Method and apparatus for performing random access procedure in non-terrestrial network

Abstract

The present invention relates to a technique for performing a random access procedure in a non-terrestrial network. A method of a user equipment (UE) may be provided, the method comprising the steps of: receiving configuration information related to a random access channel from a satellite, the configuration information including polarized wave information to be used for transmitting a preamble; determining a polarized wave to be used based on the polarized wave information; selecting a preamble to be transmitted using the determined polarized wave; and transmitting the selected preamble to the satellite using the determined polarized wave.

Description

Technical Field

[0001] The present invention relates to a technology for performing a random access procedure in a non-terrestrial network, and more particularly, to a technology for transmitting a random access channel using polarization in the non-terrestrial network. Background Art

[0002] Communication networks (e.g., 5G communication networks, 6G communication networks, etc.) are being developed to provide enhanced communication services compared to existing communication networks (e.g., long term evolution (LTE), LTE-Advanced (LTE-A), etc.). 5G communication networks (e.g., New Radio (NR) communication networks) can support not only frequency bands of 6 GHz or below, but also frequency bands of 6 GHz or above. That is, the 5G communication network can support the frequency range FR1 band and / or FR2 band. Compared with the LTE communication network, the 5G communication network can support a wide variety of communication services and scenarios. For example, the usage scenarios of the 5G communication network may include enhanced Mobile BroadBand (eMBB), Ultra Reliable Low Latency Communication (URLLC), massive Machine Type Communication (mMTC), etc.

[0003] Compared with 5G communication networks, 6G communication networks can support a wide variety of communication services and scenarios. 6G communication networks can meet the requirements of ultra-performance, ultra-bandwidth, ultra-space, ultra-precision, ultra-intelligence and / or ultra-reliability. 6G communication networks can support various broadbands and can be applied to various usage scenarios (e.g., terrestrial communication, non-terrestrial communication, sidelink communication, etc.).

[0004] A communication network (e.g., a 5G communication network, a 6G communication network, etc.) can provide communication services to terminals located on the ground. Recently, the demand for communication services not only for the ground but also for non-ground aircraft, drones, and satellites has been increasing, and for this purpose, the technology of non-terrestrial networks (NTN) has been discussed. The non-terrestrial network can be implemented based on 5G communication technology, 6G communication technology, etc. For example, in a non-terrestrial network, communication between a satellite and a ground communication node or a non-terrestrial communication node (e.g., an aircraft, a drone, etc.) can be performed based on 5G communication technology, 6G communication technology, etc. In NTN, a satellite can perform the function of a base station in a communication network (e.g., a 5G communication network, a 6G communication network, etc.).

[0005] On the other hand, in non-terrestrial networks, the link quality may be degraded due to the long distance between the satellite and the terminal and the significant Doppler shift caused by high-speed movement. To overcome this, it may be necessary to improve the reception performance of the random access channel (RACH) during the initial access process of the uplink. Summary of the invention

[0006] Technical issues

[0007] The present invention is directed to providing a method and apparatus for performing a random access procedure in a non-terrestrial network by using a polarization transmission random access channel.

[0008] Technical Solution

[0009] A method for a user equipment (UE) for performing a random access procedure in a non-terrestrial network according to a first exemplary embodiment of the present invention for achieving the above-mentioned purpose may include: receiving configuration information related to a random access channel from a satellite, the configuration information including polarization information indicating a polarization to be used for sending a preamble; determining a polarization to be used based on the polarization information; selecting a preamble sequence to be sent using the determined polarization; and sending the selected preamble sequence to the satellite using the determined polarization.

[0010] The polarization information may include information about a polarization type to be used for sending a preamble code, and the polarization type may be at least one of left-hand circular polarization, right-hand circular polarization, or linear polarization, and determining the polarization to be used based on the polarization information may include: determining the polarization to be used among left-hand circular polarization, right-hand circular polarization, or linear polarization.

[0011] The polarization information may include information about the polarization type and information about a preamble code sequence that can be used for each polarization type, and when determining the polarization to be used based on the polarization information, the UE may determine the polarization type to be used, and selecting the preamble code sequence may include: selecting the preamble code sequence to be sent from the preamble code sequences that can be used for the determined polarization type.

[0012] The polarization information may include polarization pattern information, determining the polarization to be used based on the polarization information may include: determining an order of polarization types for repeatedly sending preamble codes based on the polarization pattern information, and sending the selected preamble code sequence to the satellite using the determined polarization may include: repeatedly sending the selected preamble code sequence to the satellite based on the determined order of polarization types.

[0013] Here, the polarization mode information may represent at least one of RRRL, RRLR, RLRR or LRRR, wherein R may represent right-hand circular polarization and L may represent left-hand circular polarization.

[0014] Here, the polarization mode information may represent at least one of VVVH, VVHV, VHVV or HVVV, wherein V may represent vertical polarization and H may represent horizontal polarization.

[0015] The method may further include receiving downlink control information (DCI) scrambled with a random access radio network temporary identifier (RA-RNTI) based on polarization information from a satellite; generating the RA-RNTI based on the polarization information; and decoding the DCI using the RA-RNTI.

[0016] A method for a satellite for performing a random access procedure in a non-terrestrial network according to a second exemplary embodiment of the present invention for achieving the above-mentioned purpose may include: sending configuration information related to a random access channel to a user equipment (UE), the configuration information including polarization information indicating a polarization to be used for sending a preamble; receiving a preamble sent using polarization based on the polarization information from the UE; and sending a response signal to the UE for the received preamble.

[0017] The polarization information may include information on a polarization type to be used for sending the preamble, and the polarization type may be at least one of left-hand circular polarization, right-hand circular polarization, or linear polarization.

[0018] The polarization information may include polarization pattern information, and receiving the preamble code transmitted from the UE using polarization based on the polarization information may include: repeatedly receiving the preamble code repeatedly transmitted based on the polarization pattern information from the UE.

[0019] The method may further include identifying the UE based on the polarization pattern information.

[0020] The method may further include generating an RA-RNTI based on the polarization information, and sending a response signal to the UE for the received preamble may include sending a DCI scrambled with the RA-RNTI; and sending the response signal to the UE according to the DCI.

[0021] A user equipment (UE) for performing a random access procedure in a non-terrestrial network according to a third exemplary embodiment of the present invention for achieving the above-mentioned purpose may include: at least one processor, which may enable the UE to execute: receiving configuration information related to a random access channel from a satellite, the configuration information including polarization information indicating a polarization to be used for sending a preamble; determining a polarization to be used based on the polarization information; selecting a preamble sequence to be sent using the determined polarization; and sending the selected preamble sequence to the satellite using the determined polarization.

[0022] The polarization information may include information about the polarization type to be used for sending the preamble code, and the polarization type may be at least one of left-hand circular polarization, right-hand circular polarization, or linear polarization, and when determining the polarization to be used based on the polarization information, the at least one processor may further cause the UE to execute: determine the polarization to be used among left-hand circular polarization, right-hand circular polarization, or linear polarization.

[0023] The polarization information may include polarization pattern information; when determining the polarization to be used based on the polarization information, the at least one processor may further cause the UE to execute: determining an order of polarization types for repeatedly sending the preamble code based on the polarization pattern information; when sending the selected preamble code sequence to the satellite using the determined polarization, the at least one processor may further cause the UE to execute: repeatedly sending the selected preamble code sequence to the satellite based on the determined order of polarization types.

[0024] The at least one processor may further cause the UE to perform: receiving downlink control information (DCI) scrambled with a random access radio network temporary identifier (RA-RNTI) based on polarization information from a satellite; generating the RA-RNTI based on the polarization information; and decoding the DCI using the RA-RNTI.

[0025] Beneficial effects

[0026] According to the present invention, the non-terrestrial network can increase the number of preamble combinations by additionally applying polarization. In addition, according to the present invention, the non-terrestrial network can reduce the probability of contention that occurs when multiple terminals select the same preamble sequence. In addition, according to the present invention, the non-terrestrial network can increase the number of random access channel combinations by utilizing polarization in repeated transmissions of the random access channel. In addition, according to the present invention, the non-terrestrial network can expect to improve reception performance through diversity. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1a is a conceptual diagram illustrating a first exemplary embodiment of a non-terrestrial network.

[0028] Figure 1bis a conceptual diagram illustrating a second exemplary embodiment of a non-terrestrial network.

[0029] Figure 2a is a conceptual diagram illustrating a third exemplary embodiment of a non-terrestrial network.

[0030] Figure 2b is a conceptual diagram illustrating a fourth exemplary embodiment of a non-terrestrial network.

[0031] Figure 2c is a conceptual diagram illustrating a fifth exemplary embodiment of a non-terrestrial network.

[0032] Figure 3 is a block diagram illustrating a first exemplary embodiment of communication nodes constituting a non-terrestrial network.

[0033] Figure 4 is a block diagram illustrating a first exemplary embodiment of a communication node performing communications.

[0034] Figure 5a is a block diagram illustrating a first exemplary implementation of a transmit path.

[0035] Figure 5b is a block diagram illustrating a first exemplary implementation of a receive path.

[0036] Figure 6a is a conceptual diagram illustrating a first exemplary embodiment of a protocol stack of a user plane in a non-terrestrial network based on a transparent payload.

[0037] Figure 6b is a conceptual diagram illustrating a first exemplary embodiment of a protocol stack of a control plane in a non-terrestrial network based on a transparent payload.

[0038] Figure 7a is a conceptual diagram illustrating a first exemplary embodiment of a protocol stack for a user plane in a non-terrestrial network based on a regenerative payload.

[0039] Figure 7b is a conceptual diagram illustrating a first exemplary embodiment of a protocol stack for a control plane in a non-terrestrial network based on a regenerative payload.

[0040] Figure 8 is a sequence diagram illustrating a first exemplary embodiment of a method of performing a random access procedure in a non-terrestrial network.

[0041] Fig. 9 is a sequence diagram illustrating a second exemplary embodiment of a method of performing a random access procedure in a non-terrestrial network.

[0042] Fig.10 It is shown that the use Figure 8 and Fig. 9A conceptual diagram of a first exemplary embodiment of a process for sending a preamble code in a polarization mode in FIG. DETAILED DESCRIPTION

[0043] Although the present invention is capable of various modifications and alternative forms, specific embodiments thereof are shown by way of example in the accompanying drawings and will be described in detail herein. However, it should be understood that it is not intended to limit the present invention to the specific forms disclosed, but on the contrary, the present invention covers all modifications, equivalents and alternative forms that fall within the spirit and scope of the present invention. Throughout the description of the drawings, the same reference numerals refer to the same elements.

[0044] It will be understood that, although the terms first, second, etc. can be used herein to describe each element, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, without departing from the scope of the present invention, the first element can be referred to as the second element and similarly, the second element can be referred to as the first element. As used in this article, the term "and / or" includes any combination and all combinations of one or more related enumeration items.

[0045] In the present invention, “at least one of A and B” may mean “at least one of A or B” or “at least one of a combination of one or more of A and B”. Furthermore, in an exemplary embodiment of the present invention, “one or more of A and B” may mean “one or more of A or B” or “one or more of a combination of one or more of A and B”.

[0046] In the present invention, "(re)transmission" may mean "transmission", "retransmission" or "transmission and retransmission", "(re)configuration" may mean "configuration", "reconfiguration" or "configuration and reconfiguration", "(re)connection" may mean "connection", "reconnection" or "connection and reconnection", and "(re)access" may mean "access", "reaccess" or "access and reaccess".

[0047] It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element, or there can be intervening elements. Conversely, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements.

[0048] The terms used in this article are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in this article, the singular form is intended to also include the plural form, unless the context clearly indicates otherwise. It will be further understood that when the terms "include" and / or "comprising" are used in this article, it is explained that there are described features, numerical values, steps, operations, elements, components or combinations thereof, but does not exclude the presence or addition of one or more other features, numerical values, steps, operations, elements, components and / or combinations thereof.

[0049] Unless otherwise defined, all terms (including technical and scientific terms) used in this article have the same meaning as those commonly understood by ordinary technicians in the field to which the present invention belongs. It will be further understood that terms (for example, terms defined in commonly used dictionaries) should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and will not be interpreted as an idealized or overly formal meaning unless explicitly defined as such in this article.

[0050] Hereinafter, the exemplary embodiments of the present invention will be described in more detail with reference to the accompanying drawings. In order to promote overall understanding when describing the present invention, the same components in the accompanying drawings are represented by the same reference numerals, and repeated descriptions thereof will be omitted. In addition to the exemplary embodiments clearly described in the present invention, operations can also be performed according to the combination of the exemplary embodiments, the expansion of the exemplary embodiments and / or the modification of the exemplary embodiments. The execution of some operations can be omitted, and the execution order of the operations can be changed.

[0051] Even when describing a method performed at a first communication node among communication nodes (e.g., transmission or reception of a signal), the corresponding second communication node may perform a method corresponding to the method performed at the first communication node (e.g., reception or transmission of a signal). That is, when describing the operation of a user equipment (UE), a base station corresponding to the UE may perform an operation corresponding to the operation of the UE. Conversely, when describing the operation of a base station, a UE corresponding to the base station may perform an operation corresponding to the operation of the base station. In a non-terrestrial network (NTN) (e.g., a payload-based NTN), the operation of a base station may refer to the operation of a satellite, and the operation of a satellite may refer to the operation of a base station.

[0052] A base station may refer to a node B, an evolved node B (eNodeB), a next generation node B (gNodeB), a gNB, a device, an apparatus, a node, a communication node, a base transceiver station (BTS), a radio remote head (RRH), a transmission reception point (TRP), a radio unit (RU), a roadside unit (RSU), a radio transceiver, an access point, an access node, etc. A UE may refer to a terminal, a device, an apparatus, a node, a communication node, an end node, an access terminal, a mobile terminal, a station, a subscriber station, a mobile station, a portable subscriber station, an on-board unit (OBU), etc.

[0053] In the present invention, signaling may be at least one of higher layer signaling, medium access control (MAC) signaling, or physical (PHY) signaling. A message for higher layer signaling may be referred to as a "higher layer message" or a "higher layer signaling message". A message for MAC signaling may be referred to as a "MAC message" or a "MAC signaling message". A message for PHY signaling may be referred to as a "PHY message" or a "PHY signaling message". Higher layer signaling may refer to the sending and receiving operations of system information (e.g., master information block (MIB), system information block (SIB)) and / or RRC messages. MAC signaling may refer to the sending and receiving operations of a MAC control element (CE). PHY signaling may refer to the sending and receiving operations of control information (e.g., downlink control information (DCI), uplink control information (UCI), and sidelink control information (SCI)).

[0054] In the present invention, “configure an operation (e.g., send an operation)” may mean “send configuration information (e.g., information element or parameter) of an operation and / or information indicating the execution of an operation with a signal”. “Configure an information element (e.g., parameter)” may mean “send a corresponding information element with a signal”. In the present invention, “signal and / or channel” may mean signal, channel, or “signal and channel”, and “signal” may be used to mean “signal and / or channel”.

[0055] The communication system may include at least one of a terrestrial network, a non-terrestrial network, a 4G communication network (e.g., a long term evolution (LTE) communication network), a 5G communication network (e.g., a new radio (NR) communication network), or a 6G communication network. Each of the 4G communication network, the 5G communication network, and the 6G communication network may include a terrestrial network and / or a non-terrestrial network. The non-terrestrial network may operate based on at least one communication technology of the LTE communication technology, the 5G communication technology, or the 6G communication technology. The non-terrestrial network may provide communication services in various frequency bands.

[0056] The communication network to which the exemplary embodiment is applied is not limited to the content described below, and the exemplary embodiment can be applied to various communication networks (e.g., 4G communication network, 5G communication network and / or 6G communication network). Here, the communication network can be used in the same sense as the communication system.

[0057] Figure 1a is a conceptual diagram illustrating a first exemplary embodiment of a non-terrestrial network.

[0058] like Figure 1a As shown, the non-terrestrial network (NTN) may include a satellite 110, a communication node 120, a gateway 130, a data network 140, etc. A unit including the satellite 110 and the gateway 130 may correspond to a remote radio unit (RRU). Figure 1a The NTN shown may be a transparent payload-based NTN. Satellite 110 may be a low earth orbit (LEO) satellite, a medium earth orbit (MEO) satellite, a geostationary earth orbit (GEO) satellite, a high elliptical orbit (HEO) satellite, or an unmanned aircraft system (UAS) platform. The UAS platform may include a high altitude platform station (HAPS). The non-GEO satellite may be a LEO satellite and / or a MEO satellite.

[0059] The communication node 120 may include a communication node located at a ground location (e.g., a user equipment (UE) or a terminal) and a communication node located in a non-ground space (e.g., an aircraft, a drone). A service link may be established between the satellite 110 and the communication node 120, and the service link may be a radio link. The satellite 110 may be referred to as an NTN payload. The gateway 130 may support multiple NTN payloads. The satellite 110 may provide communication services to the communication node 120 using one or more beams. The shape of the coverage area of ​​the beam of the satellite 110 may be elliptical or circular.

[0060] In non-terrestrial networks, the following three types of service links can be supported.

[0061] - Earth-fixed: The service link may be provided by a beam that always continuously covers the same geographical area (eg, a geosynchronous orbit (GSO) satellite).

[0062] - quasi-earth-fixed: the service link may be provided by a beam covering one geographical area during a defined period and by a beam covering another geographical area during another period (e.g. a non-GSO (NGSO) satellite forming a steerable beam).

[0063] - Earth-moving: The service link may be provided by a beam moving over the surface of the Earth (eg, a NGSO satellite forming a fixed or non-steerable beam).

[0064] The communication node 120 may perform communication (e.g., downlink communication and uplink communication) with the satellite 110 using 4G communication technology, 5G communication technology, and / or 6G communication technology. Communication between the satellite 110 and the communication node 120 may be performed using an NR-Uu interface and / or a 6G-Uu interface. When supporting dual connectivity (DC), the communication node 120 may be connected to other base stations (e.g., base stations supporting 4G, 5G, and / or 6G functions) and the satellite 110, and perform DC operations based on technologies defined in 4G, 5G, and / or 6G technical specifications.

[0065] The gateway 130 may be located at a ground location, and a feeder link may be established between the satellite 110 and the gateway 130. The feeder link may be a radio link. The gateway 130 may be referred to as a "non-terrestrial network (NTN) gateway". The communication between the satellite 110 and the gateway 130 may be performed based on an NR-Uu interface, a 6G-Uu interface, or a satellite radio interface (SRI). The gateway 130 may be connected to the data network 140. There may be a "core network" between the gateway 130 and the data network 140. In this case, the gateway 130 may be connected to the core network, and the core network may be connected to the data network 140. The core network may support 4G communication technology, 5G communication technology, and / or 6G communication technology. For example, the core network may include an access and mobility management function (AMF), a user plane function (UPF), a session management function (SMF), and the like. Communication between the gateway 130 and the core network may be performed based on an NG-C / U interface or a 6G-C / U interface.

[0066] like Figure 1b As shown in the exemplary embodiment of FIG. 1 , in a transparent payload-based NTN, a “core network” may exist between the gateway 130 and the data network 140 .

[0067] Figure 1b is a conceptual diagram illustrating a second exemplary embodiment of a non-terrestrial network.

[0068] like Figure 1b As shown, the gateway can be connected to the base station, the base station can be connected to the core network, and the core network can be connected to the data network. Each of the base station and the core network can support 4G communication technology, 5G communication technology and / or 6G communication technology. The communication between the gateway and the base station can be performed based on the NR-Uu interface or the 6G-Uu interface, and the communication between the base station and the core network (e.g., AMF, UPF, SMF, etc.) can be performed based on the NG-C / U interface or the 6G-C / U interface.

[0069] Figure 2a is a conceptual diagram illustrating a third exemplary embodiment of a non-terrestrial network.

[0070] like Figure 2a As shown, the non-terrestrial network may include a first satellite 211, a second satellite 212, a communication node 220, a gateway 230, a data network 240, and the like. Figure 2aThe NTN shown may be an NTN based on a regenerated payload. For example, each of satellite 211 and satellite 212 may perform a regeneration operation (e.g., demodulation, decoding, re-encoding, re-modulation, and / or filtering operation) on a payload received from another entity (e.g., communication node 220 or gateway 230) and transmit the regenerated payload.

[0071] Each of satellite 211 and satellite 212 can be a LEO satellite, a MEO satellite, a GEO satellite, a HEO satellite or a UAS platform. The UAS platform can include a HAPS. Satellite 211 can be connected to satellite 212, and an inter-satellite link (ISL) can be established between satellite 211 and satellite 212. ISL can operate in an RF band or an optical band. ISL can be optionally established. Communication node 220 can include a ground communication node (e.g., UE or terminal) and a non-ground communication node (e.g., an aircraft or a drone). A service link (e.g., a radio link) can be established between satellite 211 and communication node 220. Satellite 211 can provide communication services to communication node 220 using one or more beams.

[0072] The communication node 220 can perform communication (e.g., downlink communication or uplink communication) with the satellite 211 using 4G communication technology, 5G communication technology, and / or 6G communication technology. The communication between the satellite 211 and the communication node 220 can be performed using the NR-Uu interface or the 6G-Uu interface. When DC is supported, the communication node 220 can be connected to other base stations (e.g., base stations supporting 4G, 5G, and / or 6G functions) and the satellite 211, and can perform DC operations based on the technologies defined in the 4G, 5G, and / or 6G technical specifications.

[0073] The gateway 230 may be located at a ground location, a feed link may be established between the satellite 211 and the gateway 230, and a feed link may be established between the satellite 212 and the gateway 230. The feed link may be a radio link. When an ISL is not established between the satellite 211 and the satellite 212, a feed link between the satellite 211 and the gateway 230 may be established compulsorily. The communication between each of the satellite 211 and the satellite 212 and the gateway 230 may be performed based on an NR-Uu interface, a 6G-Uu interface, or an SRI. The gateway 230 may be connected to a data network 240.

[0074] like Figure 2b and Figure 2c As shown in the exemplary embodiment of FIG. 2 , a “core network” may exist between gateway 230 and data network 240 .

[0075] Figure 2bis a conceptual diagram showing a fourth exemplary embodiment of a non-terrestrial network, Figure 2c is a conceptual diagram illustrating a fifth exemplary embodiment of a non-terrestrial network.

[0076] like Figure 2b and Figure 2c As shown, the gateway can be connected to the core network, and the core network can be connected to the data network. The core network can support 4G communication technology, 5G communication technology and / or 6G communication technology. For example, the core network may include AMF, UPF, SMF, etc. The communication between the gateway and the core network can be performed based on the NG-C / U interface or the 6G-C / U interface. The functions of the base station can be performed by a satellite. That is, the base station can be located on a satellite. The base station located on the satellite can be a base station distributed unit (DU), and the base station centralized unit (CU) can be located within the NG-RAN or 6G-RAN. The payload can be processed by a base station located on the satellite. Base stations located on different satellites can be connected to the same core network. A satellite can have one or more base stations. In Figure 2b In non-terrestrial networks, it may not be possible to establish ISLs between satellites. Figure 2c In non-terrestrial networks, ISLs between satellites can be established.

[0077] On the other hand, the composition Figure 1a , Figure 1b , Figure 2a , Figure 2b and / or Figure 2c The entities of the non-terrestrial network shown (eg, satellite, base station, UE, communication node, gateway, etc.) may be configured as follows: In the present invention, the entity may be referred to as a communication node.

[0078] Figure 3 is a block diagram illustrating a first exemplary embodiment of communication nodes constituting a non-terrestrial network.

[0079] like Figure 3 As shown, the communication node 300 may include at least one processor 310, a memory 320, and a transceiver 330 connected to a network to perform communication. In addition, the communication node 300 may further include an input interface device 340, an output interface device 350, a storage device 360, etc. The components included in the communication node 300 may be connected through a bus 370 to communicate with each other.

[0080] However, each component included in the communication node 300 may be connected to the processor 310 through a separate interface or a separate bus instead of the common bus 370. For example, the processor 310 may be connected to at least one of the memory 320, the transceiver 330, the input interface device 340, the output interface device 350, and the storage device 360 ​​through a dedicated interface.

[0081] The processor 310 may execute at least one instruction stored in at least one of the memory 320 and the storage device 360. The processor 310 may refer to a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor on which the method according to the exemplary embodiment of the present invention is executed. Each of the memory 320 and the storage device 360 ​​may be configured as at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory 320 may be configured with at least one of a read-only memory (ROM) and a random access memory (RAM).

[0082] On the other hand, a communication node that performs communication in a communication network (eg, a non-terrestrial network) may be configured as follows. Figure 4 The communication nodes shown may be Figure 3 A specific exemplary embodiment of a communication node is shown.

[0083] Figure 4 is a block diagram illustrating a first exemplary embodiment of a communication node performing communications.

[0084] like Figure 4 As shown, each of the first communication node 400a and the second communication node 400b can be a base station or a UE. The first communication node 400a can send a signal to the second communication node 400b. The transmission processor 411 included in the first communication node 400a can receive data (e.g., data unit) from the data source 410. The transmission processor 411 can receive control information from the controller 416. The control information may include at least one of system information, RRC configuration information (e.g., information configured by RRC signaling), MAC control information (e.g., MAC CE) or PHY control information (e.g., DCI, SCI).

[0085] The transmit processor 411 may generate data symbols by performing processing operations on data (e.g., encoding operations, symbol mapping operations, etc.). The transmit processor 411 may generate control symbols by performing processing operations on control information (e.g., encoding operations, symbol mapping operations, etc.). In addition, the transmit processor 411 may generate synchronization / reference symbols for synchronization signals and / or reference signals.

[0086] The Tx MIMO processor 412 may perform spatial processing operations (e.g., precoding operations) on data symbols, control symbols, and / or synchronization / reference symbols. The output (e.g., symbol stream) of the Tx MIMO processor 412 may be provided to a modulator (MOD) included in the transceiver 413a to the transceiver 413t. The modulator may generate modulation symbols by performing processing operations on the symbol stream, and may generate signals by performing additional processing operations (e.g., analog conversion operations, amplification operations, filtering operations, up-conversion operations, etc.) on the modulation symbols. The signals generated by the modulators of the transceivers 413a to the transceivers 413t may be transmitted through the antennas 414a to the antennas 414t.

[0087] The signal transmitted by the first communication node 400a can be received at the antenna 464a to the antenna 464r of the second communication node 400b. The signal received at the antenna 464a to the antenna 464r can be provided to the demodulator (DEMOD) included in the transceiver 463a to the transceiver 463r. The demodulator (DEMOD) can obtain samples by performing processing operations (e.g., filtering operations, amplification operations, down-conversion operations, digital conversion operations, etc.) on the signal. The demodulator can perform additional processing operations on the samples to obtain symbols. The MIMO detector 462 can perform MIMO detection operations on the symbols. The receiving processor 461 can perform processing operations (e.g., deinterleaving operations, decoding operations, etc.) on the symbols. The output of the receiving processor 461 can be provided to the data sink 460 and the controller 466. For example, data can be provided to the data sink 460, and control information can be provided to the controller 466.

[0088] On the other hand, the second communication node 400b can send a signal to the first communication node 400a. The transmission processor 468 included in the second communication node 400b can receive data (e.g., data unit) from the data source 467, and perform processing operations on the data to generate data symbols. The transmission processor 468 can receive control information from the controller 466, and perform processing operations on the control information to generate control symbols. In addition, the transmission processor 468 can generate reference symbols by performing processing operations on reference signals.

[0089] The Tx MIMO processor 469 may perform spatial processing operations (e.g., precoding operations) on data symbols, control symbols, and / or reference symbols. The output (e.g., symbol stream) of the Tx MIMO processor 469 may be provided to a modulator (MOD) included in the transceiver 463a to the transceiver 463t. The modulator may generate modulation symbols by performing processing operations on the symbol stream, and may generate signals by performing additional processing operations (e.g., analog conversion operations, amplification operations, filtering operations, up-conversion operations) on the modulation symbols. The signals generated by the modulators of the transceivers 463a to the transceivers 463t may be transmitted via the antennas 464a to the antennas 464t.

[0090] The signal transmitted by the second communication node 400b may be received at the antenna 414a to the antenna 414r of the first communication node 400a. The signal received at the antenna 414a to the antenna 414r may be provided to a demodulator (DEMOD) included in the transceiver 413a to the transceiver 413r. The demodulator may obtain samples by performing a processing operation (e.g., a filtering operation, an amplification operation, a down-conversion operation, a digital conversion operation) on the signal. The demodulator may perform additional processing operations on the samples to obtain symbols. The MIMO detector 420 may perform a MIMO detection operation on the symbols. The receiving processor 419 may perform a processing operation (e.g., a deinterleaving operation, a decoding operation, etc.) on the symbols. The output of the receiving processor 419 may be provided to the data sink. 418 and controller 416. For example, data may be provided to data sink 418 and control information may be provided to controller 416.

[0091] Memory 415 and storage 465 may store data, control information and / or program codes. Scheduler 417 may perform scheduling operations for communications. Figure 4 The processors 411, 412, 419, 461, 468, 469 and the controllers 416 and 466 shown may be Figure 3 The processor 310 shown may be used to execute the methods described in the present invention.

[0092] Figure 5a is a block diagram illustrating a first exemplary embodiment of a transmit path, Figure 5b is a block diagram illustrating a first exemplary implementation of a receive path.

[0093] like Figure 5a and Figure 5bAs shown, the transmission path 510 can be implemented in a communication node that transmits a signal, and the receiving path 520 can be implemented in a communication node that receives a signal. The transmission path 510 may include a channel coding and modulation block 511, a serial-to-parallel (S to P) block 512, an N-point inverse fast Fourier transform (IFFT) block 513, a parallel-to-serial (P to S) block 514, a cyclic prefix (CP) adding block 515 and an up-converter (UC) 516. The receiving path 520 may include a down-converter (DC) 521, a CP deletion block 522, an S to P block 523, an N-point FFT block 524, a P to S block 525 and a channel decoding and demodulation block 526. Here, N may be a natural number.

[0094] In the transmission path 510, the information bits may be input to the channel coding and modulation block 511. The channel coding and modulation block 511 may perform coding operations (e.g., low-density parity check (LDPC) coding operations, polar coding operations, etc.) and modulation operations (e.g., quadrature phase shift keying (OPSK), quadrature amplitude modulation (QAM), etc.) on the information bits. The output of the channel coding and modulation block 511 may be a modulation symbol sequence.

[0095] The S to P block 512 may convert the frequency domain modulation symbols into parallel symbol streams to generate N parallel symbol streams. N may be an IFFT size or an FFT size. The N-point IFFT block 513 may generate a time domain signal by performing an IFFT operation on the N parallel symbol streams. The P to S block 514 may convert the output (e.g., parallel signals) of the N-point IFFT block 513 into a serial signal to generate a serial signal.

[0096] The CP adding block 515 may insert a CP into the signal. The UC 516 may up-convert the frequency of the output of the CP adding block 515 to a radio frequency (RF) frequency. In addition, the output of the CP adding block 515 may be filtered in baseband before up-conversion.

[0097] The signal transmitted from the transmission path 510 may be input to the reception path 520. The operation in the reception path 520 may be an operation opposite to the operation in the transmission path 510. The DC 521 may down-convert the frequency of the received signal to the baseband frequency. The CP removal block 522 may remove the CP from the signal. The output of the CP removal block 522 may be a serial signal. The S to P block 523 may convert the serial signal into a parallel signal. The N-point FFT block 524 may generate N parallel signals by performing an FFT algorithm. The P to S block 525 may convert the parallel signal into a modulation symbol sequence. The channel decoding and demodulation block 526 may perform a demodulation operation on the modulation symbol, and may recover the data by performing a decoding operation on the result of the demodulation operation.

[0098] exist Figure 5a and Figure 5b In the present invention, discrete Fourier transform (DFT) and inverse DFT (IDFT) can be used to replace FFT and IFFT. Figure 5a and Figure 5b Each of the blocks (eg, components) in the embodiment may be implemented by at least one of hardware, software, or firmware. Figure 5a and Figure 5b Some blocks in the can be implemented by software, and other blocks can be implemented by hardware or a combination of hardware and software. Figure 5a and Figure 5b In the , a block can be subdivided into multiple blocks, multiple blocks can be integrated into one block, some blocks can be omitted, and blocks that support other functions can be added.

[0099] On the other hand, the NTN reference scenario may be defined as shown in Table 1 below.

[0100] [Table 1]

[0101] NTN shown in Figure 1 NTN shown in Figure 2 GEO Scenario A Scenario B LEO (Steering Beam) Scenario C1 Scenario D1 LEO (beam that moves with the satellite) Scenario C2 Scene D2

[0102] when Figure 1a and / or Figure 1b When the satellite 110 in the NTN shown is a GEO satellite (e.g., a GEO satellite supporting transparency functionality), this may be referred to as "Scenario A". Figure 2a , Figure 2b and / or Figure 2c When satellite 211 and satellite 212 in the NTN shown are GEO satellites (e.g., GEOs supporting regeneration functionality), this may be referred to as "Scenario B". Figure 1a and / or Figure 1b When the satellite 110 in the NTN shown is a LEO satellite with a steerable beam, this may be referred to as "Scenario C1". Figure 1a and / or Figure 1b When the satellite 110 in the NTN shown is a LEO satellite with a beam that moves with the satellite, this may be referred to as "Scenario C2". Figure 2a , Figure 2b and / or Figure 2c When satellite 211 and satellite 212 in the NTN shown are LEO satellites with steerable beams, this may be referred to as "Scenario D1". Figure 2a , Figure 2b and / or Figure 2c When satellite 211 and satellite 212 in the NTN shown are LEO satellites with beams that move with the satellites, this may be referred to as "scenario D2".

[0103] Parameters for the NTN reference scenario defined in Table 1 may be defined as shown in Table 2 below.

[0104] [Table 2]

[0105]

[0106]

[0107] In addition, in the scenario defined in Table 1, the delay constraint may be defined as shown in Table 3 below.

[0108] [Table 3]

[0109]

[0110] Figure 6a is a conceptual diagram showing a first exemplary embodiment of a protocol stack for a user plane in a non-terrestrial network based on a transparent payload, Figure 6b is a conceptual diagram showing a first exemplary embodiment of a protocol stack for a control plane in a non-terrestrial network based on transparent payload. Figure 6a and Figure 6b As shown, user data can be sent and received between the UE and the core network (e.g., UPF), and control data (e.g., control information) can be sent and received between the UE and the core network (e.g., AMF). Each of the user data and the control data can be sent and received via a satellite and / or a gateway. Figure 6a The protocol stack of the user plane shown can be applied identically or similarly to a 6G communication network. Figure 6b The control plane protocol stack shown can be applied identically or similarly to a 6G communication network.

[0111] Figure 7a is a conceptual diagram illustrating a first exemplary embodiment of a protocol stack for a user plane in a non-terrestrial network based on a regenerative payload, Figure 7bis a conceptual diagram illustrating a first exemplary embodiment of a protocol stack for a control plane in a non-terrestrial network based on a regenerative payload.

[0112] like Figure 7a and Figure 7b As shown, each of user data and control data (e.g., control information) can be sent and received through an interface between a UE and a satellite (e.g., a base station). User data can refer to a user protocol data unit (PDU). A protocol stack of a satellite radio interface (SRI) can be used to send and receive user data and / or control data between a satellite and a gateway. User data can be sent and received between a satellite and a core network through a general packet radio service (GPRS) tunneling protocol (GTP)-U tunnel.

[0113] On the other hand, in a non-terrestrial network, the base station may transmit system information (e.g., SIB19) including satellite assistance information for NTN access. The UE may receive the system information (e.g., SIB19) from the base station, identify the satellite assistance information included in the system information, and perform communication (e.g., non-terrestrial communication) based on the satellite assistance information. SIB19 may include the information elements defined in Table 4 below.

[0114] [Table 4]

[0115]

[0116]

[0117] The NTN-Config defined in Table 4 may include the information elements defined in Table 5 below.

[0118] [Table 5]

[0119]

[0120] The EphemerisInfo defined in Table 5 may include the information elements defined in the following Table 6.

[0121] [Table 6]

[0122]

[0123] On the other hand, in non-terrestrial networks, the link quality may be reduced due to the long distance between the satellite and the terminal and the large Doppler shift caused by high-speed movement. To overcome this, research on coverage enhancement (CE) has been actively discussed since Release 17. In areas with low elevation angles, the degradation of link quality may become more obvious. In addition, in cities and suburbs with many high-rise buildings, the degradation of link quality may be more obvious. In the uplink, improving the reception performance of the random access channel (RACH) used in the initial access process has become a key issue in Release 17, and performance enhancement methods using polarization may be discussed a lot. The present invention proposes a method for improving RACH performance by additionally applying polarization to the preamble. The method proposed in the present invention can support performance enhancement of terminals (e.g., handheld terminals) using antennas with lower antenna gain. In addition, the method proposed in the present invention can improve the performance of the link when the link budget is low.

[0124] According to the present invention, the non-terrestrial network can increase the number of preamble combinations by additionally applying polarization. In addition, according to the present invention, the non-terrestrial network can reduce the probability of contention that occurs when multiple terminals select the same preamble sequence. In addition, according to the present invention, the non-terrestrial network can increase the number of random access channel combinations by utilizing polarization in repeated transmissions of the random access channel. In addition, according to the present invention, the non-terrestrial network can expect to improve reception performance through diversity.

[0125] On the other hand, the 94th 3rd Generation Partnership Project (3GPP) Radio Access Network (RAN) Technology Plenary Meeting in December 2021 discussed coverage enhancement, as follows.

[0126] ○ The following items were discussed as examples of areas to be considered in the next phase of research. In addition, the RAN Technical Plenary discussed the evaluation of NTN-specific coverage issues that have been identified as practical research items.

[0127] - NTN-specific repetition enhancements go beyond the techniques covered in the coverage enhancement work item for associated channels in Release 17.

[0128] - NTN specific techniques to improve diversity and / or reduce polarization losses.

[0129] On the other hand, at the 109-e meeting of the RAN Technology Plenary Meeting Working Group (WG) 1 in April 2022, LG Electronics mainly discussed the following potential enhancement points as initial access procedures.

[0130] ○ In the Release 17 coverage enhancement (CE) research project phase, coverage enhancement for uplink signals / channels during initial access may be required. Therefore, repetition of the PRACH preamble and repetition of the Msg3 physical uplink shared channel (PUSCH) may be considered.

[0131] o It may be desirable to consider introducing both repeated PRACH preamble transmissions and repeated Msg3 PUSCH transmissions in Release 18 NTN.

[0132] ○ However, since NR does not support repeated PRACH preamble transmission, the following discussion points may need to be considered to support repeated PRACH preamble transmission.

[0133] ○ It may be necessary to determine the maximum number of repetitions. For example, the maximum number of repetitions of the PRACH preamble can be determined at a level similar to the maximum number of repetitions of the Msg3 PUSCH (e.g., 8). In addition, the maximum number of repetitions can be provided to the UE through higher layer signaling (e.g., SIB).

[0134] On the other hand, at the 109-e meeting of the RAN Technology Plenary Meeting WG1 held in April 2022, Lenovo proposed the following diversity-based coverage enhancement (CE) method.

[0135] ○ Frequency hopping is already supported in legacy NR releases and can continue to be used to provide frequency domain diversity in NR NTN. Diversity using different satellites or different carriers has been mentioned in previous discussions related to the specific characteristics of NTN. However, this scenario is somewhat complex and considering the limited TUs, it may not be preferred to study this type of diversity in Release 18.

[0136] ○ Polarization-based diversity may also be considered. Polarization may support both the initial access process and data transmission in the Radio Resource Control (RRC) connected state. In the initial access process, synchronization signal blocks (SSBs) with different polarization patterns may be used. In the RRC connected state, different polarization patterns may be used for at least different time domain resources to achieve diversity gain.

[0137] On the other hand, at the 109-e meeting of the RAN Technology Plenary Meeting WG1 in April 2022, Sony discussed the following content to improve NTN NR coverage.

[0138] ○ Polarization indication for NTN communications has been discussed in Release 17, where explicit indication of downlink polarization by the network is supported based on SIB. At the same time, information about uplink polarization can be indicated by the network in the SIB. When no information about uplink polarization is provided, the UE can assume that the polarization of both uplink and downlink is the same. In terms of polarization mode, right-hand circular polarization (RHCP), left-hand circular polarization (LHCP) or linear polarization can be indicated in the SIB for both downlink and / or uplink polarization information.

[0139] 5G terminals can select random preambles during the RACH process to obtain uplink synchronization. Each preamble can be associated with a random access radio network temporary identifier (RA-RNTI). The terminal can send the random preamble as Msg1 to the base station. The base station can receive the random preamble from the terminal. In this case, the terminal and the base station can derive the RA-RNTI based on the time and frequency position of the RACH occasion (RACHoccasion, RO) when Msg1 is sent. Subsequently, the base station can generate a random access response (RAR) in response to the random preamble received from the terminal.

[0140] The RAR may be transmitted via a downlink-shared channel (DL-SCH) as a transmission channel and may be mapped to a physical downlink shared channel (PDSCH). For transmission of the PDSCH carrying the RAR, the base station may scramble the cyclic redundancy check (CRC) bits of the PDCCH using the RA-RNTI. The RA-RNTI may be calculated as in Equation 1.

[0141] [Equation 1]

[0142] RA-RNTI=1+s_id+14×t_id+14×80×f_id+14×80×8×ul_carrier_id

[0143] In Equation 1, s_id (0≤s_id<14) may represent the index of the first symbol of the RO, and t_id (0≤t_id<80) may represent the index of the first time slot (e.g., the starting time slot) of the RO within the system frame. In an exemplary embodiment, the symbol may refer to an OFDM symbol. t_id may be determined based on a subcarrier spacing (SCS). f_id (0≤f_id<8) may represent the index of the RO in the frequency domain, and ul_carrier_id may represent the uplink (UL) carrier on which the PRACH preamble is transmitted. If the UL carrier on which the PRACH preamble is transmitted is a normal uplink (NUL), ul_carrier_id may be set to 0. If the UL carrier on which the PRACH preamble is transmitted is a supplementary uplink (SUL), ul_carrier_id may be set to 1.

[0144] For RACH operation, the terminal may receive system information including the following from the base station:

[0145] ○PRACH transmission parameter configuration

[0146] -PRACH preamble format

[0147] -Time resources

[0148] -Frequency resources

[0149] ○ Parameters used to determine the root sequence and cyclic shift in the PRACH preamble set

[0150] - Index to the logical root sequence list

[0151] - Circular shift

[0152] - Set type (unrestricted, restricted set A, or set B)

[0153] Figure 8 is a sequence diagram illustrating a first exemplary embodiment of a method of performing a random access procedure in a non-terrestrial network.

[0154] like Figure 8 As shown, the base station may send system information and / or a control message including configuration information for a random access procedure (i.e., RACH configuration information) to the terminal (S810). Here, the system information may be common system information used by multiple base stations or base station-specific system information (e.g., cell-specific system information). The control message may be a dedicated control message.

[0155] The system information may be configured for each base station, each beam group, or each beam. The system information may include configuration information for a random access procedure. The configuration information for a random access procedure may include information about the polarization to be used by the terminal to send a preamble (i.e., polarization information). The polarization information may include polarization types available for use by the terminal. The polarization types may include left-hand circular polarization (LHCP), right-hand circular polarization (RHCP), and linear polarization (LP). The polarization information may include information about a polarization mode (i.e., polarization mode information). Reference Fig.10 Details related to polarization mode information are described. In addition, the polarization information may include information about a preamble sequence group that can be transmitted using LHCP, information about a preamble sequence group that can be transmitted using RHCP, and information about a preamble sequence group that can be transmitted using linear polarization.

[0156] In addition, the configuration information for the random access procedure may include information about the transmission frequency of the physical layer, information about the system bandwidth, information about the subcarrier spacing, configuration information of the beam according to the beamforming technology (e.g., beam width, beam index), variable configuration information of radio resources in the frequency domain and / or time domain (e.g., reference value of the radio resource, offset, etc.), or one or more of information about an inactive (or unused) radio resource area / period. In addition, the configuration information for the random access procedure may include preamble information indicating an available preamble.

[0157] Accordingly, the terminal may receive system information and / or control messages from the base station. The terminal may identify available polarization types and available preambles. Then, the terminal may select a polarization from the available polarization types and a preamble from the available preambles.

[0158] Subsequently, the terminal may send RA MSG1 including the selected random access preamble (ie, RA preamble) to the base station using the selected polarization through a radio resource (e.g., a physical random access channel (PRACH)) configured by the base station (S820). In the four-step random access procedure, message 1 including the RA preamble may be referred to as "RA MSG1", and the RA preamble in the four-step random access procedure may be referred to as a "four-step RA preamble".

[0159] To further describe this in detail, the terminal may randomly select a code sequence (e.g., preamble, signature) defined for a random access procedure, and may send an RA MSG1 including the selected code sequence. In a contention-based random access (CBRA) procedure, the terminal may randomly select a preamble. In a contention-free random access (CFRA) procedure, the base station may pre-allocate a preamble to the terminal. The pre-allocation of the RA preamble may mean that an index of the RA preamble of the RA MSG1, shielding information, etc. are exclusively allocated to the terminal. In this case, the terminal may perform a random access procedure (e.g., CFRA procedure) without competing with other terminals.

[0160] The base station may receive RA MSG1 from the terminal. The base station may identify the polarization type used by the terminal and may identify the preamble used. The base station may generate RA MSG2 in response to RA MSG1 and may send RA MSG2 to the terminal (S830). In the four-step random access process, RA MSG2 may refer to message 2, a random access response (RAR) or an RA response message. The base station may determine the required information of the terminal based on the RA MSG1 received at step S820 or the radio resource receiving RA MSG1. In this case, the base station may send the required information to the terminal at step S830.

[0161] The determination of the required information of the terminal may refer to confirming "system information transmission request based on the on-demand request of the terminal", "downlink data transmission request due to the update of the terminal firmware or required software", or "uplink resource allocation request" based on the information received in step S810 (e.g., preamble index, specific signal sequence (e.g., sequence, signature) for uplink resource request, specific field value of uplink control channel). In this case, uplink radio resource allocation information may be sent in step S830. Alternatively, RA MSG2 may be sent through PDCCH or physical downlink shared channel (PDSCH).

[0162] In step S830, the base station may transmit only the PDCCH (e.g., DCI) without transmitting the RA response message (e.g., RA MSG2) through the PDSCH. In this case, the DCI may include uplink resource allocation information (e.g., scheduling information), transmission timing adjustment information (e.g., timing advance (TA) value, TA command), transmission power control information, backoff information, beam configuration information, TCI state information, configured scheduling (CS) state information, state transition information, PUCCH configuration information, an index of the RA MSG1 received in step S820 (e.g., preamble index), and one or more of the uplink resource allocation information for the RA MSG3 transmission in step S840.

[0163] Here, the beam configuration information may indicate the activation or deactivation of a specific beam. The TCI state information may indicate the activation or deactivation of a specific TCI state. The CS state information may indicate the activation or deactivation of radio resources allocated using the CS scheme. The state transition information may indicate the transition of the operating state of the terminal. The state transition information may indicate a transition from a specific operating state to a radio resource control (RRC) idle state, an RRC connected state, or an RRC inactive state. Alternatively, the state transition information may indicate maintaining the current operating state. The PUCCH configuration information may include allocation information for scheduling request (SR) resources. Alternatively, the PUCCH configuration information may indicate the activation or deactivation of SR resources.

[0164] If the base station transmits only the PDCCH (e.g., DCI) but does not transmit the RA MSG2 at step S830, the terminal can recognize that there is no RA MSG2 transmitted through the PDSCH by using the control information included in the PDCCH, the DCI format included in the PDCCH, and / or the scheduling identifier used to transmit the PDCCH. The base station can transmit the scheduling information of the RA MSG2 to the terminal using the RA-RNTI. For example, the CRC bits of the DCI including the scheduling information of the RA MSG2 can be scrambled using the RA-RNTI, and the DCI can be transmitted through the PDCCH.

[0165] At this time, the terminal and the base station can use Equation 2 to generate the RA-RNTI.

[0166] [Equation 2]

[0167] RA-RNTI=1+s_id+14×t_id+14×80×f_id+14×80×8×ul_carrier_id+14×80×8×2×pol_id

[0168] In Equation 2, s_id (0≤s_id<14) may indicate the index of the first symbol of the RO, and t_id (0≤t_id<80) may indicate the index of the first time slot (e.g., the starting time slot) of the RO within the system frame. In an exemplary embodiment, the symbol may refer to an OFDM symbol. t_id may be determined based on the SCS. f_id (0≤f_id<8) may indicate the index of the RO in the frequency domain, and ul_carrier_id may indicate the UL carrier on which the PRACH preamble is transmitted. If the UL carrier on which the PRACH preamble is transmitted is NUL, ul_carrier_id may be set to 0. If the UL carrier on which the PRACH preamble is transmitted is SUL, ul_carrier_id may be set to 1. pol_id may be configured as a polarization identifier (ID) and may be used similarly to carrier_id. For example, if the polarization is LP, pol_id may be 0. If the polarization is CP, pol_id may be 1.

[0169] On the other hand, the terminal may receive RA MSG2 from the base station. At this time, the terminal may generate RA-RNTI using Equation 2. Then, the terminal may descramble RA MSG2 and decode DCI using the generated RA-RNTI, and generate RA MSG3 (i.e., message 3) including information about the terminal itself (i.e., terminal information), which may then be sent to the base station (S840). The terminal information may include one or more of a terminal identifier, capabilities, attributes, mobile status or location information of the terminal, a reason for radio access, uplink data size information (e.g., buffer status report (BSR)), connection configuration request information, or uplink data. In addition, at step S840, the terminal may send information requesting the information required by the terminal to the base station.

[0170] In addition, using RA MSG3, the terminal can send one or more of beam failure recovery request information, BWP change request information, BWP deactivation / activation request information, measurement result information of a base station (or cell) in a carrier aggregation (CA) environment, and a request for CA activation / deactivation. When a random access procedure for beam recovery is performed after beam failure detection, the beam failure recovery request information may request execution of a beam recovery procedure based on beam measurement results. In this case, the terminal may send beam-specific measurement result information and / or TCI status information for configuring a new beam to the base station.

[0171] "BWP change request information" or "BWP deactivation / activation request information" may each include one or more of "request information for changing the activated BWP based on the measurement result of the BWP", "measurement result information of the inactive BWP", and "preferred activated BWP information of the terminal". In addition, RA MSG3 may include one or more of a BWP identifier, a base station (or cell) identifier, and configured beam information (for example, TCI status, CSI-RS index, SS / PBCH index that can be used to identify the beam). RA MSG3 may be sent in the form of a MAC CE or an RRC message.

[0172] If RA MSG2 is received based on PDCCH (or DCI) at step S830, the terminal may perform an operation according to the information element included in PDCCH (or DCI). The information element included in PDCCH (or DCI) may include "request information for changing the operating state of the terminal", "request information for maintaining the operating state of the terminal", "information indicating activation or deactivation of a beam", "information indicating activation or deactivation of a TCI state", and "information indicating activation or deactivation of a CS state" One or more. In this case, the random access procedure may be terminated without performing step S840.

[0173] In step S830, RA MSG2 may be received based on PDCCH or DCI, and if uplink radio resources for RAMSG3 are not allocated, the terminal may wait until allocation information of uplink radio resources for RA MSG3 is received. If allocation information of uplink radio resources for RA MSG3 is received before the expiration of the pre-configured timer, the terminal may send RA MSG3 to the base station using the uplink radio resources. On the other hand, if allocation information of uplink radio resources for RA MSG3 is not received until the expiration of the pre-configured timer, the terminal may perform the random access procedure again. In other words, the terminal may perform step S820 again.

[0174] At step S850, the base station may send the downlink information requested by the terminal. Alternatively, the base station may send downlink data or a control message to the terminal. At step S850, the base station may send the terminal identifier received from the terminal (e.g., the terminal identifier received at step S840) to the terminal. Message 4 sent by the base station at step S850 may be referred to as "RAMSG4". The base station may use RA MSG2 to send resource allocation information (e.g., scheduling information) for sending RA MSG3 to the terminal. The scheduling information may include at least one of an identifier of the base station sending the scheduling information, a beam index, an identifier for distinguishing the scheduling information, resource allocation information, MCS information, and resource allocation information for sending feedback information (e.g., ACK or NACK) indicating whether the scheduling information is received. The resource allocation information may include frequency domain resource allocation information (e.g., transmission bandwidth information and subcarrier allocation information) and / or time domain resource allocation information (e.g., frame index, subframe index, slot index, symbol index, transmission segment, and transmission timing).

[0175] Fig. 9 is a sequence diagram illustrating a second exemplary embodiment of a method of performing a random access procedure in a non-terrestrial network.

[0176] like Fig. 9 As shown, the base station may send system information and / or a control message including RACH configuration information to the terminal (S910). Here, the system information may be common system information used by multiple base stations or base station-specific system information (e.g., cell-specific system information). The control message may be a dedicated control message.

[0177] The system information may be configured for each base station, each beam group, or each beam. The system information may include RACH configuration information. The RACH configuration information may include information about the polarization to be used by the terminal to send the preamble (i.e., polarization information). Here, the polarization information may include polarization types available for use by the terminal. The polarization types may include left-hand circular polarization, right-hand circular polarization, and linear polarization. The polarization information may include information about the polarization mode (i.e., polarization mode information). Fig.10 Details related to polarization mode information are described. In addition, the polarization information may include information about a preamble sequence group that can be transmitted using left-hand circular polarization, information about a preamble sequence group that can be transmitted using right-hand circular polarization, and information about a preamble sequence group that can be transmitted using linear polarization.

[0178] In addition, the RACH configuration information may include information about the transmission frequency of the physical layer, information about the system bandwidth, information about the subcarrier spacing, configuration information of the beam according to the beamforming technology (e.g., beam width and beam index), variable configuration information of radio resources in the frequency domain and / or time domain (e.g., reference value of the radio resource, offset, etc.), or at least one of information about an inactive (or unused) radio resource area / period. In addition, the RACH configuration information may include preamble information indicating an available preamble.

[0179] Accordingly, the terminal may receive system information and / or control messages from the base station. The terminal may identify available types of polarizations and preambles. Subsequently, the terminal may select a polarization from the available types of polarizations and select a preamble. The terminal may send a RA MSG-A (S920) including the selected preamble to the base station using the selected polarization by utilizing the radio resources configured by the base station. The RA MSG-A may include an RA preamble and a terminal identifier (e.g., a user equipment (UE) ID or a cell RNTI (C-RNTI)). In addition, the RA MSG-A may further include uplink data and / or control information. In the two-step random access process, message 1 may be referred to as "RA MSG-A", and the RA MSG-A may be distinguished from the RA MSG1 in the four-step random access process.

[0180] RA MSG-A may include an RA preamble and an RA payload. In a two-step random access process, the RA preamble may be referred to as a "two-step RA preamble", and the RA payload may be referred to as a "two-step RA payload". The RA preamble of the RA MSG-A may be selected by the MAC layer of the terminal. The RA payload of the RA MSG-A may be generated by the MAC layer or the RRC layer. The RA preamble selected by the MAC layer of the terminal and the RA payload generated by the MAC layer or the RRC layer of the terminal may be delivered to the physical layer. The RA payload of the RA MSG-A may include at least one of a terminal identifier (e.g., UE ID or C-RNTI), uplink data, and control information. The control information may include at least one of a BSR, measurement result information (e.g., quality information), a BFR request information, an RLF report information, a request information for RRC connection establishment, a request information for RRC connection reconstruction, a recovery request information, the location information of the terminal (e.g., a location estimated using a GPS signal, a positioning measurement scheme, or an embedded sensor), or a request information for system information transmission. When the CBRA procedure or the CFRA procedure is performed, the RA payload may include the terminal identifier.The uplink radio resources used to transmit the RA preamble may be configured independently of the uplink radio resources used to transmit the RA payload.

[0181] In order to configure the transmission resources for the RA preamble of the RA MSG-A differently from the transmission resources for the RA payload of the RA MSG-A, the uplink radio resources for transmitting the RA payload of the RA MSG-A (for example, the PUSCH configured for transmitting the RA payload of the RA MSG-A) may be configured to correspond to the RA preamble of the RA MSG-A. In other words, a mapping relationship may be established between the uplink radio resources for transmitting the RA preamble of the RA MSG-A and the uplink radio resources for transmitting the RA payload of the RA MSG-A.

[0182] The base station may receive a RA MSG-A from the terminal and obtain an RA preamble and an RA payload included in the RA MSG-A. In addition, the base station may obtain information about the polarization type used by the terminal. In addition, the base station may obtain at least one of a terminal identifier, uplink data, and control information from the RA payload. The base station may generate a RA MSG-B (e.g., message 2 or RAR) in response to the RA MSG-A and send the RA MSG-B to the terminal (S930). The terminal may receive a RAMSG-B from the base station and identify the information elements included in the RA MSG-B. The RA MSG-B may include a backoff indicator (BI), uplink radio resource allocation information, information about the RA preamble of the RA MSG-A (e.g., RA preamble index), transmission timing adjustment information (e.g., TA value or TA command), a scheduling identifier (e.g., C-RNTI or temporary cell (TC)-RNTI), or a terminal identifier for contention resolution (e.g., UE contention resolution ID) at least one.

[0183] When RA MSG-B is scheduled by the C-RNTI assigned to the terminal, or when RA MSG-B includes the terminal identifier (eg, UE contention resolution ID) included in RA MSG-A, the terminal can determine that the contention has been resolved. In other words, the terminal can determine that the two-step random access procedure has been completed.

[0184] When the CRC bits of the DCI containing scheduling information for the PDSCH carrying the RA MSG-B (e.g., the RAR of the RA MSG-A) are scrambled by the C-RNTI, and the RA MSG-B including the TA information and / or the UL authorization is received within the RAR window (or before the timer expires), the terminal can determine that the contention in the two-step random access process has been resolved. Here, the TA information can be a TA value or a TA command. A specific field (or bit) within the PDCCH (e.g., DCI or UCI) can indicate that the RA MSG-B scheduled by the corresponding PDCCH is a RA MSG-B scheduled by the C-RNTI. Alternatively, a field in the MAC subheader or logical channel identifier (LCID) of the MAC CE for transmitting the RA MSG-B can indicate that the RA MSG-B scheduled by the PDCCH is a RA MSG-B scheduled by the C-RNTI.

[0185] In the four-step random access process, the RAR window may start from the transmission completion time of RA MSG1. In the two-step random access process, the RAR window may start from the transmission completion time of the RA payload of RA MSG-A. If a RA MSG-B (e.g., a RA MSG-B scheduled by C-RNTI) including TA information and / or UL grant is not received within the RAR window (or before the timer expires), the terminal may determine that the contention in the two-step random access process has not been resolved. If a RA MSG-B scheduled by C-RNTI is sent in response to RA MSG-A in the two-step random access process, the PDCCH (e.g., DCI or UCI) may include TA information, an indicator, etc., indicating that the corresponding PDCCH contains scheduling information in response to RA MSG-A. RA MSG-B may be sent in the form of a MAC message (e.g., MAC CE) or an RRC message. If RA MSG-B is sent in the form of a MAC message, the RRC layer of the base station that has obtained the information of RA MSG-A can pass (one or more) parameters to be included in RA MSG-B to the MAC layer of the base station, and the MAC layer of the base station can generate RAMSG-B in the form of MAC CE. RA MSG-B can include the terminal identifier obtained through the RA payload of RA MSG-A.

[0186] In step S930, the base station may transmit a PDCCH for scheduling uplink radio resources, a PDCCH (e.g., DCI) for RAR (e.g., RAMSG-B), or a RA MSG-B. The RA MSG-B may be transmitted through the PDSCH. If only the PDCCH is transmitted in step S930, the PDCCH may include allocation information (e.g., scheduling information) of uplink radio resources for the terminal, transmission timing adjustment information (e.g., TA information), transmission power control information, backoff information, beam configuration information, TCI state information, CS state information, state transition information, PUCCH configuration information, an index of an RA preamble included in the RA MSG-A, or one or more of allocation information of radio resources for transmission of an RA payload in the RA MSG-A.

[0187] In addition, if only PDCCH is sent in step S930, the terminal can recognize that RA MSG2 transmitted based on PDSCH does not exist based on the DCI format of PDCCH and / or the aforementioned PDCCH configuration information. Beam configuration information may indicate activation or deactivation of a specific beam. TCI state information may indicate activation or deactivation of a specific TCI state. CS state information may indicate activation or deactivation of radio resources allocated by the CS scheme. State transition information may indicate a transition from a current operating state to an RRC idle state, an RRC inactive state, or an RRC connected state. Alternatively, the state transition information may indicate maintaining the current operating state. PUCCH configuration information may be allocation information of SR transmission resources. Alternatively, PUCCH configuration information may indicate activation or deactivation of SR transmission resources.

[0188] By sending only the PDCCH, the base station may send the aforementioned control information through the PDSCH at step S930. At step S940, the control message sent through the PDSCH may include one or more of allocation information of uplink radio resources (e.g., scheduling information), transmission timing adjustment information (e.g., TA information), transmission power control information, backoff information, beam configuration information, TCI state information, configured scheduling (CS) state information, state transition information, PUCCH configuration information, an index of an RA preamble included in an RA MSG-A, or allocation information of uplink radio resources for transmitting uplink data and / or control messages.

[0189] In the process of generating / transmitting RA MSG-B, the base station may transmit DCI including scheduling information for transmission of RA MSG-B using RA-RNTI or a scheduling identifier (e.g., C-RNTI) allocated to the terminal. That is, the CRC bits of the DCI may be scrambled by the RA-RNTI or C-RNTI. The base station may send RA MSG-B to the terminal using the PDSCH indicated by the DCI.

[0190] If the terminal successfully receives the RA MSG-B from the base station, the two-step random access procedure may be terminated. The terminal receiving the RAMSG-B may transmit uplink data and / or control messages to the base station using uplink scheduling information (eg, scheduling information included in the RA MSG-B) (S940).

[0191] Fig.10 It is shown that the use Figure 8 and Fig. 9 A conceptual diagram of a first exemplary embodiment of a process for sending a preamble code in a polarization mode in FIG.

[0192] like Fig.10 As shown, the satellite base station 1010 may send system information and / or control messages including RACH configuration information to the terminals 1020A to 1020D. Here, the system information may be common system information used by multiple satellite base stations, or satellite base station-specific system information (e.g., cell-specific system information). The control message may be a dedicated control message. The system information may be configured for each satellite base station, each beam group, or each beam. The system information may include RACH configuration information. The RACH configuration information may include information about the polarization mode to be used by the terminals 1020A to 1020D for repeating the transmission of the preamble. Here, the polarization mode information may be information about the order of polarization types to be used when the terminal repeats the transmission of the preamble. In this case, the polarization types may include left-hand circular polarization (LHCP) and right-hand circular polarization (RHCP). In addition, the information about the order of polarization types may indicate the order of polarization types used by the terminal when repeating the transmission of the preamble. Examples of such an order may include "RRRL", "RRLR", "RLRR", and "LRRR". Here, "R" may represent right-hand circular polarization, and "L" may represent left-hand circular polarization. In addition, the polarization type may include vertical polarization and horizontal polarization. Then, the information about the order of polarization types may represent the order of polarization types used by the terminal when repeatedly transmitting the preamble, and examples include "VVVH", "VVHV", "VHVV", and "HVVV". Here, "V" may represent vertical polarization, and "H" may represent horizontal polarization.

[0193] In addition, the RACH configuration information may include information about the transmission frequency of the physical layer, information about the system bandwidth, information about the subcarrier spacing, configuration information of the beam according to the beamforming technology (e.g., beam width, beam index), variable configuration information of radio resources in the frequency domain and / or time domain (e.g., reference value of the radio resource, offset, etc.), and one or more of information about an inactive (or unused) radio resource area / period. In addition, the RACH configuration information may include preamble information indicating an available preamble.

[0194] Each of the terminals 1020A to 1020D may repeatedly transmit the preamble using RHCP or LHCP. In this case, the satellite base station 1010 may have a separate receiver for each polarization. Alternatively, the satellite base station 1010 may use a single receiver to handle both polarizations. Each of the terminals 1020A to 1020D may repeatedly transmit the preamble using RHCP or LHCP, for example, four times. In this case, each of the terminals 1020A to 1020D may use a different preamble sequence. In this case, the satellite base station 1010 may distinguish each of the terminals 1020A to 1020D based on the preamble sequence. Alternatively, the terminals 1020A to 1020D may repeatedly transmit the preamble using the same preamble sequence. In this case, the satellite base station 1010 may further distinguish and identify the terminals 1020A to 1020D based on the polarization mode used.

[0195] For example, the satellite base station 1010 may include information about the polarization mode "RRRL" to be used in the RACH configuration information, and send the RACH configuration information to the first terminal 1020A. Then, the first terminal 1020A may receive the RACH configuration information including the information about the polarization mode "RRRL" to be used from the satellite base station 1010. In addition, the satellite base station 1010 may include information about the polarization mode "RRLR" in the RACH configuration information, and send the RACH configuration information to the second terminal 1020B. Then, the second terminal 1020B may receive the RACH configuration information including the information about the polarization mode "RRLR" from the satellite base station 1010. In addition, the satellite base station 1010 may include information about the polarization mode "RLRR" in the RACH configuration information, and send the RACH configuration information to the third terminal 1020C. Then, the third terminal 1020C may receive the RACH configuration information including the information about the polarization mode "RLRR" from the satellite base station 1010. In addition, the satellite base station 1010 may include information about the polarization mode "LRRR" in the RACH configuration information and transmit the RACH configuration information to the fourth terminal 1020D. Then, the fourth terminal 1020D may receive the RACH configuration information including the information about the polarization mode "LRRR" from the satellite base station 1010.

[0196] Accordingly, the first terminal 1020A may apply polarization in the order of RHCP-RHCP-RHCP-LHCP to repeat the transmission of the preamble four times. The second terminal 1020B may apply polarization in the order of RHCP-RHCP-LHCP-RHCP to repeat the transmission of the preamble four times. The third terminal 1020C may apply polarization in the order of RHCP-LHCP-RHCP-RHCP to repeat the transmission of the preamble four times. The fourth terminal 1020D may apply polarization in the order of LHCP-RHCP-RHCP-RHCP to repeat the transmission of the preamble four times.

[0197] As described above, each of the terminals 1020A to 1020D may repeatedly transmit a preamble to the satellite base station 1010 based on the information about the polarization mode received from the satellite base station 1010. Then, the satellite base station 1010 may repeatedly receive the preamble from the terminal and identify the used polarization mode applied during the transmission of the preamble. In this case, the satellite base station 1010 may distinguish the transmitting terminal based on the identified polarization mode, as shown in Table 7.

[0198] [Table 7]

[0199]

[0200]

[0201] In Table 7, "x" may indicate a situation where the receivers in the satellite base station 1010 responsible for each polarization detect signals transmitted with a polarization and a reception intensity P equal to or greater than a predetermined threshold P_TH. On the other hand, "0" in Table 7 may indicate a situation where the receivers in the satellite base station 1010 responsible for each polarization do not detect signals transmitted with a reception intensity equal to or greater than the predetermined threshold with the corresponding polarization. In this case, the satellite base station 1010 may ignore the noise N and polarization mismatch to simplify the operation. In order for the satellite base station 1010 to receive the RACH preamble, P may need to be greater than P_TH (P > P_TH). In the part marked with "x" in Table 7, N < P < P_TH may be applicable. It may be difficult for the satellite base station 1010 to avoid both false detection and misdetection conditions by receiving only a single preamble. The satellite base station 1010 may improve the reception performance by combining multiple received preambles. In this case, the P obtained by combination may be greater than P_TH.

[0202] On the other hand, two of the terminals 1020A to 1020D may repeatedly transmit preambles to the satellite base station 1010 based on the polarization pattern information received from the satellite base station 1010. Then, the satellite base station 1010 may repeatedly receive the preambles from these two terminals and identify the polarization pattern applied during the preamble transmission. In this case, the satellite base station 1010 may distinguish the transmitting terminals based on the identified polarization pattern, as shown in Table 8.

[0203] [Table 8]

[0204]

[0205]

[0206] On the other hand, three of the terminals 1020A to 1020D may repeatedly transmit preambles to the satellite base station 1010 based on the polarization pattern information received from the satellite base station 1010. Then, the satellite base station 1010 may repeatedly receive the preambles from these three terminals and identify the polarization pattern applied during the preamble transmission. In this case, the satellite base station 1010 may distinguish the transmitting terminals based on the identified polarization pattern, as shown in Table 9.

[0207] [Table 9]

[0208]

[0209]

[0210] On the other hand, the terminals 1020A to 1020D may repeatedly transmit the preamble to the satellite base station 1010 based on the polarization mode information received from the satellite base station 1010. Then, the satellite base station 1010 may repeatedly receive the preamble from the four terminals and identify the polarization mode applied during the transmission of the preamble. In this case, the satellite base station 1010 may distinguish the transmitting terminals based on the identified polarization mode, as shown in Table 10.

[0211] [Table 10]

[0212]

[0213] Therefore, in the proposed scheme, the terminal can repeatedly send the same preamble code to the satellite base station by applying the polarization mode. Accordingly, the satellite base station can receive the same preamble code from any number of terminals using different polarization modes. Thus, the satellite base station can use the polarization mode to distinguish the terminals. In this case, the satellite base station can blindly detect all polarization modes by using the polarization mode applied by the terminal. The satellite base station can determine that the preamble code has been sent using the most likely polarization mode. The above description is an example of the case where four terminals repeatedly send the preamble code four times. The method can be easily extended and applied to different repetition counts and polarization modes.

[0214] The operation of the method according to the exemplary embodiment of the present invention can be implemented as a computer-readable program or code in a computer-readable recording medium. The computer-readable recording medium may include a recording device of all types having data that can be read by a computer system. In addition, the computer-readable recording medium can store and execute programs or codes, which can be distributed in a computer system connected via a network and read by a computer in a distributed manner.

[0215] Computer readable recording media may include hardware devices specifically configured to store and execute program instructions, such as ROM, RAM or flash memory. Program instructions may include not only machine language codes created by a compiler, but also high-level language codes that can be executed by a computer using an interpreter.

[0216] Although some aspects of the present invention have been described in the context of a device, these aspects may indicate the corresponding description according to the method, and a block or device may correspond to the step of the method or the feature of the step. Similarly, the aspects described in the context of the method may be represented as the feature of a corresponding block or project or a corresponding device. Some or all steps of the method may be performed by (or using) a hardware device such as a microprocessor, a programmable computer or an electronic circuit. In some embodiments, one or more of the most important steps of the method may be performed by such a device.

[0217] In some exemplary embodiments, a programmable logic device such as a field programmable gate array can be used to perform some or all of the functions of the methods described herein. In some exemplary embodiments, the field programmable gate array can be operated with a microprocessor to perform one of the methods described herein. Typically, the method is preferably performed by a specific hardware device.

[0218] The description of the present invention is merely exemplary in nature, and therefore variant forms that do not deviate from the essence of the present invention are intended to be within the scope of the present invention. Such variant forms should not be considered as departing from the spirit and scope of the present invention. Therefore, it will be understood by those of ordinary skill in the art that various changes in form and details may be made without departing from the spirit and scope defined by the appended claims.

Claims

1. A method of a user equipment (UE), comprising: receiving configuration information related to a random access channel from a satellite, the configuration information including polarization information indicating a polarization to be used for transmitting a preamble; determining a polarization to use based on the polarization information; selecting a preamble sequence to transmit using the determined polarization; as well as The selected preamble sequence is transmitted to the satellite using the determined polarization.

2. The method according to claim 1, wherein: The polarization information includes information about a polarization type to be used for sending a preamble code, the polarization type is at least one of left-hand circular polarization, right-hand circular polarization or linear polarization, and determining the polarization to be used based on the polarization information includes: determining the polarization to be used among left-hand circular polarization, right-hand circular polarization or linear polarization.

3. The method according to claim 1, wherein: The polarization information includes information about the polarization type and information about the preamble code sequence that can be used for each polarization type, and when determining the polarization to be used based on the polarization information, the UE determines the polarization type to be used, and selecting the preamble code sequence includes: selecting the preamble code sequence to be sent from the preamble code sequences that can be used for the determined polarization type.

4. The method according to claim 1, wherein: The polarization information includes polarization pattern information, determining the polarization to be used based on the polarization information includes: determining an order of polarization types for repeatedly sending preamble codes based on the polarization pattern information, and sending the selected preamble code sequence to the satellite using the determined polarization includes: repeatedly sending the selected preamble code sequence to the satellite based on the determined order of polarization types.

5. The method according to claim 1, further comprising: receiving downlink control information (DCI) scrambled with a random access radio network temporary identifier (RA-RNTI) based on polarization information from a satellite; Generate RA-RNTI based on polarization information; as well as The DCI is decoded using the RA-RNTI.

6. A satellite method comprising: Sending configuration information related to a random access channel to a user equipment (UE), the configuration information including polarization information indicating a polarization to be used for sending a preamble; receiving, from the UE, a preamble sent using polarization based on polarization information; as well as A response signal to the received preamble is sent to the UE.

7. The method according to claim 6, wherein: The polarization information includes information on a polarization type to be used for sending the preamble code, and the polarization type is at least one of left-hand circular polarization, right-hand circular polarization, or linear polarization.

8. The method according to claim 6, wherein: The polarization information includes polarization pattern information, and receiving a preamble code transmitted from the UE using polarization based on the polarization information includes: repeatedly receiving, from the UE, a preamble code repeatedly transmitted based on the polarization pattern information.

9. The method according to claim 8, further comprising: The UE is identified based on the polarization pattern information.

10. The method according to claim 6, further comprising: Generating the RA-RNTI based on the polarization information, wherein sending a response signal to the UE for the received preamble code includes: sending the DCI scrambled with the RA-RNTI; and A response signal is sent to the UE according to the DCI.

11. A user equipment (UE), comprising at least one processor, wherein: The at least one processor causes the UE to execute: receiving configuration information related to a random access channel from a satellite, the configuration information including polarization information indicating a polarization to be used for transmitting a preamble; determining a polarization to use based on the polarization information; selecting a preamble sequence to transmit using the determined polarization; as well as The selected preamble sequence is transmitted to the satellite using the determined polarization.

12. The UE according to claim 11, wherein: The polarization information includes information about a polarization type to be used for sending a preamble code, the polarization type being at least one of left-hand circular polarization, right-hand circular polarization, or linear polarization, and when determining the polarization to be used based on the polarization information, the at least one processor further causes the UE to execute: determining the polarization to be used among left-hand circular polarization, right-hand circular polarization, or linear polarization.

13. The UE according to claim 11, wherein: The polarization information includes polarization pattern information; when determining the polarization to be used based on the polarization information, the at least one processor further causes the UE to execute: determining an order of polarization types for repeatedly sending the preamble code based on the polarization pattern information; when sending the selected preamble code sequence to the satellite using the determined polarization, the at least one processor further causes the UE to execute: repeatedly sending the selected preamble code sequence to the satellite based on the determined order of polarization types.

14. The UE according to claim 11, wherein: The at least one processor further causes the UE to execute: receiving downlink control information (DCI) scrambled with a random access radio network temporary identifier (RA-RNTI) based on polarization information from a satellite; Generate RA-RNTI based on polarization information; as well as The DCI is decoded using the RA-RNTI.

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