Method and device for repeated downlink transmissions 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: receiving first repeated transmissions of a physical downlink control channel (PDCCH) from a base station communicating with a terminal through a non-terrestrial network (NTN); receiving second repeated transmissions of the PDCCH from the base station; and receiving a physical downlink shared channel (PDSCH) related to the PDCCH from the base station, wherein the first repeated transmissions and the second repeated transmissions of the PDCCH may be received through consecutive slots or consecutive symbol sets.

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 technique for performing PDCCH repetitive transmission of an NTN downlink in the NTN.

[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 for aircraft, drones, satellites, and other non-terrestrial entities as well as those located on the ground, 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-terrestrial (e.g., an aircraft, a drone, 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 indicating and / or agreeing on whether to repeat transmission for a non-terrestrial network in a wireless communication system.

[0007] The present disclosure may provide a method and apparatus for performing repeated transmission of a PDCCH (physical downlink control channel) CSS (common search space) for a non-terrestrial network in a wireless communication system.

[0008] 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.

[0009] 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 comprises the steps of receiving a first iterative transmission of a Physical Downlink Control Channel (PDCCH) from a base station communicating with the terminal via a Non-Terrestrial Network (NTN), receiving a second iterative transmission of the PDCCH from the base station, and receiving a Physical Downlink Shared Channel (PDSCH) associated with the PDCCH from the base station, wherein the first iterative transmission and the second iterative transmission of the PDCCH may be received through consecutive slots or consecutive sets of symbols.

[0010] 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 include receiving a first iterative transmission of a PDCCH from a base station communicating with the terminal via an NTN, receiving a second iterative transmission of the PDCCH from the base station, and receiving a PDSCH associated with the PDCCH from the base station, wherein the first iterative transmission and the second iterative transmission of the PDCCH may be received through consecutive slots or consecutive sets of symbols.

[0011] 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 comprises the steps of transmitting a first iterative transmission of a PDCCH to a terminal communicating with the base station via an NTN, transmitting a second iterative transmission of the PDCCH to the terminal, and transmitting a PDSCH associated with the PDCCH to the terminal, wherein the first iterative transmission and the second iterative transmission of the PDCCH may be transmitted through consecutive slots or consecutive sets of symbols.

[0012] 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 include the steps of transmitting a first iterative transmission of a PDCCH to a terminal communicating with the base station via an NTN, transmitting a second iterative transmission of the PDCCH to the terminal, and transmitting a PDSCH associated with the PDCCH to the terminal, wherein the first iterative transmission and the second iterative transmission of the PDCCH may be transmitted through consecutive slots or consecutive sets of symbols.

[0013] According to one embodiment of the present disclosure, NTN downlink coverage can be improved.

[0014] 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.

[0015] FIGS. 1A and FIGS. 1B are conceptual diagrams illustrating some embodiments of a non-ground network.

[0016] FIGS. 2A to 2C are conceptual diagrams illustrating some embodiments of a non-ground network.

[0017] FIG. 3 is a block diagram illustrating a first embodiment of a communication node constituting a non-terrestrial network.

[0018] FIG. 4 is a block diagram illustrating a first embodiment of communication nodes performing communication.

[0019] 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.

[0020] FIG. 6 is a conceptual diagram illustrating an example of a system frame in a communication system.

[0021] FIG. 7 is a conceptual diagram illustrating an example of a subframe in a communication system.

[0022] FIG. 8 is a conceptual diagram illustrating an example of a slot in a communication system.

[0023] Figure 9 is a diagram showing the timing relationship between the uplink and downlink in a communication system.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] Figure 13 is a diagram illustrating the timing relationship between objects included in NTN.

[0028] FIG. 14 is a diagram illustrating an example of signaling in the NTN cell connection process of a terminal.

[0029] Figure 15 is a diagram illustrating an example of an MIB-based explicit instruction process.

[0030] Figure 16 is a diagram illustrating an example of a PBCH-based explicit instruction process.

[0031] FIG. 17 is a diagram illustrating an example of a process for performing an explicit instruction based on a PDCCH regarding SIB1.

[0032] Figure 18 is a diagram illustrating an example of an SIB-based explicit instruction process.

[0033] FIG. 19 is a diagram illustrating an example of a process for performing UE blind decoding without signaling.

[0034] Figure 20 is a diagram illustrating an example of slot-interval-based iterative transmission.

[0035] Figure 21 is a diagram illustrating an example of a symbol interval-based iterative transmission.

[0036] Figure 22 is a diagram illustrating an example of an iterative transmission based on an SSB index.

[0037] FIG. 23 is a flowchart illustrating a method in which a terminal performs communication according to one embodiment.

[0038] FIG. 24 is a flowchart illustrating a method in which a base station performs communication according to one embodiment.

[0039] 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 comprises the steps of receiving a first iterative transmission of a Physical Downlink Control Channel (PDCCH) from a base station communicating with the terminal via a Non-Terrestrial Network (NTN), receiving a second iterative transmission of the PDCCH from the base station, and receiving a Physical Downlink Shared Channel (PDSCH) associated with the PDCCH from the base station, wherein the first iterative transmission and the second iterative transmission of the PDCCH may be received through consecutive slots or consecutive sets of symbols.

[0040] 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.

[0041] 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.

[0042] 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".

[0043] 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".

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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)).

[0051] 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."

[0052] 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.

[0053] 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."

[0054] 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.

[0055] 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.

[0056] 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.

[0057] In NTN, three types of service links can be supported as follows.

[0058] - Earth-fixed: Service links can be provided by beam(s) that always continuously cover the same geographic area (e.g., GSO (Geosynchronous Orbit) satellites)

[0059] - 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).

[0060] - 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)

[0061] 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 specifications, 5G specifications, and / or 6G specifications.

[0062] 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.

[0063] 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).

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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).

[0070] As in the embodiments of FIGS. 2B and FIG. 2C, a core network may exist between the gateway (230) and the data network (240).

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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).

[0075] 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).

[0076] 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.

[0077] 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.

[0078] 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 a 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).

[0079] 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.

[0080] 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.

[0081] 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).

[0082] 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.

[0083] 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).

[0084] 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).

[0085] 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.

[0086] 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).

[0087] 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).

[0088] 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.

[0089] 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.

[0090] 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.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] 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.

[0095] 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.

[0096] FIG. 6 is a conceptual diagram illustrating an example of a system frame in a communication system.

[0097] 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.

[0098] 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".

[0099] FIG. 7 is a conceptual diagram illustrating an example of a subframe in a communication system.

[0100] 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.

[0101] FIG. 8 is a conceptual diagram illustrating an example of a slot in a communication system.

[0102] 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.

[0103] 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.

[0104] 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

[0105] 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.

[0106] 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.

[0107] 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."

[0108] Figure 9 is a diagram showing the timing relationship between the uplink and downlink in a communication system.

[0109] 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.

[0110] 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.

[0111] 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.

[0112] 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.

[0113] As described above, the timing of the downlink and uplink can be adjusted based on the transmission timing adjustment of the synchronization procedure.

[0114] 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.

[0115] 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 configuration information received from the base station and determine uplink transmission power. Then, the terminal can transmit a PUSCH using the determined power through the identified resources.

[0116] 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.

[0117] 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.

[0118] Meanwhile, NTN reference scenarios can be defined as shown in [Table 2] below.

[0119] 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

[0120] 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”.

[0121] 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".

[0122] The parameters for the NTN reference scenarios defined in [Table 2] can be defined as shown in [Table 3] below.

[0123] 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

[0124] In addition, in the NTN reference scenario defined in [Table 2], the delay constraint can be defined as shown in [Table 4] below.

[0125] 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

[0126] 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.

[0127] 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.

[0128] 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.

[0129] 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.

[0130] 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.

[0131] 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.

[0132] 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.

[0133] - An NTN gateway can provide multiple NTN payloads.

[0134] - A single NTN payload can be provided by multiple NTN gateways.

[0135] - The NTN payload can change the carrier frequency before retransmission on the service link, or vice versa (at each feeder link).

[0136] In NTN, the following may apply in addition to the network identifier.

[0137] - A tracking area corresponds to a fixed geographical area. Each mapping is configured in the RAN.

[0138] - Mapped cell ID defined in Section 16.14.5.

[0139] Three types of service links are supported.

[0140] - Earth-fixed: Service links can be provided by beam(s) that always continuously cover the same geographic area (e.g., GSO (Geosynchronous Orbit) satellites).

[0141] - 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).

[0142] - 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).

[0143] 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.

[0144] Timing and synchronization are as follows.

[0145] 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.

[0146] - Common TA is a timing offset configured to be equal to the round trip time (RTT) between the RP and NTN payloads.

[0147] - 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.

[0148] - k mac is an offset configured to be approximately equal to the RTT between RP and gNB.

[0149] 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.

[0150] Figure 13 is a diagram illustrating the timing relationship between objects included in NTN.

[0151] The network can configure HARQ operations as follows.

[0152] - 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.

[0153] - 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.

[0154] 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.

[0155] The mobility and state transitions for NTN are as follows.

[0156] 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.

[0157] 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.

[0158] 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.

[0159] 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.

[0160] Mobility in RRC_CONNECTED can be examined in terms of handover, conditional handover (CHO), satellite switch with re-sync, and measurement.

[0161] 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.

[0162] 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.

[0163] 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.

[0164] 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.

[0165] 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.

[0166] In the present disclosure, "repetitive transmission" may be referred to in various ways, such as Repetition, Repeated transmission, etc.

[0167] In the present disclosure, the term "repetition factor" may be referred to in various ways, such as a repetition factor, a repetition factor, a repetition transmission factor, information regarding repetition transmission, or information regarding the number of PDCCH repetition transmissions.

[0168] In the present disclosure, "repetition enable / disable" may be referred to in various ways, such as Repetition Enabled / Disabled, information regarding repetitive transmission, or information regarding whether PDCCH repetitive transmission is performed.

[0169] In the present disclosure, the "time scaling factor" may be referred to in various ways, such as slot scaling factor, M, etc.

[0170] In the present disclosure, "blind decoding" may be referred to in various ways, such as Blind decoding, BD, etc.

[0171] In the present disclosure, "terminal capability information" may be referred to in various ways, such as UE capability, UE capability information, UE capability information, request, request information, request, etc.

[0172] In the present disclosure, "Type N (wherein N is 0, 0A, 1, 2 or 3) PDCCH CSS" may be referred to in various ways, such as Type N PDCCH CSS, Type N CSS PDCCH, Type-N CSS PDCCH, Type-N PDCCH CSS, etc.

[0173] Cells supported by NTN (non-terrestrial network) base stations have a wider radius compared to cells supported by conventional TN (terrestrial network) stations. Additionally, in NTN, the distance from a terminal to a base station or to a satellite relaying signals between a base station and a terminal becomes relatively much longer than the distance from a terminal to a base station in TN. Accordingly, to increase coverage in both the uplink and downlink environments of NTN cells, repetition transmission, in which a specific symbol is transmitted multiple times across multiple time / frequency resources, may be applied.

[0174] FIG. 14 is a diagram illustrating an example of signaling in the NTN cell connection process of a terminal.

[0175] Various discussions are currently underway to increase the coverage of the NTN downlink covered in the Release-19 standardization. Among these, as shown in Fig. 14, discussions are being held regarding the repeated transmission of the PDSCH (Physical Downlink Shared Channel) and the PDCCH (Physical Downlink Control Channel) received during the process of a terminal connecting to a cell. In particular, regarding the repeated transmission of the PDCCH, discussions are being held regarding the repeated transmission of Type 0, Type 0A, Type 1, and Type 2-PDCCH CSS (Common Search Space).

[0176] Since the Repetition Factor of such PDCCH CSS repeated transmission is considered to be 2, in order to support PDCCH CSS repeated transmission, it is necessary for the base station and the terminal to commonly understand or agree on the method before PDCCH CSS repeated transmission by transmitting information regarding whether to repeat transmission through Explicit Signaling, etc., or through methods / information via standards. Along with this, when repeated transmission is performed, it is necessary to determine the repeated transmission method (e.g., Inter-slot repetition / Intra-slot repetition), such as the time resources to be used for the second transmission of the repeated transmission. Accordingly, the present invention proposes signaling transmission / agreement methods and repeated transmission procedures to support such PDCCH CSS repeated transmission.

[0177] Each of the techniques proposed below can be applied in conjunction with other techniques to separately indicate whether multiple PDCCH CSSs are transmitted repeatedly. For example, different detailed methods in Proposal 1 can be used to convey whether Type0 PDCCH CSS and Type1 PDCCH CSS are transmitted repeatedly, and different detailed methods in Proposal 2 can also be applied to Type0 PDCCH CSS and Type1 PDCCH CSS.

[0178] [Proposal 1: Indication / Agreement of Repetition Enabled / Disabled for PDCCH CSS]

[0179] Proposal 1 presents methods for indicating / agreeing on whether to repeat transmission.

[0180] [Proposal 1-1: MIB Based Explicit Indication]

[0181] Figure 15 is a diagram illustrating an example of an MIB-based explicit instruction process.

[0182] Proposal 1-1 proposes a method in which the repeatability of transmission is explicitly indicated via the Reserved Bit of the Master Information Block (MIB), as shown in Fig. 15. In this method, the repeatability of transmission can be indicated by utilizing a field corresponding to the 1-bit Spare Bit within the 23-bit MIB based on the current Release-18 standard. In this case, the information corresponding to the Bit 0 / Bit 1 mapping based on the 1-bit Spare Bit can be defined according to standard specifications. (e.g., Bit 0 – Disabled / Bit 1 – Enabled, Bit 0 – Enabled, Bit 1 – Disabled)

[0183] If a Repetition Factor greater than 2 is supported for the repeated transmission of PDCCH CSS through the standard specification, two Repetition Factors may be indicated instead of Repetition Disabled / Enabled using 1 bit, in which case the Repetition Factor corresponding to the Bit 0 / Bit 1 Mapping may be defined according to the standard specification. (e.g., Bit 0 - No Repetition / Bit 1 – Repetition Factor 2, Bit 0 - No Repetition / Bit 1 – Repetition Factor 4) In addition, if the number of MIB bits is extended, a Repetition Factor greater than 2 may be indicated through the use of a new bit field, in which case the Repetition Factor corresponding to each Bit Mapping may be defined according to the standard specification. Alternatively, the Repetition Factor may be transmitted via the MIB, and Repetition Enabled / Disabled may be transmitted separately for individual or multiple PDCCH CSS Types; in this case, each terminal can determine whether each PDCCH CSS Type is repeatedly transmitted via a separate message, and if Repetition is applied, apply the Repetition Factor identified via the MIB. Alternatively, Repetition Enabled / Disabled may be transmitted via the MIB, and the Repetition Factor may be transmitted or defined separately for individual or multiple PDCCH CSS Types; in this case, each terminal can determine whether each PDCCH CSS Type is repeatedly transmitted via the MIB, and then separately identify and apply the Repetition Factor to be applied at that time.Alternatively, Repetition Enabled / Disabled and Repetition Factor can be defined as separate fields and all passed through the MIB.

[0184] When an Explicit Indication of whether to repeat transmission is performed via MIB, the relevant information may be applied to PDCCH CSS Types that must be received after MIB transmission / reception. Therefore, the retransmission of Type0 PDCCH CSS may be indicated by an Explicit Indication via MIB, or the retransmission of Type0A PDCCH CSS may be indicated by an Explicit Indication via MIB, or the retransmission of Type1 PDCCH CSS may be indicated by an Explicit Indication via MIB, or the retransmission of Type2 PDCCH CSS may be indicated by an Explicit Indication via MIB, or the retransmission of Type0 / 0A PDCCH CSS may be indicated at once by an Explicit Indication via MIB, or the retransmission of Type0 / 1 PDCCH CSS may be indicated at once by an Explicit Indication via MIB, or the retransmission of Type0 / 2 PDCCH CSS may be indicated at once by an Explicit Indication via MIB, or the retransmission of Type0A / 1 PDCCH CSS may be indicated at once by an Explicit Indication via MIB, or in the Explicit Indication via MIB The recurring transmission of Type0A / 2 PDCCH CSS may be indicated at once, or the recurring transmission of Type1 / 2 PDCCH CSS may be indicated at once by an Explicit Indication via MIB, or the recurring transmission of Type0 / 0A / 1 PDCCH CSS may be indicated at once by an Explicit Indication via MIB, andAlternatively, whether Type0 / 0A / 2 PDCCH CSS is to be transmitted repeatedly may be indicated at once by an Explicit Indication via an MIB, or whether Type0 / 1 / 2 PDCCH CSS is to be transmitted repeatedly may be indicated at once by an Explicit Indication via an MIB, or whether Type0A / 1 / 2 PDCCH CSS is to be transmitted repeatedly may be indicated at once by an Explicit Indication via an MIB, or whether Type0 / 0A / 1 / 2 PDCCH CSS is to be transmitted repeatedly may be indicated at once by an Explicit Indication via an MIB. Among the PDCCH CSS Types transmitted after the delivery of the MIB containing PDCCH CSS repeated transmission information, which PDCCH CSS Type(s) perform repeated transmission based on said information may be defined by the standard specification.

[0185] In this case, if repeated transmission is supported for multiple PDCCH CSS types, it is possible to define whether to repeat transmission only for a specific PDCCH CSS type, and define the repetition of the remaining PDCCH CSS types as being determined in the same way. For example, it is possible to define whether to repeat transmission for Type0 PDCCH CSS by indicating it via an MIB, and to determine that the repetition of Type0A / 1 / 2 PDCCH CSS operates identically to the repetition indication for Type0 PDCCH CSS. In other words, the repetition of transmission for multiple types of PDCCH CSS can be indicated through the same bit field.

[0186] In this case, if the repeatability of multiple types of PDCCH CSS is supported using the same field, the mapping for the repeatability of each PDCCH CSS type may be defined differently for the same bit value. For example, Repetition Enabled / Disabled is indicated by the same bit field for Type 0, 0A, 1, and 2, and the interpretation of Enabled / Disabled for bits 0 and 1 may be determined differently depending on each Type. The definition of such mapping may be determined by standard specifications.

[0187] The terminal receives the MIB to determine whether to repeat transmission, and then proceeds with the reception process by assuming that repeated transmission is in progress according to the instructions for the PDCCH CSS Type(s) defined as applying the instructions according to standard specifications. The terminal may proceed with subsequent procedures accordingly, depending on whether decoding is successful or unsuccessful during the reception process.

[0188] In this method, information regarding the use of time / frequency resources (repetition interval, Time / Frequency Resource Mapping, etc.) in repeated transmission can be considered to be standardized or transmitted via separate signaling. For example, when Inter-Slot Repetition is applied, the terminal can expect to receive PDCCH CSS in a number of available slots equal to the number of repeated transmissions, which is 2 slots, including at least the first slot that received the PDCCH CSS.

[0189] [Proposal 1-2: PBCH Based Explicit Indication]

[0190] Figure 16 is a diagram illustrating an example of a PBCH-based explicit instruction process.

[0191] Proposal 1-2 proposes a method, as shown in Fig. 16, in which the repeat transmission status is explicitly indicated through the Reserved Bits of the Physical Broadcast Channel (PBCH) Payload, excluding the MIB. In this method, the repeat transmission status can be indicated by utilizing a field corresponding to one of the 2 Reserved Bits in FR1 based on the current Release-18 standard. In this case, the information corresponding to the Bit 0 / Bit 1 mapping based on a 1-bit basis can be defined according to standard specifications. (e.g., Bit 0 – Disabled / Bit 1 – Enabled, Bit 0 – Enabled, Bit 1 – Disabled)

[0192] If a Repetition Factor greater than 2 is supported for the repeated transmission of PDCCH CSS through the standard specification, instead of using 1 bit to indicate Repetition Disabled / Enabled, 2 Repetition Factors may be indicated, whereby the Repetition Factor corresponding to the Bit 0 / Bit 1 Mapping may be defined according to the standard specification. (e.g., Bit 0 - No Repetition / Bit 1 – Repetition Factor 2, Bit 0 - No Repetition / Bit 1 – Repetition Factor 4) Alternatively, 2 bits may be used to indicate the Repetition Factor. (e.g., Bit 00 – No Repetition / Bit 01 – Repetition Factor 2 / Bit 10 – Repetition Factor 4 / Bit 11 – Repetition Factor 8) In addition, if the number of PBCH Payload bits is expanded, a Repetition Factor exceeding 4 can be indicated by using a new bit field, and in this case, the Repetition Factor corresponding to each Bit Mapping can be defined according to standard specifications. Alternatively, the Repetition Factor can be transmitted via the PBCH Payload and Repetition Enabled / Disabled can be transmitted separately for individual or multiple PDCCH CSS Types, in which case each terminal can determine whether each PDCCH CSS Type is being transmitted repeatedly through a separate message, and if Repetition is applied, apply the Repetition Factor determined via the PBCH Payload.Alternatively, Repetition Enabled / Disabled may be transmitted via the PBCH Payload, and the Repetition Factor may be transmitted or defined separately for individual or multiple PDCCH CSS Types; in this case, each terminal can determine whether each PDCCH CSS Type is being repeatedly transmitted via the PBCH Payload, and then separately identify and apply the Repetition Factor to be used at that time. Alternatively, Repetition Enabled / Disabled and the Repetition Factor may be defined as separate fields and both transmitted via the PBCH Payload.

[0193] If an explicit indication of whether to repeat transmission is performed via the PBCH payload, the relevant information may be applied to PDCCH CSS types that must be received after the PBCH payload is delivered or received. Therefore, the re-transmission of Type0 PDCCH CSS may be indicated by an Explicit Indication via the PBCH Payload, or the re-transmission of Type0A PDCCH CSS may be indicated by an Explicit Indication via the PBCH Payload, or the re-transmission of Type1 PDCCH CSS may be indicated by an Explicit Indication via the PBCH Payload, or the re-transmission of Type2 PDCCH CSS may be indicated by an Explicit Indication via the PBCH Payload, or the re-transmission of Type0 / 0A PDCCH CSS may be indicated at once by an Explicit Indication via the PBCH Payload, or the re-transmission of Type0 / 1 PDCCH CSS may be indicated at once by an Explicit Indication via the PBCH Payload, or the re-transmission of Type0 / 2 PDCCH CSS may be indicated at once by an Explicit Indication via the PBCH Payload, or Type0A / 1 The recurrence of PDCCH CSS may be indicated at once, or the recurrence of Type0A / 2 PDCCH CSS may be indicated at once by an Explicit Indication via a PBCH Payload, or the recurrence of Type1 / 2 PDCCH CSS may be indicated at once by an Explicit Indication via a PBCH Payload,Alternatively, whether to re-transmit Type0 / 0A / 1 PDCCH CSS may be indicated at once by an Explicit Indication via the PBCH Payload, or whether to re-transmit Type0 / 0A / 2 PDCCH CSS may be indicated at once by an Explicit Indication via the PBCH Payload, or whether to re-transmit Type0 / 1 / 2 PDCCH CSS may be indicated at once by an Explicit Indication via the PBCH Payload, or whether to re-transmit Type0A / 1 / 2 PDCCH CSS may be indicated at once by an Explicit Indication via the PBCH Payload, or whether to re-transmit Type0 / 0A / 1 / 2 PDCCH CSS may be indicated at once by an Explicit Indication via the PBCH Payload. Whether which PDCCH CSS Type(s) among the PDCCH CSS Types transmitted after the delivery of the PBCH Payload containing PDCCH CSS re-transmission information performs re-transmission based on said information may be defined by the standard specification.

[0194] In this case, if repeated transmission is supported for multiple PDCCH CSS types, it is possible to define whether to repeat only for a specific PDCCH CSS type, and define the repetition of the remaining PDCCH CSS types as being determined in the same way. For example, the repetition of Type0 PDCCH CSS can be defined by indicating it via the PBCH Payload, and the repetition of Type0A / 1 / 2 PDCCH CSS can be determined to operate in the same manner as the repetition instruction for Type0 PDCCH CSS. In other words, the repetition of multiple types of PDCCH CSS can be indicated through the same bit field.

[0195] In this case, if the repeatability of multiple types of PDCCH CSS is supported using the same field, the mapping for the repeatability of each PDCCH CSS type may be defined differently for the same bit value. For example, Repetition Enabled / Disabled is indicated by the same bit field for Type 0, 0A, 1, and 2, and the interpretation of Enabled / Disabled for bits 0 and 1 may be determined differently depending on each Type. The definition of such mapping may be determined by standard specifications.

[0196] The terminal receives the PBCH Payload, determines whether to repeat transmission, and then proceeds with the reception process by assuming that repeated transmission proceeds according to the instructions for the PDCCH CSS Type(s) defined to apply the instructions according to standard specifications. The terminal may proceed with subsequent procedures accordingly, depending on whether decoding is successful or unsuccessful during the reception process.

[0197] In this method, information regarding the use of time / frequency resources (repetition interval, Time / Frequency Resource Mapping, etc.) in repeated transmission can be considered to be standardized or transmitted via separate signaling. For example, when Inter-Slot Repetition is applied, the terminal can expect to receive PDCCH CSS in a number of available slots equal to the number of repeated transmissions, which is 2 slots, including at least the first slot that received the PDCCH CSS.

[0198] [Proposal 1-3: PDCCH Based Explicit Indication regarding SIB1]

[0199] FIG. 17 is a diagram illustrating an example of a process for performing an explicit instruction based on a PDCCH regarding SIB1.

[0200] Proposal 1-3 proposes a method in which the repetitive transmission status is explicitly indicated, as shown in Fig. 17, through the PDCCH for SIB1, i.e., DCI (Downlink Control Information) format 1_0 with CRC (Cyclic Redundancy Check) scrambled by SI (System Information)-RNTI (Radio Network Temporary Identifier). Since the DCI currently has 15 or 17 bits of reserved bits depending on the Release-18 standard frequency band, a new bit field can be defined in that area to indicate the repetitive transmission status. In this case, the information corresponding to the Bit 0 / Bit 1 mapping based on a 1-bit basis can be defined according to standard specifications. (e.g., Bit 0 – Disabled / Bit 1 – Enabled, Bit 0 – Enabled, Bit 1 – Disabled)

[0201] If a Repetition Factor greater than 2 is supported for the repeated transmission of PDCCH CSS through the standard specification, instead of using 1 bit to indicate Repetition Disabled / Enabled, 2 Repetition Factors may be indicated, whereby the Repetition Factor corresponding to the Bit 0 / Bit 1 Mapping may be defined according to the standard specification. (e.g., Bit 0 - No Repetition / Bit 1 – Repetition Factor 2, Bit 0 - No Repetition / Bit 1 – Repetition Factor 4) Alternatively, 2 bits may be used to indicate the Repetition Factor. (e.g., Bit 00 – No Repetition / Bit 01 – Repetition Factor 2 / Bit 10 – Repetition Factor 4 / Bit 11 – Repetition Factor 8) or, the Repetition Factor may be transmitted via the PDCCH regarding SIB1 and Repetition Enabled / Disabled may be transmitted separately for individual or multiple PDCCH CSS Types, in which case each terminal may determine whether each PDCCH CSS Type is repeatedly transmitted via a separate message and, if Repetition is applied, apply the Repetition Factor determined via the PDCCH regarding SIB1. Or, Repetition Enabled / Disabled may be transmitted via the PDCCH regarding SIB1 and the Repetition Factor may be transmitted or defined and used separately for individual or multiple PDCCH CSS Types, in which case each terminal may determine whether each PDCCH CSS Type is repeatedly transmitted via the PDCCH regarding SIB1 and, at that time, determine and apply the Repetition Factor to be applied separately.Alternatively, Repetition Enabled / Disabled and Repetition Factor can be defined as separate fields and all transmitted via the PDCCH for SIB1.

[0202] When an Explicit Indication of whether to repeat transmission via PDCCH regarding SIB1 is performed, the information may be applied to PDCCH CSS Types that must be received after the transmission / reception of the PDCCH (DCI format 1_0 with CRC scrambled by SI-RNTI). Therefore, the re-transmission of Type0A PDCCH CSS may be indicated by an Explicit Indication via PDCCH regarding SIB1, or the re-transmission of Type1 PDCCH CSS may be indicated by an Explicit Indication via PDCCH regarding SIB1, or the re-transmission of Type2 PDCCH CSS may be indicated by an Explicit Indication via PDCCH regarding SIB1, or the re-transmission of Type0A / 1 PDCCH CSS may be indicated at once by an Explicit Indication via PDCCH regarding SIB1, or the re-transmission of Type0A / 2 PDCCH CSS may be indicated at once by an Explicit Indication via PDCCH regarding SIB1, or the re-transmission of Type1 / 2 PDCCH CSS may be indicated at once by an Explicit Indication via PDCCH regarding SIB1, or the re-transmission of Type0A / 1 / 2 PDCCH CSS may be indicated by an Explicit Indication via PDCCH regarding SIB1. Whether or not can be indicated at once. Thus, whether which PDCCH CSS Type(s) among the PDCCH CSS Types transmitted after the delivery of the PDCCH regarding SIB1 containing PDCCH CSS iteration transmission information performs iteration transmission based on said information can be defined by the standard specification.

[0203] In this case, if repeated transmission is supported for multiple PDCCH CSS types, the repeatability for a specific PDCCH CSS type can be defined in a single field (a single specific bit), and the repeatability for the remaining PDCCH CSS types can be defined in the same way. For example, the repeatability for Type0A PDDCH CSS can be defined as being indicated via the PDCCH related to SIB1, and the repeatability for Type1 / 2 PDCCH CSS can be determined to operate identically to the repeatability instruction for Type0 PDCCH CSS. In other words, the repeatability for multiple types of PDCCH CSS can be indicated through the same bit field. Alternatively, if repeated transmission is supported for multiple PDCCH CSS types, a separate bit (field) can be applied to each PDDCH CSS type to indicate the repeatability for each separately.

[0204] In this case, if the repeatability of multiple types of PDCCH CSS is supported using the same field, the mapping for the repeatability of each PDCCH CSS type may be defined differently for the same bit value. For example, for Type 0A, 1, and 2, Repetition Enabled / Disabled is indicated by the same bit field, and the interpretation of Enabled / Disabled for bits 0 and 1 may be determined differently depending on each type. The definition of such mapping may be determined by standard specifications.

[0205] The terminal receives a PDCCH regarding SIB1 to determine whether to repeat transmission, and then proceeds with the reception process by assuming that repeated transmission is in progress according to the instructions for the PDCCH CSS Type(s) defined as applying the instructions according to standard specifications. Depending on whether decoding is successful or unsuccessful during the reception process, the terminal may proceed with the corresponding subsequent procedures.

[0206] In this method, information regarding the use of time / frequency resources (repetition interval, Time / Frequency Resource Mapping, etc.) in repeated transmission can be considered to be standardized or transmitted via separate signaling. For example, when Inter-Slot Repetition is applied, the terminal can expect to receive PDCCH CSS in a number of available slots equal to the number of repeated transmissions, which is 2 slots, including at least the first slot that received the PDCCH CSS.

[0207] [Proposal 1-4: SIB Based Explicit Indication]

[0208] Figure 18 is a diagram illustrating an example of an SIB-based explicit instruction process.

[0209] Proposal 1-4 proposes a method in which the repetition status is explicitly indicated by including it in SIB1 or SIB19 (i.e., the PDSCH related to SIB11 or the PDSCH related to SIB19), as shown in FIG. 18. In this case, the information can be transmitted using the bits of each SIB, and the information corresponding to the Bit 0 / Bit 1 mapping on a 1-bit basis can be defined according to standard specifications. (e.g., Bit 0 – Disabled / Bit 1 – Enabled, Bit 0 – Enabled, Bit 1 – Disabled)

[0210] If a Repetition Factor greater than 2 is supported for the repeated transmission of PDCCH CSS through the standard specification, instead of using 1 bit to indicate Repetition Disabled / Enabled, 2 Repetition Factors may be indicated, whereby the Repetition Factor corresponding to the Bit 0 / Bit 1 Mapping may be defined according to the standard specification. (e.g., Bit 0 - No Repetition / Bit 1 – Repetition Factor 2, Bit 0 - No Repetition / Bit 1 – Repetition Factor 4) Alternatively, 2 bits may be used to indicate the Repetition Factor. (e.g., Bit 00 – No Repetition / Bit 01 – Repetition Factor 2 / Bit 10 – Repetition Factor 4 / Bit 11 – Repetition Factor 8) or, the Repetition Factor may be transmitted via SIB1 or SIB19 and Repetition Enabled / Disabled may be transmitted separately for individual or multiple PDCCH CSS Types, in which case each terminal may determine whether each PDCCH CSS Type is being transmitted repeatedly through a separate message, and if Repetition is applied, apply the Repetition Factor determined via SIB1 or SIB19. Or, Repetition Enabled / Disabled may be transmitted via SIB1 or SIB19 and the Repetition Factor may be transmitted or defined and used separately for individual or multiple PDCCH CSS Types, in which case each terminal may determine whether each PDCCH CSS Type is being transmitted repeatedly via SIB1 or SIB19 and then determine and apply the Repetition Factor to be applied at that time.Alternatively, Repetition Enabled / Disabled and Repetition Factor may be defined as separate fields and transmitted either entirely through SIB1 or entirely through SIB19, or Repetition Enabled / Disabled and Repetition Factor may be defined separately in SIB1 and SIB19 and transmitted to each other.

[0211] If an Explicit Indication of whether to repeat transmission is performed via SIB1, the relevant information may be applied to PDCCH CSS Types that must be received after the delivery / reception of SIB1. Accordingly, the recurring transmission of Type0A PDCCH CSS may be indicated by an Explicit Indication via SIB1, or the recurring transmission of Type1 PDCCH CSS may be indicated by an Explicit Indication via SIB1, or the recurring transmission of Type2 PDCCH CSS may be indicated by an Explicit Indication via SIB1, or the recurring transmission of Type0A / 1 PDCCH CSS may be indicated at once by an Explicit Indication via SIB1, or the recurring transmission of Type0A / 2 PDCCH CSS may be indicated at once by an Explicit Indication via SIB1, or the recurring transmission of Type1 / 2 PDCCH CSS may be indicated at once by an Explicit Indication via SIB1, or the recurring transmission of Type0A / 1 / 2 PDCCH CSS may be indicated at once by an Explicit Indication via SIB1. Whether which PDCCH CSS Type(s) among the PDCCH CSS Types transmitted after the delivery of SIB1 containing PDCCH CSS iteration transmission information performs iteration transmission based on said information can be defined by the standard specification.

[0212] If an explicit indication regarding recurrence is provided via SIB1, such information may be applied to the PDCCH CSS Types that must be received after the delivery / reception of SIB19. Therefore, the recurrence of Type 1 PDCCH CSS may be indicated by the explicit indication via SIB19, or the recurrence of Type 2 PDCCH CSS may be indicated by the explicit indication via SIB19, or the recurrence of Type 1 and Type 2 PDCCH CSS may be indicated simultaneously by the explicit indication via SIB19. In this way, which PDCCH CSS Type(s) among the PDCCH CSS Types transmitted after the delivery of SIB19 containing PDCCH CSS recurrence information perform recurrence based on that information may be defined by the standard specification.

[0213] In this case, if repeated transmission for multiple types of PDCCHCSS is supported through a single specific SIB, the repeated transmission status for a specific type of PDCCH CSS can be defined in a single field (a single specific bit), and the repeated transmission status for the remaining PDCCH CSS types can be defined in the same way. For example, when using SIB1, the repeated transmission status for Type0A PDDCH CSS can be defined, and the repeated transmission status for Type1 / 2 PDCCH CSS can be defined in the same way. As another example, when using SIB19, the repeated transmission status for Type1 PDDCH CSS can be defined, and the repeated transmission status for Type2 PDCCH CSS can be defined in the same way. In other words, the repeated transmission status for multiple types of PDCCH CSS can be indicated through the same bit field. Alternatively, if repeated transmission for multiple PDCCH CSS types is supported through a single specific SIB, a separate bit (field) can be applied to each PDDCH CSS type to indicate the repeated transmission status for each separately. Alternatively, it is possible to support repeated transmission for multiple PDCCH CSS types through multiple SIBs. For example, SIB1 can be used to indicate whether to repeat transmission for Type0A PDCCH CSS, and SIB19 can be used to indicate whether to repeat transmission for Type1 / 2 PDCCH CSS.

[0214] In this case, if the repetitive transmission status for multiple types of PDCCH CSS is supported using the same field, the mapping for the repetitive transmission status of each PDCCH CSS type may be defined differently for the same bit value. For example, when using SIB1, Repetition Enabled / Disabled is indicated by the same bit field for Types 0A, 1, and 2, and the interpretation of Enabled / Disabled for bits 0 and 1 may be determined differently depending on each type. As another example, Repetition Enabled / Disabled is indicated by the same bit field for Types 1 and 2, and the interpretation of Enabled / Disabled for bits 0 and 1 may be determined differently depending on each type. The definition of such mapping may be determined by standard specifications.

[0215] The terminal receives the SIB, obtains whether to repeat transmission, and then proceeds with the reception process by assuming that repeated transmission is in progress according to the instructions for the PDCCH CSS Type(s) defined as applying the instructions according to standard specifications. The terminal may proceed with subsequent procedures accordingly, depending on whether decoding is successful or unsuccessful during the reception process.

[0216] In this method, information regarding the use of time / frequency resources (repetition interval, time / frequency resource mapping, etc.) in repeated transmissions can be considered to be standardized or transmitted via separate signaling. For example, when Inter-Slot Repetition is applied, the terminal can expect to receive PDCCH CSS in a number of available slots equal to the number of repeated transmissions, which is 2 slots, including at least the first slot that received the PDCCH CSS.

[0217] [Proposal 1-5: Signaling Omission UE Blind Decoding]

[0218] FIG. 19 is a diagram illustrating an example of a process for performing UE blind decoding without signaling.

[0219] Proposal 1-5 proposes a signaling omission UE blind decoding method in which repeated transmission and the reception process proceed without a separate indication regarding whether repeated transmission is possible, as shown in FIG. 19. The base station performs repeated transmission without a separate indication for the PDCCH CSS Type to which signaling omission UE blind decoding is applied, and the terminal proceeds with reception operations and related procedures in preparation for repeated transmission of the PDCCH CSS Type under the assumption that repeated transmission is possible without receiving prior notification from the base station / network regarding whether repeated transmission is possible. This signaling omission UE blind decoding can be applied regardless of the PDCCH CSS Type. That is, Proposal 1-5 can be used for repeated transmission of Type0 / Type0A / Type1 / Type2 PDCCH CSS.

[0220] For the operation of Proposal 1-5, the terminal requires the setting of a repeat transmission interval for receiving repeat transmissions. The repeat transmission interval of Proposal 1-5 is intended to define an interval where PDCCH CSS repeat transmissions may exist, and the terminal performs operations to receive signaling omission UE blind decoding only for the received signals located within the corresponding repeat transmission interval. This repeat transmission interval may be determined as the interval between the first and second transmissions in the repeat transmission, the interval between repetitions, or a multiple of the SSB (Synchronization Signal Block) Periodicity and SSB Periodicity, or a multiple of the Slot, or a multiple of the Frame. This repeat transmission interval may be predetermined through standard specifications or indicated to the terminal through Cell-Specific Signaling such as MIB. For example, through standard specifications, a repeat transmission interval can be defined as the slot in which the first PDCCH CSS was transmitted and the next slot; or a number of slots corresponding to the Repetition Factor starting from the slot in which the first PDCCH CSS was transmitted; or the slot in which the first PDCCH CSS was transmitted and a slot located a specific number of slots away from it; or the symbols in which the first PDCCH CSS is located within the slot in which the first PDCCH CSS was transmitted and consecutive symbols of the same symbol length excluding them. In this case, if UE blind decoding with signal omission for multiple PDCCH CSS types is supported, the repeat transmission intervals for individual PDCCH CSS types can be defined identically or separately from each other.

[0221] The terminal may perform the following reception operations for the signaling omission UE blind decoding of Proposal 1-5. For example, the terminal may first perform reception and decoding based on Blind Decoding for the PDCCH CSS Type for time / frequency resources where the pre-instructed PDCCH CSS Type may be located, without assuming repetitive transmission. If the PDCCH is not detected during this Blind Decoding process, the terminal may assume that repetitive transmission has been performed and perform reception and decoding based on Blind Decoding through Soft Combining for all combinations of resources for the first and second transmissions capable of repetitive transmission, within the time / frequency resources where the first and second transmissions may be located. If the PDCCH is not detected even through this process, the terminal may assume that the PDCCH was not received normally and proceed to the next procedure following the decoding failure. If decoding is successful, the terminal may assume that the PDCCH was received normally and proceed to the next procedure.

[0222] Alternatively, the terminal may perform the following receiving operations for the signaling omission UE blind decoding of Proposal 1-5. For example, the terminal may sequentially or in parallel perform PDCCH Blind Decoding in the time and frequency resources where the first transmission may be located, without first assuming repetitive transmission, PDCCH Blind Decoding in the time and frequency resources where the second transmission may be located, and PDCCH Blind Decoding through Soft Combining for all combinations of resources between the first and second transmissions capable of repetitive transmission. If the PDCCH is not detected in any of these cases, the terminal may assume that the PDCCH was not received normally and proceed to the next procedure following the decoding failure. If a case of successful decoding occurs, the terminal may assume that the PDCCH was received normally, terminate the remaining parallel processes, and proceed to the next procedure following the decoding success.

[0223] During these processes, depending on its capabilities, the terminal can infer that PDCCH CSS transmission was not performed on a specific time resource (e.g., slot / symbol) among the candidate time resources where the repeated transmission signal (i.e., the second transmission) can be delivered within the repeated transmission interval, through processes such as Correlation, Noise Estimation in Soft Combining signals, or Blind Decoding. In this case, the terminal can proceed with the receive / decode process by considering only the remaining time resources, excluding those in question, within the repeated transmission interval.

[0224] For the purposes of Proposal 1-5, the terminal must be able to perform the receiving operation defined above or the corresponding receiving operation of signaling omission UE blind decoding when there is no indication of whether to perform repeated transmission, and this can be additionally defined as a Capability and reported in the Capability Report. The Capability may be additionally defined by PDCCH Type or by detailed functions (capability to perform signaling omission UE blind decoding, possibility of parallel execution, assumption of non-performance of PDCCH Repetition, etc.), and can be reported in the Capability Report based on this. Furthermore, if the repeated transmission interval for signaling omission UE blind decoding is defined in relation to SSB Periodicity, the terminal needs to estimate the SSB Periodicity, and this can be defined as a Capability and reported in the Capability Report.

[0225] In this method, information regarding the use of time / frequency resources (repetition interval, time / frequency resource mapping, etc.) in the repetition can be considered to be standardized or transmitted via separate signaling. For example, the terminal can expect to receive PDCCH CSS in a number of available slots corresponding to the configured repeat transmission interval, including at least the first slot that received the corresponding PDCCH CSS Type.

[0226] [Proposal 2: Repetition Method of PDCCH]

[0227] Proposal 2 proposes iterative transmission methods for PDCCH CSS. Specifically, the detailed method of Proposal 2 determines the location of the time resource where the second transmission exists during the iterative transmission of PDCCH CSS and the iterative transmission interval. The iterative transmission methods below may be applied simultaneously or separately depending on each Type. For example, the slot interval method of Proposal 2-1 may be applied for the iterative transmission of Type 0 PDCCH CSS, and the symbol interval method of Proposal 2-2 may be applied for the iterative transmission of Type 0A / Type 1 / Type 2 PDCCH CSS.

[0228] In Proposal 2, it is assumed that the first and second transmissions of the PDCCH CSS Type, which are directed to repeated transmission, have the same AL (Aggregation level), the number of coded bits, and the same candidate index. Additionally, it is assumed that the first and second transmissions have the same CSS size (number of symbols on the time axis and number of RBs on the frequency axis) in the time and frequency axes.

[0229] [Proposal 2-1: Slot Interval Based Repetition]

[0230] Figure 20 is a diagram illustrating an example of slot-interval-based iterative transmission.

[0231] Proposal 2-1 proposes a slot interval method as shown in Fig. 21. This is a method in which the interval between the first and second transmissions of a repeatable transmission is determined in slot units according to standard specifications. In this case, when a terminal wants to confirm a repeatable transmission or take related actions, it can check the time interval of each repetition in the repeatable transmission, i.e., the slot interval, without separate signaling overhead or through signaling. For example, in the repeatable transmission of Type0 PDCCH CSS, the value of the interval X can be normalized to 1, and in this case, the terminal can expect the repeatable transmission of Type0 PDCCH CSS to proceed in two consecutive slots based on this. As another example, in the repeatable transmission of Type0 PDCCH CSS, the value of the interval X can be normalized to a positive integer, and in this case, the terminal can expect the repeatable transmission of Type0 PDCCH CSS in the slot where the first transmission was performed and in a slot located X units away from it based on this.

[0232] If the Repetition Factor exceeds 2, the terminal may set the intervals between all transmissions for the repetitive transmission, such as the interval between the second and third transmissions and the interval between the third and fourth transmissions, to be equal to the slot interval X between the first and second transmissions. In this case, the position of the starting symbol of each slot of all transmissions in the repetitive transmission may be set to be the same as the first transmission.

[0233] In this proposal 2-1, the slot interval X can be determined separately according to parameters for the PDCCH CSS Type or Search Space. For example, a separate slot interval X can be provided for each PDCCH CSS Type. In addition, for repeated transmissions for Type 0 PDCCH CSS, the slot interval X can be determined according to M defined in Tables 13-11, 13-12, and 13-12A of 38.213. For example, considering that the number of SSB indices in FR1 is 4, X can be defined as 2 when M=1 / 2, X can be defined as 4 when M=1, and X can be defined as 1 when M=2.

[0234] If the slot interval of Proposal 2-1 is determined by the specification to be used for the repeated transmission of PDCCH CSS of a specific Type and parameter, the specific slot interval value X may be defined commonly through the system specification or separately according to each Type / Parameter, etc., so that the terminal can identify the interval without a separate indication of the interval, or it may be indicated through RRC messages such as PDCCH-ConfigCommon that indicate parameters for the PDCCH CSS of the corresponding Type, or through signaling such as PDCCH / SIB1 / SIB19 regarding a separate MIB / SIB1, so that the terminal applies the indicated interval, or it may apply an interval implicitly given by other parameters that are predefined or configured, or only whether the slot interval is used is determined by the specification, and the terminal can blindly search for the specific interval value X. These operations may be performed separately according to each CSS Type and parameter, etc.

[0235] When using slot intervals via indication, the slot interval X for a previously repeated PDCCH CSS Type can be used as the slot interval for another Type of PDCCH CSS to be repeated later. For example, after X for the repeated transmission of Type0 PDCCH CSS is indicated, the interval for the repeated transmission of Type0A / Type1 / Type2 PDCCH CSS can be applied as is without a separate indication.

[0236] When using slot intervals via indication, the K0 of the DCI corresponding to the immediately preceding repeated PDCCH CSS Type (the number of slots between PDCCH / DCI and PDSCH transmissions) can be used as the slot interval for the PDCCH CSS Type to be repeatedly transmitted later.

[0237] When only the use of the slot interval is determined and the terminal blindly searches for a specific interval value X, possible candidate groups or maximum values ​​of X may be transmitted via signaling or determined through specifications.

[0238] If the slot interval X of Proposal 2-1 is configured to 0 or given, this method can be interpreted as an Intra-Slot Repetition method. In this case, the second transmission of the repetitive transmission is located in the same slot as the first transmission, and therefore the symbol position(s) within the slot where the first and second transmissions exist can be determined differently. At this time, the symbol position of the second transmission can be determined by the methods presented in Proposal 2-2.

[0239] Meanwhile, if the slot interval X of Proposal 2-1 is configured or given as a positive number greater than 0, this method can be interpreted as an Inter-Slot Repetition method. In this case, the symbol position(s) within each Slot where the first transmission and the second transmission exist can be determined identically.

[0240] For a PDCCH CSS Type that undergoes repeated transmission, the interval with the corresponding PDSCH transmission can be determined based on the slot where the first transmission of the PDCCH CSS repeated transmission took place, or based on the slot where the second transmission of the PDCCH repetition took place.

[0241] For a PDCCH CSS Type where Repetition has been confirmed (e.g., Indication of Repetition Enabled), if the terminal identifies the slot interval X or the rule for calculating it through specification definitions or indications, it may anticipate Repetition for a slot X slots away from the slot where the first transmission occurred and proceed with the reception process. Alternatively, if the slot interval X is unknown, the terminal may proceed with a Blind Decoding-based reception process to find Repetition, targeting slots up to a predetermined maximum interval from the slot where the first transmission occurred, or a group of candidate slots where a second transmission is possible. The terminal may proceed with subsequent procedures accordingly, depending on whether decoding is successful or unsuccessful during the reception process.

[0242] [Proposal 2-2: Symbol Interval Based Repetition]

[0243] Figure 21 is a diagram illustrating an example of a symbol interval-based iterative transmission.

[0244] Proposal 2-2 proposes a symbol interval method as shown in Fig. 21. This is a method in which the interval between the first and second transmissions of a repeating transmission is determined in units of symbols according to standard specifications. In this case, when a terminal wants to confirm a repeating transmission or take related actions, it can check the time interval, i.e., the symbol interval, of each repeat in the repeating transmission without separate signaling overhead or through signaling. For example, when the starting symbol offset value of the first transmission of the PDCCH CSS in a slot is f (i.e., the first transmission starts from the f-th symbol among symbols 0 to 13 of the slot), the value of the interval X in a specific type of PDCCH CSS repeating transmission can be standardized to f+7, and in this case, the terminal can expect the first transmission from the f-th symbol and the second transmission from the (f+7)-th symbol during the repeating transmission of the PDCCH CSS of that type based on this. As another example, in the repeated transmission of Type 0 PDCCH CSS, the value of the interval X can be normalized to a positive integer. In this case, the terminal can expect the repeated transmission of the corresponding Type PDCCH CSS with the (f+X) symbol, which is X away from the f-th symbol in the slot where the first transmission was performed, as the starting symbol of the second transmission. However, if the calculated symbol interval where the second transmission exists extends beyond the slot where the first transmission exists (e.g., f+X > 13 based on the placement of symbols 0 to 13 in the slot), the terminal may not expect repeated reception in the slot where the first transmission exists, and in this case, the terminal can expect reception of the second transmission from the same symbol starting position (f) in the next continuous slot where X = 14.

[0245] In this proposal 2-2, the symbol interval X can be determined separately according to parameters for the PDCCH CSS Type or Search Space. For example, a separate interval X can be provided for each PDCCH CSS Type. Alternatively, multiple Xs can be provided based on the starting symbol offset value f of the first transmission of the PDCCH iterative transmission. For example, when there are two candidates for applicable X, X1 and X2, defined by a specific Type and f, the symbol interval containing the second transmission calculated by the values ​​of f and X1 extends beyond the slot containing the first transmission (e.g., based on placing symbols 0 to 13 in the slot, f+X1 > 13), and the symbol interval containing the second transmission calculated by the values ​​of f and X2 is located within the slot containing the first transmission, the starting position of the symbol interval containing the second transmission can be determined as f+X2. In this case, if a single X is defined, and the symbol interval where the second transmission exists extends beyond the slot where the first transmission exists, X is changed to 14 so that the second transmission can be performed starting from symbol f of the next slot. Alternatively, a separate interval X can be used depending on the starting symbol offset value f of the first transmission of the PDCCH iterative transmission and the symbol length y of the first transmission. For example, depending on the starting symbol offset value f of the first transmission of the PDCCH iterative transmission and the symbol length y of the first transmission, X is set to y so that the second transmission can proceed starting from symbol (f+y). In this case as well, if the symbol interval where the second transmission exists extends beyond the slot where the first transmission exists (e.g., first symbol position f+y > 13, last symbol position f+y+y-1 > 13), X is changed to 14 instead of y so that the second transmission can be performed starting from symbol f of the next slot.

[0246] If the Repetition Factor exceeds 2, the terminal may set the intervals between all transmissions for repeated transmissions—such as the interval between the second and third transmissions, and the interval between the third and fourth transmissions—to be equal to the symbol interval X between the first and second transmissions. In this case, if the symbol position where a specific R-th transmission exists extends beyond the slot where the previous (R-1)-th transmission exists, the R-th transmission may start from the slot following the slot where the (R-1)-th transmission exists. In this case, the starting symbol position may be set to be the same as the starting symbol position in the corresponding slot of the first transmission, or the same as the starting symbol position in the corresponding slot of the (R-1)-th transmission, or the same as the starting symbol position of the transmission determined or instructed among the first through (R-1) transmissions.

[0247] If the use of the symbol interval proposed in Proposal 2-2 is determined by the standard to be used for the repeated transmission of PDCCH CSS of a specific Type and parameter, the specific symbol interval value X may be defined commonly through the system standard or separately according to each Type / Parameter, etc., so that the terminal can identify the interval without a separate indication of the interval, or it may be indicated through an RRC message such as PDCCH-ConfigCommon that indicates the parameters for the PDCCH of the corresponding Type, or through signaling such as PDCCH / SIB1 / SIB19 regarding a separate MIB / SIB1, so that the terminal applies the indicated interval, or it may apply an interval implicitly given by other parameters that are predefined or configured, or only whether the interval is used is determined by the standard, and the terminal may blindly search for the specific interval value X. These operations may be performed separately according to each PDCCH Type and parameter, etc.

[0248] When using symbol spacing via indication, the symbol spacing X for a previously repeated PDCCH CSS Type can be used as the fixed slot spacing for a subsequent repeated PDCCH Type. For example, after X is indicated for the repeated transmission of Type0A PDCCH CSS, the spacing for the repeated transmission of Type1 / Type2 PDCCH CSS can be applied as is without a separate indication.

[0249] When using symbol spacing via indication, the symbol offset f for the search space of the first transmission of the current PDDCH CSS Type (i.e., the starting position of the symbol in the slot of the first transmission) can be used to define the symbol position within the slot of the second transmission. For example, when a slot consists of a total of 14 symbols from the 0th symbol to the 13th symbol, (f+7) can be used as the starting position of the symbol for the second transmission, or (13 –f) can be used as the ending position of the symbol for the second transmission.

[0250] When only the use of the symbol interval is determined and the terminal blindly searches for a specific interval value X, possible candidate sets or maximum values ​​of X may be transmitted via signaling or determined through specifications. Alternatively, the remaining symbols in the corresponding slot located after the symbols where the first transmission is located may be determined as candidate sets for the symbols where the second transmission is located.

[0251] If the CSS of the second transmission according to the symbol spacing X of Proposal 2-2 is located in the same slot as the CSS of the first transmission, it can be interpreted as an Intra-Slot Repetition method.

[0252] For a PDCCH CSS Type undergoing repeated transmission, the interval with the corresponding PDSCH transmission may be determined based on the slot where the first transmission of the PDCCH CSS repeated transmission took place, or based on the slot where the second transmission of the PDCCH CSS repeated transmission took place. If the second transmitted CSS is located in the same slot as the first transmitted CSS (i.e., intra-slot repetition), the slot interval with the corresponding PDSCH transmission is the same for both of the above cases.

[0253] For a PDCCH CSS Type where Repetition has been confirmed (e.g., Indication of Repetition Enabled), if the terminal identifies the interval X or the rule for calculating the interval through specification definitions or indications, it can calculate the symbol locations where the second transmission will occur from the symbol locations of the slot where the first transmission took place, anticipate the repeated transmission (second transmission) at those symbol locations, and proceed with the reception process. Alternatively, if the symbol interval or the rule for calculating the interval is unknown, the terminal can proceed with a Blind Decoding-based reception process to find Repetition by assuming the second transmission at the remaining symbol locations, excluding the symbol locations where the CSS of the first transmission exists. In this case, the candidate groups where the actual second transmission is possible at the remaining symbol locations may be separately indicated, or rules or patterns for the candidate groups may be defined in the specifications within the Type / Parameters of the PDCCH CSS; in this case, the terminal can proceed with a Blind Decoding-based reception process to find Repetition by considering only those candidate groups. The terminal can proceed with subsequent procedures accordingly, depending on whether decoding is successful or unsuccessful during the reception process.

[0254] [Proposal 2-3: SSB Index Based Repetition]

[0255] Figure 22 is a diagram illustrating an example of an iterative transmission based on an SSB index.

[0256] Proposal 2-3 proposes an SSB Index-based method as shown in Fig. 22. This method can be applied to the repetitive transmission of Type0 PDCCH CSS, in which the first and second transmissions of the repetitive transmission correspond to separate SSB Indices according to standard specifications. In this case, when a terminal wants to check the repetitive transmission or take related actions, it can check the SSB Indices corresponding to the first and second transmissions in the Type0 PDCCH repetitive transmission without separate signaling overhead or through signaling. For example, SSB Index1 may be the first transmission and SSB Index2 may be the second transmission, or SSB Index1 may be the first transmission and SSB Index3 may be the second transmission, or SSB Index1 may be the first transmission and SSB Index4 may be the second transmission, or SSB Index2 may be the first transmission and SSB Index3 may be the second transmission, or SSB Index2 may be the first transmission and SSB Index4 may be the second transmission, or SSB Index3 may be the first transmission and SSB Index4 may be the second transmission, and the terminal may proceed with a reception procedure related to repeated transmission based on this.

[0257] In these proposals 2-3, the connections between each SSB (i.e., whether any two SSBs are defined as repeating each other) may be determined separately according to parameters, etc. For example, these connections may be defined differently depending on the number of SSBs included in the SSB Burst Set or M defined in Tables 13-11, 13-12, and 13-12A of 38.213.

[0258] In cases where the use of connections between SSB Indices in Proposal 2-3 of the specification is determined for the repeated transmission of Type0 PDCCH CSS of specific parameters, the specific connection relationship may be defined commonly through the system specification or separately according to each parameter such as M, so that the terminal can identify the interval without a separate indication of the interval, or the terminal may apply the indicated connection relationship through signaling such as RRC messages such as PDCCH-ConfigCommon or separate MIBs indicating parameters for Type0 PDCCH CSS, or apply an interval implicitly given by other parameters that are predefined or configured, or the terminal may blindly search for the specific connection relationship while only the use of the SSB Index-based method is determined by the specification. These operations may be performed separately according to each parameter for Type0 PDCCH CSS.

[0259] When only the use of an SSB Index connection relationship is determined and the terminal blindly searches for specific SSB Index connection relationships, a group of possible connection relationship candidates may be transmitted via signaling or determined through specifications.

[0260] For a Type 0 PDCCH CSS in which repetition has been confirmed (e.g., Indication of Repetition Enabled), if the terminal confirms the specific SSB Index connection relationship (whether two SSB Indexes are in a repeat transmission relationship) through specification definitions or indications, it may anticipate the repetition of the PDCCH CSS for the SSB Index that was transmitted first and the PDCCH CSS for the SSB Index that was transmitted second, and proceed with the reception process. Alternatively, if the specific SSB Index connection relationship is unknown (e.g., repeat transmission has been confirmed but it is unknown which two SSB Indexes are in a repeat relationship), the terminal may proceed with a reception process based on Blind Decoding to find repetition by targeting a candidate group of possible combinations of SSB Index connection relationships. In this case, the connection relationships and candidate groups capable of actual repeat transmission may be separately indicated, or rules or patterns regarding the candidate groups may be defined in the specifications within the parameters of the Type 0 PDCCH CSS; in this case, the terminal may proceed with the Blind Decoding process to find repetition by considering only those candidate groups. The terminal can proceed with subsequent procedures accordingly, depending on whether decoding is successful or unsuccessful during the reception process.

[0261] In a CSS for two SSB indices where repetitive transmission is performed, the relative frequency (RB) and time (symbol) positions within the first and second transmissions within their respective CSSs may be determined identically, or their respective relative frequency / time positional relationships may be predetermined. This can be predefined through standardization or communicated from the base station to the terminal via indication through signaling. In this case, the terminal may have the same number of seeks as during non-repetitive transmission when performing blind decoding for repetitive transmission. For example, if the number of seeks to attempt blind decoding (i.e., the number of PDCCH candidates that can be located within the CSS) when considering non-repetitive transmission in a single CSS is 'a', then the total number of possible candidate combinations in the first and second transmissions is also 'a', since their relative positional relationships are predetermined. Meanwhile, in a CSS for two SSB indices where repetitive transmission is performed, the relative frequency (RB) and time (symbol) positions within the respective CSSs for the first and second transmissions may not be determined through standardization or known to the terminal. In this case, when the terminal performs Blind Decoding for repetitive transmission, it can search all combinations of Blind Decoding for each SSB index, resulting in a number of searches equivalent to the square of the number of searches compared to non-repetitive transmission. For example, if the number of searches to attempt Blind Decoding (i.e., the number of PDCCH candidates that can be located within the CSS) when considering non-repetitive transmission in a single CSS is 'a', then the possible combinations of candidates for the first and second transmissions are a * a = a 2 It becomes.

[0262] FIG. 23 is a flowchart illustrating a method in which a terminal performs communication according to one embodiment.

[0263] The operations disclosed in the flowchart of FIG. 23 may be performed in combination with various embodiments of the present disclosure. In one example, the operations disclosed in the flowchart of FIG. 23 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. 23 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. 23 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. 23 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.

[0264] In step S2301, a terminal according to one embodiment may receive a first iteration of a Physical Downlink Control Channel (PDCCH) from a base station communicating with the terminal via a Non-Terrestrial Network (NTN). In other words, the terminal may receive a first iteration of the PDCCH iterations from the base station.

[0265] In step S2302, a terminal according to one embodiment can receive a second iterative transmission of the PDCCH from the base station.

[0266] In one embodiment, even after the second iterative transmission, the terminal can receive at least one more iterative transmission from the base station.

[0267] In step S2303, a terminal according to one embodiment can receive a PDSCH (Physical Downlink Shared Channel) associated with the PDCCH from the base station.

[0268] In one embodiment, the first iterative transmission and the second iterative transmission of the PDCCH may be received through consecutive slots or consecutive sets of symbols.

[0269] In one embodiment, the first iterative transmission and the second iterative transmission of the PDCCH can be received through the consecutive slots.

[0270] In one embodiment, the PDCCH may represent a Type 0 CSS (Common Search Space) related PDCCH.

[0271] According to one embodiment, the terminal can receive a Physical Broadcast Channel (PBCH) from the base station. Whether to perform repeated transmission of the PDCCH can be indicated through the payload of the PBCH.

[0272] In one embodiment, the first repetitive transmission of the PDCCH is received by the terminal through a first slot, and the second repetitive transmission of the PDCCH is received by the terminal through a second slot adjacent to the first slot, and the interval between the first slot and the second slot is determined based on a time scaling factor, and the first slot and the second slot may be adjacent based on the time scaling factor being 2, 1, or 1 / 2.

[0273] In one example, the time scaling factor can be denoted as M.

[0274] In one embodiment, the PDCCH may indicate at least one of the time resources or frequency resources of the PDSCH including SIB (System Information Block) 1.

[0275] In one embodiment, in the first slot, blind decoding for the first iterative transmission of the PDCCH may be performed, and in the second slot, blind decoding for the second iterative transmission of the PDCCH may be performed.

[0276] In one embodiment, the first iterative transmission and the second iterative transmission of the PDCCH are received through the consecutive sets of symbols, and the consecutive sets of symbols may include a first set of symbols including at least one first symbol and a second set of symbols including at least one second symbol.

[0277] In one embodiment, the last symbol of the first symbol set may be adjacent to the first symbol of the second symbol set.

[0278] In one embodiment, the PDCCH may represent a PDCCH associated with at least one of Type 0A CSS, Type 1 CSS, or Type 2 CSS.

[0279] In one embodiment, at least one blind decoding may be performed for at least one of the first iterative transmission of the PDCCH or the second iterative transmission of the PDCCH in at least one of the first symbol set or the second symbol set.

[0280] In one embodiment, the at least one blind decoding may be performed once or twice.

[0281] According to one embodiment, the terminal can transmit capability information of the terminal to the base station. The number of times at least one blind decoding is performed can be determined based on the capability information of the terminal.

[0282] FIG. 24 is a flowchart illustrating a method in which a base station performs communication according to one embodiment.

[0283] The operations disclosed in the flowchart of FIG. 24 may be performed in combination with various embodiments of the present disclosure. In one example, the operations disclosed in the flowchart of FIG. 24 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. 24 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. 24 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. 24 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.

[0284] In step S2401, a base station according to one embodiment can transmit a first iteration of PDCCH to a terminal communicating with the base station via NTN.

[0285] In step S2402, a base station according to one embodiment can transmit a second iterative transmission of the PDCCH to the terminal.

[0286] In step S2403, a base station according to one embodiment can transmit a PDSCH associated with the PDCCH to the terminal.

[0287] In one embodiment, the first iterative transmission and the second iterative transmission of the PDCCH may be transmitted through consecutive slots or consecutive sets of symbols.

[0288] 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.

[0289] 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.

[0290] 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 most important method steps may be performed by such a device.

[0291] 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.

[0292] 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 receiving a first repeated transmission of a PDCCH (Physical Downlink Control Channel) from a base station communicating with the terminal via an NTN (Non-Terrestrial Network); A step of receiving a second iterative transmission of the PDCCH from the base station; and The method includes the step of receiving a PDSCH (Physical Downlink Shared Channel) associated with the PDCCH from the base station, A method in which the first iterative transmission and the second iterative transmission of the above PDCCH are received through consecutive slots or consecutive sets of symbols.

2. In Paragraph 1, The first iterative transmission and the second iterative transmission of the above PDCCH are received through the consecutive slots.

3. In Paragraph 2, The above PDCCH is a method representing a Type 0 CSS (Common Search Space) related PDCCH.

4. In Paragraph 2, The method further includes the step of receiving a Physical Broadcast Channel (PBCH) from the base station, A method in which whether to perform repeated transmission of the above PDCCH is indicated through the payload of the above PBCH.

5. In Paragraph 2, The first iterative transmission of the above PDCCH is received by the terminal through the first slot, and The second iterative transmission of the above PDCCH is received by the terminal through the second slot adjacent to the first slot, and The interval between the first slot and the second slot is determined based on a time scaling factor, and A method in which the first slot and the second slot are adjacent, based on the above time scaling factor being 2, 1, or 1 / 2.

6. In Paragraph 2, A method in which the above PDCCH indicates at least one of the time resources or frequency resources of the above PDSCH, including SIB (System Information Block) 1.

7. In Paragraph 2, In the first slot above, blind decoding for the first iterative transmission of the PDCCH is performed, and A method in which blind decoding for the second iterative transmission of the PDCCH is performed in the second slot.

8. In Paragraph 1, The first iterative transmission and the second iterative transmission of the above PDCCH are received through the consecutive sets of symbols, and A method in which the above consecutive sets of symbols include a first set of symbols including at least one first symbol and a second set of symbols including at least one second symbol.

9. In Paragraph 8, A method in which the last symbol of the first symbol set is adjacent to the first symbol of the second symbol set.

10. In Paragraph 8, The above PDCCH is a method representing a PDCCH associated with at least one of type 0A CSS, type 1 CSS, or type 2 CSS.

11. In Paragraph 8, A method in which at least one blind decoding is performed for at least one of the first iterative transmission of the PDCCH or the second iterative transmission of the PDCCH in at least one of the first symbol set or the second symbol set.

12. In Paragraph 11, A method in which at least one blind decoding is performed once or twice.

13. In Paragraph 12, The method further includes the step of transmitting capability information of the above terminal to the above base station, A method in which the number of times at least one blind decoding is performed is determined based on the capability information of the terminal.

14. 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 receiving a first iterative transmission of PDCCH from a base station communicating with the terminal via NTN; A step of receiving a second iterative transmission of the PDCCH from the base station; and The method includes the step of receiving a PDSCH associated with the PDCCH from the base station, The first iterative transmission and the second iterative transmission of the above PDCCH are received through consecutive slots or consecutive sets of symbols, terminal.

15. In a base station performing communication in a wireless communication system, At least one transmitter / receiver; At least one processor; and It includes at least one memory connected to the above-mentioned at least one processor to enable operation, and storing commands that control the base station to perform operations when executed by the processor, The above operations are, A step of transmitting a first iterative transmission of PDCCH to a terminal communicating with the base station via NTN; A step of transmitting a second iterative transmission of the PDCCH to the terminal; and The method includes the step of transmitting a PDSCH associated with the PDCCH to the terminal, The first iterative transmission and the second iterative transmission of the above PDCCH are base stations transmitted through consecutive slots or consecutive sets of symbols.

Images