Terminal, base station, communication method and integrated circuit

Abstract

A terminal is provided with: a control circuit that determines an uplink channel resource on the basis of information relating to the position of the terminal; and a transmission circuit that transmits a signal of an uplink channel using the resource.

Description

Technical Field

[0001] The present disclosure relates to a terminal, a base station, a communication method, and an integrated circuit. Background Art

[0002] In terms of the standardization of 5G, a new radio access technology (NR) has been standardized by 3GPP (3rd Generation Partnership Project), and the specifications of Release 15 (Rel. 15) of NR have been released.

[0003] Prior Art Documents

[0004] Non-Patent Documents

[0005] Non-Patent Document 1: 3GPP, TR 38.821, V16.1.0 “Solutions for NR to support non-terrestrial networks (NTN) (Release 16)”

[0006] Non-Patent Document 2: 3GPP, TS 38.321, V17.2.0 “NR; Medium Access Control (MAC) protocol specification (Release 17)” Summary of the Invention

[0007] However, there is still room for research on methods for improving the reception quality of signals.

[0008] Non-limiting embodiments of the present disclosure help to provide a terminal, a base station, a communication method, and an integrated circuit capable of improving the reception quality of signals.

[0009] A terminal according to an embodiment of the present disclosure includes: a control circuit that determines resources of an uplink channel based on information related to the position of the terminal; and a transmission circuit that uses the resources to transmit a signal of the uplink channel.

[0010] It should be noted that these general or specific manners can be implemented by a system, a device, a method, an integrated circuit, a computer program, or a recording medium, or can be implemented by any combination of a system, a device, a method, an integrated circuit, a computer program, and a recording medium.

[0011] According to an embodiment of the present disclosure, the reception quality of signals can be improved.

[0012] More advantages and effects of one aspect of the present disclosure will be clarified in the specification and the drawings. These advantages and / or effects are respectively provided by several embodiments and the features described in the specification and the drawings, but it is not necessary to provide all of them in order to obtain one or more of the same features. Description of the Drawings

[0013] Figure 1 It is a diagram showing an example of a four-step random access procedure.

[0014] Figure 2 It is a block diagram showing a structural example of a part of a base station.

[0015] Figure 3 It is a block diagram showing a structural example of a part of a terminal.

[0016] Figure 4 It is a block diagram showing an example of the structure of a base station.

[0017] Figure 5 It is a block diagram showing an example of the structure of a terminal.

[0018] Figure 6 It is a flowchart showing an example of the operations of a base station and a terminal.

[0019] Figure 7 It is a diagram showing an example of the correspondence between a Physical Random Access Channel (PRACH) sequence or a Random Access Channel occasion (RO) and distance.

[0020] Figure 8 It is a diagram showing an example of the setting of PRACH resources.

[0021] Figure 9 It is a diagram showing an example of the setting of SSB (Synchronization Signal Block) beams and PRACH resources.

[0022] Figure 10 It is a diagram of an exemplary architecture of a 3GPP NR system.

[0023] Figure 11 It is a schematic diagram showing the functional separation between NG-RAN (Next Generation - Radio Access Network) and 5GC (5th Generation Core).

[0024] Figure 12It is a sequence diagram of the process of setting / resetting RRC (Radio Resource Control) connection.

[0025] Figure 13 It is a schematic diagram showing the usage scenarios of enhanced Mobile BroadBand (eMBB), massive Machine Type Communications (mMTC), and Ultra Reliable and Low Latency Communications (URLLC).

[0026] Figure 14 It is a block diagram showing an exemplary 5G system architecture for non-roaming scenarios. Detailed implementation manners

[0027] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0028] [Regarding non-terrestrial network (NTN: Non-Terrestrial Network)]

[0029] In NR Rel.15, it has been standardized as a radio access technology for terrestrial networks. On the other hand, in NR, the extension to non-terrestrial networks (NTN) such as communication using satellites or high-altitude platform stations (HAPS) has been studied (for example, Non-Patent Document 1).

[0030] In the NTN environment, the coverage area (for example, one or more cells) of a satellite for a terrestrial terminal (for example, also referred to as "user equipment (UE)") or a high-altitude terminal such as an aircraft or a drone is formed by a beam from the satellite (for example, also referred to as "satellite beam"). In addition, the round-trip time (RTT) of radio wave propagation between the terminal and the satellite depends on the height of the satellite (for example, up to about 36000 km) and the angle from the terminal, that is, depends on the positional relationship between the satellite and the terminal.

[0031] For example, Non-Patent Document 1 describes that the round-trip time (RTT) of radio wave propagation between a base station and a terminal in NTN can take up to about 540 ms at most.

[0032] In addition, Non-Patent Document 1 describes that in NTN, a time delay difference of up to about 10 ms (for example, the difference between the position farthest from the satellite and the position closest to the satellite within a beam (or coverage area or cell)) is generated according to the position of the terminal within the beam.

[0033] In addition, for example, in the case of a non-geostationary satellite such as a low-earth orbit satellite (LEO: Low Earth Orbit satellite), since the satellite moves at a high speed of about 7.6 km per second, the change in the propagation delay amount is drastic compared to the terrestrial network. In addition, in NTN, due to the high-speed movement of the satellite, a high Doppler frequency shift (or frequency shift) occurs compared to the terrestrial network.

[0034] [Regarding initial access]

[0035] In 5G NR, the terminal uses a random access channel (e.g., PRACH: Physical Random Access Channel) to send for initial access or data transmission requests, etc.

[0036] The random access process can be implemented, for example, by a four-step random access (e.g., also referred to as "four-step (4-step) RACH" or "Type-1 random access procedure"). Figure 1 It is a diagram showing an example of the four-step random access process.

[0037] As Figure 1 shown, as the first-step transmission (also denoted as "Message 1", "Msg.1", or "Msg1"), the terminal sends a PRACH. The PRACH is also referred to as a "preamble". The transmission of Msg.1 can be performed, for example, according to the transmission timing (e.g., slot timing) pre-notified to each cell by the base station (also called "gNB").

[0038] Next, after receiving and decoding Msg.1, the base station, as the second-step transmission (also denoted as "Message 2", "Msg.2", or "Msg2"), notifies the terminal of information such as the response to the PRACH (e.g., also called "RA response" or "Random Access Response (RAR)") and the scheduling information of the uplink transmission timing of Msg.3.

[0039] Next, as the third-step transmission (also denoted as "Message 3", "Msg.3", or "Msg3"), the terminal uses the scheduling information indicated by Msg.2 to notify the base station of information such as that for establishing a connection. The uplink data channel used for transmitting Msg.3 (e.g., PUSCH: Physical Uplink Shared Channel) is also referred to as "Msg.3 PUSCH".

[0040] Finally, as the fourth-step transmission (also denoted as "Message 4", "Msg.4", or "Msg4"), the base station uses a downlink data channel (e.g., PDSCH: Physical Downlink Shared Channel) to notify the terminal of a connection establishment response, etc. The time resources and frequency resources of the PDSCH used for transmitting Msg.4 (e.g., also referred to as "Msg.4 PDSCH") are notified to the terminal by the base station using a downlink control channel (e.g., PDCCH: Physical Downlink Control Channel (or Downlink Control Information (DCI))) before transmitting the PDSCH.

[0041] For example, the PRACH ( Figure 1 for four-step random access, Msg.1) can be composed of a CP (Cyclic prefix), a preamble sequence, and a GP (guard period). The preamble sequence can be, for example, a Cyclic-shifted Zadoff-Chu (CS-ZC) sequence with good correlation characteristics (a sequence obtained by cyclically shifting a ZC sequence), the CP can be a copy of a part of the preamble sequence, and the GP is a non-transmission interval.

[0042] For example, different CS-ZC sequences can uniquely correspond to each number of the preamble sequence (e.g., also referred to as "preamble number" or "PRACH number") and are notified to the terminal as cell information of the base station. The terminal transmits the CS-ZC sequence corresponding to the preamble number randomly selected from multiple preamble sequences as the PRACH. Even when multiple terminals transmit the PRACH in the same time resources and frequency resources, as long as the multiple terminals select different preamble numbers, the base station can simultaneously detect multiple preamble numbers through correlation detection of the CS-ZC sequences.

[0043] (Timing Control and Frequency Control)

[0044] In NR, for example, each terminal can perform timing control (e.g., timing adjustment) based on information for correcting (adjusting) timing notified by the base station (e.g., a so-called "Timing Advance (TA) command") so that the reception timing of signals transmitted from each terminal is consistent at the base station.

[0045] In NTN, as described above, compared with the terrestrial network, the amount of propagation delay changes drastically. Therefore, the terminal calculates the round-trip delay time between the terminal and the base station, corrects the timing, and transmits a signal.

[0046] For example, based on the position information of the terminal and information related to the orbit or position of the satellite, the delay time of the radio link (e.g., a so-called "service link") between the terminal and the satellite can be calculated. It should be noted that the position information of the terminal can be obtained, for example, by a Global Navigation Satellite System (GNSS) in the terminal. In addition, information related to the orbit or position of the satellite can be notified (e.g., broadcast) to the terminal by the base station as "ephemeris information (or also called 'ephemeris')", for example.

[0047] In addition, for example, the terminal can calculate the delay time of the radio link (e.g., a so-called "feeder link") between the terrestrial base station or gateway (GW) and the satellite based on the common TA parameter broadcast from the base station.

[0048] The delay time of the feeder link changes as the satellite moves. Therefore, for example, in addition to the delay time of the feeder link at a certain time point, information related to the amount of change in the delay time, such as the common TA drift and the common TA drift variation, can be notified to the terminal as the common TA parameter.

[0049] For example, the terminal can determine the value T for timing adjustment based on Equation (1). TA .

[0050] [Mathematical Formula 1]

[0051]

[0052] In Equation (1), N TA for example represents the TA value notified by the TA command, NTAoffset Indicates the offset relative to the TA value, T c Indicates the reference time (e.g., basic time unit). Additionally, in Equation (1), N TA,adj common Indicates the general TA value based on the feeder link delay time calculated according to the general TA parameters, N TA,adj UE Indicates the terminal-specific TA value based on the service link delay time estimated by the terminal according to the position information of the terminal and the satellite position. The first and second terms of Equation (1) are specified in, for example, 5G NR standard TS 38.211 and are the same as the Rel.15 NR specification. The T in Equation (1) TA value is the sum of the values of the first and second terms and the general TA value (N TA,adj common ) and the terminal-specific TA value (N TA,adj UE ).

[0053] In this way, in NTN, the round-trip delay time of the service link and the feeder link is corrected (e.g., compensated) on the terminal side, and the uplink signal is transmitted. As a result, the base station can receive the signals transmitted from each terminal within a specified time difference.

[0054] Additionally, in NTN, high Doppler frequency shift may occur due to the high-speed movement of the satellite. The Doppler frequency shift varies according to the terminal position and changes at all times. Therefore, it may be difficult for the base station to receive signals from multiple terminals. Therefore, the terminal can transmit signals using the frequency after pre-compensating the Doppler frequency shift of the service link. For example, the Doppler frequency shift is calculated based on the satellite position, satellite speed, and terminal position. Therefore, the terminal can calculate the Doppler frequency shift correction amount based on the satellite ephemeris information and the position information of the terminal.

[0055] The above describes the timing control and frequency control.

[0056] Since NTN is for long-distance transmission, in the case of using terminals such as ordinary smartphones, the transmission output and antenna gain are likely to decrease, and it may be difficult to communicate with satellites with high altitude or low elevation angle. Therefore, repetition transmission has been studied for NTN as a coverage enhancement.

[0057] Here, retransmission is supported in NR Release 16 (referred to as "NR Rel.16"), and retransmission is set for each terminal. For example, retransmission is set according to the high-layer setting specific to the terminal (or UE-specific, UE specific) (e.g., RRC setting (RRC configuration)). Therefore, in NR Rel.16, retransmission of signals before the high-layer setting specific to the terminal (e.g., signals used for initial access) is not supported.

[0058] In addition, in NR Release 17 (referred to as "NR Rel.17"), retransmission of Msg.3 PUSCH is supported. For example, the terminal measures the reception quality of the terminal (e.g., RSRP: Reference Signal Received Power or path loss, etc.), and based on the measurement result, selects a specific sequence of PRACH, thereby requesting retransmission of Msg.3 PUSCH from the base station.

[0059] In NR Release 18 (referred to as "NR Rel.18"), for example, in addition to studying the necessity of retransmission of Msg.3 PUSCH, the necessity of retransmission of PRACH (Msg.1) and the necessity of retransmission of the uplink control channel (e.g., PUCCH: Physical Uplink Control Channel) for the response to Msg.4 (Msg.4 PDSCH) (e.g., HARQ-ACK (Hybrid Automatic Repeat reQuest-ACKnowledgement)) are also studied.

[0060] In NR Rel.18, control methods for retransmission, such as the method for determining (or setting) the number of retransmissions for initial access in NTN and the method for notifying the terminal of information related to retransmission, have not been fully studied. In addition, for example, when applying the following method as a control method for retransmission, compared with the terrestrial network, the reception quality (e.g., received signal-to-noise ratio (SNR)) in NTN is likely to decrease, so the measurement accuracy of the quality such as RSRP decreases, and it may not be possible to appropriately control or set retransmission. The above method means that, similar to NR Rel.17, the terminal measures the reception quality of the terminal (RSRP or path loss, etc.) and selects a specific sequence of PRACH based on the measurement result.

[0061] In a non-limiting embodiment of the present disclosure, for example, a control method for repeated transmission for initial access is described. For example, a terminal may select (or determine, set) a resource of an uplink channel at initial access based on information related to the position of the terminal, and use the selected resource to transmit a specific channel or signal.

[0062] [Overview of Communication System]

[0063] A communication system according to an embodiment of the present disclosure includes a base station 100 and a terminal 200.

[0064] Figure 2 It is a block diagram showing a structural example of a part of the base station 100. In Figure 2 In the base station 100 shown, a control unit (for example, corresponding to a control circuit) determines a second resource of an uplink channel (for example, a resource of Msg.3 PDSCH or a PUCCH for HARQ-ACK transmission for Msg.4) based on a first resource of the uplink channel (for example, a resource of PRACH) determined according to information related to the position of the terminal 200. A receiving unit (for example, corresponding to a receiving circuit) uses the resource of the uplink channel to receive a signal of the uplink channel.

[0065] Figure 3 It is a block diagram showing a structural example of a part of the terminal 200. In Figure 3 In the terminal 200 shown, a control unit (for example, corresponding to a control circuit) determines a resource of an uplink channel (for example, a channel for a random access procedure) based on information related to the position of the terminal 200. A transmitting unit (for example, corresponding to a transmitting circuit) uses the resource to transmit a signal of the uplink channel.

[0066] (Embodiment 1)

[0067] In the present embodiment, the terminal 200 determines (or selects) a PRACH sequence based on the position information of the terminal 200, and uses the selected PRACH sequence to transmit a PRACH signal (Msg.1) to the base station 100. For example, the PRACH sequence may also be a routing sequence or a CS sequence. In addition, the PRACH sequence may be replaced with a RACH resource called "RACH occasion (RO)". In addition, the terminal 200 may also transmit a Msg.3 PUSCH that has been repeated corresponding to the selected PRACH sequence. In addition, the terminal 200 may also transmit a PUCCH for HARQ-ACK transmission for Msg.4 that has been repeated corresponding to the selected PRACH sequence.

[0068] [Structure of Base Station]

[0069] Figure 4 It is a block diagram showing an example of the structure of the base station 100 of the present embodiment. The base station 100 includes, for example, an antenna 101, a radio receiving unit 102, a PUSCH receiving processing unit 103, a PUCCH receiving processing unit 104, a PRACH receiving processing unit 105, a data generation unit 106, a control unit 107, a data transmission processing unit 108, and a radio transmission unit 109.

[0070] Figure 4 At least one of the PUSCH receiving processing unit 103, the PUCCH receiving processing unit 104, the PRACH receiving processing unit 105, the data generation unit 106, the control unit 107, and the data transmission processing unit 108 shown, for example, may be included in Figure 2 the control unit shown. Additionally, Figure 4 At least one of the antenna 101 and the radio receiving unit 102 shown, for example, may be included in Figure 2 the receiving unit shown.

[0071] The radio receiving unit 102, for example, performs receiving processing such as downconversion and A / D (Analog / Digital) conversion on a signal (for example, including a PUSCH (data signal), a PUCCH (control signal), or a PRACH (random access signal)) received from the terminal 200 via the antenna 101, and outputs the received and processed signal to the PUSCH receiving processing unit 103, the PUCCH receiving processing unit 104, and the PRACH receiving processing unit 105, respectively.

[0072] The PUSCH receiving processing unit 103, for example, performs channel estimation, demodulation processing, and decoding processing on a signal of the time resource and frequency resource allocated to the PUSCH in the received signal input from the radio receiving unit 102, and obtains a data sequence. The PUSCH receiving processing unit 103 outputs the decoded signal (data sequence).

[0073] The PUCCH receiving processing unit 104, for example, performs channel estimation, demodulation processing, and decoding processing on a signal of the time resource and frequency resource allocated to the PUCCH in the received signal input from the radio receiving unit 102, and obtains uplink control information (UCI: Uplink Control Information). In the UCI, for example, at least one of channel quality information (CQI: Channel Quality Information) and a response signal (for example, HARQ-ACK) may be included. The PUCCH receiving processing unit 104 outputs the decoded signal (UCI) to the control unit 107.

[0074] The PRACH reception processing unit 105, for example, detects a PRACH transmitted from the terminal 200 (determines whether there is a PRACH) and determines the PRACH sequence (e.g., PRACH sequence number) or RO (e.g., RO number) used by the detected PRACH for the signal in the received signal input from the wireless reception unit 102 that has been allocated time resources and frequency resources for the PRACH. The PRACH reception processing unit 105 outputs information related to the detected PRACH to the control unit 107.

[0075] The data generation unit 106 generates, for example, a downlink signal destined for each terminal 200 and outputs the generated downlink signal to the data transmission processing unit 108. Among the downlink signals generated in the data generation unit 106, at least one of signals such as user data (e.g., PDSCH), control signals (e.g., PDCCH), synchronization signal blocks (e.g., SSB: Synchronization Signal (SS) / Physical Broadcast Channel (PBCH) Block), reference signals (RS: Reference Signal), and medium access control (MAC: Medium Access Control) control information can be included.

[0076] The control unit 107 can generate, for example, system information such as a master information block (MIB: Master Information Block) or a system information block (SIB: System Information Block) (e.g., broadcast information) and dedicated control information (e.g., RRC control information). The control unit 107 outputs the generated information to the data transmission processing unit 108.

[0077] In the system information, for example, control information for NTN can also be included, and the control information for NTN includes at least one of parameters such as satellite ephemeris, general TA parameters, and epoch time. In addition, information related to the setting of PRACH resources can be included in the system information. In addition, in the system information, for example, information about the correspondence between the distance between the satellite and the terminal 200 and the PRACH sequence (hereinafter, sometimes also referred to as "information about the correspondence between the distance and the PRACH sequence") can also be included.

[0078] In addition, the control unit 107 generates downlink control information (DCI) or PDCCH that is attached to the PDSCH transmission. In the DCI, information related to the retransmission control of the PDSCH, such as a new data indicator (NDI) or a redundancy version (RV), information related to the modulation and coding scheme (MCS) of the PDSCH or PUSCH, resource allocation information for the PDSCH or PUSCH, resource allocation information for the PUCCH used for HARQ-ACK transmission for the PDSCH, etc. may be included. In addition, for example, in the resource allocation information, information related to the number of repetitions (repetition number) may also be included.

[0079] The control unit 107 can, for example, use the UCI input from the PUCCH reception processing unit 104 to perform retransmission control of the PDSCH and setting of the MCS. In addition, the control unit 107 decides (or sets), for example, at least one of the repetition number of the Msg.3 PUSCH and the repetition number of the PUCCH used for HARQ-ACK transmission for the Msg.4 PDSCH based on the information related to the detected PRACH (for example, PRACH sequence number or RO number) input from the PRACH reception processing unit 105. Then, the control unit 107 generates at least one of the resource allocation information of the Msg.3 PUSCH reflecting the decided repetition number and the resource allocation information of the PUCCH used for HARQ-ACK transmission for the Msg.4 PDSCH reflecting the decided repetition number, and outputs it to the data transmission processing unit 108.

[0080] The data transmission processing unit 108, for example, encodes and modulates the signal input from the data generation unit 106 and the signal input from the control unit 107, and outputs the modulated signal to the wireless transmission unit 109.

[0081] The wireless transmission unit 109, for example, performs transmission processing such as D / A (Digital / Analog) conversion, up-conversion, and amplification on the signal input from the data transmission processing unit 108, and transmits the processed wireless signal from the antenna 101.

[0082] [Structure of the terminal]

[0083] Next, an example of the structure of the terminal 200 will be described.

[0084] Figure 5FIG. 0 is a block diagram showing an example of the structure of the terminal 200 according to the present embodiment. The terminal 200 includes, for example, an antenna 201, a wireless receiving unit 202, a data receiving and processing unit 203, a control unit 204, a timing adjustment unit 205, a PUSCH transmission processing unit 206, a PUCCH transmission processing unit 207, a PRACH transmission processing unit 208, and a wireless transmission unit 209.

[0085] Figure 5 At least one of the data receiving and processing unit 203, the control unit 204, the timing adjustment unit 205, the PUSCH transmission processing unit 206, the PUCCH transmission processing unit 207, and the PRACH transmission processing unit 208 shown, for example, may be included in Figure 3 the control unit shown. In addition, Figure 5 At least one of the antenna 201 and the wireless transmission unit 209 shown, for example, may be included in Figure 3 the transmission unit shown.

[0086] The wireless receiving unit 202 performs reception processing such as down-conversion and A / D conversion on a downlink signal such as a data signal (e.g., PDSCH) or a control signal (e.g., PDCCH) received from the base station 100 via the antenna 201, outputs the received signal after the reception processing to the data receiving and processing unit 203, and outputs information on the reception timing of the signal to the timing adjustment unit 205.

[0087] The data receiving and processing unit 203 performs demodulation processing and decoding processing on the received signal (e.g., PDCCH or PDSCH) input from the wireless receiving unit 202. In the control signal (e.g., PDCCH), for example, resource allocation information of a downlink data signal (e.g., PDSCH), resource allocation information of an uplink data signal (e.g., PUSCH), or PUCCH resource allocation information for HARQ-ACK transmission for the PDSCH may be included. In addition, in the downlink data signal (e.g., PDSCH), for example, user data may be included. In addition, in the downlink data signal (e.g., PDSCH), information related to broadcast information such as system information, RRC control information, MAC control element (MAC CE) control information, RACH response (e.g., Msg.2), or TA command may also be included.

[0088] In addition, the data reception processing unit 203 performs reception processing on information for NTN (e.g., including at least one of satellite ephemeris, general TA parameters, and epoch time), information related to PRACH resources, and information on the correspondence between the distance between the satellite and the terminal 200 and the PRACH sequence contained in broadcast information or RRC control information (e.g., RRC Reconfiguration message), for example, and outputs the signal after the reception processing to the control unit 204. In addition, the data reception processing unit 203 outputs the control information contained in PDCCH and Msg.2 to the control unit 204, for example.

[0089] The control unit 204 calculates the distance between the terminal 200 and the satellite using the position information of the terminal 200 (e.g., information such as latitude, longitude, altitude, etc.) obtained by GNSS or the like, and the position information of the satellite calculated based on the information for NTN (e.g., information on satellite ephemeris and epoch time) input from the data reception processing unit 203. In addition, the control unit 204 selects a PRACH sequence (or RO) corresponding to the calculated distance between the terminal 200 and the satellite based on the information related to PRACH resources input from the data reception processing unit 203 and the information on the correspondence between the distance and the PRACH sequence (or RO).

[0090] In addition, the control unit 204 sets the resources of PUSCH or PUCCH based on the control information contained in the received PDCCH or Msg.2 input from the data reception processing unit 203. Here, for at least one of the resources of Msg.3 PUSCH and PUCCH for HARQ-ACK transmission for Msg.4 PDSCH, the control unit 204 may also determine the repetition number based on the PRACH sequence (e.g., resources based on the distance between the terminal 200 and the satellite) that has been selected for transmitting Msg.1, and set the resources corresponding to the determined repetition number.

[0091] In addition, the control unit 204 calculates the propagation delay amounts of the service link and the feeder link respectively based on the position information of the terminal 200, the position information of the satellite, and the information on general TA parameters, and outputs information related to the calculated propagation delay amounts to the timing adjustment unit 205. For example, the control unit 204 may calculate the propagation delay time of the service link based on the distance between the terminal 200 and the satellite and the radio wave propagation speed (about 3x10 8 m / s), and calculate the propagation delay time of the feeder link based on the general TA parameters. For example, the control unit 204 may calculate N TA,adj UE and N TA,adj common , and output them to the timing adjustment unit 205.

[0092] The timing adjustment unit 205 controls (e.g., adjusts) the transmission timing of a transmission signal (uplink signal), for example. The timing adjustment unit 205 outputs information related to timing adjustment to the wireless transmission unit 209. For example, the timing adjustment unit 205 can compensate for the propagation delay times of the serving link and the feeder link based on the information related to the propagation delay amounts of the serving link and the feeder link respectively input from the control unit 204, thereby adjusting the transmission timing of the uplink signal (e.g., PUSCH, PUCCH, or PRACH) so that the base station 100 receives the signal at a specified timing. The timing adjustment unit 205 can also perform timing adjustment according to Equation (1), for example.

[0093] The PUSCH transmission processing unit 206 performs encoding and modulation processing on the input transmission data (e.g., PUSCH), for example, and outputs a signal mapped to the time resources and frequency resources set in the control unit 204 to the wireless transmission unit 209.

[0094] The PUCCH transmission processing unit 207 performs encoding and modulation processing on control information (UCI) such as HARQ-ACK or CQI, for example, and outputs a signal mapped to the time resources and frequency resources set in the control unit 204 to the wireless transmission unit 209.

[0095] The PRACH transmission processing unit 208 generates a PRACH sequence selected in the control unit 204, for example, and outputs a signal mapped to the time resources and frequency resources set in the control unit 204 to the wireless transmission unit 209.

[0096] The wireless transmission unit 209 performs transmission processing such as D / A conversion, up-conversion, and amplification on the signal input from the PUSCH transmission processing unit 206, the PUCCH transmission processing unit 207, or the PRACH transmission processing unit 208, for example, and transmits the processed wireless signal from the antenna 201. The wireless transmission unit 209 can transmit the signal at a timing specified by the information input from the timing adjustment unit 205, for example.

[0097] [Operation examples of the base station and the terminal]

[0098] Next, operation examples of the base station 100 and the terminal 200 will be described.

[0099] Figure 6(a) is a flowchart showing an operation example of the base station 100, Figure 6 and (b) is a flowchart showing an operation example of the terminal 200.

[0100] The base station 100 periodically transmits broadcast information (e.g., SIB) (BS-ST1). In the SIB, for example, satellite ephemeris (e.g., the position information of the satellite), general TA parameters, PRACH resource information, and information on the relationship (corresponding relationship) between the PRACH sequence or RO and the distance can be included.

[0101] After the base station 100 transmits the broadcast information, for the set PRACH resources (e.g., time resources, frequency resources, or sequences), it waits for the PRACH (BS-ST2).

[0102] The terminal 200 receives the SIB sent from the base station 100 (UE-ST1), and uses the position information of the satellite (e.g., satellite ephemeris) contained in the SIB to calculate the distance between the terminal 200 and the satellite (UE-ST2). Then, the terminal 200 selects a PRACH sequence or RO corresponding to the calculated distance based on the information on the relationship between the PRACH sequence or RO and the distance, and uses the selected PRACH sequence or RO to send a PRACH for initial access (UE-ST3).

[0103] After the terminal 200 transmits the PRACH, it waits for a RACH response (e.g., RAR or Msg.2) (UE-ST4).

[0104] Figure 7 An example of the information indicating the relationship between the PRACH sequence (or RO) and the distance (the distance between the terminal 200 and the satellite). In Figure 7 the example, when the distance between the terminal 200 and the satellite is 600 - 749 km, the terminal 200 selects a PRACH sequence or RO from the PRACH sequence numbers or RO numbers 0 - 15. Similarly, in Figure 7 the example, when the distance between the terminal 200 and the satellite is 750 - 899 km, the terminal 200 selects a PRACH sequence or RO from the PRACH sequence numbers or RO numbers 16 - 31. The same applies to other distances.

[0105] In Figure 6 when the base station 100 detects (or receives) the PRACH, based on the PRACH sequence or RO used by the detected PRACH, it determines (or sets) at least one of the repetition number of Msg.3 PUSCH and the repetition number of PUCCH for HARQ-ACK transmission for Msg.4 (BS-ST3).

[0106] For example, the correspondence between the PRACH sequence or RO and the repetition number of each channel can be preset. For example, in the correspondence between the PRACH sequence or RO and the repetition number of each channel, it can also be that the PRACH sequence or RO with a longer distance between the corresponding terminal 200 and the satellite among multiple PRACH sequences or ROs corresponds to a larger number of repetitions. For example, for Figure 7 the PRACH sequence (or, RO) shown, it is also possible to make a larger number of repetitions correspond to a group (not shown) of PRACH sequence numbers (or, RO numbers) with a longer distance between the terminal 200 and the satellite.

[0107] The base station 100 sends a RACH response (RAR or Msg.2) (BS-ST4) containing information related to the determined repetition number of Msg.3 PUSCH to the terminal 200.

[0108] After sending the RACH response, the base station 100 waits for Msg.3 PUSCH (BS-ST5) in the resource allocated for Msg.3 PUSCH.

[0109] When the terminal 200 receives the RACH response, it uses the resource specified (or, indicated) by the received RACH response to send Msg.3 PUSCH (UE-ST5). For example, when the repetition number is specified by the RACH response, the terminal 200 can send Msg.3 PUSCH with the specified repetition number. Additionally, for example, when the repetition number is not specified by the RACH response, the terminal 200 can also send Msg.3 PUSCH without repetition.

[0110] Furthermore, for example, it is also possible to determine whether to specify the repetition number based on whether the terminal 200 selects a specific PRACH sequence notified by the SIB during the transmission of Msg.1. For example, it can also be that during the transmission of Msg.1, when a specific PRACH sequence is selected, the terminal 200 determines that the repetition number is specified, and when another PRACH sequence is selected, the terminal 200 determines that the repetition number is not specified. Additionally, for example, the repetition number can also be set separately for each specific PRACH sequence.

[0111] After the terminal 200 sends Msg.3 PUSCH, it waits for the DCI (UE-ST6) that allocates Msg.4 PDSCH. For example, the terminal 200 may also use a specified radio network temporary identifier (RNTI: Radio Network Temporary Identifier) to wait for the DCI. The specified RNTI may also be, for example, a temporary cell (TC: Temporary Cell)-RNTI. It should be noted that the specified RNTI is not limited to the TC-RNTI and may also be other RNTIs.

[0112] When the base station 100 receives Msg.3 PUSCH, it generates the DCI for allocating Msg.4 PDSCH and uses the PDCCH to send the DCI (BS-ST6). In the DCI, for example, information related to the number of repetitions of the PUCCH for HARQ-ACK transmission for Msg.4 determined in BS-ST3 may also be included. In addition, the base station 100 uses the resources allocated by the DCI to send Msg.4 PDSCH (BS-ST6).

[0113] When the terminal 200 receives the DCI that allocates Msg.4 PDSCH, it uses the resources allocated by the DCI to receive Msg.4 PDSCH (UE-ST7). In addition, when the terminal 200 has correctly decoded Msg.4 PDSCH, it uses the resources specified by the DCI to send a PUCCH that includes a HARQ-ACK indicating ACK (for example, also referred to as "Msg.4 HARQ-ACK"). When it cannot correctly decode Msg.4 PDSCH, it uses the resources specified by the DCI to send a PUCCH that includes a HARQ-ACK indicating NACK (UE-ST7). Here, when the terminal 200 is specified the number of repetitions by the DCI, it may send the PUCCH with the specified number of repetitions. In addition, for example, when the terminal 200 is not specified the number of repetitions by the DCI, it may also send a non-repeated PUCCH.

[0114] In addition, for example, it may also be determined whether to specify the number of repetitions according to whether the terminal 200 selects a specific PRACH sequence notified by the SIB during the Msg.1 transmission. For example, it may be that during the Msg.1 transmission, when a specific PRACH sequence is selected, the terminal 200 determines that the number of repetitions is specified, and when another PRACH sequence is selected, the terminal 200 determines that the number of repetitions is not specified. In addition, for example, the number of repetitions may also be set separately for each specific PRACH sequence.

[0115] The base station 100 waits for the HARQ-ACK for Msg.4 PDSCH (BS-ST7). If an ACK is received, the initial access process is completed. In the case where an ACK is not received, the DCI allocating Msg.4 PDSCH and Msg.4 PDSCH are sent again (BS-ST6), and retransmission processing is performed up to a specified number of times.

[0116] Above, the operation examples of the base station 100 and the terminal 200 have been described.

[0117] In this way, the terminal 200 can, for example, determine a sequence or RO (an example of a resource of an uplink channel) for the PRACH based on information about the distance between the terminal 200 and the satellite (an example of information related to the position of the terminal), and use the determined sequence or RO to transmit the PRACH (for example, Msg.1).

[0118] In addition, the base station 100 determines, for example, the number of repetitions of Msg.3 PDSCH or the PUCCH for HARQ-ACK transmission for Msg.4 PDSCH (an example of a second resource of an uplink channel) based on a sequence or RO (an example of a first resource of an uplink channel) for the PRACH determined based on information about the distance between the terminal 200 and the satellite (an example of information related to the position of the terminal), and uses the determined number of repetitions to receive Msg.3 PDSCH or the PUCCH for HARQ-ACK transmission for Msg.4 PDSCH.

[0119] Satellite communication is generally free-space propagation (for example, a line-of-sight (LOS) environment), so the propagation attenuation amount can be estimated based on the distance. In addition, the desired number of repetitions in satellite communication (for example, the number of repetitions required to meet the desired reception quality) depends on the propagation attenuation amount. Thus, the desired number of repetitions (for example, the number of repetitions required to meet the desired reception quality) can be estimated based on the distance between the terminal 200 and the satellite (or the positions of the terminal and the satellite).

[0120] In the present embodiment, the terminal 200 selects a PRACH sequence (or RO) based on the distance between the satellite and the terminal 200, and the base station 100 determines the number of repetitions of an uplink channel (for example, PUSCH or PUCCH) based on the detected PRACH sequence (or RO). That is, the number of repetitions of the uplink channel is determined depending on the distance between the satellite and the terminal 200. Here, the distance between the satellite and the terminal 200 is calculated using the position information that the terminal 200 has already obtained for timing adjustment or frequency adjustment. Thus, in the present embodiment, through a simple process of using the position information that has already been obtained for timing adjustment or frequency adjustment, communication using an appropriate number of repetitions can be performed.

[0121] In addition, since satellite communication is for long-distance transmission, it is likely to become communication with low SNR, and the measurement accuracy of the reception quality (e.g., RSRP) is likely to decrease. In the present embodiment, instead of using the reception quality, the distance between the satellite and the terminal 200 is used to determine the number of repetitions. Thus, according to the present embodiment, the desired number of repetitions can be estimated with high accuracy without relying on the reception quality (e.g., SNR). In addition, in the present embodiment, the terminal 200 does not need to measure the reception quality before transmitting the PRACH, so that simple and fast processing can be achieved.

[0122] In addition, based on the selection of the PRACH sequence (or RO) corresponding to the distance between the satellite and the terminal 200 by the terminal 200, the base station 100 can estimate the necessity of repetition for the uplink channel (e.g., PUSCH or PUCCH), or the desired number of repetitions. Therefore, the base station 100 can set appropriate numbers of repetitions for the Msg.3 PUSCH processed before the RRC setting (e.g., RRC re-setting) specific to the terminal, and the PUCCH for Msg.4 HARQ-ACK, thereby improving the reception quality of the Msg.3 PUSCH and the PUCCH for Msg.4 HARQ-ACK in the base station 100.

[0123] In view of the above, according to the present embodiment, the repeated transmission for the initial access in NTN can be appropriately controlled, so that the reception quality of the uplink signal can be improved.

[0124] It should be noted that although in Embodiment 1, the case where the base station 100 transmits a RACH response (RAR or Msg.2) including information related to the determined number of repetitions of the Msg.3 PUSCH is described, it is not limited thereto. For example, the base station 100 may also transmit a RACH response that does not include information related to the number of repetitions of the Msg.3 PUSCH. In this case, the terminal 200 may also determine the number of repetitions based on the PRACH sequence (or RO) already used in the Msg.1 transmission, and transmit the Msg.3 PUSCH with the determined number of repetitions. For example, information on the correspondence (corresponding relationship) between the PRACH sequence (or RO) and the number of repetitions of the Msg.3 PUSCH may also be notified to the terminal 200 by the SIB. Thus, the amount of information notified in the RACH response can be reduced, and the RACH response identical to that in Rel.15 / 16 can be used.

[0125] Similarly, although in Embodiment 1, it is described that the base station 100 transmits DCI including information related to the number of repetitions of the PUCCH for HARQ-ACK transmission for Msg.4, it is not limited thereto. For example, the base station 100 may also transmit DCI that does not include information related to the number of repetitions of the above PUCCH. In this case, the terminal 200 may also determine the number of repetitions based on the PRACH sequence (or RO) already used in Msg.1 transmission and transmit the PUCCH with the determined number of repetitions. For example, information on the correspondence (correspondence relationship) between the PRACH sequence (or RO) and the number of repetitions of the PUCCH for HARQ-ACK transmission for Msg.4 may also be notified to the terminal 200 by the SIB. Thereby, the amount of DCI notification information can be reduced, and thus the same DCI as in Rel.15 / 16 can be used.

[0126] In addition, although in Embodiment 1, it is described that the number of repetitions is set for both the Msg.3 PUSCH and the PUCCH for Msg.4 HARQ-ACK transmission, it is not limited thereto, and the setting of the number of repetitions may be applied to only one of them. In addition, for example, the number of repetitions set for the Msg.3 PUSCH and the PUCCH for Msg.4 HARQ-ACK transmission respectively may be the same (common) or different (may also be a dedicated setting).

[0127] In addition, the PRACH resource determined based on the distance between the terminal 200 and the satellite may be either one of the PRACH sequence and the RO, or both of them. The same applies to each of the embodiments described later.

[0128] (Embodiment 2)

[0129] The structures of the base station 100 and the terminal 200 in this embodiment may be the same as those in Embodiment 1, for example.

[0130] In this embodiment, the terminal 200 determines (or selects) the number of repetitions of the PRACH (Msg.1) based on the location information of the terminal 200 and transmits the PRACH with the selected number of repetitions.

[0131] In addition, in this embodiment, the terminal 200 transmits, for example, the Msg.3 PUSCH that has been repeated corresponding to the number of repetitions of the selected PRACH. In addition, the terminal 200 transmits, for example, the PUCCH for HARQ-ACK transmission for Msg.4 that has been repeated corresponding to the number of repetitions of the selected PRACH.

[0132] Describe the operations of the base station 100 and the terminal 200 in this embodiment that are different from those in Embodiment 1.

[0133] The base station 100 (e.g., the control unit 107) sets the setting information of the PRACH and the information on the correspondence relationship between the repetition number of the PRACH and the distance (e.g., the distance between the satellite and the terminal 200) as the information related to the PRACH resource. The set information can be, for example, included in the SIB and sent to the terminal 200. For example, in the setting information of the PRACH, the information related to the PRACH resource different from the repetition number can be included.

[0134] In addition, the base station 100 (e.g., the control unit 107) determines (or sets) at least one of the repetition number of the Msg.3 PUSCH and the repetition number of the PUCCH for HARQ-ACK transmission for the Msg.4 PDSCH based on the set information and according to the detected repetition number of the PRACH input from the PRACH reception processing unit 105. Moreover, the base station 100 can also receive the Msg.3 PUSCH and the PUCCH for HARQ-ACK transmission for the Msg.4 PDSCH based on the determined repetition number.

[0135] The terminal 200 (e.g., the control unit 204) calculates, for example, the distance between the terminal 200 and the satellite using the position information of the terminal 200 obtained by GNSS or the like and the position information of the satellite calculated based on the information for NTN (e.g., satellite ephemeris and epoch time) input from the data reception processing unit 203. Then, the terminal 200 selects the repetition number of the PRACH corresponding to the calculated distance based on the information related to the PRACH resource and the information on the correspondence relationship between the repetition number of the PRACH and the distance (e.g., the distance between the satellite and the terminal 200).

[0136] Figure 8 It is a diagram showing a setting example of the PRACH resource.

[0137] As Figure 8 shown in (a) of, the repetition number of the PRACH can also be the number of repetitions of the PRACH sequence transmitted in one RO (PRACH resource setting example 1). Figure 8 The example of (a) of shows the case where 6 PRACH sequences are repeatedly set in one RO (repetition number = 6) and the case where 2 PRACH sequences are repeatedly set (repetition number = 2).

[0138] In addition, in PRACH resource setting example 1, the repetition number can also be uniquely set for each PRACH sequence. For example, the repetition number 1 can be set for sequences 1 to 10, and the repetition number 4 can be set for sequences 11 to 20. Alternatively, in PRACH resource setting example 1, the repetition number can also be set independently of the PRACH sequence. For example, multiple candidate repetition numbers can be set for all sequences available for transmitting PRACH.

[0139] In addition, as Figure 8 shown in (b) of Figure 8 , the repetition number of PRACH can also be the number of ROs (PRACH resource setting example 2) used for one PRACH transmission. In the case of (b) of

[0140] , the terminal 200 transmits the PRACH in one or more ROs at different timings according to the repetition number. The same PRACH sequence can be set in multiple ROs, or different PRACH sequences can be set.

[0140] In Embodiment 2, other processes and operations can be the same as those in Embodiment 1.

[0141] In this way, in this embodiment, the terminal 200 determines the repetition number of PRACH based on the information related to the position of the terminal 200. According to this embodiment, in addition to the same effects as those in Embodiment 1, the repetition number of PRACH can also be appropriately set.

[0142] In addition, the base station 100 can also notify the terminal 200 of the information related to the repetition number of Msg.3 PUSCH in the same manner as in Embodiment 1. Similarly, the base station 100 can also notify the terminal 200 of the information related to the repetition number of the PUCCH used for HARQ-ACK transmission for Msg.4 PDSCH in the same manner as in Embodiment 1. For example, for Msg.3 PDSCH, the information related to the repetition number can be notified using a RACH response (or, RAR, Msg.2), and for the PUCCH used for HARQ-ACK transmission for Msg.4 PDSCH, the information related to the repetition number can be notified using a DCI including the allocation of Msg.4 PDSCH.

[0143] Alternatively, the terminal 200 may also determine (or select, set) at least one of the repetition number of Msg.3 PUSCH and the repetition number of PUCCH for HARQ-ACK transmission for Msg.4 PDSCH, for example, according to the determined repetition number of PRACH. In this case, there may be no information related to the repetition number sent from the base station 100 to the terminal 200. In addition, the repetition number of at least one of Msg.3 PUSCH and PUCCH for HARQ-ACK transmission for Msg.4 is not limited to being determined based on the repetition number of PRACH, and may also be determined based on the location information of the terminal 200 (for example, the distance between the terminal 200 and the satellite).

[0144] In addition, the terminal 200 may also determine the sequence (PRACH sequence) or RO for PRACH (Msg.1) based on the location information of the terminal 200, in the same manner as in Embodiment 1.

[0145] (Embodiment 3)

[0146] The structures of the base station 100 and the terminal 200 in this embodiment may be the same as those in Embodiment 1, for example.

[0147] In this embodiment, the terminal 200 determines (or selects) a PRACH sequence based on the TA value calculated according to the location information of the terminal 200, and uses the selected PRACH sequence to send PRACH.

[0148] In addition, the terminal 200, for example, sends Msg.3 PUSCH with repetitions corresponding to the selected PRACH sequence. In addition, the terminal 200, for example, sends PUCCH for HARQ-ACK transmission for Msg.4 with repetitions corresponding to the selected PRACH sequence.

[0149] Describe the operations of the base station 100 and the terminal 200 in this embodiment that are different from those in Embodiment 1.

[0150] The base station 100 (for example, the control unit 107) sets information regarding the correspondence between the TA value calculated in the terminal 200 and the PRACH sequence. The set information may be sent to the terminal 200, for example, included in the SIB.

[0151] In addition, the base station 100 (e.g., the control unit 107) determines (or sets) at least one of the number of repetitions of Msg.3 PUSCH and the number of repetitions of the PUCCH for HARQ-ACK transmission for Msg.4 PDSCH based on the set information and the detected PRACH sequence input from the PRACH reception processing unit 105. Moreover, the base station 100 may receive Msg.3 PUSCH and the PUCCH for HARQ-ACK transmission for Msg.4 PDSCH based on the determined number of repetitions.

[0152] For example, the correspondence between the PRACH sequence and the number of repetitions of each channel may be set in advance. For example, the correspondence between the PRACH sequence and the number of repetitions of each channel may also be such that a PRACH sequence with a larger corresponding TA value among multiple PRACH sequences corresponds to a larger number of repetitions.

[0153] The terminal 200 (e.g., the control unit 204) estimates the propagation delays of the serving link and the feeder link, for example, using the position information of the terminal 200 obtained by GNSS or the like and the position information of the satellite calculated based on the information for NTN (e.g., satellite ephemeris and epoch time) input from the data reception processing unit 203, and calculates N in Equation (1). TA,adj UE and N TA,adj common .

[0154] Next, the terminal 200 selects a PRACH sequence based on the correspondence between the TA value notified by the SIB and the PRACH sequence and the value calculated based on the propagation delay of the serving link (e.g., the propagation delay between the satellite and the terminal 200) (e.g., the value of N TA,adj UE ).

[0155] In Embodiment 3, other processes and operations may be the same as those in Embodiment 1.

[0156] Thus, in the present embodiment, the terminal 200 determines the PRACH resource (e.g., the PRACH sequence) based on the TA value calculated based on the position of the terminal 200 and the position of the satellite.

[0157] In satellite communication, the propagation attenuation amount depends on the propagation delay amount (e.g., the time taken for propagation). Additionally, in the terminal 200, the TA value is calculated based on the estimated value of the propagation delay amount for the round trip between the satellite and the terminal 200. Therefore, the propagation attenuation amount can be estimated based on the TA value calculated in the terminal 200. Additionally, as described in Embodiment 1, the desired number of repetitions (e.g., the number of repetitions required to meet the desired reception quality) in satellite communication depends on the propagation attenuation amount. Thus, the desired number of repetitions can be estimated based on the TA value calculated in the terminal 200. Accordingly, in the present embodiment, through a simple process of using the TA value that has already been obtained for timing adjustment in the terminal 200, communication using an appropriate number of repetitions can be performed.

[0158] Furthermore, in the present embodiment, the terminal 200 selects the PRACH sequence based on the TA value. As a result, the base station 100 can estimate the necessity for repetition or the desired number of repetitions for the uplink channel (e.g., PUSCH or PUCCH) based on the detected PRACH sequence. Therefore, the base station 100 can set an appropriate number of repetitions for Msg.3 PUSCH and PUCCH for Msg.4 HARQ-ACK, which are processed before the individual RRC setting (e.g., RRC re-setting) of the terminal.

[0159] In addition, although the case of determining the PRACH sequence based on the TA value has been described in the present embodiment, it is not limited thereto. For example, similar to Embodiment 1 or Embodiment 2, at least one of the PRACH sequence, RO, and PRACH repetition number may be determined based on the TA value.

[0160] In addition, although the case of using the value of N TA,adj UE as the TA value has been described in the present embodiment, it is not limited thereto, and other values related to timing control may also be used.

[0161] Moreover, the base station 100 may, similar to Embodiment 1, notify the terminal 200 of information related to the number of repetitions of Msg.3 PUSCH. Similarly, the base station 100 may, similar to Embodiment 1, notify the terminal 200 of information related to the number of repetitions of the PUCCH for HARQ-ACK transmission for Msg.4 PDSCH. For example, for Msg.3 PDSCH, information related to the number of repetitions may be notified using a RACH response (or, RAR, Msg.2), and for the PUCCH for HARQ-ACK transmission for Msg.4 PDSCH, information related to the number of repetitions may be notified using a DCI including the allocation of Msg.4 PDSCH.

[0162] Alternatively, the terminal 200 may also determine (or select, set) at least one of the repetition number of Msg.3 PUSCH and the repetition number of PUCCH for HARQ-ACK transmission for Msg.4 PDSCH based on the determined PRACH resources (e.g., PRACH sequence, RO, PRACH repetition number). In this case, there may be no information related to the repetition number sent from the base station 100 to the terminal 200. It should be noted that at least one of the repetition numbers of Msg.3 PUSCH and the PUCCH for HARQ-ACK transmission for Msg.4 is not limited to being determined based on the PRACH resources, and may also be determined based on the TA value calculated in the terminal 200.

[0163] (Embodiment 4)

[0164] The structures of the base station 100 and the terminal 200 in this embodiment may be the same as those in Embodiment 1, for example.

[0165] In this embodiment, the terminal 200 determines (or selects) the repetition number of PRACH based on the detected SSB and transmits the PRACH with the selected repetition number. Here, the coverage areas on the ground are respectively formed by the beams corresponding to the respective SSBs (e.g., SSB beams), so the SSB detected in the terminal 200 depends on the position of the terminal 200. That is, the information about the SSB beam corresponding to the SSB received by the terminal 200 (e.g., SSB number) is included in the information related to the position of the terminal 200.

[0166] In addition, in this embodiment, the terminal 200 transmits, for example, Msg.3 PUSCH with repetitions corresponding to the repetition number of the selected PRACH. In addition, the terminal 200 transmits, for example, the PUCCH for HARQ-ACK transmission for Msg.4 with repetitions corresponding to the repetition number of the selected PRACH.

[0167] Describe the operations of the base station 100 and the terminal 200 in this embodiment that are different from those in Embodiment 1.

[0168] The base station 100 (e.g., the control unit 107) sets the setting information of PRACH and the information about the correspondence between the SSB number and the repetition number of PRACH as the information related to the PRACH resources. The set information may be sent to the terminal 200, for example, included in the SIB. For example, in the setting information of PRACH, the information related to the PRACH resources different from the repetition number may be included.

[0169] In addition, the base station 100 (e.g., the control unit 107) determines (or sets) at least one of the number of repetitions of Msg.3 PUSCH and the number of repetitions of the PUCCH for HARQ-ACK transmission for Msg.4 PDSCH based on the set information and the detected number of repetitions of the PRACH input from the PRACH reception processing unit 105. Further, the base station 100 may receive Msg.3 PUSCH and the PUCCH for HARQ-ACK transmission for Msg.4 PDSCH based on the determined number of repetitions.

[0170] The terminal 200 detects the SSB through cell search and, after detecting the SSB, receives the MIB and SIB. The terminal 200 selects the PRACH repetition number corresponding to the detected SSB (SSB number) based on, for example, the information related to the PRACH resource included in the SIB and the information on the correspondence between the SSB number and the number of repetitions of the PRACH.

[0171] Figure 9 It is a diagram showing a setting example of a PRACH resource (e.g., a PRACH sequence or an RO). Figure 9 (a) shows an example of the positional relationship between a satellite and SSB beams (e.g., SSB beam 1, SSB beam 2, SSB beam 3) radiated from the satellite. Figure 9 (b) shows an example of the correspondence between the SSB beam (or SSB number) and the number of repetitions of the PRACH.

[0172] As Figure 9 shown in (b), the base station 100 sets the PRACH resource with a repetition number of 4 for SSB beam 1 (SSB number 1), the PRACH resource with a repetition number of 2 for SSB beam 2 (SSB number 2), and the PRACH resource with a repetition number of 1 (e.g., no repetition) for SSB beam 3 (SSB number 3) in an associated manner. The base station 100 notifies the terminal 200 in the cell of the information on the correspondence between the SSB beam and the number of repetitions using the SIB.

[0173] As Figure 9 shown in (a), the farther the beam irradiates on the ground surface from the satellite (e.g., the beam with a lower elevation angle from the ground surface. In Figure 9 (a), it is SSB beam 1), the longer the distance between the terminal 200 and the satellite, and the closer the beam irradiates on the ground surface to the satellite (e.g., the beam with a higher elevation angle from the ground surface. In Figure 9 (a), it is SSB beam 3), the shorter the distance between the terminal 200 and the satellite.

[0174] Therefore, for example, it can be that, as Figure 9As shown in (b) of , the base station 100 sets a larger number of repetitions for the beam irradiated on the ground surface farther from the satellite, and sets a smaller number of repetitions for the beam irradiated on the ground surface closer to the satellite.

[0175] For example, in Figure 9 (a) of and Figure 9 (b) of , when the SSB beam 1 (SSB number 1) is detected (i.e., when in the coverage area of the SSB beam 1), the terminal 200 selects a PRACH sequence (or RO) with a repetition number of 4. Similarly, in Figure 9 (a) of and Figure 9 (b) of , when the SSB beam 2 (SSB number 2) is detected (i.e., when in the coverage area of the SSB beam 2), the terminal 200 selects a PRACH sequence (or RO) with a repetition number of 2, and when the SSB beam 3 (SSB number 3) is detected (i.e., when in the coverage area of the SSB beam 3), the terminal 200 selects a PRACH sequence (or RO) with a repetition number of 1 (i.e., no repetition).

[0176] In Embodiment 4, other processes and operations may be the same as those in Embodiment 1.

[0177] In this way, in this embodiment, the terminal 200 determines the repetition number of the PRACH based on the detected SSB beam. As a result, the terminal 200 in the area of the beam located at a position on the ground surface irradiated farther from the satellite can appropriately transmit the PRACH using a larger number of repetitions, thereby improving the reception quality of the PRACH in the base station 100.

[0178] In addition, the base station 100 can set the repetition number of the subsequent communication (Msg.3 PUSCH or Msg.4 HARQ-ACK) based on the detected repetition number of the PRACH. Therefore, the terminal 200 can perform Msg.3 PUSCH transmission and Msg.4 HARQ-ACK transmission with an appropriate repetition number.

[0179] In addition, although in Embodiment 4, the case of selecting the repetition number of the PRACH according to the SSB number detected by the terminal 200 is described, it is not limited thereto. For example, at least one of the PRACH sequence, RO, and repetition number may be determined based on the SSB number detected by the terminal 200.

[0180] In addition, when multiple SSBs are detected in the terminal 200, the SSB number with the highest received power (or received quality such as received SNR, etc.) among the multiple SSBs may also be used.

[0181] In addition, when the satellite moves like a LEO satellite, etc., when signals are transmitted from the satellite using fixed beams, the coverage areas of the respective beams (SSBs) on the ground also move in accordance with the movement of the satellite. Therefore, the distance between the satellite and the coverage areas of the respective beams does not change. In this case, the relationship between the SSB number and the PRACH repetition number may not be changed according to the movement of the satellite.

[0182] On the other hand, in the case where the directivity of the beam is controlled such that the same area is covered by the respective beams, the distance between the coverage area of each beam and the satellite changes due to the movement of the satellite. In this case, the base station 100 may change the relationship between the SSB number and the PRACH repetition number as the satellite moves, and notify this relationship to the terminal 200 using the SIB, or may also change the SSB number as the satellite moves. In the case of changing the SSB number as the satellite moves, for example, in the Figure 9 example, if the satellite moves away from the area of SSB beam 3, by changing the beam covering this area to SSB beam 1, a PRACH with a larger repetition number can be selected in this area.

[0183] In addition, the base station 100 may also notify the terminal 200 of information related to the repetition number of Msg.3 PUSCH in the same manner as in Embodiment 1. Similarly, the base station 100 may also notify the terminal 200 of information related to the repetition number of the PUCCH used for HARQ-ACK transmission for Msg.4 PDSCH in the same manner as in Embodiment 1. For example, for Msg.3 PDSCH, information related to the repetition number may also be notified using a RACH response (or, RAR, Msg.2), and for the PUCCH used for HARQ-ACK transmission for Msg.4 PDSCH, information related to the repetition number may also be notified using DCI including the allocation of Msg.4 PDSCH.

[0184] Alternatively, the terminal 200 may, for example, also determine (or, select, set) at least one of the repetition number of Msg.3 PUSCH and the repetition number of the PUCCH used for HARQ-ACK transmission for Msg.4 PDSCH based on the determined PRACH resources (for example, PRACH sequence, RO, PRACH repetition number). In this case, there may be no information related to the repetition number sent from the base station 100 to the terminal 200. It should be noted that at least one of the repetition number of Msg.3 PUSCH and the PUCCH used for HARQ-ACK transmission for Msg.4 is not limited to being determined based on the PRACH resources, and may also be determined based on the SSB beam (for example, SSB number) detected in the terminal 200.

[0185] The above has described various embodiments of the present disclosure.

[0186] (Other embodiments)

[0187] (1) Although in the above embodiments, it has been described that the resources for initial access (for example, one of the PRACH sequence, the PRACH repetition number, and the RO) are determined based on the position of the terminal 200 and the position of the satellite, it is not limited thereto. For example, the terminal 200 may also select the resources for initial access based on the position of the terminal 200 and a reference location.

[0188] The reference location is, for example, the center position of a cell (or, beam) on the ground surface, and is notified by the base station 100 to the terminal 200 using the SIB. Generally, the farther away from the cell center, the worse the pointing characteristics of the satellite beam, and thus the received signal quality is likely to deteriorate. Therefore, it may also be that the longer the distance between the terminal 200 and the reference location, the more the PRACH resources (for example, the PRACH sequence or the RO) with a larger repetition number are selected. Additionally, it may also be that the longer the distance between the terminal 200 and the reference location, the more the PRACH resources (for example, the PRACH sequence or the RO) with a larger repetition number of Msg.3 PUSCH or the repetition number of the PUCCH used for Msg.4 HARQ-ACK transmission are selected.

[0189] In addition, the selection of the resources for initial access based on the reference location may also be combined with at least one of Embodiments 1 to 4 (for example, the selection of the resources for initial access based on the satellite position). For example, the repetition number determined based on the satellite position may be further changed based on the reference location.

[0190] For example, when the distance between the terminal 200 and the reference location is greater than a specified threshold, a PRACH sequence with a larger repetition number (for example, twice the repetition number set based on the satellite position) may be selected. Additionally, when the distance between the terminal 200 and the reference location is below the threshold, a PRACH sequence with the repetition number set based on the satellite position may be selected, or a PRACH sequence with a repetition number less than the repetition number set based on the satellite position may be selected. Furthermore, the threshold may also be notified by the base station 100 to the terminal 200.

[0191] Thereby, the repetition number can be selected considering the directivity of the satellite beam. In addition, the reference location may also be the "referenceLocation" notified by SIB19.

[0192] (2) It is also possible to select PRACH resources (for example, one of a PRACH sequence, a PRACH repetition number, and an RO) based on the polarization control capability of the terminal 200.

[0193] Generally, satellites use circularly polarized waves (for example, left-hand circularly polarized waves (LHCP: Left hand circular polarization) or right-hand circularly polarized waves (RHCP: Right hand circular polarization)), while terminals for terrestrial cellular use linearly polarized waves (for example, vertical polarized waves (V polarized waves) or horizontal polarized waves (H polarized waves)). Therefore, when a satellite receives a signal transmitted from a terminal for terrestrial cellular, there may be a loss of about 3 dB.

[0194] For example, in the case where the terminal 200 can transmit a polarized wave signal of the same polarized wave as that used in the reception of the satellite (or the base station 100), the loss caused by the difference in polarized waves will be reduced. Therefore, when the terminal 200 can transmit a polarized wave signal of the same polarized wave as that used in the reception of the satellite (or the base station 100), it is also possible to select PRACH resources with a smaller repetition number (for example, a PRACH sequence or an RO), or a smaller PRACH repetition number. In addition, when the terminal 200 can transmit a polarized wave signal of the same polarized wave as that used in the reception of the satellite (or the base station 100), it is also possible to select PRACH resources (for example, a PRACH sequence or an RO) with a smaller repetition number for Msg.3 PUSCH or a PUCCH for Msg.4 HARQ-ACK transmission.

[0195] (3) Wireless performances such as antenna gain, polarized wave, and modulation and demodulation accuracy vary depending on the installation method of the terminal. When these wireless performances vary greatly among terminals, there may also be a large difference in the relationship between the distance between the terminal and the satellite and the reception quality, and it may be difficult to set an appropriate repetition number for all terminals.

[0196] Therefore, for example, it is also possible to stipulate the wireless performance of the terminal and apply the method of the above embodiment to the terminal 200 that meets the stipulation or the terminal 200 that has passed the test for these stipulations. In addition, for example, it is also possible to stipulate multiple levels of wireless performance, and the terminal 200 selects PRACH with a dedicated (for example, different) repetition number according to these wireless performance levels. In addition, the terminal 200 can also select a PRACH sequence or a PRACH repetition number by at least considering the estimated value of propagation loss, antenna gain, and polarized wave gain.

[0197] (4) The number of repetitions of the PUCCH for Msg.4 HARQ-ACK transmission can also be notified to the terminal 200, for example, by the following method. In the following method, the same format as the DCI for the terrestrial network is used to notify the number of repetitions. In addition, to ensure compatibility with Rel.15, 16, and 17, the DCI with the same number of bits as the DCI of Rel.15, 16, and 17 is used for notification without adding new bits for notifying the number of repetitions.

[0198] <Method 1>

[0199] In Method 1, the reserved field of DCI format 1_0 for notifying the resource allocation of Msg.4 PDSCH is used to notify the number of repetitions of the PUCCH for Msg.4 HARQ-ACK transmission.

[0200] The reserved field may be, for example, 2 bits of the downlink assignment index (DAI) field. In this case, one of the four (candidate) numbers of repetitions can be notified to the terminal 200 using the 2-bit reserved field. In addition, the four candidate numbers of repetitions can also be notified to the terminal 200 by the SIB.

[0201] In addition, the resource allocation notification of Msg.4 PDSCH is scrambled using the TC-RNTI. Therefore, the terminal 200 can also interpret the reserved field of DCI format 1_0 scrambled by the TC-RNTI as the notification field for the above-mentioned number of repetitions. In addition, "interpret" can be replaced, for example, with "determine", "judge", "decide", "calculate", or "understand".

[0202] <Method 2>

[0203] In Method 2, the PUCCH resource indicator (PRI) field of DCI format 1_0 for notifying the resource allocation of Msg.4 PDSCH is used to notify the number of repetitions of the PUCCH for Msg.4 HARQ-ACK transmission.

[0204] The PRI field is 3 bits. For example, 2 bits of the 3 bits can be used to notify the number of repetitions, and the remaining 1 bit can be used to notify the PUCCH resource. In this case, one of the four (candidate) numbers of repetitions can be notified to the terminal 200 using 2 bits of the PRI field. It should be noted that the four candidate numbers of repetitions can also be notified to the terminal 200 by the SIB.

[0205] In addition, the resource allocation notification of Msg.4 PDSCH is scrambled using TC-RNTI. Therefore, the terminal 200 can also interpret the PRI field (e.g., a part of the PRI field) of DCI format 1_0 scrambled by TC-RNTI as the notification field for the above-mentioned repetition number.

[0206] It should be noted that the frequency resources for PUCCH are notified to the terminal 200 using PRI in a manner that the PUCCHs of different terminals do not conflict with each other. In Method 2, the PRI field is used to notify the repetition number, so the number of bits used to notify the PUCCH resources is reduced. However, the transmission of PUCCH for Msg.4 HARQ-ACK is performed by the terminal performing the initial access and not by other terminals in the connected state. Therefore, by controlling the PUCCH resources of other terminals in the connected state, it is easy to avoid the PUCCH conflict between the terminal transmitting Msg.4 HARQ-ACK and other terminals.

[0207] <Method 3>

[0208] In Method 3, the PDSCH-to-HARQ-timing-indicator field of DCI format 1_0 used to notify the resource allocation of Msg.4 PDSCH is used to notify the repetition number of the PUCCH for Msg.4 HARQ-ACK transmission.

[0209] The PDSCH-to-HARQ-timing-indicator field is 3 bits. For example, 2 bits out of the 3 bits can be used to notify the repetition number, and the remaining 1 bit can be used to notify the information about the timing relationship between PDSCH and HARQ feedback. In this case, one of the four (candidate) repetition numbers can be notified to the terminal 200 using 2 bits of the PDSCH-to-HARQ-timing-indicator field. In addition, the four candidate repetition numbers can also be notified to the terminal 200 by SIB.

[0210] In addition, the resource allocation notification of Msg.4 PDSCH is scrambled using TC-RNTI. Therefore, the terminal 200 can also interpret the PDSCH-to-HARQ-timing-indicator field (e.g., a part of the PDSCH-to-HARQ-timing-indicator field) of DCI format 1_0 scrambled by TC-RNTI as the notification field for the above-mentioned repetition number.

[0211] It should be noted that the time resources for PUCCH are notified to the terminal 200 by using the PDSCH-to-HARQ timing indicator, so as to avoid the downlink time slots in the case of a TDD (Time Domain Duplex) system, or to control in such a way that the PUCCHs of different terminals do not conflict with each other. In Method 3, the PDSCH-to-HARQ timing indicator field is used to notify the repetition number, so the number of bits used to notify the PUCCH resources is reduced. However, NTN is mainly an FDD (Frequency Domain Duplex) system, so the control for avoiding downlink time slots may not be necessary. In addition, the PUCCH for Msg.4 HARQ-ACK transmission is sent by the terminal that performs the initial access, not by other terminals in the connected state. Therefore, by controlling the PUCCH resources of other terminals in the connected state, the PUCCH conflict between the terminal sending Msg.4 HARQ-ACK and other terminals can be easily avoided.

[0212] <Method 4>

[0213] In Method 4, the transmit power control (TPC) field of DCI format 1_0 used to notify the resource allocation of Msg.4 PDSCH is used to notify the repetition number of the PUCCH for Msg.4 HARQ-ACK transmission.

[0214] The TPC field is 2 bits. For example, 1 bit of the 2 bits can be used to notify the repetition number, and the remaining 1 bit can be used to notify the TPC information. In this case, one of the two (candidate) repetition numbers can be notified to the terminal 200 by using 1 bit of the TPC field. It should be noted that the two candidate repetition numbers can also be notified to the terminal 200 by the SIB. Or, all 2 bits of the TPC field can be used to notify the repetition number. In this case, the terminal 200 can also transmit the PUCCH at the maximum power without using the TPC bit for transmit power control.

[0215] In addition, the resource allocation notification of Msg.4 PDSCH is scrambled by using the TC-RNTI. Therefore, the terminal 200 can also interpret the TPC field (for example, a part of the TPC field) of DCI format 1_0 scrambled by the TC-RNTI as the above-mentioned repetition number notification field.

[0216] In addition, the transmission power of the PUCCH is controlled by TPC to reduce interference to adjacent cells. In Method 4, the TPC field is used to notify the repetition number. Therefore, the number of bits for controlling the transmission power of the PUCCH is reduced. However, the transmission of the PUCCH for Msg.4 HARQ-ACK is performed by the terminal performing the initial access, not by other terminals in the connected state. Therefore, the frequency of repeated notification is low. Even if the PUCCH is transmitted with a large transmission power, the impact on interference to adjacent cells is small. In addition, since NTN is for long-distance communication, it can be considered that most terminals will transmit at the maximum power. Even if the transmission power is not controlled using the TPC field, the impact is small.

[0217] Above, Methods 1 to 4 have been described.

[0218] It should be noted that the possibility of all terminals performing repeated transmission of the PUCCH for transmitting Msg.4 HARQ-ACK is low. Therefore, for example, the terminal 200 that selects a specific range of PRACH sequences (or ROs) from among a plurality of PRACH sequences (or ROs) can replace a certain field of the DCI based on one of the above Methods 1 to 4, and thus can also receive the information on the repetition number. The range of the above PRACH sequences (or ROs) can also be notified to the terminal 200 by the SIB.

[0219] In addition, each of Methods 1 to 4 can also be used in combination with one of the above embodiments.

[0220] In addition, the DCI format, the field of the DCI, and the number of bits of the field for notifying the repetition number of the PUCCH for Msg.4 HARQ-ACK transmission are not limited to the above examples, and can also be other formats, fields, or other numbers of bits. In addition, the number of bits for notifying the repetition number of the PUCCH for Msg.4 HARQ-ACK transmission is not limited to the above examples, and can also be other numbers of bits. In addition, the category of the RNTI used for scrambling the DCI is not limited to TC-RNTI, and can also be other RNTIs. This DCI is used to notify the repetition number of the PUCCH for Msg.4 HARQ-ACK transmission.

[0221] Above, other embodiments have been described.

[0222] It should be noted that in one embodiment of the present disclosure, the same PRACH sequence in different ROs can also be regarded as different sequences. Or, the PRACH sequence can also be a sequence that spans multiple ROs.

[0223] In addition, the repeated (repetitive) transmission can be multiple transmissions of the same modulated signal, or multiple transmissions of signals obtained by performing different modulations or codings on the same data.

[0224] In addition, the number of retransmissions (repetition number) indicates the number of times the signal is transmitted, and the repetition number 1 can also be replaced with "no retransmission".

[0225] In addition, the PRACH sequence can also be, for example, a routing sequence or a CS sequence. In addition, the PRACH sequence can also be replaced with a RACH resource called "RO".

[0226] In addition, although the following has been described in the above embodiment, that is, using the SIB, the information on the correspondence relationship between parameters such as distance, TA value, and SSB number and the resources for initial access (for example, PRACH sequence, RO, or repetition number) is notified from the base station 100 to the terminal 200, and the terminal 200 selects the PRACH sequence based on the correspondence relationship, it is not limited thereto. For example, the information on the correspondence relationship between parameters such as distance, TA value, and SSB number and the range (or group) of resources for initial access (for example, PRACH sequence, RO, or repetition number) can also be notified from the base station 100 to the terminal 200 using the SIB. For example, the terminal 200 can also randomly select a resource from the notified range of resources for initial access (for example, PRACH sequence, RO, or repetition number).

[0227] An embodiment of the present disclosure can be used for different types of satellite communications such as low Earth orbit satellites (LEO), medium Earth orbit satellites (MEO), highly elliptical orbit satellites (HEO), or geostationary Earth orbit satellites (GEO) at different heights from the Earth's surface. For example, the information representing the relationship between the distance between the terminal 200 and the satellite and the resources for initial access (for example, PRACH sequence or repetition number) in Embodiments 1 and 2, and the information representing the relationship between the TA value and the resources for initial access (for example, PRACH sequence or repetition number) in Embodiment 3 can be set separately for each type of satellite (or the height of the satellite).

[0228] Although the above embodiments describe the case where the terminal 200 selects a PRACH sequence or a PRACH repetition number, and the base station 100 determines, sets, and / or notifies the terminal 200 of the number of repetitions required for Msg.3 PUSCH and / or the PUCCH for HARQ-ACK transmission for Msg.4 PDSCH based on the detected PRACH sequence or PRACH repetition number, it is not limited thereto. For example, in the case where the terminal 200 corresponds to the repetition of the PUCCH for HARQ-ACK transmission for Msg.4 PDSCH, or in the case where it is determined that retransmission is required based on location information or reception quality, the terminal 200 may also select a PRACH from a specific PRACH sequence. The specific PRACH sequence may also be notified from the base station 100 to the terminal 200 using the SIB. It may also be that when the base station 100 detects a PRACH of a specific PRACH sequence, it uses Msg.2 to instruct the terminal 200 to include the information on the number of repetitions in Msg.3 PUSCH, and the terminal 200 notifies the base station 100 of the information on the number of repetitions of the PUCCH for HARQ-ACK transmission for Msg.4 PDSCH in Msg.3 PUSCH. Generally, the amount of information that can be notified by PUSCH such as Msg.3 is larger than the amount of information that can be notified by selecting a PRACH sequence. Therefore, by the terminal 200 notifying the base station 100 of the information on the number of repetitions in Msg.3 PUSCH, more candidate repetition numbers can be notified.

[0229] Although the above embodiments describe operations based on a four-step random access procedure (e.g., a four-step RACH procedure), the random access procedure may also be a two-step random access procedure (e.g., also referred to as "two-step (2-step) RACH" or "Type-2 random access procedure"). In the case of two-step RACH, the sequence or the number of repetitions of the uplink signal (e.g., at least one of PRACH and PUSCH) transmitted as MsgA may also be selected in the terminal 200 based on the information related to location (or distance), TA value, or SSB described in one of Embodiments 1 to 4. Additionally, in the case of two-step RACH, the PUCCH for HARQ-ACK for Msg.4 in one of Embodiments 1 to 4 may be replaced with the PUCCH for HARQ-ACK for MsgB.

[0230] Although the above-described embodiment illustrates a case where the repetition numbers for Msg.3 PUSCH and the PUCCH for HARQ-ACK for Msg.4 are separately determined and notified to the terminal 200, it is not limited thereto. For example, the repetition number for the PUCCH for HARQ-ACK for Msg.4 may not be notified. In this case, for example, the terminal 200 may also use the same repetition number as the repetition number notified for Msg.3 PUSCH to transmit the PUCCH for HARQ-ACK for Msg.4. Alternatively, for example, the terminal 200 may also use a repetition number determined based on the repetition number notified for Msg.3 PUSCH to transmit the PUCCH for HARQ-ACK for Msg.4. For example, the relationship between the repetition number of Msg.3 PUSCH and the repetition number of the PUCCH for HARQ-ACK for Msg.4 may also be notified from the base station 100 to the terminal 200 using SIB according to an offset or a scaling factor. The offset may be, for example, information on the difference between the repetition number of Msg.3 PUSCH and the repetition number of the PUCCH for HARQ-ACK for Msg.4. The scaling factor may be, for example, information on the ratio of the repetition number of Msg.3 PUSCH to the repetition number of the PUCCH for HARQ-ACK for Msg.4. In addition, information on the combination of the repetition number of Msg3 PUSCH and the repetition number of the PUCCH for HARQ-ACK for Msg.4 may be notified using the RAR UL grant, which is the Msg.3 PUSCH scheduling information of the RACH response (RAR). For example, the information on the above combination may be notified by the MCS field of the RAR UL grant. In addition, candidate combinations of the repetition number of Msg3 PUSCH and the repetition number of the PUCCH for HARQ-ACK for Msg.4 may also be notified by SIB. Thereby, the amount of information notified for the repetition number of the PUCCH for HARQ-ACK for Msg.4 can be reduced. It should be noted that the repetition number for the PUCCH for HARQ-ACK for Msg.4 may be notified without notifying the repetition number of Msg.3 PUSCH.

[0231] In the above-described embodiment, the PUCCH for HARQ-ACK for Msg.4 may also be replaced with a PUCCH that includes HARQ-ACK information for the PDSCH notified by DCI scheduled by TC-RNTI scrambling of the CRC (Cyclic Redundancy Check) part.

[0232] In addition, in each of the above embodiments, the satellite ephemeris information, which is information related to the satellite position, may be broadcast by the system information or may be pre-retained by the terminal 200. In addition, the satellite ephemeris information may also be updated when communication is possible. In addition, the terminal 200 may also use information different from the satellite ephemeris information to determine the satellite position.

[0233] In addition, although examples of using GNSS such as GPS (e.g., position detection using satellite signals) have been described in each of the above embodiments, the present invention is not limited thereto. For example, position detection using a terrestrial cellular base station, position detection using a WiFi (registered trademark) signal or a Bluetooth (registered trademark) signal, position detection using an acceleration sensor, etc., or position detection using a combination of these detection methods may also be performed. In addition, altitude information may be obtained from a barometric pressure sensor or the like.

[0234] In addition, in each of the above embodiments, the cell may be an area defined by the received power of the SSB or the channel state information reference signal (CSI-RS: Channel State Information-Reference Signal) transmitted by the base station (or satellite), or may be an area defined by the geographical location. In addition, the cell in each of the above embodiments may also be replaced with a beam defined by the SSB.

[0235] In addition, although examples of the PRACH, Msg.3 PDSCH, and PUCCH for HARQ-ACK transmission for Msg.4 PDSCH have been described as the repeated uplink channels in each of the above embodiments, the repeated channels or signals are not limited to these. For example, the repeated uplink channel or signal may also be another channel or signal for transmission before performing high-layer settings dedicated to the terminal 200 (terminal-specific RRC settings).

[0236] In addition, at least two of the above embodiments may be combined. For example, the PRACH resource, the resource of the Msg.3 PDSCH, and the resource of the PDSCH for HARQ-ACK transmission for Msg.4 PDSCH may each be separately set based on different parameters among the three parameters of the distance between the terminal 200 and the satellite, the TA value, and the SSB beam. Or, for example, the PRACH resource, the resource of the Msg.3 PDSCH, and the resource of the PDSCH for HARQ-ACK transmission for Msg.4 PDSCH may also be set based on a combination of different parameters among the three parameters of the distance between the terminal 200 and the satellite, the TA value, and the SSB beam.

[0237] In addition, satellite ephemeris information and general TA parameter information can also be notified, for example, in NTN-Config of SIB19, respectively, as "EpochTime" and "TAInfo".

[0238] In addition, in each of the above embodiments, the base station can also be replaced with a "network".

[0239] In addition, in each of the above embodiments, the terminal 200 can also use other signals such as CSI-RS instead of the SSB signal to perform reception quality measurement.

[0240] In addition, although the transmission on the uplink from the terminal 200 to the base station 100 has been described in the above embodiments, one embodiment of the present disclosure is not limited thereto, and it can also be applied to data on the downlink from the base station 100 to the terminal 200 or a link between terminals 200 (for example, a sidelink). In addition, although the transmission of the signal at the time of initial access has been described as an example of the uplink transmission in the above embodiments, the transmission target is not limited to the signal at the time of initial access, and it can also be other signals or channels.

[0241] In addition, one embodiment of the present disclosure can be applied regardless of the type of satellite such as GEO, MEO, LEO, or HEO. In addition, one embodiment of the present disclosure can also be applied to non-terrestrial communications such as HAPS or drone base stations, for example.

[0242] In addition, although the NTN environment (for example, satellite communication environment) has been described by way of example in the above embodiments, the present disclosure is not limited thereto. The present disclosure can also be applied to other communication environments (for example, at least one terrestrial cellular environment in LTE and NR). For example, one embodiment of the present disclosure can also be applied to terrestrial communications in an environment where the cell size is large and the propagation delay between the base station 100 and the terminal 200 is longer (for example, above a threshold).

[0243] In addition, in the above embodiments, regarding the satellite communication method, the structure can be such that the base station function exists on the satellite (for example, "regenerative satellite"), or the base station function exists on the ground and the communication between the satellite relay base station and the terminal is relayed by the satellite (for example, "transparent satellite"). For example, in one embodiment of the present disclosure, the downlink and the uplink can also be a link between the terminal and the satellite or a link via the satellite.

[0244] In addition, the various parameters in the above-described embodiments are examples, and other values may also be used. For example, the PRACH sequence number, RO number, distance between the terminal 200 and the satellite, number of repetitions, SSB number, and number of SSBs are not limited to the values shown in the above examples.

[0245] In addition, the method for notifying the control information from the base station 100 to the terminal 200 is not limited to the above examples, and may be notified (or broadcast, indicated, set) by at least one of system information such as MIB and SIB, RRC control information, MAC control information, and downlink control information (DCI: Downlink Control Information). It may also be preset to the terminal 200 or may be predefined in the standard.

[0246] The base station may be referred to as a "gNodeB" or "gNB". In addition, the terminal may also be referred to as a "UE".

[0247] Time resource units such as system frames and subframes may also be replaced with time slots, mini-slots, frames, subframes, etc.

[0248] In addition, the expression "…… part" in the above-described embodiments may also be replaced with other expressions such as "…… circuitry", "…… device", "…… unit", or "…… module".

[0249] (Supplement)

[0250] Information indicating whether the terminal 200 supports the functions, operations, or processes shown in the above-described embodiments may also be sent (or notified) from the terminal 200 to the base station 100 as, for example, the capability information or capability parameters of the terminal 200.

[0251] The capability information may also include the following information elements (IE: Information Element), each of which individually indicates whether the terminal 200 supports at least one of the functions, operations, and processes shown in the above-described embodiments. Alternatively, the capability information may also include the following information elements, which indicate whether the terminal 200 supports a combination of two or more of the functions, operations, and processes shown in the above-described embodiments.

[0252] The base station 100 can, for example, determine (or decide or assume) the functions, actions, or processes supported (or not supported) by the source terminal 200 of the capability information based on the capability information received from the terminal 200. The base station 100 can perform actions, processes, or controls corresponding to the determination result based on the capability information. For example, the base station 100 can control the communication for NTN based on the capability information received from the terminal 200.

[0253] It should be noted that the terminal 200 does not support a part of the functions, actions, or processes shown in the above embodiments, which can also be replaced by the limitation of such a part of the functions, actions, or processes in the terminal 200. For example, information or requests related to such limitations can also be notified to the base station 100.

[0254] Information related to the capabilities or limitations of the terminal 200 can be defined, for example, in a standard, or can be implicitly notified to the base station 100 in association with information known to the base station 100 or information sent to the base station 100.

[0255] (Control signal)

[0256] In the present disclosure, the downlink control signal (or downlink control information) associated with an embodiment of the present disclosure can be, for example, a signal (or information) transmitted in the physical downlink control channel (PDCCH: Physical Downlink Control Channel) of the physical layer, or can also be a signal (or information) transmitted in the medium access control control element (MAC CE: Medium Access Control Control Element) or radio resource control (RRC: Radio Resource Control) of the higher layer. In addition, for the signal (or information), it is not limited to the case notified by the downlink control signal, and can be pre-specified in a specification (or standard), or can be pre-set in the base station and the terminal.

[0257] In the present disclosure, the uplink control signal (or, uplink control information) associated with an embodiment of the present disclosure may be, for example, a signal (or, information) transmitted in the PUCCH at the physical layer, or may be a signal (or, information) transmitted in the MAC CE or RRC at the higher layer. Additionally, regarding the signal (or, information), it is not limited to the case notified by the uplink control signal, and may be pre-specified in the specification (or, standard), or may be pre-set in the base station and the terminal. Additionally, the uplink control signal may also be changed to uplink control information (UCI), sidelink control information (SCI) in the first stage, or SCI in the second stage, for example.

[0258] (Base Station)

[0259] In an embodiment of the present disclosure, the base station may also be a transmission reception point (TRP), a cluster head, an access point, a remote radio head (RRH), an eNodeB (eNB), a gNodeB (gNB), a base station (BS), a base transceiver station (BTS), a master unit, a gateway, etc. Additionally, in sidelink communication, the role of the base station may also be assumed by the terminal. Additionally, a relay device that communicates between the relay high-level node and the terminal may replace the base station. Additionally, a roadside device may also replace the base station.

[0260] (Uplink / Downlink / Sidelink)

[0261] An embodiment of the present disclosure can be applied, for example, to any of the uplink, downlink, and sidelink. For example, an embodiment of the present disclosure can also be applied to the Physical Uplink Shared Channel (PUSCH), Physical Uplink Control Channel (PUCCH), Physical Random Access Channel (PRACH) in the uplink, the Physical Downlink Shared Channel (PDSCH), PDCCH, Physical Broadcast Channel (PBCH) in the downlink, or the Physical Sidelink Shared Channel (PSSCH), Physical Sidelink Control Channel (PSCCH), Physical Sidelink Broadcast Channel (PSBCH) in the sidelink.

[0262] It should be noted that PDCCH, PDSCH, PUSCH, and PUCCH are examples of a downlink control channel, a downlink data channel, an uplink data channel, and an uplink control channel, respectively. In addition, PSCCH and PSSCH are examples of a sidelink control channel and a sidelink data channel. In addition, PBCH and PSBCH are examples of a broadcast channel, and PRACH is an example of a random access channel.

[0263] (Data channel / Control channel)

[0264] An embodiment of the present disclosure can be applied, for example, to any channel in the data channel and the control channel. For example, the channel in an embodiment of the present disclosure can also be changed to a certain channel among PDSCH, PUSCH, PSSCH in the data channel, or PDCCH, PUCCH, PBCH, PSCCH, PSBCH in the control channel.

[0265] (Reference signal)

[0266] In one embodiment of the present disclosure, a reference signal is, for example, a signal known to both a base station and a mobile station, and is sometimes also referred to as a "Reference Signal (RS)" or a "pilot signal". The reference signal may be any reference signal among a demodulation reference signal (DMRS: Demodulation Reference Signal), a channel state information-reference signal (CSI-RS: Channel State Information-Reference Signal), a tracking reference signal (TRS: Tracking Reference Signal), a phase tracking reference signal (PTRS: Phase Tracking Reference Signal), a cell-specific reference signal (CRS: Cell-specific Reference Signal), and a sounding reference signal (SRS: Sounding Reference Signal).

[0267] (Time interval)

[0268] In one embodiment of the present disclosure, the unit of time resource is not limited to one or a combination of a time slot and a symbol. For example, it may be a frame, a superframe, a subframe, a time slot, a sub-slot, a mini-slot, or a time resource unit such as a symbol, an orthogonal frequency division multiplexing (OFDM: Orthogonal Frequency Division Multiplexing) symbol, or a single carrier-frequency division multiple access (SC-FDMA: Single Carrier-Frequency Division Multiplexing Access) symbol. It may also be other time resource units. In addition, the number of symbols included in one time slot is not limited to the number of symbols exemplified in the above embodiment, and may be other numbers of symbols.

[0269] (Frequency band)

[0270] One embodiment of the present disclosure can be applied to either a licensed band or an unlicensed band.

[0271] (Communication)

[0272] An embodiment of the present disclosure can be applied to any communication among communication between a base station and a terminal (Uu link communication), communication between terminals (Sidelink communication), and communication of vehicle-to-everything (V2X) wireless communication technology. For example, a channel in an embodiment of the present disclosure can also be changed to one of PSCCH, PSSCH, Physical Sidelink Feedback Channel (PSFCH), PSBCH, PDCCH, PUCCH, PDSCH, PUSCH, and PBCH.

[0273] In addition, an embodiment of the present disclosure can be applied to either a terrestrial network or a non-terrestrial network (NTN) that uses satellites or high-altitude pseudo satellites (HAPS). In addition, an embodiment of the present disclosure can also be applied to a terrestrial network with a large cell size and an ultra-wideband domain transmission network where the transmission delay is greater than the symbol length or the time slot length.

[0274] (Antenna port)

[0275] In an embodiment of the present disclosure, an antenna port refers to a logical antenna (antenna group) composed of one or more physical antennas. For example, an antenna port does not necessarily refer to a single physical antenna, and sometimes refers to an array antenna composed of multiple antennas. For example, it can be stipulated that the antenna port is not defined by the number of physical antennas, but as the smallest unit capable of a terminal sending a reference signal. In addition, an antenna port is sometimes also defined as the smallest unit weighted by a precoding vector.

[0276] <System Architecture and Protocol Stack of 5G NR>

[0277] To implement the next version of the fifth-generation mobile technology (also simply referred to as "5G") that includes the development of a new radio access technology (NR) operating in the frequency range up to 100 GHz, 3GPP is continuing its work. The first version of the 5G standard was completed at the end of 2017, and thus, it is possible to transition to the trial production of terminals (such as smartphones) compliant with the 5G NR standard and commercial deployment.

[0278] For example, the overall system architecture is envisioned to include the NG-RAN (Next Generation Radio Access Network) of gNBs. The gNB provides the termination of the user plane (SDAP (Service Data Adaptation Protocol) / PDCP (Packet Data Convergence Protocol) / RLC (Radio Link Control) / MAC / PHY (Physical Layer)) and the control plane (RRC) protocols on the UE side for NG radio access. gNBs are connected to each other via the Xn interface. In addition, gNBs are connected to the NGC (Next Generation Core) via the Next Generation (NG) interface. More specifically, they are connected to the AMF (Access and Mobility Management Function) (e.g., a specific core entity that executes the AMF) via the NG-C interface, and to the UPF (User Plane Function) (e.g., a specific core entity that executes the UPF) via the NG-U interface. Figure 10 Represents the NG-RAN architecture (e.g., refer to 3GPP TS 38.300 v15.6.0, section 4).

[0279] The protocol stack of the user plane of NR (e.g., refer to 3GPP TS 38.300, section 4.4.1) includes the PDCP (Packet Data Convergence Protocol (refer to section 6.4 of TS 38.300)) sublayer, the RLC (Radio Link Control (refer to section 6.3 of TS 38.300)) sublayer, and the MAC (Media Access Control (refer to section 6.2 of TS 38.300)) sublayer that are terminated on the network side in the gNB. In addition, a new sublayer of the Access Stratum (AS) (SDAP: Service Data Adaptation Protocol) has been introduced on top of the PDCP (e.g., refer to section 6.5 of 3GPP TS 38.300). In addition, the protocol stack of the control plane has been defined for NR (e.g., refer to TS 38.300, section 4.4.2). The overview of the functions of layer 2 is described in section 6 of TS 38.300. The functions of the PDCP sublayer, the RLC sublayer, and the MAC sublayer are listed in sections 6.4, 6.3, and 6.2 of TS 38.300 respectively. The functions of the RRC layer are listed in section 7 of TS 38.300.

[0280] For example, the media access control layer processes the multiplexing of logical channels, scheduling including the processing of various parameter sets, and various functions associated with the scheduling.

[0281] For example, the physical layer (PHY) is responsible for encoding, PHY HARQ (Physical Layer Hybrid Automatic Repeat Request) processing, modulation, multi-antenna processing, and the role of mapping signals to appropriate physical time-frequency resources. In addition, the physical layer processes the mapping of transport channels to physical channels. The physical layer provides services to the MAC layer in the form of transport channels. A physical channel corresponds to a set of time-frequency resources used to transmit a specific transport channel, and each transport channel is mapped to a corresponding physical channel. For example, among physical channels, the uplink physical channels include PRACH (Physical Random Access Channel), PUSCH (Physical Uplink Shared Channel), and PUCCH (Physical Uplink Control Channel), and the downlink physical channels include PDSCH (Physical Downlink Shared Channel), PDCCH (Physical Downlink Control Channel), and PBCH (Physical Broadcast Channel).

[0282] In the use cases / extended scenarios of NR, enhanced mobile broadband (eMBB), ultra-reliable low-latency communications (URLLC), and massive machine type communications (mMTC) with various requirements in terms of data rate, latency, and coverage may be included. For example, eMBB is expected to support a peak data rate of about three times the data rate provided by IMT-Advanced (International Mobile Telecommunications-Advanced) (20 Gbps in the downlink and 10 Gbps in the uplink) and an effective (user-experienced) data rate. On the other hand, in the case of URLLC, more stringent requirements are proposed for ultra-low latency (the latency of the user plane is 0.5 ms in UL and DL respectively) and high reliability (1 - 10^-5 within 1 ms). Finally, in mMTC, preferably, a high connection density (1,000,000 devices / km in an urban environment) 2 ), large coverage in a poor environment, and a battery with an extremely long lifespan (15 years) for low-cost devices are required.

[0283] Therefore, sometimes the parameter sets of OFDM (e.g., subcarrier spacing (SCS), OFDM symbol length, cyclic prefix (CP) length, number of symbols per scheduling interval) suitable for one use case are not valid for other use cases. For example, in low-latency services, preferably, a shorter symbol length than that of mMTC services is required (therefore, a larger subcarrier spacing) and / or a smaller number of symbols per scheduling interval (also referred to as "TTI (Transmission Time Interval)"). Moreover, in an extended scenario with a large delay spread of the channel, preferably, a longer CP length than that in a scenario with a shorter delay spread is required. The subcarrier spacing can also be optimized according to the situation to maintain the same CP overhead. More than one value of subcarrier spacing supported by NR is possible. Correspondingly, subcarrier spacings of 15 kHz, 30 kHz, 60 kHz... are currently considered. The symbol length Tu and the subcarrier spacing Δf are directly related by the formula Δf = 1 / Tu. Similar to the LTE system, the term "resource element" can be used to represent the smallest resource unit composed of one subcarrier for the length of one OFDM / SC-FDMA (Single-Carrier Frequency Division Multiple Access) symbol.

[0284] In the new radio system 5G-NR, for each parameter set and each carrier, resource grids of subcarriers and OFDM symbols are defined respectively in the uplink and downlink. Each element of the resource grid is called a "resource element", which is determined based on the frequency index in the frequency domain and the symbol position in the time domain (refer to 3GPP TS 38.211 v15.6.0).

[0285] <Functional Separation between NG-RAN and 5GC in 5G NR>

[0286] Figure 11 Represents the functional separation between NG-RAN and 5GC. The logical nodes of NG-RAN are gNB or ng-eNB. 5GC has logical nodes AMF, UPF, and SMF (Session Management Function).

[0287] For example, gNB and ng-eNB host the following main functions:

[0288] - Functions of radio resource management such as radio bearer control, radio admission control, connection mobility control, and dynamically allocating (scheduling) resources to the UE in both the uplink and downlink;

[0289] - IP (Internet Protocol) header compression, encryption, and integrity protection of data;

[0290] - Selection of the AMF when attaching the UE in cases where the route towards the AMF cannot be determined based on the information provided by the UE;

[0291] - Routing of user plane data towards the UPF;

[0292] - Routing of control plane information towards the AMF;

[0293] - Establishment and release of connections;

[0294] - Scheduling and transmission of paging messages;

[0295] - Scheduling and transmission of system broadcast information (initiated by the AMF or the operation, admission, maintenance function (OAM));

[0296] - Setting of measurements and measurement reports for mobility and scheduling;

[0297] - Packet marking of the transmission class in the uplink;

[0298] - Session management;

[0299] - Support for network slicing;

[0300] - Management of QoS (Quality of Service) flows and mapping for data radio bearers;

[0301] - Support for the UE in the RRC_INACTIVE (RRC inactive) state;

[0302] - Distribution function of NAS (Non-Access Stratum) messages;

[0303] - Sharing of the radio access network;

[0304] - Dual connectivity;

[0305] - Close cooperation between NR and E-UTRA (Evolved Universal Terrestrial Radio Access).

[0306] The Access and Mobility Management Function (AMF) hosts the following main functions:

[0307] - Function to terminate non-access stratum (NAS) signaling;

[0308] - Security of NAS signaling;

[0309] - Security control of the access stratum (AS);

[0310] - Core Network (CN) inter-node signaling for mobility between 3GPP access networks;

[0311] - Possibility of reaching an idle-mode UE (including control and execution of paging retransmission);

[0312] - Management of the registration area;

[0313] - Support for intra-system mobility and inter-system mobility;

[0314] - Access authentication;

[0315] - Access authorization including roaming privilege check;

[0316] - Mobility management control (subscription and policy);

[0317] - Support for network slicing;

[0318] - Selection of the Session Management Function (SMF).

[0319] In addition, the User Plane Function (UPF) hosts the following main functions:

[0320] - Anchor point for intra-RAT (Radio Access Technology) / inter-RAT mobility (where applicable);

[0321] - External PDU (Protocol Data Unit) session point for interconnection with data networks;

[0322] - Routing and forwarding of packets;

[0323] - Enforcement of policy rules for packet inspection and the user plane part;

[0324] - Reporting of service usage;

[0325] - Uplink classifier for supporting routing of traffic flows towards the data network;

[0326] - BranchingPoint for supporting multi-homed PDU sessions;

[0327] - QoS handling for the user plane (e.g., packet filtering, gating, UL / DL rate enforcement);

[0328] - Verification of uplink traffic (mapping of SDF (Service Data Flow) to QoS flows);

[0329] - Buffering of downlink packets and triggering function for downlink data notification.

[0330] Finally, the Session Management Function (SMF) hosts the following main functions:

[0331] - Session management;

[0332] - Allocation and management of IP addresses for the UE;

[0333] - Selection and control of the UPF;

[0334] - Provisioning function for traffic steering in the User Plane Function (UPF) to direct traffic to the appropriate destination;

[0335] - Enforcement of control plane policies and QoS;

[0336] - Notification of downlink data.

[0337] <Procedure for setting up and reconfiguring the RRC connection>

[0338] Figure 12 Represents several interactions between the UE, gNB, and AMF (5GC entities) when the UE in the NAS part transitions from RRC_IDLE (RRC idle) to RRC_CONNECTED (RRC connected) (refer to TS 38.300 v15.6.0).

[0339] RRC is a high-layer signaling (protocol) for the configuration of the UE and the gNB. Through this transition, the AMF prepares UE context data (which includes, for example, PDU session context, security keys, UE Radio Capability, UE Security Capabilities, etc.) and sends it to the gNB together with an INITIAL CONTEXT SETUP REQUEST. Then, the gNB and the UE activate AS security together. The gNB sends a SecurityModeCommand message to the UE, and the UE responds to the gNB with a SecurityModeComplete message to activate AS security. Then, the gNB sends an RRCReconfiguration message to the UE, and the gNB receives an RRCReconfigurationComplete from the UE for this RRCReconfiguration message, thereby performing the reconfiguration for setting Signaling RadioBearer 2 (SRB2) and Data Radio Bearer (DRB). For a signaling-only connection, since SRB2 and DRB are not configured, the steps related to RRC reconfiguration can be omitted. Finally, the gNB notifies the AMF that the configuration process is complete using an INITIAL CONTEXT SETUP RESPONSE.

[0340] Therefore, in the present disclosure, there is provided an entity (e.g., AMF, SMF, etc.) of a fifth-generation core network (5GC) that includes: a control circuit that, when operating, establishes a Next Generation (NG) connection with a g-node B (gNodeB); and a sending unit that, when operating, sends an initial context setup message to the g-node B via the NG connection to configure a signaling radio bearer between the g-node B and a user equipment (UE: User Equipment). Specifically, the g-node B sends radio resource control (RRC) signaling including a resource allocation configuration information element (IE: Information Element) to the UE via the signaling radio bearer. Then, the UE performs transmission in the uplink or reception in the downlink based on the resource allocation configuration.

[0341] <Usage Scenarios of IMT after 2020>

[0342] Figure 13Represents several use cases for 5G NR. In the 3rd generation partnership project new radio (3GPP NR), three use cases that support a variety of services and applications conceived through IMT-2020 have been studied. The planning and formulation of the specifications for the first phase of enhanced mobile broadband (eMBB) for high-capacity high-speed communication have been completed. In current and future operations, in addition to gradually expanding the support for eMBB, it also includes the standardization for ultra-reliable and low-latency communications (URLLC) and massive machine type communications (mMTC). Figure 13 Represents several examples of the envisioned usage scenarios of IMT after 2020 (for example, refer to Figure 2 ) of ITU-R M.2083).

[0343] The use cases of URLLC have strict requirements related to performance such as throughput, latency (delay), and availability. The use cases of URLLC are conceived as an enabling technology for applications such as wireless control of future industrial production processes or manufacturing processes, remote medical surgery, automation of power transmission and distribution in smart grids, and traffic safety. By identifying technologies that meet the requirements set by TR38.913, the ultra-high reliability of URLLC is supported. In NR URLLC of Release 15, as an important requirement, it includes the condition that the targeted user-plane latency is 0.5 ms in the UL (uplink) and 0.5 ms in the DL (downlink). The overall requirement for URLLC for a single packet transmission is that for a packet size of 32 bytes, the block error rate (BLER) is 1E-5 when the user-plane latency is 1 ms.

[0344] Considering the physical layer, a large number of available methods can be used to improve reliability. The current room for improving reliability includes defining an additional CQI (Channel Quality Indicator) table for URLLC, a more compact DCI format, retransmission of PDCCH, etc. However, as NR (important requirements for NR URLLC) becomes more stable and is further developed, this room can be expanded to achieve ultra-high reliability. The specific use cases of NR URLLC in Release 15 include augmented reality / virtual reality (AR (Augmented Reality) / VR (Virtual Reality)), e-health, e-safety, and mission-critical applications.

[0345] In addition, the technical enhancements for the objectives of NR URLLC aim to improve latency and increase reliability. The technical enhancements for improving latency include a set of configurable parameters, non-slot-based scheduling using flexible mapping, grant-free (pre-set grant) uplink, slot-level repetition in the data channel, and pre-emption in the downlink. Pre-emption means stopping the transmission that has been allocated resources and using the allocated resources for other transmissions that are requested later and need to meet the requirements of lower latency / higher priority. Therefore, the permitted transmission will be replaced by a later transmission. Pre-emption can be applied regardless of the specific service type. For example, the transmission of service type A (URLLC) can also be replaced by the transmission of service type B (eMBB, etc.). The technical enhancements related to increasing reliability include a dedicated CQI / MCS table with a target BLER of 1E-5.

[0346] The use cases of mMTC (massive machine type communication) are characterized by, typically, a very large number of the following connected devices that send a relatively small amount of data that is not susceptible to latency. For the devices, low cost and very long battery life are required. From the perspective of NR, using a very narrow bandwidth part is a solution that can save the power of the UE and extend its battery life.

[0347] As described above, it is expected that the room for improving reliability in NR will be further expanded. This is one of the important requirements for all cases. For example, important requirements related to URLLC and mMTC are high reliability or ultra-high reliability. From the wireless and network perspectives, reliability can be improved in several mechanisms. Generally speaking, there are two to three important areas that may contribute to improving reliability. These areas include compact control channel information, repetition of the data channel / control channel, and diversity related to the frequency domain, time domain, and / or spatial domain. These areas can be generally used to improve reliability regardless of the specific communication scenario.

[0348] Regarding NR URLLC, further use cases with more stringent requirements such as factory automation, transportation, and power transmission are envisioned. Stringent requirements refer to high reliability (up to the 10 -6 th level of reliability), high availability, a packet size of up to 256 bytes, and time synchronization of up to about several microseconds (μs) (able to correspond to the use case, and setting the value to 1 μs or several microseconds according to the frequency range and short latency of about 0.5 ms to 1 ms (e.g., setting the target user plane latency to 0.5 ms)).

[0349] Moreover, regarding NR URLLC, from the perspective of the physical layer, there can be several technical enhancements. These technical enhancements include the enhancement of the PDCCH (Physical Downlink Control Channel) related to compact DCI, the repetition of the PDCCH, and the increase in the monitoring of the PDCCH. In addition, the enhancement of UCI (Uplink Control Information) is related to the enhanced HARQ (Hybrid Automatic Repeat reQuest) and the enhancement of CSI feedback. In addition, there can be the enhancement of the PUSCH related to frequency hopping at the mini-slot level and the enhancement of retransmission / repetition. The term "mini-slot" refers to a transmission time interval (TTI) that contains fewer symbols than a slot (a slot has 14 symbols).

[0350] <QoS Control>

[0351] The QoS (Quality of Service) model of 5G is based on QoS flows and supports both QoS flows that require guaranteed flow bitrates (GBR: Guaranteed Bit Rate QoS flows) and QoS flows that do not require guaranteed flow bitrates (non-GBR QoS flows). Therefore, at the NAS level, a QoS flow is the finest-grained QoS division in a PDU session. The QoS flow is determined within the PDU session according to the QoS flow ID (QFI: QoS Flow ID) transmitted by the encapsulation header via the NG-U interface.

[0352] For each UE, the 5GC establishes more than one PDU session. For each UE, in association with the PDU session, the NG-RAN, for example, as described above with reference to Figure 12 establishes at least one data radio bearer (DRB). In addition, a DRB in a QoS flow newly added to the PDU session can also be set later (when to set depends on the NG-RAN). The NG-RAN maps the packets belonging to various PDU sessions to various DRBs. The NAS-level packet filters in the UE and the 5GC are used to associate UL packets and DL packets with QoS flows, and the AS-level mapping rules in the UE and the NG-RAN associate UL QoS flows and DL QoS flows with DRBs.

[0353] Figure 14 Represents the non-roaming reference architecture of 5G NR (refer to TS23.501 v16.1.0, section 4.23). The Application Function (AF) (for example, hosting Figure 13The external application server of the exemplified 5G service interacts with the 3GPP core network to provide services. For example, it accesses the Network Exposure Function (NEF) to support applications that affect the routing of services, or interacts with the policy framework (refer to the Policy Control Function (PCF)) for policy control (e.g., QoS control). Based on the operator's deployment, application functions that the operator deems trustworthy can directly interact with associated network functions. Application functions not allowed by the operator to directly access network functions interact with associated network functions via the NEF using an open framework for external use.

[0354] Figure 14 It also represents further functional units of the 5G architecture, namely, the Network Slice Selection Function (NSSF), the Network Repository Function (NRF), the Unified Data Management (UDM), the Authentication Server Function (AUSF), the Access and Mobility Management Function (AMF), the Session Management Function (SMF), and the Data Network (DN: Data Network, such as services provided by the operator, Internet access, or services provided by a third party). All or part of the functions of the core network and application services can also be deployed in a cloud computing environment and operate.

[0355] Therefore, in the present disclosure, the following application server (e.g., the AF of the 5G architecture) is provided, which includes: a transmission unit that, when operating, sends a request including QoS requirements for at least one of URLLC services, eMMB services, and mMTC services to at least one of the functions (e.g., NEF, AMF, SMF, PCF, UPF, etc.) of the 5GC in order to establish a PDU session including a radio bearer between the g-node B and the UE corresponding to the QoS requirements; and a control circuit that, when operating, uses the established PDU session to provide services.

[0356] The present disclosure can be implemented by software, hardware, or software in cooperation with hardware. Each functional block used in the description of the above embodiments is partially or wholly implemented as an LSI (Large Scale Integration) which is an integrated circuit. Each process described in the above embodiments can also be partially or wholly controlled by one LSI or a combination of LSIs. An LSI can be composed of individual chips, or can be composed of one chip in a manner that includes part or all of the functional blocks. An LSI can also include data input and output. Depending on the degree of integration, an LSI can also be referred to as an "IC (Integrated Circuit)", "System LSI", "Super LSI", or "Ultra LSI".

[0357] The method of integrating circuits is not limited to LSIs, and can also be implemented by dedicated circuits, general-purpose processors, or dedicated processors. Additionally, an FPGA (Field Programmable Gate Array) which can be programmed after the manufacture of an LSI, or a reconfigurable processor that can reconfigure the connections or settings of circuit blocks inside an LSI can be used. The present disclosure can also be implemented as digital processing or analog processing.

[0358] Furthermore, if with the progress of semiconductor technology or the derivation of other technologies, an integrated circuit technology that replaces LSIs emerges, of course, such technology can be used to achieve the integration of functional blocks. There is also the possibility of applying biotechnology and so on.

[0359] The present disclosure can be implemented in all kinds of devices, equipment, and systems with communication functions (collectively referred to as "communication devices"). The communication device may also include a wireless transceiver and processing / control circuitry. The wireless transceiver may also include a receiving section and a transmitting section, or perform the functions of these sections. The wireless transceiver (transmitting section, receiving section) may also include an RF (Radio Frequency) module and one or more antennas. The RF module may also include an amplifier, an RF modulator / demodulator, or devices similar to these. Non-limiting examples of communication devices include: telephones (mobile phones, smartphones, etc.), tablet computers, personal computers (PCs) (laptop computers, desktop computers, notebook computers, etc.), cameras (digital cameras, digital video cameras, etc.), digital players (digital audio / video players, etc.), wearable devices (wearable cameras, smartwatches, tracking devices, etc.), game consoles, e-book readers, remote health / telemedicine devices, transportation vehicles or means of transportation with communication functions (automobiles, airplanes, ships, etc.), and combinations of the above various devices.

[0360] The communication device is not limited to portable or mobile devices, but also includes all kinds of devices, equipment, and systems that are not portable or are fixed. For example, it includes: smart home devices (home appliances, lighting devices, smart meters or gauges, control panels, etc.), vending machines, and all other "Things" that can exist on the IoT (Internet of Things) network.

[0361] Communication includes not only data communication through cellular systems, wireless LAN (Local Area Network) systems, communication satellite systems, etc., but also data communication through combinations of these systems.

[0362] In addition, the communication device also includes devices such as a controller or a sensor that is connected or linked to a communication device that executes the communication function described in the present invention. For example, it includes a controller or a sensor that generates a control signal or a data signal used by the communication device that executes the communication function of the communication device.

[0363] In addition, the communication device includes infrastructure devices that communicate with or control the above-mentioned various non-limiting devices, such as base stations, access points, and all other devices, equipment, and systems.

[0364] A terminal according to an embodiment of the present disclosure includes: a control circuit that determines resources of an uplink channel based on information related to the position of the terminal; and a transmitting circuit that uses the resources to transmit a signal of the uplink channel.

[0365] In one embodiment of the present disclosure, the resource is at least one of a sequence for a random access channel, a transmission opportunity of the random access channel, and a number of repetitions of a signal transmitted during a random access procedure.

[0366] In one embodiment of the present disclosure, the uplink channel is at least one of the following channels in a random access procedure: a random access channel for Message 1 or Message A, an uplink data channel for Message 3, and an uplink control channel for a response to Message 4.

[0367] In one embodiment of the present disclosure, the uplink channel is a channel for transmission before high-layer settings dedicated to the terminal are performed.

[0368] In one embodiment of the present disclosure, the location-related information includes at least one of the following information: location information acquired by the terminal, information on the distance between the terminal and a satellite, information on the distance between the terminal and a reference location, information on a beam corresponding to a synchronization signal block received by the terminal, and information related to a timing advance value calculated based on the location of the terminal and the location of the satellite.

[0369] A base station according to one embodiment of the present disclosure includes: a control circuit that determines a second resource of the uplink channel based on a first resource of the uplink channel, the first resource being a resource determined based on information related to the location of a terminal; and a receiving circuit that uses the second resource to receive a signal of the uplink channel.

[0370] In a communication method according to one embodiment of the present disclosure, a terminal performs the following processing: determining a resource of an uplink channel based on information related to the location of the terminal; and using the resource to transmit a signal of the uplink channel.

[0371] In a communication method according to one embodiment of the present disclosure, a base station performs the following processing: determining a second resource of the uplink channel based on a first resource of the uplink channel, the first resource being a resource determined based on information related to the location of a terminal; and using the second resource to receive a signal of the uplink channel.

[0372] The disclosures of the specification, drawings, and abstract of the Japanese patent application No. 2022-158612 filed on September 30, 2022 are incorporated herein by reference in their entirety.

[0373] Industrial Applicability

[0374] One aspect of the present disclosure is useful for a wireless communication system.

[0375] Description of Reference Numerals

[0376] 100 Base Station

[0377] 101, 201 Antenna

[0378] 102, 202 Wireless Receiver

[0379] 103 PUSCH Reception Processing Unit

[0380] 104 PUCCH Reception Processing Unit

[0381] 105 PRACH Reception Processing Unit

[0382] 106 Data Generation Unit

[0383] 107 Control Unit

[0384] 108 Data Transmission Processing Unit

[0385] 109, 209 Wireless Transmitter

[0386] 200 Terminal

[0387] 203 Data Reception Processing Unit

[0388] 204 Control Unit

[0389] 205 Timing Adjustment Unit

[0390] 206 PUSCH Transmission Processing Unit

[0391] 207 PUCCH Transmission Processing Unit

[0392] 208 PRACH Transmission Processing Unit

Claims

1. A terminal, characterized in that, comprising: a control circuit that determines resources of an uplink channel based on information related to the position of the terminal; and a transmission circuit that uses the resources to transmit a signal of the uplink channel.

2. The terminal according to claim 1, wherein, the resources are at least one of a sequence for a random access channel, a transmission opportunity of the random access channel, and a number of repetitions of a signal transmitted during a random access process.

3. The terminal according to claim 1, wherein, the uplink channel is at least one of the following channels during a random access process, the channel being a random access channel for Message 1 or Message A, an uplink data channel for Message 3, and an uplink control channel for a response to Message 4.

4. The terminal according to claim 1, wherein, the uplink channel is a channel for transmission before performing high-layer settings specific to the terminal.

5. The terminal according to claim 1, wherein, the position-related information includes at least one of the following information, the information being position information obtained by the terminal, information about the distance between the terminal and a satellite, information about the distance between the terminal and a reference position, information about a beam corresponding to a synchronization signal block received by the terminal, and information related to a timing advance value calculated based on the position of the terminal and the position of the satellite.

6. A base station, characterized in that, comprising: a control circuit that determines a second resource of the uplink channel based on a first resource of the uplink channel, the first resource being a resource determined based on information related to the position of a terminal; and a reception circuit that uses the second resource to receive a signal of the uplink channel.

7. A communication method, characterized in that, the terminal performs the following processes: determining resources of an uplink channel based on information related to the position of the terminal; and using the resources to transmit a signal of the uplink channel.

8. A communication method, characterized in that, the base station performs the following processes: determining a second resource of the uplink channel based on a first resource of the uplink channel, the first resource being a resource determined based on information related to the position of a terminal; and using the second resource to receive a signal of the uplink channel.

9. An integrated circuit that controls the processing of a terminal, characterized in that, the processing includes: a process of determining resources of an uplink channel based on information related to the position of the terminal; and a process of using the resources to transmit a signal of the uplink channel.

10. An integrated circuit that controls the processing of a base station, characterized in that, the processing includes: a process of determining a second resource of the uplink channel based on a first resource of the uplink channel, the first resource being a resource determined based on information related to the position of a terminal; and a process of using the second resource to receive a signal of the uplink channel.

Images