Terminal and communication method

Abstract

To appropriately perform initial access in a Non-Terrestrial Network (NTN).SOLUTION: A terminal comprises: a control unit that decides to use a physical random access channel (PRACH) configuration parameter that is different from when a Global Navigation Satellite System (GNSS) information is used or when in a Terrestrial Network (TN) environment, if the GNSS information is not used in a Non-Terrestrial Network (NTN) environment; and a communication unit that transmits a PRACH by using the PRACH configuration parameter.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a terminal and a communication method in a wireless communication system. [Background technology]

[0002] For NR (New Radio) (also known as "5G"), the successor system to LTE (Long Term Evolution), technologies that satisfy requirements such as a large-capacity system, high-speed data transmission speed, low latency, simultaneous connection of a large number of terminals, low cost, and low power consumption are being considered (for example, Non-Patent Document 1).

[0003] Currently, non-terrestrial networks (NTNs) are being considered. NTNs use non-terrestrial networks such as satellites to provide services to areas that cannot be covered by terrestrial 5G networks, mainly due to cost considerations (e.g., Non-Patent Documents 2 and 3). [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] 3GPP TS 38.300 V18.4.0 (2024-12) [Non-patent document 2] 3GPP TR 38.821 V16.2.0 (2023-03) [Non-patent document 3] Konishi et al., "A Study on Downlink Spectrum Sharing in HAPS Mobile Communication Systems," Institute of Electronics, Information and Communication Engineers General Conference, B-17-1, 2020 [Non-patent document 4] 3GPP TS 38.331 V18.4.0 (2024-12) [Non-patent document 5] 3GPP TS 38.211 V18.5.0 (2024-12) Summary of the Invention [Problem to be solved by the invention]

[0005] Previously, NTN required the Global Navigation Satellite System (GNSS) as a synchronization source. However, frequent acquisition of GNSS information increases power consumption in the terminal, and GNSS signals may not be available in some environments. This can result in large timing advance errors and transmission collisions between different UEs. Therefore, if GNSS signals are not available, initial access may not function effectively.

[0006] The present invention has been made in view of the above points, and has as its object to properly execute initial access in an NTN (Non-Terrestrial Network). [Means for solving the problem]

[0007] According to the disclosed technology, there is provided a terminal having a control unit that determines to use PRACH (Physical random access channel) setting parameters that are different from those used when GNSS (Global Navigation Satellite System) information is not used or when TN (Terrestrial Network) information is used in an NTN (Non-Terrestrial Network) environment, and a communication unit that transmits PRACH using the PRACH setting parameters. [Effects of the Invention]

[0008] According to the disclosed technology, initial access can be properly performed in an NTN (Non-Terrestrial Network). [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing an example of NTN (1). [Figure 2]FIG. 10 is a diagram showing an example (2) of NTN. [Figure 3] This is a diagram showing an example (3) of NTN. [Figure 4] This is a diagram showing an example (4) of NTN. [Figure 5] 10 is a flowchart illustrating an example of an initial access operation according to an embodiment of the present invention. [Figure 6] 2 is a diagram illustrating an example of a functional configuration of a base station 10 according to an embodiment of the present invention. [Figure 7] FIG. 2 is a diagram illustrating an example of a functional configuration of a terminal 20 according to the embodiment of the present invention. [Figure 8] 2 is a diagram illustrating an example of a hardware configuration of a base station 10 or a terminal 20 according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the embodiment described below is an example, and the embodiment to which the present invention is applied is not limited to the following embodiment.

[0011] In the operation of the wireless communication system according to the embodiment of the present invention, existing technologies are used as appropriate. However, the existing technologies are, for example, but not limited to, the existing LTE. Furthermore, the term "LTE" used in this specification has a broad meaning including LTE-Advanced and systems subsequent to LTE-Advanced (e.g., NR) unless otherwise specified.

[0012] Furthermore, in the embodiments of the present invention described below, terms used in existing LTE, such as SS (Synchronization signal), PSS (Primary SS), SSS (Secondary SS), PBCH (Physical broadcast channel), PRACH (Physical random access channel), PDCCH (Physical Downlink Control Channel), PDSCH (Physical Downlink Shared Channel), PUCCH (Physical Uplink Control Channel), and PUSCH (Physical Uplink Shared Channel), are used. This is for convenience of description, and similar signals, functions, etc. may be referred to by other names. Furthermore, the above-mentioned terms in NR correspond to NR-SS, NR-PSS, NR-SSS, NR-PBCH, NR-PRACH, NR-PDCCH, NR-PDSCH, NR-PUCCH, NR-PUSCH, etc. However, even signals used in NR are not necessarily designated as "NR-."

[0013] Furthermore, in the embodiments of the present invention, the duplex method may be a TDD (Time Division Duplex) method, an FDD (Frequency Division Duplex) method, or other methods (for example, Flexible Duplex, etc.).

[0014] Furthermore, in the embodiments of the present invention, when radio parameters and the like are "configured," it may mean that predetermined values ​​are pre-configured, or that radio parameters notified from the base station 10 or the terminal 20 are set.

[0015] Figure 1 shows an example of an NTN (1). An NTN (Non-Terrestrial Network) uses non-terrestrial devices such as satellites to provide services to areas that cannot be covered by terrestrial 5G networks, primarily due to cost. NTN also enables the provision of more reliable services. For example, it is expected to be applied to IoT (Internet of Things), ships, buses, trains, and critical communications. NTN also has scalability through efficient multicast or broadcast.

[0016] As an example of an NTN, as shown in FIG. 1, a satellite 10A can retransmit signals transmitted from a terrestrial base station 10B to provide service to areas where no terrestrial base stations are located, such as mountainous regions.

[0017] The terrestrial 5G network may have the following configuration. The terrestrial 5G network includes one or more base stations 10 and terminals 20. The base station 10 is a communication device that provides one or more cells and performs wireless communication with the terminals 20. The physical resources of a wireless signal are defined in the time domain and the frequency domain, and the time domain may be defined by the number of OFDM symbols, and the frequency domain may be defined by the number of subcarriers or the number of resource blocks. The base station 10 transmits a synchronization signal and system information to the terminals 20. The synchronization signal is, for example, NR-PSS and NR-SSS. The system information is transmitted, for example, on NR-PBCH, and is also called broadcast information.

[0018] The base station 10 transmits control signals or data to the terminal 20 via DL (Downlink) and receives control signals or data from the terminal 20 via UL (Uplink). Both the base station 10 and the terminal 20 are capable of transmitting and receiving signals by performing beamforming. Furthermore, both the base station 10 and the terminal 20 are capable of applying MIMO (Multiple Input Multiple Output) communication to DL or UL. Furthermore, both the base station 10 and the terminal 20 may communicate via an SCell (Secondary Cell) and a PCell (Primary Cell) using CA (Carrier Aggregation).

[0019] The terminal 20 is a communication device equipped with a wireless communication function, such as a smartphone, a mobile phone, a tablet, a wearable terminal, an M2M (Machine-to-Machine) communication module, etc. The terminal 20 receives control signals or data from the base station 10 via DL and transmits control signals or data to the base station 10 via UL, thereby utilizing various communication services provided by the wireless communication system.

[0020] Figure 2 shows an example of an NTN (2). The area of ​​each cell or beam in an NTN is much larger than that of a terrestrial network (TN). Figure 2 shows an example of an NTN configured with retransmission by satellite. The connection between the satellite 10A and the NTN gateway 10B is called the feeder link, and the connection between the satellite 10A and the UE 20 is called the service link.

[0021] As shown in Figure 2, the difference in delay between UE 20A on the near side and UE 20B on the far side is, for example, 10.3 ms in the case of GEO (Geosynchronous orbit) and 3.2 ms in the case of LEO (Low Earth orbit). Also, the beam size in NTN is, for example, 3500 km in the case of GEO and 1000 km in the case of LEO.

[0022] FIG. 3 is a diagram showing an example (3) of an NTN. As shown in FIG. 3, an NTN is realized by a satellite in space or a flying object in the air. For example, a GEO satellite may be a satellite located at an altitude of 35,786 km and having a geostationary orbit. For example, a LEO satellite may be a satellite located at an altitude of 500-2000 km and orbiting every 88-127 minutes. For example, a HAPS (High Altitude Platform Station) may be a flying object located at an altitude of 8-50 km and performing circular flight.

[0023] As shown in Figure 3, GEO satellites, LEO satellites, and HAPS aircraft may be connected to ground stations (gNBs) via gateways. The service areas may be larger in the order of HAPS, LEO, and GEO.

[0024] For example, NTN can extend the coverage of a 5G network to unserved or served areas. Furthermore, NTN can improve the continuity, availability, and reliability of services on ships, buses, trains, or other critical communications. The NTN may be signaled by transmitting dedicated parameters to the terminal 20, and the dedicated parameters may be parameters related to determining a timing advance (TA) based on information related to a satellite or an aircraft.

[0025] FIG. 4 is a diagram showing an example (4) of an NTN. FIG. 4 shows an example of an NTN network architecture assumed in the case of transparent payload. As shown in FIG. 4, a CN (Core Network) 10D, a gNB 10C, and a gateway 10B are connected. The gateway 10B is connected to a satellite 10A via a feeder link. The satellite 10A is connected to a terminal 20A or a VSAT (Very Small Aperture Terminal) 20B via a service link. An NR Uu is established between the gNB 10C and the terminal 20A or the VSAT 20B.

[0026] NTN's network architecture may be FDD or TDD. Terrestrial cells may be fixed or mobile. Terminal 20 may have the capability to support GNSS (Global Navigation Satellite System). For example, a power class 3 handheld device may be assumed in FR1. A VSAT device may be assumed at least in FR2.

[0027] NTN's network architecture may also assume regenerative payloads. For example, gNB functionality may be mounted on a satellite or air vehicle. Alternatively, a gNB-DU may be mounted on a satellite or air vehicle, and a gNB-CU may be deployed as a ground station.

[0028] Traditionally, GNSS capability has been assumed for UEs, meaning that the UE can acquire GNSS information with, for example, an accuracy of 50 m. In NTN, GNSS information is required for UEs for uplink timing and frequency compensation. 5G satellite access, on the other hand, requires authorized UEs to be able to provide service independently of GNSS capability.

[0029] Regarding the acquisition of UE location information, the following events are assumed: 1) Frequent acquisition of GNSS information increases the power consumption of the UE. 2) For a variety of reasons, GNSS signals may be temporarily unavailable or lost.

[0030] Due to the above-mentioned events, GNSS resilience or mitigation is being considered. Based on the GNSS resilience or mitigation, enhancements to the initial access procedure are required. Note that GNSS resilience or mitigation may also mean the case where GNSS information is at least temporarily unavailable.

[0031] As mentioned above, GNSS on the UE side is expected to be temporarily unavailable, and even if it is available, it is expected to be degraded to the extent that the accuracy of the GNSS positioning is reduced. These events may occur more frequently, which may reduce the robustness of NTN services.

[0032] For example, GNSS jamming can result in denial of service. GNSS spoofing and other influences beyond the control of the satellite network operator, such as suboptimal satellite constellations, regional blockages, solar wind activity, and increased GNSS measurement periods to reduce UE power, can lead to inaccurate position calculations and results on the UE side, resulting in an out-of-synchronization state. When NTN access is available but the GNSS signal is very weak, the UE may find itself at a disadvantage due to the difference in link budget margins between the two systems.

[0033] GNSS information for GNSS-capable UEs may be temporarily unavailable, may be available but with reduced GNSS position accuracy, or may be available but with an increased GNSS measurement period for power saving purposes. Therefore, operations must be performed to anticipate situations where GNSS may be temporarily unavailable.

[0034] As a PRACH configuration, a random access channel is defined in the existing specifications (see Non-Patent Document 4). The PHY layer model for RACH transmission is characterized by a PRACH preamble format that includes a cyclic prefix (CP), a preamble, and a guard time. The following shows an example of a PRACH configuration:

[0035] RACH-ConfigCommon ::= SEQUENCE { rach-ConfigGeneric RACH-ConfigGeneric, totalNumberOfRA-Preambles INTEGER (1..63) OPTIONAL, -- Need S ssb-perRACH-OccasionAndCB-PreamblesPerSSB CHOICE { oneEighth ENUMERATED {n4,n8,n12,n16,n20,n24,n28,n32,n36,n40,n44,n48,n52,n56,n60,n64}, oneFourth ENUMERATED {n4,n8,n12,n16,n20,n24,n28,n32,n36,n40,n44,n48,n52,n56,n60,n64}, oneHalf ENUMERATED {n4,n8,n12,n16,n20,n24,n28,n32,n36,n40,n44,n48,n52,n56,n60,n64}, one ENUMERATED {n4,n8,n12,n16,n20,n24,n28,n32,n36,n40,n44,n48,n52,n56,n60,n64}, two ENUMERATED {n4,n8,n12,n16,n20,n24,n28,n32}, four INTEGER (1..16), eight INTEGER (1..8), sixteen INTEGER (1..4) } OPTIONAL, -- Need M groupBconfigured SEQUENCE { ra-Msg3SizeGroupA ENUMERATED {b56, b144, b208, b256, b282, b480, b640, b800, b1000, b72, spare6, spare5,spare4, spare3, spare2, spare1}, messagePowerOffsetGroupB ENUMERATED { minusinfinity, dB0, dB5, dB8, dB10, dB12, dB15, dB18}, numberOfRA-PreamblesGroupA INTEGER (1..64) } OPTIONAL, -- Need R ra-ContentionResolutionTimer ENUMERATED { sf8, sf16, sf24, sf32, sf40, sf48, sf56, sf64}, rsrp-ThresholdSSB RSRP-Range OPTIONAL, -- Need R rsrp-ThresholdSSB-SUL RSRP-Range OPTIONAL, -- Cond SUL prach-RootSequenceIndex CHOICE { l839 INTEGER (0..837), l139 INTEGER (0..137) }, msg1-SubcarrierSpacing SubcarrierSpacing OPTIONAL, -- Cond L139 restrictedSetConfig ENUMERATED {unrestrictedSet, restrictedSetTypeA, restrictedSetTypeB}, msg3-transformPrecoder ENUMERATED {enabled} OPTIONAL, -- Need R ..., [[ ra-PrioritizationForAccessIdentity-r16 SEQUENCE { ra-Prioritization-r16 RA-Prioritization, ra-PrioritizationForAI-r16 BIT STRING (SIZE (2)) } OPTIONAL, -- Cond InitialBWP-Only prach-RootSequenceIndex-r16 CHOICE { l571 INTEGER (0..569), l1151 INTEGER (0..1149) } OPTIONAL -- Need R ]], [[ ra-PrioritizationForSlicing-r17 OPTIONAL, -- Cond InitialBWP-Only featureCombinationPreamblesList-r17 SEQUENCE (SIZE(1..maxFeatureCombPreamblesPerRACHResource-r17)) OF FeatureCombinationPreambles-r17 OPTIONAL -- Cond AdditionalRACH ]] }

[0036] Prior art assumes UEs with GNSS capabilities. However, in NTN environments, GNSS information at the UE may be (e.g., temporarily) unavailable, lost, and / or degraded, which may lead to large TA errors, TX collisions between different UEs, and BSs may fail to receive signals from the UEs.

[0037] In such cases, the initial access procedure based on GNSS information may not work well, and initial access without GNSS information needs to be defined / used. Regarding the PRACH format, the legacy PRACH preamble format may not be suitable due to inaccurate TA compensation, and PRACH transmission may fail because there may be a larger TA error due to GNSS issues. Regarding the PRACH resource, the required PRACH resource may be different for a UE with GNSS and a UE without GNSS. The same resource configuration is not efficient.

[0038] An embodiment of the present invention may cover both of the following cases: 1) The UE does not use GNSS information to access the cellular network; and 2) The UE uses GNSS information to access the cellular network when it is available or accurate, but the GNSS information at the UE is temporarily unavailable, lost, and / or degraded. Note that an embodiment of the present invention may be applied to 6G-NTN communications.

[0039] 5 is a flowchart illustrating an example of an initial access operation in an embodiment of the present invention. In step S101, the UE performs initial access when GNSS is unavailable. The procedure for this initial access will be described later. For example, the UE may perform PRACH transmission using PRACH configuration parameters for when GNSS is unavailable that are different from PRACH configuration parameters for when GNSS is available. Note that when GNSS is unavailable, this may be replaced with "when GNSS information is not used," and when GNSS is available, this may be replaced with "when GNSS information is used or in a TN environment," and this is the same in the embodiment of the present invention.

[0040] In NTN, a specific PRACH resource may be determined and used when GNSS information at the UE is (e.g., temporarily) unavailable, lost, or degraded for initial access, or when the UE attempts initial access without using GNSS information (these cases are referred to in embodiments of the present invention as "in the absence of GNSS," "in the absence of GNSS information," etc.).

[0041] Option 1) Use a PRACH preamble format for when GNSS is not present. For example, a PRACH preamble format having a larger CP than a format that can be used in a TN or NTN with GNSS information (which may be called "format X") may be used as the PRACH preamble format. For example, a PRACH preamble format having a larger sequence than format X may be used as the PRACH preamble format. Table 1 shows examples of PRACH preamble formats.

[0042] [Table 1]

[0043] As shown in Table 1, the conventional L RA A larger sequence may be used. A larger sequence may mean a larger sequence length. Also, as shown in Table 1, the conventional cyclic prefix length N CP greater than N CP may be used.

[0044] In addition, L RA denotes the sequence length of the random access preamble. RA denotes the subcarrier spacing of the initial UL-BWP during initial access. N U N denotes the length of the sequence to which the repetition is applied. CP indicates the length of the cyclic prefix. It may be supported for a restricted set (unrestricted, restricted type A, restricted type B) or the types of restricted set supported for different preamble formats may be signaled.

[0045] The following parameters of the PRACH preamble format (especially the longer sequences) for the case without GNSS may apply:

[0046] For example, from logical index i, L of format X RA A mapping to a sequence number u indicating a preamble format different from the value may be performed.

[0047] For example, the value of format X is different from L RA N for preamble formats with CS may be applied.

[0048] For example, the Δf RA Different combinations of Δf and Δf and corresponding values ​​of k may be applied, where Δf denotes the subcarrier spacing of the active UL-BWP. k is determined by referring to Table 6.3.3.2-1 in Non-Patent Document 5. RA and Δf.

[0049] The PRACH preamble format without GNSS may be predefined.

[0050] For example, a PRACH configuration index different from that for format X may specify a different row in "Table 6.3.3.2-2: Random Access Configuration for FR1 and Paired Spectrum / Supplementary Uplink" in Non-Patent Document 5, thereby specifying the PRACH preamble format in the absence of GNSS.

[0051] For example, the PRACH preamble format in the absence of GNSS may be specified by a different table specific to the absence of GNSS, having the same information types as in Table 6.3.3.2-2 in Non-Patent Document 5.

[0052] Option 2) A Guard period (GP) may be configured and used for PRACH transmissions with format X.

[0053] For example, GP may be a common value for all PRACH formats or may be associated with each PRACH format. For example, GP may be a common value for all PRACH resources or may be associated with each PRACH resource.

[0054] For example, the GP may be configured together with the PRACH configuration via system information (e.g., SIB1) or configured separately from the PRACH configuration, for example, via a SIB defined for NTN (e.g., SIB19 in 5G-NR).

[0055] Different configurations of PRACH resources are provided for UEs with GNSS and UEs without GNSS, and each UE may decide which configuration to use based on whether GNSS information is used or not, where UEs without GNSS refer to UEs without GNSS information, and UEs with GNSS refer to UEs that use GNSS information for NTN access.

[0056] For example, separate PRACH resources may be allocated for UEs with GNSS and UEs without GNSS using different time and / or frequency locations.

[0057] For the separated and distinct PRACH resources or PRACH configurations, the following parameters may be different:

[0058] A PRACH configuration index, including for example a preamble format, RO (RACH Occasion) periodicity and / or offset. For example, a format with a larger CP may be configured for a UE without GNSS compared to the CP of the format for a UE with GNSS. For example, the PRACH root sequence index. For example, the number of SSBs per PRACH opportunity, e.g. set to a smaller value for UEs without GNSS compared to UEs with GNSS. For example, the number of CB (Contention based) preambles per SSB. For example, the total number of preambles used for random access. For example, a contention resolution timer. For example, msg1-FDM. For example, msg1-FreuqencyStart.

[0059] The PRACH preamble sequences are derived from a root sequence, which defines successive logical indices until all 64 sequences are found. The sequence numbers are derived from the logical root sequence index by referring to tables 6.3.3.3.1-3 to 6.3.3.1-4B in Non-Patent Document 5.

[0060] Separate PRACH configurations may be configured by SIB1, or PRACH configurations for UEs with GNSS may be configured via SIB#A (e.g., SIB1) and PRACH configurations for UEs without GNSS may be configured via SIB#B (e.g., SIB defined for NTN, SIB19).

[0061] For example, separate PRACH opportunities (time-frequency resources) can be configured for UEs with GNSS and UEs without GNSS. For example, a PRACH mask index can be configured to indicate the allowed PRACH opportunities for UEs without GNSS or the allowed PRACH opportunities for UEs with GNSS. Note that the PRACH mask index indicates the RACH opportunity associated with the SS / PBCH indicated by the SS / PBCH index for PRACH transmission.

[0062] For example, separate PRACH time domain resources can be configured for UEs with GNSS and UEs without GNSS. For example, the allowed time resources in PRACH slots for UEs without GNSS or the allowed time resources in PRACH slots for UEs with GNSS may be signaled. For example, the allowed PRACH slots for UEs without GNSS may be signaled, or the PRACH slots or UEs with GNSS may be allowed.

[0063] For example, PRACH configuration parameter #A and PRACH configuration parameter #B may be provided. PRACH configuration parameter #A may be commonly used by UEs with GNSS and UEs without GNSS. PRACH configuration parameter #B may be used only by UEs without GNSS.

[0064] A UE with GNSS may determine the PRACH resource based on PRACH configuration parameter #A, and a UE without GNSS may determine the PRACH resource based on both PRACH configuration parameter #A and PRACH configuration parameter #B.

[0065] Each of the PRACH configuration parameter #A and the PRACH configuration parameter #B may be broadcast via system information (e.g., SIB1, an SIB defined for NTN (e.g., SIB19 in 5G-NR)). The PRACH configuration parameter #B may be an absolute value or a relative value to the PRACH configuration parameter #A.

[0066] For example, PRACH configuration parameter #A may be provided, and then PRACH configuration parameter #B may be determined based on a predetermined relationship.

[0067] PRACH configuration parameter #A is used by UEs with GNSS. PRACH configuration parameter #B is only used by UEs without GNSS.

[0068] The predetermined relationship between each parameter of the PRACH configuration may be as follows:

[0069] PRACH setting index: When "0" is set for PRACH setting parameter #A, "28" is applied for PRACH setting parameter #B, when "1" is set for PRACH setting parameter #A, "29" is applied for PRACH setting parameter #B, etc. Number of SSBs per PRACH opportunity: If "16" is set for PRACH setting parameter #A, then "8" is applied for PRACH setting parameter #B; if "8" is set for PRACH setting parameter #A, then "4" is applied for PRACH setting parameter #B, etc.

[0070] That is, based on the PRACH configuration parameter #A, a predetermined value may be added to the value or divided by the value, etc., to determine the PRACH configuration parameter B. Note that similar rules can be adopted for the other parameters to be separated as mentioned above.

[0071] It may also specify how the UE decides to act:

[0072] · Whether to use PRACH format or Format X in the absence of GNSS. - Whether to apply the set guard period. ·Whether to use PRACH resources for UEs with GNSS or PRACH resources for UEs without GNSS.

[0073] The UE may decide to apply the above-mentioned actions as follows:

[0074] For example, the decision to apply the above-described actions may be based on whether the UE has GNSS capability.

[0075] For example, it may be determined to apply the above-mentioned operations based on thresholds for TA error, frequency error, or GNSS accuracy predefined or configured by system information (e.g., SIB1, SIBs defined for NTN (e.g., SIB19 in 5G-NR)). It may also be determined to apply the above-mentioned operations when at least one or more of the TA error, frequency error, or GNSS accuracy exceed a threshold. A PRACH format for no GNSS may be used, or a configured guard period may be applied, or a PRACH resource for UEs without GNSS may be used. For example, when the GNSS accuracy exceeds a threshold but the TA error and frequency offset error do not exceed a threshold, format X may be used, or the configured guard period may not be applied, or a PRACH resource for UEs with GNSS may be used.

[0076] For example, a specific timer may be defined and / or configured by the system information (e.g., SIB1, a SIB defined for NTN (e.g., SIB19 in 5G-NR)), and if the timer expires, the PRACH format for the case without GNSS may be used, or the configured guard period may be applied, or the PRACH resource for the UE without GNSS may be used.

[0077] For example, the threshold and timer combinations may be:

[0078] For example, if the TA error, frequency error and / or GNSS accuracy exceeds a threshold during the timer duration, the PRACH format without GNSS may be used, or the configured guard period may be applied, or the PRACH resource for UEs without GNSS may be used. If the TA error, frequency error and / or GNSS accuracy exceeds a threshold but not within the timer duration, format X may be used, or the configured guard period may not be applied, or the PRACH resource for UEs with GNSS may be used.

[0079] The UE may report the following capabilities:

[0080] Ability to perform each of the above mentioned actions. The ability of each option in the action, or the ability of a combination of options. - Ability to perform each option or combination of options in a movement.

[0081] The UE may report the capabilities per frequency, for example, per UE, per FR1, FR2, FR2-1, FR2-2, per SCS, per band or subband, per BC, per FC, or per FSPC.

[0082] The UE can report the above capabilities on a per-cell basis, per-UE, per-cell basis, or per TDD and FDD basis.

[0083] Throughout the above operations, whether and which operations are applied and / or which options or alternatives are used may be determined by the following. - Set by upper layer parameters. Determined by relevant higher layer parameters. Notified by MAC-CE or DCI. Determined based on UE capabilities. - As described in the above operation. · Based on the conditions stated in the operation above. Determined by higher layer parameters / MAC-CE / DCI configuration and reported UE capabilities (combination of the above decisions).

[0084] Throughout the operation, multiple options and alternatives may be combined into a single option or alternative.

[0085] Throughout operation, the UE may assume that some actions, action options, or action alternatives may only be applied when the UE reports support for a certain feature or model.

[0086] The UE may receive information from the NW as the following types (the NW can be referred to as gNB throughout the operation):

[0087] Information via higher layer signaling (e.g., RRC messages / LPP messages) MAC CE MAC CE with new LCID in subheader Extending an existing MAC CE (e.g., introducing a new octet). DCI -DCI Field: Existing DCI field or newly introduced DCI field RNTI: DCI with CRC scrambled by an existing RNTI or a newly introduced RNTI. -DCI format: existing DCI format or newly introduced DCI format Combination of the above information

[0088] The UE can receive information from the NW in the following periodic types: Option 1: Periodic Option 2: Semi-persistent (triggered by UE or gNB notification) Option 3: Aperiodic (triggered by UE or gNB notification)

[0089] The UE can report information to the NW as the following types (the NW can be referred to as gNB throughout the proposal): Information via higher layer signaling (e.g., RRC messages / LPP messages) MAC CE MAC CE with new LCID in subheader Extending an existing MAC CE (e.g., introducing a new octet). UCI UCI on PUCCH or PUSCH Combination of the above information

[0090] In addition, the UE can report information to the NW in the following periodic types: Option 1: Periodic Option 2: Semi-persistent (triggered by UE or gNB notification) Option 3: Aperiodic (triggered by UE or gNB notification)

[0091] By the above-described operation, even if GNSS information is not available in the NTN environment, initial access can be performed by specifying the resources and appropriate procedures required for initial access.

[0092] That is, initial access can be properly performed in an NTN (Non-Terrestrial Network).

[0093] (Device configuration) Next, a description will be given of examples of functional configurations of the base station 10, network node 30, and terminal 20 that perform the processes and operations described above. The base station 10, network node 30, and terminal 20 include functions for performing the above-described embodiments. However, the base station 10, network node 30, and terminal 20 may each include only a part of the functions of the embodiments.

[0094] <Base Station 10 and Network Node 30> FIG. 6 is a diagram showing an example of the functional configuration of the base station 10 and the network node 30. As shown in FIG. 6, the base station 10 has a transmitting unit 110, a receiving unit 120, a setting unit 130, and a control unit 140. The functional configuration shown in FIG. 6 is merely an example. As long as the operations according to the embodiment of the present invention can be performed, the names of the functional divisions and functional units may be any. Note that the network node 30 may have the same functional configuration as the base station 10. Furthermore, a network node 30 having multiple different functions in the system architecture may be composed of multiple network nodes 30 separated by function.

[0095] The transmitter 110 includes a function of generating a signal to be transmitted to the terminal 20 or another network node 30, and transmitting the signal by wire or wirelessly. The receiver 120 includes a function of receiving various signals transmitted from the terminal 20 or another network node 30, and acquiring, for example, information of a higher layer from the received signal. A communication unit including the transmitter 110 and the receiver 120 may be configured.

[0096] The transmitter 110 includes a function of generating a signal to be transmitted to the terminal 20 and transmitting the signal wirelessly. The transmitter 110 also transmits setting information, instructions, notifications, etc. related to a low-power wake-up signal to the terminal 20. The transmitter 110 also transmits notifications related to switching of monitoring operations to the terminal. The receiver 120 includes a function of receiving various signals transmitted from the terminal 20 and acquiring, for example, information of higher layers from the received signals. The transmitter 110 also has a function of transmitting PSS, SSS, PBCH, DL / UL control signals, etc. to the terminal 20. The receiver 120 also receives inter-network node messages from other network nodes.

[0097] The setting unit 130 stores preset setting information and various setting information to be transmitted to the terminal 20. The content of the setting information is, for example, information related to the operations described in the embodiments.

[0098] The control unit 140 controls settings, instructions, and notifications related to the operations described in the embodiments. The function unit related to signal transmission in the control unit 140 may be included in the transmitting unit 110, and the function unit related to signal reception in the control unit 140 may be included in the receiving unit 120.

[0099] <Terminal 20> Fig. 7 is a diagram showing an example of the functional configuration of terminal 20 in an embodiment of the present invention. As shown in Fig. 7, terminal 20 has a transmitting unit 210, a receiving unit 220, a setting unit 230, and a control unit 240. The functional configuration shown in Fig. 7 is merely an example. As long as the operations related to the embodiment of the present invention can be performed, the names of the functional divisions and functional units may be any. Transmitting unit 210 and receiving unit 220 may be collectively referred to as a communication unit.

[0100] The transmitter 210 creates a transmission signal from transmission data and transmits the transmission signal wirelessly. The transmitter 210 also transmits capability information related to the low-power wake-up signal to the base station 10. The receiver 220 receives various signals wirelessly and acquires higher layer signals from the received physical layer signals. The receiver 220 also has a function of receiving PSS, SSS, PBCH, DL / UL / SL control signals, etc. transmitted from the base station 10. The receiver 220 also receives paging notification information and configuration information, instructions, and notifications related to the low-power wake-up signal from the base station 10. For example, the receiver 220 receives a low-power wake-up signal from the base station 10. The setting unit 230 stores various configuration information received by the receiver 220 from the base station 10. The setting unit 230 also stores pre-configured configuration information. The content of the configuration information is, for example, information related to the operations described in the embodiments.

[0101] As described in the embodiments, the control unit 240 controls settings, instructions, and notifications related to the operations described in the embodiments. A functional unit related to signal transmission in the control unit 240 may be included in the transmitting unit 210, and a functional unit related to signal reception in the control unit 240 may be included in the receiving unit 220.

[0102] (Hardware configuration) The block diagrams (FIGS. 6 and 7) used to explain the above embodiments show functional blocks. These functional blocks (components) are realized by hardware, software, or a combination of these. Furthermore, the method of realizing each functional block is not particularly limited. That is, each functional block may be realized by using one device that is physically or logically coupled, or may be realized by using two or more physically or logically separated devices that are connected directly or indirectly (for example, using wires, wirelessly, etc.) and these multiple devices. The functional block may be realized by combining the one device or the multiple devices with software.

[0103] For example, a base station, a terminal, a network node, etc. according to an embodiment of the present disclosure may function as a computer that performs processing of the wireless communication method of the present disclosure. Fig. 8 is a diagram illustrating an example of the hardware configuration of a base station and a terminal according to an embodiment of the present disclosure. The above-described base station 10 and terminal 20 may be physically configured as a computer device including a processor 1001, a memory 1002, a storage 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, etc.

[0104] In the present disclosure, the term "apparatus" may be interchangeable with any two terms selected from a set of terms such as circuit, device, unit, module, chip, means, etc. The hardware configurations of the base station 10 and the terminal 20 may be configured to include one or more of the devices shown in the drawings, or may be configured to exclude some of the devices.

[0105] Each function in the base station 10 and the terminal 20 is realized by loading predetermined software (programs) onto hardware such as the processor 1001, memory 1002, etc., so that the processor 1001 performs calculations, controls communication by the communication device 1004, and controls the reading, writing, or both reading and writing of data in the memory 1002 and storage 1003.

[0106] The processor 1001, for example, runs an operating system to control the entire computer. The processor 1001 may be configured as a central processing unit (CPU) including an interface with peripheral devices, a control device, an arithmetic unit, a register, etc. For example, a baseband signal processing unit, a call processing unit, etc. may be realized by the processor 1001. Although only one processor 1001 is shown in the figure, there may be multiple processors.

[0107] The processor 1001 also reads programs (program codes), software modules, data, etc. from the storage 1003, the communication device 1004, or both the storage 1003 and the communication device 1004 into the memory 1002, and executes various processes in accordance with the programs. The programs used are those that cause a computer to execute at least some of the operations described in the above-described embodiments. For example, the control unit 401 of the terminal 20 may be implemented by a control program stored in the memory 1002 and running on the processor 1001, and similar implementations may be made for other functional blocks. While the above-described various processes have been described as being executed by a single processor 1001, they may also be executed simultaneously or sequentially by two or more processors 1001. The processor 1001 may be implemented by one or more chips. The programs may be transmitted from a network via a telecommunications line, or may be provided to the computer via the communication device 1004, for example.

[0108] The present disclosure also provides a computer program product including a computer program, which may implement the steps of the methods described in the above embodiments when the computer program is executed by a computer (e.g., the processor 1001).

[0109] The memory 1002 is a computer-readable recording medium and may be configured, for example, as a read-only memory (ROM), an erasable programmable ROM (EPROM), an electrically erasable programmable ROM (EEPROM), a random access memory (RAM), or a combination of at least two of these. The memory 1002 may also be called a register, a cache, a main memory (primary storage device), or the like. The memory 1002 can store executable programs (program codes), software modules, and the like for implementing a wireless communication method according to an embodiment of the present disclosure.

[0110] Storage 1003 is a computer-readable recording medium, and may be, for example, an optical disk such as a CD-ROM (Compact Disc ROM), a hard disk drive, a flexible disk, a magneto-optical disk (e.g., a compact disk, a digital versatile disk, a Blu-ray disc), a smart card, a flash memory (e.g., a card, a stick, a key drive), a floppy disk, a magnetic strip, or a combination of at least two of these. Storage 1003 may also be referred to as an auxiliary storage device. The above-mentioned storage medium may be, for example, memory 1002, storage 1003, or a database, server, or other appropriate medium including both memory 1002 and storage 1003.

[0111] The communication device 1004 is hardware (transmitting / receiving device) for communicating between computers via a wired network, a wireless network, or both wired and wireless networks, and is also referred to as, for example, a network device, a network controller, a network card, or a communication module. The communication device 1004 may be configured to include a high-frequency switch, a duplexer, a filter, a frequency synthesizer, or a combination of at least two of these. For example, a transmitting / receiving antenna, an amplifier unit, a transmitting / receiving unit, or a transmission path interface may be realized by the communication device 1004. The transmitting / receiving unit may be implemented as a transmitting unit and a receiving unit that are physically or logically separated.

[0112] The input device 1005 is an input device that accepts input from the outside (for example, a keyboard, a mouse, a microphone, a switch, a button, a sensor, or a combination of at least two of these). The output device 1006 is an output device that outputs to the outside (for example, a display, a speaker, an LED lamp, or a combination of at least two of these). The input device 1005 and the output device 1006 may be integrated into one device (for example, a touch panel).

[0113] Furthermore, each device, such as the processor 1001 and the memory 1002, is connected by a bus 1007 for communicating information. The bus 1007 may be configured using a single bus, or may be configured using different buses between each device.

[0114] Furthermore, base station 10 and terminal 20 may be configured to include hardware such as a microprocessor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a programmable logic device (PLD), a field programmable gate array (FPGA), a graphics processing unit (GPU), a neural processing unit (NPU), or a combination of at least two of these, and some or all of the functional blocks may be realized by the hardware. For example, processor 1001 may be implemented using at least one of these pieces of hardware.

[0115] <Configuration of this embodiment> (Section 1) a control unit that determines whether to use a PRACH (Physical random access channel) setting parameter different from that used in a TN (Terrestrial Network) environment when GNSS (Global Navigation Satellite System) information is not used, or when GNSS information is used, in an NTN (Non-Terrestrial Network) environment; a communication unit that transmits a PRACH using the PRACH configuration parameters. (Section 2) The terminal according to claim 1, wherein the control unit determines to use the PRACH configuration parameters including a sequence length that is greater when GNSS information is not used than when GNSS information is used or in a TN environment. (Section 3) The terminal according to claim 1, wherein the control unit determines to use the PRACH configuration parameters including a cyclic prefix length that is larger when GNSS information is not used than when GNSS information is used or in a TN environment. (Section 4) The terminal according to claim 1, wherein the control unit determines to use a PRACH resource that is different from that used when GNSS information is not used or when GNSS information is used or in a TN environment. (Section 5) The terminal according to claim 1, wherein the control unit determines whether to use PRACH configuration parameters for when GNSS information is not used, based on a TA (Timing Advance) error, a frequency error, or GNSS accuracy. (Section 6) In an NTN (Non-Terrestrial Network) environment, when GNSS (Global Navigation Satellite System) information is not used, a procedure for determining to use PRACH (Physical random access channel) setting parameters different from those in a TN (Terrestrial Network) environment when GNSS information is used; and a procedure for transmitting a PRACH using the PRACH configuration parameters, wherein the terminal executes the communication method.

[0116] Any of the above configurations allows for proper execution of initial access in an NTN (Non-Terrestrial Network). Furthermore, according to paragraphs 2 to 5, even if GNSS information is not available in an NTN environment, initial access can be executed by specifying the resources and appropriate procedures required for initial access.

[0117] (Supplementary explanation of the embodiment) Although the embodiments of the present invention have been described above, the disclosed invention is not limited to such embodiments, and those skilled in the art will understand various modifications, alterations, alternatives, and substitutions. While specific numerical examples have been used to facilitate understanding of the invention, unless otherwise specified, these numerical values ​​are merely examples, and any appropriate values ​​may be used. The division of items in the above description is not essential to the present invention; two or more items may be combined as needed, and items described in one item may apply to items described in another item (unless inconsistent). The boundaries between functional units or processing units in the functional block diagram do not necessarily correspond to the boundaries between physical components. The operations of multiple functional units may be performed by a single physical component, or the operations of a single functional unit may be performed by multiple physical components. The order of the processing steps described in the embodiments may be reversed as long as there is no contradiction. For convenience of processing description, the base station 10 and terminal 20 have been described using functional block diagrams. However, such devices may be implemented using hardware, software, or a combination thereof. The software operated by the processor of the base station 10 in accordance with an embodiment of the present invention and the software operated by the processor of the terminal 20 in accordance with an embodiment of the present invention may each be stored in random access memory (RAM), flash memory, read-only memory (ROM), EPROM, EEPROM, registers, hard disk (HDD), removable disk, CD-ROM, database, server or any other suitable storage medium.

[0118] The aspects / embodiments described in the present disclosure may be categorized as Long Term Evolution (LTE), LTE-Advanced (LTE-A), International Mobile Telecommunications-Advanced (IMT-Advanced), 4th generation mobile communication system (4G), 5th generation mobile communication system (5G), 5G-Advanced (5G-A), 6th generation mobile communication system (6G), xth generation mobile communication system (x is, for example, an integer or a decimal number)), Future Radio Access (FRA), New Radio (NR), New radio access (NX), Future generation radio access (FX), Open Radio Access Network (O-RAN), Wideband Code Division Multiple Access (W-CDMA) (registered trademark), Global System for Mobile communications (GSM) (registered trademark), CDMA2000, Ultra Mobile Broadband (UMB), Institute of Electrical and Electronics Engineers (IEEE) Engineers) 802.11, IEEE802.11x (where x is any character string such as b, a, g, n, ac, ax, be, or bn, and when x=n it is called Wi-Fi4, when x=ac it is called Wi-Fi5, when x=ax it is called Wi-Fi6 or Wi-Fi6E, when x=be it is Wi-Fi7, and when x=bn it is called Wi-Fi8, etc. Wi-Fi is a registered trademark.), IEEE802.16 (WiMAX (registered trademark), IEEE802.20, UWB (Ultra-Wide Band), Bluetooth (registered trademark), network virtualization technology (e.g., NFV (Network Function Virtualization), SFC (Service Function Chaining), SDN (Software Defined Networking)), or LPWA (Low Power Wide Area). Furthermore, each aspect / embodiment described in the present disclosure may be applied to a system based on a combination of at least two of these technologies. Furthermore, "based on" naturally refers not only to a system that uses the technology, but also to a system that uses an extension or modification of the technology.

[0119] In the present disclosure, any two terms selected from a set of terms such as "base station (BS)", "radio base station", "fixed station (fixed station)", "NodeB", "eNodeB (eNB)", "gNodeB (gNB)", "access point (AP)", "transmission point (TP)", "reception point (RP)", "transmission / reception point (TRP)", "radio unit (RU)", "remote unit (RU)", "control unit (CU)", "distributed unit (DU)", "remote radio head (RRH)", "node", "gateway", "terrestrial base station", "stratospheric base station", "unmanned aerial vehicle", "high altitude platform station (HAPS)", "airborne platform", "panel", "cell", "radio access network (RAN)", and "network" may be used interchangeably.

[0120] Each cell accommodated by a base station may be referred to by terms such as a macro cell, a small cell, a femto cell, a pico cell, a serving cell, or a super cell. In the present disclosure, any two terms selected from a set of terms such as "cell," "sector," "cell group," "carrier," "component carrier," "cluster," "bandwidth part (BWP)," and "carrier bandwidth" may be used interchangeably.

[0121] In the present disclosure, any two terms selected from the set of terms such as "Mobile Station (MS)", "user terminal", "User Equipment (UE)", "Device", "Module" and "Terminal" may be used interchangeably.

[0122] A terminal may be referred to as a subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, handset, user agent, mobile client, client, router (e.g., home router, mobile router, etc.), TCU (Telematics Control Unit), or some other suitable terminology.

[0123] The base station and the terminal may each be composed of one or more devices. The devices constituting at least a portion of the base station and the terminal may be called a transmitting device, a receiving device, a communication device, etc. Note that the devices constituting at least a portion of the base station and the terminal may be, for example, an object itself, such as a vehicle, a transport vehicle, an automobile, a motorcycle, a bicycle, a connected car, an excavator, a bulldozer, a wheel loader, a dump truck, a forklift, a train, a bus, a handcar, a rickshaw, a ship and other watercraft, an airplane, a rocket, an unmanned aerial vehicle, a stratospheric base station (e.g., a High Altitude Platform Station (HAPS)), an artificial satellite (e.g., a Low Earth Orbit (LEO) satellite, a Medium Earth Orbit (MEO) satellite, a Geostationary Earth Orbit (GEO) satellite), a drone (registered trademark), a multicopter, a quadcopter, a balloon, or an Internet of Things (IoT) device (e.g., a smart meter, a sensor), or may include, but are not limited to, an object or device mounted on the object. Furthermore, the object may be a moving object (hereinafter referred to as a "moving object"; this does not exclude the case where the moving object is in a stationary state where it is not moving), or may be a fixedly positioned object (hereinafter referred to as a "non-moving object").

[0124] Furthermore, a base station in the present disclosure may be read as a terminal. For example, the aspects / embodiments of the present disclosure may be applied to a configuration in which communication between a base station and a terminal is replaced with communication between multiple terminals (which may be called, for example, D2D (Device-to-Device) or V2X (Vehicle-to-Everything)) or communication of a non-terrestrial network (NTN). In this case, the terminal 20 may be configured to have at least some of the functions of the base station 10 described above. Furthermore, terms such as "uplink" and "downlink" may be read as terms corresponding to communication between terminals (for example, "sidelink") or terms corresponding to NTN (for example, feeder link or service link). For example, an uplink channel or a downlink channel may be read as a sidelink channel.

[0125] The present disclosure is also applicable to cases where at least some of the devices constituting the base station and the terminal operate outside the earth (for example, in the atmosphere or outer space).

[0126] In addition, the term "terminal" in the present disclosure may be read as "base station." In this case, the base station 10 may be configured to have the functions of the terminal 20 described above.

[0127] The notification of information is not limited to the aspects / embodiments described in the present disclosure, and may be performed using other methods. For example, the notification of information may be performed by physical layer signaling (e.g., Downlink Control Information (DCI) and Uplink Control Information (UCI)), higher layer signaling (e.g., Radio Resource Control (RRC) signaling, Medium Access Control (MAC) signaling, broadcast information (Master Information Block (MIB) and System Information Block (SIB))), other signals, or a combination of at least two of these. Note that the physical layer signaling may be referred to as Layer 1 (L1) control information. The MAC signaling may be referred to as a MAC Control Element (CE) or a MAC Protocol Data Unit (PDU), for example. Furthermore, the RRC signaling may be referred to as an RRC message or an information element (IE) in the RRC message. The RRC message may be, for example, a message used for controlling an RRC connection (for example, setup, reconfiguration, establishment, reestablishment, release, or resume), mobility, a measurement report, or notification of a terminal's capabilities, or may be an information element within the message. Furthermore, notification of information may be explicit or implicit. Note that explicit notification of certain information means notification of the certain information itself, and implicit notification of certain information may mean notification of information other than the certain information, or may mean that the certain information is considered to have been notified when a certain condition is satisfied.Furthermore, notification of information may include not only notification between the same layers of different devices (e.g., between a lower layer or an upper layer of the base station 10 and the terminal 20) but also notification between different layers in the same or different devices (e.g., between a lower layer and an upper layer in the base station 10 or the terminal 20). Furthermore, notification of information from one device to another device may be performed via one or more devices. Regarding any information (e.g., a variable, a constant, a parameter, a setting) described in the present disclosure, even if not specifically stated in the above embodiments, information indicating / specifying (or related to) the any information (value) may be notified from any first device (e.g., a terminal / base station) to any second device (e.g., a base station / terminal).

[0128] The order of the procedures, sequences, flowcharts, etc. of each aspect / embodiment described in this disclosure may be changed unless it is consistent. For example, the methods described in this disclosure present elements of various steps using an example order, and are not limited to the particular order presented.

[0129] In the present disclosure, a specific operation described as being performed by a base station may be performed by its upper node or by some of its upper nodes (e.g., CU, RU, or DU, etc.) in some cases. It is clear that various operations performed for communication with a terminal in a RAN or core network may be performed by at least some of the base station and other network nodes other than the base station. The other network node may be one node or a combination of multiple nodes. The network node is, for example, a node provided in various core networks such as EPC (Evolved Packet Core) and 5GC (5G Core Network), and provides one or more network functions (NF: Network Functions), but is not limited to this.

[0130] Furthermore, in the present disclosure, the operation of "a terminal receives information from a base station" accompanies the operation of "the base station transmits the information to the terminal," "the base station generates the information," or both. Similarly, the operation of "a terminal transmits information to a base station" accompanies the operation of "the base station receives the information from the terminal." Furthermore, the operation of "a terminal is configured to ..." or "configure UE to ..." may include the operation of "a base station transmits configuration information regarding the configuration of the terminal" and the operation of "a terminal configures a predetermined operation based on the configuration information."

[0131] Each aspect / embodiment described in the present disclosure may be used alone, in combination, or switched depending on the implementation.

[0132] The present disclosure has been described above, but it is for illustrative purposes only, and the present invention is not limited to the aspects / embodiments described in the present disclosure. The present disclosure can be implemented in modified and altered forms without departing from the spirit of the invention. The present disclosure and its modifications and alterations are included in the scope of the present invention and its equivalents.

[0133] As used in this disclosure, any reference to an element using a designation such as "first," "second," etc. does not generally limit the quantity or order of those elements. These designations may be used in this disclosure as a convenient method of distinguishing between two or more elements. Thus, a reference to a first and a second element does not imply that only two elements may be employed or that the first element must in some way precede the second element.

[0134] The radio resource may be defined by a combination of resource units in one or more domains, such as the time domain, the frequency domain, the spatial domain, the code domain, and the power domain.

[0135] For example, resources in the time domain may be defined by one or more time units. The one or more time units may include, but are not limited to, a radio frame, a subframe, a slot, a symbol, a transmission time interval (TTI), or a combination of at least two of these. The time unit may be a fixed-length time unit independent of numerology, a variable-length time unit dependent on numerology, or both. Examples of fixed-length time units include, but are not limited to, a subframe consisting of one or more slots and a radio frame including multiple subframes. Examples of variable-length time units include, but are not limited to, a symbol and a slot including a fixed number of symbols. A certain time unit may be divided into shorter time units. Examples of shorter time units include, but are not limited to, a minislot consisting of fewer symbols than the number of symbols constituting a slot. The above-described time units may include, for example, time units used as units for scheduling, link adaptation, etc. Furthermore, any time unit in the present disclosure may be read as another time unit.

[0136] Numerology is a parameter that defines the physical layer structure, and may be a parameter based on at least one of subcarrier spacing (SCS), symbol length, cyclic prefix length, and sampling time, for example.

[0137] Resources in the frequency domain may be defined, for example, by one or more frequency units. The one or more frequency units may include, for example, subcarriers, resource blocks (RBs), bandwidth parts (BWPs), carrier bandwidths, or a combination of at least two of these, but the terminology of the frequency units is not limited to these. The number of subcarriers included in a frequency unit may be a fixed number regardless of numerology, or may be a variable number that changes depending on numerology. For example, an RB is composed of a predetermined number of consecutive subcarriers in the frequency domain, and the number of subcarriers included in the RB may be the same regardless of numerology, for example, 12, but is not limited to this. A BWP may be composed of, for example, one or more consecutive RBs within a certain carrier bandwidth, but is not limited to this. One or more BWPs may be configured within one carrier for terminal 20, and at least one of the BWPs may be activated. Any frequency unit in the present disclosure may be interchangeable with another frequency unit.

[0138] Furthermore, resources in both the time domain and the frequency domain may be defined by one or more time / frequency units each consisting of a time unit and a frequency unit, such as, but not limited to, a resource element (RE) consisting of one symbol and one subcarrier, a resource element group (REG) consisting of a predetermined number of REs, or a control resource set (CORESET) consisting of a predetermined number of symbols and a predetermined number of RBs.

[0139] Furthermore, resources in the spatial domain may be defined, for example, by one or more spatial units, including, but not limited to, a beam, a layer of MIMO (Multi-Input Multi-Output), an antenna port, or a combination of at least two of these.

[0140] Furthermore, the resources in the code domain may be defined by one or more code units, such as, but not limited to, a cyclic shift (CS), an orthogonal cover code (OCC), or a combination thereof.

[0141] In this disclosure, where articles are added by translation, such as a, an, and the in English, the disclosure may include that the nouns following these articles are in the plural form.

[0142] The "means" in the configuration of each of the above devices may be replaced with "part," "circuit," "device," etc. [Explanation of symbols]

[0143] 10 base station 110 Transmitter 120 Receiver 130 Setting section 140 Control Unit 20 terminals 210 Transmitter 220 Receiving unit 230 Setting Section 240 Control Unit 1001 processor 1002 Storage device 1003 Auxiliary storage device 1004 Communication equipment 1005 Input Device 1006 Output Device

Claims

1. A control unit that determines to use PRACH (Physical random access channel) setting parameters different from those used in a case where GNSS (Global Navigation Satellite System) information is not used or a case where TN (Terrestrial Network) information is used in a case where NTN (Non-Terrestrial Network) environment is used; A terminal having a communication unit that transmits a PRACH using the PRACH configuration parameters.

2. The terminal according to claim 1 , wherein the control unit determines to use the PRACH configuration parameters including a sequence length that is greater when GNSS information is not used than when GNSS information is used or in a TN environment.

3. The terminal according to claim 1 , wherein the control unit determines to use the PRACH configuration parameters including a cyclic prefix length that is greater when GNSS information is not used than when GNSS information is used or in a TN environment.

4. The terminal according to claim 1 , wherein the control unit determines to use a PRACH resource that is different from a PRACH resource that is used when GNSS information is not used or when GNSS information is used or in a TN environment.

5. The terminal according to claim 1 , wherein the control unit determines whether to use PRACH configuration parameters for when GNSS information is not used, based on a TA (Timing Advance) error, a frequency error, or GNSS accuracy.

6. In a non-terrestrial network (NTN) environment, when GNSS (Global Navigation Satellite System) information is not used, a procedure for determining to use PRACH (Physical random access channel) setting parameters different from those in a case where GNSS information is used or a terrestrial network (TN) environment; and a procedure for transmitting a PRACH by using the PRACH configuration parameters.

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