Method and apparatus for transmitting / receiving multicast and broadcast in satellite communication system

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting higher data transmission rates. The disclosure provides a method and an apparatus for performing uplink and downlink transmission if satellite communication is supported in a wireless communication system.

Description

Method and device for transmitting and receiving multicast and broadcast in a satellite communication system

[0001] The present disclosure relates to the operation of a terminal and a base station in a satellite communication system. Specifically, the present disclosure relates to a method for transmitting and receiving multicast and broadcast information in a satellite communication system, and a device capable of performing the same.

[0002] To meet the increasing demand for wireless data traffic since the commercialization of 4G communication systems, efforts are being made to develop improved 5G communication systems, or pre-5G communication systems. For this reason, 5G communication systems, or pre-5G communication systems, are also called beyond 4G networks or post-LTE systems. To achieve high data rates, 5G communication systems are being considered for implementation in ultra-high frequency (mmWave) bands (e.g., 60 GHz bands). To mitigate radio path loss and increase the transmission range of radio waves in ultra-high frequency bands, beamforming, massive MIMO, full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and large-scale antenna technologies are being discussed in 5G communication systems. In addition, to improve the network of the system, technologies such as evolved small cells, advanced small cells, cloud radio access networks (cloud RAN), ultra-dense networks, device-to-device communication (D2D), wireless backhaul, moving networks, cooperative communication, CoMP (Coordinated Multi-Points), and interference cancellation are being developed in 5G communication systems.In addition, advanced coding modulation (ACM) methods such as FQAM (Hybrid FSK and QAM Modulation) and SWSC (Sliding Window Superposition Coding), as well as advanced access technologies such as FBMC (Filter Bank Multi Carrier), NOMA (non-orthogonal multiple access), and SCMA (sparse code multiple access) are being developed in 5G systems.

[0003] Meanwhile, the Internet is evolving from a human-centric network where humans create and consume information to an Internet of Things (IoT) network where information is exchanged and processed between distributed components, such as objects. The Internet of Everything (IoE) is also emerging, combining IoT technologies with big data processing technologies, such as those connected to cloud servers. To implement the IoT, technological elements such as sensing technologies, wireless and wired communication and network infrastructure, service interface technologies, and security technologies are required. Recently, research is being conducted on technologies such as sensor networks, Machine-to-Machine (M2M), and Machine-Type Communication (MTC) for connecting objects. In the IoT environment, intelligent IT (Internet Technology) services can be provided that collect and analyze data generated from connected objects to create new value for human life. IoT can be applied to areas such as smart homes, smart buildings, smart cities, smart or connected cars, smart grids, healthcare, smart appliances, and advanced medical services through the convergence and integration of existing IT (information technology) technologies with various industries.

[0004] Accordingly, various attempts are being made to apply 5G communication systems (also known as New Radio (NR)) to IoT networks. For example, technologies such as sensor networks, machine-to-machine (M2M), and machine-type communication (MTC) are being implemented using 5G communication techniques such as beamforming, MIMO, and array antennas. The application of cloud RAN, a big data processing technology described above, can also be considered an example of the convergence of 3eG and IoT technologies.

[0005] As described above and with the development of wireless communication systems, various services have become available, and methods for providing these services smoothly are required.

[0006] The disclosed embodiments provide a device and method capable of effectively providing services in a mobile communication system. Specifically, a method for effectively transmitting and receiving multicast and / or broadcast signals in a communication system utilizing satellite communications and a device capable of performing the same are proposed.

[0007] The present invention, in order to solve the above problems, is characterized in that it includes a step of receiving cell-specific slot offset information from a base station; a step of receiving terminal-specific slot offset information from the base station; a step of receiving downlink control information for scheduling downlink data from the base station; a step of determining a slot for transmitting HARQ-ACK (hybrid automatic repeat request - acknowledgment) information for the downlink data based on whether the downlink data is multicast data; and a step of transmitting the HARQ-ACK information in the slot.

[0008] Alternatively, a method performed by a terminal of a communication system using a non-terrestrial network comprises the steps of: transmitting cell-specific slot offset information to the terminal; transmitting terminal-specific slot offset information to the terminal; transmitting downlink control information for scheduling downlink data to the terminal; and receiving HARQ-ACK (hybrid automatic repeat request - acknowledgment) information for the downlink data in a slot, wherein the slot is characterized in that it is based on whether the downlink data is multicast data.

[0009] Or, in a method performed by a terminal of a communication system using a non-terrestrial network, the method comprises: a transceiver; and a control unit configured to receive cell-specific slot offset information from a base station, receive terminal-specific slot offset information from the base station, receive downlink control information for scheduling downlink data from the base station, determine a slot for transmitting HARQ-ACK (hybrid automatic repeat request - acknowledgment) information for the downlink data based on whether the downlink data is multicast data, and transmit the HARQ-ACK information in the slot.

[0010] Or, in a method performed by a terminal of a communication system using a non-terrestrial network, the method comprises: a transceiver; and a control unit configured to transmit cell-specific slot offset information to the terminal, transmit terminal-specific slot offset information to the terminal, transmit downlink control information for scheduling downlink data to the terminal, and receive HARQ-ACK (hybrid automatic repeat request - acknowledgment) information for the downlink data in a slot, wherein the slot is characterized in that the slot is based on whether the downlink data is multicast data.

[0011] The disclosed embodiments provide devices and methods capable of effectively providing services in a mobile communication system. In particular, based on at least one embodiment of the present disclosure, multicast and / or broadcast signal transmission and reception can be efficiently performed in a system utilizing satellite communications.

[0012] FIG. 1 is a diagram illustrating an example of the basic structure of the time-frequency domain, which is a radio resource domain in which data or control channels are transmitted in a 5G system.

[0013] FIG. 2 is a diagram illustrating an example of a frame, subframe, and slot structure in a 5G system.

[0014] Figure 3 is a diagram illustrating an example of bandwidth portion settings in a 5G system.

[0015] FIG. 4 is a diagram illustrating an example of a basic unit of time and frequency resources that constitute a downlink control channel that can be used in a 5G system.

[0016] FIG. 5 is a diagram illustrating an example of a process in which a terminal generates a Type-1 (semi-static) HARQ-ACK codebook in a 5G system.

[0017] FIG. 6 is a diagram illustrating an example of a process in which a terminal generates a Type-2 (dynamic) HARQ-ACK codebook in a 5G system.

[0018] FIG. 7 is a diagram illustrating an example of the Earth orbital period of a communication satellite according to the altitude or height of the satellite according to one embodiment of the present disclosure.

[0019] FIG. 8 is a diagram showing an example of a satellite-terminal information transmission and reception process in a satellite network according to one embodiment.

[0020] FIG. 9 is a diagram illustrating an example of a satellite communication according to one embodiment of the present disclosure in which multiple terminals receive a multicast PDSCH and transmit HARQ-ACK feedback therefor.

[0021] FIG. 10 is a diagram illustrating an example of a method for determining an uplink signal transmission slot based on downlink signal reception by a terminal according to one embodiment of the present disclosure.

[0022] FIG. 11 is a diagram illustrating an example of a method by which a base station determines an uplink signal reception slot based on downlink signal reception according to one embodiment of the present disclosure.

[0023] FIG. 12 is a diagram illustrating an example of an operation for determining whether a terminal reports HARQ-ACK information according to one embodiment of the present disclosure.

[0024] FIG. 13 is a diagram illustrating an example of an operation of a base station depending on whether a terminal reports HARQ-ACK information according to an embodiment of the present disclosure.

[0025] FIG. 14 is a diagram illustrating the structure of a terminal in a wireless communication system according to an embodiment of the present disclosure.

[0026] FIG. 15 is a diagram illustrating the structure of a base station in a wireless communication system according to an embodiment of the present disclosure.

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

[0028] In describing the embodiments, descriptions of technical details that are well known in the technical field to which the present disclosure pertains and are not directly related to the present disclosure will be omitted. This is to ensure that the gist of the present disclosure is conveyed more clearly without obscuring it by omitting unnecessary explanations.

[0029] For the same reason, some components in the attached drawings are exaggerated, omitted, or schematically depicted. Furthermore, the dimensions of each component do not entirely reflect its actual size. Identical or corresponding components in each drawing are assigned the same reference numbers.

[0030] The advantages and features of the present disclosure, and methods for achieving them, will become clearer with reference to the embodiments described below in detail together with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below and may be implemented in various different forms. These embodiments are provided only to ensure that the disclosure of the present disclosure is complete and to fully inform those skilled in the art of the scope of the disclosure, and the present disclosure is defined only by the scope of the claims. Like reference numerals designate like elements throughout the specification. In addition, when describing the present disclosure, if a specific description of a related function or configuration is determined to unnecessarily obscure the gist of the present disclosure, the detailed description thereof will be omitted. In addition, the terms described below are terms defined in consideration of the functions of the present disclosure, and may vary depending on the intention or custom of the user or operator. Therefore, the definitions should be made based on the contents throughout the specification.

[0031] Hereinafter, a base station is an entity that performs resource allocation of a terminal, and may be at least one of a gNode B, an eNode B, a Node B, a BS (Base Station), a wireless access unit, a base station controller, or a node on a network. A terminal may include a UE (user equipment), an MS (mobile station), a cellular phone, a smartphone, a computer, a subscriber station, a remote terminal, a wireless terminal, a receive point, a user device, or a multimedia system capable of performing a communication function. For convenience, the term 'terminal' is used in various embodiments of the present disclosure to indicate a device that accesses a base station, regardless of whether the terminal should be considered a mobile device (such as a mobile phone or a smartphone) or a fixed device (such as a desktop computer or a vending machine).

[0032] In the present disclosure, downlink (DL) refers to a wireless transmission path for a signal transmitted from a base station to a terminal, and uplink (UL) refers to a wireless transmission path for a signal transmitted from a terminal to a base station. While the embodiments of the present disclosure will be described below using 5G or next-generation systems as examples, the embodiments of the present disclosure may also be applied to other communication systems with similar technical backgrounds or channel types. For example, this may include LTE or LTE-A mobile communications and mobile communication technologies developed after 5G. Accordingly, the embodiments of the present disclosure may be applied to other communication systems with some modifications without significantly departing from the scope of the present disclosure, as determined by a person skilled in the art. The contents of the present disclosure are applicable to FDD and TDD systems.

[0033] In addition, the present disclosure may be applied to other communication systems with some modifications within a scope that does not significantly deviate from the scope of the present disclosure, as judged by a person having skilled technical knowledge.

[0034] At this time, it will be understood that each block of the processing flowchart drawings and combinations of the flowchart drawings can be performed by computer program instructions. These computer program instructions can be installed in a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing equipment, so that the instructions executed by the processor of the computer or other programmable data processing equipment create a means for performing the functions described in the flowchart block(s). These computer program instructions can also be stored in a computer-available or computer-readable memory that can direct a computer or other programmable data processing equipment to implement the functions in a specific manner, so that the instructions stored in the computer-available or computer-readable memory can also produce a manufactured item that includes an instruction means for performing the functions described in the flowchart block(s). Since the computer program instructions may be installed on a computer or other programmable data processing device, a series of operational steps may be performed on the computer or other programmable data processing device to create a computer-executable process, and the instructions that cause the computer or other programmable data processing device to perform the steps for performing the functions described in the flowchart block(s) may also provide steps for performing the functions described in the flowchart block(s).

[0035] Additionally, each block may represent a module, segment, or portion of code that contains one or more executable instructions for performing a specific logical function(s). It should also be noted that in some alternative implementation examples, the functions described in the blocks may occur out of order. For example, two blocks depicted in succession may actually be executed substantially concurrently, or the blocks may sometimes be executed in reverse order, depending on their respective functions.

[0036] Here, the term '~ unit' used in this embodiment means software or hardware components such as FPGA (field programmable gate array) or ASIC (application specific integrated circuit), and the '~ unit' performs certain roles. However, the '~ unit' is not limited to software or hardware. The '~ unit' may be configured to be on an addressable storage medium or may be configured to play one or more processors. Accordingly, as an example, the '~ unit' includes components such as software components, object-oriented software components, class components, and task components, processes, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functions provided within the components and '~ units' may be combined into a smaller number of components and '~ units' or further separated into additional components and '~ units'. Additionally, the components and '~parts' may be implemented to activate one or more CPUs within a device or secure multimedia card. In addition, in an embodiment, the '~parts' may include one or more processors.

[0037] Wireless communication systems are evolving from providing voice-oriented services in the early days to broadband wireless communication systems that provide high-speed, high-quality packet data services, such as communication standards such as 3GPP's HSPA (High Speed ​​Packet Access), LTE (Long Term Evolution or E-UTRA (Evolved Universal Terrestrial Radio Access)), LTE-Advanced (LTE-A), LTE-Pro, 3GPP2's HRPD (High Rate Packet Data), UMB (Ultra Mobile Broadband), and IEEE's 802.16e.

[0038] The LTE system, a representative example of the above-mentioned broadband wireless communication system, employs the OFDM (orthogonal frequency division multiplexing) method in the downlink and the SC-FDMA (single carrier frequency division multiple access) method in the uplink. The above-mentioned multiple access method typically allocates and operates the time-frequency resources for transmitting data or control information to each user so that they do not overlap, that is, so as to achieve orthogonality, thereby enabling each user's data or control information to be distinguished.

[0039] As a future communication system beyond LTE, 5G communication systems must be able to freely reflect the diverse needs of users and service providers. Therefore, they must support services that simultaneously satisfy these diverse requirements. Services being considered for 5G communication systems include enhanced Mobile Broadband (eMBB), massive machine type communication (mMTC), and ultra-reliable low-latency communication (URLLC).

[0040] eMBB aims to provide data transmission rates that are significantly higher than those supported by existing LTE, LTE-A, or LTE-Pro. For example, in a 5G communication system, eMBB must be able to support a peak data rate of 20 Gbps in the downlink and a peak data rate of 10 Gbps in the uplink from a single base station. Furthermore, 5G communication systems must simultaneously provide the peak data rate and an increased user-perceived data rate for terminals. To meet these requirements, improvements in various transmission and reception technologies, including improved multi-input, multi-output (MIMO) transmission technology, are required. Furthermore, while LTE transmits signals using a maximum 20 MHz transmission bandwidth in the 2 GHz band, 5G communication systems can meet the data transmission rates required by 5G communication systems by utilizing a wider frequency bandwidth than 20 MHz in the 3-6 GHz or higher 6 GHz bands.

[0041] At the same time, mMTC is being considered to support application services such as the Internet of Things (IoT) in 5G communication systems. To efficiently provide the Internet of Things, mMTC requires support for large-scale terminal connection within a cell, improved terminal coverage, improved battery life, and reduced terminal costs. The Internet of Things provides communication functions by attaching various sensors and various devices, so a large number of terminals (e.g., 1,000,000 terminals / km) are required within a cell. 2 ) must be able to support. Furthermore, terminals supporting mMTC are likely to be located in shadow areas not covered by cells, such as basements of buildings, due to the nature of the service, and thus may require wider coverage than other services provided by 5G communication systems. Terminals supporting mMTC must be composed of low-cost terminals, and because it is difficult to frequently replace the terminal's battery, a very long battery life time, such as 10 to 15 years, may be required.

[0042] Finally, URLLC refers to a cellular-based wireless communication service used for a specific purpose (mission-critical). For example, services such as remote control of robots or machinery, industrial automation, unmanned aerial vehicles, remote health care, and emergency alerts can be considered. Therefore, the communication provided by URLLC must provide very low latency and very high reliability. For example, a service supporting URLLC must satisfy an air interface latency of less than 0.5 milliseconds and at the same time, a 10 -5The following packet error rate (PER) requirements apply. Therefore, for services supporting URLLC, 5G systems must provide a smaller Transmit Time Interval (TTI) than other services. Simultaneously, design considerations may require the allocation of extensive resources in the frequency band to ensure communication link reliability.

[0043] The three services of a 5G system—eMBB, URLLC, and mMTC—can be multiplexed and transmitted within a single system. To meet the differing requirements of each service, different transmission and reception techniques and parameters can be used. Of course, the 5G system is not limited to the three services described above.

[0044] Below, the frame structure of the 5G system is described in more detail with reference to drawings.

[0045] FIG. 1 is a diagram illustrating an example of the basic structure of the time-frequency domain, which is a radio resource domain in which data or control channels are transmitted in a 5G system.

[0046] In Figure 1, the horizontal axis represents the time domain and the vertical axis represents the frequency domain. The basic unit of resources in the time and frequency domains is a resource element (RE, 101), which can be defined as 1 OFDM symbol (102) on the time axis and 1 subcarrier (103) on the frequency axis. In the frequency domain (For example, 12) consecutive REs can form one resource block (RB, 104).

[0047] FIG. 2 is a diagram illustrating an example of a frame, subframe, and slot structure in a 5G system.

[0048] Figure 2 illustrates an example of a structure of a frame (frame, 200), a subframe (subframe, 201), and a slot (slot, 202). One frame (200) can be defined as 10 ms. One subframe (201) can be defined as 1 ms, and therefore one frame (200) can be composed of a total of 10 subframes (201). One slot (202, 203) can be defined as 14 OFDM symbols (i.e., the number of symbols per slot =14). 1 subframe (201) may be composed of one or more slots (202, 203), and the number of slots (202, 203) per 1 subframe (201) may vary depending on the setting value μ (204, 205) for the subcarrier spacing. In the example of Fig. 2, the cases where μ = 0 (204) and μ = 1 (205) as the subcarrier spacing setting value are illustrated. When μ = 0 (204), 1 subframe (201) may be composed of one slot (202), and when μ = 1 (205), 1 subframe (201) may be composed of two slots (203). That is, the number of slots per 1 subframe ( ) may vary, and accordingly the number of slots per frame ( ) may vary. Depending on the subcarrier spacing setting μ and can be defined as shown in Table 1 below.

[0049] μ 0141011142022144043148084141601651432032

[0050] Next, the bandwidth part (BWP) setting in the 5G communication system will be explained in detail with reference to the drawing.

[0051] Figure 3 is a diagram illustrating an example of bandwidth portion settings in a 5G system.

[0052] FIG. 3 illustrates an example in which the UE bandwidth (300) is set to two bandwidth portions, namely, bandwidth portion #1 (BWP#1, 301) and bandwidth portion #2 (BWP#2, 302). The base station can set one or more bandwidth portions to the UE, and can set the information in Table 2 below for each bandwidth portion.

[0053] BWP ::= SEQUENCE {bwp-Id BWP-Id,(bandwidth part identifier)locationAndBandwidth INTEGER (1..65536),(bandwidth part location)subcarrierSpacing ENUMERATED {n0, n1, n2, n3, n4, n5},(subcarrier spacing)cyclicPrefix ENUMERATED { extended}(cyclic prefix)}

[0054] Of course, the above example is not limited, and in addition to the above configuration information, various parameters related to the bandwidth portion may be configured for the terminal. The above information may be transmitted from the base station to the terminal via upper layer signaling, for example, radio resource control (RRC) signaling. At least one of the configured bandwidth portions may be activated. Whether or not the configured bandwidth portion is activated may be semi-statically transmitted from the base station to the terminal via RRC signaling or dynamically transmitted via downlink control information (DCI).

[0055] According to some embodiments, a terminal before RRC connection can be configured with an initial bandwidth portion (initial BWP) for initial access from a base station through a master information block (MIB). More specifically, the terminal can receive, during the initial access phase, configuration information about a control region (control resource set, CORESET) and a search space where a PDCCH for receiving system information (which may correspond to remaining system information, RMSI or system information block 1, SIB1) required for initial access can be transmitted through the MIB. The control region and search space configured by the MIB may each be regarded as an identity (ID) 0. The base station can notify the terminal of configuration information such as frequency allocation information, time allocation information, and numerology for control region #0 through the MIB. In addition, the base station can notify the terminal of configuration information about a monitoring cycle and location (occasion) for control region #0, i.e., configuration information for search space #0, through the MIB. The terminal may regard the frequency region set as control region #0 obtained from the MIB as the initial bandwidth portion for initial access, and through the set initial bandwidth portion, the terminal may receive the PDSCH (physical downlink shared channel) through which the SIB is transmitted. In addition to receiving the SIB, the initial bandwidth portion may also be utilized for other system information (OSI), paging, and random access. In this case, the identifier (ID) of the initial bandwidth portion may be regarded as 0.

[0056] The settings for the bandwidth supported by the above 5G can be used for various purposes.

[0057] In some embodiments, when the bandwidth supported by a terminal is smaller than the system bandwidth, this can be supported through bandwidth portion configuration. For example, the base station can configure the bandwidth portion frequency location (configuration information 2) for the terminal, thereby allowing the terminal to transmit and receive data at a specific frequency location within the system bandwidth.

[0058] Additionally, in some embodiments, a base station may configure multiple bandwidth segments for a terminal to support different numerologies. For example, to support data transmission and reception using both 15 kHz and 30 kHz subcarrier spacing for a given terminal, two bandwidth segments may be configured with subcarrier spacings of 15 kHz and 30 kHz, respectively. The different bandwidth segments may be frequency division multiplexed, and when data is to be transmitted and received using a specific subcarrier spacing, the bandwidth segment configured for that subcarrier spacing may be activated.

[0059] Furthermore, in some embodiments, the base station may configure bandwidth portions with different bandwidth sizes for the terminal for the purpose of reducing power consumption of the terminal. For example, if the terminal supports a very large bandwidth, such as 100 MHz, and constantly transmits and receives data using that bandwidth, very large power consumption may occur. In particular, monitoring unnecessary downlink control channels using a large bandwidth of 100 MHz in a situation where there is no traffic may be very inefficient in terms of power consumption. To reduce power consumption of the terminal, the base station may configure a bandwidth portion with a relatively small bandwidth, such as 20 MHz, for the terminal. In a situation where there is no traffic, the terminal can perform monitoring operations in the 20 MHz bandwidth portion, and when data is generated, it can transmit and receive data using the 100 MHz bandwidth portion according to the instructions of the base station.

[0060] Next, we will explain the SS (synchronization signal) / PBCH block in the 5G system.

[0061] An SS / PBCH block may refer to a physical layer channel block consisting of a PSS (primary SS), SSS (secondary SS), and PBCH. Specifically, it is as follows.

[0062] - PSS: A signal that serves as a reference for downlink time / frequency synchronization and provides some information about the cell ID.

[0063] - SSS: It serves as a reference for downlink time / frequency synchronization and provides remaining cell ID information not provided by PSS. Additionally, it can serve as a reference signal for PBCH demodulation.

[0064] - PBCH: Provides essential system information required for transmission and reception of data and control channels on a terminal. Essential system information may include search space-related control information indicating radio resource mapping information for the control channel, and scheduling control information for a separate data channel that transmits system information.

[0065] - SS / PBCH Block: An SS / PBCH block is composed of a combination of PSS, SSS, and PBCH. One or more SS / PBCH blocks can be transmitted within a 5ms period, and each transmitted SS / PBCH block can be distinguished by an index.

[0066] The terminal can detect PSS and SSS in the initial access stage and decode PBCH. It can obtain MIB from PBCH and configure control region #0 therefrom. The terminal can monitor control region #0 assuming that the selected SS / PBCH block and the demodulation reference signal (DMRS) transmitted in control region #0 are quasi-co-located (QCL). The terminal can receive system information through downlink control information transmitted in control region #0. The terminal can obtain RACH (random access channel) related configuration information required for initial access from the received system information. The terminal can transmit PRACH (physical RACH) to the base station considering the selected SS / PBCH index, and the base station receiving the PRACH can obtain information about the SS / PBCH block index selected by the terminal. The base station can know which block among each SS / PBCH block the terminal has selected and that the control region #0 associated with it is being monitored.

[0067] Next, we will specifically explain downlink control information (DCI) in 5G systems.

[0068] In a 5G system, scheduling information for uplink data (or physical uplink shared channel, PUSCH) or downlink data (or physical downlink shared channel, PDSCH) is transmitted from a base station to a terminal via DCI. The terminal can monitor a fallback DCI format and a non-fallback DCI format for the PUSCH or PDSCH. The fallback DCI format can be composed of fixed fields defined between the base station and the terminal, and the non-fallback DCI format can include configurable fields.

[0069] DCI can be transmitted over the physical downlink control channel (PDCCH) after going through the channel coding and modulation process. A cyclic redundancy check (CRC) is attached to the DCI message payload, and the CRC can be scrambled with a radio network temporary identifier (RNTI) corresponding to the identity of the UE. Different RNTIs can be used depending on the purpose of the DCI message, such as UE-specific data transmission, power control command, or random access response. That is, the RNTI is not transmitted explicitly, but is included in the CRC calculation process. When the UE receives a DCI message transmitted over the PDCCH, it verifies the CRC using the assigned RNTI. If the CRC verification result is correct, the UE can determine that the message was transmitted to the UE.

[0070] For example, a DCI scheduling a PDSCH for system information (SI) may be scrambled with SI-RNTI. A DCI scheduling a PDSCH for a random access response (RAR) message may be scrambled with RA-RNTI. A DCI scheduling a PDSCH for a paging message may be scrambled with P-RNTI. A DCI notifying a slot format indicator (SFI) may be scrambled with SFI-RNTI. A DCI notifying a transmit power control (TPC) may be scrambled with TPC-RNTI. A DCI scheduling a UE-specific PDSCH or PUSCH may be scrambled with C-RNTI (cell RNTI).

[0071] DCI format 0_0 can be used as a fallback DCI for scheduling PUSCH, in which case the CRC can be scrambled with C-RNTI. DCI format 0_0 with the CRC scrambled with C-RNTI can include, for example, the information in Table 3 below.

[0072] - Identifier for DCI formats - [1] bit- Frequency domain resource assignment - [ ] bits- Time domain resource assignment - X bits- Frequency hopping flag - 1 bit.- Modulation and coding scheme - 5 bits- New data indicator - 1 bit- Redundancy version - 2 bits- HARQ process number - 4 bits- TPC command for scheduled PUSCH - [2] bits- UL / SUL indicator (uplink / supplementary UL indicator) - 0 or 1 bit

[0073] DCI format 0_1 ​​can be used as a fallback DCI for scheduling PUSCH, in which case the CRC can be scrambled with C-RNTI. DCI format 0_1 ​​with the CRC scrambled with C-RNTI can include, for example, the information in Table 4 below.

[0074] - Carrier indicator - 0 or 3 bits- UL / SUL indicator - 0 or 1 bit- Identifier for DCI formats - [1] bits- Bandwidth part indicator - 0, 1, or 2 bits- Frequency domain resource assignment- For resource allocation type 0 bits- For resource allocation type 1, bits- Time domain resource assignment -1, 2, 3, or 4 bits- VRB-to-PRB mapping (virtual resource block-to-physical resource block mapping) - 0 or 1 bit, only for resource allocation type 1.○ 0 bit if only resource allocation type 0 is configured;○ 1 bit otherwise.- Frequency hopping flag - 0 or 1 bit, only for resource allocation type 1.○ 0 bit if only resource allocation type 0 is configured;○ 1 bit otherwise.- Modulation and coding scheme - 5 bits- New data indicator - 1 bit- Redundancy version - 2 bits- HARQ process number - 4 bits- 1st downlink assignment index (first downlink allocation index)- 1 or 2 bits○ 1 bit for semi-static HARQ-ACK codebook (semi-static HARQ-ACK In case of codebook);○ 2 bits for dynamic HARQ-ACK codebook with single HARQ-ACK codebook(When dynamic HARQ-ACK codebook is used with single HARQ-ACK codebook).- 2nd downlink assignment index (2nd downlink assignment index) - 0 or 2 bits○ 2 bits for dynamic HARQ-ACK codebook with two HARQ-ACK sub-codebooks(When dynamic HARQ-ACK codebook is used with two HARQ-ACK sub-codebooks);○ 0 bit otherwise.TPC command for scheduled PUSCH - 2 bits- SRS resource indicator (SRS resource indicator) -. or bits○ bits for non-codebook based PUSCH transmission; ○ bits for codebook based PUSCH transmission. - Precoding information and number of layers - up to 6 bits - Antenna ports - up to 5 bits - SRS request - 2 bits - CSI request - 0, 1, 2, 3, 4, 5, or 6 bits - CBG transmission information - 0, 2, 4, 6, or 8 bits - PTRS-DMRS association (Phase Tracking Reference Signal - Demodulation Reference Signal Association) - 0 or 2 bits - beta_offset indicator - 0 or 2 bits - DMRS sequence initialization - 0 or 1 bit

[0075] DCI format 1_0 can be used as a fallback DCI for scheduling PDSCH, in which case the CRC can be scrambled with C-RNTI. DCI format 1_0 with the CRC scrambled with C-RNTI can include, for example, the information in Table 5 below.

[0076] - Identifier for DCI formats - [1] bit- Frequency domain resource assignment -[ ] bits- Time domain resource assignment - X bits- VRB-to-PRB mapping - 1 bit.- Modulation and coding scheme - 5 bits- New data indicator - 1 bit- Redundancy version - 2 bits- HARQ process number - 4 bits- Downlink assignment index - 2 bits- TPC command for scheduled PUCCH - [2] bits- PUCCH resource indicator (physical uplink control channel, PUCCH) - 3 bits- PDSCH-to-HARQ feedback timing indicator (PDSCH-to-HARQ feedback timing indicator) - [3] bits

[0077] DCI format 1_1 can be used as a fallback DCI for scheduling PDSCH, in which case the CRC can be scrambled with C-RNTI. DCI format 1_1 with the CRC scrambled with C-RNTI can include, for example, the information in Table 6 below.

[0078] - Carrier indicator - 0 or 3 bits- Identifier for DCI formats - [1] bits- Bandwidth part indicator - 0, 1 or 2 bits- Frequency domain resource assignment○ For resource allocation type 0, bits○ For resource allocation type 1, bits- Time domain resource assignment -1, 2, 3, or 4 bits- VRB-to-PRB mapping - 0 or 1 bit, only for resource allocation type 1.○ 0 bit if only resource allocation type 0 is configured;○ 1 bit otherwise.- PRB bundling size indicator - 0 or 1 bit - Rate matching indicator - 0, 1, or 2 bits - ZP CSI-RS trigger - 0, 1, or 2 bits For transport block 1 (for the first transport block): - Modulation and coding scheme - 5 bits - New data indicator - 1 bit - Redundancy version - 2 bits For transport block 2 (for the second transport block): - Modulation and coding scheme - 5 bits - New data indicator - 1 bit - Redundancy version - 2 bits - HARQ process number - 4 bits - Downlink assignment index - 0 or 2 or 4 bits - TPC command for scheduled PUCCH - 2 bits - PUCCH resource indicator - 3 bits - PDSCH-to-HARQ_feedback timing indicator - 3 bits - Antenna ports - 4, 5, or 6 bits- Transmission configuration indication - 0 or 3 bits- SRS request - 2 bits- CBG transmission information - 0, 2, 4, 6, or 8 bits- CBG flushing out information - 0 or 1 bit- DMRS sequence initialization - 1 bit.

[0079] Below, the downlink control channel in a 5G communication system will be described in more detail with reference to drawings.

[0080] FIG. 3 is a diagram illustrating an example of a control region in which a downlink control channel is transmitted in a 5G system. FIG. 3 illustrates an example in which two control regions (control region #1 (301), control region #2 (302)) are set within a UE bandwidth part (UE bandwidth part, 310) on the frequency axis and within one slot (320) on the time axis. The control regions (301, 302) can be set to specific frequency resources (303) within the entire UE bandwidth part (310) on the frequency axis. The time axis can be set to one or more OFDM symbols, which can be defined as the control region length (control resource set duration, 304). Referring to the illustrated example in FIG. 3, control region #1 (301) is set to a control region length of two symbols, and control region #2 (302) is set to a control region length of one symbol.

[0081] In the aforementioned 5G system, the control region can be established by the base station to the terminal via higher-layer signaling (e.g., system information, MIB, RRC signaling). Establishing a control region for the terminal means providing information such as the control region identifier, the frequency location of the control region, and the symbol length of the control region. For example, this information may include the information in Table 7 below.

[0082] ControlResourceSet ::= SEQUENCE {-- Corresponds to L1 parameter 'CORESET-ID' controlResourceSetId ControlResourceSetId,(Control domain identifier (Identity)) frequencyDomainResources BIT STRING (SIZE (45)),(Frequency axis resource allocation information) duration INTEGER (1..maxCoReSetDuration),(Time axis resource allocation information) cce-REG-MappingType CHOICE {(CCE-to-REG mapping method) interleaved SEQUENCE {reg-BundleSize ENUMERATED {n2, n3, n6},(REG bundle size) precoderGranularity ENUMERATED {sameAsREG-bundle, allContiguousRBs}, interleaverSize ENUMERATED {n2, n3, n6}(interleaver size) shiftIndex INTEGER(0..maxNrofPhysicalResourceBlocks-1) OPTIONAL(Interleaved Shift)},nonInterleaved NULL},tci-StatesPDCCH SEQUENCE(SIZE (1..maxNrofTCI-StatesPDCCH)) OF TCI-StateId OPTIONAL,(QCL setting information)tci-PresentInDCI ENUMERATED {enabled} OPTIONAL, -- Need S}

[0083] In Table 7, the tci-StatesPDCCH (simply named TCI (transmission configuration indication) state) configuration information may include information on one or more SS / PBCH block indices or CSI-RS (channel state information reference signal) indices that are in a QCL (quasi co-located) relationship with the DMRS transmitted in the corresponding control region.

[0084] FIG. 4 is a diagram illustrating an example of a basic unit of time and frequency resources that constitute a downlink control channel that can be used in a 5G system. According to FIG. 4, the basic unit of time and frequency resources that constitute a control channel can be referred to as a REG (resource element group, 403), and a REG (403) can be defined as 1 OFDM symbol (401) on the time axis and 1 PRB (physical resource block, 402) on the frequency axis, i.e., 12 subcarriers. A base station can concatenate REGs (403) to constitute a downlink control channel allocation unit.

[0085] As illustrated in FIG. 4, if the basic unit to which a downlink control channel is allocated in 5G is called a CCE (control channel element, 404), 1 CCE (404) can be composed of multiple REGs (403). Taking the REG (403) illustrated in FIG. 4 as an example, the REG (403) can be composed of 12 REs, and if 1 CCE (404) is composed of 6 REGs (403), 1 CCE (404) can be composed of 72 REs. When a downlink control region is set, the region can be composed of multiple CCEs (404), and a specific downlink control channel can be mapped to one or multiple CCEs (404) and transmitted according to the aggregation level (AL) within the control region. CCEs (404) within the control area are distinguished by numbers, and the numbers of the CCEs (404) can be assigned according to a logical mapping method.

[0086] The basic unit of the downlink control channel illustrated in FIG. 4, that is, the REG (403), may include both the REs to which the DCI is mapped and the areas to which the DMRS (405), which is a reference signal for decoding the REs, is mapped. As shown in FIG. 4, three DMRSs (405) may be transmitted within one REG (403). The number of CCEs required to transmit the PDCCH may be 1, 2, 4, 8, or 16 depending on the aggregation level, and different numbers of CCEs may be used to implement link adaptation of the downlink control channel. For example, when AL = L, one downlink control channel may be transmitted through L CCEs. The terminal must detect a signal without knowing information about the downlink control channel, and a search space representing a set of CCEs is defined for blind decoding. A search space is a set of downlink control channel candidates, consisting of CCEs that a terminal must attempt to decode at a given aggregation level. Since there are multiple aggregation levels, each of which can be a set of 1, 2, 4, 8, or 16 CCEs, a terminal can have multiple search spaces. A search space set can be defined as the set of search spaces at all configured aggregation levels.

[0087] Search spaces can be categorized into common search spaces and UE-specific search spaces. A certain group of UEs, or all UEs, can search the common search space of the PDCCH to receive cell-common control information, such as dynamic scheduling of system information or paging messages. For example, PDSCH scheduling allocation information for transmitting SIBs, including cell operator information, can be received by searching the common search space of the PDCCH. In the case of the common search space, since a certain group of UEs, or all UEs, must receive the PDCCH, it can be defined as a set of pre-arranged CCEs. Scheduling allocation information for UE-specific PDSCH or PUSCH can be received by searching the UE-specific search space of the PDCCH. The UE-specific search space can be defined UE-specifically as a function of the UE's identity and various system parameters.

[0088] In a 5G system, parameters for a search space for PDCCH can be set from a base station to a terminal via higher layer signaling (e.g., SIB, MIB, RRC signaling). For example, the base station can set the number of PDCCH candidates at each aggregation level L, the monitoring period for the search space, the monitoring occasion for each symbol within a slot for the search space, the search space type (common search space or terminal-specific search space), the combination of DCI format and RNTI to be monitored in the corresponding search space, the control region index to be monitored for the search space, etc. to the terminal. For example, the information in Table 8 below can be included.

[0089] SearchSpace ::= SEQUENCE {-- Identity of the search space. SearchSpaceId = 0 identifies the SearchSpace configured via PBCH (MIB) or ServingCellConfigCommon.searchSpaceId SearchSpaceId,(search space identifier)controlResourceSetId ControlResourceSetId,(control space identifier)monitoringSlotPeriodicityAndOffset CHOICE {(monitoring slot level period)sl1 NULL,sl2 INTEGER (0..1),sl4 INTEGER (0..3),sl5 INTEGER (0..4),sl8 INTEGER (0..7),sl10 INTEGER (0..9),sl16 INTEGER (0..15),sl20 INTEGER (0..19)} OPTIONAL,duration(monitoring length) INTEGER (2..2559)monitoringSymbolsWithinSlot BIT STRING (SIZE (14)) OPTIONAL,(슬롘 내 나이스 심보)nrofCandidates SEQUENCE {(집성 별보 PDCCH 이리군 수)aggregationLevel1 ENUMERATED {n0, n1, n2, n3, n4, n5, n6, n8}, aggregationLevel2 ENUMERATED {n0, n1, n2, n3, n4, n5, n6, n8},aggregationLevel4 ENUMERATED {n0, n1, n2, n3, n4, n5, n6, n8},aggregationLevel8 ENUMERATED {n0, n1, n2, n3, n4, n5, n6, n8},aggregationLevel16 ENUMERATED {n0, n1, n2, n3, n4, n5, n6, n8}},searchSpaceType CHOICE {(தமம்ப்புக்குக்க்கு திய்)-- Configures this search space as common search space (CSS) and DCI formats to monitor.common SEQUENCE {(공통이이공성)}ue-Specific SEQUENCE {(단말-특정이이공성)-- Indicates whether the UE monitors in this USS for DCI formats 0-0 and 1-0 or for formats 0-1 and 1-1.formats ENUMERATED {formats0-0-And-1-0, formats0-1-And-1-1},...}.

[0090] Depending on the configuration information, the base station may configure one or more search space sets for the terminal. In some embodiments, the base station may configure search space set 1 and search space set 2 for the terminal, and may configure the terminal to monitor DCI format A scrambled with X-RNTI in search space set 1 in a common search space, and may configure the terminal to monitor DCI format B scrambled with Y-RNTI in search space set 2 in a terminal-specific search space.

[0091] According to the configuration information, one or more search space sets may exist in a common search space or a terminal-specific search space. For example, search space set #1 and search space set #2 may be configured as a common search space, and search space set #3 and search space set #4 may be configured as terminal-specific search spaces.

[0092] In the common search space, the following combinations of DCI formats and RNTIs can be monitored. Of course, the examples below are not limited to these.

[0093] - DCI format 0_0 / 1_0 with CRC scrambled by C-RNTI, CS-RNTI, SP-CSI-RNTI, RA-RNTI, TC-RNTI, P-RNTI, SI-RNTI

[0094] - DCI format 2_0 with CRC scrambled by SFI-RNTI

[0095] - DCI format 2_1 with CRC scrambled by INT-RNTI

[0096] - DCI format 2_2 with CRC scrambled by TPC-PUSCH-RNTI, TPC-PUCCH-RNTI

[0097] - DCI format 2_3 with CRC scrambled by TPC-SRS-RNTI

[0098] In a terminal-specific search space, the following combinations of DCI formats and RNTIs can be monitored. Of course, the examples below are not limited to these examples.

[0099] - DCI format 0_0 / 1_0 with CRC scrambled by C-RNTI, CS-RNTI, TC-RNTI

[0100] - DCI format 1_0 / 1_1 with CRC scrambled by C-RNTI, CS-RNTI, TC-RNTI

[0101] The RNTIs specified may follow the definitions and uses below.

[0102] C-RNTI (cell RNTI): For terminal-specific PDSCH scheduling purposes

[0103] TC-RNTI (temporary cell RNTI): For terminal-specific PDSCH scheduling purposes

[0104] CS-RNTI (configured scheduling RNTI): Used for semi-statically configured terminal-specific PDSCH scheduling.

[0105] RA-RNTI (random access RNTI): Used for PDSCH scheduling in the random access phase.

[0106] P-RNTI (paging RNTI): Used for scheduling PDSCH where paging is transmitted.

[0107] SI-RNTI (system information RNTI): Used for scheduling PDSCH where system information is transmitted.

[0108] INT-RNTI (interruption RNTI): Used to indicate whether pucturing is in progress for PDSCH.

[0109] TPC-PUSCH-RNTI (transmit power control for PUSCH RNTI): Used to indicate power control commands for PUSCH.

[0110] TPC-PUCCH-RNTI (transmit power control for PUCCH RNTI): Used to indicate power control commands for PUCCH.

[0111] TPC-SRS-RNTI (transmit power control for SRS RNTI): Used to indicate power control commands for SRS.

[0112] The aforementioned specified DCI formats may follow the definitions in Table 9 below.

[0113] DCI formatUsage0_0Scheduling of PUSCH in one cell0_1Scheduling of PUSCH in one cell1_0Scheduling of PDSCH in one cell1_1Scheduling of PDSCH in one cell2_0Notifying a group of UEs of the slot format2_1Notifying a group of UEs of the PRB(s) and OFDM symbol(s) where UE may assume no transmission is intended for the UE2_2Transmission of TPC commands for PUCCH and PUSCH2_3Transmission of a group of TPC commands for SRS transmissions by one or more UEs

[0114] In a 5G system, the search space of aggregation level L in a control region p and a search space set s can be expressed as in the following mathematical expression 1.

[0115] [Mathematical Formula 1]

[0116]

[0117] - L: Integration level

[0118] - n CI : Carrier Index

[0119] - n CCE,p : Total number of CCEs existing within the control region p

[0120] - : slot index

[0121] - : Number of PDCCH candidates for aggregation level L

[0122] - = 0, ..., -1: PDCCH candidate index of aggregation level L

[0123] - l = 0, ..., L -1

[0124] - , Y p,-1 = nRNTI≠0, A p = 39827 for p mod 3 = 0, A p = 39829 for p mod 3 = 1, A p = 39839 for p mod 3 = 2, D= 65537

[0125] - n RNTI : Terminal identifier

[0126] The value can be 0 for a common search space.

[0127] In the case of a terminal-specific search space, the value may correspond to a value that changes depending on the terminal's identity (C-RNTI or ID set to the terminal by the base station) and the time index.

[0128] In a 5G system, since multiple search space sets can be configured with different parameters (e.g., parameters in Table 10), the set of search space sets monitored by a terminal at each point in time can be different. For example, if search space set #1 is configured with an X-slot period and search space set #2 is configured with a Y-slot period and X and Y are different, the terminal can monitor both search space set #1 and search space set #2 in a specific slot, or can monitor either search space set #1 or search space set #2 in a specific slot.

[0129] Next, the PDSCH processing procedure time (PDSCH processing procedure time) will be described. When a base station schedules a UE to transmit a PDSCH using DCI format 1_0, 1_1, or 1_2, the UE may require PDSCH processing time to receive the PDSCH by applying the transmission method indicated through the DCI (modulation and coding scheme (MCS), demodulation reference signal-related information, time and frequency resource allocation information, etc.). NR takes this into account and defines the PDSCH processing time. The PDSCH processing time of the UE can follow the following mathematical expression 2.

[0130] [Equation 2]

[0131] T proc,1 = (N1+ d 1,1 + d2)( 2048 + 144) κ2 -μ T c + T ext

[0132] T as described in mathematical formula 2 proc,1 In , each variable can have the following meanings:

[0133] - N1: The number of symbols determined by the UE processing capability 1 or 2 and the numerology μ according to the capability of the terminal. If the UE processing capability is reported as 1 according to the capability report of the terminal, it may have the value of Table 10. If the UE processing capability is reported as 2 and it is set through upper layer signaling that the UE processing capability 2 can be used, it may have the value of Table 11. The numerology μ is determined by the T proc,1 to maximize μ PDCCH , μ PDSCH, μ UL It can correspond to the minimum value among μ PDCCH , μ PDSCH, μ UL Each may mean the numerology of the PDCCH that schedules the PDSCH, the numerology of the scheduled PDSCH, and the numerology of the uplink channel on which HARQ-ACK (hybrid automatic repeat request - acknowledgement) is to be transmitted.

[0134] Table 10 shows the PDSCH processing time when PDSCH processing capability is 1, and Table 11 shows the PDSCH processing time when PDSCH processing capability is 2.

[0135] μPDSCH decoding time N1[symbols]PDSCH mapping type A and B are both in case dmrs-AdditionalPosition = pos0 in DMRS-DownlinkConfig, which is a higher layer signaling.PDSCH mapping type A and B are both in case dmrs-AdditionalPosition = pos0 in DMRS-DownlinkConfig, which is a higher layer signaling, or if the higher layer parameter is not set.08N 1,0 110132172032024

[0136] μPDSCH decoding time N1[symbols]PDSCH mapping type A and B are both in the upper layer signaling DMRS-DownlinkConfig, if dmrs-AdditionalPosition = pos0, 0314.529 for frequency range 1

[0137] - κ: 64

[0138] - T ext : If the terminal uses a shared spectrum channel access method, the terminal is T ext can be calculated and applied to the PDSCH processing time. Otherwise, T ext is assumed to be 0.

[0139] - If l1 indicating the PDSCH DMRS location value is 12, N in Table 10 above 1,0 has a value of 14, otherwise it has a value of 13.

[0140] - For PDSCH mapping type A, if the last symbol of the PDSCH is the i-th symbol in the slot in which the PDSCH is transmitted, and i < 7, then d 1,1 is 7-i, otherwise d 1,1 is 0.

[0141] - d2: When a physical uplink control channel (PUCCH) f having a high priority index and a PUCCH or PUSCH having a low priority index overlap in time, d2 of the PUCCH having the high priority index may be set to a value reported by the terminal. Otherwise, d2 is 0.

[0142] - If PDSCH mapping type B is used for terminal processing capability 1, d 1,1The value can be determined based on the number of symbols L of the scheduled PDSCH and the number d of overlapping symbols between the PDCCH scheduling the PDSCH and the scheduled PDSCH.

[0143] - If L≥7, then d 1,1 = 0.

[0144] - If L≥4 and L≤6, d 1,1 = 7 - L.

[0145] - If L = 3, d 1,1 = min (d, 1).

[0146] - If L = 2, d 1,1 = 3 + d.

[0147] - If PDSCH mapping type B is used for terminal processing capability 2, d 1,1 The value can be determined based on the number of symbols L of the scheduled PDSCH and the number d of overlapping symbols between the PDCCH that schedules the PDSCH and the scheduled PDSCH.

[0148] - If L≥7, then d 1,1 = 0.

[0149] - If L≥4 and L≤6, d 1,1 = 7 - L.

[0150] - If L = 2,

[0151] - If the scheduled PDCCH exists within a CORESET consisting of three symbols, and the CORESET and the scheduled PDSCH have the same start symbol, d 1,1 = 3.

[0152] - If not, d 1,1 = d.

[0153] - For a terminal supporting capability 2 within a given serving cell, the PDSCH processing time according to terminal processing capability 2 can be applied when the terminal sets processingType2Enabled, which is an upper layer signaling for the cell, to enable.

[0154] If the position of the first uplink transmission symbol of PUCCH containing HARQ-ACK information (the position may be considered K1, which is defined as the transmission time of HARQ-ACK, PUCCH resources used for HARQ-ACK transmission, and timing advance effect) is T after the last symbol of PDSCH proc,1 If the first uplink transmission symbol that appears after a time period of T is not started, the terminal must transmit a valid HARQ-ACK message. That is, the terminal must transmit a PUCCH containing a HARQ-ACK only when there is sufficient PDSCH processing time. Otherwise, the terminal cannot provide the base station with valid HARQ-ACK information corresponding to the scheduled PDSCH. The above T proc,1 can be used for both normal and extended CP cases. In case of PDSCH with two PDSCH transmission locations within one slot, d 1,1 is calculated based on the first PDSCH transmission position within the slot.

[0155] Next, the numerology μ in which the scheduled PDCCH is transmitted PDCCH μ, which is the numerology through which the PDSCH scheduled through the corresponding PDCCH is transmitted. PDSCH In case of cross-carrier scheduling with different parameters, N is the PDSCH reception preparation time of the terminal defined for the time interval between the PDCCH and the PDSCH. pdsch Explains about N pdschIt can be as shown in Table 12 below.

[0156] If μ PDCCH < μ PDSCH In this case, the scheduled PDSCH is N from the last symbol of the PDCCH that scheduled the PDSCH. pdsch It cannot be transmitted before the first symbol of the slot that follows the symbol. The transmission symbol of the corresponding PDSCH may include a DM-RS.

[0157] If μ PDCCH > μ PDSCH In this case, the scheduled PDSCH is N from the last symbol of the PDCCH that scheduled the PDSCH. pdsch It can be transmitted from the symbol onwards. The transmission symbol of the corresponding PDSCH can include DM-RS.

[0158] Table 12 shows N according to the scheduled PDCCH subcarrier interval. pdsch It is described.

[0159] μ PDCCH N pdsch [symbols]0415210314

[0160] In LTE and NR, a terminal, while connected to a serving base station, can perform a procedure to report its supported capabilities to the base station. In the description below, this is referred to as a UE capability report.

[0161] A base station can transmit a UE capability inquiry message requesting a capability report to a connected terminal. The message can include a UE capability request for each RAT (radio access technology) type of the base station. The RAT type-specific request can include information on a combination of supported frequency bands, etc. In addition, in the case of the UE capability inquiry message, UE capabilities for multiple RAT types can be requested through a single RRC message container transmitted by the base station, or the base station can include multiple UE capability inquiry messages including UE capability requests for each RAT type and transmit them to the terminal. That is, the UE capability inquiry can be repeated multiple times in one message, and the terminal can configure a corresponding UE capability information message and report it multiple times. In the 5G system, a UE capability request can be made for MR-DC (multi-RAT dual connectivity), including NR, LTE, and EN-DC (E-UTRA - NR dual connectivity). Additionally, the terminal capability inquiry message is typically transmitted initially after the terminal is connected to the base station, but the base station may request it under any conditions when necessary.

[0162] In the above step, the terminal that receives the UE capability report request from the base station configures the terminal capability based on the RAT type and band information requested from the base station. Below is a summary of how the terminal configures the UE capability in the NR system.

[0163] 1. If the UE receives a list of LTE and / or NR bands through a UE capability request from the base station, the UE configures a band combination (BC) for EN-DC and NR SA (stand-alone). That is, it configures a candidate list of BCs for EN-DC and NR SA based on the bands requested to the base station via FreqBandList. In addition, the bands are prioritized in the order listed in FreqBandList.

[0164] 2. If the base station requests UE capability reporting by setting the "eutra-nr-only" flag or the "eutra" flag, the UE completely removes NR SA BCs from the list of configured BC candidates. This operation can only occur when the LTE base station (eNB) requests the "eutra" capability.

[0165] 3. The terminal then removes fallback BCs from the BC candidate list constructed in the above step. Here, a fallback BC is a BC obtained by removing at least one band corresponding to an SCell from a random BC. This step can be omitted because the BC before removing the band corresponding to at least one SCell can already cover the fallback BC. This step also applies to MR-DC, i.e., to LTE bands. The BCs remaining after this step are the final "candidate BC list."

[0166] 4. The terminal selects BCs to report by selecting BCs that match the requested RAT type from the final "candidate BC list" above. In this step, the terminal constructs the supportedBandCombinationList in a predetermined order. That is, the terminal constructs BCs and UE capabilities to report in the order of the preset rat-Type (nr - eutra - nr - eutra). In addition, it constructs a featureSetCombination for the constructed supportedBandCombinationList, and constructs a list of "candidate feature set combinations" from the candidate BC list after removing the list for the fallback BC (which contains capabilities of the same or lower level). The "candidate feature set combinations" above include feature set combinations for both NR and EUTRA-NR BCs, and can be obtained from the feature set combinations of the UE-NR-Capabilities and UE-MRDC-Capabilities containers.

[0167] 5. Also, if the requested rat Type is eutra-nr and has an effect, featureSetCombinations are included in both containers: UE-MRDC-Capabilities and UE-NR-Capabilities. However, the NR feature set is included only in UE-NR-Capabilities.

[0168] After terminal capabilities are configured, the terminal transmits a terminal capability information message containing the terminal capabilities to the base station. Based on the terminal capabilities received from the terminal, the base station then performs appropriate scheduling and transmission / reception management for the terminal.

[0169] Below we describe how to generate a Type 1 (semi-static) codebook that reports HARQ-ACK.

[0170] In a situation where the number of HARQ-ACK PUCCHs that a UE can transmit in a slot is limited to one, when the UE receives a semi-static HARQ-ACK codebook upper configuration, the UE reports a HARQ-ACK codebook including HARQ-ACK information for PDSCH reception or SPS PDSCH release in a slot indicated by the value of the PDSCH-to-HARQ_feedback timing indicator field in DCI format 1_0 or DCI format 1_1. The UE reports the HARQ-ACK information bit value in the HARQ-ACK codebook as NACK in a slot that is not indicated by the PDSCH-to-HARQ_feedback timing indicator field in DCI format 1_0 or DCI format 1_1. If the UE receives an M for candidate PDSCH reception, the UE reports the HARQ-ACK codebook including HARQ-ACK information for PDSCH reception or SPS PDSCH release in a slot indicated by the value of the PDSCH-to-HARQ_feedback timing indicator field in DCI format 1_0 or DCI format 1_1. A,c In cases where only HARQ-ACK information for one SPS PDSCH release or one PDSCH reception is reported, and the reporting is scheduled by DCI format 1_0 including information that the counter DAI (downlink assignment index) field in the PCell indicates 1, the UE determines one HARQ-ACK codebook for the corresponding SPS PDSCH release or the corresponding PDSCH reception.

[0171] Other than that, the HARQ-ACK codebook determination method is followed according to the method described below.

[0172] The set of candidate cases for PDSCH reception in serving cell c is M A,c If so, M is generated in the following [pseudo-code 1] steps A,c can be obtained.

[0173] [Begin pseudo-code 1]

[0174] - Step 1: Set j to 0, M A,c Initialize to an empty set. Initialize k, the HARQ-ACK transmission timing index, to 0.

[0175] - Step 2: Set R as a set of rows in a table containing slot information, start symbol information, number of symbols, or length information to which the PDSCH is mapped. If the PDSCH-capable mapping symbol indicated by each value of R is set to a UL symbol according to the DL and UL settings set in the upper layer, the corresponding row is deleted from R.

[0176] - Step 3-1: If the terminal can receive one unicast PDSCH in one slot and R is not an empty set, the set M A,c Add 1 to .

[0177] - Step 3-2: If the terminal can receive more than one unicast PDSCH in one slot, count the number of PDSCHs that can be allocated to different symbols in the calculated R and multiply that number by M. A,c Add to.

[0178] - Step 4: Increase k by 1 and start again from step 2.

[0179] [End of pseudo-code 1]

[0180] FIG. 5 is a diagram illustrating an example of a process for a terminal to generate a Type-1 (semi-static) HARQ-ACK codebook in a 5G system. Taking the above-described pseudo-code 1 of FIG. 5 as an example, in order to perform HARQ-ACK PUCCH transmission in slot#k(508), all slot candidates that can indicate slot#k(508) and have PDSCH-to-HARQ timing possible are considered. In FIG. 5, it is assumed that HARQ-ACK transmission is possible in slot#k(508) by a PDSCH-to-HARQ timing combination that is possible only for PDSCHs scheduled in slot#n(502), slot#n+1(504), and slot#n+2(506). And, considering the time domain resource configuration information of the schedulable PDSCHs in slots 502, 504, and 506 and the information indicating whether the symbol within the slot is a downlink or an uplink, the maximum number of schedulable PDSCHs for each slot is derived. For example, if 2 PDSCHs are schedulable in slot 502, 3 PDSCHs in slot 504, and 2 PDSCHs in slot 506, the maximum number of PDSCHs included in the HARQ-ACK codebook transmitted in slot 508 is 7 in total. This is called the cardinality of the HARQ-ACK codebook.

[0181] Step 3-2 above within a specific slot is described in detail with reference to Table 13 below. Table 13 shows the default PDSCH time domain resource allocation A for normal CP.

[0182] Row indexdmrs-TypeA-PositionPDSCH mapping typeK0SLEndingOrder12Type A0212131x3Type A0311131x22Type A0210111x3Type A039111x32Type A029101x3Type A038101x42Type A02781x3Type A03681x52Type A02561x3Type A03461x62Type B094122x3Type B010413372Type B04471x3Type B0649282,3Type B057111x92,3Type B05261x102,3Type B092102x112,3Type B0122133x122,3Type A0113131x132,3Type A01661x142,3Type A02451152,3Type B047101x162,3Type B084112x

[0183] Table 13 is the time resource allocation table in which the terminal operates by default before receiving time resource allocation through a separate RRC signal. Note that in addition to indicating the row index value through a separate RRC signal, the PDSCH time resource allocation value is determined by the terminal common RRC signal dmrs-TypeA-Position. In Table 13 above, the ending and order columns are values ​​added separately for convenience of explanation, and may not actually exist. The meaning of the ending column refers to the end symbol of the scheduled PDSCH, and the order column refers to the code position value located within a specific codebook in the semi-static HARQ-ACK codebook. This table is applied to the time resource allocation applied in DCI format 1_0 of the common search area of ​​the PDCCH.

[0184] To determine the HARQ-ACK codebook by calculating the maximum number of non-overlapping PDSCHs within a specific slot, the terminal performs the following steps.

[0185] * Step 1: Find the PDSCH allocation value that ends earliest within the slot among all rows of the PDSCH time resource allocation table. In Table 13, we can see that row index 14 ends earliest. This is marked as 1 in the order column. In addition, other row indices that overlap row index 14 by at least one symbol are marked as 1x in the order column.

[0186] * Step 2: Then, search for the PDSCH allocation value that ends first among the remaining row indices not indicated in the Order column. In Table 13, this corresponds to the row with row index 7 and dmrs-TypeA-Position value 3. In addition, other row indices that overlap with the corresponding row index by at least one symbol are marked as 2x in the Order column.

[0187] * Step 3: Repeat Step 2 and display the order value in increasing order. For example, in Table 13, search for the PDSCH allocation value that ends first among the row indices not displayed in the order column. In Table 13, this corresponds to the row with row index 6 and dmrs-TypeA-Position value 3. In addition, other row indices that overlap with the corresponding row index by at least one symbol are displayed as 3x in the order column.

[0188] * Step 4: If an order is displayed for all row indices, the process ends. The size of the order is the maximum number of PDSCHs that can be scheduled without time overlap within the slot. Scheduling without time overlap means that different PDSCHs are scheduled using TDM.

[0189] In the order column of Table 13, the maximum value of order means the HARQ-ACK codebook size of the corresponding slot, and the order value means the HARQ-ACK codebook point where the HARQ-ACK feedback bit for the corresponding scheduled PDSCH is located. For example, row index 16 in Table 13 means that it exists in the second code position in the semi-static HARQ-ACK codebook with a size of 3. A terminal transmitting HARQ-ACK feedback selects a set of PDSCH reception candidate cases (occasions for candidates PDSCH receptions) in serving cell c as M A,c If so, M is divided into [pseudo-code 1] or [pseudo-code 2] steps. A,c can be obtained. M A,c can be used to determine the number of HARQ-ACK bits that the terminal should transmit. Specifically, M A,c The HARQ-ACK codebook can be constructed using the cardinality of the set.

[0190] As another example, considerations for determining a semi-static HARQ-ACK codebook (or type 1 HARQ-ACK codebook) may include:

[0191] a) on a set of slot timing values ​​K1associated with the active UL BWP

[0192] (a) If the UE is configured to monitor PDCCH for DCI format 1_0 and is not configured to monitor PDCCH for DCI format 1_1 on serving cell c, K1is provided by the slot timing values ​​{1, 2, 3, 4, 5, 6, 7, 8} for DCI format 1_0

[0193] (b) If the UE is configured to monitor PDCCH for DCI format 1_1 for serving cell c, K1is provided by dl-DataToUL-ACK for DCI format 1_1

[0194] b) on a set of row indexes R of a table that is provided either by a first set of row indexes of a table that is provided by PDSCH-TimeDomainResourceAllocationList in PDSCH-ConfigCommon or by Default PDSCH time domain resource allocation A [6, TS 38.214], or by the union of the first set of row indexes and a second set of row indexes, if provided by PDSCH-TimeDomainResourceAllocationList in PDSCH-Config, associated with the active DL BWP and defining respective sets of slot offsets K0, start and length indicators SLIV, and PDSCH mapping types for PDSCH reception as described in [6, TS 38.214]

[0195] c) on the ratio between the downlink SCS configuration μ DL and the uplink SCS configuration μ ULprovided by subcarrierSpacing in BWP-Downlink and BWP-Uplink for the active DL BWP and the active UL BWP, respectively

[0196] d) if provided, on TDD-UL-DL-ConfigurationCommon and TDD-UL-DL-ConfigDedicated as described in Subclause 11.1.

[0197] As another example, the pseudo-code for HARQ-ACK codebook determination could be as follows.

[0198] [Begin pseudo-code 2]

[0199]

[0200]

[0201]

[0202] [pseudo-code 2 end]

[0203] In pseudo-code 2, the location of the HARQ-ACK codebook containing HARQ-ACK information for the DCI indicating DL SPS release is based on the location where the DL SPS PDSCH is received. For example, if the start symbol for transmitting the DL SPS PDSCH starts from the 4th OFDM symbol based on the slot and is 5 symbols long, the HARQ-ACK information including the DL SPS release indicating the release of the corresponding SPS is determined as if a PDSCH starting from the 4th OFDM symbol of the slot in which the DL SPS release is transmitted and having a length of 5 symbols is mapped, and the corresponding HARQ-ACK information is determined through the PDSCH-to-HARQ timing indicator and PUCCH resource indicator included in the control information indicating the DL SPS release. As another example, if the start symbol for transmitting a DL SPS PDSCH starts from the 4th OFDM symbol based on a slot and is 5 symbols long, HARQ-ACK information including a DL SPS release indicating release of the corresponding SPS is determined by assuming that a PDSCH starting from the 4th OFDM symbol of the slot indicated by the TDRA (time domain resource allocation) of the DCI, which is a DL SPS release, and having a length of 5 symbols is mapped, and the corresponding HARQ-ACK information is determined through the PDSCH-to-HARQ timing indicator and PUCCH resource indicator included in the control information indicating the DL SPS release.

[0204] Below we describe how to generate a Type 2 (dynamic) codebook that reports HARQ-ACK.

[0205] The terminal transmits HARQ-ACK information to be transmitted within a PUCCH in slot n based on the PDSCH-to-HARQ_feedback timing value for PUCCH transmission of HARQ-ACK information in slot n for PDSCH reception or SPS PDSCH release and K0, which is transmission slot location information of the PDSCH scheduled in DCI format 1_0 or 1_1. Specifically, for the above-described HARQ-ACK information transmission, the terminal determines the PDSCH-to-HARQ_feedback timing based on the DAI included in the DCI indicating the PDSCH or SPS PDSCH release and the HARQ-ACK codebook of the PUCCH transmitted in the slot determined by K0.

[0206] The above DAI is composed of a counter DAI and a total DAI. The counter DAI is information indicating the position of the HARQ-ACK information corresponding to the PDSCH scheduled in DCI format 1_0 or DCI format 1_1 within the HARQ-ACK codebook. Specifically, the value of the counter DAI within DCI format 1_0 or 1_1 indicates the accumulated value of the PDSCH reception or SPS PDSCH release scheduled by DCI format 1_0 or DCI format 1_1 in a specific cell c. The above-described accumulated value is set based on the PDCCH monitoring occasion and the serving cell where the scheduled DCI exists.

[0207] Total DAI is a value indicating the size of the HARQ-ACK codebook. Specifically, the total DAI value represents the total number of previously scheduled PDSCH or SPS PDSCH releases, including the time at which the DCI was scheduled. Furthermore, Total DAI is a parameter used in a CA (carrier aggregation) situation when HARQ-ACK information on serving cell c also includes HARQ-ACK information for PDSCHs scheduled in other cells, including serving cell c. In other words, there is no total DAI parameter in a system operating with a single cell.

[0208] An example of the operation of the above DAI is illustrated in FIG. 6. FIG. 6 is a diagram illustrating an example of a process in which a terminal generates a Type-2 (dynamic) HARQ-ACK codebook in a 5G system. In FIG. 6, when the terminal transmits a HARQ-ACK codebook selected based on DAI in the nth slot of carrier 0 (602) on PUCCH (620) in a situation in which two carriers are set, the values ​​of counter DAI (C-DAI) and total DAI (T-DAI) indicated by the DCI searched for each PDCCH monitoring time point set for each carrier are shown. First, the DCI searched at m=0 (606) indicates that C-DAI and T-DAI each have a value of 1 (612). The DCI searched at m=1 (608) indicates that C-DAI and T-DAI each have a value of 2 (614). The DCI searched on carrier 0 (c=0, 602) of m=2 (610) indicates that C-DAI has a value of 3 (616). The DCI searched on carrier 1 (c=1, 604) of m=2 (610) indicates that C-DAI has a value of 4 (618). In this case, if carriers 0 and 1 are scheduled at the same monitoring location, both T-DAIs are indicated as 4.

[0209] In FIGS. 5 and 6, the HARQ-ACK codebook determination operates in a situation where only one PUCCH containing HARQ-ACK information is transmitted in one slot. This is called Mode 1. As an example of how one PUCCH transmission resource is determined in one slot, when PDSCHs scheduled in different DCIs are multiplexed and transmitted as one HARQ-ACK codebook in the same slot, the PUCCH resource selected for HARQ-ACK transmission is determined as the PUCCH resource indicated by the PUCCH resource indicator field indicated in the DCI that last scheduled the PDSCH. That is, the PUCCH resource indicated by the PUCCH resource indicator field indicated in the DCI scheduled before the DCI is ignored.

[0210] Mode 2 refers to a case where two or more PUCCHs containing HARQ-ACK information can be transmitted in one slot. The terminal may be able to operate in only Mode 1 (only one HARQ-ACK PUCCH is transmitted in one slot) or only Mode 2 (one or more HARQ-ACK PUCCHs are transmitted in one slot). Alternatively, a terminal that supports both Mode 1 and Mode 2 may be configured by the base station to operate in only one mode through upper signaling, or Mode 1 and Mode 2 may be implicitly determined by DCI format, RNTI, DCI-specific field values, scrambling, etc. For example, PDSCH scheduled with DCI format A and its associated HARQ-ACK information are based on Mode 1, and PDSCH scheduled with DCI format B and its associated HARQ-ACK information are based on Mode 2. Whether the HARQ-ACK codebook described above is semi-static or dynamic is determined by an RRC signal.

[0211] The following describes the operation of multimedia broadcast and multicast services (MBMS). The NR system enables efficient delivery of multicast / broadcast services (MBS). For broadcast communication services, the same service and specific content data are simultaneously provided to all terminals within a geographic area. Broadcast communication services are delivered to terminals using broadcast sessions. UEs can receive broadcast communication services in the RRC_IDLE, RRC_INACTIVE, and RRC_CONNECTED states.

[0212] For multicast communication services, the same service and specific content data are simultaneously provided to a specific set of terminals. Multicast communication services are provided to terminals using multicast sessions. Terminals can receive multicast communication services in the RRC_CONNECTED state using mechanisms such as point-to-point (PTP) and / or point-to-multipoint (PTM) transmission. HARQ feedback / retransmission can be applied to both PTP and PTM transmissions.

[0213] The logical channels used for MBS transmission are as follows:

[0214] - MTCH: A PTM downlink channel that transmits MBS data of either a multicast session or a broadcast session from the network to the UE.

[0215] - DTCH: A PTP channel for transmitting MBS data of a multicast session from the network to the UE.

[0216] - MCCH: A PTM downlink channel used to transmit MBS broadcast control information related to one or more MTCH(s) from the network to the UE.

[0217] The following connections exist between logical channels and transport channels for PTM transmission:

[0218] - MCCH can be mapped to DL-SCH.

[0219] - MTCH can be mapped to DL-SCH.

[0220] The RNTI for PTM transmission is as follows:

[0221] - Terminals can receive different services using the same or different G-RNTIs;

[0222] - Terminals can receive different services using the same or different G-CS-RNTIs.

[0223] The common frequency resource (CFR) configured with the RRCReconfiguration message is defined as a UE-specific "MBS frequency region" with a number of contiguous PRBs limited to the same number as the DL BWP for multicast scheduling. Multicast scheduling may have specific, separate configurations. For example, the base station may provide different configurations to the UE for PDCCH, PDSCH, and SPS than for unicast scheduling. Two HARQ-ACK reporting modes are defined for MBS.

[0224] - In the first HARQ-ACK reporting mode (hereinafter, the first HARQ-ACK mode), if the terminal correctly decodes a transport block (TB) or detects a DCI format indicating SPS PDSCH release, it generates HARQ-ACK information having an ACK value, otherwise it generates HARQ-ACK information having a NACK value.

[0225] - In the second HARQ-ACK reporting mode (hereinafter, the second HARQ-ACK mode), the UE does not transmit a PUCCH containing only HARQ-ACK information having an ACK value. Alternatively, the UE transmits a PUCCH containing HARQ-ACK information having at least one NACK value.

[0226] HARQ-ACK feedback for multicast can be enabled or disabled by upper layer configuration or instruction per G-RNTI or per G-CS-RNTI in DCI scheduled multicast transmissions.

[0227] The following description explains the characteristics of satellite communications (non-terrestrial network, NTN, hereinafter may be used interchangeably with satellite network). Satellites for communication can be classified into low Earth orbit (LEO), middle Earth orbit (MEO), and geostationary Earth orbit (GEO) satellites depending on their orbits. Generally, GEO refers to a satellite with an altitude of approximately 36,000 km, MEO refers to a satellite with an altitude of 5,000 to 15,000 km, and LEO refers to a satellite with an altitude of 500 to 1,000 km. Of course, it is not limited to the above examples. The Earth orbital period varies depending on the altitude of each satellite. For GEO, the Earth orbital period is approximately 24 hours, for MEO, approximately 6 hours, and for LEO, approximately 90 to 120 minutes. Low Earth orbit (~2,000 km) satellites have a relatively low altitude, which may have an advantage in propagation delay (which can be understood as the time it takes for a signal transmitted from a transmitter to reach a receiver) and loss compared to geostationary orbit (36,000 km) satellites.

[0228] FIG. 7 is a diagram illustrating an example of the Earth orbital period of a communication satellite according to the altitude or height of the satellite according to one embodiment of the present disclosure. Assuming that a terminal communicates with a satellite located at an altitude of 1,200 km, the distance between the terminal and the satellite may vary depending on the elevation angle between the satellite and the terminal. For example, if the elevation angle between the satellite and the terminal is 90 degrees, the distance between the terminal and the satellite is 1,200 km, but if the elevation angle between the satellite and the terminal is 10 degrees, the distance between the terminal and the satellite is approximately 3,135 km. Therefore, in satellite communication, even if the terminal is fixed, the distance between the satellite and the terminal may vary due to the satellite's periodic orbit, such as a low-orbit satellite.

[0229] The following describes scheduling in satellite communications. Just like in terrestrial networks, in satellite networks, a base station or satellite transmits a downlink signal to a terminal and receives an uplink signal accordingly. Downlink signals include PDCCH and PDSCH, and uplink signals may include PUCCH and PUSCH. For example, if a base station transmits a PDSCH to a terminal in slot n, the terminal may transmit a PUCCH containing HARQ-ACK information, which is information on whether the decoding was successful, to the base station in slot n+k1. As another example, if a base station transmits a PDCCH to a terminal in slot n, and the PDCCH information includes uplink scheduling information, the terminal may transmit a PUSCH to the base station in the corresponding resource (slot n+k2). The k1 or k2 value indicates a scheduling offset (or slot offset) between the downlink reception signal and the uplink reception signal slot. The reason slot offset values ​​exist is because terminals require time to process downlink signals received from the base station and to process uplink transmissions to be sent to the base station. Therefore, scheduling offsets are required not only in satellite networks but also in terrestrial networks. However, satellite networks, compared to terrestrial networks, may require larger scheduling offset values ​​due to the longer distance between the terminal and the satellite.

[0230] FIG. 8 is a diagram showing an example of a satellite-terminal information transmission and reception process in a satellite network according to an embodiment. In FIG. 8, it is assumed that a base station schedules a PDSCH to be transmitted in slot n (800) and to receive HARQ-ACK information corresponding to the PDSCH in slot n+4 (810). The terminal can receive the PDSCH in slot n (820) after a long delay time, but slot n+4 (830), in which the base station requested HARQ-ACK feedback, is located in a slot much earlier than the downlink due to the TA (timing advance) of the terminal, so the terminal has a problem of transmitting HARQ-ACK information before receiving the PDSCH.

[0231] Here, the reason why the terminal applies TA during uplink transmission is to synchronize the uplink signals received from different terminals from the base station's perspective. If the terminal does not apply TA and individually transmits the uplink signal according to the terminal's downlink resource, the base station has the burden of having to search for the signal blindly because it does not know at what point the corresponding uplink signal will be received for each terminal. However, since the range of values ​​for applying TA is much wider in satellite networks than in terrestrial networks, if the base station does not provide a sufficient offset value between the slot in which the PDSCH is transmitted and received and the slot in which HARQ-ACK information is transmitted and received, a problem such as that shown in FIG. 8 may occur.

[0232] Therefore, to solve this problem, satellite networks provide a separate offset other than the scheduling offset provided by terrestrial networks. The transmission timing of the uplink signal associated with the corresponding downlink signal of the terminal is n + k + k offset, where n is the slot in which the terminal receives the downlink signal. The value of k is a value indicated by at least one of the upper signal or the L1 signal or a combination of them. This value is a parameter that can be commonly applied to both terrestrial and satellite networks. k offset is a parameter that applies only to satellite networks, and k offset = kcell,offset- k UE,offset It consists of kcell,offset, which is a cell common parameter included in SIB and transmitted to terminals within the cell, and is a value set by the base station considering the maximum delay time between the ground station - satellite - terminal. UE,offset is a terminal-specific parameter included in the MAC CE and transmitted to a specific terminal. It is a parameter that takes into account the fact that the delay time between the satellite and the terminal may be different even if they exist within the same cell. kcell,offset can be applied when the downlink signal is PDSCH and the uplink signal is PUCCH or PUSCH containing HARQ-ACK information, as shown in Fig. 8, and can also be applied to the following cases.

[0233] - Scheduling of PUSCH, an uplink signal for downlink signal RAR

[0234] - Retransmission of Message 3, an uplink signal for the downlink signal DCI format 0_0 with CRC scrambled by TC-RNTI.

[0235] - HARQ-ACK PUCCH, an uplink signal for the downlink signal Contention resolution PDSCH (Message 4)

[0236] - Message B PUSCH, an uplink signal for downlink signal Message A PDSCH

[0237] In describing the present disclosure, upper layer signaling may be signaling corresponding to at least one or a combination of one or more of the following signaling.

[0238] - MIB

[0239] - SIB or SIB

[0240] - RRC

[0241] - MAC (medium access control) CE (control element)

[0242] In addition, L1 signaling may be signaling corresponding to at least one or a combination of one or more signaling methods using the physical layer channel or signaling below.

[0243] - PDCCH

[0244] - DCI

[0245] - UE-specific DCI

[0246] - Group common DCI

[0247] - Common DCI

[0248] - Scheduling DCI (e.g. DCI used for scheduling downlink or uplink data)

[0249] - Non-scheduled DCI (e.g. DCI not intended for scheduling downlink or uplink data)

[0250] - PUCCH

[0251] - UCI (uplink control information)

[0252] Additionally, in various embodiments of the present disclosure, the term TA may be used interchangeably with TA information, TA value, or TA index.

[0253] In various embodiments of the present disclosure, data or control information transmitted by a base station to a terminal may be referred to as a first signal, and an uplink signal associated with the first signal may be referred to as a second signal. For example, the first signal may include DCI, UL grant, PDCCH, PDSCH, RAR, etc., and the second signal associated with the first signal may include PUCCH, PUSCH, msg 3, etc.

[0254] Additionally, there may be an association between the first signal and the second signal. For example, if the first signal is a PDCCH containing a UL grant for uplink data scheduling, the second signal corresponding to the first signal may be a PUSCH containing uplink data. Meanwhile, the gap between the timings at which the first and second signals are transmitted and received may be a value predetermined between the terminal and the base station. Alternatively, the gap between the timings at which the first and second signals are transmitted and received may be determined by a value instructed by the base station or transmitted through higher-level signaling.

[0255] <Example 1: Scheduling Offset>

[0256] Satellite communications can enable the transmission of identical data to multiple terminals via multicast services. For example, when transmitting disaster or emergency messages limited to a specific area, utilizing multicast over unicast allows the base station to utilize resources more efficiently.

[0257] FIG. 9 is a diagram illustrating an example of a satellite communication according to an embodiment of the present disclosure in which multiple terminals receive a multicast PDSCH and transmit HARQ-ACK feedback therefor. According to FIG. 9, a base station may transmit a multicast PDSCH in slot n (900), and terminals may transmit HARQ-ACK feedback therefor in different slots. For example, k is the same as 2, but k set to terminal (UE) 1 offset The value is 2, and k is set to terminal (UE) 2. offset This is because the value may be 6. In this case, terminal 1 may transmit HARQ-ACK for multicast PDSCH in slot n+4 (910), and terminal 2 may transmit HARQ-ACK for multicast PDSCH in slot n+8 (920). Therefore, from the base station's perspective, although the same PDSCH was transmitted in slot n, there is a possibility that reception complexity may increase because it must receive PUCCH or PUSCH containing HARQ-ACK information transmitted by terminals in different time resources. The HARQ-ACK feedback may be feedback according to the first HARQ-ACK mode or the second HARQ-ACK mode.

[0258] Therefore, it may be possible for terminals that have received a multicast PDSCH to transmit a PUCCH or PUSCH containing HARQ-ACK information in the same slot through at least one of the following methods or some combination thereof.

[0259] - Method 1: k UE,offset(or terminal-specific offset) is not applied to DCI formats that schedule multicast PDSCH. For example, if DCI format 4_1 and 4_2 are DCI formats that schedule multicast PDSCH, the terminal may receive the PDSCH scheduled through the corresponding DCI format in slot n, and transmit the HARQ-ACK for it in slot n + k + kcell,offset. And, if the terminal receives DCI format 1_0 and 1_1, which are DCI formats that schedule unicast PDSCH, the terminal may receive the PDSCH through the corresponding DCI format in slot n, and transmit the HARQ-ACK for it in slot n + k + kcell,offset- k UE,offset It may be possible to transmit from. In other words, the terminal may select k depending on whether the DCI format it receives schedules a multicast PDSCH or a unicast PDSCH. UE,offset It may be possible to determine whether or not to apply.

[0260] As another example, if DCI format 4_1 and 4_2 are DCI formats for scheduling multicast PDSCH, the terminal can receive PDSCH in slot n through the corresponding DCI format, and transmit HARQ-ACK for it in slot n + k + kcell,offset only when the second HARQ-ACK mode (or reporting mode in which NACK is fed back) is configured. If the first HARQ-ACK transmission mode is configured, if DCI format 4_1 and 4_2 are DCI formats for scheduling multicast PDSCH, the terminal can receive PDSCH in slot n through the corresponding DCI format, and HARQ-ACK for it is transmitted in slot n + k + kcell,offset- k UE,offset It may be possible to transmit from .

[0261] - Method 2: Terminal is k UE,offsetis applied to the DCI format for scheduling unicast PDSCH, and separately, kgroup,offset can be applied to the DCI format for scheduling multicast PDSCH. For example, if DCI format 4_1 and 4_2 are DCI formats for scheduling multicast PDSCH, the terminal receives the PDSCH scheduled through the corresponding DCI format in slot n, and the HARQ-ACK for this is slot n + k + kcell,offset- It may be possible to transmit in kgroup, offset. And, if the terminal receives DCI format 1_0 and 1_1, which are DCI formats for scheduling unicast PDSCH, the terminal receives the PDSCH scheduled through the corresponding DCI format in slot n, and the HARQ-ACK for this is slot n + k + kcell, offset- k UE,offset It may be possible to transmit from. The values ​​of kgroup, offset may be set by a higher-level signal such as RRC or MAC CE, or may be determined by an L1 signal. In other words, the terminal may apply kgroup, offset depending on whether the DCI format it receives schedules a multicast PDSCH or a unicast PDSCH. UE,offset It may be possible to decide whether to apply .

[0262] As another example, if DCI format 4_1 and 4_2 are DCI formats for scheduling multicast PDSCH, the terminal receives the PDSCH scheduled through the corresponding DCI format in slot n, and if the second HARQ-ACK mode (or the reporting mode in which NACK is fed back) is set, the HARQ-ACK for this is slot n + k + kcell,offset- It is possible to transmit in kgroup, offset. If the first HARQ-ACK transmission mode is set and DCI formats 4_1 and 4_2 are DCI formats that schedule multicast PDSCH, the terminal receives the PDSCH scheduled through the corresponding DCI format in slot n, and the HARQ-ACK for this is slot n + k + kcell, offset- k UE,offset It may be possible to transmit from .

[0263] FIG. 10 is a diagram illustrating an example of a method for determining an uplink signal transmission slot based on downlink signal reception by a terminal according to one embodiment of the present disclosure.

[0264] The terminal can use the upper signal information to determine kcell, offset, or k UE,offset Or at least one of kgroup and offset information is received (1000). The upper signal information may correspond to information such as RRC or MAC CE. Thereafter, the terminal receives control information for downlink data scheduling (1010), and applies at least one of the above-described methods to apply a different slot offset value depending on whether the scheduled downlink data is a unicast PDSCH or a multicast PDSCH, and determines an HARQ-ACK feedback transmission resource for reporting the reception result to the corresponding PDSCH (1020). The terminal transmits HARQ-ACK feedback information through a PUCCH or PUSCH in the determined HARQ-ACK feedback transmission resource (1030).

[0265] The above flowchart illustrates exemplary methods that can be implemented according to the principles of the present disclosure, and various modifications may be made to the methods depicted in the flowcharts herein. For example, although depicted as a series of steps, various steps in each drawing may overlap, occur in parallel, occur in different orders, or occur multiple times. In other instances, steps may be omitted or replaced with other steps.

[0266] FIG. 11 is a diagram illustrating an example of a method by which a base station determines an uplink signal reception slot based on downlink signal reception according to one embodiment of the present disclosure.

[0267] The base station determines an offset value to be applied to the terminal according to one of the methods described above (1100). The offset value may be kcell, offset, or k UE,offset Or at least one of kgroup and offset information may correspond. The base station transmits the offset value to the terminal through upper signal information (1110). The upper signal information may correspond to information such as RRC or MAC CE. Thereafter, the base station transmits control information for downlink data scheduling to the terminal (1120), and receives HARQ-ACK feedback information from the terminal in a HARQ-ACK feedback transmission resource related to whether the scheduled downlink data is a unicast PDSCH or a multicast PDSCH (1130). The HARQ-ACK feedback transmission resource is related to a slot offset value to which at least one of the above-described methods is applied depending on whether the downlink data is a unicast PDSCH or a multicast PDSCH.

[0268] The above flowchart illustrates exemplary methods that can be implemented according to the principles of the present disclosure, and various modifications may be made to the methods depicted in the flowcharts herein. For example, although depicted as a series of steps, various steps in each drawing may overlap, occur in parallel, occur in different orders, or occur multiple times. In other instances, steps may be omitted or replaced with other steps.

[0269] <Example 2: Presence or absence of HARQ-ACK reporting>

[0270] In satellite communications, the long distance between the ground station, satellite, and terminal leads to long delays. This delay is longer than in terrestrial networks, requiring a longer time for the base station to transmit a PDSCH to the terminal and receive the corresponding HARQ-ACK information. Therefore, rather than determining whether to retransmit based on the HARQ-ACK information corresponding to the PDSCH, the base station may be able to improve data transmission reliability within a shorter delay by using techniques such as repeating the PDSCH transmission from the beginning without receiving the HARQ-ACK information.

[0271] Accordingly, in satellite communication, it may be possible to determine whether or not to transmit HARQ-ACK information based on the HARQ process ID value included in the DCI format that schedules the PDSCH. For example, it may be possible for the base station to inform in advance by the upper signal downlinkHARQ-FeedbackDisabled whether HARQ-ACK information transmission is required or not for a certain HARQ process ID, and the upper signal downlinkHARQ-FeedbackDisabled may be composed of a 16-bit string if the HARQ process is 4 bits, and may be composed of a 32-bit string if the HARQ process is 5 bits. Alternatively, regardless of the number of HARQ process bits, the upper signal downlinkHARQ-FeedbackDisabled may be composed of a 32-bit string, and depending on the number of HARQ process bits (k), the first 2 k It may be possible to determine that as many bits are applied to each HARQ process.

[0272] If the downlinkHARQ-FeedbackDisabled upper signal is provided to the UE as {100000000000000...}, the UE may not report HARQ-ACK information for the PDSCH scheduled by the DCI format if the HARQ process ID value included in the DCI format is 0. Each bit may be mapped to a respective HARQ process ID, and the HARQ process ID may be mapped to each bit in ascending order of the HARQ process ID. If the bit corresponding to a specific HARQ process ID in downlinkHARQ-FeedbackDisabled is 1, it may indicate not to report HARQ-ACK information corresponding to the PDSCH of the specific HARQ process ID.

[0273] Not reporting the above HARQ-ACK feedback may result in different specific operations depending on the HARQ-ACK codebook type. If the HARQ-ACK codebook type is Type 1 HARQ-ACK codebook, the UE may transmit the HARQ-ACK codebook on the PUCCH or PUSCH by mapping a NACK (or ACK) to the HARQ-ACK codebook position corresponding to the PDSCH regardless of whether the PDSCH decoding is successful. If the HARQ-ACK codebook type is Type 2 HARQ-ACK codebook, the UE may not generate HARQ-ACK information corresponding to the PDSCH (in this case, the HARQ-ACK information for the PDSCH is not included in the HARQ-ACK codebook) or may not multiplex the PUCCH or PUSCH resource (for example, if the UE receives only a PDSCH without HARQ-ACK feedback, the HARQ-ACK codebook is not generated). If the HARQ process ID value included in the DCI format is a value other than 0, the terminal may be able to map HARQ-ACK information for the PDSCH scheduled by the corresponding DCI format to ACK or NACK and multiplex it on PUCCH or PUSCH resources and transmit it to the base station, if the terminal has a Type 1 HARQ-ACK and Type 2 HARQ-ACK codebook. This is hereinafter referred to as a first HARQ-ACK reporting presence / absence determination method.

[0274] In the case of multicast data, it may be necessary to transmit only multicast data without separate HARQ-ACK feedback, similar to broadcast. This is because the resources for receiving HARQ-ACK information for multicast data are likely to increase in proportion to the number of terminals receiving the multicast data. In addition, if the transmission reliability requirements for multicast data are not high, it may be reasonable to transmit only multicast data without HARQ-ACK feedback. Accordingly, it may be possible to add a 1-bit Enabling / Disabling HARQ-ACK feedback indication field to the DCI format that schedules multicast data. If the value of this field indicates 1 (or 0), the terminal may be able to determine that HARQ-ACK feedback is reported for multicast data scheduled in the corresponding DCI format. If the value of this field indicates 0 (or 1), the terminal may be able to determine that HARQ-ACK feedback is not reported for multicast data scheduled in the corresponding DCI format.

[0275] The meaning of not reporting the above HARQ-ACK feedback may specifically vary depending on the HARQ-ACK codebook type. If the HARQ-ACK codebook type is Type 1 HARQ-ACK codebook, the UE may transmit the HARQ-ACK codebook on the PUCCH or PUSCH by mapping a NACK (or ACK) to the HARQ-ACK codebook position corresponding to the PDSCH regardless of whether the PDSCH decoding is successful. If the HARQ-ACK codebook type is Type 2 HARQ-ACK codebook, the UE may not generate HARQ-ACK information corresponding to the PDSCH (in this case, the HARQ-ACK information for the PDSCH is not included in the HARQ-ACK codebook) or may not multiplex the PUCCH or PUSCH resource (for example, if the UE receives only a PDSCH without HARQ-ACK feedback, the HARQ-ACK codebook is not generated). The 1-bit Enabling / Disabling HARQ-ACK feedback indication field may be enabled if a separate upper signal harq-FeedbackEnablerMulticast indicates DCI-based HARQ-ACK Enabling / Disabling. This is referred to as the second HARQ-ACK reporting presence / absence determination method.

[0276] Because the methods for determining whether HARQ-ACK information reporting is supported in satellite communications differ from those for determining whether HARQ-ACK information is supported in multicast communications, it is necessary to determine which of these methods should be applied in situations where multicast communications are supported in satellite communications. Support may be provided using at least one of the following methods, or some combination thereof.

[0277] * Method 1-1: It may be possible to apply the first HARQ-ACK reporting presence / absence determination method to both DCI formats that schedule multicast and unicast PDSCHs. For example, it may be possible to apply the downlinkHARQ-FeedbackDisabled upper signal to DCI format 4_1 or 4_2. Accordingly, the terminal may be able to determine whether HARQ-ACK information is reported according to the reception of the corresponding multicast PDSCH based on the HARQ process ID provided (indicated) in DCI format 4_1 or 4_2. Accordingly, when the multicast service operates in a terrestrial network band, the terminal and the base station may be able to operate based on the second HARQ-ACK reporting presence / absence determination method. On the other hand, when the multicast service operates in a satellite network band, the terminal and the base station may be able to operate based on the first HARQ-ACK reporting presence / absence determination method.

[0278] * Method 1-2: It may be possible to apply the second HARQ-ACK reporting presence / absence determination method to both DCI formats that schedule multicast and unicast PDSCHs. For example, it may be possible to apply the Enabling / disabling HARQ-ACK feedback indication field to DCI format 1_1 or 1_2. Accordingly, the terminal may be able to determine whether to report HARQ-ACK information according to unicast PDSCH reception based on the value of the Enabling / disabling HARQ-ACK feedback indication field included in DCI format 1_1 or 1_2. Accordingly, if the terminal is a terminal that supports a multicast service in a satellite network, the base station may be able to apply the second HARQ-ACK reporting presence / absence determination method. On the other hand, if the terminal is a terminal that does not support a multicast service in a satellite network, the base station may be able to apply the first HARQ-ACK reporting presence / absence determination method.

[0279] * Method 2-1: It may be possible to apply both the first HARQ-ACK reporting determination method and the second HARQ-ACK reporting determination method. In this case, the following four situations may occur.

[0280] - Case 1: When HARQ process X is instructed to perform HARQ-ACK reporting by the upper signal downlinkHARQ-FeedbackDisabled and when the Enabling / disabling HARQ-ACK feedback indication field of DCI is instructed (set) with the HARQ-ACK reporting value.

[0281] - Case 2: When HARQ process X is indicated not to perform HARQ-ACK reporting by the upper signal downlinkHARQ-FeedbackDisabled and when the Enabling / disabling HARQ-ACK feedback indication field of DCI is indicated with the HARQ-ACK non-reporting value.

[0282] - Case 3: When HARQ process X is indicated not to perform HARQ-ACK reporting by the upper signal downlinkHARQ-FeedbackDisabled and when the Enabling / disabling HARQ-ACK feedback indication field of DCI is indicated with the HARQ-ACK reporting value.

[0283] - Case 4: When HARQ process X is indicated to perform HARQ-ACK reporting by the upper signal downlinkHARQ-FeedbackDisabled and when the Enabling / disabling HARQ-ACK feedback indication field of DCI is indicated with the HARQ-ACK non-reporting value.

[0284] Among the above Cases, Case 1 and Case 2 mean that both the first HARQ-ACK report presence / absence determination method and the second HARQ-ACK report presence / absence determination method provide the same information, and when satellite communication supports multicast communication, it may be possible to allow only Case 1 and Case 2. In other words, when Method 2-1 is applied to both the base station and the terminal, it may be possible to allow only Case 1 and Case 2, and regard Case 3 and Case 4 as error cases. Regarding them as error cases means that the base station does not support Case 3 and Case 4, or when Case 3 and Case 4 occur, the terminal may determine that the corresponding scheduling information is incorrect and ignore it.

[0285] Alternatively, when Case 3 or Case 4 occurs, the terminal may be able to prioritize the first HARQ-ACK reporting determination method or the second HARQ-ACK reporting determination method. Prioritizing the first HARQ-ACK reporting determination method means that only the first HARQ-ACK reporting determination method is applied instead of the second HARQ-ACK reporting determination method. Prioritizing the second HARQ-ACK reporting determination method means that only the second HARQ-ACK reporting determination method is applied instead of the first HARQ-ACK reporting determination method.

[0286] Alternatively, if at least one of the first HARQ-ACK report presence / absence determination method and the second HARQ-ACK report presence / absence determination method for Cases 1 to 4 provides information indicating to perform HARQ-ACK reporting, the terminal may be able to determine to report HARQ-ACK feedback for the multicast PDSCH. Alternatively, if at least one of the first HARQ-ACK report presence / absence determination method and the second HARQ-ACK report presence / absence determination method for Cases 1 to 4 provides information indicating not to perform HARQ-ACK reporting, the terminal may be able to determine to not report HARQ-ACK feedback for the multicast PDSCH.

[0287] FIG. 12 is a diagram illustrating an example of an operation for determining whether a terminal reports HARQ-ACK information according to one embodiment of the present disclosure.

[0288] A terminal receives configuration information on whether to report HARQ-ACK information for a PDSCH through upper layer signaling from a base station. The configuration information may include at least one of downlinkHARQ-FeedbackDisabled or harq-FeedbackEnablerMulticast (1200). Thereafter, the terminal receives a DCI format for scheduling a PDSCH (1210). The DCI format may be a DCI format that supports multicast communication, and may be DCI format 4_1 or 4_2. However, the present invention is not limited to the DCI format disclosed above. The received DCI format may include an Enabling / Disabling HARQ-ACK feedback indication field. The PDSCH may be a multicast PDSCH, but the present invention is not limited thereto.

[0289] The terminal determines whether to feed back HARQ-ACK information for the scheduled PDSCH using at least one combination of methods 1-1, 1-2, or 2-1 described above (1220). If the terminal feeds back HARQ-ACK information for the scheduled PDSCH, the terminal generates HARQ-ACK information for the PDSCH, includes it in a HARQ-ACK codebook, and transmits it to the base station on PUCCH or PUSCH. If the terminal does not feed back HARQ-ACK information for the scheduled PDSCH, the operation of the terminal may follow the operation described above. Alternatively, the terminal may regard the configuration according to the upper layer signaling and DCI format as an error case and, for example, ignore the received DCI format (1230).

[0290] The above flowchart illustrates exemplary methods that can be implemented according to the principles of the present disclosure, and various modifications may be made to the methods depicted in the flowcharts herein. For example, although depicted as a series of steps, various steps in each drawing may overlap, occur in parallel, occur in different orders, or occur multiple times. In other instances, steps may be omitted or replaced with other steps.

[0291] FIG. 13 is a diagram illustrating an example of an operation of a base station depending on whether a terminal reports HARQ-ACK information according to an embodiment of the present disclosure.

[0292] The base station transmits configuration information to the terminal via upper layer signaling regarding whether to report HARQ-ACK information for the PDSCH (1300). The configuration information may include at least one of downlinkHARQ-FeedbackDisabled or harq-FeedbackEnablerMulticast. The configuration information may be based on a combination of at least one of the above-described methods 1-1, 1-2, or 2-1.

[0293] Thereafter, the base station transmits a DCI format for scheduling a PDSCH and transmits the scheduled PDSCH (1310). The DCI format may be a DCI format that supports multicast communication, and may be DCI format 4_1 or 4_2. However, the present invention is not limited to the DCI format disclosed above. The received DCI format may include an Enabling / Disabling HARQ-ACK feedback indication field. The PDSCH may be a multicast PDSCH, but the present invention is not limited thereto. The setting of the Enabling / Disabling HARQ-ACK feedback indication field may be based on a combination of at least one of the above-described methods 1-1, 1-2, or 2-1.

[0294] The base station receives or does not receive HARQ-ACK information for the PDSCH from the terminal depending on whether HARQ-ACK information is reported (1320).

[0295] The above flowchart illustrates exemplary methods that can be implemented according to the principles of the present disclosure, and various modifications may be made to the methods depicted in the flowcharts herein. For example, although depicted as a series of steps, various steps in each drawing may overlap, occur in parallel, occur in different orders, or occur multiple times. In other instances, steps may be omitted or replaced with other steps.

[0296] The first and second embodiments described above can be combined to enable operations of a terminal and a base station. For example, an uplink signal can be transmitted in a slot determined according to a scheduling offset determined according to the first embodiment, and if the uplink signal is HARQ-ACK information, HARQ-ACK information to be fed back can be determined based on the second embodiment.

[0297] FIG. 14 is a diagram illustrating the structure of a terminal in a wireless communication system according to an embodiment of the present disclosure.

[0298] Referring to FIG. 14, the terminal may include a transceiver, which refers to a terminal receiving unit (1400) and a terminal transmitting unit (1410), a memory (not shown), and a terminal processing unit (1405, or a terminal control unit or processor). Depending on the communication method of the terminal described above, the transceiver units (1400, 1410), the memory, and the terminal processing unit (1405) of the terminal may operate. However, the components of the terminal are not limited to the examples described above. For example, the terminal may include more or fewer components than the components described above. In addition, the transceiver unit, the memory, and the processor may be implemented in the form of a single chip.

[0299] A transceiver unit can transmit and receive signals to and from a base station. The signals may include control information and data. To this end, the transceiver unit may include an RF transmitter that up-converts and amplifies the frequency of a transmitted signal, and an RF receiver that low-noise amplifies and down-converts the frequency of a received signal. However, this is only one embodiment of the transceiver unit, and the components of the transceiver unit are not limited to the RF transmitter and RF receiver.

[0300] Additionally, the transceiver can receive a signal through a wireless channel and output it to the processor, and transmit a signal output from the processor through the wireless channel.

[0301] Memory can store programs and data necessary for the terminal's operation. Furthermore, memory can store control information or data included in signals transmitted and received by the terminal. Memory can be comprised of a storage medium, such as ROM, RAM, a hard disk, CD-ROM, or DVD, or a combination of such storage media. Furthermore, there can be multiple memories.

[0302] Additionally, the processor can control a series of processes to enable the terminal to operate according to the aforementioned embodiments. For example, the processor can receive DCI consisting of two layers and control components of the terminal to simultaneously receive multiple PDSCHs. There may be multiple processors, and the processors can perform terminal component control operations by executing programs stored in memory.

[0303] FIG. 15 is a diagram illustrating the structure of a base station in a wireless communication system according to an embodiment of the present disclosure.

[0304] Referring to FIG. 15, the base station may include a transceiver, which refers to a base station receiver (1500) and a base station transmitter (1510), a memory (not shown), and a base station processor (1505, or a base station control unit or processor). Depending on the communication method of the base station described above, the transceiver (1500, 1510), the memory, and the base station processor (1505) of the base station may operate. However, the components of the base station are not limited to the examples described above. For example, the base station may include more or fewer components than the components described above. In addition, the transceiver, the memory, and the processor may be implemented in the form of a single chip.

[0305] The transceiver can transmit and receive signals with the terminal. Here, the signals may include control information and data. To this end, the transceiver may be configured with an RF transmitter that up-converts and amplifies the frequency of a transmitted signal, and an RF receiver that low-noise amplifies and down-converts the frequency of a received signal. However, this is only one embodiment of the transceiver, and the components of the transceiver are not limited to the RF transmitter and RF receiver.

[0306] Additionally, the transceiver can receive a signal through a wireless channel and output it to the processor, and transmit the signal output from the processor through the wireless channel.

[0307] The memory can store programs and data necessary for the operation of the base station. Furthermore, the memory can store control information or data included in signals transmitted and received by the base station. The memory can be comprised of a storage medium, such as ROM, RAM, a hard disk, CD-ROM, or DVD, or a combination of such storage media. Furthermore, there can be multiple memories.

[0308] The processor can control a series of processes to enable the base station to operate according to the embodiments of the present disclosure described above. For example, the processor can configure two layers of DCIs containing allocation information for multiple PDSCHs and control each component of the base station to transmit them. There may be multiple processors, and the processors can perform component control operations of the base station by executing programs stored in memory.

[0309] The methods according to the embodiments described in the claims or specification of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

[0310] When implemented in software, a computer-readable storage medium storing one or more programs (software modules) may be provided. The one or more programs stored in the computer-readable storage medium are configured for execution by one or more processors within an electronic device. The one or more programs include instructions that cause the electronic device to execute methods according to the embodiments described in the claims or specification of the present disclosure.

[0311] These programs (software modules, software) may be stored in random access memory, non-volatile memory including flash memory, read only memory (ROM), electrically erasable programmable read only memory (EEPROM), magnetic disc storage device, compact disc ROM (CD-ROM), digital versatile discs (DVDs) or other forms of optical storage device, magnetic cassette. Or, they may be stored in a memory configured as a combination of some or all of these. In addition, each configuration memory may be included in multiple numbers.

[0312] Additionally, the program may be stored on an attachable storage device that is accessible via a communication network, such as the Internet, an intranet, a local area network (LAN), a wide local area network (WLAN), a storage area network (SAN), or a combination thereof. Such a storage device may be connected to a device performing an embodiment of the present disclosure via an external port. Additionally, a separate storage device on the communication network may be connected to a device performing an embodiment of the present disclosure.

[0313] In the specific embodiments of the present disclosure described above, components included in the invention are expressed in the singular or plural form, depending on the specific embodiment presented. However, the singular or plural expressions are selected to suit the presented situation for convenience of explanation, and the present disclosure is not limited to singular or plural components. Components expressed in the plural form may be composed of singular elements, or components expressed in the singular form may be composed of plural elements.

[0314] Meanwhile, the embodiments of the present disclosure disclosed in this specification and drawings are merely specific examples to easily explain the technical contents of the present disclosure and to help understand the present disclosure, and are not intended to limit the scope of the present disclosure. In other words, it will be apparent to those skilled in the art to which the present disclosure pertains that other modifications based on the technical idea of ​​the present disclosure are possible. In addition, the above-mentioned respective embodiments can be combined and operated with each other as needed. For example, parts of one embodiment of the present disclosure and another embodiment can be combined with each other to operate a base station and a terminal. For example, parts of the first embodiment and the second embodiment of the present disclosure can be combined with each other to operate a base station and a terminal.

[0315] Meanwhile, the order of description in the drawings explaining the method of the present invention does not necessarily correspond to the order of execution, and the order of precedence may be changed or executed in parallel.

[0316] Alternatively, the drawings illustrating the method of the present invention may omit some components and include only some components within a scope that does not harm the essence of the present invention.

[0317] In addition, the method of the present invention may be implemented by combining some or all of the contents included in each embodiment within a scope that does not harm the essence of the invention.

[0318] Various embodiments of the present disclosure have been described above. The foregoing description of the present disclosure is for illustrative purposes only, and the embodiments of the present disclosure are not limited to the disclosed embodiments. Those skilled in the art will appreciate that the present disclosure can be readily modified into other specific forms without altering the technical spirit or essential characteristics of the present disclosure. The scope of the present disclosure is indicated by the claims described below rather than the detailed description above, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present disclosure.

Claims

1. A method performed by a terminal of a communication system using a satellite network (non-terrestrial network), A step of receiving cell-specific slot offset information from a base station; A step of receiving terminal-specific slot offset information from the base station; A step of receiving downlink control information for scheduling downlink data from the base station; A step for determining a slot for transmitting HARQ-ACK (hybrid automatic repeat request - acknowledgement) information for the downlink data based on whether the downlink data is multicast data; A method characterized by comprising a step of transmitting the HARQ-ACK information in the slot.

2. In the first paragraph, if the downlink data is the multicast data, the slot is determined based on the cell-specific slot offset information, A method characterized in that, if the downlink data is not the multicast data, the slot is determined based on the cell-specific slot offset information and the terminal-specific slot offset information.

3. In paragraph 1, Further comprising a step of receiving group slot offset information from the base station, If the above downlink data is the multicast data, the slot is determined based on the cell-specific slot offset information and the group slot offset information, A method characterized in that, if the downlink data is not the multicast data, the slot is determined based on the cell-specific slot offset information and the terminal-specific slot offset information.

4. In paragraph 1, A method characterized in that whether the above downlink data is the above multicast data is determined based on the format of the above downlink control information.

5. In a method performed by a terminal of a communication system using a non-terrestrial network, A step of transmitting cell-specific slot offset information to a terminal; A step of transmitting terminal-specific slot offset information to the terminal; A step of transmitting downlink control information for scheduling downlink data to the terminal; Including a step of receiving HARQ-ACK (hybrid automatic repeat request - acknowledgement) information for the above downlink data in a slot, A method characterized in that the above slot is based on whether the downlink data is multicast data.

6. In the fourth paragraph, if the downlink data is the multicast data, the slot is based on the cell-specific slot offset information, A method characterized in that when the downlink data is not the multicast data, the slot is based on the cell-specific slot offset information and the terminal-specific slot offset information.

7. In paragraph 4, Further comprising a step of transmitting group slot offset information to the terminal; If the above downlink data is the above multicast data, the slot is based on the cell-specific slot offset information and the group slot offset information, A method characterized in that when the downlink data is not the multicast data, the slot is based on the cell-specific slot offset information and the terminal-specific slot offset information.

8. In paragraph 4, A method characterized in that whether the above downlink data is the above multicast data is related to the format of the above downlink control information.

9. In a method performed by a terminal of a communication system using a non-terrestrial network, Transmitter and receiver; and Receive cell-specific slot offset information from the base station, Receive terminal-specific slot offset information from the above base station, Receive downlink control information for scheduling downlink data from the above base station, Determine a slot for transmitting HARQ-ACK (hybrid automatic repeat request - acknowledgement) information for the downlink data based on whether the downlink data is multicast data, and A terminal characterized by including a control unit configured to transmit the HARQ-ACK information in the slot.

10. In paragraph 9, if the downlink data is the multicast data, the slot is determined based on the cell-specific slot offset information, A terminal, characterized in that when the downlink data is not the multicast data, the slot is determined based on the cell-specific slot offset information and the terminal-specific slot offset information.

11. In paragraph 9, The above control unit is further set to receive group slot offset information from the base station, If the above downlink data is the multicast data, the slot is determined based on the cell-specific slot offset information and the group slot offset information, A terminal, characterized in that when the downlink data is not the multicast data, the slot is determined based on the cell-specific slot offset information and the terminal-specific slot offset information.

12. In paragraph 9, A terminal characterized in that whether the above downlink data is the above multicast data is determined based on the format of the above downlink control information.

13. In a method performed by a terminal of a communication system using a non-terrestrial network, Transmitter and receiver; and Transmit cell-specific slot offset information to the terminal, Transmit terminal-specific slot offset information to the above terminal, Transmitting downlink control information for scheduling downlink data to the above terminal, and Including a control unit configured to receive HARQ-ACK (hybrid automatic repeat request - acknowledgement) information for the above downlink data in a slot, A base station, wherein the above slot is based on whether the downlink data is multicast data.

14. In the 13th paragraph, if the downlink data is the multicast data, the slot is based on the cell-specific slot offset information, A base station, characterized in that when the downlink data is not the multicast data, the slot is based on the cell-specific slot offset information and the terminal-specific slot offset information.

15. In paragraph 13, The above control unit is further set to transmit group slot offset information to the terminal, If the above downlink data is the above multicast data, the slot is based on the cell-specific slot offset information and the group slot offset information, A base station, characterized in that when the downlink data is not the multicast data, the slot is based on the cell-specific slot offset information and the terminal-specific slot offset information.

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