Method and apparatus for transmitting or receiving uplink information in satellite communication system

Abstract

The present disclosure relates to a 5G communication technology for supporting a higher data transmission rate beyond a 4G system and a system therefor. A method performed by a terminal according to an embodiment of the present disclosure may comprise the steps of: receiving configuration information related to physical uplink shared channel (PUSCH) repeated transmission through higher layer signaling; and transmitting a plurality of PUSCHs corresponding to the PUSCH repeated transmission in a plurality of time slots based on the pre-compensation.

Description

Technical Field

[0001] The present disclosure relates to a communication system, and more particularly, to a method for transmitting and receiving uplink information in a satellite communication system. Background Art

[0002] The fifth generation (5G) mobile communication technology defines a wide frequency band so that high transmission rates and new services are possible, and can be implemented not only in "below 6 GHz" frequency bands such as 3.50 GHz, but also in "above 6 GHz" frequency bands called mmWave (millimeter wave) including 28 GHz and 39 GHz. In addition, it has been considered to implement 6G mobile communication technology (called Beyond 5G System) in the terahertz (THz) frequency band (e.g., 95 GHz to 3 THz frequency band) in order to achieve a transmission rate fifty times faster than that of 5G mobile communication technology and an ultra-low latency one-tenth of that of 5G mobile communication technology.

[0003] At the beginning of the development of 5G mobile communication technology, in order to support services and meet performance requirements related to enhanced mobile broadband (eMBB), ultra-reliable low latency communication (URLLC), and massive machine type communication (mMTC), there has been ongoing standardization on the following: beamforming and massive MIMO for mitigating radio wave path loss and increasing radio wave transmission distance in mmWave, support parameter sets for efficient utilization of mmWave resources and dynamic operation of time slot formats (e.g., operating multiple subcarrier spacings), initial access technology for supporting multi-beam transmission and broadband, new channel coding methods for definition and operation of bandwidth parts (BWPs), such as low-density parity-check (LDPC) codes for large-volume data transmission and polar codes for high-reliability transmission of control information, L2 preprocessing, and network slicing for providing dedicated networks dedicated to specific services.

[0004] Currently, in view of the services to be supported by the 5G mobile communication technology, discussions on improvements and performance enhancements of initial 5G mobile communication technology are ongoing, and there is already physical layer standardization on technologies such as Vehicle-to-Everything (V2X) for assisting driving determination by autonomous vehicles based on information about the location and status of the vehicle sent by the vehicle and for enhancing user convenience, New Radio Unlicensed (NR-U) for system operation that complies with various regulatory-related requirements in unlicensed bands, NR UE power save, Non-Terrestrial Network (NTN) which is UE satellite direct communication for providing coverage in areas where communication with terrestrial networks is unavailable, and positioning.

[0005] In addition, standardization has been conducted in the air interface architecture / protocol on technologies such as: Industrial Internet of Things (IIoT) for supporting new services through interworking and integration with other industries, Integrated Access and Backhaul (IAB) for providing nodes for network service area expansion by supporting wireless backhaul links and access links in an integrated manner, mobility enhancements including conditional handover and dual active protocol stack (DAPS) handover, and two-step random access (two-step RACH for NR) for simplifying the random access procedure. There is also ongoing standardization in the system architecture / services on 5G baseline architecture (e.g., service-based architecture or service-based interface) for combining network function virtualization (NFV) and software defined network (SDN) technologies, and mobile edge computing (MEC) for receiving services based on UE location.

[0006] As 5G mobile communication systems are commercialized, the already exponentially growing number of connected devices will be connected to the communication network, and it is accordingly expected that enhanced functionality and performance of the 5G mobile communication system and integrated operations of connected devices will be necessary. To this end, new research is planned in conjunction with extended reality (XR) to efficiently support augmented reality (AR), virtual reality (VR), mixed reality (MR), etc., to improve 5G performance and reduce complexity by utilizing artificial intelligence (AI) and machine learning (ML), AI service support, metaverse service support, and drone communications.

[0007] Furthermore, such development of 5G mobile communication systems will serve as a foundation for developing not only new waveforms for providing coverage in the terahertz band of 6G mobile communication technology, multi-antenna transmission technologies such as full-dimensional MIMO (FD-MIMO), array antennas, and massive antennas, metamaterial-based lenses and antennas for improving signal coverage in the terahertz band, and high-dimensional spatial multiplexing technologies using orbital angular momentum (OAM) and reconfigurable smart surfaces (RIS), but also full-duplex technologies for improving frequency efficiency and improving system networks in 6G mobile communication technology, AI-based communication technologies for implementing system optimization by utilizing satellites and artificial intelligence (AI) from the design stage and internalizing end-to-end AI support functions, and next-generation distributed computing technologies for implementing services at a complexity level that exceeds the limits of UE operating capabilities by utilizing ultra-high-performance communication and computing resources.

[0008] As discussed above, as mobile communication systems develop, various services can be provided, solutions for efficiently providing such services are required, and in particular, solutions for optimizing non-public networks are required.

[0009] At the same time, as the cost of satellite launches has dropped significantly in the late 2010s and 2020s, the number of operators seeking to provide communication services via satellite is increasing. As a result, satellite networks are becoming the next-generation network system to complement existing terrestrial networks. Satellite networks cannot yet provide the same level of user experience as terrestrial networks, but the advantage of satellite networks is that they can provide communication services in areas where terrestrial network construction is difficult or in disaster situations. As mentioned above, they have also become more economical due to the recent rapid decline in satellite launch costs. In addition, multiple companies and the 3GPP standards organization are also promoting direct communication between smartphones and satellites. Summary of the invention

[0010] Technical issues

[0011] The disclosed embodiments are to provide an apparatus and method capable of effectively providing services in a wireless communication system such as a satellite communication system.

[0012] Solution to the problem

[0013] According to an embodiment of the present disclosure, a method for a terminal to perform satellite communication may include: receiving time offset information from a base station; calculating a timing advance (TA) value based on the received time offset information; applying the calculated TA value; sending information about the applied TA value to the base station; and receiving information for correcting the TA value from the base station.

[0014] According to an embodiment of the present disclosure, a method performed by a terminal in a communication system may be provided.

[0015] According to an embodiment of the present disclosure, the method may include receiving configuration information related to physical uplink shared channel (PUSCH) repetitive transmission through higher layer signaling.

[0016] According to an embodiment of the present disclosure, the method may include transmitting a plurality of PUSCHs corresponding to PUSCH repetition transmission in a plurality of time slots based on pre-compensation.

[0017] According to an embodiment of the present disclosure, pre-compensation can be performed to satisfy that the phase difference between the phase associated with the PUSCH mapped to the first time slot among multiple time slots and the phase associated with the PUSCH mapped to the second time slot among the multiple time slots is within a predefined range for demodulation reference signal (DM-RS) bundling.

[0018] According to an embodiment of the present disclosure, DM-RS bundling may be used for PUSCH repeated transmission.

[0019] According to an embodiment of the present disclosure, the first time slot and the second time slot may be any two consecutive time slots included in the plurality of time slots.

[0020] According to an embodiment of the present disclosure, the first time slot may be a time slot to which a PUSCH associated with a minimum phase among multiple PUSCHs is mapped, and the second time slot is a time slot to which a PUSCH associated with a maximum phase among multiple PUSCHs is mapped.

[0021] According to an embodiment of the present disclosure, pre-compensation may be used for PUSCH repetition transmission in a non-terrestrial network (NTN).

[0022] According to an embodiment of the present disclosure, the method may further include transmitting a plurality of DM-RSs to which DM-RS bundling is applied.

[0023] According to an embodiment of the present disclosure, configuration information for DM-RS bundling may be received through higher layer signaling.

[0024] According to an embodiment of the present disclosure, the method may further include sending, by the terminal, capability information related to supporting pre-compensation.

[0025] According to an embodiment of the present disclosure, a terminal in a communication system may be provided.

[0026] According to an embodiment of the present disclosure, a terminal may include: a transceiver; and a processor connected to the transceiver.

[0027] According to an embodiment of the present disclosure, the processor may be configured to receive configuration information related to physical uplink shared channel (PUSCH) repetitive transmission through higher layer signaling.

[0028] According to an embodiment of the present disclosure, the processor may be configured to transmit a plurality of PUSCHs corresponding to PUSCH repetition transmission in a plurality of time slots based on pre-compensation.

[0029] According to an embodiment of the present disclosure, pre-compensation can be performed to satisfy that the phase difference between the phase associated with the PUSCH mapped to the first time slot among multiple time slots and the phase associated with the PUSCH mapped to the second time slot among the multiple time slots is within a predefined range for demodulation reference signal (DM-RS) bundling.

[0030] According to an embodiment of the present disclosure, DM-RS bundling may be used for PUSCH repeated transmission.

[0031] According to an embodiment of the present disclosure, the first time slot and the second time slot may be any two consecutive time slots included in the plurality of time slots.

[0032] According to an embodiment of the present disclosure, the first time slot may be a time slot to which a PUSCH associated with a minimum phase among multiple PUSCHs is mapped, and the second time slot is a time slot to which a PUSCH associated with a maximum phase among multiple PUSCHs is mapped.

[0033] According to an embodiment of the present disclosure, pre-compensation may be used for PUSCH repetition transmission in a non-terrestrial network (NTN).

[0034] According to an embodiment of the present disclosure, the processor may be configured to transmit a plurality of DM-RSs to which DM-RS bundling is applied.

[0035] According to an embodiment of the present disclosure, configuration information for DM-RS bundling may be received via higher layer signaling.

[0036] According to an embodiment of the present disclosure, the processor may be configured to allow the terminal to transmit capability information related to supporting pre-compensation.

[0037] According to an embodiment of the present disclosure, a method performed by a base station in a communication system may be provided.

[0038] According to an embodiment of the present disclosure, the method may include sending configuration information related to repeated transmission of a physical uplink shared channel (PUSCH) to a terminal through upper layer signaling.

[0039] According to an embodiment of the present disclosure, the method may include receiving a plurality of PUSCHs corresponding to PUSCH repetition transmission from a terminal in a plurality of time slots.

[0040] According to an embodiment of the present disclosure, a phase difference between a phase associated with a PUSCH mapped to a first time slot among a plurality of time slots and a phase associated with a PUSCH mapped to a second time slot among the plurality of time slots may be included in a predefined range for demodulation reference signal (DM-RS) bundling,

[0041] According to an embodiment of the present disclosure, DM-RS bundling may be used for PUSCH repeated transmission.

[0042] According to an embodiment of the present disclosure, the first time slot and the second time slot may be any two consecutive time slots included in the plurality of time slots.

[0043] According to an embodiment of the present disclosure, the first time slot may be a time slot to which a PUSCH associated with a minimum phase among multiple PUSCHs is mapped, and the second time slot is a time slot to which a PUSCH associated with a maximum phase among multiple PUSCHs is mapped.

[0044] According to an embodiment of the present disclosure, the method may further include receiving, by the terminal, capability information related to supporting pre-compensation.

[0045] According to an embodiment of the present disclosure, pre-compensation may be associated with the phase difference being included in a predefined range.

[0046] According to an embodiment of the present disclosure, a base station in a communication system may be provided.

[0047] According to an embodiment of the present disclosure, a base station may include: a transceiver; and a processor connected to the transceiver.

[0048] According to an embodiment of the present disclosure, the processor may be configured to send configuration information related to repeated transmission of a physical uplink shared channel (PUSCH) to a terminal through higher layer signaling.

[0049] According to an embodiment of the present disclosure, the processor may be configured to receive a plurality of PUSCHs corresponding to PUSCH repetition transmission from a terminal in a plurality of time slots.

[0050] According to an embodiment of the present disclosure, a phase difference between a phase associated with a PUSCH mapped to a first time slot among a plurality of time slots and a phase associated with a PUSCH mapped to a second time slot among the plurality of time slots may be included in a predefined range for demodulation reference signal (DM-RS) bundling,

[0051] According to an embodiment of the present disclosure, DM-RS bundling may be used for PUSCH repeated transmission.

[0052] According to an embodiment of the present disclosure, the processor may be configured to allow the terminal to receive capability information related to supporting pre-compensation.

[0053] According to an embodiment of the present disclosure, pre-compensation may be associated with the phase difference being included in a predefined range.

[0054] Advantageous Effects of the Invention

[0055] The present disclosure provides an apparatus and method capable of efficiently providing a service in a wireless communication system such as a satellite communication system. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 2 is a schematic diagram showing a basic structure of a time-frequency domain according to an embodiment of the present disclosure, where the time-frequency domain is a radio resource region for sending data or a control channel in a downlink or uplink of an NR system.

[0057] Figure 2 is a schematic diagram showing the synchronization signal (SS) and physical broadcast channel (PBCH) of the NR system mapped in the frequency domain and the time domain.

[0058] Figure 3 is a schematic diagram showing symbols in which an SS / PBCH block can be transmitted based on subcarrier spacing.

[0059] Figure 4is a schematic diagram showing an example of a control resource set (CORESET) in which a downlink control channel is transmitted in a 5G wireless communication system according to an embodiment of the present disclosure.

[0060] Figure 5 is a diagram schematically illustrating an example of a message delivered from a MAC layer to a physical layer in a downlink in a communication system according to an embodiment of the present disclosure.

[0061] Figure 6 is a diagram schematically illustrating an example of a message delivered from a MAC layer to a physical layer in an uplink in a communication system according to an embodiment of the present disclosure.

[0062] Figure 7 is a diagram illustrating an example of a process of dividing one transport block (TB) into a plurality of code blocks (CBs) and adding a CRC according to an embodiment of the present disclosure.

[0063] Figure 8 is a schematic diagram showing a processing time of a UE according to a timing advance when the UE receives a first signal and sends a second signal in response to the first signal in a 5G or NR system according to an embodiment of the present disclosure.

[0064] Fig. 9 is a schematic diagram showing an example of scheduling and sending data (eg, TB) according to time slots, receiving HARQ-ACK feedback of the corresponding data, and performing retransmission according to the feedback.

[0065] Fig.10 is a schematic diagram illustrating an example of a communication system using a satellite according to an embodiment of the present disclosure.

[0066] Fig.11 is a schematic diagram showing the revolution period of a communication satellite around the earth according to the altitude or orbital altitude of the satellite according to an embodiment of the present disclosure.

[0067] Fig.12 is a schematic diagram illustrating the concept of direct communication between a satellite and a UE according to an embodiment of the present disclosure.

[0068] Fig.13 is a schematic diagram illustrating a scenario using direct communication between a satellite and a UE.

[0069] Fig.14 is a diagram illustrating an example of calculation of an expected data throughput in an uplink when a LEO satellite having an altitude of 1200 km and a UE perform direct communication according to an embodiment of the present disclosure.

[0070] Fig.15is a diagram illustrating an example of calculation of an expected data throughput in an uplink when a GEO satellite having an altitude of 35,786 km and a ground UE perform direct communication according to an embodiment of the present disclosure.

[0071] Fig.16 It is a schematic diagram showing the path loss value according to the path loss model between the UE and the satellite and the path loss according to the path loss model between the UE and the ground network communication base station.

[0072] Fig.17 is a schematic diagram showing an equation for calculating the amount of Doppler shift experienced by a signal when a signal sent from a satellite is received by a user on the ground and its result according to an embodiment of the present disclosure, based on the altitude and position of the satellite and the position of the user of the UE on the ground.

[0073] Fig.18 is a schematic diagram showing the velocity of a satellite calculated at the altitude of the satellite.

[0074] Fig.19 is a schematic diagram showing Doppler frequency shift experienced by different UEs in a beam transmitted by a satellite to the ground according to an embodiment of the present disclosure.

[0075] Fig. 20 is a schematic diagram illustrating a difference between Doppler frequency shifts generated within one beam according to a position of a satellite determined by an elevation angle according to an embodiment of the present disclosure.

[0076] Fig.21 is a schematic diagram illustrating a delay time from a UE to a satellite according to a position of a satellite determined by an elevation angle and a round-trip delay time between the UE, the satellite, and a base station according to an embodiment of the present disclosure.

[0077] Fig. 22 is a schematic diagram illustrating a maximum difference in round-trip delay time depending on a position of a user within a beam according to an embodiment of the present disclosure.

[0078] Fig.23 is a diagram illustrating an example of an information structure of a RAR according to an embodiment of the present disclosure.

[0079] Fig.24 is a schematic diagram showing an example relationship between a PRACH preamble configuration resource and an RAR reception time point in an LTE system according to an embodiment of the present disclosure.

[0080] Fig.25 is a schematic diagram showing an example relationship between a PRACH preamble configuration resource and an RAR reception time point in a 5G NR system according to an embodiment of the present disclosure.

[0081] Fig.26 is a schematic diagram showing an example of downlink frame timing and uplink frame timing in a UE according to an embodiment of the present disclosure.

[0082] Fig. 27 is a schematic diagram illustrating an example of continuous movement of a satellite relative to a UE located on the ground or the earth when the satellite revolves around the earth along a satellite orbit according to an embodiment of the present disclosure.

[0083] Fig.28 is a schematic diagram showing an example structure of an artificial satellite according to an embodiment of the present disclosure.

[0084] Fig.29 FIG. 1 is a diagram showing a UE according to an embodiment of the present disclosure determining N from initial access TA Schematic diagram of an example process.

[0085] Fig.30 FIG. 1 is a diagram showing a UE according to an embodiment of the present disclosure determining N from initial access TA 、N TA,UE-specific and N TA,common Schematic diagram of an example process.

[0086] Fig.31 is a schematic diagram schematically illustrating another example of an operation process of a UE in a communication system according to an embodiment of the present disclosure.

[0087] Fig.32 is a schematic diagram schematically illustrating another example of an operation process of a UE in a communication system according to an embodiment of the present disclosure.

[0088] Fig.33 is a schematic diagram illustrating an example operation of a base station for TA value reporting of a UE according to an embodiment of the present disclosure.

[0089] Fig.34 is a diagram illustrating an example operation of a UE for TA value reporting of the UE according to an embodiment of the present disclosure.

[0090] Fig.35 is a schematic diagram illustrating an example of a difference in propagation delay between a terrestrial network and a satellite network according to an embodiment of the present disclosure.

[0091] Fig.36 is a flow chart for performing satellite network connection of a UE according to an embodiment.

[0092] Fig.37 FIG. 2 is a diagram showing a method for configuring a configured TDW and an actual TDW for simultaneous channel estimation.

[0093] Fig.38is a flow chart illustrating the operation of a UE for simultaneous channel estimation of a base station according to an embodiment.

[0094] Fig.39 is a flowchart illustrating the operation of a UE according to an embodiment.

[0095] Fig.40 is a flowchart illustrating the operation of a base station according to an embodiment.

[0096] Fig.41 is a block diagram showing an internal structure of a UE according to an embodiment of the present disclosure.

[0097] Fig.42 is a block diagram showing an internal structure of a satellite according to an embodiment of the present disclosure.

[0098] Fig.43 is a block diagram showing an internal structure of a base station according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0099] The new radio (NR) access technology as the new 5G communication has been designed to allow various services to be freely multiplexed in time and frequency resources, and thus waveforms / parameter sets, reference signals, etc. can be dynamically or freely allocated according to the needs of the service. In order to provide the best service to UE in wireless communication, data transmission optimized by measuring the quality and interference amount of the channel is important, and therefore accurate channel state measurement must be performed. However, unlike 4G communication, where the channel and interference characteristics do not change significantly depending on the frequency resources, the channel and interference characteristics of the 5G channel may change significantly depending on the service, and therefore it is necessary to support a subset of frequency resource groups (FRGs) to divide and measure the channel and interference characteristics. At the same time, in the NR system, the types of services supported can be divided into enhanced mobile broadband (eMBB), massive machine type communication (mMTC), ultra-reliable and low-latency communication (URLLC), etc. It can be understood that eMBB is a service for high-speed transmission of large amounts of data, mMTC is a service for minimizing terminal power and connecting multiple terminals, and URLLC is a service for high reliability and low latency. Depending on the type of service applied to the terminal, different requirements may be applied.

[0100] In this way, multiple services can be provided to users in a communication system, and in order to provide such multiple services to users, a method capable of providing each service within the same time interval according to the characteristics of each service and an apparatus using the method are required.

[0101] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0102] When describing the embodiments, descriptions related to technical contents known in the art and not directly related to the present disclosure will be omitted. Such unnecessary omissions are intended to prevent the main idea of ​​the present disclosure from being obscured and to convey the main idea more clearly.

[0103] For the same reason, in the accompanying drawings, some elements may be exaggerated, omitted or schematically shown. In addition, the size of each element does not fully reflect the actual size. In the accompanying drawings, the same or corresponding elements are provided with the same reference numerals.

[0104] By referring to the embodiments described in detail below in conjunction with the accompanying drawings, the advantages and features of the present disclosure and the ways to achieve them will be apparent. However, the present disclosure is not limited to the embodiments set forth below and can be implemented in various different forms. The following embodiments are provided only to fully disclose the present disclosure and inform those skilled in the art of the scope of the present disclosure, and the present disclosure is defined only by the scope of the appended claims. Throughout the specification, the same or similar reference numerals designate the same or similar elements.

[0105] In this article, it will be understood that each frame of the flowchart diagram and the combination of frames in the flowchart diagram can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device create a device for implementing the function specified in the (multiple) flowchart frame. These computer program instructions can also be stored in a computer-available or computer-readable memory, which can instruct the computer or other programmable data processing device to operate in a particular way, so that the instructions stored in the computer-available or computer-readable memory produce an article including an instruction device, which implements the function specified in the (multiple) flowchart frame. The computer program instructions can also be loaded on a computer or other programmable data processing device, so that a series of operating steps are performed on a computer or other programmable device, thereby generating a computer-implemented process, so that the instructions executed on a computer or other programmable device provide steps for implementing the function specified in the (multiple) flowchart frame.

[0106] In addition, each box of the flowchart diagram can represent a module, segment or part of the code, which includes one or more executable instructions for implementing (multiple) specified logical functions. It should also be noted that in some alternative embodiments, the functions mentioned in the box may not occur in order. For example, depending on the corresponding function, the two boxes shown in succession can actually be executed substantially simultaneously, or the boxes can sometimes be executed in reverse order.

[0107] As used herein, "~ unit" refers to a software element or hardware element that performs a predetermined function, such as an FPGA or ASIC. However, "~ unit" does not always have a meaning limited to software or hardware. "~ unit" can be constructed to be stored in an addressable storage medium or to execute one or more processors. Therefore, "~ unit" includes, for example, elements, processes, functions, attributes, procedures, subroutines, program code segments, drivers, firmware, microcodes, circuits, data, databases, data structures, tables, arrays, and parameters such as software elements, object-oriented software elements, class elements, and task elements. The elements and functions provided by "~ unit" can be combined into a smaller number of elements and "~ unit", or divided into a larger number of elements and "~ unit". In addition, elements and "~ unit" can be implemented to reproduce one or more CPUs in a device or a secure multimedia card. Moreover, in an embodiment, "~ unit" can include one or more processors.

[0108] The wireless communication system deviated from the provision of initial voice-oriented services and evolved into a broadband wireless communication system that provides high-speed and high-quality packet data services, such as communication standards such as 3GPP's High Speed ​​Packet Access (HSPA), Long Term Evolution (LTE or Evolved Universal Terrestrial Radio Access (E-UTRA)), Advanced LTE (LTE-A), 3GPP2's High Rate Packet Data (HRPD), Ultra Mobile Broadband (UMB), and IEEE's 802.16e. In addition, the communication standard of 5G or New Radio (NR) is generated as a 5G wireless communication system.

[0109] The NR system, which is a representative example of a broadband wireless communication system, adopts orthogonal frequency division multiplexing (OFDM) in the downlink (DL) and uplink (UL). In more detail, a cyclic prefix OFDM (CP-OFDM) scheme is adopted in the DL, and a discrete Fourier transform spread OFDM (DFT-S-OFDM) scheme is adopted in the uplink together with the CP-OFDM scheme. The uplink is a wireless link through which a terminal (user equipment (UE) or mobile station (MS)) sends data or a control signal to a base station (BS) (or gNodeB), and the DL is a wireless link through which a base station sends data or a control signal to a UE. In such a multiple access scheme, generally, the data or control information of each user can be distinguished by allocating and operating the time-frequency resources on which the data or control information of each user is sent so as not to overlap with each other, that is, to establish orthogonality.

[0110] The NR system adopts a hybrid automatic repeat request (HARQ) scheme, which resends the corresponding data in the physical layer in the event of a decoding failure in the initial transmission. In the HARQ scheme, if the receiver fails to correctly decode the data, the receiver sends a negative acknowledgment (NACK) to the transmitter, which is information used to notify the transmitter of the decoding failure so as to allow the transmitter to resend the corresponding data in the physical layer. The receiver can improve the data reception performance by combining the data resent by the transmitter with the data that failed to be decoded. In addition, if the receiver correctly decodes the data, the receiver sends a confirmation (ACK) to the transmitter to notify the transmitter of the successful decoding so as to allow the transmitter to send new data.

[0111] According to an embodiment of the present disclosure, in the case where a UE intends to connect to a base station via a satellite, a large delay occurs before the radio wave arrives due to the long distance of hundreds or thousands of kilometers or more between the UE and the satellite and between the satellite and the base station on the ground. This large delay is much larger than the delay in the case where the UE and the base station perform direct communication in a terrestrial network. In addition, due to the continuous movement of the satellite, the delay between the UE, the satellite, and the base station changes over time.

[0112] Therefore, the present disclosure provides a method and apparatus in which a base station indicates a time offset, and based on the time offset, a UE performs correction so as to correct a time-varying delay that occurs due to a long distance to a satellite and movement of the satellite when the UE transmits and receives a signal to the base station via a satellite. In addition, the present disclosure provides a method and apparatus in which the UE can calculate and apply a portion of the time offset based on the position and time information of the satellite and the satellite itself, and report it to the base station.

[0113] That is, according to an embodiment of the present disclosure, in the case where a UE transmits a signal to a base station and receives a signal from a base station via a satellite, due to the long distance between the UE and the satellite, the time offset may need to be corrected. Therefore, the present disclosure provides a method and an apparatus in which a base station indicates time offset information to a UE, the UE calculates and applies a portion of a timing advance, the UE reports the timing advance information to the base station, and the UE uses the information indicated by the base station to correct the time offset.

[0114] As described above, by using the present disclosure, a UE can be connected to a base station via a satellite, the base station indicates a time offset to the UE, and the UE calculates and corrects the time offset so that signals can be effectively exchanged between the base station and the UE.

[0115] Figure 1 2 is a schematic diagram showing a basic structure of a time-frequency domain according to an embodiment of the present disclosure, where the time-frequency domain is a radio resource region for sending data or a control channel in a downlink or uplink of an NR system.

[0116] refer to Figure 1 , the horizontal axis represents the time domain, and the vertical axis represents the frequency domain. The smallest transmission unit in the time domain is an OFDM symbol, and N symb OFDM symbols 102 may be constructed as a single time slot 106. The length of a subframe may be defined as 1.0 ms, and the length of a radio frame 114 may be defined as 10 ms. The minimum transmission unit in the frequency domain is a subcarrier, and the entire system transmission bandwidth may consist of a total of N subcarriers. BW A frame may be defined as 10 ms. A subframe may be defined as 1 ms, and thus, a frame may include a total of 10 subframes. A time slot may be defined as 14 OFDM symbols (i.e., the number of symbols per time slot). ). A subframe may consist of one or more time slots, and the number of time slots in each subframe may differ based on the set value μ configured for the subcarrier spacing. Figure 1 In the example of FIG. 1 , the case where the subcarrier spacing setting value is μ = 0 and μ = 1 is shown. In the case of M = 0, one subframe can be composed of one time slot. In the case of μ = 1, one subframe can be composed of two time slots. That is, depending on the setting value μ of the subcarrier spacing, the number of time slots per subframe is can be different. Therefore, the number of time slots per frame It can also be different. Based on the subcarrier spacing setting value μ and It can be defined as shown in Table 1 below.

[0117] [Table 1]

[0118]

[0119] A UE before a radio resource control (RRC) connection can be configured by a base station via a master information block (MIB) with an initial bandwidth part (initial BWP) for initial access. More specifically, in the initial access phase, the UE can receive configuration information associated with a search space and a control resource set (CORESET) in which a physical downlink control channel (PDCCH) is transmitted via the MIB, so as to receive system information required for initial access (corresponding to the remaining system information (RMSI) or system information block 1 (SIB1)). Each of the control resource set and the search space configured via the MIB can be regarded as an identification (ID) of 0. The base station can notify the UE of configuration information associated with CORESET#0 via the MIB, such as frequency allocation information, time allocation information, parameter set, etc. In addition, the base station can notify the UE of configuration information related to the listening period and timing associated with CORESET#0, i.e., configuration information associated with search space#0, via the MIB. The UE can regard the frequency range configured as CORESET#0 obtained from the MIB as the initial bandwidth part for initial access. In this case, the identification (ID) of the initial bandwidth part can be regarded as 0.

[0120] The MIB may include information as shown in Table 2 below, but the MIB is certainly not limited to the following example.

[0121] [Table 2]

[0122]

[0123] The description of the MIB fields is as follows.

[0124] -cellBarred

[0125] The value barred means that the cell is barred, as defined in TS 38.304

[20] .

[0126] -dmrs-TypeA-Location

[0127] Position of the (first) DM-RS for the downlink (see TS 38.211

[16] , clause 7.4.1.1.2) and uplink (see TS 38.211

[16] , clause 6.4.1.1.3).

[0128] -intraFreqReselection

[0129] As specified in TS 38.304

[20] , cell selection / reselection to intra-frequency cells is controlled when the highest ranked cell is barred or considered barred by the UE.

[0130] -pdcch-ConfigSIB1

[0131] Determine the common ControlResourceSet (CORESET), common search space and necessary PDCCH parameters. If the field ssb-SubcarrierOffset indicates that SIB1 does not exist, the field pdcch-ConfigSIB1 indicates the frequency location where the UE can find the SS / PBCH block with SIB1 or the frequency range where the network does not provide the SS / PBCH block with SIB1 (see TS38.213

[13] , clause 13).

[0132] -ssb-SubcarrierOffset

[0133] Corresponding to kSSB (see TS 38.213

[13] ), kSSB is the frequency domain offset between the SSB and the entire resource block grid, expressed in the number of subcarriers. (See TS 38.211

[16] , clause 7.4.3.1).

[0134] The value range of this field may be extended by additional most significant bits encoded within the PBCH as specified in TS 38.213

[13] .

[0135] This field may indicate that the cell does not provide SIB1 and therefore CORESET#0 is not configured in the MIB (see TS 38.213

[13] , clause 13). In this case, the field pdcch-ConfigSIB1 may indicate the frequency location where the UE can (cannot) find the SS / PBCH with the control resource set and search space for SIB1 (see TS 38.213

[13] , clause 13).

[0136] -subCarrierSpacingCommon

[0137] Subcarrier spacing for SIB1, Msg.2 / 4 for initial access, paging and broadcast SI messages. If the UE acquires this MIB on FR1 carrier frequency, the value scs15or60 corresponds to 15kHz and the value scs30or120 corresponds to 30kHz. If the UE acquires this MIB on FR2 carrier frequency, the value scs15or60 corresponds to 60kHz and the value scs30or120 corresponds to 120kHz.

[0138] -systemFrameNumber

[0139] The 6 most significant bits (MSBs) of the 10-bit System Frame Number (SFN). The 4 LSBs of the SFN are transmitted in the PBCH transport block as part of the channel coding (i.e., in addition to the MIB coding), as defined in clause 7.1 of TS 38.212

[17] .

[0140] In the method for configuring the bandwidth part, a UE before RRC connection can receive configuration information associated with the initial bandwidth part via the MIB in the initial access phase. More specifically, the UE can receive the configuration of the control resource set for the downlink control channel in which the downlink control information (DCI) scheduling SIB can be sent from the MIB of the physical broadcast channel (PBCH). In this case, the bandwidth of the control resource set configured via the MIB can be regarded as the initial bandwidth part, and the UE can receive the physical downlink shared channel (PDSCH) sending the SIB via the configured initial bandwidth part. In addition to the purpose of receiving SIB, the initial bandwidth part can be used for other system information (OSI), paging or random access purposes.

[0141] In case one or more bandwidth parts are configured for the UE, the base station may indicate the change of the bandwidth part by using the bandwidth part indicator field in the DCI.

[0142] The basic resource unit in the time-frequency domain is a resource element (RE) 112, and an RE is represented by an OFDM symbol index and a subcarrier index. A resource block (RB) 108 (or a physical resource block (PRB)) may be defined as N in the frequency domain. RB 110 consecutive subcarriers. Usually, the minimum transmission unit of data is RB. In the NR system, usually, N symb =14 and N RB =12. N BW Proportional to the system transmission bandwidth. The data rate can increase in proportion to the number of RBs scheduled for the UE.

[0143] In the NR system, in the case of an FDD system that distinguishes and operates the downlink and uplink based on frequency, the downlink transmission bandwidth and the uplink transmission bandwidth may be different from each other. The channel bandwidth may represent the RF bandwidth corresponding to the system transmission bandwidth. Tables 3 and 4 respectively show a part of the correspondence between the system transmission bandwidth, subcarrier spacing, and channel bandwidth defined in the NR system in a frequency band below 6 GHz (frequency range 1 (FR1)) and a frequency band above 6 GHz (FR2). For example, in the case of an NR system with a channel bandwidth of 100 MHz and a subcarrier spacing of 30 kHz, the transmission bandwidth may include 273 RBs. N / A in the following table may be a bandwidth-subcarrier combination not supported by the NR system.

[0144] [Table 3]

[0145]

[0146] [Table 4]

[0147]

[0148] In the NR system, the frequency ranges may be defined as FR1 and FR2, respectively, as shown in Table 5 below.

[0149] [Table 5]

[0150]

[0151]

[0152] Obviously, the above ranges of FR1 and FR2 may be changed to be different and may be applied. For example, the frequency range of FR1 may be changed to be in the range of 450 MHz to 6000 MHz and may be applied.

[0153] Next, the synchronization signal (SS) / PBCH block in 5G will be described.

[0154] The SS / PBCH block may be a physical layer channel block consisting of a primary synchronization signal (SS) (PSS), a secondary SS (SSS) and a PBCH. A detailed description of the SS / PBCH block is as follows.

[0155] -PSS: It is a reference signal used for downlink time / frequency synchronization and provides a part of the cell ID information.

[0156] -SSS: It is a reference for downlink time / frequency synchronization and can provide the remaining cell ID information that PSS does not provide. In addition, SSS can be used as a reference signal for demodulating PBCH.

[0157] -PBCH: It provides the basic system information required by the UE to perform data channel and control channel transmission or reception. The basic system information may include search space related control information representing the radio resource mapping information of the control channel, scheduling control information associated with a separate data channel for transmitting system information, etc.

[0158] -SS / PBCH block: An SS / PBCH block may consist of a combination of PSS, SSS, and PBCH. A single or multiple SS / PBCH blocks may be transmitted within 5 ms, and each transmitted SS / PBCH block may be identified based on an index.

[0159] In the initial access phase, the UE can detect the PSS and SSS, and can decode the PBCH. The UE can obtain the MIB from the PBCH, thereby being configured with CORESET#0 (which can correspond to the control resource set with a control resource set index of 0). The UE can assume that the selected SS / PBCH block and the demodulation reference signal (DMRS) sent in CORESET#0 are in quasi co-location (QCL), and can monitor CORESET#0. The UE can receive system information via the downlink control information sent in CORESET#0. Based on the received system information, the UE can obtain the random access channel (RACH) related configuration information required for initial access. The UE can send a physical RACH (PRACH) to the base station considering the selected SS / PBCH index, and the base station that has received the PRACH can obtain information associated with the index of the SS / PBCH block that the UE has selected. Through these processes, the base station can know the block that the UE has selected in the SS / PBCH block and the fact that the UE monitors CORESET#0 associated with the selected block.

[0160] Figure 2 is a schematic diagram showing a synchronization signal (SS) and a physical broadcast channel (PBCH) of an NR system mapped in the frequency domain and the time domain according to an embodiment of the present disclosure.

[0161] A primary synchronization signal (PSS) 201, a secondary synchronization signal (SSS) 203, and a PBCH are mapped on 4 OFDM symbols. Each of the PSS and SSS is mapped to 12 RBs, and the PBCH is mapped to 20 RBs. Figure 2 The table in shows a frequency band of 20 RBs that varies depending on the subcarrier spacing (SCS). The resource region in which the PSS, SSS, and PBCH are transmitted is referred to as an SS / PBCH block. In addition, the SS / PBCH block may be referred to as a synchronization signal block (SSB) block.

[0162] Figure 3 is a schematic diagram illustrating symbols in which an SS / PBCH block can be transmitted based on a subcarrier spacing according to an embodiment of the present disclosure.

[0163] refer to Figure 3 , the subcarrier spacing can be configured as 15kHz, 30kHz, 120kHz, 240kHz, etc., and the position of the symbol in which the SS / PBCH block (or SSB block) can be located can be determined based on each subcarrier spacing. Figure 3 The position of the symbol where the SSB can be transmitted based on the subcarrier spacing in the symbol within 1 ms is shown, but the SSB is not always Figure 3Therefore, the location of sending the SSB block can be configured for the UE via system information or dedicated signaling.

[0164] Hereinafter, a downlink control channel in a 5G communication system will be described in more detail with reference to the accompanying drawings.

[0165] Figure 4 is a schematic diagram showing an example of a control resource set (CORESET) in which a downlink control channel is transmitted in a 5G wireless communication system according to an embodiment of the present disclosure.

[0166] Figure 4 An example is shown in which a UE bandwidth portion 210 is configured on the time axis and two control resource sets (CORESET#1 391 and CORESET#2 392) are configured within a time slot 410 on the time axis. CORESETs 391 and 402 may be configured in a specific frequency resource 393 within the total UE bandwidth portion 400 on the frequency axis. CORESETs 391 and 402 may be configured as one or more OFDM symbols on the time axis, and the CORESET may be defined as a control resource set duration 404. Figure 4 In the example of FIG. 5 , CORESET#1 391 is configured as a control resource set duration of two symbols, and CORESET#2 392 is configured as a control resource set duration of one symbol.

[0167] The control resource set in the above 5G can be configured by the base station through higher layer signaling in the UE (e.g., system information, MIB or RRC signaling). Configuring the control resource set in the UE may mean providing information such as the identification of the control resource set, the frequency position of the control resource set, and the symbol length of the control resource set. For example, the higher layer signaling may include the information in Table 6 below, but is certainly not limited to the following examples.

[0168] [Table 6]

[0169]

[0170]

[0171]

[0172] In Table 6, the tci-StatesPDCCH (abbreviated as transmission configuration indication (TCI) state) configuration information may include information about one or more SS / PBCH block indices or channel state information reference signal (CSI-RS) indices that have a quasi co-location (QCL) relationship with the DMRS sent in the corresponding control resource set.

[0173] Next, downlink control information (DCI) in the 5G system will be described in detail.

[0174] In a 5G system, scheduling information for uplink data (or physical uplink data channel (physical uplink shared channel (PUSCH)) or downlink data (or physical downlink data channel (physical downlink shared channel (PDSCH)) can be sent from a base station to a UE via DCI. Alternatively, the UE can monitor a fallback DCI format and a non-fallback DCI format for PUSCH or PDSCH. The fallback DCI format may be composed of fixed fields predefined between the base station and the UE, and the non-fallback DCI format may include configurable fields. In addition, DCI has various formats, and each format may indicate whether it is a DCI for power control, a DCI for notifying a slot format indicator (SFI), and the like.

[0175] DCI can be sent through a physical downlink control channel (PDCCH) after a channel coding and modulation process. A cyclic redundancy check (CRC) can be added to the DCI message payload and can be scrambled with a radio network temporary identifier (RNTI) corresponding to the UE's identity. Different RNTIs can be used depending on the purpose of the DCI message, such as UE-specific data transmission, power control commands, or random access responses. That is, the RNTI is not explicitly sent, but is included in the CRC calculation process and is therefore sent. If the UE receives a DCI message sent via the PDCCH, the UE can identify the CRC through the assigned RNTI, and if the CRC is determined to be correct based on the CRC identification result, it can be discerned that the received DCI message has been sent to the UE. PDCCH can be mapped and sent in a control resource set (CORESET) for the UE.

[0176] For example, the DCI for scheduling the PDSCH for system information (SI) may be scrambled with the SI-RNTI. The DCI for scheduling the PDSCH for the random access response (RAR) message may be scrambled with the RA-RNTI. The DCI for scheduling the PDSCH for the paging message may be scrambled with the P-RNTI. The DCI for notifying the slot format indicator (SFI) may be scrambled with the SFI-RNTI. The DCI for notifying the transmit power control (TPC) may be scrambled with the TPC-RNTI. The DCI for scheduling the UE-specific PDSCH or PUSCH may be scrambled with the cell RNTI (C-RNTI). Of course, the type of RNTI is not limited to the above examples.

[0177] DCI format 0_0 may be used for fallback DCI used for scheduling PUSCH, in which case the CRC may be scrambled with the C-RNTI. The DCI format 0_0 in which the CRC is scrambled by the C-RNTI may include, for example, the following information, but is certainly not limited to the above example.

[0178] [Table 7]

[0179]

[0180] DCI format 0_1 ​​may be used for non-fallback DCI used for scheduling PUSCH, in which case the CRC may be scrambled with the C-RNTI. The DCI format 0_1 ​​in which the CRC is scrambled by the C-RNTI may include, for example, the following information, but is certainly not limited to the above example.

[0181] [Table 8]

[0182]

[0183]

[0184] DCI format 1_0 may be used for fallback DCI used for scheduling PDSCH, in which case the CRC may be scrambled with the C-RNTI. The DCI format 1_0 in which the CRC is scrambled by the C-RNTI may include, for example, the following information, but is certainly not limited to the above example.

[0185] [Table 9]

[0186]

[0187] DCI format 1_1 may be used for non-fallback DCI for scheduling PUSCH, in which case the CRC may be scrambled with the C-RNTI. The DCI format 1_1 in which the CRC is scrambled by the C-RNTI may include, for example, the following information, but is certainly not limited to the above example.

[0188] [Table 10]

[0189]

[0190]

[0191] For example, each control information included in DCI format 1_1 as scheduling control information (DL grant) of DL data may include the following information, but is of course not limited to the following examples.

[0192] - Carrier indicator: It indicates the carrier on which the data scheduled by the DCI is transmitted - 0 or 3 bits

[0193] - Identifier of DCI format: It indicates the DCI format, and in particular, it is an indicator to distinguish whether the corresponding DCI is for DL ​​or UL. - [1] bit

[0194] - Bandwidth Part Indicator: It indicates the change of bandwidth part (if any) - 0, 1 or 2 bits

[0195] - Frequency domain resource allocation: It is resource allocation information indicating frequency domain resource allocation. The indicated resources vary depending on whether the resource allocation type is 0 or 1.

[0196] -Time domain resource allocation: It is the resource allocation information indicating the time domain resource allocation. This can indicate a predefined PDSCH time domain resource allocation list or a configuration of higher layer signaling. -1, 2, 3 or 4 bits

[0197] - VRB to PRB mapping: It indicates the mapping relationship between virtual resource blocks (VRBs) and physical resource blocks (PRBs) - 0 or 1 bit

[0198] -PRB bundling size indicator: It indicates the size of the physical resource block bundling assuming the same precoding is applied. -0 or 1 bit

[0199] - Rate Matching Indicator: It indicates which rate matching group is applied among the rate matching groups configured via a higher layer applied to PDSCH - 0, 1 or 2 bits

[0200] -ZP CSI-RS trigger: It triggers the zero power channel state information reference signal - 0, 1 or 2 bits

[0201] - Transport Block (TB) related configuration information: It indicates the modulation and coding scheme (MCS), new data indicator (NDI) and redundancy version (RV) used for one or two TBs

[0202] - Modulation and Coding Scheme (MCS): It indicates the coding rate and modulation scheme used for data transmission. In other words, it may indicate the coding rate value, which may indicate TBS and channel coding information as well as information about whether it is QPSK, 16QAM, 64QAM or 256QAM

[0203] - New Data Indicator: It indicates whether it is a HARQ initial transmission or a retransmission.

[0204] - Redundancy Version: It indicates the redundancy version of HARQ.

[0205] -HARQ process number: It indicates the HARQ process number applied to PDSCH - 4 bits

[0206] - Downlink allocation index: Index used to generate dynamic HARQ-ACK codebook when reporting HARQ-ACK for PDSCH - 0 or 2 or 4 bits

[0207] - TPC command for scheduled PUCCH: Power control information for PUCCH applied to HARQ-ACK reporting for PDSCH - 2 bits

[0208] -PUCCH resource indicator: Information indicating the resource of the PUCCH used for HARQ-ACK reporting of PDSCH - 3 bits

[0209] -PDSCH-to-HARQ_feedback timing indicator: Configuration information for the time slot of the PUCCH in which the HARQ-ACK report for the PDSCH is transmitted - 3 bits

[0210] - Antenna port: Information indicating the antenna port of the PDSCH DMRS and the DMRS CDM group in which the PDSCH is not transmitted - 4, 5 or 6 bits

[0211] - Transmission configuration indication: Information indicating beam-related information of PDSCH - 0 or 3 bits

[0212] -SRS request: Information requesting SRS transmission - 2 bits

[0213] -CBG transmission information: Information indicating which code block group (CBG) data is sent via PDSCH when code block group-based retransmission is configured - 0, 2, 4, 6 or 8 bits

[0214] -CBG flush information: Information indicating whether the code block group previously received by the UE can be used for HARQ combining - 0 or 1 bit

[0215] -DMRS sequence initialization: It indicates the DMRS sequence initialization parameter - 1 bit

[0216] Hereinafter, a method for allocating time domain resources for a data channel in a 5G communication system will be described.

[0217] Downlink data may be sent on the PDSCH, which is a physical channel for downlink data transmission. Uplink data may be sent on the PUSCH, which is a physical channel for uplink data transmission. The PDSCH may be sent after the control channel transmission time, and scheduling information such as a specific mapping position in the frequency domain and a modulation method is determined based on the DCI sent through the PDCCH.

[0218] The base station may configure a table of time domain resource allocation information for a downlink data channel (PDSCH) and an uplink data channel (PUSCH) to the UE using higher layer signaling (e.g., RRC signaling). For PDSCH, a table consisting of a maximum number of entries may be configured, maxNrofDL-Allocations=16, and for PUSCH, a table consisting of a maximum number of entries may be configured, maxNrofUL-Allocations=16. The time domain resource allocation information may include, for example, PDCCH to PDSCH slot timing (which is designated as K0 and corresponds to the time interval between the reception time point of the PDCCH and the transmission time point of the PDSCH scheduled by the received PDCCH) or PDCCH to PUSCH slot timing (which is designated as K2 and corresponds to the time interval between the reception time point of the PDCCH and the transmission time point of the PUSCH scheduled by the received PDCCH), information on the position and length of the starting symbol for scheduling PDSCH or PUSCH in the slot, and the mapping type of PDSCH or PUSCH, etc. For example, the base station may notify the UE of information as shown in the following Tables 11 and 12, but is of course not limited to the following examples.

[0219] [Table 11]

[0220]

[0221]

[0222] [Table 12]

[0223]

[0224] The base station may notify the UE of one of the entries in the table for time domain resource allocation information via L1 signaling (e.g., DCI) (e.g., it may be indicated by a "time domain resource allocation" field in the DCI). The UE may obtain the time domain resource allocation information for the PDSCH or PUSCH based on the DCI received from the base station.

[0225] According to an embodiment of the present disclosure, time domain resource allocation may be transmitted via information about the time slot in which PDSCH / PUSCH is transmitted, the starting symbol position S in the corresponding time slot, and the number of symbols to which PDSCH / PUSCH is mapped L. Here, S may be a relative position from the start of the time slot, L may be the number of consecutive symbols, and S and L may be determined based on a start and length indicator value (SLIV) as defined in Equation 1 below.

[0226] [Equation 1]

[0227] If (L-1)≤7, then

[0228] SLIV=14·(L-1)+S

[0229] otherwise

[0230] SLIV=14·(14-L+1)+(14-1-S)

[0231] Among them, 0 <L≤14-S

[0232] In the NR system, the PDSCH mapping type is defined by type A and type B. In PDSCH mapping type A, the first symbol in the DMRS symbol can be located at the second or third OFDM symbol in the time slot. In PDSCH mapping type B, the first symbol in the DMRS symbol can be located at the first OFDM symbol in the time domain resources allocated via PUSCH transmission.

[0233] Through the modulation coding scheme (MCS) in the control information composed of DCI, the base station can notify the UE of the modulation scheme applied to the PDSCH to be transmitted and the size of the data to be transmitted (transport block size (TBS)). According to an embodiment of the present disclosure, the MCS may be composed of 5 bits or more or less. Before channel coding for error correction is applied to the data, the TBS may correspond to the size of the data (transport block (TB)) that the base station expects to transmit.

[0234] In the present disclosure, a transport block (TB) may include a media access control (MAC) header, a MAC control element (CE), one or more MAC service data units (SDUs), and padding bits. Alternatively, a TB may indicate a data unit or a MAC protocol data unit (PDU) delivered from the MAC layer to the physical layer.

[0235] The modulation schemes supported by the NR system are quadrature phase shift keying (QPSK), 16-quadrature amplitude modulation (16QAM), 64QAM and 256QAM, and the modulation orders (Q m ) correspond to 2, 4, 6 and 8 respectively. That is, 2 bits can be sent per symbol in the case of QPSK modulation, 4 bits can be sent per symbol in the case of 16QAM modulation, 6 bits can be sent per symbol in the case of 64QAM modulation, and 8 bits can be sent per symbol in the case of 256QAM modulation.

[0236] In order to explain the methods and devices proposed in the embodiments of the present disclosure, the terms of physical channels and signals in the NR system may be used. However, the details of the present disclosure may be applied to wireless communication systems other than the NR system.

[0237] In the present disclosure, downlink (DL) is a wireless transmission path of a signal transmitted by a base station to a UE, and uplink (UL) refers to a wireless transmission path of a signal transmitted by a UE to a base station.

[0238] In the present disclosure, the terms of physical channels and signals may be used interchangeably with data or control signals. For example, PDSCH is a physical channel through which data is transmitted, but in the present disclosure, PDSCH may be referred to as data.

[0239] Hereinafter, in the present disclosure, higher layer signaling is a signal delivery method of sending a signal from a base station to a UE using a downlink data channel of a physical layer, or a signal delivery method of sending a signal from a UE to a base station using an uplink data channel of a physical layer, and the higher layer signaling may be referred to as RRC signaling or a MAC control element (CE).

[0240] According to an embodiment of the present disclosure, a timing advance (TA) may be sent via a MAC control element (CE), such as a timing advance command MAC CE, an absolute timing advance command MAC CE, and the like.

[0241] On the other hand, a message delivered from the MAC layer to the physical layer, such as a MAC PDU, may include one or more MAC subPDUs. Each MAC subPDU in the MAC subPDU may include one of the following information, but is certainly not limited to the following examples.

[0242] - MAC subheader only (including padding)

[0243] -MAC subheader and MAC SDU

[0244] -MAC subheader and MAC CE

[0245] -MAC subheader and padding

[0246] The MAC SDU has a variable size, and each MAC subheader can correspond to a MAC SDU, a MAC CE, or padding.

[0247] On the other hand, messages delivered from the MAC layer to the physical layer, such as MAC PDUs, can be respectively as follows in the case of downlink and uplink: Figure 5 and Figure 6 As shown.

[0248] First, refer to Figure 5 An example of a message delivered from a MAC layer to a physical layer in a downlink in a communication system according to various embodiments of the present disclosure is described.

[0249] Figure 5is a diagram schematically illustrating an example of a message delivered from a MAC layer to a physical layer in a downlink in a communication system according to an embodiment of the present disclosure.

[0250] refer to Figure 5 An example of a message delivered from the MAC layer to the physical layer in the downlink may be a downlink MAC PDU (DL MAC PDU). Figure 5 , a MAC sub-PDU 500 including a MAC CE 1 may include an R / LCID sub-header 502 and a fixed-size MAC CE 504, and a MAC sub-PDU 510 including a MAC CE 2 may include an R / F / LCID / L sub-header 512 and a variable-size MAC CE 514. Also, a MAC sub-PDU 520 including a MAC SDU may include an R / F / LCID / L sub-header 522 and a MAC SDU 524.

[0251] exist Figure 5 In the LCID field, LCID represents the logical channel ID field. The LCID field indicates the instance of the corresponding MAC SDU, the type of the corresponding MAC CE, or padding. This will be described in detail in Tables 13 and 14 below. Here, Table 13 below shows the LCID value for DL-SCH, and Table 14 shows the LCID value for UL-SCH.

[0252] [Table 13]

[0253]

[0254]

[0255] [Table 14]

[0256]

[0257] There is one LCID field for each MAC subheader, and the size of the LCID field is 6 bits. In the case where the LCID field is configured as, for example, "34", one additional octet exists in the MAC subheader including the eLCID field and follows the octet including the LCID field. In the case where the LCID field is configured as, for example, "33", two additional octets exist in the MAC subheader including the eLCID field and follow the octet including the LCID field.

[0258] Also, eLCID represents an extended logical channel ID field, and indicates a logical channel instance of a corresponding MAC SDU or a type of a corresponding MAC CE. The size of the eLCID field is 8 bits or 16 bits.

[0259] Moreover, L represents a length field, and the length field indicates the length of the corresponding MAC SDU or a variable-sized MAC CE. There is one length field for each MAC subheader except for a subheader corresponding to a MAC SDU including a fixed-sized MAC CE, padding, or a UL common control channel (CCCH). The size of the length field is indicated by the F field.

[0260] Moreover, F represents the format field and indicates the size of the length field. There is one F field for each MAC subheader except for the MAC SDU including the fixed-size MAC CE, padding, and UL CCCH. The size of the F field is 1 bit. For example, a value of 0 indicates an 8-bit length field. As another example, a value of 1 indicates a 16-bit length field.

[0261] Also, R is a reserved bit, and is configured to, for example, "0".

[0262] like Figure 5 As shown, MAC CEs (e.g., MAC CE1 and MAC CE2) are arranged together, and (multiple) MAC sub-PDUs including (multiple) MAC CEs are arranged before the MAC sub-PDUs including the MAC SDU and the MAC sub-PDUs including padding. The size of the padding may be zero.

[0263] Next, we will refer to Figure 6 An example of a message delivered from a MAC layer to a physical layer in an uplink in a communication system according to various embodiments of the present disclosure is described.

[0264] Figure 6 is a diagram schematically illustrating an example of a message delivered from a MAC layer to a physical layer in an uplink in a communication system according to an embodiment of the present disclosure.

[0265] refer to Figure 6 An example of a message delivered from the MAC layer to the physical layer in the uplink may be an uplink MAC PDU (UL MAC PDU). Figure 6 , a MAC sub-PDU 610 including a MAC CE 1 includes an R / LCID sub-header 612 and a fixed-size MAC CE 614, and a MAC sub-PDU 620 including a MAC CE 2 includes an R / F / LCID / L sub-header 622 and a variable-size MAC CE 624. Moreover, a MAC sub-PDU 600 including a MAC SDU includes an R / F / LCID / L sub-header 602 and a MAC SDU 604.

[0266] like Figure 6As shown, MAC CE (e.g., MAC CE1 and MAC CE2) are arranged together, and (multiple) MAC sub-PDUs including (multiple) MAC CEs are arranged after the MAC sub-PDU including the MAC SDU and before the MAC sub-PDU including the padding. Here, the size of the padding can be zero.

[0267] exist Figure 5 and Figure 6 In the subheader of the MAC layer, the LCID, i.e., the logical channel ID or the extended logical channel ID (eLCID), may indicate the type of the MAC SDU or MAC CE to be sent. The mapping between the index of the LCID, the type of the MAC SDU or MAC CE, etc. may be shown in Table 13 below, and the mapping between the index of the eLCID, the type of the MAC SDU or MAC CE, etc. may be shown in Table 14 below. In various embodiments of the present disclosure, the LCID may indicate an instance of a logical channel of a MAC SDU, a type of MAC CE, or padding information of a downlink shared channel (DL-SCH) and an uplink shared channel (UL-SCH). One LCID may be mapped to each MAC subheader, and the LCID may be implemented with, for example, 6 bits.

[0268] Figure 7 is a diagram illustrating an example of a process of dividing one transport block (TB) into a plurality of code blocks (CBs) and adding a CRC according to an embodiment of the present disclosure.

[0269] refer to Figure 7 , CRC 703 can be added to the last or front part of a transport block (TB) 701 to be sent in the uplink or downlink. CRC 703 can have 16 bits, 25 bits, pre-fixed bits, or can have a variable number of bits according to channel conditions, and can be used to determine whether channel coding is successful. The block in which CRC 703 is added to TB 701 can be divided into multiple code blocks (CB) 707, 709, 711 and 713 (705). According to an embodiment of the present disclosure, the code blocks can be divided with a preset maximum size. In this case, the size of the last code block 713 can be smaller than the size of other code blocks 707, 709 and 711. However, this is only an example. When 0, a random value or 1 can be inserted into the last code block 713, the length of the last code block 713 can become equal to the length of other code blocks 707, 709 and 711.

[0270] Also, CRCs 717, 719, 721, and 723 may be added to code blocks 707, 709, 711, and 713, respectively (715). CRC may have 16 bits, 24 bits, or pre-fixed bits, and may be used to determine whether channel coding is successful.

[0271] CRC 703 may be generated using TB 701 and a cycle generator polynomial, and the cycle generator polynomial may be defined in various ways. For example, assuming that for a 24-bit CRC, the cycle generator polynomial gCRC24A(D)=D 24 +D 23 +D 18 +D 17 +D 14 +D 11 +D 10 +D 7 +D 6 +D 5 +D 4 +D 3 +D+1, when L=24, for TB data a 0 、a 1 、a 2 、a 3 , ..., a A-1 CRCp 0 、p 1 、p 2 、p 3 , ..., p L-1 is when a 0 D A+23 +a 1 D A+22 +...+a A-1 D 24 +p 0 D 23 +p 1 D 22 +...+p 22 D 1 +p 23 The remainder becomes 0 when divided by gCRC24A(D), and p can be determined 0 、p 1 、p 2 、p 3 , ..., p L-1 The above example has been described under the assumption that the CRC length L is 24, but the CRC length L may be determined in various ways, for example, as 12, 16, 24, 32, 40, 48, 64, etc.

[0272] After the CRC is added to the TB by this process, the TB+CRC may be divided into N CBs 707, 709, 711, and 713. CRCs 717, 719, 721, and 723 may be added to the divided CBs 707, 709, 711, and 713 (715), respectively. The CRC added to the CB may have a different length from when the CRC added to the TB is generated, or a different cyclic generator polynomial may be used to generate the CRC. Moreover, depending on the type of channel code to be applied to the code block, the CRC 703 added to the TB and the CRCs 717, 719, 721, and 723 added to the code block may be omitted. For example, in the case where a low-density parity check (LDPC) code is applied to the code block instead of a turbo code, the CRCs 717, 719, 721, and 723 to be inserted for each code block may be omitted.

[0273] However, even in the case of applying LDPC, CRC 717, 719, 721, and 723 may be added to the code block as it is. Also, in the case of using a polar code, CRC may be added or omitted.

[0274] As referenced above Figure 7 As described, in a TB to be transmitted, a maximum length of one code block may be determined according to a type of channel coding applied, and division of the TB and a CRC added to the TB into code blocks may be performed according to the maximum length of the code block.

[0275] In the conventional LTE system, a CRC for a CB is added to the divided CB, the CRC and data bits of the CB are encoded with a channel code, and the coded bits are determined. For each coded bit, the number of rate-matched bits is determined as prearranged.

[0276] The size of TB (TBS) in the NR system can be calculated by the following operations.

[0277] Operation 1: Calculate N′ RE , which is the number of REs allocated to PDSCH mapping in one PRB within the allocated resources. N' RE can be calculated as here, It is 12. The number of OFDM symbols allocated to the PDSCH may be indicated. It is the number of REs in one physical resource block (PRB) occupied by DMRS of the same code division multiple access (CDM) group. is the number of REs occupied by overhead in one PRB configured by higher layer signaling and can be configured as one of 0, 6, 12 or 18. After that, the total number of REs allocated to PDSCH, N, can be calculated.RE . N RE Calculated as N RE =min(156,N′ RE )·n PRB , and n PRB Indicates the number of PRBs allocated to the UE.

[0278] Operation 2: Number of temporary information bits N info can be calculated as N RE ×R×Q m ×v, R is the bit rate, Q m is the modulation order, and information about the value can be transmitted by using the MCS bit field of the DCI and a pre-arranged table. Also, v is the number of allocated layers. When N info When ≤3824, TBS can be calculated by operation 3 below. Otherwise, TBS can be calculated by operation 4.

[0279] Operation 3: N′ info Can be and TBS can be determined as not less than N' in Table 15 below. info The value closest to N′ info The value of .

[0280] [Table 15]

[0281]

[0282]

[0283] Operation 4: N′ info Can be and TBS can be calculated by the following N′ info and [Pseudo Code 1] to determine. In the following, C corresponds to the number of code blocks included in one TB.

[0284] [Begin pseudo code 1]

[0285]

[0286] [End of pseudocode 1]

[0287] In the NR system, when a CB is input to the LDPC encoder, parity bits may be added and output. In this case, the amount of parity bits may vary according to the LDPC base graph. The method for sending all parity bits generated by LDPC encoding on a specific input may be referred to as full buffer rate matching (FBRM), and the method for limiting the number of parity bits that can be sent may be referred to as limited buffer rate matching (LBRM). When resources are allocated for data transmission, the LDPC encoder output is generated into a circular buffer, and the bits of the generated buffer are repeatedly sent as many times as the allocated resources. In this case, the length of the circular buffer may be N. cb .

[0288] When the number of all parity bits generated by LDPC coding is N, N in FBRM cb = N. In LBRM, N cb =min(N,N ref ), N ref Depend on Given, R LBRM can be determined as 2 / 3. In order to obtain TBS LBRM , using the method for obtaining TBS. Assume that the UE supports the maximum number of layers and the maximum modulation order in the corresponding cell. Assume that the maximum modulation order Q is Q when the corresponding cell is configured to use an MCS table that supports 256QAM for at least one BWP. m is 8, and if not configured, the maximum modulation order is 6 (64QAM). The code rate is assumed to be 948 / 1024, which is the maximum code rate. RE Assumed to be 156n PRB .n PRB It is assumed to be n PRB,LBRM And calculate. PRB,LBRM It can be given as shown in Table 16 below.

[0289] [Table 16]

[0290]

[0291] In the NR system, the maximum data rate supported by the UE can be determined by the following equation 2.

[0292] [Equation 2]

[0293]

[0294] In Equation 2, J may be the number of carriers aggregated by frequency aggregation, and R max =948 / 1024, Can be the maximum number of layers, can be the maximum modulation order, f (j) can be a scaling factor, and μ can be the SCS. (j) The UE may be allowed to report one of 1, 0.8, 0.75, and 0.4, and μ may be given as shown in Table 17 below.

[0295] [Table 17]

[0296]

[0297]

[0298] and, is the average OFDM symbol duration, can be calculated as is the maximum number of RBs in BW(j). (j) is an overhead value and can be given as 0.14 in the downlink of FR1 (frequency band below 6 GHz) and 0.18 in the uplink of FR1, and can be given as 0.08 in the downlink of FR2 and 0.10 in the uplink of FR2. The maximum data rate in the downlink in a cell with a frequency bandwidth of 100 MHz at an SCS of 30 kHz can be calculated by Equation 2 as shown in Table 18 below.

[0299] [Table 18]

[0300]

[0301] On the other hand, the actual data rate that can be measured in the actual data transmission of the UE can be a value obtained by dividing the amount of data by the data transmission time. This can be a value obtained by dividing the sum of the TBS in 1 TB transmission or the TBS in 2 TB transmission by the TTI duration. For example, as in the assumption of obtaining Table 15, the maximum actual data rate in the downlink in a cell with a frequency bandwidth of 100 MHz at an SCS of 30 kHz can be determined according to the number of allocated PDSCH symbols, as shown in Table 19 below.

[0302] [Table 19]

[0303]

[0304] The maximum data rate supported by the UE can be confirmed through Table 18, and the actual data rate according to the allocated TBS can be confirmed through Table 16. In this case, according to scheduling information, there may be a case where the actual data rate is greater than the maximum data rate.

[0305] In wireless communication systems, especially in new radio (NR) systems, the data rate that a UE can support can be mutually agreed upon between a base station and the UE. This can be calculated using the maximum frequency band, maximum modulation order, maximum number of layers, etc. supported by the UE. However, the calculated data rate may be different from the value calculated from the transport block size (TBS) and the transmission time interval (TTI) duration used for actual data transmission.

[0306] Therefore, the UE may be allocated a TBS greater than a value corresponding to the data rate supported by the UE. To prevent this, the TBS that can be scheduled according to the data rate supported by the UE may be limited.

[0307] Since the UE is usually spaced apart from the base station, the signal sent by the UE is received by the base station after the propagation delay. The propagation delay is a value obtained by dividing the propagation path from the UE to the base station by the speed of light, and may be a value obtained by dividing the distance from the UE to the base station by the speed of light. In an embodiment, when the UE is 100km apart from the base station, the signal sent by the UE is received by the base station after approximately 0.34 milliseconds. In contrast, the signal sent by the base station is received by the UE after approximately 0.34 milliseconds. As described above, the time at which the signal sent by the UE arrives at the base station may be different depending on the distance between the UE and the base station. Therefore, when multiple UEs present in different locations send signals at the same time, the time at which the signal arrives at the base station may all be different. In order to enable the signals sent by multiple UEs to arrive at the base station at the same time by solving this problem, the time at which the uplink signal is sent may be determined to be different according to the location of the UE. In 5G, NR and LTE systems, this is called timing advance (TA).

[0308] Figure 8 is a schematic diagram showing a processing time of a UE according to a timing advance when the UE receives a first signal and sends a second signal in response to the first signal in a 5G or NR system according to an embodiment of the present disclosure.

[0309] When the base station transmits a first signal (uplink scheduling grant (UL grant) or downlink control signal and data (DL grant and DL data)) to the UE in time slot n 802, the UE may receive the first signal in time slot n 804. In this case, the UE may be later than the time when the base station transmits the signal by a propagation delay (T p)810 receives a signal. According to an embodiment, in the case where the UE receives the first signal in time slot n804, the UE sends a corresponding second signal (HARQ-ACK / NACK for uplink data or downlink data) in time slot n+4 806. When the UE sends a signal to the base station, the UE may send the second signal at a timing 806 that is earlier than the time slot n+4 in which the UE receives the signal by a timing advance (TA) 812 so that the signal arrives at the base station at a specific time. Therefore, in an embodiment, the time when the UE is ready to receive an uplink scheduling grant, send uplink data or receive downlink data, and send HARQ ACK or NACK may be a time obtained by subtracting TA from the time corresponding to 3 time slots (814).

[0310] In order to determine the timing as described above, the base station may calculate the absolute value of the TA corresponding to the UE. When the UE initially accesses, the base station may calculate the absolute value of the TA while adding the amount of change in the TA value subsequently sent through higher layer signaling to the TA value initially sent to the UE in the random access step, or subtracting the amount of change in the TA value subsequently sent through higher layer signaling from the TA value initially sent to the UE. In the present disclosure, the absolute value of the TA may be a value obtained by subtracting the start time of the nth TTI received by the UE from the start time of the nth TTI sent by the UE.

[0311] At the same time, one of the important references for the performance of a cellular wireless communication system is packet data latency. To this end, in an LTE system, signals are sent and received in units of subframes with a transmission time interval (hereinafter referred to as TTI) of 1 ms. In an LTE system operating as described above, UEs with a TTI shorter than 1 ms (short TTI UEs) can be supported. At the same time, in a 5G or NR system, the TTI can be shorter than 1 ms. Short TTI UEs are suitable for services such as LTE voice (VoLTE) and remote control where latency is important. In addition, short TTI UEs can be devices for implementing mission-critical cellular-based Internet of Things (IoT).

[0312] In a 5G or NR system, when a base station transmits a PDSCH including downlink data, the DCI for scheduling the PDSCH indicates a K1 value, which is a value corresponding to information about the timing of the HARQ-ACK information that the UE transmits the PDSCH. In the case where the transmission of HARQ-ACK information including timing advance earlier than symbol L1 is not indicated, the UE can send HARQ-ACK information to the base station. That is, the HARQ-ACK information can be sent from the UE to the base station at the same or later time point (including timing advance) as symbol L1. In the case of indicating the transmission of HARQ-ACK information including timing advance earlier than symbol L1, the HARQ-ACK information may not be HARQ-ACK information valid for HARQ-ACK transmission from the UE to the base station.

[0313] Symbol L1 may be a cyclic prefix (CP) at the last time point T from the PDSCH. proc,1 The first symbol after that. T proc,1 It can be calculated as shown in Equation 3 below.

[0314] [Equation 3]

[0315] T proc,1 =(N 1 +d 1,1 )(2048+144)·κ2 -μ ·T C

[0316] In the above equation 3, N 1 ,d 1,1 ,d 1,2 , k, μ, T C It can be defined as follows.

[0317] -When HARQ-ACK information is sent via PUCCH (Uplink Control Channel), d 1,1 = 0, and when HARQ-ACK information is sent through PUSCH (uplink shared channel, data channel), d 1,1 =1

[0318] - In the case where the UE receives a configuration of multiple activated component carriers or carriers, the maximum timing difference between the carriers may be reflected in the second signal transmission

[0319] - In the case of PDSCH mapping type A, that is, in the case where the first DMRS symbol position is the third or fourth symbol in the slot, when the position index i of the last symbol of the PDSCH is less than 7, d 1,2 =7-i.

[0320] - In the case of PDSCH mapping type B, that is, in the case where the first DMRS symbol position is the first symbol of the PDSCH, when the length of the PDSCH is 4 symbols, d 1,2 =3, when the length of PDSCH is 2 symbols, d 1,2 =3+d, and d is the number of symbols in which the PDSCH overlaps with the PDCCH including a control signal for scheduling the corresponding PDSCH.

[0321] -N 1 According to the definition of μ, as shown in Table 20 below, μ = 0, 1, 2, 3 means the subcarrier spacing is 15kHz, 30kHz, 60kHz and 120kHz

[0322] [Table 20]

[0323]

[0324] N provided by Table 20 above 1 The values ​​may vary depending on UE capabilities and are defined as follows.

[0325] T c =1 / (Δf max -N f ), Δf max =480·10 3 Hz,N f =4096,κ=T s / T c =64, T s =1 / (Δf ref ·N f，ref )

[0326] Δf ref =15·10 3 Hz,N f,ref =2048

[0327] Moreover, in a 5G or NR system, when a base station transmits control information including an uplink scheduling grant, a K2 value corresponding to information about the timing at which the UE transmits uplink data or a PUSCH may be indicated.

[0328] In the case where the transmission of the PUSCH including the timing advance earlier than the symbol L2 is not indicated, the UE may send the PUSCH to the base station. That is, the PUSCH may be sent from the UE to the base station at the same or later time point (including the timing advance) as the symbol L1. In the case where the transmission of the PUSCH including the timing advance earlier than the symbol L2 is indicated, the UE may ignore the uplink scheduling grant control information from the base station.

[0329] Symbol L2 may be the first symbol of the CP of a PUSCH symbol, which needs to be at the last time point T from the last PDCCH including the scheduling grant. proc,2 Then send. proc,2 It can be calculated as shown in Equation 4 below.

[0330] [Equation 4]

[0331] T proc,2 =((N 2 +d 2，1 )(2048+144)·κ2 -μ )·T C

[0332] In Equation 4 above, N 2 ,d 2,1 ,κ,μ,T C It can be defined as follows.

[0333] -When the first symbol among the symbols to which the PUSCH is allocated includes only the DMRS, d 2,1 =0, otherwise, d 2,1 =1.

[0334] - When the UE receives a configuration of multiple activated component carriers or carriers, the maximum timing difference between the carriers may be reflected in the second signal transmission

[0335] -N 2 According to the definition of μ, as shown in Table 21 below, μ = 0, 1, 2, 3 means the subcarrier spacing is 15kHz, 30kHz, 60kHz and 120kHz

[0336] [Table 21]

[0337] μ <![CDATA[PUSCH preparation time N 2 [Symbol]]]> 0 10 1 12 2 23

[0338] - N provided by Table 21 above 2 The value may vary depending on UE capabilities.

[0339] T c =1 / (Δf max ·N f ), Δf max =480·10 3 Hz,N f =4096,κ=T s / T c =64, T s =1 / (△f ref ·N f，ref )

[0340] Δf ref =15·103 Hz,N f,ref =2048

[0341] And are defined as above respectively.

[0342] At the same time, the 5G or NR system can configure a frequency bandwidth part (BWP) within a carrier and specify transmission and reception by a specific UE within the configured BWP. This is to reduce the power consumption of the UE. The base station can configure multiple BWPs and change the activated BWP in the control information. The time for the UE to change the BWP can be defined as shown in Table 22 below.

[0343] [Table 22]

[0344]

[0345] In Table 22, frequency range FR1 may refer to a frequency band equal to or lower than 6 GHz, and frequency range FR2 may refer to a frequency band higher than or equal to 6 GHz, and may be classified as shown in Table 4 above. In general, FR2 may refer to a high frequency band close to the mmWave band, and FR1 may refer to a relatively lower frequency band compared to FR2. In the above embodiment, type 1 and type 2 may be determined according to UE capabilities. In the above embodiment, scenarios 1, 2, 3, and 4 are shown in Table 23 below.

[0346] [Table 23]

[0347]

[0348] Fig. 9 is a schematic diagram showing an example of scheduling and sending data (eg, TB) according to time slots, receiving HARQ-ACK feedback of the corresponding data, and performing retransmission according to the feedback.

[0349] exist Fig. 9 , TB1 900 is initially transmitted in time slot 0 902, and ACK / NACK feedback 904 for the TB1 is transmitted in time slot 4 906. If the initial transmission of TB1 fails and a NACK is received, a retransmission 910 of TB1 may be performed in time slot 8 908. The time point at which the ACK / NACK feedback is transmitted and the time point at which the retransmission is performed may be predetermined or may be determined according to control information and / or a value indicated by higher layer signaling.

[0350] Fig. 9An example is shown in which TB1 to TB8 are scheduled and transmitted in sequence according to the time slot from time slot number 0. This may mean transmission of TB1 to TB8 to which HARQ process IDs 0 to 7 are allocated. If the number of HARQ process IDs that the base station and UE can use is only 4, transmission for 8 different TBs may be performed discontinuously.

[0351] Fig.10 is a schematic diagram illustrating an example of a communication system using a satellite according to an embodiment of the present disclosure.

[0352] For example, when UE (very small aperture terminal (VSAT)) 1001 transmits a signal to satellite 1003 through a service link, satellite (onboard platform) 1003 may transmit a signal to base station 1005 through a feeder link, and base station 1005 may process the received signal and transmit a signal including a requirement for subsequent operation of the received signal to UE 1001, which may be transmitted again through satellite 1003. The distance between UE 1001 and satellite 1003 is long, and the distance between satellite 1003 and base station 1005 is also long, and therefore, the time taken for data transmission / reception from UE 1001 to base station 1005 may become longer.

[0353] Fig.11 is a schematic diagram illustrating the revolution period of a communication satellite around the earth according to the altitude or height of the satellite according to an embodiment of the present disclosure.

[0354] Depending on the satellite orbit, communication satellites may be classified into low earth orbit (LEO), medium earth orbit (MEO), geostationary orbit (GEO), etc. In general, GEO 1100 may refer to a satellite having an altitude of about 36,000 km, MEO 1110 may refer to a satellite having an altitude of 5,000 to 15,000 km, and LEO may refer to a satellite having an altitude of 500 to 1,000 km, but they are certainly not limited thereto.

[0355] According to an embodiment of the present disclosure, the revolution period around the earth varies depending on the altitude, and GEO 1100 has about 24 hours, MEO 1110 has about 6 hours, and LEO 1130 has about 90 to 120 minutes of revolution period around the earth. The advantage of a low-orbit (about 2,000 km) satellite is that it has a shorter propagation delay time (understood as the time it takes until a signal output from a transmitter reaches a receiver) and lower loss associated with a relatively low altitude than a geostationary orbit (36,000 km) satellite.

[0356] Fig.12 is a schematic diagram illustrating the concept of direct communication between a satellite and a UE according to an embodiment of the present disclosure.

[0357] A satellite 1200 located at a position higher than or equal to an altitude of 100 km via a rocket transmits and receives signals to and from a UE 1210 on the ground, and also transmits and receives signals to and from a ground station 1220 connected to a base station (DU plant) 1230 on the ground.

[0358] Fig.13 is a schematic diagram illustrating a scenario of using direct communication between a satellite and a UE according to an embodiment of the present disclosure.

[0359] Direct communication between a satellite and a UE can support dedicated communication services in a manner that compensates for coverage limitations of a terrestrial network. For example, by implementing the function of direct communication between a satellite and a UE in a UE, satellite communication can be used to enable the sending and receiving of emergency rescue or / and disaster signals for users outside the coverage of terrestrial network communications (1300), provide mobile communication services to users in areas where terrestrial network communications are not possible (such as on ships or / and airplanes) (1310), track and control the position of ships, trucks or / and drones in real time without boundary restrictions (1320), or perform backhaul functions in physically remote areas by supporting satellite communication functions in base stations and serving as backhaul for base stations (1330).

[0360] Fig.14 is a diagram illustrating an example of calculation of an expected data throughput in an uplink when a LEO satellite having an altitude of 1200 km and a UE perform direct communication according to an embodiment of the present disclosure.

[0361] In the case where the effective isotropic radiated power (EIRP) of the terrestrial UE in the uplink is 23dBm, the path loss of the radio channel to the satellite is 169.8dB, and the satellite receiving antenna gain is 30dBi, the achievable signal-to-noise ratio (SNR) is estimated to be -2.63dB. In this case, the path loss may include free space path loss, atmospheric path loss, etc. When the signal-to-interference ratio (SIR) is assumed to be 2dB, the signal-to-interference-to-noise ratio (SINR) is calculated to be -3.92dB, in which case a transmission rate of 112kbps can be achieved using a subcarrier spacing of 30kHz and a frequency resource of 1PRB.

[0362] Fig.15 is a diagram illustrating an example of calculation of an expected data throughput in an uplink when a GEO satellite having an altitude of 35,786 km and a ground UE perform direct communication according to an embodiment of the present disclosure.

[0363] In the case where the EIRP of the terrestrial UE in the uplink is 23dBm, the path loss of the radio channel to the satellite is 195.9dB, and the satellite receiving antenna gain is 51dBi, the achievable SNR is estimated to be -10.8dB. In this case, the path loss may include the path loss in space, the path loss in the atmosphere, etc. When the SIR is assumed to be 2dB, the SINR is calculated to be -11dB, in which case a transmission rate of 21kbps can be achieved using a subcarrier spacing of 30kHz and a frequency resource of 1PRB, which is the result of 3 repeated transmissions.

[0364] Fig.16 It is a schematic diagram showing a path loss value according to a path loss model between a UE and a satellite and a path loss according to a path loss model between a UE and a ground network communication base station according to an embodiment of the present disclosure.

[0365] exist Fig.16 Where d is the distance and fc is the frequency of the signal. The path loss 1600 (FSPL) in the free space where the communication between the UE and the satellite is performed is inversely proportional to the square of the distance, while the path loss 1610, 1620 (PL) on the ground where there is air and the communication between the UE and the ground network communication base station (ground gNB) is performed is inversely proportional to the square of the distance. 2 , PL' Uma-NLOS ) is inversely proportional to approximately the fourth power of the maximum distance. 3D It refers to the straight-line distance between UE and base station, h BS is the height of the base station, and h UT is the height of the UE. Calculate d' BP =4×h BS ×h UT ×f c / c. fc is the center frequency in Hz, and c is the speed of light in m / s.

[0366] In satellite communications (or non-terrestrial networks (NTN)), Doppler shift, i.e., the frequency shift (offset) of the transmitted signal, occurs due to the continuous and rapid movement of the satellite.

[0367] Fig.17 is a schematic diagram showing an equation for calculating the amount of Doppler shift experienced by a signal when a signal sent from a satellite is received by a user on the ground and its result according to an embodiment of the present disclosure, based on the altitude and position of the satellite and the position of the user of the UE on the ground.

[0368] The radius of the Earth is R, h is the altitude of the satellite, v is the speed of the satellite's revolution around the Earth, and fc is the frequency of the signal. The speed of the satellite can be calculated from the altitude of the satellite, which corresponds to the speed that makes the gravity (that is, the force that makes the Earth pull on the satellite) the same as the centripetal force generated by the satellite's revolution, and can be calculated as Fig.18 Calculated as shown.

[0369] Fig.18 is a schematic diagram showing the velocity of a satellite calculated at the altitude of the satellite. Fig.17 As indicated in , the angle α is determined by the elevation angle θ, and thus the value of the Doppler shift is determined according to the elevation angle θ.

[0370] Fig.19 is a schematic diagram showing Doppler frequency shift experienced by different UEs in a beam transmitted by a satellite to the ground according to an embodiment of the present disclosure.

[0371] exist Fig.19 , the Doppler shift experienced by UE1 1900 and UE2 1910 according to the elevation angle θ is calculated. It is a result of assuming that the center frequency is 2 GHz, the satellite altitude is 700 km, the radius of one beam on the ground is 50 km, and the speed of the UE is 0. In addition, the Doppler shift calculated in the present disclosure ignores the influence according to the rotation speed of the earth, which can be considered as a small influence because the rotation speed of the earth is very slow compared with the speed of the satellite.

[0372] Fig. 20 is a schematic diagram illustrating a difference between Doppler frequency shifts generated within one beam according to a position of a satellite determined by an elevation angle according to an embodiment of the present disclosure.

[0373] When the satellite is located directly above the beam, that is, when the elevation angle is 90 degrees, it can be seen that the difference between the Doppler shifts is the largest within the beam (or cell). This is because when the satellite is located at the top in the middle, the Doppler shift values ​​at one end and the other end of the beam have positive and negative values, respectively.

[0374] Meanwhile, due to the long distance between the satellite and the user on the ground in satellite communication, satellite communication has a longer delay time compared with terrestrial network communication.

[0375] Fig.21 is a schematic diagram illustrating a delay time from a UE to a satellite according to a position of a satellite determined by an elevation angle and a round-trip delay time between the UE, the satellite, and a base station according to an embodiment of the present disclosure.

[0376] The first graph 2100 shows the delay time from the UE to the satellite, and the second graph 2110 shows the round trip delay time between the UE, the satellite and the base station. In this case, it is assumed that the delay time between the satellite and the base station and the delay time between the UE and the satellite are the same as each other.

[0377] Fig. 22 is a schematic diagram illustrating a maximum difference in round-trip delay time depending on a position of a user within a beam according to an embodiment of the present disclosure.

[0378] For example, when the beam radius (or cell radius) is 20 km, the difference in round-trip delay time to the satellite experienced by UEs at different positions within the beam may be equal to or less than about 0.28 ms depending on the position of the satellite.

[0379] The transmission and reception of signals by the UE and the base station in satellite communication may mean transmitting the signals through the satellite. That is, the satellite may be used to receive a signal transmitted by the base station to the satellite and then transmit the signal to the UE in a downlink, and to receive a signal transmitted by the UE to the satellite and then transmit the signal to the base station in an uplink. The satellite may receive the signal and then transmit the signal after performing only frequency shift, or may perform signal processing such as decoding and re-encoding based on the received signal and then transmit the signal.

[0380] In the case of LTE or NR, the UE can access the base station through the following process.

[0381] - Operation 1: The UE receives a synchronization signal (or a synchronization signal block (SSB) including a broadcast signal) from a base station. The synchronization signal may include a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a physical broadcast channel (PBCH). The synchronization signal may include information about a time slot boundary, a frame number, a downlink, an uplink configuration, etc. of a signal sent by the base station. Further, through the synchronization signal, the UE may obtain a subcarrier offset, scheduling information for sending system information, etc.

[0382] - Operation 2: The UE receives system information (System Information Block (SIB)) from the base station. The SIB may include information for performing initial access and random access. The information for performing random access may include resource information for transmitting a random access preamble.

[0383] - Operation 3: Send a random access preamble (or message 1 (msg1)) in the random access resource configured in operation 2. The preamble may be a signal determined based on the information configured using a predetermined process in operation 2. The base station receives the preamble sent by the UE. The base station may attempt to receive the preamble configured in the resources configured by the base station without knowing which UE has sent the preamble, and when the reception is successful, it may be known that at least one UE has sent the preamble.

[0384] - Operation 4: When the preamble is received in operation 3, the base station sends a random access response (RAR) (or message 2 (msg2)), which corresponds to the response thereto. The UE that has sent the random access preamble in operation 3 may attempt to receive the RAR sent by the base station in this operation. The RAR is sent on the PDSCH, and the PDCCH for scheduling the PDSCH is sent together or in advance. The CRC scrambled by the RA-RNTI value is added to the DCI for scheduling the RAR, and the DCI (and CRC) is channel coded and then mapped to the PDCCH and sent. The RA-RNTI can be determined based on the time and frequency resources at which the preamble is sent in operation 3.

[0385] The maximum limit time until the UE that has transmitted the random access preamble in operation 3 receives the RAR may be configured in the SIB transmitted in operation 2. The maximum limit time may be constrained and configured to, for example, a maximum of 10 ms or 40 ms. That is, when the UE that transmits the preamble in operation 3 does not receive the RAR within a time determined based on, for example, the configured maximum time of 10 ms, the preamble may be transmitted again. The RAR may include scheduling information for allocating resources for a signal to be transmitted by the UE in operation 5, which is the following operation.

[0386] Fig.23 is a diagram showing an example of a (MAC payload) information structure of RAR according to an embodiment of the present disclosure.

[0387] This may be the MAC payload format of MsgB (fallback RAR). RAR 2300 may be, for example, a MAC PDU, and may include information 2310 on a timing advance (TA) to be applied by the UE and a temporary C-RNTI value 2320 to be used in subsequent operations.

[0388] *R field: It is a reserved bit and can be configured to, for example, "0".

[0389] * Timing Advance Command Field 2310: The Timing Advance Command field indicates an index value T used to control the amount of timing control that should be applied by the MAC entity. AThe size of the timing advance command field is, for example, 12 bits.

[0390] *UL Grant field: The UL Grant field indicates resources to be used in the uplink, where the size of the UL Grant field is, for example, 27 bits.

[0391] * Temporary C-RNTI field 2320: The Temporary C-RNTI field indicates a temporary identifier used by the MAC entity during random access, where the size of the Temporary C-RNTI field is, for example, 16 bits.

[0392] - Operation 5: The UE having received the RAR in operation 4 transmits message 3 (msg3) to the base station according to the scheduling information included in the RAR. The UE may include the unique ID value of the UE into msg3 to transmit msg3. The base station may attempt to receive msg3 according to the scheduling information that the base station has transmitted in operation 4.

[0393] - Operation 6: After receiving msg3 and identifying the ID information of the UE, the base station generates a message 4 (msg4) including the ID information of the UE and transmits the message 4 to the UE. The UE having transmitted msg3 in operation 5 may then attempt to receive msg4 to be transmitted in operation 6. The UE having received msg4 may compare the ID value included in msg4 with the ID value that the UE has transmitted in operation 5, and identify whether msg3 that the UE has transmitted is received by the base station. There may be a constraint on the time from the time when the UE has transmitted msg3 in operation 5 to the time when the UE receives msg4 in this operation, and the maximum time may be configured by the SIB in operation 2.

[0394] In the case where the initial access procedure using the above operation is applied to satellite communication, the propagation delay time in satellite communication may cause a problem. For example, the period (random access window) from when the UE sends a random access preamble (or PRACH preamble) in operation 3 to when the RAR is received in operation 4, that is, the maximum time to its reception, can be configured by ra-ResponseWindow, and the maximum time in the conventional LTE or 5G NR system can be configured to a maximum of 10ms.

[0395] Fig.24 is a schematic diagram showing an example relationship between a PRACH preamble configuration resource and an RAR reception time point in an LTE system according to an embodiment of the present disclosure.

[0396] Fig.25 is a schematic diagram showing an example relationship between a PRACH preamble configuration resource and an RAR reception time point in a 5G NR system according to an embodiment of the present disclosure.

[0397] refer to Fig.24 In the case of LTE, the random access window 2410 starts at a time point 3 ms after the transmission of the PRACH (random access preamble) 2400, and when the UE receives the RAR within the random access window (2420), it can be determined that the transmission of the PRACH preamble is successful.

[0398] refer to Fig.25 In the case of NR, the random access window 2510 starts from the control information region for RAR scheduling that first appears after the transmission of PRACH (random access preamble) 2500. In the case that the UE receives RAR within the random access window (2520), it can be determined that the transmission of the PRACH preamble is successful.

[0399] As an example, the TA used for uplink transmission timing in a 5G NR system can be determined as follows. First, determine T c =1 / (Δf max ·N f ), where Δf max =480·10 3 Hz and N f =4096. Furthermore, κ = T s / T c =64 and can be defined as T s =1 / (Δf ref ·N f,ref ),Δf ref =15·10 3 Hz,N f,ref =2048.

[0400] Fig.26 is a schematic diagram showing an example of downlink frame timing and uplink frame timing in a UE according to an embodiment of the present disclosure.

[0401] The UE can advance the uplink frame by T based on the timing of the downlink frame. TA =(N TA +N TA,offset )T c c, and perform uplink transmission. In the above, N TA The value of can be sent by RAR or can be determined based on MAC CE, and N TA,offset It may be a value configured in the UE or determined based on a predetermined value.

[0402] The RAR of the 5G NR system can indicate T A value, and in this case, T AIt can indicate one of 0, 1, 2, ..., 3846. In this case, when the subcarrier spacing (SCS) of RAR is 2 μ 15kHz, 2 μ Can be determined as N TA =T A ·16·64 / 2 μ After the UE completes the random access process, the base station may indicate a change in the TA value, which may be indicated by a MAC CE or the like. A The information may indicate one of 0, 1, 2, ..., 63, which may be used to calculate a new TA value by addition to or subtraction from an existing TA value, and the resulting TA value may be newly calculated as N TA_new =T A_old +(T A -31)·16·64 / 2 μ The indicated TA value may be applied by the UE for uplink transmission after a predetermined time.

[0403] Fig. 27 is a schematic diagram illustrating an example of continuous movement of a satellite relative to a UE located on the ground or the earth when the satellite revolves around the earth along a satellite orbit according to an embodiment of the present disclosure.

[0404] Since the distance between the UE and the satellite varies depending on the elevation angle at which the UE views the satellite, the propagation delays between the UE, the satellite, and the base station may be different.

[0405] Fig.28 is a schematic diagram showing an example structure of an artificial satellite according to an embodiment of the present disclosure.

[0406] The satellite may be composed of a solar panel or solar array 2800 for photovoltaic or solar power generation, a transmitting and receiving antenna (main mission antenna) 2810 for communicating with a UE, a transmitting and receiving antenna (feeder link antenna) 2820 for communicating with a ground station, a transmitting and receiving antenna (inter-satellite link) 2830 for communication between satellites, a processor for controlling transmission and reception and processing signals, etc. The satellite is of course not limited to the above examples, and an artificial satellite may include more than Fig.28 Moreover, according to an embodiment of the present disclosure, in the case where the satellite does not support communication between satellites, an antenna for transmitting and receiving signals between satellites may not be arranged. Fig.28 , it is shown that the L band of 1 GHz to 2 GHz is used for communication with the UE, but the K band (18 to 26.5 GHz), Ka band (26.5 to 40 GHz) and Ku band (12 to 18 GHz) corresponding to the high frequency band may also be used.

[0407] In addition, in various embodiments of the present disclosure, the term "base station (BS)" may refer to a predetermined component (or component set) configured to provide wireless access based on the type of wireless communication system, such as a transmission point (TP), a transmit-receive point (TRP), an enhanced Node B (eNodeB or eNB), a 5G base station (gNB), a macro cell, a femto cell, a Wi-Fi access point (AP), or other wireless-enabled devices. The base station may provide wireless access according to one or more radio protocols, for example, 5G 3GPP New Radio Interface / Access (NR), Long Term Evolution (LTE), Advanced LTE (LTE-A), High Speed ​​Packet Access (HSPA), Wi-Fi 802.11a / b / g / n / ac, etc.

[0408] In addition, in various embodiments of the present disclosure, the term "terminal" may refer to a predetermined component, such as "user equipment (UE)", "mobile station", "subscriber station", "remote terminal", "wireless terminal", "reception point" or "user device". For convenience, in various embodiments of the present disclosure, the term "UE" is used to refer to a device that accesses a base station, regardless of whether the device needs to be considered as a mobile device (such as a mobile phone or a smart phone) or a fixed device (such as a desktop computer or a vending machine).

[0409] Furthermore, in various embodiments of the present disclosure, the term “TA” may be used interchangeably with “TA information”, “TA value”, “TA index”, etc.

[0410] In various embodiments of the present disclosure, the data or control information sent by the base station to the UE may be referred to as a first signal, and the uplink signal associated with the first signal may be referred to as a second signal. For example, the first signal may include DCI, UL authorization, PDCCH, PDSCH, RAR, etc., and the second signal associated with the first signal may include PUCCH, PUSCH, msg3, etc.

[0411] In addition, there may be an association between the first signal and the second signal. As an example, in the case where the first signal is a PDCCH including an UL grant for uplink data scheduling, the second signal corresponding to the first signal may be a PUSCH including uplink data. At the same time, the difference (gap) between the time points of sending and receiving the first signal and the second signal may be a predetermined value between the UE and the base station. Alternatively, the difference between the time points of sending and receiving the first signal and the second signal may be determined by an indication of the base station, or by a value sent through higher layer signaling.

[0412] Since the distance between the UE and the satellite and the distance between the satellite and the base station are long, and the satellite moves continuously, when the UE or the base station receives a signal sent by the base station or the UE, a time offset may be generated due to a delay time in the UE-satellite direct communication. Therefore, the present disclosure provides a method and an apparatus, wherein in order to correct the time offset, the base station indicates time offset information, and the UE corrects the time offset according to the time offset information.

[0413] The following embodiments are described based on the assumption of communication between a UE, a satellite and a ground station, but do not exclude the case where a satellite base station communicates with the UE.

[0414] In this disclosure, time offset may be used interchangeably with timing advance.

[0415] The methods and devices provided by various embodiments of the present disclosure can be applied not only to satellite communication systems, but also to ground communication systems. Moreover, the following embodiments can be operated in combination with each other.

[0416] [First embodiment]

[0417] A first embodiment of the present disclosure provides a method and apparatus in which a UE directly determines (eg, calculates) a TA value in a case where the UE transmits an uplink signal to a satellite or a base station, and applies the determined TA value.

[0418] Further, the first embodiment of the present disclosure describes a method and apparatus, wherein a base station or a satellite indicates a TA value to be applied to the UE when the UE transmits an uplink signal to the satellite or the base station, and the UE applies the indicated TA value to transmit the uplink signal.

[0419] In addition, the first exemplary embodiment of the present disclosure describes a method and apparatus in which the UE adaptively determines a TA value to be applied when the UE transmits an uplink signal to a satellite or a base station. More specifically, the first exemplary embodiment of the present disclosure describes a method in which the UE determines a TA value on its own, and a method and apparatus in which a base station or a satellite as described in the present disclosure indicates a TA value to the UE, and the UE adaptively selects one of the methods of applying the indicated TA value and determines the TA value.

[0420] First, the UE may compare the uplink transmission time point for uplink synchronization with the downlink reception time point, and advance the uplink transmission time point by T from the downlink reception time point based on the comparison result. TA For satellite communications, the TA calculated T TA It can be expressed as shown in the following equation 5.

[0421] [Equation 5]

[0422] TTA =(N TA +N TA,UE-specific +N TA,common +N TA,offset )×T c

[0423] In Equation 5, T c It can be T C =1 / (Δf max ·N f ), and Δf max =480·10 3 Hz and N f =4096. In equation 5, N TA It can be based on the T included in the RAR or MAC CE received from the base station. A The value is determined by the value of TA,offset It can be a pre-fixed or pre-arranged value. In equation 5, N TA,UE-specific It can be a TA correction value measured by the UE based on the position of the UE and the satellite (or reference position), and N TA,common It may be a TA correction value configured or indicated by the base station using higher layer signaling or a physical layer signal.

[0424] Compared with the following equation 6 as a conventional TA application method, equation 5 may be a method in which the parameter N is added. TA,UE-specific and N TA,common The equation.

[0425] [Equation 6]

[0426] T TA =(N TA +N TA,offset )×T c

[0427] Fig.29 FIG. 1 is a diagram showing a UE according to an embodiment of the present disclosure determining N from initial access TA Schematic diagram of an example process.

[0428] Fig.30 FIG. 1 is a diagram showing a UE according to an embodiment of the present disclosure determining N from initial access TA 、N TA,UE-specific and N TA,common Schematic diagram of an example process.

[0429] refer to Fig.29 UE applies N TA = 0 sends a PRACH preamble code to the base station (2901), and the base station sends an indication N to the UE TA Then, the UE applies N TA=A to send PUSCH (2905), and the base station sends an indication ΔN to the UE TA MAC CE (2907). Afterwards, the UE can TA =A+ΔN TA To send PUSCH (2909).

[0430] refer to Fig.30 , the base station sends satellite information and N to the UE TA,common and drift rate configuration information (3001). Then, the UE assumes that N TA = 0, and applies the N measured by itself TA,UE-specific and the configured N TA,common , to send a PRACH preamble code to the base station (3003). Afterwards, the base station sends an indication N to the UE. TA RAR(3005), and N TA,UE-specific and N TA,common can be updated (3007). Afterwards, the UE can TA To send PUSCH (3009), T TA It is assumed that N TA =A calculated according to equation 5, and the base station may send an indication ΔN to the UE TA MAC CE (3011). Afterwards, N TA,UE-specific and N TA,common (3013), and the UE can TA To send PUSCH (3015), the T TA By applying N TA =A+ΔN TA and the updated N TA,UE-specific and N TA,common is calculated according to Equation 5.

[0431] T TA Can be based on T A = 0, 1, 2, ..., 3846 is determined as N TA =T A 16·64 / 2 μ , where T A Sent on RAR or msgB. Also, T A = 0, 1, 2, ..., 63 can be sent through MAC CE and can be updated to N TA_new =N TA_old +(T A -31)·16·64 / 2 μ Furthermore, Δf max ·N f , T sent via RAR or msgBA , T sent by MAC CE A The value may vary according to the communication system. TA_new =T A_old +(T A -M)·16·64 / 2 μ In the case of A , if T A The maximum value of is greater than 63, then the value of M can be a value greater than or equal to 31, and if T A If the maximum value of is less than 63, the M value may be a value equal to or less than 31, and the UE may determine the updated N based on this. TA Value N TA_new .

[0432] Fig.31 is a schematic diagram schematically illustrating another example of an operation process of a UE in a communication system according to an embodiment of the present disclosure.

[0433] UE can refer to Fig.31 The described process is used to perform the initial access procedure, and the TA is determined after performing the initial access procedure, which will be described in detail below.

[0434] First, in operation 3111, the UE may detect a synchronization signal and a PBCH block (SSB) received from a base station.

[0435] In operation 3113, the UE may decode a system information block (SIB) based on the detected SSB. The UE may detect information about random access channel (RACH) resources by decoding the SIB.

[0436] In operation 3115, the UE may obtain (or decode) satellite information by decoding the SIB. According to an embodiment of the present disclosure, the satellite information may include at least one of various parameters, such as location information of the satellite. In operation 3115, the UE may obtain a UE-specific TA correction value, for example, N based on the location (or reference location) of the UE and the satellite and based on the obtained location information. TA,UE-specific .

[0437] In operation 3117, the UE may obtain (or decode) a common TA offset, such as N by decoding the SIB. TA,common .

[0438] In operation 3119, the UE may TA,UE-specific and N TA,common The TA is calculated and the PRACH is sent to the base station by applying the calculated TA.

[0439] In operation 3121, the UE may receive a RAR including a TA value in response to transmission of the PRACH.

[0440] In operation 3123, the UE may control the TA based on the received RAR.

[0441] In operation 3125, the UE may transmit msg3 to the base station by applying TA. msg3 is part of the random access procedure and may refer to a message including a C-RNTI MAC CE or a common control channel (CCCH) SDU and transmitted in an uplink shared channel (UL-SCH), and msg3 may be the first scheduled transmission of the random access procedure.

[0442] In operation 3127, the UE may receive a MAC CE including a TA control value from the base station.

[0443] In operation 3129, the UE may apply the TA based on the TA control value included in the MAC CE, and transmit the PUSCH and / or PUCCH.

[0444] As reference Fig.31 The operation process of the described UE, that is, the process of performing the initial access process and determining the TA after performing the initial access process, can be compared with the operation process of the UE according to another embodiment of the present disclosure, as shown in Table 24 below.

[0445] [Table 24]

[0446]

[0447]

[0448] Furthermore, the reference Fig.31 The order of some operations in the described operation procedure of the UE, and for example, the order of the operation of decoding the satellite information and the operation of decoding the common TA offset may be changed.

[0449] Although referenced Fig.31 The operation process of the UE in the communication system according to various embodiments of the present disclosure is described, but it should be noted that Fig.31 Various modifications can be made. For example, Fig.31 The steps are shown in the following sections, but Fig.31 The operations described in the description may overlap with each other or be performed in parallel, their order may be changed, or one or more operations may be performed multiple times apparently.

[0450] Fig.32 is a schematic diagram schematically illustrating another example of an operation process of a UE in a communication system according to an embodiment of the present disclosure.

[0451] UE can refer to Fig.32 The described process performs the initial access process, and determines the TA after performing the initial access process, which will be described in detail below. Specifically, Fig.32 The operation flow of the UE shown in may be an operation flow of the UE based on a random access procedure for a 2-step RA type, and Fig.31 An operation flow of a UE based on a random access procedure for a 4-step random access (RA) type is shown.

[0452] First, in operation 3211, the UE detects the SSB received from the base station. In operation 3213, the UE decodes the SIB based on the detected SSB. Here, the UE can obtain information about RACH resources by decoding the SIB.

[0453] In operation 3215, the UE may obtain (or decode) satellite information by decoding the SIB. According to an embodiment of the present disclosure, the satellite information may include at least one of various parameters, such as location information of the satellite. In operation 3215, the UE may obtain a UE-specific TA correction value, for example, N based on the location (or reference location) of the UE and the satellite and based on the decoded satellite information. TA,UE-specific .

[0454] In operation 3217, the UE may obtain (or decode) a common TA offset, such as N by decoding the SIB. TA,common .

[0455] In operation 3219, the UE may TA,UE-specific and N TA,common TA is calculated, and msgA is sent to the base station by applying the calculated TA. According to an embodiment of the present disclosure, msgA may be transmission of a preamble and a payload in a random access procedure of a 2-step random access (RA) type.

[0456] In operation 3221, the UE may receive msgB including a TA value from the base station. According to an embodiment of the present disclosure, msgB is a response to msgA in a random access procedure for a 2-step RA type and may include (multiple) responses to contention resolution, (multiple) backoff indications, and backoff indications.

[0457] In operation 3223, the UE may control the TA based on the TA control value included in msgB.

[0458] In operation 3225, the UE may transmit a PUSCH and / or a PUCCH by applying the controlled TA.

[0459] As reference Fig.32The operation process of the described UE, that is, the process of performing the initial access process and determining the TA after performing the initial access process, can be compared with the operation process of the UE according to another embodiment of the present disclosure, as shown in Table 25 below.

[0460] [Table 25]

[0461]

[0462] Furthermore, the reference Fig.32 The order of some operations in the described operation procedure of the UE, and for example, the order of the operation of decoding the satellite information and the operation of decoding the common TA offset may be changed.

[0463] At the same time, although reference has been made Fig.32 The operation process of the UE in the communication system according to various embodiments of the present disclosure is described, but it should be noted that Fig.32 Various modifications can be made. For example, Fig.32 shows continuous operation, but Fig.32 The operations may overlap with each other or be performed in parallel, their order may be changed, or one or more operations may be performed multiple times.

[0464] Meanwhile, N used in the embodiments of the present disclosure TA,UE-specific is a value calculated and applied by the UE. Therefore, the base station may not know N calculated by the UE. TA,UE-specific Further, N calculated by the UE TA,UE-specific The value of may change over time due to the movement of the UE or the satellite.

[0465] Therefore, in embodiments of the present disclosure, the base station may need to consider N which may change over time. TA,UE-specific The value of N is used to control the TA of the UE, and therefore the UE may need to configure the update N TA,UE-specific Therefore, the UE may update N based on one of the following methods (eg, method 1-1 to method 1-6 or a method combining at least two of method 1-1 to method 1-6). TA,UE-specific The value of .

[0466] -Method 1-1: The UE always updates N at each time point when receiving a SIB including satellite information (e.g., including satellite information, etc.) TA,UE-specific Method 1-1 may be applied to a case where the UE determines that a SIB is received from a base station or a case where a paging signal indicating an update of the SIB is received from a base station.

[0467] -Method 1-2: The base station may indicate the TA alone (for example, N TA,UE-specific) and configures a period and an offset for recalculating the TA value (e.g., updating the TA value) according to the change rate of the TA. In this case, the UE can update the TA (e.g., N ) at a time point determined according to the period and the offset. TA,UE-specific ), and the amount of TA updated by the UE can be determined according to the change rate of TA. In various embodiments of the present disclosure, the base station can indicate the change rate of TA based on an explicit method or an implicit method.

[0468] -Method 1-3: The base station can be configured to update the N by the UE based on the location of the satellite and the location of the UE TA,UE-specific In this case, the UE may update the TA at a corresponding time point determined according to the update period and offset configured by the base station. In various embodiments of the present disclosure, the base station may indicate the update period and offset based on an explicit method or an implicit method.

[0469] - Method 1-4: In each of at least some cases of performing uplink transmission (e.g., PUCCH / PUSCH, PRACH, and SRS transmission), the UE may always update and apply N at a corresponding time point (e.g., at a corresponding time slot time point) TA,UE-specific (Both are possible in each execution case, depending on regular cycles and at irregular execution times).

[0470] -Method 1-5: The UE updates N based on the time point at which the TA command sent by the base station through the MAC CE expires TA,UE-specific For example, the UE updates N at the time when the TA expires. TA,UE-specific . Based on the timer for the TA command, the expiration of the TA command may refer to the timer value reaching a specific time point. The timer for the TA command may be configured as timeAlignmentTimer and may be a parameter indicating how long the uplink time synchronization takes. When a new TA command is received, the UE may start or restart the timeAlignmentTimer. When the timeAlignmentTimer expires, the UE may clear the HARQ buffer and perform RRC configuration anew, etc.

[0471] -Method 1-6: has been introduced with N TA,UE-specific The relevant new timer timeAlignmentTimer_UEspecific, and the UE can update N based on the new timer timeAlignmentTimer_UEspecific TA,UE-specific . UE newly calculates N TA,UE-specific Or about N TA,UE-specificWhen the information of N is sent to the base station, timeAlignmentTimer_UEspecific can be started or restarted. When timeAlignmentTimer_UEspecific expires, the UE can calculate N again. TA,UE-specific To update it, N TA,UE-specific Configured to 0, or perform PRACH transmission.

[0472] [Second embodiment]

[0473] The second embodiment provides a method and apparatus for transmitting (reporting) a timing advance (TA) value being applied or already applied by a UE to a base station or a satellite. In the present disclosure, a satellite may include an object located above the ground, and corresponds to concepts including aircraft, airships, and the like.

[0474] The UE may perform an operation of transmitting the TA value being applied by the UE to the base station. This is to notify the base station of the applied TA value in the case where the UE applies the TA value without any separate instruction from the base station, or to identify or determine how the UE applies the TA value indicated by the base station. For example, an operation may be performed to identify the TA value of the UE by the satellite newly connected to the UE in the case where the satellite connected to the UE changes. As an example, the UE may apply a TA calculated based on the position of the UE and the satellite itself.

[0475] The UE may report the TA value to the base station using one of the following methods or a combination of at least two of the following methods.

[0476] -Method 2-1: The base station may trigger the TA value report of the UE through DCI. The base station may trigger the TA value report through some bit field values ​​of the DCI or a combination of bit field values. In the case where a field indicating the triggering of the TA value report is included in the DCI and a field of the received DCI is configured as a specific value, the UE may understand that the TA value report is triggered. Alternatively, in the case where the value of one or more fields (for example, for other purposes) included in the DCI is configured as a predetermined value, the UE may understand that the TA value report is triggered. The UE may send the TA value to the base station at a specific time point based on the time point when the DCI is received.

[0477] -Method 2-2: The base station may trigger the TA value report of the UE through the MAC CE. The base station may trigger the TA value report by using some bit values ​​or bit field values ​​of the MAC CE, and the UE may send the TA value to the base station at the time point of receiving the MAC CE or at a predetermined time point after the time point of receiving the MAC CE.

[0478] -Method 2-3: The base station may indicate which TA value the UE should report through RRC configuration. For example, the base station may configure the period and offset value of the TA report through higher layer signaling or / and a specific condition for the UE to report the TA value, and determine the time point at which the UE reports the TA value, in which case a TA value application time as a reference may be specified (i.e., the time at which the TA value to be reported is applied, which may be referred to as a TA value reference time point). The specific condition for the UE to report the TA value may be, for example, a case where the TA value is greater than or equal to a predetermined value, or a case where the distance between the UE and the satellite is longer than or equal to a predetermined value, and the predetermined value may be information or a fixed value configured through higher layer signaling or sent through SIB, etc.

[0479] -Method 2-4: The UE may report the TA value without a separate trigger from the base station. For example, method 4 may correspond to sending information indicating the TA value according to a specific condition from the UE to the base station, and the specific condition (without signaling such as DCI, MAC CE, or RRC for triggering from the base station) is a condition for the time to perform TA value reporting or a comparison result of the TA value applied by the UE with a specific threshold, etc., and may be predetermined.

[0480] According to an embodiment of the present disclosure, in the case of sending a TA value, the UE may send the TA value through a physical channel such as PUCCH or PUSCH, or may transmit the TA value information to the base station through a higher layer signaling. In the case of the UE transmitting the TA value information through a physical channel, resources for reporting the TA value information may be configured through higher layer signaling.

[0481] According to an embodiment of the present disclosure, the TA value report may refer to reporting the T in the above equation. TA The value or N TA,UE-specific Alternatively, the base station may configure the UE to report T via SIB or higher layer signaling. TA and N TA,UE-specific Which one of them.

[0482] Determining the reference time point for reporting the TA value by the UE and the time point for reporting the TA value may be determined based on the time point at which the UE performs the TA value report, the time point at which the TA value report is triggered, etc. For example, in the case where the TA value report is triggered in time slot n by DCI, the UE may report the TA value applied or calculated in time slot nK, or may report the TA value to the base station in time slot n+N. K and N may be values ​​determined according to the subcarrier spacing or UE capability, DL / UL configuration of the time slot, PUCCH resource configuration, etc., respectively.

[0483] According to an embodiment of the present disclosure, K may be 0. K=0 may mean that the UE reports the TA value based on the time point at which the TA value report trigger signal is received. Further, K may be less than 0, and in this case, for example, the report information may be generated and reported by precalculating the TA value at the time point at which the UE reports the TA value. In addition, K may be an integer greater than 0. This may mean that the UE reports the TA value at a time point earlier than the time point at which the UE reports the TA value (e.g., time slot n+N), which may be considered as reporting the TA value at an earlier time point because time is required to encode the information to be reported by the UE and prepare for transmission.

[0484] Fig.33 and Fig.34 1 is a schematic diagram showing example operations of a base station and a UE for TA value reporting of a UE according to an embodiment of the present disclosure. When reporting a TA value according to the present disclosure, the TA value applied by the UE may be indicated in units of milliseconds, time slots, or symbols, or may be provided as information including a value after a decimal point instead of an integer. The TA value report according to the present disclosure may include an absolute value of the TA, and may include a TA value previously indicated by the base station, a relative TA value other than a predetermined TA value, a change in the TA value (e.g., a TA change within a predetermined time), and the like.

[0485] Fig.33 is a schematic diagram illustrating the operation of a base station.

[0486] The base station may send configuration information related to TA reporting through higher layer signaling (operation 3300). The configuration information related to TA reporting may include at least one of the following: for example, information for configuring TA reporting, such as a period and offset for performing TA reporting, a TA reporting trigger condition, TA value reference time point information, a type of TA information to be reported, resource configuration information for performing TA reporting, etc.

[0487] The base station may trigger a TA report to the UE (operation 3310). The triggering may be performed by, for example, higher layer signaling or DCI as the above-mentioned specific content, or may be omitted.

[0488] The base station may receive a TA report transmitted by the UE according to the transmitted configuration information (operation 3320).

[0489] Fig.34 is a schematic diagram illustrating the operation of a UE.

[0490] The UE may receive configuration information related to the TA report sent by the base station through higher layer signaling (operation 3400). The configuration information may include at least one of the following: for example, information for configuring the TA report, such as a period and offset for performing the TA report, a TA report triggering condition, TA value reference time point information, a type of TA information to be reported, resource configuration information for performing the TA report, etc.

[0491] The UE may receive a signal for triggering a TA report transmitted by the base station (operation 3410). The trigger may be performed by, for example, higher layer signaling or DCI as the above-mentioned specific content, or may be omitted.

[0492] The UE sends a TA report according to the received configuration information (3420). For example, in the case of receiving TA report resource information, the UE sends a TA report in the configured resources.

[0493] Fig.33 and Fig.34 The order of the various operations disclosed in the description may be changed and applied, or other operations may be added or omitted.

[0494] [Third embodiment]

[0495] The third embodiment provides a method for a UE to calculate, determine, and report the N described in the first and second embodiments. TA,UE-specific N can be calculated based on the distance between the UE and the non-terrestrial network (NTN) satellite. TA,UE-specific The UE may calculate its own position by receiving a signal from a navigation satellite in a satellite navigation system, and the navigation satellite may be different from the NTN satellite. Of course, the UE is not limited to the above method when calculating its own position, and the UE's position may also be sent from another entity.

[0496] According to an embodiment of the present disclosure, the UE can estimate the delay time between the satellite and the UE based on the position of the UE and the position of the satellite, and correct the estimated delay time value by itself to perform uplink transmission. For example, the satellite can send information about the position of the satellite through broadcast information, and the UE can receive information about the position of the satellite sent by the satellite and compare the information about the position with the position of the UE itself. The position of the UE can be known using one of various types of global positioning systems (GPS) or using information from a base station independently or a combination thereof. The UE can calculate the uplink transmission time by estimating the time required for the radio wave to be transmitted to the satellite by comparison.

[0497] For example, when the UE receives a signal in time slot n via a downlink at a specific time point and needs to perform uplink transmission corresponding to the signal in time slot n+k, the uplink transmission can be sent 2×Td earlier than the time point of time slot n+k.

[0498] According to an embodiment of the present disclosure, the delay time Td may be a delay time from the UE to the satellite calculated based on the position information of the satellite and the UE, or may be a value corresponding to the delay time. The delay time Td may be a value obtained by dividing the distance between the UE and the satellite or a value corresponding to the distance by the speed of light or a value corresponding to the speed of light. For example, the position of the satellite may be a value calculated based on the time slot n+k in which the UE performs uplink transmission. This is because the position of the satellite in time slot n and the position of the satellite in time slot n+k may be different depending on the movement of the satellite.

[0499] Considering the maximum distance of about 100km to the base station, a propagation delay time equal to or less than 1ms can be generated in the terrestrial network, but in the satellite network, the distance to the satellite can be thousands of km, and the distance between the satellite and the base station can also be thousands of km, and therefore the delay time in the satellite network can be significantly longer than the delay time in the terrestrial network.

[0500] Fig.35 is a schematic diagram illustrating an example of a difference in propagation delay between a terrestrial network and a satellite network according to an embodiment of the present disclosure.

[0501] In satellite network communications, the delay time can vary depending on the altitude and elevation angle of the satellite, and Fig.35 The distance between the UE and the satellite and the propagation round trip time according to the elevation angle are shown when the altitude of the satellite is 700km. In the case of a satellite network, assuming a low earth orbit satellite, and in the case where the elevation angle is within 0 to 180 degrees, the radio round trip time (radio RTT) (which may include the round trip time spent for transmitting signals between transceivers and the processing time in the corresponding node) can be from 40.9ms to 9.3ms. According to an embodiment of the present disclosure, the delay time is only an example and may vary depending on the altitude and orbit of the satellite, and for example, in the case of a higher altitude, the delay time may be further increased on average.

[0502] In the terrestrial network, since the maximum delay time is within 1 or 2 ms, the time slot timing for the base station to perform downlink transmission and the time slot timing for the base station to perform uplink reception can be matched by the timing advance provided in the LTE and 5G NR systems (that is, the indices of the DL time slot and the UL time slot can match each other). That is, when the UE advances the uplink transmission from the downlink time point by the value of the timing advance indicated by the base station, the time point at which the base station receives the uplink signal sent by the UE can become the same as the downlink time point of the base station. On the other hand, in the satellite network, the time slot timing for the base station to perform downlink transmission and the time slot timing for the base station to perform uplink reception cannot be matched by the timing advance provided in the existing LTE and 5G NR systems. This is because the propagation delay time generated in the satellite network is as large as tens of milliseconds, and is therefore greater than the maximum value of the timing advance provided in the conventional LTE and 5G NR systems.

[0503] The satellite navigation system may also be referred to as a global navigation satellite system (GNSS), and the GNSS may include, for example, the GPS of the United States, the GLONASS of Russia, the Galileo of the European Union, the BeiDou of China, etc., but is certainly not limited to the above examples. The GNSS may include a regional navigation satellite system (RNSS), and the RNSS may include, for example, the IRNSS of India, the QZSS of Japan, the KPS of South Korea, etc. Meanwhile, the signal transmitted in the GNSS may include at least one of supplementary navigation information, a normal operating state of a satellite, a satellite time, a satellite orbit power, a satellite altitude, a reference time, and information about various compensation files.

[0504] Meanwhile, in various exemplary embodiments of the present disclosure, the NTN satellite may be a communication satellite for transmitting a signal for connection between a UE and a base station. In addition, in various exemplary embodiments of the present disclosure, the GNSS satellite may be a signal transmitting satellite of a satellite navigation system.

[0505] At the same time, the UE may receive a signal from each of one or more GNSS satellites, calculate the position of the UE itself based on the signal received from each of the one or more GNSS satellites, and identify the reference time in each of the one or more GNSS satellites. In the case where the UE can calculate multiple positions of the UE based on signals received from multiple GNSS satellites, the UE may calculate the true position of the UE based on an average of multiple positions, a position corresponding to a received signal with the highest strength among multiple positions, an average of multiple positions based on signal strength (e.g., a method for applying a weighted value in a position corresponding to a signal with the highest signal strength), etc. Here, the scheme in which the UE calculates the position of the UE based on signals received from multiple GNSS satellites may be implemented in various forms, and its detailed description is omitted.

[0506] In various embodiments of the present disclosure, the time obtained from the GNSS or the time of the base station transmitted by the base station may be based on, for example, Coordinated Universal Time (UTC), which is based on the time starting at 00:00:00 on January 1, 1900 in the Gregorian calendar. This may vary depending on the type of GNSS system, and a reference time as shown in Table 26 below may be used.

[0507] [Table 26]

[0508]

[0509] In Table 26 above, NavIC may refer to navigation with Indian constellation, QZS may refer to Quasi Zenith satellite, QZSS may refer to Quasi Zenith Satellite System, QZST may refer to Quasi Zenith System Time, SBAS may refer to Space Based Augmentation System, and BDS may refer to BeiDou Navigation Satellite System.

[0510] In addition, the base station can indicate the type of GNSS system used as a reference for position or time information used by the base station itself through a satellite, and for example, the indication shown in the following Table 27 can be used.

[0511] [Table 27]

[0512] Value of gnss-TO-ID instruct 1 GPS 2 Galieo 3 QZS 4 GLONASS 5 BDS 6 NavIC 7-15 reserve

[0513] As described above, the UE may calculate the time taken when a signal is transmitted from the NTN satellite to the UE based on the position of the UE calculated by the UE and the position of the NTN satellite received from the NTN satellite, and determine the TA value based on the time. In the case where the UE determines the TA value, the UE may also consider the distance from the NTN satellite to another NTN satellite in the case where the distance from the NTN satellite to a base station on the ground or the corresponding signal is transmitted to the ground base station via another NTN satellite.

[0514] Different from this, the UE can obtain reference time information from information sent by the GNSS satellite, compare the time information sent by the NTN satellite with the reference time information obtained from the GNSS satellite, and calculate the time required from the NTN satellite to the UE (propagation delay) based on the comparison result.

[0515] The location and time information of NTN satellites can be sent by the base station to the UE via SIB. This can be sent directly by the NTN satellite.

[0516] Assume that the distance between the UE and the satellite or the value corresponding to the distance is d UE,sat(in km) and the speed of light is v c (unit: km / s), N TA,UE-specific Can be based on d UE,sat / v c (in seconds). For example, it can be determined and applied as It is used to The value of N is set to an integer to determine TA,UE-specific Alternatively / additionally, the UE may determine N by a method such as a combination of at least one of the following three methods: TA,UE-specific , and report N to the base station TA,UE-specific information.

[0517] -Method 3-1: UE can determine N TA,UE-specific =(D+a) / T C D is an integer, and a is a decimal greater than or equal to 0 and less than 1. Here, and Method 3-1 may be a method for dividing the propagation delay between the UE and the satellite into an integer part and a decimal part, and reporting only the integer or a value corresponding thereto, or separately reporting the integer and the decimal or value corresponding thereto. By using this method, the number of bits required for reporting the propagation delay can be reduced. Although it has been described above that the decimal part becomes T c The integer multiple of , but the fractional part can be determined as 16·64·T c / 2 μ In the above, μ may refer to the current carrier, BWP or subcarrier spacing of the relevant CORESET. Alternatively, μ may be a value used for a transmit / receive signal such as a PDSCH or PUSCH to be transmitted / received. Here, μ=0, 1, 2, 3, 4, 5 may be values ​​corresponding to subcarrier spacings of 15kHz, 30kHz, 60kHz, 120kHz, 240kHz and 480kHz, respectively. Alternatively, μ may be configured by the base station to determine N through higher layer signaling. TA,UE-specific Alternatively, a fixed value may be used for μ, and for example, one of 0, 1, 2, 3, 4, 5 may be fixedly used as μ=5.

[0518] -Method 3-2: The UE can determine such that N TAUE-specific It is 16.64 / 2 μ It can be determined that

[0519] In this disclosure, It may refer to the largest integer not greater than x, and the number may be rounded down in integer units, that is, the decimal value is discarded. Of course, it is not limited to the above examples, and in the present disclosure, rounding up or rounding from a decimal point may be used instead of using Round down. That is, in the present disclosure, a floor function, a ceiling function, or a rounding function may be interchangeable with each other. In the above, μ may refer to the current carrier, BWP, SIB, or subcarrier spacing of the relevant CORESET. Alternatively, μ may be a value for a transmit / receive signal such as a PDSCH or PUSCH to be transmitted / received. Here, μ=0, 1, 2, 3, 4, 5 may be values ​​corresponding to subcarrier spacings of 15kHz, 30kHz, 60kHz, 120kHz, 240kHz, and 480kHz, respectively. Alternatively, μ may be configured by the base station to determine N through higher layer signaling. TA,UE-specific Alternatively, a fixed value may be used for μ, and for example, μ=5 may be fixedly used. Alternatively, for calculating N TA,UE-specific The μ can be individually configured by the base station through SIB or higher layer signaling.

[0520] -Method 3-3: N can be determined TA,UE-specific =N A,UE-specific ·16·64 / 2 μ , in the above equation, N A,UE-specific can be determined to make N A,UE-specific Closest to d UE,sat / (v c ·T c ). Alternatively, it can be determined such that The smallest integer value or such that The maximum integer value of .

[0521] Method 3-4: UE can determine N according to base station configuration TA,UE-specific = 0. This may be because UEs within coverage in a particular beam of a satellite have small differences in the propagation delay incurred in the link between the UE and the satellite (which may be referred to as the serving link), and thus uplink time synchronization may be provided by the conventional TA mechanism and N TA,common The base station can configure the UE through SIB to set N TA,UE-specific The value is configured as N TA,UE-specific = 0, or the UE uses N calculated based on the positions of the satellite and the UE and the speed of light of the GNSS signal TA,UE-specific As another example, the base station may configure the UE through SIB or separate RRC signaling to continuously use N calculated based on the time point of sending the PRACH preamble according to the positions of the satellite and the UE and the speed of light of the GNSS signal.TA,UE-specific Until there is a separate instruction or configuration, or use the newly calculated N at each uplink transmission time point TA,UE-specific That is, N can be determined as described below by the above equation 5 TAUE-specific The value of .

[0522]

[0523] Methods 3-1 to 3-4 are only used to determine N based on the distance between the UE and the satellite (or a value corresponding thereto) and the speed of light. TA,UE-specific , and there may be more different methods. For example, typically, when N TAUE-specific If the value is defined as an integer or an expression based on an integer, The above method may be generally expressed as indicating the value of K as a multiple of a specific integer or rational number. Here, K may be a predetermined value or a value determined by a signaling parameter. Method 2 refers to K=16·64 / 2 μ The situation, and K can be based on the system parameters μ and T c This scheme has the advantage of expressing more different values ​​through the same bit signaling, rather than having N TA,UE-specific In addition, in each method, the value of can be rounded up to the nearest integer. Or round the Round(x) operation to determine the value, rather than using a Round down.

[0524] [Fourth embodiment]

[0525] The fourth exemplary embodiment provides a method, by which a base station transmits the N described in the first and second embodiments to a UE. TA,common , and the UE performs calculations and applications.

[0526] In the following, these methods are that the base station transmits N to the UE using configuration and indication. TA,common information, and one or more of these methods may be combined and applied.

[0527] -Method 4-1: The base station can configure an offset value in the UE through RRC signaling. The value configured through RRC signaling is N A,common And N can be determined based on this value TA,common .

[0528] -Method 4-2: The base station can indicate an offset value to the UE via MAC CE. The value configured via MAC CE is T A,common , and N can be determined based on this value TA,commonCompared with method 4-1, the advantage of this method is that the base station and the UE can define the base station and the UE application N TA,common As an example, N TA,common It may be applied after a predetermined time based on a time point at which a MAC CE is received or a time point at which an ACK is sent in response to receiving a MAC CE. For example, the base station may transmit N in milliseconds through an 8-bit MAC CE. A,common , and indicates 0ms to 255ms. Here, N TA,common Determined as N TA,common =T A,common / (1000·T c )

[0529] -Method 4-3: The base station may configure one or more offset values ​​in the UE through higher layer signaling. Alternatively, these values ​​may be pre-configured. The configured values ​​may become T A,common candidate values, and the base station can indicate one of the candidate values ​​through MAC CE.

[0530] -Method 4-4: The base station can configure an offset value in the UE through SIB. The value configured through SIB is T A,common , and N can be determined based on this value TA,common UE uses N when sending PRACH preamble during initial access TA,common The TA is calculated and applied based on the value of ΔT. Afterwards, ΔT can be indicated to the UE via MAC CE. A,common , and the UE can use it to calculate N TA,common The change in TA,common(new) =N TA,common(old) +(ΔT A,common -X)·y. In the above, x and y can be calculated based on the number of bits and the number of bits used for ΔN A,common For example, N can be determined TA,common(new) =N TA,common(old) +(ΔT A,common -M)·16·64 / 2 μ Here, the value of M can be 31, or in the ΔT that can be indicated by the MAC CE. A,common The maximum value of is greater than 63 and may be greater than or equal to 31, and in ΔT A,common When the maximum value is less than 63, it can be a value equal to or less than 31.

[0531] -Method 4-5: The base station can indicate an offset value to the UE via MAC CE. The configured value is T A,common , and N TA,commonCompared with method 4-1, the advantage of this method is that it can define the base station and UE application N TA,common As an example, N TA,common It can be applied after a predetermined time based on the time point of receiving the MAC CE or the time point of sending the ACK in response to receiving the MAC CE. For example, the base station can send the 16·64·T through a MAC CE of about 19 bits or 24 bits. c / 2 μ T A,common In this case, N TA,common Determined as N TA,common =T A,common 16·64 / 2 μ The number of bits of the MAC CE is just an example, and another value may be applied.

[0532] -Method 4-6: The base station can indicate an offset value to the UE via MAC CE. The configured value is T A,common , and accordingly, N TA,common It can be determined based on the altitude of the satellite. Compared with methods 4-5, the advantage of this method is that the number of bits to be transmitted can be reduced. For example, the base station can transmit a MAC CE with 16·64·T through approximately 16 bits. c / 2 μ T in seconds A,common In this case, N TA,common Determined to be On top, h sat is the height of the satellite. This may mean that, in the case where the satellite is at a certain height, the minimum distance between the UE and the satellite is the certain height, and therefore the base station only needs to pass T A,common The remaining additional distance is signaled. The number of bits of the MAC CE is just an example and another value may be applied.

[0533] In the above equation, it is possible to convert The value of is defined as an integer or a rational number. For example, in the third embodiment, it can be based on h sat The value instead of d UE,sat The value of and use of or Obviously, integer or rational number schemes similar to those described above can be applied to For example, you can define Moreover, this situation is similar to Consider K = 16·64 / 2 μThe same scheme is used for the case of . Further, for the operations for integer or rational number schemes, various other operations such as ceiling and floor and rounding down can be applied.

[0534] -Method 4-7: The base station can transmit N at the time of reception through SIB TA,common The value of and about N TA,common N can be transmitted to a specific UE through RRC signaling instead of SIB. TA,common The value of and about N TA,common The information of the change rate of the RRC_RS may be transmitted, and the transmission method may vary depending on the state of the UE (RRC_idle, RRC_inactive, RRC_connected).

[0535] The SIB can transmit information about N through one, two or three parameters. TA,common As an example, assume that information about the rate of change is transmitted through a parameter A and N is transmitted through SIB. TA,common The time point of performing uplink transmission is t1, and the time point of performing uplink transmission is t2, N TA,common(t2) , which is the N that the UE needs to apply at t2 TA,common can be calculated as N TA,common(t2) =N TA,common(t1) +(t2-t1)·A. Here, the units of t1 and t2 may be milliseconds, and the unit of A may be Tc / milliseconds. That is, A may indicate N TA,common As another example, assume that information about the rate of change is transmitted through two parameters A and B, and N is transmitted through SIB. TA,common The time point of performing uplink transmission is t1, and the time point of performing uplink transmission is t2, N TA,common(t2) , which is the N that the UE needs to apply at t2 TA,common can be calculated as N TA,common(t2) =N TA,common(t1) +(t2-t1) 2 ·B+(t2-t1)·A. (In the case where the information about the change rate is transmitted through n parameters, it can be expressed in the form of an n-order polynomial about the difference t2-t1 between two time points.) Here, the units of t1 and t2 may be milliseconds, the unit of A may indicate Tc / millisecond, and the unit of B may be Tc / millisecond^2. That is, A may indicate N TA,common How much Tc changes every 1 millisecond, and B can indicate N TA,common The rate of change of the value is how much Tc changes per 1 millisecond.

[0536] [Fifth embodiment]

[0537] The fifth embodiment provides a method and a device in which the base station sends K offset , which is a parameter used to determine the timing at which the UE sends the second signal in response to the first signal sent by the base station to the UE.

[0538] The base station sends a first signal and indicates the time point at which the UE sends a second signal corresponding to the first signal through higher layer signaling and DCI. For example, a PDSCH is sent, and the HARQ-ACK feedback to the PDSCH can be indicated by the HARQ-ACK timing related indicator of the bit field of the DCI that schedules the PDSCH. However, in satellite communications, the delay time between the UE and the base station is very large, and therefore the offset value indicated by the conventional DCI may not indicate the correct timing. Therefore, the base station can send K as an additional timing offset to the UE through the SIB. offset value, and the UE can increase the offset K offset To determine the transmission timing of the second signal (uplink transmission).

[0539] The base station can update K to the UE through RRC signaling in the RRC_connected state after the UE's initial access. offset However, in the case where the update is performed only through RRC signaling, the base station and the UE may have different K values ​​during the time interval for performing RRC reconfiguration. offset In this case, the second signal may not be correctly transmitted and received. To eliminate this ambiguous time interval, the base station may configure multiple K in the UE. offset value, and indicates the configured K through MAC CE offset Therefore, the UE can apply the updated K from a certain point in time after receiving the MAC CE. offset value.

[0540] For example, K offset Candidate values ​​of the value can be configured through RRC signaling according to the index shown in the following Table 28.

[0541] [Table 28]

[0542] index K_offset 0 100 1 120 2 140 3 160 4 180 5 200 6 220 7 240

[0543] Table 28 shows that K is configured at regular intervals through 8 indexes. offset , and various other configurations are possible. When the value of index i is 0, 1, 2, ...2 M -1 and hence the number of values ​​is 2 M When (M corresponds to an integer such as 2, 3, 4, ...) and when K in the case of index i offset The value of Koffset It can be defined as having evenly spaced values, such as for i>0, K offset (i) = K offset (0)+(i-1)*A (A is a positive constant). Of course, the value of M can be variable according to the system configuration, and the value of A can also be variably configured according to the value of M. Further, some indexes in the index can be defined as reserved fields. When K other than the reserved fields offset The maximum value is K offset (i max ), A=(K offset (i max )-K offset (0)) / i max relationship is possible.

[0544] Of course, this is merely an example of being composed of values ​​with uniform differences, and may not generally be composed of values ​​with uniform differences as a whole. For example, values ​​with different differences may be configured according to the index range. m The value can be simply configured as 2 M-1 , or is usually configured as another integer value. )

[0545] 1≤i<i m

[0546] K offset (i) = K offset (0)+(i-1)*A1

[0547] i m ≤i≤i max ,

[0548] K offset (i) = K offset (i m )+(ii m )*A2

[0549] A1 and A2 are different positive constants, and A1 = (K offset (i m )-K offset (0)) / i m , A2=(K offset (i max )-K offset (i m )) / (i max -i m ).

[0550] Afterwards, the base station may transmit the index to the UE in time slot n via MAC CE, and the UE may receive the index in time slot n+k by applying the indicated K offsetAccording to an embodiment of the present disclosure, the value of k may be configured or determined according to the subcarrier spacing.

[0551] [Sixth embodiment]

[0552] A UE supporting a non-terrestrial network (NTN) may also be able to operate in a terrestrial network (TN). In the case where the radio access scheme operating in a terrestrial network (e.g., 3GPP NR) is different from the radio access scheme operating in a satellite network (e.g., 3GPP LTE NB-IoT), the UE may be able to operate by turning on only one radio access scheme, because it is not possible for the UE to turn on different radio access schemes at the same time or because turning them on at the same time is disadvantageous in terms of power consumption. Turning on only the radio access may mean driving at least one of a chip or hardware device or software device that supports the corresponding radio access. In this case, the UE may need a method to determine whether the network to which the UE is to connect is an NTN or a TN.

[0553] Fig.36 is a flow chart for performing satellite network connection of a UE according to an embodiment.

[0554] In operation 3601, the UE may attempt to connect to a terrestrial network and determine that connection to the terrestrial network is not possible. The UE may be able to turn on the relevant wireless connection scheme with priority given to the terrestrial network. In this case, if no synchronization signal or reference signal sent from the terrestrial network is detected, the UE may turn off the wireless connection scheme for the terrestrial network and turn on the wireless connection scheme for the satellite network.

[0555] In operation 3603, the UE may determine the need for satellite network connection. This may be a determination as to whether to activate a wireless connection scheme for a satellite network.

[0556] For example, in the case where a synchronization signal or a reference signal transmitted from a terrestrial network is not detected as in operation 3601, the UE may turn off the wireless connection scheme for the terrestrial network and turn on the wireless connection scheme for the satellite network. Here, the UE may be able to determine whether to turn on the wireless connection scheme for the satellite network through additional information.

[0557] For example, in the case where the UE has hardware capable of receiving GPS signals, the wireless access scheme for the satellite network is enabled only when the GPS signal is captured, and the wireless access scheme for the satellite network is not enabled when the GPS signal is not captured. The UE can determine whether the GPS signal is captured only when the GPS signal reception strength of the UE is greater than or equal to a certain threshold, or when the UE can determine the location information of the UE within a certain error range through the GPS signal.

[0558] In another example, the UE user may be able to independently determine whether to enable a wireless access scheme for a satellite network through the UE, and the conditions for activating the scheme may include that the UE does not receive a terrestrial network signal or that the UE receives a GPS signal. If the above conditions are not met, the scheme may not be activated, so that the UE user cannot enable the wireless access scheme for the satellite network.

[0559] In the case where the wireless access scheme for the satellite network is turned on, in operations 3605 and 3607, the UE can perform a satellite network connection, and when the initial connection is completed and relevant higher layer information is received from the satellite network, the UE can then send and receive control and data information with the satellite.

[0560] The above description is for the case where the wireless access scheme for the terrestrial network and the wireless access scheme for the satellite network are different, but there may also be a case where the wireless access schemes for the terrestrial network and the satellite network are the same. In this case, the above operation and condition determination may not be necessary.

[0561] One of the methods for the UE to distinguish between a terrestrial network and a satellite network is to determine whether satellite-related information is included by system information (system information block (SIB)) received by the UE. Examples of satellite-related information may include satellite position and velocity information, the validity period of the corresponding satellite information, etc. If the above information is not included in the system information, the UE can determine that the network is a terrestrial network. In other words, if the system information received from the network to which the UE is connected includes satellite-related information, the UE can determine that the network is a satellite network, and if the system information does not include satellite-related information, the UE can determine that the network is a terrestrial network.

[0562] From the perspective of a base station or a base station connected to a ground station, it is possible to distinguish whether a UE accessing the corresponding network is a UE accessing a terrestrial network or a UE accessing a satellite network by using the time (or frequency or code or preamble or sequence) resource at which the UE performs an initial connection. For example, in the case where UE A performs an initial connection through resource 1 and UE B performs an initial connection through resource 2, the base station may be able to determine that UE A has performed an initial connection through a terrestrial network and UE B has performed an initial connection through a satellite network. In this case, the base station may be able to distinguish in advance between initial access resources for the terrestrial network and initial access resources for the satellite network. In addition, even if the UE accesses the same satellite network, UEs with different capabilities may be distinguished by a similar method.

[0563] [Seventh embodiment]

[0564] In the following embodiments, a method for performing DMRS bundling (or simultaneous channel estimation) at a receiving end when a UE repeatedly transmits an uplink in a satellite network will be described.

[0565] Fig.37 FIG. 2 is a diagram showing a method for configuring a configured TDW and an actual TDW for simultaneous channel estimation.

[0566] TDW is a time domain window, which represents a time domain interval for performing simultaneous channel estimation on multiple PUSCHs and PUSCH repetition transmissions (or multiple PUCCHs and PUCCH repetition transmissions).

[0567] The channel estimation is described as follows: The base station can indicate through configuration whether the UE will use the same precoding, and using this, the base station can estimate the channel by using DMRS transmissions using the same precoding together, thereby improving the DMRS channel estimation performance.

[0568] In this case, in order to perform simultaneous channel estimation, power consistency and phase continuity must be maintained. In order to maintain the power consistency and phase continuity of the above transmission power, the same transmission power and phase configuration, the same RB configuration and the same MCS configuration are required, and DL transmission and reception and monitoring must not be performed between PUSCH / PUCCH performing simultaneous channel estimation. When power consistency and phase continuity are maintained by the above configuration, simultaneous channel estimation using DMRS of multiple PUSCHs is possible.

[0569] refer to Fig.37 , if the UE is configured by higher layer signaling and L1 signaling as a configured TDW length 'L' = 6 time slots for simultaneous channel estimation from the base station, and simultaneous channel estimation is enabled (3701) in the PUSCH transmission of paired spectrum (FDD configuration), the UE can determine the configured TDW #13702 starting from the first PUSCH transmission time slot or available time slot, and then sequentially determine the configured TDW #2 and the configured TDW #3. In this case, the last one of the configured TDWs can be the last PUSCH time slot where the PUSCH repetition transmission ends.

[0570] Thereafter, the UE may determine the actual TDW based on the determined configured TDW. If event 3703 occurs in the configured TDW #1 3702, the UE may determine the actual TDW #1-1 3704 based on event 3703. In this case, the end of the actual TDW #1-1 3704 may be the PUSCH transmission time slot immediately before event 3703. Thereafter, based on event 3703, the UE may determine whether to configure the actual TDW #1-2 3705 for the next PUSCH transmission.

[0571] If the capability of the UE supports restarting a new actual TDW after event 3703, the UE may apply simultaneous channel estimation by configuring new actual TDW #1-2 for three U time slots 3706 to 1508. On the other hand, in the case where the capability of the UE does not support simultaneous channel estimation after event 3703, the UE may perform channel estimation and decoding for each U time slot 3706 to 1508. Thereafter, the same method may be applied to the configured TDW to determine the actual TDW.

[0572] In another case, if the UE is configured to have a configured TDW length 'L' = 7 time slots for simultaneous channel estimation from the base station through higher layer signaling and L1 signaling, and simultaneous channel estimation is enabled in PUSCH transmission of unpaired spectrum (e.g., TDD configuration: DDDSUDDSUU) (3709), the UE may determine the configured TDW#1 3710 based only on the semi-static DL / UL configuration before the first PUSCH transmission, or the UE may determine the configured TDW#1 3710 by considering the (multiple) RRC configurations that determine the available time slots, the TDRA in the DCI that schedules the PUSCH, the CG configuration, the activation DCI, etc. In this case, the configured TDW#1 3710 and the next configured TDW#2 may be determined by the above information.

[0573] Thereafter, the UE may determine the last PUSCH timeslot at the end of the scheduled PUSCH repetition transmission as the end of the configured TDW. Thereafter, the UE may determine the actual TDW based on the determined configured TDW. When events 3711, 3712 occur in the configured TDW#1 3710, the UE may determine the PUSCH immediately before event 3711 as the end of the actual TDW#1-1 3713 based on event 3711. Thereafter, based on event 3712, the UE may determine whether to configure the actual TDW#1-2 3714 for the next PUSCH transmission after event 3712.

[0574] If the UE capability supports restarting a new actual TDW after event 3712, the UE may apply simultaneous channel estimation by configuring a new actual TDW #1-2 3714 for each of the S slot 3715, the U slot 3716, and the U slot 3717. On the other hand, in the case where the UE capability does not support simultaneous channel estimation after event 3712, the UE may perform channel estimation and decoding for each of the S slot 3715, the U slot 3716, and the U slot 3717. Thereafter, the actual TDW may be determined by applying the above method to the configured TDW in the same manner.

[0575] In the above method, the UE capability for determining the restart of the actual TDW after the event may include a processing time 'T' for restarting the simultaneous channel estimation. For example, in the case where the UE capability supports restarting at a time point 'T' after the event occurs, a new actual TDW may be configured based on a PUSCH configured after the time point 'T' after the event occurs. In this case, channel estimation and decoding may be performed for each PUSCH transmission within the configured 'T' period after the event. In addition, as Fig.37 As shown, in the case where events 3711, 3712 are consecutive, a processing time 'T' may be applied based on the start or end of the event.

[0576] Through the above method, the UE can configure / apply the configured TDW and actual TDW for PUSCH repetition transmission according to paired spectrum / unpaired spectrum.

[0577] In addition, the above events can be considered as one or a combination of the following: DL transmission according to dynamic SFI, PUSCH discard due to cancellation indication (CI), actual TDW exceeding the maximum duration, frequency hopping, precoder cycle, overlap with PUSCH transmission with high priority, configuration of DL reception and DL listening opportunities, and PUSCH transmission power distribution due to CA / DC.

[0578] In addition, in the case of the last PUSCH repetition transmission, the PUSCH that satisfies the configured count (Count) may also be determined according to the Rel-17 PUSCH repetition transmission process.

[0579] In addition, the following case is a case where power consistency and phase continuity for simultaneous channel estimation are not maintained between two repeatedly transmitted PUCCHs or PUSCHs scheduled in a DCI format. The following case may be applied to both a satellite network and a terrestrial network.

[0580] - The case where there is a downlink time slot or downlink reception or downlink listening interval based on tdd-UL-DL-ConfigurationCommon and tdd-UL-DL-ConfigurationDedicated for unpaired spectrum between the corresponding repeated PUCCH or PUSCH

[0581] - The gap between any two consecutive PUSCH transmissions or the gap between any two consecutive PUCCH transmissions exceeds 13 symbols for normal CP or exceeds 11 symbols for extended CP

[0582] - The gap between any two consecutive PUSCH transmissions or the gap between any two consecutive PUCCH transmissions does not exceed 13 symbols, but another uplink transmission is scheduled between two consecutive PUSCH transmissions or two consecutive PUCCH transmissions

[0583] - Cases where a PUSCH transmission is cancelled from the actual transmission by higher layer signaling or L1 signaling

[0584] - Cases where PUCCH transmission is cancelled from actual transmission by higher layer signaling or L1 signaling

[0585] - The case where the precoding (or beam pattern) applied between the repeatedly transmitted PUSCHs is different

[0586] - Provide different transmission power parameters for consecutive PUCCH or PUSCH repetition transmissions

[0587] - Case where uplink timing adjustment occurs based on timing advance commands

[0588] - Frequency hopping occurs

[0589] Unlike terrestrial networks, satellite networks have an extremely long distance between the transmitter and the receiver, and therefore have a long delay time. In addition, in the case of low-orbit or medium-orbit satellites, since the transmitter and the receiver orbit the earth, their relative speeds are different, resulting in Doppler shift. In addition, since satellite networks usually cover a large area with one satellite, the delay time difference between the UE and the satellite can vary from a few milliseconds to tens of milliseconds within the coverage area of ​​one satellite.

[0590] Therefore, in a satellite network, the UE may need a method to perform TA compensation based on the delay time difference, and for this purpose, the satellite network can provide the UE with satellite orbit information as a two-dimensional function according to time through a higher layer signal. Thus, the UE can be able to identify the delay time by comparing its own position with the position of the satellite using its own internal clock and GPS information and information about the speed of light (or radio waves), and use TA to compensate for the delay time. In addition, since the delay time between the satellite and the ground station also changes over time, higher layer signal information can be provided to the UE by composing the delay time in a two-dimensional function manner. Therefore, the UE can apply different TA values ​​to uplink transmission at a specific time.

[0591] For similar reasons, the UE calculates in advance the Doppler shift value that will appear in the frequency in the uplink transmission, pre-compensates it, and applies it during the uplink transmission. Since the relative speed and frequency information between the UE and the satellite must be known in order to calculate the Doppler, the base station can provide the UE with speed information and position information about the satellite in the form of a two-dimensional function. As a result, the UE can know the relative speed between the satellite and the UE and estimate the Doppler shift value. Therefore, the Doppler shift value applied by the UE can change each time the uplink transmission is performed.

[0592] Therefore, in the case where the UE repeatedly transmits uplink control and data information through PUCCH or PUSCH for simultaneous channel estimation, the UE must apply at least the same TA value and Doppler shift value to the repeatedly transmitted PUCCH and PUSCH. Otherwise, from the perspective of the receiving end, the simultaneous channel estimation performance may be degraded.

[0593] In the case where the repeatedly transmitted PUSCH is a granted PUSCH configured without DCI scheduling, the UE may transmit UCI including information indicating whether a separate "same TA value and Doppler shift value" has been applied to the configured granted PUSCH, and this information may be present in the first PUSCH in the repeatedly configured granted PUSCH. Alternatively, in addition to the configured granted PUSCH information, information including information indicating whether the UE has applied the "same TA value and Doppler shift value" may also be transmitted to the base station before repeatedly transmitting the PUCCH or PUSCH. This information may be transmitted via the PUCCH or PUSCH, and may be reported by the UE only if the base station has been allocated resources in advance for transmitting the corresponding information.

[0594] Alternatively, in a satellite network, even if the TA and Doppler shift values ​​applied by the UE for each repeatedly transmitted PUSCH or PUCCH are not exactly the same depending on the base station reception capability, the base station can perform simultaneous channel estimation for the repeatedly transmitted PUSCH and PUCCH within the actual TDW.

[0595] Therefore, when repeatedly transmitting PUSCH or PUCCH, the base station may be able to inform the UE whether the same TA or the same Doppler shift value should be applied within the actual TDW, and this may be transmitted to the UE through a higher layer signal or an L1 signal.

[0596] In the case of being sent as an L1 signal, the information may be included in the DCI for scheduling PUSCH or PUCCH. For example, when the UE repeatedly sends PUSCH or PUCCH, the information whether the same TA or the same Doppler shift value is applied within the actual TDW is sent as an L1 signal, the information may be included in the DCI for scheduling PUSCH or PUCCH. Alternatively, the corresponding information may be added to the DCI format as a field consisting of 1 bit. For example, the following information may be included: if the bit has a value of 1, the same TA or Doppler shift value should be applied, and if the bit has a value of 0, the same TA or Doppler shift value does not need to be applied. Alternatively, it may be determined whether the same TA or the same Doppler shift value is applied depending on the HARQ process value. For example, it may be indicated that if the HARQ process value is 1 to 8, the same TA or the same Doppler shift value should be applied, and if the HARQ process value is 9 to 16, the same TA or the same Doppler shift value does not need to be applied. This is only an example and may be applied in other ways.

[0597] A higher layer signal may indicate whether a specific time or frequency interval may be applied with the same TA or the same Doppler shift value. The time or frequency interval may exist periodically. For example, it may indicate that the same TA or the same Doppler shift value may be applied to the first 5 ms in units of 10 ms. In other words, this is the same as indicating that the same TA or the same Doppler shift value need not be applied to the last 5 ms in units of 10 ms.

[0598] The above-mentioned repetition units of 10ms and 5ms are examples. The time unit or time may be changed to a frequency value and the frequency value may be applied. Alternatively, it may be indicated in a bitmap manner in which interval within a specific interval the UE should apply the same TA or the same Doppler shift value. Alternatively, it may be indicated that the same TA or the same Doppler shift value may be applied only within a specific elevation angle interval between the UE and the satellite. In other words, this is the same as indicating that the same TA or the same Doppler shift value need not be applied except for a specific elevation angle interval between the UE and the satellite.

[0599] The above example has explained the method for indicating whether the same TA or the same Doppler shift value should be applied between repeatedly transmitted PUSCH or PUCCH within the actual TDW. In addition, even if the same TA or Doppler shift value is not applied, the base station can also indicate to the UE that the difference in TA or Doppler shift value between repeatedly transmitted PUSCH or PUCCH should be maintained within a certain range.

[0600] For example, the base station may indicate to the UE that the TA difference between repeatedly transmitted PUSCH or PUCCH within the actual TDW should be within 1us. In this case, in addition to us, the unit may also be indicated as a time unit such as ms, Ts or Tc. In addition, the TA difference between repeatedly transmitted PUSCH or PUCCH within the actual TDW may mean the difference between the maximum TA and the minimum TA applied to all repeatedly transmitted PUSCH or PUCCH within the actual TDW, or may mean the TA difference between two consecutively repeatedly transmitted PUSCH or PUCCH within the actual TDW. Considering that a change in time (or time delay) corresponds to a change in phase (or phase delay), the TA difference may also be understood as a phase difference (or phase difference).

[0601] As another example, it may be indicated that the Doppler shift difference between repeatedly transmitted PUSCH or PUCCH within the actual TDW must be within 5 Hz. In this case, in addition to Hz, the unit may be expressed in ppm (parts per million, one million). In addition, the Doppler shift difference between repeatedly transmitted PUSCH or PUCCH within the actual TDW may mean the difference between the maximum Doppler shift and the minimum Doppler shift applied to all repeatedly transmitted PUSCH or PUCCH within the actual TDW, or may mean the Doppler shift difference between two consecutively repeatedly transmitted PUSCH or PUCCH within the actual TDW.

[0602] After configuring multiple candidate values ​​via a higher layer signal, information indicating the range of the difference in TA or Doppler shift values ​​between PUSCH or PUCCH may be indicated by one of the candidate values ​​via an L1 signal. Alternatively, after configuring one candidate value via a higher layer signal, information indicating the range of the difference in TA or Doppler shift values ​​between PUSCH or PUCCH may indicate via an L1 signal whether the corresponding value is applied. Information about TA or Doppler shift values ​​may be configured separately as different signals. Alternatively, information about TA or Doppler shift values ​​may be configured separately, but whether a specific range value is applied may be indicated in the same L1 signal.

[0603] Table 29 is an embodiment thereof, showing the allowable difference of the Doppler frequency shift applied between two consecutively repeatedly transmitted PUSCHs or PUCCHs within the actual TDW in the DCI field consisting of 2 bits. The meaning of 0 is the same as that of the Doppler frequency shift value that must be kept the same. TA-related information can also be configured in a similar manner to Table 29, and the allowable difference of Doppler and TA can also be indicated by adding a column.

[0604] [Table 29]

[0605] index Maximum allowable Doppler shift difference 0 0 1 1Hz 2 2Hz 3 3Hz

[0606] Fig.38 is a flow chart illustrating the operation of a UE for simultaneous channel estimation of a base station according to an embodiment.

[0607] In operations 3801 and 3803, the UE performs initial access to the satellite network and then receives relevant higher layer signal information for simultaneous channel estimation from the base station. In operation 3805, the UE may perform uplink repetition transmission according to the received information.

[0608] The UE can determine the configured TDW and actual TDW intervals by scheduling higher layer signal information for simultaneous channel estimation and an L1 signal for repeated transmission of PUSCH or PUCCH. In this case, the UE determines whether the TA or Doppler shift value applied between PUSCH or PUCCH to be repeatedly transmitted within the actual TDW interval should be the same by considering the method described in the seventh embodiment, and applies it to the repeated transmission of PUSCH or PUCCH. Alternatively, the UE determines how much difference between the TA or Doppler shift values ​​applied between repeatedly transmitted PUSCH or PUCCH within the actual TDW interval is allowed by considering the method described in the seventh embodiment, and applies the difference between the TA or Doppler shift values ​​to repeated transmission of PUSCH or PUCCH within the allowed range.

[0609] [Eighth Embodiment]

[0610] In the seventh embodiment, the explanation is mainly made from the perspective of the serving link. In the eighth embodiment, the operation of the satellite for simultaneous channel estimation of the base station is explained from the perspective of the feeder link.

[0611] As about Fig.12 As described, the satellite network is mainly composed of a service link and a feeder link, the service link is a link between the satellite and the UE, and the feeder link is a link between the satellite and the ground station (or gateway or base station). Unlike the terrestrial network, in the satellite network, the signal sent by the UE is sent to the base station via the satellite, so in order for the base station to perform simultaneous channel estimation, the TA and Doppler shift between the PUSCH or PUCCH continuously repeatedly sent from the UE within the actual TDW from the satellite to the base station must be the same on the feeder link. In other words, in order for the base station to perform simultaneous channel estimation on the PUSCH or PUCCH repeatedly sent by the UE, the TA or Doppler shift value applied to the PUSCH or PUCCH applied for each repeated transmission must be the same not only on the service link but also on the feeder link. At least, in the case where the TA or Doppler shift value applied in the service link or feeder link is applied differently to the PUSCH or PUCCH, it may be difficult for the base station to perform simultaneous channel estimation.

[0612] Therefore, the satellite needs to determine whether the signal received from the UE is repeatedly transmitted and whether simultaneous channel estimation is required at the base station. For example, in the case where the corresponding signal is repeatedly transmitted and simultaneous channel estimation is required at the base station, the satellite must apply the same TA or the same Doppler frequency shift when transmitting the signal to the base station.

[0613] As another example, the satellite may or may not apply the same TA or the same Doppler shift when transmitting signals to the base station, where the corresponding signals are repeatedly transmitted and simultaneous channel estimation at the base station is not required.

[0614] The above-mentioned satellite may be applicable only to the amplification and forwarding scheme, which simply transmits the signal received from the UE to the base station. In the case of a decode-and-forward scheme in which the satellite demodulates / decodes the signal received from the UE and then encodes / modulates it again, the above-mentioned method may not be applicable because direct simultaneous channel estimation can be performed on the satellite for the signal received from the UE.

[0615] For ease of explanation, the first to eighth embodiments of the present disclosure are divided and described, but since each embodiment includes mutually related operations, the combination of at least two embodiments is also available. In addition, the methods of the various embodiments are not mutually exclusive, and one or more methods can also be performed in combination.

[0616] Fig.39 is a flow chart showing the operation of a UE according to an embodiment. Fig.39 Various changes may be made to the methods shown in the flowcharts of the embodiment. For example, although shown as a series of operations, the various operations in each figure may overlap, occur in parallel, occur in different orders, or occur multiple times. In another example, an operation may be omitted or replaced by another operation.

[0617] refer to Fig.39 , in operation 3910 according to the embodiment, the UE may receive configuration information related to uplink channel repeated transmission through higher layer signaling.

[0618] In operation 3920 according to an embodiment, the UE may perform uplink channel repetition transmission. The UE may transmit a plurality of uplink channels corresponding to the uplink channel repetition transmission in a plurality of time slots based on pre-compensation.

[0619] According to an embodiment, precompensation may be performed to ensure that a phase difference between a phase associated with an uplink channel mapped to a first slot among the plurality of slots and a phase associated with an uplink channel mapped to a second slot among the plurality of slots is within a predefined range.

[0620] According to an embodiment, a predefined range may be used for demodulation reference signal (DM-RS) bundling. DM-RS bundling may be used for uplink channel repetition transmission. For example, if the corresponding predefined range is met, the UE may be configured for DM-RS bundling and transmit a DM-RS to which DM-RS bundling is applied.

[0621] about Fig.39 For more specific details of the operation of the UE shown, reference may be made to the description of the above embodiments.

[0622] Fig.40 is a flow chart showing the operation of a base station according to an embodiment. Fig.40 Various changes may be made to the methods shown in the flowcharts of the embodiment. For example, although shown as a series of operations, the various operations in each figure may overlap, occur in parallel, occur in different orders, or occur multiple times. In another example, an operation may be omitted or replaced by another operation.

[0623] In operation 4010 according to the embodiment, the base station may send configuration information related to uplink channel repeated transmission to the UE through higher layer signaling.

[0624] In operation 4020 according to an embodiment, the base station may repeatedly receive an uplink channel from the UE. The base station may receive a plurality of uplink channels corresponding to repeated transmission of the uplink channel from the UE in a plurality of time slots.

[0625] According to an embodiment, a phase difference between a phase associated with an uplink channel mapped to a first slot among the plurality of slots and a phase associated with an uplink channel mapped to a second slot among the plurality of slots may be included in a predefined range.

[0626] According to an embodiment, a predefined range may be used for demodulation reference signal (DM-RS) bundling. DM-RS bundling may be used for uplink channel repetition transmission. For example, if the corresponding predefined range is met, the base station may configure DM-RS bundling and receive the DM-RS to which DM-RS bundling is applied.

[0627] about Fig.40 For more specific details of the operation of the illustrated base station, reference may be made to the description of the above embodiments.

[0628] The base station, satellite and UE or the transmitting end or the receiving end for performing the embodiments of the present disclosure are described, and the receiver, processor and transmitter of the base station, satellite and UE should operate according to each embodiment.

[0629] More specifically, Fig.39 is a block diagram showing an internal structure of a UE according to an embodiment of the present disclosure.

[0630] like Fig.41 As shown, the UE of the present disclosure may include a UE receiver 4100, a UE transmitter 4120, and a UE processor 4110. Of course, not limited to the above examples, the UE may include more or fewer components. In addition, the UE receiver 4100, the UE transmitter 4120, and the UE processor 4110 may be configured in a single chip.

[0631] In an embodiment of the present disclosure, the UE receiver 4100 and the UE transmitter 4120 may be collectively referred to as a transceiver. The transceiver may send a signal to a base station or a satellite or receive a signal from a base station or a satellite. The signal sent or received by the UE may include control information and data. To this end, the transceiver may include an RF transmitter for up-converting and amplifying the frequency of the transmitted signal, an RF receiver for amplifying and down-converting the frequency of the received signal with low noise, etc. The components of the transceiver are certainly not limited to the RF transmitter and the RF receiver. In addition, the transceiver may receive a signal through a wireless channel, output the signal to the UE processor 4110, and send a signal output from the UE processor 4110 through a wireless channel.

[0632] The UE processor 4110 may control a series of processes so that the UE operates according to the above-described embodiments of the present disclosure. For example, the UE receiver 4100 may receive signals from a satellite or a ground base station and signals from a GNSS, and the UE processor 4110 may send and receive signals to the base station according to the method described in the present disclosure. Afterwards, the UE transmitter 4120 may use the determined time point to send a signal. In the present disclosure, the UE processor 4110 may be defined as a circuit or a dedicated integrated circuit or at least one processor, but is certainly not limited to the above examples.

[0633] According to an embodiment of the present disclosure, the UE may include a memory (not shown). The memory may store programs and data required for the operation of the UE. In addition, the memory may store control information or data included in a signal obtained by the UE. The memory may include a storage medium such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD, or any combination thereof.

[0634] Fig.42 is a block diagram showing an internal structure of a satellite according to an embodiment of the present disclosure.

[0635] like Fig.42As shown, the satellite of the present disclosure may include a satellite receiver 4200, a satellite transmitter 4220, and a satellite processor 4210. The receiver, transmitter, and processor may be configured in plural form. That is, the satellite may be composed of a receiver and a transmitter for sending signals to and receiving signals from a UE, a transmitter and a receiver for sending signals to and receiving signals from a base station (and a receiver and a transmitter for sending signals to and receiving signals from another satellite). Of course, not limited to the above examples, the satellite may include more or fewer components. In addition, the satellite receiver 4200, the satellite transmitter 4220, and the satellite processor 4210 may be configured in a single chip.

[0636] In an embodiment of the present disclosure, the satellite receiver 4200 and the satellite transmitter 4220 may be collectively referred to as a satellite transceiver. The transceiver may send or receive signals to or from the UE and the base station. Here, the signal may include control information and data. To this end, the transceiver may be composed of an RF transmitter for up-converting and amplifying the frequency of the transmitted signal, an RF receiver for amplifying and down-converting the received signal with low noise, and the like. The components of the transceiver are certainly not limited to the RF transmitter and the RF receiver. In addition, the transceiver may receive a signal through a wireless channel, output the signal to the satellite processor 4210, and transmit the signal output from the satellite processor 4210 through a wireless channel. The satellite processor 4210 may include a compensator (pre-compensator) for compensating for frequency offset or Doppler shift and a device capable of tracking a position through GPS or the like. In addition, the satellite processor 4210 may include a frequency shift function for moving the center frequency of the received signal. The satellite processor 4210 may control a series of processes so that the satellite, the base station, and the UE operate according to the above-described embodiments of the present disclosure. For example, the satellite receiver 4200 may receive a PRACH preamble from the UE and send a RAR according to the PRACH preamble to the UE again, thereby determining to send TA information to the base station. Afterwards, the satellite transmitter 4220 may send a corresponding signal at a determined time point. In the present disclosure, the satellite processor 4210 may be defined as a circuit or a dedicated integrated circuit or at least one processor, but is certainly not limited to the above examples.

[0637] According to an embodiment of the present disclosure, the satellite may include a memory (not shown). The memory may store programs and data required for the operation of the satellite. In addition, the memory may store control information or data included in the signal obtained by the satellite. The memory may include a storage medium such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD, or any combination thereof.

[0638] Fig.43 is a block diagram showing an internal structure of a base station according to an embodiment of the present disclosure.

[0639] like Fig.43 As shown, the satellite of the present disclosure may include a base station receiver 4300, a base station transmitter 4320, and a base station processor 4310. The base station may be a ground base station or part of a satellite. In an embodiment of the present disclosure, the base station receiver 4300 and the base station transmitter 4320 may be collectively referred to as a transceiver. The transceiver may send a signal to or receive a signal from a UE. The signals sent and received with a UE, other base stations, or satellites may include control information and data. To this end, the transceiver may be composed of an RF transmitter for up-converting and amplifying the frequency of the transmitted signal, an RF receiver for amplifying and down-converting the frequency of the received signal with low noise, and the like. The components of the transceiver are certainly not limited to the RF transmitter and the RF receiver. In addition, the transceiver may receive a signal through a wireless channel, output the signal to the base station processor 4310, and send a signal output from the base station processor 4310 through a wireless channel. The base station processor 4310 may control a series of processes so that the base station operates according to the above-mentioned embodiments of the present disclosure. For example, the base station processor 4310 may send a RAR including TA information. In the present disclosure, the base station processor 4310 may be defined as a circuit or a dedicated integrated circuit or at least one processor, but is certainly not limited to the above examples.

[0640] According to an embodiment of the present disclosure, the base station may include a memory (not shown). The memory may store programs and data required for the operation of the base station. In addition, the memory may store control information or data included in a signal obtained by the base station. The memory may include a storage medium such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD, or any combination thereof.

[0641] At the same time, the embodiments of the present disclosure described in this specification and the accompanying drawings are only specific examples presented to easily explain the technical content of the present disclosure and help understand the present disclosure, and are not intended to limit the scope of the present disclosure. That is, it is obvious to a person skilled in the art to which the present disclosure belongs that other modified examples based on the technical ideas of the present disclosure are possible. In addition, each of the embodiments described above can be combined as needed. In addition, the embodiments described above can be implemented in LTE systems, 5G systems, etc. as other modified examples based on the technical ideas of the embodiments described above.

Claims

1. A method performed by a terminal in a communication system, comprising: receiving configuration information related to repeated transmission of a physical uplink shared channel (PUSCH) through higher layer signaling; as well as transmitting a plurality of PUSCHs corresponding to the PUSCH repetition transmission in a plurality of time slots based on pre-compensation, wherein the precompensation is performed to satisfy that a phase difference between a phase associated with a PUSCH mapped to a first time slot of the plurality of time slots and a phase associated with a PUSCH mapped to a second time slot of the plurality of time slots is within a predefined range for demodulation reference signal (DM-RS) bundling, The DM-RS bundling is used for repeated transmission of the PUSCH.

2. The method according to claim 1, wherein: The first time slot and the second time slot are any two consecutive time slots included in the plurality of time slots, or The first time slot is a time slot to which a PUSCH associated with a minimum phase among the plurality of PUSCHs is mapped, and the second time slot is a time slot to which a PUSCH associated with a maximum phase among the plurality of PUSCHs is mapped.

3. The method according to claim 1, wherein: The pre-compensation is used for PUSCH repetitive transmission in a non-terrestrial network (NTN).

4. The method according to claim 1, further comprising transmitting a plurality of DM-RSs to which the DM-RS bundling is applied, in, Configuration information for the DM-RS bundling is received through the higher layer signaling. The method according to claim 1 , further comprising sending, by the terminal, capability information related to supporting the pre-compensation.

6. A terminal in a communication system, comprising: Transceiver; as well as a processor, connected to the transceiver, Wherein, the processor is configured to: receiving configuration information related to physical uplink shared channel (PUSCH) repetitive transmission via higher layer signaling; and transmitting a plurality of PUSCHs corresponding to the PUSCH repetition transmission in a plurality of time slots based on pre-compensation, wherein the precompensation is performed to satisfy that a phase difference between a phase associated with a PUSCH mapped to a first time slot of the plurality of time slots and a phase associated with a PUSCH mapped to a second time slot of the plurality of time slots is within a predefined range for demodulation reference signal (DM-RS) bundling, The DM-RS bundling is used for repeated transmission of the PUSCH.

7. The terminal according to claim 6, wherein: The first time slot and the second time slot are any two consecutive time slots included in the plurality of time slots, or The first time slot is a time slot to which a PUSCH associated with a minimum phase among the plurality of PUSCHs is mapped, and the second time slot is a time slot to which a PUSCH associated with a maximum phase among the plurality of PUSCHs is mapped.

8. The terminal according to claim 6, wherein: The pre-compensation is used for PUSCH repetitive transmission in a non-terrestrial network (NTN).

9. The terminal according to claim 6, wherein: The processor is configured to transmit a plurality of DM-RSs to which the DM-RS bundling is applied, The configuration information for the DM-RS bundling is received via the higher layer signaling.

10. The terminal according to claim 6, wherein: The processor is configured to allow the terminal to transmit capability information related to supporting the pre-compensation.

11. A method performed by a base station in a communication system, comprising: Sending configuration information related to repeated transmission of a physical uplink shared channel (PUSCH) to the terminal through higher layer signaling; as well as receiving a plurality of PUSCHs corresponding to the PUSCH repetition transmission from the terminal in a plurality of time slots, wherein a phase difference between a phase associated with a PUSCH mapped to a first time slot of the plurality of time slots and a phase associated with a PUSCH mapped to a second time slot of the plurality of time slots is included in a predefined range for demodulation reference signal (DM-RS) bundling, The DM-RS bundling is used for repeated transmission of the PUSCH.

12. The method according to claim 11, wherein: The first time slot and the second time slot are any two consecutive time slots included in the plurality of time slots, or The first time slot is a time slot to which a PUSCH associated with a minimum phase among the plurality of PUSCHs is mapped, and the second time slot is a time slot to which a PUSCH associated with a maximum phase among the plurality of PUSCHs is mapped.

13. The method according to claim 11, further comprising receiving, by the terminal, capability information related to supporting pre-compensation, in, The pre-compensation is associated with the phase difference being included in the predefined range.

14. A base station in a communication system, comprising: Transceiver; as well as a processor, connected to the transceiver, Wherein, the processor is configured to: Sending configuration information related to repeated transmission of a physical uplink shared channel (PUSCH) to the terminal through higher layer signaling; and receiving a plurality of PUSCHs corresponding to the PUSCH repetition transmission from the terminal in a plurality of time slots, wherein a phase difference between a phase associated with a PUSCH mapped to a first time slot of the plurality of time slots and a phase associated with a PUSCH mapped to a second time slot of the plurality of time slots is included in a predefined range for demodulation reference signal (DM-RS) bundling, The DM-RS bundling is used for repeated transmission of the PUSCH.

15. The base station according to claim 14, wherein: The processor is configured to allow the terminal to receive capability information related to supporting the pre-compensation, The pre-compensation is related to the phase difference being included in the predefined range.

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