Method and device for managing mobility of RRC idle / inactive state terminal for beam scheduling operation in non-terrestrial network

Abstract

A method performed by a terminal supporting a non-terrestrial network (NTN), according to one embodiment of the present disclosure, may comprise the steps of: receiving, from a network entity capable of configuring a NTN cell supporting beam scheduling, a system information block (SIB) including time information related to the activation and deactivation of the NTN cell supporting beam scheduling; determining activation and deactivation period information of a first NTN cell on the basis of the time information related to the activation and deactivation of the NTN cell supporting beam scheduling; and performing a radio resource control (RRC) idle state or inactive operation on the basis of the activation and deactivation period information of the first NTN cell.

Description

Method and device for managing mobility of RRC IDLE / INACTIVE STATE terminals for beam scheduling operation in non-terrestrial networks

[0001] The present disclosure relates to a method and device for terminals and network entities in a non-terrestrial network (NTN). More specifically, the present disclosure relates to a method and device for terminals and network entities supporting NTN to transmit and receive signals according to spot beam scheduling settings.

[0002] Looking back at the evolution of wireless communication over successive generations, technologies have primarily been developed for human-facing services such as voice, multimedia, and data. With the commercialization of 5G (5th-generation) communication systems, an explosive increase in connected devices is 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 equipment, and factory equipment. Mobile devices are expected to evolve into diverse form factors, including augmented reality glasses, virtual reality headsets, and holographic devices. In the 6th-generation (6G) era, efforts are being made to develop improved 6G communication systems to connect hundreds of billions of devices and objects and provide diverse services. For this reason, 6G communication systems are often referred to as "Beyond 5G" systems.

[0003] The 6G communication system, expected to be realized around 2030, will have a maximum transmission speed of terabytes per second (i.e., 1,000 gigabits per second) and a wireless latency of 100 microseconds (μsec). In other words, compared to 5G, the transmission speed in a 6G communication system will be 50 times faster, while the wireless latency will be reduced to one-tenth.

[0004] To achieve these high data rates and ultra-low latency, 6G communication systems are being considered for implementation in the terahertz band (e.g., from 95 gigahertz (GHz) to 3 terahertz (THz)). Compared to the millimeter wave (mmWave) band introduced in 5G, the terahertz band is expected to experience more severe path loss and atmospheric absorption, making it more crucial to ensure signal reach, or coverage, in this band. Key technologies to ensure coverage include radio frequency (RF) components, antennas, new waveforms that offer better coverage than orthogonal frequency division multiplexing (OFDM), beamforming, and multiple antenna transmission technologies such as massive multiple-input and multiple-output (MIMO), full-dimensional MIMO (FD-MIMO), array antennas, and large-scale antennas. In addition, new technologies such as metamaterial-based lenses and antennas, high-dimensional spatial multiplexing using orbital angular momentum (OAM), and reconfigurable intelligent surfaces (RIS) are being discussed to improve the coverage of terahertz band signals.

[0005] In addition, in order to improve frequency efficiency and system network, 6G communication systems are developing full duplex technology that utilizes the same frequency resources for uplink and downlink at the same time; network technology that integrates satellites and high-altitude platform stations (HAPS); network structure innovation technology that supports mobile base stations and enables optimization and automation of network operation; dynamic spectrum sharing technology through collision avoidance based on spectrum usage prediction; AI-based communication technology that utilizes artificial intelligence (AI) 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 with complexity that exceeds the limits of terminal computing capabilities by utilizing ultra-high-performance communication and computing resources (mobile edge computing (MEC), cloud, etc.). In addition, efforts are being made to further strengthen connectivity between devices, further optimize networks, promote softwareization of network entities, and increase the openness of wireless communications 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 use of data, and the development of technologies for maintaining privacy.

[0006] Research and development of these 6G communication systems are expected to enable a new level of hyper-connected experience through the hyper-connectivity of 6G communication systems, which encompass not only connections between things but also connections between people and things. Specifically, 6G communication systems are expected to enable 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 through enhanced security and reliability, will be applied in diverse fields such as industry, medicine, automobiles, and home appliances.

[0007] The purpose of the present disclosure is to propose a method for obtaining non-terrestrial network (NTN) cell information and an operation method in a radio resource control (RRC) idle / inactive state of a terminal according to spot beam scheduling settings.

[0008] The technical problems to be achieved in the embodiments of the present disclosure are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by a person having ordinary skill in the technical field to which the present disclosure belongs from the description below.

[0009] According to one embodiment of the present disclosure for achieving the above object, a method performed by a terminal supporting a non-terrestrial network (NTN) comprises the steps of: receiving, from a network entity capable of setting an NTN cell supporting beam scheduling, a system information block (SIB) including activation and deactivation-related time information of an NTN cell supporting beam scheduling; determining activation and deactivation period information of a first NTN cell based on the activation and deactivation-related time information of the NTN cell supporting beam scheduling; and performing a radio resource control (RRC) idle state or inactive operation based on the activation and deactivation period information of the first NTN cell.

[0010] According to one embodiment of the present disclosure for achieving the above object, a method performed by a network entity supporting a non-terrestrial network (NTN) comprises the steps of: generating a system information block including information related to activation and deactivation times of an NTN cell supporting beam scheduling; and transmitting the system information block including information related to activation and deactivation times of an NTN cell supporting the beam scheduling, wherein the activation and deactivation period information of a first NTN cell is based on the activation and deactivation time information of the NTN cell supporting beam scheduling, and a radio resource control (RRC) idle state or inactive operation is based on the activation and deactivation period information of the first NTN cell.

[0011] According to one embodiment of the present disclosure for achieving the above object, a terminal supporting a non-terrestrial network (NTN) comprises: a transceiver for transmitting and receiving a signal; and a control unit, wherein the control unit receives, from a network entity capable of setting an NTN cell supporting beam scheduling, a system information block (SIB) including activation and deactivation-related time information of an NTN cell supporting beam scheduling, and determines activation and deactivation period information of a first NTN cell based on the activation and deactivation-related time information of the NTN cell supporting beam scheduling, and performs a radio resource control (RRC) idle state or inactive operation based on the activation and deactivation period information of the first NTN cell.

[0012] According to one embodiment of the present disclosure for achieving the above object, a network entity supporting a non-terrestrial network (NTN) includes a transceiver for transmitting and receiving a signal; and a control unit, wherein the control unit generates a system information block including information related to activation and deactivation times of an NTN cell supporting beam scheduling, and transmits the system information block including information related to activation and deactivation times of an NTN cell supporting the beam scheduling, wherein the activation and deactivation period information of a first NTN cell is based on the activation and deactivation time information of the NTN cell supporting the beam scheduling, and a radio resource control (RRC) idle state or inactive operation is characterized in that it is based on the activation and deactivation period information of the first NTN cell.

[0013] According to various embodiments proposed in the present disclosure, a satellite, base station or terminal supporting a non-terrestrial network (NTN) can perform spot beam scheduling (spot beam hopping).

[0014] More specifically, when spot beam scheduling (spot beam hopping) technology is applied, power consumption can be reduced and the ping-pong effect can be prevented.

[0015] The effects that can be obtained from the present disclosure are not limited to the effects mentioned in the various embodiments, and other effects that are not mentioned can be clearly understood by a person having ordinary skill in the art to which the present disclosure belongs from the description below.

[0016] To more clearly explain the technical solutions of the embodiments proposed in this disclosure, drawings of the embodiments will be briefly introduced. The drawings below are for reference only and do not limit the present disclosure.

[0017] FIG. 1 is a diagram illustrating a next-generation mobile communication system to which the present disclosure can be applied.

[0018] FIG. 2 is a diagram illustrating the structure of a non-terrestrial network (NTN) to which the present disclosure can be applied.

[0019] FIG. 3 is a diagram illustrating an example of a non-terrestrial network (NTN) to which the present disclosure can be applied.

[0020] FIG. 4a is a diagram illustrating a classification method according to satellite functions of a non-terrestrial network (NTN) to which the present disclosure can be applied.

[0021] FIG. 4b is a diagram illustrating a classification method according to satellite functions of a non-terrestrial network (NTN) to which the present disclosure can be applied.

[0022] FIG. 5a is a diagram illustrating an earth fixed cell, a quasi-earth fixed cell, and an earth moving cell of a non-terrestrial network (NTN) to which the present disclosure can be applied.

[0023] FIG. 5b is a diagram illustrating an earth fixed cell, a quasi-earth fixed cell, and an earth moving cell of a non-terrestrial network (NTN) to which the present disclosure can be applied.

[0024] FIG. 5c is a diagram illustrating an earth fixed cell, a quasi-earth fixed cell, and an earth moving cell of a non-terrestrial network (NTN) to which the present disclosure can be applied.

[0025] FIG. 6 is a diagram for explaining spot beam scheduling and cell status according to one embodiment of the present disclosure.

[0026] FIG. 7 is a diagram illustrating a procedure for a terminal to obtain spot beam scheduling related information according to an embodiment of the present disclosure.

[0027] FIG. 8A is a diagram illustrating a method for a terminal to calculate activation and deactivation patterns of a non-terrestrial network (NTN) cell for which beam scheduling is set according to an embodiment of the present disclosure.

[0028] FIG. 8b is a diagram illustrating a method for a terminal to calculate activation and deactivation patterns of a non-terrestrial network (NTN) cell for which beam scheduling is set according to an embodiment of the present disclosure.

[0029] FIG. 9 is a flowchart illustrating a method for a terminal to maintain a radio resource control (RRC) idle and inactive state when the terminal is inactive due to beam scheduling settings of a non-terrestrial network (NTN) cell according to an embodiment of the present disclosure.

[0030] FIG. 10A is a diagram illustrating an operation in which a terminal maintains a radio resource control (RRC) idle and inactive state when the terminal is inactive due to beam scheduling settings of a non-terrestrial network (NTN) cell according to one embodiment of the present disclosure.

[0031] FIG. 10b is a diagram illustrating an operation in which a terminal maintains a radio resource control (RRC) idle and inactive state when the terminal is inactive due to beam scheduling settings of a non-terrestrial network (NTN) cell according to an embodiment of the present disclosure.

[0032] FIG. 11 is a flowchart illustrating a sequence for omitting physical downlink control channel (PDCCH) monitoring when a terminal is deactivated due to beam scheduling settings of a non-terrestrial network (NTN) cell according to an embodiment of the present disclosure.

[0033] FIG. 12 is a diagram illustrating a method for a terminal to omit monitoring of a physical downlink control channel (PDCCH) when the terminal is inactive due to beam scheduling settings of a non-terrestrial network (NTN) cell according to an embodiment of the present disclosure.

[0034] FIG. 13 is a flowchart illustrating a method for a terminal to delay transmission of uplink traffic when a non-terrestrial network (NTN) cell is inactive due to beam scheduling settings according to an embodiment of the present disclosure.

[0035] FIG. 14 is a diagram illustrating an operation of a terminal according to an embodiment of the present disclosure to delay transmission of uplink traffic when a non-terrestrial network (NTN) cell is inactive due to beam scheduling settings.

[0036] FIG. 15 is a flowchart illustrating a sequence for performing cell reselection when beam scheduling of a non-terrestrial network (NTN) cell is disabled due to a setting according to one embodiment of the present disclosure.

[0037] FIG. 16a is a diagram illustrating an operation of a terminal to suspend a random access procedure when beam scheduling of a non-terrestrial network (NTN) cell is disabled due to a setting according to an embodiment of the present disclosure.

[0038] FIG. 16b is a diagram illustrating an operation of a terminal to suspend a random access procedure when beam scheduling of a non-terrestrial network (NTN) cell is disabled due to a setting according to an embodiment of the present disclosure.

[0039] FIG. 17 is a flowchart illustrating a sequence of terminal operations according to an embodiment of the present disclosure.

[0040] FIG. 18 is a flowchart illustrating a sequence of network entity operations supporting a non-terrestrial network (NTN) according to one embodiment of the present disclosure.

[0041] FIG. 19 is a diagram illustrating the internal structure of a terminal according to an embodiment of the present disclosure.

[0042] FIG. 20 is a diagram illustrating the internal structure of a network entity supporting NTN according to one embodiment of the present disclosure.

[0043] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the attached drawings.

[0044] In describing the embodiments, descriptions of technical contents that are well known in the technical field to which the present disclosure belongs and are not directly related to the present disclosure are omitted.

[0045] This is to convey the gist of the present disclosure more clearly without obscuring it by omitting unnecessary explanations.

[0046] For the same reason, some components in the attached drawings are exaggerated, omitted, or schematically depicted. Furthermore, the dimensions of each component do not entirely reflect the actual size. Identical or corresponding components in each drawing are assigned the same reference numbers.

[0047] The advantages and features of the present disclosure and the methods for achieving them will become apparent with reference to the embodiments described in detail below together with the accompanying drawings.

[0048] However, the present disclosure is not limited to the embodiments disclosed below and may be implemented in various different forms. These embodiments are provided only to complete the composition of the present disclosure and to fully inform those skilled in the art of the present disclosure of the scope of the invention, and the present disclosure is defined only by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

[0049] At this time, it will be understood that each block of the processing flow diagrams and combinations of the flow diagrams can be performed by computer program instructions. These computer program instructions can be installed in a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing equipment, so that the instructions executed by the processor of the computer or other programmable data processing equipment create a means for performing the functions described in the flow diagram block(s). These computer program instructions can also be stored in a computer-available or computer-readable memory that can be directed to a computer or other programmable data processing equipment for implementation in a specific manner, so that the instructions stored in the computer-available or computer-readable memory can also produce a manufactured item that includes an instruction means for performing the functions described in the flow diagram block(s). Since the computer program instructions can also be installed on a computer or other programmable data processing device, a series of operational steps can be performed on the computer or other programmable data processing device to create a computer-executable process, and the instructions that cause the computer or other programmable data processing device to perform the steps for performing the functions described in the flowchart block(s) can also provide steps for performing the functions described in the flowchart block(s).

[0050] Additionally, each block may represent a module, segment, or portion of code that contains one or more executable instructions for performing a specific logical function(s). It should also be noted that in some alternative implementation examples, the functions described in the blocks may occur out of order. For example, two blocks depicted in succession may actually be executed substantially concurrently, or the blocks may sometimes be executed in reverse order, depending on their respective functions.

[0051] Here, the term '~ part' used in this embodiment means software or hardware components such as FPGA or ASIC, and the '~ part' performs certain roles. However, the '~ part' is not limited to software or hardware. The '~ part' may be configured to be on an addressable storage medium, and may be configured to play one or more processors. Accordingly, as an example, the '~ part' includes components such as software components, object-oriented software components, class components, and task components, processes, functions, properties, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functions provided within the components and '~ parts' may be combined into a smaller number of components and '~ parts', or further separated into additional components and '~ parts'. Additionally, components and '~parts' may be implemented to regenerate one or more CPUs within a device or secure multimedia card.

[0052] For the convenience of the following description, some terms and names defined in the 3rd generation partnership project (3GPP) standards (standards for 5G, NR, LTE, or similar systems) may be used. In addition, terms and names newly defined in next-generation communication systems (e.g., 6G, Beyond 5G systems) to which the present disclosure may be applied, or terms and names used in existing communication systems may be used. The use of such terms is not limited to the terms and names of the present disclosure, and may be equally applied to systems conforming to other standards, and may be modified into other forms without departing from the technical spirit of the present disclosure. Embodiments of the present disclosure may be easily modified and applied to other communication systems.

[0053] Additionally, it will be understood that singular expressions such as “a” and “the above” include plural expressions unless they clearly indicate otherwise in one embodiment of the present disclosure.

[0054] Additionally, in one embodiment of the present disclosure, terms including ordinal numbers, such as "first" and "second," may be used to describe various components, but the components are not limited by these terms. These terms are used solely to distinguish one component from another. For example, without departing from the scope of the present disclosure, a first component could be referred to as a "second component," and similarly, a second component could also be referred to as a "first component."

[0055] Additionally, in one embodiment of the present disclosure, the term and / or includes a combination of a plurality of related described items or any one of a plurality of related described items.

[0056] In addition, the terminology used in one embodiment of the present disclosure is only used to describe a specific embodiment and is not intended to limit the present disclosure. The singular expression includes plural expressions unless the context clearly indicates otherwise. In this specification, it should be understood that the terms "comprise" or "have" are intended to specify the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0057] Additionally, the terms “associated with” and “associated therewith” and their derivatives used in one embodiment of the present disclosure may mean include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicated with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, and the like.

[0058] Additionally, in the present disclosure, expressions such as "more than" and "less than" are used to determine whether a specific condition is satisfied or fulfilled. However, this is merely a description to express an example and does not exclude descriptions of more than or less than. Conditions described as "more than" may be replaced with "more than," conditions described as "less than" may be replaced with "less than," and conditions described as "more than and less than" may be replaced with "more than and less than."

[0059] Additionally, although the present disclosure describes embodiments using terms used in certain communication standards (e.g., long term evolution (LTE) and new radio (NR) defined by the 3rd generation partnership project (3GPP)), these are merely examples for illustrative purposes. The embodiments of the present disclosure can be easily modified and applied to other communication systems.

[0060] Before delving into the detailed description of this disclosure, examples of possible interpretations of some terms used herein are provided. However, it should be noted that the interpretations provided below are not limited to these examples.

[0061] In the present disclosure, a terminal (or communication terminal) is an entity that communicates with a base station or another terminal, and may be referred to as a node, UE (user equipment), NG UE (next generation UE), MS (mobile station), device, or terminal. In addition, the terminal may include at least one of a smartphone, a tablet PC, a mobile phone, a video phone, an e-book reader, a desktop PC, a laptop PC, a netbook computer, a PDA, a PMP (portable multimedia player), an MP3 player, a medical device, a camera, or a wearable device. In addition, the terminal may include at least one of a television, a DVD (digital video disk) player, an audio player, a refrigerator, an air conditioner, a vacuum cleaner, an oven, a microwave oven, a washing machine, an air purifier, a set-top box, a home automation control panel, a security control panel, a media box, a game console, an electronic dictionary, an electronic key, a camcorder, or an electronic picture frame.In addition, the terminal may include at least one of various medical devices (e.g., various portable medical measuring devices (such as blood glucose meters, heart rate monitors, blood pressure monitors, or body temperature monitors), magnetic resonance angiography (MRA), magnetic resonance imaging (MRI), computed tomography (CT), cameras, or ultrasound machines), navigation devices, global navigation satellite systems (GNSS), event data recorders (EDR), flight data recorders (FDR), automotive infotainment devices, electronic equipment for ships (e.g., navigation devices for ships, gyrocompasses, etc.), avionics, security devices, head units for vehicles, industrial or home robots, drones, ATMs for financial institutions, POSs (points of sales) for stores, or Internet of Things devices (e.g., light bulbs, various sensors, sprinkler devices, fire alarms, thermostats, streetlights, toasters, exercise equipment, hot water tanks, heaters, boilers, etc.). Additionally, the terminal may include various types of multimedia systems capable of performing communication functions. Meanwhile, the present disclosure is not limited to the above description, and the terminal may also be referred to by terms having the same or similar meaning.

[0062] In addition, in the present disclosure, the base station is an entity that communicates with a terminal and performs resource allocation of the terminal, and may have various forms and may be referred to as a BS (base station), a NodeB (NB), an NG RAN (next generation radio access network), an AP (access point), a TRP (transmission reception point), a wireless access unit, a base station controller, or a node on a network. Alternatively, it may be referred to as a CU (central unit) or a DU (distributed unit) depending on functional separation. Meanwhile, the present disclosure is not limited thereto, and the base station may be referred to by a term having the same or similar meaning.

[0063] Additionally, in the present disclosure, an RRC (radio resource control) message may be referred to as a higher level information, a higher level message, a higher level signal, a higher level signaling, a higher layer signaling, or a higher layer signaling, and the present disclosure is not limited thereto and may also be referred to by terms having the same or similar meaning.

[0064] Additionally, in the present disclosure, data may be referred to as user data, user plane (UP) data, or application data, or may be referred to by terms having the same or similar meaning as signals transmitted and received via a data radio bearer (DRB).

[0065] Additionally, in the present disclosure, the direction of data transmitted from a terminal may be referred to as uplink, and the direction of data transmitted to the terminal may be referred to as downlink. Accordingly, in the case of uplink transmission, the transmitter may refer to the terminal, and the receiver may refer to a base station or a specific network entity of the communication system. Alternatively, in the case of downlink transmission, the transmitter may refer to a base station or a specific network entity of the communication system, and the receiver may refer to the terminal.

[0066] FIG. 1 is a diagram illustrating a next-generation mobile communication system to which the present disclosure can be applied.

[0067] Referring to FIG. 1, a wireless access network of a next-generation mobile communication system may be composed of a next-generation base station (New Radio Node B, hereinafter referred to as NR gNB or NR base station) (110) and a next-generation radio core network (New Radio Core Network, NR CN) (105). A next-generation radio user equipment (NR UE or terminal) (115) may access an external network through the NR gNB (110) and the NR CN (105).

[0068] In Fig. 1, the NR gNB (110) may correspond to the eNB (Evolved Node B) of the existing LTE system. The NR gNB is connected to the NR UE (115) via a wireless channel and can provide a service superior to that of the existing Node B. In the next-generation mobile communication system, all user traffic can be serviced through a shared channel. Therefore, a device that collects status information such as the buffer status of UEs, available transmission power status, and channel status and performs scheduling is required, and the NR gNB (110) can be in charge of this. One NR gNB (110) can control multiple cells. In the next-generation mobile communication system, in order to implement ultra-high-speed data transmission compared to the current LTE, a bandwidth greater than the current maximum bandwidth may be applied. In addition, beamforming technology may be additionally grafted using Orthogonal Frequency Division Multiplexing (OFDM) as a wireless access technology. Additionally, an adaptive modulation and coding (AMC) method that determines a modulation scheme and channel coding rate according to the channel status of the terminal may be applied.

[0069] The NR CN (105) can perform functions such as mobility support, bearer setup, and QoS (quality of service) setup. The NR CN (105) is a device that is responsible for various control functions as well as mobility management functions for terminals and can be connected to multiple base stations. In addition, the next-generation mobile communication system can also be linked with the existing LTE system, and the NR CN (105) can be connected to the MME (125) through a network interface. The MME (125) can be connected to the existing base station, eNB (130). Meanwhile, the above-described next-generation mobile communication system is only an example of a communication system to which the present disclosure can be applied, and the present disclosure is not limited thereto. It goes without saying that the present disclosure can also be applied to a communication system having a different configuration from the above-described next-generation mobile communication system.

[0070] Meanwhile, mobile communication systems, including 3G, LTE (long-term evolution), and 5G, as described above, have provided connectivity for voice and data transmission and reception across a wide range of devices. Existing mobile communication systems have provided connectivity not only to portable personal devices such as mobile phones, smartphones, and personal tablets, but also to highly mobile devices such as lightweight and compact sensor devices, Internet of Things (IoT) devices, connected cars, drones, and Unmanned Aerial Vehicles (UAVs). The number and scope of devices connected through mobile communication systems are expected to continue expanding.

[0071] In the aforementioned mobile communication systems, when providing connectivity to devices, communication is performed via ground-based base stations using radio frequencies. While ground-based base stations offer the advantage of ease of installation and management, they are physically limited by their location on the ground. Due to these limitations, it is difficult to provide connectivity to devices located in the ocean or at sea (e.g., smartphones on ships or vessels), or in the air above a certain altitude (e.g., aircraft, high-altitude pseudo-satellites (HAPS), or hot air balloons), where ground-based base stations are difficult to install.

[0072] To overcome the physical limitations of existing mobile communication systems and expand connectivity from terrestrial to global, next-generation mobile communication systems such as 5G, Beyond 5G, and 6G are considering a communication system that combines terrestrial and satellite networks. While existing satellite networks have also provided connectivity via satellite, they have operated as independent networks separate from mobile communication systems, and communication with the satellite network was possible through dedicated terminals and devices. As a result, users of existing mobile communication systems required additional procedures, such as purchasing separate devices and registering as satellite network users. To alleviate this inconvenience and provide users with seamless, uninterrupted connectivity regardless of their location, satellite-integrated terrestrial network (STN) technology, or non-terrestrial network (NTN) technology, which combines a mobile communication system with a satellite network, is being discussed. By utilizing the satellite-integrated terrestrial network, connectivity can be provided not only to devices that can be connected on the ground, but also to devices at sea and in the air, and to devices in rural areas, rough terrain, and underdeveloped areas where terrestrial network installation was not easy, and where mobile communication infrastructure installation is difficult.

[0073] Below, we will specifically describe the Non-Terrestrial Network (NTN) technology field, which utilizes satellites in mobile communication systems to provide services in areas where communication services are unavailable (e.g., oceans, polar regions, remote areas, and airspace). The mobile communication technology may include not only 5G, which has adopted NTN as a standard, but also 6G, which is expected to be commercialized in 2030. In addition, the mobile communication technology described in the present disclosure includes mobile communication systems, satellite systems, and systems combining mobile communication and satellite systems to support NTN.

[0074] Meanwhile, the above-described communication system merely illustrates an example of a communication system to which the present disclosure can be applied, and the present disclosure is not limited thereto. In other words, the embodiments proposed in the present disclosure can be applied and implemented in various communication systems.

[0075] Hereinafter, with reference to FIGS. 2 and 3, the NTN considered in the present disclosure will be described in detail.

[0076] FIG. 2 is a diagram illustrating the structure of a non-terrestrial network (NTN) to which the present disclosure can be applied.

[0077] A non-terrestrial network (NTN) may include technologies that utilize satellites as relays to establish communication areas in areas where it is physically and / or economically impossible to install base stations for mobile communications.

[0078] Referring to FIG. 2, an NTN to which the present disclosure may be applied may be composed of a satellite (201), a terminal (202), a ground station (203), a base station (204), or a core network (205). Meanwhile, the NTN considered in the present disclosure is not limited to the configuration illustrated in FIG. 2, and may additionally include a network entity or a network node.

[0079] As illustrated in FIG. 2, the connection between the terminal (202) and the satellite (201) may be referred to as an access link, and the connection between the satellite (201) and the ground station (203) may be referred to as a feeder link. Meanwhile, the feeder link may refer to a connection between the satellite (201) and the base station (204), and when the ground station (203) and the base station (204) are combined into one, it may also refer to a connection between the combined ground station (203) and base station (204) and the satellite (201).

[0080] The core network (205) may include a user plane function (UPF) and a network function (NF) of NR or a satellite control server in satellite communications.

[0081] The altitudes of satellites that can be used in the above-mentioned satellites vary. Satellites that can be used in NTN can be divided into geostationary earth orbit (GEO), medium earth orbit (MEO), and low earth orbit (LEO) satellites, depending on the altitude of the mobile satellite.

[0082] GEO satellites are satellites that fly in a geostationary orbit at an altitude of approximately 36,000 km. Since their orbital period is the same as the Earth's rotation, they appear to be stationary over a single point in the sky when viewed from the Earth's surface. Due to the high satellite altitude, when communicating with geostationary satellites, the radio signals reaching the satellite are attenuated (path loss), resulting in relatively weaker wireless signals compared to terrestrial networks, and communication performance via wireless signals is also lower. Furthermore, the round-trip time between the satellite and devices and terminals on the ground is relatively long (approximately 500 milliseconds). Low-Earth orbit and medium-Earth orbit satellites exist at lower altitudes than geostationary satellites, so they experience less radio attenuation and have relatively strong wireless signals.

[0083] Meanwhile, compared to terrestrial networks, radio attenuation is still significant and radio signals are weak. Furthermore, unlike geostationary satellites, low-Earth orbit and medium-Earth orbit satellites travel at very high speeds relative to the Earth's surface (approximately 7.56 km from low-Earth orbit).

[0084] Meanwhile, LEO satellites, which exist approximately 200 to 2,000 km above the ground, are at a relatively low altitude compared to other satellites (e.g., GEO and MEO satellites). Due to the correlation between satellite altitude and latency, LEO satellites can guarantee relatively low latency. In other words, LEO satellites have the advantage of a short radio round-trip time, resulting in low latency. However, LEO satellites still experience significant radio attenuation and weaker radio signals compared to terrestrial networks. Furthermore, LEO satellites have a much faster speed (approximately 7.56 km / s at an altitude of 600 km) than other satellites (GEO and MEO satellites), resulting in constant frequency and / or time synchronization changes in stationary terminals or satellite antennas. Therefore, technologies that calculate and compensate for synchronization changes due to satellite mobility are key technologies in NTN.

[0085] FIG. 3 is a diagram illustrating an example of a non-terrestrial network (NTN) to which the present disclosure can be applied.

[0086] FIG. 3 is a diagram illustrating an example of applying NTN considered in the present disclosure to an NR system.

[0087] Referring to FIG. 3, the NTN may be composed of an NG-RAN (320), a 5G CN (370), and a data network (380). The NG-RAN (320) may be composed of a remote radio unit (330) and a gNB (360), and the remote radio unit (330) may be composed of a satellite (340) and an NTN gateway (350). When a terminal (310) accesses the NTN, it may transmit and receive data with the satellite (340), and the satellite (340) may transmit and receive data with the NTN gateway (350). The NTN gateway (350) may be connected to the gNB (360), and the gNB (360) may be connected to the data network (380) via the 5G CN (370).

[0088] Similar to synchronous communication technology in terrestrial networks, which synchronize terminals and base stations and transmit and receive data accordingly, NTN also synchronizes terminals and satellites, and transmits and receives data accordingly. Therefore, accurately aligning uplink and downlink synchronization between terminals and satellites can significantly impact communication performance. In one embodiment, downlink synchronization is achieved using a synchronization signal broadcast from the satellite, and uplink synchronization is achieved using a signal transmitted from the terminal.

[0089] According to one embodiment of the present disclosure, a satellite may broadcast a synchronization signal that provides synchronization information to a terminal at regular intervals. In an NTN to which the present disclosure may be applied, the satellite may broadcast a synchronization signal, such as a synchronization signal block (SSB), at regular intervals. The SSB may be composed of a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a physical broadcast channel (PBCH), and may include a signal providing synchronization information.

[0090] When a terminal initially accesses a cell or performs a handover from another cell, the terminal can obtain downlink synchronization information through information in a synchronization signal. Additionally, the terminal can obtain uplink synchronization information by performing a random access procedure (or RACH (random access channel) procedure) for the cell it initially accesses or the target cell for the handover.

[0091] Additionally, 3GPP NTN standardized the ability for terminals to self-correct their frequency and time synchronization before connecting to a base station via satellite. For a terminal to correct its frequency and time synchronization, it requires information about its location, mobility, satellite location, and satellite mobility.

[0092] Accordingly, the NTN standard allows terminals to utilize the Global Navigation Satellite System (GNSS) to measure their mobility and location information, and uses the measurement results for frequency and time synchronization correction and terminal mobility management. Furthermore, the terminals can receive satellite location or mobility information through broadcast messages transmitted to a base station connected to the satellite. These broadcast messages can include various information related to the satellite and the satellite cells formed by the satellite, including information on the satellite's position, velocity, and orbit.

[0093] 3GPP NR NTN defines System Information Block 19 (SIB19) as a broadcast message containing the above information. The message may include an Information Element (IE) containing orbital information, position information, and velocity information of a satellite connected to the base station transmitting the broadcast message, and may also include information related to satellite cell operation (e.g., satellite cell center position and diameter, surrounding satellite cell information).

[0094] Hereinafter, a non-terrestrial network (NTN) satellite, an NTN cell, a spot beam that can configure an NTN cell, and a spot beam scheduling technique according to an embodiment of the present disclosure will be described.

[0095] FIG. 4a and FIG. 4b are diagrams illustrating a classification method according to satellite function of a non-terrestrial network (NTN) to which the present disclosure can be applied.

[0096] In non-terrestrial networks (NTNs), satellites can be classified into transparent payload satellites and regenerative payload satellites according to their function.

[0097] Figure 4a is a diagram illustrating a transparent payload satellite. A transparent payload satellite can perform the functions of amplifying and forwarding signals transmitted from a terrestrial network. More specifically, a transparent payload satellite is equipped only with the functions of signal amplification, RF filtering, and frequency conversion, so it can perform the function of transmitting signals to the ground without processing, like a reflector / repeater. In this case, the satellite functions as a kind of relay node and cannot perform the functions of a base station, such as a DU (distributed unit) and / or CU (central unit) in NR.

[0098] Meanwhile, FIG. 4b is a diagram illustrating a regenerative payload satellite. A regenerative payload satellite may also be referred to as an On-Board Processing (OBP) payload satellite. In addition to signal amplification, RF filtering, and frequency conversion, a regenerative payload satellite may be equipped with encoding and / or decoding, encryption (modulation), and / or demodulation functions. That is, a regenerative payload satellite is equipped with a processor capable of processing and can thus function as a base station, such as a DU and / or CU. As illustrated in FIG. 4b, a regenerative payload satellite may only have a DU mounted on the satellite, while the CU may be included on the ground. Alternatively, a regenerative payload satellite may include both a DU and a CU.

[0099] The present disclosure is applicable to transparent payload satellites. Furthermore, the present disclosure is applicable to regenerative payloads in which only a DU is mounted on a satellite and the CU exists on the ground, and can also be applied to regenerative payload satellites in which both a DU and a CU are mounted on a satellite.

[0100] FIGS. 5A, 5B, and 5C are diagrams illustrating an earth fixed cell, a quasi-earth fixed cell, and an earth moving cell of a non-terrestrial network (NTN) to which the present disclosure can be applied.

[0101] In a non-terrestrial network (NTN), satellite cells, which are units that manage terminals, can be formed through spot beams emitted from satellites. Because low-Earth orbit satellites move at extremely high speeds in a fixed orbit, satellite coverage, which allows the satellite to communicate with terminals, also shifts with the satellite. Therefore, the method of operating a satellite cell can vary depending on how the satellite cell is configured.

[0102] According to one embodiment of the present disclosure, the operation method of satellite cells in NTN can be classified into earth fixed cells, quasi-earth fixed cells, and earth moving cells.

[0103] Referring to FIG. 5a, FIG. 5a is a diagram illustrating an earth fixed cell.

[0104] An earth-fixed cell is a method of forming a stationary satellite cell in a specific area via satellites. These cells are primarily formed by geostationary Earth orbit (GEO) satellites, whose orbital period is identical to the Earth's rotational period. Because a single satellite can form a cell for a relatively longer period of time than a mobile earth-fixed cell, an earth-fixed cell has the advantage of mitigating potential problems caused by the satellite's high mobility.

[0105] Figure 5b is a diagram illustrating a quasi-earth fixed cell, and Figure 5c is a diagram illustrating an earth moving cell.

[0106] Quasi-earth fixed cells and earth moving cells are methods used to form satellite cells in satellites whose orbital period and the Earth's rotation period are not the same, such as medium earth orbit (MEO) or low earth orbit (LEO).

[0107] A quasi-earth fixed cell is a method of forming a satellite cell in a fixed area on the Earth's surface. Unlike GEO satellites, which do not move relative to the Earth's surface and can form a fixed area 24 hours a day, LEO and MEO satellites move relative to the Earth's surface and cannot continuously form a cell in a fixed area. In such cases, a quasi-earth fixed cell rotates the antenna of the cell-forming beam to form a cell in a fixed area even if the satellite moves relative to the ground. Furthermore, if a satellite cell exists at a location beyond the maximum antenna rotation angle due to the satellite's movement and thus cannot form a cell, another satellite in the vicinity can take over and form a cell in that location.

[0108] Meanwhile, an earth moving cell is a cell mainly used in a satellite structure in which the antenna forming the cell of a MEO satellite or LEO satellite does not rotate (steering) but is always fixed in a direction perpendicular to the horizon, and the satellite cell also moves along with the movement of the satellite.

[0109] The present disclosure is applicable to both earth-moving cells, quasi-earth fixed cells, and earth-fixed cells. The present disclosure is not limited to a single embodiment, and the present disclosure may also be applied to satellite cells configured and operated in other ways.

[0110] FIG. 6 is a diagram for explaining beam scheduling and cell status according to one embodiment of the present disclosure.

[0111] In a non-terrestrial network (NTN) according to one embodiment of the present disclosure, a satellite cell (or NTN cell), which is a unit for managing terminals through a spot beam emitted from a satellite, may be formed. Hereinafter, this may be referred to as an "NTN cell supporting beam scheduling."

[0112] Hereinafter, an NTN cell supporting beam scheduling according to an embodiment of the present disclosure may mean a cell that switches between an active state and an inactive state when a satellite network operates a cell according to beam scheduling (which may be referred to as “spot beam scheduling”, “spot beam hopping”, or “beam hopping”). A satellite cell may be referred to interchangeably with the terms satellite cell managing a terminal in an NTN, cell supporting an NTN, satellite cell, NTN cell, or cell.

[0113] Spot beam scheduling or spot beam hopping according to one embodiment of the present disclosure may refer to an antenna array that operates only some spot beams. Hereinafter, spot beam scheduling may be used interchangeably with the terms spot beam hopping, beam scheduling, or beam hopping, and may also be referred to by terms having the same or similar meanings.

[0114] More specifically, when spot beam scheduling or spot beam hopping is applied, the satellite can dynamically operate the activation and deactivation states of specific spot beams over time without activating all of the spot beams that can be formed.

[0115] Spot beam scheduling technology can be applied to broadcast satellites centered on geostationary Earth orbit (GEO) satellites, as well as satellite networks utilizing low Earth orbit (LEO) satellites. Furthermore, spot beam scheduling or spot beam hopping technology can also be applied to satellites forming non-terrestrial networks for future 5G and / or 6G.

[0116] The main purposes of using spot beam scheduling or spot beam hopping are as follows:

[0117] First, it can reduce power consumption due to the limited available power of the satellite.

[0118] Satellites perform various operations based on the power generated by their onboard solar panels. Even for communications satellites, they can perform a variety of tasks simultaneously, in addition to their primary communication functions, such as satellite position measurement and calibration, attitude measurement and correction, telemetry for satellite status reporting, and communication with a Tracking and Control (TT&C) gateway. These operations must be performed solely with the power generated by their solar panels.

[0119] The available power of a satellite is limited in forming all possible spot beams in the area served by the satellite, and since hardware upgrades of the satellite are impossible, the limitation of available power is a problem that is unlikely to be resolved in the near future.

[0120] To maximize performance within this limited available power range, spot beam hopping technology can be applied. Specifically, by scheduling the timing of a satellite's spot beam formation so that only a subset of the spot beams are operated simultaneously, the number of simultaneously generated spot beams can be reduced, thereby reducing the power consumed by the satellite to form the spot beams.

[0121] Second, the system throughput of the satellite network can be improved.

[0122] Satellites serve large areas, and a single satellite can form dozens or hundreds of satellite cells.

[0123] Some satellite cells may be low-traffic cells, while others may be high-traffic cells. More specifically, low-traffic cells refer to cells with no or very low user counts and traffic, while high-traffic cells, which serve urban and / or sub-urban areas, may refer to cells with high user counts and traffic. If both low-traffic and high-traffic cells are formed during the same time period without spot beam scheduling, the low-traffic cells will waste power and radio resources, while the high-traffic cells may experience performance degradation due to a lack of power and radio resources.

[0124] Therefore, the spot beams that form cells with a large number of users and high traffic volume can be formed for a relatively long period of time, allowing the satellite's power and wireless resources to be used in those cells for a long period of time. Consequently, the total throughput of the satellite network can be improved.

[0125] Next, we will describe the status (or operation) of each cell when spot beam scheduling is set. When spot beam scheduling is set, a cell (or NTN cell) can repeatedly perform the operation of being activated and deactivated for a certain period of time according to beam scheduling. The period of repeating activation / deactivation of a cell for a certain period of time is called a duty cycle, and the corresponding duty cycle can be determined by the satellite network management server that manages the satellite network.

[0126] When a cell is in an active state (cell activation state), the cell can transmit and receive signals including a reference signal (e.g., a synchronization signal block (SSB)) and data. On the other hand, when a cell is in an inactive state (cell inactive state), the cell cannot transmit and receive signals including a reference signal and data.

[0127] In conventional NTN-based technology, if a terminal fails to receive a signal from the NTN at a regular interval or fails to receive a reference signal (SSB) that can synchronize with the cell, it is determined that the cell cannot be accessed. In the case of existing terrestrial networks, situations in which cell access is determined to be unavailable include situations in which signals are difficult to receive (e.g., underground, radio-shielded environment, etc.), and situations in which the terminal is powered on overseas, and corresponding actions are performed. In other words, in the terrestrial network, a situation in which SSB reception is unavailable is determined to be a situation in which the cell to which the terminal is connected has disappeared, and a cell reselection process is performed to search for a new accessible cell in the vicinity.

[0128] Since 3GPP NTN was designed without considering beam scheduling (or beam hopping), even if the signal is not received intentionally due to beam scheduling (or beam hopping), the terminal determines that the signal is not received intentionally and then performs cell reselection. During the cell reselection process, the terminal searches for neighboring cells, neighboring frequencies, and even neighboring RATs (Radio Access Technology), which is a power-intensive task from the terminal's perspective. In conclusion, the beam scheduling technology in NTN is intended to efficiently reduce the power consumption of the satellite, but it causes the problem of increased power consumption on the terminal's side.

[0129] In order to solve these problems, the present disclosure proposes a method for transmitting time information related to activation and deactivation of an NTN cell supporting beam scheduling through SIB (Figs. 7 to 8), an operation method for an RRC idle / inactive state of a terminal when deactivated due to satellite cell beam scheduling settings (Figs. 9 to 14), and a method for preventing unnecessary cell selection due to activation of another satellite cell when deactivated due to satellite cell beam scheduling settings (Figs. 15 to 16).

[0130] As an operation method of an RRC idle / inactive state, we propose a method for maintaining an RRC idle / inactive state of a terminal when it is inactive due to an NTN cell beam scheduling setting (Figs. 9 to 10), a method for skipping physical downlink control channel (PDCCH) paging in an idle / inactive state terminal when it is inactive due to an NTN cell beam scheduling setting (Figs. 11 to 12), and a method for delaying random access (RACH procedure) when uplink traffic occurs (Figs. 13 to 14).

[0131] FIG. 7 is a diagram illustrating a procedure for a terminal to obtain spot beam scheduling related information according to an embodiment of the present disclosure.

[0132] More specifically, FIG. 7 is a diagram for obtaining information related to activation and deactivation times of NTN cells supporting beam scheduling and explaining information included in the information related to activation and deactivation times of NTN cells supporting beam scheduling.

[0133] In a non-terrestrial network (NTN) according to one embodiment of the present disclosure, a satellite cell (or NTN cell), which is a unit for managing terminals through a spot beam emitted from a satellite, may be formed. Hereinafter, this may be referred to as an "NTN cell supporting beam scheduling."

[0134] Hereinafter, beam scheduling may be used interchangeably with the terms spot beam hopping, spot beam scheduling, or beam hopping, and may also be referred to by terms having the same or similar meaning.

[0135] According to one embodiment of the present disclosure, a terminal needs to obtain information related to spot beam scheduling of a satellite (or may be referred to as "information related to intentional activation and deactivation of NTN cells"). The present disclosure proposes a method for transmitting information related to intentional activation and deactivation of a non-terrestrial network (NTN) cell that is connectable to the terminal and waiting for the terminal. Intentional activation and deactivation may refer to activation and deactivation of an NTN cell due to beam scheduling settings.

[0136] The intentional activation and deactivation-related information of the NTN cell may include, but is not limited to, information on whether beam hopping or scheduling is applied (beam hopping applicable information), beam hopping pattern information, and beam hopping pattern-related time information (beam hopping timing-related information), and may include all information related to the time and period-related information of intentional activation and deactivation (hereinafter, referred to as “activation and deactivation time-related information of an NTN cell supporting beam scheduling”). In particular, the present disclosure proposes a method for transmitting activation and deactivation time-related information of an NTN cell supporting beam scheduling.

[0137] A device (or "entity") supporting a non-terrestrial network (NTN) according to an embodiment of the present disclosure may include a user-portable terminal (e.g., a user equipment (UE) such as a smartphone), a very small aperture terminal (VSAT) equipped with a parabolic antenna or phase array antenna, or a low-power device (e.g., an Internet of Things device or a sensor). For convenience of explanation, the following description will focus on terminals, but the scope of the present invention is not limited thereto.

[0138] The network entity supporting the above NTN may include both a satellite supporting NTN and a base station connected to a satellite supporting NTN. For example, in the case of a regenerative payload satellite that functions as a base station, the network entity supporting the NTN may refer to the regenerative payload satellite itself. In the case of a transparent payload satellite that functions as a relay, the network entity supporting the NTN may also refer to a base station on the ground.

[0139] The network entity supporting the above NTN is not limited to the above-described embodiment, and depending on the configuration of the satellite network, the network entity supporting the NTN may also be referred to by a term having the same or similar meaning.

[0140] In addition, the network entity supporting the above NTN may include a network entity capable of setting up an NTN cell that supports beam scheduling, and the following description will be based on a “network entity capable of setting up an NTN cell that supports beam scheduling.”

[0141] Referring to FIG. 7, this diagram illustrates a procedure for a terminal to obtain spot beam scheduling-related information. More specifically, the terminal can obtain information on the intentional activation and / or deactivation of a satellite cell through system information (or system information block (SIB)).

[0142] In step 710, the terminal (701) can receive system information from a network entity (703) supporting a non-terrestrial network (NTN).

[0143] The above system information may include SIBs (e.g., SIB19, SIB32) that must be received by the terminal to connect to NTN.

[0144] The above system information may include information related to spot beam scheduling. The above spot beam scheduling information may include information related to activation and deactivation times of NTN cells that support beam scheduling.

[0145] The structure including information related to activation and deactivation of NTN cells supporting beam scheduling in SIB may be as shown in [Table 1] below. The information related to activation and deactivation of NTN cells supporting beam scheduling may mean information including at least one of ntn-cellDutycycleStartSfn, ntn-cellActivationInfoList, ntn-CellActivationInfo, activationFinSfn inactivationDuration.

[0146]

[0147] System information according to an embodiment of the present disclosure may include the following information (or information element, IE). For reference, the following information may be transmitted as a system frame number (SFN) when the cell is activated, as the terminal and base station are in a synchronous situation, and may be transmitted as an absolute time radio frame number when the cell is deactivated, as the terminal and base station are in an asynchronous situation.

[0148] - ntn-cellDutycycleStartSfn: System Frame Number (SFN) at the start of the duty cycle for cell activation and deactivation.

[0149] - ntn-cellActivationInfoList: A list of a single continuous activation period and a group of a single continuous inactivity period based on the end point of the activation period, or a group list of ntn-CellActivationInfo.

[0150] - ntn-CellActivationInfo: A bundle of one continuous activation period and one continuous inactivation period based on the end of the activation period, which may contain avtivationFinSfn and inactivationDuration.

[0151] - activationFinSfn: System Frame Number (SFN) at the end of the activation period

[0152] - inactivationDuration: Radio Frame Number representing the duration of the inactivation period

[0153] According to an embodiment of the present disclosure, after receiving the above-described system information (or information related to the activation and deactivation times of NTN cells supporting beam scheduling), the terminal can calculate a pattern of repeated NTN cell activation and deactivation. Thereafter, the terminal can continuously use the system information for calculations until moving to another cell, and can perform operations according to an embodiment of the present disclosure even without additionally receiving information related to the activation and deactivation times of NTN cells supporting beam scheduling. In particular, the terminal can calculate and apply a pattern of repeated NTN cell activation and deactivation after initial access to a cell.

[0154] Hereinafter, a method for calculating the activation and deactivation cycle of an NTN cell based on information related to the activation and deactivation times of an NTN cell supporting beam scheduling in FIGS. 8a and 8b will be described.

[0155] FIG. 8A and FIG. 8B are diagrams illustrating a method for a terminal to calculate activation and deactivation patterns of a non-terrestrial network (NTN) cell for which beam scheduling is set according to an embodiment of the present disclosure.

[0156] Referring to FIG. 8a, this is a diagram for explaining information required for a terminal to calculate an activation and deactivation pattern of a non-terrestrial network (NTN) cell (or an activation and deactivation cycle of an NTN cell, or an activation and deactivation time of an NTN cell) due to beam scheduling settings.

[0157] - ntn-cellDutycycleStartSfn: Duty cycle start time information

[0158] - CellActivationInfo: A set of activationFinSfn and inactivationDuration

[0159] - activationFinSfn: Activation period end time information

[0160] - inactivationDuration: Inactivation period information

[0161] Referring to FIG. 8b, this is a diagram for explaining how a terminal calculates an activation and deactivation pattern of an NTN cell due to beam scheduling settings.

[0162] The information for calculating the activation and deactivation periods of NTN cells due to beam scheduling settings is as follows.

[0163]

[0164] For reference, the first activation period end time information (activationFinSfn) and the first inactivation period information (inactivationDuration) can be included in a single ntn-CellActivationInfo. Additionally, the second activation period end time information (activationFinSfn) and the second inactivation period information (inactivationDuration) can be included in a single ntn-CellActivationInfo. A list of such ntn-CellActivationInfo can be transmitted in the form of ntn-cellActivationInfoList.

[0165] The method for calculating the activation and inactivity periods of NTN cells may be as follows:

[0166]

[0167] Although Fig. 8b describes a method of calculating based on two activation and deactivation cycles of NTN cells, this is only one embodiment and the scope of the present invention is not limited thereto.

[0168] Below, we describe the operation method of RRC idle / inactive of a terminal when deactivated due to beam scheduling settings of an NTN cell.

[0169] FIG. 9 is a flowchart illustrating a method for a terminal to maintain a radio resource control (RRC) idle and inactive state when the terminal is inactive due to beam scheduling settings of a non-terrestrial network (NTN) cell according to an embodiment of the present disclosure.

[0170] Referring to FIG. 9, this is a flowchart of a method for maintaining a radio resource control (RRC) idle or inactive state of a terminal depending on whether it is activated or deactivated due to beam scheduling settings of a non-terrestrial network (NTN) cell.

[0171] In the following, whether an NTN cell is activated or deactivated is described on the assumption that it is activated or deactivated due to beam scheduling settings.

[0172] When spot beam scheduling (or spot beam hopping) is set, the inactivity of a specific NTN cell is not due to the cell's unintentional disappearance, but rather a temporary inactivity due to the satellite network's intention. Therefore, performing cell reselection in this case may be an unnecessary operation. In particular, cells in NTN are much larger than cells in terrestrial networks, with a diameter of approximately 20 to 100 km. In addition, since a terminal can often connect to only one NTN cell, cell reselection performed when a cell is inactivated is unnecessary when only one cell is connectable, and the increased power consumption due to the cell reselection procedure is also inefficient.

[0173] To address these issues, the present disclosure proposes a method for maintaining an RRC idle / inactive state when an NTN cell is in an inactive state due to beam scheduling settings. This is because the inactive state of an NTN cell is intentionally deactivated in a satellite network, and therefore, maintaining an RRC idle or inactive state is more advantageous in terms of power consumption of the terminal than having the terminal perform a cell reselection procedure.

[0174] The specific operations proposed in this disclosure are as follows.

[0175] At step 910, the terminal can camp on an NTN cell.

[0176] In step 920, the terminal can obtain information related to activation and deactivation times of NTN cells that support beam scheduling.

[0177] More specifically, the terminal can obtain information related to activation and deactivation times of an NTN cell supporting beam scheduling by receiving system information (e.g., SIB19, SIB32) from a network entity capable of configuring an NTN cell supporting beam scheduling. If the system information includes information related to activation and deactivation times of an NTN cell supporting beam scheduling, the terminal can determine that the currently connected NTN cell is subject to the activation and deactivation functions.

[0178] In step 930, the terminal can calculate the activation and deactivation periods of connectable NTN cells based on information related to activation and deactivation times of NTN cells that support beam scheduling.

[0179] More specifically, the terminal can obtain information related to the activation and deactivation of an NTN cell for which a connectable beam scheduling is set while waiting, and calculate the activation and deactivation periods. The calculation method can follow the method described above.

[0180] Thereafter, in step 940, if the terminal fails to receive a reference signal, it can determine whether the NTN cell, which was judged to be connectable and waiting, is in an inactive period due to beam scheduling settings. The reference signal may include a synchronization signal block (SSB) or a reference signal.

[0181] If the connected cell is not in an inactive period due to beam scheduling settings, the terminal can perform a cell reselection procedure for cell reselection in step 950.

[0182] If the connected cell is determined to be in an inactive period due to beam scheduling settings, the terminal may maintain an RRC idle or inactive state in step 960.

[0183] More specifically, the terminal may maintain an RRC idle or inactive state and may omit the process of receiving an SSB, a master information block (MIB), or a system information block (SIB). In addition, the terminal may also perform a discontinuous reception (DRX) operation.

[0184] In addition, the terminal can store and reuse the measurement information from the most recent past, from the time of cell signal reception failure. That is, even if the terminal cannot receive cell signals from the cell to which it was connected, the terminal can maintain an idle / inactive state equivalent to continuously receiving signals from the cell and perform most of the corresponding functions (e.g., neighbor cell measurement). However, in such cases, the terminal does not perform the PDCCH monitoring of paging occasions function, which will be described in detail below.

[0185] FIGS. 10A and 10B are diagrams illustrating an operation of a terminal maintaining a radio resource control (RRC) idle and inactive state when the terminal is inactive due to beam scheduling settings of a non-terrestrial network (NTN) cell according to an embodiment of the present disclosure.

[0186] FIG. 10a illustrates the operation of a terminal according to a conventional technique, and FIG. 10b illustrates the operation of a terminal according to a method of one embodiment of the present disclosure.

[0187] Referring to Fig. 10a, the terminal cannot know the activation / deactivation related information due to the spot beam scheduling of the NTN cell on which it is camping (or the activation and deactivation time related information of the NTN cell that supports beam scheduling). Therefore, if the NTN cell on which the terminal is connected and camping performs activation / deactivation at regular intervals, when the NTN cell enters the deactivation state, the terminal cannot receive the cell's SSB. Since the terminal cannot receive the SSB, it can determine that the cell is missing. In other words, the terminal determines that the cell is unintentionally unavailable for access and performs the cell reselection procedure from the moment it fails to receive the SSB. In addition, it performs additional procedures such as measuring the neighboring cells or neighboring radio access technology (RAT) signals. Since the terminal gives priority to searching (or finding) neighboring accessible cells, it performs the cell search procedure while actively using the terminal's power, which quickly consumes the available power of the terminal.

[0188] In summary, the terminal according to the prior art performs a cell reselection process accompanied by cell search even in an intentional NTN deactivation situation due to spot beam scheduling, thereby consuming a lot of power compared to the idle / inactive state.

[0189] Referring to FIG. 10b, a terminal according to an embodiment of the present disclosure may maintain an RRC idle / inactive state when it is determined that an NTN cell is inactive due to beam scheduling settings, and may not perform an unnecessary cell reselection procedure.

[0190] According to an embodiment of the present disclosure, when a terminal fails to acquire a reference signal, it can determine whether the corresponding cell is in an inactive period due to beam scheduling configuration. If it is determined that the corresponding cell is in an inactive period due to beam scheduling configuration, the terminal can apply the same mobility technique as the mobility of a terminal waiting in an existing cell without performing a cell reselection procedure. For example, the terminal can perform an idle mobility operation or a discontinuous reception (DRX) operation. This is because the cell (or NTN cell) is intentionally deactivated in the satellite network, so there is no need to perform an unnecessary cell reselection procedure. Through such an operation, the terminal can reduce unnecessary power consumption.

[0191] FIG. 11 is a flowchart illustrating a sequence for omitting physical downlink control channel (PDCCH) monitoring when a terminal is deactivated due to beam scheduling settings of a non-terrestrial network (NTN) cell according to an embodiment of the present disclosure.

[0192] According to one embodiment of the present disclosure, a method is proposed for omitting physical downlink control channel (PDCCH) monitoring depending on whether a non-terrestrial network (NTN) cell supporting beam scheduling is activated or deactivated.

[0193] In the following, whether an NTN cell is activated or deactivated is described on the assumption that it is activated or deactivated due to beam scheduling settings.

[0194] More specifically, during cell inactivity periods due to beam scheduling (or beam hopping), idle / inactive terminals cannot use the uplink and / or downlink. That is, when a cell is inactive, a waiting terminal does not receive a paging message from the cell on which it is currently waiting.

[0195] In existing terrestrial networks, idle / inactive terminals periodically monitor PDCCH paging occasions to receive paging messages to detect downlink traffic generation. However, during cell inactivity periods due to beam scheduling, paging message transmission and reception are impossible, making PDCCH paging occasion monitoring unnecessary and wasteful. To address this issue, the specific operations proposed in this disclosure are as follows.

[0196] In step 1110, the terminal can obtain information related to the activation and deactivation times of the NTN cell supporting beam scheduling. More specifically, the terminal can obtain information related to the activation and deactivation times of the NTN cell supporting beam scheduling by receiving system information (e.g., SIB19, SIB32) from a network entity capable of configuring the NTN cell supporting beam scheduling.

[0197] In step 1120, the terminal can determine whether the current serving cell is in a deactivated state due to beam scheduling settings based on information related to activation and deactivation times of the NTN cell supporting the beam scheduling.

[0198] At step 1130, if the serving cell is not in a disabled state with beam scheduling set, the terminal can perform a cell search procedure for cell reselection.

[0199] In step 1140, if the serving cell is in an inactive state due to beam scheduling configuration, the terminal may omit PDCCH monitoring in the on duration.

[0200] More specifically, the terminal can determine whether discontinuous reception (DRX) is operating when the serving cell is in a cell-inactive state due to spot beam scheduling. When the DRX of the terminal is operating, the terminal performs various functions during the on duration, but may enter a sleep state during the off duration. Thereafter, the terminal must perform PDCCH monitoring for paging during the on duration situation. In this case, the terminal can omit PDCCH monitoring for paging even during the DRX on duration during the inactive period of the serving cell.

[0201] Thereafter, at step 1150, the terminal can resume PDCCH monitoring when the serving cell switches to an active state.

[0202] FIG. 12 is a diagram illustrating a method for a terminal to omit monitoring of a physical downlink control channel (PDCCH) when the terminal is inactive due to beam scheduling settings of a non-terrestrial network (NTN) cell according to an embodiment of the present disclosure.

[0203] According to one embodiment of the present disclosure, a terminal in a radio resource control (RRC) idle / inactive state can perform a discontinuous reception (DRX) operation. The terminal performing the DRX operation can determine whether the current serving NTN cell is in a cell inactive state due to spot beam scheduling.

[0204] If the current serving cell is in a cell inactivity period due to beam scheduling, the terminal may omit monitoring the paging channel for physical downlink control channel (PDCCH) paging during the DRX on duration.

[0205] FIG. 13 is a flowchart illustrating a method for a terminal to delay transmission of uplink traffic when a non-terrestrial network (NTN) cell is inactive due to beam scheduling settings according to an embodiment of the present disclosure.

[0206] According to one embodiment of the present disclosure, a method is proposed for postponing a random access procedure for uplink traffic transmission depending on whether a beam scheduling configuration of an NTN cell supporting beam scheduling is activated or deactivated. More specifically, a method is proposed for not performing a random access procedure during an inactive period of a non-terrestrial network (NTN) cell due to beam scheduling.

[0207] In the following, whether an NTN cell is activated or deactivated is described on the assumption that it is activated or deactivated due to beam scheduling settings.

[0208] In existing terrestrial networks, when uplink traffic occurs at a terminal, the terminal immediately attempts to connect to a waiting cell to minimize uplink delay. To connect to a cell, the terminal performs a random access procedure (RACH procedure). If this procedure is successful, uplink and / or downlink communication can be performed.

[0209] However, according to the conventional technology, if the NTN cell is in an inactive state due to beam scheduling settings, even if the terminal transmits a signal for RA, the network entity supporting NTN cannot receive the signal transmitted by the terminal. Therefore, a continuous random access procedure failure occurs between the terminal and the base station during the inactive period of the NTN cell.

[0210] The present disclosure proposes a method for delaying a random access procedure for uplink traffic transmission to prevent persistent random access procedure failures. The specific operations proposed in the present disclosure are as follows.

[0211] In step 1310, the terminal can obtain information related to the activation and deactivation times of the NTN cell supporting beam scheduling. More specifically, the terminal can obtain information related to the activation and deactivation times of the NTN cell supporting beam scheduling by receiving system information from a network entity capable of configuring the NTN cell supporting beam scheduling.

[0212] In step 1320, the terminal can calculate the activation and deactivation periods of the waiting cell based on information related to the activation and deactivation times of the NTN cell that supports the beam scheduling. More specifically, the terminal can calculate the cell activation and deactivation periods of the currently waiting cell due to beam scheduling.

[0213] At step 1330, uplink traffic may occur at the terminal.

[0214] In step 1340, the terminal can determine whether the occurrence time of the uplink traffic is an inactive period due to beam scheduling settings of a waiting cell.

[0215] In step 1350, if the time of occurrence of uplink traffic is not an inactive period due to beam scheduling settings of a waiting cell, the terminal can immediately perform a random access procedure for transmitting the uplink traffic.

[0216] In step 1360, if the time of occurrence of uplink traffic is an inactive period due to beam scheduling settings of a waiting cell, the terminal can wait for a random access procedure until the waiting cell transitions to an active state.

[0217] More specifically, if uplink traffic is generated in a terminal in an RRC idle / inactive state and the time of generation of the uplink traffic is an inactive period due to beam scheduling of a waiting cell, the random access procedure is not performed at the time of generation of the uplink traffic. Thereafter, the terminal may change the random access procedure to be performed at the activation time of the waiting NTN cell in the nearest future from that time.

[0218] In step 1370, the terminal can perform a random access procedure when the waiting cell becomes active.

[0219] FIG. 14 is a diagram illustrating an operation of a terminal according to an embodiment of the present disclosure to delay transmission of uplink traffic when a non-terrestrial network (NTN) cell is inactive due to beam scheduling settings.

[0220] According to one embodiment of the present disclosure, a terminal can determine whether uplink traffic has occurred in a radio resource control (RRC) idle / inactive state. If uplink traffic has occurred, the terminal can determine whether an NTN cell is active.

[0221] If the above NTN cell is active, a random access procedure can be performed immediately.

[0222] On the other hand, if the current NTN cell is in an inactive state due to beam scheduling settings, the terminal can postpone the random access procedure until the cell transitions to an active state, and when the cell transitions to an active state, the terminal can perform the random access procedure for transmitting uplink traffic.

[0223] FIG. 15 is a flowchart illustrating a sequence for performing cell reselection when beam scheduling of a non-terrestrial network (NTN) cell is disabled due to a setting according to one embodiment of the present disclosure.

[0224] According to one embodiment of the present disclosure, a method for preventing ping-pong phenomenon in a situation where at least two non-terrestrial network (NTN) cells coexist depending on whether the cells are activated or deactivated is proposed.

[0225] According to the prior art, a terminal in an RRC idle / inactive state can change the waiting cell based on the signal information (e.g., signal strength) of two cells in a terrestrial network when the terminal is in an area where two cells are simultaneously accessible. The signal information may include reference signal received power (RSRP) and reference signal received quality (RSRQ). Thereafter, the terminal can perform a decision process for changing the current waiting cell by comparing the signal information of the current waiting cell with the signal information of neighboring cells.

[0226] The above procedure can also be performed during periods of cell inactivity due to beam scheduling. Due to beam scheduling, the currently standby cell and neighboring cells undergo a repeated activation / deactivation process. If neither the currently standby cell nor the neighboring cell are activated simultaneously, a state in which only one cell's signal can be received may occur repeatedly. Consequently, the terminal repeatedly reselects the standby cell as an activated cell. This is called the ping-pong phenomenon.

[0227] To solve these problems, the present disclosure proposes a method for selecting a cell based on signal information at the last reception of a signal of a standby NTN cell when the signal of the currently standby NTN cell is in a cell-inactive state due to beam scheduling settings and cannot be received, and a signal from a neighboring cell can be received. In the following description, whether the NTN cell is active or inactive is assumed to be an active or inactive state due to beam scheduling settings.

[0228] The specific operations proposed in this disclosure are as follows.

[0229] In step 1510, the terminal can obtain information related to the activation and deactivation times of the NTN cell supporting beam scheduling. More specifically, the terminal can obtain information related to the activation and deactivation times of the NTN cell supporting beam scheduling by receiving system information from a network entity capable of configuring the NTN cell supporting beam scheduling.

[0230] In step 1520, the terminal can calculate the activation and deactivation periods due to the beam scheduling settings of the first cell based on information related to the activation and deactivation times of the NTN cell supporting the beam scheduling.

[0231] More specifically, the first cell may include an NTN cell that supports currently waiting beam scheduling. The terminal may calculate the activation and deactivation periods of the first cell due to the beam scheduling settings.

[0232] At step 1530, the terminal may determine that the first cell is in an inactive state due to beam scheduling settings.

[0233] At step 1540, the terminal may transition to (or enter into) a radio resource control (RRC) idle / inactive state.

[0234] At step 1550, the terminal may discover a second cell that is active. The second cell may include a neighbor cell.

[0235] In step 1560, the terminal can perform a cell selection (or cell reselection) procedure based on the last received signal information of the first cell and the received signal information of the second cell.

[0236] More specifically, the first cell currently on standby is in a state where signal reception is not possible due to cell inactivity, and can receive a signal from the second cell, which is a neighboring cell. When the terminal receives a signal from the second cell during the inactivity period of the first cell, the terminal can select a cell by comparing the last received signal information of the first cell with the signal information of the second cell. At this time, the last received signal information of the first cell and the signal information of the second cell, which are to be compared, may include at least one of reference signals received power (RSRP), reference signal received quality (RSRQ), and received signal strength indication (RSSI), respectively.

[0237] FIGS. 16a and 16b are diagrams illustrating an operation of a terminal to suspend a random access procedure when beam scheduling of a non-terrestrial network (NTN) cell is disabled due to a setting according to an embodiment of the present disclosure.

[0238] FIG. 16a illustrates the operation of a terminal according to a conventional technique, and FIG. 16b illustrates the operation of a terminal according to a method of one embodiment of the present disclosure.

[0239] Referring to Figure 16a, in a situation where beam scheduling technology is applied in a non-terrestrial network (NTN), a terminal may be located in an area where two NTN cells can be accessed simultaneously. Depending on the activation / deactivation cycle of the NTN cells, one of the two NTN cells may be in an inactive state. In this case, the terminal cannot receive signals transmitted from the two NTN cells simultaneously, but receives them alternately.

[0240] More specifically, the terminal may be located in an area where both cell A and cell B are accessible, and the activation times of cell A and cell B may be scheduled differently. More specifically, when cell A becomes inactive, the terminal can no longer receive the synchronization signal block (SSB) that it was receiving from cell A. Since the terminal has not received the SSB from cell A, it performs cell reselection. After this, when cell B becomes active, cell B starts transmitting SSB, and the terminal receives the SSB of cell B. The terminal may consider that cell A has disappeared and cell B has appeared, and may perform necessary processes (e.g., Tracking Area Update, etc.) while changing the standby cell from cell A to cell B. Thereafter, when cell B becomes inactive, the terminal performs cell reselection and when cell A becomes active, it changes the standby cell to cell A. In other words, an idle / inactive terminal in an area where two or more cells are accessible generates a ping-pong effect in which all accessible cells are set as standby cells once per duty cycle.

[0241] Referring to FIG. 16b, the terminal may not immediately change the standby cell even if the signal of the current standby cell cannot be received due to cell inactivity.

[0242] More specifically, if the terminal cannot receive the signal of the current standby cell due to cell inactivity caused by beam scheduling settings and the signal of the neighbor cell is received during the inactivity period of the current standby cell, the terminal can compare the signal information at the time of the last reception of the standby cell signal with the newly received signal of the neighbor cell.

[0243] Therefore, when a standby cell (e.g., cell A) becomes inactive, it is possible to determine whether to change cells by comparing the last received signal of the standby cell signal with the signal of an activated neighboring cell (e.g., cell B).

[0244] However, although FIG. 16 has been described based on the case where two cells coexist for the purpose of explaining the present invention, the scope of the rights of the present invention is not limited thereto, and a case where two or more cells exist may also be included in the scope of the rights of the present invention.

[0245] FIG. 17 is a flowchart illustrating a sequence of terminal operations according to an embodiment of the present disclosure.

[0246] Whether an NTN cell is activated or deactivated is described on the assumption that it is activated or deactivated due to beam scheduling settings.

[0247] At step 1710, the terminal can receive system information (e.g., SIB19, SIB32) including information related to activation and deactivation times of a non-terrestrial network (NTN) cell that supports beam scheduling.

[0248] In step 1720, the terminal can determine activation and deactivation information due to beam scheduling settings of the first cell based on information related to activation and deactivation times of the NTN cell that supports the beam scheduling. The first cell may include a standby cell and may include a current serving cell. In addition, the activation and deactivation information of the first cell may include an activation and deactivation pattern (or cycle, or state) of the first activated cell.

[0249] In step 1730, the terminal can perform an operation according to the radio resource control (RRC) idle / inactive state of the terminal based on information related to the activation and deactivation times of the NTN cell that supports beam scheduling of the first cell.

[0250] Each step may be performed according to the embodiments described above. According to the present invention, each of the embodiments described above may be performed independently or may be performed in combination.

[0251] FIG. 18 is a flowchart illustrating a sequence of network entity operations supporting a non-terrestrial network (NTN) according to one embodiment of the present disclosure.

[0252] Whether an NTN cell is activated or deactivated is described on the assumption that it is activated or deactivated due to beam scheduling settings.

[0253] A network entity supporting a non-terrestrial network (NTN) may include both a satellite supporting NTN and a base station connected to a satellite supporting NTN. For example, in the case of a regenerative payload satellite in which the satellite functions as a base station, the network entity supporting NTN may refer to the regenerative payload satellite itself. If the satellite is a transparent payload satellite that functions as a relay, the network entity supporting NTN may refer to a base station existing on the ground. The network entity supporting NTN is not limited to the above-described embodiment, and depending on the configuration of the satellite network, the network entity supporting NTN may also be referred to by a term having the same or similar meaning.

[0254] Additionally, the network entity supporting the above NTN may include a network entity capable of setting up an NTN cell that supports beam scheduling.

[0255] At step 1810, a network entity capable of configuring an NTN cell that supports beam scheduling can generate a system information block that includes information related to activation and deactivation times of the NTN cell that supports beam scheduling.

[0256] In step 1820, a network entity capable of setting an NTN cell that supports the beam scheduling can transmit system information including information related to activation and deactivation times of the NTN cell that supports the beam scheduling to the terminal.

[0257] FIG. 19 is a diagram illustrating the internal structure of a terminal according to an embodiment of the present disclosure.

[0258] For convenience of explanation, the description will focus on terminals, but the scope of the present invention is not limited thereto. The scope of the present invention may include all devices supporting non-terrestrial networks (NTNs).

[0259] A device (or "entity") supporting a non-terrestrial network (NTN) according to an embodiment of the present disclosure may include a user-portable terminal (e.g., a user equipment (UE) such as a smartphone), a very small aperture terminal (VSAT) equipped with a parabolic antenna or phase array antenna, or a low-power device (e.g., an Internet of Things device or a sensor). For convenience of explanation, the following description will focus on terminals, but the scope of the present invention is not limited thereto.

[0260] Referring to FIG. 19, a terminal (1910) according to one embodiment of the present disclosure may include a transceiver (1920), a control unit (1930), and a storage unit (1940).

[0261] The transceiver (1920) can transmit and receive signals. The transceiver (1920) can transmit signals to a satellite or a base station according to an embodiment of the present disclosure, and receive signals from the satellite or the base station, for example.

[0262] In the present disclosure, the control unit (1930) of the terminal may be defined as a circuit, an application-specific integrated circuit, or at least one processor. The control unit (1930) may control the overall operation of the terminal according to an embodiment proposed in the present disclosure. For example, the control unit (1930) may control the signal flow between each block to perform operations according to the drawings (or, flowcharts, flow charts) described above.

[0263] The storage unit (1940) can store at least one of information transmitted and received through the transmission and reception unit (1920) and information generated through the control unit (1930).

[0264] FIG. 20 is a diagram illustrating the internal structure of a network entity supporting NTN according to one embodiment of the present disclosure.

[0265] A network entity supporting a non-terrestrial network (NTN) may include both a satellite supporting NTN and a base station connected to a satellite supporting NTN. For example, in the case of a regenerative payload satellite in which the satellite functions as a base station, the network entity supporting NTN may refer to the regenerative payload satellite itself. If the satellite is a transparent payload satellite that functions as a relay, the network entity supporting NTN may refer to a base station existing on the ground. The network entity supporting NTN is not limited to the above-described embodiment, and depending on the configuration of the satellite network, the network entity supporting NTN may also be referred to by a term having the same or similar meaning.

[0266] Referring to FIG. 20, a network entity supporting NTN according to one embodiment of the present disclosure (2010) may include a transceiver (2020), a control unit (2030), and a storage unit (2040).

[0267] A network entity supporting NTN may include a network entity capable of configuring NTN cells that support beam scheduling.

[0268] The transceiver (2020) can transmit and receive signals. The transceiver (2020) can transmit signals to a satellite or a base station according to an embodiment of the present disclosure, and receive signals from the satellite or the base station, for example.

[0269] In the present disclosure, the control unit (2030) of the terminal may be defined as a circuit, an application-specific integrated circuit, or at least one processor. The control unit (2030) may control the overall operation of the terminal according to an embodiment proposed in the present disclosure. For example, the control unit (2030) may control the signal flow between each block to perform operations according to the drawings (or, flowcharts, flow charts) described above.

[0270] The storage unit (2040) can store at least one of information transmitted and received through the transmission and reception unit (2020) and information generated through the control unit (2030).

[0271] The methods according to the embodiments described in the claims or specification of the present invention may be implemented in the form of hardware, software, or a combination of hardware and software.

[0272] When implemented in software, a computer-readable storage medium storing one or more programs (software modules) may be provided. The one or more programs stored in the computer-readable storage medium are configured for execution by one or more processors within an electronic device. The one or more programs include instructions that cause the electronic device to execute methods according to the embodiments described in the claims or specification of the present invention.

[0273] These programs (software modules, software) may be stored in random access memory, non-volatile memory including flash memory, read only memory (ROM), electrically erasable programmable read only memory (EEPROM), magnetic disc storage device, compact disc ROM (CD-ROM), digital versatile discs (DVDs) or other forms of optical storage device, magnetic cassette. Or, they may be stored in a memory configured as a combination of some or all of these. In addition, each configuration memory may be included in multiple numbers.

[0274] Additionally, the program may be stored in an attachable storage device that is accessible via a communication network such as the Internet, an intranet, a local area network (LAN), a wide local area network (WLAN), a storage area network (SAN), or a combination thereof. Such a storage device may be connected to a device implementing an embodiment of the present invention via an external port. Additionally, a separate storage device on the communication network may be connected to a device implementing an embodiment of the present invention.

[0275] In the specific embodiments of the present invention described above, components included in the invention are expressed in the singular or plural form depending on the specific embodiment presented. However, the singular or plural expressions are selected to suit the presented situation for convenience of explanation, and the present invention is not limited to singular or plural components. Even components expressed in the plural form may be composed of singular elements, or even components expressed in the singular form may be composed of plural elements.

[0276] While the detailed description of the present invention has described specific embodiments, it is clear that various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined not only by the scope of the following claims but also by equivalents thereof.

Claims

1. A method performed by a terminal supporting a non-terrestrial network (NTN), A step of receiving a system information block (SIB) including activation and deactivation related time information of an NTN cell supporting beam scheduling from a network entity capable of configuring an NTN cell supporting beam scheduling; A step of determining activation and deactivation period information of a first NTN cell based on activation and deactivation related time information of an NTN cell supporting the above beam scheduling; and A method characterized by performing a radio resource control (RRC) idle state or inactive operation based on activation and inactivation period information of a first NTN cell.

2. In paragraph 1, The above system information block includes either system information block 19 (SIB 19) or SIB 32, The above system information block includes at least one of information on the start time of the activation and deactivation cycle of the first NTN cell, information on the end time of the first activation cycle of the first NTN cell, or information on the duration of the first deactivation cycle of the first NTN cell. A method characterized in that whether the first NTN cell is activated is determined by beam scheduling of a network entity supporting the NTN.

3. In the first paragraph, the RRC idle or inactive operation A step of determining whether the first NTN cell is in an inactive state when a reference signal is not received from the first NTN cell; A step of maintaining the RRC idle or inactive state of the terminal when the first NTN cell is in an inactive state; and characterized in that when the above first NTN cell is in an activated state, a cell search procedure is performed; A method characterized in that the first NTN cell comprises a camping cell.

4. In paragraph 1, the RRC idle or inactive operation is A step of determining whether the terminal supports discontinuous reception (DRX); A step of omitting monitoring of a physical downlink control channel (PDCCH) during the DRX on duration period of the terminal when the first NTN cell is in an inactive state; and Including a step of monitoring PDCCH during the DRX on duration period of the terminal when the first NTN cell is activated, A method characterized in that the first NTN cell comprises a serving cell.

5. In paragraph 1, the RRC idle or inactive operation is The step where uplink traffic occurs; A step of determining whether the time point at which the above uplink traffic occurs is an inactive period of the first NTN cell; When the time of occurrence of the above uplink traffic is during the inactive period of the first NTN cell, a step of suspending the random access procedure until the start time of the active period of the first NTN cell; and When the above uplink traffic occurrence time is the activation period of the first NTN cell, a step of performing a random access procedure is included. A method characterized in that the first NTN cell comprises a camping cell.

6. In paragraph 1, the RRC idle or inactive operation is A step of determining whether the first NTN cell is in an inactive state; A step of receiving a signal of a second NTN cell that is activated when the first NTN cell is in an inactive state; It is characterized by including a step of determining whether to perform cell reselection to the second NTN cell based on information of the last received signal before the first NTN cell becomes inactive and information of the received signal of the second NTN cell. A method characterized in that the first NTN cell comprises a camping cell and the second NTN cell comprises at least one neighboring cell.

7. A method performed by a network entity supporting a non-terrestrial network (NTN), A step of generating a system information block including information related to activation and deactivation times of NTN cells supporting beam scheduling; and A step of transmitting a system information block including information related to activation and deactivation times of NTN cells supporting the above beam scheduling, The activation and deactivation period information of the first NTN cell is based on the activation and deactivation time related information of the NTN cell supporting the beam scheduling. A method characterized in that radio resource control (RRC) idle or inactive operation is based on activation and inactive period information of a first NTN cell.

8. In paragraph 7, The above system information includes either system information block 19 (SIB 19) or SIB 32, The above system information includes at least one of information on the start time of the activation and deactivation cycle of the first NTN cell, information on the end time of the first activation cycle of the first NTN cell, or information on the duration of the first deactivation cycle of the first NTN cell. A method characterized in that whether the first NTN cell is activated is determined by beam scheduling of a network entity supporting the NTN.

9. For terminals supporting non-terrestrial networks (NTN), A transceiver for transmitting and receiving signals; and A control unit is included, wherein the control unit comprises: Receive a system information block (SIB) including activation and deactivation time information of an NTN cell supporting beam scheduling from a network entity capable of configuring an NTN cell supporting beam scheduling, Based on the activation and deactivation related time information of the NTN cell supporting the above beam scheduling, the activation and deactivation period information of the first NTN cell is determined, A terminal characterized by performing a radio resource control (RRC) idle state or inactive operation based on activation and deactivation period information of a first NTN cell.

10. In paragraph 9, the control unit, If the reference signal is not received from the first NTN cell, determine whether the first NTN cell is in an inactive state, If the above first NTN cell is inactive, the terminal maintains the RRC idle or inactive state, If the above first NTN cell is active, a cell search procedure is performed, The above first NTN cell includes a camping cell, The above system information block includes either system information block 19 (SIB 19) or SIB 32, The above system information block includes at least one of information on the start time of the activation and deactivation cycle of the first NTN cell, information on the end time of the first activation cycle of the first NTN cell, or information on the duration of the first deactivation cycle of the first NTN cell. A terminal characterized in that whether the first NTN cell is activated is determined by beam scheduling of a network entity supporting the NTN.

11. In paragraph 9, the control unit, Determine whether the above terminal supports discontinuous reception (DRX), When the first NTN cell is in an inactive state, monitoring of the physical downlink control channel (PDCCH) is omitted during the DRX on duration period of the terminal. When the above first NTN cell is activated, the PDCCH is monitored during the DRX on duration period of the terminal, A terminal, characterized in that the first NTN cell includes a serving cell.

12. In paragraph 9, the control unit, Uplink traffic occurs, It is determined whether the above uplink traffic occurrence time is within the inactive period of the first NTN cell, If the above uplink traffic occurrence time is during the inactive period of the first NTN cell, the random access procedure is suspended until the start of the active period of the first NTN cell. If the above uplink traffic occurrence time is during the activation period of the first NTN cell, a random access procedure is performed, A terminal characterized in that the first NTN cell includes a camping cell.

13. In paragraph 9, the control unit, Determine whether the above first NTN cell is inactive, When the first NTN cell is in an inactive state, a signal from the second NTN cell in an active state is received, Based on the information of the last received signal before the first NTN cell becomes inactive and the received signal information of the second NTN cell, it is determined whether to perform cell reselection to the second NTN cell, A terminal characterized in that the first NTN cell includes a camping cell and the second NTN cell includes at least one neighboring cell.

14. For network entities supporting non-terrestrial networks (NTNs), A transceiver for transmitting and receiving signals; and A control unit is included, wherein the control unit comprises: Generate a system information block containing information related to activation and deactivation times of NTN cells supporting beam scheduling, Transmits a system information block containing information related to activation and deactivation times of NTN cells supporting the above beam scheduling, The activation and deactivation period information of the first NTN cell is based on the activation and deactivation time related information of the NTN cell supporting the beam scheduling. A network entity characterized in that radio resource control (RRC) idle state or inactive operation is based on activation and inactive period information of the first NTN cell.

15. In paragraph 14, The above system information includes either system information block 19 (SIB 19) or SIB 32, The above system information includes at least one of information on the start time of the activation and deactivation cycle of the first NTN cell, information on the end time of the first activation cycle of the first NTN cell, or information on the duration of the first deactivation cycle of the first NTN cell. A network entity, characterized in that whether the first NTN cell is activated is determined by beam scheduling of a network entity supporting the NTN.

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