Method for performing communication in wireless communication system and device therefor

Abstract

A device, according to various embodiments, may: form a first link with a UE; form a second link connecting to the UE through a NTN-related satellite; and transmit a SSB for acquiring synchronization of the second link.

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 base station according to one aspect comprises the steps of: forming a first link with a UE (User Equipment); forming a second link connected to the UE through a satellite associated with a non-terrestrial network (NTN); and transmitting a Synchronization Signal Block (SSB) for acquiring synchronization of the second link, wherein the SSB includes a Primary Synchronization Signal (PSS), a Secondary Synchronization Signal (SSS), and a Physical Broadcast Channel (PBCH), and the SSB for acquiring synchronization of the second link may be transmitted through the first link rather than the second link.

[0018] Alternatively, the SSB may be transmitted with a delay based on the propagation delay associated with the second link.

[0019] Alternatively, the SSB may be delayed and transmitted based on the value obtained by subtracting the propagation delay associated with the first link from the propagation delay associated with the second link.

[0020] Alternatively, the propagation delay associated with the second link may be a value estimated based on the distance between the base station and the satellite.

[0021] Alternatively, the PBCH of the SSB may include instruction information to indicate that it is a synchronization signal associated with the second link.

[0022] Alternatively, the SSB may include a virtual cell ID (identifier) ​​for identifying that it is a synchronization signal associated with the second link.

[0023] Alternatively, the virtual cell ID may be determined based on the sum of predefined values ​​of the cell ID (identifier) ​​of the base station.

[0024] Alternatively, it may further include the step of transmitting a measurement signal for measuring the quality of the second link through the second link.

[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 forming a first link with a UE (User Equipment); forming a second link connected to said UE via a satellite associated with a NTN (non-terrestrial network); and transmitting a Synchronization Signal Block (SSB) for acquiring synchronization of said second link, said SSB including a Primary Synchronization Signal (PSS), a Secondary Synchronization Signal (SSS), and a Physical Broadcast Channel (PBCH), said SSB for acquiring synchronization of said second link may be transmitted through said first link rather than said second link.

[0026] According to another aspect, a base station comprises a Radio Frequency (RF) transceiver; and a processor connected to the RF transceiver, wherein the processor controls the RF transceiver to form a first link with a User Equipment (UE), forms a second link connected to the UE via a satellite associated with a non-terrestrial network (NTN), and transmits a Synchronization Signal Block (SSB) for acquiring synchronization of the second link, wherein the SSB includes a Primary Synchronization Signal (PSS), a Secondary Synchronization Signal (SSS), and a Physical Broadcast Channel (PBCH), and wherein the SSB for acquiring synchronization of the second link may be transmitted through the first link rather than the second link.

[0027] According to another aspect, a processing device controlling a base station 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 forming a first link with a UE (User Equipment); forming a second link connected to the UE via a satellite associated with a non-terrestrial network (NTN); and transmitting a Synchronization Signal Block (SSB) for acquiring synchronization of the second link, wherein the SSB includes a Primary Synchronization Signal (PSS), a Secondary Synchronization Signal (SSS), and a Physical Broadcast Channel (PBCH), and the SSB for acquiring synchronization of the second link may be transmitted through the first link rather than the second link.

[0028] A method by a UE (User Equipment) according to another aspect comprises the steps of: forming a first link with a base station; and forming a second link connected to the base station through a non-terrestrial network (NTN), wherein the synchronization of the second link is obtained based on a Synchronization Signal Block (SSB) received through the first link rather than the second link, and the SSB may include a Primary Synchronization Signal (PSS), a Secondary Synchronization Signal (SSS), and a Physical Broadcast Channel (PBCH).

[0029] According to another aspect, a UE (User Equipment) comprises an RF (Radio Frequency) transceiver; and a processor connected to the RF transceiver, wherein the processor controls the RF transceiver to form a first link with a base station and forms a second link connected to the base station via a non-terrestrial network (NTN), and the synchronization of the second link is obtained based on a Synchronization Signal Block (SSB) received through the first link rather than the second link, and the SSB may include a Primary Synchronization Signal (PSS), a Secondary Synchronization Signal (SSS), and a Physical Broadcast Channel (PBCH).

[0030] According to one embodiment, signals can be transmitted and received more accurately and efficiently in a wireless communication system. For example, by causing a base station to delay-transmit an SSB through a TN to reflect the propagation delay associated with the NTN path, even if a UE uses an SSB received through a first link, it can more accurately obtain a timing reference corresponding to a second link, thereby improving the synchronization accuracy and synchronization maintenance reliability of the NTN link.

[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] FIG. 1 is a drawing for explaining the comparison between V2X communication based on RAT prior to NR and V2X communication based on NR. The drawings attached to this specification are intended to provide an understanding of the present invention, to show various embodiments of the present invention, and to explain the principles of the present invention together with the description in the specification.

[0034] Figure 1 is a diagram illustrating a comparison between V2X communication based on RAT prior to NR and V2X communication based on NR.

[0035] Figure 2 shows the structure of an LTE system.

[0036] Figure 3 shows the structure of the NR system.

[0037] Figure 4 shows the structure of a wireless frame of NR.

[0038] Figure 5 shows the slot structure of an NR frame.

[0039] FIG. 6 shows a communication structure that can be provided in a 6G system according to one embodiment of the present disclosure.

[0040] FIG. 7 shows an electromagnetic spectrum according to one embodiment of the present disclosure.

[0041] Figure 8 shows the radio protocol architecture for SL communication.

[0042] Figure 9 shows a terminal performing V2X or SL communication.

[0043] Figure 10 shows a resource unit for V2X or SL communication.

[0044] FIG. 11 shows an example of a BWP according to one embodiment of the present disclosure.

[0045] 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.

[0046] FIG. 13 shows an example of a general NTN scenario based on a transparent payload or a regenerated payload according to one embodiment.

[0047] Figures 14 and 15 are drawings for explaining the coverage of NTN.

[0048] Figures 16 and 17 are diagrams illustrating TN and NTN multiple connection scenarios.

[0049] Figures 18 and 19 are diagrams illustrating the operation of a UE that has formed an NTN-TN multiple connection.

[0050] FIG. 20 is a diagram illustrating a method for a base station to transmit a signal for obtaining synchronization for the NTN path and / or a reference signal for quality measurement to a UE that has formed a TN path and an NTN path.

[0051] FIG. 21 is a diagram illustrating a method for obtaining synchronization for the NTN path among the TN path and NTN path formed by the UE with the base station.

[0052] FIG. 22 illustrates a communication system to which the present invention is applied.

[0053] FIG. 23 illustrates a wireless device that can be applied to the present invention.

[0054] FIG. 24 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. 25 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 simply 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 a primary signal and obtain synchronization. For example, a terminal may use S-PSS and S-SSS to obtain detailed synchronization and detect a 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-SSSS, 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 be transmitted with a bandwidth corresponding to the 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 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] BWP is point A, offset from point A ( ) and bandwidth( It can be set by ). 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 in that carrier) is aligned. For example, offset may be the PRB interval between the lowest subcarrier in a given numerology and point A. For example, 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-SSS 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-SSSS, 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 be transmitted with a bandwidth corresponding to the 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] Figures 14 and 15 are drawings for explaining the coverage of NTN.

[0169] 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.

[0170] 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. 14 (a), coverage based on a Quasi-Earth fixed cell (deployed by LEO satellite) as shown in FIG. 14 (b), and coverage based on an Earth moving cell (deployed by LEO satellite) as shown in FIG. 14 (c).

[0171] 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. 14 (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.

[0172] 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. 15 (b) in the region corresponding to the edge of the cell coverage.

[0173] For example, as illustrated in FIG. 15 (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.

[0174] 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.

[0175] Figures 16 and 17 are diagrams illustrating TN and NTN multiple connection scenarios.

[0176] FIG. 16 (a) illustrates an exemplary case of multi-connectivity including a transparent NTN-based NG-RAN and a cellular NG-RAN, FIG. 16 (b) illustrates an exemplary case of multi-connectivity between two transparent NTN-based NG-RANs, and FIG. 16 (c) illustrates an exemplary case of multi-connectivity between two regenerative NTN-based NG-RANs (including a substrate-mounted gNB).

[0177] Generally, a terrestrial UE in an RRC IDLE / INACTIVE state can receive TAC (Tracking Area Code) and PLMN (Public Land Mobile Network) values ​​broadcast from its cell via the SIB (System Information Block). If the received TAC and PLMN values ​​do not exist in its TAI (Tracking Area Identity, TAC + PLMN) list or TAC list, the terrestrial UE can initiate / execute the TA Update (Tracking Area Update, TAU) procedure. The Network (NW) can perform a registration update using the TAI value received from the UE and can transmit a new TAI list to the UE. Assuming that the RRC IDLE / INACTIVE UE exists within an area belonging to the TAI list, the Network can broadcast the paging message to the TAC area configured for the UE when it needs to send a paging message to the said RRC IDLE / INACTIVE UE. A single TAC value can be used per cell. For example, a single cell broadcasts only one TAC value, which can be a geographically determined value. UEs in an RRC IDLE / INACTIVE state connected to an NTN (Non-Terrestrial Network) must also perform a TAU operation to receive paging messages. If an NTN moving cell broadcasts a single TAC value per cell, UEs located at the cell boundary must execute the TAU procedure whenever they receive a new TAC value. This can be burdensome for UEs in a fast-moving NTN environment.

[0178] Specifically, referring to FIG. 17, TAU fluctuation can occur in the case of a UE in a fixed position, as the TAC value continues to change, such as when a UE belonging to TAC2 at time T1 belongs to TAC1 at time T2 and belongs to another TAC2 at time T3. In this regard, NTN can use a locally fixed TAC value (or TA value), just as TN. For example, a locally determined TAC (layout) value may already exist at the location where the satellite passes, and a satellite passing through a specific geographical area can broadcast the TAC value of said specific geographical area. Since the satellite's cell coverage covers a wide area, a single satellite cell (or NTN cell) can broadcast multiple TAC values.

[0179] Additionally, in an NTN moving cell environment, considering that the satellite is constantly moving, the TAC list may also include time bounds applicable to each TAC value. In this case, the UE can determine whether to execute the TAU procedure by judging that the set TAC value is valid only within the time interval corresponding to the aforementioned time bounds.

[0180] How to reduce the power of a disabled link in NTN-TN multi-connection

[0181] Figures 18 and 19 are diagrams illustrating the operation of a UE that has formed an NTN-TN multiple connection.

[0182] To date, there has not been sufficient discussion in the relevant field regarding the specific operation of a UE that simultaneously possesses two links (or paths)—a TN (Terrestrial Network) and an NTN (Non-Terrestrial Network). However, in order to improve throughput and reliability, communication can be performed by forming an NTN connection even while located within TN coverage. For example, an NTN link can be maintained in parallel to expand transmission opportunities even when the link quality provided by the TN momentarily deteriorates or traffic is congested.

[0183] The proposed method is based on the premise that a single UE, existing within TN cell coverage and possessing a TN path as illustrated in FIG. 18, additionally possesses an NTN path. Here, "path" may refer to a wireless access / transmission path between the UE and the network (e.g., a wireless bearer for each link, a physical / hierarchical connection, or an independent communication path identified by link configuration). In the following description, it is assumed that the UE can activate or deactivate the NTN path as needed (e.g., according to service requirements, link quality, traffic conditions, power conditions, policy settings, etc.). And / or, it is assumed that the TN and NTN are connected to the same gNB (gNodeB) / base station. Here, "connected to the same gNB / base station" may mean a configuration in which the TN and NTN connections are managed / controlled by the same base station entity from a network perspective. The power reduction monitoring plan proposed below can be implemented under these premises.

[0184] A method for measuring the signal strength of the NTN path (e.g., a value corresponding to received power or reception quality) can be performed by measuring the signal strength of the DMRS (Demodulation Reference Signal), SSB (Synchronization Signal Block), PSS (Primary Synchronization Signal), and / or SSS (Secondary Synchronization Signal). In order to measure the DMRS signal strength, the UE must be able to continuously track, maintain, and match the downlink synchronization of the NTN path. This is because, after the UE matches the downlink synchronization, it can measure the DMRS signal strength based on the matched synchronization. For example, if the synchronization reference point / frame / slot / symbol boundary is unclear, it is difficult to accurately determine the location of the DMRS resource, and as a result, the accuracy or feasibility of signal strength measurement may be degraded.

[0185] Therefore, a gNB or base station may need to transmit an SSB signal transmitted via the NTN path (path A+B+C in FIG. 18) via the TN path (path D in FIG. 18). For example, the gNB or base station may forward the SSB to be transmitted via the NTN path to the TN link, thereby enabling the UE to support signal strength measurement or rapid activation of the NTN path while relieving the synchronous tracking burden of the NTN path.

[0186] The gNB can determine the distance to the gateway (A) and the distance between the gateway and the satellite (B). For example, the gNB-gateway segment may be distance / latency information provided by a management system or pre-configured as a ground backhaul / transmission network segment, and the gateway-satellite segment may be calculated based on the satellite orbit / link configuration or provided as parameters that the base station can reference. In this case, information related to the satellite's orbit may be included in SIB19. For example, the satellite's orbital elements / ephemeris or parameters required for calculating the satellite position may be included in SIB19. The satellite's coverage can cover a much wider area compared to the TN's coverage.

[0187] In addition, it can be assumed that the satellite is located at a very high position (altitude) compared to the TN, and that the proportion of TN coverage within the satellite coverage is very small. In this case, it can be assumed that the distance (C) at which the signal transmitted from the satellite to the ground reaches does not differ significantly regardless of where the UE is located within the TN coverage. For example, from the perspective of satellite coverage, the propagation delay between the satellite and the UE may show a large difference depending on where the UE is located, but within the TN coverage, the location of the UE may be a value within an acceptable range in terms of propagation delay between the satellite and the UE. For example, referring to Fig. 19, depending on whether the UE is located at position 'P' or position 'Q', the propagation delay from the satellite may differ by a distance 'X', and this can be a value related to the TN coverage. The higher the altitude at which the satellite is located, and the smaller the TN coverage, the smaller the difference in propagation delay with the satellite located within the TN coverage can be (negligibly small).

[0188] In addition, if the error between the actual propagation delay and the estimated propagation delay falls within the CP (Cyclic Prefix), downlink synchronization can be maintained. For example, this is because, in OFDM-based systems, time errors within the CP interval are permissible for symbol matching and maintaining reception synchronization. Assuming that the gNB uses a high frequency, the length of the CP will also increase, so a certain amount of error can be overcome. Therefore, the propagation delay between the satellite and the UE (e.g., the value determined by C in Fig. 18) can be interpreted as the same value regardless of the UE's position within the TN coverage. For example, variations in propagation delay caused by changes in the UE's position (P, Q, etc.) within the TN coverage can be considered within the CP allowable error range, and 'C' can be treated as a constant for the entire TN coverage.

[0189] Specifically, the gNB can transmit the synchronization information of the NTN (e.g., SSB and / or PSS and / or SSS) to the UE via the TN path as if it were transmitted by the NTN path. For example, the gNB can transmit signals related to the synchronization information of the NTN, such as SSB, via the TN path based on the following method. Meanwhile, the propagation delay can be expressed as d / s, where d is the distance and s is the speed of light in wireless communication (e.g., the speed of propagation or a constant / approximate value equivalent thereto).

[0190] - The gNB can determine the distance between the gNB and the gateway (A in Fig. 18). The gNB can measure (or calculate) the propagation delay T(A) using the said distance (distance between the gNB and the gateway). For example, the gNB can calculate T(A) through A / s.

[0191] - The gNB may not be able to directly perceive the distance between the satellite and the UE (C in Fig. 18). For example, even if the UE can accurately measure its location using GNSS or other positioning techniques, reporting its location to the gNB may entail security risks (e.g., privacy infringement due to exposure of location information or the possibility of malicious tracking). In this regard, it can be assumed that the UE does not report its location to the gNB. Therefore, under this assumption, the gNB may not know the distance between the satellite and the UE. Contrary to this assumption, if the UE is allowed to report its location information to the gNB (e.g., location reporting is approved according to a predefined security policy, or mutual authentication and an encrypted secure channel are established), the gNB can calculate the distance between the satellite and the UE using the location information reported by the UE and measure the propagation delay () based on this.

[0192] - As described above, if the gNB cannot determine the location of the UE due to security issues, the gNB can estimate the propagation delay by considering the distance between the gNB and the satellite as the distance between the satellite and the UE. For example, the location of the gNB can be assumed to be a fixed location, and since the satellite's position can be derived using satellite orbit information (e.g., orbital elements or ephemeris information, etc.), the gNB can calculate the distance between the gNB and the satellite. In this case, the gNB can estimate the propagation delay for the UE by considering the calculated distance between the gNB and the satellite as the distance between the satellite and the UE. Alternatively, the gNB may estimate the propagation delay between the satellite and the UE by adding the gNB's elevation information to the distance between the gNB and the satellite. For example, the elevation information may include the gNB's installation altitude, altitude relative to sea level, or height relative to the reference ground, and the gNB can estimate the propagation delay between the satellite and the UE by using the value obtained by adding the elevation information to the distance value between the gNB and the satellite (or a correction value based thereon).

[0193] Based on the propagation delay estimated in this way, the gNB can transmit the Synchronization Signal Block (SSB) signal, which is to be transmitted to the UE via the NTN path, via the TN path. For example, when the SSB for the NTN path is transmitted via the NTN path, the gNB can transmit the SSB signal via the TN path by also taking into account the propagation delay to the UE (e.g., propagation delay between the UE and the satellite or propagation delay between the gNB and the satellite). For example, the gNB can control the SSB transmission timing via the TN path to correct the arrival time of the SSB to be received by the UE by reflecting the propagation delay occurring in the NTN path (including the propagation delay estimated based on the propagation delay between the satellite and the UE). For example, the gNB can delay the transmission timing of the SSB by the amount of propagation delay of the SSB transmitted to the UE through the NTN path, but advance the transmission timing of the SSB by the amount of TN propagation between the gNB and the UE, and transmit the SSB for the NTN path to the UE through the TN path. For example, the gNB can be configured such that the SSB transmitted through the TN path matches the arrival timing of the SSB transmitted through the NTN path from the UE's perspective by (i) setting a delay amount corresponding to the propagation delay in the NTN path, and (ii) advancing the transmission timing by the amount corresponding to the propagation delay in the TN path (e.g., propagation delay or processing delay in the terrestrial network section between the gNB and the UE).

[0194] - When a Synchronization Signal Block (SSB) signal that is supposed to be transmitted via the NTN path is transmitted via the TN path, the UE can synchronize the downlink and / or uplink of the NTN by monitoring the TN path. For example, by using the SSB (or timing information based thereon) received via the TN path to estimate or correct the reference timing required in the NTN path, the UE can perform NTN synchronization procedures (e.g., acquiring downlink synchronization, aligning uplink timing, correcting timing offset, etc.) without directly monitoring the NTN path itself (e.g., an NTN path that is deactivated). For example, the UE may form a TN / NTN multipath, where the NTN path is deactivated and the TN path is active. In this case, the UE may not need to separately monitor the NTN path to synchronize or maintain synchronization of the NTN path. For example, an inactive NTN path may mean that the UE does not perform data transmission or reception through the NTN path, or that the NTN path is not selected from the perspective of the receiver / base station connection procedure. Even in this case, the UE can maintain or update information required for NTN synchronization by using the monitoring results from the active TN path (e.g., reception results of the SSB associated with the NTN path or synchronization-related parameters). This operation can help save the UE's power.For example, by not performing additional receive operations (e.g., separate RF chain activation, search / synchronization signal detection, measurement execution, etc.) to monitor the NTN path, the receive operation time and / or power consumption associated with circuit operation for the NTN path can be reduced, and when the activation of the NTN path is indicated, the activation of the NTN path and the transmission and reception of data / signals through the NTN path can be performed without performing a separate synchronization acquisition procedure.

[0195] Alternatively, if synchronization information of the NTN is transmitted via the TN path, the UE may need to identify whether the synchronization information (e.g., SSB) received via the TN path corresponds to the NTN (or NTN path) or the TN (or TN path). For example, the UE may need to identify which transmission path (e.g., TN path or NTN path) the received SSB or synchronization-related message / signal corresponds to. For example, even if the TN / NTN paths are connected to the same gNB, the PCell IDs (Primary Cell Identifiers) may differ if the TN path and / or NTN path use different cells. In this case, the UE can distinguish / identify whether the synchronization information transmitted via the TN path is for the TN or the NTN based on the PCell ID or Cell ID. Conversely, if the TN-NTN path is connected to the same gNB and uses the same cell, the UE may perceive the SSB for the TN path (or SSB for TN) and the SSB for the NTN path (or SSB for NTN) as values ​​transmitted from the same gNB / same cell. In this case, the UE may obtain the same PCell ID (or PCI) value for both SSBs. Therefore, in such cases, it must be possible to inform the UE whether the synchronization signal (e.g., SSB) transmitted through the TN path is a synchronization signal for the NTN path. To indicate that the SSB transmitted through the TN path is a synchronization signal for the NTN path, the following methods may be considered.

[0196] - In order for the UE to recognize that an SSB transmitted through the TN path is a synchronization signal for the NTN path, it is necessary to include information (e.g., an identifier, a flag, an indication bit, or a specific sequence / configuration value, etc.) in the SSB (or the synchronization signal associated with the SSB) indicating that it is a synchronization for the NTN (or the NTN path). Specifically, the Physical Broadcast Channel (PBCH) of the SSB for synchronization of the NTN path transmitted through the TN path may include an indication to indicate that the SSB corresponds to the NTN path. For example, the indication may be set using a reserved bit or an unused field (or an expandable bit field) within the PBCH, and the UE can identify whether the SSB received through the TN path is a TN synchronization signal or an NTN synchronization signal by reading the indication during the PBCH decoding process.

[0197] - The PCell ID included in the SSB for the NTN path transmitted over the TN path can be set to a virtual value. For example, the gNB can transmit the NTN SSB over the TN path by setting the PCell ID included in the NTN SSB to 'Y' even if the actual PCell ID is 'X'. At this time, since the 'Y' value may differ from the actual cell identifier, the gNB can separately establish a mapping relationship to the UE using messages such as RRC (Radio Resource Control) (e.g., system information, dedicated RRC reconfiguration messages, or separate configuration information) stating that “an SSB containing PCell ID 'Y' received over the TN path should be considered as an NTN SSB corresponding to the actual PCell ID 'X'”. For example, based on the mapping information transmitted via RRC, etc., the UE can interpret / consider that the SSB received over the TN path is an SSB corresponding to PCell ID 'X' of the NTN path when the PCell ID of the SSB is 'Y'.

[0198] Meanwhile, whether the synchronization signal of the NTN can be transmitted within an acceptable error range via the TN path may not always be possible, as it depends on values ​​related to the satellite's height (e.g., satellite altitude or satellite-to-ground distance characteristics) and the TN's coverage (e.g., propagation delay and / or geographical coverage range of the TN section between the gNB and the UE), as previously explained. For instance, the “acceptable error range” may include cases where the difference in arrival time between an SSB received directly by the UE via the NTN or NTN path and an SSB received via the TN or TN path is within the Cyclic Prefix (CP) of the OFDM symbol. In other words, depending on whether the timing difference caused by the transmission of the SSB for the NTN path via the TN path exists within the range that the CP can absorb, synchronization maintenance / acquisition may or may not be valid from the UE's perspective. Accordingly, the gNB may inform the UE having TN / NTN multipath whether it can support the operation described above (e.g., the operation of transmitting a synchronization signal / SSB for NTN or an NTN path within a tolerance through a TN path) through a configuration, etc.

[0199] As described above, when NTN synchronization signals (e.g., SSB) are transmitted over the TN path, there is an advantage that the UE can synchronize or maintain the NTN path even if it monitors only the TN path. However, even if a UE with a TN-NTN path can synchronize the NTN path through the TN path (e.g., even if the NTN path is in a de-active state), it is necessary to monitor the link quality of the NTN path (e.g., signal strength or quality indicators such as RSRP, RSRQ, SINR, etc.). For instance, since the link quality of the NTN path can be utilized for determining whether to activate the NTN path, path selection or switching, resource configuration, and link maintenance / recovery procedures in the future, measuring the quality of the NTN path (continuously / periodically) may be required separately from maintaining synchronization. To this end, the UE needs to monitor PSS / SSS / DMRS, etc., transmitted over the NTN path. Therefore, such signal strength (or link quality) monitoring may need to be performed via the NTN path. For example, even if the UE receives the NTN synchronization signal via the TN path, it is necessary to directly receive and measure the signals transmitted via the NTN path (e.g., PSS / SSS / DMRS) to measure the link quality of the NTN path.

[0200] In consideration of these points, the gNB may set a period (or time period and / or frequency period) for which PSS / SSS / DMRS or SSB are periodically transmitted solely for (link quality) measurement over the NTN path. For example, the time period may refer to a time period during which measurement signals are transmitted for the UE to calculate the link quality (e.g., RSRP, RSRQ, SINR, etc.) of the NTN path, and the gNB may be configured to periodically transmit measurement PSS / SSS / DMRS or measurement SSB during that period. And / or, the frequency period may be configured to transmit within a specific carrier, Bandwidth Part (BWP), and / or frequency band. For example, the gNB can set frequency resources (e.g., a specific carrier or a specific BWP) and time resources (e.g., a specific slot / subframe / frame interval) for transmitting the measurement signal, and the UE can monitor at least one reference signal for quality measurement (e.g., a measurement PSS / SSS / DMRS or a measurement SSB) through the NTN path according to such settings. The frequency / time intervals and periodicity (e.g., repetition period, measurement window length, measurement opportunity interval, etc.) for quality measurement of such NTN path can be set through the TN path. And / or, the period of the PSS / SSS / DMRS or SSB for measurement of the NTN path may differ from the period of synchronous transmission of the actual NTN path. For example, the SSB transmission period for maintaining NTN synchronization and the measurement SSB (or measurement PSS / SSS / DMRS) transmission period for measuring link quality can be set independently of each other, and depending on the purpose of link quality measurement, a longer period (or a shorter period) can be set. In this case, depending on the degree of link quality (e.g., quality of the NTN pass), the period for which measurement is performed can also be set via the TN pass.For example, if the link quality reported by the UE (e.g., quality of the NTN path or link through NTN) or the link estimated by the gNB (e.g., quality of the NTN path or link through NTN) is good, the measurement period can be set relatively long (e.g., the transmission period of the signal for quality measurement is set longer than the transmission period of the signal for synchronization), and if the link quality (e.g., quality of the NTN path or link through NTN) is degraded, the measurement period can be set relatively short (e.g., the transmission period of the signal for quality measurement is set shorter than the transmission period of the signal for synchronization).

[0201] As such, the proposed method can maintain NTN (downlink) synchronization solely through monitoring the UE's TN path, even if the NTN path for a UE possessing / forming an NTN-TN multipath is in a de-active state. In this case, link quality measurement of the NTN path can be configured such that a separate PSS / SSS / DMRS for quality measurement is transmitted (via the NTN path) over a separate frequency interval and / or time interval. For example, the separate frequency / time interval may be a value set for the NTN path, and the UE can be configured to monitor only the signal / reference signal transmitted through the NTN path during the set limited frequency interval and / or limited time interval. Accordingly, since synchronization can be maintained without the UE continuously monitoring the NTN path to maintain synchronization, and thereby the link quality of the NTN path can be effectively measured, this can help reduce the transmission power of the NTN path (e.g., the transmission power of the measurement signal and / or the power required for constant synchronization signal transmission). For example, by restricting the transmission interval of measurement signals, unnecessary transmission and reception on the satellite / NTN transmitter side can be reduced, and consequently, transmission and reception power for the NTN path can be effectively reduced. Additionally, the signals for these quality measurements can be configured differently from the SSB signal cycle for the initial connection. For instance, the transmission / measurement cycle of the signal for measuring link quality on the NTN path can be configured to monitor / measure much less frequently (or much more frequently) than the SSB cycle for the initial connection. In this case, it may be helpful to dynamically measure the quality of the NTN path based on the UE's mobility (e.g., movement speed, movement pattern, or frequency of passing cell / beam boundaries).

[0202] FIG. 20 is a diagram illustrating a method for a base station to transmit a signal for obtaining synchronization for the NTN path and / or a reference signal for quality measurement to a UE that has formed a TN path and an NTN path.

[0203] As described above, the base station can transmit and receive data / control signals through a TN path (hereinafter referred to as the first link) directly connected to the UE and an NTN path (hereinafter referred to as the second link) through at least one satellite. For example, the base station may form not only the first link but also the second link with the UE and communicate with the UE through at least one of the two links. Meanwhile, the base station may activate either the first link or the second link and deactivate the other.

[0204] Specifically, referring to FIG. 20, a base station may form a first link with a UE in step S201. Here, the first link may be a wireless access path based, for example, on a terrestrial network (TN), and may be a communication path through which control signals and / or data signals are transmitted and received between the base station and the UE. For example, the first link may be established between the UE and the base station as the UE performs an access procedure while located within the cell coverage of the base station. Additionally, the first link may be an access path that is maintained by default between the UE and the base station, and may be used as a path for the formation of a second link described later, support for synchronization acquisition, and / or transmission of measurement-related setting information.

[0205] In step S203, the base station may form a second link connected to the UE via a satellite associated with a non-terrestrial network (NTN). Here, the second link may be an NTN-related communication path including, for example, a base station, a gateway, a satellite, and a UE. For example, the UE may form a TN-NNT multi-path environment or a heterogeneous link environment by additionally possessing the second link in addition to the first link. Furthermore, the first link and the second link may be managed by the same base station entity. For example, the base station may manage the terrestrial link and the non-terrestrial link together for the UE and operate the first link and the second link according to service requirements, link quality, resource status, and / or policies.

[0206] In step S205, the base station may transmit a Synchronization Signal Block (SSB) for acquiring synchronization of the second link. Here, the SSB may include a Primary Synchronization Signal (PSS), a Secondary Synchronization Signal (SSS), and a Physical Broadcast Channel (PBCH). The SSB for acquiring synchronization of the second link may be transmitted via the first link rather than the second link. For example, the base station may transmit an SSB, which is originally intended to be used for acquiring or maintaining synchronization related to the second link, to the UE via the first link rather than the second link. Accordingly, the UE can acquire or maintain a synchronization reference for the second link based on the SSB received via the first link, even without directly monitoring the second link at all times. For example, even if the UE keeps the second link in an inactive state, it can obtain a reference timing related to downlink synchronization and / or uplink synchronization for the second link using the SSB transmitted via the first link.

[0207] As described above, the SSB for the second link transmitted through the first link may be delayed based on the propagation delay associated with the second link. For example, a base station may adjust the transmission timing of the SSB transmitted through the first link by considering the expected arrival time when the SSB reaches the UE through the second link. Accordingly, from the perspective of the UE, the SSB received through the first link may be configured to have timing characteristics similar to the arrival time of the synchronization signal corresponding to the second link. And / or, the SSB may be delayed based on the value obtained by subtracting the propagation delay associated with the first link from the propagation delay associated with the second link. For example, a base station may calculate the difference between the expected propagation delay in the second link and the propagation delay in the first link, and may delay the transmission timing of the SSB for synchronization acquisition for the second link based on a value corresponding to said difference. In other words, by correcting the difference between the arrival timing when transmitted through the second link and the arrival timing when transmitted through the first link, the base station can more accurately use the SSB received by the UE through the first link as a signal for synchronization acquisition of the second link.

[0208] Here, the propagation delay associated with the second link may be a value estimated based on the distance between the base station and the satellite, or a value directly calculated based on the location of the UE and the location of the satellite. For example, the base station may calculate the distance between the base station and the satellite using its own location information and satellite-related information obtainable through the satellite's orbit information, ephemeris information, and / or SIB19, etc. The base station may estimate the propagation delay associated with the second link based on the calculated distance and propagation speed. For example, if the exact location of the UE is not reported to the base station, the base station may use the distance between the base station and the satellite as an approximation or substitute value for the distance between the satellite and the UE. For example, if the altitude of the satellite is sufficiently high and the range of TN coverage is relatively small, the deviation in distance between the satellite and the UE due to changes in the UE's location within TN coverage may exist within an acceptable error range; therefore, the base station may estimate the propagation delay of the second link relatively accurately based on the distance between the base station and the satellite.

[0209] And / or, the PBCH of the SSB may include instruction information to indicate that it is a synchronization signal associated with the second link. For example, the UE may need to identify whether the SSB received through the first link is a synchronization signal for the first link itself or a signal for acquiring synchronization of the second link. To this end, the base station may include a reserved bit, an extended bit field, a flag, or a predefined indicator within the PBCH to inform the UE that the SSB is a synchronization signal associated with the second link. The UE may read the instruction information during the process of decoding the PBCH and identify the received SSB as a signal to be used for acquiring or maintaining synchronization of the second link. Alternatively, the SSB may include a virtual cell ID (identifier) ​​to identify that it is a synchronization signal associated with the second link. For example, the base station may set a separate cell identification value distinct from the actual cell ID in association with the SSB, thereby causing the UE to interpret the SSB received through the first link as a synchronization signal for the second link. Here, the virtual cell ID does not actually represent a separate independent cell, but may be a logical identifier to identify that the SSB transmitted through the first link corresponds to the second link. Based on the virtual cell ID, the UE can recognize that the received SSB is a synchronization signal associated with the second link. For example, the virtual cell ID may be determined based on the sum of values ​​predefined in the cell ID (identifier) ​​of the base station. For example, if the actual cell ID of the base station is the first value, the virtual cell ID may be determined by adding a pre-set / defined offset value or a pre-set / defined correction value to the first value.Accordingly, the UE can identify that the SSB is a synchronization signal of the second link if the cell ID value associated with the received SSB has a certain relationship with the actual cell ID.

[0210] And / or, the method by the base station may further include the step of transmitting a measurement signal through the second link for measuring the quality of the second link. For example, an SSB transmitted through the first link may be used for acquiring or maintaining synchronization of the second link, but in order to measure the actual link quality of the second link, it may be necessary for the UE to directly receive the measurement signal transmitted through the second link. To this end, the base station may transmit at least one measurement signal, such as a PSS, SSS, DMRS, and / or a measurement SSB, through the second link. The measurement signal may be a signal intended for measuring the link quality of the second link, such as RSRP, RSRQ, SINR, received power, and / or received quality. Additionally, the measurement signal may be configured to be transmitted restrictively according to a separate time interval, a separate frequency interval, a specific slot, a specific BWP, or a specific period. Accordingly, even if the UE does not constantly monitor the second link, it can measure the quality of the second link by receiving a reference signal for measurement through the second link only during a set measurement interval, and as a result, reduce the power consumption of the UE.

[0211] FIG. 21 is a diagram illustrating a method for obtaining synchronization for the NTN path among the TN path and NTN path formed by the UE with the base station.

[0212] Referring to FIG. 21, in step S211, the UE can form a first link with a base station. Here, the first link may be, for example, a TN-based terrestrial wireless access path, and may be a communication path through which control signals and / or data signals are transmitted and received between the UE and the base station. For example, the UE can establish the first link with the base station by performing an access procedure within the cell coverage of the base station. Additionally, the first link may be an access path that is basically maintained between the UE and the base station, and may be used as a path for receiving signals to support the formation of the second link and the acquisition of synchronization, which will be described later.

[0213] In step S213, the UE may form a second link connected to the base station via the NTN. Here, the second link may be an NTN communication path associated with a satellite, a gateway, and a base station. For example, by additionally forming the second link in addition to the first link, the UE may configure a multi-link or multi-path structure that possesses both a terrestrial-based link and a non-terrestrial-based link. Accordingly, the UE can expect additional transmission opportunities, coverage expansion, and / or improved link reliability through the second link, in addition to communication through the first link.

[0214] In step S215, the UE can receive an SSB for acquiring synchronization for the second link. Here, the synchronization of the second link may be acquired based on an SSB received through the first link rather than the second link. For example, the UE may acquire a synchronization reference for the second link using an SSB transmitted through the first link, rather than a synchronization signal received directly through the second link. For example, the UE may acquire a reference timing related to downlink synchronization and / or uplink synchronization of the second link based on an SSB received through the first link. In this way, the UE can perform synchronization procedures related to the second link using synchronization information transmitted through the first link, without having to continuously monitor the second link itself directly to maintain / acquire synchronization for the second link. Accordingly, the burden of the UE performing a separate continuous monitoring operation for the second link may be reduced, and consequently, this may help reduce the power consumption of the UE.

[0215] Here, the SSB may include a PSS, an SSS, and a PBCH. For example, the UE can obtain a synchronization reference related to the second link using the PSS and the SSS, and obtain system information or additional identification information associated with the SSB through the PBCH. In other words, the UE can perform a synchronization acquisition procedure for the second link using the basic components of the SSB received through the first link. Therefore, the SSB transmitted through the first link, even though it is received through the first link in terms of the transmission path, can be interpreted as a signal block to support synchronization acquisition of the second link in terms of function.

[0216] And / or, additionally, the SSB received through the first link may be a signal transmitted with a delay by the base station. For example, the UE may interpret the SSB received through the first link not simply as a signal transmitted at the time of transmission of the first link, but as a signal whose transmission time has been adjusted by the base station to reflect the propagation delay associated with the second link. Specifically, the SSB may be transmitted through the first link at a delayed time corresponding to the expected time of arrival when transmitted through the second link. Alternatively, the SSB may be transmitted with a delay based on a value corresponding to the difference between the propagation delay associated with the second link and the propagation delay associated with the first link. Accordingly, the UE can obtain a timing reference that substantially corresponds to the synchronization signal received through the second link, even when using the SSB received through the first link. Thus, the UE can more accurately obtain or maintain downlink synchronization and / or uplink synchronization of the second link based on the SSB transmitted through the first link.

[0217] Alternatively, the UE may receive a reference signal for measuring the quality of the second link through the second link. For example, an SSB received through the first link may be used for acquiring or maintaining synchronization of the second link, but a reference signal for measuring the actual link quality of the second link may be received separately through the second link. The reference signal may include, for example, a PSS, an SSS, a DMRS, and / or a measurement SSB. In this case, the UE may determine the reception time, measurement time, and / or monitoring interval of the reference signal received through the second link based on the SSB received through the first link. For example, based on the synchronization criteria of the second link acquired through the first link, the UE may recognize time resources and / or frequency resources where the measurement reference signal exists on the second link, and measure the link quality by receiving the reference signal from the said resources. Accordingly, even if the UE does not constantly monitor the second link, it can receive the reference signal of the second link only in the necessary measurement interval using the synchronization information obtained through the first link, thereby allowing the UE to measure the quality of the second link while reducing its power consumption.

[0218] Alternatively, the SSB received through the first link may include information indicating that the SSB is for the second link. For example, the UE may need to identify whether the SSB received through the first link is a synchronization signal for the first link itself or a synchronization signal to support synchronization acquisition of the second link. To this end, the SSB may include instruction information to indicate that the SSB is a synchronization signal associated with the second link. For example, the instruction information may be provided in the form of a flag, reserved bit, extended bit field, or preset indicator included within the PBCH. By reading the instruction information during the process of decoding the PBCH, the UE can recognize that the SSB received through the first link is a signal to be used for synchronization acquisition or synchronization maintenance of the second link. Accordingly, the UE can process the SSB by distinguishing it from a synchronization signal for the first link itself and can appropriately use it as a synchronization standard for the second link. Alternatively, the SSB received through the first link may include separate cell identification information to identify that it pertains to the second link. For example, the SSB may include a virtual cell ID distinct from an actual cell ID, and the UE can identify that the SSB is a synchronization signal associated with the second link based on the virtual cell ID. Such an identification structure can help the UE clearly distinguish the use of the SSB, particularly in an environment where the first link and the second link are associated with the same base station or the same cell.

[0219] In this way, the proposed invention can improve the synchronization accuracy and synchronization maintenance reliability of the NTN link by allowing the base station to transmit the SSB via the TN with a delay to reflect the propagation delay associated with the NTN path, thereby enabling the UE to more accurately acquire a timing reference corresponding to the second link even when using the SSB received through the first link. And / or, the proposed invention can effectively reduce the power consumption of the UE by allowing the UE to acquire or maintain synchronization of the NTN link without constantly monitoring the deactivated NTN link, by transmitting the SSB for acquiring synchronization of the NTN path via the TN path instead of the NTN path.

[0220] Example of a communication system to which the invention is applied

[0221] 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.

[0222] 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.

[0223] FIG. 22 illustrates a communication system to which the present invention is applied.

[0224] Referring to FIG. 22, 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.

[0225] 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).

[0226] 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.

[0227] Example of a wireless device to which the present invention is applied

[0228] FIG. 23 illustrates a wireless device that can be applied to the present invention.

[0229] Referring to FIG. 23, 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. 22.

[0230] 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.

[0231] Specifically, the first wireless device or base station (100) may include a processor (102) and a memory (104) connected to a transceiver (106). The memory (104) may include at least one program capable of performing operations related to the embodiments described with reference to FIGS. 16 through 21 in the section “Method for reducing power of disabled link in NTN-TN multiple connection”. The operations include forming a first link with a UE (User Equipment); forming a second link connected to the UE via a satellite associated with an NTN (non-terrestrial network); and transmitting a Synchronization Signal Block (SSB) for acquiring synchronization of the second link, wherein the SSB includes a Primary Synchronization Signal (PSS), a Secondary Synchronization Signal (SSS), and a Physical Broadcast Channel (PBCH), and the SSB for acquiring synchronization of the second link may be transmitted through the first link rather than the second link.

[0232] Alternatively, a processing device may be configured including a processor (102) and a memory (104) that control a base station (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 causing the base station to form a first link with a UE (User Equipment); to form a second link connected to the UE via a satellite associated with a non-terrestrial network (NTN); and to transmit a Synchronization Signal Block (SSB) for acquiring synchronization of the second link, wherein the SSB includes a Primary Synchronization Signal (PSS), a Secondary Synchronization Signal (SSS), and a Physical Broadcast Channel (PBCH), and the SSB for acquiring synchronization of the second link may be transmitted through the first link rather than the second link.

[0233] 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.

[0234] Specifically, the second wireless device or UE (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 described with reference to FIGS. 16 through 21 in the section “Method for reducing power of disabled link in NTN-TN multiple connection”. The operations include controlling the RF transceiver to form a first link with a base station and forming a second link connected to the base station via a non-terrestrial network (NTN), wherein the synchronization of the second link is obtained based on a Synchronization Signal Block (SSB) received via the first link rather than the second link, and the SSB may include a Primary Synchronization Signal (PSS), a Secondary Synchronization Signal (SSS), and a Physical Broadcast Channel (PBCH).

[0235] 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.

[0236] 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.

[0237] 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, codes, 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.

[0238] 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.

[0239] Examples of wireless device applications to which the present invention is applied

[0240] FIG. 24 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. 22).

[0241] Referring to FIG. 24, the wireless device (100, 200) corresponds to the wireless device (100, 200) of FIG. 23 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. 24. For example, the transceiver(s) (114) may include one or more transceivers (106, 206) and / or one or more antennas (108, 208) of FIG. 23. 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).

[0242] 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. 22, 100a), a vehicle (Fig. 22, 100b-1, 100b-2), an XR device (Fig. 22, 100c), a portable device (Fig. 22, 100d), a home appliance (Fig. 22, 100e), an IoT device (Fig. 22, 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. 22, 400), a base station (Fig. 22, 200), a network node, etc. Wireless devices can be used in a movable or fixed location depending on the use—e.g., service.

[0243] In FIG. 24, 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 partially 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 connected via a wire, and the control unit (120) and the first unit (e.g., 130, 140) may be connected wirelessly 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.

[0244] Examples of vehicles or autonomous vehicles to which the present invention is applied

[0245] FIG. 25 illustrates a vehicle or autonomous vehicle to which the present invention applies. The vehicle or autonomous vehicle may be implemented as a mobile robot, vehicle, train, manned / unmanned aerial vehicle (AV), ship, etc.

[0246] Referring to FIG. 25, 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. 24.

[0247] 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.

[0248] 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.

[0249] 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.

[0250] 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.

[0251] 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).

[0252] 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.

[0253] 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.

[0254] 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.

[0255] The embodiments of the present invention as described above can be applied to various mobile communication systems.

Claims

1. In the method using a base station, Step of forming a first link with UE (User Equipment); A step of forming a second link connected to the UE via a satellite associated with an NTN (non-terrestrial network); and The method includes the step of transmitting an SSB (Synchronization Signal Block) for acquiring synchronization of the second link, and The above SSB includes PSS (Primary Synchronization Signal), SSS (Secondary Synchronization Signal), and PBCH (Physical Broadcast Channel), and A method in which the SSB for obtaining synchronization of the second link is transmitted through the first link rather than the second link.

2. In Paragraph 1, A method in which the above SSB is delayed and transmitted based on the propagation delay associated with the above second link.

3. In Paragraph 1, A method in which the above SSB is delayed and transmitted based on the value obtained by subtracting the propagation delay associated with the first link from the propagation delay associated with the second link.

4. In Paragraph 2, A method in which the propagation delay associated with the second link is a value estimated based on the distance between the base station and the satellite.

5. In Paragraph 1, A method comprising instruction information for indicating that the PBCH of the above SSB is a synchronization signal associated with the second link.

6. In Paragraph 1, A method comprising a virtual cell ID (identifier) ​​for identifying that the above SSB is a synchronization signal associated with the second link.

7. In Paragraph 6, A method in which the above virtual cell ID is determined based on the sum of predefined values ​​of the cell ID (identifier) ​​of the base station.

8. In Paragraph 1, A method further comprising the step of transmitting a measurement signal for measuring the quality of the second link through the second link.

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, Form a first link with the UE (User Equipment); Forming a second link connected to the UE via a satellite associated with the NTN (non-terrestrial network); and It includes transmitting an SSB (Synchronization Signal Block) for acquiring synchronization of the second link, and The above SSB includes PSS (Primary Synchronization Signal), SSS (Secondary Synchronization Signal), and PBCH (Physical Broadcast Channel), and The SSB for acquiring synchronization of the second link is at least one non-transient computer-readable recording medium transmitted through the first link rather than the second link.

10. Regarding base stations, RF (Radio Frequency) transceiver; and It includes a processor connected to the above RF transceiver, and The above processor controls the RF transceiver to form a first link with the UE (User Equipment), forms a second link connected to the UE via a satellite associated with the NTN (non-terrestrial network), and transmits a Synchronization Signal Block (SSB) for acquiring synchronization of the second link. The above SSB includes PSS (Primary Synchronization Signal), SSS (Secondary Synchronization Signal), and PBCH (Physical Broadcast Channel), and The SSB for acquiring synchronization of the second link is a base station transmitted through the first link, not the second link.

11. In Paragraph 10, The above SSB is a base station that is delayed and transmitted based on the propagation delay associated with the above second link.

12. In a processing device for controlling a base station, 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 cause the base station, Form a first link with the UE (User Equipment); Forming a second link connected to the UE via a satellite associated with the NTN (non-terrestrial network); and It includes transmitting an SSB (Synchronization Signal Block) for acquiring synchronization of the second link above, and The above SSB includes PSS (Primary Synchronization Signal), SSS (Secondary Synchronization Signal), and PBCH (Physical Broadcast Channel), and A processing device for obtaining synchronization of the second link, wherein the SSB is transmitted through the first link rather than the second link.

13. In a method using UE (User Equipment), Step of forming a first link with a base station; and It includes the step of forming a second link connected to the base station through an NTN (non-terrestrial network), The synchronization of the second link is obtained based on the SSB (Synchronization Signal Block) received through the first link rather than the second link, and A method in which the above SSB includes PSS (Primary Synchronization Signal), SSS (Secondary Synchronization Signal), and PBCH (Physical Broadcast Channel).

14. In Paragraph 13, A method in which, based on the second link being deactivated, the UE obtains synchronization for the second link based on the SSB received through the first link.

15. Regarding UE (User Equipment), RF (Radio Frequency) transceiver; and It includes a processor connected to the above RF transceiver, and The above processor controls the RF transceiver to form a first link with a base station and forms a second link connected to the base station through an NTN (non-terrestrial network). The synchronization of the second link is obtained based on the SSB (Synchronization Signal Block) received through the first link rather than the second link, and The above SSB is a UE comprising a PSS (Primary Synchronization Signal), a SSS (Secondary Synchronization Signal), and a PBCH (Physical Broadcast Channel).

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