Method for receiving downlink signal, user equipment, processing device and storage medium, and method for transmitting downlink signal, base station, processing device and storage medium

Abstract

The UE receives downlink control information (DCI) based on a default mode set as a default from among a TN mode in which TN cell-based transmission and reception of a signal are performed and an NTN mode in which NTN cell-based transmission and reception of a signal are performed on a first frequency band supporting TN and NTN, and can switch to a non-default mode, which is not set to be default, from among the NTN mode and the TN mode, based on indication information indicating switching of the mode in the DCI.

Description

TECHNICAL FIELD

[0001] The disclosure relates to a wireless communication system. BACKGROUND

[0002] Various technologies such as machine-to-machine (M2M) communication, machine type communication (MTC), and various devices requiring high data throughput such as smart phones and tablet personal computers (PCs) have emerged and are popularized. Accordingly, the amount of data throughput that needs to be processed in a cellular network rapidly increases. In order to meet such rapidly increasing data throughput, a carrier aggregation technology or a cognitive radio technology for efficiently employing more frequency bands and a multiple input multiple output (MIMO) technology or a multi-base station (BS) cooperation technology for increasing data capacity transmitted on limited frequency resources have been developed.

[0003] Recently, it is considered to support a wireless communication service through a non-terrestrial network (NTN) in order to provide a wireless communication service in a place where a ground connection is technically very difficult or it is very expensive to provide a wireless communication service through a ground network. SUMMARY

[0004] TECHNICAL PROBLEM

[0005] There is a need for a method of accurately and efficiently providing a wireless communication signal to a user equipment (UE) via an airborne platform or space.

[0006] There is a need for a method of efficient coexistence for a ground network and a non-terrestrial network (NTN).

[0007] Objects to be achieved by the disclosure are not limited to the above already specifically described, and other objects not described herein will be more clearly understood by a person skilled in the art from the following detailed description.

[0008] TECHNICAL SOLUTION

[0009] According to an aspect, a method of receiving a downlink signal by a user equipment (UE) in a wireless communication system includes the steps of connecting with a terrestrial network (TN) cell and a non-terrestrial network (NTN) cell on a first frequency band; receiving downlink control information (DCI) based on a default mode configured as default among a TN mode in which TN cell-based transmission and reception of a signal are performed and an NTN mode in which NTN cell-based transmission and reception of a signal are performed; and switching to a non-default mode which is not configured as default among the NTN mode and the TN mode based on indication information of switching of an indicated mode in the DCI, and receiving a signal based on the non-default mode.

[0010] The default mode can be configured as the TN mode, and the non-default mode is configured as the NTN mode.

[0011] The reception of signals based on the non-default mode can be performed after a specific time interval from the first time slot for sending a message including an acknowledgment (ACK) for DCI or the second time slot for receiving DCI.

[0012] Since DCI does not include data scheduling information, signal reception based on a non-default mode can be performed after a specific time interval from the first time slot.

[0013] Based on DCI, which includes data scheduling information, signal reception in a non-default mode can be performed after a specific time interval from the second time slot.

[0014] The specific interval may include a first time interval applied when switching from TN mode to NTN mode and a second time interval applied when switching from NTN mode to TN mode.

[0015] Non-default mode can be activated until the preset timer expires, and the UE can revert to default mode based on the expiration of the preset timer.

[0016] The preset timer can be reset or initialized based on the reception of DCI, which includes data scheduling information, in non-default mode.

[0017] Non-default modes can be activated during the mode activation period included in the DCI, and the UE can revert to the default mode when the mode activation period has passed.

[0018] The UE can fall back to the default mode based on the reception of DCI in non-default mode, including inactivity indicators or mode termination indicators.

[0019] According to another aspect, a user equipment (UE) for receiving downlink signals in a wireless communication system includes: at least one transceiver; at least one processor; and at least one computer memory operatively connectable to the at least one processor and storing instructions that, when executed, cause the at least one processor to perform operations, wherein the operations include: connecting to a terrestrial network (TN) cell and a non-terrestrial network (NTN) cell in a first frequency band; receiving downlink control information (DCI) based on a default mode configured as the default among TN and NTN modes, performing signal transmission and reception based on TN cells in the TN mode and NTN cells in the NTN mode; and switching to a non-default mode not configured as the default among NTN and TN modes based on indication information indicating mode switching in the DCI, and receiving signals based on the non-default mode.

[0020] According to another aspect, a method for transmitting downlink signals from a base station (BS) to a user equipment (UE) connected to a terrestrial network (TN) cell and a non-terrestrial network (NTN) cell in a wireless communication system includes the following steps: instructing the UE to select a mode as a default mode between a TN mode and an NTN mode, wherein in the TN mode, signal transmission and reception based on the TN cell are performed, and in the NTN mode, signal transmission and reception based on the NTN cell are performed; and transmitting downlink control information (DCI), the DCI including indication information indicating a switch from the default mode to a non-default mode among the NTN mode and the TN mode that is not configured as the default.

[0021] The above-described solutions are merely a part of the examples of this disclosure, and those skilled in the art can deduce and understand the various examples incorporated into the technical features of this disclosure based on the following detailed description.

[0022] Beneficial effects

[0023] According to various implementation methods, wireless communication signals can be transmitted / received efficiently via airborne platforms or space. Therefore, the overall throughput of the wireless communication system can be increased.

[0024] According to various implementation methods, the continuity of wireless communication services can be ensured, the reliability of wireless communication services can be enhanced through the connectivity between various access technologies, and the network resilience and reliability in the face of disasters can be improved.

[0025] Depending on the implementation of various methods, the coexistence of non-terrestrial networks (NTN) and terrestrial networks (NT) can be supported.

[0026] According to some implementations of various methods, even when NTN and TN bands coexist, the user equipment (UE) can effectively detect the synchronization signal block (SSB).

[0027] The effects of various embodiments are not limited to those specifically described above, and those skilled in the art related to this disclosure will understand more clearly from the following detailed description other effects not described herein. Attached Figure Description

[0028] The accompanying drawings are intended to provide an understanding of the disclosure, illustrate various embodiments of the disclosure, and, together with the description in the specification, serve to explain the principles of the disclosure.

[0029] FIG. 1 An example of a communication system 1 that applies the implementation of the present disclosure is shown.

[0030] FIG. 2This is a block diagram illustrating an example of a communication device capable of performing the methods according to this disclosure.

[0031] FIG. 3 An example of a frame structure used in a 3GPP-based wireless communication system is shown.

[0032] FIG. 4 An example of a time-slot resource grid is shown.

[0033] FIG. 5 Multi-beam operation in a 3GPP-based system is illustrated.

[0034] FIG. 6 An example of sending an SS / PBCH block (SSB) on a cell is shown.

[0035] FIG. 7 An example of a non-terrestrial network (NTN) structure is shown.

[0036] FIG. 8 Examples of synchronization grids and channel grids used in some implementations are shown.

[0037] FIG. 9 An example of an SSB structure is shown.

[0038] FIG. 10 This is a diagram showing the signal flow for the PDCCH transmission and reception process.

[0039] FIG. 11 The example illustrates the coexistence of terrestrial networks (TN) and non-terrestrial networks (NTN).

[0040] FIG. 12 This is a diagram illustrating a method by which a UE receives data or signals from a TN or NTN cell.

[0041] FIG. 13 and FIG. 14 This diagram is used to explain the method by which a UE switches modes based on received downlink control information.

[0042] FIG. 15 and FIG. 16 An example is given of a method for switching execution modes based on the NTI included in the DCI.

[0043] FIG. 17 to FIG. 19 This diagram illustrates the method by which a UE performs a fallback operation between TN and NTN modes.

[0044] FIG. 20 This is a diagram used to explain the method by which a UE receives downlink signals. Detailed Implementation

[0045] In the following, embodiments according to the present disclosure will be described in detail with reference to the accompanying drawings. The detailed description given below with reference to the drawings is intended to explain exemplary implementations of the present disclosure, and not to show the only implementations that can be implemented according to the present disclosure. The following detailed description includes specific details to provide a thorough understanding of the present disclosure. However, it will be apparent to those skilled in the art that the present disclosure can be practiced without such specific details.

[0046] In some cases, known structures and devices may be omitted or shown in block diagram form, focusing on the essential features of the structures and devices without obscuring the concept of this disclosure. Throughout this disclosure, the same reference numerals will be used to refer to the same or similar parts.

[0047] The technologies, devices, and systems described below can be applied to a variety of wireless multiple access systems.

[0048] For ease of description, the description will be based on communication systems according to the 3rd Generation Partnership Project (3GPP). However, the technical features of this disclosure are not limited thereto. For example, although the following detailed description is based on 3GPP LTE or 5G technology, some implementations of this disclosure are applicable to any other mobile communication system and systems to be introduced in the future (e.g., 6G), unless they are specific to 3GPP LTE / 5G.

[0049] For any terms and techniques not described in detail in this disclosure, reference may be made to 3GPP-based standard specifications, such as 3GPP TS 23.304, 3GPP TS 23.285, 3GPP TS 23.287, 3GPP TS 24.587, 3GPP TS 36.211, 3GPP TS 36.212, 3GPP TS 36.213, 3GPP TS 36.300, 3GPP TS 36.321, 3GPP 36.322, 3GPP TS 36.323, 3GPP TS and 3GPP TS 36.331, 3GPP TS 37.213, 3GPP TS 38.211, 3GPP TS 38.212, 3GPP TS 38.213, and 3GPP TS 38.213. 38.214, 3GPP TS 38.300, 3GPP TS38.321, 3GPP TS 38.322, 3GPP TS 38.323, 3GPP TS 38.331, etc.

[0050] In the examples of this disclosure described later, if the apparatus “assumes” something, this could mean that the channel transmitting entity transmits the channel according to the corresponding “assumption.” It could also mean that the channel receiving entity receives or decodes the channel in a manner consistent with the “assumption,” provided that the channel has already been transmitted according to the “assumption.”

[0051] In this disclosure, a user equipment (UE) can be fixed or mobile. Each of various devices that transmits and / or receives user data and / or control information by communicating with a base station (BS) can be a UE. The term UE can be referred to as a terminal device, mobile station (MS), mobile terminal (MT), user terminal (UT), subscriber station (SS), radio device, personal digital assistant (PDA), wireless modem, handheld device, etc. In this disclosure, a BS refers to a fixed station that communicates with a UE and / or another BS and exchanges data and control information with the UE and another BS. The term BS can be referred to as an advanced base station (ABS), Node-B (NB), evolved Node-B (eNB), gNB, base transceiver system (BTS), access point (AP), processing server (PS), etc. Specifically, a BS for Universal Terrestrial Radio Access (UTRAN) is called an NB, a BS for Evolved-UTRAN (E-UTRAN) is called an eNB, and a BS for New Radio Access Technology networks is called a gNB. In the following, for ease of description, NB, eNB, or gNB will be referred to as BS, regardless of the type or version of the communication technology.

[0052] In this disclosure, a node refers to a fixed point capable of sending / receiving radio signals to / from a UE via communication with the UE. Various types of BSs can be used as nodes, regardless of their name. Each node is equipped with at least one antenna. An antenna can refer to a physical antenna port or a virtual antenna or antenna array. A node can also be referred to as a point.

[0053] 3GPP-based communication systems use the concept of cells to manage radio resources, and the cells associated with radio resources are different from cells in a geographical area. A "cell" in a geographical area can be understood as the coverage area where a node can provide services using a carrier, and a "cell" in radio resources is related to bandwidth (BW), which is the frequency range configured by the carrier. Since the DL coverage area, which is the range where a node can transmit valid signals, and the UL coverage area, which is the range where a node can receive valid signals from a UE, depend on the carrier carrying the signal, a node's coverage area can also be related to the coverage area of ​​the "cell" of radio resources used by the node. Therefore, the term "cell" can be used to indicate the service coverage area of ​​a node at some point, the radio resources at other times, or the range where a signal using radio resources can reach with effective strength at other times.

[0054] A “cell” associated with radio resources is defined by a combination of DL resources and UL resources (that is, a combination of DL component carriers (CCs) and UL CCs). A cell can be configured with only DL resources or a combination of DL and UL resources. If carrier aggregation is supported, the relationship between the carrier frequencies of the DL resources (or DL ​​CCs) and the carrier frequencies of the UL resources (or UL CCs) can be indicated by system information. In this case, the carrier frequencies can be equal to or different from the center frequency of each cell or CC.

[0055] In a wireless communication system, the UE receives information from the BS on the DL and transmits information to the BS on the UL. The information transmitted and / or received by the BS and UE includes data and various control information, and various physical channels exist depending on the type / purpose of the information transmitted and / or received by the UE and BS.

[0056] 3GPP-based communication standards define DL physical channels corresponding to resource elements that carry information originating from higher layers and DL physical signals corresponding to resource elements used by the physical layer but not carrying information originating from higher layers. For example, the Physical Downlink Shared Channel (PDSCH), Physical Broadcast Channel (PBCH), and Physical Downlink Control Channel (PDCCH) are defined as DL physical channels, and reference signals (RS) and synchronization signals (SS) are defined as DL physical signals. RS, also known as pilot signals, represents signals with predefined special waveforms known to both the BS and UE. For example, demodulation reference signals (DMRS) and channel state information RS (CSI-RS) are defined as DL RS. 3GPP-based communication standards also define UL physical channels corresponding to resource elements that carry information originating from higher layers and UL physical signals corresponding to resource elements used by the physical layer but not carrying information originating from higher layers. For example, the Physical Uplink Shared Channel (PUSCH), Physical Uplink Control Channel (PUCCH), and Physical Random Access Channel (PRACH) are defined as UL physical channels, and the DMRS for UL control / data signals and the SRS for UL channel measurements are defined.

[0057] In this disclosure, PDCCH refers to a set of time-frequency resources (e.g., resource elements (REs)) that serve as a set of REs carrying downlink control information (DCI), and PDSCH refers to a set of time-frequency resources that serve as a set of REs carrying DL data. PUCCH, PUSCH, and PRACH refer to a set of time-frequency resources that are sets of time-frequency REs carrying uplink control information (UCI), UL data, and random access preambles, respectively. In the following description, "UE / BS transmits / receives PUCCH / PUSCH / PRACH" means that the UE / BS transmits / receives UCI / UL data / random access preambles on or through PUCCH / PUSCH / PRACH. Additionally, "BS / UE transmits / receives PBCH / PDCCH / PDSCH" means that the BS / UE transmits / receives broadcast information / DCI / DL data on or through PBCH / PDCCH / PDSCH.

[0058] In this disclosure, radio resources (e.g., time-frequency resources) scheduled or configured by the BS to the UE for the transmission or reception of PUCCH / PUSCH / PDSCH can be referred to as PUCCH / PUSCH / PDSCH resources.

[0059] Since the communication device receives physical channels and / or physical signals in the form of radio signals over a cell, it can select and receive radio signals that only include specific physical channels or specific physical signals without using a radio frequency (RF) receiver, or select and receive radio signals that do not have specific physical channels or specific physical signals using an RF receiver. In practice, the communication device receives radio signals over a cell via an RF receiver, converts the radio signals, which are RF band signals, into baseband signals, and then uses one or more processors to decode the physical signals and / or physical channels in the baseband signals. Therefore, in some implementations of this disclosure, not receiving physical signals and / or physical channels may mean that the communication device does not attempt to recover physical signals and / or physical channels from radio signals, for example, does not attempt to decode physical signals and / or physical channels, rather than that the communication device actually does not receive radio signals that include the corresponding physical signals and / or physical channels.

[0060] FIG. 1 An example of a communication system 1 that applies the implementation of the present disclosure is shown.

[0061] Reference FIG. 1The communication system 1 applied in this disclosure includes a wireless device, a BS, and a network. Here, a wireless device refers to a device that performs communication using wireless access technologies (e.g., 5G NR (New RAT), LTE (e.g., E-UTRA), WiFi, or 6G to be introduced in the future).

[0062] Wireless devices may include, but are not limited to, robots 100a, vehicles 100b-1, 100b-2, 100b-3 and 100b-4, extended reality (XR) devices 100c, handheld devices 100d, home appliances 100e, Internet of Things (IoT) devices 100f, and artificial intelligence (AI) devices / servers 400. For example, vehicles may include ground vehicles with wireless communication capabilities, autonomous vehicles, and vehicles capable of performing vehicle-to-vehicle communication. Here, vehicles may include unmanned aerial vehicles (UAVs) (e.g., drones) and urban air traffic (UAM) (e.g., unmanned aerial vehicles). XR devices may include augmented reality (AR) / virtual reality (VR) / mixed reality (MR) devices. Handheld devices may include smartphones, smart tablets, wearable devices (e.g., smartwatches or smart glasses), and computers (e.g., laptops). Home appliances may include TVs, refrigerators, and washing machines. IoT devices may include sensors and smart meters. For example, a BS and network may also be implemented as wireless devices, and a particular wireless device may operate as a BS / network node relative to another wireless device.

[0063] Wireless devices 100a to 100f can connect to the network via BS 200. Artificial intelligence (AI) technology can be applied to wireless devices 100a to 100f, and wireless devices 100a to 100f can connect to AI server 400 via the network. While wireless devices 100a to 100f can communicate with each other via BS 200 / network, they can also perform direct communication with each other without going through the BS / network (e.g., sidelink communication). For example, vehicles 100b-1, 100b-2, 100b-3, and 100b-4 can perform direct communication (e.g., vehicle-to-vehicle (V2V) / vehicle-to-everything (V2X) communication). IoT devices (e.g., sensors) can perform direct communication with other IoT devices (e.g., sensors) or other wireless devices 100a to 100f.

[0064] Wireless communication / connections can be established between wireless devices 100a to 100f and BS 200, as well as between wireless devices 100a to 100f. Here, wireless communication / connections such as UL / DL communication and side-link (SL) communication (or device-to-device (D2D) communication) can be established using various wireless access technologies (e.g., 5G NR). The wireless devices and the BS / wireless devices can transmit / receive radio signals to / from each other via wireless communication / connections (UL / DL, SL). For this purpose, at least a portion of various configuration information configuration processes, various signal processing processes (e.g., channel coding / decoding, modulation / demodulation, and resource mapping / demapping), and resource allocation processes for transmitting / receiving radio signals can be performed based on various proposals of this disclosure.

[0065] FIG. 2 This is a block diagram illustrating an example of a communication device capable of performing the methods according to this disclosure. (See also...) FIG. 2 The first wireless device 100 and the second wireless device 200 can transmit and / or receive radio signals using various wireless access technologies. Here, {first wireless device 100 and second wireless device 200} can correspond to... FIG. 1 {Wireless Device 100x and BS200} and / or {Wireless Device 100x and Wireless Device 100x}.

[0066] The first wireless device 100 and the second wireless device 200 may include one or more processors 102 and 202 and one or more memories 104 and 204, and additionally include one or more transceivers 106 and 206 and / or one or more antennas 108 and 208, respectively. Processors 102 and 202 may control memories 104 and 204 and / or transceivers 106 and 206, and may be configured to implement the functions, processes, and / or methods described / presented below. For example, processors 102 and 202 may process information in memories 104 and 204 to generate first information / signals, and then transmit radio signals including the first information / signals via transceivers 106 and 206. Processors 102 and 202 may receive radio signals including second information / signals via transceivers 106 and 206, and then store the information obtained by processing the second information / signals in memories 104 and 204. Memory 104 and 204 may be connected to processor 102 and 202 and may store various information related to the operation of processor 102 and 202. For example, memory 104 and 204 may execute part or all of a process controlled by processor 102 and 202, or store software code including instructions for performing the processes and / or methods described / presented later. Here, processor 102 and 202 and memory 104 and 204 may be part of a communication modem / circuit / chip designed to implement a wireless access technology. Transceiver 106 and 206 may be connected to processor 102 and 202 and transmit and / or receive radio signals via one or more antennas 108. Each of transceiver 106 and 206 may include a transmitter and / or a receiver.

[0067] One or more protocol layers may be implemented by, but not limited to, one or more processors 102 and 202. For example, one or more processors 102 and 202 may implement one or more layers (e.g., functional layers, such as the Physical (PHY) layer, Media Access Control (MAC) layer, Radio Link Control (RLC) layer, Packet Data Convergence Protocol (PDCP) layer, Radio Resource Control (RRC) layer, and Service Data Adaptation Protocol (SDAP) layer). One or more processors 102 and 202 may generate one or more Protocol Data Units (PDUs) and / or one or more Service Data Units (SDUs) according to the functions, processes, proposals, and / or methods disclosed in this disclosure. One or more processors 102 and 202 may generate messages, control information, data, or information according to the functions, processes, proposals, and / or methods disclosed in this disclosure. One or more processors 102 and 202 may generate signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data, or information, according to the functions, processes, suggestions, and / or methods disclosed in this disclosure, and provide the generated signals to one or more transceivers 106 and 206. One or more processors 102 and 202 may receive signals (e.g., baseband signals) from one or more transceivers 106 and 206, and acquire PDUs, SDUs, messages, control information, data, or information according to the functions, processes, suggestions, and / or methods disclosed in this disclosure.

[0068] One or more processors 102 and 202 may be referred to as a controller, microcontroller, microprocessor, or microcomputer. One or more processors 102 and 202 may be implemented by hardware, firmware, software, or a combination thereof, and the firmware or software may be configured to include modules, processes, or functions. Firmware or software configured to perform the functions, processes, suggestions, and / or methods disclosed in this disclosure may be included in one or more processors 102, 202, or stored in one or more memories 104, 204 for being driven by one or more processors 102, 202. The functions, processes, suggestions, and / or methods disclosed in this disclosure may be implemented using firmware or software in the form of code, commands, and / or command sets.

[0069] One or more memories 104 and 204 may be connected to one or more processors 102 and 202 and store various types of data, signals, messages, information, programs, code, commands, and / or instructions. One or more memories 104 and 204 may be located internally and / or externally to one or more processors 102 and 202. One or more memories 104 and 204 may be connected to one or more processors 102 and 202 via various technologies such as wired or wireless connections.

[0070] One or more transceivers 106 and 206 can transmit / receive user data, control information, and / or radio signals / channels mentioned in the methods and / or operation flowcharts disclosed herein to / from one or more other devices. Additionally, one or more processors 102, 202 can perform control such that one or more transceivers 106, 206 can transmit / receive user data, control information, or radio signals to / from one or more other devices. One or more transceivers 106 and 206 can be connected to one or more antennas 108 and 208. One or more transceivers 106 and 206 can be configured to transmit and / or receive user data, control information, and / or radio signals / channels mentioned in the functions, processes, suggestions, methods, and / or operation flowcharts disclosed herein via one or more antennas 108 and 208. In this disclosure, one or more antennas can be multiple physical antennas or multiple logical antennas (e.g., antenna ports). One or more transceivers 106 and 206 can convert received radio signals / channels, etc., from RF band signals to baseband signals so that the received user data, control information, radio signals / channels, etc., can be processed by one or more processors 102 and 202. For this purpose, one or more transceivers 106 and 206 may include (analog) oscillators and / or filters.

[0071] According to the example, the first wireless device 100 or UE may include a processor 102 and a memory 104 connected to the RF transceiver 106. The memory 104 may include at least one program for executing commands described below. FIG. 10 to FIG. 15 The described implementation involves operations related to the following methods. Specifically, the operations include attempting to detect synchronization blocks (SSBs) on specific frequency bands supporting terrestrial networks (TN) and non-terrestrial networks (NTN) and performing an initial access procedure based on the detected SSBs. In this case, based on the priorities set for TN and NTN cells, attempts to detect SSBs can be preferentially made on network cells with higher priority among TN and NTN cells.

[0072] In this disclosure, at least one memory 104 and 204 may store instructions or programs that, when executed, cause at least one processor 102 and 202 operatively coupled to at least one memory to perform operations according to some embodiments or implementations of this disclosure.

[0073] In this disclosure, a computer-readable (non-transitory) storage medium may store at least one instruction or computer program that, when executed by at least one processor, causes the at least one processor to perform operations according to some embodiments or implementations of this disclosure.

[0074] FIG. 3 An example of a frame structure used in a 3GPP-based wireless communication system is shown.

[0075] FIG. 3 The frame structure described is purely exemplary, and the number of subframes, time slots, and symbols within a frame can vary. In some wireless communication systems, different sets of OFDM parameters (e.g., subcarrier spacing (SCS)) can be configured for multiple cells aggregated for a single UE. Therefore, the (absolute time) duration of time resources comprising the same number of symbols (e.g., subframes, time slots, or transmission time intervals (TTI)) can be configured differently for the aggregated cells. Here, symbols can include OFDM symbols (or cyclic prefix-OFDM (CP-OFDM) symbols) and SC-FDMA symbols (or discrete Fourier transform-extended-OFDM (DFT-s-OFDM) symbols). In this disclosure, symbols, OFDM-based symbols, OFDM symbols, CP-OFDM symbols, and DFT-s-OFDM symbols are used interchangeably.

[0076] Reference FIG. 3 UL and DL transmissions are organized into frames. Each frame has a duration. And here, the basic unit of time is , And N f =4096. For reference, the sampling time is... , And N f,ref =2048. T c and T f Having a constant The relationship is as follows: A frame consists of 10 subframes, and the duration T of a single subframe is... sf The duration is 1 ms. Subframes are further divided into time slots, and the number of time slots in a subframe depends on the subcarrier interval. Each time slot may include a cyclic prefix (CP) based... The number of symbols. For example, in some scenarios, each time slot includes 14 OFDM symbols in a normal CP, and 12 OFDM symbols in an extended CP. The parameter set depends on the exponentially scalable subcarrier spacing. The following table shows the subcarrier spacing based on the normal CP. The number of OFDM symbols in each time slot ( ), the number of time slots per frame ( ) and the number of time slots in each subframe (N) ).

[0077] [Table 1]

[0078] The following table shows the distribution based on subcarrier spacing. The number of OFDM symbols in each time slot, the number of time slots in each frame, and the number of time slots in each subframe.

[0079] [Table 2]

[0080] For the subcarrier spacing configuration u, the time slots can be indexed in ascending order within the subframe as follows: And the following indexing within the frame in ascending order: .

[0081] In the following description, embodiments of this disclosure will be referred to as time slots by the term "minimum time unit" used for scheduling uplink, downlink, and sidelink transmissions. However, depending on the wireless communication system, the minimum time unit used for scheduling may be referred to by different terms. For example, in LTE-based systems, the minimum time unit used for scheduling transmissions is called a subframe or transmission time interval (TTI), while in NR-based systems, the minimum time unit used for scheduling is called a time slot.

[0082] FIG. 4 An example of a resource grid with time slots is shown. A time slot comprises multiple slots in the time domain (e.g., ...). (Number) symbols. For each parameter set (e.g., subcarrier spacing) and carrier, a Common Resource Block (CRB) is defined from the signaling of higher layers (e.g., Radio Resource Control (RRC) signaling). The beginning Subcarriers and A resource grid of OFDM symbols. Here, It represents the number of resource blocks (RBs) in the resource grid, and the subscript x is DL for downlink and UL for uplink. This refers to the number of subcarriers per RB, and in 3GPP-based wireless communication systems, Typically 12. For a given antenna port. p Subcarrier spacing configuration u A resource grid exists between the transmission link (DL or UL). Configuration is based on subcarrier spacing. u carrier bandwidth Provided to the UE by higher-layer parameters (e.g., RRC parameters). For the antenna port. p and subcarrier spacing configuration u Each element in the resource grid is called a resource element (RE), and a complex number symbol can be mapped to each RE. Each RE in the resource grid is indexed in the frequency domain. k and an index representing the sign position relative to a reference point in the time domain. l Uniquely identified. RBs are classified as CRBs and Physical Resource Blocks (PRBs). Configuration for subcarrier spacing. u CRBs are numbered from 0 upwards in the frequency domain. This is for subcarrier spacing configuration. u The center of subcarrier 0 of CRB 0 is equal to "point A", which serves as a common reference point for the RB grid. Subcarrier spacing configuration. u The PRB is defined within the bandwidth portion (BWP) and ranges from 0 to... Number, where i is the BWP number. PRBn in BWP i PRB With CRB The relationship between them is given by the following formula: ,in It is the CRB that starts with BWP relative to CRB 0. BWP includes multiple consecutive RBs in the frequency domain. For example, BWP can be a given set of parameters u in BWP i for a given carrier. i A subset of defined consecutive CRBs. A carrier may include up to N (e.g., 5) BWPs. A UE may be configured to have one or more BWPs on a given component carrier. Data communication is performed through the active BWPs, and only a predetermined number of BWPs (e.g., one BWP) configured for the UE can be active on the corresponding carrier.

[0083] In a 3GPP-based system, a control resource set (CORESET) can be defined and / or configured, which is a set of time-frequency resources that the UE can monitor for PDCCH. One or more CORESETs can be configured for the UE. A CORESET has a duration of one to three OFDM symbols and includes a set of physical resource blocks (PRBs). The PRBs constituting the CORESET and the CORESET duration can be provided to the UE via upper-layer (e.g., RRC) signaling. Within the configured CORESET, a set of PDCCH candidates is monitored according to the corresponding search space set. In this disclosure, monitoring means decoding each PDCCH candidate according to the monitored DCI format (so-called blind decoding). The Master Information Block (MIB) on the PBCH provides the UE with parameters (e.g., CORESET#0 configuration) for monitoring the PDCCH to schedule the PDSCH carrying System Information Block 1 (SIB1). The PBCH can also indicate that there is no associated SIB1, in which case the UE can be instructed to search for SSBs associated with SIB1 on other frequencies, as well as frequency ranges assuming no SSBs associated with SSB1. CORESET#0 (which is used to schedule at least SIB1 CORESET) can be configured via MIB or dedicated RRC signaling.

[0084] The set of PDCCH candidates monitored by the UE is defined based on the PDCCH search space set. The search space set can be a common search space (CSS) set or a UE-specific search space (USS) set. Each CORESET configuration is associated with one or more search space sets, and each search space set is associated with one CORESET configuration.

[0085] FIG. 5 Multi-beam operation in a 3GPP-based system is illustrated.

[0086] 5G and subsequent 3GPP-based systems can utilize high and ultra-high frequency bands (such as millimeter bands equal to or greater than 6 GHz) to transmit data to multiple users while maintaining high data rates through the use of wideband. However, millimeter bands have frequency characteristics that cause very rapid signal attenuation with distance due to the use of excessively high frequency bands. Therefore, when using frequency bands of at least 6 GHz or higher, 3GPP-based systems employ narrow-beam transmission schemes. These schemes address the reduced coverage caused by rapid propagation attenuation by concentrating energy in a specific direction rather than omnidirectionally, and perform signal transmission to compensate for the rapid propagation attenuation characteristics. However, when only one narrow beam is used to provide service, the service range that a single BS can provide is narrowed. Therefore, the BS collects multiple narrow beams and provides service by using a wideband.

[0087] FIG. 6 An example of sending SS / PBCH blocks on a cell is shown.

[0088] In 3GPP-based systems, each SSB is associated with each beam. For example, during a half-frame, different SSBs can be transmitted in different spatial directions (using different beams spanning the coverage area of ​​the cell). The possible temporal position of an SSB within a half-frame is determined by the subcarrier spacing, and the period of the half-frame for transmitting the SSB is configured by the network. Multiple SSBs can be transmitted within the frequency span of a carrier. Different indices of SSBs transmitted / detected on a single cell can correspond to different BS (wide) Tx beams. In 3GPP-based systems, multi-beam operation is based on beam switching / beam scanning, where signals are transmitted / received while the beam direction changes over time. For example, assuming a BS supports up to N transmit beams, beam scanning can be performed to transmit a synchronization signal block (SSB) including PSS, SSS, and PBCH in each of up to N beam directions (see [link to relevant documentation]). FIG. 5 (SSB beam scanning in the context of beam scanning). The set of SSBs within a beam scan is specifically referred to as the SS burst set or SS burst. The number of SSBs in the SS burst set represents the number of beams used for beam scanning. Multiple SSB modes are defined based on frequency bands and subcarrier spacing (SCS). In this disclosure, SSB modes are also referred to as SSB timing modes. For a half-frame with SSBs, the first (OFDM) symbol index s for a candidate SSB can be determined according to the SCS of the SSB as follows, where index 0 corresponds to the first symbol of the first time slot in the half-frame. In some scenarios, the SSB modes according to the following table can be used.

[0089] [Table 3]

[0090] In the table above, FR represents the frequency range. For example, FR1 could correspond to a frequency range of 410 MHz to 7125 MHz, and FR2 could correspond to a frequency range of 24250 MHz to 52600 MHz. As can be seen from the table, the number of SSBs within an SSB burst set can vary depending on the frequency range and the SCS. The number of candidate SSBs in a half-frame can be ordered in ascending time from 0 to... -1 is added to the index. If L max If it is the maximum number of SSB indexes within the cell or the maximum number of SSBs transmitted within half a frame, then it applies to operations without shared spectrum channel access. For operations with shared spectrum channel access, and L maxThey can be different. For example, in the case of shared spectrum channel access in FR1, for... SSB for SCS at 10 and 15 kHz, and for For SSCs of 20 and 30 kHz, the SSB can be defined as L. max =8.

[0091] SSBs are transmitted periodically from 5 ms to 160 ms. A UE performing initial access to the network assumes 20 ms (e.g., 2 frames). In other words, for initial cell access, the UE can assume that half-frames with SSBs occur in a two-frame period.

[0092] Return to reference FIG. 5 The UE can measure the power of SSBs received from the BS transmit (Tx) beam using a wide receive (Rx) beam and select its preferred beam. For example, the UE can select an SSB from among the detected / received SSBs. 3GPP-based systems specify a particular mapping between SSBs and Random Access Channel (RACH) timings to allow the network to know which beam the UE has selected. RACH timings are time and frequency resources available for transmitting RACH preambles. Information about how many SSBs will be mapped to a RACH timing and how many preamble indices will be mapped to a single SSB can be provided to the UE by the network. For example, when the network configures the number of SSBs per RACH timing to 1 / N, one SSB is associated with N RACH timings (where N is a positive integer), and when the network configures the number of SSBs per RACH timing to N, N preamble indices are mapped to a single SSB. The UE selects an SSB from among those detected / received by the UE on the cell and selects a RACH timing for transmission based on the selected SSB. The BS can detect which SSB is being transmitted on the cell already selected by the UE by utilizing BS Rx beam scanning to detect the RACH timing, including PRACH from the UE. The BS can then determine the BS Tx beam used for communication with the UE based on the SSB selected by the UE.

[0093] For finer beam tuning, CSI-RS can be transmitted. The BS can perform beamfining by using CSI-RS transmissions in a narrower beam around the BS Tx beam, determined based on the RACH timing of the detected PRACH from the UE (see [link to documentation]). FIG. 5(CSI-RS beam scanning in the BS Tx). The UE can measure the power of the CSI-RS received from the BS Tx narrow beam and report to the BS which BS Tx narrow beam the UE prefers. For example, the UE can measure the CSI-RS on a CSI-RS resource to select at least one CSI-RS resource and report the CSI-RS Resource Indicator (CRI) and the corresponding Reference Signal Received Power (RSRP) of the selected CSI-RS resource to the BS. The BS can determine the BS Tx narrow beam based on the CRI and / or the corresponding RSRP reported by the UE and repeatedly transmit CSI-RS with the BS Tx narrow beam (see [link to documentation]). FIG. 5 The P3 CSI-RS beam scan in the UE enables the UE to perform an Rx beam scan to find the appropriate UE Rx beam. The UE can find the appropriate UE Rx beam by measuring the power of the CSI-RS received from each UE Rx beam.

[0094] A UE can detect beam faults using CSI-RS / SSB. For example, when the L1-RSRP of the beam to be connected falls below a certain limit, the UE identifies the beam fault and searches for other candidate beams with good quality. If a predetermined number of beam faults are detected, a beam fault recovery (BFR) procedure can be triggered using the candidate beams. The network can provide the UE with the identifier (ID) of the SSB sent by the cell to determine the candidate beams for BFR, as well as the preamble index used when performing BRF to select the candidate beam identified by the SSB. When a predetermined number of beam faults are detected, the UE sends a BRF request to the network by sending a PRACH associated with the SSBID, and the network provides a random access response (RAR) to the UE in response to the BRF request.

[0095] When receiving a PDSCH, the UE can assume that the DM-RS port of the PDSCH is quasi-co-located (QCL) with the associated SSB in terms of Doppler shift, Doppler spread, average delay, delay spread, and spatial Rx parameters. Transmission Configuration Indicator (TCI) states can be configured / indicated for the PDCCH / PDSCH. TCI states can include quasi-co-location (QCL) information. For example, to decode a PDSCH based on a detected PDCCH with DCI for a given serving cell, the UE can be configured with M TCI states provided by the BS via upper-layer parameters. Each TCI state includes parameters configuring one or two downlink reference signals (DLRS) with the QCL relationship between the DM-RS port of the PDSCH, the DM-RS port of the PDCCH, or the CSI-RS port of the CSI-RS resource. The QCL relationship is configured by upper-layer parameter qcl-type1 for the first DLRS and upper-layer parameter qcl-type2 (if configured) for the second DLRS. The QCL type corresponding to each DL RS is given by the upper-level parameter qcl-type in QCL-Info, and can take one of the following values.

[0096] - “typeA”: {Doppler frequency shift, Doppler spread, average delay, delay spread}

[0097] - "typeB": {Doppler shift, Doppler spread}

[0098] - "typeC": {Doppler shift, average delay}

[0099] - "typeD": {space Rx parameter}

[0100] FIG. 7 An example of a non-terrestrial network (NTN) structure is shown.

[0101] Recently, there has been discussion about enabling 3GPP-based systems to support non-terrestrial networks (NTNs). NTNs are any network that includes non-terrestrial flying objects. When wireless communication via NTNs becomes possible in 3GPP-based systems, the continuity of wireless communication services can be ensured, the reliability of wireless communication services can be enhanced through connectivity between various access technologies, and network resilience and reliability in the face of disasters can be improved. For ease of explanation, the following terminology will be used.

[0102] - NTN: The radio access network including the BS, which provides non-terrestrial radio access to the UE by using NTN payloads and NTN gateways installed in the air or on space-based NTN vehicles.

[0103] - NTN Gateway: A ground station located on the Earth's surface that provides connectivity to NTN payloads via a feeder link. An NTN gateway is a Transport Network Layer (TNL) node.

[0104] - NTN payload: A network node installed on a satellite or high-altitude platform station to provide connectivity between the service link and the feeder link.

[0105] - Service Link: The radio link between the NTN payload and the UE.

[0106] - Feeder link: The wireless link between the NTN gateway and the NTN payload.

[0107] - Satellite: A space vehicle that carries NTN payloads and orbits the Earth.

[0108] - NTN cell: A cell that provides a service link between the UE and the NTN payload.

[0109] Reference FIG. 7 The NTN gateway connects to the NTN payload installed on a satellite or High Altitude Platform System (HAPS) via a feeder link. The NTN payload connects to the UE via a serving link. The NTN gateway can connect to the core network of a 3GPP-based system.

[0110] NTN payloads forward radio protocols received from the UE (via the serving link) to the NTN gateway (via the feeder link), and forward radio protocols received from the NTN gateway (via the feeder link) back to the UE (via the feeder link). An NTN gateway can serve multiple NTN payloads, and NTN payloads can be served by multiple NTN gateways. For NTN, the tracking area can correspond to a fixed geographical area, and each mapping can be configured in the radio access network.

[0111] The following three types of service links are supported: - Fixed Earth service link: A service link provided by a beam that continuously covers the same geographic area (e.g., in the case of GSO satellites).

[0112] - Quasi-Earth Fixed Service Link: A service link provided by a beam that covers one geographic area for a limited time period and another geographic area for a different time period (e.g., in the case of NGSO that generates a steerable beam).

[0113] - Earth mobile service links: Service links whose coverage area is provided by beams that slide across the Earth's surface (e.g., for NGSO satellites that generate fixed or unmanipulated beams).

[0114] NTN can include satellite communication networks, air-to-ground networks, and UAV networks. One of the key concepts of NTN is that NTN cells are provided by non-geostationary orbit (NGSO) satellites that periodically orbit the Earth. Each satellite has its own orbit, which is contained in satellite position estimation information. Based on the satellite position estimation information, the network can predict feeder link handovers and manage UE mobility and radio resource control. The BS providing NTN access can broadcast orbital trajectory information or ephemeris information about the coordinates of the NTN payload. Ephemeris information can provide satellite position estimates in the format of position and velocity state vectors or in the format of orbital parameters. The following shows a description of the EphemerisInfo information element and fields broadcast by the BS.

[0115] [Table 4]

[0116] [Table 5]

[0117] Satellite communication networks can include low Earth orbit (LEO) satellites, medium Earth orbit (MEO) satellites, and geostationary orbit (GEO) satellites.

[0118] [Table 6]

[0119] The following is an example of an NTN deployment scenario.

[0120] [Table 7]

[0121] FIG. 8 Examples of synchronization grids and channel grids used in some implementations are shown.

[0122] A UE attempting network access performs a cell search, which is the process by which the UE obtains time and frequency synchronization with the cell and detects the cell's Physical Layer Cell Identifier (PCI). During a cell search operation performed at power-on, the UE obtains the necessary information for cell access by using the SSB. The UE performing the cell search attempts to detect the SSB as it moves through the frequency domain, assuming a synchronization grid. When no explicit signaling for the SSB location exists, the synchronization grid indicates the possible frequency location of the SSB that the UE will use to obtain system information. In LTE, the frequency domain location of the PSS / SSS is always fixed near the carrier center frequency (see [link to LTE]). FIG. 8(a)). In contrast, in NR, a set of possible frequency locations for the SSB is defined based on the frequency band, called the synchronization grid, and the UE needs to search for the SSB based on this synchronization grid. Unlike LTE, where the UE searches for the PSS / SSS at all carrier grid locations, a sparser synchronization grid is defined for the UE in NR (see [reference]). FIG. 8 (b) Therefore, in NR, the UE needs to search for the SSB in a sparser synchronization grid compared to LTE. The carrier grid is also called the channel grid, and the channel grid represents the possible carrier locations. The global frequency channel grid defines a set of radio frequency (RF) frequencies F REF The RF reference frequency is used in signaling to identify the location of RF channels, SSB blocks, and other elements. A global frequency grid is used to define all frequencies from 0 to 100 GHz. In NR, the RF reference frequency can be given by the NR Absolute Radio Channel Number (NR-ARFCN) and is expressed in MHz as the RF reference frequency F. REF It can be given by the following equation: ,in It is the granularity of the frequency grid, N REF It is NR-ARFCN, and and The following table can be used to provide the information.

[0123] [Table 8]

[0124] The channel grid defines a subset of RF reference frequencies that will be used to identify the location of RF channels in the uplink and downlink.

[0125] A global synchronization grid is defined for all frequencies, and the frequency position of the SSB is defined as the SS with the corresponding digital global synchronization signal number (GSCN). REF GSCN and SS are defined for all frequency ranges. REF The parameters are defined, for example, in the table below.

[0126] [Table 9]

[0127] The synchronization grid for each frequency band can be given, for example, by the table below. The distance between applicable GSCN entries can be given by the <step size> indicated in the table below.

[0128] [Table 10]

[0129] The notes shown in Table 10 can be explained using the following table.

[0130] [Table 11]

[0131] Referring to Tables 9 and 10, for n35, the UE can perform cell search by incrementing the GSCN by 1 starting from GSCN=6125.

[0132] Cell selection is performed based on the SSB defined in the cell containing the synchronization grid (CD-SSB). An SSB is called a CD-SSB when it is associated with Residual Minimum System Information (RMSI) (e.g., SIB1), for example, when the MIB carried by the PBCH in the SSB includes parameters for the transmission of the PDCCH against the scheduling RMSI. The UE can search for frequency bands, identify the strongest cell based on the SSB for each carrier frequency, and select a cell to perform initial access.

[0133] SSB related operations

[0134] FIG. 9 An example of the SSB structure is shown. The UE can perform cell search, system information acquisition, beam alignment for initial access, DL measurements, etc., based on the SSB. The SSB can be used interchangeably with the Synchronization Signal / Physical Broadcast Channel (SS / PBCH) block.

[0135] Reference FIG. 9 The SSB comprises the PSS, SSS, and PBCH. The SSB consists of four consecutive OFDM symbols, and for each OFDM symbol, the PSS, PBCH, SSS / PBCH, and PBCH are transmitted. The PSS and SSS each consist of one OFDM symbol and 127 subcarriers, and the PBCH consists of three OFDM symbols and 576 subcarriers. Polar coding and Quadrature Phase Shift Keying (QPSK) are applied to the PBCH. The PBCH includes data REs and demodulation reference signals (DMRS) REs for each OFDM symbol. For each RB, there are three DMRS REs, and three data REs exist between the DMRS REs.

[0136] Cell search refers to the process by which a UE obtains time / frequency synchronization for a cell and detects the cell identifier (ID) (e.g., physical layer cell ID or PCID) of that cell. The PSS is used to detect cell IDs within a cell ID group, and the SSS is used to detect cell ID groups. The PBCH is used to detect the SSB (time) index and detect half-frames.

[0137] The UE's cell search process can be summarized in Table 12 below.

[0138] [Table 12]

[0139] There are 336 cell ID groups, and each cell ID group contains 3 cell IDs. There are a total of 1008 cell IDs. Information about the cell ID group to which a cell ID belongs is provided / obtained through the cell's SSS (Social Security Service), and information about the cell IDs within the 336 cells of that cell ID group is provided / obtained through the PSS (Position Support Service).

[0140] FIG. 10 This is a diagram showing the signal flow for the PDCCH transmission and reception process.

[0141] Reference FIG. 10 The BS can send control resource set (CORESET) configuration to the UE (S502). A CORESET is defined as a set of resource element groups (REGs) with a given set of parameters (e.g., SCS or CP length). A REG is defined as one OFDM symbol multiplied by one (P)RB. Multiple CORESETs for a single UE can overlap in the time / frequency domain. A CORESET can be configured via system information (e.g., Master Information Block (MIB)) or higher-layer signaling (e.g., Radio Resource Control (RRC) signaling). For example, configuration information for a specific common CORESET (e.g., CORESET#0) can be sent in the MIB. For example, a PDSCH carrying System Information Block 1 (SIB1) can be scheduled via a specific PDCCH, and CORESET#0 can be used to carry the specific PDCCH. Configuration information for CORESET#N (e.g., N>0) can be sent via RRC signaling (e.g., cell-wide RRC signaling or UE-specific RRC signaling). For example, UE-specific RRC signaling carrying CORSET configuration information may include various forms of signaling, such as RRC configuration messages, RRC reconfiguration messages, and / or BWP configuration information. Specifically, CORSET configuration may include the following information / fields.

[0142] - controlResourceSetId: Represents the ID of CORESET.

[0143] - frequencyDomainResources: Represents the frequency resources of CORESET. The frequency resources of CORESET are represented as a bitmap, where each bit corresponds to an RBG (e.g., six (contiguous) RBs). For example, the most significant bit (MSB) of the bitmap corresponds to the first RBG. The RBG corresponding to the bit configured as 1 is allocated as the frequency resource of CORESET.

[0144] - Duration: Represents the time resource of the CORESET. Duration represents the number of consecutive OFDM symbols contained in the CORESET. Duration has a value between 1 and 3.

[0145] - cce-REG-MappingType: Indicates the control channel element (CCE) -REG mapping type. Interleaved and non-interleaved types are supported.

[0146] - interleaverSize: Indicates the size of the interleaver.

[0147] - pdcch-DMRS-ScramblingID: Represents the value used for PDCCH DMRS initialization. When pdcch-DMRS-ScramblingID is not included, the physical cell ID of the serving cell is used.

[0148] - precoderGranularity: Indicates the precoder granularity in the frequency domain.

[0149] - reg-BundleSize: Indicates the REG bundle size.

[0150] - tci-PresentInDCI: Indicates whether the DL-related DCI includes the Transport Configuration Index (TCI) field.

[0151] - tci-StatesPDCCH-ToAddList: Represents a subset of TCI states configured in pdcch-Config for providing the quasi-co-address (QCL) relationship between the DL RS (TCI-State) and the PDCCH DMRS port of the RS set.

[0152] The BS can send the PDCCH search space (SS) configuration to the UE (S504). The PDCCH SS configuration can be sent via higher-layer signaling (e.g., RRC signaling). For example, RRC signaling can include, but is not limited to, various signaling such as RRC establishment messages, RRC reconfiguration messages, and / or BWP configuration information. Although in FIG. 1 Examples of CORESET and PDCCH SS configurations are shown, but in FIG. 5 For ease of explanation, the CORESET configuration and PDCCH SS configuration are separately notified by signals, and this disclosure is not limited thereto. For example, the CORESET configuration and PDCCH SS configuration can be sent in a single message (e.g., via an RRC signaling) or separately in different messages.

[0153] The PDCCH SS configuration can include information about the configuration of the PDCCH SS set. A PDCCH SS set can be defined as a set of PDCCH candidates monitored by the UE (e.g., blind detection). One or more SS sets can be configured for the UE. Each SS set can be a USS set or a CSS set. For convenience, the PDCCH SS set can be referred to as "SS" or "PDCCH SS".

[0154] The PDCCH SS set includes PDCCH candidates. PDCCH candidates are the CCEs that the UE monitors to receive / detect the PDCCH. Monitoring includes blind decoding (BD) of the PDCCH candidates. Depending on the aggregation level (AL), a PDCCH (candidate) includes 1, 2, 4, 8, or 16 CCEs. A CCE includes six REGs. Each CORESET configuration is associated with one or more SSs, and each SS is associated with one CORESET configuration. An SS is defined based on an SS configuration, and the SS configuration may contain the following information / fields.

[0155] - searchSpaceId: Represents the ID of SS.

[0156] - controlResourceSetId: Represents the CORESET associated with SS.

[0157] - monitoringSlotPeriodicityAndOffset: Indicates the period (slot) and offset (slot) for PDCCH monitoring.

[0158] - monitoringSymbolsWithinSlot: Represents the first OFDM symbol for PDCCH monitoring within the slot configured for PDCCH monitoring. The first OFDM symbol for PDCCH monitoring is represented as a bitmap, where each bit corresponds to an OFDM symbol for the slot. The MSB of the bitmap corresponds to the first OFDM symbol for the slot. The OFDM symbol corresponding to a bit configured to 1 corresponds to the first symbol of the CORESET within the slot.

[0159] - nrofCandidates: Represents the number of PDCCH candidates for each AL, where AL = {1, 2, 4, 8, 16} (one of the values ​​0, 1, 2, 3, 4, 5, 6, and 8).

[0160] - searchSpaceType: Indicates whether to use the Common Search Space (CSS) or the Specific Search Space (USS), and the DCI format used for the corresponding SS type.

[0161] Then, the BS can generate and send a PDCCH to the UE (S506), and the UE can monitor PDCCH candidates in one or more SSs to receive / detect PDCCH (S508). The timing of the UE monitoring PDCCH candidates (e.g., time / frequency resources) is defined as the PDCCH (monitoring) timing. One or more PDCCH (monitoring) timings can be configured in a time slot.

[0162] Table 13 shows the characteristics of each SS.

[0163] [Table 13]

[0164] Table 14 shows the DCI format transmitted on the PDCCH.

[0165] [Table 14]

[0166] DCI format 0_0 can be used to schedule PUSCH based on TB (or TB level), and DCI format 0_1 ​​can be used to schedule PUSCH based on TB (or TB level) or PUSCH based on code block group (CBG) (or CBG level). DCI format 1_0 can be used to schedule PDSCH based on TB (or TB level), and DCI format 1_1 can be used to schedule PDSCH based on TB (or TB level) or PDSCH based on CBG (or CBG level). DCI format 2_0 can be used to forward dynamic slot format information (e.g., dynamic SFI) to the UE, and DCI format 2_1 can be used to forward downlink pre-occupancy information to the UE. DCI format 2_0 and / or DCI format 2_1 can be forwarded to UEs in the corresponding group via a group common PDCCH, which is the PDCCH delivered to UEs defined as a group.

[0167] DCI formats 0_0 and 1_0 are called fallback DCI formats, while DCI formats 0_1 and 1_1 are called non-fallback DCI formats. In fallback DCI formats, the DCI size / field configuration remains the same regardless of the UE configuration. On the other hand, the DCI size / field configuration changes based on the UE configuration in non-fallback DCI formats.

[0168] FIG. 11 The example illustrates the coexistence of terrestrial networks (TN) and non-terrestrial networks (NTN).

[0169] Reference FIG. 11When the UE is served by a BS of the TN, the UE's receive (RX) beam can be pointed to the ground, and when the UE is served by a BS of the NTN, the UE's RX beam can be pointed to the sky. For frequency bands where NTN and TN can coexist, the UE can perform initial access with at least one of the NTN and TN. For example, the UE can detect the SSB of a cell for the NTN in the frequency band and perform an initial access procedure with the cell for the NTN, and after the initial access procedure with the NTN, detect the SSB of a cell for the TN and perform an initial access procedure with the cell for the TN based on the detected SSB.

[0170] In the following text, assuming that the UE has completed the initial access procedure with at least one of the TN and NTN cells based on the above method, the method of switching the UE's signal transmission and reception cell from the TN cell to the NTN cell or vice versa based on the DCI received from the TN or NTN cell will be described in detail.

[0171] NTN mode, TN mode and default mode

[0172] FIG. 12 This is a diagram illustrating a method by which a UE receives data or signals from a TN or NTN cell.

[0173] As described above, the UE can connect to both the NTN and TN cells via the initial access procedure based on SSB detection. In this case, the UE can perform data transmission and reception with the TN cell at an improved speed, and with the NTN cell to ensure wide coverage. Alternatively, the UE can provide / support multiple services (such as eMBB / URLLC services) through data transmission and reception with the TN cell, and can receive multicast-related services through data transmission and reception with the NTN cell. Even if the UE connects to both the NTN and TN cells, the UE can also transmit and receive data only for the TN cell or the NTN cell.

[0174] For details, refer to FIG. 12 The UE can transmit and receive data or signals with respect to the TN cell from time slot #0 (or subframe #0) to time slot #2. The UE can transmit and receive data or signals with respect to the NTN cell from time slot #3 to time slot #5, and can again transmit and receive data or signals with respect to the TN cell in time slot #6. The UE can also transmit and receive data or signals with respect to the NTN cell in time slot #8. In this way, the UE can transmit and receive data with respect to either the NTN or TN cell while connected to both the TN and NTN cells.

[0175] The UE can support both TN mode for transmitting and receiving data / signals based on TN cells and NTN mode for transmitting and receiving data / signals based on NTN cells. The UE can transmit and receive data / signals based on either TN mode or NTN mode, whichever is configured as the default mode. For example, a UE with TN mode activated or a TN-based UE can receive data / signals from or transmit data / signals to a TN cell. Alternatively, a UE with NTN mode activated or a NTN-based UE can receive data / signals from or transmit data / signals to an NTN cell.

[0176] The UE can configure either TN mode or NTN mode as the default mode. The UE can send and receive data / signals based on the default mode configured above, and can also switch to a non-default mode, which is a mode between TN and NTN modes that is not configured as the default. First, the method for determining the default and non-default modes in TN and NTN modes is described in detail.

[0177] The UE can be configured to configure or determine the default mode in TN mode and NTN mode according to at least one of the following methods: Alternative Scheme 1, Alternative Scheme 2, Alternative Scheme 3 and Alternative Scheme 4.

[0178] (1) Alternative option 1

[0179] The default mode is always configured as TN mode, and a non-default mode can be configured as NTN mode (Alternative Option 1-1). Alternatively, the UE can configure / determine either TN mode or NTN mode as the default mode during the initial access procedure for TN and NTN cells (Alternative Option 1-2). For example, the UE can determine the default mode based on the quality of the SSB detected for each of the TN and NTN cells. For example, when the quality of the SSB for the TN cell is higher than the quality of the SSB for the NTN cell, the UE can determine TN mode as the default mode. Alternatively, the UE can determine the default mode based on the order in which the initial access procedure is performed. For example, when the UE performs the initial access procedure for the TN cell after performing the initial access procedure for the NTN cell, the default mode can be determined as NTN mode.

[0180] (2) Alternative option 2

[0181] The UE can be instructed / configured to select a default mode between TN and NTN modes via RRC signaling. For example, the UE can receive configuration information for RRC parameters for TN and NTN modes, and can be explicitly indicated which of the two modes is the default mode through separate indication information included in the configuration information.

[0182] When the default mode is not configured via RRC signaling, the UE can determine the default mode according to the above alternative scheme 1.

[0183] (3) Alternative option 3

[0184] The UE can directly determine the default mode between TN and NTN modes. For example, the UE can determine the preferred mode between NTN and TN modes as the default mode based on the quality of the TN cell and the quality of the NTN cell, or the type of service to be provided. In this case, the UE can report a default mode indicator indicating the determined default mode to the BS, and the BS can send an acknowledgment message for the default mode to the UE based on the default mode indicator.

[0185] (4) Alternative option 4

[0186] The UE can be instructed via DCI to select either TN mode or NTN mode as the default mode. In other words, the default mode can be dynamically indicated to the UE via DCI. For example, the UE can be instructed via DCI to select the default mode for rollback operations.

[0187] The following describes in detail a method for dynamically switching a UE from a default mode to a non-default mode or from a non-default mode to a default mode based on indication information.

[0188] Dynamic mode switching between NTN and TN

[0189] As described above, the UE can connect to TN and NTN cells through initial access procedures and other means (RRC connection) in frequency bands where NTN and TN cells coexist, and can send and receive data / signals based on TN mode or NTN mode.

[0190] Specifically, the UE can be configured with specific parameters (or RRC parameters) for TN mode and specific parameters (or RRC parameters) for NTN mode. Here, specific parameters may include parameters for parameter sets, time slot structures (e.g., time slot formats), TCI states, etc., which are RRC parameters configured via RRC signaling.

[0191] The UE can transmit and receive data about a TN cell in TN mode based on specific parameters for that TN cell. Alternatively, the UE can transmit and receive data about an NTN cell in NTN mode based on specific parameters for that NTN cell. As described above, the UE can transmit and receive data / signals in either TN or NTN mode, and can transmit and receive data / signals in both TN and NTN modes simultaneously.

[0192] The UE can receive downlink control information (DCI) from either a TN cell or an NTN cell. This downlink control information may also include indication information (NTN / TN indication (NTI)) indicating a handover between TN and NTN modes. The UE can switch from TN mode to NTN mode, or perform a handover from NTN mode to TN mode, based on the reception of a DCI including the NTI.

[0193] The UE can set / request a specific time interval T for mode switching between NTN and TN modes. gap Here, a specific time interval T can be configured based on the following: gap The specific time interval T can be configured differently depending on whether the handover is from TN to NTN mode or from NTN to TN mode. This includes the application or change of specific parameters for the TN / NTN mode switch, the change of the Tx / Rx beam corresponding to each mode (e.g., TN mode facing the ground, NTN mode facing the sky), and the processing time. gap For example, a specific time interval may include a first time interval T for the handover configuration from TN mode to NTN mode. gap,1 And the second time interval T for the switching configuration from NTN mode to TN mode. gap,2 Here, the first time interval can have a different duration than the second time interval. For example, the first time interval T... gap,1 It can be configured to be greater than the second time interval T gap,2 The value of .

[0194] A specific time interval T can be configured in units of time slots, symbols, or subframes. gap For example, the first time interval T gap,1 It can be configured with n1 time slots, and the second time interval T gap,2 It can be configured to have n² time slots.

[0195] In the following text, it is assumed that parameters have been configured for each mode in the UE as described above, and a specific time interval T has been configured. gap And this was explained in detail.

[0196] FIG. 13 and FIG. 14 This diagram is used to explain the method by which a UE switches modes based on received downlink control information.

[0197] As described above, the UE can configure either TN mode or NTN mode as the default mode. Here, the default mode can be predefined as described above or indicated by RRC signaling, etc. In this case, the UE can send and receive data / signals based on the default mode, unless there is a separate indication via indication information (such as the mode switching mentioned above).

[0198] Reference FIG. 13 The UE can receive configuration information including a first RRC parameter for TN and a second RRC parameter for NTN (S131). The UE can transmit and receive data / signals by using the RRC parameter corresponding to the default mode among the first and second RRC parameters. For example, when the default mode is configured as TN mode based on a TN cell, the UE can transmit and receive data / signals based on the first RRC parameter. Alternatively, when the default mode is configured as NTN mode based on an NTN cell, the UE can transmit and receive data / signals based on the second RRC parameter.

[0199] The UE can monitor the PDCCH based on the default mode (S133). For example, when the default mode is TN mode, the UE can monitor whether a PDCCH is received from a TN cell.

[0200] Then, the UE can receive a PDCCH (S135) including an NTN / TN indicator (NTI). The NTI included in the PDCCH can instruct the UE to activate either TN mode or NTN mode. For example, the UE can perform a switch from the default mode to a non-default mode or from a non-default mode to the default mode based on the NTI.

[0201] When NTI indicates TN mode, the UE can transmit and receive signals / data based on TN mode (S137). Alternatively, when NTI indicates NTN mode, the UE can transmit and receive signals / data based on NTN mode (S139).

[0202] When the current active mode differs from the mode indicated by the NTI, the UE can switch to the mode indicated by the NTI. Specifically, when the UE performs a mode switch according to the NTI's indication, the UE can change the RRC parameter corresponding to the mode to be switched to. For example, when the active mode is TN mode and the NTI indicates NTN mode, the UE can change the first RRC parameter to a second RRC parameter. Here, the first RRC parameter and the second RRC parameter can include at least one of the following parameters: - Parameter set (subcarrier spacing, cyclic prefix length) - Beam-related information (e.g., TCI status, QCL information, UL space-related information, etc.) - Antenna-related information (antenna number, RF antenna chain, antenna module, etc.) - Processing time capability - UE bandwidth Reference FIG. 14 The UE can switch from TN mode to NTN mode based on the reception of DCI including NTI, and then switch back from NTN mode to TN mode.

[0203] Specifically, the UE can transmit and receive data / signals based on the TN mode configured as the default mode. The UE can receive DCI including an NTI indicating the NTN mode based on the TN mode. In this case, the UE can perform operations for switching from TN mode to NTN mode (e.g., reconfiguring a first RRC parameter to a second RRC parameter), and when the first time interval T... gap,1 In the past, the UE could perform data / signal transmission and reception based on NTN mode. For example... FIG. 14 As shown, the UE can send and receive data / signals in NTN mode after receiving the NTI and after the first time interval has elapsed. In this case, even if time resources for TN mode are configured after receiving the NTI, the UE will not send or receive data / signals in the first time interval T. gap,1 During this period, data / signals are transmitted or received based on TN mode. That is, the UE can anticipate the first time interval T... gap,1 No data / signals will be sent or received during this period.

[0204] Then, the UE can receive a DCI including an NTI indicating the TN mode during data / signal transmission / reception based on NTN mode. In this case, as... FIG. 14 As shown, the UE can perform a handover to TN mode based on the reception of NTI. This can be done in the second time interval T. gap,2 Internal execution switches to TN mode, such as FIG. 14 As shown. The UE can receive the NTI and the second time interval T gap,2 Afterwards, data / signals are transmitted and received based on TN mode. In this case, even if time resources for NTN mode are configured after receiving NTI, the UE will transmit and receive data / signals in the second time interval T. gap,2 During this period, data / signal transmission / reception is not performed based on NTN mode. In other words, the UE can anticipate the second time interval T... gap,2 No data / signals will be sent or received during this period.

[0205] Alternatively, the UE can send and receive signals / data based on a non-default mode instead of the default mode via instructions such as NTI. In this case, the UE can receive an NTI indicating a switch to the default mode, or fall back to the default mode based on the expiration of a preset timer. For example, when TN mode is configured as the default mode and a switch to NTN mode (which is the non-default mode) is made via NTI, the UE can send and receive data / signals based on NTN mode until the preset timer expires, and when the preset timer expires, the UE can fall back to TN mode (which is the default mode).

[0206] FIG. 15 and FIG. 16 An example is given of a method for switching execution modes based on the NTI included in the DCI.

[0207] The NTI can be indicated to the UE via the DCI. The NTI can indicate either the TN mode or the NTN mode as described above. The UE can monitor the PDCCH for the DCI including the NTI based on the current active mode. The NTI can be indicated to the UE via at least one of Alternative Scheme 1, Alternative Scheme 2, or Alternative Scheme 3.

[0208] (1) Alternative Option 1: Based on Non-Scheduled DCI

[0209] The NTI can be indicated to the UE via a DCI with a common / group common DCI (GC-DCI) format. Here, the common / group common DCI format may not include scheduling information such as PDSCH.

[0210] Reference FIG. 15 The UE can receive GC-DCI including NTI. In this case, considering the transmission timing of the acknowledgment (ACK) for the reception of GC-DCI, the UE can apply the time interval T configured for mode switching via NTI. gap For example, when a GC-DCI including an NTI indicating mode switching is received in time slot n, the UE can send an ACK for the GC-DCI in time slot n+K. In this case, the UE can apply a time interval based on time slot n+K and from time slot n+K+T gap Signals / data are sent and received based on the pattern indicated by NTI.

[0211] (2) Alternative Option 2: Based on DCI scheduling

[0212] The NTI can be indicated to the UE via a DCI format that includes scheduling information for data / signals. For example, the NTI can be implicitly or explicitly indicated to the UE based on the DCI that schedules data channels such as PDSCH. Alternative scheme 2-1 describes the case where the NTI is explicitly indicated via DCI, and alternative schemes 2-2 and 2-3 describe the case where the NTI is implicitly indicated based on the RNTI, format, etc. of DCI.

[0213] 1) Alternative option 2-1

[0214] The UE can obtain the NTI value from the NTI field added to the DCI (Alternative Solution 2-1). For example, the UE can obtain the NTI value based on the contents of the remaining fields of the DCI.

[0215] 2) Alternative option 2-2

[0216] Alternatively, the UE can use different DCI formats between NTN and TN modes (see [link]). FIG. 10 (as shown in Table 14), and the indication for NTI can be implicitly derived based on the format of the received DCI (Alternative Scheme 2-2). For example, the UE can assume that when a DCI of a format not corresponding to the currently active mode is received, it indicates a switch to the mode corresponding to the DCI format. For example, DCI format A can be used for TN mode, and DCI format B can be used for NTN mode. In this case, the UE can receive the DCI based on the currently active TN mode, and when the received DCI is in format B, it can determine (implicitly) indicate a switch to NTN mode. In this case, the UE can predict that data scheduled by DCI format B can be sent based on NTN mode instead of TN mode, and can switch to NTN mode (or activate NTN mode) to receive the scheduled data.

[0217] 3) Alternative option 2-3

[0218] Alternatively, the UE can use different RNTIs between NTN and TN modes, and can (implicitly) indicate the NTI to the UE based on the RNTI used to scramble the CRC of the received DCI (Alternative Scheme 2-3). For example, the DCI for NTN mode can have a CRC scrambled with TN-RNTI, and the DCI for TN mode can have a CRC scrambled with NTN-RNTI. In this case, when a UE activated in TN mode receives a DCI with a CRC scrambled with NTN-RNTI, the UE can determine that a handover from TN mode to NTN mode has been implicitly indicated. That is, the UE can perform a handover to NTN mode upon receiving a DCI with a CRC scrambled with TN-RNTI, and receive data scheduled by the DCI based on the switched NRN mode.

[0219] 4) Application of time intervals

[0220] As described above, a UE activated in TN mode can receive DCI (including scheduling information) that implicitly / explicitly indicates NTI, and can apply time intervals to mode switching based on the DCI reception time (or time slot).

[0221] For details, refer to FIG. 16 A UE activated in TN mode can receive a DCI that implicitly / explicitly indicates the NTI in time slot n. The UE can then perform a handover to NTN mode based on the NTI confirmed by the DCI. In this case, the UE can apply a first time interval T based on the time slot n in which the DCI is received. gap1 For example, the UE can be in time slot n+T gap1 The system receives data scheduled by DCI based on NTN mode.

[0222] Fallback operation

[0223] FIG. 17 to FIG. 19 This diagram illustrates the method by which a UE performs a fallback operation between TN and NTN modes.

[0224] As described above, when transmitting or receiving data / signals in a non-default mode other than the default mode, the UE can perform a fallback operation to the default mode. The fallback operation can be performed based on a preset timer (Alternative Option 1), a mode activation time indicated by the DCI (Alternative Option 2), or an inactivity indicator (or mode termination indicator) indicated by the DCI (Alternative Option 3). The UE can switch to the default mode via the fallback operation, or by receiving an NTI indicating a switch to the default mode. In the following description, for ease of explanation, it is assumed that the TN mode is configured as the default mode and the NTN mode is configured as a non-default mode.

[0225] (1) Alternative option 1

[0226] When operating in a non-default mode, the UE can determine whether to perform a rollback operation to the default mode based on a preset timer.

[0227] For details, refer to FIG. 17 In TN mode, which is the default mode, the UE can receive an NTI indicating a switch to NTN mode. This occurs when the first time interval T has elapsed since the ACK for the NTI was sent. gap1 At this time, the UE can switch to NTN mode. The UE can switch to NTN mode based on the first time interval T. gap1 Then switch to NTN mode to send and receive data / signals. In this case, the time slot from which NTN mode is activated (i.e., from the time slot for sending ACK, past the first time interval T) can be used. gap1 The preset timer operates in subsequent time slots. When a DCI (Dispatch Instructions) for scheduled data / signals in NTN mode is received, the preset timer can be reset or reinitialized. For example, when the preset timer is a backoff counter that backs off in the first time interval, the preset timer starts from the time slot after the ACK is sent, after the first time interval T. gap1 Subsequent time slot operations may occur, and the first time slot may expire. When the UE receives DCI (Distributed Information Center) for scheduling data based on NTN mode before the preset timer expires, the preset timer can be reset or reinitialized to the first time slot. For example, when the preset timer is a counter that expires after the first time slot has elapsed, the preset timer starts from the time slot where the ACK is sent and the first time interval T has elapsed. gap1 Subsequent time slot operations can be performed and reinitialized either after the first time slot has elapsed or by receiving scheduling data via DCI.

[0228] When the preset timer expires, the UE can perform a fallback from the non-default mode (NTN mode) to the default mode (TN mode). For example, the UE can perform a fallback from the non-default mode (NTN mode) to the default mode (TN mode) after the preset timer expires in the second time interval T. gap2 Within this timeframe, a rollback to TN mode is executed. In other words, after the second time interval T has elapsed since the preset timer expired... gap2 At this time, the UE can roll back / switch to the default mode (TN mode).

[0229] For reference FIG. 16 As described, a first time interval T can be applied based on the time slot of the received DCI, including the NTI. gap1 .

[0230] (2) Alternative option 2

[0231] When operating in the aforementioned non-default mode, the UE can base its operation on the mode activation time T indicated by the DCI.act Determine whether to perform a fallback operation to the default mode. Specifically, the UE may receive a DCI including an NTI indicating a switch from the default mode (TN mode) to a non-default mode. In addition to the NTI, the DCI may also include information about the mode activation time T. act Information. The UE can be based on the mode activation time T. act Determine the activation time of the non-default mode indicated by the NTI. The mode activation time T can be updated by receiving additional DCI signals. act .

[0232] For details, refer to FIG. 18 The UE can receive DCI, including information about the NTI and mode activation time, based on the TN mode, which is the default mode. Based on the received DCI, the UE can switch to NTN mode, a non-default mode indicated by the NTI. For example, after a first time interval has elapsed from the slot where the ACK for the DCI was sent (i.e., the switch to a non-default mode is complete), the UE can switch to NTN mode, a non-default mode indicated by the NTI. The UE can receive DCI at the mode activation time T. act NTN mode is activated during this period. When the mode is activated for time T... act In the past, the UE could perform a rollback operation to switch back to TN mode, which was the default mode. For example, when the mode was active for time T... act After the second time interval has elapsed, the UE can roll back / switch to NTN mode.

[0233] For reference FIG. 16 As described, a first time interval T can be applied based on the time slot of the received DCI, including the NTI. gap1 .

[0234] (3) Alternative option 3

[0235] When operating in non-default mode, if a DCI or MAC CE including a deactivation indication or a mode termination indication is received, the UE can perform a fallback operation from non-default mode to default mode. The UE can send and receive signals / data based on non-default mode until a DCI or MAC CE including an inactivity indicator or a mode termination indication is received.

[0236] Reference FIG. 19The UE can receive a DCI including an NTI based on the TN mode, which is the default mode, and the NTI indicates a switch to the NTN mode, which is the non-default mode. The UE can switch to the NTN mode indicated by the NTI based on the reception of the DCI. For example, the UE can switch to the NTN mode indicated by the NTI after a first time interval has elapsed since the time slot for sending an ACK for the DCI was sent. The UE can remain in NTN mode until it receives a DCI including a deactivation indicator or a mode termination indicator based on the NTN mode. When a DCI including an inactivity indicator or a mode termination indicator is received based on the NTN mode, the UE can perform a fallback operation to switch back to the TN mode, which is the default mode. For example, after completing the reception of a DCI or MAC CE including an inactivity indicator or a mode termination indicator, the UE can fallback or switch to TN mode after a second time interval has elapsed.

[0237] For reference FIG. 16 As described, a first time interval T can be applied based on the time slot of the received DCI, including the NTI. gap1 .

[0238] FIG. 20 This is a diagram used to explain the method by which a UE receives downlink signals.

[0239] Reference FIG. 20 The UE can perform connections with terrestrial network (TN) cells and non-terrestrial network (NTN) cells on the first frequency band (S201). For example, the UE can detect the SSB for each of the TN and NTN cells, and perform an initial access procedure for the TN cell and an initial access procedure for the NTN cell based on the detected SSB for connection to the TN and NTN cells.

[0240] Then, the UE can receive the first RRC parameter for the TN cell and the second RRC parameter for the NTN cell via RRC signaling (S203). The UE can send and receive signals for the TN cell based on the first RRC parameter, and can send and receive signals / data for the NTN cell based on the second RRC parameter. As described above, the UE can send and receive signals for the TN cell based on the first RRC parameter in TN mode, and can send and receive signals / data for the NTN cell based on the second RRC parameter in NTN mode. The UE can activate only one of the TN mode and NTN mode, and can send and receive signals / data only for one mode. That is, the UE can send and receive signals / data based on TN mode and NTN mode simultaneously.

[0241] Then, the UE can receive downlink control information (DCI) based on the default mode, which is set as the default mode between TN mode and NTN mode (S205). For example, the UE can have TN mode configured as the default mode and NTN mode configured as a non-default mode. As mentioned above, the default mode can be indicated / configured through the initial access procedure or DCI, or it can be determined / configured directly by the UE.

[0242] Then, when the DCI includes an NTI indicating a switch from the default mode to a non-default mode, the UE can switch the default mode to the non-default mode (S207). As described above, the UE can switch the default mode to the non-default mode by applying a specific time interval. For example, when the DCI does not include data scheduling information, the UE can apply a specific time interval based on the time slot in which the DCI is received. Alternatively, when the DCI includes data scheduling information, the UE can apply a specific time interval based on the time slot in which an ACK for the DCI is sent. Alternatively, the specific time interval may include a first time interval applied when switching from TN mode to NTN mode and a second time interval applied when switching from NTN mode to TN mode. Here, the first time interval can be configured to be a different time from the second time interval; for example, the first time interval can be configured to be a longer time than the second time interval.

[0243] Alternatively, the UE can be switched to a non-default mode based on the NTI included in the DCI. In this case, when no DCI including an NTI indicating a switch from the non-default mode to the default mode is received, the UE can perform a fallback to the default mode based on a preset timer, a mode activation time, or an inactivity indicator. For example, the UE can activate a preset timer when the non-default mode is activated, and can switch / fall back to the default mode after a specific time interval when the preset timer expires. Here, the preset timer can be reset / reinitialized based on the reception of the DCI of scheduling data / signals in the activated non-default mode. Alternatively, when a DCI including the mode activation time and the NTI (the DCI received in the default mode) is received, the UE can activate the non-default mode during the mode activation time. In this case, when the mode activation time has elapsed, the UE can fall back from the non-default mode to the default mode. Here, the mode activation time can be updated using the DCI received in the non-default mode. Alternatively, when the DCI received in the non-default mode includes an inactivity indicator, the UE can perform a fallback to the default mode.

[0244] Therefore, the proposed disclosure can dynamically guide the handover between NTN and TN modes based on NTI in frequency bands where NTN and TN cells coexist. The proposed disclosure can effectively and easily instruct the UE to switch to a mode suitable for the type of service provided to the UE, channel environment, etc., via NTI. The proposed disclosure enables the UE to efficiently perform mode switching by defining new time intervals for mode switching and can clearly predict the timing of mode switching. The proposed disclosure can ensure effective rollback to the default mode by explicitly specifying the period of time for activating the UE's non-default mode using a preset timer, mode activation time, or inactivity indicator.

[0245] In some implementations of this disclosure, transmitting a signal / channel to a UE or BS in a transmission beam can be expressed as transmitting the signal / channel to a spatial domain transmission filter. In some implementations of this disclosure, receiving a signal / channel in a receive beam can be expressed as receiving the signal / channel using a spatial domain receive filter. For example, transmission using the same transmit beam can represent transmission using the same spatial domain transmit filter, and reception using the same receive beam can represent reception using the same spatial domain receive filter.

[0246] The wireless communication technologies implemented in the wireless devices XXX and YYY of this disclosure may include LTE, NR, and 6G, as well as narrowband IoT for low-power communication. In this case, for example, NB-IoT technology may be an example of low-power wide-area network (LPWAN) technology and may be implemented using standards such as LTE Cat NB1 and / or LTE Cat NB2, and is not limited to the names mentioned above. Alternatively or additionally, the wireless communication technologies implemented in the wireless devices XXX and YYY of this disclosure may perform communication based on LTE-M technology. In this case, for example, LTE-M technology may be an example of LPWAN technology and may be referred to by various names such as enhanced machine-type communication (eMTC). For example, LTE-M technology may be implemented by at least one of various standards (including, but not limited to, 1) LTE Cat 0, 2) LTE Cat M1, 3) LTE Cat M2, 4) LTE non-bandwidth limited (non-BL), 5) LTE-MTC, 6) LTE machine-type communication, and / or 7) LTE M, and is not limited to the names mentioned above. Additionally or alternatively, the wireless communication technologies implemented in the wireless devices XXX and YYY of this disclosure may include at least one of Low Power Wide Area Network (LPWAN), Bluetooth, and ZigBee, and are not limited to the aforementioned names. For example, ZigBee technology may be used to generate Personal Area Networks (PANs) for small / low power digital communication based on various standards such as IEEE 802.15.4, and may be referred to by various names.

[0247] The embodiments of this disclosure described above are combinations of the elements and features of this disclosure. Unless otherwise stated, elements or features may be considered selective. Each element or feature may be practiced without combination with other elements or features. Furthermore, embodiments of this disclosure may be constructed by combining a portion of the elements and / or features. The order of operations described in the embodiments of this disclosure may be rearranged. Some constructions of any embodiment may be included in another embodiment and may be replaced by corresponding constructions of another embodiment. It will be apparent to those skilled in the art that claims not expressly referenced in the appended claims may be combined to present embodiments of this disclosure, or may be included as new claims by subsequent amendments after the filing of this application.

[0248] In embodiments of this disclosure, the description focuses on the data transmission and reception relationship between the BS and the UE. This transmission and reception relationship is similarly extended to the signal transmission and reception between the UE and a repeater, or between the BS and a repeater. In this disclosure, specific operations described as being performed by the BS can be performed by upper-layer nodes of the BS. That is, it is apparent that in a network consisting of multiple network nodes including the BS, various operations performed for communication with the UE can be performed by the BS or network nodes other than the BS. The term "BS" can be replaced by the terms "fixed station," "node B," "evolved node B (eNode B or eNB)," or "access point." The term "terminal" can be replaced by the terms "UE," "mobile station (MS)," "mobile subscriber station (MSS)," etc.

[0249] The embodiments of this disclosure can be implemented in various ways (e.g., hardware, firmware, software, or a combination thereof). In a hardware configuration, the embodiments of this disclosure can be implemented using one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSDPs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, etc.

[0250] In firmware or software configuration, embodiments of this disclosure can be implemented in the form of modules, processes, functions, etc. Software code can be stored in memory units and executed by a processor. The memory units are located inside or outside the processor and can send data to and receive data from the processor via various known means.

[0251] It will be apparent to those skilled in the art that this disclosure may be embodied in other specific forms without departing from its characteristics. Therefore, the detailed description should not be construed as limiting in any way and should be considered illustrative. The scope of this disclosure should be determined by a reasonable interpretation of the appended claims, and all modifications within the equivalent scope of this disclosure are included within its scope.

[0252] Industrial applicability

[0253] The embodiments of this disclosure described above can be applied to various mobile communication systems.

Claims

1. A method for a user equipment (UE) to receive downlink signals in a wireless communication system, the method comprising the following steps: It connects to terrestrial network TN cells and non-terrestrial network NTN cells in the first frequency band; The downlink control information (DCI) is received based on the default mode configured in either TN or NTN mode. In TN mode, the transmission and reception of signals based on the TN cell are performed, and in NTN mode, the transmission and reception of signals based on the NTN cell are performed. as well as Based on the indication information for switching the indication mode in the DCI, switch to the non-default mode among the NTN mode and the TN mode that is not configured as the default, and receive the signal based on the non-default mode.

2. The method according to claim 1, wherein, The default mode is configured as the TN mode, and the non-default mode is configured as the NTN mode.

3. The method according to claim 1, wherein, The reception of the signal based on the non-default mode is performed after a specific time interval following the transmission of a first time slot including an ACK message for the DCI or the reception of a second time slot for the DCI.

4. The method according to claim 3, wherein, Since the DCI does not include data scheduling information, the reception of the signal based on the non-default mode is performed after the specific time interval from the first time slot.

5. The method according to claim 3, wherein, Based on the DCI including data scheduling information, the reception of the signal based on the non-default mode is performed after the specific time interval from the second time slot.

6. The method according to claim 3, wherein, The specific interval includes a first time interval applied when switching from the TN mode to the NTN mode and a second time interval applied when switching from the NTN mode to the TN mode.

7. The method according to claim 1, wherein, The non-default mode is activated until the preset timer expires, and the UE reverts to the default mode based on the expiration of the preset timer.

8. The method according to claim 7, wherein, The preset timer is reset or initialized based on the reception of DCI including data scheduling information in the non-default mode.

9. The method according to claim 1, wherein, The non-default mode is activated during the mode activation time included in the DCI, and the UE reverts to the default mode when the mode activation time has elapsed.

10. The method according to claim 1, wherein, The UE reverts to the default mode based on the reception of the DCI in the non-default mode, which includes an inactivity indicator or a mode termination indicator.

11. A computer-readable recording medium for recording a program for performing the method according to claim 1.

12. A user equipment (UE) for receiving downlink signals in a wireless communication system, the UE comprising: At least one transceiver; At least one processor; as well as At least one computer memory, operatively connectable to the at least one processor and storing instructions that, when executed, cause the at least one processor to perform operations. The operation includes: connecting to a terrestrial network (TN) cell and a non-terrestrial network (NTN) cell in a first frequency band; receiving downlink control information (DCI) based on a default mode configured as the default mode between TN and NTN modes; performing signal transmission and reception based on the TN cell in TN mode and signal transmission and reception based on the NTN cell in NTN mode; and switching to a non-default mode not configured as the default mode between NTN and TN modes based on indication information indicating mode switching in the DCI, and receiving the signal based on the non-default mode.

13. The UE according to claim 12, wherein, The default mode is configured as the TN mode, and the non-default mode is configured as the NTN mode.

14. The UE according to claim 12, wherein, The reception of the signal based on the non-default mode is performed after a specific time interval following the transmission of a first time slot including an ACK message for the DCI or the reception of a second time slot for the DCI.

15. The UE according to claim 14, wherein, Since the DCI does not include data scheduling information, the reception of the signal based on the non-default mode is performed after the specific time interval from the first time slot.

16. The UE according to claim 14, wherein, Based on the DCI including data scheduling information, the reception of the signal based on the non-default mode is performed after the specific time interval from the second time slot.

17. The UE according to claim 14, wherein, The specific interval includes a first time interval applied when switching from the TN mode to the NTN mode and a second time interval applied when switching from the NTN mode to the TN mode.

18. A processing apparatus for receiving downlink signals in a wireless communication system, the processing apparatus comprising: At least one processor; as well as At least one computer memory, operatively connectable to the at least one processor and storing instructions that, when executed, cause the at least one processor to perform operations. The operation includes: connecting to a terrestrial network (TN) cell and a non-terrestrial network (NTN) cell in a first frequency band; receiving downlink control information (DCI) based on a default mode configured as the default mode between TN and NTN modes; performing signal transmission and reception based on the TN cell in TN mode and signal transmission and reception based on the NTN cell in NTN mode; and switching to a non-default mode not configured as the default mode between NTN and TN modes based on indication information indicating mode switching in the DCI, and receiving the signal based on the non-default mode.

19. A method for transmitting downlink signals from a base station (BS) to a user equipment (UE) connected to a terrestrial network (TN) cell and a non-terrestrial network (NTN) cell in a first frequency band in a wireless communication system, the method comprising the following steps: The UE is instructed to select one of the TN and NTN modes as the default mode. In the TN mode, the UE performs signal transmission and reception based on the TN cell, and in the NTN mode, the UE performs signal transmission and reception based on the NTN cell. as well as Send downlink control information (DCI), the DCI including indication information indicating a switch from the default mode to a non-default mode that is not configured as the default mode, either the NTN mode or the TN mode.

20. A base station (BS) for transmitting downlink signals in a wireless communication system, the BS comprising: At least one transceiver; At least one processor; as well as At least one computer memory, operatively connectable to the at least one processor and storing instructions that, when executed, cause the at least one processor to perform operations. The operation includes: instructing a user equipment (UE) connected to a terrestrial network (TN) cell and a non-terrestrial network (NTN) cell on a first frequency band to select one of the TN and NTN modes as the default mode; in the TN mode, performing signal transmission and reception based on the TN cell; and in the NTN mode, performing signal transmission and reception based on the NTN cell; and transmitting downlink control information (DCI), the DCI including indication information indicating a switch from the default mode to a non-default mode that is not configured as the default mode in either the NTN or TN modes.

Images