entity that configures / controls its sensing operation (e.g., a network entity at an upper level / layer of the base station).

[0208] For example, the base station can perform signaling with the terminal to exchange configuration information related to the sensing operation. For example, the base station can set / instruct the terminal about the mode of the sensing operation (e.g., based on the six types of modes described above), the subject of the sensing operation (e.g., sensing transmitter, sensing receiver), the resource of the sensing operation (e.g., sensing resource as in FIG. 11), the target of utilizing the sensing result (e.g., type of wireless sensing service based on 6G network, trusted third party), channel modeling for sensing (e.g., channel between the base station / terminal and object / environment), etc. (1210). For example, the base station can also set / instruct such information from a network entity at an upper level / layer of the base station.

[0209] For example, the base station and / or the terminal may perform a sensing operation based on the set / instructed information (1215). For example, the base station and / or the terminal may, as a sensing transmitter and / or a sensing receiver, perform procedures such as transmitting a sensing signal, receiving a scattered / reflected signal, deriving sensing data, obtaining a sensing result through processing the sensing data, and providing the sensing result, as in FIG. 9 described above. As an example, in the operation of the base station / terminal described herein, the sensing result provided through the sensing operation may be utilized.

[0210] < Network Energy Saving, NES >

[0211] Network Energy Saving Technology of Rel-18

[0212] Energy conservation at base stations is a key consideration in wireless communication systems, including 3GPP, as it can contribute to building eco-friendly networks by reducing carbon emissions and reducing operational expenditures (OPEX) for telecommunications companies. In particular, the introduction of 5G communications will require higher transmission rates, necessitating base stations to be equipped with more antennas and provide services over wider bandwidths and frequency bands. Consequently, recent studies have shown that base station energy costs have reached as high as 20% of total OPEX. Accordingly, 5G systems are adopting various technologies to reduce energy consumption, known as network energy savings (NES), and the standardization of related technologies will continue.

[0213] Depending on the application of NES technology, the base station can perform operations such as controlling on / off for a certain duration in the time domain, controlling transmission / reception resources for UE-common or UE-specific signals / channels, changing the amount of frequency domain resources, controlling transmission power, or turning on / off antenna ports, transmission-reception points (TRPs), etc. in the spatial domain.

[0214] Figure 13 illustrates an example of the operation procedure of a base station supporting NES technology.

[0215] Referring to Figure 13, the base station can identify the NES solution(s) to be applied (1305). The NES solution(s) may be related to control of signal transmission and reception (e.g., on / off), beam operation, handover procedures, channel measurement and reporting, etc. The NES solution(s) to be applied may be adaptively selected or predefined based on the current situation (e.g., cell load level, characteristics of connected terminals, etc.). The base station that identified the NES solution(s) can perform signaling for the NES (1310). The specific signaling procedure may vary depending on the identified NES solution(s). For example, the base station may transmit common information about the NES solution(s), transmit configuration information necessary for NES operation to at least one terminal, or transmit control information regarding the progress of the NES operation to at least one terminal. In addition, the base station may receive capability information related to the NES from at least one terminal. Thereafter, the base station performs operations for the NES. At this time, the base station can perform operations for the NES based on the previously performed signaling (1315). That is, based on the system information, configuration information, and control information transmitted through the signaling, the base station can turn on / off the transmission and reception of specific signals, turn on / off elements in the spatial domain, or adjust resources for the transmission and reception of measurement signals.

[0216] Through a procedure similar to that in Fig. 13, NES technology can be implemented. Examples of NES solutions that can be implemented through a procedure similar to that in Fig. 13 are as follows.

[0217] - Intra-system energy saving solution: A RAN node can request a neighboring RAN node to switch at least one SSB beam into its inactive cell, or can perform paging using a limited set of beams to an inactive terminal (e.g., a stationary terminal).

[0218] - Inter-system energy saving solution: NG-RAN nodes that own capacity booster cells can autonomously transition those cells to an inactive state.

[0219] - SSB-less SCell solution: If SSB or SMTC (SSB-based RRM measurement timing configuration) configuration is not provided for the SCell, the UE can obtain timing reference and AGC source from another serving cell. In FR1 or FR2, the base station can configure intra-band CA or inter-band CA including the SCell without SSB transmission, in which case the SSB / SIB transmission can be triggered by the WUS (wake up signal) of the UE. Accordingly, since the period of common channels / signals such as SSB is increased, the base station can stay in the sleep state for a longer time.

[0220] - Cell DTX / DRX solution: In order to reduce the downlink transmission / uplink reception activity time of the base station, a periodic cell DTX / DRX pattern (e.g., active and inactive periods) can be commonly set for terminals within a cell having the corresponding feature. Here, the cell DTX pattern and the cell DRX pattern can be set and activated separately, and up to two cell DTX / DRX patterns can be set per MAC entity. When cell DTX is set and activated, at least one of monitoring for SPS opportunities or monitoring PDCCH can be stopped during the cell DTX inactivity period. When cell DRX is set and activated, at least one of transmission on CG resources or SR transmission can be stopped during the cell DRX inactivity period. Cell DTX / DRX can be activated / deactivated via RRC signaling or L1 group common signaling.

[0221] Parameters such as active duration and cycle may be configured for cell DTX / DRX. The active duration is the period during which the UE receives a PDCCH or SPS opportunity and waits to transmit SR or CG, and the cycle specifies the periodic repetition of the active duration and inactive duration. When both cell DTX and cell DRX are configured, parameters such as active duration and cycle are common. If the base station recognizes an emergency call or a public safety-related service (e.g., MPS or MCS), the network may release or deactivate the cell DTX / DRX configuration so as not to affect the service. In addition, at least some overlap is required between the active duration of the connected mode DRX of the UE and the active duration of the cell DTX / DRX. For example, the connected mode DRX cycle of the UE may be a multiple of the cell DTX / DRX cycle, or vice versa.

[0222] - Conditional handover (CHO) solution: A CHO procedure performed in a way that the execution of the handover is determined by the UE is used while the NES technology is applied (e.g., when the cell activates or deactivates cell DTX / DRX). In this case, the UE can use an NES-specific CHO event to initiate CHO for a candidate cell, and the reception of a DCI that activates the CHO condition(s) set by the NES event indication can be applied as an additional triggering condition for this.

[0223] - Spatial and power domain adaptation solution: To support the gNB for transceiver muting and / or transmit power adaptation, the UE may be configured to report multiple CSI entries in a CSI report based on multiple sub-configurations. Each sub-configuration corresponds to a spatial domain adaptation pattern (e.g., a subset of available spatial elements) and / or a power offset between a data channel (e.g., PDSCH) and CSI-RS. Depending on the application of the spatial and power domain adaptation solution, the CSI configuration, measurement, and / or reporting behavior may be affected.

[0224] Cell DTX / DRX

[0225] To operate a base station in sleep mode for a relatively long period of time without frequent wake-ups, a base station DTX / DRX has been proposed for NES purposes. The base station can reduce energy consumption by utilizing DTX transmission in low system load situations by setting a cell DTX and setting the on-duration of the C-DRX of terminals within the active period of the cell DTX. Figure 14 illustrates an example of a procedure for cell DTX / DRX operation.

[0226] Referring to FIG. 14, the base station transmits system information to the terminal (1401), and the terminal checks information related to cell DTX / DRX (1402). For example, the system information may include MIB, SIB1, etc. In relation to NES technology, the MIB may include information related to cell barring (e.g., cellBarred), and the SIB1 may include information related to the cell barring status (e.g., cellBarredNES). Specifically, if cellBarred included in the MIB is set to a value indicating that it is not barred (e.g., notBarred), the terminal may determine that the cell is not barred, regardless of whether it supports NES cell DTX / DRX. Conversely, if cellBarred included in the received MIB is set to a value indicating that the cell is barred (e.g., barred), a terminal that does not support NES cell DTX / DRX may determine that the cell is barred. However, if the terminal has the capability to support NES cell DTX / DRX, the terminal checks SIB1 to determine the cell barring status. If cellBarred of MIB is set to barred and cellBarredNES is absent in SIB1, the terminal supporting NES cell DTX / DRX can treat the cell as barred and perform cell reselection to another cell. On the other hand, if cellBarred of MIB is set to barred and cellBarredNES is included in SIB1, the terminal supporting NES cell DTX / DRX can determine that the cell is not barred.

[0227] In the case of FIG. 14, it is assumed that the terminal has the capability to support NES cell DTX / DRX, and the cellBarred of the MIB is set to notBarred, or the cellBarred of the MIB is barred and cellBarredNES is included in SIB1. Accordingly, the terminal performs a random access procedure to connect to the base station (1403), and can perform communication thereafter. At this time, the base station performs a cell DTX / DRX operation and transmits configuration information related to the cell DTX / DRX operation to the terminal (1404). The configuration information related to the cell DTX / DRX operation (e.g., CellDTXDRX-Config) includes at least one parameter related to the cell DTX / DRX, and may include, for example, at least one of an on-duration timer, a cycle start offset, a slot offset, a configuration type (e.g., DTX, DRX, or DTX-DRX), and an activation state of the DTX / DRX (e.g., active, inactive). Additionally, the configuration information may further include information for receiving and interpreting cell DRX / DRX-related control information (e.g., DCI-related information).

[0228] Thereafter, the base station transmits control information related to cell DTX / DRX to the terminal (1405). The control information related to cell DTX / DRX may include DCI having a designated format (e.g., format 2_9). If an operation for a serving cell according to at least one of the cell DTX operation and the cell DRX operation is configured by configuration information (e.g., cellDTXDRX-Config), the terminal may check a set of search spaces (e.g., a set of Type3-PDCCH CSS) for monitoring a PDCCH conveying control information of a designated format during an active time through a higher layer parameter (e.g., SearchSpace), and may obtain a location of information about the serving cell within the control information through a higher layer parameter (e.g., positionInDCI-cellDTRX). Then, the terminal may obtain control information based on the identified set of search spaces and location.

[0229] Control information related to cell DTX / DRX may be used to indicate activation or deactivation of cell DTX and / or cell DRX, and / or to provide an NES-mode indicator, and may include, for example, at least one block including a cell DTX / DRX indicator and an NES-mode indicator. In this case, when the serving cell is configured as a SUL (supplementary uplink) carrier, the indication of activation or deactivation of cell DRX by the cell DTX / DRX indicator may be applied to both the UL carrier and the SUL carrier.

[0230] Thereafter, the terminal and the base station can perform communication based on the cell DTX / DRX (1406). Specifically, the base station can turn on / off the transmission and reception of signals according to the settings related to the cell DTX / DRX, and accordingly, the terminal can selectively monitor the signal from the base station. During the DTX-OFF, the base station enters a sleep mode to reduce energy consumption. At this time, the base station DTX cycle can be aligned with the cycle of the terminal DRX. The base station DTX-ON can completely cover the DRX-ON of the terminal. Furthermore, the base station can align the transmission of Xn / NG and the transmission of Uu for the purpose of NES. The DTX / DRX mechanism triggers the switching of reference signal resource set groups, and the base station can perform a dormancy-like behavior of sparsely transmitting or not transmitting SSB, SIB, and CSI-RS to reduce energy consumption. The terminal can sparsely receive or not receive a downlink signal / channel depending on the settings of the base station. Once the base station DTX / DRX operation is triggered, during the DTX / DRX OFF period, the terminal can discontinuously receive the corresponding CSI-RS, SSB, or PDCCH.

[0231] SSB-less SCell

[0232] Figure 15 illustrates an example of a procedure for CA operation using SSB-less SCell.

[0233] Referring to FIG. 15, the base station transmits configuration information for the SCell to the terminal. That is, the base station transmits configuration information for CA to provide a service to the terminal through CA operation. Here, the CA operation may be intra-band CA or inter-band CA. For example, the configuration information for the SCell may include information including information for adding the SCell (e.g., sCellToAddModList), and specifically, may include a cell index, a physical cell identifier, information related to DL-UL configuration, information related to BWP, information related to cell DTX / DRX, information related to downlink frequency (e.g., FrequencyInfoDL), etc. Then, the terminal can determine the configuration for the CA operation and perform communication using the PCell and SCell of the base station. At this time, the terminal can confirm that the SCell is an SSB-less SCell based on the information related to the downlink frequency included in the configuration information, and check the related parameters. For example, a terminal can determine that an SCell is an SSB-less SCell by checking for the presence of a parameter indicating that it is an SSB-less SCell (e.g., SSBlessSCell), and can determine the timing reference and AGC source for the SCell based on information about the reference cell (e.g., referenceCell). In the case of Fig. 15, the reference cell may be a PCell. Therefore, the terminal can use the PCell as a timing reference and AGC source for communication on the SCell.

[0234] Conditional Hand Over (CHO)

[0235] Figure 16 illustrates an example of a Conditional Handover (CHO) procedure. The order of the operations illustrated in Figure 16 may vary depending on the case.

[0236] Referring to FIG. 16, the base station transmits configuration information for CHO to the terminal (1601). The configuration information for CHO may include information related to conditional reconfiguration (e.g., ConditionalReconfiguration, CondReconfigToAddModList) and information related to configuration for reporting (e.g., ReportConfigNR). Here, the information related to configuration for reporting may include information related to events related to reporting, identifiers of the events (e.g., condEventId), information indicating whether it is an NES-specific CHO event (e.g., nesEvent), etc. In the example of FIG. 16, event information indicating that it is an NES-specific CHO event is received.

[0237] The base station transmits information for enabling an NES-specific CHO execution condition to the terminal (1602). The information for enabling the NES-specific CHO execution condition may be transmitted via control information of a specified format (e.g., DCI format 2_9). The information for enabling the NES-specific CHO execution condition may be referred to as an NES-mode indicator, for example, as 1-bit information, which indicates enabling the NES-specific CHO execution condition when a related upper layer parameter (e.g., nesEvent) is set and the serving cell of the related block in the corresponding DCI is a primary cell.

[0238] Thereafter, the terminal performs a measurement (1603) and transmits a measurement report to the base station (1604). The base station determines a CHO based on the measurement report and performs signaling for a handover request with the neighboring base stations indicated by the measurement report (1606). The base station determines the neighboring base stations that have confirmed admission through signaling as candidate base stations and transmits information about the candidate base stations to the terminal (1607). Accordingly, the terminal evaluates the CHO execution conditions for the candidate base stations (1608). Accordingly, when a candidate cell satisfying the condition is determined, the terminal detaches from the old cell and synchronizes to the new cell (1609). At this time, since the terminal has previously received event information indicating that it is a NES-specific CHO event and also received information enabling the NES-specific CHO execution condition, it can determine whether the event is satisfied. In other words, if a NES-mode indicator is received through a lower layer and conditional triggering configuration information (e.g., condTriggerConfig) includes information (e.g., nesEvent) indicating that the event is a NES-specific CHO event, the terminal can determine that the event associated with the corresponding measurement identifier (e.g., measId) is satisfied, and thus determine that the CHO execution condition is satisfied.

[0239] NES Enhancement

[0240] 3GPP NR release 19 will discuss NES enhancements, with (1) On-demand SSB, (2) On-demand SIB1 transmission, and (3) adaptation of common signal / channel transmissions being considered as key targets.

[0241] (1) On-demand SSB

[0242] A method to reduce energy consumption by having a base station transmit SSB on a specific cell through an on-demand SSB process and not transmit SSB on that cell when an on-demand SSB process is not available can be discussed. In the existing NR system, SSB must be transmitted periodically and constantly for purposes such as time / frequency synchronization or RRM measurement, making it difficult to reduce energy consumption even when the base station has no data to receive or send. Considering this, the base station can reduce base station energy consumption by not performing SSB transmission until the on-demand SSB process is involved and then performing SSB transmission. The on-demand SSB process can be triggered using one of the following methods:

[0243] 1) The terminal requests SSB transmission from the base station by transmitting an uplink signal / channel (e.g., PRACH, PUCCH, PUSCH, SRS in the NR system).

[0244] 2) Requesting SSB transmission from base station (or TRP) #1 to base station (or TRP) #2 through an interface between base stations (e.g., Xn interface in NR system) or backhaul signaling.

[0245] 3) Signaling whether SSB transmission is possible for the corresponding Scell ​​through Scell ​​activation / deactivation signaling.

[0246] Considering coexistence with existing NR terminals, Release 19 is limited to on-demand SSB operation for connected mode terminals and SCells. However, in future releases or next-generation communication systems, on-demand SSB operation (for SSB transmission on PCell) considering inactive or idle mode terminals or initially connected terminals may be defined. In addition, carrier aggregation (CA) including the SCell can be applied to both intra-band CA and inter-band CA, and the SSB on the SCell transmitted through the on-demand SSB process can be utilized for at least functionality such as time / frequency synchronization, L1 / L3 measurement, and SCell activation.

[0247] (2) On-demand SIB1 transmission

[0248] A method to reduce energy consumption by having the base station transmit SIB1 for a specific cell through the on-demand SIB1 process and not transmit SIB1 for the cell when there is no on-demand SIB1 process can be discussed. In the existing NR system, SIB1 containing system information, random access information, etc. for initial access or idle mode terminals to access a cell had to be provided periodically, so it was difficult to reduce energy consumption even when the base station had no data to receive or send. Considering this, the base station can reduce base station energy consumption by not performing SIB1 transmission until the on-demand SIB1 process is accompanied and then performing SIB1 transmission. The on-demand SIB1 process can trigger the base station's SIB1 transmission by the terminal transmitting an uplink signal / channel (e.g., PRACH in the NR system). Specifically, the following scenarios can be considered but may not be limited to the following scenarios.

[0249] 1) Scenario 1: As in (a) of Fig. 17, when a UE receives an SSB (and / or other downlink signal / channel) from a cell#1 and recognizes that SIB1 is not transmitted on the cell#1, the UE can trigger SIB1 transmission by transmitting a signal requesting SIB1 (for convenience, the signal is referred to as a WUS (wake-up signal)) based on information provided in the SSB (and / or other downlink signal / channel) and / or predetermined information. The base station that receives the WUS can transmit a specific DL signal / channel on cell#1 in response thereto, and (or) transmit SIB1 on cell#1 (without transmitting the DL signal / channel).

[0250] 2) Scenario 2: As in (b) of Fig. 17, a terminal may attempt to camp on cell#2 when it receives an SSB (and / or other downlink signal / channel such as SIB1) from a cell#1 and recognizes that SIB1 is not transmitted on the corresponding cell#2. The terminal may trigger SIB1 transmission for cell#2 by transmitting a signal requesting SIB1 (i.e., WUS) on cell#1 based on information provided in the received SSB (and / or other downlink signal / channel such as SIB1) and / or predetermined information. The base station receiving the WUS may transmit a specific DL signal / channel (on cell#1 or cell#2) in response thereto, and may transmit SIB1 for cell#2 on cell#1 or cell#2 (or without transmitting the DL signal / channel).

[0251] 3) Scenario 3: As in (c) of Fig. 17, a terminal that receives an SSB (and / or other downlink signal / channel such as SIB1) from a cell#1 and recognizes that SIB1 is not transmitted on the corresponding cell#2 may attempt to camp on cell#2. The terminal may trigger SIB1 transmission for cell#2 by transmitting a signal requesting SIB1 (i.e., WUS) on cell#2 based on information provided in the received SSB (and / or other downlink signal / channel such as SIB1) and / or predetermined information. The base station that receives the WUS may transmit a specific DL signal / channel (on cell#1 or cell#2) in response thereto, and may transmit SIB1 for cell#2 on cell#1 or cell#2 (or without transmitting the DL signal / channel).

[0252] (3) adaptation of common signal / channel transmissions

[0253] Methods for reducing energy consumption by modulating the transmission of common signals / channels such as SSB, PRACH, and paging by the base station can be discussed. While completely disabling SSB can significantly reduce the energy consumption of the base station, the absence of SSB, which performs functions such as time / frequency synchronization and RRM measurement, may not guarantee stable operation for the corresponding cell from the UE's perspective. Considering this, energy savings at the base station can be achieved by varying the SSB transmission pattern (e.g., transmission period, period per SSB candidate index(es), SSB candidate index(es) transmitted within a transmission period, transmission power, etc.) depending on the situation.

[0254] In the case of PRACH resources, since the base station cannot know when the terminal will transmit the PRACH in the case of contention-based random access, energy consumption may increase because the base station always attempts to receive within the configured PRACH resources. Considering this, energy of the base station can be saved by applying a method to adjust the amount of PRACH resources (e.g., adjusting the period of PRACH resources, adjusting the amount of resources through instructions such as pre-configuring PRACH resource set #1 and set #2 and turning on only one set or both sets, or providing the corresponding RACH resource amount uniformly or non-uniformly for each SSB index).

[0255] In the case of paging, previously, paging frames (PF) and / or paging occasions (PO) were distributed along the time axis within a DRX cycle (or paging cycle), and the terminal attempted to receive paging at a specific PF / PO derived from its ID-based formula. From the base station's perspective, if paging was to be transmitted to multiple terminals simultaneously, it may have to wake up frequently to transmit paging. To reduce base station energy consumption due to this, it is possible to consider arranging PFs and / or POs for paging reception as close to the time axis as possible or arranging different frequency resources within the same time.

[0256] Figure 18 illustrates an example of SSB transmission of a base station operating multiple frequency bands.

[0257] From the perspective of a base station operating multiple frequency bands, even when the number of terminals served is small or the traffic load is relatively low, the amount of energy consumed by periodically sending SSB and / or system information can be large.

[0258] Referring to FIG. 18, from the perspective of a base station operating three frequency bands (in the present invention, the frequency bands can be replaced with bands, carriers, serving cells, BWPs, etc.), energy can be saved by periodically transmitting (legacy) SSBs only in some frequency bands (e.g., F1), transmitting simplified (or modified) S-SSBs (simplified SSBs) in the remaining frequency bands (e.g., F2), or not transmitting SSBs in other frequency bands (e.g., F3). In the case of a terminal operating in F2 or F3, the terminal can request SSB transmission from the base station in the corresponding frequency band, or the base station can adaptively resume / adjust SSB transmission according to its own judgment. The SSB transmitted in this way is conveniently named on-demand SSB, and the SSB can be a legacy SSB or a simplified (or modified) S-SSB (simplified SSB). Here, a cell where SSB is not transmitted, such as F2 or F3, or where the SSB transmission cycle can be adaptively controlled, can be conveniently named an SSB-less cell, and can be a PCell / PSCell / SCell from the terminal's perspective. In addition, a ref-cell refers to a cell linked for timing sync and / or AGC (automatic gain control) setting and / or UL power control (or path-loss estimation) and / or beam management-related measurement (e.g., L1-RSRP / L1-SINR, etc.) and / or RRM measurement (e.g., RSRP, RSRQ, RSSI, etc.) of an SSB-less cell, and can be a cell other than an SSB-less cell (e.g., PCell / PSCell / SCell / non-serving cell, etc.).

[0259] For example, when SSB request by a terminal is supported, the base station can configure to the terminal which of the following uplink signals / channels to utilize to request on-demand SSB, and the terminal can request on-demand SSB through a specific uplink signal / channel based on the configuration from the base station. For convenience, the uplink signal / channel transmitted by the terminal for the purpose of requesting on-demand SSB is named UL_SSB (or WUS).

[0260] - PRACH: A separate RO (RACH occasion) can be set up for on-demand SSB purposes, or some PPRACH preamble index(es) within a specific RO can be set up for on-demand SSB purposes.

[0261] - Scheduling request PUCCH / PRACH: When transmitting SR (PUCCH / PRACH) corresponding to an SSB-less cell, the UE may be considered to always request on-demand SSB. Alternatively, SR resources for requesting on-demand SSB may be configured separately (from SR resources that do not request on-demand SSB). SR resources may refer to separate time / frequency resources and / or sequence resources.

[0262] - SRS: A separate SRS resource may be set up for requesting on-demand SSB. The SRS resource may refer to a separate time / frequency resource and / or sequence resource.

[0263] - PUCCH: On-demand SSB request information can be carried periodically or aperiodically through periodic or semi-persistent PUCCH.

[0264] - PUSCH: On-demand SSB request information can be carried periodically or aperiodically through PUSCH scheduled through UL grant or semi-persistent PUSCH (e.g., configured grant PUSCH or semi-persistent CSI-reporting on PUSCH, etc.).

[0265] - The above UL_SSB resource may be set on an SSB-less cell or may be set on a cell other than the SSB-less cell (e.g., PCell / PSCell / SCell / non-serving cell, etc.).

[0266] A terminal may be configured with one or more UL_SSB resources, and may select different UL_SSB resources according to the following conditions. Here, different UL_SSB resources may mean different time / frequency / sequence resources for the same uplink signal / channel, different types of uplink signals / channels, or different cells corresponding to the UL_SSB resources.

[0267] - Setting different UL_SSB resources by SSB index (group): Here, the SSB index may mean an index corresponding to an SSB to be transmitted on an SSB-less cell, or may mean an index corresponding to an SSB to be transmitted on a ref-cell. The ref-cell means a cell for which interworking is set for timing sync and / or AGC (automatic gain control) setting and / or UL power control (or path-loss estimation) and / or beam management-related measurement (e.g., L1-RSRP / L1-SINR, etc.) and / or RRM measurement (e.g., RSRP, RSRQ, RSSI, etc.) of the SSB-less cell, and may be a cell other than an SSB-less cell (e.g., PCell / PSCell / SCell / non-serving cell, etc.). For example, different UL_SSB resources may be configured for each SSB index (or SSB index group) corresponding to the SSB to be transmitted on the SSB-less cell (or the SSB to be transmitted on the ref-cell), and UL_SSB resource #1 corresponding to SSB (group) index #0 and UL_SSB resource #2 corresponding to SSB (group) index #1 may be configured in advance. If the UE wishes to request SSB (group) index #1, it may transmit UL_SSB resource #2. Specifically, in preparation for cases where it is not clear whether the UE requests a specific SSB (group) index, a separate UL_SSB resource may be configured for requesting all SSB indexes, and in that case, the UE may request transmission for all SSB indices by performing uplink transmission through the corresponding UL_SSB resource.

[0268] - Configure different UL_SSB resources according to the transmission duration and / or periodicity and / or SSB pattern of the SSB that the terminal requests: The transmission duration may refer to the period from when on-demand SSB starts to when it ends on an SSB-less cell. For example, when on-demand SSB is transmitted P times with a cycle of X msec from slot #n on an SSB-less cell, and SSB is no longer transmitted and may be turned off from slot #n+k, the k slots (or the absolute time corresponding to k slots or P) may be defined as the duration. The SSB periodicity may refer to the (minimum) transmission time interval between identical SSB (candidate) indexes. In addition, when multiple SSB patterns (e.g., legacy SSB and simplified SSB) are pre-configured / defined, different UL_SSB resources may be configured for each SSB pattern. For example, when UL_SSB resource #1 corresponding to SSB transmission duration #1 and UL_SSB resource #2 corresponding to SSB transmission duration #2 are separately set, the terminal can perform uplink transmission by selecting UL_SSB resource #2 according to the required SSB transmission duration, and it can be assumed that on-demand SSB can be transmitted during SSB transmission duration #2.

[0269] - When there is more than one ref-cell corresponding to an SSB-less cell, different (or identical) UL_SSB resources are set for each ref-cell: When multiple ref-cells are set to correspond to a specific SSB-less cell, different UL_SSB resources can be set for each ref-cell. For example, when a PCell and another SCell are set as ref-cells for an SSB-less cell, UL_SSB resource #1 with the PCell as the ref-cell and UL_SSB resource #2 with the other SCell as the ref-cell can be set, and when a UE requests an SSB linked to the PCell on the SSB-less cell, uplink transmission can be performed through UL_SSB resource #1.

[0270] - When UL_SSB resources corresponding to one or more SSB-less cells are configured for a common cell, different UL-SSB resources are configured for each SSB-less cell (or group of SSB-less cells): For example, in a situation where a UE carrier aggregates three serving cells, both SCell#0 and SCell#1 operate as SSB-less cells, and the UL_SSB resource for requesting SSB on SCell#0 and the UL_SSB resource for requesting SSB on SCell#1 can both be configured on the PCell. In this case, Opt-1) the UL_SSB resource for requesting SSB on SCell#0 and the UL_SSB resource for requesting SSB on SCell#1 may be configured identically, or Opt-2) the UL_SSB resource for requesting SSB on SCell#0 and the UL_SSB resource for requesting SSB on SCell#1 may be configured differently. For Opt-1, the UE can request on-demand SSB for both SCells by performing uplink transmission through the common UL_SSB resource, and for Opt-2, the UE can request on-demand SSB for a specific SCell by performing uplink transmission on one of the different UL_SSB resources.

[0271] - Different UL_SSB resources are set depending on whether the SSB requested by the UE is NCD-SSB (non-cell defining-SSB) or CD-SSB (cell defining-SSB): NCD-SSB may mean that CORESET index 0 and type0-PDCCH CSS set information are not included through PBCH information in the SSB, and CD-SSB may mean that CORESET index 0 and type0-PDCCH CSS set information are included through PBCH information in the SSB. UL_SSB resource #1 corresponding to NCD-SSB and UL_SSB resource #2 corresponding to CD-SSB may be set separately, and if the UE performs uplink transmission through UL_SSB resource #1 (or resource #2), the UE may expect that NCD-SSB (or CD-SSB) may be transmitted in the corresponding SSB-less cell.

[0272] Additionally, the terminal may perform an on-demand SSB request by utilizing UL_SSB resources when certain conditions are satisfied, which may be cases where one or more of the following conditions are satisfied.

[0273] - When a terminal has UL data to transmit or DL ​​data to receive through an SSB-less cell: Specifically, when UL data is generated and SR is transmitted, an on-demand SSB request can be performed simultaneously with the SR resource, or an on-demand request can be performed using a separate UL_SSB resource after SR transmission.

[0274] - When receiving DL through an SSB-less cell, if it is determined that the reception timing (or DL ​​RX synchronization) is out of sync by a certain threshold (e.g., X ns or Y time samples) or the transmission and reception success probability (for initial transmission) is below a certain threshold: The threshold value used for determination may be a value defined in advance in the specifications or set by the base station.

[0275] - When the sensitivity of the signal received through the SSB-less cell and / or ref-cell satisfies a specific condition: The signal received through the SSB-less cell and / or ref-cell may be the SSB index and / or CSI-RS resource transmitted on the ref-cell, or may be the CSI-RS transmitted on the SSB-less cell. And, the type of signal may be defined in advance or set by the base station. Specifically, it may be a signal set / indicated as a reference signal for QCL / TCI / spatial relation information of a certain DL / UL signal / channel received or transmitted on the SSB-less cell. The sensitivity of such a signal may mean the result value of the L1 and / or L3 measurement (e.g., beam management related measurement such as L1-RSRP, L1-SINR and / or RRM measurement such as RSRP, RSRQ, RSSI, etc.) corresponding to the signal. A specific condition can be defined as being satisfied when the reception sensitivity decreases below / below a certain threshold value (event#1), when the change in reception sensitivity is above / exceeds a certain threshold value (event#2), or when such events (event#1 and / or event#2) occur more than a certain threshold number of times. The threshold value can be defined in advance or can be a value set by the base station. In addition, when counting the number of times an event has occurred, it can be counted how many times the event has occurred within a certain (sliding) time window (the time window value can be defined in advance or can be set by the base station).At this time, if an event occurs again within a certain duration (the duration value can be defined in advance or set by the base station) from the time of event occurrence, the count value can be increased, and if not, the count value can be reset.

[0276] Configuration for Cell supporting on-demand SSB

[0277] Below, we propose a specific signaling method for setting up an SSB-less cell, terminal operations that can assist the base station in determining the ref-cell, and conditions for triggering on-demand SSB.

[0278] In the following description, on-demand SSB may mean an SSB that the base station starts transmitting upon a request from the terminal, or may mean an SSB that the base station starts transmitting upon its own judgment without a request from the terminal. For example, unlike conventional SSBs that are always transmitted according to a fixed cycle (e.g., always on SSB), an SSB in which the transmission and frequency of SSB can be adaptively adjusted according to the base station's judgment and / or the terminal's request is referred to as on-demand SSB (or simply OD-SSB).

[0279] For convenience, the embodiments are described using the term SSB-less Cell defined in the current NR standard. However, the SSB-less Cell in the proposed embodiments is not limited to a cell in which SSB transmission off is supported, and is used as a concept encompassing various cells (e.g., Pcell, PScell, Scell, non-serving cell) in which adaptive OD SSB transmission (e.g., on / off, period control, and / or Simplified SSB) is supported. SSB adaptation in such an SSB-less Cell may be performed based on the judgment of the base station itself (without a separate UE request) or based on a request from a UE (or another network node / base station). The SSB-less Cell is not limited to an Scell, and depending on the embodiment, a Pcell may also be used as an SSB-less Cell (adaptive SSB transmission in a Pcell).

[0280] The proposals described below may be implemented independently or as a combination of multiple proposals.

[0281] Proposal 1. Signaling for establishing SSB-less cells

[0282] First, we will examine SSB less cells in existing NR systems with reference to Tables 1 and 2. As previously explained, the SSB less cells in the embodiments proposed in this specification are not limited to the concept of existing SSB less cells defined in Tables 1 and 2.

[0283] FrequencyInfoDL information element-- ASN1START-- TAG-FREQUENCYINFODL-STARTFrequencyInfoDL ::= SEQUENCE {absoluteFrequencySSBARFCN-ValueNR OPTIONAL, -- Cond SpCellAddfrequencyBandList MultiFrequencyBandListNR,absoluteFrequencyPointA ARFCN-ValueNR,scs-SpecificCarrierList SEQUENCE (SIZE (1..maxSCSs)) OF SCS-SpecificCarrier,...,[[referenceCell-r18ServCellIndex OPTIONAL -- Cond SSBlessSCell]]}-- TAG-FREQUENCYINFODL-STOP-- ASN1STOPField descriptionabsoluteFrequencySSBThe frequency of the SSB to be used for the serving cell. The SSB-related parameters (e.g., SSB index) provided to the serving cell refer to the SSB frequency unless otherwise stated. The CD (cell defining)-SSB of the PCell is always in the synchronization raster. Frequencies are considered to be in the synchronization raster if they can also be identified by their GSCN values ​​(see TS 38.101-1

[0015] or TS 38.101-5

[0075] ). If this field is absent, SSB related parameters (e.g. ssb-PositionsInBurst, ssb-periodicityServingCell and subcarrierSpacing in the ServingCellConfigCommon IE) are not provided. If this field is absent, the UE acquires the timing reference from the SpCell or SCell as described in TS 38.213

[0013] , section 4.1, or from the SpCell or SCell specified by referenceCell, or from the "default cell".This is supported when the SCell from which the UE obtains its timing reference is in the same or different frequency band than the cell from which the UE obtains its timing reference (i.e., SpCell or SCell, respectively). (e) For cells supporting RedCap, this field corresponds to CD-SSB. [Frequency of the SSB to be used for this serving cell. SSB related parameters (e.g., SSB index) provided for a serving cell refer to this SSB frequency unless mentioned otherwise. The CD-SSB of the PCell is always on the sync raster. Frequencies are considered to be on the sync raster if they are also identifiable with a GSCN value (see TS 38.101-1

[0015] or TS 38.101-5

[0075] ). If the field is absent, the SSB related parameters should be absent, eg ssb-PositionsInBurst, ssb-periodicityServingCell and subcarrierSpacing in ServingCellConfigCommon IE. If the field is absent, the UE obtains timing reference from the SpCell or an SCell if applicable as described in TS 38.213

[0013] , clause 4.1, or from the SpCell or an SCell indicated by referenceCell, or from the "default cell" defined in TS [xx].This is supported in case of the SCell for which the UE obtains the timing reference in the same or different frequency band as the cell (i.e. the SpCell or the SCell, respectively) from which the UE obtains the timing reference. For cells supporting (e)RedCap, this field corresponds to the CD-SSB.]referenceCell Indicates the reference cell, i.e. the cell that provides the timing reference and AGC (auto gain control) source for the SSB-less SCell. If the reference cell is an SCell or PSCell, it should be an activated SCell or activated PSCell. If this field is absent, a "default cell" is the reference cell. [Indicates the reference cell, i.e. the cell that provides the timing reference and AGC source for the SSB-less SCell. If the reference cell is an SCell or PSCell, it should be an activated SCell or activated PSCell. If this field is absent, a "default cell" is the reference cell as defined in TS [xx]].

[0284] - SSB-MTCSSB-MTC는 측정 타이밍 설정들 (단말이 SSB들을 측정하는 타이밍 기회들)을 설정한는데 사용된다[The IE SSB-MTC is used to configure measurement timing configurations, i.e., timing occasions at which the UE measures SSBs.]SSB-MTC information element-- ASN1START-- TAG-SSB-MTC-STARTSSB-MTC ::= SEQUENCE {periodicityAndOffset CHOICE {sf5 INTEGER (0..4),sf10 INTEGER (0..9),sf20 INTEGER (0..19),sf40 INTEGER (0..39),sf80 INTEGER (0..79),sf160 INTEGER (0..159)},duration ENUMERATED { sf1, sf2, sf3, sf4, sf5}}SSB-MTC2 ::= SEQUENCE {pci-List SEQUENCE (SIZE (1..maxNrofPCIsPerSMTC)) OF PhysCellId OPTIONAL, -- Need Mperiodicity ENUMERATED {sf5, sf10, sf20, sf40, sf80, spare3, spare2, spare1}}SSB-MTC2-LP-r16 ::= SEQUENCE {pci-List SEQUENCE (SIZE (1..maxNrofPCIsPerSMTC)) OF PhysCellId OPTIONAL, -- Need Rperiodicity ENUMERATED {sf10, sf20, sf40, sf80, sf160, spare3, spare2, spare1}}SSB-MTC3-r16 ::= SEQUENCE {periodicityAndOffset-r16 CHOICE {sf5-r16 INTEGER (0..4),sf10-r16 INTEGER (0..9),sf20-r16 INTEGER (0..19),sf40-r16 INTEGER (0..39),sf80-r16 INTEGER (0..79),sf160-r16 INTEGER (0..159),sf320-r16 INTEGER (0..319),sf640-r16 INTEGER (0..639),sf1280-r16 INTEGER (0..1279)},duration-r16 ENUMERATED {sf1, sf2, sf3, sf4, sf5},pci-List-r16 SEQUENCE (SIZE (1..maxNrofPCIsPerSMTC)) OF PhysCellId OPTIONAL, -- Need Mssb-ToMeasure-r16 SetupRelease { SSB-ToMeasure} OPTIONAL -- Need M}SSB-MTC4-r17 ::= SEQUENCE {pci-List-r17 SEQUENCE (SIZE (1..maxNrofPCIsPerSMTC)) OF PhysCellId OPTIONAL, -- Need Moffset-r17 INTEGER (0..159)}SSB-MTC-AdditionalPCI-r17 ::= SEQUENCE {additionalPCIIndex-r17 AdditionalPCIIndex-r17,additionalPCI-r17 PhysCellId,periodicity-r17 ENUMERATED { ms5, ms10, ms20, ms40, ms80, ms160, spare2, spare1},ssb-PositionsInBurst-r17 CHOICE {shortBitmap BIT STRING (SIZE (4)),mediumBitmap BIT STRING (SIZE (8)),longBitmap BIT STRING (SIZE (64))},ss-PBCH-BlockPower-r17 INTEGER (-60..50)}AdditionalPCIIndex-r17 ::= INTEGER(1..maxNrofAdditionalPCI-r17).

[0285] In the existing NR system, if there is a cell in which the SSB configuration (i.e., the absoluteFrequencySSB parameter of the FrequencyInfoDL IE in Table 1) is not set and the SMTC (SSB measurement timing configuration) configuration (i.e., the SSB-MTC IE in Table 2) is not provided, the terminal regards the cell as an SSB-less cell.

[0286] Specifically, as shown in Table 1, the frequency position at which the SSB to be used for the corresponding serving cell is transmitted is signaled through the absoluteFrequencySSB parameter. However, if the absoluteFrequencySSB parameter is absent, the SSB-related parameters (e.g., ssb-PositionsInBurst, ssb-periodicityServingCell and subcarrierSpacing in ServingCellConfigCommon IE) for the corresponding serving cell may also be absent. In addition, if the absoluteFrequencySSB parameter is absent, the timing reference cell (or the target cell for obtaining time / frequency synchronization and / or AGC gain) for the corresponding serving cell may be determined by one of the following rules.

[0287] - Decision method #1: Determined as either PCell, PSCell, or SCell without separate signaling (in the case of SCell, the conditions of belonging to the same TAG as the serving cell and belonging to the same cell group may be satisfied)

[0288] - Decision method #2: PCell or PSCell or SCell set as timing reference cell by separate parameter (e.g., referenceCell)

[0289] The above decision method #1 can be applied to a situation where there is intra-band CA between an SSB-less cell and a timing reference cell, and decision method #2 can be applied to a situation where there is inter-band CA between an SSB-less cell and a timing reference cell. In addition, in 2), if no separate parameter is set, the default cell for the timing reference cell can be determined by a separate rule or determined to follow decision method #1.

[0290] However, even in the case of an SSB-less cell, if SSB can be transmitted on the cell through an on-demand SSB process, SSB-related parameters and / or SMTC configuration-related parameters may be required, so the existing signaling structure may not be able to efficiently support the on-demand SSB process on the SSB-less cell.

[0291] Therefore, in this specification, we propose a method for setting up an SSB-less cell to efficiently perform an on-demand SSB process.

[0292] (1) Alt 1

[0293] For example, both absoluteFrequencySSB parameters (including SSB-related parameters such as ssb-PositionsInBurst, ssb-periodicityServingCell and subcarrierSpacing in ServingCellConfigCommon IE) and SMTC configuration can be provided for the corresponding SSB-less cell. Regardless of whether OD SSB is (actually) transmitted in the corresponding SSB-less cell, the configuration information required for OD SSB reception can be provided to the UE through at least one cell that is identical to or different from the corresponding SSB-less cell, taking into account the potential possibility of OD SSB transmission in the SSB-less cell.

[0294] A separate parameter (e.g., ssb-less-cell) is used to set that the serving cell is an SSB-less cell and / or a separate parameter (e.g., referenceCell) is used to set the PCell or PSCell or SCell as a timing reference cell for the serving cell: For example, if the separate parameter (e.g., ssb-less-cell) is enabled for the serving cell (even if the absoluteFrequencySSB parameter, SSB-related parameters, SMTC settings, etc. are provided), the UE can recognize that the serving cell is an SSB-less cell. As another example, if another serving cell is set as a timing reference cell for the serving cell through the separate parameter (e.g., referenceCell) (even if the absoluteFrequencySSB parameter, SSB-related parameters, SMTC settings, etc. are provided), the UE can recognize that the serving cell is an SSB-less cell. If the serving cell itself is set as a timing reference cell through the above separate parameter (e.g., referenceCell) for the serving cell, the terminal can recognize that the serving cell is not an SSB-less cell. Here, recognizing that it is an SSB-less cell means ignoring the provided information such as the absoluteFrequencySSB parameter, SSB-related parameters, and SMTC settings, and recognizing that it is not an SSB-less cell may mean applying the provided information such as the absoluteFrequencySSB parameter, SSB-related parameters, and SMTC settings.

[0295] The terminal can recognize that on-demand SSB is transmitted on the corresponding SSB-less cell by transmitting a UL_SSB signal and receiving a response to the signal.

[0296] Alternatively, the terminal may recognize that on-demand SSB is transmitted on the SSB-less cell by receiving separate signaling from the base station (e.g., SCell activation RRC or MAC-CE, or separate RRC or MAC-CE or DCI, etc.). In the existing NR standard, i) one way of Scell ​​configuration is to set the Scell ​​to a deactivation state through RRC signaling, and then activate the Scell ​​through signaling of Scell ​​activation / deactivation MAC CE, and ii) another way of simultaneous activation and configuration of the Scell ​​through RRC signaling is supported. According to an example of the present disclosure, ii) an RRC IE that performs Scell ​​(i.e., SSB-less cell) configuration and activation together may be used to notify the terminal that OD SSB transmission on the Scell ​​(i.e., SSB-less cell) will be performed, or an RRC IE may be newly defined to notify that OD SSB transmission will be performed separately from this. Alternatively, for example, a MAC CE that controls whether to perform OD SSB transmission on an Scell ​​(i.e., SSB-less cell) / transmission cycle, etc., may be provided to the terminal.

[0297] When the terminal recognizes that on-demand SSB is transmitted, the terminal may attempt to receive SSB on the SSB-less cell by applying the provided information, such as the absoluteFrequencySSB parameter, SSB-related parameters, and SMTC settings that are preset on the SSB-less cell. The separate parameter (e.g., ssb-less-cell) may be considered to be disabled for the serving cell. If another serving cell is set as a timing reference cell for the serving cell through the separate parameter (e.g., referenceCell), the terminal may ignore the setting or may consider the serving cell itself to be set as the timing reference cell.

[0298] Conversely, the terminal can recognize that no SSB is transmitted on the SSB-less cell by transmitting a UL_SSB signal and not receiving a response to that signal.

[0299] Alternatively, the UE may recognize that SSB is not transmitted on the SSB-less cell by receiving separate signaling from the base station (e.g., SCell activation RRC or MAC-CE, or separate RRC or MAC-CE or DCI, etc.). For example, the base station may explicitly inform the UE that OD SSB transmission on the Scell ​​(i.e., SSB-less cell) will not be performed (anymore) through signaling such as RRC IE or MAC CE. Alternatively, the UE may implicitly recognize that OD SSB transmission will not be performed by not providing signaling such as RRC IE or MAC CE indicating that OD SSB transmission on the Scell ​​(i.e., SSB-less cell) will be performed.

[0300] In this case, the terminal can ignore the provided information such as the absoluteFrequencySSB parameter, SSB-related parameters, and SMTC settings preset on the SSB-less cell. The terminal may not attempt to detect OD SSB on the SSB-less cell using the preset parameters. At this time, it may be considered that the separate parameter (e.g., ssb-less-cell) is enabled for the serving cell. If another serving cell is configured as a timing reference cell for the serving cell through the separate parameter (e.g., referenceCell), the terminal may perform time / frequency synchronization by applying the separate parameter (e.g., referenceCell) information. Alternatively, (if another serving cell is not configured as a timing reference cell for the serving cell through the separate parameter (e.g., referenceCell)) the same method as the above-described determination method #1 may be applied, or the timing reference cell may be directly signaled through a signal / channel (or a separate downlink signal / channel) notifying that SSB is not transmitted on the SSB-less cell. At this time, the terminal can perform time / frequency synchronization by applying the timing reference cell determined by the above decision method #1 or the timing reference cell information signaled separately.

[0301] (2) Alt 2

[0302] For example, both absoluteFrequencySSB parameters (including SSB-related parameters such as ssb-PositionsInBurst, ssb-periodicityServingCell and subcarrierSpacing in ServingCellConfigCommon IE) and SMTC settings may not be provided for the SSB-less cell as before.

[0303] The UE can recognize that on-demand SSB is transmitted on the SSB-less cell by transmitting a UL_SSB signal and receiving a response to the signal or by receiving separate signaling (e.g., SCell activation RRC or MAC-CE, or separate RRC or MAC-CE or DCI, etc.) from the base station. At this time, the absoluteFrequencySSB parameter (including SSB-related parameters such as ssb-PositionsInBurst, ssb-periodicityServingCell and subcarrierSpacing in ServingCellConfigCommon IE) and SMTC configuration information may be provided by the signal / channel notifying that on-demand SSB is transmitted and / or a separate signal / channel transmitted by the base station, and the UE can attempt to receive SSB on the SSB-less cell by applying the information. If another serving cell is configured as a timing reference cell for the serving cell through the separate parameter (e.g., referenceCell), the UE can ignore the configuration information.

[0304] (3) Alt 3

[0305] On-demand SSB configuration such as SSB index information to be transmitted for on-demand SSB (e.g., ssb-PositionsInBurst), periodicity information (e.g., ssb-periodicityServingCell), sub-carrier-spacing information (e.g., subcarrierSpacing), and / or SSB frequency information (e.g., absoluteFrequencySSB) can be set, and some or all of the configuration information can be set as separate parameters (from the SSB configuration transmitted on the ref-cell or the always-on SSB configuration transmitted on the corresponding cell), or can be set as the same parameter or a specific value determined by a rule. For convenience, the SSB that is always periodically transmitted for the corresponding cell is called always-on SSB.

[0306] If there is always-on SSB for that cell, absoluteFrequencySSB parameters (including SSB-related parameters such as ssb-PositionsInBurst, ssb-periodicityServingCell and subcarrierSpacing in ServingCellConfigCommon IE) and SMTC configuration can be provided for that cell, and in addition to that always-on SSB, on-demand SSB configuration can be provided.

[0307] - The UE can recognize that on-demand SSB is transmitted on the SSB-less cell by transmitting a UL_SSB signal and receiving a response to the signal or by receiving separate signaling (e.g., SCell activation RRC or MAC-CE, or separate RRC or MAC-CE or DCI, etc.) from the base station. In this case, the UE can attempt to receive on-demand SSB by applying information preset by the on-demand SSB configuration on the cell.

[0308] - Conversely, the UE may recognize that SSB is not transmitted on the SSB-less cell by transmitting a UL_SSB signal and not receiving a response to the signal or by receiving separate signaling from the base station (e.g., SCell activation RRC or MAC-CE, or separate RRC or MAC-CE or DCI, etc.). In this case, the UE may not attempt to receive on-demand SSB on the cell.

[0309] If there is no always-on SSB for the cell, the absoluteFrequencySSB parameter (including SSB-related parameters such as ssb-PositionsInBurst, ssb-periodicityServingCell, and subcarrierSpacing in ServingCellConfigCommon IE) and SMTC configuration may not be provided for the cell. Instead, an on-demand SSB configuration may be provided. In this case, the cases with and without a ref-cell may need to be supported.

[0310] - Case 1 (If there is no linked ref-cell SSB): If there is no cell in an intra-band CA relationship with the corresponding cell or there is no ref-cell set through the separate parameter (e.g., referenceCell), the terminal can recognize that there is no ref-cell linked to the corresponding cell. Alternatively, the base station can signal whether there is a ref-cell linked to the corresponding cell or not through a separate parameter, and the terminal that receives the signaling that there is no ref-cell linked through the parameter can recognize that there is no ref-cell linked to the corresponding cell. If there is no ref-cell linked to the corresponding cell, it may mean that the terminal can only utilize on-demand SSB when performing SCell activation and measurement for the corresponding cell.

[0311] - Case 2 (If there is a linked ref-cell SSB): If there is at least one cell that has an intra-band CA relationship with the corresponding cell or if there is a ref-cell configured through a separate parameter (e.g., referenceCell), the terminal can recognize that there is a ref-cell linked to the corresponding cell. Alternatively, the base station can signal whether there is a ref-cell linked to the corresponding cell through a separate parameter, and the terminal that receives the signaling that there is a linked ref-cell through the parameter can recognize that there is a ref-cell linked to the corresponding cell. If there is a ref-cell linked to the corresponding cell, it may mean that the terminal can utilize on-demand SSB and / or ref-cell SSB when performing SCell activation and measurement for the corresponding cell.

[0312] For the above Case 1 and / or Case 2, the UE can recognize that on-demand SSB is transmitted on the SSB-less cell by transmitting a UL_SSB signal and receiving a response to the signal or by receiving separate signaling (e.g., SCell activation RRC or MAC-CE or separate RRC or MAC-CE or DCI, etc.) from the base station. In this case, the UE can attempt to receive on-demand SSB by applying information preset by the on-demand SSB configuration on the cell.

[0313] Conversely, for Case 1 and / or Case 2, the UE may recognize that SSB is not transmitted on the SSB-less cell by transmitting a UL_SSB signal and not receiving a response to the signal or by receiving separate signaling (e.g., SCell activation RRC or MAC-CE or separate RRC or MAC-CE or DCI, etc.) from the base station. In this case, the UE may not attempt to receive on-demand SSB on the cell.

[0314] For the above Alt 1 and / or Alt 2, cases where there is a ref-cell and cases where there is no ref-cell may also need to be supported. Specifically, for the above Alt 1 and / or Alt 2, as in Case 1, if there is no cell in an intra-band CA relationship with the corresponding cell or there is no ref-cell configured through the separate parameter (e.g., referenceCell), the terminal can recognize that there is no ref-cell linked to the corresponding cell. Alternatively, the base station may signal whether there is a ref-cell linked to the corresponding cell or not through a separate parameter, and the terminal that receives signaling through the parameter that there is no ref-cell linked to the corresponding cell can recognize that there is no ref-cell linked to the corresponding cell. In addition, for the above Alt 1 and / or Alt 2, as in Case 2, if there is at least one cell in an intra-band CA relationship with the corresponding cell or there is a ref-cell configured through the separate parameter (e.g., referenceCell), the terminal can recognize that there is a ref-cell linked to the corresponding cell. Alternatively, the base station may signal whether or not there is a ref-cell linked to the cell through a separate parameter, and a terminal that receives signaling that there is a ref-cell linked through the parameter may recognize that there is a ref-cell linked to the cell.

[0315] According to the current NR standard document (Section 7 of TS 38.213), the UE performs path-loss estimation based on the difference between the SSB or CSI-RS transmission power value and the RSRP value that passed L3 filtering, and determines the uplink transmission power value based on the estimated value. However, it may be difficult for the UE to perform path-loss estimation in a cell where SSB is not transmitted, such as in an SSB-less cell. Considering this, when the base station configures the SSB-less cell, it can provide a delta value based on a specific cell to assist in path-loss estimation for the SSB-less cell. Specifically, when configuring an SSB-less cell, if a delta value for path-loss estimation is additionally provided, the terminal can derive a path-loss estimation value for the SSB-less cell by applying the delta to the path-loss estimation result value measured based on a specific cell (a PCell or PSCell within the same cell group or a specific SCell with the lowest / highest serving cell index can be set by a rule or can be set separately). For example, PL in the formula of Section 7.1.1 of NR specification TS 38.213 b,f,c (q d ) determines the value for a specific serving cell c, and when the serving cell index of the SSB-less cell is c' and the delta value is given, the path-loss estimation value PL for the SSB-less cell b,f,c (q d ) is PL b,f,c (q d )+delta (or PL b,f,c (q d)-delta) can be calculated.

[0316] Proposal #2. UE's assistance information for determining reference cells

[0317] When the base station does not transmit SSB on cell#A, the base station needs to inform the UE communicating in that cell#A of the SSB being transmitted on another cell#B (i.e., ref-cell) for the purpose of time / frequency synchronization and / or performing AGC (automatic gain control). However, depending on the UE implementation, some UEs may be able to apply the time / frequency synchronization acquired through SSB from cell#B to cell#A, while others may not. Alternatively, depending on factors other than the UE implementation, such as the UE's location / mobility, whether or not the UE utilizes SSB from cell#B may vary.

[0318] In case a UE cannot apply the time / frequency synchronization acquired through SSB from Cell#B to cell#A, it can request SSB transmission on cell#A to the base station through the on-demand SSB process. However, this mechanism may cause unnecessary delay during the SCell activation process, so it may be helpful for the UE to inform the base station in advance of the reference cell for cell#A it prefers. Therefore, the present invention proposes a method for efficiently operating the on-demand SSB process by having the UE report to the base station information on a cell that it prefers or that appears feasible as the reference cell of an SSB-less SCell.

[0319] First, the base station can set / instruct the terminal to a candidate serving cell list that can become the ref-cell for cell#A.

[0320] A terminal that has received a candidate serving cell list can feed back cell information satisfying one or more of the following criteria to the base station.

[0321] - Time / frequency synchronization obtained through SSB on a specific cell in the candidate serving cell list can be applied to cell#A.

[0322] - When the difference between the downlink reception timing from the SSB and / or downlink signal on a specific cell belonging to the candidate serving cell list and the downlink reception timing from the (SSB and / or) downlink signal on cell#A is less than or equal to a specific value (the value may be defined in advance or set / indicated).

[0323] - When the difference between the downlink reception quality (e.g., RSRP, RSRQ, etc.) from the SSB and / or downlink signal on a specific cell belonging to the candidate serving cell list and the downlink reception quality (e.g., RSRP, RSRQ, etc.) from the (SSB and / or) downlink signal on cell#A is less than or equal to a specific value (the value may be defined in advance or set / indicated).

[0324] - When the downlink reception quality (e.g., RSRP, RSRQ, etc.) from the SSB and / or downlink signal on a specific cell belonging to the candidate serving cell list is higher than a specific value (the value can be defined in advance or set / indicated).

[0325] The terminal can report cell index information satisfying the condition(s) as in the above example to the base station. The cell index information may be a single cell index information selected by the terminal, and one or more cell index information may be reported according to the configuration from the base station or terminal selection. In addition, the reception timing (difference) value and / or reception quality (difference) value may be reported together with the reported cell index(es). The reported contents may be carried on the PUSCH (or PUCCH) in the form of MAC-CE, and may be carried on the PUSCH or PUCCH in the form of UCI such as HARQ-ACK or CSI or SR, and reported by the terminal to the base station. If the reported cell index information is NULL or identical to cell#A, the base station can interpret it as the terminal requesting SSB transmission on the corresponding cell#A. In other words, the terminal can request SSB transmission on the corresponding cell#A by filling the reported cell index information with NULL or configuring it identical to cell#A.

[0326] Proposal #3. Trigger conditions for terminal on-demand SSB requests

[0327] A terminal may perform an on-demand SSB request by utilizing UL_SSB resources when certain conditions are satisfied, and one or more of the following conditions may be satisfied.

[0328] (1) When UL data to be transmitted or DL ​​data to be received by the terminal is generated through an SSB-less cell: Specifically, when UL data is generated and SR is transmitted, an on-demand SSB request can be performed simultaneously with the SR resource, or an on-demand request can be performed using a separate UL_SSB resource after SR transmission.

[0329] (2) When it is determined that the reception timing (or DL ​​RX synchronization) is out of sync with a certain threshold (e.g., X ns or Y time samples) when receiving DL through an SSB-less cell (compared to the reception timing when receiving DL such as SSB through a ref-cell) or the transmission and reception success probability (for initial transmission) is below a certain threshold: The threshold value used for the determination may be a value defined in advance in the specifications or set by the base station.

[0330] (3) When the sensitivity of the signal received through the SSB-less cell and / or ref-cell satisfies a specific condition: The signal received through the SSB-less cell and / or ref-cell may be the SSB index and / or CSI-RS resource transmitted on the ref-cell, or may be the CSI-RS transmitted on the SSB-less cell. And, the signal may be defined in advance or set by the base station. Specifically, it may be a signal set / indicated as a reference signal of QCL / TCI / spatial relation information of a certain DL / UL signal / channel received or transmitted on the SSB-less cell. The sensitivity of such a signal may mean the result value of L1 and / or L3 measurement (e.g., beam management related measurement such as L1-RSRP, L1-SINR and / or RRM measurement such as RSRP, RSRQ, RSSI, etc.) corresponding to the signal. A specific condition can be defined as being satisfied when the reception sensitivity decreases below / below a certain threshold value (event#1), the difference between the reception sensitivity from the SSB-less cell and the reception sensitivity from the ref-cell becomes greater than / below a threshold value (event#2), the change in reception sensitivity becomes greater than / exceeds a certain threshold value (event#3), or when such events (event#1 and / or event#2 and / or event#3) occur more than a certain threshold number of times. The threshold value may be defined in advance or may be a value set by the base station.Additionally, when counting the number of times an event has occurred, it is possible to count how many times the event has occurred within a sliding time window (the time window value can be defined in advance or set by the base station). At this time, if the event occurs again within a certain duration (the duration value can be defined in advance or set by the base station) from the time the event occurred, the count value can be increased, and if not, the count value can be reset.

[0331] (4) When the time / frequency synchronization acquired through reception of SSB (and / or CSI-RS) from the ref-cell cannot be applied to the SSB-less cell: Depending on the terminal implementation, some terminals may be able to apply the time / frequency synchronization acquired through SSB (and / or CSI-RS) from the ref-cell to the SSB-less cell, while other terminals may not. Alternatively, whether or not the terminal utilizes SSB from the ref-cell may vary depending on factors such as the location / mobility of the terminal rather than the terminal implementation. When the terminal cannot apply the time / frequency synchronization acquired through SSB (and / or CSI-RS) from the ref-cell to the SSB-less cell, the terminal may trigger the on-demand SSB process.

[0332] (5) When the Ref-cell becomes deactivated state, transitions to dormant BWP, or becomes NES state / mode: The state of the SCell can be changed to deactivated state by RRC or MAC-CE, etc., and SSB may not be transmitted on the deactivated SCell. Dormantancy of a specific serving cell can be indicated through DCI (e.g., DCI format 2_6 or DCI formats that can schedule DL / UL data), and transitions to dormant BWP when certain conditions are met or through BWP switching indication / configuration, and SSB may not be transmitted on the dormant BWP. The base station can notify that SSB will no longer be transmitted on a specific cell by notifying that the state / mode of a specific cell is NES state / mode, and the UE receiving the signaling can know that SSB will not be transmitted on the cell as the cell has become NES state / mode. In case SSB is not transmitted on a specific cell determined as a ref-cell in this way, another ref-cell is determined through at least one of the following methods, and the terminal can receive SSB from the ref-cell.

[0333] - Opt A) A specific ref-cell is determined by a pre-defined rule: For example, if serving cell index #A, B, C are set as candidates in advance as ref-cells, and SSB is not transmitted on the ref-cell as in the above case, the serving cell with the highest priority (e.g., serving cell #A) can be determined as the new ref-cell by a set priority (the priority can be set in advance, the serving cell with the lowest or highest cell index can have a higher priority, or the priority can be determined in the order of candidate ref-cell setting). Alternatively, when SSB is not transmitted on the ref-cell as in the above case, a specific cell (e.g., PCell or PSCell) within the same cell group can be determined as the new ref-cell by a rule. Alternatively, when SSB is not transmitted on the ref-cell as in the above case, the UE can assume that SSB will be transmitted on an SSB-less cell.

[0334] - Opt B) Different ref-cell is determined by separate signaling: When there is a downlink signal / channel indicating / setting deactivation and / or dormancy and / or NES state / mode as described above, a new ref-cell can be signaled (e.g., serving cell index for the new ref-cell) via that downlink signal / channel or a separate downlink signal / channel. Alternatively, whether or not to transmit SSB on an SSB-less cell can be signaled via that downlink signal / channel or a separate downlink signal / channel.

[0335] Considering that the base station behavior may vary depending on the information on which triggering condition the UE satisfies to request on-demand SSB, the UL_SSB resource may be set differently depending on the triggering condition. For example, when receiving DL through an SSB-less cell, UL_SSB resource #1 may be set corresponding to a condition (conveniently named condition #1) in which the reception timing (or DL ​​RX synchronization) is determined to be off by a certain threshold (e.g., X ns or Y time samples), and UL_SSB resource #2 may be set corresponding to a condition (conveniently named condition #2) in which the reception sensitivity of a specific SSB index received on the ref-cell falls below a certain threshold. When the UE requests on-demand SSB due to condition #2, it may attempt uplink transmission through UL_SSB resource #2.

[0336] Depending on the situation, the terminal may be able to apply only some of the above triggering conditions. Specifically, the conditions for triggering on-demand SSB may be designated differently depending on whether the SSB-less cell is in an activated or deactivated state. For example, before SCell activation, the operation for triggering on-demand SSB may be allowed depending on whether the time / frequency synchronization obtained through reception of SSB (and / or CSI-RS) on the ref-cell, which is one of the above conditions, can be applied to the SSB-less cell. As another example, after SCell activation, the operation for triggering on-demand SSB may be allowed depending on whether the sensitivity of the signal received through the SSB-less cell and / or the ref-cell, which is one of the above conditions, satisfies a specific condition.

[0337] Figure 19 illustrates the operation of a terminal and a base station according to one embodiment.

[0338] Referring to FIG. 19, a terminal may receive configuration information from a base station via upper layer signaling (1901). The configuration information may include at least one of information about an SSB-less cell, information about a ref-cell, and / or information about on-demand SSB.

[0339] The terminal can perform time synchronization acquisition and / or PL (path loss) estimation based on a reference cell (1902).

[0340] For example, the terminal may transmit an UL signal to the base station to request an OD SSB (1903). For example, one of the on-demand SSB signals may be selected and transmitted based on the satisfaction of the trigger condition of Proposal #3. If the base station independently determines to perform OD SSB transmission, the UL signal transmission for the terminal's OD SSB request may be omitted.

[0341] The base station may transmit a DL signal to the terminal notifying that OD SSB transmission is performed in an SSB-less cell (1904).

[0342] The base station can perform OD SSB transmission in an SSB-less cell (1905).

[0343] The terminal can perform time synchronization acquisition and / or PL (path loss) estimation based on an SSB-less cell (instead of a reference cell) (1906).

[0344] When there are multiple frequency bands operated by a base station, SSB and / or system information, etc. may be periodically transmitted only in a specific frequency band for the purpose of NES, and the corresponding signals / channels may not be periodically transmitted in the remaining frequency bands. In order to support such operation of the base station while also supporting stable communication of the terminal in the corresponding frequency band, this specification proposes an on-demand SSB operation method (specifically, an on-demand SSB function transmitted on an SSB-less cell).

[0345] FIG. 20 illustrates a flow of a method performed by a terminal according to one embodiment.

[0346] The terminal can receive an SSB configuration for the second cell that supports adaptation of SSB transmission through upper layer signaling in at least one of the first cell and the second cell (2005).

[0347] The terminal can receive a downlink signal from at least one of the first cell or the second cell (2010).

[0348] The terminal can determine whether the SSB transmission is performed on the second cell based on the received downlink signal (2015).

[0349] The terminal can receive the SSB of the second cell using the SSB setting based on the determination that the SSB transmission is performed on the second cell.

[0350] The terminal may ignore the SSB setting and skip SSB reception on the second cell based on a determination that the SSB transmission is not performed on the second cell.

[0351] The above downlink signal may be related to RRC (radio resource control) signaling or MAC-CE (medium access control - control element) signaling for activation of the second cell.

[0352] The above SSB setting may include at least one of SSB index information, SSB period information, SSB frequency information, and SSB subcarrier spacing information.

[0353] In the second cell, a first SSB to which the adaptation of the SSB transmission is applied and a second SSB that is periodically transmitted without the adaptation of the SSB transmission can be set.

[0354] The above SSB setting and the above downlink signal may be related to the first SSB.

[0355] The terminal may perform measurements related to the second cell based on at least one SSB. The at least one SSB may include only the SSB of the second cell based on the fact that a reference cell for the second cell is not provided. The at least one SSB may further include the SSB of the reference cell in addition to the SSB of the second cell based on the fact that the reference cell for the second cell is provided.

[0356] Whether a reference cell is provided for the second cell can be explicitly indicated via network signaling.

[0357] The terminal may transmit an uplink signal for requesting the SSB transmission on the second cell through at least one of the first cell or the second cell. The downlink signal may be received as a response to the uplink signal.

[0358] The second cell may be a SCell (secondary cell). The first cell may be a PCell (primary cell), a reference cell for the second cell, or an Scell ​​different from the second cell.

[0359] FIG. 21 illustrates a flow of a method performed by a base station according to one embodiment.

[0360] Referring to FIG. 21, the base station can transmit an SSB configuration for a second cell that supports adaptation of SSB transmission through upper layer signaling in at least one of the first cell and the second cell (2105).

[0361] The base station can determine whether to perform the SSB transmission on the second cell (2110).

[0362] The base station can transmit a downlink signal indicating whether to perform SSB transmission on the second cell through at least one of the first cell or the second cell (2115).

[0363] The base station may transmit the SSB of the second cell using the SSB setting based on determining that the base station will perform the SSB transmission on the second cell.

[0364] The base station may ignore the SSB setting and omit SSB transmission on the second cell based on determining that it will not perform the SSB transmission on the second cell.

[0365] The above downlink signal may be related to RRC (radio resource control) signaling or MAC-CE (medium access control - control element) signaling for activation of the second cell.

[0366] The above SSB setting may include at least one of SSB index information, SSB period information, SSB frequency information, and SSB subcarrier spacing information.

[0367] In the second cell, a first SSB to which the adaptation of the SSB transmission is applied and a second SSB that is periodically transmitted without the adaptation of the SSB transmission can be set.

[0368] The above SSB setting and the above downlink signal may be related to the first SSB.

[0369] The base station may receive a report from the terminal regarding measurements related to the second cell based on at least one SSB. The at least one SSB may include only the SSB of the second cell based on the fact that a reference cell for the second cell is not provided. The at least one SSB may further include the SSB of the reference cell in addition to the SSB of the second cell based on the fact that the reference cell for the second cell is provided.

[0370] Whether a reference cell is provided for the second cell can be explicitly indicated via network signaling.

[0371] The base station may receive an uplink signal requesting SSB transmission on the second cell from the terminal through at least one of the first cell and the second cell. The downlink signal may be transmitted in response to the uplink signal.

[0372] The second cell may be a SCell (secondary cell). The first cell may be a PCell (primary cell), a reference cell for the second cell, or an Scell ​​different from the second cell.

[0373] The embodiments described above are combinations of components and features of the present disclosure in a predetermined form. Each component or feature should be considered optional unless explicitly stated otherwise. Each component or feature may be implemented without being combined with other components or features. Furthermore, it is also possible to form embodiments of the present disclosure by combining some components and / or features. The order of operations described in the embodiments of the present disclosure may be changed. Some components or features of one embodiment may be included in another embodiment or may be replaced with corresponding components or features of another embodiment. It is self-evident that claims that do not have an explicit citation relationship in the patent claims may be combined to form embodiments or incorporated as new claims through post-application amendments.

[0374] It will be apparent to those skilled in the art that the present disclosure may be embodied in other specific forms without departing from the scope of the present disclosure. Therefore, the above detailed description should not be construed as limiting in any respect, but rather as illustrative. The scope of the present disclosure should be determined by a reasonable interpretation of the appended claims, and all modifications within the scope of equivalents of the present disclosure are intended to be included within the scope of the present disclosure.

[0375] The present disclosure may be used in a terminal, base station, or other equipment of a wireless mobile communication system.

Claims

1. In a method performed by a terminal, Receive an SSB configuration for the second cell, which supports adaptation of SSB transmission, through upper layer signaling in at least one of the first cell and the second cell; Receiving a downlink signal from at least one of the first cell or the second cell; and Including determining whether the SSB transmission is performed on the second cell based on the received downlink signal, A method in which the terminal receives the SSB of the second cell using the SSB setting based on a determination that the SSB transmission is performed on the second cell.

2. In paragraph 1, A method in which the terminal ignores the SSB setting and skips SSB reception on the second cell based on a determination that the SSB transmission is not performed on the second cell.

3. In paragraph 1, A method wherein the above downlink signal is related to RRC (radio resource control) signaling or MAC-CE (medium access control - control element) signaling for activating the second cell.

4. In paragraph 1, A method wherein the above SSB setting includes at least one of SSB index information, SSB period information, SSB frequency information, and SSB subcarrier spacing information.

5. In paragraph 1, In the second cell, a first SSB to which the adaptation of the SSB transmission is applied and a second SSB that is periodically transmitted without the adaptation of the SSB transmission are set, A method wherein the above SSB setting and the above downlink signal are related to the first SSB.

6. In paragraph 1, Further comprising performing measurements related to said second cell based on at least one SSB, At least one SSB above, or only including the SSB of the second cell based on the fact that no reference cell is provided for the second cell; or A method further comprising an SSB of the reference cell as well as an SSB of the second cell based on the reference cell being provided for the second cell.

7. In paragraph 6, A method in which whether a reference cell is provided for the second cell is explicitly indicated through network signaling.

8. In paragraph 1, Further comprising transmitting an uplink signal for requesting the SSB transmission on the second cell through at least one of the first cell or the second cell, A method wherein the downlink signal is received as a response to the uplink signal.

9. In paragraph 1, The above second cell is a SCell (secondary cell), A method wherein the first cell is a PCell (primary cell), a reference cell for the second cell, or a SCell different from the second cell.

10. A non-transitory computer-readable recording medium having recorded thereon a program for performing the method described in paragraph 1.

11. In the device, a memory configured to store instructions; and A processor configured to perform operations by executing the above instructions, The operations of the above processor are: Receive an SSB configuration for the second cell, which supports adaptation of SSB transmission, through upper layer signaling in at least one of the first cell and the second cell; Receiving a downlink signal from at least one of the first cell or the second cell; and Including determining whether the SSB transmission is performed on the second cell based on the received downlink signal, A device that receives an SSB of the second cell using the SSB setting based on a determination that the SSB transmission is performed on the second cell.

12. In paragraph 11, Including a transmitter and receiver, The above device is a terminal operating in a wireless communication system.

13. In paragraph 11, The above device is a processing device configured to control a terminal operating in a wireless communication system.

14. In a method performed by a base station, Transmitting an SSB configuration for the second cell, which supports adaptation of SSB transmission, through upper layer signaling in at least one of the first cell and the second cell; determining whether to perform the SSB transmission on the second cell; and Including transmitting a downlink signal indicating whether to perform the SSB transmission on the second cell through at least one of the first cell or the second cell, A method for transmitting SSB of the second cell using the SSB setting based on the base station determining that the SSB transmission will be performed on the second cell.

15. At the base station, a memory configured to store instructions; and A processor configured to perform operations by executing the above instructions, The operations of the above processor are: Transmitting an SSB configuration for the second cell, which supports adaptation of SSB transmission, through upper layer signaling in at least one of the first cell and the second cell; determining whether to perform the SSB transmission on the second cell; and Including transmitting a downlink signal indicating whether to perform the SSB transmission on the second cell through at least one of the first cell or the second cell, A base station that transmits SSB of the second cell using the SSB setting based on the base station determining that the base station will perform the SSB transmission on the second cell.

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