Method and device for repeated downlink transmission through non-terrestrial network

Abstract

According to an embodiment of the present disclosure, provided is a method by which a terminal performs communication in a wireless communication system. The method may comprise the steps of: transmitting a random access preamble to a base station communicating with a terminal through a non-terrestrial network (NTN); receiving, from the base station, a random access response related to the random access preamble; transmitting capability information about the terminal to the base station on the basis of the random access response; and receiving repeated physical downlink shared channel (PDSCH) transmission by the base station on the basis of the capability information.

Description

Method and device for repetitive downlink transmission through a non-terrestrial network

[0001] The present disclosure relates to a non-terrestrial network (NTN) in a wireless communication system, and more specifically to a downlink iterative transmission technique through a non-terrestrial network.

[0002] Communication networks (e.g., 5G communication networks, 6G communication networks, etc.) are being developed to provide communication services that are improved over existing communication networks (e.g., LTE (long term evolution), LTE-A (advanced), etc.). 5G communication networks (e.g., NR (new radio) communication networks) can support frequency bands above 6 GHz as well as frequency bands below 6 GHz. That is, 5G communication networks can support the FR1 band and / or FR2 band. 5G communication networks can support a wider variety of communication services and scenarios compared to LTE communication networks. For example, usage scenarios for 5G communication networks may include eMBB (enhanced Mobile BroadBand), URLLC (Ultra Reliable Low Latency Communication), mMTC (massive Machine Type Communication), etc.

[0003] 6G communication networks can support a wider variety of communication services and scenarios compared to 5G communication networks. 6G communication networks can satisfy requirements for ultra-high performance, ultra-bandwidth, ultra-spatial, ultra-precision, ultra-intelligence, and / or ultra-reliability. 6G communication networks can support diverse and wide frequency bands and can be applied to various usage scenarios (e.g., terrestrial communication, non-terrestrial communication, sidelink communication, etc.).

[0004] Communication networks (e.g., 5G communication networks, 6G communication networks, etc.) can provide communication services to terminals located on the ground. There is an increasing demand for communication services not only on the ground but also for non-ground locations such as airplanes, drones, and satellites, and to meet this demand, technologies for non-terrestrial networks (NTNs) are being discussed. NTNs can be implemented based on 5G communication technologies, 6G communication technologies, etc. For example, in an NTN, communication between a satellite and a communication node located on the ground or a communication node located non-ground (e.g., airplanes, drones, etc.) can be performed based on 5G communication technologies, 6G communication technologies, etc. In an NTN, a satellite can perform the function of a base station in a communication network (e.g., 5G communication networks, 6G communication networks, etc.).

[0005] Meanwhile, the technology forming the background of the invention is written to enhance understanding of the background of the invention and may include content that is not prior art already known to those skilled in the art to which this technology belongs.

[0006] The present disclosure may provide a method and apparatus for effectively performing downlink iterative transmission for a non-terrestrial network in a wireless communication system.

[0007] The present disclosure may provide a method and apparatus for performing signaling for repeated transmission of a physical downlink shared channel (PDSCH) for a non-terrestrial network in a wireless communication system.

[0008] The present disclosure may provide a method and apparatus for performing signaling for the repeated transmission of a PDCCH (physical downlink control channel) CSS (common search space) for a non-terrestrial network in a wireless communication system.

[0009] The technical objectives to be achieved in this disclosure are not limited to those mentioned above, and other unmentioned technical problems may be considered by those skilled in the art to which the technical configuration of this disclosure applies, based on the embodiments of this disclosure described below.

[0010] According to one embodiment of the present disclosure, a method is provided for a terminal to perform communication in a wireless communication system. The method may include the steps of: transmitting a random access preamble to a base station communicating with the terminal via a Non-Terrestrial Network (NTN); receiving a random access response associated with the random access preamble from the base station; transmitting capability information of the terminal to the base station based on the random access response; and receiving a Physical Downlink Shared Channel (PDSCH) repeated transmission by the base station based on the capability information.

[0011] According to one embodiment of the present disclosure, a terminal is provided for performing communication in a wireless communication system. The terminal may include at least one transceiver, at least one processor, and at least one memory connected to the at least one processor to be operable and storing instructions that control the terminal to perform operations when executed by the processor. The operations may include the steps of transmitting a random access preamble to a base station communicating with the terminal via an NTN, receiving a random access response associated with the random access preamble from the base station, transmitting capability information of the terminal to the base station based on the random access response, and receiving a PDSCH iteration transmission by the base station based on the capability information.

[0012] According to one embodiment of the present disclosure, a method is provided for a base station to perform communication in a wireless communication system. The method may include the steps of receiving a random access preamble from a terminal communicating with the base station via an NTN, transmitting a random access response associated with the random access preamble, receiving capability information of the terminal from the terminal based on the transmission of the random access response, and transmitting a PDSCH iterative transmission to the terminal based on the capability information.

[0013] According to one embodiment of the present disclosure, a base station is provided for performing communication in a wireless communication system. The base station may include at least one transceiver, at least one processor, and at least one memory connected to the at least one processor to be operable and storing instructions that control the base station to perform operations when executed by the processor. The operations may include receiving a random access preamble from a terminal communicating with the base station via an NTN, transmitting a random access response associated with the random access preamble, receiving capability information of the terminal from the terminal based on the transmission of the random access response, and transmitting a PDSCH iteration transmission to the terminal based on the capability information.

[0014] According to one embodiment of the present disclosure, NTN downlink coverage can be expanded.

[0015] According to one embodiment of the present disclosure, signaling for repeated transmission of Msg4 can be performed efficiently.

[0016] According to one embodiment of the present disclosure, signaling for repeated PDCCH transmission through the Common Search Space (CSS) can be efficiently performed.

[0017] The effects obtainable from the embodiments of the present disclosure are not limited to those mentioned above, and other unmentioned effects can be clearly derived and understood by those skilled in the art to which the technical configuration of the present disclosure applies from the description of the embodiments of the present disclosure below. That is, unintended effects resulting from implementing the configuration described in the present disclosure can also be derived by those skilled in the art from the embodiments of the present disclosure.

[0018] FIGS. 1A and FIGS. 1B are conceptual diagrams illustrating some embodiments of a non-ground network.

[0019] FIGS. 2A to 2C are conceptual diagrams illustrating some embodiments of a non-ground network.

[0020] FIG. 3 is a block diagram illustrating a first embodiment of a communication node constituting a non-terrestrial network.

[0021] FIG. 4 is a block diagram illustrating a first embodiment of communication nodes performing communication.

[0022] FIG. 5A is a block diagram illustrating a first embodiment of a transmission path, and FIG. 5B is a block diagram illustrating a first embodiment of a reception path.

[0023] FIG. 6 is a conceptual diagram illustrating an example of a system frame in a communication system.

[0024] FIG. 7 is a conceptual diagram illustrating an example of a subframe in a communication system.

[0025] FIG. 8 is a conceptual diagram illustrating an example of a slot in a communication system.

[0026] Figure 9 is a diagram showing the timing relationship between the uplink and downlink in a communication system.

[0027] FIG. 10A is a conceptual diagram illustrating a first embodiment of a protocol stack of the user plane in a transparent payload-based non-terrestrial network, and FIG. 10B is a conceptual diagram illustrating a first embodiment of a protocol stack of the control plane in a transparent payload-based non-terrestrial network.

[0028] FIG. 11A is a conceptual diagram illustrating a first embodiment of a protocol stack of the user plane in a regenerative payload-based non-terrestrial network, and FIG. 11B is a conceptual diagram illustrating a first embodiment of a protocol stack of the control plane in a regenerative payload-based non-terrestrial network.

[0029] FIG. 12 is a diagram illustrating an example of an NTN that provides non-terrestrial NR access to a UE through an NTN payload and an NTN gateway.

[0030] Figure 13 is a diagram illustrating the timing relationship between objects included in NTN.

[0031] Figure 14 is a diagram illustrating the uplink and downlink transmitted between the gNB and the UE during the initial cell connection.

[0032] FIG. 15 is a diagram illustrating an example of a terminal reporting to a base station by identifying a range that includes RSRP measurements.

[0033] FIG. 16 is a flowchart illustrating a method in which a terminal performs communication according to one embodiment of the present disclosure.

[0034] FIG. 17 is a flowchart illustrating a method in which a base station performs communication according to one embodiment of the present disclosure.

[0035] According to one embodiment of the present disclosure, a method is provided for a terminal to perform communication in a wireless communication system. The method may include the steps of: transmitting a random access preamble to a base station communicating with the terminal via a Non-Terrestrial Network (NTN); receiving a random access response associated with the random access preamble from the base station; transmitting capability information of the terminal to the base station based on the random access response; and receiving a Physical Downlink Shared Channel (PDSCH) repeated transmission by the base station based on the capability information.

[0036] The present disclosure is capable of various modifications and may have various embodiments, and specific embodiments are illustrated in the drawings and described in detail. However, this is not intended to limit the present disclosure to specific embodiments, and it should be understood that it includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the present disclosure.

[0037] Terms such as "first," "second," etc., may be used to describe various components, but said components should not be limited by said terms. Such terms are used solely for the purpose of distinguishing one component from another. For example, without departing from the scope of the present disclosure, the first component may be named the second component, and similarly, the second component may be named the first component. The term "and / or" includes a combination of a plurality of related described items or any of a plurality of related described items.

[0038] In the present disclosure, "at least one of A and B" may mean "at least one of A or B" or "at least one of one or more combinations of A and B". Additionally, in the present disclosure, "at least one of A and B" may mean "at least one of A or B" or "at least one of one or more combinations of A and B".

[0039] In the present disclosure, (re)transmission may mean "transmission," "retransmission," or "transmission and retransmission"; (re)setting may mean "setting," "resetting," or "setting and resetting"; (re)connection may mean "connection," "reconnection," or "connection and reconnection"; and (re)connection may mean "connection," "reconnection," or "connection and reconnection".

[0040] When it is stated that a component is "connected" or "connected" to another component, it should be understood that while it may be directly connected or connected to that other component, there may also be other components in between. On the other hand, when it is stated that a component is "directly connected" or "directly connected" to another component, it should be understood that there are no other components in between.

[0041] The terms used in this disclosure are used merely to describe specific embodiments and are not intended to limit this disclosure. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this disclosure, terms such as “comprising” or “having” are intended to specify the presence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0042] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which this disclosure pertains. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this disclosure.

[0043] Hereinafter, preferred embodiments of the present disclosure will be described in more detail with reference to the attached drawings. To facilitate an overall understanding of the present disclosure, the same reference numerals are used for identical components in the drawings, and redundant descriptions of identical components are omitted. Operations according to combinations of embodiments, extensions of embodiments, and / or modifications of embodiments may be performed, in addition to the embodiments explicitly described in the present disclosure. The performance of some operations may be omitted, and the order of operations may be changed.

[0044] In the embodiments, even when a method performed at a first communication node among the communication nodes (e.g., transmission or reception of a signal) is described, the corresponding second communication node may perform a method corresponding to the method performed at the first communication node (e.g., reception or transmission of a signal). That is, when the operation of a UE (user equipment) is described, the corresponding base station may perform an operation corresponding to the operation of the UE. Conversely, when the operation of a base station is described, the corresponding UE may perform an operation corresponding to the operation of the base station. In a non-terrestrial network (NTN) (e.g., a payload-based NTN), the operation of the base station may refer to the operation of a satellite, and the operation of the satellite may refer to the operation of the base station.

[0045] A base station may be referred to as Node B, evolved Node B, gNode B (next generation node B), gNB, device, apparatus, node, communication node, BTS (base transceiver station), RRH (radio remote head), TRP (transmission reception point), RU (radio unit), RSU (road side unit), radio transceiver, access point, access node, etc. A UE may be referred to as terminal, device, apparatus, node, communication node, end node, access terminal, mobile terminal, station, subscriber station, mobile station, portable subscriber station, OBU (on-broad unit), etc.

[0046] In the present disclosure, signaling may be at least one of upper-layer signaling, MAC signaling, or PHY (physical) signaling. A message used for upper-layer signaling may be referred to as an "upper-layer message" or an "upper-layer signaling message." A message used for MAC signaling may be referred to as a "MAC message" or a "MAC signaling message." A message used for PHY signaling may be referred to as a "PHY message" or a "PHY signaling message." Upper-layer signaling may refer to the transmission and reception operations of system information (e.g., MIB (master information block), SIB (system information block)) and / or RRC messages. MAC signaling may refer to the transmission and reception operations of MAC CE (control element). PHY signaling may refer to the transmission and reception operations of control information (e.g., DCI (downlink control information), UCI (uplink control information), SCI (sidelink control information)).

[0047] In the present disclosure, "setting an operation (e.g., transmission operation)" may mean that "setting information for said operation (e.g., information element, parameter)" and / or "information directing the performance of said operation" is signaled. "Setting an information element (e.g., parameter)" may mean that said information element is signaled. In the present disclosure, "signal and / or channel" may mean signal, channel, or "signal and channel," and signal may be used to mean "signal and / or channel."

[0048] A communication system may include at least one of a terrestrial network, an NTN, a 4G communication network (e.g., an LTE (long-term evolution) communication network), a 5G communication network (e.g., an NR (new radio) communication network), or a 6G communication network. Each of the 4G communication network, the 5G communication network, and the 6G communication network may include a terrestrial network and / or an NTN. The NTN may be operated based on at least one of LTE communication technology, 5G communication technology, or 6G communication technology. The NTN may provide communication services in various frequency bands.

[0049] The communication networks to which the embodiments of the present disclosure are applied are not limited to those described below, and the embodiments may be applied to various communication networks (e.g., 4G communication networks, 5G communication networks, and / or 6G communication networks). Here, the term "communication network" may be used interchangeably with "communication system."

[0050] FIGS. 1A and 1B are conceptual diagrams illustrating some embodiments of a non-terrestrial network. FIGS. 1A and 1B illustrate the structure of a transparent-based NTN according to an embodiment of the present disclosure.

[0051] Referring to FIG. 1A, the NTN may include a satellite (110), a communication node (120), a gateway (130), a data network (140), etc. A unit including the satellite (110) and the gateway (130) may be referred to as a remote radio unit (RRU). The satellite (110) may be a low earth orbit (LEO) satellite, a medium earth orbit (MEO) satellite, a geostationary earth orbit (GEO) satellite, a high elliptical orbit (HEO) satellite, or an unmanned aircraft system (UAS) platform. A UAS platform may include a high altitude platform station (HAPS). A non-GEO satellite may be a LEO satellite and / or an MEO satellite.

[0052] The communication node (120) may include a device located on the ground (e.g., UE, terminal) and a device located off the ground (e.g., airplane, drone). A service link may be established between the satellite (110) and the communication node (120), and the service link may be a radio link. The satellite (110) may be referred to as an NTN payload. The gateway (130) may support multiple NTN payloads. The satellite (110) may provide communication services to the communication node (120) using one or more beams. The shape of the beam footprint of the satellite (110) may be elliptical or circular.

[0053] In NTN, three types of service links can be supported as follows.

[0054] - Earth-fixed: Service links can be provided by beam(s) that always continuously cover the same geographic area (e.g., GSO (Geosynchronous Orbit) satellites)

[0055] - Quasi-earth-fixed: Service links may be provided by beam(s) that cover one geographic area for a limited period and another geographic area for a different period (e.g., NGSO (non-GSO) satellites generating steerable beams).

[0056] - Earth-moving: Service links may be provided by beam(s) moving across the Earth's surface (e.g., NGSO satellites generating fixed beams or non-steeringable beams)

[0057] A communication node (120) can communicate with a satellite (110) (e.g., downlink communication, uplink communication) using 4G communication technology, 5G communication technology, and / or 6G communication technology. Communication between the satellite (110) and the communication node (120) can be performed using an NR-Uu interface and / or a 6G-Uu interface. If dual connectivity (DC) is supported, the communication node (120) can be connected to another base station (e.g., a base station supporting 4G functions, 5G functions, and / or 6G functions) as well as the satellite (110), and can perform DC operations based on the technology defined in the 4G standard, 5G standard, and / or 6G standard.

[0058] The gateway (130) may be located on the ground, and a feeder link may be established between the satellite (110) and the gateway (130). The feeder link may be a wireless link. The gateway (130) may be referred to as an 'NTN gateway'. Communication between the satellite (110) and the gateway (130) may be performed based on an NR-Uu interface, a 6G-Uu interface, or a satellite radio interface (SRI). The gateway (130) may be connected to a data network (140). A "core network" may exist between the gateway (130) and the data network (140). In this case, the gateway (130) may be connected to the core network, and the core network may be connected to the data network (140). The core network may support 4G communication technology, 5G communication technology, and / or 6G communication technology. For example, the core network may include an access and mobility management function (AMF), a user plane function (UPF), a session management function (SMF), etc. Communication between the gateway (130) and the core network may be performed based on an NG-C / U interface or a 6G-C / U interface.

[0059] As shown in FIG. 1B, in a transparent payload-based NTN, a base station and a core network may exist between the gateway (130) and the data network (140).

[0060] Referring to FIG. 1B, the gateway can be connected to a base station, the base station can be connected to a core network, and the core network can be connected to a data network. Each of the base station and the core network can support 4G communication technology, 5G communication technology, and / or 6G communication technology. Communication between the gateway and the base station can be performed based on an NR-Uu interface or a 6G-Uu interface, and communication between the base station and the core network (e.g., AMF, UPF, SMF) can be performed based on an NG-C / U interface or a 6G-C / U interface.

[0061] FIGS. 2A to 2C are conceptual diagrams illustrating some embodiments of a non-terrestrial network. FIGS. 2A to 2C illustrate the structure of a regenerative-based NTN according to an embodiment of the present disclosure.

[0062] Referring to FIG. 2A, the NTN may include a first satellite (211), a second satellite (212), a communication node (220), a gateway (230), a data network (1240), etc. Each of the first satellite (211) and the second satellite (212) may perform a regeneration operation (e.g., demodulation operation, decoding operation, re-encoding operation, re-modulation operation, and / or filtering operation) on a payload received from other entities constituting the NTN (e.g., communication node (220), gateway (230)), and may transmit the regenerated payload.

[0063] Each of the first satellite (211) and the second satellite (212) may be an LEO satellite, MEO satellite, GEO satellite, HEO satellite, or UAS platform. The UAS platform may include a HAPS. Satellite #1 (211) may be connected to the second satellite (212), and an inter-satellite link (ISL) may be established between the first satellite (211) and the second satellite (212). The ISL may operate in a radio frequency (RF) frequency or optical band. The ISL may be established optionally. The communication node (220) may include a communication node located on the ground (e.g., UE, terminal) and a communication node located off the ground (e.g., airplane, drone). A service link (e.g., wireless link) may be established between Satellite #1 (211) and the communication node (220). The first satellite (211) may be referred to as an NTN payload. The first satellite (211) can provide communication services to the communication node (220) using one or more beams.

[0064] The communication node (220) can communicate (e.g., downlink communication, uplink communication) with the first satellite (211) using 4G communication technology, 5G communication technology, and / or 6G communication technology. Communication between the first satellite (211) and the communication node (220) can be performed using an NR-Uu interface or a 6G-Uu interface. If DC is supported, the communication node (220) can be connected to the first satellite (211) as well as other base stations (e.g., base stations supporting 4G functions, 5G functions, and / or 6G functions), and can perform DC operations based on the technology defined in the 4G standard, 5G standard, and / or 6G standard.

[0065] The gateway (230) may be located on the ground, and a feeder link may be established between the first satellite (211) and the gateway (230), and a feeder link may be established between the second satellite (212) and the gateway (230). The feeder link may be a wireless link. If an ISL is not established between the first satellite (211) and the second satellite (212), a feeder link between the first satellite (211) and the gateway (230) may be established mandatorily. Communication between the gateway (230) and each of the first satellite (211) and satellite #2 (212) may be performed based on an NR-Uu interface, a 6G-Uu interface, or SRI. The gateway (230) may be connected to a data network (240).

[0066] As in the embodiments of FIGS. 2B and FIG. 2C, a core network may exist between the gateway (230) and the data network (240).

[0067] Referring to FIGS. 2B and 2C, the gateway can be connected to a core network, and the core network can be connected to a data network. The core network can support 4G communication technology, 5G communication technology, and / or 6G communication technology. For example, the core network may include an AMF, UPF, SMF, etc. Communication between the gateway and the core network may be performed based on an NG-C / U interface or a 6G-C / U interface. The functions of a base station may be performed by a satellite. That is, the base station may be located on a satellite. The payload may be processed by the base station located on the satellite. Base stations located on different satellites may be connected to the same core network. A single satellite may have one or more base stations. In the NTN of FIG. 2B, an ISL between satellites may not be established, while in the NTN of FIG. 2C, an ISL between satellites may be established.

[0068] Meanwhile, entities constituting the NTN illustrated in FIG. 1A, FIG. 1B, FIG. 2A, FIG. 2B, and / or FIG. 2C (e.g., satellite, base station, UE, communication node, gateway, etc.) may be configured as follows. In the present disclosure, an entity may be referred to as a communication node.

[0069] FIG. 3 is a block diagram illustrating a first embodiment of a communication node constituting a non-terrestrial network. The structure exemplified in FIG. 3 can be understood as the structure of at least part of a communication node, base station, satellite, or core network entity. The wireless device (300) exemplified in FIG. 3 may be a mobile terminal such as a smartphone, tablet PC, or wearable device, but is not limited thereto.

[0070] Referring to FIG. 3, the wireless device (300) may include at least one control unit (310), at least one memory (320), at least one power supply unit (330), at least one transceiver unit (340), at least one input unit (350), at least one output unit (360) and / or at least one antenna (370).

[0071] The control unit (310) can control the memory (320) and / or the transmission / reception unit (340) and may be configured to implement the descriptions, functions, procedures, proposals, methods, and / or operation sequences disclosed in this disclosure. The memory (320) may be connected to the control unit (310) and may store various information related to the operation of the control unit (310). For example, the memory (320) may store software code including instructions for performing some or all of the controls controlled by the control unit (310) or for performing the descriptions, functions, procedures, proposals, methods, and / or operation sequences disclosed in this disclosure. The configuration of the memory is not limited in a particular way. For example, it may be configured as at least one of read-only memory (ROM) and random access memory (RAM).

[0072] At least one control unit (310) may be referred to as a processor, microcontroller, microprocessor, or microcomputer. The descriptions, functions, procedures, proposals, methods, and / or flowcharts of operations disclosed in this disclosure may be implemented using firmware or software in the form of code, instructions, and / or sets of instructions. Here, the firmware or software may execute other programs stored in memory (320), such as an OS. The control unit (310) may be implemented to support differently weighted beamforming or directional routing operations to effectively control the outgoing signal from at least one antenna (370) to a desired direction.

[0073] Additionally, at least one control unit (310) may be coupled with a backhaul or network interface. The wireless device (300) may communicate with other wireless devices through the backhaul or network interface. The control unit (310) may include at least one processor. The processor may mean a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor on which the methods according to embodiments of the present disclosure are performed.

[0074] At least one transceiver (340) may be connected to a control unit (310) and may transmit and / or receive a wireless signal through at least one antenna (370). The transceiver (340) may include a transmitter and / or receiver. At least one transceiver (340) may transmit user data, control information, wireless signals / channels, etc., as described in the methods and / or operation flowcharts of the present disclosure to at least one other device. For example, at least one transceiver (340) may be connected to at least one control unit (310) and may transmit and receive wireless signals. Additionally, at least one control unit (310) may control at least one transceiver (340) to transmit user data, control information, or wireless signals to at least one other device. At least one transmitter (340) may receive a signal transmitted by another wireless device from at least one antenna (370). Additionally, at least one transceiver (340) can down-convert or up-convert the received signal to generate a baseband signal. At least one antenna (370) may be a plurality of physical antennas or a plurality of logical antennas (e.g., antenna ports).

[0075] The input unit (350) can acquire information such as user input, video, and audio, and may include various input means such as various mechanical / electronic input means, cameras, and microphones. The output unit (360) is intended to provide information to a user by generating output related to sight, hearing, or touch, and may include a display, speaker, vibration module, etc. The wireless device (300) supplies power through the power unit (330), and the power unit (330) may include a wired / wireless charging circuit, battery, etc.

[0076] A more detailed example of the structure of the control unit (310) and / or the transceiver unit (340) is shown in FIG. 4. FIG. 4 is a block diagram illustrating a first embodiment of communication nodes performing communication. FIG. 4 illustrates the structure of a first communication node (400a) and a second communication node (400b) that transmit and / or receive signals. In FIG. 4, each of the first communication node (400a) and the second communication node (400b) may be a base station or a UE.

[0077] Referring to FIG. 4, the first communication node (400a) can transmit a signal to the second communication node (400b). The transmission processor (411) included in the first communication node (400a) can receive data (e.g., data unit) from the data source (410). The transmission processor (411) can receive control information from the controller (416). The control information may include at least one of system information, RRC setting information (e.g., information set by RRC signaling), MAC control information (e.g., MAC CE), or PHY control information (e.g., DCI, SCI).

[0078] The transmitting processor (411) can generate data symbol(s) by performing processing operations on data (e.g., encoding operation, symbol mapping operation, etc.). The transmitting processor (411) can generate control symbol(s) by performing processing operations on control information (e.g., encoding operation, symbol mapping operation, etc.). Additionally, the transmitting processor (411) can generate synchronization / reference symbol(s) for synchronization signals and / or reference signals.

[0079] The Tx MIMO processor (412) can perform spatial processing operations (e.g., precoding operations) on data symbol(s), control symbol(s), and / or synchronization / reference symbol(s). The output (e.g., symbol stream) of the Tx MIMO processor (412) can be provided to modulators (MODs) included in transceivers (413a to 413t). The modulators (MODs) can perform processing operations on the symbol stream to generate modulated symbols and perform additional processing operations on the modulated symbols (e.g., analog conversion operations, amplification operations, filtering operations, up-conversion operations) to generate signals. The signals generated by the modulators (MODs) of the transceivers (413a to 413t) can be transmitted through antennas (414a to 414t).

[0080] Signals transmitted by the first communication node (400a) can be received at the antennas (464a to 464r) of the second communication node (400b). Signals received at the antennas (464a to 464r) can be provided to demodulators (DEMODs) included in the transceivers (463a to 463r). The demodulators (DEMODs) can obtain samples by performing processing operations on the signals (e.g., filtering operation, amplification operation, down-conversion operation, digital conversion operation). The demodulators (DEMODs) can obtain symbols by performing additional processing operations on the samples. The MIMO detector (462) can perform MIMO detection operations on the symbols. The receiving processor (461) can perform processing operations on the symbols (e.g., deinterleaving operation, decoding operation). The output of the receiving processor (461) can be provided to the data sink (460) and the controller (466). For example, data can be provided to the data sink (460), and control information can be provided to the controller (466).

[0081] Meanwhile, the second communication node (400b) can transmit a signal to the first communication node (400a). The transmission processor (468) included in the second communication node (400b) can receive data (e.g., data unit) from the data source (467) and can generate data symbol(s) by performing a processing operation on the data. The transmission processor (468) can receive control information from the controller (466) and can generate control symbol(s) by performing a processing operation on the control information. Additionally, the transmission processor (468) can generate reference symbol(s) by performing a processing operation on a reference signal.

[0082] The Tx MIMO processor (469) can perform spatial processing operations (e.g., precoding operations) on data symbol(s), control symbol(s), and / or reference symbol(s). The output (e.g., symbol stream) of the Tx MIMO processor (469) can be provided to modulators (MODs) included in transceivers (463a to 463t). The modulators (MODs) can perform processing operations on the symbol stream to generate modulated symbols and perform additional processing operations (e.g., analog conversion operations, amplification operations, filtering operations, up-conversion operations) on the modulated symbols to generate signals. The signals generated by the modulators (MODs) of the transceivers (463a to 463t) can be transmitted through antennas (464a to 464t).

[0083] Signals transmitted by the second communication node (400b) can be received at the antennas (414a to 414r) of the first communication node (400a). Signals received at the antennas (414a to 414r) can be provided to demodulators (DEMODs) included in the transceivers (413a to 413r). The demodulators (DEMODs) can obtain samples by performing processing operations on the signals (e.g., filtering operation, amplification operation, down-conversion operation, digital conversion operation). The demodulators (DEMODs) can obtain symbols by performing additional processing operations on the samples. The MIMO detector (420) can perform MIMO detection operations on the symbols. The receiving processor (419) can perform processing operations on the symbols (e.g., deinterleaving operation, decoding operation). The output of the receiving processor (419) can be provided to the data sink (418) and the controller (416). For example, data can be provided to the data sink (418), and control information can be provided to the controller (416).

[0084] The memories (415 and 465) may store data, control information, and / or program code. The scheduler (417) may perform scheduling operations for communication. The processors (411, 412, 419, 461, 468, 469) and controllers (416, 466) shown in FIG. 4 may be the processor (310) shown in FIG. 3 and may be used to perform the methods described in this disclosure.

[0085] FIG. 5A is a block diagram illustrating a first embodiment of a transmission path, and FIG. 5B is a block diagram illustrating a first embodiment of a reception path.

[0086] Referring to FIGS. 5A and 5B, the transmission path (510) may be implemented at a communication node that transmits the signal, and the reception path (520) may be implemented at a communication node that receives the signal. The transmission path (510) may include a channel coding and modulation block (511), an S-to-P (serial-to-parallel) block (512), an N IFFT (Inverse Fast Fourier Transform) block (513), a P-to-S (parallel-to-serial) block (514), a CP (cyclic prefix) addition block (515), and an UC (up-converter) (UC) (516). The receiving path (520) may include a DC (down-converter) (521), a CP removal block (522), an S-to-P block (523), an N FFT block (524), a P-to-S block (525), and a channel decoding and demodulation block (526). Here, N may be a natural number.

[0087] Information bits in the transmission path (510) can be input to the channel coding and modulation block (511). The channel coding and modulation block (511) can perform coding operations (e.g., LDPC (low-density parity check) coding operations, polar coding operations, etc.) and modulation operations (e.g., QPSK (Quadrature Phase Shift Keying), QAM (Quadrature Amplitude Modulation), etc.) on the information bits. The output of the channel coding and modulation block (511) may be a sequence of modulation symbols.

[0088] The S-to-P block (512) can convert modulation symbols in the frequency domain into parallel symbol streams to generate N parallel symbol streams. N can be the IFFT size or the FFT size. The N IFFT block (513) can generate signals in the time domain by performing IFFT operations on the N parallel symbol streams. The P-to-S block (514) can convert the output of the N IFFT block (513) (e.g., parallel signals) into a serial signal to generate a serial signal.

[0089] The CP addition block (515) can insert CP into the signal. The UC (516) can up-convert the frequency of the output of the CP addition block (515) to an RF (radio frequency) frequency. Additionally, the output of the CP addition block (515) can be filtered in the baseband before up-conversion.

[0090] A signal transmitted from the transmission path (510) can be input into the reception path (520). The operation in the reception path (520) may be the inverse operation of the operation in the transmission path (510). The DC (521) may down-convert the frequency of the received signal to a baseband frequency. The CP removal block (522) may remove CP from the signal. The output of the CP removal block (522) may be a serial signal. The S-to-P block (523) may convert the serial signal into parallel signals. The NFFT block (524) may generate N parallel signals by performing an FFT algorithm. The P-to-S block (525) may convert the parallel signals into a sequence of modulation symbols. The channel decoding and demodulation block (526) may perform a demodulation operation on the modulation symbols and restore data by performing a decoding operation on the result of the demodulation operation.

[0091] In FIGS. 5A and 5B, Discrete Fourier Transform (DFT) and Inverse DFT (IDFT) may be used instead of FFT and IFFT. In FIGS. 5A and 5B, each of the blocks (e.g., components) may be implemented by at least one of hardware, software, or firmware. For example, in FIGS. 5A and 5B, some blocks may be implemented by software, and the remaining blocks may be implemented by hardware or a "combination of hardware and software." In FIGS. 5A and 5B, one block may be subdivided into multiple blocks, multiple blocks may be integrated into one block, some blocks may be omitted, and blocks supporting other functions may be added.

[0092] FIG. 6 is a conceptual diagram illustrating an example of a system frame in a communication system.

[0093] Referring to Fig. 6, time resources in a communication system can be divided into frames. For example, system frames can be set consecutively in the time domain of the communication system. The length of a system frame can be 10 ms (millisecond). The system frame number (SFN) can be set from #0 to #1023. In this case, 1024 system frames can be repeated in the time domain of the communication system. For example, the SFN of a system frame after system frame #1023 can be #0.

[0094] A single system frame may contain two half frames. The length of a single half frame may be 5ms. A half frame located at the beginning of the system frame may be referred to as "Half Frame #0", and a half frame located at the end of the system frame may be referred to as "Half Frame #1". A system frame may contain 10 subframes. The length of a single subframe may be 1ms. Within a single system frame, the 10 subframes may be referred to as "Subframe #0-9".

[0095] FIG. 7 is a conceptual diagram illustrating an example of a subframe in a communication system.

[0096] Referring to FIG. 7, one subframe may contain n slots, where n is a natural number. Thus, one subframe may consist of one or more slots.

[0097] FIG. 8 is a conceptual diagram illustrating an example of a slot in a communication system.

[0098] Referring to FIG. 8, a slot may contain one or more symbols. A slot illustrated in FIG. 8 may contain 14 symbols. The length of the slot may vary depending on the number of symbols included in the slot and the length of the symbols. Alternatively, the length of the slot may vary depending on the numerology.

[0099] Numerals applied to physical signals and channels in a communication system may be variable. Numerals may be variable to meet various technical requirements of the communication system. In a communication system where CP (cyclic prefix) based OFDM waveform technology is applied, numerals may include subcarrier spacing and CP length (or CP type). [Table 1] may be an example of a method for configuring numerals for a CP-OFDM based communication system. Depending on the frequency band in which the communication system operates, at least some of the numerals in [Table 1] may be supported. Additionally, numerals not listed in [Table 1] may be further supported in the communication system.

[0100] Subcarrier Spacing 15kHz 30kHz 60kHz 120kHz 240kHz 480kHz OFDM Symbol Length [μs] 66.733.316.78.34.22.1 CP Length [μs] 4.762.381.190.600.300.151 Number of OFDM Symbols in ms 142856112224448

[0101] When the subcarrier spacing is 15 kHz (e.g., μ=0), the slot length may be 1 ms. In this case, one system frame may contain 10 slots. When the subcarrier spacing is 30 kHz (e.g., μ=1), the slot length may be 0.5 ms. In this case, one system frame may contain 20 slots.

[0102] When the subcarrier spacing is 60 kHz (e.g., μ=2), the slot length may be 0.25 ms. In this case, one system frame may contain 40 slots. When the subcarrier spacing is 120 kHz (e.g., μ=3), the slot length may be 0.125 ms. In this case, one system frame may contain 80 slots. When the subcarrier spacing is 240 kHz (e.g., μ=4), the slot length may be 0.0625 ms. In this case, one system frame may contain 160 slots.

[0103] A symbol can be set as a downlink (DL) symbol, a flexible (FL) symbol, or an uplink (UL) symbol. A slot consisting only of a DL symbol can be referred to as a "DL slot," a slot consisting only of an FL symbol can be referred to as a "FL slot," and a slot consisting only of a UL symbol can be referred to as a "UL slot."

[0104] Figure 9 is a diagram showing the timing relationship between the uplink and downlink in a communication system.

[0105] There is one frame set in the uplink, and there is also one frame set in the downlink of each carrier. The uplink frame number I for transmission from the UE is T TA =(N TA +N TA,offset +N common TA,adj +N UE TA,adj )T C It must start previously, and this must coincide with the start of the corresponding downlink frame observed in the UE.

[0106] Here, N TA and N TA,offset This can be provided by adjusting the transmission timing of the synchronization procedure. However, for msgA transmission in PUSCH (physical uplink shared channel), NTA = 0.

[0107] N common TA,adj is derived from the upper layer parameters ta-Common, ta-CommonDrift, and ta-CommonDriftVariant, which is N if not configured. common TA,adj = 0.

[0108] N UE TA,adj is calculated by the UE only when the UE's position and related upper-layer parameters are configured according to the transmission timing adjustment of the synchronization procedure, and otherwise N UE TA,adj = 0.

[0109] As described above, the timing of the downlink and uplink can be adjusted based on the transmission timing adjustment of the synchronization procedure.

[0110] The aforementioned TA (timing advance) can be determined based on the signal transmission and reception times of a random access procedure. For example, a base station can determine the TA based on the arrival time of a preamble transmitted by a terminal.

[0111] A terminal that has performed a random access procedure can receive configuration information from a base station and transmit a PUSCH based on the configuration information. Specifically, the terminal can identify uplink resources and / or determine uplink transmission power based on control information and / or configuration information received from the base station. Then, the terminal can transmit a PUSCH using the determined power through the identified resources.

[0112] PUSCH transmission can be controlled via a physical uplink control channel (PUCCH). In NR, the terminal transmits uplink control information (UCI) to the base station via the PUCCH. The control information may include at least one of a HARQ-ACK indicating whether demodulation / decoding of a transport block (TB) received by the terminal via PDSCH was successful, a scheduling request (SR) in which the terminal requests resource allocation from the PUSCH base station for uplink data transmission, and channel state information (CSI) which is information for reporting the channel status of the terminal.

[0113] PUCCH can be transmitted repeatedly. Under given conditions, the terminal may perform repeated transmission of PUCCH based on configuration information from the base station. For example, if the terminal does not have a dedicated PUCCH resource configuration and has the ability to repeatedly transmit PUCCH containing HARQ-ACK information, the terminal may determine the number of slots for repeating PUCCH transmission containing HARQ-ACK information based on the upper layer configuration (e.g., numberOfPUCCHforMsg4HARQACK-RepetitionsList) and / or control information (e.g., the DAI (downlink assignment index) field of the DCI), and perform repeated PUCCH transmission in the determined number of slots. In this case, the terminal may apply frequency hopping.

[0114] Meanwhile, NTN reference scenarios can be defined as shown in [Table 2] below.

[0115] NTN illustrated in Fig. 1A, NTNGEO illustrated in Fig. 2A, Scenario A, BLEO (Adjustable Beam) Scenario C1, Scenario D1, LEO (Beam Moving with Satellite) Scenario C2, Scenario D2

[0116] In the NTN depicted in FIG. 1A and / or FIG. 1B, if the satellite (110) is a GEO satellite (e.g., a GEO satellite supporting transparent functions), this may be referred to as “Scenario A”. In the NTN depicted in FIG. 2A, FIG. 2B, and / or FIG. 2C, if the first satellite (211) and the second satellite (212) are each GEO satellites (e.g., GEO supporting regeneration functions), this may be referred to as “Scenario B”.

[0117] In the NTN depicted in FIG. 1A and / or FIG. 1B, if the satellite (110) is a LEO satellite having steerable beams, this may be referred to as "Scenario C1". In the NTN depicted in FIG. 1A and / or FIG. 1B, if the satellite (110) is a LEO satellite having beams that move with the satellite, this may be referred to as "Scenario C2". In the NTN depicted in FIG. 2A, FIG. 2B, and / or FIG. 2C, if the first satellite (211) and the second satellite (212) are each LEO satellites having steerable beams, this may be referred to as "Scenario D1". In the NTN depicted in FIG. 2A, FIG. 2B, and / or FIG. 2C, if the first satellite (211) and satellite #2 (212) are each LEO satellites having beams that move with the satellite, this may be referred to as "Scenario D2".

[0118] The parameters for the NTN reference scenarios defined in [Table 2] can be defined as shown in [Table 3] below.

[0119] Scenarios A and B Scenarios C and D Elevation 35,786 km 600 km 1,200 km Spectrum (Service Link) <6 GHz (e.g., 2 GHz) > 6 GHz (e.g., DL 20 GHz, UL 30 GHz) Maximum Channel Bandwidth Capacity (Service Link) 30 MHz for band < 6 GHz 1 GHz for band > 6 GHz Maximum Distance between Satellite and Communication Node (e.g., UE) at Minimum Elevation Angle 40,581 km 1,932 km (600 km altitude) 3,131 km (1,200 km altitude) Maximum RTD (Round Trip Delay) (Propagation Delay Only) Scenario A: 541.46 ms (Service and Feeder Links) Scenario B: 270.73 ms (Service Link Only) Scenario C: (Transparent Payload: Service and Feeder Links) -25.77 ms (600 km Altitude) -41.77ms (1200km altitude) Maximum differential delay within a single cell 10.3ms 3.12ms (600km altitude) 3.18ms (1200km altitude) Service Link NR or 6G Feeder Link 3GPP or non-3GPP defined radio interface

[0120] In addition, in the NTN reference scenario defined in [Table 2], the delay constraint can be defined as shown in [Table 4] below.

[0121] Scenario A Scenario B Scenario C1-2 Scenario D1-2 Satellite Altitude 35,768 km 600 km Maximum RTD at radio interface between base station and UE 541.75 ms (Worst case) 270.57 ms 28.41 ms 12.88 ms Minimum RTD at radio interface between base station and UE 477.14 ms 238.57 ms 8 ms 4 ms

[0122] FIG. 10A is a conceptual diagram illustrating a first embodiment of a protocol stack of the user plane in a transparent payload-based non-terrestrial network, and FIG. 10B is a conceptual diagram illustrating a first embodiment of a protocol stack of the control plane in a transparent payload-based non-terrestrial network.

[0123] Referring to FIGS. 10A and 10B, user data can be transmitted and received between a UE and a core network (e.g., UPF), and control data (e.g., control information) can be transmitted and received between a UE and a core network (e.g., AMF). Each of the user data and control data can be transmitted and received via a satellite and / or gateway. The protocol stack of the user plane illustrated in FIG. 10A can be applied identically or similarly to a 6G communication network. The protocol stack of the control plane illustrated in FIG. 10B can be applied identically or similarly to a 6G communication network.

[0124] FIG. 11A is a conceptual diagram illustrating a first embodiment of a protocol stack of the user plane in a regenerative payload-based non-terrestrial network, and FIG. 11B is a conceptual diagram illustrating a first embodiment of a protocol stack of the control plane in a regenerative payload-based non-terrestrial network.

[0125] Referring to FIGS. 11A and 11B, user data and control data (e.g., control information), respectively, can be transmitted and received through an interface between the UE and a satellite (e.g., a base station). User data may refer to a user PDU (protocol data unit). A protocol stack of the SRI (satellite radio interface) can be used to transmit and receive user data and / or control data between the satellite and the gateway. User data can be transmitted and received through a GTP (general packet radio service (GPRS) tunneling protocol)-U tunnel between the satellite and the core network.

[0126] In relation to NTN communication, an NTN may be configured to provide non-terrestrial NR access to the UE through an NTN payload and an NTN gateway. A service link refers to the connection between the NTN payload and the UE, and a feeder link may refer to the link between the NTN gateway and the NTN payload.

[0127] FIG. 12 is a diagram illustrating an example of an NTN providing non-terrestrial NR access to a UE through an NTN payload and an NTN gateway. FIG. 12 shows a service link between the NTN payload and the UE and a feeder link between the NTN gateway and the NTN payload.

[0128] The NTN payload transparently transmits the wireless protocol received from the UE via the service link to the NTN gateway via the feeder link, or vice versa. Here, the connectivity supported by the NTN payload is as follows.

[0129] - An NTN gateway can provide multiple NTN payloads.

[0130] - A single NTN payload can be provided by multiple NTN gateways.

[0131] - The NTN payload can change the carrier frequency before retransmission on the service link, or vice versa (at each feeder link).

[0132] In NTN, the following may apply in addition to the network identifier.

[0133] - A tracking area corresponds to a fixed geographical area. Each mapping is configured in the RAN.

[0134] - Mapped cell ID defined in Section 16.14.5.

[0135] Three types of service links are supported.

[0136] - Earth-fixed: Service links can be provided by beam(s) that always continuously cover the same geographic area (e.g., GSO (Geosynchronous Orbit) satellites).

[0137] - Quasi-earth-fixed: Service links may be provided by beam(s) that cover one geographic area for a limited period and another geographic area for a different period (e.g., NGSO (non-GSO) satellites generating steerable beams).

[0138] - Earth-moving: Service links may be provided by beam(s) moving across the Earth's surface (e.g., NGSO satellites generating fixed beams or non-steeringable beams).

[0139] A gNB operating as an NGSO satellite can provide a quasi-Earth fixed service link or an Earth moving service link, and a gNB operating as a GSO satellite can provide an Earth fixed service link.

[0140] Timing and synchronization are as follows.

[0141] Regarding scheduling and timing, downlink and uplink frames are aligned using an offset given by NTA,offset (see Section 4.2 of TS 38.213) at the uplink time synchronization reference point (RP). To accommodate the propagation delay of NTN, some timing relationships are reinforced by a common timing advance (TA) and two offsets, K_offset and k_mac.

[0142] - Common TA is a timing offset configured to be equal to the round trip time (RTT) between the RP and NTN payloads.

[0143] - K offset is a configured scheduling offset that must be greater than or equal to the sum of the service link RTT and the common TA.

[0144] - k mac is an offset configured to be approximately equal to the RTT between RP and gNB.

[0145] Scheduling offset K offset is used to allow the UE sufficient processing time between downlink reception and uplink transmission (see TS 38.213). Offset k mac It is used to delay the application of the downlink configuration dictated by the MAC CE instruction in PDSCH (see TS 38.213) and for estimating the UE-gNB RTT (see TS 38.321). If downlink and uplink frame timings are not aligned at the gNB, offset k mac It can be provided by the network. Also, offset k mac It is used to determine the RAR window / MsgB window start time after Msg1 / MsgA transmission in random access procedures (see TS 38.213). Service link RTT, feeder link RTT, RP, common TA, k mac and TTA are as shown in Fig. 13.

[0146] Figure 13 is a diagram illustrating the timing relationship between objects included in NTN.

[0147] The network can configure HARQ operations as follows.

[0148] - For downlinks, HARQ feedback can be enabled or disabled on a per-HARQ process basis. Disabling HARQ feedback allows scheduling the HARQ process before one HARQ RTT has elapsed since the last scheduling.

[0149] - For uplinks, a HARQ mode (e.g., HARQ Mode A or HARQ Mode B) can be configured per HARQ process. HARQ Mode B allows scheduling a HARQ process before one HARQ RTT has elapsed since the last scheduling.

[0150] For HARQ processes configured to enable / disable HARQ feedback, it depends on the network implementation to ensure the appropriate HARQ feedback configuration (e.g., enable all or disable all) for the HARQ processes used in the SPS configuration. For HARQ processes configured in HARQ mode, it depends on the network implementation to ensure the appropriate HARQ mode configuration (e.g., all HARQ modes A or all HARQ modes B) for the HARQ processes used in the CG (configured grant) configuration.

[0151] The mobility and state transitions for NTN are as follows.

[0152] Regarding mobility in the RRC_IDLE and RRC_INACTIVE states, the same principles applied in TN (e.g., TS 38.300 Section 9.2.1) apply to mobility in RRC_IDLE for NTN, and the same principles applied in TN (e.g., TS 38.300 Section 9.2.2) may apply to mobility in RRC_INACTIVE for NTN.

[0153] The network can broadcast multiple tracking area codes (TACs) per public land mobile network (PLMN) from NR NTN cells. Changes to TACs within the system information are under network control, and changes to TACs may not be accurately synchronized with the real-time illumination of the ground beam.

[0154] In NTN-TN mobility, the network can broadcast cell information regarding NR TN and EUTRA TN coverage areas in SIB25. This is supported for ground-fixed, semi-ground-fixed, and ground-mobile cells. The coverage information consists of a list of geographic TN areas, and relevant frequency information is also indicated. The UE can skip TN measurements based on the broadcast TN coverage information.

[0155] The UE can implicitly determine the network type (e.g., ground or non-ground) through the presence of cellBarredNTN in SIB1. NTN ephemeris is provided in SIB19. An NTN cell may include the NTN payload ephemeris of the serving cell and, optionally, the NTN payload astronomical clock of an adjacent cell.

[0156] Mobility in RRC_CONNECTED can be examined in terms of handover, conditional handover (CHO), satellite switch with re-sync, and measurement.

[0157] With respect to handover, the same principles applied to TN (e.g., Section 9.2.3.2 of TS 38.300) may apply to NTN unless otherwise specified in the following description. During movement between NTN and TN, the UE is not required to connect to both NTN and TN simultaneously. NTN-TN handover implies bidirectional mobility, that is, movement from NTN to TN (e.g., hand-in) and from TN to NTN (e.g., hand-out). The UE may support mobility between gNBs operating with NTN payloads in different orbits (e.g., GSOs and NGSOs at different altitudes). NTN may support RACH-less handover.

[0158] With respect to conditional handover, the same principles applied in TN (e.g., TS 38.300 Section 9.2.3.4) may be applied to NTN unless otherwise specified in the following description. NTN supports radio resource management (RRM) measurement-based event A4, time-based trigger conditions, and / or location-based trigger conditions as additional trigger conditions that allow a UE to perform a conditional handover to a candidate cell.

[0159] Time-based or location-based trigger conditions may be configured independently of the measurement conditions for the NTN's conditional handover in the minimum hard satellite switch case where the service discontinuity gap time length is assumed to be zero or negligible. Otherwise, the time-based or location-based trigger conditions are configured together with one of the measurement-based trigger conditions (e.g., conditional handover events A3 / A4 / A5). How the UE evaluates the time-based or location-based trigger conditions together with the RRM measurement-based events depends on the UE implementation. When a time-based trigger condition is used, the source base station may signal the corresponding parameters to a single target gNB via the Source NG-RAN Node to Target NG-RAN Node Transparent Container during an NG-C based handover (see TS 23.502). The source base station may signal the corresponding conditional handover configuration to the UE using an RRC reconfiguration message during the handover. When a time-based trigger condition is used, the source base station determines the start time for the initial data delivery to the target base station by considering the time instructed to the UE. In addition, time-based conditional handover can be performed in a RACH-less manner.

[0160] Meanwhile, in the NTN, the base station may transmit system information (e.g., SIB19) containing satellite assistance information for NTN access. The UE may receive system information (e.g., SIB19) from the base station, verify the satellite assistance information included in the system information, and perform communication (e.g., non-terrestrial communication) based on the satellite assistance information.

[0161] The proposed technology relates to signaling and transmission methods related to the repeated transmission of PDCCH CSS for expanding NTN downlink coverage. Through this proposed technology, relevant information transmission and transmission methods are defined to support the repeated transmission of PDCCH CSS during the process in which terminals such as SIB1, SIB19, and Msg4 connect to a cell in the NTN downlink, thereby contributing to the expansion of NTN downlink coverage.

[0162] In the present disclosure, “terminal capability information” may be referred to in various ways, such as UE capability, UE capability information, UE capability information, terminal capability information, request information, request, terminal request information, UE Request, etc. In the same principle, “terminal capability information regarding repeated transmission” may be referred to in various ways, such as Repetition capability, Repetition request, etc.

[0163] In the present disclosure, “repeated transmission” may be referred to in various ways, such as Repetition, Repeated transmission, repeated transmission, or repetition.

[0164] In the present disclosure, “whether repeated transmission is performed” may be referred to in various ways, such as whether repeated transmission is supported, whether repeated transmission is enabled, enabling / disabling, enabled / disabled, etc.

[0165] In the present disclosure, “number of repeated transmissions” may be referred to in various ways, such as NrOfRepetitions, number of repetitions, repetition transmission factor, repetition transmission factor, Repetition factor, etc. For example, the number of Msg4 repeated transmissions may be referred to in various ways, such as NrOfMsg4Repetitions, etc.

[0166] The details regarding the downlink coverage enhancement of Phase 3 NTN currently being discussed in Rel-19 RAN WG1 are as shown in [Table 5] below.

[0167] The work item aims at specifying further enhancements for NG-RAN based NTN (Non-Terrestrial Networks) with the following assumptions:GSO (Geo Synchronous Orbit) and NGSO (Non-Geo Synchronous Orbit). NGSO includes Low Earth Orbit (LEO) and Medium Earth Orbit (MEO).Earth fixed tracking area. Earth fixed & Earth moving cells for NGSOFDD modeUEs with GNSS (Global Navigation Satellite Systems) capabilitiesIn frequency band above 10 GHz, both Terminal Type 1 (Electronic steering antenna) and Type 2 (Mechanical steering antenna) to be considered for GSO and NGSOImplicit compatibility to support HAPS (High Altitude Platform Station) and ATG (Air To Ground) scenarios, where relevantNote 1: In Rel-19 WID, "VSAT"device with external antenna on moving platform is equivalent to a device that operate on platforms in motion, and this is referred to as ESIM (Earth Station In Motion).The objectives of the work item are the following:Study and specifyif beneficialdownlink coverage enhancements targeting support for additional reference satellite payload parameters covering both GSO and NGSO constellations operating in FR1-NTN or FR2-NTN [RAN1, RAN2, RAN4]Define additional reference satellite payload parameters assuming power sharing among satellite beams or different satellite beam patterns / size (i.e. wide or narrow) across the satellite footprint, such that satellite beams may not all be simultaneously active or may be active below the nominal EIRP density per satellite beam (see section 6.1.1 in TR 38.821) due to limited power and limited feeder link bandwidth.Define the corresponding power sharing assumptions and necessary link level and system level evaluation methodology and relevant KPIs for evaluations of the coverage, to allow for identification of physical channels / signals and system-level aspects that need enhancements and the corresponding needed improvements.Study and if needed specify solutions, including link level enhancements for FR1-NTN (e.g. for PDCCH, PDSCH) and / or system level enhancements for FR1-NTN and / or FR2-NTN, allowing dynamic and flexible power sharing between satellite beams or different satellite beam patterns / size (i.e. wide or narrow) across the satellite footprint.RAN1 to report at the latest by RAN#106 with the list of targeted physical channels / signals for link level enhancements (if any), and with the targeted system-level enhancements (if any)RAN1 should report on impact to backward compatibility, if any, for potential extension of the SSB periodicity at the latest by RAN#106, in conjunction with the targeted system-level enhancements.Notes for this objective:SSB channel enhancement other than SSB periodicity extension is not consideredRAN1 should consider issues such as UE’s cell search complexity and impact to initial cell selection, latency and success rate, for the above extensionThe SSB periodicity enhancements potentially defined in this WID only apply to NTN operationAntenna gain of UE shall be assumed to be -5.5dBi in case of smartphone in FR1-NTN, the UE is assumed to be a full duplex UE, and at least 2Rx are considered at the UENGSO to be considered in priority: LEO Set-1 @ 600 kmRel-18 network energy saving techniques should be considered as baseline in the system level study.

[0168] As specified in the aforementioned WID, coverage enhancements for SSB, PDCCH, and PDSCH are being discussed to improve downlink coverage in Release 19. In this regard, downlink performance evaluations under various scenarios have been conducted since the RAN WG1 #116 meeting, and full-scale technology development began following the #118bis meeting. The technologies under discussion for improving downlink coverage can be subdivided as follows.

[0169] - SSB periodicity extension

[0170] Link level enhancement for PDCCH

[0171] - Link level enhancement for PDSCH carrying Msg4

[0172] - Link level enhancement for PDSCH carrying SIB1

[0173] The key approvals related to the present invention among the agreements of recent meetings (RAN1 #119 - #120) related to this are as shown in [Table 6] below.

[0174] RAN1 #119AgreementFor PDSCH with Msg4 Link level enhancement:Support PDSCH repetitionFFS: signalling design including number of repetitionsFFS: impact on UE capabilityNote: the target coverage enhancement to bridge the gap with respect to single Msg4 transmission is 2.8 dBFocus on coverage enhancement for set 1-3 with a target CNR of -8 dB for NR NTN DL coverage enhancements at link level.AgreementFor link level enhancement of PDSCH with SIB1:Support PDSCH repetitions within 20 ms durationThe number of repetitions is fixed to 2 repetitionsFurther discuss the specification impact for at least the following:Procedure and signaling (enabling repetitions, associated time resource determination, etc.)Note 1: without the above PDSCH repetitions, the coverage gap is 2.2 dB to 4.6 dB depending on SIB1 size.Note 2: Focus on coverage enhancement for set 1-3 with a target CNR of -8 dB for NR NTN DL coverage enhancements at link level.Note 3: the above is not related to multiple SIB1 transmissions across 20 ms periodicities of SSB, which may not be available when the SSB periodicity is 160 ms or larger (if supported) depending on the SSB and CORESET multiplexing pattern.AgreementFor PDCCH CSS (except Type-3) link level enhancements, support only PDCCH repetition for NTN.FFS: intra-slot and / or inter-slotRAN1 #120AgreementSupport only inter-slot repetition for Type0 PDCCH CSS.AgreementFor Msg4 PDSCH repetition support, RAN1 to consider:Option 1: UE specific repetition indication via DCIOption 2: Msg4 repetition is configured by SIB1Option 3: Msg4 PDSCH repetition is implicitly determined by SIB1 PDSCH repetitionAgreementAt least for enabling PDCCH repetition for Type0 PDCCH CSS ofsearchSpaceZeroconfigured within MIB pdcch-ConfigSIB1, RAN1 to consider the following optionsOption 1: Using the spare 1 bit in MIBOption 2: Using reserved bit(s) in PBCH payloadOption 3: Using codepoint(s) in PBCH payloadOption 4: UE blind decoding without signaling from the network during initial access.

[0175] Figure 14 is a diagram illustrating the uplink and downlink transmitted between the gNB and the UE during the initial cell connection.

[0176] In the present invention, a method is proposed for indicating (signaling) the repetition transmission factor (repetition factor or number of repetition) for Msg4 (currently under discussion at the standard conference) in FIG. 14.

[0177] [Proposal 1] Msg4 Repetition Argument Setting / Instruction

[0178] A connection between the UE and the gNB can be established through a random access procedure such as that shown in FIG. 14. At this time, repeated transmission of Msg4 may be performed, and signaling related to the repetition of Msg4 may be performed using at least one of the messages or signals transmitted and / or received prior to the transmission of Msg4.

[0179] The present proposal proposes multiple methods for setting the iteration factor for Msg4 (procedure [K]) in FIG. 14. The methods proposed below can perform the following procedures (processes 1 through 4) in common, wherein processes 1 through 3 may have different operations applied for each method presented below, and process 4 is the same for all methods. The description of process 4 below is omitted.

[0180] (Process 1) Pre-configuration for Msg4 Repetition (Base station terminal)

[0181] (Process 2) Report whether the terminal supports repeated transmission or request repeated transmission (terminal base station)

[0182] (Process 3) Setting the repeater for Msg4 Repetition or whether to enable / disabling repeat transmission (base station terminal)

[0183] (Process 4) PDSCH transmission with repeated transmission enabled / disabled (base station terminal)

[0184] Method 1: Reporting repetition capability and setting repetition factors

[0185] This method may not include settings related to repeated transmission in the pre-setting step of process 1. In process 2, the terminal reports to the base station whether it supports Msg4 repeated transmission, and based on this, in process 3, the base station sets the repeated transmission factor. Here, the repeated transmission factor refers to the number of repeated transmissions and can be a positive integer such as 1, 2, 4, or 8, and if set to 1, it means that repeated transmission is not performed. Subsequently, in process 2, the terminal reports to the base station whether it supports repeated transmission, and in process 3, the base station sets the repeated factor.

[0186] If the terminal reports in Step 2 that it supports repeat transmission, the base station transmits a Msg4 PDSCH with repeat transmission applied or a single Msg4 PDSCH (without repeat transmission applied) based on the repeat factor for Msg4 set in Step 3. If the terminal reports in Step 2 that it does not support repeat transmission, the terminal may not expect repeat transmission for Msg4. If the terminal does not report in Step 2 whether it supports repeat transmission, the terminal may not expect repeat transmission for Msg4.

[0187] Here, information reporting whether repetitive transmission is supported may, for example, simply indicate whether repetitive transmission is supported as positive or negative, or, for another example, indicate the number of supported repetitive transmissions. The number of supported repetitive transmissions may be indicated as 1, 2, 4, or 8. Alternatively, both the positive or negative indicator of repetitive transmission support and the number of supported repetitive transmissions may be transmitted as information reporting whether repetitive transmission is supported.

[0188] The above-described processes 2 and 3 may not be sequential. For example, the setup for process 3 may be performed first in Msg2, and the report for process 2 may be performed in Msg3.

[0189] Method 2: Repetition capability report and enabling / disabling repetition

[0190] The present method first pre-sets a repeat transmission factor in the pre-setting step of process 1, and can set a repeat transmission factor (NrOfMsg4Repetitions) such as 1, 2, 4, or 8. Then, in process 2, the terminal reports to the base station whether it supports repeat transmission, and in process 3, the base station sets whether to enable repeat transmission.

[0191] Here, information reporting whether repetitive transmission is supported may, for example, simply indicate whether repetitive transmission is supported as positive or negative, or, for another example, indicate the number of supported repetitive transmissions. The number of supported repetitive transmissions may be indicated as 1, 2, 4, or 8. Alternatively, both the positive or negative indicator of repetitive transmission support and the number of supported repetitive transmissions may be transmitted as information reporting whether repetitive transmission is supported.

[0192] If the terminal reports that it supports repeat transmission in process 2, the base station transmits a Msg4 PDSCH repeated NrOfMsg4Repetitions times or a single Msg4 PDSCH (without repeat transmission applied) based on whether the repeat is enabled for Msg4 set in process 3. If the terminal reports that it does not support repeat transmission in process 2, the terminal may not expect repeat transmission for Msg4 in process 3 (regardless of the base station's repeat transmission enable setting). If the terminal does not report whether it supports repeat transmission in process 2, the terminal may not expect repeat transmission for Msg4 in process 3 (regardless of the base station's repeat transmission enable setting).

[0193] The above-described Method 1 can be extended by omitting the report on whether the terminal supports repeated transmission (Process 2) in Method 1. If Process 2 is omitted, the base station may configure the system to perform repeated transmission assuming that the terminal supports Msg4 repeated transmission. If the terminal does not support repeated transmission, the terminal may attempt decoding using only the first (or any one) PDSCH of the repeatedly transmitted Msg4. On the other hand, if the terminal supports repeated transmission, the terminal may attempt decoding by receiving PDSCHs equal to the number of repeated transmissions. In this case, the terminal may attempt decoding by receiving all repeatedly transmitted PDSCHs, or by receiving and combining some of the repeatedly transmitted PDSCHs that the terminal supports.

[0194] The above-described processes 1, 2, and 3 may not be sequential. For example, the setup for process 3 may be performed first in Msg2, and the report for process 2 may be performed in Msg3.

[0195] Method 3: Repetition request and setting repetition arguments

[0196] This method may not include settings related to repeated transmission in the pre-setting step of process 1. In process 2, the terminal reports to the base station whether to request repeated transmission of Msg4, and based on this, in process 3, the base station sets the repeated transmission factor. Here, the repeated transmission factor represents the number of repeated transmissions and can be a positive integer such as 1, 2, 4, or 8, and if set to 1, it means that repeated transmission is not performed. Subsequently, in process 2, the terminal reports to the base station whether to request repeated transmission, and in process 3, the base station sets the repeated factor.

[0197] Here, information reporting whether a repeat transmission is requested may, for example, simply indicate whether a repeat transmission is requested as positive or negative, or, for another example, indicate the number of repeat transmissions requested. The number of repeat transmissions requested may be indicated as 1, 2, 4, or 8. Alternatively, both the positive or negative indicator of whether a repeat transmission is requested and the number of repeat transmissions requested may be transmitted as information reporting whether a repeat transmission is requested.

[0198] If the terminal requests a repeat transmission in process 2, the base station transmits a Msg4 PDSCH with repeat transmission applied or a single Msg4 PDSCH (without repeat transmission applied) based on the repeat factor for Msg4 set in process 3. If the terminal does not request a repeat transmission in process 2, the terminal may not expect a repeat transmission for Msg4.

[0199] In this method, in process 2 (described above), a terminal capable of receiving Msg4 repeated transmission (a terminal with Msg4 repetition capability) can request Msg4 repeated transmission, and a terminal without Msg4 repeated transmission capability does not request Msg4 repeated transmission.

[0200] Meanwhile, a terminal capable of receiving Msg4 repeated transmission may utilize a measurement (e.g., RSRP) obtained through a downlink signal (e.g., SSB or Msg2) and / or satellite orbit information (e.g., altitude, elevation angle, velocity, etc.) and / or its own location information (e.g., location information measured using GPS, etc.) as a condition for requesting Msg4 repeated transmission. In this case, if the number of repeated transmissions is included in the request for repeated transmission, the number of repeated transmissions requested by the terminal may be determined based on at least one of the measurement result, the satellite orbit, or the location information.

[0201] The processes 2 and 3 described above may not be sequential. For example, the configuration for process 3 may be performed first in Msg2, and the request for process 2 may be performed in Msg3.

[0202] In the above-described process 2, if the terminal requests repeated transmission from the base station, the base station may set repeated transmission (e.g., set the number of repetitions to 2 or more), or it may not set repeated transmission (e.g., set the number of repetitions to 1). That is, the base station may not necessarily have an obligation to provide repeated transmission in response to the terminal's request.

[0203] In the process 2 described above, when the terminal requests repeated transmission from the base station, the request for repeated transmission may include information on the number of required repeated transmissions.

[0204] Method 4: Setting Repetition Request and Enabling / Disabling Repetition

[0205] First, in the pre-setting step of process 1, the method pre-sets a repeat transmission factor, specifically, a repeat transmission factor (NrOfMsg4Repetitions) such as 1, 2, 4, or 8. Then, in process 2, the terminal reports to the base station whether to request Msg4 repeat transmission, and based on this, in process 3, the base station sets whether to enable repeat transmission.

[0206] Here, information reporting whether a repeat transmission is requested may, for example, simply indicate whether a repeat transmission is requested as positive or negative, or, for another example, indicate the number of repeat transmissions requested. The number of repeat transmissions requested may be indicated as 1, 2, 4, or 8. Alternatively, both the positive or negative indicator of whether a repeat transmission is requested and the number of repeat transmissions requested may be transmitted as information reporting whether a repeat transmission is requested.

[0207] If the terminal requests repeated transmission in Process 2, the base station transmits the repeatedly transmitted Msg4 based on the repetition factor for Msg4 set by the base station. If the terminal does not request repeated transmission in Process 2, the terminal may not expect repeated transmission of Msg4.

[0208] In this method, in process 2 (described above), a terminal capable of receiving Msg4 repeated transmission (a terminal with Msg4 repetition capability) can request Msg4 repeated transmission, and a terminal without Msg4 repeated transmission capability does not request Msg4 repeated transmission.

[0209] Meanwhile, a terminal capable of receiving Msg4 repeated transmission may utilize a measurement (e.g., RSRP) obtained through a downlink signal (e.g., SSB or Msg2) and / or satellite orbit information (e.g., altitude, elevation angle, velocity, etc.) and / or its own location information (location information measured using GPS, etc.) as a condition for requesting Msg4 repeated transmission. In this case, if the number of repeated transmissions is included in the request for repeated transmission, the number of repeated transmissions requested by the terminal may be determined based on at least one of the measurement result, the satellite orbit, or the location information.

[0210] In the above-described process 2, if the terminal requests a repeat transmission from the base station, the base station may enable repeat transmission (e.g., enable repeat transmission) or disable repeat transmission (e.g., disable repeat transmission).

[0211] For the above-described methods 1, 2, 3, and 4, the settings in process 1 can be performed via SIB1 or other SIBs (e.g., SIB19) or Msg2 RAR, and the information reported in process 2 and the information set in process 3 can be signaled through the following, respectively.

[0212] - Process 2: Msg3, Process 3: Msg4 scheduling DCI, or

[0213] - Process 2: Msg3, Process 3: Msg2 RAR PDSCH, or

[0214] - Process 2: Msg1, Process 3: Msg4 scheduling DCI, or

[0215] - Process 2: Msg1, Process 3: Msg2 RAR PDSCH

[0216] Here, whether repetitive transmission is supported or a repetitive transmission request via Msg1 may be signaled through the RO of the Msg1 Preamble. To this end, SIB1 or another SIB may include information (e.g., time or frequency axis position, count, etc.) about the RO associated with the indication to support repetitive transmission or request repetitive transmission.

[0217] Alternatively, whether repetitive transmission is supported or a repetitive transmission request via Msg1 may be signaled through the sequence value of the Msg1 Preamble. To this end, SIB1 or another SIB may include information about the sequence associated with the indication to support repetitive transmission or request repetitive transmission (e.g., sequence index, value used in the calculation of the sequence, etc.).

[0218] Regarding the above-described methods 1, 2, 3, and 4, processes 1, 2, and 3 may not be sequential. For example, the setup for process 3 may be performed first in Msg2, and the report for process 2 may be performed in Msg3.

[0219] Variation Method A: Set a single RSRP_threshold_Msg4_Rep and report the result of comparing it with the RSRP measured at the terminal.

[0220] Regarding the methods 1 through 4 described above, various modified methods can be considered, and through the modified method A (to be described below), modified methods 1A through 4A regarding the methods 1 through 4 described above can be considered. In process 1, a base station may pre-set a single RSRP_threshold_Msg4_Rep, and in process 2, a terminal may consider a method of reporting to the base station whether the RSRP_measurement measured based on the received downlink signal (e.g., SSB) exceeds the RSRP_threshold_Msg4_Rep. In this case, 1 bit of reporting information is required because the relationship between the RSRP_measurement and the RSRP_threshold_Msg4_Rep is reported.

[0221] In the variation method A described above, RSRP_threshold_Msg4_Rep may also be considered as not being set by the base station. For example, the value corresponding to RSRP_threshold_Msg4_Rep in this method may be given as a single fixed constant in the specification document. Alternatively, RSRP_threshold_Msg4_Rep may be set by the base station, but may be given as a single fixed constant as a default value. Yet another method may refer to another RSRP threshold value defined in existing standards (e.g., RSRP threshold for repeated transmission for Msg4 HARQ ACK / NAK) for the value corresponding to RSRP_threshold_Msg4_Rep.

[0222] In the modified method A described above, since the terminal reports the relationship between RSRP_measurement and RSRP_threshold_Msg4_Rep, the terminal may omit the repetition capability and / or repetition request and / or required number of repetition transmissions reported in Step 2 of Method 1-Method 4. The reason for this omission is that the report on the relationship between RSRP_measurement and RSRP_threshold_Msg4_Rep can replace the report on the repetition capability and / or repetition request and / or required number of repetition transmissions. That is, whether RSRP_measurement exceeds RSRP_threshold_Msg4_Rep can be used as information on whether repetition transmission is supported or requested (e.g., at least one of a positive / negative indication or the number of repetition transmissions).

[0223] In the modified method A described above, the base station may set a repeat transmission factor or repeat transmission activation for the terminal, with or without referring to the information reported by the terminal.

[0224] FIG. 15 is a diagram illustrating an example of a terminal reporting to a base station by identifying a range that includes RSRP measurements.

[0225] Variation Method B: Set two or three RSRP_threshold_Msg4_Rep(n) and report the result of comparing with the RSRP measured at the terminal.

[0226] Regarding the methods 1 through 4 described above, various modified methods can be considered, and through the modified method B (described below), modified methods 1B through 4B can be conceived for the methods 1 through 4 described above. For example, there may be a method in which a base station (in process 1) sets multiple RSRP_threshold_Msg4_Rep(n) (setting RSRP_threshold_Msg4_Rep(1) and RSRP_threshold_Msg4_Rep(2) when setting two, and setting RSRP_threshold_Msg4_Rep(1), RSRP_threshold_Msg4_Rep(2), and RSRP_threshold_Msg4_Rep(3) when setting three). Here, it can be assumed that RSRP_threshold_Msg4_Rep(n+1) is greater than or equal to RSRP_threshold_Msg4_Rep(n). The terminal can compare the RSRP_measurement measured based on the received downlink signal (e.g., SSB) with each RSRP_threshold_Msg4_Rep(n) to determine which RSRP range the measured RSRP belongs to, and can report this information (e.g., an index indicating the RSRP range). In an example such as FIG. 15, since the measured RSRP is a value between RSRP_threshold_Msg4_Rep(1) and RSRP_threshold_Msg4_Rep(2), it reports 1 as the RSRP_range value to the base station.

[0227] Similar to the variation method A described above, RSRP_threshold_Msg4_Rep(n=1,2,3) may also be considered in a way that is not set by the base station. For example, the value corresponding to RSRP_threshold_Msg4_Rep(n=1,2,3) of this method may be given as any fixed constant values ​​in the specification document. Alternatively, RSRP_threshold_Msg4_Rep may be set by the base station, but may be given as fixed constant values ​​as the default. Yet another way, the value corresponding to RSRP_threshold_Msg4_Rep may refer to other RSRP threshold values ​​defined in existing standards (e.g., RSRP threshold for repeated transmission of Msg4 HARQ ACK / NAK). Alternatively, only one value RSRP_threshold_Msg4_Rep(n=1) can be set, and the remaining values ​​RSRP_threshold_Msg4_Rep(n=2, 3) can be calculated as the differential value of RSRP, and the differential value of RSRP can be a fixed constant (e.g., 3dB) or determined through the base station settings.

[0228] In the modified method B described above, since the terminal reports the RSRP range for the measured RSRP, the terminal may omit the repetition capability and / or repetition request and / or required number of repetitions reported in Step 2 of Method 1-Method 4. The reason for this omission is that a report on the relationship between RSRP_measurement and RSRP_threshold_Msg4_Rep can replace the report on the repetition capability and / or repetition request and / or required number of repetitions. That is, information on which RSRP range RSRP_measurement belongs to can be used as information on whether repetitions are supported or requested (e.g., at least one of a positive / negative indication or the number of repetitions).

[0229] In the modified method B described above, the base station may set a repeat transmission factor or repeat transmission enable for the terminal, with or without referring to the RSRP_range information reported by the terminal.

[0230] Modification Method C: RSRP report measured at the terminal

[0231] Regarding the above-described methods 1 through 4, various modified methods may be considered, and through the modified method C (described below), modified methods 1C through 4C regarding the above-described methods 1 through 4 may be considered. For example, in process 2, the terminal may report an RSRP_measurement based on a downlink signal (e.g., SSB, Msg2) received. Here, the RSRP reported by the terminal may reuse the existing 7-bit format report, or the report may be performed by utilizing an RSRP report table with reduced report bits.

[0232] In the modified method C described above, since the terminal reports the measured RSRP, the terminal may omit the repetition capability and / or repetition request and / or required number of repetitions reported in Step 2 of Method 1-Method 4. The reason for this omission is that the RSRP report can replace the report on the repetition capability and / or repetition request and / or required number of repetitions. That is, RSRP_measurement can be used as information regarding whether repetitions are supported or requested (e.g., at least one of a positive / negative indication or the number of repetitions).

[0233] In the modified method C described above, the base station may set a repeat transmission factor or repeat transmission activation for the terminal, with or without referring to the information (RSRP) reported by the terminal.

[0234] Among the methods described above, the terminal's repetition capability to the base station encompasses all information that can directly or indirectly inform the base station of the terminal's repetition capability.

[0235] For all methods and variations described above, if the number of repetitions of a repeat transmission is fixed as a constant value (e.g., 2 times) in the standard specifications, some settings / reports, such as the repeat transmission factor signaled in steps 1-3 and the report of the required number of repeat transmissions, may be omitted. In this case, methods 1 and 3 are not meaningful methods because there are no settings that the base station instructs the terminal to. Meanwhile, methods 2 and 4 enable repeat transmissions as many times as the fixed value presented in the standard specifications by activating repeat transmission based on the Repetition capability or Repetition request reported by the terminal.

[0236] [Table 7] is a summary of the basic methods proposed in the present invention, Method 1-Method 4, and modified methods A-Method C for these methods.

[0237] Process 1 Process 2 Process 3 Method 1 - Repetition capability Repetition transmission argument Method 2 Repetition transmission argument Repetition capability Whether repetition is enabled Method 3 - Repetition request and / or required number of repetitions Repetition transmission argument Method 4 Repetition transmission argument Repetition request and / or required number of repetitions Whether repetition is enabled Variant Method A (Additional signaling) RSRP_threshold 1 (Additional signaling) Whether RSRP_threshold for measured RSRP is exceeded - Variant Method B (Additional signaling) RSRP_threshold 2-3 (Additional signaling) RSRP_range number for measured RSRP - Variant Method C (Additional signaling) Measured RSRP information -

[0238] [Proposal 2] PDCCH Repetition Argument Setting Signaling

[0239] PDCCH is transmitted over various types of Common Search Spaces, and each type is defined for the following purposes.

[0240] CSS Type0: DCI / PDCCH for SIB1 scheduling

[0241] CSS Type0A: DCI / PDCCH for other SIB scheduling

[0242] CSS Type1: DCI / PDCCH for Msg2 and Msg4 scheduling

[0243] CSS Type2: DCI / PDCCH for paging

[0244] CSS Type3: DCI / PDCCH for control information for a group of UEs

[0245] Among these, for CSS Type0 / 0A / 1 / 2, it was agreed that repeated PDCCH transmission is required, and settings related to repeated transmission of the PDCCH must be configured before the PDCCH of CSS Type0 scheduling this SIB1 is transmitted. The present invention proposes utilizing PBCH as follows to configure repeated transmission for the PDCCH.

[0246] Currently, PBCH has 2 bits of reserved bits for FR1 as shown in [Table 8], and since NTN prioritizes FR1, it can utilize the reserved bits of PBCH.

[0247] FR1FR2MIB24 bit24 bit PBCH excluding MIB and reserved bits bit30 bit32 bit PBCH reserved bits s2 bit0 bit

[0248] [Example 1] Use of 1-bit reserved bit

[0249] One bit of the PBCH reserved bit described above can be used to signal whether to repeat transmission for CSS Type 0 / 0A / 1 / 2 PDCCH. The transmitted information is 0 or 1, signifying repeat transmission disable and enable, respectively. Here, the repeat transmission parameter (e.g., number of repeat transmissions) can have an integer of 2 or more for each CSS Type, or it can be any single constant value defined for each type in the specification document. Alternatively, a single repeat parameter may be applied commonly to all types.

[0250] In the embodiment described above, repetitive transmission may be set for only some of the CSS Types by the reserved bit (mentioned above). For example, the PDCCH repetitive transmission for CSS Type0 and Type0A may be indicated using the PBCH reserved bit mentioned above. In this case, the setting of PDCCH repetitive transmission for the remaining Types may be indicated through other channels such as SIB1 or SIB19.

[0251] [Example 2] CSS type instruction to be repeatedly transmitted using 2 reserved bits

[0252] By using the 2 PBCH reserved bits described above, you can specify the CSS types for which recurrence is enabled. That is, for each code point, you can specify recurrence enablement for each CSS type. For example, for code point 00, PDCCH recurrence can be disabled for all types; for code point 01, PDCCH recurrence can be enabled only for Type 0; for code point 10, PDCCH recurrence can be enabled only for Type 0 / 0A / 1; and for code point 11, it can be left reserved. In other words, each code point can specify a combination of whether recurrence is enabled for each CSS type. In this case, the content of the combination corresponding to each code point may be fixedly predefined or determined by rules defined based on information included in the MIB information.

[0253] When repetitive transmission is enabled, the repetitive transmission parameters to be applied can be defined in the specification document for each type (e.g., fixed repetitive parameters), and in this case, the repetitive parameters for all types may be the same.

[0254] As in the example mentioned above, at least one type in which repeat transmission enable / disable is not set as the 2 bits of the (mentioned) PBCH can have repeat transmission enable set through SIB1 or SIB19 or other signaling.

[0255] [Example 3] Repetitive transmission setting using 2 reserved bits

[0256] By using the 2 PBCH reserved bits described above, up to four repeat transmission settings can be specified. For example, as shown in the table presented in [Table 3], up to four repeat transmission settings can be obtained using the PBCH reserved bits, and the number of repeat transmissions for each type can be specified for each code point. Here, the number of repeat transmissions for each type for each code point can be determined by rules defined based on information included in standard documents, etc., or information included in MIB or other system information.

[0257] In the case of [Table 9], code point 00 indicates that no PDCCH of any type performs repeated transmission, and code point 01 indicates that only Type 0 and Type 0A perform two repeated transmissions. Meanwhile, for Type 2, since the number of repeated transmissions for all code points is 1, it always means that no repeated transmission is performed, which means that Type 2 can be considered independent of the corresponding reserved bit.

[0258] Code pointType0Type0AType1Type2001111012211102221114221

[0259] FIG. 16 is a flowchart illustrating a method in which a terminal performs communication according to one embodiment of the present disclosure.

[0260] The operations disclosed in the flowchart of FIG. 16 may be performed in combination with various embodiments of the present disclosure. In one example, the operations disclosed in the flowchart of FIG. 16 may be performed based on at least one of the devices shown in FIG. 1A through FIG. 4. In one example, the terminal of FIG. 16 may correspond to the second communication node (400b) of FIG. 4, and the base station may correspond to the first communication node (400a) of FIG. 4. In another example, the terminal of FIG. 16 may correspond to the first communication node (400a) of FIG. 4, and the base station may correspond to the second communication node (400b) of FIG. 4. In another example, the terminal of FIG. 16 may correspond to at least one of the terminals shown in FIG. 1A through FIG. 3, and the base station may correspond to at least one of the base stations shown in FIG. 1A through FIG. 3.

[0261] In step S1601, a terminal according to one embodiment may transmit a random access preamble to a base station communicating with the terminal via a Non-Terrestrial Network (NTN).

[0262] In step S1602, a terminal according to one embodiment may receive a random access response associated with the random access preamble from the base station.

[0263] In step S1603, a terminal according to one embodiment can transmit capability information of the terminal to the base station based on the random access response.

[0264] The capability information of the above terminal may correspond to the UE capability, capability, UE capability information, UE capability information, etc. described throughout the present disclosure.

[0265] In step S1604, a terminal according to one embodiment can receive a PDSCH (Physical Downlink Shared Channel) repeated transmission by the base station based on the capability information.

[0266] In one embodiment, the capability information can be transmitted to the base station via PUSCH (Physical Uplink Shared Channel).

[0267] In one embodiment, the capability information may be included in the MSG3 for initial access and transmitted to the base station via the PUSCH.

[0268] In one embodiment, the capability information may indicate whether the terminal is capable of receiving the PDSCH repeated transmission.

[0269] In one embodiment, based on the capability information, whether to perform the PDSCH repeated transmission may be determined by the base station.

[0270] In one embodiment, the capability information may indicate the number of PDSCH repeated transmissions that the terminal can support.

[0271] In one embodiment, the number of PDSCH repeated transmissions that the terminal can support may be 1, 2, 4, or 8.

[0272] In one embodiment, through the PDSCH iterative transmission, an MSG4 for initial connection can be transmitted from the base station to the terminal.

[0273] According to one embodiment, the terminal can measure the Reference Signal Received Power (RSRP) based on a downlink signal received from the base station.

[0274] According to one embodiment, the terminal may transmit first comparison information between a pre-set first RSRP and the measured RSRP to the base station. The first comparison information may be at least one bit indicating whether the first RSRP is larger or the measured RSRP is larger.

[0275] According to one embodiment, the terminal may transmit second comparison information between a pre-set second RSRP, a pre-set third RSRP, and the measured RSRP to the base station. The third RSRP is greater than the second RSRP, and the second comparison information may be at least one bit indicating whether the measured RSRP is smaller than the second RSRP and the third RSRP, whether the measured RSRP is larger than the second RSRP and the third RSRP, or whether the measured RSRP is larger than the second RSRP and the third RSRP.

[0276] According to one embodiment, the terminal can transmit information representing the measured RSRP to the base station.

[0277] FIG. 17 is a flowchart illustrating a method in which a base station performs communication according to one embodiment of the present disclosure.

[0278] The operations disclosed in the flowchart of FIG. 17 may be performed in combination with various embodiments of the present disclosure. In one example, the operations disclosed in the flowchart of FIG. 17 may be performed based on at least one of the devices shown in FIG. 1A through FIG. 4. In one example, the terminal of FIG. 17 may correspond to the second communication node (400b) of FIG. 4, and the base station may correspond to the first communication node (400a) of FIG. 4. In another example, the terminal of FIG. 17 may correspond to the first communication node (400a) of FIG. 4, and the base station may correspond to the second communication node (400b) of FIG. 4. In another example, the terminal of FIG. 17 may correspond to at least one of the terminals shown in FIG. 1A through FIG. 3, and the base station may correspond to at least one of the base stations shown in FIG. 1A through FIG. 3.

[0279] In step S1701, a base station according to one embodiment may receive a random access preamble from a terminal communicating with the base station via an NTN. The random access preamble may represent the random access preamble transmitted by the terminal in step S1601.

[0280] In step S1702, a base station according to one embodiment may transmit a random access response associated with the random access preamble. The random access response may be received by the terminal in S1602.

[0281] In step S1703, a base station according to one embodiment may receive capability information of the terminal from the terminal based on the transmission of the random access response. The capability information of the terminal may represent capability information transmitted by the terminal in step S1603.

[0282] In step S1704, a base station according to one embodiment may transmit a PDSCH repeat transmission to the terminal based on the capability information. The PDSCH repeat transmission may be received by the terminal in step S1604.

[0283] In one embodiment, the capability information can be transmitted to the base station via PUSCH.

[0284] The methods according to the present disclosure may be implemented in the form of program instructions that can be executed through various computer means and recorded on a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, etc., alone or in combination. The program instructions recorded on the computer-readable medium may be those specifically designed and configured for the present disclosure, or they may be those known and available to those skilled in the art of computer software.

[0285] Examples of computer-readable media include hardware devices specifically configured to store and execute program instructions, such as ROM, RAM, and flash memory. Examples of program instructions include machine code, such as that produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter, etc.

[0286] Some aspects of the present disclosure have been described in the context of a device, but may also be described according to a corresponding method, wherein a block or device corresponds to a method step or a feature of a method step. Similarly, aspects described in the context of a method may also be described according to a corresponding block or item or a feature of a corresponding device. Some or all of the method steps may be performed by (or using) a hardware device, such as, for example, a microprocessor, a programmable computer, or an electronic circuit. In some embodiments, at least one of the important method steps may be performed by such a device.

[0287] A programmable logic device (e.g., a field-programmable gate array) may be used to perform some or all of the functions of the methods described in this disclosure. A field-programmable gate array may operate with a microprocessor to perform one of the methods described in this disclosure. Generally, it is preferable that the methods be performed by some hardware device.

[0288] Although the present invention has been described with reference to the embodiments above, those skilled in the art will understand that various modifications and changes can be made to the present disclosure without departing from the spirit and scope of the disclosure as set forth in the following claims.

Claims

1. In a method for a terminal to perform communication in a wireless communication system, A step of transmitting a random access preamble to a base station communicating with the terminal via an NTN (Non-Terrestrial Network); A step of receiving a random access response associated with the random access preamble from the base station; A step of transmitting capability information of the terminal to the base station based on the above random access response; and A method comprising the step of receiving a PDSCH (Physical Downlink Shared Channel) repeated transmission by the base station based on the above capability information.

2. In Paragraph 1, A method in which the above capability information is transmitted to the base station via PUSCH (Physical Uplink Shared Channel).

3. In Paragraph 2, A method in which the above capability information is included in MSG3 for initial access and transmitted to the base station via the above PUSCH.

4. In Paragraph 1, The above capability information indicates whether the terminal is capable of receiving the PDSCH repeated transmission, a method.

5. In Paragraph 4, A method in which, based on the above capability information, whether to perform the above PDSCH repeated transmission is determined by the base station.

6. In Paragraph 1, A method in which the above capability information indicates the number of PDSCH repeated transmissions that the terminal can support.

7. In Paragraph 6, A method in which the number of PDSCH repeated transmissions supported by the terminal is 1, 2, 4, or 8.

8. In Paragraph 1, A method in which an MSG4 for initial connection is transmitted from the base station to the terminal through the above PDSCH iterative transmission.

9. In Paragraph 1, A method further comprising the step of measuring the Reference Signal Received Power (RSRP) based on a downlink signal received from the base station.

10. In Paragraph 9, The method further includes the step of transmitting first comparison information between a pre-set first RSRP and the measured RSRP to the base station, The above first comparison information is at least one bit indicating whether the first RSRP is larger or the measured RSRP is larger, a method.

11. In Paragraph 9, The method further includes the step of transmitting second comparison information between a pre-set second RSRP, a pre-set third RSRP, and the measured RSRP to the base station, wherein The third RSRP is greater than the second RSRP, and A method in which the second comparison information is at least one bit indicating whether the measured RSRP is smaller than the second RSRP and the third RSRP, whether the measured RSRP is larger than the second RSRP and the third RSRP, or whether the measured RSRP is larger than the second RSRP and the third RSRP.

12. In Paragraph 9, A method further comprising the step of transmitting information representing the measured RSRP to the base station.

13. In a terminal that performs communication in a wireless communication system, At least one transceiver; At least one processor; and It includes at least one memory connected to operately with the above-mentioned at least one processor and storing instructions that control the terminal to perform operations when executed by the processor, and The above operations are, A step of transmitting a random access preamble to a base station communicating with the terminal via NTN; A step of receiving a random access response associated with the random access preamble from the base station; Based on the above random access response, the step of transmitting capability information of the terminal to the base station; and A terminal comprising the step of receiving a PDSCH iterative transmission by the base station based on the above capability information.

14. In Paragraph 13, The above capability information is a terminal transmitted to the base station via PUSCH.

15. In a base station performing communication in a wireless communication system, At least one transceiver; At least one processor; and It includes at least one memory connected to operately with the above-mentioned at least one processor and storing instructions that control the base station to perform operations when executed by the processor, and The above operations are, A step of receiving a random access preamble from a terminal communicating with the base station via NTN; A step of transmitting a random access response associated with the above random access preamble; Based on transmitting the above random access response, the step of receiving capability information of the terminal from the terminal; and A base station comprising the step of transmitting a PDSCH iterative transmission to the terminal based on the above capability information.

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