Method and apparatus for transmitting and receiving a signal in a wireless communication system

Abstract

A method and apparatus for transmitting and receiving a signal in a wireless communication system according to an embodiment of the present application receives a random access channel (RACH) configuration and transmits a random access preamble on a specific RACH occasion (RO) based on the RACH configuration. The number of reference points in a cell is derived based on the number of RACH configurations, and the reference points can have respective initial timing advance (TA) values for a RACH procedure.

Description

Technical Field

[0001] This disclosure relates to a method and apparatus for use in a wireless communication system. Background Technology

[0002] Wireless communication systems are typically being developed to cover a wide range of diverse areas to provide communication services such as audio communication and data communication. Wireless communication is a multiple access system capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power). For example, multiple access systems can include one of the following: Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Orthogonal Frequency Division Multiple Access (OFDMA), and Single Carrier Frequency Division Multiple Access (SC-FDMA). Summary of the Invention

[0003] Technical issues

[0004] One aspect of this disclosure is to provide a method and apparatus for transmitting and receiving signals to efficiently perform signal transmission and reception processes in an NTN-enabled wireless communication system.

[0005] The technical tasks of this disclosure are not limited to those described above, and other technical tasks can be inferred from the embodiments of this disclosure.

[0006] Technical solution

[0007] This disclosure provides a method and apparatus for transmitting and receiving signals in a wireless communication system.

[0008] In one aspect of this disclosure, a method is provided for transmitting and receiving signals by a user equipment supporting a non-terrestrial network (NTN) in a wireless communication system, the method comprising: receiving information about a common timing advance (TA) value, and communicating with a base station based on the common TA value, wherein the information may include information about a plurality of common TA values ​​to be used during a specific time interval, and wherein the common TA values ​​may include TA values ​​applied between a satellite and a reference point.

[0009] In another aspect of this disclosure, a method is provided for transmitting and receiving signals by a base station supporting a non-terrestrial network (NTN) in a wireless communication system, the method comprising: transmitting information about a common timing advance (TA) value, and communicating with a user equipment based on the common TA value, wherein the information may include information about a plurality of common TA values ​​to be used during a specific time interval, and wherein the common TA values ​​may include TA values ​​applied between a satellite and a reference point.

[0010] In another aspect of this disclosure, a user equipment supporting a non-terrestrial network (NTN) for transmitting and receiving signals in a wireless communication system is provided. The user equipment includes at least one transceiver, at least one processor, and at least one memory operatively connected to the at least one processor and storing instructions that, when executed, enable the at least one processor to perform a specific operation, including: receiving information about a common timing advance (TA) value, and communicating with a base station based on the common TA value. The information may include information about multiple common TA values ​​to be used during a specific time interval, and the common TA values ​​may include TA values ​​applied between a satellite and a reference point.

[0011] In another aspect of this disclosure, a base station is provided that supports a non-terrestrial network (NTN) for transmitting and receiving signals in a wireless communication system. The base station includes at least one transceiver, at least one processor, and at least one memory operatively connected to the at least one processor and storing instructions that, when executed, enable the at least one processor to perform a specific operation, including: transmitting information about a common timing advance (TA) value and communicating with a user equipment based on the common TA value. The information may include information about multiple common TA values ​​to be used during a specific time interval, and the common TA values ​​may include TA values ​​applied between a satellite and a reference point.

[0012] In another aspect of this disclosure, an apparatus is provided for supporting a user equipment for a non-terrestrial network (NTT), the apparatus including at least one processor and at least one computer memory, the at least one computer memory being operatively connected to the at least one processor and enabling the at least one processor to perform operations when executed, the operations including operations of signal transmission and reception methods of the user equipment.

[0013] In another aspect of this disclosure, an apparatus for supporting a base station of a non-terrestrial network (NTT) is provided, the apparatus including at least one processor and at least one computer memory, the at least one computer memory being operatively connected to the at least one processor and enabling the at least one processor to perform operations when executed, the operations including operations of signal transmission and reception methods of the base station.

[0014] In another aspect of this disclosure, a computer-readable storage medium is provided, including at least one computer program that supports a non-terrestrial network (NTN) to enable at least one processor to perform operations, said operations including operations of signal transmission and reception methods for user equipment or base stations.

[0015] In the methods and apparatus described above, the information may include information about N common TA values ​​for a specific time interval that is divided into N time intervals.

[0016] In the methods and devices described above, the information may include a representative common TA value and a delta TA value, and during a specific time interval, the common TA value may be increased from the representative common TA value by the delta TA value in each configured time interval.

[0017] In the methods and apparatus described above, the information may include representative common TA values, and the common TA values ​​can be determined by updating the representative common TA values ​​based on the satellite's orbit, velocity, and / or position during a specific time interval.

[0018] In the methods and apparatus described above, the information may include information for each beam regarding multiple common TA values ​​to be used during the specific time interval.

[0019] The communication device may include at least user equipment, a network, and an autonomous vehicle communicating with another autonomous vehicle other than the communication device.

[0020] The foregoing aspects of this disclosure are merely some preferred embodiments thereof, and those skilled in the art can deduce and understand various embodiments reflecting the technical features of this disclosure from the following detailed description.

[0021] Beneficial effects

[0022] According to one embodiment of this disclosure, when performing signal transmission / reception in an NTN-enabled wireless communication system, signal transmission / reception can be performed more efficiently through operations different from those in the prior art.

[0023] The technical effects of this disclosure are not limited to those described above, and other technical effects can be inferred from the embodiments of this disclosure. Attached Figure Description

[0024] Figure 1 The diagram illustrates the structure of a radio frame.

[0025] Figure 2 The diagram illustrates the resource grid during the time slot duration.

[0026] Figure 3 The diagram illustrates a self-contained time slot structure.

[0027] Figure 4 The diagram illustrates the ACK / NACK transmission process.

[0028] Figure 5 The diagram illustrates an exemplary PUSCH transmission process.

[0029] Figure 6 An example of a wireless communication system used to support NTN is shown.

[0030] Figure 7 and Figure 8 The random access procedure is shown.

[0031] Figures 9 to 11 This is a diagram used to explain the NTN system and random access procedure according to embodiments of the present disclosure.

[0032] Figures 12 to 15 An apparatus according to an embodiment of the present disclosure is shown. Detailed Implementation

[0033] The following technologies can be used in various wireless access systems such as Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Orthogonal Frequency Division Multiple Access (OFDMA), and Single Carrier Frequency Division Multiple Access (SC-FDMA). CDMA can be implemented as radio technologies such as Universal Terrestrial Radio Access (UTRA) or CDMA2000. TDMA can be implemented as radio technologies such as Global System for Mobile Communications (GSM), General Packet Radio Service (GPRS), and Enhanced Data Rate GSM Evolution (EDGE). OFDMA can be implemented as radio technologies such as IEEE 802.11 (Wireless Fidelity (WiFi)), IEEE 802.16 (Global Microwave Access Interoperability (WiMAX)), IEEE 802.20, and Evolved UTRA (E-UTRA). UTRA is part of the Universal Mobile Telecommunications System (UMTS). The 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) is part of the Evolved UMTS using E-UTRA (E-UMTS), and LTE-Advanced (LTE-A) is an evolution of 3GPP LTE. 3GPP New Radio or New Radio Access Technology (NR) is an evolution of 3GPP LTE / LTE-A.

[0034] For clarity, this disclosure will be described in the context of 3GPP communication systems (e.g., LTE and NR), which should not be construed as limiting the spirit of this disclosure. LTE refers to technologies beyond 3GPP TS 36.xxx version 8. Specifically, LTE technologies beyond 3GPP TS 36.xxx version 10 are referred to as LTE-A, and LTE technologies beyond 3GPP TS 36.xxx version 13 are referred to as LTE-Apro. 3GPP NR is a technology beyond 3GPP TS 38.xxx version 15. LTE / NR may be referred to as a 3GPP system. “xxx” specifies the technical specification number. LTE / NR may be collectively referred to as a 3GPP system. Background techniques, terms, abbreviations, etc., as used herein refer to technical specifications published prior to this disclosure. For example, the following documents may be referenced.

[0035] 3GPP NR

[0036] -38.211: Physical Channel and Modulation

[0037] -38.212: Multiplexing and Channel Coding

[0038] -38.213: Physical layer process used for control

[0039] -38.214: Physical layer procedures for data

[0040] -38.300: General Description of NR and NG-RAN

[0041] -38.331: Radio Resource Control (RRC) Protocol Specification

[0042] Figure 1 The radio frame structure used for NR is shown.

[0043] In NR, UL and DL transmissions are configured on a frame-by-frame basis. Each radio frame is 10ms long and is divided into two 5ms half-frames. Each half-frame is further divided into five 1ms subframes. Subframes are divided into one or more time slots, and the number of time slots in a subframe depends on the subcarrier spacing (SCS). Depending on the cyclic prefix (CP), each time slot includes 12 or 14 OFDM(A) symbols. When using normal CP, each time slot includes 14 OFDM symbols. When using extended CP, each time slot includes 12 OFDM symbols. Symbols can include OFDM symbols (or CP-OFDM symbols) and SC-FDMA symbols (or Discrete Fourier Transform-Extended-OFDM (DFT-s-OFDM) symbols).

[0044] Table 1 exemplarily shows how the number of symbols per slot, the number of slots per frame, and the number of slots per subframe vary according to SCS under normal CP conditions.

[0045] [Table 1]

[0046] SCS(15*2^u) <![CDATA[N slot symb ]]> <![CDATA[N frame,u slot ]]> <![CDATA[N subframe，u slot ]]> 15kHz (u=0) 14 10 1 30kHz (u=1) 14 20 2 60kHz (u=2) 14 40 4 120kHz (u=3) 14 80 8 240kHz (u=4) 14 160 16

[0047] *N slot symb Number of symbols in a time slot

[0048] *N frame，u slot Number of time slots in a frame

[0049] *N Subframe,u slot Number of time slots in a subframe

[0050] Table 2 shows the number of symbols per slot, the number of slots per frame, and the number of slots per subframe that vary according to SCS under the extended CP case.

[0051] [Table 2]

[0052] SCS(15*2^u) <![CDATA[N slot symb ]]> <![CDATA[N frame，u slot ]]> <![CDATA[N subframe，u slot ]]> 60kHz (u=2) 12 40 4

[0053] In NR systems, different OFDM(A) parameter sets (e.g., SCS, CP length, etc.) can be configured for multiple cells aggregated for a UE. Therefore, the (absolute time) duration of time resources (e.g., subframes, slots, or transmission time intervals (TTI)) consisting of the same number of symbols (for convenience, referred to as time units (TU)) can be configured differently among the aggregated cells.

[0054] In NR, various parameter sets (or SCSs) can be supported to support a wide range of 5G services. For example, a 15kHz SCS can support wide areas in traditional cellular bands, while a 30kHz or 60kHz SCS can support dense urban areas, lower latency, and wide carrier bandwidth. For 60kHz or higher SCSs, bandwidths greater than 24.25kHz can be supported to overcome phase noise.

[0055] The NR band can be defined by two types of frequency ranges, FR1 and FR2. FR1 and FR2 can be configured as shown in Table 3 below. FR2 can be millimeter wave (mmW).

[0056] [Table 3]

[0057] Frequency range specification Corresponding frequency range Subcarrier spacing FR1 450MHz-7125MHz 15, 30, 60kHz FR2 24250MHz-52600MHz 60, 120, 240kHz

[0058] Figure 2 This shows the resource grid during the duration of a time slot.

[0059] A time slot comprises multiple symbols in the time domain. For example, a time slot may contain 14 symbols in normal CP and 12 symbols in extended CP. A carrier comprises multiple subcarriers in the frequency domain. A resource block (RB) can be defined by multiple (e.g., 12) consecutive subcarriers in the frequency domain. Multiple RB interleavings (simply called interleavings) can be defined in the frequency domain. An interleaving m∈{0, 1, ..., M-1} can consist of (common) RBs {m, M+m, 2M+m, 3M+m, ...}. M represents the number of interleavings. A bandwidth portion (BWP) can be defined by multiple consecutive (physical) RBs ((P)RBs) in the frequency domain and corresponds to a set of parameters (e.g., SCS, CP length, etc.). A carrier may include up to N (e.g., five) BWPs. Data communication can be performed in active BWPs, and only one BWP can be enabled for a UE. Individual elements in a resource grid can be called resource elements (REs) and can be mapped to a complex symbol.

[0060] In a wireless communication system, the UE receives information from the BS in the downlink (DL) and transmits information to the BS in the uplink (UL). The information exchanged between the BS and the UE includes data and various control information, and various physical channels / signals exist depending on the type / purpose of the information exchanged. Physical channels correspond to a set of resource elements (REs) carrying information originating from higher layers. Physical signals correspond to a set of REs used by the physical layer but not carrying information originating from higher layers. Higher layers include the Media Access Control (MAC) layer, Radio Link Control (RLC) layer, Packet Data Convergence Protocol (PDCP) layer, Radio Resource Control (RRC) layer, etc.

[0061] DL physical channels include the Physical Broadcast Channel (PBCH), Physical Downlink Shared Channel (PDSCH), and Physical Downlink Control Channel (PDCCH). DL physical signals include the DL Reference Signal (RS), Primary Synchronization Signal (PSS), and Secondary Synchronization Signal (SSS). DL RS includes the Demodulation Reference Signal (DM-RS), Phase Tracking Reference Signal (PT-RS), and Channel State Information Reference Signal (CSI-RS). UL physical channels include the Physical Random Access Channel (PRACH), Physical Uplink Shared Channel (PUSCH), and Physical Uplink Control Channel (PUCCH). UL physical signals include UL RS. UL RS includes DM-RS, PT-RS, and Sounding Reference Signal (SRS).

[0062] Figure 3 The structure of the self-contained time slot is shown.

[0063] In NR systems, frames have a self-contained structure where the DL control channel, DL or UL data, and UL control channel can all be contained within a single time slot. For example, the first N symbols in a time slot (hereinafter, the DL control region) can be used to transmit the DL control channel, and the last M symbols in the time slot (hereinafter, the UL control region) can be used to transmit the UL control channel. N and M are integers greater than or equal to 0. The resource region between the DL control region and the UL control region (hereinafter, the data region) can be used for either DL data transmission or UL data transmission. For example, consider the following configuration. The parts are listed in chronological order.

[0064] In this disclosure, the base station (BS) can be, for example, a gNodeB (gNB).

[0065] DL physical channel / signal

[0066] (1) PDSCH

[0067] The PDSCH carries DL data (e.g., DL Shared Channel Transport Block (DL-SCH TB)). The TB is encoded into codewords (CWs) and then transmitted after scrambling and modulation processing. Each CW comprises one or more code blocks (CBs). One or more CBs can be grouped into a code block group (CBG). Depending on the cell configuration, the PDSCH can carry up to two CWs. Scrambling and modulation can be performed for each CW, and the modulation symbols generated from each CW can be mapped to one or more layers. Each layer can be pre-coded and mapped to a resource along with the DMRS, and transmitted on the corresponding antenna port. The PDSCH can be dynamically scheduled by the PDCCH (Dynamic Scheduling). Alternatively, the PDSCH can be semi-statically scheduled (Configured Scheduling (CS)) based on higher-layer (e.g., RRC) signaling (and / or Layer 1 (L1) signaling (e.g., PDCCH)). Therefore, in dynamic scheduling, PDSCH transmission is accompanied by PDCCH, while in CS, PDSCH transmission may not be accompanied by PDCCH. CS may include Semi-Persistent Scheduling (SPS).

[0068] (2)PDCCH

[0069] The PDCCH carries downlink control information (DCI). For example, the PDCCH (i.e., DCI) can carry: the transmission format and resource allocation of the DL-SCH; frequency / time resource allocation information on the uplink shared channel (UL-SCH); paging information on the paging channel (PCH); system information on the DL-SCH; time / frequency resource allocation information regarding higher-layer control messages such as random access responses (RARs) transmitted via the PDCCH; transmission power control commands; and information regarding the activation / deactivation of SPS / CS. Various DCI formats can be provided depending on the information in the DCI.

[0070] Table 4 shows the DCI format transmitted via PDCCH.

[0071] [Table 4]

[0072]

[0073] DCI format 0_0 can be used to schedule PUSCH based on TB (or TB level), and DCI format 0_1 ​​can be used to schedule PUSCH based on TB (or TB level) or PUSCH based on CBG (or CBG level). DCI format 1_0 can be used to schedule PDSCH based on TB (or TB level), and DCI format 1_1 can be used to schedule PDSCH based on TB (or TB level) or PDSCH based on CBG (or CBG level) (DL-licensed DCI). DCI formats 0_0 / 0_1 can be referred to as UL-licensed DCI or UL scheduling information, and DCI formats 1_0 / 1_1 can be referred to as DL-licensed DCI or UL scheduling information. DCI format 2_0 can be used to provide the UE with dynamic slot format information (e.g., dynamic SFI), and DCI format 2_1 can be used to provide the UE with downlink preemption information. A UE defined as a group can be provided with DCI format 2_0 and / or DCI format 2_1 on the group common PDCCH, which is a PDCCH defined for the UE group.

[0074] PDCCH / DCI may include Cyclic Redundancy Check (CRC), and the CRC can be masked / scrambled using various identifiers (e.g., Radio Network Temporary Identifier (RNTI)) depending on the owner or purpose of the PDCCH. For example, if the PDCCH is for a specific UE, the Cell RNTI (C-RNTI) can be used to mask the CRC. If the PDCCH is related to paging, the Paging RNTI (P-RNTI) can be used to mask the CRC. If the PDCCH is related to system information (e.g., System Information Block (SIB)), the System Information RNTI (SI-RNTI) can be used to mask the CRC. If the PDCCH is related to random access response, the Random Access RNTI (RA-RNTI) can be used to mask the CRC.

[0075] Table 5 shows the uses and transport channels of PDCCH according to RNTI type. Here, transport channel refers to the transport channel associated with the data carried by PDSCH / PUSCH scheduled by PDCCH.

[0076] [Table 5]

[0077]

[0078] For PDCCH, a fixed modulation scheme (e.g., Quadrature Phase Shift Keying (QPSK)) can be used. Depending on the aggregation level (AL), a PDCCH can include 1, 2, 4, 8, or 16 control channel elements (CCEs). A CCE can include 6 resource element groups (REGs), and a REG can be defined by an OFDMA symbol and a (P)RB.

[0079] PDCCH can be transmitted within a control resource set (CORESET). A CORESET corresponds to a set of physical resources / parameters used to carry PDCCH / DCI within a BWP. For example, a CORESET may include a set of REGs with a given set of parameters (e.g., SCS, CP length, etc.). A CORESET can be configured by system information (e.g., MIB) or UE-specific higher-layer (e.g., RRC) signaling. For example, the following parameters / information can be used to configure a CORESET. A UE can be configured with one or more CORESETs, and multiple CORESETs can overlap in the time / frequency domain.

[0080] -controlResourceSetId: This parameter / information indicates the identifier (ID) of the CORESET.

[0081] -frequencyDomainResources: This parameter / information indicates the frequency domain resources of CORESET. Frequency domain resources can be indicated by a bitmap, and each bit corresponds to a group of RBs (=6 consecutive RBs). For example, the most significant bit (MSB) of the bitmap corresponds to the first group of RBs in the BWP. The group of RBs corresponding to bits with a value of 1 can be allocated as frequency domain resources of CORESET.

[0082] -duration: This parameter / information indicates the time-domain resources of the CORESET. The duration parameter / information can indicate the number of consecutive OFDMA symbols included in the CORESET. For example, the duration has values ​​from 1 to 3.

[0083] -cce-REG-MappingType: This parameter / information indicates the mapping type from CCE to REG. Interleaved and non-interleaved types are supported.

[0084] -precoderGranullarity: This parameter / information indicates the precoder granularity in the frequency domain.

[0085] -tci-StatesPDCCH: This parameter / information indicates information about the Transport Configuration Indication (TCI) status of the PDCCH (e.g., TCI-StateID). The TCI status can be used to provide quasi-co-address (QCL) relationships between DL RSs (TCI status) in the RS set and PDCCH DMRS ports.

[0086] -tci-PresentInDCI: This parameter / information indicates whether the TCI field is included in the DCI.

[0087] -pdcch-DMRS-ScramblingID: This parameter / information indicates the information used for initializing the PDCCH DMRS scrambling sequence.

[0088] For PDCCH reception, the UE can monitor (e.g., blindly decode) the set of PDCCH candidates in a CORESET. A PDCCH candidate can refer to a CCE monitored by the UE for PDCCH reception / detection. PDCCH monitoring can be performed in one or more CORESETs in each active cell with PDCCH monitoring configured in the active DL BWP. The set of PDCCH candidates monitored by the UE can be defined as a PDCCH search space (SS) set. The SS set can be classified as a common search space (CSS) set or a UE-specific search space (USS) set.

[0089] Table 6 shows the PDCCH search space.

[0090] [Table 6]

[0091]

[0092] SS sets can be configured by system information (e.g., MIB) or UE-specific higher-layer (e.g., RRC) signaling. S (e.g., 10) or fewer SS sets can be configured in each DL BWP of the serving cell. For example, the following parameters / information can be provided for each SS set. Each SS set can be associated with a CORESET, and each CORESET configuration can be associated with one or more SS sets.

[0093] -searchSpaceId: This parameter / information indicates the ID of the SS collection.

[0094] -controlResourceSetId: This parameter / information indicates the CORESET associated with the SS collection.

[0095] -monitoringSlotPeriodicityAndOffset: This parameter / information indicates the PDCCH monitoring period (in slots) and the PDCCH monitoring offset (in slots).

[0096] -monitoringSymbolsWithinSlot: This parameter / information indicates the first OFDMA symbol used for PDCCH monitoring in the slot in which PDCCH monitoring is configured. The first OFDMA symbol is indicated by a bitmap, and each bit corresponds to each OFDMA symbol in the slot. The MSB of the bitmap corresponds to the first OFDMA symbol in the slot. The OFDMA symbol corresponding to the bit with a value of 1 corresponds to the first symbol in the CORESET of the slot.

[0097] -nrofCandidates: This parameter / information indicates the number of PDCCH candidates for each AL (where AL = {1, 2, 4, 8, 16}) (e.g., one of 0, 1, 2, 3, 4, 5, 6, and 8).

[0098] -searchSpaceType: This parameter / information indicates whether the SS type is CSS or USS.

[0099] -DCI format: This parameter / information indicates the DCI format of the PDCCH candidate.

[0100] The UE can monitor PDCCH candidates in one or more SS sets within a time slot, based on the configuration of the CORESET / SS sets. The timing of monitoring PDCCH candidates (e.g., time / frequency resources) is defined as the PDCCH (monitoring) timing. One or more PDCCH (monitoring) timings can be configured within a time slot.

[0101] UL physical channel / signal

[0102] (1)PUSCH

[0103] The PUSCH can carry UL data (e.g., Uplink Shared Channel (UL-SCH) transport block (TB)) and / or Uplink Control Information (UCI). The PUSCH can be transmitted based on a Cyclic Prefix Orthogonal Frequency Division Multiplexing (CP-OFDM) waveform or a Discrete Fourier Transform Extended OFDM (DFT-s-OFDM) waveform. When the PUSCH is transmitted based on a DFT-s-OFDM waveform, the UE can transmit the PUSCH by applying transform precoding. For example, when transform precoding is not allowed (e.g., when transform precoding is disabled), the UE can transmit the PUSCH based on a CP-OFDM waveform. When transform precoding is allowed (e.g., when transform precoding is enabled), the UE can transmit the PUSCH based on either a CP-OFDM waveform or a DFT-s-OFDM waveform. PUSCH transmissions can be dynamically scheduled by the PDCCH (dynamic scheduling) or semi-statically scheduled by higher-layer signaling (e.g., RRC signaling) (and / or Layer 1 (L1) signaling (e.g., PDCCH)) (Configured Scheduling (CS)). Therefore, in dynamic scheduling, PUSCH transmissions can be associated with the PDCCH, while in CS, PUSCH transmissions may not be associated with the PDCCH. CS can include PUSCH transmissions based on Type 1 Configuration Certification (CG) and PUSCH transmissions based on Type 2 CG. For Type 1 CG, all parameters for PUSCH transmissions can be signaled by higher layers. For Type 2 CG, some parameters for PUSCH transmissions can be signaled by higher layers, while the rest can be signaled via the PDCCH. Essentially, in CS, PUSCH transmissions may not be associated with the PDCCH.

[0104] (2)PUCCH

[0105] PUCCH can carry UCI. UCI includes the following information.

[0106] - Scheduling Request (SR): SR is information used to request UL-SCH resources.

[0107] - Hybrid Automatic Repeat Request Acknowledgment (HARQ-ACK): HARQ-ACK is a received signal in response to DL signals (e.g., PDSCH, SPS release PDCCH, etc.). HARQ-ACK responses can include affirmative ACK (ACK), negative ACK (NACK), DTX (discontinuous transmission), or NACK / DTX. HARQ-ACK can be used interchangeably with A / N, ACK / NACK, and HARQ-ACK / NACK. HARQ-ACK can be generated based on TB / CBG.

[0108] - Channel State Information (CSI): CSI is feedback information about the DL channel. CSI includes Channel Quality Indicator (CQI), Rank Indicator (RI), Precoding Matrix Indicator (PMI), Precoding Type Indicator (PTI), etc.

[0109] Table 7 shows the PUCCH formats. PUCCH formats can be classified according to UCI payload size / transmission length (e.g., the number of symbols included in the PUCCH resource) and / or transmission structure. PUCCH formats can be classified according to transmission length into short PUCCH formats (PUCCH formats 0 and 2) and long PUCCH formats (PUCCH formats 1, 3, and 4).

[0110] [Table 7]

[0111]

[0112] (0) PUCCH format 0 (PF0)

[0113] - Supported UCI payload size: up to K bits (e.g., K=2)

[0114] - Number of OFDM symbols included in a PUCCH: 1 to X symbols (e.g., X = 2)

[0115] - Transmission structure: Only the UCI signal is configured without DM-RS. The UCI status is transmitted by selecting and sending one of multiple sequences.

[0116] (1) PUCCH Format 1 (PF1)

[0117] - Supported UCI payload size: up to K bits (e.g., K=2)

[0118] - Number of OFDM symbols included in a PUCCH: Y to Z symbols (e.g., Y = 4 and Z = 14)

[0119] - Transmission Structure: UCI and DM-RS are configured in different OFDM symbols based on Time Division Multiplexing (TDM). For UCI, a specific sequence is multiplied with a modulation symbol (e.g., a QPSK symbol). Cyclic shift / orthogonal overlay codes (CS / OCC) are applied to both UCI and DM-RS to support code division multiplexing (CDM) between multiple PUCCH resources (compliant with PUCCH format 1) (within the same RB).

[0120] (2) PUCCH Format 2 (PF2)

[0121] - Supported UCI payload size: exceeding K bits (e.g., K=2)

[0122] - Number of OFDM symbols included in a PUCCH: 1 to X symbols (e.g., X = 2)

[0123] - Transmission structure: UCI and DMRS (DM-RS) are configured / mapped to the same symbol based on frequency division multiplexing (FDM), and the encoded UCI bits are transmitted by applying only the inverse fast Fourier transform (IFFT) to it without the DFT.

[0124] (3) PUCCH Format 3 (PF3)

[0125] - Supported UCI payload size: exceeding K bits (e.g., K=2)

[0126] - Number of OFDM symbols included in a PUCCH: Y to Z symbols (e.g., Y=4 and Z=14)

[0127] - Transmission Structure: UCI and DMRS are configured / mapped to different symbols based on TDM. Encoded UCI bits are transmitted by applying DFT to them. To support multiplexing among multiple UEs, OCC is applied to UCI, and CS (or Interleaved Frequency Division Multiplexing (IFDM) mapping) is applied to DM-RS before DFT.

[0128] (4) PUCCH format 4 (PF4)

[0129] - Supported UCI payload size: exceeding K bits (e.g., K=2)

[0130] - Number of OFDM symbols included in a PUCCH: Y to Z symbols (e.g., Y=4 and Z=14)

[0131] -Transmission Structure: UCI and DMRS are configured / mapped to different symbols based on TDM. DFT is applied to the encoded UCI bits, without multiplexing between UEs.

[0132] Figure 4This illustrates the ACK / NACK transmission process. (Refer to...) Figure 4 The UE can detect the PDCCH in time slot #n. The PDCCH includes DL scheduling information (e.g., DCI format 1_0 or DCI format 1_1). The PDCCH indicates the DL assignment offset K0 to the PDSCH and the PDSCH to the HARQ-ACK reporting offset K1. For example, DCI format 1_0 or DCI format 1_1 may include the following information.

[0133] - Frequency domain resource assignment: Indicates the set of RBs assigned to the PDSCH.

[0134] - Time-domain resource assignment: Indicates the starting position (e.g., OFDM symbol index) and length (e.g., number of OFDM symbols) of K0 and the PDSCH in the time slot.

[0135] –PDSCH to HARQ_feedback timer indicator: Indicates K1.

[0136] After receiving a PDSCH in time slot #(n+K0) according to the scheduling information of time slot #n, the UE can transmit a UCI on the PUCCH in time slot #(n+K1). The UCI includes a HARQ-ACK response to the PDSCH. When the PDSCH is configured to carry a maximum of one TB, the HARQ-ACK response can be configured in one bit. When the PDSCH is configured to carry at most two TBs, the HARQ-ACK response can be configured in two bits if spatial binding is not configured, and in one bit if spatial binding is configured. When time slot #(n+K1) is designated as the timing for HARQ-ACK transmission of multiple PDSCHs, the UCI transmitted in time slot #(n+K1) includes HARQ-ACK responses to multiple PDSCHs.

[0137] Figure 5 An exemplary PUSCH transmission process is shown. (Reference) Figure 5 The UE can detect the PDCCH in time slot #n. The PDCCH may include UL scheduling information (e.g., DCI format 0_0 or DCI format 0_1). DCI format 0_0 and DCI format 0_1 ​​may include the following information.

[0138] - Frequency domain resource assignment: Indicates the set of RBs allocated to PUSCH.

[0139] - Time-domain resource assignment: Specifies the time slot offset K2, which indicates the starting position (e.g., symbol index) and length (e.g., number of OFDM symbols) of the PUSCH in the time slot. The starting symbol and length of the PUSCH can be indicated by the start and length indicator value (SLIV) or separately.

[0140] Then, the UE can send the PUSCH in time slot #(n+K2) according to the scheduling information in time slot #n. The PUSCH includes the UL-SCH TB.

[0141] 1. Wireless communication systems for supporting non-terrestrial networks (NTN)

[0142] Non-terrestrial networks (NTNs) refer to networks or segments configured to use radio resources in satellite or unmanned aerial vehicle (UAS) systems platforms.

[0143] To ensure wider coverage or provide wireless communication services in areas where it is difficult to install wireless communication base stations (BSs), the use of non-terrestrial networks (NR NTN) or LTE NTN services has been considered. NR or LTE services, as existing terrestrial network (TN) services, provide wireless communication services to UEs by installing corresponding BSs on the ground. However, NTN services provide wireless communication services to UEs by installing BSs in locations not placed on the ground, such as satellites (geostationary orbit, low Earth orbit, medium Earth orbit, etc.), aircraft, drones, etc.

[0144] Figure 6 An example of a scenario in which the UE can access the NTN is shown. Figure 6 (a) shows an example of an NTN scenario based on a transparent payload, and Figure 6 (b) shows an example of an NTN scenario based on regenerated payload.

[0145] NTN can typically be characterized by the following factors.

[0146] - One or more SAT gateways for connecting the NTN to the public data network:

[0147] Geostationary Earth Orbit (GEO) satellites can be provided from one or more SAT gateways located within a coverage area targeted by satellites (e.g., regional or even continental coverage). It can be assumed that a UE within a cell is served by only one SAT gateway.

[0148] Non-GEO satellites can be continuously served by one or more GAT gateways. The system can ensure service and feeder link continuity between serving SAT gateways for a period of time sufficient for mobility anchoring and handover.

[0149] - Feeder link or wireless link between the SAT gateway and the satellite (or UAS platform)

[0150] -Service link or radio link between UE and satellite (or UAS platform)

[0151] - A satellite (or UAS platform) used to implement one of the transparent or regenerative (including airborne processing) payloads. The satellite (or UAS platform) can typically generate multiple beams within a service area defined by the satellite's (or UAS platform's) field of view. The coverage area (footprint) of the beams can be approximately elliptical. The field of view of the satellite (or UAS platform) can be determined based on the airborne antenna diagram and minimum elevation angle.

[0152] Transparent payload: RF filtering, as well as frequency conversion and amplification. Therefore, the waveform signal repeated by the payload is not altered.

[0153] Regenerated payload: demodulation / decoding, switching and / or routing, encoding / modulation, RF filtering, frequency conversion, and amplification. This is practically equivalent to having all or some of the functions of a BS (e.g., gNB) on a satellite (or UAS platform).

[0154] - Inter-satellite links (ISL) in the case of satellite groups. For this, satellites need to regenerate payloads. ISLs can operate at RF frequencies or broadband.

[0155] - The UE can be served by satellites (or UAS platforms) within the target service area.

[0156] Table 8 below shows examples of satellite (or UAS platform) types.

[0157] [Table 8]

[0158]

[0159] generally,

[0160] GEO satellites and UAS can be used to provide services to the continent, region, or local area.

[0161] • Low Earth Orbit (LEO) and Medium Earth Orbit (MEO) constellations can be used to provide service in both the Northern and Southern Hemispheres. In some cases, the constellation can also provide global coverage, including polar regions. Later, appropriate orbital inclination, sufficient generated beams, and inter-satellite links may be required.

[0162] Highly elliptical orbit (HEO) satellite systems could also be considered.

[0163] The following text describes wireless communication systems in NTN, including the following six reference scenarios.

[0164] • Circular track and nominal station holding platform

[0165] Maximum Round-Trip Delay (RTD) Constraint

[0166] • Maximum Doppler constraint

[0167] • Transparent or regenerable payload

[0168] • One scenario with ISL and one scenario without ISL. In the case of inter-satellite links, payload regeneration may be required.

[0169] • Fixed or steerable beams that create mobile or fixed coverage areas on the ground. Six reference scenarios are considered in Tables 9 and 10.

[0170] [Table 9]

[0171] Transparent Satellite Regenerated Satellite GEO-based non-terrestrial access network Scenario A Scene B LEO-based non-terrestrial access networks: steerable beams Scene C1 Scene D1 LEO-based non-terrestrial access networks: Beams move with satellites Scene C2 Scene D2

[0172] [Table 10]

[0173]

[0174]

[0175] Reference 1: Each satellite can use beamforming technology to direct its beam to a fixed point on Earth. This can be applied to the time corresponding to the satellite's visibility.

[0176] Reference 2: The maximum delay variation in the beam (UE fixed on the ground) can be calculated based on the minimum elevation angle of both the gateway and the UE.

[0177] Reference 3: The maximum differential delay in the beam can be calculated based on the diameter of the maximum beam coverage area at the lowest point (at the lowest point).

[0178] Reference 4: The speed of light used to calculate the delay can be 299,792,458 m / s.

[0179] Reference 5: Assuming there is a spot beam at the edge of the coverage area (low altitude), the size of the maximum beam coverage area of ​​the GEO can be determined based on the current state of the GEO high throughput system technology.

[0180] Reference 6: The beam-level delay of the largest beam size can be considered to calculate the maximum differential delay at the cell level. When the beam size is small or medium, a cell may include two or more beams. However, the cumulative differential delay of all beams in a cell may not exceed the maximum differential delay at the cell level in Table 10.

[0181] The NTN-related descriptions in this manual can be applied to NTN GEO scenarios and any non-Geostationary Orbit (NGSO) scenario with a circular orbit at an altitude of 600 km or greater.

[0182] 2. Random Access Procedure

[0183] Figure 7 The random access procedure is shown. Figure 7 (a) illustrates a contention-based random access procedure, and Figure 7 (b) illustrates the dedicated random access procedure.

[0184] refer to Figure 7 (a) The contention-based random access procedure comprises the following four steps. The messages sent in steps 1 to 4 can be referred to as message 1 (Msg1) to message 4 (Msg4), respectively.

[0185] - Step 1: The UE sends the RACH preamble on the PRACH.

[0186] - Step 2: The UE receives a random access response (RAR) from the BS on the DL-SCH.

[0187] - Step 3: The UE sends Layer 2 (L2) / Layer 3 (L3) messages to the BS on the UL-SCH.

[0188] - Step 4: The UE receives the contention resolution message from the BS on the DL-SCH.

[0189] The UE can receive random access information from the system information in the BS.

[0190] When a UE requires random access, the UE sends a RACH preamble to the BS as in step 1. The BS can identify each RACH preamble by the time / frequency resources (RACH timing (RO)) and preamble index (PI) in which it sends the RACH preamble.

[0191] Upon receiving a RACH preamble from the UE, the BS sends a RAR message to the UE as described in step 2. To receive the RAR message, the UE monitors the L1 / L2 PDCCH with Cyclic Redundancy Check (CRC) masked using a Random Access RNTI (RA-RNTI) within a pre-configured time window (e.g., ra-ResponseWindow), which includes scheduling information for the RAR message. The RA-RNTI-masked PDCCH can be sent only within the common search space. When a scheduling signal masked using RA-RNTI is received, the UE can receive the RAR message on the PDSCH indicated by the scheduling information. The UE then checks whether RAR information pointing to the UE exists in the RAR message. The presence or absence of RAR information pointing to the UE can be determined by checking for the presence of a Random Access Preamble ID (RAPID) used for the preamble sent by the UE. The index of the preamble sent by the UE can be the same as the RAPID. RAR information includes the index corresponding to the RACH preamble, timing offset information for UL synchronization (e.g., timing advance command (TAC)), UL scheduling information for Msg3 transmission (e.g., UL permission), and UE temporary identification information (e.g., temporary C-RNTI (TC-RNTI)).

[0192] Upon receiving RAR information, the UE transmits UL-SCH data (Msg3) on the PUSCH based on the UL scheduling information and timing offset value, as described in step 3. Msg3 may include the UE's ID (or global ID). Alternatively, Msg3 may include RRC connection request information for initial access (e.g., an RRCSetupRequest message). Additionally, Msg3 may include a buffer status report (BSR) regarding the amount of data available for transmission at the UE.

[0193] After receiving the UL-SCH data, the BS sends a contention resolution message (Msg4) to the UE, as described in step 4. When the UE receives the contention resolution message and the contention is successfully resolved, the TC-RNTI is changed to the C-RNTI. Msg4 may include the UE's ID and / or RRC connection-related information (e.g., an RRCSetup message). If the information sent in Msg3 does not match the information received in Msg4, or if the UE does not receive Msg4 within a predetermined time, the UE can retransmit Msg3 to confirm that the contention resolution has failed.

[0194] refer to Figure 7(b) The Dedicated Random Access Procedure comprises the following three steps. The messages sent in steps 0 to 2 may be referred to as Msg0 to Msg2, respectively. The BS may trigger the Dedicated Random Access Procedure via the PDCCH, which serves the purpose of commanding the RACH preamble transmission (hereinafter referred to as the PDCCH command).

[0195] - Step 0: The BS allocates a RACH preamble to the UE via dedicated signaling.

[0196] - Step 1: The UE sends the RACH preamble on the PRACH.

[0197] - Step 2: The UE receives the RAR from the BS on the DL-SCH.

[0198] Steps 1 and 2 of the dedicated random access procedure can be the same as steps 1 and 2 of the contention-based random access procedure.

[0199] In NR, DCI format 1_0 is used to initiate a contention-free random access procedure via PDCCH commands. DCI format 1_0 is used to schedule PDSCH within a DL cell. When the CRC of DCI format 1_0 is scrambled with C-RNTI and all bits of the "Frequency Domain Resource Assignment" field are 1, DCI format 1_0 is used as a PDCCH command to indicate the random access procedure. In this case, the fields of DCI format 1_0 are configured as follows.

[0200] -RA leading index: 6 bits

[0201] -UL / Supplementary UL (SUL) indicator: 1 bit. The UL / SUL indicator indicates the UL carrier in which PRACH is transmitted in the cell when all bits of the RA preamble index are non-zero and SUL is configured for the UE in the cell. Otherwise, it is reserved.

[0202] -SSB (Synchronization Signal / Physical Broadcast Channel) Index: 6 bits. When all bits of the RA preamble index are non-zero, the SSB indicator indicates the SSB used to determine the timing of the RACH transmission for PRACH. Otherwise, it is reserved.

[0203] -PRACH Masking Index: 4 bits. When all bits of the RA leading index are non-zero, the PRACH masking index indicates the timing of the RACH associated with the SSB indicated by the SSB index. Otherwise, it is reserved.

[0204] - Reserved: 10 bits

[0205] When DCI format 1_0 does not correspond to a PDCCH command, DCI format 1_0 includes fields for scheduling PDSCH (e.g., time domain resource assignment, modulation and compilation scheme (MCS), HARQ procedure number, PDSCH to HARQ_feedback timing indicator, etc.).

[0206] 2-step random access process

[0207] In existing technologies, random access is performed through a four-step process as described above. In conventional LTE systems, this four-step random access process takes an average of 15.5ms.

[0208] [Table 11]

[0209]

[0210] NR systems may require lower latency than conventional systems. When random access occurs in the U-band, random access can be terminated only if the UE and BS successfully perform LBT sequentially in all steps of the 4-step random access procedure, i.e., contention can be resolved. If LBT fails even in one step of the 4-step random access procedure, resource efficiency may decrease and latency may increase. If LBT fails during scheduling / transmission associated with Msg2 or Msg3, resource efficiency may decrease significantly and latency may increase significantly. For random access in the L-band, low latency may be required in various scenarios of NR systems. Therefore, a 2-step random access procedure can also be performed in the L-band.

[0211] like Figure 8 As shown in (a), the 2-step random access procedure may include two steps: the transmission of the UL signal from the UE to the BS (referred to as MsgA) and the transmission of the DL signal from the BS to the UE (referred to as MsgB).

[0212] The following description focuses on the initial access procedure, but the proposed method can also be applied to the random access procedure after the UE and BS establish an RRC connection. Furthermore, as... Figure 8 As shown in (b), the random access preamble and PUSCH portion can be sent together during a non-contention-based random access process.

[0213] Although not shown, the BS can send a PDCCH to the UE for scheduling MsgB, which can be called Msg.BPDCCH.

[0214] 3. Public TA in NTN

[0215] The above content (NR frame structure, NTN system, etc.) can be used in combination with the methods presented in this specification, which will be described later, or can be supplemented when clarifying the technical features of the methods presented in this specification.

[0216] Furthermore, the methods described later relate to uplink (UL) transmission and can be equivalently applied to downlink (DL) signal transmission methods in the aforementioned NR or LTE systems. The technical concepts presented in this specification can be modified or replaced to adapt the terminology, expressions, structures, etc., defined in each system for implementation in the respective system.

[0217] The frequency bands considered for use in NR NTN services are mainly the 2GHz band (S band: 2-4GHz) in the 6GHz or lower band, and the DL 20GHz and UL 30GHz bands (Ka band: 26.5-40GHz) in the 6GHz or higher band.

[0218] Table 10 discloses the maximum round-trip latency for each scenario.

[0219] As mentioned above, NR NTN services are mainly divided into two schemes. Figure 9 Figure (a) illustrates the regenerated payload scheme. Figure 9 (b) illustrates a transparent payload scheme. A regenerative payload scheme is one where the satellite itself can be used as a base station. A transparent payload scheme is one where the satellite receives the payload from a ground-based base station and transmits the corresponding signals to the UE.

[0220] refer to Figure 9 Depending on the two NTN service schemes, the methods for defining the common TA (i.e., the common TA refers to the common component of the propagation delay shared by all UEs within the coverage area of ​​the same satellite beam / cell). Specifically, in the regenerated payload scheme, the value obtained by calculating the delay of the serving link is included in the common TA. In the transparent payload scheme, the value calculated by calculating the delay of the feeder link, which is included in the serving link, is included in the common TA. The serving link refers to the link between the satellite and the reference point. The feeder link refers to the link between the satellite and the base station located on the ground.

[0221] In this case, consider the following two options regarding TA acquisition.

[0222] Option 1: Utilize the UE's known location and satellite ephemeris to autonomously obtain the TA at the UE's location.

[0223] Option 2: Timing Advance (TA) Adjustment Based on Network Indication

[0224] Option 1 refers to a method in which the UE knows the satellite's orbit and position, the UE's own position, etc., and compensates for the full TA (i.e., common TA + UE-specific differential TA) based on known values, or the common TA is indicated by the base station and only the UE-specific TA is compensated.

[0225] Option 2 refers to receiving an indication of a common TA from the base station, performing a RACH procedure based on the indicated common TA, and receiving a UE-specific differential TA through the TA command field of the RAR MAC CE.

[0226] The two options mentioned above include a method where the base station instructs the public TA. The following sections describe the operations required for the base station to signal the public TA, the operations for the UE to receive the public TA, and specific methods for signaling the public TA.

[0227] Figure 10 An example of a common TA is shown. In this specification, a common TA refers to the TA applied between a satellite and a reference point. Reference Figure 10 The reference point (RP) is located between the base station and the satellite, i.e., in the feeder link. A reference point existing between the base station and the satellite can be commonly applied to one or more UEs connected to the satellite. Similarly, a common reference point (TA) can be commonly applied to one or more UEs communicating with the corresponding satellite between the reference point and the satellite. The TA applied between the satellite and the UE can be referred to as a UE-specific TA.

[0228] 3.1.gNB Public TA Signaling

[0229] When the base station sends a signal to the UE to notify the public TA, the following methods can be considered.

[0230] [Method 1: Method of indicating multiple public TA series by base station]

[0231] In geostationary satellites, the base station appears stationary from the perspective of the UE on the ground. Therefore, it can be determined that the common TA (Transmission Time) does not change. However, satellites located at lower altitudes than geostationary satellites (e.g., low Earth orbit such as LEO) may not have long available service times due to their faster orbital velocities. Available service time can be the time provided to the UE by the satellite acting as the base station. Based on LEO, the available service time is 15 to 20 minutes, which can be very short depending on the satellite velocity. Since the base station (e.g., the satellite, etc.) appears to be moving at a very high speed from the perspective of the UE on the ground, where the UE receives NTN service from the corresponding satellite, continuing to use the common TA value indicated by the base station at a specific timing point may be unreasonable.

[0232] To address this issue, when a base station notifies a UE of common TA values, it can deliver multiple common TA values ​​defined according to specific rules (e.g., defined based on time flow). Typically, a base station operating in a transparent payload scheme can predetermine when a feeder link will change, calculate multiple common TA values ​​reflecting the changed feeder link's TA values, and send the calculated TA values ​​to the UE. This series of common TA values ​​can be notified to the UE by the base station via higher-layer signaling (e.g., SIB, dedicated RRC signaling) and / or a group common DCI shared by the cell or UE group (e.g., DCI format 2_x series, etc.).

[0233] As an example of multiple common TA values ​​defined according to a time flow, assume a low-Earth orbit (LEO) satellite provides service to the UE for 20 minutes. The base station can calculate the common TA value for the corresponding satellite for 20 minutes every X seconds (e.g., X = 1 or 0.5) to configure a common TA series including multiple TA values ​​and notify the UE of the configured common TA series. Alternatively, the UE can calculate the common TA series during the signaling reconfiguration duration (e.g., SIB reconfiguration time) and notify the UE of the calculated common TA series.

[0234] Additionally, when a base station indicates a common TA, it can notify the UE of the common TA for each beam. Therefore, common TA values ​​can be indicated separately for different common TA families used for multiple beams. Typically, in the SIB, a representative common TA value is indicated for each beam during the SIB reconfiguration period. The base station can indicate the common TA family to UEs and / or UE groups that have entered connected mode via dedicated RRC signaling, UE group common DCI, etc.

[0235] Additionally, as a method for indicating multiple common common TAs (CTs), a representative common TA value can be indicated, and a delta TA value, representing the change of the common TA value over time, can also be indicated. For example, a representative common TA for a specific time period (e.g., SIB reconfiguration time) can be provided using a value calculated based on an initial timing, and a delta TA value, which is the change in common TA every x ms or y us, can also be indicated. Upon receiving this, the UE can determine the common TA value at a specific timing point by adding the delta TA*x (ms) or delta TA*y (us) to the representative common TA value (i.e., by correcting for (time in delta * common TA)). The UE can then perform UL transmission (e.g., RACH procedure) based on the determined common TA value. Furthermore, the base station indicates the representative common TA value, and the UE can update the common TA using functions of the base station's (i.e., satellite's) trajectory, speed, position, etc.

[0236] Additionally, the base station can notify the UE of only a representative common TA as the common TA value, and can indicate a UE-specific differential TA value via RAR-permitted TA commands. This configuration offers the advantage of reducing the payload that the base station needs to include in higher-layer signaling. In this case, during existing RACH procedure operation, the step size in the RAR-permitted TA command can be increased, or negative values ​​and positive values ​​in the TA command may need to be set.

[0237] [Method 2: Using a common TA value as a pre-known value between the base station and the UE]

[0238] Meanwhile, if the UE's autonomous acquisition of TA is defined as the basic operation as in Method 1, low-cost UEs may not support the corresponding autonomous acquisition capability. The base station can configure UEs without autonomous acquisition capability not to access the corresponding cell, but in terms of network operation, it may be desirable to support low-cost UEs to provide NTN services.

[0239] A UE that has not yet acquired a public TA can send a PRACH preamble with the initial TA value set to 0. However, due to the nature of NTN systems with large round-trip delays, if the initial TA value is set to 0 and the RACH procedure is performed, the RAR window and the Random Access Radio Network Temporary Identifier (RA-RNTI) values ​​may not operate with their currently defined values.

[0240] Accordingly, for UEs that do not have autonomous acquisition capabilities, a default common TA value and / or a minimum common TA value can be predefined between the base station and the UE. For example, the default common TA value and / or minimum common TA value can be predefined between the UE and the base station based on the satellite's orbit, altitude, speed, etc. Additionally, the default common TA value and / or minimum common TA value can be predefined between the UE and the base station depending on the satellite type (e.g., LEO, HEO, etc.), the frequency band used by the satellite, etc.

[0241] The UE can perform initial access using a predefined default common TA value and / or a predefined minimum common TA value. When the UE sends a PRACH preamble using the default common TA value and / or the minimum common TA value, the base station can receive the corresponding preamble, send its corresponding RAR, and indicate an additional TA value to the UE through the TA command field in the RAR.

[0242] Currently, the ability of a base station to indicate / configure a common transfer condition (CT) to compensate for round-trip delay between a reference point and a satellite is being discussed. Methods for the UE to track changes in the CT over time have not yet been discussed. Below, methods for updating the CT in consideration of changes over time, and methods for overriding the CT value when updated via two or more channels / signaling, are proposed.

[0243] [Method 3: Public TA Update and Overwrite Method]

[0244] Method 3-1: Public TA Update

[0245] The proposed method 3-1-1: the common TA and / or TA drift rate can be configured to be updated for each predefined period.

[0246] For example, if the common TA and / or TA drift rate is indicated by SIB1, the common TA and / or TA drift rate can be updated for each SIB1 reconfiguration cycle.

[0247] In this case, the reference time for the common TA can be predefined. For example, the reference time for the common TA can be configured to coincide with the start timing point of the SIB1 reconfiguration cycle.

[0248] As another example, the common TA and / or drift rate can be instructed and / or configured to be updated in the same manner as the satellite's ephemeris update cycle. For example, the reference time of the common TA can be configured to coincide with the start point of the satellite's ephemeris update cycle.

[0249] If the above method is expressed mathematically, it can be shown in the following example.

[0250] -Current_common_TA = past_common_TA + drift rate * duration

[0251] In this case, past_common_TA is the most recently updated public TA. Additionally, the duration is the interval between the reference time of past_common_TA and the current reference time.

[0252] The proposed method 3-1-2: In this method, the common TA and TA drift rate are indicated, and the reference timestamp of the common TA is additionally indicated.

[0253] For example, the common TA and / or TA drift rate are indicated via SIB-x and / or RRC signaling and / or MAC-CE, and additionally, the reference timestamp of the common TA is indicated. In this case, the common TA, TA drift rate, and / or reference timestamp are updated via new signaling indicated from the base station (e.g., SIB-x and / or RRC signaling and / or MAC-CE).

[0254] For example, the common TA and / or TA drift rate can be indicated via SIB1, and a reference timestamp for the common TA can also be indicated. In this case, the common TA, TA drift rate, and / or reference timestamp are updated for each SIB1 reconfiguration cycle.

[0255] Method 3-2. Common TA and / or TA drift rate coverage

[0256] When the base station is able to notify the UE of the common TA and / or TA drift rate through SIB1 and / or SIB-x and / or RRC signaling and / or MAC-CE, the UE can override the parameters through the following operations.

[0257] For example, if the common TA and / or TA drift rate are sent from the base station via SIB1, and the common TA and / or MAC-CE are later updated via RRC signaling (or SIB-x and / or MAC-CE), the UE (by ignoring the common TA and / or TA drift rate obtained via SIB1) uses the updated value via RRC signaling (or SIB-x and / or MAC-CE) to track the common TA. In this case, the base station can provide an update cycle for the common TA and / or TA drift rate in advance. If the common TA and / or TA drift rate is not updated according to the update cycle provided by the base station, the UE determines that the current common TA and / or TA drift rate is no longer valid and is configured to reuse the common TA and / or TA drift rate value from SIB1. Alternatively, the UE determines that the current common TA and / or TA drift rate does not require further updates and is configured to continue using the current common TA and / or TA drift rate value.

[0258] For example, if the common TA and / or TA drift rate are sent from the base station via SIB1, and the common TA and / or TA drift rate are not updated via RRC signaling (or SIB-x and / or MAC-CE), the UE is configured to check for the presence or absence of an update to the common TA and / or TA drift rate during each SIB1 reconfiguration cycle and apply it.

[0259] Typically, when a UE entering connected mode receives an update to the common TA and / or TA drift rate via UE-specific RRC signaling, the following UE actions may be required. For example, if a contention-based RACH (CBRA) is needed (e.g., when a RACH procedure based on a PDCCH command is indicated via CBRA), the UE can be configured to recalculate the TA using the common TA and / or TA drift rate values ​​indicated via SIB1. The UE can then use the calculated TA value to send a PRACH preamble. Alternatively, if a contention-free RACH (CFRA) is needed (e.g., when a RACH procedure based on a PDCCH command is indicated via CFRA), the UE can be configured to calculate the TA as is using the common TA and / or TA drift rate updated via existing UE-specific RRC signaling. The UE can then use the calculated TA value to send a PRACH preamble.

[0260] Although the proposed method has been described based on the serving satellite, the same method can be applied to the target satellite during handover and / or service satellite changes. Additionally, the common TA and / or TA drift rate for the target satellite (the upcoming satellite) can be configured and / or indicated separately from the values ​​corresponding to the serving satellite, during handover and / or service satellite changes.

[0261] 3.2. A method for a base station to configure RO for a UE that has failed to obtain a public TA.

[0262] Even assuming the base station does not transmit the common TA and the UE can autonomously acquire the common TA, low-cost UEs may not support autonomous acquisition capability. If so, some UEs can acquire the common TA, while others cannot. Therefore, in this case, the base station can use the following method to configure the RO to effectively manage the RACH slots.

[0263] A UE that fails to acquire a public TA can set the initial TA value to 0 and send a PRACH preamble. The UE can also use the initial TA value as the default TA value to send a PRACH preamble, as shown in Method 2. The initial TA refers to the value set by the UE performing the RACH procedure. The default TA value refers to a specific value pre-configured as the initial TA value for RACH procedures, etc., between the base station and the UE.

[0264] [Method 4: A method for a base station to separately indicate RO to a UE that has failed to obtain a public TA via a PRACH configuration (or implicitly) independent of the existing PRACH configuration]

[0265] Method 4 involves a UE that has already acquired a public TA selecting one or more ROs from the existing PRACH configuration to send the PRACH preamble, and a UE that has failed to acquire a public TA selecting one or more ROs from the separately indicated PRACH configuration to send the PRACH preamble. UEs that have already acquired a public TA can be configured to ignore separately indicated PRACH configurations (or invalid ROs).

[0266] Meanwhile, a standalone PRACH configuration can be used to indicate the RO for a UE that failed to acquire a public TA. However, the RO for a UE that failed to acquire a public TA can be defined to be multiplexed with the RO specified through an existing PRACH configuration (e.g., by FDM or by TDM). Considering the case of FDM, the base station needs to indicate the RO FDM value of the existing PRACH configuration as a value excluding the maximum value in order to maintain and use the currently defined RA-RNTI value. For example, the current RO FDM value can indicate 1, 2, 4, or 8, therefore the maximum value of 8 is not indicated.

[0267] Additionally, the base station can be configured to indicate to the UE, via TDM and / or FDM with existing ROs, whether there are g ROs for a UE that failed to acquire a public TA. In this case, (for a base station serving all UEs) the value of g can be defined as an integer of 1 or greater. The UE can use the indicated value to determine which specified RO is the RO for the UE that failed to acquire a public TA.

[0268] For example, if the RO indicated by the base station is configured to be FDMed up to k (e.g., k=4), and the existence of g ROs (e.g., g=2) for a UE that failed to acquire a common TA is indicated by FDMing with existing ROs, then the UE that failed to acquire a common TA can be configured to send a PRACH preamble by selecting one of the (k+1)th (e.g., the 5th) RO and the (k+2)th (e.g., the 6th) RO in the corresponding RACH slot at a lower frequency order.

[0269] According to method 4, in ROs indicated by the existing PRACH configuration, the existing RACH procedure can be maintained since only UEs that have acquired a common TA can send a PRACH preamble. However, in additionally indicated ROs (i.e., ROs where UEs that have failed to acquire a common TA send a PRACH preamble), since UEs that have failed to acquire a common TA send a PRACH preamble, additional RAR windows and / or RA-RNTI values ​​may be required, or gaps between ROs or between RAR windows may be needed.

[0270] [Method 5: Configuring a UE that fails to obtain a public TA to send a PRACH preamble by specifying one or more ROs among one or more ROs indicated by an existing PRACH configuration]

[0271] According to the configuration of Method 1, there are the following advantages: the base station does not need to perform additional operations on UEs that have already obtained a public TA, but there is an overhead of configuring additional ROs for UEs that have failed to obtain a public TA. Therefore, by selecting one or more ROs from a plurality of predefined ROs, UEs that have failed to obtain a public TA can be configured to send a PRACH preamble through the selected RO.

[0272] For example, if an RO is selected for a UE that has failed to acquire a public TA, the lowest (or highest) RO index, the RO at the lowest (or highest) frequency, the RO at the first (or last) timing, etc., can be selected from predefined ROs. Alternatively, a specific RACH slot can be specified for the UE that has failed to acquire a public TA.

[0273] According to method 5, in a specific RO, UEs that have acquired a common TA and UEs that have not acquired a common TA can coexist. For example, if a UE that has not acquired a common TA sends a PRACH preamble by setting the initial TA value to 0, a UE that has acquired a common TA can configure a RAR window and monitor RAR by determining a timing point where the RAR window becomes two (or three) times the common TA after sending Msg.1. Additionally, since the base station should receive the PRACH preamble from UEs that have not acquired a common TA, the PRACH preamble reception period needs to be configured to be longer than the common TA. UEs that have not acquired a common TA send Msg.1 by setting the initial TA value to 0 and then directly monitor the RAR window. In doing so, due to propagation delay, RAR can be sent at least twice the common TA. Therefore, in this case, the RAR window needs to be configured to be large for UEs that have not acquired a common TA.

[0274] To address the aforementioned issues, as shown in Method 2, UEs that fail to acquire a common TA can set the default TA value to the initial TA value and send Msg.1. Furthermore, by determining that the RAR window starts at a time point twice the default TA, UEs that fail to acquire a common TA can configure the RAR window and monitor RAR. According to this configuration, from the base station's perspective, there is an advantage in not needing to configure a long interval for receiving the PRACH preamble. Since the TA difference between UEs that have acquired a common TA and UEs using the default TA may not be significant, the size of the RAR window may not be configured as large as in the example above.

[0275] 3.3. Operation of base stations and UEs in systems configured to use public TA

[0276] - SSB to RO mapping related operations when using public TA

[0277] Basically, a common TA can be indicated for each beam. Therefore, when multiple SSBs with different indices are transmitted over different beams, and if the SSB-to-RO mapping is set to 1 to N (where N≥1), the common TA values ​​between the multiple ROs can be set to be different from each other.

[0278] Meanwhile, when the SSB-to-RO mapping is set to N to 1 (where N ≥ 1), UEs with different common TA values ​​can transmit PRACH preambles in a specific RO. The base station needs to configure the PRACH preamble reception interval based on the smaller of the different common TA values. Additionally, the base station can be configured to notify UEs attempting to transmit PRACH preambles in a specific RO of all common TA values ​​that will be used in the corresponding RO.

[0279] Typically, the maximum common TA (or maximum K offset) value used within the same RO can be applied by all UEs that have already transmitted a PRACH preamble in the corresponding RO, thereby determining the RAR window start timing. The K offset is applied only when a RAR is received. When transmitting and receiving other DL and / or UL signals / channels, the K offset configured for each common TA defined per SSB beam can be applied.

[0280] Alternatively, since the base station indicates / configures a common TA (or common K offset) value to be used in the same RO, all UEs transmitting a PRACH preamble in the corresponding RO can apply the common TA value to determine the start timing of the RAR window. The common K offset is applied only during RAR reception, and in cases of transmitting and receiving other DL and / or UL signals / channels, the K offset configured for each common TA defined per SSB beam can be applied. Therefore, the K offset can be indicated separately from the K offset configured per SSB (common TA). Furthermore, among the common TA values ​​having in the SSB index mapped to the corresponding RO, the RAR window start point can be calculated based on the maximum common TA value.

[0281] A specific example is described below. Multiple SSB indices (e.g., two SSB indices) are mapped to the same RO. UE 1 and UE 2 respectively assume a common TA value corresponding to different SSB indices as TA. UE1 and TA UE2 UE 1 and UE 2 assume that the K offset values ​​corresponding to different SSB indices are K and K, respectively. UE1 and K UE2 If TA UE2 If the maximum value in the public TA configured for the SSB index mapped to the RO is used, then UE 2 (which has already selected the SSB index corresponding to the corresponding TA) can configure the RAR window to start based on a predefined processing time and / or a timing offset after the timing point from the PRACH preamble transmission. Meanwhile, (if the SSB index corresponding to the TA has already been selected)... UE2 The UE 1 can configure the RAR window to store the totals corresponding to the SSB index of the public TA. (or )or (or The delay begins after adding the predefined processing time from the timing point of sending the PRACH preamble and / or the timing after the processing offset.

[0282] Alternatively, in systems such as NTNs configured to use a common TA, the SSB-to-RO mapping can always be set to 1 to N (N≥1). If so, then in the case of a particular RO, the existing RACH procedure can be used as is because the common TA value corresponding to the same beam is used to transmit the PRACH preamble.

[0283] - A method by which a UE capable of autonomous acquisition utilizes a public TA sent from a base station.

[0284] Even when the UE can autonomously acquire the common TA, the base station can still indicate a common TA value. The UE can use the indicated common TA value as an upper or lower limit to determine whether a directly calculated common TA value is valid. Alternatively, the UE can determine the validity of a directly calculated common TA value by checking whether it is within a predetermined range from the indicated common TA value. For example, if the directly calculated common TA value is a threshold or more smaller than the indicated common TA value, the UE can determine that the directly calculated common TA value is invalid and use the indicated common TA value to send the PRACH preamble.

[0285] - Method for individually indicating the TA value of the feeder link and the service link

[0286] A base station operating with a transparent payload scheme can notify the UE of the common TA values ​​that are divided into feeder link and service link portions. This configuration has the following advantages: when a satellite changes a feeder link, only the TA value corresponding to that feeder link can be updated. Furthermore, if the UE is informed in advance of the feeder link change schedule and the TA values ​​to be applied upon change, the TA values ​​corresponding to the feeder link can be updated according to the timing of the feeder link change, thereby updating the common TA.

[0287] - Methods for using common TA values ​​by obtaining common TA values ​​from K offset values

[0288] A UE that receives an indication of the K offset from a base station can obtain the common TA value from the K offset. For example, a UE can obtain the common TA value using an equation such as "common TA = K offset - UE-specific differential TA (i.e., differential delay)".

[0289] During initial access, the UE uses a default common TA pre-configured between the base station and the UE, or a representative common TA value indicated by the base station. When a K offset value is indicated to a UE that has already entered connected mode, the UE can calculate the common TA value based on the corresponding K offset. Therefore, the calculated common TA can be used for connected mode RACH procedures, etc.

[0290] - A method for obtaining the K offset using information indicated by the base station (e.g., public TA) and / or information obtained by the UE (e.g., UE-specific TA).

[0291] The UE can obtain its position information via the Global Navigation Satellite System (GNSS) and use the satellite's orbital information to calculate the delay between the UE and the satellite (i.e., the UE-specific delay). Subsequently, the base station broadcasts the delay (i.e., the common TA) from a reference point configured by the network (in this case, the reference point is the one used for the UE to match the UL / DL time slot boundaries) to the satellite. The UE can obtain the entire TA value by combining the corresponding common TA value with the UE-specific TA obtained by the UE.

[0292] In the above scenario, the UE can obtain the K offset value based on the common TA value indicated by the base station and / or the UE-specific TA value obtained by the UE. According to this configuration, since the UE-specific TA value obtained by each UE may be slightly different, the K offset values ​​between UEs can be obtained differently. The UE can then report the obtained K offset value (or UE-specific TA value or total TA value) to the base station. In this case, the UE can report the obtained K offset value to the base station via RO index, preamble index, etc. The base station can send confirmation of whether the K offset value (or UE-specific TA value or total TA value) reported by the UE is appropriate via RAR. If the TA value obtained autonomously by the UE is obtained with high probability of accuracy, all 12 bits defined in the current NR system may not be needed in the TA command field of the RAR. Therefore, the TA command field of the RAR can be reduced by N bits (e.g., N=1), and the base station can check whether the K offset value reported by the UE with the corresponding N bits is appropriate. Alternatively, the K offset value reported by the UE with the corresponding N bits can be finely adjusted. The UE can send Msg.3PUSCH based on information sent by the base station.

[0293] - A method of indicating K-offs by classifying them into common K-offs and residual K-offs.

[0294] To reduce base station signaling overhead, K-off can be indicated by classifying it into common K-off and residual K-off. In this case, the base station can transmit the common K-off value via SIB, and the residual K-off value via RAR, UE-specific RRC signal, etc. Furthermore, the common K-off value can be configured to be cell-specific and / or beam-specific.

[0295] Clearly, examples of the methods proposed above can also be included as one of the implementation methods of this specification, and therefore can be considered as a kind of proposed method. Furthermore, the methods proposed above can be implemented independently, but can also be implemented in the form of a combination (or merging) of some proposed methods. Rules can be defined such that the base station notifies the UE via predefined signals (e.g., physical layer signals or higher-layer signals) whether the proposed method (or information about the rules regarding the proposed method) is applied. Higher layers may include one or more functional layers such as MAC, RLC, PDCP, RRC, and SDAP.

[0296] The methods, embodiments, or descriptions used to implement the methods set forth in this specification may be applied individually, or one or more methods (or embodiments or descriptions) may be applied in combination.

[0297] Implementation Examples

[0298] Figure 11 This is a flowchart of a signal transmission / reception method according to an embodiment of the present disclosure.

[0299] refer to Figure 11 Embodiments of the present invention can be executed by a UE and may include a step S1101 of receiving information about a common TA value and a step S1103 of communicating with a base station based on the common TA value. Although not shown, a method executed by a base station may include a step of sending information about a common TA value and a step of communicating with a UE based on the common TA value.

[0300] The UE can obtain a common TA value based on one or more combinations of methods 1 to 5, and communicate with the base station based on the obtained common TA value. The base station can also deliver a common TA value to the UE based on one or more combinations of methods 1 to 5, and communicate with the UE based on the delivered common TA value. In systems using a common TA, the operations of the UE and the base station can be performed through one or more combinations of the operations described in Section 3.3.

[0301] For example, the UE can receive information about multiple common TA values ​​to be used during a specific time interval based on method 1. These multiple common TA values ​​can be referred to as a common TA series. A common TA value refers to a TA value applied between a satellite and a reference point, such as a reference... Figure 10 The common TA value can be applied collectively to UEs connected to the satellite.

[0302] Specifically, information regarding common TA values ​​may include information about N common TA values ​​for a specific time interval divided into N time intervals. For example, a base station may divide a specific time interval into X second units and notify the UE of the common TA values ​​of the N divided time intervals as a common TA series. In this specification, the X value does not necessarily have to be an integer and may be a specific rational number. Alternatively, the X value may match one or more symbols, slots, and / or subframe lengths.

[0303] Alternatively, information about the common TA value can include a representative common TA value and a delta TA value, and the common TA value can be incremented from the representative common TA value by the delta TA value at each configured time interval during a specific time interval. For example, when the base station delivers the representative common TA value and the delta TA value to the UE, the UE initially uses the representative common TA value as the common TA value to be applied to itself. Subsequently, when X seconds have elapsed, the representative common TA value is incremented by the delta TA value, and the incremented value is used as the common TA value. The UE can use the common TA value that is incremented by the delta TA value every X seconds.

[0304] Alternatively, information about the public TA value may include a representative public TA value. Furthermore, the public TA value can be determined by updating the representative public TA value based on the satellite's orbit, velocity, and / or location during a specific time interval. For example, the base station sends information about the representative public TA value to the UE. The UE initially uses the representative public TA value as the public TA value to be applied to itself. The UE can update the representative public TA value every X seconds based on the satellite's orbit, velocity, and / or location, and can use the updated value.

[0305] Information about common TA values ​​can include information about multiple common TA values ​​to be used during a specific time interval for each beam. For example, information about common TA values ​​can include a series of common TA values ​​as many as the number of beams transmitted by the base station. Additionally, information about common TA values ​​can include information indicating which beam each common TA series is mapped to.

[0306] Besides reference Figure 11 In addition to the described operations, refer to Figures 1 to 10 The operations described and / or one or more of the operations described in sections 3.1 to 3.3 may be combined and performed additionally.

[0307] Examples of using the communication system disclosed herein

[0308] The various descriptions, functions, processes, proposals, methods and / or operation flowcharts of this disclosure described herein can be applied to (but are not limited to) various fields where wireless communication / connectivity (e.g., 5G) is required between devices.

[0309] More specific examples will now be described with reference to the accompanying drawings. In the following drawings / descriptions, unless otherwise specified, similar reference numerals denote the same or corresponding hardware blocks, software blocks, or functional blocks.

[0310] Figure 12 A communication system 1 applied to this disclosure is shown.

[0311] Reference Figure 12 The communication system 1 applied to this disclosure includes wireless devices, a network (BS), and a network. Wireless devices are devices that perform communication using radio access technology (RAT) (e.g., 5G NR (or new RAT) or LTE), also referred to as communication / radio / 5G devices. Wireless devices may include (but are not limited to) robots 100a, vehicles 100b-1 and 100b-2, extended reality (XR) devices 100c, handheld devices 100d, home appliances 100e, IoT devices 100f, and artificial intelligence (AI) devices / servers 400. For example, vehicles may include vehicles with wireless communication capabilities, autonomous vehicles, and vehicles capable of vehicle-to-vehicle (V2V) communication. In this document, vehicles may include unmanned aerial vehicles (UAVs) (e.g., drones). XR devices may include augmented reality (AR) / virtual reality (VR) / mixed reality (MR) devices and may be implemented in the form of head-mounted displays (HMDs), head-up displays (HUDs) installed in vehicles, televisions (TVs), smartphones, computers, wearable devices, home appliances, digital signage, vehicles, robots, etc. Handheld devices may include smartphones, smart tablets, wearable devices (e.g., smartwatches or smart glasses), and computers (e.g., laptops). Home appliances may include TVs, refrigerators, washing machines, etc. IoT devices may include sensors, smart meters, etc. For example, the BS and network can be implemented as wireless devices, and a particular wireless device 200a can operate as a BS / network node for other wireless devices.

[0312] Wireless devices 100a to 100f can connect to network 300 via BS 200. AI technology can be applied to wireless devices 100a to 100f, and wireless devices 100a to 100f can connect to AI server 400 via network 300. Network 300 can be configured using a 3G network, a 4G (e.g., LTE) network, or a 5G (e.g., NR) network. Although wireless devices 100a to 100f can communicate with each other via BS 200 / network 300, wireless devices 100a to 100f can also perform direct communication with each other without BS / network intervention (e.g., sidelink communication). For example, vehicles 100b-1 and 100b-2 can perform direct communication (e.g., V2V / Vehicle-to-Everything (V2X) communication). IoT devices (e.g., sensors) can perform direct communication with other IoT devices (e.g., sensors) or other wireless devices 100a to 100f.

[0313] Wireless communication / connections 150a, 150b, and 150c can be established between wireless devices 100a to 100f / BS 200 and between BS 200. In this document, wireless communication / connections can be established via various RATs (e.g., 5G NR) such as UL / DL communication 150a, sidelink communication 150b (or D2D communication), or inter-BS communication (e.g., relay or integrated access backhaul (IAB)). Wireless signals can be transmitted and received between wireless devices, between wireless devices and BSs, and between BSs via wireless communication / connections 150a, 150b, and 150c. For example, signals can be transmitted and received via various physical channels via wireless communication / connections 150a, 150b, and 150c. For this purpose, at least a portion of the configuration information for configuring the process of transmitting / receiving wireless signals, various signal processing processes (e.g., channel coding / decoding, modulation / demodulation, and resource mapping / demapping), and resource allocation processes can be performed based on various proposals of this disclosure.

[0314] Examples of wireless devices that utilize this disclosure

[0315] Figure 13 A wireless device applicable to this disclosure is shown.

[0316] Reference Figure 13 The first wireless device 100 and the second wireless device 200 can transmit wireless signals via various RATs (e.g., LTE and NR). {The first wireless device 100 and the second wireless device 200} can correspond to... Figure 12 {Wireless Device 100x and BS 200} and / or {Wireless Device 100x and Wireless Device 100x}.

[0317] The first wireless device 100 may include one or more processors 102 and one or more memories 104, and also includes one or more transceivers 106 and / or one or more antennas 108. The processors 102 may control the memories 104 and / or the transceivers 106, and may be configured to implement the descriptions, functions, processes, proposals, methods, and / or operation flowcharts disclosed herein. For example, the processors 102 may process information in the memories 104 to generate a first information / signal, and then transmit a wireless signal including the first information / signal via the transceivers 106. The processors 102 may receive a wireless signal including a second information / signal via the transceivers 106, and then store the information obtained by processing the second information / signal in the memories 104. The memories 104 may be connected to the processors 102 and may store various information relating to the operation of the processors 102. For example, the memories 104 may store software code including instructions for performing all or part of the processing controlled by the processors 102 or for performing the descriptions, functions, processes, proposals, methods, and / or operation flowcharts disclosed herein. Processor 102 and memory 104 may be part of a communication modem / circuit / chip designed to implement RAT (e.g., LTE or NR). Transceiver 106 may be connected to processor 102 and transmit and / or receive wireless signals via one or more antennas 108. Each transceiver 106 may include a transmitter and / or a receiver. Transceiver 106 may be used interchangeably with a radio frequency (RF) unit. In this disclosure, the wireless device may be a communication modem / circuit / chip.

[0318] The second wireless device 200 may include one or more processors 202 and one or more memories 204, and also includes one or more transceivers 206 and / or one or more antennas 208. The processors 202 may control the memories 204 and / or the transceivers 206, and may be configured to implement the descriptions, functions, processes, proposals, methods, and / or operation flowcharts disclosed herein. For example, the processors 202 may process information in the memories 204 to generate third information / signals, and then transmit a wireless signal including the third information / signals via the transceivers 206. The processors 202 may receive wireless signals including fourth information / signals via the transceivers 206, and then store the information obtained by processing the fourth information / signals in the memories 204. The memories 204 may be connected to the processors 202 and store various information relating to the operation of the processors 202. For example, the memories 204 may store software code including instructions for performing all or part of the processing controlled by the processors 202 or for performing the descriptions, functions, processes, proposals, methods, and / or operation flowcharts disclosed herein. Processor 202 and memory 204 may be part of a communication modem / circuit / chip designed to implement RAT (e.g., LTE or NR). Transceiver 206 may be connected to processor 202 and transmit and / or receive wireless signals via one or more antennas 208. Each transceiver 206 may include a transmitter and / or a receiver. Transceiver 206 may be used interchangeably with an RF unit. In this disclosure, the wireless device may be a communication modem / circuit / chip.

[0319] The hardware elements of wireless devices 100 and 200 will now be described in more detail. One or more protocol layers may be implemented by (but not limited to) one or more processors 102 and 202. For example, one or more processors 102 and 202 may implement one or more layers (e.g., functional layers such as Physical (PHY), Media Access Control (MAC), Radio Link Control (RLC), Packet Data Convergence Protocol (PDCP), RRC, and Service Data Adaptation Protocol (SDAP). One or more processors 102 and 202 may generate one or more Protocol Data Units (PDUs) and / or one or more Service Data Units (SDUs) in accordance with the descriptions, functions, procedures, proposals, methods, and / or operation flowcharts disclosed in this document. One or more processors 102 and 202 may generate messages, control information, data, or information in accordance with the descriptions, functions, procedures, proposals, methods, and / or operation flowcharts disclosed in this document, and provide such messages, control information, data, or information to one or more transceivers 106 and 206. One or more processors 102 and 202 may generate signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data, or information, in accordance with the descriptions, functions, processes, proposals, methods, and / or operation flowcharts disclosed in this document, and provide the generated signals to one or more transceivers 106 and 206. One or more processors 102 and 202 may receive signals (e.g., baseband signals) and acquire PDUs, SDUs, messages, control information, data, or information from one or more transceivers 106 and 206, in accordance with the descriptions, functions, processes, proposals, methods, and / or operation flowcharts disclosed in this document.

[0320] One or more processors 102 and 202 may be referred to as controllers, microcontrollers, microprocessors, or microcomputers. One or more processors 102 and 202 may be implemented by hardware, firmware, software, or a combination thereof. For example, one or more application-specific integrated circuits (ASICs), one or more digital signal processors (DSPs), one or more digital signal processing devices (DSPDs), one or more programmable logic devices (PLDs), or one or more field-programmable gate arrays (FPGAs) may be included in one or more processors 102 and 202. The descriptions, functions, processes, proposals, methods, and / or operation flowcharts disclosed in this document may be implemented using firmware or software, and the firmware or software may be configured to include modules, processes, or functions. Firmware or software configured to execute the descriptions, functions, processes, proposals, methods, and / or operation flowcharts disclosed in this document may be included in one or more processors 102 and 202 or may be stored in one or more memories 104 and 204 and driven by one or more processors 102 and 202. The descriptions, functions, processes, proposals, methods, and / or operation flowcharts disclosed in this document may be implemented using firmware or software in the form of code, instructions, and / or instruction sets.

[0321] One or more memories 104 and 204 may be connected to one or more processors 102 and 202 and store various types of data, signals, messages, information, programs, code, instructions, and / or commands. One or more memories 104 and 204 may be configured to include read-only memory (ROM), random access memory (RAM), electrically erasable programmable read-only memory (EPROM), flash memory, hard disk drive, registers, cache memory, computer-readable storage media, and / or combinations thereof. One or more memories 104 and 204 may be located internally and / or externally to one or more processors 102 and 202. One or more memories 104 and 204 may be connected to one or more processors 102 and 202 via various technologies such as wired or wireless connections.

[0322] One or more transceivers 106 and 206 may transmit user data, control information, and / or wireless signals / channels mentioned in the methods and / or operation flowcharts of this document to one or more other devices. One or more transceivers 106 and 206 may receive user data, control information, and / or wireless signals / channels mentioned in the descriptions, functions, processes, proposals, methods, and / or operation flowcharts disclosed in this document from one or more other devices. For example, one or more transceivers 106 and 206 may be connected to one or more processors 102 and 202 and transmit and receive wireless signals. For example, one or more processors 102 and 202 may perform control to enable one or more transceivers 106 and 206 to transmit user data, control information, or wireless signals to one or more other devices. One or more processors 102 and 202 may perform control to enable one or more transceivers 106 and 206 to receive user data, control information, or wireless signals from one or more other devices. One or more transceivers 106 and 206 may be connected to one or more antennas 108 and 208, and one or more transceivers 106 and 206 may be configured to transmit and receive user data, control information, and / or radio signals / channels mentioned in the descriptions, functions, processes, proposals, methods, and / or operation flowcharts disclosed in this document through one or more antennas 108 and 208. In this document, one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). One or more transceivers 106 and 206 may convert received radio signals / channels from RF band signals to baseband signals for processing by one or more processors 102 and 202. One or more transceivers 106 and 206 may convert user data, control information, and radio signals / channels processed by one or more processors 102 and 202 from baseband signals to RF band signals. For this purpose, one or more transceivers 106 and 206 may include (analog) oscillators and / or filters.

[0323] Examples of the use of wireless devices applying this disclosure

[0324] Figure 14 Another example of a wireless device applied to this disclosure is shown. The wireless device can be adapted according to use cases / services (see reference). Figure 12 It can be realized in various forms.

[0325] Reference Figure 14 Wireless devices 100 and 200 can correspond to Figure 13The wireless devices 100 and 200 can be configured to include various elements, components, units / parts, and / or modules. For example, each of the wireless devices 100 and 200 may include a communication unit 110, a control unit 120, a memory unit 130, and an additional component 140. The communication unit 110 may include a communication circuit 112 and a transceiver 114. For example, the communication circuit 112 may include... Figure 13 One or more processors 102 and 202 and / or one or more memories 104 and 204. For example, transceiver 114 may include Figure 13 One or more transceivers 106 and 206 and / or one or more antennas 108 and 208. Control unit 120 is electrically connected to communication unit 110, memory 130, and add-on components 140, and provides overall control of the wireless device. For example, control unit 120 can control the electrical / mechanical operation of the wireless device based on programs / code / instructions / information stored in memory unit 130. Control unit 120 can transmit information stored in memory unit 130 to an external source (e.g., other communication devices) via communication unit 110 through a wireless / wired interface, or store information received from an external source (e.g., other communication devices) via communication unit 110 in memory unit 130 via a wireless / wired interface.

[0326] The add-on component 140 can be configured in various ways depending on the type of wireless device. For example, the add-on component 140 may include at least one of a power supply unit / battery, an input / output (I / O) unit, a drive unit, and a computing unit. The wireless device can be configured as (but is not limited to) a robot. Figure 12 100a), vehicles ( Figure 12 100b-1 and 100b-2), XR device ( Figure 12 100c), handheld device ( Figure 12 100d), home appliances ( Figure 12 100e), IoT devices ( Figure 12 100f), digital broadcasting terminals, holographic devices, public safety devices, MTC devices, medical devices, fintech devices (or financial devices), security devices, climate / environmental devices, AI servers / devices ( Figure 12 400), BS ( Figure 12 This can be achieved through methods such as 200 (network nodes, etc.). Depending on the usage / service, the wireless device can be mobile or fixed.

[0327] exist Figure 14In wireless devices 100 and 200, all elements, components, units / parts, and / or modules can be connected to each other via wired interfaces, or at least a portion thereof can be wirelessly connected via communication unit 110. For example, in each of wireless devices 100 and 200, control unit 120 and communication unit 110 can be wired connected, and control unit 120 and first units (e.g., 130 and 140) can be wirelessly connected via communication unit 110. The various elements, components, units / parts, and / or modules in wireless devices 100 and 200 may also include one or more elements. For example, control unit 120 may be configured using a collection of one or more processors. For example, control unit 120 may be configured using a collection of communication control processors, application processors, electronic control units (ECUs), graphics processing units, and memory control processors. In another example, memory 130 may be configured using RAM, dynamic RAM (DRAM), ROM, flash memory, volatile memory, non-volatile memory, and / or combinations thereof.

[0328] Examples of vehicles or autonomous vehicles that utilize this disclosure

[0329] Figure 15 The present disclosure illustrates a vehicle or autonomous vehicle. The vehicle or autonomous vehicle can be implemented as a mobile robot, car, train, manned / unmanned aerial vehicle (AV), boat, etc.

[0330] Reference Figure 15 The vehicle or autonomous vehicle 100 may include an antenna unit 108, a communication unit 110, a control unit 120, a drive unit 140a, a power supply unit 140b, a sensor unit 140c, and an autonomous driving unit 140d. The antenna unit 108 may be configured as part of the communication unit 110. Blocks 110 / 130 / 140a to 140d respectively correspond to... Figure 14 Blocks 110 / 130 / 140.

[0331] Communication unit 110 can send and receive signals (e.g., data and control signals) to and from external devices such as other vehicles, BSs (e.g., gNBs and roadside units), and servers. Control unit 120 can perform various operations by controlling the components of the vehicle or autonomous vehicle 100. Control unit 120 may include an ECU. Drive unit 140a enables the vehicle or autonomous vehicle 100 to travel on a road. Drive unit 140a may include an engine, motor, powertrain, wheels, brakes, steering mechanism, etc. Power supply unit 140b can supply power to the vehicle or autonomous vehicle 100 and includes wired / wireless charging circuitry, battery, etc. Sensor unit 140c can acquire information about vehicle status, surrounding environment, user information, etc. Sensor unit 140c may include inertial measurement unit (IMU) sensors, collision sensors, wheel sensors, speed sensors, slope sensors, weight sensors, heading sensors, position modules, vehicle forward / reverse sensors, battery sensors, fuel sensors, tire sensors, steering sensors, temperature sensors, humidity sensors, ultrasonic sensors, lighting sensors, pedal position sensors, etc. Autonomous driving unit 140d can implement technologies for maintaining the vehicle within its lane, technologies for automatically adjusting speed (e.g., adaptive cruise control), technologies for autonomously driving along a determined path, and technologies for automatically setting a route if a destination is set, etc.

[0332] For example, communication unit 110 can receive map data, traffic information data, etc., from an external server. Autonomous driving unit 140d can generate autonomous driving routes and driving plans from the acquired data. Control unit 120 can control drive unit 140a, enabling the vehicle or autonomous vehicle 100 to move along the autonomous driving route according to the driving plan (e.g., speed / direction control). During autonomous driving, communication unit 110 can acquire recent traffic information data from an external server non-periodically / periodically, and acquire surrounding traffic information data from nearby vehicles. During autonomous driving, sensor unit 140c can acquire information about vehicle status and / or surrounding environment. Autonomous driving unit 140d can update the autonomous driving route and driving plan based on newly acquired data / information. Communication unit 110 can transmit information about vehicle location, autonomous driving route, and / or driving plan to an external server. The external server can use AI technology to predict traffic information data based on information collected from the vehicle or autonomous vehicle, and provide the predicted traffic information data to the vehicle or autonomous vehicle.

[0333] Those skilled in the art will understand that this disclosure may be implemented in other specific ways besides those set forth herein without departing from the spirit and essential characteristics of this disclosure. Therefore, the above embodiments are to be construed as illustrative in all respects and not restrictive. The scope of this disclosure should be determined by the appended claims and their legal equivalents (rather than the foregoing description), and all changes falling within the meaning and scope of the appended claims are intended to be covered therewith.

[0334] Industrial applicability

[0335] As stated above, this disclosure applies to various wireless communication systems.

Claims

1.A method performed by a user equipment (UE) supporting a non-terrestrial network (NTN) in a wireless communication system, the method comprising: receiving, by a serving satellite, a system information block (SIB) including NTN-specific parameters for a target satellite, wherein the NTN-specific parameters include (i) a parameter for a common timing advance (TA) value, and (ii) a parameter for a drift rate of the common TA value; and determining a current common TA value related to a target satellite based on the common TA value, the drift rate, a time interval between a reference time of the common TA value and a current reference time, and a UE-specific TA value related to the target satellite based on a position of the target satellite through ephemeris of the target satellite and a position of the UE; and performing a change of the serving satellite based on a total TA value determined by adding the current common TA value and the UE-specific TA value. 2.The method of claim 1, wherein a parameter for a reference time of the common TA value is included in the SIB. 3.A user equipment (UE) supporting a non-terrestrial network (NTN) in a wireless communication system, the user equipment comprising: at least one transceiver; at least one processor; and at least one memory operatively connected to the at least one processor and storing instructions which, when executed, enable the at least one processor to perform specific operations including: receiving, by a serving satellite, a system information block (SIB) including NTN-specific parameters for a target satellite, wherein the NTN-specific parameters include (i) a parameter for a common timing advance (TA) value, and (ii) a parameter for a drift rate of the common TA value; and determining a current common TA value related to a target satellite based on the common TA value, the drift rate, a time interval between a reference time of the common TA value and a current reference time, and a UE-specific TA value related to the target satellite based on a position of the target satellite through ephemeris of the target satellite and a position of the UE; and performing a change of the serving satellite based on a total TA value determined by adding the current common TA value and the UE-specific TA value. 4.The user equipment of claim 3, wherein a parameter for a reference time of the common TA value is included in the SIB.

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