Method and apparatus for transmitting or receiving various synchronization signals in initial access procedure in wireless communication system

Abstract

Disclosed are a method and an apparatus for transmitting or receiving various synchronization signals in an initial access procedure in a wireless communication system. A method, according to one embodiment of the present disclosure, may comprise the steps of: receiving a first synchronization signal group and a second synchronization signal group in a first frequency resource; and performing measurement on the basis of the first synchronization signal group and the second synchronization signal group, in response to reception of the second synchronization signal group in the first frequency resource. The first synchronization signal group and the second synchronization signal group may be distinguished on the basis of at least one of a sequence group or information included in each of the first synchronization signal group and the second synchronization signal group.

Description

Method and device for transmitting or receiving various synchronization signals during the initial access process in a wireless communication system

[0001] The present disclosure relates to a wireless communication system, and more particularly, to a method and apparatus for transmitting or receiving various synchronization signals during an initial access process in a wireless communication system.

[0002] The fifth generation (5G) wireless communication system, the successor to 4G LTE (long-term evolution), is a new, clean-slate mobile communication system characterized by high performance, low latency, and high availability. 5G NR (New Radio) can utilize all available spectrum resources, from low-frequency bands below 1 GHz, to intermediate-frequency bands between 1 GHz and 10 GHz, and to high-frequency (or millimeter wave) bands above 24 GHz. 6G wireless communication systems are being developed based on the underlying technologies of 5G wireless communication.

[0003] The 6G wireless communication system is being developed with the goals of (i) very high data rates per device, (ii) a very large number of connected devices, (iii) global connectivity, (iv) very low latency, (v) reduced energy consumption of 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. Considering the requirements of the 6G system, such as a peak data rate of 1 Tbps per device, an end-to-end latency of 1 ms, a maximum spectrum efficiency of 100 bps / Hz, support for mobility of 1000 km / h, satellite integration, artificial intelligence (AI), autonomous vehicles, extended reality (XR), and haptic communication, various technologies are being researched.

[0004] The technical problem of the present disclosure is to provide a method and device for transmitting or receiving various synchronization signal blocks during an initial access process in a wireless communication system.

[0005] The technical problems to be achieved in the present disclosure are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by a person having ordinary skill in the technical field to which the present disclosure belongs from the description below.

[0006] A method according to one aspect of the present disclosure may include the steps of: receiving a first synchronization signal group and a second synchronization signal group in a first frequency resource; and performing a measurement based on the first synchronization signal group and the second synchronization signal group based on the second synchronization signal group being received in the first frequency resource. The first synchronization signal group and the second synchronization signal group may be distinguished based on a sequence group or at least one of information included in each of the first synchronization signal group and the second synchronization signal group.

[0007] A method according to an additional aspect of the present disclosure may include the steps of transmitting a first synchronization signal group and a second synchronization signal group to one or more terminals in a first frequency resource; and receiving an initial access signal from a first terminal based on a measurement of the first synchronization signal group and the second synchronization signal group of the first terminal among the one or more terminals. The first synchronization signal group and the second synchronization signal group may be distinguished based on one or more of a sequence group or information included in each of the first synchronization signal group and the second synchronization signal group.

[0008] According to the present disclosure, a method and device for transmitting or receiving various synchronization signal blocks during an initial access process in a wireless communication system can be provided.

[0009] The effects that can be obtained from the present disclosure are not limited to the effects mentioned above, and other effects that are not mentioned will be clearly understood by a person having ordinary skill in the art to which the present disclosure pertains from the description below.

[0010] The accompanying drawings, which are incorporated in and are part of the detailed description to aid in understanding the present disclosure, provide embodiments of the present disclosure and, together with the detailed description, describe the technical features of the present disclosure.

[0011] Figure 1 illustrates a flexible network topology to which some examples of the present disclosure may be applied.

[0012] FIG. 2 illustrates an example of a communication system to which some examples of the present disclosure may be applied.

[0013] FIG. 3 illustrates an example of a wireless device to which some examples of the present disclosure may be applied.

[0014] FIG. 4 exemplarily illustrates a communication procedure between a first node and a second node to which some examples of the present disclosure may be applied.

[0015] FIG. 5 illustrates a functional framework for AI operations to which some examples of the present disclosure may be applied.

[0016] FIG. 6 illustrates an example of operations related to AI model training and AI model inference to which some examples of the present disclosure may be applied.

[0017] FIG. 7 illustrates another example of operations related to AI model training and AI model inference to which some examples of the present disclosure may be applied.

[0018] FIG. 8 illustrates another example of operations related to AI model training and AI model inference to which some examples of the present disclosure may be applied.

[0019] FIG. 9 illustrates an electromagnetic spectrum to which some examples of the present disclosure may be applied.

[0020] FIG. 10 illustrates an example of a system information transmission / reception procedure to which some examples of the present disclosure may be applied.

[0021] FIG. 11 exemplarily illustrates a beam management procedure to which some examples of the present disclosure may be applied.

[0022] Figures 12 and 13 illustrate examples of NTN scenarios to which some examples of the present disclosure may be applied.

[0023] FIG. 14 illustrates examples of sensing operations to which some examples of the present disclosure may be applied.

[0024] FIG. 15 illustrates an example of cell DTX / DRX operation to which some examples of the present disclosure may be applied.

[0025] FIG. 16 illustrates an example of carrier aggregation (CA) operation including an SSB-less cell to which some examples of the present disclosure may be applied.

[0026] FIG. 17 illustrates an example of a conditional handover operation to which some examples of the present disclosure may be applied.

[0027] FIG. 18 illustrates an example of a procedure for CSI measurement and reporting to which some examples of the present disclosure may be applied.

[0028] FIG. 19 illustrates examples of on-demand SIB1 operation to which some examples of the present disclosure may be applied.

[0029] FIG. 20 is a diagram showing examples of various SSB transmissions to which the present disclosure can be applied.

[0030] FIG. 21 is a drawing for explaining an example of a method performed by a terminal according to the present disclosure.

[0031] FIG. 22 is a drawing illustrating an example of a method performed by a base station according to the present disclosure.

[0032] FIG. 23 is a diagram illustrating examples of various SSB transmissions at different frequency resource locations according to the present disclosure.

[0033] FIG. 24 is a drawing showing an example of the structure of an SSB to which the present disclosure can be applied.

[0034] FIG. 25 is a diagram showing examples of transmission of various SSBs according to the present disclosure.

[0035] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The detailed description set forth below, together with the accompanying drawings, is intended to explain exemplary embodiments of the present disclosure and is not intended to represent the only embodiments in which the present disclosure may be practiced. The following detailed description includes specific details to provide a thorough understanding of the present disclosure. However, one of ordinary skill in the art will appreciate that the present disclosure may be practiced without these specific details.

[0036] In some cases, to avoid obscuring the concepts of the present disclosure, known structures and devices may be omitted or illustrated in block diagram form focusing on the core functions of each structure and device.

[0037] In the present disclosure, when a component is said to be "connected," "coupled," or "connected" to another component, this may include not only a direct connection but also an indirect connection in which another component exists between them. Furthermore, the terms "comprises" or "has" in the present disclosure specify the presence of the mentioned features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0038] In this disclosure, terms such as “first,” “second,” etc. are used only to distinguish one component from another and are not used to limit the components, and do not limit the order or importance between the components unless specifically stated otherwise. Accordingly, within the scope of this disclosure, a first component in one embodiment 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.

[0039] The terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to limit the scope of the claims. As used in the description of the embodiments and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise.

[0040] In this disclosure, "A or B" can mean "only A," "only B," or "both A and B." In other words, "A or B" in this disclosure can be interpreted as "A and / or B." For example, "A, B or C" in this disclosure can mean "only A," "only B," "only C," or "any combination of A, B and C."

[0041] As used herein, a slash ( / ) or a comma may mean "and / or." For example, "A / B" may mean "A and / or B." Accordingly, "A / B" may mean "only A," "only B," or "both A and B." For example, "A, B, C" may mean "A, B, or C."

[0042] In the present disclosure, “at least one of A and B” may mean “only A,” “only B,” or “both A and B.” Additionally, in the present disclosure, 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.”

[0043] Additionally, in the present disclosure, “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.”

[0044] Additionally, parentheses used in the present disclosure may mean "for example." Specifically, when indicated as "control information (PDCCH)", "PDCCH" may be described as an example of "control information." In other words, "control information" in the present disclosure is not limited to "PDCCH," and "PDCCH" may be described as an example of "control information." Furthermore, even when indicated as "control information (i.e., PDCCH)", "PDCCH" may be described as an example of "control information."

[0045] In the following description, 'when, if, in case of' can be replaced with 'based on'.

[0046] Technical features individually described in one drawing in this disclosure may be implemented individually or simultaneously.

[0047] In the present disclosure, a terminal or user equipment (UE) may be a portable device and may be a first node that receives a signal from a base station / second node / IAB (integrated access backhaul) node.

[0048] In the present disclosure, a base station (BS) may be a second node / IAB node / Transmission-Reception Point (TRP).

[0049] In the present disclosure, higher layer parameters may be parameters configured, pre-configured, or pre-defined for the terminal. For example, a base station or a network may transmit higher layer parameters to the terminal. For example, the higher layer parameters may be transmitted via radio resource control (RRC) signaling or medium access control (MAC) signaling.

[0050] In the present disclosure, "setting or defining" may be interpreted as being set to a device through predefined signaling (e.g., SIB (system information block), MAC, RRC) from a base station or network. In the present disclosure, "setting or defining" may be interpreted as being set to a device through separate signaling or being defined in advance without separate signaling.

[0051] In the present disclosure, transmitting or receiving a channel means transmitting or receiving information or a signal through the channel. For example, transmitting a control channel means transmitting control information or a signal through the control channel. Similarly, transmitting a data channel means transmitting data information or a signal through the data channel.

[0052] The technology described in the present disclosure 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.

[0053] The technology described in the present disclosure 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.

[0054] Network structure

[0055] Figure 1 illustrates a flexible network topology to which some examples of the present disclosure may be applied.

[0056] 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 integrated access backhaul (IAB) nodes, relays, and radio frequency (RF) repeaters, as illustrated in Figure 1, may be applied, or a non-terrestrial network (NTN) 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, and 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, or in the case of a network-controlled repeater, it may not only amplify and forward signals but also adjust its transmission and reception settings based on information provided by the network. For example, NTN nodes could be satellites or aircraft that provide NTN coverage that terrestrial networks struggle to provide. Beyond these examples, various intermediate points can be introduced to improve the network topology.

[0057] 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.

[0058] 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. For example, 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.

[0059] In some examples of the present disclosure, the description of a terminal may equally apply 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 the present disclosure, the description of a base station may equally apply 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. In most cases where there is no additional description of the operations of three or more entities, the communicating entities in the present disclosure are briefly described as terminals and / or base stations (or first nodes and / or second nodes), where 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.

[0060] As such, in some examples of the present disclosure, for the sake of simplicity of explanation, the subjects of the operation may be referred to as terminals and / or base stations (or first nodes and / or second nodes). In addition, the terms terminal and / or base station (or first node and / or second node) may also be interpreted / replaced as in the following examples: For example, the terminal (or first node) and the base station (or 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.

[0061] In the present disclosure, there may be zero or more intermediate points between the base station and the terminal. If an intermediate point exists, it may correspond to an IAB node / relay / RF repeater / NTN node, or a node supporting other functions. The intermediate point may be a node with a fixed location or a node with an unfixed location.

[0062] Systems applicable to this disclosure

[0063] FIG. 2 illustrates an example of a communication system to which some examples of the present disclosure may be applied.

[0064] The communication system (100) applied to the present disclosure 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, 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).

[0065] 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, an IoT device (110f) (e.g., a sensor) can communicate directly with another IoT device (e.g., a sensor) or another wireless device (110a to 110f).

[0066] 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.

[0067] Device applicable to the present disclosure

[0068] FIG. 3 illustrates an example of a wireless device to which some examples of the present disclosure may be applied.

[0069] 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).

[0070] 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.

[0071] 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) comprising 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.

[0072] 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.

[0073] 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.

[0074] 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. Additionally, 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 operational flowcharts disclosed in this document via 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 user data, control information, wireless signals / channels, etc. processed by at least one processor (202) from a baseband signal to an RF band signal. For this purpose, at least one transceiver (206) may include an (analog) oscillator and / or filter.

[0075] 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).

[0076] 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.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] 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.

[0082] 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. 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 backhaul communications, and a wired transceiver may not be included.

[0083] Communication procedures

[0084] FIG. 4 exemplarily illustrates a communication procedure between a first node and a second node to which some examples of the present disclosure may be applied.

[0085] FIG. 4 illustrates operations of a first node (110) (e.g., a terminal) and a second node (120) (e.g., a base station) transmitting and / or receiving data and operations performed prior thereto.

[0086] In step S101, the first node (110) and the second node (120) can perform synchronization. For example, the terminal (110) performs an initial cell search operation. Specifically, the terminal (110) can detect at least one synchronization signal transmitted from the base station (120) according to a predefined rule. Here, the synchronization signal can include a plurality of synchronization signals (e.g., a primary synchronization signal, a secondary synchronization signal) classified according to a structure or purpose. Through this, the terminal (110) can confirm the boundaries of the frame, subframe, slot, and / or symbol of the base station (120) and obtain information (e.g., a cell identifier) ​​about the base station (120).

[0087] In step S103, the first node (110) can obtain system information transmitted from the second node (120). For example, 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., the channel used, whether it is provided in an on-demand manner), etc., and can be classified into, for example, a master information block (MIB) and a system information block (SIB). If necessary, the terminal (110) can transmit a signal requesting system information before receiving the system information. Such requesting and providing of system information may be performed after a random access procedure described below.

[0088] In step S105, the first node (110) and the second node (120) can perform a random access procedure. For example, 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 a random access procedure based on information related to a random access channel of the base station (120) obtained through system information (e.g., channel position, channel structure, structure of a supported preamble, etc.). For example, the terminal (110) may transmit a preamble (e.g., message 1 (MSG1)) over a random access channel, receive a random access response (RAR) message (e.g., message 2 (MSG2)), transmit a message (e.g., message 3 (MSG3)) including information related to the terminal (110) (e.g., identification information) using scheduling information included in the RAR message to the base station (120), and receive a message for contention resolution and / or connection establishment (e.g., message 4 (MSG4)). As another example, MSG1 and MSG3 may be transmitted and received as one message (e.g., message A (MSG A)), or MSG2 and MSG4 may be transmitted and received as one message (e.g., message B (MSG B)).

[0089] In step S107, the first node (110) and the second node (120) can perform signaling of control information. For example, 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 transmission 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.

[0090] In step S109, the first node (110) and the second node (120) can transmit and / or receive data. For example, 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 information bits. For example, 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.

[0091] 6G system core technologies

[0092] As core implementation technologies of the 6G system, technologies such as artificial intelligence (AI), THz (terahertz) communication, optical wireless technology, free space optics (FSO) backhaul network, massive MIMO (multiple input multiple output) 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.

[0093] artificial intelligence

[0094] 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. 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.

[0095] FIG. 5 illustrates a functional framework for AI operations to which some examples of the present disclosure may be applied.

[0096] Below, to explain AI (or AI / ML (machine learning)) in more detail, the terms can be defined as follows.

[0097] - Data collection: Data collected from network nodes, management entities, or terminals as a basis for AI model training, data analysis, and inference.

[0098] - 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.

[0099] - 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.

[0100] - AI / ML inference: The process of making predictions or inducing decisions based on collected data and the AI ​​model using a trained AI model.

[0101] Referring to FIG. 5, the data collection function (10) is a function that collects input data and provides processed input data to the model training function (20) and the model inference function (30).

[0102] Examples of input data may include measurements from terminals or other network entities, feedback from actors, and output from AI models.

[0103] The data collection function (10) performs data preparation based on input data and provides input data processed through the data preparation. Here, the data collection function (10) does not perform data preparation specific to each AI algorithm (e.g., data pre-processing and cleaning, formatting, and transformation), but can perform data preparation common to all AI algorithms.

[0104] After the data preparation process is performed, the data collection function (10) may provide training data (11) to the model training function (20) and may provide inference data (12) to the model inference function (30). Here, the training data (11) may correspond to data required as input for the AI ​​model training function (20), and the inference data (12) may correspond to data required as input for the AI ​​model inference function (30).

[0105] The data collection function (10) may be performed by a single entity (e.g., a terminal, a RAN node, a network node, etc.), but may also be performed by multiple entities. In this case, training data (11) and inference data (12) may be provided to the model training function (20) and model inference function (30), respectively, from multiple entities.

[0106] The model training function (20) may correspond to a function that performs AI model training, validation, and testing, which can generate model performance metrics as part of the AI ​​model testing procedure. If necessary, the model training function (20) may also be responsible for data preparation (e.g., data pre-processing and cleaning, formatting, and transformation, etc.) based on training data (11) provided by the data collection function (10).

[0107] Here, model deployment / update (13) can be used to initially deploy a trained, validated and tested AI model to the model inference function (30) or to provide an updated model to the model inference function (30).

[0108] The model inference function (30) may correspond to a function that provides AI model inference output (16) (e.g., prediction or decision). If applicable, the model inference function (30) may provide model performance feedback (14) to the model training function (20). In addition, the model inference function (30) may also be responsible for data preparation (e.g., data pre-processing and cleaning, formatting and transformation, etc.) based on inference data (12) provided by the data collection function (10), if necessary.

[0109] Here, output (16) refers to the inference output of the AI ​​model generated by the model inference function (30), and the details of the inference output may vary depending on the use case.

[0110] Model performance feedback (14) can be used to monitor the performance of the AI ​​model, if available, and this feedback may be omitted.

[0111] An actor function (40) is a function that receives an output (16) from a model inference function (30) and triggers or performs a corresponding task / action. The actor function (40) can trigger tasks / actions for other entities (e.g., one or more terminals, one or more RAN nodes, one or more network nodes, etc.) or for itself.

[0112] Feedback (15) can be used to derive training data (11), inference data (12), or to monitor the performance of the AI ​​model, its impact on the network, etc.

[0113] Meanwhile, the definitions of training / validation / test in data sets used in AI / ML can be distinguished as follows.

[0114] - Training data: refers to a data set for learning a model.

[0115] - Validation data: This refers to a dataset used to validate a model that has already completed training. Validation data can typically be used to prevent overfitting of the training data set. It can also be used to select the best model among the various models learned during the training process. Therefore, validation can be considered a type of learning.

[0116] - Test data: This refers to the data set for final evaluation. This data is unrelated to learning.

[0117] For example, the training and validation data can be divided into an 8:2 or 7:3 ratio within the entire data set. Alternatively, the training data:validation data:test data can be divided into a 6:2:2 ratio within the entire data set.

[0118] The level of cooperation can be defined as follows depending on whether the base station and the terminal have capabilities for AI / ML functions, and variations due to combination of multiple levels or separation of any one level are also possible.

[0119] Category 0a: This category corresponds to a no-collaboration framework. In this case, AI / ML algorithms are purely implementation-based and may not require any changes to the wireless interface.

[0120] Category 0b: Frameworks that involve a wireless interface modified to fit efficient implementation-based AI / ML algorithms, but without collaboration.

[0121] Category 1: This category applies to cases where inter-node support is required to improve the AI / ML algorithms of each node. For example, this applies when a terminal receives support from a base station (for training, adaptation, etc.), and vice versa. At this level, model exchange between network nodes is not required.

[0122] Category 2: This applies to cases where joint ML tasks can be performed between terminals and base stations. This level requires exchange of AI / ML model commands or network nodes.

[0123] The functions exemplified in FIG. 5 above may be implemented in a RAN node (e.g., a base station, a TRP, a CU of a base station, etc.), a network node, an OAM (operation administration maintenance) of a network operator, or a terminal.

[0124] Alternatively, two or more entities, such as a RAN, a network node, a network operator's OAM, or a terminal, may cooperate to implement the functions illustrated in FIG. 5. For example, one entity may perform some of the functions of FIG. 5, and another entity may perform the remaining functions. In this way, since some of the functions illustrated in FIG. 5 are performed by a single entity (e.g., a terminal, a RAN node, a network node, etc.), the transmission / provision of data / information between each function may be omitted. For example, if the model training function (20) and the model inference function (30) are performed by the same entity, the transmission / provision of model deployment / update (13) and model performance feedback (14) may be omitted.

[0125] Alternatively, any one of the functions illustrated in FIG. 5 may be performed collaboratively by two or more entities, including a RAN, a network node, a network operator's OAM, or a terminal. This may be referred to as a split AI operation.

[0126] FIG. 6 illustrates an example of operations related to AI model training and AI model inference to which some examples of the present disclosure may be applied.

[0127] For example, the AI ​​model training function may be performed by a network node (e.g., a core network node, an OAM of a network operator, etc.), and the AI ​​model inference function may be performed by a RAN node (e.g., a base station, a TRP, a CU of a base station, etc.).

[0128] Step 1: RAN node 1 and RAN node 2 can transmit input data (e.g., training data) for AI model training to the network node. Here, RAN node 1 and RAN node 2 can also transmit data collected from the terminal (e.g., terminal measurements related to RSRP (reference signal received power), RSRQ (reference signal received quality), SINR (signal to interference-plus-noise ratio) of the serving cell and neighboring cells, terminal location, speed, etc.) to the network node.

[0129] Step 2: Network nodes can train AI models using the received training data.

[0130] Step 3: The network node may distribute / update the AI ​​model to RAN node 1 and / or RAN node 2. RAN node 1 (and / or RAN node 2) may also continue model training based on the received AI model.

[0131] For convenience of explanation, we assume that the AI ​​model is deployed / updated only to RAN node 1.

[0132] Step 4: RAN node 1 can receive input data (e.g., inference data) for AI model inference from the terminal and RAN node 2.

[0133] Step 5: RAN node 1 can perform AI model inference using the received inference data to generate output data (e.g., prediction or decision).

[0134] Step 6: If applicable, RAN node 1 may send model performance feedback to the network nodes.

[0135] Step 7: RAN node 1, RAN node 2, and the terminal (or 'RAN node 1 and the terminal', or 'RAN node 1 and RAN node 2') may perform actions based on the output data. For example, in the case of a load balancing operation, the terminal may move from RAN node 1 to RAN node 2.

[0136] Step 8: RAN node 1 and RAN node 2 can transmit feedback information to the network nodes.

[0137] FIG. 7 illustrates another example of operations related to AI model training and AI model inference to which some examples of the present disclosure may be applied.

[0138] For example, both AI model training functions and AI model inference functions can be performed by RAN nodes (e.g., base stations, TRPs, CUs of base stations, etc.).

[0139] Step 1: The terminal and RAN node 2 can transmit input data (e.g., training data) for AI model training to RAN node 1.

[0140] Step 2: RAN node 1 can train an AI model using the received training data.

[0141] Step 3: RAN node 1 can receive input data (e.g., inference data) for AI model inference from the terminal and RAN node 2.

[0142] Step 4: RAN node 1 can perform AI model inference using the received inference data to generate output data (e.g., prediction or decision).

[0143] Step 5: RAN node 1, RAN node 2, and the terminal (or 'RAN node 1 and the terminal', or 'RAN node 1 and RAN node 2') may perform actions based on the output data. For example, in the case of a load balancing operation, the terminal may move from RAN node 1 to RAN node 2.

[0144] Step 6: RAN node 2 may transmit feedback information to RAN node 1.

[0145] FIG. 8 illustrates another example of operations related to AI model training and AI model inference to which some examples of the present disclosure may be applied.

[0146] For example, the AI ​​model training function may be performed by a RAN node (e.g., a base station, a TRP, a CU of a base station, etc.), and the AI ​​model inference function may be performed by a terminal.

[0147] Step 1: The terminal may transmit input data (e.g., training data) for AI model training to the RAN node. Here, the RAN node may collect data (e.g., terminal measurements related to RSRP, RSRQ, SINR of the serving cell and neighboring cells, terminal location, speed, etc.) from various terminals and / or from other RAN nodes.

[0148] Step 2: RAN nodes can train AI models using the received training data.

[0149] Step 3: The RAN node can distribute / update the AI ​​model to the terminal. The terminal can also continue model training based on the received AI model.

[0150] Step 4: Input data (e.g., inference data) for AI model inference can be received from the terminal and RAN node (and / or from another terminal).

[0151] Step 5: The terminal can perform AI model inference using the received inference data to generate output data (e.g., prediction or decision).

[0152] Step 6: If applicable, the terminal may send model performance feedback to the RAN node.

[0153] Step 7: The terminal and RAN node can perform actions based on the output data.

[0154] Step 8: The terminal may transmit feedback information to the RAN node.

[0155] THz communication (terahertz communication)

[0156] Data transmission 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 (the 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 6G cellular capacity. 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.

[0157] FIG. 9 illustrates an electromagnetic spectrum to which some examples of the present disclosure may be applied.

[0158] Key characteristics of THz communications include (i) the widely available bandwidth to support very high data rates, and (ii) the high path loss at high frequencies (which necessitates highly directional antennas). The narrow beamwidths generated by highly directional antennas reduce interference. The small wavelength of THz signals allows for a significantly 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 technologies to overcome range limitations.

[0159] Transmitting system information (e.g., MIB) in a cell in the THz frequency band can be inefficient because the beam width in high-frequency bands narrows, requiring more beam sweeps to cover the entire cell area. This method is particularly inefficient when there are only a few users within the cell.

[0160] FIG. 10 illustrates an example of a system information transmission / reception procedure to which some examples of the present disclosure may be applied.

[0161] The example of Fig. 10 is applicable not only to THz communication environments but also to 6G communication environments where THz communication is not applicable. Furthermore, the procedure illustrated in Fig. 10 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 Fig. 10.

[0162] In step S1010, the second node (120) (e.g., base station) can transmit system information of cell #1 via cell #2. For example, the base station provides at least two cells, cell #1 uses a THz frequency band, and cell #2 uses a frequency band other than the THz frequency band. Here, the system information may include at least one of an SFN (system frame number), a PDCCH configuration for SIB1, cell barring, cell re-selection, and subcarrier spacing generated in a higher layer, and may include at least one of an SFN, a half frame indicator, and an SSB index (synchronization signal / PBCH (physical broadcast channel) block index) generated in a physical layer. For this purpose, as an example, cell #1 and cell #2 may have a relationship of a secondary cell and a primary cell.

[0163] At step S1030, the first node (110) (e.g., terminal) can acquire synchronization for cell #1. Synchronization can be acquired by detecting a synchronization signal. Typically, synchronization is acquired before receiving system information, but 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 terminal can acquire synchronization based on the system information. Alternatively, synchronization acquisition can be performed before step S1010.

[0164] At step S1050, the first node (110) may transmit a signal for accessing cell #1. For example, the signal may include a random access preamble. The structure of this signal and the resources (e.g., channels) for transmitting the signal may be identified through system information. Thereafter, at step S1070, the first node (110) and the second node (120) may perform an access procedure for cell #1 and communicate.

[0165] The procedure described with reference to FIG. 10 may be performed when the first node (110) initially connects to cell #1 of the second node (120). Alternatively, a similar procedure may be performed when the first node (110) hands over to cell #1 of the second node (120). 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 second node (120).

[0166] Communications in the THz band are expected to experience extremely severe path loss, and to overcome this, terminals and base stations may be required to use very 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 movement or movement of the terminals, frequent re-alignment is required, which can lead to link instability.

[0167] FIG. 11 exemplarily illustrates a beam management procedure to which some examples of the present disclosure may be applied.

[0168] Although FIG. 11 illustrates an example of a procedure for searching and / or selecting beams for THz communication, this procedure is not limited to a THz environment and can also be applied to a 6G communication environment where THz communication is not applied.

[0169] Here, beam may be interpreted as other terms having equivalent technical meanings that can distinguish beams, such as 'spatial domain filter', 'spatial domain transmit filter', 'spatial domain receive filter', reference signal (RS) resource that distinguishes beams, SSB index, etc.

[0170] In step S1110, the second node (120) (e.g., base station) can set resources for beam management to the first node (110) (e.g., terminal). 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 an existing downlink signal / channel 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 an existing downlink signal / channel (e.g., SSB, PDSCH (physical downlink shared channel), 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. For example, a signal transmitted based on a dedicated port defined / set for beam search can be included in the technical concept according to the present embodiment.

[0171] In step S1130, the second node (120) (e.g., base station) transmits measurement signals using a plurality of transmission beams. For example, the measurement signals may include at least one of a reference signal and a synchronization signal. At this time, the measurement signals may be transmitted as many times as the number of beams that require measurement, and may also be transmitted in a multi-beam transmission method that forms a plurality of beams simultaneously to reduce sweeping time. Here, the multi-beam transmission may be performed based on at least one of a multi-panel, a sub-array, and a true time delay (TTD).

[0172] In step S1050, a first node (110) (e.g., a terminal) may transmit a feedback signal to a second node (120) (e.g., a base station). The feedback signal may indicate at least one beam selected by the terminal. The terminal may select at least one preferred beam based on the measurement signals received in step S1030.

[0173] In step S1070, the first node (110) and the second node (120) can perform communication. For example, the second node (120) can perform transmission to the first node (110) using the reception beam of the first node (110) selected in step S1050. If channel reciprocity is established, the transmission beam of the first node (110) can also be determined through steps S1030 and S1050, so that the transmission operation from the first node (110) can also be performed using a beam that has a reciprocal relationship with the beam selected in step S1050. If channel reciprocity is not established, a procedure including transmission of measurement signal(s) by the first node (110) and transmission of feedback signal(s) by the second node (120) may be performed first to determine the transmission beam of the first node (110).

[0174] non-terrestrial networks (NTN)

[0175] Figures 12 and 13 illustrate examples of NTN scenarios to which some examples of the present disclosure may be applied.

[0176] NTN can represent a network or network segment that uses radio frequency (RF) resources mounted on a satellite (or unmanned aerial system (UAS) platform).

[0177] Figure 12 shows an example of a typical scenario of NTN based on transparent payload, and Figure 13 shows an example of a typical scenario of NTN based on regenerative payload.

[0178] Referring to Figure 12, a satellite (or UAS platform) can establish a service link with a terminal. The satellite (or UAS platform) can be connected to a gateway via a feeder link. The satellite can be connected to a data network via the gateway. The beam footprint can refer to the area where the signal transmitted by the satellite can be received.

[0179] Referring to Figure 13, a satellite (or UAS platform) can establish a service link with a terminal. A satellite (or UAS platform) connected to a terminal can be connected to another satellite (or UAS platform) via an inter-satellite link (ISL). The other satellite (or UAS platform) can be connected to a gateway via a feeder link. Based on the regenerated payload, the satellite can be connected to a data network through another satellite and the gateway. If an ISL does not exist between the satellite and another satellite, a feeder link between the satellite and the gateway may be required.

[0180] Figures 12 and 13 are merely examples of NTN scenarios, and NTN can be implemented based on various scenarios. For example, a satellite (or UAS platform) can implement a transparent or regenerative (e.g., with onboard processing) payload. For example, a satellite (or UAS platform) can generate multiple beams across a designated service area depending on the field of view of the satellite (or UAS platform). For example, the field of view of the satellite (or UAS platform) can vary depending on the onboard antenna diagram and the minimum elevation angle.

[0181] For example, a transparent payload may include radio frequency filtering, frequency conversion, and amplification. Therefore, the waveform signal repeated by the payload may remain unchanged.

[0182] For example, a regenerative payload may include radio frequency filtering, frequency conversion and amplification, demodulation / decoding, switching and / or routing, and coding / modulation. For example, a regenerative payload may be substantially equivalent to mounting all or part of a base station function on a satellite (or UAS platform).

[0183] Integrated Sensing and Communication (ISAC)

[0184] Wireless sensing is a technology that uses radio frequencies to determine the instantaneous linear velocity, angle, distance (or range) of an object, and thus obtain 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, such as 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 communications network to a wireless communication and sensing network.

[0185] FIG. 14 illustrates examples of sensing operations to which some examples of the present disclosure may be applied.

[0186] Specifically, Fig. 14(a) shows an example of a monostatic sensing operation using a sensing receiver and a sensing transmitter located in the same location. Fig. 14(b) shows an example of a bistatic sensing operation using a sensing receiver and a sensing transmitter located in separate locations. A sensing signal transmitted from a sensing transmitter is reflected / scattered by a sensing object, and the sensing receiver can receive the signal, and extract / obtain sensing data based on the received signal. A sensing result can be generated / determined through appropriate processing of the sensing data. The sensing result can be provided to a trusted third-party entity / service outside the 3GPP system through an entity / service within the 3GPP system.

[0187] Network Energy Saving (NES)

[0188] 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 providers. 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. For example, various technologies for reducing energy consumption in 5G wireless communication systems are being discussed under the term "network energy savings" (NES).

[0189] Depending on the application of NES technology, the base station can perform operations such as controlling on / off for a certain time duration in the time domain, controlling transmission / reception resources for terminal-common or terminal-specific signals / channels, changing the amount of frequency domain resources, controlling transmission power, or turning on / off an antenna port, transmission-reception point (TRP), etc. in the spatial domain.

[0190] For example, a base station may identify the NES solution(s) to be applied, perform signaling to the NES, and perform actions on the NES.

[0191] 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. The NES solution(s) to be applied may be adaptively selected or predefined based on current conditions (e.g., cell load level, characteristics of connected terminals, etc.).

[0192] A base station that has identified NES solution(s) performs signaling for the NES. 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 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.

[0193] Based on the signaled NES-related information, the base station can perform operations for the NES. For example, based on system information, configuration information, and control information conveyed via signaling, the base station can turn on / off transmission and reception of specific signals, turn on / off elements in the spatial domain, or adjust resources for transmission and reception of measurement signals.

[0194] Examples of NES solutions that can be implemented using these procedures include:

[0195] Intra-system energy saving: A RAN node may request a neighboring RAN node to switch at least one SSB beam into its inactive cell, or may perform paging using a limited set of beams to an inactive terminal (e.g., a stationary terminal).

[0196] Inter-system energy savings: NG-RAN nodes that own capacity booster cells can autonomously transition those cells to an inactive state.

[0197] SSB-less cells: If SSB or SSB-based RRM (radio resource management) measurement timing configuration (SMTC) configuration is not provided for a specific cell (e.g., secondary cell (SCell) or primary cell (PCell)), the UE may obtain timing reference and automatic gain control (AGC) source from another serving cell. In frequency range 1 (FR1) or FR2, the base station may configure intra-band carrier aggregation (CA) or inter-band CA including cells without SSB transmission, in which case SSB / SIB transmission may be triggered by a wake up signal (WUS) of the UE. Accordingly, since the period of common channels / signals such as SSB is increased, the base station may stay in sleep state for a longer time.

[0198] Cell DTX (discontinuous transmission) / DRX (discontinuous reception): 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) may be commonly configured for terminals within a cell having the feature. Here, the cell DTX pattern and the cell DRX pattern may be configured and activated separately, and up to two cell DTX / DRX patterns may be configured per MAC entity. When cell DTX is configured and activated, at least one of monitoring for a semi-persistent scheduling (SPS) opportunity or monitoring a PDCCH may be stopped during the cell DTX inactivity period. When cell DRX is configured and activated, at least one of transmission on a configured grant (CG) resource or transmission of a scheduling request (SR) may be stopped during the cell DRX inactivity period. Cell DTX / DRX can be activated / deactivated via RRC signaling or L1 (layer 1) group common signaling.

[0199] Parameters such as active duration and cycle may be configured for cell DTX / DRX. Active duration is the period during which the UE receives a PDCCH or SPS opportunity and waits to transmit SR or CG, and cycle may specify 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 may be common. If the base station recognizes an emergency call or a public safety-related service (e.g., multimedia priority service (MPS) or mission critical service (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 may be required between the active period of the connected mode DRX of the UE and the active period 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.

[0200] Conditional handover (CHO): A CHO procedure performed in a manner in which the execution of a handover is determined by the UE may be used while NES technology is applied (e.g., when the cell activates or deactivates cell DTX / DRX). In this case, the UE may use an NES-specific CHO event to initiate CHO to a candidate cell, and reception of a DCI activating the CHO condition(s) set by the NES event indication may be applied as an additional triggering condition for this.

[0201] Spatial and Power Domain Adaptation: To support the base station for transceiver muting and / or transmit power adaptation, the UE may be configured to report multiple CSI quantities 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.

[0202] Cell DTX / DRX

[0203] To enable base stations to operate in sleep mode for relatively long periods of time without frequent wake-ups, base station DTX / DRX has been introduced for NES purposes. The base station can reduce energy consumption by utilizing DTX transmission under low system load conditions by configuring cell DTX and setting the on-duration of terminals' C-DRX within the active period of the cell DTX.

[0204] FIG. 15 illustrates an example of cell DTX / DRX operation to which some examples of the present disclosure may be applied.

[0205] A second node (120) (e.g., a base station) can transmit system information to a first node (110) (e.g., a terminal). Accordingly, the first node (110) can check information related to the cell DTX / DRX of the second node (120).

[0206] For example, system information may include MIB, SIB1, etc. In relation to NES technology, MIB may include information related to cell barring (e.g., cellBarred), and SIB1 may include information related to cell barring state (e.g., cellBarredNES). For example, if cellBarred included in MIB is set to a value indicating that it is not barred (e.g., notBarred), a terminal may determine that the cell is not barred, regardless of whether it supports NES cell DTX / DRX. For example, if cellBarred included in 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.

[0207] For example, if a terminal has a capability to support NES cell DTX / DRX, the terminal can check SIB1 to determine a cell barring status. For example, if cellBarred of MIB is set to barred and cellBarredNES is absent in SIB1, a terminal supporting NES cell DTX / DRX can treat the cell as barred and perform cell reselection to another cell. For example, if cellBarred of MIB is set to barred and cellBarredNES is included in SIB1, a terminal supporting NES cell DTX / DRX can determine that the cell is not barred.

[0208] In the example of FIG. 15, it is assumed that the terminal has the capability to support NES cell DTX / DRX, and cellBarred of MIB is set to notBarred, or cellBarred of MIB is set to barred and SIB1 includes cellBarredNES. Accordingly, the terminal can perform a random access procedure to connect to the base station, and then perform communication. For example, the base station can perform a cell DTX / DRX operation, and transmit configuration information related to the cell DTX / DRX operation to the terminal. 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., cellDTRX-RNTI included in physicalCellGroupConfig, DCI-related information such as the size of DCI format 2_9, etc.).

[0209] Thereafter, the base station can transmit control information related to cell DTX / DRX to the terminal. The control information related to cell DTX / DRX can include DCI having a designated format (e.g., DCI format 2_9). If an operation for a serving cell according to at least one of a cell DTX operation and a cell DRX operation is configured by configuration information (e.g., cellDTXDRX-Config included in servingcell-config), the terminal can check a set of search spaces (e.g., a Type3-PDCCH CSS set) for monitoring a PDCCH conveying control information of a designated format during an active time through a higher layer parameter (e.g., SearchSpace included in PDCCH-Config), and can obtain a location of information about the serving cell within the control information through a higher layer parameter (e.g., positionInDCI-cellDTRX included in ServingCell-config). Then, the terminal can obtain control information based on the identified set of search spaces and the location.

[0210] 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 NES-mode indicators (e.g., NES-specific CHO execution conditions, etc.), 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 supplementary uplink (SUL) carrier, the indication of activation or deactivation of cell DRX by the cell DTX / DRX indicator may be applied to both the uplink (UL) carrier and the SUL carrier.

[0211] After that, the terminal and the base station can perform communication based on the cell DTX / DRX. Specifically, the base station can turn on / off the transmission and reception of signals according to the settings related to the cell DTX / DRX, so that the terminal can selectively monitor the signal from the base station. During the DTX-OFF duration, the base station can enter a sleep mode to reduce energy consumption. For example, the base station DTX cycle can be aligned with the cycle of the terminal DRX. The base station DTX-ON duration can completely cover the DRX-ON duration of the terminal. Furthermore, the base station can align the transmission on Xn (base station-to-base station interface) / NG (interface between 5G RAN and 5G core network) and the transmission on Uu (interface between terminal and network) for NES purposes. The DTX / DRX mechanism triggers switching of reference signal resource sets, and the base station can perform a dormancy-like behavior of rarely or not transmitting SSB, SIB, and CSI-RS to reduce energy consumption. The terminal can rarely or not receive downlink signals / channels depending on the configuration of the base station. Once the base station DTX / DRX operation is triggered, the terminal can discontinuously receive the corresponding CSI-RS, SSB, or PDCCH during the DTX / DRX OFF duration.

[0212] SSB-less cells

[0213] FIG. 16 illustrates an example of carrier aggregation (CA) operation including an SSB-less cell to which some examples of the present disclosure may be applied.

[0214] In the example of Figure 16, it is assumed that the SSB-less cell is an SCell in the CA, but the SSB-less cell may also be a PCell in the CA.

[0215] A second node (120) (e.g., a base station) can transmit configuration information for an SCell to a first node (110) (e.g., a terminal). For example, the base station can transmit configuration information for CA to provide a service to the terminal through a CA operation. Here, the CA operation may be an intra-band CA or an inter-band CA. For example, the configuration information for an SCell may include information (e.g., sCellToAddModList) including information for adding an SCell, 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. Accordingly, the terminal can determine the configuration for the CA operation and perform communication using the PCell and SCell of the base station.

[0216] For example, the terminal can determine that the SCell is an SSB-less SCell based on information related to the downlink frequency included in the configuration information, and can check related parameters. For example, the terminal can determine that the SCell is an SSB-less SCell by checking the presence of a parameter indicating that the SCell is an SSB-less SCell (e.g., SSBlessSCell), and can check the timing reference and AGC source for the SCell based on information about the reference cell (e.g., referenceCell). In the example of Fig. 16, the reference cell can be the PCell. Therefore, the terminal can use the PCell as a timing reference and AGC source for communication in the SCell. For example, the reference of the SSB-less cell can be (another) cell, TRP, CORESET pool (control resource set pool), (additional) PCI (physical cell ID), etc.

[0217] Conditional Handover (CHO)

[0218] FIG. 17 illustrates an example of a conditional handover operation to which some examples of the present disclosure may be applied.

[0219] The order of the operations illustrated in Fig. 17 may vary depending on the case.

[0220] A second node (120) (e.g., a base station) can transmit configuration information for CHO to a first node (110) (e.g., a terminal). The configuration information for CHO can include information related to conditional reconfiguration (e.g., ConditionalReconfiguration, CondReconfigToAddModList), information related to configuration for reporting (e.g., ReportConfigNR). For example, the information related to configuration for reporting can include information related to events related to reporting, identifiers of the events (e.g., condEventId), information indicating whether it is a NES-specific CHO event (e.g., nesEvent), etc. In the example of FIG. 17, it is assumed that event information indicating that it is a NES-specific CHO event is received.

[0221] A base station may transmit information for enabling an NES-specific CHO execution condition to a terminal. 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, and may be, for example, 1-bit information that indicates enabling the NES-specific CHO execution condition when a related upper layer parameter (e.g., nesEvent) is set and a serving cell of a related block in the DCI is a primary cell.

[0222] Afterwards, the terminal can perform measurements and transmit a measurement report to the base station. The base station can determine a CHO based on the measurement report and perform signaling for a handover request with the adjacent / neighboring base station(s) indicated by the measurement report. The base station can determine the adjacent base station(s) that have confirmed admission through signaling as candidate base station(s) and transmit information about the candidate base station(s) to the terminal. Accordingly, the terminal can evaluate the CHO execution conditions for the candidate base station(s). Based on the evaluation result, if a candidate cell satisfying the conditions is determined, the terminal can perform detachment for the old cell and synchronization for the new cell.

[0223] For example, based on event information indicating that the event is an NES-specific CHO event received by the terminal in the previous procedure and information enabling an NES-specific CHO execution condition, the terminal can determine whether the event is satisfied. For example, if an NES-mode indicator is received through a lower layer and conditional triggering configuration information (e.g., condTriggerConfig) includes information indicating that the event is an NES-specific CHO event (e.g., nesEvent), 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.

[0224] Channel State Information (CSI) Measurement and Reporting

[0225] FIG. 18 illustrates an example of a procedure for CSI measurement and reporting to which some examples of the present disclosure may be applied.

[0226] A second node (120) (e.g., a base station) can transmit configuration information for CSI to a first node (110) (e.g., a terminal). The configuration information for CSI can include information related to a reference signal (e.g., a CSI-RS) resource or a resource set for CSI (e.g., time-frequency resource information, sequence information, power information, etc.), information related to CSI reporting (e.g., report item (quantity) information, report type information, report resource information, codebook information, etc.), information related to CSI measurement, etc.

[0227] For example, to assist the base station with transceiver muting and / or transmit power adaptation of the base station, the terminal may be configured to report multiple CSI entries in a CSI report based on multiple sub-configurations. For example, each sub-configuration may correspond to a spatial domain adaptation pattern (e.g., a subset of available spatial elements) and / or a power offset. With respect to CSI reporting, a higher layer parameter included in the configuration information (e.g., CSI-ReportConfig) may include a list of sub-configurations, and each sub-configuration may be identified by an identifier (e.g., csi-ReportSubConfigID). For example, each sub-configuration may correspond to a list of at least one CSI-RS resource, or may correspond to a subset of CSI-RS antenna ports, and / or may correspond to power-related parameters of the CSI-RS resource(s) (e.g., power control offset-related parameters (e.g., powerControlOffset) and / or power offset for a PDSCH associated with the CSI-RS).

[0228] For example, an information element (IE) for an aperiodic trigger state list for CSI may include a trigger list parameter for a CSI reporting sub-configuration. This parameter may include a list of sub-configuration ID(s) of N sub-configuration(s) among L configured sub-configurations within a CSI reporting configuration that are associated with triggering states for aperiodic CSI reporting on an uplink data channel (e.g., a physical uplink shared channel (PUSCH)).

[0229] For example, an IE for a CSI reporting configuration may include parameters for a list of CSI reporting sub-configuration ID(s) to be added / modified or released. Port subset indicators and a list of non-zero power (NZP) CSI-RS resources may not be configured simultaneously in the same CSI reporting configuration.

[0230] For example, an IE for a CSI reporting sub-configuration may include a port-subset indicator parameter, an NZP CSI-RS resource list parameter, and a power offset parameter.

[0231] The port-subset indicator parameter may indicate the number of ports of the NZP CSI-RS resources indicated in the NZP CSI-RS resource list (the value of which is equal to the number of ports of the corresponding NZP CSI-RS resources) and the (sub)set of CSI-RS antenna ports used for CSI calculation of the sub-configuration. Each bit in the bit string of the port-subset indicator corresponds to an antenna port, and if any bit is set to 1, the corresponding port may be enabled for CSI calculation corresponding to the sub-configuration, and if any bit is set to 0, the corresponding port may not be enabled for CSI calculation corresponding to the sub-configuration.

[0232] The NZP CSI-RS resource list parameter may indicate a list of NZP CSI-RS resources for a sub-configuration, which is a (sub)set of NZP CSI-RS resource(s) of a CSI-RS resource set for channel measurements associated with the sub-configuration of the CSI reporting configuration. The values ​​0, 1, 2, ... may mean the first, second, third, ... NZP CSI-RS resources of the CSI-RS resource set.

[0233] When the power offset parameter is set for an NZP CSI-RS resource, it may indicate that a power offset is applied between the PDSCH RE (resource element) and the NZP CSI-RS RE by the difference in the value of the power offset parameter from the value of the power control offset parameter.

[0234] When a configuration for CSI includes multiple sub-configurations, when interpreting the configuration information for CSI, the terminal may determine CSI-RS resources, CSI-RS port mapping, power offset, codebook type, report items, etc. by considering the sub-configurations. When configuration information related to CSI reporting including sub-configurations (e.g., CSI-ReportConfig) is provided to the terminal, the terminal may not expect that a higher layer parameter related to a report item (e.g., reportQuantity) is set to 'cri-RSRP', 'cri-SINR', 'cri-SINR-Index', 'cri-RSRP-Index', 'none', 'ssb-Index-RSRP', 'ssb-Index-SINR', 'ssb-Index-RSRP-Index', 'ssb-Index-SINR-Index' or 'tdcp' (wherein CRI corresponds to a CSI-RS resource index, and tdcp corresponds to time domain channel properties). Additionally, when the type of CSI reporting is set to semi-persistent CSI reporting or aperiodic CSI reporting, the base station can activate / trigger only some of the sub-configurations configured for the UE through MAC-CE (control element) or DCI (downlink control information). For example, the trigger state of aperiodic CSI reporting can be configured as needed, and whether semi-static CSI reporting is activated can be controlled by an activation command.

[0235] For example, with respect to the configuration of a report quantity, the terminal may determine the CSI-RS port index(es) for each CSI-RS resource based on information related to a port subset per sub-configuration (hereinafter referred to as a "port subset indicator"). The port subset indicator may include a bitmap for specifying some of the antenna ports for the corresponding CSI-RS resource. Accordingly, the terminal may identify at least one antenna port for the corresponding sub-configuration based on the positions of bits set to positive values ​​(e.g., 1) in the port subset indicator.

[0236] For example, with respect to the configuration of report items (report quantity), the terminal may determine the codebook type based on the presence or absence of sub-configurations. Specifically, if sub-configurations are configured for CSI reporting, the terminal may exclude the configuration of at least one codebook type. For example, if the terminal's capabilities support it, at least one codebook type may be configured.

[0237] For example, in relation to the configuration of the report quantity, a power offset value and an NZP CSI-RS resource set may be configured for each sub-configuration. For example, depending on whether a power offset value is configured for each sub-configuration and whether an NZP CSI-RS resource set is configured, the interpretation of the NZP CSI-RS resource set for each sub-configuration may vary.

[0238] When determining the channel quality indicator (CQI), a higher-layer parameter related to time restrictions for channel measurements (e.g., timeRestrictionForChannelMeasurements) may be configured. In this case, the terminal can derive a channel estimate for determining CSI based on the most recent CSI reference resource. For example, if cell DTX is activated for the base station, the cell DTX activation time, etc., may be considered to determine the CSI reference resource, etc.

[0239] CSI is derived based on CSI reference resources. A CSI reference resource is defined as a group of downlink physical resource blocks corresponding to a band related to the CSI derived in the frequency domain, and is defined as a single downlink slot determined based on higher-layer parameters and subcarrier spacing in the time domain. After receiving a CSI-RS, a UE can transmit a CSI report no later than the CSI reference resource. For example, if sub-configurations are configured for a CSI report, a CSI reference resource may be considered for each sub-configuration.

[0240] When at least one of a CQI index, a precoding matrix index (PMI), and a rank indicator (RI) is set to be reported, in the CSI reference resource, the terminal may assume specific values ​​for the symbol positions and number occupied by control signaling, the number of PDSCH and demodulation reference signal (DMRS) symbols, the subcarrier spacing of the bandwidth part (BWP), the bandwidth for CQI reporting, the length and subcarrier spacing of the cyclic prefix (CP) of the reference resource, and the redundancy version (RV), for the purpose of deriving at least one of the CQI index, PMI, and RI. At this time, when sub-configurations are set for the CSI reporting, assumptions about the antenna port, EPRE (energy per resource element), etc. may be determined based on the sub-configurations.

[0241] Based on the aforementioned configuration, the base station can transmit at least one CSI-RS to the terminal. Based on the aforementioned configuration, the terminal can receive at least one CSI-RS and perform measurement on it. For example, the at least one CSI-RS can be transmitted via a CSI-RS resource or resource set configured by the configuration information.

[0242] When the terminal is set to DRX (discontinuous reception), the terminal can perform measurements as follows. For example, when the terminal is set to monitor power saving related control information (e.g., DCI format 2_6) and the DRX related timer (e.g., drx-onDurationTimer) has not been started by a higher layer parameter (e.g., ps-TransmitOtherPeriodicCSI), and is set to report CSI using a reporting configuration type set to periodic reporting and a reporting item set to an item other than cri-RSRP and ssb-index-RSRP, the most recent CSI measurement opportunity occurs during the time indicated by drx-onDurationTimer in the DRX related configuration information (e.g., DRX-Config) other than the DRX active time or the DRX active time for the CSI to be reported. As another example, if the terminal is configured to monitor power saving related control information (e.g., DCI format 2_6) and is configured to report L1-RSRP using a report configuration type set to periodic reporting and a report item set to cri-RSRP in a situation where drx-onDurationTimer has not started by a higher layer parameter (e.g., ps-TransmitPeriodicL1-RSRP), the most recent CSI measurement opportunity occurs during a time indicated by drx-onDurationTimer in DRX-related configuration information (e.g., DRX-Config) other than the DRX active time or the DRX active time for the CSI to be reported. In addition, the most recent CSI measurement opportunity occurs within the DRX active time for the CSI to be reported.

[0243] A base station may perform cell DTX and / or cell DRX operations. In this case, during the inactive period of cell DTX, a terminal configured as cell DTX may not expect to receive periodic CSI-RS and semi-static CSI-RS, at least as configured in a CSI reporting configuration associated with a report item including RI. When cell DTX is activated for a serving cell, the most recent CSI measurement opportunity of a semi-static CSI-RS resource or a periodic CSI-RS resource may occur within the active periods of cell DTX for CSI reporting, at least as configured by configuration information (e.g., CSI-ReportConfig) related to CSI reporting associated with a report item including RI.

[0244] A terminal that receives at least one CSI-RS can determine CSI. For example, the terminal can perform CSI calculations. The terminal can perform CSI calculations based on CSI processing criteria. The terminal can indicate the number of supported concurrent CSI calculations, for example, the number of CSI processing units (CPUs) that can be performed simultaneously, called NCPUs. The terminal can determine the number of CPUs for a given CSI report based on at least one of the NCPUs, the number of CPUs for each CSI report, the number of CPUs currently occupied, and the settings of the report items. For example, for configuration information (e.g., CSI-ReportConfig) related to CSI reporting that includes a report item parameter (e.g., reportQuantity) that is not set to 'none', the CPU(s) may be occupied for at least one orthogonal frequency division multiplexing (OFDM) symbol, wherein the number of at least one symbol may be determined based on CSI-RS resources or CSI-IM (interference measurement) resources associated with the sub-configurations.

[0245] When configuration information related to CSI reporting (e.g., CSI-ReportConfig) includes multiple sub-configurations, the number of CPUs occupied by the CSI report may be determined based on the number of CSI-RS resources corresponding to the sub-configurations. For example, the number of CSI-RS resources may be determined based on the number of times they are referred in the configuration information related to CSI reporting (e.g., CSI-ReportConfig) or the number of sub-configurations referencing the corresponding CSI-RS resources.

[0246] A terminal that has determined CSI can transmit a CSI report to a base station. The terminal can transmit CSI(s) for at least one sub-configuration according to a report item parameter (e.g., reportQuantity) configured for configuration information related to the CSI report (e.g., CSI-ReportConfig). For example, the CSI report can include at least one of PMI, CQI, RI, CRI, SSBRI (SSB resource index), LI (layer indicator), and RSRP. In this case, the CSI report can include a Part 1 CSI report and a Part 2 CSI report. In addition, the CSI report can be transmitted via at least one of a physical uplink control channel (PUCCH) or a PUSCH.

[0247] When a terminal multiplexes a CSI report including a Part 2 CSI report on a PUCCH resource, the terminal determines the number of PUCCH resources and physical resource blocks (PRBs) for the PUCCH resource or the number of Part 2 CSI reports, assuming that each CSI report or each CSI sub-report included in the CSI report indicates rank 1 or the rank combination {1, 1}. When a higher layer parameter related to the CSI reporting mode (e.g., csi-ReportMode) is set to 'Mode2', the terminal determines the PUCCH resource and the number of PRBs for the PUCCH resource or the number of Part 2 CSI reports, assuming that each CRI of the CSI report is associated with a resource pair.

[0248] When a CSI report on PUSCH includes two parts, the UE may omit some of the Part 2 CSI. The omission of Part 2 CSI is in priority order. When omitting Part 2 CSI information for a particular priority level, the UE shall exclude all information for that priority level, except when the corresponding CSI report includes at least one CSI sub-report including Part 2, which corresponds to a sub-configuration from a list of sub-configurations provided by a higher layer parameter (e.g., csi-ReportSubConfigList) included in information related to the CSI report (e.g., CSI-ReportConfig).

[0249] For a report configuration related to information related to a CSI report (e.g., CSI-ReportConfig) that includes a list of sub-configurations, the following processing is possible: For a corresponding CSI report that includes at least one CSI sub-report, omission of Part 2 CSI is performed at the sub-configuration level within the same priority level, where a sub-configuration with a lower index value has a higher priority.

[0250] If a CSI report consists of two parts, a UE may omit some of the Part 2 CSI. The omission of Part 2 CSI is based on a priority order. For a report configuration related to information related to a CSI report (e.g., CSI-ReportConfig) that includes a list of sub-configurations, for a given CSI report that includes at least one CSI sub-report, the omission of Part 2 CSI may be applied according to the CSI reporting procedure using PUSCH. Part 2 CSI may be omitted starting from the lowest priority level up to the Part 2 CSI coding rate that is less than or equal to the coding rate set by the higher layer parameter (e.g., maxCodeRate).

[0251] Additionally, if the CQI request (or CSI request) field in the DCI triggers CSI report(s) on the PUSCH, the first uplink symbol carrying the CSI report(s) may not precede a symbol specified after a certain interval from the last symbol of the PDCCH carrying the corresponding DCI. Accordingly, the CSI calculation time may be guaranteed. For example, if multiple sub-configurations are configured for the CSI report, the starting position of the aforementioned certain interval may be determined based on all triggered sub-configurations.

[0252] CSI is transmitted via PUCCH or PUSCH and can be expressed as a bit string of a fixed size. When CSI is transmitted via PUCCH, if a parameter (e.g., csi-ReportSubConfig) indicating sub-configuration-specific settings for CSI reports is configured, the mapping order of CSI fields for each CSI sub-report can be applied according to predefined rules.

[0253] When CSI is transmitted via PUSCH, if a parameter indicating sub-configuration-specific configuration for CSI reporting (e.g., csi-ReportSubConfig) is set, for each CSI sub-report, the mapping order of CSI fields can be applied according to a predefined rule.

[0254] Some or all of the examples of FIGS. 1 to 18 described above may be combined with some or all of the examples of the present disclosure described below, and such combined examples are included within the scope of the present disclosure.

[0255] Improved NES

[0256] For enhancement of NES technology, on-demand SSB, on-demand SIB1, and adaptation of common signal / channel transmissions are being discussed.

[0257] Below we describe on-demand SSB.

[0258] On-demand SSB is a NES scheme that transmits SSB when triggered in a specific cell and does not transmit SSB when not triggered. Existing NR systems require periodic, constant transmission of SSB for purposes such as time / frequency synchronization and RRM measurement, making it difficult to reduce energy consumption even when the base station has no data to receive or send. Considering this, energy consumption at the base station can be reduced by not performing SSB transmission at all and only performing SSB transmission when the on-demand SSB process is performed.

[0259] These on-demand SSB processes can be triggered by one or more of the following examples:

[0260] - The terminal requests SSB transmission from the base station by transmitting an uplink signal / channel (e.g., PRACH (physical random access channel), PUCCH, PUSCH, SRS (sounding reference signal) in the 5G NR system, and may be a signal / channel with a different name in the 6G system).

[0261] - The first base station (or TRP) requests SSB transmission from the second base station (or TRP) through an interface between base stations (e.g., Xn interface in 5G NR system, interface with different name in 6G system) or backhaul signaling, etc.

[0262] - Signaling whether SSB transmission of the corresponding SCell is possible through SCell activation / deactivation signaling.

[0263] Considering coexistence with existing NR terminals, on-demand SSB operation may be limited to connected mode terminals and SCells. In subsequent releases or next-generation communication systems, on-demand SSB operation considering inactive or idle mode terminals or initially connected terminals (e.g., on-demand SSB support on PCell) may be defined. In addition, carrier aggregation (CA) including SCells applicable to on-demand SSB may be applied to both intra-band CA and inter-band CA. SSB on SCells transmitted through on-demand SSB may be utilized at least for time / frequency synchronization, L1 / L3 measurements, SCell activation, etc.

[0264] Below, we describe On-Demand SIB1.

[0265] On-demand SIB1 corresponds to a NES scheme that transmits SIB1 when triggered on a specific cell and does not transmit SIB1 when not triggered. In the existing NR system, in order to support access to a cell by an initial access terminal or an idle mode terminal, it is required to periodically and always transmit SIB1 containing system information, random access information, etc., making it difficult to reduce energy consumption even when the base station has no data to receive or send. By allowing the base station to not perform SIB1 transmission and to perform SIB1 transmission only when the on-demand SIB1 process is performed, the energy consumption of the base station can be reduced.

[0266] This on-demand SIB1 process may include the terminal transmitting an uplink signal / channel (e.g., PRACH in a 5G NR system, or a signal / channel with a different name in a 6G system) that triggers the base station's SIB1 transmission.

[0267] FIG. 19 illustrates examples of on-demand SIB1 operations to which some examples of the present disclosure may be applied. FIG. 19 merely illustrates examples, and on-demand SIB1 operations are not limited to the examples of FIG. 19.

[0268] In (a) of FIG. 19, the terminal may receive an SSB (and / or other downlink signal / channel) from the first cell (cell#1) and recognize that SIB1 is not transmitted on the corresponding cell#1. The terminal may trigger SIB1 transmission on cell#1 by transmitting a signal requesting SIB1 (e.g., a wake-up signal (WUS)) based on information provided in the SSB (and / or other downlink signal / channel) and / or predetermined information. For example, the base station that received the WUS may transmit a specific DL signal / channel (e.g., ACK) on cell#1 in response thereto and transmit SIB1 on cell#1. Alternatively, the base station may transmit SIB1 on cell#1 without transmitting a specific DL signal / channel (e.g., ACK).

[0269] In (b) of FIG. 19, the terminal may receive an SSB (and / or other downlink signal / channel such as SIB1) from the first cell (cell#1) and recognize that SIB1 is not transmitted from the second cell (cell#2). The terminal may attempt to camp on cell#2. The terminal may trigger SIB1 transmission for cell#2 by transmitting a signal (e.g., WUS) requesting SIB1 on cell#1 based on information provided in the SSB (and / or other downlink signal / channel such as SIB1) received from cell#1 and / or predetermined information. For example, the base station receiving the WUS may transmit a specific DL signal / channel (e.g., ACK) on cell#1 (or on cell#2) in response thereto, and transmit SIB1 for cell#2 on cell#1 (or on cell#2). Alternatively, the base station may transmit SIB1 for cell#2 on cell#1 (or on cell#2) without transmitting a specific DL signal / channel (e.g., ACK).

[0270] In (c) of FIG. 19, the terminal may receive an SSB (and / or other downlink signal / channel such as SIB1) from the first cell (cell#1) and recognize that SIB1 is not transmitted from the second cell (cell#2). The terminal may attempt to camp on cell#2. The terminal may trigger SIB1 transmission for cell#2 by transmitting a signal (e.g., WUS) requesting SIB1 on cell#2 based on information provided in the SSB (and / or other downlink signal / channel such as SIB1) received from cell#1 and / or predetermined information. For example, the base station receiving the WUS may transmit a specific DL signal / channel (e.g., ACK) on cell#2 (or on cell#1) in response thereto, and transmit SIB1 for cell#2 on cell#2 (or on cell#1). Alternatively, the base station may transmit SIB1 for cell#2 on cell#2 (or on cell#1) without transmitting a specific DL signal / channel (e.g., ACK).

[0271] Below we describe the adaptation of common signal / channel transmission.

[0272] Base stations can apply NES schemes that control the transmission of common signals / channels such as SSB, PRACH, and paging. Energy consumption can be reduced more significantly when SSB is not transmitted completely but is transmitted as needed. However, if SSB that supports time / frequency synchronization or RRM measurement is not transmitted completely, stable operation of terminals for the corresponding cell may not be guaranteed. Considering this, energy saving effects of the base station can be achieved by controlling / changing the SSB transmission pattern (e.g., transmission period, period by SSB candidate index(es), SSB candidate index(es) transmitted within one transmission period, transmission power, etc.) according to the situation.

[0273] In the case of PRACH resources, in the case of contention-based random access, since the base station does not know when the terminal will transmit the PRACH, it is required to always attempt reception within the PRACH resources set for the terminal, which may increase network energy consumption. Considering this, a method for controlling the amount of PRACH resources can be applied. For example, the period of the PRACH resources can be adjusted to be longer so that the base station attempts PRACH reception less frequently. For example, the number of PRACH resources can be adjusted to be smaller, such as a method of pre-configuring PRACH resource sets #1 and #2 and activating only one of the two sets or activating both sets. For example, the amount of RACH resources corresponding to each SSB index can be provided uniformly or non-uniformly.

[0274] In the case of paging, it is defined that paging frames (PF) and / or paging occasions (PO) are distributed on the time axis within a DRX cycle (or paging cycle), and the terminal attempts to receive paging at a specific PF / PO derived from a formula based on its own identification information. If the base station wants to transmit paging to multiple terminals simultaneously, it may need to frequently transmit paging messages according to various terminal identification information values. As a method for reducing the base station energy consumption due to this, a method such as arranging the PF and / or PO as close as possible on the time axis or arranging them on distinct frequency resources within the same time resource can be applied.

[0275] Types of synchronization signals

[0276] The examples of the present disclosure assume two types of synchronization signals. While the term "SSB" is used as an example of a synchronization signal in the following description, the scope of the present disclosure is not limited by that term, and other units with different names that include synchronization signals may replace "SSB."

[0277] For example, assuming on-demand SSB on a specific cell where transmission is initiated by a base station instruction or a terminal request, Type-1 SSB and Type-2 SSB can be distinguished as follows.

[0278] Type-1 SSB may refer to an SSB transmitted periodically on a first cell or on a second cell. If a period, etc. for the SSB is determined / defined / set, the SSB may be continuously transmitted according to the period. Continuous transmission may include transmission without distinction between on and off periods for SSB transmission, or without activation or deactivation. If Type-1 SSB refers to an SSB transmitted on a first cell, the first cell may correspond to a timing reference cell. If Type-1 SSB refers to an SSB transmitted on a second cell, the second cell may be in an intra-band CA or inter-band CA relationship with the first cell. For example, (especially in an inter-band CA environment) the second cell may be set as a timing reference cell for the first cell, or (in an intra-band CA environment) the second cell may be determined / defined as a timing reference cell for the first cell (e.g., a specific cell within the same timing advance group or a PCell or PSCell (primary secondary cell, i.e., a primary cell within a secondary cell group (SCG)). Also, only Type-2 SSBs may be transmitted on a specific cell without Type-1 SSBs.

[0279] Type-2 SSB may refer to an SSB in which transmission on a specific cell is activated through a configuration / instruction of the base station (via RRC / MAC-CE / DCI, etc.) or upon a request of the terminal. For an activated SSB, SSB deactivation may be explicitly configured / instructed via RRC / MAC-CE / DCI, etc. Alternatively, for an SSB in which the number of transmissions or transmission intervals are configured / instructed in the RRC / MAC-CE / DCI instructing SSB activation, the SSB may be deactivated when the corresponding number of transmissions or transmission intervals have expired. Alternatively, if there is a pre-configured / defined number of transmissions or transmission intervals, the SSB may be deactivated when the corresponding number of transmissions or transmission intervals have expired after SSB activation. Alternatively, (if a specific cell is an SCell) the SSB may be deactivated when activation for the specific cell is completed (or when CSI reporting for the specific cell is successfully completed). Alternatively, SSB may be deactivated when the specific cell is deactivated (if the specific cell is an SCell). Alternatively, SSB may be deactivated after a handover from the specific cell to another cell (if the specific cell is a PCell). Alternatively, SSB may be deactivated at the request of the UE.

[0280] As another example, it can be assumed that one or more SSB configurations are configured among different SSB configurations with at least different SSB cycle values, and an SSB corresponding to one of the SSB configurations is transmitted at the base station's instruction or the terminal's request. In this case, adaptation to the SSB cycle can be performed by varying the activated SSB configuration. In this case, Type-1 SSB and Type-2 SSB can be distinguished as follows.

[0281] Type-1 SSB may refer to a reference SSB setting among the configured SSB setting(s). For example, the reference SSB setting may correspond to the SSB setting having the largest SSB period value. For example, if an SSB setting corresponding to a Type-2 SSB is not activated, an SSB setting corresponding to a Type-1 SSB may be activated. Alternatively, if an SSB setting corresponding to a Type-2 SSB is activated, an SSB setting corresponding to a Type-1 SSB may be deactivated. Alternatively, if SSB opportunities specified based on a particular SSB setting (e.g., the reference SSB setting) among the configured SSB settings are a subset of SSB opportunities specified based on other SSB settings (e.g., "extended SSB opportunities"), the reference SSB opportunities may be defined as a Type-1 SSB (regardless of the actual activated SSB setting). In this case, Type-2 SSB can be defined as the remaining SSB opportunities among the extended SSB opportunities (included in the actual activated SSB configuration) excluding the reference SSB opportunities.

[0282] For Type-2 SSB, in addition to the SSB configuration corresponding to Type-1 SSB, one or more SSB configurations for Type-2 SSB can be configured. When an SSB configuration corresponding to Type-2 SSB is activated, all SSBs belonging to the activated SSB configuration can be defined as Type-2 SSBs. Alternatively, if SSB opportunities configured based on a specific SSB configuration (e.g., a reference SSB configuration) among the configured SSB configurations (hereinafter, referred to as "reference SSB opportunities" for convenience) are a subset of SSB opportunities configured based on other configurations (hereinafter, referred to as "extended SSB opportunities" for convenience), the reference SSB opportunities can be defined as Type-1 SSBs (regardless of the actual activated SSB configuration), in which case Type-2 SSBs can be defined as the remaining SSB opportunities among the extended SSB opportunities (in the actual activated configuration) excluding the reference SSB opportunities. One or more SSB configurations may be activated by a configuration / instruction (via RRC / MAC-CE / DCI) of the base station or by a request of the terminal. For an activated SSB configuration, SSB deactivation may be explicitly configured / instructed via RRC / MAC-CE / DCI, etc. Alternatively, for an SSB activated by configuring / instructing the number of transmissions or transmission intervals in the RRC / MAC-CE / DCI instructing the activation of the SSB configuration, when the corresponding number of transmissions or transmission intervals expire, the SSB may be deactivated. Alternatively, if there is a pre-configured / defined number of transmissions or transmission intervals, the SSB may be deactivated when the corresponding number of transmissions or transmission intervals expire after the SSB is activated. Alternatively, (if a specific cell is an SCell) the SSB may be deactivated when activation for the specific cell is completed (or CSI reporting for the specific cell is successfully completed). Alternatively, (if a specific cell is an SCell) the SSB may be deactivated when the specific cell is deactivated.Alternatively, SSB may be deactivated after a handover from a specific cell to another cell (if the specific cell is a PCell). Alternatively, SSB may be deactivated at the request of the terminal.

[0283] As another example, it can be assumed that one or more SSB configurations are configured and an SSB corresponding to one of the SSB configuration(s) is transmitted at the instruction of the base station or upon the request of the terminal. In this case, there is an SSB (e.g., Type-1 SSB) that continues to be transmitted periodically regardless of the activation / deactivation of the corresponding SSB configuration(s), and an SSB configuration to be transmitted in addition to this SSB can be activated / deactivated. At least the SSB period value or SSB time pattern can be different between different SSB configurations. In this case, adaptation to the SSB period can be performed by varying the activated SSB configuration. In this case, Type-1 SSB and Type-2 SSB can be distinguished as follows.

[0284] Type-1 SSB may mean an SSB corresponding to the default SSB setting, and continuous periodic transmission may be guaranteed for Type-1 SSB regardless of the activation / deactivation of the SSB setting(s) corresponding to Type-2 SSB.

[0285] One or more SSB configurations for Type-2 SSB can be configured. One of the one or more SSB configurations can be activated by a configuration / instruction from a base station (via RRC / MAC-CE / DCI) or a request from a terminal. For an activated SSB configuration, SSB deactivation can be explicitly configured / instructed via RRC / MAC-CE / DCI, etc. Alternatively, for an SSB activated by configuring / instructing the number of transmissions or transmission intervals in the RRC / MAC-CE / DCI indicating the activation of the SSB configuration, when the number of transmissions or transmission intervals has expired, the SSB can be deactivated. Alternatively, if there is a pre-configured / defined number of transmissions or transmission intervals, the SSB can be deactivated when the number of transmissions or transmission intervals has expired after the SSB is activated. Alternatively, the SSB can be deactivated when activation for the specific cell is completed (or when CSI reporting for the specific cell is successfully completed) (if the specific cell is an SCell). Alternatively, SSB may be deactivated when the specific cell is deactivated (if the specific cell is an SCell). Alternatively, SSB may be deactivated after a handover from the specific cell to another cell (if the specific cell is a PCell). Alternatively, SSB may be deactivated at the request of the UE.

[0286] In the various examples described above, Type-1 SSB may correspond to an SSB that can assume continuous periodic transmission, and Type-2 SSB may correspond to an SSB that cannot assume continuous periodic transmission. In some of the examples described below, the always-on SSB may correspond to or be replaced by the Type-1 SSB described above, and the on-demand SSB may correspond to or be replaced by the Type-2 SSB described above.

[0287] Transmission and reception of various synchronization signals during the initial access process

[0288] This disclosure describes various examples for improving SSB transmission related to NES in 6G systems. Although the structure and features of SSB (i.e., SS / PBCH block) as in 5G systems are not directly applicable in 6G systems, the term "SSB" described in this disclosure may be replaced with a group of synchronization signals or a group including a synchronization signal and other physical signals / channels, and the term "SSB" is used for convenience of explanation.

[0289] As mentioned above, the SSB can be operated by the base station by distinguishing it into the first SSB (or SSB1, AO SSB, etc.) and the second SSB (or SSB2, OD SSB, etc.). SSB1 can be defined as an SSB that the base station transmits constantly or periodically. SSB2 can be defined as an SSB that the base station transmits or does not transmit depending on the situation. The base station can transmit SSB1 minimally and additionally transmit SSB2 when necessary. For example, in order to minimize the energy consumption of the base station, the base station can transmit SSBs corresponding to SSB1, and then additionally transmit SSB2 when there is internal energy left (or when SSB transmission with a relatively shorter period than the SSB1 period is required). The terminal can perform the initial access through SSB1 or SSB2. For example, when the terminal generally switches from power-off to power-on, the terminal can determine whether the cell to be accessed is accessible and whether it is barred through a combination of received SSBs. In this case, the terminal may need to know whether the SSB detected / received is SSB1 or SSB2.

[0290] The present disclosure describes a method for a base station to inform a terminal of which SSB the terminal is receiving through an initial access process in which the terminal receives a synchronization signal (e.g., PSS, SSS) and broadcast information (e.g., MIB provided via PBCH), and a method for the terminal to recognize information about such SSB.

[0291] For example, a terminal attempting initial access to a cell does not know precisely whether to transmit or transmit SSBs that are always transmitted (e.g., SSB1 transmitted at a long cycle) and SSBs that may vary in transmission for purposes such as energy saving (e.g., SSB2 transmitted at a short cycle), or the transmission cycle, and does not know the SSB measurement time configuration (SMTC). In this situation, the present disclosure describes various methods for enabling the terminal to distinguish whether the SSB it is receiving during the synchronization process is SSB1 or SSB2. In the present disclosure, the SSB is not limited to an OD SSB for NES purposes, and should be understood as an extended concept that includes an SSB to which time domain adaptive transmission can be applied.

[0292] As described above, the term SSB may refer to a group of signals / channels involved in the process of obtaining the most basic information of a cell through system information (e.g., checking information of contents or bit fields through decoding of MIB / PBCH) after a terminal finds an OFDM symbol boundary through a primary synchronization signal (e.g., PSS detection), finds cell identification information through a secondary synchronization signal (e.g., SSS detection), and then the system information. The primary synchronization signal, secondary synchronization signal, and system information included in the synchronization signal group may be transmitted in continuous time resources or may be transmitted discontinuously (e.g., at time intervals, or at different cycles). For example, all three elements (e.g., PSS, SSS, and PBCH) may be transmitted at each SSB transmission opportunity, or some combination of the three elements (e.g., only PSS, or a combination of PSS and PBCH, or PSS and SSS, etc.) may be transmitted at some transmission opportunities. For example, by predefining specific instructions or signaling information for three elements, a terminal can determine whether an SSB corresponds to SSB1 or SSB2. If all three elements are transmitted, it corresponds to SSB1, and if some are transmitted, it corresponds to SSB2.

[0293] Here, elements within SSB may be referred to in various ways, such as signal / channel / information / part, etc.

[0294] FIG. 20 is a diagram showing examples of various SSB transmissions to which the present disclosure can be applied.

[0295] Figure 20(a) exemplarily illustrates the transmission opportunities for SSB1 and SSB2. SSB1 can be transmitted at relatively long intervals, while SSB2 can be transmitted at relatively short intervals. SSB1 is always transmitted, while SSB2 may or may not be transmitted at any given transmission opportunity.

[0296] As shown in Figure 20(b), the elements of the SSB transmitted in different SSB2 transmission opportunities may not be identical. For example, in one SSB2 transmission opportunity, the PSS, SSS, and PBCH may all be transmitted. In another SSB2 transmission opportunity, only the PSS and SSS may be transmitted. In another SSB2 transmission opportunity, only the PSS may be transmitted. In another SSB2 transmission opportunity, only the SSS may be transmitted. The elements included in the SSB may be explicitly or implicitly indicated / signaled.

[0297] For example, different combinations of elements included in an SSB may be applied to different services / purposes. Accordingly, two or more SSBs may be defined and referred to, for example, as SSBn (n=1, 2, 3, ...).

[0298] Different SSBs (e.g., SSB1 and SSB2) may exist in the same frequency location (e.g., bandwidth / band), but may be distinguished by different sets / orders of REs to which they are mapped, or by the order in which the elements of the SSB are mapped.

[0299] When a base station operates at low power for purposes such as NES, a method for distinguishing different SSBn may be required. For example, different SSBn can be distinguished using the existing PSS and SSS. PSS and SSS can be detected and received by finding the sequence by attempting to decode the sequence in a trial and error manner using a sequence correlator, rather than by decoding the channel based on the reference signal. Therefore, through PSS and SSS, the UE can not only identify the existing cell but also determine whether the SSB is an AO SSB or an OD SSB. If PSS and SSS are used for synchronization and cell identification as before, the UE can use the bit field information in the PBCH to distinguish the SSB. Alternatively, a short sample sequence can be added and decoded to distinguish whether the SSB is an AO SSB or an OD SSB. Furthermore, SSB1, SSB2, SSB3, ... can be distinguished by service, and in this case, various methods for distinguishing SSBs from each other can be applied.

[0300] In the examples of the present disclosure, even if the first SSB and the second SSB are not transmitted in the same PRB region, if they are transmitted within the range of the bandwidth that the terminal can detect / receive at one time, the center frequency of the first SSB and the center frequency of the second SSB may not exactly match. The examples below mainly describe a method in which various SSBs are utilized in the process of attaching to a cell by attempting an initial access after the terminal is switched from power-off to power-on.

[0301] FIG. 21 is a drawing for explaining an example of a method performed by a terminal according to the present disclosure.

[0302] In step S2110, the terminal can receive a first synchronization signal group and a second synchronization signal group from a first frequency resource.

[0303] In some examples, the first frequency resource may be distinguished from a second frequency resource on which the first synchronization signal group is transmitted and on which the second synchronization signal group is not transmitted.

[0304] For example, one or more candidates of the first frequency resource and one or more candidates of the second frequency resource can be predefined as synchronization rasters.

[0305] For example, the location of one or more candidates of the first frequency resource may be defined as a location spaced apart by a specific offset from the location of one or more candidates of the second frequency resource.

[0306] For example, one or more candidates for the second frequency resource and one or more candidates for the first frequency resource may be positioned alternately in the frequency domain.

[0307] In step S2120, the terminal may perform measurement based on the first synchronization signal group and the second synchronization signal group based on the second synchronization signal group being received from the first frequency resource.

[0308] Based on the measurement results based on the first synchronization signal group and the second synchronization signal group of a cell, the terminal can determine whether to transmit a signal (e.g., transmit a random access preamble) for initial access to the cell.

[0309] In some examples, the first synchronization signal group and the second synchronization signal group may be distinguished based on the sequence group. In other examples, the first synchronization signal group and the second synchronization signal group may be distinguished based on information included in each of the first synchronization signal group and the second synchronization signal group. In still other examples, the first synchronization signal group and the second synchronization signal group may be distinguished based on the sequence group and information included in each of the first synchronization signal group and the second synchronization signal group.

[0310] In some examples, the first sequence group may include one or more sequence candidates mapped to the first synchronization signal group. The second sequence group may include one or more sequence candidates mapped to the second synchronization signal group. The sequence candidates may be candidates for sequences associated with the first synchronization signal (e.g., PSS). Alternatively, the sequence candidates may be candidates for sequences associated with the second synchronization signal (e.g., SSS). Alternatively, the sequence candidates may be candidates for sequences associated with a demodulation reference signal (e.g., DMRS of a PBCH including system information). Alternatively, the sequence candidates may be candidates for sequences associated with a combination of two or more of the first synchronization signal, the second synchronization signal, or the demodulation reference signal.

[0311] In some examples, the first synchronization signal group may be transmitted based on the first synchronization signal group period, and the second synchronization signal group may be transmitted based on the second synchronization signal group period. In this case, different sequence groups may correspond to different synchronization signal group periods.

[0312] In some examples, the first sequence group may correspond to one or more elements of the first group included in the second synchronization signal group, and the second sequence group may correspond to one or more elements of the second group included in the second synchronization signal group. The one or more elements that may be included in the synchronization signal group may correspond to the first synchronization signal, the second synchronization signal, and / or system information. For example, the elements of the first group may include the first synchronization signal, the second synchronization signal, and system information. For example, the elements of the second group may include the first synchronization signal and the second synchronization signal.

[0313] In some examples, information included in the first synchronization signal group may be included in system information within the first synchronization signal group. Information included in the second synchronization signal group may be included in system information within the second synchronization signal group.

[0314] In some examples, the information included in the first synchronization signal group may be a first system frame number (SFN), and the information included in the second synchronization signal group may be a second SFN. In this case, the first synchronization signal group and the second synchronization signal group may be distinguished based on the result of the modulo operation for the first SFN and the result of the modulo operation for the second SFN.

[0315] In some examples, the information included in the first synchronization signal group may include information about the period or transmission status of the second synchronization signal group. The information included in the second synchronization signal group may include information about the period or transmission time of the next synchronization signal group.

[0316] In some examples, the number and / or locations of physical resources (e.g., time resources and / or frequency resources) to which information included in the first synchronization signal group is mapped may be distinct from the number and / or locations of physical resources to which information included in the first synchronization signal group is mapped.

[0317] In some examples, the information included in the second synchronization signal group may be set to a value indicating the second synchronization signal group. The information indicating the first synchronization signal group may be undefined.

[0318] In some examples, information included in the first synchronization signal group may be set to a value indicating the first synchronization signal group, and information included in the second synchronization signal group may be set to a value indicating the second synchronization signal group.

[0319] In some examples, the first system information included in the first synchronization signal group and the second system information included in the second synchronization signal group may be distinguished based on content, mapping location, whether some content is included, and / or period.

[0320] In some examples, each of the first synchronization signal group and the second synchronization signal group may include an additional sequence that distinguishes the first synchronization signal group and the second synchronization signal group. For example, the additional sequence may be mapped to an unused PRB of the corresponding synchronization signal group.

[0321] In some examples, different periods may be predefined for the first synchronization signal group and the second synchronization signal group. Accordingly, based on the results of the periodic reception of the synchronization signal group detected by the terminal, it can be determined whether the synchronization signal group corresponds to the first or second synchronization signal group.

[0322] In some examples, a first synchronization signal group may correspond to one or more elements of a first location (e.g., a first synchronization signal, a second synchronization signal, and / or system information), and a second synchronization signal group may correspond to one or more elements of a second location. The first location may correspond to a first order of elements in time and / or frequency location, and the second location may correspond to a second order of elements in time and / or frequency location.

[0323] In some examples, the first synchronization signal group may include system information and the second synchronization signal group may not include system information.

[0324] In some examples, the third synchronization signal group may include information about a first frequency range (e.g., a frequency range in which the first synchronization signal group and the second synchronization signal group can transmit) and a second frequency range (e.g., a frequency range in which the second synchronization signal group is not transmitted and the first synchronization signal group is transmittable). For example, the third synchronization signal group may correspond to a non-cell defining synchronization signal group.

[0325] In some examples, the second synchronization signal group may be transmitted based on the on-demand SSB configuration. The first synchronization signal group may correspond to SSB that is always transmitted periodically.

[0326] The method described in the example of FIG. 21 may be performed by the wireless device (200) of FIG. 3 corresponding to the first node (110) of FIG. 2 described above. For example, one or more processors (202) of the wireless device (200) of FIG. 3 may be configured to receive one or more first synchronization signal groups and one or more second synchronization signal groups through the transceiver (206) in the first frequency resource, and perform measurements based on the first synchronization signal group and the second synchronization signal group based on the second synchronization signal group being received in the first frequency resource. Furthermore, one or more memories (204) of the wireless device (200) may store commands for performing the method described in the example of FIG. 21 or the examples described below when executed by one or more processors (202).

[0327] FIG. 22 is a drawing illustrating an example of a method performed by a base station according to the present disclosure.

[0328] In step S2210, the base station can transmit a first synchronization signal group and a second synchronization signal group to one or more terminals in a first frequency resource.

[0329] In some examples, the first frequency resource may be distinguished from a second frequency resource on which the first synchronization signal group is transmitted and on which the second synchronization signal group is not transmitted.

[0330] In step S2220, the base station may receive an initial access signal (e.g., a random access preamble) from the first terminal based on measurements based on the first synchronization signal group and the second synchronization signal group of the first terminal among one or more terminals.

[0331] In the example of Fig. 22, specific features related to the first synchronization signal group, the second synchronization signal group, the first frequency domain, the second frequency domain, the sequence group, and the information included in the synchronization signal group are the same as those described with reference to the example of Fig. 21, and therefore, redundant descriptions are omitted.

[0332] The method described in the example of FIG. 22 may be performed by the wireless device (200) of FIG. 3 corresponding to the second node (120) of FIG. 2 described above. For example, one or more processors (202) of the wireless device (200) of FIG. 3 may be configured to transmit a first synchronization signal group and a second synchronization signal group to one or more terminals through one or more transceivers (206) in a first frequency resource, and receive an initial access signal from the first terminal through one or more transceivers (206) based on a measurement based on the first synchronization signal group and the second synchronization signal group of the first terminal among the one or more terminals. Furthermore, one or more memories (204) of the wireless device (200) may store instructions for performing the method described in the example of FIG. 22 or the examples described below when executed by one or more processors (202).

[0333] In the examples of FIGS. 21 and 22, the first synchronization signal group may correspond to (AO) SSB, and the second synchronization signal group may correspond to OD SSB.

[0334] Hereinafter, more specific examples of the present disclosure will be described regarding a method for transmitting various synchronization signals during an initial access process and a method for a terminal to distinguish and receive them. In the examples below, the terms SSB1 and SSB2 are used for clarity, but an SSB corresponds to a group of synchronization signals including one or more synchronization signals and / or system information (broadcast information) of any structure, and the number of SSBs is not limited to two, and the examples below can also be applied to three or more SSBs.

[0335] Example 1

[0336] This embodiment is for frequency resources for SSB1 and SSB2.

[0337] In a 4G LTE wireless communication system, a terminal that has been powered on from a power-off state can search for a center frequency through a frequency scan and attempt to detect a synchronization signal based on the center frequency. In a 5G NR wireless communication system, blind detection of SSB can be attempted by scanning frequency positions where SSB can be transmitted (e.g., Global Synchronization Channel Number (GSCN) assigned to frequency positions at predetermined intervals in a synchronization raster). Although there is only one center frequency in a frequency band, the center frequencies of candidate SSBs corresponding to GSCN values ​​can exist in multiple positions other than the center frequency of a specific frequency band. The base station can transmit SSB on a frequency resource defined at one or more of the candidate SSB center frequencies. For example, SSBs corresponding to multiple GSCNs may be transmitted, and the period or structure of SSBs transmitted on different frequency resources may be the same as defined in 5G NR, and in some cases, the subcarrier spacing (SCS) may be different.

[0338] In the present disclosure, the locations of candidate frequency resources where SSB1 can be transmitted and the locations of candidate frequency resources where both SSB1 and SSB2 can be transmitted can be distinguished. The candidate frequency resource locations can correspond to frequency locations at predetermined intervals in the synchronization raster.

[0339] When attempting to detect an SSB based on a synchronization raster corresponding to candidate frequency resources on which an SSB can be transmitted, the frequency resources on the synchronization raster may be distinguished according to service. For example, depending on the location of the frequency resource in which the SSB is detected among a plurality of candidate frequency resources (e.g., candidate frequency resources corresponding to the synchronization raster) within a specific frequency band, the terminal can determine which type of service-related information the base station is transmitting. For example, assuming a base station providing an NES service and a general service, if an SSB is detected in the first candidate frequency resource (or the first synchronization raster), the NES service is being provided, and if an SSB is detected in the second candidate frequency resource (or the second synchronization raster), the general service is being provided. This can be implicitly indicated to the terminal without separate signaling. In this way, depending on the location on the synchronization raster of the frequency resource where the SSB is detected / received, the mode / service supported by the base station transmitting the SSB can be indicated to the terminal.

[0340] Example 1-1

[0341] The locations of frequency resources that can transmit only SSB1 (e.g., not SSB2) and the locations of frequency resources that can transmit both SSB1 and SSB2 can be defined distinctly. The locations of frequency resources can correspond to locations on the synchronization raster.

[0342] For example, a location separated by a specific frequency offset from the synchronization raster location of a second frequency resource capable of transmitting only SSB1 can be defined as the location of a first frequency resource capable of transmitting both SSB1 and SSB2.

[0343] For example, the result of adding the offset values ​​to the positions of candidates for the second frequency resource can be calculated as the positions of candidates for the first frequency resource.

[0344] Example 1-2

[0345] Among all frequency resource locations where SSB1 can be transmitted (e.g., frequency resource locations where SSB can be transmitted in an existing synchronization raster), some location(s) may be defined as frequency resource locations where both SSB1 and SSB2 can be transmitted. The remaining location(s) may be defined as frequency resource locations where only SSB1 can be transmitted.

[0346] For example, among all frequency resource positions where SSB1 can transmit, even-numbered positions can be defined as frequency resource positions where only SSB1 can transmit, and odd-numbered positions can be defined as frequency resource positions where both SSB1 and SSB2 can transmit.

[0347] For example, among all frequency resource locations where SSB1 can transmit, odd-numbered locations can be defined as frequency resource locations where only SSB1 can transmit, and even-numbered locations can be defined as frequency resource locations where both SSB1 and SSB2 can transmit.

[0348] FIG. 23 is a diagram illustrating examples of various SSB transmissions at different frequency resource locations according to the present disclosure.

[0349] For example, in the first frequency resource (or the frequency resource centered on the first synchronization raster), both SSB1 and SSB2 may be transmitted. SSB2 may not be transmitted in all transmission opportunities shown, or may be transmitted only in some transmission opportunities in an on / off manner. In the second frequency resource (or the frequency resource centered on the second synchronization raster), only SSB1 may be transmitted, and SSB2 may not be transmitted.

[0350] During the initial access process, the terminal may attempt to detect an SSB for the first or second frequency resource on the first or second synchronization raster. If an SSB is detected on the second frequency resource on the second synchronization raster, the terminal may receive the SSB assuming that SSB1 is transmitted periodically and SSB2 is not transmitted. If an SSB is detected on the first frequency resource on the first synchronization raster, SSB1 and SSB2 may be received with distinction based on various examples described below. By receiving SSB1 and SSB2 with distinction, the terminal can clearly know which SSB among SSB1 or SSB2 will be transmitted with which period in a subsequent SSB transmission opportunity, and thus can correctly receive the corresponding SSB. If the terminal cannot distinguish whether the detected SSB is SSB1 or SSB2, it cannot clearly know whether there will be an SSB transmission or which SSB will be transmitted in a subsequent SSB transmission opportunity.

[0351] Example 2

[0352] This embodiment relates to a method for distinguishing between SSB1 and SSB2 based on sequence groups.

[0353] During the terminal's initial access process, PSS can be detected based on a synchronization raster, and then SSS detection can be attempted. Unlike the decoding process for information transmission via channel coding, sequence-based information transmission, such as a synchronization signal, can be interpreted as having been transmitted based on which sequence among predetermined sequence candidates has the highest correlation.

[0354] When a frequency resource location where SSB1 and SSB2 can be transmitted is determined and a terminal attempts to detect an SSB at that location, a sequence or sequence group included in the SSB can be used to distinguish whether the detected SSB is SSB1 or SSB2.

[0355] Example 2-1

[0356] Assuming that N sequence candidates are defined for the sequences included in the existing SSB (e.g., PSS, SSS, and / or PBCH DMRS), 2*N sequence candidates can be defined to distinguish between SSB1 and SSB2. For example, among the 2*N sequence candidates, a group of N sequence candidate(s) can correspond to SSB1, and the remaining group of N sequence candidate(s) can correspond to SSB2.

[0357] For example, three sequence candidates can be defined for a PSS included in an existing SSB. In order to distinguish between SSB1 and SSB2, a total of 6 (=2*3) sequence candidates can be defined by additionally considering the state applied to SSB1 (e.g., state value 0) and the state applied to SSB2 (e.g., state value 1) in addition to the existing three sequence candidates.

[0358] For example, 336 sequence candidates (or sequence patterns) can be defined for SSS included in the existing SSB. In order to distinguish between SSB1 and SSB2, a total of 672 (=2*336) sequence candidates can be defined by additionally considering the state applied to SSB1 (e.g., state value 0) and the state applied to SSB2 (e.g., state value 1) in addition to the existing 336 sequence candidates. If it is assumed that the number of sequence candidates for SSS is 350, 700 sequence candidates can be defined to distinguish between SSB1 and SSB2.

[0359] For example, eight sequence candidates can be defined for PBCH DMRS included in the existing SSB. In order to distinguish between SSB1 and SSB2, a total of 16 (=2*8) sequence candidates can be defined by additionally considering the state applied to SSB1 (e.g., state value 0) and the state applied to SSB2 (e.g., state value 1) in addition to the existing eight sequence candidates.

[0360] In the process of detecting a signal of a specific sequence, the terminal can check whether the base station applied a state value of 0 or 1 to distinguish between SSB1 and SSB2 among several variables in the process of generating the sequence. Accordingly, if a sequence generated assuming that the state value is 0 is detected, it can be determined that the detected SSB is SSB1, and if a sequence generated assuming that the state value is 1 is detected, it can be determined that the detected SSB is SSB2.

[0361] In order to prevent a decrease in detection performance when the number of sequence candidates to be detected by the terminal increases, on a first frequency resource where both SSB1 and SSB2 can be transmitted, SSB may be transmitted at a higher power than on a second frequency resource where only SSB1 can be transmitted.

[0362] Example 2-2

[0363] Assuming that N sequence candidates are defined for sequences included in the existing SSB (e.g., PSS, SSS, and / or PBCH DMRS), SSB1 and SSB2 can be distinguished based on the N sequence candidates. For example, among the N sequence candidates, some groups of sequence candidate(s) can correspond to SSB1, and some groups of sequence candidate(s) can correspond to SSB2.

[0364] For example, three sequence candidates can be defined for a PSS included in an existing SSB. The 0th and 1st sequence candidates are defined to correspond to SSB1, and the 2nd sequence candidate is defined to correspond to SSB2, so that SSB1 and SSB2 can be distinguished.

[0365] Similarly, some of the sequence candidates for SSS can be defined as corresponding to SSB1 and others as corresponding to SSB2. Some of the PBCH DMRS sequence candidates can be defined as corresponding to SSB1 and others as corresponding to SSB2.

[0366] Furthermore, rather than being limited to distinguishing between two sequence groups, the entire set of sequence candidates can be divided into n (= 1, 2, 3, ...) groups, each of which can be defined as corresponding to SSBn. Accordingly, the detected SSB can be distinguished as corresponding to SSBn based on whether a sequence corresponding to the n-th sequence candidate group is detected.

[0367] A group ID may be predefined for a group of sequence candidate(s). For example, the nth SSB corresponding to the group ID to which the detected sequence belongs may be determined.

[0368] Example 2-3

[0369] Sequence candidates can be divided into K groups, and each of the K groups can be mapped to K SSB periods. Accordingly, the period of the detected SSB can be implicitly indicated to the terminal based on the sequence group to which the detected sequence belongs.

[0370] The period of an SSB may be additionally indicated by the type of SSB. For example, the period of an SSB1 or an SSB2 may be indicated simultaneously with the sequence candidate group indicating whether it is an SSB1 or an SSB2.

[0371] For example, three sequence candidates can be defined for a PSS included in an existing SSB. For example, the 0th sequence candidate can be defined to correspond to an SSB period of 10 ms, the 1st sequence candidate can be defined to correspond to an SSB period of 20 ms, and the 2nd sequence candidate can be defined to correspond to an SSB period of 80 ms.

[0372] For example, 336 sequence candidates can be defined for SSS included in the existing SSB. For example, even-numbered sequence candidates can be defined to correspond to an SSB period of 40 ms, and odd-numbered sequence candidates can be defined to correspond to an SSB period of 80 ms.

[0373] Similarly, for PBCH DMRS, the kth (=1, 2, 3, ...) sequence candidate group can be defined as corresponding to the kth SSB period.

[0374] In the method of defining 2*N sequence candidates in the aforementioned embodiment 2-1, the 2*N sequence candidates can be divided into K sequence candidate groups and defined in advance to be mapped to K SSB periods.

[0375] In addition to dividing the sequence candidates to distinguish between SSB1 and SSB2 in the aforementioned embodiment 2-2, the sequence candidate groups can also be defined by subdividing them by period. For example, among the eight PBCH DMRS sequence candidates, even-numbered sequence candidates can be defined to correspond to SSB1, and odd-numbered sequence candidates can be defined to correspond to SSB2. Additionally, the 0th and 2nd sequence candidates can be defined to correspond to an SSB period of 20 ms, the 4th and 6th sequence candidates can be defined to correspond to an SSB period of 40 ms, the 1st and 3rd sequence candidates can be defined to correspond to an SSB period of 20 ms, and the 5th and 7th sequence candidates can be defined to correspond to an SSB period of 40 ms.

[0376] In this embodiment, the terminal can distinguish between SSB1 and SSB2 based on which sequence candidate group the detected sequence belongs to, and additionally determine the cycle of the corresponding SSB. Alternatively, the terminal can determine the cycle of the SSB based on which sequence candidate group it belongs to, without distinguishing between SSB1 and SSB2.

[0377] Example 2-4

[0378] The present embodiment relates to a method for indicating a combination of elements included in SSB2 (e.g., a first synchronization signal (e.g., PSS), a second synchronization signal (e.g., SSS), system information (e.g., PBCH)) based on a sequence candidate group.

[0379] For example, the N sequence candidates of PSS transmitted in SSB2 can each be mapped to different combinations of elements (e.g., PSS, SSS, PBCH).

[0380] For example, as described with reference to FIG. 20(b), all of the elements included in SSB2 may or may not be transmitted, and some of the elements included in SSB2 (e.g., PSS, SSS, PBCH) may or may not be transmitted.

[0381] For example, assuming that there are 6 sequence candidates for PSS, the odd-numbered sequence candidate can be defined as corresponding to SSB1, and the even-numbered sequence candidate can be defined as corresponding to SSB2. More specifically, the 0th sequence candidate can be defined as corresponding to SSB2 where PSS, SSS, and PBCH are all transmitted, the 2nd sequence candidate can be defined as corresponding to SSB2 where PSS and SSS are transmitted, and the 4th sequence candidate can be defined as corresponding to SSB2 where only PSS is transmitted. Accordingly, depending on which sequence candidate the PSS sequence of the SSB detected by the terminal corresponds to, the terminal can clearly determine whether the SSS and PBCH are transmitted in the corresponding SSB.

[0382] According to the examples described above, the terminal can clearly determine whether the detected SSB is SSB1 or SSB2 depending on which sequence candidate group the PSS / SSS / PBCH DMRS sequence included in the SSB corresponds to during the initial access process. For example, if the detected SSB corresponds to SSB1, the terminal can assume that SSB1 will also be transmitted in the next (for SSB1) cycle. Alternatively, if the detected SSB corresponds to SSB2, the terminal can know that the SSB transmission in the next cycle is uncertain (for example, the base station may turn off the transmission of SSB2). Furthermore, the terminal can clearly determine the cycle of the detected SSB depending on which sequence candidate group the detected sequence corresponds to. For example, if the cycle of the detected SSB is confirmed to be P, the terminal can expect that the corresponding SSB will be transmitted after time P.

[0383] Example 3

[0384] This embodiment relates to a method for including SSB-related information in system information (e.g., PBCH / MIB) included in SSB.

[0385] The MIB or PBCH payload information of the PBCH may generally include the minimum essential information that the UE needs to know about the cell prior to receiving the SIB. After decoding the PBCH / MIB via the PBCH DMRS, the UE can determine whether the SSB is SSB1 or SSB2. For example, if the value of a specific bit position in the PBCH bit field is 0, it may correspond to SSB1, and if the value is 1, it may correspond to SSB2. In addition, various examples of including SSB-related information in the system information within the SSB are described below.

[0386] Example 3-1

[0387] After decoding the MIB / PBCH, the terminal can obtain information on the system frame number (SFN). Based on the result of the modulo operation on the SFN value, the terminal can determine whether the corresponding SSB is SSB1 or SSB2. For example, if the result of the SFN modulo P operation is 0, it can be determined as SSB1, and if it is any value other than 0, it can be determined as SSB2. This P value can be defined in advance. This example may correspond to a case where a restriction is applied that SSB1 is transmitted only in frames where the result of the SFN modulo P operation is a specific value (e.g., 0).

[0388] Accordingly, whether it is SSB1 or SSB2 can be indicated without adding a bit field to the system information within the SSB.

[0389] Example 3-2

[0390] The PBCH / MIB may contain information about the periodicity of specific SSBs.

[0391] The period of SSB1 or whether SSB2 is transmitted between periodic transmissions of SSB1 can be indicated through the PBCH / MIB included in SSB1.

[0392] The transmission / reception time of the earliest SSB1 or SSB2 following the SSB2 can be implicitly or explicitly indicated through the PBCH / MIB included in the SSB2.

[0393] Example 3-3

[0394] There may be differences between the contents of the PBCH / MIB included in SSB1 and some of the contents of the PBCH / MIB included in SSB2. Accordingly, the time-frequency resource sizes and / or locations (e.g., the number of PRBs, locations, the number of OFDM symbols, locations, the number of REs, locations, etc.) to which the PBCH / MIBs included in different SSBs are mapped may differ.

[0395] These differences can be notified to the terminal in advance, such as through sequence detection, before PBCH / MIB decoding. Alternatively, these differences can be predefined without indicating / signaling to the terminal.

[0396] Example 3-4

[0397] When the transmission period of SSB2 is indicated based on the information included in SSB1, it is possible to indicate to the terminal that the SSB is SSB2 through a specific value of the bit field of PBCH / MIB included in SSB2.

[0398] For example, if the value of a bit at a specific position in the bit field of PBCH / MIB included in SSB2 is 0, the terminal can assume that the currently detected / received SSB is SSB2.

[0399] Example 3-5

[0400] Whether the SSB is SSB1 or SSB2 can be indicated through the value of a specific field within the PBCH / MIB included in the SSB. For example, if the value of the field is 0, it can indicate SSB1, and if the value is 1, it can indicate SSB2.

[0401] Example 3-6

[0402] The PBCH / MIB region can also be divided into multiple parts and arranged within the SSB structure. For example, if the PBCH is divided into two parts, one SSB may include some or all of the PSS, SSS, PBCH1, and PBCH2.

[0403] For example, during the initial access process, the terminal may decode only PBCH1 (detect / receive PSS and SSS), and may not decode PBCH2 (even if transmitted).

[0404] For example, for measurements on neighboring cells, only PBCH2 may be decoded (by detecting / receiving PSS and SSS), or both PBCH1 and PBCH2 may be decoded.

[0405] For example, PBCH2 may be included only in SSB1 and not in SSB2. Alternatively, SSB1 may include PBCH1 and SSB2 may include PBCH2.

[0406] For example, key information related to initial access may be included in PBCH1, and key information related to neighboring cell measurements may be included in PBCH2.

[0407] The period of the corresponding PBCH in the SSB including PBCH1 may be different from the period of the corresponding PBCH in the SSB including PBCH2. For example, the elements may be transmitted separately, as in the example of FIG. 20(b).

[0408] The content of PBCH2 may correspond to a portion of the content of PBCH1. Alternatively, the content of PBCH1 may correspond to a portion of the content of PBCH2.

[0409] The PBCH may be split into multiple parts, transmitted at different resource sizes / locations within the SSB, and transmitted at different periods, and these characteristics may be predefined and applied without separate signaling, or may be pre-configured.

[0410] According to the examples described above, the terminal can clearly determine whether the detected SSB is SSB1 or SSB2 based on the information included in the PBCH / MIB included in the SSB during the initial access process. For example, if the detected SSB corresponds to SSB1, the terminal can assume that SSB1 will also be transmitted in the next (for SSB1) cycle. Alternatively, if the detected SSB corresponds to SSB2, the terminal can know that the SSB transmission in the next cycle is uncertain (for example, the base station may turn off the transmission of SSB2). Furthermore, the terminal can clearly determine the cycle of the detected SSB based on the information included in the PBCH / MIB included in the SSB. For example, if the cycle of the detected SSB is confirmed to be P, the terminal can expect that the corresponding SSB will be transmitted after a time P.

[0411] Example 4

[0412] Additional examples of how the terminal distinguishes SSBn during the initial access process of the terminal are described below.

[0413] Example 4-1

[0414] In the existing SSB, there are PSS, SSS, and PBCH DMRS, which are defined as sequences. In addition, a new terminal sequence for SSBn (e.g., a sequence that distinguishes between SSB1 and SSB2) can be defined and included within the SSB structure.

[0415] FIG. 24 is a drawing showing an example of the structure of an SSB to which the present disclosure can be applied.

[0416] In the example of Fig. 24, a new terminal sequence may be placed in an unused PRB of a PSS transmission OFDM symbol. In this case, the maximum power boosting value of the PSS may be limited depending on the number of PRBs in which the new terminal sequence is placed. For example, in the existing SSB structure, an additional power boosting of 0 to 3 dB may be applied to the PSS compared to the SSS or PBCH, but the maximum power boosting range may be reduced in proportion to the number of PRBs in which the new terminal sequence is placed. For example, if the new terminal sequence is placed in two PRBs, a power boosting of 0 to 2 dB may be applied to the PSS. For example, if the new terminal sequence is placed in four PRBs, a power boosting of 0 to 1 dB may be applied to the PSS. For example, if the number of PRBs in which the new terminal sequence is placed is five or more, the same power as that of the SSS or PBCH may be applied to the PSS. In this way, a scaling value for power boosting according to the number of PRBs in which a new terminal sequence is placed may be introduced, or a power boosting value corresponding to the number of PRBs may be defined in advance in the form of a table.

[0417] Example 4-2

[0418] The terminal can detect and decode SSB based on the predefined cycles of SSB1 and SSB2. For example, the terminal may be able to detect and decode SSB based on the predefined cycle only for SSB1. In cases where the base station can turn transmission on and off, such as SSB2, even if SSB is detected based on the predefined cycle, a cycle longer than the predefined cycle of SSB1 may not be applied.

[0419] Example 4-3

[0420] SSB1 includes three elements: PSS, SSS, and PBCH. SSB2 also includes three elements: PSS, SSS, and PBCH. Different structures may be applied to SSB1 and SSB2. For example, the size / location / order of time-frequency resources in which each element is allocated within a specific bandwidth may differ between SSB1 and SSB2. For example, the locations / orders of REs, PRBs, OFDM symbols, and the locations / orders of signals (PSS / SSS / DMRS) may differ between SSB1 and SSB2.

[0421] For example, as in the example of Fig. 24, in SSB1, the location of SSS is the 3rd OFDM symbol, but in SSB2, SSS may be located in the 2nd OFDM symbol.

[0422] Example 4-4

[0423] It can be defined that PBCH / MIB is not transmitted in SSB2, and PBCH / MIB is transmitted only in SSB1. It can be assumed that the terminal estimates cell identification information through decoding during the initial access process for SSB2.

[0424] For SSB2, it can be defined that only PSS is transmitted for NES, one synchronization signal / channel is transmitted, or PBCH / MIB transmission is turned on / off.

[0425] Example 4-5

[0426] It can be defined that SSB2 is transmitted at least x (x=1, 2, 3, ...) times between the transmission of SSB1 and SSB2. In this case, it can be assumed that the terminal can receive SSB2 at least x times after detecting / receiving SSB1 before receiving the next SSB1.

[0427] For example, the value of x may be predefined or may be set for the terminal by a higher layer.

[0428] Example 4-6

[0429] The period corresponding to the least common multiple of the transmission periods of SSB1 and SSB2 can be defined as the default period. During the initial access process, the terminal can perform SSB detection / decoding based on the default period.

[0430] If both SSB1 and SSB2 can be transmitted, the period of SSB1 and the period of SSB2 can be defined to satisfy the default period. The relationship between these periods can also be defined by a table or formula.

[0431] For example, the period of SSB2 may be predefined to be 1 / N times the period of SSB1. The value of N may be predefined so that the terminal can derive it based on the difference in the synchronization raster or sequence.

[0432] Example 4-7

[0433] The transmission of SSB2 is defined as being transmitted once between transmission wnrls of SSB1, and the transmission period of SSB2 is kept the same as that of SSB1, but the transmission time of SSB2 can be changed by a time offset value referenced to the transmission time of SSB1.

[0434] FIG. 25 is a diagram showing examples of transmission of various SSBs according to the present disclosure.

[0435] SSB1 may contain information indicating whether SSB2 is transmitted.

[0436] SSB2 may contain time offset information for the subsequent SSB.

[0437] If the time offset applied to SSB2 is 0, it can be predefined to indicate that there will be no transmission of SSB2 between SSB1 transmission cycles.

[0438] Example 4-8

[0439] During the initial access process, when searching / detecting an SSB, a UE may detect a non-cell-defining (NCD)-SSB. The PBCH / MIB of the CD-SSB may include configuration information for a CORESET / search space for monitoring a DCI including information for scheduling a PDSCH including SIB1, whereas the PBCH / MIB of the NCD-SSB may not include such configuration information. Based on specific information in the PBCH / MIB of the NCD-SSB, the UE may obtain information on frequency resources where only SSB1 is transmitted (e.g., the location of the second synchronization raster) and / or information on frequency resources where both SSB1 and SSB2 can be transmitted (e.g., the location of the second synchronization raster).

[0440] It can be assumed that the synchronization raster position where the NCD-SSB is transmitted is S1, the synchronization raster position where only SSB1 is transmitted is S2, and the synchronization raster position where SSB1 and SSB2 can be transmitted is S3. In this case, information about S2 and / or information about S3 can be signaled through the NCD-SSB. Alternatively, information about the value of S2-S1 and / or information about the value of S3-S1 can be signaled through the NCD-SSB.

[0441] Alternatively, it may be indicated via NCD-SSB that there is no frequency resource that transmits only SSB1 within a specific area, and / or that there is no frequency resource that can transmit both SSB1 and SSB2.

[0442] When a terminal detects an SSB, it can determine at what frequency position the detected SSB is within the carrier bandwidth based on a parameter (e.g., k_SSB) indicating a subcarrier offset of the SSB from point A. This parameter may be included in a PBCH / MIB within the SSB. Similarly, a PBCH / MIB included in an NCD-SSB may indicate, instead of the k_SSB parameter for the SSB in question, a k_SSB parameter for a frequency resource of another SSB (e.g., a first frequency resource on which SSB1 and SSB2 can be transmitted, and / or a second frequency resource on which SSB1 is transmitted).

[0443] According to the various examples of the present disclosure described above, a base station can implicitly instruct a terminal to switch between various services / modes supported by the base station by transmitting SSBs distinguished by SSBn. In addition, energy saving efficiency can be increased by operating separately the case where SSBs are always transmitted periodically in a specific mode (e.g., NES) and the SSBs whose transmission can be turned on / off. Even when SSBs are transmitted by distinguishing them as SSB1 and SSB2, etc., by defining how the terminal determines when the transmission of SSB2 is uncertain and what assumptions are applied for this, according to the examples described above, the transmission of SSBs for energy saving can be considered not only in the RRC connected / idle / deactivated states of the terminal, but also in the initial access state, thereby significantly improving cell energy saving. Furthermore, when the network continuously transmits the default signal, not only the problem of network energy consumption but also the problem of causing interference in the cell overlapping area can occur. As the demand for high-frequency bands grows, the installation of narrower and more numerous cells / base stations is required, resulting in higher cell density and greater need for inter-cell interference reduction. Therefore, for the purpose of inter-cell interference reduction as well as NES, various examples of the present disclosure related to SSB transmission can be applied to minimize the transmission of AO SSB and transmit additional OD SSB (or SSB with some elements missing) as needed, thereby enabling terminals to accurately perform measurements based on various SSBs, thereby enabling more efficient network operation.

[0444] 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.

[0445] 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 essential characteristics thereof. 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.

[0446] The scope of the present disclosure includes software or machine-executable instructions (e.g., an operating system, an application, firmware, a program, etc.) that cause operations according to the methods of various embodiments to be executed on a device or a computer, and a non-transitory computer-readable medium having such software or instructions stored thereon and executable on the device or computer. Instructions that can be used to program a processing system to perform the features described in the present disclosure can be stored on / in a storage medium or a computer-readable storage medium, and a computer program product including such a storage medium can be used to implement the features described in the present disclosure. The storage medium can include, but is not limited to, high-speed random access memory, such as DRAM, SRAM, DDR RAM, or other random access solid state memory devices, and can include non-volatile memory, such as one or more magnetic disk storage devices, optical disk storage devices, flash memory devices, or other non-volatile solid state storage devices. The memory optionally includes one or more storage devices remotely located from the processor(s). The memory or, alternatively, the non-volatile memory device(s) within the memory comprise a non-transitory computer-readable storage medium. The features described in this disclosure may be incorporated into software and / or firmware stored on any of the machine-readable media, which may control the hardware of the processing system and allow the processing system to interact with other mechanisms that utilize results according to embodiments of the present disclosure. Such software or firmware may include, but is not limited to, application code, device drivers, operating systems, and execution environments / containers.

[0447] Here, the wireless communication technology implemented in the device of the present disclosure may include not only LTE, NR, and 6G, but also Narrowband Internet of Things for low-power communication. For example, NB-IoT technology may be an example of LPWAN (Low Power Wide Area Network) technology and may be implemented with standards such as LTE Cat NB1 and / or LTE Cat NB2, and is not limited to the above-described names. Additionally or alternatively, the wireless communication technology implemented in the device of the present disclosure may perform communication based on LTE-M technology. For example, LTE-M technology may be an example of LPWAN technology and may be called by various names such as eMTC (enhanced Machine Type Communication). For example, LTE-M technology can be implemented by at least one of various standards such as 1) LTE CAT 0, 2) LTE Cat M1, 3) LTE Cat M2, 4) LTE non-BL (non-Bandwidth Limited), 5) LTE-MTC, 6) LTE Machine Type Communication, and / or 7) LTE M, and is not limited to the above-described names. Additionally or alternatively, the wireless communication technology implemented in the device (100, 200) of the present disclosure can include at least one of ZigBee, Bluetooth, and Low Power Wide Area Network (LPWAN) considering low-power communication, and is not limited to the above-described names. For example, ZigBee technology can create personal area networks (PAN) related to small / low-power digital communication based on various standards such as IEEE 802.15.4, and can be called by various names.

[0448] The method proposed in this disclosure is explained with a focus on examples applied to 3GPP LTE / LTE-A, 5G, and 6G systems, but can be applied to various wireless communication systems in addition to 3GPP LTE / LTE-A, 5G, and 6G systems.

Claims

1. A step of receiving a first synchronization signal group and a second synchronization signal group from a first frequency resource; and A step of performing a measurement based on the first synchronization signal group and the second synchronization signal group based on the second synchronization signal group being received in the first frequency resource, A method wherein the first synchronization signal group and the second synchronization signal group are distinguished based on a sequence group or at least one of information included in each of the first synchronization signal group and the second synchronization signal group.

2. In paragraph 1, A method wherein the first frequency resource is distinguished from a second frequency resource where the second synchronization signal group is not transmitted and where the first synchronization signal group is transmitted.

3. In paragraph 2, A method wherein at least one candidate of the first frequency resource and at least one candidate of the second frequency resource are predefined as a synchronization raster.

4. In paragraph 2, The location of one or more candidates of the first frequency resource is spaced apart from the location of one or more candidates of the second frequency resource by a specific offset, or A method wherein one or more candidates of the second frequency resource and one or more candidates of the first frequency resource are alternately positioned in the frequency domain.

5. In paragraph 1, The first sequence group includes one or more sequence candidates mapped to the first synchronization signal group, and the second sequence group includes one or more sequence candidates mapped to the second synchronization signal group. A method wherein the sequence candidate is associated with a sequence of one or more signals among a first synchronization signal, a second synchronization signal, or a demodulation reference signal.

6. In paragraph 1, The first synchronization signal group is transmitted based on the first synchronization signal group period, and the second synchronization signal group is transmitted based on the second synchronization signal group period, A method in which different sequence groups correspond to different synchronization signal group periods.

7. In paragraph 1, The first sequence group corresponds to one or more elements of the first group included in the second synchronization signal group, The second sequence group corresponds to one or more elements of the second group included in the second synchronization signal group, A method wherein said one or more elements include at least one of a first synchronization signal, a second synchronization signal, or system information.

8. In paragraph 1, The information included in the first synchronization signal group is included in the system information within the first synchronization signal group, A method in which information included in the second synchronization signal group is included in system information within the second synchronization signal group.

9. In paragraph 1, The information included in the first synchronization signal group is a first system frame number (SFN), and the information included in the second synchronization signal group is a second SFN. A method in which the first synchronization signal group and the second synchronization signal group are distinguished based on the results of the modulo operation for each of the first SFN and the second SFN.

10. In paragraph 1, The information included in the first synchronization signal group includes information about the period or transmission of the second synchronization signal group, A method wherein the information included in the second synchronization signal group includes information about the period or transmission time of the next synchronization signal group.

11. In paragraph 1, One or more of the number or locations of physical resources to which information included in the first synchronization signal group is mapped is distinct from one or more of the number or locations of physical resources to which information included in the first synchronization signal group is mapped, A method wherein the above physical resource includes at least one of a time resource or a frequency resource.

12. In paragraph 1, A method in which information included in the second synchronization signal group is set to a value indicating the second synchronization signal group.

13. In paragraph 1, The information included in the first synchronization signal group is set to a value indicating the first synchronization signal group, A method in which information included in the second synchronization signal group is set to a value indicating the second synchronization signal group.

14. In paragraph 1, A method wherein the first system information included in the first synchronization signal group and the second system information included in the second synchronization signal group are distinguished based on at least one of content, mapping location, inclusion of some content, or period.

15. In paragraph 1, A method, wherein each of the first synchronization signal group and the second synchronization signal group includes an additional sequence that distinguishes the first synchronization signal group and the second synchronization signal group.

16. In paragraph 1, A method wherein different periods are predefined for the first synchronization signal group and the second synchronization signal group.

17. In paragraph 1, The first synchronization signal group corresponds to one or more elements of the first position, and the second synchronization signal group corresponds to one or more elements of the second position, A method wherein said one or more elements include at least one of a first synchronization signal, a second synchronization signal, or system information.

18. In paragraph 1, A method wherein the first synchronization signal group includes system information, and the second synchronization signal group does not include system information.

19. In paragraph 1, A third synchronization signal group includes information about the first frequency domain and a second frequency domain in which the second synchronization signal group is not transmitted and in which the first synchronization signal group is transmitted, The method wherein the third synchronization signal group corresponds to a non-cell defining synchronization signal group.

20. In paragraph 1, A method wherein the second synchronization signal group is transmitted based on an on-demand SSB setting.

21. One or more transceivers; and comprising one or more processors connected to said one or more transceivers, One or more of the above processors: Receiving at least one of a first synchronization signal group and a second synchronization signal group from a first frequency resource through a transceiver; and Based on the second synchronization signal group being received in the first frequency resource, measurement is set to be performed based on the first synchronization signal group and the second synchronization signal group, A terminal wherein the first synchronization signal group and the second synchronization signal group are distinguished based on a sequence group or at least one of the information included in each of the first synchronization signal group and the second synchronization signal group.

22. A step of transmitting a first synchronization signal group and a second synchronization signal group to one or more terminals in a first frequency resource; and A step of receiving an initial access signal from a first terminal based on a measurement based on the first synchronization signal group and the second synchronization signal group of the first terminal among the one or more terminals, A method wherein the first synchronization signal group and the second synchronization signal group are distinguished based on a sequence group or at least one of information included in each of the first synchronization signal group and the second synchronization signal group.

23. One or more transmitters and receivers; and comprising one or more processors connected to said one or more transceivers, One or more of the above processors: Transmitting a first synchronization signal group and a second synchronization signal group to one or more terminals through the one or more transceivers in the first frequency resource; and Based on measurements based on the first synchronization signal group and the second synchronization signal group of the first terminal among the one or more terminals, an initial access signal from the first terminal is set to be received through the one or more transceivers, A base station, wherein the first synchronization signal group and the second synchronization signal group are distinguished based on a sequence group or at least one of the information included in each of the first synchronization signal group and the second synchronization signal group.

24. One or more processors; and A processing device comprising one or more computer memories operatively connected to said one or more processors and storing instructions for performing a method according to any one of claims 1 to 20 based on execution by said one or more processors.

25. One or more non-transitory computer-readable media storing one or more instructions that are executed by one or more processors to control the performance of a method according to any one of claims 1 to 20.

Images