Method for performing communication in wireless communication system and device therefor

Abstract

A device according to various embodiments may: receive configuration information about a first transmission path and a second transmission path; receive a first PDSCH through the first transmission path; transmit first HARQ ACK information about the first PDSCH; receive a second PDSCH through the second transmission path; and determine whether data corresponding to the first PDSCH is included in the second PDSCH on the basis that (i) the second PDSCH is received after the transmission of the first HARQ ACK, and (ii) the second transmission path is related to a non-terrestrial network (NTN).

Description

Method for performing communication in a wireless communication system and device for the same

[0001] This invention relates to a method for transmitting and receiving signals between a terminal and a base station in a wireless communication system and an apparatus for doing so.

[0002] A wireless communication system is a multiple access system that supports communication with multiple users by sharing available system resources (e.g., bandwidth, transmission power, etc.). Examples of multiple access systems include CDMA (code division multiple access), FDMA (frequency division multiple access), TDMA (time division multiple access), OFDMA (orthogonal frequency division multiple access), SC-FDMA (single carrier frequency division multiple access), and MC-FDMA (multi carrier frequency division multiple access) systems.

[0003] Sidelink (SL) refers to a communication method in which User Equipment (UE) establishes a direct link to directly exchange voice or data between terminals without passing through a Base Station (BS). SL is being considered as a solution to address the burden on base stations caused by rapidly increasing data traffic.

[0004] V2X (vehicle-to-everything) refers to a communication technology that exchanges information with other vehicles, pedestrians, and infrastructure-equipped objects through wired or wireless communication. V2X can be classified into four types: V2V (vehicle-to-vehicle), V2I (vehicle-to-infrastructure), V2N (vehicle-to-network), and V2P (vehicle-to-pedestrian). V2X communication can be provided through PC5 interfaces and / or Uu interfaces.

[0005] Meanwhile, as more communication devices require larger communication capacities, the need for improved mobile broadband communication compared to existing Radio Access Technology (RAT) is emerging. Accordingly, communication systems considering services or terminals sensitive to reliability and latency are being discussed; next-generation radio access technology that incorporates improved mobile broadband communication, Massive Machine Type Communication (MTC), and Ultra-Reliable and Low Latency Communication (URLC) can be referred to as new radio access technology (new RAT) or new radio (NR). Vehicle-to-everything (V2X) communication can also be supported in NR.

[0006] Figure 1 is a diagram illustrating a comparison between V2X communication based on RAT prior to NR and V2X communication based on NR.

[0007] Regarding V2X communication, prior to NR, RATs mainly discussed methods for providing safety services based on V2X messages such as BSM (Basic Safety Message), CAM (Cooperative Awareness Message), and DENM (Decentralized Environmental Notification Message). V2X messages can include location information, dynamic information, attribute information, etc. For example, a terminal can transmit a CAM of the periodic message type and / or a DENM of the event-triggered message type to another terminal.

[0008] For example, the CAM may include basic vehicle information such as dynamic state information of the vehicle, such as direction and speed, static data of the vehicle, such as dimensions, external lighting conditions, and route history. For example, a terminal may broadcast the CAM, and the latency of the CAM may be less than 100ms. For example, in the event of an unexpected situation such as a vehicle breakdown or accident, the terminal may generate a DENM and transmit it to other terminals. For example, all vehicles within the transmission range of the terminal may receive the CAM and / or DENM. In this case, the DENM may have a higher priority than the CAM.

[0009] Since then, regarding V2X communication, various V2X scenarios have been presented in NR. For example, various V2X scenarios may include vehicle platooning, advanced driving, extended sensors, remote driving, etc.

[0010] For example, based on vehicle platooning, vehicles can dynamically form groups and move together. For example, to perform platoon operations based on vehicle platooning, vehicles belonging to said group can receive periodic data from the lead vehicle. For example, vehicles belonging to said group can use said periodic data to reduce or increase the distance between vehicles.

[0011] For example, based on enhanced driving, vehicles can be semi-automated or fully automated. For example, each vehicle can adjust trajectories or maneuvers based on data acquired from local sensors of nearby vehicles and / or nearby logical entities. Additionally, for example, each vehicle can mutually share driving intentions with nearby vehicles.

[0012] For example, based on extended sensors, raw data or processed data or live video data acquired through local sensors can be exchanged between vehicles, logical entities, pedestrian terminals and / or V2X application servers. Thus, for example, a vehicle can perceive an environment that is enhanced compared to the environment it can detect using its own sensors.

[0013] For example, based on remote driving, a remote driver or V2X application can operate or control a remote vehicle for a person unable to drive or for a remote vehicle located in a dangerous environment. For example, in cases where the route is predictable, such as in public transportation, cloud computing-based driving can be used for the operation or control of the remote vehicle. Additionally, access to a cloud-based back-end service platform, for example, can be considered for remote driving.

[0014] Meanwhile, methods to specify service requirements for various V2X scenarios, such as vehicle platooning, enhanced driving, extended sensors, and remote driving, are being discussed in NR-based V2X communication.

[0015] The technical problem that the present invention aims to solve is to provide a method for transmitting and receiving signals more accurately and efficiently.

[0016] The technical problems are not limited to those mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art to which the present invention belongs from the description below.

[0017] A method by a UE (User Equipment) according to one aspect comprises the steps of: receiving configuration information for a first transmission path and a second transmission path; receiving a first PDSCH (downlink physical shared channel) through the first transmission path; transmitting a first HARQ ACK (Hybrid Automatic Repeat reQuest Acknowledgement) information for the first PDSCH; and receiving a second PDSCH through the second transmission path, wherein (i) the second PDSCH is received after the transmission of the first HARQ ACK, and (ii) based on the second transmission path being associated with a non-terrestrial network (NTN), the UE determines whether the second PDSCH contains data corresponding to the first PDSCH, and based on the determination that the second PDSCH contains data corresponding to the first PDSCH, the transmission of the second HARQ ACK information for the second PDSCH may be omitted.

[0018] Alternatively, it may further include the step of receiving control information including reception timing information associated with the second transmission path associated with the HARQ process ID (identifier) ​​for the first PDSCH.

[0019] Alternatively, based on the fact that the second PDSCH having the HARQ process ID is received at a timing corresponding to the reception timing information, the second PDSCH may be determined to contain data corresponding to the first PDSCH.

[0020] Alternatively, the control information may further include first instruction information regarding the transmission of the same data through the first transmission path and the second transmission path, or second instruction information regarding whether to transmit duplicate data.

[0021] Alternatively, the above control information can be received via DCI (downlink control information).

[0022] Alternatively, based on the fact that the second PDSCH is received within a predefined time from the reception of the first PDSCH after the transmission of the first HARQ ACK, the UE determines whether the second PDSCH contains data corresponding to the first PDSCH, and the predefined time may be defined based on the propagation delay time associated with the NTN.

[0023] Alternatively, based on the fact that the second HARQ ACK information for the second PDSCH is a NACK (Negative ACK), it is determined that the second PDSCH does not contain data corresponding to the first PDSCH, and based on the fact that the second PDSCH does not contain data corresponding to the first PDSCH, the second HARQ ACK information may be transmitted.

[0024] Alternatively, the above-mentioned configuration information may include information for configuring the first transmission path and the second transmission path for CA (Carrier Aggregation), wherein the first transmission path is a transmission path associated with a TN (terrestrial network) and the second transmission path is a transmission path associated with an NTN.

[0025] According to another aspect, at least one non-transient computer-readable recording medium comprises instructions for performing operations when executed by at least one processor, said operations include receiving configuration information for a first transmission path and a second transmission path; receiving a first PDSCH (downlink physical shared channel) through the first transmission path; transmitting a first HARQ ACK (Hybrid Automatic Repeat reQuest Acknowledgement) information for the first PDSCH; receiving a second PDSCH through the second transmission path; and (i) receiving the second PDSCH after the transmission of the first HARQ ACK, and (ii) determining whether the second PDSCH contains data corresponding to the first PDSCH based on the second transmission path being associated with a non-terrestrial network (NTN), and based on the determination that the second PDSCH contains data corresponding to the first PDSCH, the transmission of the second HARQ ACK information for the second PDSCH may be omitted.

[0026] According to another aspect, the UE (User Equipment) is an RF (Radio Frequency) transceiver; The apparatus includes a processor connected to the RF transceiver, wherein the processor controls the RF transceiver to receive configuration information for a first transmission path and a second transmission path, receives a first PDSCH (downlink physical shared channel) through the first transmission path, transmits a first HARQ ACK (Hybrid Automatic Repeat reQuest Acknowledgement) information for the first PDSCH, and receives a second PDSCH through the second transmission path, wherein (i) the second PDSCH is received after the transmission of the first HARQ ACK, and (ii) the second PDSCH is determined to include data corresponding to the first PDSCH based on the fact that the second transmission path is associated with a non-terrestrial network (NTN), and the transmission of the second HARQ ACK information for the second PDSCH may be omitted based on the determination that the second PDSCH includes data corresponding to the first PDSCH.

[0027] According to another aspect, a processing device controlling a UE (User Equipment) comprises at least one processor; and at least one memory connected to the at least one processor and storing instructions that perform operations when executed by the at least one processor, wherein the operations include receiving configuration information for a first transmission path and a second transmission path; receiving a first PDSCH (downlink physical shared channel) through the first transmission path; transmitting a first HARQ ACK (Hybrid Automatic Repeat reQuest Acknowledgement) information for the first PDSCH; and receiving a second PDSCH through the second transmission path. and (i) the second PDSCH is received after the transmission of the first HARQ ACK, and (ii) the second transmission path is associated with a non-terrestrial network (NTN), and the second PDSCH is determined to include data corresponding to the first PDSCH, and based on the determination that the second PDSCH includes data corresponding to the first PDSCH, the transmission of the second HARQ ACK information for the second PDSCH may be omitted.

[0028] A method by a base station according to another aspect comprises the steps of: transmitting configuration information for a first transmission path and a second transmission path to a UE (User Equipment); transmitting a first PDSCH (downlink physical shared channel) to the UE through the first transmission path; transmitting a second PDSCH to the UE through the second transmission path; and receiving a first HARQ ACK (Hybrid Automatic Repeat reQuest Acknowledgement) information for the first PDSCH from the UE, wherein, based on (i) the second transmission path is associated with a non-terrestrial network (NTN) and (ii) the first PDSCH and the second PDSCH contain the same data, the base station may not perform retransmission for the second PDSCH through the second transmission path even if the second HARQ ACK information for the second PDSCH is not received.

[0029] A base station according to another aspect includes an RF (Radio Frequency) transceiver; and a processor connected to the RF transceiver, wherein the processor controls the RF transceiver to transmit configuration information for a first transmission path and a second transmission path to a UE (User Equipment), transmits a first PDSCH (downlink physical shared channel) to the UE through the first transmission path, transmits a second PDSCH to the UE through the second transmission path, and receives a first HARQ ACK (Hybrid Automatic Repeat reQuest Acknowledgement) information for the first PDSCH from the UE, and based on (i) the second transmission path is associated with a non-terrestrial network (NTN), and (ii) the first PDSCH and the second PDSCH contain the same data, the processor may not perform retransmission of the second PDSCH through the second transmission path even if the second HARQ ACK information for the second PDSCH is not received.

[0030] According to one embodiment of the present invention, signals can be transmitted and received more accurately and efficiently in a wireless communication system. According to one example, the redundant transmission of HARQ ACK information for the same data due to the difference in propagation delay time between the NTN path and the TN path can be effectively prevented, thereby minimizing unnecessary use of HARQ feedback resources.

[0031] The effects obtainable from various embodiments are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art from the description below.

[0032] The drawings attached to this specification are intended to provide an understanding of the present invention, to illustrate various embodiments of the invention, and to explain the principles of the invention together with the description in the specification.

[0033] Figure 1 is a diagram illustrating a comparison between V2X communication based on RAT prior to NR and V2X communication based on NR.

[0034] Figure 2 shows the structure of an LTE system.

[0035] Figure 3 shows the structure of the NR system.

[0036] Figure 4 shows the structure of a wireless frame of NR.

[0037] Figure 5 shows the slot structure of an NR frame.

[0038] FIG. 6 shows a communication structure that can be provided in a 6G system according to one embodiment of the present disclosure.

[0039] FIG. 7 shows an electromagnetic spectrum according to one embodiment of the present disclosure.

[0040] Figure 8 shows the radio protocol architecture for SL communication.

[0041] Figure 9 shows a terminal performing V2X or SL communication.

[0042] Figure 10 shows a resource unit for V2X or SL communication.

[0043] FIG. 11 shows an example of a BWP according to one embodiment of the present disclosure.

[0044] FIG. 12 illustrates a procedure in which a terminal performs V2X or SL communication according to a resource allocation mode, according to one embodiment of the present disclosure.

[0045] FIG. 13 shows an example of a general NTN scenario based on a transparent payload or a regenerated payload according to one embodiment.

[0046] Figures 14 to 22 are diagrams illustrating how a UE performs a handover in relation to a satellite gNB.

[0047] Figures 23 and 24 are drawings for explaining the coverage of NTN.

[0048] Figures 25 and 26 are diagrams illustrating a method of transferring SDU from an RLC layer to an upper layer.

[0049] FIGS. 27 and 28 are diagrams illustrating a method for transmitting and receiving HARQ ACK information when the UE and gNB are connected via a TN path and an NTN path.

[0050] FIG. 29 is a diagram illustrating a method for a UE to transmit HARQ ACK information for data received through a first transmission path and a second transmission path.

[0051] FIG. 30 is a diagram illustrating a method for a base station to receive HARQ ACK information for data received through a first transmission path and a second transmission path.

[0052] FIG. 31 illustrates a communication system to which the present invention is applied.

[0053] FIG. 32 illustrates a wireless device that can be applied to the present invention.

[0054] FIG. 33 illustrates another example of a wireless device to which the present invention applies. The wireless device may be implemented in various forms depending on the use-example / service.

[0055] FIG. 34 illustrates a vehicle or autonomous vehicle to which the present invention is applied.

[0056] A wireless communication system is a multiple access system that supports communication with multiple users by sharing available system resources (e.g., bandwidth, transmission power, etc.). Examples of multiple access systems include CDMA (code division multiple access), FDMA (frequency division multiple access), TDMA (time division multiple access), OFDMA (orthogonal frequency division multiple access), SC-FDMA (single carrier frequency division multiple access), and MC-FDMA (multi carrier frequency division multiple access) systems.

[0057] Sidelink refers to a communication method in which User Equipment (UE) establishes a direct link to directly exchange voice or data between terminals without passing through a Base Station (BS). Sidelink is being considered as a solution to address the burden on base stations caused by rapidly increasing data traffic.

[0058] V2X (vehicle-to-everything) refers to a communication technology that exchanges information with other vehicles, pedestrians, and infrastructure-equipped objects through wired or wireless communication. V2X can be classified into four types: V2V (vehicle-to-vehicle), V2I (vehicle-to-infrastructure), V2N (vehicle-to-network), and V2P (vehicle-to-pedestrian). V2X communication can be provided through PC5 interfaces and / or Uu interfaces.

[0059] Meanwhile, as more communication devices require larger communication capacities, the need for improved mobile broadband communication compared to existing Radio Access Technology (RAT) is emerging. Accordingly, communication systems considering services or terminals sensitive to reliability and latency are being discussed; next-generation radio access technology that incorporates improved mobile broadband communication, Massive MTC, and URLLC (Ultra-Reliable and Low Latency Communication) can be referred to as new radio access technology (new RAT) or new radio (NR). Vehicle-to-everything (V2X) communication can also be supported in NR.

[0060] The following technologies can be used in various wireless communication systems such as CDMA (code division multiple access), FDMA (frequency division multiple access), TDMA (time division multiple access), OFDMA (orthogonal frequency division multiple access), and SC-FDMA (single carrier frequency division multiple access). CDMA can be implemented using wireless technologies such as UTRA (universal terrestrial radio access) or CDMA2000. TDMA can be implemented using wireless technologies such as GSM (global system for mobile communications), GPRS (general packet radio service), and EDGE (enhanced data rates for GSM evolution). OFDMA can be implemented using wireless technologies such as IEEE (institute of electrical and electronics engineers) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, and E-UTRA (evolved UTRA). IEEE 802.16m is an evolution of IEEE 802.16e and provides backward compatibility with systems based on IEEE 802.16e. UTRA is part of UMTS (universal mobile telecommunications system). 3GPP (3rd generation partnership project) LTE (long term evolution) is part of E-UMTS (evolved UMTS) which uses E-UTRA (evolved-UMTS terrestrial radio access), employing OFDMA in the downlink and SC-FDMA in the uplink.LTE-A (advanced) is an evolution of 3GPP LTE.

[0061] 5G NR is a successor technology to LTE-A and is a new clean-slate type mobile communication system with characteristics such as high performance, low latency, and high availability. 5G NR can utilize all available spectrum resources, ranging from low frequency bands below 1 GHz to mid-frequency bands from 1 GHz to 10 GHz, and high frequency (millimeter wave) bands above 24 GHz.

[0062] For clarity of explanation, the description focuses on LTE-A or 5G NR, but the technical concept of the embodiment(s) is not limited thereto.

[0063] Figure 2 shows the structure of an applicable LTE system. This can be called an E-UTRAN (Evolved-UMTS Terrestrial Radio Access Network), or an LTE (Long Term Evolution) / LTE-A system.

[0064] Referring to FIG. 2, the E-UTRAN includes a base station (20; Base Station, BS) that provides a control plane and a user plane to a terminal (10). The terminal (10) may be fixed or mobile and may be referred to by other terms such as MS (Mobile Station), UT (User Terminal), SS (Subscriber Station), MT (Mobile Terminal), or Wireless Device. The base station (20) refers to a fixed station that communicates with the terminal (10) and may be referred to by other terms such as eNB (evolved-NodeB), BTS (Base Transceiver System), or Access Point.

[0065] Base stations (20) can be connected to each other through an X2 interface. The base station (20) is connected to the EPC (Evolved Packet Core, 30) through the S1 interface, more specifically to the MME (Mobility Management Entity) through the S1-MME and to the S-GW (Serving Gateway) through the S1-U.

[0066] The EPC (30) consists of an MME, an S-GW, and a P-GW (Packet Data Network-Gateway). The MME holds information regarding the terminal's connection information or capabilities, and this information is primarily used for managing the terminal's mobility. The S-GW is a gateway with an E-UTRAN as its endpoint, and the P-GW is a gateway with a PDN as its endpoint.

[0067] The layers of the Radio Interface Protocol between a terminal and a network can be classified into L1 (Layer 1), L2 (Layer 2), and L3 (Layer 3) based on the lower three layers of the Open System Interconnection (OSI) model, which is widely known in communication systems. Among these, the Physical Layer, belonging to Layer 1, provides Information Transfer Services using a physical channel, while the Radio Resource Control (RRC) layer, located at Layer 3, performs the role of controlling radio resources between the terminal and the network. To this end, the RRC layer exchanges RRC messages between the terminal and the base station.

[0068] Figure 3 shows the structure of the NR system.

[0069] Referring to FIG. 3, the NG-RAN may include gNBs and / or eNBs that provide user plane and control plane protocol termination to terminals. FIG. 7 illustrates a case where only gNBs are included. The gNBs and eNBs are connected to each other via Xn interfaces. The gNBs and eNBs are connected to the 5G Core Network (5GC) via NG interfaces. More specifically, they are connected to the access and mobility management function (AMF) via NG-C interfaces and to the user plane function (UPF) via NG-U interfaces.

[0070] Figure 4 shows the structure of a wireless frame of NR.

[0071] Referring to FIG. 4, radio frames can be used for uplink and downlink transmission in NR. The radio frame has a length of 10 ms and can be defined as two 5 ms half-frames (HF). A half-frame may contain five 1 ms subframes (SF). A subframe may be divided into one or more slots, and the number of slots within a subframe may be determined by the subcarrier spacing (SCS). Each slot may contain 12 or 14 OFDM(A) symbols according to the cyclic prefix (CP).

[0072] When normal CP is used, each slot may contain 14 symbols. When extended CP is used, each slot may contain 12 symbols. Here, the symbols may include OFDM symbols (or CP-OFDM symbols) and SC-FDMA (Single Carrier - FDMA) symbols (or DFT-s-OFDM (Discrete Fourier Transform-spread-OFDM) symbols).

[0073] Table 1 below shows the number of symbols per slot ((N) according to the SCS setting (u) when normal CP is used. slot symb ), number of slots per frame((N frame,u slot ) and the number of slots per subframe((N subframe,u slot ) exemplifies.

[0074] SCS (15*2 u )N slot symb N frame,u slot N subframe,u slot 15KHz (u=0)1410130KHz (u=1)1420260KHz (u=2)14404120KHz (u=3)14808240KHz (u=4)1416016

[0075] Table 2 shows the number of symbols per slot, the number of slots per frame, and the number of slots per subframe according to the SCS when an extended CP is used.

[0076] SCS (15*2 u )N slot symb N frame,u slot N subframe,u slot 60KHz (u=2)12404

[0077] In an NR system, the OFDM(A) numerology (e.g., SCS, CP length, etc.) can be configured differently among multiple cells that are merged into a single terminal. Accordingly, the (absolute time) interval of a time resource (e.g., subframe, slot, or TTI) (collectively referred to as TU (Time Unit) for convenience) composed of the same number of symbols can be configured differently among the merged cells.

[0078] In NR, multiple numerologies or SCSs may be supported to support various 5G services. For example, if the SCS is 15 kHz, a wide area in traditional cellular bands may be supported, and if the SCS is 30 kHz / 60 kHz, dense-urban, lower latency, and wider carrier bandwidth may be supported. If the SCS is 60 kHz or higher, a bandwidth greater than 24.25 GHz may be supported to overcome phase noise.

[0079] The NR frequency band can be defined by two types of frequency ranges. The two types of frequency ranges may be FR1 and FR2. The numerical values ​​of the frequency ranges may change, for example, as shown in Table 3 below. Among the frequency ranges used in an NR system, FR1 may mean "sub 6GHz range" and FR2 may mean "above 6GHz range" and may be referred to as millimeter wave (mmW).

[0080] Frequency Range designationCorresponding frequency rangeSubcarrier Spacing (SCS)FR1450MHz - 6000MHz15, 30, 60kHzFR224250MHz - 52600MHz60, 120, 240kHz

[0081] As described above, the numerical value of the frequency range of the NR system may change. For example, FR1 may include a band of 410 MHz to 7125 MHz as shown in Table 4 below. That is, FR1 may include a frequency band of 6 GHz (or 5850, 5900, 5925 MHz, etc.) or higher. For example, the frequency band of 6 GHz (or 5850, 5900, 5925 MHz, etc.) or higher included within FR1 may include an unlicensed band. The unlicensed band may be used for various purposes, for example, for communication for vehicles (e.g., autonomous driving).

[0082] Frequency Range designationCorresponding frequency rangeSubcarrier Spacing (SCS)FR1410MHz - 7125MHz15, 30, 60kHzFR224250MHz - 52600MHz60, 120, 240kHz

[0083] Figure 5 shows the slot structure of an NR frame.

[0084] Referring to FIG. 5, a slot contains multiple symbols in the time domain. For example, in the case of a normal CP, one slot may contain 14 symbols, but in the case of an extended CP, one slot may contain 12 symbols. Alternatively, in the case of a normal CP, one slot may contain 7 symbols, but in the case of an extended CP, one slot may contain 6 symbols.

[0085] A carrier includes multiple subcarriers in the frequency domain. A Resource Block (RB) can be defined as multiple (e.g., 12) consecutive subcarriers in the frequency domain. A Bandwidth Part (BWP) can be defined as multiple consecutive (P)RBs ((Physical) Resource Blocks) in the frequency domain and can correspond to a single numerology (e.g., SCS, CP length, etc.). A carrier can include up to N (e.g., 5) BWPs. Data communication can be performed through the active BWPs. Each element can be referred to as a Resource Element (RE) in a resource grid and can be mapped to a single complex symbol.

[0086] Meanwhile, a wireless interface between terminals or a wireless interface between a terminal and a network may be composed of L1, L2, and L3 layers. In various embodiments of the present disclosure, L1 layer may refer to the physical layer. Additionally, for example, L2 layer may refer to at least one of the MAC layer, RLC layer, PDCP layer, and SDAP layer. Additionally, for example, L3 layer may refer to the RRC layer.

[0087] FIG. 6 illustrates a communication structure that can be provided in a 6G system according to one embodiment of the present disclosure. The embodiment of FIG. 6 can be combined with various embodiments of the present disclosure.

[0088] New network characteristics in 6G may be as follows.

[0089] - Satellite Integrated Network

[0090] - Connected Intelligence: Unlike previous generations of wireless communication systems, 6G is innovative and will update wireless evolution from "connected things" to "connected intelligence." AI can be applied at each stage of the communication process (or at each step of the signal processing described below).

[0091] - Seamless integration of wireless information and energy transfer

[0092] - Ubiquitous Super 3D Connectivity: Connectivity to the network and core network functions of drones and very low Earth orbit satellites will create Super 3D connectivity in 6G ubiquitous.

[0093] Some general requirements regarding the new network characteristics of 6G mentioned above may be as follows.

[0094] - Small cell networks

[0095] - Ultra-dense heterogeneous network

[0096] - High-capacity backhaul

[0097] - Radar technology integrated with mobile technology: High-precision localization (or location-based services) through communication is one of the functions of 6G wireless communication systems. Therefore, radar systems will be integrated with 6G networks.

[0098] - Softwarization and virtualization

[0099] The core implementation technologies of the 6G system are described below.

[0100] - Artificial Intelligence: Introducing AI into communications can streamline and enhance real-time data transmission. AI can determine how complex target tasks are performed using numerous analyses. In other words, AI can increase efficiency and reduce processing latency. Time-consuming tasks such as handover, network selection, and resource scheduling can be performed instantly using AI. AI can also play a significant role in M2M, machine-to-human, and human-to-machine communication. Furthermore, AI can enable rapid communication in Brain-Computer Interfaces (BCI). AI-based communication systems can be supported by metamaterials, intelligent structures, intelligent networks, intelligent devices, intelligent cognitive radios, self-sustaining wireless networks, and machine learning.

[0101] - THz Communication: Data transmission rates can be increased by expanding bandwidth. This can be achieved by using sub-THz communication with wide bandwidth and applying advanced large-scale MIMO technology. THz waves, also known as sub-millimeter radiation, generally refer to a frequency band between 0.1 THz and 10 THz with corresponding wavelengths ranging from 0.03 mm to 3 mm. The 100 GHz-300 GHz band range (Sub-THz band) is considered the primary portion of the THz band for cellular communication. Adding the Sub-THz band to the mmWave band increases 6G cellular communication capacity. Among the defined THz bands, the 300 GHz-3 THz band is located in the far-infrared (IR) frequency band. Although the 300 GHz-3 THz band is part of the optical band, it lies at the boundary of the optical band and immediately following the RF band. Therefore, this 300 GHz-3 THz band exhibits similarities to RF.

[0102] FIG. 7 illustrates an electromagnetic spectrum according to one embodiment of the present disclosure. The embodiment of FIG. 7 may be combined with various embodiments of the present disclosure. Key characteristics of THz communication include (i) a widely available bandwidth to support very high data transmission rates, and (ii) high path loss occurring at high frequencies (highly directional antennas are indispensable). The narrow beam width generated by highly directional antennas reduces interference. The small wavelength of THz signals allows a much larger number of antenna elements to be integrated into devices and BSs operating in this band. This enables the use of advanced adaptive array techniques that can overcome range limitations.

[0103] - Large-scale MIMO technology

[0104] - Hologram beamforming (HBF)

[0105] - Optical wireless technology

[0106] - Free Space Optical Transmission Backhaul Network (FSO backhaul network)

[0107] - Quantum communication

[0108] - Cell-free communication

[0109] - Integration of wireless information and power transmission

[0110] - Integration of wireless communication and sensing

[0111] - Integrated access and backhaul network

[0112] - Big data analysis

[0113] - Reconfigurable intelligent metasurface

[0114] - Metaverse

[0115] - blockchain

[0116] - Unmanned Aerial Vehicle (UAV): UAVs or drones will be a critical element in 6G wireless communication. In most cases, high-speed data wireless connectivity can be provided using UAV technology. Base station (BS) entities can be installed on UAVs to provide cellular connectivity. UAVs can possess specific features not found in fixed BS infrastructure, such as easy deployment, robust line-of-sight links, and controlled degrees of freedom for mobility. During emergencies, such as natural disasters, the deployment of ground communication infrastructure is not economically feasible, and sometimes services cannot be provided in volatile environments. UAVs can easily handle these situations. UAVs will become a new paradigm in the field of wireless communication. This technology facilitates the three fundamental requirements of wireless networks: eMBB, URLLC, and mMTC. UAVs can also support various purposes, such as enhancing network connectivity, fire detection, disaster emergency services, security and surveillance, pollution monitoring, parking monitoring, and accident monitoring. Therefore, UAV technology is recognized as one of the most critical technologies for 6G communication.

[0117] - Autonomous Driving (Self-Driving): V2X (Vehicle to Everything), a core element in building autonomous driving infrastructure, refers to technologies that enable vehicles to communicate and share with various elements on the road for autonomous driving, such as wireless communication between vehicles (Vehicle to Vehicle, V2V) and between vehicles and infrastructure (Vehicle to Infrastructure, V2I). Fast transmission speeds and low-latency technologies are essential to maximize autonomous driving performance and ensure high safety. Furthermore, future autonomous driving may go beyond merely delivering warning or guidance messages to the driver to actively intervene in vehicle operation and directly control the vehicle in dangerous situations. Since the amount of information to be transmitted and received may become massive for this purpose, it is expected that 6G will be able to maximize autonomous driving through faster transmission speeds and lower latency compared to 5G.

[0118] FIG. 8 illustrates a radio protocol architecture for SL communication. Specifically, FIG. 8 (a) shows the user plane protocol stack of NR, and FIG. 8 (b) shows the control plane protocol stack of NR.

[0119] The Sidelink Synchronization Signal (SLSS) and synchronization information are described below.

[0120] SLSS is an SL-specific sequence that may include PSSS (Primary Sidelink Synchronization Signal) and SSSS (Secondary Sidelink Synchronization Signal). The PSSS may be referred to as S-PSS (Sidelink Primary Synchronization Signal), and the SSSS may be referred to as S-SSS (Sidelink Secondary Synchronization Signal). For example, length-127 M-sequences may be used for S-PSS, and length-127 Gold sequences may be used for S-SSS. For example, a terminal may use S-PSS to detect the initial signal and obtain synchronization. For example, a terminal may use S-PSS and S-SSSS to obtain detailed synchronization and detect the synchronization signal ID.

[0121] PSBCH (Physical Sidelink Broadcast Channel) may be a (broadcast) channel through which basic (system) information that a terminal must know first is transmitted before transmitting or receiving SL signals. For example, the basic information may include information related to SLSS, Duplex Mode (DM), TDD UL / DL (Time Division Duplex Uplink / Downlink) configuration, information related to resource pools, types of applications related to SLSS, subframe offsets, broadcast information, etc. For example, to evaluate PSBCH performance, in NR V2X, the payload size of PSBCH may be 56 bits, including a 24-bit CRC.

[0122] S-PSS, S-SSS, and PSBCH may be included in a block format that supports periodic transmission (e.g., SL SS (Synchronization Signal) / PSBCH block, hereinafter S-SSB (Sidelink-Synchronization Signal Block)). The S-SSB may have the same numerology (i.e., SCS and CP lengths) as the PSCCH (Physical Sidelink Control Channel) / PSSCH (Physical Sidelink Shared Channel) within the carrier, and the transmission bandwidth may be within a (pre-)set SL BWP (Sidelink BWP). For example, the bandwidth of the S-SSB may be 11 RB (Resource Block). For example, the PSBCH may span 11 RB. Additionally, the frequency position of the S-SSB may be (pre-)set. Therefore, the terminal does not need to perform hypothesis detection at the frequency to discover the S-SSB in the carrier.

[0123] Meanwhile, in an NR SL system, multiple numerologies having different SCS and / or CP lengths may be supported. In this case, as the SCS increases, the length of the time resource for the transmitting terminal to transmit S-SSBs may decrease. Consequently, the coverage of S-SSBs may decrease. Therefore, to ensure S-SSB coverage, the transmitting terminal may transmit one or more S-SSBs to the receiving terminal within a single S-SSB transmission cycle according to the SCS. For example, the number of S-SSBs transmitted by the transmitting terminal to the receiving terminal within a single S-SSB transmission cycle may be pre-configured or configured for the transmitting terminal. For example, the S-SSB transmission cycle may be 160ms. For example, an S-SSB transmission cycle of 160ms may be supported for all SCSs.

[0124] For example, if the SCS is 15 kHz at FR1, the transmitting terminal may transmit one or two S-SSBs to the receiving terminal within one S-SSB transmission cycle. For example, if the SCS is 30 kHz at FR1, the transmitting terminal may transmit one or two S-SSBs to the receiving terminal within one S-SSB transmission cycle. For example, if the SCS is 60 kHz at FR1, the transmitting terminal may transmit one, two, or four S-SSBs to the receiving terminal within one S-SSB transmission cycle.

[0125] For example, if the SCS is 60 kHz at FR2, the transmitting terminal can transmit 1, 2, 4, 8, 16, or 32 S-SSBs to the receiving terminal within one S-SSB transmission cycle. For example, if the SCS is 120 kHz at FR2, the transmitting terminal can transmit 1, 2, 4, 8, 16, 32, or 64 S-SSBs to the receiving terminal within one S-SSB transmission cycle.

[0126] Meanwhile, when the SCS is 60 kHz, two types of CP may be supported. Additionally, depending on the CP type, the structure of the S-SSB transmitted by the transmitting terminal to the receiving terminal may differ. For example, the CP type may be Normal CP (NCP) or Extended CP (ECP). Specifically, for example, if the CP type is NCP, the number of symbols mapping PSBCH within the S-SSB transmitted by the transmitting terminal may be 9 or 8. On the other hand, for example, if the CP type is ECP, the number of symbols mapping PSBCH within the S-SSB transmitted by the transmitting terminal may be 7 or 6. For example, PSBCH may be mapped to the first symbol within the S-SSB transmitted by the transmitting terminal. For example, the receiving terminal receiving the S-SSB may perform Automatic Gain Control (AGC) operation during the first symbol interval of the S-SSB.

[0127] Figure 9 shows a terminal performing V2X or SL communication.

[0128] Referring to FIG. 9, in V2X or SL communication, the term terminal may primarily refer to a user's terminal. However, if network equipment such as a base station transmits and receives signals according to the communication method between terminals, the base station may also be considered a type of terminal. For example, terminal 1 may be a first device (100), and terminal 2 may be a second device (200).

[0129] For example, terminal 1 can select a resource unit corresponding to a specific resource within a resource pool, which represents a set of resources. Then, terminal 1 can transmit an SL signal using the said resource unit. For example, terminal 2, which is a receiving terminal, can be configured with a resource pool in which terminal 1 can transmit a signal, and can detect terminal 1's signal within said resource pool.

[0130] Here, if terminal 1 is within the connection range of the base station, the base station may inform terminal 1 of the resource pool. On the other hand, if terminal 1 is outside the connection range of the base station, another terminal may inform terminal 1 of the resource pool, or terminal 1 may use a pre-configured resource pool.

[0131] Generally, a resource pool can be composed of multiple resource units, and each terminal can select one or more resource units to use for its SL signal transmission.

[0132] Figure 10 shows a resource unit for V2X or SL communication.

[0133] Referring to FIG. 10, the total frequency resources of the resource pool can be divided into NF units, and the total time resources of the resource pool can be divided into NT units. Thus, a total of NF * NT resource units can be defined within the resource pool. FIG. 10 illustrates an example where the resource pool is repeated in a period of NT subframes.

[0134] As shown in FIG. 10, a single resource unit (e.g., Unit #0) may appear repeatedly over time. Alternatively, to obtain diversity effects in the time or frequency dimension, the index of the physical resource unit to which a single logical resource unit is mapped may change in a predetermined pattern over time. In this structure of resource units, a resource pool may refer to a set of resource units that a terminal intending to transmit an SL signal can use for transmission.

[0135] Resource pools can be subdivided into several types. For example, depending on the content of the SL signals transmitted from each resource pool, resource pools can be classified as follows.

[0136] (1) A Scheduling Assignment (SA) may be a signal containing information such as the location of the resource used by the transmitting terminal for transmission of the SL data channel, the Modulation and Coding Scheme (MCS) or Multiple Input Multiple Output (MIMO) transmission method required for demodulation of the data channel, and Timing Advance (TA). The SA may also be multiplexed and transmitted together with the SL data on the same resource unit, in which case the SA resource pool may refer to a resource pool in which the SA is multiplexed and transmitted together with the SL data. The SA may also be called the SL control channel.

[0137] (2) A Physical Sidelink Shared Channel (PSSCH) may be a resource pool used by a transmitting terminal to transmit user data. If SA is multiplexed and transmitted along with SL data on the same resource unit, only the form of the SL data channel excluding SA information can be transmitted from the resource pool for the SL data channel. In other words, REs (Resource Elements) that were used to transmit SA information on individual resource units within the SA resource pool can still be used to transmit SL data in the resource pool of the SL data channel. For example, the transmitting terminal can transmit by mapping the PSSCH to a succession of PRBs.

[0138] (3) The discovery channel may be a resource pool for a transmitting terminal to transmit information such as its ID. Through this, the transmitting terminal can enable adjacent terminals to discover it.

[0139] Even if the content of the SL signal described above is the same, different resource pools may be used depending on the transmission and reception attributes of the SL signal. For example, even if the same SL data channel or discovery message is used, it may be divided into different resource pools depending on the method of determining the transmission timing of the SL signal (e.g., whether it is transmitted at the time of reception of the synchronization reference signal or whether it is transmitted by applying a certain timing advance at the time of reception), the method of resource allocation (e.g., whether the base station assigns the transmission resource of an individual signal to the individual transmission terminal or whether the individual transmission terminal selects the individual signal transmission resource itself from within the resource pool), the signal format (e.g., the number of symbols occupied by each SL signal in one subframe, or the number of subframes used for the transmission of one SL signal), the signal strength from the base station, the transmission power strength of the SL terminal, etc.

[0140] FIG. 11 illustrates an example of a BWP according to an embodiment of the present disclosure. The embodiment of FIG. 11 may be combined with various embodiments of the present disclosure. In the embodiment of FIG. 11, it is assumed that there are three BWPs.

[0141] Referring to FIG. 11, the common resource block (CRB) may be a numbered carrier resource block extending from one end of the carrier band to the other. And, the PRB may be a numbered resource block within each BWP. Point A may indicate a common reference point for the resource block grid.

[0142] A BWP can be configured by point A, an offset from point A (NstartBWP), and a bandwidth (NsizeBWP). For example, point A may be an external reference point of the PRB of a carrier where the subcarrier 0 of all numerologies (e.g., all numerologies supported by the network on that carrier) is aligned. For example, the offset may be the PRB interval between the lowest subcarrier in a given numerology and point A. For example, the bandwidth may be the number of PRBs in a given numerology.

[0143] SLSS (Sidelink Synchronization Signal) is a sidelink-specific sequence and may include PSSS (Primary Sidelink Synchronization Signal) and SSSS (Secondary Sidelink Synchronization Signal). The PSSS may be referred to as S-PSS (Sidelink Primary Synchronization Signal), and the SSSS may be referred to as S-SSS (Sidelink Secondary Synchronization Signal). For example, length-127 M-sequences may be used for S-PSS, and length-127 Gold sequences may be used for S-SSS. For example, a terminal may use S-PSS to detect the initial signal and obtain synchronization. For example, a terminal may use S-PSS and S-SSSS to obtain detailed synchronization and detect the synchronization signal ID.

[0144] The PSBCH (Physical Sidelink Broadcast Channel) may be a (broadcast) channel through which basic (system) information that the terminal must know first is transmitted before transmitting or receiving SL signals. For example, the basic information may include information related to SLSS, Duplex Mode (DM), TDD UL / DL (Time Division Duplex Uplink / Downlink) configuration, information related to resource pools, types of applications related to SLSS, subframe offsets, broadcast information, etc. For example, to evaluate PSBCH performance, in NR V2X, the payload size of the PSBCH may be 56 bits, including a 24-bit CRC (Cyclic Redundancy Check).

[0145] S-PSS, S-SSS, and PSBCH may be included in a block format that supports periodic transmission (e.g., SL SS (Synchronization Signal) / PSBCH block, hereinafter S-SSB (Sidelink-Synchronization Signal Block)). The S-SSB may have the same numerology (i.e., SCS and CP lengths) as the PSCCH (Physical Sidelink Control Channel) / PSSCH (Physical Sidelink Shared Channel) within the carrier, and the transmission bandwidth may be within a (pre-)set SL BWP (Sidelink BWP). For example, the bandwidth of the S-SSB may be 11 RB (Resource Block). For example, the PSBCH may span 11 RB. Additionally, the frequency position of the S-SSB may be (pre-)set. Therefore, the terminal does not need to perform hypothesis detection at the frequency to discover the S-SSB in the carrier.

[0146] FIG. 12 illustrates a procedure in which a terminal performs V2X or SL communication according to a resource allocation mode, according to one embodiment of the present disclosure. The embodiment of FIG. 12 may be combined with various embodiments of the present disclosure.

[0147] Referring to FIG. 12(a), in resource allocation mode 1, the base station may schedule SL resources to be used by the terminal for SL transmission. For example, in step S1200, the base station may transmit information related to SL resources and / or information related to UL resources to the first terminal. For example, the UL resources may include PUCCH resources and / or PUSCH resources. For example, the UL resources may be resources for reporting SL HARQ feedback to the base station.

[0148] For example, the first terminal may receive information related to a dynamic grant (DG) resource and / or information related to a configured grant (CG) resource from the base station. For example, the CG resource may include a CG type 1 resource or a CG type 2 resource. In this specification, the DG resource may be a resource that the base station sets / assigns to the first terminal via downlink control information (DCI). In this specification, the CG resource may be a (periodic) resource that the base station sets / assigns to the first terminal via DCI and / or RRC messages. For example, in the case of a CG type 1 resource, the base station may transmit an RRC message containing information related to the CG resource to the first terminal. For example, in the case of a CG type 2 resource, the base station may transmit an RRC message containing information related to the CG resource to the first terminal, and the base station may transmit DCI related to the activation or release of the CG resource to the first terminal.

[0149] In step S1210, the first terminal may transmit a PSCCH (e.g., Sidelink Control Information or 1st-stage SCI) to the second terminal based on the resource scheduling. In step S1220, the first terminal may transmit a PSSCH (e.g., 2nd-stage SCI, MAC PDU, data, etc.) associated with the PSCCH to the second terminal. In step S1230, the first terminal may receive a PSFCH associated with the PSCCH / PSSCH from the second terminal. For example, HARQ feedback information (e.g., NACK information or ACK information) may be received from the second terminal via the PSFCH. In step S1240, the first terminal may transmit / report the HARQ feedback information to the base station via a PUCCH or PUSCH. For example, the HARQ feedback information reported to the base station may be information generated by the first terminal based on HARQ feedback information received from the second terminal. For example, the HARQ feedback information reported to the base station may be information generated by the first terminal based on a pre-set rule. For example, the DCI may be a DCI for scheduling SL.

[0150] Referring to FIG. 12(b), in resource allocation mode 2, the terminal can determine an SL transmission resource within an SL resource set by the base station / network or a preset SL resource. For example, the set SL resource or the preset SL resource may be a resource pool. For example, the terminal may autonomously select or schedule a resource for SL transmission. For example, the terminal may perform SL communication by selecting a resource itself within the set resource pool. For example, the terminal may select a resource itself within a selection window by performing a sensing and resource (re)selection procedure. For example, the sensing may be performed on a subchannel basis. For example, in step S1210, the first terminal, having selected a resource itself within the resource pool, may use the resource to transmit PSCCH (e.g., SCI (Sidelink Control Information) or 1st-stage SCI) to the second terminal. In step S1220, the first terminal can transmit PSSCH (e.g., 2nd-stage SCI, MAC PDU, data, etc.) associated with the PSCCH to the second terminal. In step S1230, the first terminal can receive PSFCH associated with the PSCCH / PSSCH from the second terminal.

[0151] Referring to FIG. 12 (a) or (b), for example, the first terminal may transmit an SCI to the second terminal over the PSCCH. Or, for example, the first terminal may transmit two consecutive SCIs (e.g., 2-stage SCIs) to the second terminal over the PSCCH and / or PSSCH. In this case, the second terminal may decode the two consecutive SCIs (e.g., 2-stage SCIs) to receive the PSSCH from the first terminal. In this specification, an SCI transmitted over the PSCCH may be referred to as the 1st SCI, the 1st SCI, the 1st-stage SCI, or the 1st-stage SCI format, and an SCI transmitted over the PSSCH may be referred to as the 2nd SCI, the 2nd SCI, the 2nd-stage SCI, or the 2nd-stage SCI format.

[0152] Referring to FIG. 12 (a) or (b), in step S1230, the first terminal can receive PSFCH. For example, the first terminal and the second terminal can determine a PSFCH resource, and the second terminal can use the PSFCH resource to transmit HARQ feedback to the first terminal.

[0153] Referring to FIG. 12(a), in step S1240, the first terminal can transmit SL HARQ feedback to the base station via PUCCH and / or PUSCH.

[0154] FIG. 13 shows an example of a general NTN scenario based on a transparent payload or a regenerated payload according to one embodiment.

[0155] Non-terrestrial networks (NTN): NTN may represent a network or network segment that uses RF (radio frequency) resources mounted on a satellite (or UAS (unmanned aerial system) platform).

[0156] Specifically, with reference to FIG. 13 (a), an example of a typical NTN scenario based on a transparent payload is shown, and FIG. 13 (b) shows an example of a typical NTN scenario based on a regenerative payload according to an embodiment of the present disclosure. The embodiment of FIG. 13 (a) or FIG. 13 (b) may be combined with various embodiments of the present disclosure.

[0157] Specifically, referring to FIG. 13 (a), a satellite (or UAS platform) can establish a service link with a UE. The satellite (or UAS platform) can be connected to a gateway via a feeder link. The satellite can be connected to a data network via the gateway. A beam footprint may refer to an area where signals transmitted by the satellite can be received.

[0158] Alternatively, referring to FIG. 13 (b), a satellite (or UAS platform) can establish a service link with a UE. A satellite (or UAS platform) connected to a UE can be connected to another satellite (or UAS platform) via inter-satellite links (ISL). Another satellite (or UAS platform) can be connected to a gateway via a feeder link. Based on a replay payload, the satellite can be connected to a data network via another satellite and a gateway. If no ISL exists between the satellite and another satellite, a feeder link between the satellite and the gateway may be required.

[0159] Meanwhile, FIG. 13 is merely an example of an NTN scenario, and NTN can be implemented based on various scenarios. For example, a satellite (or UAS platform) can implement a regenerative (with on-board processing) payload. For example, a satellite (or UAS platform) can generate multiple beams across a designated service area depending on the field of view of the satellite (or UAS platform). For example, the field of view of the satellite (or UAS platform) may vary depending on the on-board antenna diagram and the minimum elevation angle. For example, a regenerative payload may include radio frequency filtering, frequency conversion, and amplification. Thus, the waveform signal repeated by the payload may not be altered. For example, a regenerative payload may include radio frequency filtering, frequency conversion and amplification, demodulation / decoding, switching and / or routing, and coding / modulation. For example, the playback payload can be substantially the same as carrying all or part of the base station functions on a satellite (or UAS platform).

[0160] The Next Generation Radio Access Network (NG-RAN) is a Radio Access Network (RAN) for 5G that supports a configuration in which 5G base stations (gNB) are divided into a Central Unit (CU) and a Distributed Unit (DU). Various options for NTN-based NG-RAN architectures were reviewed, and it was concluded that there were no technical obstacles to supporting the identified architecture options.

[0161] The upper-layer protocol stack of NR is divided into the User Plane (UP) and the Control Plane (CP). The User Plane is responsible for data transmission, while the Control Plane is responsible for signal processing. In the case of the User Plane, long-distance propagation delay in an NTN environment has a significant impact; accordingly, the effects on the MAC, RLC, PDCP, and SDAP layers were analyzed. The analysis revealed that improvements are needed in the MAC layer for functions such as random access, discontinuous reception (DRX), scheduling requests, and HARQ (Hybrid Automatic Repeat Request). In the RLC layer, emphasis was placed on status reporting functions and the utilization of sequence numbers, while in the PDCP layer, the discarding of Service Data Units (SDU) and sequence number management were considered. For the SDAP layer, it was assessed that no separate modifications are required to support NTN.

[0162] In the control plane, mobility management procedures were reviewed with particular focus on the rapid mobility of LEO (Low Earth Orbit) satellites. For IDLE mode, the introduction of NTN-specific system information is required, and frequent Tracking Area Updates (TAU) can be prevented by introducing an Earth-fixed tracking area. Additionally, it may be beneficial to add auxiliary information for cell selection and re-selection. In Connected mode, improvements to the handover procedure were discussed to mitigate the problem of frequent handovers caused by rapid satellite movement.

[0163] From a physical layer perspective, link-level and system-level evaluations were performed in the S-band and Ka-band. According to the evaluation results, when appropriate satellite beam placement is applied, portable user terminals (UEs) can be serviced via LEO and GEO satellites in the S-band, and user terminals equipped with high-gain transmit / receive antennas (e.g., VSAT, phased array antennas) can be serviced by LEO and GEO satellites in the Ka-band as well as the S-band. Despite issues such as long-range propagation delay, large Doppler shift, and mobile cells in the NTN environment, it was concluded that the NR functions defined in Rel-15 and Rel-16 provide a sufficient foundation for supporting NTN. However, it was found that further functional improvements are needed in terms of timing relationships, uplink timing and frequency synchronization, and HARQ processing methods.

[0164] The NR NTN research topic in Release-17 aims to specify functional improvements for LEO and GEO-based NTN, while simultaneously considering implicit support for High Altitude Platform Systems (HAPS) and Air-to-Ground networks. The research topic includes the physical layer, protocols, and network architecture, as well as radio resource management, RF requirements, and frequency bands used. This study targets transparent payload architectures and Frequency Division Duplex (FDD) systems based on Earth fixed tracking zones, and assumes that all user terminals possess Global Navigation Satellite System (GNSS) capabilities.

[0165] Rel-16 NR performs continuous transmission based on up to 16 stop-and-wait HARQ processes. Since a single HARQ process cannot be reused until feedback is received regarding the previous transmission, in NTN environments with long Round-Trip Times (RTT), all HARQ processes wait for feedback, causing transmission congestion and consequently degrading communication efficiency. To mitigate this congestion, the number of HARQ processes has been expanded to 32, which can cover some Air-to-Ground scenarios. However, considering the RTTs of LEO and GEO-based NTNs, 32 HARQ processes alone are insufficient. Since further expanding the number of HARQ processes is undesirable, a method must be implemented that allows the same HARQ process to be reused before the entire RTT has elapsed. For downlink transmissions, if a HARQ process is reused before the RTT, HARQ feedback becomes unnecessary, and thus the feedback is disabled. There is no HARQ feedback in the uplink, and the gNB can dynamically decide whether to reuse the HARQ process before RTT by sending a grant for new data or retransmission.

[0166] For HARQ processes with HARQ feedback disabled, terminals do not need to wait for retransmission assignments after a certain period to conserve energy. If HARQ is not used for retransmission, link adaptation can be set to a target low block error rate, but a higher RLC retransmission rate and more frequent RLC status reporting are required to ensure overall reliability.

[0167] Considering the long-range RTT of NTN, some MAC and RLC timers are extended, and the terminal needs to (re)select a new satellite depending on the movement of the satellite. In this case, satellite selection is based on existing criteria, but may include new criteria such as the point in time when the satellite no longer provides service at the terminal location. Conditional handover is strengthened with new conditions based on the terminal location and the satellite coverage time for that location, and the measurement procedure can be improved with a terminal location-based triggering function.

[0168] Handover related to TN and NTN

[0169] Figures 14 to 22 are diagrams illustrating how a UE performs a handover in relation to a satellite gNB.

[0170] In the following, it is assumed that the UE must always maintain a connected state. While the UE may be connected to the ground-gNB within ground-gNB coverage, when it is outside ground-gNB coverage (e.g., deserts, oceans, mountainous regions), the UE must connect to the ground-gNB via a satellite or maintain connectivity via a satellite-gNB to keep the connection intact. Meanwhile, the above-mentioned UE may be a UAV UE mounted on or included in a UAV flying at high altitudes, and although the following explanation is based on the premise of a UE, it naturally applies to UAV UEs as well.

[0171] Here, being connected to the ground-gNB via a satellite may mean a case where the satellite gNB acts as a relay, enabling an indirect connection between the UE and the ground-gNB. On the other hand, the term satellite-gNB may mean that a gNB (or a device performing the gNB function) is installed on the satellite itself, enabling a direct connection with the UE.

[0172] Previously, satellite-based connections were discussed at 3GPP through NTN WI (work item). The following triggering conditions were added for cases where a ground UE performs an HO from a ground-gNB (A) to another ground-gNB (B) via satellite relay.

[0173] - Event D1: Distance between UE and a reference locationreferenceLocation1becomes larger than configured thresholddistanceThreshFromReference1and distance between UE and a reference locationreferenceLocation2becomes shorter than configured thresholddistanceThreshFromReference2;

[0174] - Event D2: Distance between UE and a moving reference location based onmovingReferenceLocationand its corresponding satellite ephemeris and epoch time broadcast inSIB19for the serving cell becomes larger than configured thresholddistanceThreshFromReference1and distance between UE and a moving reference location determined based onreferenceLocation2becomes shorter than configured thresholddistanceThreshFromReference2;

[0175] - 조건 이벤트 D1 (CondEvent D1): Distance between UE and a reference locationreferenceLocation1becomes larger than configured thresholddistanceThreshFromReference1and distance between UE and a reference locationreferenceLocation2of conditional reconfiguration candidate becomes shorter than configured thresholddistanceThreshFromReference2;

[0176] - 조건 이벤트 D2 (CondEvent D2): Distance between UE and a moving reference location determined based onmovingReferenceLocationand its corresponding satellite ephemeris and epoch time broadcast inSIB19for the serving cell becomes larger than configured thresholddistanceThreshFromReference1and distance between UE and a moving reference location determined based onreferenceLocation2of conditional reconfiguration candidate becomes shorter than configured thresholddistanceThreshFromReference2;

[0177] The reason location-based triggering conditions as described above were added in NTN is that signals received via satellite are transmitted over very long distances, making it difficult for the UE to measure changes in signal strength and trigger measurement reporting at an appropriate time.

[0178] For example, referring to FIG. 14, a UE on the ground may move out of coverage without knowing the difference in signal change between receiving a signal at the boundary of satellite_A and receiving a signal at the center of satellite_B. In this case, the continuity of service cannot be maintained with the existing HO triggering method. Considering this problem, a measurement event can be triggered when the UE moves a certain distance away from a defined (or configured) reference location A (reference location(A)) or (and / or) moves a certain distance closer to another defined (or configured) reference location B (reference location(B)), thereby satisfying service continuity. This location-based measurement triggering operation can be applied to the existing basic HO procedure or conditional HO procedure.

[0179] As such, when a UE communicates using a satellite, the role of the satellite can be distinguished into the following scenarios 1 and 2.

[0180] - Scenario 1: The satellite can simply receive a message transmitted by a ground gNB and transmit it transparently to a UE on the ground (transparency mode). Alternatively, it can receive a message from a UE on the ground and transmit it transparently to a gNB on the ground.

[0181] - Scenario 2: A method in which a satellite directly performs the functions of a communication gNB. For example, a communication unit capable of performing operations similar to (or the same as) a gNB may be attached to the satellite to receive messages transmitted by a ground gNB, interpret them to generate a message, and transmit the generated message to a UE on the ground (regenerative mode). Alternatively, it may be a method in which a message is received from a UE on the ground, interpreted to generate a message, and transmit the generated message to a gNB on the ground.

[0182] 1. Scenario 1

[0183] (1) Case 1-1

[0184] Referring to Fig. 15, a ground UE connected to gNB(A) can perform an HO procedure to gNB(B) via a transparency satellite (Case 1-1).

[0185] - 1. When a measurement report is triggered, a UE connected to a ground-gNB(A) can measure the signal strength of the current serving cell and neighbor cell and report it to the ground-gNB(A). In this case, the measurement report of the signal strength can be transmitted to the source gNB, the ground-gNB(A), via a satellite (or satellite relay).

[0186] - 2. The ground-gNB (A) can determine the HO and send a message requesting the HO to the target ground-gNB (B).

[0187] - 3. The ground-gNB (A) can receive permission for the HO request or an HO request ACK from the target ground-gNB (B).

[0188] - 4. The ground-gNB(A) can send an RRC message (e.g., RRCReconfiguration message) containing an HO-related command (HO command) to the UE.

[0189] - 5. At this time, the ground-gNB (A) may transmit an SN (Sequence Number) status Transfer message to the target ground-gNB (B). Here, the SN status Transfer message may be a message for transmitting the uplink PDCP SN receiver status and downlink PDCP SN transmitter status for the data radio bearer (DRB).

[0190] - 6. When the UE receives an RRCReconfiguration message, it can perform RACH to the target ground-gNB(B) and send an RRCReconfigurationComplete message to the target ground-gNB(B) to complete the HO procedure.

[0191] - 7. The UE is connected to the target ground-gNB (B), and 8. The target ground-gNB (B) can send a UE context release message to the source ground-gNB (A).

[0192] (2) Case 1-2

[0193] Referring to Fig. 16, a ground UE connected to gNB(B) via a Transparency satellite can perform an HO procedure from ground to gNB(A) (Case 1-2).

[0194] - 1. When a measurement report is triggered for a UE connected to the ground-gNB(B) via the transparency satellite, the UE can report the measurement value to the ground-gNB(B) via the transparency satellite.

[0195] - 2. (source) The ground-gNB(B) can decide on the HO and transmit a request for the HO to the target ground-gNB(A).

[0196] - 3. (source) Ground-gNB(B) can receive a response to the HO request from the target ground-gNB(A).

[0197] - 4. (Source) The ground-gNB(B) can transmit an RRCReconfiguration message to the UE to command HO via the transparency satellite.

[0198] - 5. At this time, the ground-gNB (B) can transmit the SN status transfer to the target ground-gNB (A).

[0199] - 6. After the UE performs the RACH procedure to the target ground-gNB(A) based on the RRCReconfiguration message, it can complete the HO by sending the RRCReconfigurationComplete message to the target ground-gNB(A).

[0200] - 7. The UE is connected to the target ground-gNB(A), and 8. The target ground-gNB(A) can send a UE context release message to the source ground-gNB(A).

[0201] When a UE performs an HO operation as in Case 1-1 and / or Case 1-2, the process of the UE reporting measurements via the transparency satellite and the (Source) ground-gNB transmitting an RRCReconfiguration message related to the measurement report to the UE (and / or the UE transmitting an RRCReconfigurationComplete to the target ground-gNB) can take significantly longer than a typical HO between a ground-gNB and a UE. In this case, the reported measurement values ​​may become out-of-date, which can be disadvantageous for the UE in selecting an appropriate target-gNB. Therefore, it may be more appropriate to apply a Conditional HO (CHO) method to operations related to an HO from a ground-gNB connected to gNB(A) to gNB(B) via the transparency satellite. This is explained in detail in Cases 1-3 and 1-4 below.

[0202] (3) Case 1-3

[0203] Referring to FIG. 17, a ground UE connected to ground-gNB(A) can perform a CHO procedure to ground-gNB(B) via a transparency satellite (Case 1-3).

[0204] - 1. A ground UE connected to the ground-gNB(A) can report a measurement value when a measurement report is triggered. For example, the ground UE can report the measurement value to the ground-gNB(A) via a transparency satellite (or satellite relay).

[0205] - 2. (source) The ground-gNB(A) can determine the HO based on the above-reported measurements and send an HO request message to the candidate target gNB(s).

[0206] - 3. The candidate target gNB(s) that accepted the above HO request may send a response accepting the HO to the (source) ground-gNB(A).

[0207] - 4. (source) The ground-gNB(A) can transmit configuration related to the CHO to the ground UE. For example, the ground-gNB(A) can provide configuration related to the CHO to the ground UE through an RRCReconfiguration message.

[0208] - 5. When the ground UE receives the configuration related to the CHO, it can send RRCReconfigurationComplete to the ground-gNB(A).

[0209] - 6. A ground-gNB(A) may provide an Early status transfer message to a candidate target gNB(s). Here, the Early status transfer message may include information about the RLC and PDCP layer status of the ground UE.

[0210] - 7. The ground UE can perform RACH on the target ground-gNB(B) through the transparency satellite and complete HO with the target ground-gNB(B) when the HO condition is satisfied based on the CHO condition according to the above CHO setting.

[0211] - 8. The target ground-gNB (B) can provide a message related to the success of the HO with the ground UE to the source ground-gNB (A).

[0212] - 9. Source ground-gNB (A) can provide SN status transfer messages to target ground-gNB (B).

[0213] - 10. The source ground-gNB (A) can send a message related to HO cancellation to the remaining candidate target gNBs, excluding the target ground-gNB (B) among the candidate target gNBs.

[0214] (4) Case 1-4

[0215] Referring to FIG. 18, a ground UE connected to a ground-gNB (B) via a Transparency satellite can perform a CHO to a ground-gNB (A) (Case 1-4).

[0216] - 1. When a measurement report is triggered, the ground UE performs a measurement report to the ground-gNB(B) via the transparency satellite (source).

[0217] - 2. (Source) The ground-gNB can determine the CHO and send an HO request message to the candidate target ground-gNB(s) selected by the measurement results.

[0218] - 3. If the candidate target ground-gNB(s) allows HO, it can send a response to it to the (source) ground-gNB(B).

[0219] - 4. (source) Ground-gNB(B) can perform CHO-related settings on the ground UE. For example, (source) Ground-gNB(B) can provide the ground UE with an RRCReconfiguration message containing CHO settings for CHO trigger conditions, etc.

[0220] - 5. A ground UE that has received the configuration for the CHO can send an RRCReconfigurationComplete message to the (source) ground-gNB(B).

[0221] - 6. The ground-gNB(B) can provide an Early status transfer message to candidate target gNB(s).

[0222] - 7. When the ground UE satisfies a specific set HO triggering condition, it can complete the CHO handover procedure by performing RACH to the target gNB(A).

[0223] - 8. The target ground-gNB (A) can provide a message related to the success of the HO with the ground UE to the source ground-gNB (B).

[0224] - 9. The source ground-gNB (B) can provide an SN status transfer message to the target ground-gNB (A).

[0225] - 10. The source ground-gNB(B) can send a message related to HO cancellation to the remaining candidate target gNBs, excluding the target ground-gNB(A) from the candidate target gNB(s).

[0226] The CHO procedure according to the method of Case 1-3 and / or Case 1-4 can receive settings related to HO for several candidate target ground-gNBs in advance and trigger HO based on measurements taken by the ground UE. In this case, compared to the general HO procedure, it has the advantage of being able to determine HO based on currently measured values.

[0227] 2. Scenario 2

[0228] (1) Case 2-1

[0229] Referring to Fig. 19, a ground UE connected to gNB(A) can perform HO to the satellite-gNB(B).

[0230] - 1. (source) A ground UE connected to the ground-gNB(A) can perform measurement reporting to the (source) ground-gNB(A).

[0231] - 2. (source) Ground-gNB(A) can determine the HO based on the measured report value and send an HO request message to (target) satellite-gNB(B).

[0232] - 3. The ground-gNB(A) can receive a response message from the satellite-gNB(B) that it allows HO.

[0233] - 4. The ground-gNB(A) can send an RRCReconfiguration message containing an HO command to the ground UE.

[0234] - 5. The ground-gNB (A) can send an SN status Transfer message to the satellite-gNB (B).

[0235] - 6. After receiving an RRCReconfiguration message containing an HO command, the ground UE can perform an HO to the target satellite-gNB(B) and complete the HO procedure by transmitting an RCReconfigurationComplete message to the ground-gNB(A).

[0236] - 7. The UE is connected to the target satellite-gNB(B), and 8. the target satellite-gNB(B) can send a UE context release message to the source ground-gNB(A).

[0237] (1) Case 2-2

[0238] Referring to Fig. 20, a ground UE connected to the satellite-gNB (B) can perform HO to the ground-gNB (A).

[0239] - 1. A ground UE connected to the satellite-gNB(B) can perform a measurement report to the satellite-gNB(B) when a measurement report is triggered.

[0240] - 2. The satellite-gNB(B) can determine the HO based on the above measurement report, determine the target ground-gNB(A), and send an HO request message to the target ground-gNB(A).

[0241] - 3. The satellite-gNB(B) can receive a response from the target ground-gNB(A) that it allows HO.

[0242] - 4. (source) The satellite-gNB(B) can send an RRCReconfiguration message containing an HO command to the ground UE.

[0243] - 5. (source) The satellite-gNB(B) can send an SN status transfer message to the target ground-gNB(A).

[0244] - 6. After receiving an RRCReconfiguration message containing an HO command, the ground UE can perform an HO to the Target ground-gNB (A) and transmit an RRCReconfigurationComplete message to the satellite-gNB (B) to complete the HO procedure.

[0245] - 7. The UE is connected to the Target ground-gNB (A), and 8. The Target ground-gNB (A) can send a UE context release message to the source satellite-gNB (B).

[0246] In Cases 2-1 and 2-2, similar to the HO case in Scenario 1 described above, the time required for a ground UE to transmit a measured value to the satellite-gNB, for the satellite-gNB to request an HO from the ground-gNB and receive admission (and / or for a ground-gNB to request an HO from the satellite-gNB and receive admission) may be significantly longer than in the case of a standard HO. In this case, the measured value from the ground UE may be out-of-date, and determining the HO based on it may be unsuitable for achieving good performance. Therefore, a conditional HO (CHO) may be a more appropriate operation for HOs used in satellite communication. This will be explained in detail below in Cases 2-3 and 2-4.

[0247] (3) Case 2-3

[0248] Referring to Fig. 21, a ground UE connected to a ground-gNB (A) can perform a CHO procedure with a satellite-gNB (B).

[0249] - 1. When a measurement report is triggered, the ground UE can report the measurement value to (source) ground-gNB(A).

[0250] - 2. (source) The ground-gNB(A) can send an HO request message to the candidate satellite-gNB(s) based on the above measurement report.

[0251] - 3. (source) The ground-gNB(A) can receive admission for HO ( / HO Request ACK) from the candidate satellite-gNB(s).

[0252] - 4. The (source) ground-gNB(A) that receives this can send an RRCReconfiguration message to the ground UE for CHO-related configuration for multiple candidate satellite-gNB(s).

[0253] - 5. If the ground UE receives the configuration related to the CHO, it can send RRCReconfigurationComplete to the (source) ground-gNB(A).

[0254] - 6. A ground-gNB(A) may provide an Early status transfer message to a candidate target satellite-gNB(s). Here, the Early status transfer message may include information about the RLC and PDCP layer status of the ground UE.

[0255] - 7. When a conditional HO (CHO) is triggered based on a set value, the UE can perform an HO by selecting one target satellite-gNB from among the candidate target satellite-gNB(s) and performing the RACH procedure.

[0256] - 8. The target satellite-gNB(B) can provide a message related to the success of the HO with the ground UE to the ground-gNB(A).

[0257] - 9. The ground-gNB (A) can provide SN status transfer messages to the target satellite-gNB (B).

[0258] - 10. Ground-gNB(A) can send a message related to HO cancellation to the remaining candidate target satellite-gNBs, excluding the target satellite-gNB(B) from the candidate target satellite-gNB(s).

[0259] (4) Case 2-4

[0260] Referring to Fig. 22, a ground UE connected to the satellite-gNB (B) can perform a CHO procedure with the ground-gNB (A).

[0261] - 1. When a measurement report is triggered, the ground UE performs a measurement report to the satellite-gNB(B).

[0262] - 2. The satellite-gNB(B) can determine the CHO and send an HO request message to the candidate target ground-gNB(s) selected by the measurement results.

[0263] - 3. If the candidate target ground-gNB(s) allows HO, it can transmit a response to the satellite-gNB(B).

[0264] - 4. The satellite-gNB(B) can perform CHO-related settings on the ground UE. For example, the satellite-gNB(B) can provide the ground UE with an RRCReconfiguration message containing CHO settings for CHO trigger conditions, etc.

[0265] - 5. A ground UE that has received the configuration for the CHO can send an RRCReconfigurationComplete message to the satellite-gNB(B).

[0266] - 6. The satellite-gNB(B) can provide an Early status transfer message to candidate target ground-gNB(s).

[0267] - 7. When the ground UE satisfies a specific set HO triggering condition, it performs a RACH procedure to a selected target ground-gNB(A) among the candidate target ground-gNB(s), and can complete a CHO procedure with the target ground-gNB(A) through the RACH procedure.

[0268] - 8. The target ground-gNB (A) can provide a message related to the success of the HO with the ground UE to the satellite-gNB (B).

[0269] - 9. The satellite-gNB(B) can provide SN status transfer messages to the target ground-gNB(A).

[0270] - 10. Satellite-gNB(B) can send a message related to HO cancellation to the remaining candidate target ground-gNBs, excluding the target ground-gNB(A) from the candidate target ground-gNB(s).

[0271] Figures 23 and 24 are drawings for explaining the coverage of NTN.

[0272] NTN (Non-terrestrial Networks) operation typically refers to an operation that performs communication via a satellite. However, NTN operation is not limited to communication via a satellite. For example, NTN operation may also include communication via HAPs (high altitude platforms). In certain scenarios (3GPP), NTN operation is defined as operation via a satellite. For example, in certain scenarios, configuration information related to the NTN or NTN cell may be provided through system information (SIB19). Specifically, SIB19 may be a system information block containing essential satellite assistance information for NTN (Non-Terrestrial Network) access. This information is used by the UE to connect to and maintain a connection with a cell in an NTN environment and may include detailed NTN-related configuration and timing information such as ntn-Config, t-Service, referenceLocation, movingReferenceLocation, distanceThresh, epochTime, ntn-RS-TimingInfo, ssb-TimeOffset, and satellite ephemeris (see TS38.331). The above system information may be information broadcast directly from the NTN cell. The following description assumes that NTN operations are operations via satellite.

[0273] Cell coverage using satellites as an NTN operation can be defined into three types: coverage based on an Earth fixed cell (deployed by GEO satellite) as shown in FIG. 23 (a), coverage based on a Quasi-Earth fixed cell (deployed by LEO satellite) as shown in FIG. 23 (b), and coverage based on an Earth moving cell (deployed by LEO satellite).

[0274] Among the three types mentioned above, in the case of a quasi-Earth fixed cell, the coverage of the cell (or NTN, NTN cell) may change due to satellite movement. For example, as illustrated in FIG. 23 (b), the coverage of the NTN at the first time (t1) may shift / change to the coverage of the NTN at the second time (t2). In this case, from the perspective of the UE, the cell coverage changes suddenly. Therefore, a method may be required to ensure that measurements can be started / triggered at the UE connected to the NTN (and / or the UE camped on the serving cell) before the cell coverage changes. As described above, t-Service has been introduced as a value for starting / triggering such measurements. T-Service may be the time indicating that the serving cell (or serving NTN cell) will no longer operate in the serving area (e.g., the time when the coverage of the serving cell moves from a specific geographic area to another geographic area). T-Service is a value provided only for NTN or NTN cells based on quasi-earth fixed cells, and can be included in SIB19 and broadcast. If a t-Service value exists in SIB19, t-Service indicates that operation as a serving cell in the corresponding area will cease after the time elapsed according to t-Service.

[0275] Meanwhile, the distance between the satellite (or NTN cell) and the UE may be significantly longer than the distance between the existing gNB and the UE. Therefore, the signal received by the UE via the satellite may have a lower signal strength compared to the signal received from the ground gNB. As such, the relatively low signal strength may have characteristics as shown in FIG. 24 (b) in the region corresponding to the edge of the cell coverage.

[0276] For example, as illustrated in FIG. 24 (b), when the UE is located at the edge of the cell coverage of the NTN cell, the signal strength may not differ significantly from the signal strength when the UE is located at the center of the cell coverage of the NTN cell (e.g., the rate of signal strength reduction within the cell coverage is low). Therefore, the method of triggering a measurement report based solely on the signal strength value of the UE, as in conventional TN, may not be sufficient or appropriate for NTN.

[0277] Considering the signal attenuation characteristics of NTN, measurement reporting can be triggered in a location-based manner within NTN. For example, 'referenceLocation' and 'distanceThresh' values ​​can be set for the UE via SIB19, dedicated RRC messages, etc. The UE may perform cell reselection or trigger measurement reporting based on the 'referenceLocation' and / or 'distanceThresh' values. In this case, the referenceLocation value represents a specific point (geographic location value) within the coverage of the serving cell, and distanceThresh may represent a value for the threshold distance at which location-based measurement begins / is triggered. Specifically, measurement action / measurement reporting may be triggered if the UE is located at a location further away than distanceThresh relative to the referenceLocation value. For example, a measurement report may be triggered if the distance between a specific geographic location based on the referenceLocation value and the UE's own location is greater than or equal to distanceThresh. For example, a measurement report ( / measurement initiation) may be triggered when the degree of signal strength reduction or the absolute signal strength value is less than a defined threshold strength (e.g., in the case of a measurement report for a ground gNB), but in the case of an NTN, a measurement-related action may be triggered when the UE is located farther away than a set distance (e.g., distanceThresh) relative to the referenceLocation.

[0278] Below, the in-order delivery method on the RLC layer is explained in detail, taking into account the aforementioned NTN system.

[0279] Figures 25 and 26 are diagrams illustrating a method of transferring SDU from an RLC layer to an upper layer.

[0280] Referring to FIG. 25, the RLC layer can deliver Service Data Units (SDUs) to an upper layer (e.g., PDCP) based on a sequential delivery method. Here, the sequential delivery method may be a method in which the RLC layer delivers SDUs by ordering them according to the data order when delivering them to an upper layer. In this case, the RLC layer delivers incoming SDUs to the upper layer by sorting them according to the order (e.g., the sequence number (SN) assigned to the data), but when the 't-Reordering' timer expires, SDUs that do not match the assigned SN may also be delivered to the upper layer. For example, referring to FIG. 25, SDU5 may be delivered to the upper layer after the 't-Reordering' timer expires, even if SDU4 has not yet been delivered to the upper layer. Meanwhile, an SDU received by the RLC layer after the 't-Reordering' timer expires may be removed without being delivered to the upper layer, even though it was received, because it was received after the timer expired. For example, as illustrated in Fig. 25, SDU4 delivered / received to the RLC layer after the 't-Reordering' timer expires may be discarded without being delivered to the upper layer.

[0281] Referring to FIG. 26, the RLC layer can deliver SDUs to the upper layer without sorting them according to data order based on an out-of-order delivery method. For example, when an out-of-order delivery method is applied, the RLC layer can deliver the received SDUs directly to the upper layer without sorting them according to data order. For example, as shown in FIG. 26, even if the RLC layer receives SDU5 after receiving SDU1 and SDU2, it can deliver the received SDU5 directly to the upper layer. Meanwhile, SDUs received after the 't-Reordering' timer expires may be discarded without being delivered to the upper layer.

[0282] It can be assumed that the reason SDUs received after the 't-Reordering' timer expires are not forwarded to the upper layer is that even if the received SDUs were sent to the upper layer, they would no longer be usable by the upper layer. This 't-Reordering' value may be related to the service's QoS requirement (e.g., latency).

[0283] The t-Reordering value defined in the current scenario (3GPP TS38.331) is set as shown in Table 5 below, and the currently set value can be set to a long value of up to 3 seconds.

[0284] - t-Reordering ENUMERATED {ms0, ms1, ms2, ms4, ms5, ms8, ms10, ms15, ms20, ms30, ms40,ms50, ms60, ms80, ms100, ms120, ms140, ms160, ms180, ms200, ms220, ms240, ms260, ms280, ms300, ms500, ms750, ms1000, ms1250, ms1500, ms1750, ms2000, ms2250, ms2500, ms2750, ms3000, spare28, spare27, spare26, spare25, spare24, spare23, spare22, spare21, spare20, spare19, spare18, spare17, spare16, spare15, spare14, spare13, spare12, spare11, spare10, spare09, spare08, spare07, spare06, spare05, spare04, spare03, spare02, spare01}

[0285] This 't-Reordering' value is set by the upper layer to the AS layer and can be configured according to the UE's implementation.

[0286] Meanwhile, as described above, in the case of NTN communication (NTN scenario), the transmission distance is longer compared to TN communication, so a larger propagation delay may be required than in the case of TN. When a single gNB or different gNBs are connected via TN and NTN, the gNB or UE receives a message through the NTN path after passing through a much larger propagation delay compared to TN. For example, when a single gNB or different gNBs are connected via TN and NTN, it may be a case of CA (in the case of existing CA operation, it means the case where one UE is connected to one gNB) or DC (in the case of existing DC operation, it means the case where one UE is connected to different gNBs).

[0287] In the following, it is assumed that the TN path and the NTN path are connected to the same gNB, and that the same data / data packets can be transmitted to each of the TN path and the NTN path respectively to improve reliability (e.g., via a configured split bearer). Based on this assumption, the following describes in detail a method to omit ACK / NACK transmission via the NTN path when data is received first via the TN path, taking into account the long propagation delay of the NTN path.

[0288] Method to omit HARQ ACK and NACK in TN-NTN dual-connection structure

[0289] FIGS. 27 and 28 are diagrams illustrating a method for transmitting and receiving HARQ ACK information when the UE and gNB are connected via a TN path and an NTN path.

[0290] When a gNB and a UE are connected via an NTN path and a TN path (e.g., a TN-NTN duplex structure), a large difference in propagation delay may occur between the NTN path and the TN path. For example, as illustrated in FIG. 27, the UE or gNB may transmit and receive the same data packet through both the TN path and the NTN path to improve reliability. In this case, the difference between the time it takes for the same data packet (or Transport Block; TB) to reach the gNB (or UE) via the satellite (e.g., the NTN path) and the time it takes to reach the gNB (or UE) via the TN path can be significant.

[0291] In this case, due to the propagation delay of NTN, a data packet identical to the data packet on the TN path may be received through the NTN path after a NACK for the data packet on the TN path has been transmitted through the TN path. Additionally, even after an ACK has been transmitted through the TN path, a data packet identical to the data packet on the TN path may be received through the NTN path after the propagation delay of NTN has elapsed. If the same data is received through the NTN path after an ACK has been transmitted through the TN path (or if reception fails), sending an ACK (or a NACK in the case of reception failure) through the NTN path may be a waste of resources.

[0292] In the following, a method or condition is described in detail regarding a case where a gNB (or UE) transmits the same data through an NTN path and a TN path, and data is received through the NTN path after the transmission of ACK information for data in the TN path due to NTN propagation delay, in which the UE omits the transmission of ACK information for data in the NTN path (e.g., HARQ ACK information).

[0293] 1. Cases where HARQ ACK / NACK is transmitted / omitted at the PHYSICAL layer (Layer 1)

[0294] Referring to FIG. 28, the UE (gNB in ​​the case of UL) can receive the same data packet (or TB, PDSCH) through the NTN path after transmitting an ACK (e.g., HARQ Process #1 in slot x) for the data packet (or TB, PDSCH) received through the TN path. In this case, the UE may not transmit an ACK / NACK for the data packet received through the NTN path through the NTN path. This is because transmitting information regarding the ACK / NACK through the NTN path in this case would consume unnecessary resources and require an additional propagation time of a long duration. To perform this operation of omitting ACK information for data reception on the NTN path, the receiving side (e.g., UE in the case of DL) must be able to determine whether the data packet received through the TN path and the data packet received through the NTN path are identical data packets that have been duplicated from each other.

[0295] For example, when ACK / NACK is transmitted at the physical layer, values ​​such as SN (Sequence number) are not included, so a method may be required to distinguish whether data packets transmitted through different paths are the same data packet. For example, the ACK / NACK value is determined by the MAC entity, and since the physical layer cannot verify the SN value, etc., from the information regarding the ACK / NACK transmitted from the MAC entity, a method may be required to determine whether the data packet received on the TN path and the data packet received on the NTN path are the same through other methods.

[0296] To this end, additional information may be required so that the physical layer of the receiver (e.g., the terminal in the case of DL) can know that the data packet received through the TN path and the data packet received through the NTN path are the same data packet (or, additional information is required so that the physical layer can know that the data packets received through the TN and NTN paths are the same data packet). This is because the current structure of the transmitted / received data packets of the physical layer cannot distinguish whether the same data has been received.

[0297] Accordingly, in order to (directly) determine at the physical layer of the receiver or receiving end whether a data packet received in the TN path and a data packet received in the NTN path are the same, at least one of the following information elements (hereinafter referred to as control information) may be required. The following information may be information included in DCI (Downlink Control Information). Or, it may be information included in DCI that schedules the reception of data packets for the TN path (or schedules the reception of data packets for the NTN path).

[0298] - HARQ Process Number ID: The number (and / or ID) of a HARQ process may be limited. Assuming a structure where the same data transmitted from the physical layer through different paths (TN path or NTN path) is shared up to the PDCP / RLC / MAC layer (similar to existing CA), the same data can naturally have the same HARQ process ID (where the HARQ process number / ID is a value determined at the MAC layer). In this case, the physical layer may have different entities for the TN path and the NTN path. For example, if the first data transmitted on the TN path and the second data transmitted on the NTN path are the same data, it can be assumed that the HARQ process ID associated with the first data and the HARQ process ID associated with the second data are identical.

[0299] - Timing information for PDSCH reception: The UE must be able to know the timing information (e.g., reception timing information) for receiving PDSCH from another path associated with the HARQ process ID for the received data. For example, the receiver or UE (or the UE's PHY layer) must know the value of the HARQ process ID of the currently received data / data packet through the TN path, and must know at what PDSCH timing on the NTN path the same data as the data / data packet on the TN path reaches, so that the physical layer of the receiver or terminal can determine whether the data packet transmitted through the TN path and the data packet transmitted through the NTN path are the same packet. For example, the above DCI (or, the DCI that schedules the PDSCH transmitted in the TN path) may include reception timing information regarding when the same data associated with the HARQ process ID of the data received in the TN path is received through the NTN path, and the physical layer of the terminal may clearly identify / determine the data / data packet of the NTN path associated with the value of the HARQ process ID of the data / data packet received through the TN path based on the reception timing information included in the above DCI.

[0300] - Information on which frequency (or component carrier or transmission path) the same data packet can be transmitted: for example, if a data packet is received via a TN path (or a component carrier associated with TN), information may be required that the same data packet can be received via an NTN path (or a component carrier associated with NTN). Assuming that a UE can receive data / data packets via multiple frequency bands (or multiple transmission paths or multiple component carriers) (e.g., CA), information on which frequency band among the multiple frequency bands the same data packet can be (additionally) received by the UE needs to be provided (via the DCI).

[0301] - Duplication indication: In addition to the information elements described above, information may be required to identify whether the received data packet has been duplicated. For example, if the control information includes a duplication indication, the UE can use the other information elements described above to identify / specify which identical data packet is received through a different path.

[0302] If the receiving end (UE), based on at least one information element (or control information) described above, transmits an ACK for a data packet received through the TN and then determines / finds that a data packet received through the NTN path is the same data packet as the data packet in the TN path, the receiving end may not transmit any signal regardless of the ACK / NACK of the data packet received through the NTN path.

[0303] When the transmitting end (gNB) receives an ACK for a data packet transmitted through the TN path, it may not expect to receive an ACK / NACK for a data packet transmitted through the NTN path (e.g., a data packet identical to the data packet transmitted through the TN path). For instance, since the transmitting end knew that the data packet was successfully transmitted through the TN path by receiving the ACK information for the data packet, it may not perform retransmission of the data packet through the NTN path even if an ACK / NACK was not received for the data packet transmitted through the NTN path.

[0304] 2. Cases where HARQ ACK / NACK is transmitted / omitted at the MAC( / RLC / PDCP) layer

[0305] ACK / NACK may be a value determined at the MAC ( / RLC / PDCP) layer. In this case as well, similar to what was explained in "1", it must be possible to determine whether data packets received through different paths are identical. Unlike the physical layer, received data packets can be decoded starting from the MAC layer. Therefore, when data packets are received through two different paths (TN path / NTN path), the MAC (or RLC / PDCP) layer / entity can determine whether the same data was received through a different path based on whether the decoding result or the decoding value is identical. Additionally, since the SN (Sequence Number) is used in the packet header of each layer at the RLC / PDCP layer / entity, the RLC / PDCP layer / entity can use the aforementioned SN value to determine whether data received through a specific path is identical to data received through another path within a certain period of time. However, in the case of NTN, the long propagation delay time may exceed the above-mentioned certain time (e.g., a time range that can be expressed as SN) (e.g., when different data packets with the same SN value are transmitted within the propagation delay), and in this case, it may be difficult to distinguish whether the data is duplicated based solely on the SN value.

[0306] The MAC( / RLC / PDCP) layer / entity can determine whether the same data packet was transmitted via different paths (TN-NTN) by decoding the received data packet. For example, if the decoding result of a data packet received via the NTN path is an ACK after an ACK for a data packet received via the TN path has already been transmitted, the MAC( / RLC / PDCP) layer / entity does not need to transmit an ACK to the NTN path. This is because an ACK for the same data packet has already been transmitted via the TN path. However, if the decoding result of a data packet received via the NTN path is a NACK, there is no guarantee that the data packet is the same as the data already received via the TN path (e.g., because decoding is impossible). Therefore, the MAC( / RLC / PDCP) layer / entity or the UE must transmit a NACK via the NTN path.

[0307] Alternatively, a 'duplicate indication' may be included in the MAC header. For example, it may be necessary to include an indication in the MAC header regarding whether the received data packet may be received duplicately through different paths, such as the NTN path and the TN path. This is because, based on the above indication, the MAC ( / RLC / PDCP) layer / entity at the receiving end can determine, based on decoding, whether it is necessary to determine / determine whether the data packets received from different paths are the same data packet. Additionally, information regarding which frequency the message is transmitted through may also be additionally required. For example, since the MAC ( / RLC / PDCP) layer / entity may additionally require information regarding which path the data packet was received through among the TN path and the NTN path, the MAC header may include information (or indication information) regarding the path through which the data packet was transmitted.

[0308] The MAC ( / RLC / PDCP) layer of the transmitter (gNB in ​​the case of DL) that receives an ACK through the TN path does not expect to receive an ACK / NACK through the NTN path. For example, if the transmitter sends the same data packet through both the TN path and the NTN path, and receives an ACK for the data packet from the TN path, the transmitter may expect that no ACK or NACK will be received through the NTN path. For example, if an ACK is received through the TN path, the transmitter may not retransmit the data packet even if no ACK for the same data packet is received through the NTN path.

[0309] The proposed method described above suggests a method for a receiver (UE in the case of DL) to distinguish whether the same packet has been transmitted through the two paths when a gNB and a UE are dually connected via the TN path and the NTN path. For example, if the receiver transmits an ACK through one of the TN path and the NTN path but receives the same packet through the other path, it may omit the transmission of an ACK / NACK for the data packet from the other path. Alternatively, depending on the case, the receiver may omit only the transmission of an ACK for the data packet from the other path. Since resources consumed in ACK / NACK transmission can be saved through this operation, there may be an advantage in terms of the efficient use of resources.

[0310] FIG. 29 is a diagram illustrating a method for a UE to transmit HARQ ACK information for data received through a first transmission path and a second transmission path.

[0311] The above UE forms a first transmission path and a second transmission path with a base station (gNB) and can transmit and receive data / signals / messages using the first transmission path and the second transmission path. The first transmission path and the second transmission path may be established based on split bearer or based on Carrier Aggregation (CA). In this case, the UE can receive a first data or a first PDSCH (e.g., a PDSCH containing the first data) through the first transmission path and a second data or a second PDSCH (e.g., a PDSCH containing the second data) through the second transmission path from the base station. Here, the first transmission path may be a TN path (e.g., a path directly connected between the base station and the UE), and the second transmission path may be an NTN path (e.g., a path connected between the base station and the UE through an NTN or NTN cell). In this case, as described in the section "Method for omitting HARQ ACK and NACK in TN-NTN dual connection structure," when the same data or the same data packet is transmitted through the dual path, the transmission of HARQ ACK information for the NTN path may be omitted.

[0312] Specifically, referring to FIG. 29, the UE can receive configuration information for a first transmission path and a second transmission path from a base station (S291). As described above, the configuration information may include information for setting the first transmission path and the second transmission path based on a split bearer, or information for setting CA for the first transmission path and the second transmission path.

[0313] Next, the UE can receive a first PDSCH (downlink physical shared channel) through the first transmission path (S293). For example, the UE can receive a first DCI that schedules the first PDSCH for the first transmission path, and can receive the first PDSCH through the first transmission path based on the first DCI. As described above, the first PDSCH may include a first data packet, a first TB, or a first data. As described above, the base station may transmit the same data / data packet / TB through the first transmission path and the second transmission path, respectively, to improve reliability.

[0314] Next, the UE can transmit first HARQ ACK (Hybrid Automatic Repeat reQuest Acknowledgement) information for the first PDSCH (S295). For example, the UE can transmit first HARQ ACK information including a bit value of ACK when decoding the first PDSCH is successful, or transmit first HARQ ACK information including a bit value of NACK when decoding the first PDSCH is unsuccessful.

[0315] Next, the UE can receive the second PDSCH through the second transmission path (S297). For example, the UE can receive a second DCI that schedules the second PDSCH for the second transmission path, and can receive the second PDSCH through the second transmission path based on the second DCI. As described above, when the second transmission path is an NTN path, even if the second PDSCH and the first PDSCH are transmitted from the base station at the same or similar timing, the second PDSCH may be received later than the first PDSCH by the propagation delay time due to the propagation delay of the NTN path. For example, even if the second PDSCH and the first PDSCH are transmitted simultaneously, the second PDSCH may be received after the transmission of the first HARQ ACK information due to the propagation delay of the NTN.

[0316] Next, the UE can determine / determine whether the second PDSCH contains data corresponding to the first PDSCH when the above predetermined conditions are satisfied (S299). Here, the predetermined conditions may be satisfied when the second PDSCH is received after the transmission of the first HARQ ACK and the second transmission path is related to a non-terrestrial network (NTN). For example, even if the base station simultaneously transmits the first PDSCH via the first transmission path and the second PDSCH via the second transmission path for the same data packet, the UE may receive the second PDSCH only after transmitting the HARQ ACK information for the first PDSCH. At this time, if the second PDSCH contains the same data packet as the first PDSCH, unnecessary HARQ resources (e.g., PUCCH resources) may be wasted when the UE also transmits the HARQ ACK information for the second PDSCH. Accordingly, in order to prevent the transmission of unnecessary HARQ ACK information when the above predetermined conditions are satisfied, the UE may perform a procedure / operation to determine whether the second PDSCH contains the same data / data packet / TB (hereinafter, data) as the first PDSCH when the above predetermined conditions are satisfied.

[0317] In this regard, the base station may (pre-)transmit control information to the UE, which enables the UE's PHY layer to directly determine whether the second PDSCH contains the same data as the first PDSCH. For example, the base station may additionally include the control information in the DCI that schedules the first PDSCH, or provide the control information through a separate DCI. As described above, the control information may include at least one of reception timing information related to the second transmission path associated with the HARQ process ID (identifier) ​​for the first PDSCH, first instruction information regarding the transmission of the same data through the first transmission path and the second transmission path, or second instruction information regarding whether duplicate data is transmitted. In this case, the UE (or the UE's PHY layer) can determine whether the second PDSCH contains the same data as the first PDSCH based on the control information without performing decoding of the data contained in the second PDSCH. For example, if the control information includes the reception timing information, the UE may determine / consider that the second PDSCH contains data identical or corresponding to the first PDSCH if the second PDSCH has the same HARQ process ID as the first PDSCH and is received at a timing according to the reception timing information. Alternatively, if the control information includes the reception timing information and the first instruction information (or second instruction information), the UE may determine / consider that the second PDSCH contains data identical or corresponding to the first PDSCH based on the fact that the second PDSCH was received at a timing corresponding to the reception timing information.

[0318] Alternatively, if the control information includes the first instruction information or the second instruction information, and the second PDSCH is received within a time interval after the transmission of the first HARQ ACK information, it may be determined / considered that the second PDSCH contains data identical or corresponding to the first PDSCH. Here, the predetermined time interval may be determined based on the propagation delay time associated with the NTN occurring in the second transmission path. For example, if the control information includes the first instruction information or the second instruction information without including the reception timing information, and the second PDSCH is received within the predetermined time interval, the UE may consider / consider that the same data according to the control information was received after the transmission of the first HARQ ACK information due to the propagation delay of the NTN from the time of transmission of the first HARQ ACK information.

[0319] In this way, if it is determined that the second PDSCH contains data identical to the data of the first PDSCH, the UE may omit / skip the transmission of the second HARQ ACK information for the second PDSCH.

[0320] Meanwhile, if it is determined that the second PDSCH does not contain data identical to or corresponding to the data of the first PDSCH, the UE may transmit second HARQ ACK information for the second PDSCH. For example, if the second PDSCH is received after the predetermined time interval, is not received at the time corresponding to the reception timing information, or has a HARQ process ID different from the first PDSCH, the UE may determine that the second PDSCH contains data distinct from the first PDSCH and transmit second HARQ ACK information for the second PDSCH.

[0321] FIG. 30 is a diagram illustrating a method for a base station to receive HARQ ACK information for data received through a first transmission path and a second transmission path.

[0322] A base station (gNB) forms a first transmission path and a second transmission path with a UE, and can transmit and receive data / signals / messages using the first transmission path and the second transmission path. The first transmission path and the second transmission path may be established based on split bearer or based on Carrier Aggregation (CA). In this case, the base station may transmit a first data or a first PDSCH (e.g., a PDSCH containing the first data) through the first transmission path and a second data or a second PDSCH (e.g., a PDSCH containing the second data) through the second transmission path to the UE. Here, the first transmission path may be a TN path (e.g., a directly connected path between the base station and the UE), and the second transmission path may be an NTN path (e.g., a path connecting the base station and the UE through an NTN or NTN cell). In this case, as described in the section "Method for omitting HARQ ACK and NACK in TN-NTN dual connection structure," when the same data or the same data packet is transmitted through the dual path, the transmission of HARQ ACK information for the NTN path may be omitted.

[0323] Specifically, referring to FIG. 30, the base station may transmit configuration information for the first transmission path and the second transmission path to the UE (S301). As described above, the configuration information may include information for setting the first transmission path and the second transmission path based on a split bearer, or information for setting CA for the first transmission path and the second transmission path.

[0324] Next, the base station may transmit a first PDSCH (downlink physical shared channel) to the UE through the first transmission path (S303). For example, the base station may transmit a first DCI that schedules the first PDSCH for the first transmission path, and may transmit the first PDSCH through the first transmission path based on the first DCI. As described above, the first PDSCH may include a first data packet, a first TB, or a first data. As described above, the base station may transmit the same data / data packet / TB through the first transmission path and the second transmission path, respectively, to improve reliability.

[0325] Next, the base station can transmit the second PDSCH to the UE through the second transmission path (S305). As described above, when the second transmission path is an NTN path, even if the second PDSCH and the first PDSCH are transmitted at the same or similar timing, the second PDSCH may be received by the UE with a delay of the propagation delay time compared to the first PDSCH due to the propagation delay of the NTN path. For example, even if the second PDSCH and the first PDSCH are transmitted simultaneously, the second PDSCH may be received after the transmission of the first HARQ ACK information.

[0326] Next, the base station may receive first HARQ ACK (Hybrid Automatic Repeat reQuest Acknowledgement) information for the first PDSCH from the UE (S307). For example, the base station may receive first HARQ ACK information including a bit value of ACK for success of decoding the first PDSCH from the UE, or first HARQ ACK information including a bit value of NACK for failure of decoding the first PDSCH.

[0327] Meanwhile, the base station may not perform retransmission for the second PDSCH even if the second HARQ ACK information for the second PDSCH of the second transmission path is not received from the UE when the second transmission path is associated with a non-terrestrial network (NTN) and the first PDSCH and the second PDSCH contain the same data (e.g., when the same data is transmitted through the first transmission path and the second transmission path). Alternatively, the base station may not expect that HARQ ACK information will not be received in the second transmission path when it receives an ACK through the first transmission path, or it may not perform retransmission of the second PDSCH through the second transmission path even if HARQ ACK information is not received in the second transmission path.

[0328] As described above, the base station may provide the UE with control information in advance that can determine the data identity between the first PDSCH and the second PDSCH prior to decoding the second PDSCH being performed at the UE. As described above, the control information may include at least one of reception timing information related to the second transmission path associated with the HARQ process ID (identifier) ​​for the first PDSCH, first instruction information regarding the transmission of identical data through the first transmission path and the second transmission path, or second instruction information regarding whether duplicate data is transmitted.

[0329] Meanwhile, if the UE determines that the second PDSCH does not contain data identical to or corresponding to the data of the first PDSCH, the base station may receive second HARQ ACK information for the second PDSCH from the UE. For example, if the second PDSCH is received after the predetermined time interval, is not received at the time corresponding to the reception timing information, or has a HARQ process ID different from the first PDSCH, the base station may receive second HARQ ACK information for the second PDSCH from the UE.

[0330] In this way, the proposed invention can effectively prevent redundant transmission of HARQ ACK information for the same data due to the difference in propagation delay time between the NTN path and the TN path, thereby minimizing unnecessary use of HARQ feedback resources.

[0331] Alternatively, the proposed invention can determine whether to omit the transmission of HARQ ACK information for the data in the NTN path more quickly and efficiently by determining the identity between the data in the TN path and the data in the NTN path before decoding is performed on the data received in the NTN path.

[0332] Example of a communication system to which the invention is applied

[0333] Although not limited thereto, the various descriptions, functions, procedures, proposals, methods, and / or flowcharts of the invention disclosed in this document may be applied to various fields requiring wireless communication / connection (e.g., 5G) between devices.

[0334] Examples are provided in more detail below with reference to the drawings. In the following drawings and descriptions, the same reference numerals may represent the same or corresponding hardware blocks, software blocks, or function blocks unless otherwise described.

[0335] FIG. 31 illustrates a communication system to which the present invention is applied.

[0336] Referring to FIG. 31, the communication system (1) to which the present invention applies includes a wireless device, a base station, and a network. Here, the wireless device refers to a device that performs communication using wireless access technology (e.g., 5G NR (New RAT), LTE (Long Term Evolution)) and may be referred to as a communication / wireless / 5G device. Although not limited thereto, the wireless device may include a robot (100a), a vehicle (100b-1, 100b-2), an XR (eXtended Reality) device (100c), a hand-held device (100d), a home appliance (100e), an IoT (Internet of Thing) device (100f), and an AI device / server (400). For example, the vehicle may include a vehicle equipped with wireless communication functions, an autonomous vehicle, a vehicle capable of performing inter-vehicle communication, etc. Here, the vehicle may include an Unmanned Aerial Vehicle (UAV) (e.g., a drone). XR devices include AR (Augmented Reality) / VR (Virtual Reality) / MR (Mixed Reality) devices and can be implemented in the form of HMDs (Head-Mounted Devices), HUDs (Head-Up Displays) equipped in vehicles, televisions, smartphones, computers, wearable devices, home appliances, digital signage, vehicles, robots, etc. Portable devices may include smartphones, smartpads, wearable devices (e.g., smartwatches, smart glasses), computers (e.g., laptops, etc.). Home appliances may include TVs, refrigerators, washing machines, etc. IoT devices may include sensors, smart meters, etc. For example, base stations and networks may be implemented as wireless devices, and a specific wireless device (200a) may operate as a base station / network node to other wireless devices.

[0337] Wireless devices (100a to 100f) can be connected to a network (300) through a base station (200). Artificial Intelligence (AI) technology may be applied to the wireless devices (100a to 100f), and the wireless devices (100a to 100f) can be connected to an AI server (400) through the network (300). The network (300) can be configured using a 3G network, a 4G (e.g., LTE) network, or a 5G (e.g., NR) network. The wireless devices (100a to 100f) may communicate with each other through the base station (200) / network (300), but they may also communicate directly (e.g., sidelink communication) without going through the base station / network. For example, vehicles (100b-1, 100b-2) can communicate directly (e.g., V2V (Vehicle to Vehicle) / V2X (Vehicle to everything) communication). Also, IoT devices (e.g., sensors) can communicate directly with other IoT devices (e.g., sensors) or other wireless devices (100a to 100f).

[0338] Wireless communication / connection (150a, 150b, 150c) can be established between wireless devices (100a~100f) / base station (200) and base station (200) / base station (200). Here, wireless communication / connection can be achieved through various wireless access technologies (e.g., 5G NR), such as uplink / downlink communication (150a), sidelink communication (150b) (or D2D communication), and inter-base station communication (150c) (e.g., relay, IAB (Integrated Access Backhaul)). Through wireless communication / connection (150a, 150b, 150c), wireless devices and base stations / wireless devices, and base stations and base stations can transmit / receive wireless signals to / from each other. For example, wireless communication / connection (150a, 150b, 150c) can transmit / receive signals through various physical channels. To this end, based on various proposals of the present invention, at least some of the following may be performed: various configuration information setting processes for transmitting / receiving wireless signals, various signal processing processes (e.g., channel encoding / decoding, modulation / demodulation, resource mapping / demapping, etc.), resource allocation processes, etc.

[0339] Example of a wireless device to which the present invention is applied

[0340] FIG. 32 illustrates a wireless device that can be applied to the present invention.

[0341] Referring to FIG. 32, the first wireless device (100) and the second wireless device (200) can transmit and receive wireless signals through various wireless access technologies (e.g., LTE, NR). Here, {the first wireless device (100), the second wireless device (200)} may correspond to {wireless device (100x), base station (200)} and / or {wireless device (100x), wireless device (100x)} of FIG. 31.

[0342] The first wireless device (100) includes one or more processors (102) and one or more memories (104), and may additionally include one or more transceivers (106) and / or one or more antennas (108). The processor (102) controls the memory (104) and / or transceivers (106) and may be configured to implement the descriptions, functions, procedures, proposals, methods and / or flowcharts of operation disclosed in this document. For example, the processor (102) may process information within the memory (104) to generate a first information / signal and then transmit a wireless signal containing the first information / signal through the transceiver (106). Additionally, the processor (102) may receive a wireless signal containing a second information / signal through the transceiver (106) and then store information obtained from the signal processing of the second information / signal in the memory (104). The memory (104) may be connected to the processor (102) and may store various information related to the operation of the processor (102). For example, the memory (104) may store software code containing instructions for performing some or all of the processes controlled by the processor (102) or for performing the descriptions, functions, procedures, proposals, methods, and / or operation sequence diagrams disclosed in this document. Here, the processor (102) and the memory (104) may be part of a communication modem / circuit / chipset designed to implement wireless communication technology (e.g., LTE, NR). The transceiver (106) may be connected to the processor (102) and may transmit and / or receive wireless signals through one or more antennas (108). The transceiver (106) may include a transmitter and / or receiver. The transceiver (106) may be combined with an RF (Radio Frequency) unit. In the present invention, the wireless device may refer to a communication modem / circuit / chipset.

[0343] Specifically, the first wireless device or UE (100) may include a processor (102) connected to a transceiver (106) and a memory (104). The memory (104) may include at least one program capable of performing operations related to the embodiments proposed in the section “Method for omitting HARQ ACK and NACK in a TN-NTN dual-link structure”. The operations include receiving configuration information for a first transmission path and a second transmission path; receiving a first PDSCH (downlink physical shared channel) through the first transmission path; transmitting a first HARQ ACK (Hybrid Automatic Repeat reQuest Acknowledgement) information for the first PDSCH; and receiving a second PDSCH through the second transmission path. and (i) the second PDSCH is received after the transmission of the first HARQ ACK, and (ii) the second transmission path is associated with a non-terrestrial network (NTN), and the second PDSCH is determined to include data corresponding to the first PDSCH, and the transmission of the second HARQ ACK information for the second PDSCH may be omitted based on the determination that the second PDSCH includes data corresponding to the first PDSCH.

[0344] Alternatively, a processing device may be configured including a processor (102) and a memory (104) that control the UE (100). In this case, the processing device may include at least one processor; and at least one memory connected to the at least one processor and storing instructions that perform operations when executed by the at least one processor. The operations include receiving configuration information for a first transmission path and a second transmission path; receiving a first PDSCH (downlink physical shared channel) through the first transmission path; transmitting a first HARQ ACK (Hybrid Automatic Repeat reQuest Acknowledgement) information for the first PDSCH; and receiving a second PDSCH through the second transmission path. and (i) the second PDSCH is received after the transmission of the first HARQ ACK, and (ii) the second transmission path is associated with a non-terrestrial network (NTN), and the second PDSCH is determined to include data corresponding to the first PDSCH, and the transmission of the second HARQ ACK information for the second PDSCH may be omitted based on the determination that the second PDSCH includes data corresponding to the first PDSCH.

[0345] The second wireless device (200) includes one or more processors (202) and one or more memories (204), and may additionally include one or more transceivers (206) and / or one or more antennas (208). The processor (202) controls the memory (204) and / or transceivers (206) and may be configured to implement the descriptions, functions, procedures, proposals, methods and / or operation sequences disclosed in this document. For example, the processor (202) may process information within the memory (204) to generate a third information / signal and then transmit a wireless signal containing the third information / signal through the transceiver (206). Additionally, the processor (202) may receive a wireless signal containing a fourth information / signal through the transceiver (206) and then store information obtained from the signal processing of the fourth information / signal in the memory (204). The memory (204) may be connected to the processor (202) and may store various information related to the operation of the processor (202). For example, the memory (204) may store software code containing instructions for performing some or all of the processes controlled by the processor (202) or for performing the descriptions, functions, procedures, proposals, methods, and / or operation sequence diagrams disclosed in this document. Here, the processor (202) and the memory (204) may be part of a communication modem / circuit / chip designed to implement wireless communication technology (e.g., LTE, NR). The transceiver (206) may be connected to the processor (202) and may transmit and / or receive wireless signals through one or more antennas (208). The transceiver (206) may include a transmitter and / or receiver. The transceiver (206) may be interchangeable with an RF unit. In the present invention, the wireless device may refer to a communication modem / circuit / chip.

[0346] Specifically, the second wireless device or base station (200) may include a processor (202) and a memory (204) connected to a transceiver or RF transceiver (206). The memory (204) may include at least one program capable of performing operations related to the embodiments proposed in the section “Method for omitting HARQ ACK, NACK in TN-NTN dual connection structure”. The above operations include transmitting configuration information for a first transmission path and a second transmission path to a UE (User Equipment), transmitting a first PDSCH (downlink physical shared channel) to the UE through the first transmission path, transmitting a second PDSCH to the UE through the second transmission path, and receiving a first HARQ ACK (Hybrid Automatic Repeat reQuest Acknowledgement) information for the first PDSCH from the UE, and based on (i) the second transmission path is associated with a non-terrestrial network (NTN) and (ii) the first PDSCH and the second PDSCH contain the same data, the processor may not perform retransmission of the second PDSCH through the second transmission path even if the second HARQ ACK information for the second PDSCH is not received.

[0347] Hereinafter, hardware elements of the wireless device (100, 200) will be described in more detail. Although not limited thereto, one or more protocol layers may be implemented by one or more processors (102, 202). For example, one or more processors (102, 202) may implement one or more layers (e.g., functional layers such as PHY, MAC, RLC, PDCP, RRC, SDAP). One or more processors (102, 202) may generate one or more Protocol Data Units (PDUs) and / or Service Data Units (SDUs) according to the descriptions, functions, procedures, proposals, methods, and / or flowcharts of operation disclosed in this document. One or more processors (102, 202) may generate messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or flowcharts of operation disclosed in this document. One or more processors (102, 202) may generate a signal (e.g., baseband signal) containing a PDU, SDU, message, control information, data, or information according to the functions, procedures, proposals, and / or methods disclosed in this document and provide it to one or more transceivers (106, 206). One or more processors (102, 202) may receive a signal (e.g., baseband signal) from one or more transceivers (106, 206) and may obtain a PDU, SDU, message, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or flowcharts disclosed in this document.

[0348] One or more processors (102, 202) may be referred to as a controller, microcontroller, microprocessor, or microcomputer. One or more processors (102, 202) may be implemented by hardware, firmware, software, or a combination thereof. For example, one or more Application Specific Integrated Circuits (ASICs), one or more Digital Signal Processors (DSPs), one or more Digital Signal Processing Devices (DSPDs), one or more Programmable Logic Devices (PLDs), or one or more Field Programmable Gate Arrays (FPGAs) may be included in one or more processors (102, 202). The descriptions, functions, procedures, proposals, methods, and / or flowcharts disclosed in this document may be implemented using firmware or software, and the firmware or software may be implemented to include modules, procedures, functions, etc. Firmware or software configured to perform the descriptions, functions, procedures, proposals, methods, and / or operation sequences disclosed in this document may be contained in one or more processors (102, 202) or stored in one or more memories (104, 204) and driven by one or more processors (102, 202). The descriptions, functions, procedures, proposals, methods, and / or operation sequences disclosed in this document may be implemented using firmware or software in the form of code, instructions, and / or sets of instructions.

[0349] One or more memories (104, 204) may be connected to one or more processors (102, 202) and may store various forms of data, signals, messages, information, programs, code, instructions, and / or commands. One or more memories (104, 204) may be composed of ROM, RAM, EPROM, flash memory, hard drive, registers, cache memory, computer read storage media, and / or combinations thereof. One or more memories (104, 204) may be located inside and / or outside of one or more processors (102, 202). Additionally, one or more memories (104, 204) may be connected to one or more processors (102, 202) through various technologies such as wired or wireless connections.

[0350] One or more transceivers (106, 206) may transmit user data, control information, wireless signals / channels, etc., as mentioned in the methods and / or operation flowcharts, etc., of this document to one or more other devices. One or more transceivers (106, 206) may receive user data, control information, wireless signals / channels, etc., as mentioned in the descriptions, functions, procedures, proposals, methods and / or operation flowcharts, etc., disclosed in this document from one or more other devices. For example, one or more transceivers (106, 206) may be connected to one or more processors (102, 202) and may transmit and receive wireless signals. For example, one or more processors (102, 202) may control one or more transceivers (106, 206) to transmit user data, control information, or wireless signals to one or more other devices. Additionally, one or more processors (102, 202) may control one or more transceivers (106, 206) to receive user data, control information, or wireless signals from one or more other devices. Additionally, one or more transceivers (106, 206) may be connected to one or more antennas (108, 208), and one or more transceivers (106, 206) may be configured to transmit and receive user data, control information, wireless signals / channels, etc., as described in the descriptions, functions, procedures, proposals, methods, and / or flowcharts of operation disclosed in this document through one or more antennas (108, 208). In this document, one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). One or more transceivers (106, 206) can convert the received wireless signal / channel, etc. from an RF band signal to a baseband signal in order to process the received user data, control information, wireless signal / channel, etc. using one or more processors (102, 202).One or more transceivers (106, 206) can convert user data, control information, wireless signals / channels, etc. processed using one or more processors (102, 202) from baseband signals to RF band signals. To this end, one or more transceivers (106, 206) may include (analog) oscillators and / or filters.

[0351] Examples of wireless device applications to which the present invention is applied

[0352] FIG. 33 illustrates another example of a wireless device to which the present invention applies. The wireless device may be implemented in various forms depending on the use-example / service (see FIG. 31).

[0353] Referring to FIG. 33, the wireless device (100, 200) corresponds to the wireless device (100, 200) of FIG. 32 and may be composed of various elements, components, units / parts, and / or modules. For example, the wireless device (100, 200) may include a communication unit (110), a control unit (120), a memory unit (130), and additional elements (140). The communication unit may include a communication circuit (112) and transceiver(s) (114). For example, the communication circuit (112) may include one or more processors (102, 202) and / or one or more memories (104, 204) of FIG. 33. For example, the transceiver(s) (114) may include one or more transceivers (106, 206) and / or one or more antennas (108, 208) of FIG. 32. The control unit (120) is electrically connected to the communication unit (110), the memory unit (130), and additional elements (140) and controls the general operation of the wireless device. For example, the control unit (120) may control the electrical / mechanical operation of the wireless device based on a program / code / command / information stored in the memory unit (130). Additionally, the control unit (120) may transmit information stored in the memory unit (130) to an external (e.g., another communication device) via a wireless / wired interface through the communication unit (110), or store information received from an external (e.g., another communication device) via a wireless / wired interface through the communication unit (110) in the memory unit (130).

[0354] The additional element (140) can be configured in various ways depending on the type of wireless device. For example, the additional element (140) may include at least one of a power unit / battery, an input / output unit (I / O unit), a driving unit, and a computing unit. Although not limited thereto, the wireless device may be implemented in the form of a robot (Fig. 31, 100a), a vehicle (Fig. 31, 100b-1, 100b-2), an XR device (Fig. 31, 100c), a portable device (Fig. 31, 100d), a home appliance (Fig. 31, 100e), an IoT device (Fig. 31, 100f), a digital broadcasting terminal, a hologram device, a public safety device, an MTC device, a medical device, a fintech device (or financial device), a security device, a climate / environment device, an AI server / device (Fig. 31, 400), a base station (Fig. 31, 200), a network node, etc. Wireless devices can be used in a movable or fixed location depending on the use—e.g., service.

[0355] In FIG. 33, various elements, components, units / parts, and / or modules within the wireless device (100, 200) may be entirely interconnected via a wired interface, or at least a portion may be wirelessly connected via a communication unit (110). For example, within the wireless device (100, 200), the control unit (120) and the communication unit (110) may be wired, and the control unit (120) and the first unit (e.g., 130, 140) may be wirelessly connected via the communication unit (110). Additionally, each element, component, unit / part, and / or module within the wireless device (100, 200) may include one or more additional elements. For example, the control unit (120) may be composed of one or more sets of processors. For example, the control unit (120) may be composed of a set of a communication control processor, an application processor, an Electronic Control Unit (ECU), a graphics processing processor, a memory control processor, etc. As another example, the memory unit (130) may be composed of RAM (Random Access Memory), DRAM (Dynamic RAM), ROM (Read Only Memory), flash memory, volatile memory, non-volatile memory and / or a combination thereof.

[0356] Examples of vehicles or autonomous vehicles to which the present invention is applied

[0357] FIG. 34 illustrates a vehicle or autonomous vehicle to which the present invention applies. The vehicle or autonomous vehicle may be implemented as a mobile robot, a vehicle, a train, an aerial vehicle (AV), a ship, etc.

[0358] Referring to FIG. 34, a vehicle or autonomous vehicle (100) may include an antenna unit (108), a communication unit (110), a control unit (120), a driving unit (140a), a power supply unit (140b), a sensor unit (140c), and an autonomous driving unit (140d). The antenna unit (108) may be configured as part of the communication unit (110). Blocks 110 / 130 / 140a to 140d each correspond to blocks 110 / 130 / 140 of FIG. 33.

[0359] The communication unit (110) can transmit and receive signals (e.g., data, control signals, etc.) with external devices such as other vehicles, base stations (e.g., base stations, roadside base stations (Roadside units), etc.), and servers. The control unit (120) can perform various operations by controlling elements of the vehicle or autonomous vehicle (100). The control unit (120) may include an Electronic Control Unit (ECU). The driving unit (140a) can drive the vehicle or autonomous vehicle (100) on the ground. The driving unit (140a) may include an engine, motor, power train, wheels, brakes, steering device, etc. The power supply unit (140b) supplies power to the vehicle or autonomous vehicle (100) and may include wired / wireless charging circuits, batteries, etc. The sensor unit (140c) can obtain vehicle status, surrounding environment information, user information, etc. The sensor unit (140c) may include an IMU (inertial measurement unit) sensor, a collision sensor, a wheel sensor, a speed sensor, an inclination sensor, a weight detection sensor, a heading sensor, a position module, a vehicle forward / reverse sensor, a battery sensor, a fuel sensor, a tire sensor, a steering sensor, a temperature sensor, a humidity sensor, an ultrasonic sensor, an illuminance sensor, a pedal position sensor, etc. The autonomous driving unit (140d) may implement technologies such as maintaining the driving lane, technologies for automatically adjusting speed such as adaptive cruise control, technologies for automatically driving along a predetermined path, and technologies for automatically setting a path and driving when a destination is set.

[0360] For example, the communication unit (110) can receive map data, traffic information data, etc. from an external server. The autonomous driving unit (140d) can generate an autonomous driving path and a driving plan based on the acquired data. The control unit (120) can control the drive unit (140a) so that the vehicle or the autonomous vehicle (100) moves along the autonomous driving path according to the driving plan (e.g., speed / direction control). During autonomous driving, the communication unit (110) can acquire the latest traffic information data from an external server non-periodically and can acquire surrounding traffic information data from surrounding vehicles. Additionally, during autonomous driving, the sensor unit (140c) can acquire vehicle status and surrounding environment information. The autonomous driving unit (140d) can update the autonomous driving path and the driving plan based on the newly acquired data / information. The communication unit (110) can transmit information regarding the vehicle location, autonomous driving path, driving plan, etc. to an external server. An external server can predict traffic information data in advance using AI technology, etc., based on information collected from vehicles or autonomous vehicles, and can provide the predicted traffic information data to vehicles or autonomous vehicles.

[0361] Here, the wireless communication technology implemented in the wireless device (XXX, YYY) of this specification may include LTE, NR, and 6G, as well as Narrowband Internet of Things for low-power communication. For example, NB-IoT technology may be an example of LPWAN (Low Power Wide Area Network) technology and may be implemented according to standards such as LTE Cat NB1 and / or LTE Cat NB2, but is not limited to the names mentioned above. Additionally, or generally, the wireless communication technology implemented in the wireless device (XXX, YYY) of this specification may perform communication based on LTE-M technology. For example, LTE-M technology may be an example of LPWAN technology and may be referred to by various names such as eMTC (enhanced Machine Type Communication). For example, LTE-M technology may be implemented in at least one of various standards such as 1) LTE CAT 0, 2) LTE Cat M1, 3) LTE Cat M2, 4) LTE non-BL (non-Bandwidth Limited), 5) LTE-MTC, 6) LTE Machine Type Communication, and / or 7) LTE M, and is not limited to the names mentioned above. Additionally or generally, wireless communication technology implemented in the wireless device (XXX, YYY) of this specification may include at least one of ZigBee, Bluetooth, and Low Power Wide Area Network (LPWAN) with consideration for low-power communication, and is not limited to the names mentioned above. As an example, ZigBee technology can create personal area networks (PANs) related to small / low-power digital communication based on various standards such as IEEE 802.15.4, and may be referred to by various names.

[0362] The embodiments described above are combinations of the components and features of the present invention in a specific form. Each component or feature should be considered optional unless otherwise explicitly stated. Each component or feature may be implemented in a form not combined with other components or features. Additionally, it is possible to construct embodiments of the present invention by combining some components and / or features. The order of operations described in the embodiments of the present invention may be changed. Some components or features of one embodiment may be included in another embodiment, or may be replaced with corresponding components or features of another embodiment. It is obvious that embodiments may be constructed by combining claims that do not have an explicit citation relationship in the claims, or that new claims may be included by amendment after filing.

[0363] In this document, embodiments of the present invention are described primarily with a focus on the signal transmission and reception relationship between a terminal and a base station. This transmission and reception relationship is extended in the same or similar manner to signal transmission and reception between a terminal and a relay or between a base station and a relay. Specific operations described in this document as being performed by a base station may, in some cases, be performed by an upper node. That is, it is self-evident that various operations performed for communication with a terminal in a network consisting of multiple network nodes including a base station may be performed by the base station or other network nodes other than the base station. The base station may be replaced by terms such as fixed station, Node B, eNode B (eNB), and access point. Additionally, the terminal may be replaced by terms such as User Equipment (UE), Mobile Station (MS), and Mobile Subscriber Station (MSS).

[0364] Embodiments according to the present invention may be implemented by various means, for example, hardware, firmware, software, or a combination thereof. In the case of implementation by hardware, one embodiment of the present invention may be implemented by one or more ASICs (application specific integrated circuits), DSPs (digital signal processors), DSPDs (digital signal processing devices), PLDs (programmable logic devices), FPGAs (field programmable gate arrays), processors, controllers, microcontrollers, microprocessors, etc.

[0365] In the case of implementation by firmware or software, an embodiment of the present invention may be implemented in the form of a module, procedure, function, etc., that performs the functions or operations described above. Software code may be stored in a memory unit and executed by a processor. The memory unit may be located inside or outside the processor and may exchange data with the processor by various means already known.

[0366] It is obvious to those skilled in the art that the present invention may be embodied in other specific forms without departing from the features of the invention. Accordingly, the foregoing detailed description should not be interpreted restrictively in all respects but should be considered exemplary. The scope of the invention shall be determined by a reasonable interpretation of the appended claims, and all modifications within the equivalent scope of the invention are included within the scope of the invention.

[0367] The embodiments of the present invention as described above can be applied to various mobile communication systems.

Claims

1. In a method using UE (user equipment), A step of receiving configuration information for a first transmission path and a second transmission path; A step of receiving a first PDSCH (downlink physical shared channel) through the first transmission path; A step of transmitting first HARQ ACK (Hybrid Automatic Repeat reQuest Acknowledgement) information for the first PDSCH; and The method includes the step of receiving a second PDSCH through the second transmission path, (i) the second PDSCH is received after the transmission of the first HARQ ACK, and (ii) based on the fact that the second transmission path is associated with a non-terrestrial network (NTN), the UE determines whether the second PDSCH includes data corresponding to the first PDSCH, and A method in which the transmission of second HARQ ACK information for the second PDSCH is omitted based on the determination that the second PDSCH contains data corresponding to the first PDSCH.

2. In Paragraph 1, A method further comprising the step of receiving control information including reception timing information associated with the second transmission path associated with the HARQ process ID (identifier) ​​for the first PDSCH.

3. In Paragraph 2, A method in which, based on the fact that the second PDSCH having the above HARQ process ID is received at a timing corresponding to the reception timing information, the second PDSCH is determined to contain data corresponding to the first PDSCH.

4. In Paragraph 2, The above control information further includes first instruction information regarding transmission of the same data through the first transmission path and the second transmission path, or second instruction information regarding whether to transmit duplicate data.

5. In Paragraph 2, A method in which the above control information is received via DCI (downlink control information).

6. In Paragraph 1, Based on the fact that the second PDSCH is received within a predefined time from the reception of the first PDSCH after the transmission of the first HARQ ACK, the UE determines whether the second PDSCH includes data corresponding to the first PDSCH, and The above-mentioned predefined time is a method defined based on the propagation delay time associated with the NTN.

7. In Paragraph 1, Based on the fact that the second HARQ ACK information for the second PDSCH is a NACK (Negative ACK), it is determined that the second PDSCH does not contain data corresponding to the first PDSCH, and A method in which the second HARQ ACK information is transmitted based on the determination that the second PDSCH does not contain data corresponding to the first PDSCH.

8. In Paragraph 1, The above setting information includes information for setting the first transmission path and the second transmission path for CA (Carrier Aggregation), and A method in which the first transmission path is a transmission path associated with a TN (terrestrial network) and the second transmission path is a transmission path associated with an NTN.

9. In at least one non-transient computer-readable recording medium, Includes instructions that perform operations when executed by at least one processor, The above operations are, Receive configuration information for the first transmission path and the second transmission path; Receiving the first PDSCH (downlink physical shared channel) through the first transmission path; Transmit first HARQ ACK (Hybrid Automatic Repeat reQuest Acknowledgement) information for the first PDSCH above; Receiving the second PDSCH through the second transmission path; and (i) the second PDSCH is received after the transmission of the first HARQ ACK, and (ii) based on the fact that the second transmission path is associated with a non-terrestrial network (NTN), the method includes determining whether the second PDSCH contains data corresponding to the first PDSCH. At least one non-transient computer-readable recording medium in which the transmission of a second HARQ ACK information for the second PDSCH is omitted based on the determination that the second PDSCH contains data corresponding to the first PDSCH.

10. Regarding UE (user equipment), RF (Radio Frequency) transceiver; and It includes a processor connected to the above RF transceiver, and The processor controls the RF transceiver to receive configuration information for a first transmission path and a second transmission path, receives a first PDSCH (downlink physical shared channel) through the first transmission path, transmits a first HARQ ACK (Hybrid Automatic Repeat reQuest Acknowledgement) information for the first PDSCH, and receives a second PDSCH through the second transmission path, wherein (i) the second PDSCH is received after the transmission of the first HARQ ACK, and (ii) the processor determines whether the second PDSCH includes data corresponding to the first PDSCH based on whether the second transmission path is associated with a non-terrestrial network (NTN). A UE in which the transmission of the second HARQ ACK information for the second PDSCH is omitted based on the determination that the second PDSCH contains data corresponding to the first PDSCH.

11. In Paragraph 10, A UE configured to further receive control information including reception timing information associated with the second transmission path associated with the HARQ process ID (identifier) ​​for the first PDSCH.

12. In Paragraph 10, A UE in which, based on the fact that the second PDSCH having the above HARQ process ID is received at a timing corresponding to the reception timing information, the second PDSCH is determined to contain data corresponding to the first PDSCH.

13. In a processing device for controlling UE (user equipment), At least one processor; and It includes at least one memory that stores instructions connected to the above at least one processor and performing operations when executed by the at least one processor, The above operations are, Receive configuration information for the first transmission path and the second transmission path; Receiving the first PDSCH (downlink physical shared channel) through the first transmission path; Transmit first HARQ ACK (Hybrid Automatic Repeat reQuest Acknowledgement) information for the first PDSCH above; Receiving the second PDSCH through the second transmission path; and (i) the second PDSCH is received after the transmission of the first HARQ ACK, and (ii) based on the fact that the second transmission path is associated with a non-terrestrial network (NTN), the method includes determining whether the second PDSCH contains data corresponding to the first PDSCH. A processing device in which the transmission of second HARQ ACK information for the second PDSCH is omitted based on the determination that the second PDSCH contains data corresponding to the first PDSCH.

14. In the method using a base station, A step of transmitting configuration information for the first transmission path and the second transmission path to the UE (User Equipment); A step of transmitting a first PDSCH (downlink physical shared channel) to the UE through the first transmission path; The step of transmitting a second PDSCH to the UE through the second transmission path; and The method includes the step of receiving first HARQ ACK (Hybrid Automatic Repeat reQuest Acknowledgement) information for the first PDSCH from the UE, (i) the second transmission path is associated with a non-terrestrial network (NTN), and (ii) based on the fact that the first PDSCH and the second PDSCH contain the same data, the base station does not perform retransmission of the second PDSCH through the second transmission path even if the second HARQ ACK information for the second PDSCH is not received.

15. Regarding base stations, RF (Radio Frequency) transceiver; and It includes a processor connected to the above RF transceiver, and The processor controls the RF transceiver to transmit configuration information for a first transmission path and a second transmission path to a UE (User Equipment), transmits a first PDSCH (downlink physical shared channel) to the UE through the first transmission path, transmits a second PDSCH to the UE through the second transmission path, and receives a first HARQ ACK (Hybrid Automatic Repeat reQuest Acknowledgement) information for the first PDSCH from the UE. (i) the second transmission path is associated with a non-terrestrial network (NTN), and (ii) based on the fact that the first PDSCH and the second PDSCH contain the same data, the processor does not perform retransmission of the second PDSCH through the second transmission path even if the second HARQ ACK information for the second PDSCH is not received.

Images