Method and device for transmitting information by using PCI in non-terrestrial network system

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting a data transmission rate higher than that of a 4G communication system such as LTE. This method performed by user equipment in a wireless communication system using a non-terrestrial network (NTN), according to the present disclosure, may comprise the steps of: receiving a first physical cell ID (PCI) for a first cell from a first NTN base station; receiving a second PCI for the first cell from a second NTN base station; calculating a PCI gap (PCIG) corresponding to a difference between the first PCI and the second PCI; and identifying, within PCIG information, first cell information corresponding to the calculated PCIG. Other various embodiments identified through the specification are possible.

Description

Method and device for transmitting information using PCI in a non-terrestrial network system

[0001] The present disclosure relates to a wireless communication system, and more specifically, to a method and apparatus for transmitting information using a physical cell ID (PCI) in a non-terrestrial network (NTN) system.

[0002] Looking back at the evolution of wireless communication through successive generations, technologies have been developed primarily for human-oriented services, such as voice, multimedia, and data. Following the commercialization of 5G (5th Generation) communication systems, connected devices, which have been increasing explosively, are expected to be connected to communication networks. Examples of networked objects include vehicles, robots, drones, home appliances, displays, smart sensors installed in various infrastructures, construction machinery, and factory equipment. Mobile devices are expected to evolve into various form factors, such as augmented reality glasses, virtual reality headsets, and holographic devices. In the 6G (6th Generation) era, efforts are underway to develop improved 6G communication systems to connect hundreds of billions of devices and objects to provide diverse services. For this reason, 6G communication systems are being referred to as "beyond 5G" systems.

[0003] In the 6G communication system predicted to be realized around 2030, the maximum transmission speed is tera (i.e., 1,000 gigabit) bps (bit per second), and the wireless latency is 100 microseconds (μsec). In other words, compared to the 5G communication system, the transmission speed in the 6G communication system is 50 times faster, and the wireless latency is reduced to one-tenth.

[0004] To achieve such high data transmission speeds and ultra-low latency, 6G communication systems are being considered for implementation in the terahertz (THz) band (e.g., the 95 gigahertz (GHz) to 3 terahertz (3THz) band). Due to more severe path loss and atmospheric absorption phenomena compared to the millimeter wave (mmWave) band introduced in 5G, the importance of technologies capable of guaranteeing signal reach, or coverage, is expected to increase in the terahertz band. As key technologies to ensure coverage, new waveforms, beamforming, and multi-antenna transmission technologies such as massive Multiple-Input and Multiple-Output (MIMO), Full Dimensional MIMO (FD-MIMO), array antennas, and large-scale antennas, which are superior in terms of coverage compared to RF (Radio Frequency) devices, antennas, and OFDM (Orthogonal Frequency Division Multiplexing), must be developed. In addition, new technologies such as metamaterial-based lenses and antennas, high-dimensional spatial multiplexing technology using Orbital Angular Momentum (OAM), and Reconfigurable Intelligent Surface (RIS) are being discussed to improve the coverage of terahertz band signals.

[0005] In addition, to improve frequency efficiency and system network, development is underway in 6G communication systems for full duplex technology, in which uplink and downlink simultaneously utilize the same frequency resources at the same time; network technology that integrates satellites and HAPS (High-Altitude Platform Stations); network structure innovation technology that supports mobile base stations and enables network operation optimization and automation; dynamic spectrum sharing technology through collision avoidance based on spectrum usage prediction; AI-based communication technology that utilizes AI (Artificial Intelligence) from the design stage and internalizes end-to-end AI support functions to realize system optimization; and next-generation distributed computing technology that realizes services of complexity exceeding the limits of terminal computing capabilities by utilizing ultra-high performance communication and computing resources (Mobile Edge Computing (MEC), cloud, etc.). In addition, attempts are continuing to further strengthen connectivity between devices, further optimize networks, promote the softwareization of network entities, and increase the openness of wireless communication through the design of new protocols to be used in 6G communication systems, the implementation of hardware-based security environments, the development of mechanisms for the safe utilization of data, and the development of technologies regarding privacy maintenance methods.

[0006] Due to the research and development of such 6G communication systems, it is expected that a new dimension of hyper-connected experience will become possible through the hyper-connectivity of 6G communication systems, which encompasses not only connections between objects but also connections between people and objects. Specifically, it is projected that 6G communication systems will enable the provision of services such as truly immersive eXtended Reality (XR), high-fidelity mobile holograms, and digital replicas. Furthermore, services such as remote surgery, industrial automation, and emergency response, which are provided through 6G communication systems with enhanced security and reliability, will be applied in various fields including industry, healthcare, automotive, and home appliances.

[0007] Various embodiments disclosed in this document propose a method and apparatus for obtaining information using PCI in a non-terrestrial network (NTN) system.

[0008] A method performed by a terminal (user equipment) in a wireless communication system using a non-terrestrial network (NTN) according to various embodiments disclosed in this document may include the steps of receiving a first physical cell ID (PCI) for a first cell from a first NTN base station, receiving a second PCI for a first cell from a second NTN base station, calculating a PCI gap (PCI Gap) corresponding to the difference between the first PCI and the second PCI, and identifying first cell information corresponding to the calculated PCI G within the PCI G information.

[0009] In a wireless communication system using a non-terrestrial network (NTN) according to various embodiments disclosed in this document, a terminal (user equipment) includes a transceiver and a processor coupled to the transceiver, and the processor may be configured to receive a first physical cell ID (PCI) for a first cell from a first NTN base station and receive a second PCI for a first cell from a second NTN base station, calculate a PCI gap (PCI Gap) corresponding to the difference between the first PCI and the second PCI, and identify first cell information corresponding to the calculated PCI G within the PCI G information.

[0010] A method performed by a base station in a wireless communication system using a non-terrestrial network (NTN) according to various embodiments disclosed in this document comprises the steps of transmitting an update message for PCIG information to a terminal (user equipment), receiving an update completion message from the terminal in response to the update message, and transmitting a physical cell ID (PCI) for a first cell to the terminal, wherein the PCI is used to calculate a PCIG (PCI gap), and the PCIG can be used to identify first cell information corresponding to the PCIG within the PCIG information.

[0011] In a wireless communication system according to various embodiments disclosed in this document, a base station comprises a transceiver and a processor coupled to the transceiver, and the processor is configured to transmit an update message for PCIG information to a terminal (user equipment), receive an update completion message from the terminal in response to the update message, and transmit a physical cell ID (PCI) for a first cell to the terminal, wherein the PCI is used to calculate a PCIG (PCI gap), and the PCIG can be used to identify first cell information corresponding to the PCIG within the PCIG information.

[0012] FIG. 1 illustrates a change in the physical cell ID (PCI) of a satellite cell in a non-terrestrial network system according to one embodiment of the present disclosure.

[0013] FIG. 2 illustrates an example in which a terminal identifies NTN cell information using a PCIG (PCI gap) in a non-terrestrial network system according to an embodiment of the present disclosure.

[0014] FIG. 3 illustrates the operation of a terminal in a non-terrestrial network system according to one embodiment of the present disclosure, in which the terminal identifies NTN cell information using a PCIG.

[0015] FIG. 4 illustrates an example in which a terminal identifies NTN cell information using a PCIG in a non-terrestrial network system according to an embodiment of the present disclosure.

[0016] FIG. 5 illustrates an example in which a terminal identifies NTN cell information using a PCIG group (PCIG group) in a non-terrestrial network system according to an embodiment of the present disclosure.

[0017] FIG. 6 illustrates the operation of a terminal searching for a terrestrial network using PCI in a non-terrestrial network system according to one embodiment of the present disclosure.

[0018] FIG. 7 illustrates the operation of a terminal searching for a terrestrial network using PCI in a non-terrestrial network system according to one embodiment of the present disclosure.

[0019] FIG. 8 illustrates an example in which a terminal according to an embodiment of the present disclosure identifies NTN cell information using a PCIG and a PCIG group.

[0020] FIG. 9 illustrates an example of transmitting PCIG information or PCIG group information between a terminal and a network entity according to an embodiment of the present disclosure.

[0021] FIG. 10 is a flowchart illustrating the operation of a terminal according to one embodiment of the present disclosure.

[0022] FIG. 11 is a flowchart illustrating the operation of a terminal according to one embodiment of the present disclosure.

[0023] FIG. 12 is a flowchart illustrating the operation of a base station according to one embodiment of the present disclosure.

[0024] FIG. 13 illustrates the structure of a terminal according to one embodiment of the present disclosure.

[0025] FIG. 14 illustrates the structure of a base station according to one embodiment of the present disclosure.

[0026] FIG. 15 illustrates the structure of a network entity according to one embodiment of the present disclosure.

[0027] In relation to the description of the drawings, the same or similar reference numerals may be used for identical or similar components.

[0028] Various aspects of the claimed subject matter are described with reference to the drawings, in which similar reference numerals are used to denote similar elements. In the following description, for the purpose of explanation, a number of specific details are described to provide a sufficient understanding of one or more embodiments. However, it may be apparent that the embodiments can be practiced without these specific details.

[0029] The terms used in this disclosure are used merely to describe specific embodiments and are not intended to limit the scope of other embodiments. A singular expression may include a plural expression unless the context clearly indicates otherwise. Terms used herein, including technical or scientific terms, may have the same meaning as generally understood by those skilled in the art described in this disclosure. Terms used in this disclosure that are defined in a general dictionary may be interpreted as having the same or similar meaning as they have in the context of the relevant technology, and are not to be interpreted in an ideal or overly formal sense unless explicitly defined in this disclosure. In some cases, even terms defined in this disclosure are not to be interpreted to exclude the embodiments of this disclosure.

[0030] Terms used in the following description to refer to signals (e.g., message, signal, signaling, occasion), terms for operations (e.g., step, method, process, procedure), terms for data (e.g., information, parameter, variable, value, bit, symbol, codeword), terms for channels, terms for control information (e.g., DCI (downlink control information), MAC CE (medium access control codeword element), RRC (radio resource control) signaling), terms for network entities, terms for device components, etc., are examples provided for the convenience of explanation. Accordingly, the present disclosure is not limited to the terms described below, and other terms having equivalent technical meanings may be used.

[0031] Various embodiments of the present disclosure are described herein in relation to wireless terminals and / or base stations. A wireless terminal may refer to a device that provides voice and / or data access to a user. A wireless terminal may be connected to a computing device, such as a laptop computer or a desktop computer, or may be a self-contained device, such as a personal digital assistant (PDA). A wireless terminal may also be referred to as a system, subscriber unit, subscriber station, mobile station, mobile, mobile device, remote station, remote terminal, access terminal, user terminal, terminal, wireless communication device, user agent, user device, or user equipment. A wireless terminal may be a subscriber station, wireless device, cellular phone, PCS phone, wireless phone, Session Initiation Protocol (SIP) phone, wireless local loop (WLL) station, personal digital assistant (PDA), portable device with wireless access capability, or other processing device connected to a wireless modem. A base station (e.g., an access point) may refer to a device within an access network that communicates with wireless terminals at a wireless interface through one or more sectors. The base station can include an Internet Protocol (IP) network by converting received wireless interface frames into IP packets and can act as a router between the wireless terminal and the rest of the access network. The base station can also coordinate the management of attributes for the wireless interface.

[0032] Recently, active research has been conducted on non-terrestrial network (NTN) communication technology. NTN communication technology utilizes satellites as repeaters to establish communication coverage in areas where the installation of mobile communication base stations is physically or economically impossible (e.g., oceans, polar regions, remote areas, and the air). NTN communication technology refers to a technology that can be utilized not only in NTN using the LTE (Long Term Evolution) standard used in existing terrestrial networks and NR (New Radio) standards that include functions for NTN performance enhancement, but also in 6G communication systems expected to be commercialized by 2030.

[0033] In NTN, since satellites act as base stations or base station antennas, terminals must perform NTN communication by considering various phenomena caused by satellite mobility that do not occur in terrestrial networks. In non-terrestrial systems, terminals connected to NTN cells must communicate with satellites located at very long distances compared to terrestrial systems. Consequently, high transmission power may be essential to deliver radio waves to distant base stations. Furthermore, due to signal attenuation caused by long distances, terminals experience frequent disconnections and retransmissions; this can lead to higher power consumption for terminals connected to NTN cells compared to those connected to terrestrial cells.

[0034] Accordingly, the terminal may need a process to acquire information related to NTN (e.g., satellite orbit information, latency between the satellite and the gateway, terrestrial network coverage, etc.). Currently, 3GPP (3 rd The generation partnership project describes an operation in which, in relation to NTN communication, a terminal can receive information through a broadcasting message from a base station connected to the satellite in order to acquire mobility information of the satellite.

[0035] Broadcasting messages include various information related to the satellite and the satellite cell formed by the satellite, including the satellite's position, velocity, and orbit information. For example, 3GPP defines the SIB (system information block) 19 message as a broadcasting message containing satellite mobility information in NR NTN. The information elements (IEs) included in SIB 19 in the Release 17 NR NTN standard defined by 3GPP are specifically listed in [Table 1] below.

[0036]

[0037]

[0038] A terminal capable of using the NR NTN standard can receive satellite mobility and direction information through broadcasting messages, and can determine whether to measure the frequency for time and frequency synchronization through the information.

[0039] However, in a non-terrestrial network system, a terminal connected to a satellite cell may have a relatively lower probability of successfully receiving a broadcasting message like [Table 1] due to lower communication performance compared to a terrestrial network, compared to the probability of receiving a broadcasting message in a terrestrial network system. In order for the terminal to increase the probability of receiving a broadcasting message in a non-terrestrial network, the size of the message must be small. However, since the terminal can perform actions to improve the performance of NTN communication as it receives various information, incompatible conditions may coexist, such as the need to receive a broadcasting message containing various information to improve the performance of NTN communication.

[0040] As described above, the method of transmitting NTN-related information to a terminal defined by NR NTN in Release 17 of 3GPP has a limitation in that while the message size must be small for the message to be successfully transmitted from a non-terrestrial network system to the terminal, the terminal must receive as much NTN-related information as possible to improve the performance of NTN communication. Additionally, there is a limitation in that the transmission of broadcasting messages such as SIB19 is possible only on terminals capable of using NR NTN (e.g., smartphones with NR Release 17 implemented) and on NTNs that have adopted NR NTN as a communication technology.

[0041] Accordingly, in order to overcome the limitations of terminals capable of limited NTN communication, a method is currently being discussed to allow terminals to receive NTN-related information while utilizing existing LTE (long term evolution) standard technology instead of NR. In other words, a method is being discussed to allow terminals to receive NTN-related information using a method other than the broadcasting messages defined in the NR NTN standard.

[0042] Terrestrial networks (TN) and non-terrestrial networks (NTN) using 3GPP-based mobile communication standards define a Physical Cell ID (PCI) to distinguish cell areas where a terminal can communicate. In terrestrial networks, network entities set different PCIs for each cell to distinguish them. The PCI set by the network entity can remain the same until the terminal changes the connected cell to another cell. PCIs can be set in various ways. For example, two different PCIs can be set sequentially, assigned dynamically depending on the status of the satellite cell, or a PCI can be set fixedly for each satellite.

[0043] Hereinafter, the NTN cell described in this disclosure may be a quasi-earth fixed cell. A quasi-earth fixed cell refers to a satellite cell formed in a specific area of ​​the Earth's surface. Since the satellites described in this disclosure (e.g., LE0 satellites and MEO satellites) move relative to the Earth's surface, they cannot continuously form a cell in a specific area. This disclosure illustrates a case where a quasi-earth fixed cell is formed in a specific area even if the satellite moves relative to the ground by rotating the antenna of the beam forming the satellite cell. For example, the NTN cell of FIG. 1 may represent a quasi-earth fixed cell in which the satellite maintains a constant position by rotating the beam antenna. Therefore, the PCI in the NTN cell described in this disclosure may allow the satellite forming the NTN cell to change continuously over time. That is, the PCI in the NTN cell may not be in a fixed form but may change dynamically by the network entity. If the satellite forming the NTN cell currently connected to the terminal changes, the PCI may change to the PCI set by the network entity for the satellite to be changed.

[0044] The satellites described in this disclosure are primarily LEO (low earth orbit) satellites. Compared to other satellites (GEO (geostationary earth orbit) and ME0 (medium earth orbit)), LE0 satellites located at lower altitudes have the advantage of low delay due to short radio wave round-trip times. However, because they move at a very high speed compared to other satellites, they have the characteristic of continuously changing frequency and time synchronization in non-mobile terminals or satellite antennas. Accordingly, a technology for calculating and correcting changes in frequency and time caused by satellite mobility is a major subject of discussion in NTN technology.

[0045] In other words, because LEO satellites forming cells in non-terrestrial networks move at high speeds, the time available to form a cell is limited when an LEO satellite forms a cell on the ground. Consequently, a terminal connected to a satellite cell (or NTN cell) formed on the ground may not be able to maintain a constant PCI. When the satellite forming the cell changes, the terminal receives a PCI different from the existing PCI, and the terminal can detect the change in the satellite by recognizing the change in PCI.

[0046] According to one embodiment of the present disclosure, in a non-terrestrial network system, a satellite network operator (SNO) or a mobile network operator (MNO) may set the PCI of a satellite cell. Additionally, the SNO or MNO may set the PCI so that a specific PCIG is maintained, allowing a terminal in the non-terrestrial network system to utilize the difference between PCIs (or PCIG). For example, the SNO or MNO may set the PCI so that the value of the PCIG becomes 1, as shown in [Table 2]. In one example, if the satellite forming the satellite cell changes, the PCI may increase or decrease by the characteristics of the satellite cell and the set value. That is, the SNO or MNO may set the PCIs of the target satellite cell based on the PCI of surrounding satellite cells or the configurable PCI. Meanwhile, the SNO refers to an operator that operates a satellite-based communication network, and the MNO refers to an operator that operates a terrestrial mobile communication network and operates a non-terrestrial network system in cooperation with the SNO.

[0047]

[0048] According to one embodiment of the present disclosure, PCI can be set according to a PCI setting formula as in [Equation 1]. At this time, PCI max represents the maximum number of PCIGs. For example, in [Table 2], PCI maxis 20. In one example, when the terminal calculates PCIG, the absolute value of the difference between the PCI received at time t and the PCI received at time t+1 according to [Equation 1] is PCI max The remainder after division can be identified as PCIG.

[0049] [Mathematical Formula 1]

[0050]

[0051] [Table 2] shows examples of various scenarios in which the value of PCIG can be set to 1. Referring to [Table 2], PCI can be set with a repeating constant value or with a PCI that increases or decreases sequentially. For example, in [Table 2], Scenario 1 can be set so that the PCI value is repeatedly set to 1 and 2, thereby maintaining the PCIG value of 1. Additionally, Scenario 2 can be set so that the values ​​3, 4, 5, ... are sequentially set so that the PCIG value of 1 is maintained. Scenario 3 can be set so that the PCI value is repeatedly set to 2, 3, 4, and 3, and Scenario 4 can be set so that the PCIG value of 1 is maintained or a randomly set value is maintained. Furthermore, Scenario 5 is an example where the PCI value is set so that the PCIG value of 1 is maintained or a randomly set value is maintained, similar to Scenario 4. Specifically, when the value of the first PCI is 1 and the value of the second PCI is 22, the terminal PCI at the value |1-22|=21 according to the PCI setting formula of [Equation 1] max = The remainder of dividing by 20, which is 1, can be calculated as PCI.

[0052] In one example, an SNO or MNO can set the PCI so that the value of PCIG is maintained at 3 as shown in [Table 3]. [Table 3] shows examples of various scenarios in which the value of PCIG can be set to 3. Referring to [Table 3], Scenario 1 can be set so that the value of PCIG is maintained at 3 by repeatedly setting the PCI value to 1 and 4. Additionally, Scenario 2 can be set so that the value of PCIG is maintained at 3 by sequentially setting the values ​​to 7, 10, 13, ... Scenario 3 can be set so that the value of PCIG is maintained at 6, 9, 12, and 9, and Scenario 4 can be set so that the value of PCIG is maintained at 3 by setting a random value. Additionally, Scenario 5 is an example in which the value of PCIG is maintained at 3 by setting a random value, similar to Scenario 4. Specifically, when the value of the first PCI is 6 and the value of the second PCI is 29, the terminal PCI at the value |6-29|=23 according to the PCI setting formula of [Equation 1] max = The remainder of dividing by 20, which is 3, can be calculated as PCI.

[0053]

[0054] As described above, in a non-terrestrial network system, the PCI of a satellite cell can be configured so that the terminal can identify PCIG information or PCIG group information by utilizing the PCIG. The terminal can obtain information about the satellite cell based on the calculated PCIG, and accordingly, can perform various operations to ensure smooth communication in the non-terrestrial network system.

[0055] Meanwhile, a terminal connected to an NTN cell described in the present disclosure may refer to a terminal connected to an NTN cell in an RRC CONNECTED state or in a camping state in an RRC IDLE state.

[0056] The base station in a non-terrestrial network (or, NTN base station) described in this disclosure may represent a satellite that performs the role of a base station relative to a satellite cell formed by a satellite through a beam to the Earth.

[0057] The NTN payload illustrated in this drawing may refer to an entity that generates a non-terrestrial network. The NTN payload may include satellites, HAPS (high-altitude pseudo satellites), etc., but in this disclosure, a satellite is illustrated as the NTN payload.

[0058] Hereinafter, the present disclosure proposes a method and apparatus for a terminal connected to an NTN cell in a non-terrestrial network system to receive a plurality of PCIs, identify the difference between PCIs (PCIG) or PCIG groups, and obtain metadata. At this time, NTN cell information (or cell metadata) may be included in the metadata. NTN cell information is information such as payload type, polarization type, satellite orbit type, satellite change type, satellite altitude, and MNO, which can be identified in the PCIG information.

[0059] FIG. 1 illustrates a change in the physical cell ID (PCI) of a satellite cell in a non-terrestrial network system according to one embodiment of the present disclosure. Specifically, FIG. 1 illustrates an example in which the PCI received by a terminal changes when the satellite forming the NTN cell in the non-terrestrial network system changes.

[0060] In FIG. 1, when the first satellite (NTN payload 1) (110) forms the NTN cell to which the terminal is connected, the terminal may receive a first PCI value for the NTN cell in relation to the first satellite (110) from a network entity. For example, the first PCI value received by the terminal in FIG. 1 may be 1. At this time, the network entity may represent the first satellite (110), a base station connected to the first satellite (110) and relaying the first satellite (110) and the terminal.

[0061] Subsequently, if the first satellite (110) moves and can no longer form an NTN cell, the satellite forming the NTN cell may be changed from the first satellite (110) to the second satellite (NTN payload 2) (120). At this time, the terminal may receive a second PCI value for the NTN cell in relation to the second satellite (120) from a network entity. At this time, the value of the second PCI may have a different value from the value of the first PCI. For example, the second PCI value received by the terminal in FIG. 1 may be 2. At this time, the network entity may represent the second satellite (120), a base station connected to the second satellite (120) and relaying the second satellite (120) to the terminal, etc.

[0062] Additionally, if the second satellite (120) moves and can no longer form an NTN cell, the satellite forming the NTN cell may be changed from the second satellite (120) to the third satellite (NTN payload 3) (120). The terminal may receive a third PCI value for the NTN cell in relation to the third satellite (130) from a network entity. At this time, the third PCI value may have a different value from the first PCI or the second PCI value. For example, the value of the third PCI received by the terminal in FIG. 1 may be 3. At this time, the network entity may represent the third satellite (120), a base station connected to the third satellite (120) and relaying between the third satellite (120) and the terminal, etc.

[0063] As described above, when the satellite forming the same NTN cell changes, the terminal connected to that NTN cell can receive different PCI values ​​whenever the satellite forming the NTN cell changes. The terminal can recognize that the satellite forming the NTN cell has changed when the received PCI value changes.

[0064] FIG. 2 illustrates an example in which a terminal identifies NTN cell information using a PCIG (PCI gap) in a non-terrestrial network system according to an embodiment of the present disclosure.

[0065] A terminal connected to an NTN cell can receive PCIs for the satellites forming the NTN cell. As the satellites forming the same NTN cell change, the terminal can receive different PCIs for each satellite. In one example, at time t1, the terminal can receive a first PCI value from a first satellite (NTN payload 1) (210) forming the NTN cell with a spot beam. The value of the first PCI may be, for example, i. Subsequently, after time x has elapsed from t1, the terminal can receive a second PCI value from a second satellite (NTN payload 2) (220) forming the NTN cell at time t1+x. The value of the second PCI may be, for example, j.

[0066] At this time, the terminal may receive the first PCI or the second PCI from a network entity other than the first satellite or the second satellite. In one example, the network entity may be a base station, MNO, SNO, etc., connected to the satellite and relaying the satellite and the terminal. For example, the terminal may receive the first PCI for the NTN cell of the first satellite from a first base station that performs non-terrestrial network communication with the first satellite. Additionally, the terminal may receive the second PCI for the NTN cell of the second satellite from a second base station that performs non-terrestrial network communication with the second satellite.

[0067] According to one embodiment of the present disclosure, a terminal can calculate the difference between PCIs received from a first satellite and a second satellite. The difference between the PCI values ​​can be represented as a PCIG (PCI gap). A PCIG can represent the absolute value of the difference between a PCI value received first and a PCI value received later. For example, the terminal of FIG. 2 can calculate a PCIG of |ij|, which is the absolute value of the difference between a first PCI value i and a second PCI value j.

[0068] Subsequently, the terminal can identify metadata corresponding to the PCIG calculated within the stored PCIG information. For example, if the PCIG calculated by the terminal in FIG. 2 is 1, the terminal can identify metadata A within the PCIG information that maps to the PCIG with a PCIG value of 1. In one example, the metadata may include NTN cell information (or cell metadata). NTN cell information may be information such as payload type, polarization type, satellite orbit type, satellite change type, satellite altitude, and MNO, which can be identified in the PCIG information.

[0069] For example, the metadata may include cell metadata as illustrated in the PCIG information of FIG. 4. In this case, the cell metadata may display information regarding whether a terrestrial network cell (TN neighboring cell) exists around the NTN cell to which the terminal is connected, information regarding the overlapping area between the NTN cell and the terrestrial network cell, information regarding polarization indicating whether the NTN cell is a right-hand circular polarization (RHCP) cell or a left-hand circular polarization (LHCP) cell, and information indicating the status of satellites capable of forming the NTN cell indicating whether there is continuous connectivity or discontinuous connectivity.

[0070] According to one embodiment of the present disclosure, a terminal can search for an operation corresponding to metadata A and perform the searched operation. For example, if metadata A identified by the terminal when the value of PCIG in FIG. 2 is 1 is the cell metadata “Same configuration with before cell” when the value of PCIG in FIG. 4 is 1, the terminal can search for “No change,” which is an operation corresponding to the cell metadata. Accordingly, if there was an operation previously performed, the terminal can maintain the previous operation without performing a new operation. As another example, if metadata B identified by the terminal when the value of PCIG in FIG. 2 is 2 is the cell metadata “TN non-neighboring cell” when the value of PCIG in FIG. 4 is 2, the terminal can search for “Disable HPLMN (TN) search procedure,” which is an operation corresponding to the cell metadata. Accordingly, the terminal may not perform an operation to search for a cell of the terrestrial network.

[0071] As described above, the terminal can determine whether additional operations are necessary (e.g., whether a terrestrial network search operation is necessary) by checking metadata corresponding to the calculated PCIG and searching for operations corresponding to the metadata. Accordingly, the terminal can perform various operations that can improve the communication performance of the terminal in an environment where NTN communication is performed. The PCIG information includes metadata mapped to the PCIG for each, and may represent NTN cell information corresponding to each metadata. Specifically, the PCIG information may include NTN cell information such as payload type, polarization type, satellite orbit type, satellite change type, satellite altitude, and MNO. For example, the PCIG information may include the information in [Table 4] described below.

[0072] Subsequently, the terminal may perform additional operations (or functions) based on the identified NTN cell information. In one example, if the identified cell information includes information that there exists a terrestrial network cell that overlaps with the NTN cell, the terminal may decide to perform a search for the terrestrial network cell. Additionally, if the identified cell information includes information regarding the overlapping area between the NTN cell and the terrestrial network cell, the terminal may perform an operation to adjust the interval (or period) for searching for the terrestrial network cell.

[0073] Meanwhile, PCIG information may be information stored in advance in the terminal, or information received by the terminal from a network entity (e.g., satellite, RAN (radio access network), core network (CN), OAM (operations, administration, and maintenance), telecom server, UE vendor server, TN server, etc.). When the terminal receives PCIG information from a network entity, the terminal may obtain PCIG information by receiving an update message of PCIG information from the network entity. In one example, the terminal may update existing information by receiving PCIG information that is not stored in advance from the network entity, or by receiving updated PCIG information from the network entity when there is PCIG information stored in advance but it is not the latest information.

[0074] FIG. 3 illustrates the operation of a terminal in a non-terrestrial network system according to one embodiment of the present disclosure, in which the terminal identifies cell information and satellite information using PCIG.

[0075] Referring to FIG. 3, in operation 310, the terminal can receive the first physical cell ID (PCI) from the NTN cell. For example, the first PCI may be the first PCI for the first satellite that forms the spot beam of the NTN cell received by the terminal in FIG. 2.

[0076] In operation 320, the terminal may receive a second PCI from the same NTN cell as in operation 310. The second PCI may be different from the first PCI. For example, the second PCI may be the second PCI for the second satellite received by the terminal in FIG. 2.

[0077] In operation 330, the terminal can calculate PCIG (PCI gap), which is the difference between the first PCI and the second PCI received. For example, the terminal can calculate PCIG as |ij|, which is the difference between the first PCI with a PCI value of i received in FIG. 2 and the second PCI with a PCI value of j.

[0078] In operation 340, the terminal can identify metadata mapped to a PCIG calculated based on PCIG information stored in the terminal. In one example, the terminal can identify metadata corresponding to a PCIG calculated from PCIG information that is stored in advance or received from a network entity. Subsequently, the terminal can identify metadata represented in the metadata. For example, if the PCIG calculated by the terminal in FIG. 2 is 1, the terminal can identify metadata A mapped to a PCIG where the value of the PCIG is 1 within the PCIG information. Additionally, the terminal can identify cell information corresponding to metadata A.

[0079] In one example, the metadata may include NTN cell information (or cell metadata). NTN cell information may be information such as payload type, polarization type, satellite orbit type, satellite change type, satellite altitude, and MNO, which can be identified in the PCIG information. For example, the metadata may include cell metadata as illustrated in the PCIG information of FIG. 4. In this case, the cell metadata may indicate whether a terrestrial network cell (TN neighboring cell) exists around the NTN cell to which the terminal is connected, information about the overlapping area between the NTN cell and the terrestrial network cell, information about polarization indicating whether the NTN cell is a right-hand circular polarization (RHCP) cell or a left-hand circular polarization (LHCP) cell, and information indicating the status of satellites capable of forming the NTN cell indicating whether there is continuous connectivity or discontinuous connectivity.

[0080] In operation 350, the terminal can search for and perform additional operations (or functions) related to the NTN cell based on the identified cell metadata. In one example, if the identified cell information includes information that there is a terrestrial network cell that overlaps with the NTN cell, the terminal may decide to perform a search for the terrestrial network cell. Additionally, if the identified cell information includes the proportion of overlap with the terrestrial network cell, the terminal may perform an operation to adjust the search interval for the terrestrial network cell.

[0081] For example, in FIG. 4, when the PCIG value is 1, the cell metadata is “Same configuration with before cell,” the terminal can search for “No change,” which is an action corresponding to the cell metadata. Accordingly, if there was an action previously performed, the terminal can maintain the previous action without performing a new action. As another example, in FIG. 4, when the PCIG value is 2, the cell metadata is “TN non-neighboring cell,” the terminal can search for “Disable HPLMN (TN) search procedure,” which is an action corresponding to the cell metadata. Accordingly, the terminal can not perform an action to search for a cell of the terrestrial network.

[0082] FIG. 4 illustrates an example in which a terminal identifies NTN cell information using a PCIG in a non-terrestrial network system according to an embodiment of the present disclosure.

[0083] Referring to FIG. 4, the NTN cell formed at the terminal location is formed by a spot beam of the first satellite (NTN payload 1), and the value of the PCI of the said NTN cell is 5 (for example, 1 in FIG. 4). st (recorded PCI= 5) may be possible. In one example, a terminal within an NTN cell can recognize that the PCI of the NTN cell formed by the spot beam of the first satellite is 5 by utilizing a broadcasting message.

[0084] If the first satellite moves and the first satellite's spot beam can no longer form NTN cells, the satellite forming the NTN cells may be changed from the first satellite to the second satellite (NTN payload 2). In this case, the value of the PCI formed by the second satellite's spot beam is 7 (for example, 2 in FIG. 4). nd (recorded PCI= 7) may be possible. In one example, the terminal can recognize that the PCI value of the NTN cell formed by the spot beam of the second satellite has changed from 5 to 7.

[0085] The terminal can calculate the difference between the previous PCI, PCI=5, and the latest PCI, PCI=7, in relation to the NTN cell to which the terminal is connected. For example, in FIG. 4, the difference between the two PCIs (or PCIG) calculated by the terminal may be |5-7|=2.

[0086] Subsequently, the terminal can identify metadata mapped to the PCIG calculated from the PCIG information stored in the terminal. In one example, the metadata may include NTN cell information (or cell metadata). NTN cell information can be identified in the PCIG information as information such as payload type, polarization type, satellite orbit type, satellite change type, satellite altitude, and MNO. In one example, the terminal can identify cell metadata mapped to PCIG=2 and information on the PCIG corresponding procedure from the stored PCIG information. For example, if the value of the PCIG calculated by the terminal of FIG. 4 in relation to the NTN cell is 2, the terminal can identify the information of “TN non-neighboring cell” in the cell metadata and recognize that there are no terrestrial network cells neighboring the NTN cell. Additionally, the terminal can identify the information of “Disable HPLMN (home public land mobile network) search procedure” in the PCIG corresponding procedure and recognize that a procedure to search for terrestrial network cells is impossible. Accordingly, the terminal can disable the operation of searching for terrestrial network cells existing in the vicinity of the NTN cell to which the terminal is connected. Through this, the terminal can efficiently prevent the time and power consumption required to search for terrestrial network cells that do not exist in the vicinity of the cell to which it is connected.

[0087] Meanwhile, PCIG information may include cell information or satellite information such as payload type, polarization type, satellite orbit type, satellite change type, satellite altitude, and MNO. For example, the PCIG information stored in the terminal in FIG. 4 may include metadata indicating the status of satellites capable of forming an NTN cell, indicating whether the NTN cell is a right-hand circular polarization (RHCP) cell or a left-hand circular polarization (LHCP) cell when the PCI value is 3 or 4, information regarding polarization indicating whether the NTN cell is a continuous connectivity or discontinuous connectivity when the PCI value is 5 or 6, and information indicating whether the NTN cell is a continuous connectivity or discontinuous connectivity when the PCI value is 7 or 8.

[0088] PCIG information may be information stored in advance in the terminal, or information received by the terminal from a network entity (e.g., satellite, RAN (radio access network), core network (CN), OAM (operations, administration, and maintenance), telecom server, UE vendor server, TN server, etc.). When the terminal receives PCIG information from a network entity, the terminal may obtain PCIG information by receiving an update message of PCIG information from the network entity. In one example, the terminal may update existing information by receiving PCIG information that is not stored in advance from the network entity, or by receiving updated PCIG information from the network entity when there is PCIG information stored in advance but it is not the latest information.

[0089] FIG. 5 illustrates an example in which a terminal identifies NTN cell information using a PCIG group (PCIG group) in a non-terrestrial network system according to an embodiment of the present disclosure.

[0090] According to one embodiment of the present disclosure, a terminal can calculate a PCIG using two PCIs for an NTN cell to which the terminal is connected, recognize the calculated PCIG in units of PCIG groups, and identify NTN cell information by recognizing the PCIG group containing the PCIG. A PCIG group may be a parameter representing a certain range of a PCIG. For example, in Example 1 of FIG. 5, a PCIG group may include a first PCIG group in which the value of the PCIG is 1 to 200, a second PCIG group in which the value of the PCIG is 201 to 400, and a third PCIG group in which the value of the PCIG is 401 to 504.

[0091] In one example, the terminal can identify NTN cell information to which a calculated PCIG is mapped within PCIG information using two PCIs as shown in FIG. 4, as well as recognize a PCIG group (or PCIGG (PCIG group)) corresponding to the calculated PCIG. The terminal can additionally identify metadata mapped to the recognized PCIG group within the PCIG group information. Accordingly, the terminal can perform additional operations based on the NTN cell information mapped to the PCIG group. In one example, the metadata may include NTN cell information (or cell metadata). NTN cell information may be information such as payload type, polarization type, satellite orbit type, satellite change type, satellite altitude, and MNO, which can be identified in the PCIG information. For example, the metadata may include cell metadata illustrated in the PCIG group information of FIG. 5. At this time, the cell metadata may include information such as the type of satellite forming the NTN cell to which the terminal is connected (e.g., the payload type of Example 1 in FIG. 5), the operator forming the terrestrial network existing around the NTN cell (e.g., the MNO (mobile network operator) of Example 2 in FIG. 5).

[0092] Referring to FIG. 5, the NTN cell formed at the terminal location is formed by a spot beam of the first satellite (NTN payload 1), and the value of the PCI of the said NTN cell is 5 (for example, 1 in FIG. 5). st (recorded PCI= 5) may be possible. In one example, a terminal within an NTN cell can recognize that the PCI of the NTN cell formed by the spot beam of the first satellite is 5 by utilizing a broadcasting message.

[0093] If the first satellite moves and the first satellite's spot beam can no longer form NTN cells, the satellite forming the NTN cells may be changed from the first satellite to the second satellite (NTN payload 2). In this case, the value of the PCI formed by the second satellite's spot beam is 30 (for example, 2 in FIG. 5 nd (recorded PCI=30). In one example, the terminal can recognize that the PCI value of an NTN cell formed by the spot beam of the second satellite has changed from 5 to 30. The terminal can calculate the difference between the previous PCI, PCI=5, and the latest PCI, PCI=30, in relation to the NTN cell to which the terminal is connected. For example, in FIG. 5, the difference between the two PCIs (or PCIG) calculated by the terminal may be |5-30|=25.

[0094] In Example 1 of FIG. 5, when the calculated PCIG is 25, the terminal can recognize that it is included in a first PCIG group in which the value of the PCIG is 1 to 200, in PCIG group information that is stored in advance or received from a network entity. Subsequently, the terminal can identify metadata that maps to the first PCIG group within the PCIG group information.

[0095] The terminal can identify information regarding cell metadata and PCIG corresponding procedures mapped to the first PCIG group corresponding to PCIG 1 to 200 in the stored PCIG group information. Additionally, it can optionally check additional instructions. For example, if the PCIG group identified by the terminal is the first PCIG group, the terminal can identify the satellite type as “transparent payload cell” in the cell metadata. Additionally, the terminal can identify information regarding “reuse base station’s information after handover” in the PCIG corresponding procedure to recognize that the base station’s information (e.g., parameters used when connecting the base station and the terminal) can be reused even after the terminal has handed over from an NTN cell to another cell. Additionally, the terminal can recognize information as additional instructions that the serving DU (distributed unit) and serving CU (centralized unit) will not change after the handover.

[0096] The PCIG groups illustrated in Example 2 of FIG. 5 may include a first PCIG group with a PCIG value of 1 to 100, a second PCIG group with a PCIG value of 101 to 200, and a third PCIG group with a PCIG value of 201 to 300.

[0097] If the calculated PCIG is 25, the terminal may recognize that it is included in a first PCIG group in which the value of the PCIG is 1 to 100, based on PCIG group information that is stored in advance or received from a network entity. Subsequently, the terminal may identify metadata mapped to the first PCIG group within the PCIG group information. The terminal may identify information regarding cell metadata and PCIG corresponding procedures mapped to the first PCIG group corresponding to PCIG values ​​1 to 100 in the stored PCIG group information. Additionally, it may optionally check additional instructions. For example, if the PCIG group identified by the terminal is the first PCIG group, the terminal may identify “MNO 1” in the cell metadata as information regarding the MNO (mobile network operator) operating a cell adjacent to the NTN cell. In addition, the terminal can identify the information “search only MNO 1 in PLMN / HPLMN search procedure” in the PCIG corresponding procedure and search for MNO 1 when performing the procedure to search for a cell in the terrestrial network. In addition, the terminal can recognize, as an additional instruction, information that a cell in the terrestrial network close to the NTN cell is operated by MNO 1.

[0098] Meanwhile, the information included in the PCIG group information may include not only the information shown in Example 1 or Example 2 of Figure 5, but also the information included in the PCIG information. For example, the PCIG group information may include cell information or satellite information such as payload type, polarization type, satellite orbit type, satellite change type, satellite altitude, and MNO.

[0099] As described above, the terminal can not only identify metadata using PCIG, but also identify another metadata by identifying a PCIG group corresponding to the additionally identified PCIG. That is, the terminal can not only obtain information related to the NTN cell to which the terminal is connected using PCIG, but can also obtain additional information using a PCIG group. Through this, the terminal can simultaneously obtain various information related to the NTN cell. However, separate processing time may be required for the process of identifying not only PCIG but also PCIG groups. FIG. 6 illustrates the operation of a terminal searching for a terrestrial network using PCI in a non-terrestrial network system according to an embodiment of the present disclosure.

[0100] Non-terrestrial networks (NTN) and terrestrial networks (TN) can be interconnected in the same way as roaming between carriers. In one example, the non-terrestrial network forming an NTN cell can be seen as a VPLMN (visited public land mobile network), the terminal connected to the NTN cell can be seen as a terminal roaming with the VPLMN, and the terrestrial network that the terminal is searching for can be seen as a HPLMN (home public land mobile network).

[0101] According to LTE or NR standards, a terminal roaming in a VPLMN can search for HPLMNs, which are terrestrial network cells, at regular intervals. That is, a terminal connected to an NTN cell searches for HPLMN frequencies at regular intervals; if the presence of an HPLMN forming a terrestrial network cell is detected, the terminal can change the PLMN connected from the VPLMN to the HPLMN. In this case, the interval at which the terminal searches for the HPLMN is the EF stored in the terminal's USIM (Universal Subscriber Identity Module). HPPLMNIt can be determined based on the (elementary file higher priority PLMN search period) value. In one example, a terminal complying with LTE or NR standards uses the EF stored in the USIM HPPLM HPLMN search can be performed at time intervals corresponding to the product of 6 minutes.

[0102] In non-terrestrial network systems, since NTN cells formed by satellites can be located anywhere on Earth, if an NTN cell is formed in a location where a terrestrial network is difficult to exist, such as the ocean, remote areas, or the air, the terminal cannot perform the operation of changing the connection from the NTN cell to the terrestrial network, HPLMN. Therefore, for a terminal located within an NTN cell where there is no overlapping area between the NTN cell and the terrestrial network, the operation of searching for the HPLMN may be unnecessary.

[0103] In addition, even when the coverage of NTN cells and terrestrial network cells overlaps, if the terminal searches for all operators (or carriers) rather than just the operators of the terrestrial network cells that overlap with the NTN cells, time and power consumption may occur due to unnecessary operator searches.

[0104] Accordingly, to reduce the processing time and power consumption required for HPLMN search by the terminal, the terminal may not perform HPLMN search in locations where no HPLMN communication area exists. Additionally, even when the coverage of an NTN cell overlaps with that of a terrestrial network cell, the terminal may search only for the operator (or carrier) of the terrestrial network cell that overlaps with the NTN cell, thereby reducing time and power consumption caused by unnecessary HPLMN search. To disable the HPLMN search function in locations where no HPLMN communication area exists, the terminal may require information regarding the overlapping area between the NTN cell to which the terminal is connected and the terrestrial network cell associated with HPLMN.

[0105] FIG. 6 presents a method for effectively reducing power consumption and measurement time for a terminal to use PCIG to identify information about a terrestrial network cell near an NTN cell, and to determine whether to search for an HPLMN or to determine the search cycle of an HPLMN based on the identified information. The terminal of FIG. 6 can be applied not only to terminals that follow the NR NTN standard but also to terminals that perform LTE-based NTN communication.

[0106] According to one embodiment of the present disclosure, a terminal can calculate a PCIG for an NTN cell to which the terminal is connected and identify cell information of a terrestrial network adjacent to the NTN cell that maps to the calculated PCIG within the PCIG information. The terminal can determine whether to search for an HPLMN based on the identified cell information of the terrestrial network.

[0107] Referring to FIG. 6 (A), the NTN cell formed at the terminal location is formed by a spot beam of the first satellite (NTN payload 1), and the value of the PCI of the said NTN cell is 1 (e.g., 1 st (recorded PCI= 1) may be possible. In one example, a terminal within an NTN cell can recognize that the PCI of the NTN cell formed by the spot beam of the first satellite is 1 by utilizing a broadcasting message.

[0108] If the first satellite moves and the first satellite's spot beam can no longer form NTN cells, the satellite forming the NTN cells may change from the first satellite to the second satellite (NTN payload 2). In this case, the value of the PCI formed by the second satellite's spot beam is 3 (e.g., 2 nd (recorded PCI= 3) may be possible. In one example, the terminal can recognize that the PCI value of the NTN cell formed by the spot beam of the second satellite has changed from 1 to 3.

[0109] The terminal can calculate the difference between the previous PCI, PCI=1, and the latest PCI, PCI=3, in relation to the NTN cell to which the terminal is connected. For example, in (A) of FIG. 6, the difference between the two PCIs (or PCIG) calculated by the terminal may be |1-3|=2.

[0110] Subsequently, the terminal can identify metadata mapped to the PCIG calculated from the PCIG information stored in the terminal. In one example, the metadata may include NTN cell information (or cell metadata). NTN cell information may be information such as payload type, polarization type, satellite orbit type, satellite change type, satellite altitude, and MNO, which can be identified in the PCIG information. In one example, the terminal can identify metadata mapped to PCIG=2 in the stored PCIG information. For example, in the case of (A) of FIG. 6, the terminal can recognize information that there are no terrestrial network cells adjacent to the NTN cell. Accordingly, the terminal may not perform the procedure of searching for HPLMN cells to search for terrestrial network cells. The terminal may disable HPLMN search while connected to the NTN cell.

[0111] Referring to FIG. 6 (B), the NTN cell formed at the terminal location is formed by a spot beam of the first satellite (NTN payload 1), and the value of the PCI of the said NTN cell is 1 (e.g., 1 st (recorded PCI= 1) may be possible. In one example, a terminal within an NTN cell can recognize that the PCI of the NTN cell formed by the spot beam of the first satellite is 1 by utilizing a broadcasting message.

[0112] If the first satellite moves and the first satellite's spot beam can no longer form NTN cells, the satellite forming the NTN cells may change from the first satellite to the second satellite (NTN payload 2). In this case, the value of the PCI formed by the second satellite's spot beam is 4 (e.g., 2nd (recorded PCI= 4) may be possible. In one example, the terminal can recognize that the PCI value of the NTN cell formed by the spot beam of the second satellite has changed from 1 to 4.

[0113] The terminal can calculate the difference between the previous PCI, PCI=1, and the latest PCI, PCI=4, in relation to the NTN cell to which the terminal is connected. For example, in (B) of FIG. 6, the difference between the two PCIs (or PCIG) calculated by the terminal may be |1-4|=3.

[0114] Subsequently, the terminal can identify metadata mapped to the PCIG calculated from the PCIG information stored in the terminal. In one example, the terminal can identify metadata mapped to PCIG=3 from the stored PCIG information. For example, in the case of (B) in FIG. 6, the terminal can recognize information that there is a terrestrial network cell adjacent to the NTN cell based on the PCIG information mapped to the value of PCIG=3, and that the operator operating the terrestrial network cell is MNO 2. Accordingly, the terminal can decide to perform a procedure to search for an HPLMN that searches for a terrestrial network cell, and can set the target MNO for the search for the HPLMN to MNO 2. In this case, the terminal can measure the frequency of MNO 2 to check whether a PLMN change to MNO 2 is possible in case a connection to the terrestrial network is required.

[0115] As described above, the terminal can determine whether to search for a terrestrial network cell close to the NTN cell to which the terminal is connected based on PCIG information mapped to the calculated PCIG, and accordingly, can efficiently prevent the time and power consumption required to search for a terrestrial network that does not exist around the NTN cell to which the terminal is connected.

[0116] FIG. 7 illustrates an operation in which a terminal searches for a terrestrial network using PCI in a non-terrestrial network system according to one embodiment of the present disclosure. FIG. 7 illustrates an example in which a PCIG is calculated as in FIG. 6 to determine whether to search for an HPLMN, which is a terrestrial network, and specifically, an HPLMN search period (or interval) is determined.

[0117] According to one embodiment of the present disclosure, a terminal can calculate a PCIG for an NTN cell to which the terminal is connected and identify information regarding an overlapping area of ​​an NTN cell mapped to the calculated PCIG within the PCIG information and an adjacent terrestrial network to the NTN cell. Based on the identified overlapping area information of the terrestrial network, the terminal can determine whether to search for an HPLMN and the search period of the HPLMN.

[0118] FIG. 7 (A) illustrates an example in which information is recognized that there are no terrestrial network cells adjacent to the NTN cell, similar to FIG. 6 (A) described above. Accordingly, the terminal of FIG. 7 (A) may not perform the procedure of searching for HPLMN cells to search for terrestrial network cells. The terminal may disable HPLMN search while connected to the NTN cell.

[0119] Referring to FIG. 7 (B), the NTN cell formed at the terminal location is formed by a spot beam of the first satellite (NTN payload 1), and the value of the PCI of the said NTN cell is 1 (e.g., 1 st (recorded PCI= 1) may be possible. In one example, a terminal within an NTN cell can recognize that the PCI of the NTN cell formed by the spot beam of the first satellite is 1 by utilizing a broadcasting message.

[0120] If the first satellite moves and the first satellite's spot beam can no longer form NTN cells, the satellite forming the NTN cells may change from the first satellite to the second satellite (NTN payload 2). In this case, the value of the PCI formed by the second satellite's spot beam is 4 (e.g., 2nd (recorded PCI= 4) may be possible. In one example, the terminal can recognize that the PCI value of the NTN cell formed by the spot beam of the second satellite has changed from 1 to 4.

[0121] The terminal can calculate the difference between the previous PCI, PCI=1, and the latest PCI, PCI=4, in relation to the NTN cell to which the terminal is connected. For example, in FIG. 6, the difference between the two PCIs (or PCIG) calculated by the terminal may be |1-4|=3.

[0122] The terminal can identify metadata mapped to the PCIG calculated within the PCIG information stored in the terminal. In one example, the metadata may include NTN cell information (or cell metadata). NTN cell information can be identified in the PCIG information as information such as payload type, polarization type, satellite orbit type, satellite change type, satellite altitude, and MNO. The terminal can identify metadata mapped to PCIG=3 in the stored PCIG information. For example, in the case of (B) of FIG. 7, the terminal can recognize information that there is a terrestrial network cell adjacent to the NTN cell, and that there is a terrestrial network cell that overlaps with the NTN cell in a small area. Accordingly, the terminal can decide to perform a procedure to search for HPLMN and can increase the HPLMN search cycle. If the overlap area between the NTN cell and the terrestrial network cell is small, the area where the connection can be changed from the non-terrestrial network to the terrestrial network is small, so power waste can be prevented by increasing the HPLMN search cycle.

[0123] FIG. 8 illustrates an example in which a terminal according to an embodiment of the present disclosure identifies NTN cell information using a PCIG and a PCIG group.

[0124] As the satellite moves, the satellite forming a certain NTN cell may change. Accordingly, the terminal can continuously receive PCI whenever the satellite forming the NTN cell changes. Accordingly, the terminal can calculate and obtain multiple PCIGs whenever the satellite forming the NTN cell changes.

[0125] FIG. 8 illustrates an example in which, as the satellites move from right to left, the satellite forming the NTN cell to which the terminal is connected changes from NTN payload 1 to NTN payload 2, and subsequently changes sequentially to NTN payload 3, 4, 5, and 6. As the satellite forming the NTN cell changes, the PCI received by the terminal may change as shown in the diagram of FIG. 8. For example, the PCI associated with payload 1 received by the terminal may change to 1, the PCI associated with payload 2 to 4, the PCI associated with payload 3 to 8, and so on. Accordingly, the PCIG values ​​calculated by the terminal may also change.

[0126] When the satellite forming the NTN cell changes, the terminal calculates the changed PCIG values ​​and additionally identifies PCIG groups (or PCIGGs) corresponding to the PCIG values. The terminal can identify cell information mapped to the PCIG values ​​within the PCIG information and cell information mapped to the PCIGG within the PCIG group information.

[0127] In FIG. 8, the terminal can calculate the PCIG values ​​as 3, 8, 10, 21, and 451 as the satellite forming the NTN cell changes from payload 1 to 6. Accordingly, the terminal can recognize that the current NTN cell performs RHCP polarization through cell information mapped to the PCIG values ​​3, 8, 10, 1, and 460 calculated within the stored PCIG information, that the type of satellite payload is a regenerative payload capable of on-board processing, and that the altitude of the satellite is 550 km.

[0128] In FIG. 8, the terminal can identify a PCIG group containing a calculated PCIG value. As the satellite forming the NTN cell changes from payload 1 to 5, the PCIG group can be identified as a first PCIG group with PCIG values ​​of 1 to 450, and as the satellite changes from payload 5 to 6, the PCIG group can be identified as a second PCIG group with PCIG values ​​of 451 to 504. Accordingly, through cell information mapped to the identified PCIG group within the stored PCIG group information, the terminal can recognize payloads 1 to 5 as 'inclined,' meaning they are satellites rotating in a satellite orbit with an inclination of approximately 40 to 50 degrees. Additionally, payloads 5 to 6 can be recognized as 'polar,' meaning they are satellites rotating in a satellite orbit with an inclination of nearly 90 degrees.

[0129] As described above, a terminal connected to an NTN cell can recognize information about the NTN cell by identifying the PCIG that changes as the satellites forming the NTN cell change. Accordingly, based on the acquired information about the satellites and cells, the terminal can explore various technologies to connect with the NTN cell in non-terrestrial networks or to improve the performance of the terminal itself.

[0130] According to one embodiment of the present disclosure, the information that may be included in PCIG information or PCIG group information may be as shown in [Table 4] below. However, the information that may be included in PCIG information or PCIG group information is not limited to the information in [Table 4] and may include information related to non-terrestrial network systems.

[0131]

[0132] In [Table 4], payload type indicates the type of payload carried by the satellite. In one example, transparent payload refers to a method where the satellite receives a signal from the ground, amplifies it, and then transmits it back to Earth, while regenerative payload refers to a method where the satellite demodulates and remodulates the signal received from the ground before transmitting it back to the ground. Polarization refers to the polarization method of the signal used by the satellite, indicating Right Circular Polarization (RHCP), Left Circular Polarization (LHCP), and Linear Polarization. Satellite orbit type indicates the satellite orbit type, and satellite change type indicates information regarding the type of change in inter-satellite connectivity. MNO indicates information about the ground network operator existing around the NTN cell. Finally, satellite altitude indicates the altitude from the NTN cell to the satellite.

[0133] In one example, the information that a terminal can obtain through PCIG information or PCIG group information may include information included in the SIB (system information block) 19 message defined in the NR standard that is efficient to transmit through PCIG (e.g., payload type, polarization, satellite orbit type, satellite change type, etc.). In addition, not only the information included in SIB 19 but also information not defined in the NR standard (e.g., MNO information, satellite altitude, etc.) may be transmitted.

[0134] The terminal can perform various operations to improve the terminal's performance, such as acquiring Doppler effects, changes in time synchronization, satellite mobility prediction based on latitude and orbit information, and terrestrial network cell coverage information, by utilizing information about non-terrestrial network systems included in PCIG information or PCIG group information.

[0135] FIG. 9 illustrates an example of transmitting PCIG information or PCIG group information between a terminal and a network entity according to an embodiment of the present disclosure.

[0136] Satellite and cell information may be included in PCIG information or PCIG group information and stored in the terminal. PCIG information or PCIG group information may be stored in advance when the terminal is manufactured. Alternatively, the terminal may obtain PCIG information or PCIG group information by receiving an update message for PCIG information or PCIG group information from a network entity. The terminal may update existing information by receiving PCIG information or PCIG group information that is not stored in advance from a network entity, or by receiving updated PCIG information or PCIG group information from a network entity if there is pre-stored PCIG information or PCIG group information but it is not the latest information.

[0137] FIG. 9 illustrates the operation of a terminal receiving and updating PCIG information or PCIG group information from a network entity. At this time, the network entity may include a satellite, a RAN (radio access network), a core network (CN), an OAM (operations, administration, and maintenance), a telecom server, a UE vendor server, a TN server, etc.

[0138] FIG. 9 (A) illustrates an example in which a terminal receives a request from a network entity to update PCIG information or PCIG group information. Referring to FIG. 9 (A), in operation 910, the network entity may send a PCIG update message or a PCIG group update message to the terminal. The PCIG update message or the PCIG group update message may include a PCIG (or PCIG group) description, a PCIG (or PCIG group) value, information corresponding to the PCIG (or PCIG group) value, etc. In one example, the PCIG update message or the PCIG group update message may include information requesting that the PCIG information or PCIG group information be updated.

[0139] In operation 920, the terminal can update PCIG information or PCIG group information based on information included in the update message received in operation 910. In one example, if the terminal has previously stored PCIG information or PCIG group information, it can change the existing PCIG information or PCIG group information to the PCIG information or PCIG group information received in operation 910.

[0140] In operation 930, the terminal may send a PCIG or PCIG group update complete message to a network entity. The PCIG or PCIG group update complete message may include information about the PCIG information or PCIG group information that the terminal updated in operation 920.

[0141] FIG. 9 (B) illustrates an example of a terminal requesting PCIG information or PCIG group information from a network entity. Referring to FIG. 9 (B), in operation 940, the terminal may transmit a message requesting PCIG information or PCIG group information to a network entity.

[0142] In one example, if a problem occurs between the PCIG value calculated based on the PCI received from the NTN cell to which the terminal is connected and the actual operation performed, it can be recognized that the PCIG information or PCIG group information stored in the terminal is different from the PCIG information or PCIG group information stored in the network entity. Accordingly, the terminal can request the PCIG information or PCIG group information from the network entity as in operation 940.

[0143] In addition, in one example, when a terminal is scheduled to connect to an NTN cell in a terrestrial network, if it is determined that it is advantageous for the terminal to receive PCIG information or PCIG group information from a TN cell in a stable terrestrial network rather than an unstable NTN cell, the terminal may request PCIG information or PCIG group information from a network entity as in operation 940.

[0144] Afterwards, operations 950 to 970 of the terminal can operate in the same way as operations 910 to 930 described in (A) of FIG. 9.

[0145] As described above, the terminal receives PCIG information or PCIG group information from a network entity and can recognize the PCIG information or PCIG group information mapped to the PCI calculated by the terminal as identical to the network entity.

[0146] FIG. 10 is a flowchart illustrating the operation of a terminal according to one embodiment of the present disclosure.

[0147] In operation 1010, in a non-terrestrial network system, the terminal may receive a first PCI for a first cell from a first NTN base station. The first cell may represent an NTN cell (or a non-terrestrial satellite cell) to which the terminal is connected in an RRC CONNECTED state or is camped in an RRC IDLE state. Additionally, the first NTN base station may refer to a base station that relays a first satellite forming an NTN cell with the terminal in the NTN cell.

[0148] An NTN cell may be a quasi-earth fixed cell. A quasi-earth fixed cell refers to a satellite cell formed in a specific area of ​​the Earth's surface. Since the satellites described in this disclosure (e.g., LE0 satellites and MEO satellites) move relative to the Earth's surface, they cannot continuously form a cell in a specific area. This disclosure illustrates a case where a quasi-earth fixed cell is formed in a specific area even if the satellite moves relative to the ground by rotating the antenna of the beam forming the satellite cell. Therefore, the PCI in the NTN cell described in this disclosure allows the satellite forming the NTN cell to change continuously over time. That is, the PCI in the NTN cell is not in a fixed form but can be dynamically changed by the network entity. If the satellite forming the NTN cell currently connected to the terminal changes, the PCI can be changed to the PCI set by the network entity for the satellite to be changed.

[0149] In one example, the entity receiving the first PCI at the terminal is not limited to the first NTN base station and may receive it from network entities such as a satellite, MNO, or SNO.

[0150] In operation 1020, the terminal may receive a second PCI for the first cell from a second NTN base station. The second NTN base station may refer to a base station that relays a second satellite forming the first cell. At this time, the second satellite may refer to a satellite that subsequently forms a spot beam forming the first cell when the first satellite forming the first cell in operation 1010 moves and can no longer form a spot beam forming the first cell.

[0151] In one example, the entity receiving the second PCI at the terminal is not limited to the second NTN base station and may receive it from network entities such as a satellite, MNO, or SNO.

[0152] In operation 1030, the terminal can calculate a PCIG (PCI gap) corresponding to the difference between the first PCI and the second PCI. The PCIG may represent the absolute value of the difference between the PCI value received later and the PCI value received later. For example, the terminal can calculate the PCIG as |ij|, which is the absolute value of the difference between the first PCI value i and the second PCI value j.

[0153] In one example, PCI max If additionally configured, the terminal [according to the aforementioned Equation 1] calculates the absolute value of the difference between the PCI received at time t and the PCI received at time t+1 as PCI. max The remainder after division can be identified as PCIG.

[0154] In operation 1040, the terminal can identify first cell information corresponding to the PCIG within the PCIG information.

[0155] In one example, the PCIG information may include metadata mapped to the PCIG for each. In one example, the metadata may include NTN cell information (or cell metadata). The NTN cell information may be information such as payload type, polarization type, satellite orbit type, satellite change type, satellite altitude, and MNO, which can be identified in the PCIG information. Specifically, the PCIG information may include NTN cell information such as payload type, polarization type, satellite orbit type, satellite change type, satellite altitude, and MNO. For example, the PCIG information may include the information of [Table 4] mentioned above.

[0156] Meanwhile, PCIG information may be information stored in advance in the terminal, or information received by the terminal from a network entity (e.g., satellite, RAN (radio access network), core network (CN), OAM (operations, administration, and maintenance), telecom server, UE vendor server, TN server, etc.). When the terminal receives PCIG information from a network entity, the terminal may obtain PCIG information by receiving an update message of PCIG information from the network entity. In one example, the terminal may update existing information by receiving PCIG information that is not stored in advance from the network entity, or by receiving updated PCIG information from the network entity when there is PCIG information stored in advance but it is not the latest information.

[0157] According to one embodiment of the present disclosure, a terminal may perform additional operations (or functions) related to an NTN cell based on identified first cell information. For example, if the identified first cell information includes information that there exists a cell of a terrestrial network that overlaps with the NTN cell, the terminal may decide to perform a search for a terrestrial network cell. Additionally, if the identified cell information includes the proportion of overlap of the terrestrial network cell, the terminal may perform an operation to adjust the search interval for the terrestrial network cell.

[0158] FIG. 11 is a flowchart illustrating the operation of a terminal according to an embodiment of the present disclosure. Operations 1110 to 1140 are identical to operations 1010 to 1040 of FIG. 10, so a description is omitted.

[0159] In operation 1150, the terminal can identify a PCIG group (or PCIGG (PCIG group)) corresponding to the PCIG calculated using the first PCI and the second PCI in operation 1130. The PCIG group may be a parameter representing a certain range of the PCIG. For example, in Example 1 of FIG. 5, the PCIG group may include a first PCIG group in which the PCIG value is 1 to 200, a second PCIG group in which the PCIG value is 201 to 400, and a third PCIG group in which the PCIG value is 401 to 504. The terminal can additionally identify metadata mapped to the recognized PCIG group within the PCIG group information. Accordingly, the terminal can perform additional operations based on the metadata mapped to the PCIG group.

[0160] In operation 1160, the terminal can identify second cell information corresponding to the PCIG group identified in operation 1150 within the PCIG group information.

[0161] In one example, the second cell information may represent NTN cell information to which the terminal is connected, similar to the first cell information. The second cell information may be stored in the terminal by being included in PCIG information or PCIG group information.

[0162] According to one embodiment of the present disclosure, the information included in the PCIG group information may include, for example, information included in the PCIG information as well as the information shown in Example 1 or Example 2 of FIG. 5. For example, the PCIG group information may include cell information or satellite information such as payload type, polarization type, satellite orbit type, satellite change type, satellite altitude, and MNO.

[0163] In one example, PCIG group information may be stored in advance when the terminal is manufactured. Alternatively, the terminal may obtain PCIG group information by receiving an update message for PCIG group information from a network entity. The terminal may update existing information by receiving PCIG group information that is not stored in advance from a network entity, or by receiving updated PCIG group information from a network entity if there is pre-stored PCIG group information but it is not the latest information. In this case, the network entity may include a satellite, RAN, core network (CN), OAM, telecom server, UE vendor server, TN server, etc.

[0164] FIG. 12 is a flowchart illustrating the operation of a base station according to an embodiment of the present disclosure. In this case, the base station may refer to an NTN base station that relays the terminal to a satellite for an NTN cell to which the terminal is connected.

[0165] In operation 1210, the base station may transmit an update message regarding PCIG information to the terminal. Additionally, the base station may transmit an update message regarding PCIG group information as well as PCIG information.

[0166] In one example, a PCIG update message or a PCIG group update message may include a PCIG (or PCIG group) description, a PCIG (or PCIG group) value, information corresponding to the PCIG (or PCIG group) value, etc. In one example, a PCIG update message or a PCIG group update message may include information requesting to update PCIG information or PCIG group information.

[0167] According to one embodiment of the present disclosure, a base station may transmit an update message regarding PCIG information or PCIG group information after receiving a message from a terminal requesting PCIG information or PCIG group information. In one example, if a problem occurs between the PCIG value calculated based on the PCI received from the NTN cell to which the terminal is connected and the actual operation performed, it may be recognized that the PCIG information or PCIG group information stored in the terminal differs from the PCIG information or PCIG group information stored in the network entity. Accordingly, the terminal may request PCIG information or PCIG group information from the base station. Additionally, in one example, if the terminal is scheduled to connect to an NTN cell from a terrestrial network, and it is determined that it is advantageous for the terminal to receive PCIG information or PCIG group information from a stable TN cell of the terrestrial network rather than an unstable NTN cell, the terminal may request PCIG information or PCIG group information from the base station. Accordingly, the base station may transmit an update message regarding PCIG information or PCIG group information to the terminal.

[0168] In one example, the entity sending update messages of PCIG information or PCIG group information to the terminal may be a network entity such as a base station, a satellite, a core network (CN), an OAM (operations, administration, and maintenance), a telecom server, a UE vendor server, a TN server, etc.

[0169] In one example, a terminal that receives an update message from a base station in operation 1210 can update PCIG information or PCIG group information based on the information included in the update message. In one example, if there is pre-stored PCIG information or PCIG group information, the terminal can change the existing PCIG information or PCIG group information to the PCIG information or PCIG group information received in operation 1210.

[0170] In operation 1220, the base station may receive an update completion message from the terminal. The update completion message may be a message in response to the update message transmitted in operation 1210. The PCIG or PCIG group update completion message may include information about PCIG information or PCIG group information that the terminal updated based on the message received in operation 1210.

[0171] In operation 1230, the base station may transmit a PCI for the first cell to the terminal. Operation 1230 may be an operation in which the NTN base station transmits a PCI to the terminal, such as the operation 1010 or operation 1020 of FIG. 10, or the operation 1110 or operation 1120 of FIG. 11.

[0172] FIG. 13 illustrates the structure of a terminal (1300) according to one embodiment of the present disclosure.

[0173] The configuration exemplified in FIG. 13 can be understood as a configuration of a terminal (1300). Terms such as '...part', '...unit' used below refer to a unit that processes at least one function or operation, and this can be implemented as hardware or software, or a combination of hardware and software.

[0174] Referring to FIG. 13, the terminal (1300) includes a communication unit (1310), a storage unit (1320), and a control unit (1330).

[0175] The communication unit (1310) performs functions for transmitting and receiving signals through a wireless channel. For example, the communication unit (1310) performs a conversion function between a baseband signal and a bit sequence according to the physical layer specifications of the system. For example, when transmitting data, the communication unit (1310) generates complex symbols by encoding and modulating the transmitted bit sequence. Also, when receiving data, the communication unit (1310) restores the received bit sequence by demodulating and decoding the baseband signal. Additionally, the communication unit (1310) upconverts the baseband signal into an RF band signal and transmits it through an antenna, and downconverts the RF band signal received through the antenna into a baseband signal. For example, the communication unit (1310) may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, etc.

[0176] Additionally, the communication unit (1310) may include a plurality of transmission and reception paths. Furthermore, the communication unit (1310) may include an antenna unit. The communication unit (1310) may include at least one antenna array composed of a plurality of antenna elements. In terms of hardware, the communication unit (1310) may be composed of digital circuits and analog circuits (e.g., RFIC (radio frequency integrated circuit)). Here, the digital circuits and analog circuits may be implemented as a single package. Additionally, the communication unit (1310) may include a plurality of RF chains. The communication unit (1310) may perform beamforming. The communication unit (1310) may apply beamforming weights to the signal to be transmitted or received in order to impart directionality according to the settings of the control unit (1330). According to one embodiment, the communication unit (1310) may include an RF (radio frequency) block (or RF unit). The RF block may include a first RF circuitry associated with the antenna and a second RF circuitry associated with baseband processing. The first RF circuitry may be referred to as RF-A (antenna). The second RF circuitry may be referred to as RF-B (baseband).

[0177] Additionally, the communication unit (1310) can transmit and receive signals. To this end, the communication unit (1310) may include at least one transceiver. The communication unit (1310) can receive downlink signals. The downlink signal may include a synchronization signal (SS), a reference signal (RS) (e.g., DM (demodulation)-RS, PTRS (phase tracking reference signal)), system information (e.g., MIB, SIB, RMSI (remaining system information), OSI (other system information)), a configuration message, control information, or downlink data. Additionally, the communication unit (1110) may transmit an uplink signal. The uplink signal may include a random access related signal (e.g., a random access preamble (RAP) (or Msg1 (message 1)), Msg3 (message 3)), a reference signal (e.g., SRS (sounding reference signal), DMRS, PTRS), or a power headroom report (PHR).

[0178] Additionally, the communication unit (1310) may include different communication modules to process signals of different frequency bands. Furthermore, the communication unit (1310) may include multiple communication modules to support multiple different wireless access technologies. For example, different wireless access technologies may include Bluetooth Low Energy (BLE), Wi-Fi (Wireless Fidelity), WiGig (WiFi Gigabyte), cellular networks (e.g., LTE (Long Term Evolution), NR (new radio), etc. Additionally, different frequency bands may include super high frequency (SHF) bands (e.g., 2.5 GHz, 5 GHz) and millimeter wave bands (e.g., 38 GHz, 60 GHz, etc.). Additionally, the communication unit (1310) may use the same type of wireless access technology on different frequency bands (e.g., unlicensed band for LAA (licensed Assisted Access), CBRS (citizens broadband radio service) (e.g., 3.5 GHz)).

[0179] The communication unit (1310) transmits and receives signals as described above. Accordingly, all or part of the communication unit (1310) may be referred to as a 'transmitter', a 'receiver', or a 'transmitter / receiver'. Additionally, in the following description, transmission and reception performed via a wireless channel are used to mean that processing as described above is performed by the communication unit (1310).

[0180] The storage unit (1320) stores data such as basic programs, application programs, and setting information for the operation of the terminal (1300). The storage unit (1320) may be composed of volatile memory, non-volatile memory, or a combination of volatile memory and non-volatile memory. Additionally, the storage unit (1320) provides the stored data upon the request of the control unit (1330).

[0181] The control unit (1330) controls the overall operations of the terminal (1300). For example, the control unit (1330) transmits and receives signals through the communication unit (1310). Additionally, the control unit (1330) writes and reads data to and from the storage unit (1320). Furthermore, the control unit (1330) can perform the functions of the protocol stack required by the communication standard. To this end, the control unit (1330) may include at least one processor. The control unit (1330) may include at least one processor or microprocessor, or may be part of a processor. Additionally, part of the communication unit (1310) and the control unit (1330) may be referred to as CP. The control unit (1330) may include various modules for performing communication. According to various embodiments, the control unit (1330) may control the terminal to perform operations according to various embodiments.

[0182] FIG. 14 illustrates the structure of a base station (1400) according to one embodiment of the present disclosure.

[0183] Referring to FIG. 14, the base station (1400) includes a communication unit (1410), a storage unit (1420), and a control unit (1430).

[0184] The communication unit (1410) performs functions for transmitting and receiving signals through a wireless channel. For example, the communication unit (1410) performs a conversion function between a baseband signal and a bit sequence according to the physical layer specifications of the system. For example, when transmitting data, the communication unit (1410) generates complex symbols by encoding and modulating the transmitted bit sequence. Also, when receiving data, the communication unit (1410) restores the received bit sequence by demodulating and decoding the baseband signal. Additionally, the communication unit (1410) upconverts the baseband signal into an RF (radio frequency) band signal and transmits it through an antenna, and downconverts the RF band signal received through the antenna into a baseband signal.

[0185] To this end, the communication unit (1210) may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a digital-to-analog converter (DAC), an analog-to-digital converter (ADC), etc. Additionally, the communication unit (1410) may include a plurality of transmission and reception paths. Furthermore, the communication unit (1410) may include at least one antenna array composed of a plurality of antenna elements. In terms of hardware, the communication unit (1410) may be composed of a digital unit and an analog unit, and the analog unit may be composed of a plurality of sub-units depending on operating power, operating frequency, etc.

[0186] The communication unit (1410) can transmit and receive signals. To this end, the communication unit (1410) may include at least one transceiver. For example, the communication unit (1410) can transmit a synchronization signal, a reference signal, system information, a message, control information, or data. Additionally, the communication unit (1410) can perform beamforming.

[0187] The communication unit (1410) transmits and receives signals as described above. Accordingly, all or part of the communication unit (1410) may be referred to as a 'transmitter', a 'receiver', or a 'transmitter / receiver'. Furthermore, in the following description, transmission and reception performed via a wireless channel are used to mean that processing as described above is performed by the communication unit (1410).

[0188] The storage unit (1420) stores data such as basic programs, application programs, and configuration information for the operation of the base station. The storage unit (1420) may include memory. The storage unit (1420) may be composed of volatile memory, non-volatile memory, or a combination of volatile memory and non-volatile memory. Additionally, the storage unit (1420) provides the stored data upon the request of the control unit (1430).

[0189] The control unit (1430) controls the overall operations of the base station (1400). For example, the control unit (1430) transmits and receives signals through the communication unit (1410). In addition, the control unit (1430) writes and reads data to and from the storage unit (1420). Furthermore, the control unit (1430) can perform the functions of a protocol stack required by the communication standard. To this end, the control unit (1430) may include at least one processor.

[0190] The configuration of the base station (1400) shown in FIG. 14 is merely one example of a base station, and the examples of base stations for performing various embodiments of the present disclosure are not limited to the configuration shown in FIG. 14. That is, depending on various embodiments, some configurations may be added, deleted, or changed.

[0191] In FIG. 14, the base station (1400) is described as a single entity, but the present disclosure is not limited thereto. According to various embodiments of the present disclosure, the base station (1400) may be implemented to form an access network having a distributed deployment as well as an integrated deployment. According to one embodiment, the base station may be distinguished into a central unit (CU) and a digital unit (DU), wherein the CU may be implemented to perform upper layer functions (e.g., packet data convergence protocol, RRC) and the DU may be implemented to perform lower layer functions (e.g., medium access control (MAC), physical (PHY)). The DU of the base station may form beam coverage on a wireless channel.

[0192] FIG. 15 illustrates the structure of a network entity (1500) according to one embodiment of the present disclosure.

[0193] A network entity according to one embodiment of the present disclosure may include a processor (1520) that controls the overall operation of the network entity, a transceiver (1500) including a transmitter and a receiver, and a memory (1510). Of course, it is not limited to the above examples, and the network entity may include more configurations than the configuration shown in FIG. 15, or fewer configurations.

[0194] According to one embodiment of the present disclosure, the transmitting and receiving unit (1500) may transmit and receive a signal with at least one of other network entities or terminals. The signal transmitted and received with at least one of other network entities or terminals may include control information and data.

[0195] According to one embodiment of the present disclosure, the processor (1520) can control a network entity to perform any one of the above-described embodiments. Meanwhile, the processor (1520), memory (1510), and transceiver (1500) do not necessarily have to be implemented as separate modules, and can be implemented as a single component in the form of a single chip. Also, the processor (1520) and the transceiver (600) can be electrically connected. Additionally, the processor (1520) may be an Application Processor (AP), a Communication Processor (CP), a circuit, an application-specific circuit, or at least one processor.

[0196] According to one embodiment of the present disclosure, the memory (1510) may store data such as a basic program, an application program, and configuration information for the operation of a network entity. In particular, the memory (1510) provides the stored data upon request by the processor (1520). The memory (1510) may be composed of a storage medium or a combination of storage media such as ROM, RAM, a hard disk, a CD-ROM, and a DVD. Additionally, the memory (1510) may be a plurality of. Furthermore, the processor (1520) may perform the aforementioned embodiments based on a program for performing the aforementioned embodiments of the present disclosure stored in the memory (1510).

[0197] Meanwhile, the embodiments of the present invention disclosed in this specification and drawings are merely specific examples provided to facilitate the explanation of the technical content of the present invention and to aid in understanding the invention, and are not intended to limit the scope of the invention. That is, it is obvious to those skilled in the art that other variations based on the technical concept of the present invention are possible. Furthermore, each of the above embodiments may be combined and operated together as needed.

[0198] As described above, a method performed by a terminal (user equipment) in a wireless communication system using a non-terrestrial network (NTN) according to various embodiments disclosed in this document may include the steps of receiving a first physical cell ID (PCI) for a first cell from a first NTN base station, receiving a second PCI for a first cell from a second NTN base station, calculating a PCI gap (PCI Gap) corresponding to the difference between the first PCI and the second PCI, and identifying first cell information corresponding to the calculated PCIG within the PCIG information.

[0199] According to various embodiments disclosed in this document, the method may further include the steps of identifying a PCIG group representing a range of PCIGs associated with a calculated PCIG, and identifying second cell information corresponding to the identified PCIG group within the PCIG group information.

[0200] According to various embodiments disclosed in this document, the method may further include the step of identifying a function indicated by first cell information and second cell information, and the step of performing the identified function.

[0201] According to various embodiments disclosed in this document, PCIG information may include at least one of a payload type, a polarization type, a satellite orbit type, a satellite change type, or a satellite altitude.

[0202] According to various embodiments disclosed in this document, PCIG group information may include at least one of a payload type, polarization type, satellite orbit type, satellite change type, satellite altitude, and MNO (mobile network operator).

[0203] According to various embodiments disclosed in this document, the method comprises the step of determining whether to search for a second cell based on identified first cell information, and, if the search for the second cell is determined, the step of determining the search interval of the second cell based on the first cell information, wherein the second cell may represent a cell of a ground network adjacent to the first cell.

[0204] According to various embodiments disclosed in this document, the method may include the steps of receiving an update message for PCIG information from a first NTN base station or a second NTN base station, modifying the PCIG information based on the update message, and transmitting an update completion message to the first NTN base station or the second NTN base station in response to the update message.

[0205] According to various embodiments disclosed in this document, the step of receiving an update message may include the step of transmitting a request message requesting PCIG information to a first NTN base station or a second NTN base station.

[0206] According to various embodiments disclosed in this document, the terminal may be connected to the first cell in an RRC connected state or camped on with the first cell in an RRC idle state.

[0207] As described above, in a wireless communication system using a non-terrestrial network (NTN) according to various embodiments disclosed in this document, a terminal (user equipment) includes a transceiver and a processor coupled to the transceiver, and the processor may be configured to receive a first physical cell ID (PCI) for a first cell from a first NTN base station and receive a second PCI for a first cell from a second NTN base station, calculate a PCI gap (PCI Gap) corresponding to the difference between the first PCI and the second PCI, and identify first cell information corresponding to the calculated PCI G within the PCI G information.

[0208] According to various embodiments disclosed in this document, the processor may be further configured to identify a PCIG group representing a range of PCIGs associated with a calculated PCIG, and to identify second cell information corresponding to the identified PCIG group within the PCIG group information.

[0209] According to various embodiments disclosed in this document, the processor may be further configured to identify the function indicated by the first cell information and the second cell information, and to perform the identified function.

[0210] According to various embodiments disclosed in this document, PCIG information may include at least one of a payload type, a polarization type, a satellite orbit type, a satellite change type, or a satellite altitude.

[0211] According to various embodiments disclosed in this document, PCIG group information may include at least one of a payload type, polarization type, satellite orbit type, satellite change type, satellite altitude, and MNO (mobile network operator).

[0212] According to various embodiments disclosed in this document, a processor is configured to determine whether to search for a second cell based on identified first cell information, and if the search for the second cell is determined, to determine the search interval of the second cell based on the first cell information, and the second cell may represent a cell of a terrestrial network adjacent to the first cell.

[0213] According to various embodiments disclosed in this document, a processor may be configured to receive an update message for PCIG information from a network entity, modify the PCIG information based on the update message, and send an update completion message to the network entity in response to the update message.

[0214] According to various embodiments disclosed in this document, a processor may be configured to receive an update message by sending a request message to a network entity requesting PCIG information.

[0215] According to various embodiments disclosed in this document, the terminal may be connected to the first cell in an RRC connected state or camped on with the first cell in an RRC idle state.

[0216] As described above, a method performed by a base station in a wireless communication system using a non-terrestrial network (NTN) according to various embodiments disclosed in this document comprises the steps of: transmitting an update message for PCIG information to a terminal (user equipment); receiving an update completion message from the terminal in response to the update message; and transmitting a physical cell ID (PCI) for a first cell to the terminal, wherein the PCI is used to calculate the PCIG (PCI gap), and the PCIG can be used to identify the first cell information corresponding to the PCIG within the PCIG information.

[0217] According to various embodiments disclosed in this document, the first cell information may include at least one of a payload type, a polarization type, a satellite orbit type, a satellite change type, or a satellite altitude.

[0218] As described above, in a wireless communication system according to various embodiments disclosed in this document, a base station comprises a transceiver and a processor coupled to the transceiver, and the processor is configured to transmit an update message for PCIG information to a terminal (user equipment), receive an update completion message from the terminal in response to the update message, and transmit a physical cell ID (PCI) for a first cell to the terminal, wherein the PCI is used to calculate a PCIG (PCI gap), and the PCIG can be used to identify first cell information corresponding to the PCIG within the PCIG information.

Claims

1. A method performed by a terminal (user equipment) in a wireless communication system using a non-terrestrial network (NTN), A step of receiving a first PCI (physical cell ID) for a first cell from a first NTN base station; A step of receiving a second PCI for the first cell from a second NTN base station; A step of calculating a PCIG (PCI gap) corresponding to the difference between the first PCI and the second PCI; and A method comprising the step of identifying first cell information corresponding to the calculated PCIG within the PCIG information.

2. In claim 1, the method is, A step of identifying a PCIG group representing a range of PCIGs associated with the above-calculated PCIG; A method further comprising the step of identifying second cell information corresponding to the identified PCIG group within the PCIG group information.

3. In claim 2, the method is, A step of identifying the function indicated by the first cell information and the second cell information; and A method comprising further steps of performing the above-mentioned identified function.

4. In Claim 2, The above PCIG information includes at least one of a payload type, a polarization type, a satellite orbit type, a satellite change type, or a satellite altitude, in a method.

5. In claim 1, the method is, A step of determining whether to search for a second cell based on the first cell information identified above; and When the search of the second cell is determined, the method includes the step of determining the search interval of the second cell based on the first cell information. A method in which the second cell represents a cell of a ground network adjacent to the first cell.

6. In a wireless communication system using a non-terrestrial network (NTN), regarding a terminal (user equipment), At least one transceiver; At least one processor communicatively coupled to the above at least one transceiver; and It includes at least one memory that is communicationally coupled to the above at least one processor and stores instructions, and The above instructions are executed individually or in any combination by the above at least one processor, so that the terminal: Receive the first PCI (physical cell ID) for the first cell from the first NTN base station, and A step of receiving a second PCI for the first cell from a second NTN base station; Calculate the PCIG (PCI gap) corresponding to the difference between the first PCI and the second PCI, and A terminal that identifies first cell information corresponding to the calculated PCIG within the PCIG information.

7. In claim 6, the above commands are the terminal: Identify a PCIG group representing the range of PCIGs associated with the above-calculated PCIG, and A terminal further configured to identify second cell information corresponding to the identified PCIG group within the PCIG group information.

8. In claim 7, the above commands are the terminal: Identifying the functions indicated by the first cell information and the second cell information, and A method further configured to perform the above-identified function.

9. In Claim 7, The above PCIG information includes at least one of a payload type, a polarization type, a satellite orbit type, a satellite change type, or a satellite altitude, in a terminal.

10. In Claim 7, A terminal comprising at least one of the above PCIG group information, a payload type, a polarization type, a satellite orbit type, a satellite change type, a satellite altitude, or a mobile network operator (MNO).

11. In claim 6, the above commands are the terminal: Determining whether to search for a second cell based on the first cell information identified above, and When the search of the second cell is determined, the search interval of the second cell is determined based on the information of the first cell, and The above second cell is a terminal representing a cell of a terrestrial network adjacent to the above first cell.

12. In claim 6, the above commands are the terminal: Receive an update message regarding the above PCIG information from a network entity, and Modify the PCIG information based on the above update message, A terminal configured to send an update completion message to the above network entity in response to the above update message.

13. In claim 11, the above commands are the terminal: A terminal configured to receive the update message by sending a request message requesting the PCIG information to the above network entity.

14. A method performed by a base station in a wireless communication system using a non-terrestrial network (NTN), A step of transmitting an update message regarding PCIG information to a terminal (user equipment); A step of receiving an update completion message from the terminal in response to the update message; and The method includes the step of transmitting a physical cell ID (PCI) for a first cell to the terminal, and The above PCI is used to calculate the PCIG (PCI gap), and A method in which the above PCIG is used to identify first cell information corresponding to the PCIG within the above PCIG information.

15. In a base station of a wireless communication system using a non-terrestrial network (NTN), At least one transceiver; At least one processor communicatively coupled to the above at least one transceiver; and It includes at least one memory that is communicationally coupled to the above at least one processor and stores instructions, and The above instructions are executed individually or in any combination by the above at least one processor, so that the base station: A step of transmitting an update message regarding PCIG information to a terminal (user equipment); A step of receiving an update completion message from the terminal in response to the update message; and The above terminal is instructed to transmit the PCI (physical cell ID) for the first cell, and The above PCI is used to calculate the PCIG (PCI gap), and The above PCIG is a base station used to identify first cell information corresponding to the PCIG within the above PCIG information.

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