Method and apparatus for initial access in satellite communication system

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting a data transmission rate higher than that of a 4G communication system such as LTE. A terminal for performing communication with a satellite, according to one embodiment of the disclosure, can perform the steps of: receiving, from a satellite, configuration information related to initial access-related signals, the configuration information including a first PRACH resource associated with repeated transmission and reception of the initial access-related signals and a second PRACH resource associated with single transmission and reception of the initial access-related signals; selecting one from among the first PRACH resource and the second PRACH resource on the basis of whether an initial access-related signal is repeatedly transmitted and received; according to the selection of the first PRACH resource, using the first PRACH resource so as to perform repeated transmission and reception of the initial access-related signals with the satellite if a random access preamble is transmitted to the satellite; and, according to the selection of the second PRACH resource, using the second PRACH resource so as to perform single transmission and reception of the initial access-related signals with the satellite if the random access preamble is transmitted to the satellite.

Description

Method and device for initial connection 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 signals for initial connection in a satellite communication system, and a device capable of performing the method.

[0002] Looking back at the evolution of wireless communication over successive generations, technologies have primarily been developed for human-facing services such as voice, multimedia, and data. With the commercialization of 5G (5th-generation) communication systems, an explosive increase in connected devices is expected to be connected to communication networks. Examples of networked objects include vehicles, robots, drones, home appliances, displays, smart sensors installed in various infrastructures, construction equipment, and factory equipment. Mobile devices are also expected to evolve into diverse form factors, such as augmented reality glasses, virtual reality headsets, and holographic devices. In the 6th-generation (6G) era, efforts are being made to develop improved 6G communication systems to connect hundreds of billions of devices and objects and provide diverse services. For this reason, 6G communication systems are often referred to as "beyond 5G."

[0003] The 6G communication system, expected to be realized around 2030, will have a maximum transmission speed of terabytes per second (i.e., 1,000 gigabits per second) and a wireless latency of 100 microseconds (μsec). In other words, compared to 5G, the transmission speed in a 6G communication system will be 50 times faster, while the wireless latency will be reduced to one-tenth.

[0004] To achieve these high data rates and ultra-low latency, 6G communication systems are being considered for implementation in the terahertz band (e.g., from 95 gigahertz (GHz) to 3 terahertz (THz)). Compared to the millimeter wave (mmWave) band introduced in 5G, the terahertz band is expected to experience more severe path loss and atmospheric absorption, making it more crucial to ensure signal reach, or coverage, in this band. Key technologies to ensure coverage include radio frequency (RF) components, antennas, new waveforms that offer better coverage than OFDM (orthogonal frequency division multiplexing), beamforming, and multiple antenna transmission technologies such as massive multiple-input and multiple-output (MIMO), full-dimensional MIMO (FD-MIMO), array antennas, and large-scale antennas. In addition, new technologies such as metamaterial-based lenses and antennas, high-dimensional spatial multiplexing using orbital angular momentum (OAM), and reconfigurable intelligent surfaces (RIS) are being discussed to improve the coverage of terahertz band signals.

[0005] In addition, in order to improve frequency efficiency and system network, 6G communication systems are developing full duplex technology that utilizes the same frequency resources for uplink and downlink at the same time; network technology that integrates satellites and high-altitude platform stations (HAPS); network structure innovation technology that supports mobile base stations and enables optimization and automation of network operation; dynamic spectrum sharing technology through collision avoidance based on spectrum usage prediction; AI-based communication technology that utilizes artificial intelligence (AI) from the design stage and internalizes end-to-end AI support functions to realize system optimization; and next-generation distributed computing technology that realizes services with complexity that exceeds the limits of terminal computing capabilities by utilizing ultra-high-performance communication and computing resources (mobile edge computing (MEC), cloud, etc.). In addition, efforts are being made to further strengthen connectivity between devices, further optimize networks, promote softwareization of network entities, and increase the openness of wireless communications through the design of new protocols to be used in 6G communication systems, the implementation of hardware-based security environments, the development of mechanisms for the safe use of data, and the development of technologies for maintaining privacy.

[0006] Research and development of these 6G communication systems are expected to enable a new level of hyper-connected experience through the hyper-connectivity of 6G communication systems, which encompass not only connections between things but also connections between people and things. Specifically, 6G communication systems are expected to enable services such as truly immersive extended reality (Truly Immersive XR), high-fidelity mobile holograms, and digital replicas. Furthermore, services such as remote surgery, industrial automation, and emergency response, which are provided through enhanced security and reliability, will find application in diverse fields such as industry, healthcare, automotive, and home appliances.

[0007] The disclosed embodiment seeks to provide a device and method capable of effectively providing a service in a mobile communication system.

[0008] A method for a terminal to perform communication with a satellite in a wireless communication system according to one embodiment of the present disclosure may include: receiving configuration information regarding initial access related signals from a satellite, wherein the configuration information includes a first physical random access channel (PRACH) resource associated with repeated transmission and reception of the initial access related signals and a second PRACH resource associated with single transmission and reception of the initial access related signals; selecting one of the first PRACH resource and the second PRACH resource based on whether the initial access related signals are repeatedly transmitted and received; performing repeated transmission and reception of the initial access related signals with the satellite when a random access preamble is transmitted to the satellite using the first PRACH resource according to selection of the first PRACH resource; and performing single transmission and reception of the initial access related signals with the satellite when the random access preamble is transmitted to the satellite using the second PRACH resource according to selection of the second PRACH resource.

[0009] In a method for a terminal to perform communication with a satellite in a wireless communication system according to one embodiment of the present disclosure, the step of selecting one of the first PRACH resource and the second PRACH resource may select one of the first PRACH resource and the second PRACH resource using the reception signal strength of an SSB received from the satellite, the distance between the satellite and the terminal, or time period information set from the satellite.

[0010] In a method for a terminal to perform communication with a satellite in a wireless communication system according to one embodiment of the present disclosure, the configuration information regarding the initial access-related signals includes at least one of a reception signal strength threshold value, a distance threshold value, and the time period information, and when the reception signal strength of the received SSB is lower than the reception signal strength threshold value, the first PRACH resource is selected, and when the distance between the satellite and the terminal is further than the distance threshold value, the first PRACH resource is selected, and the time period information may indicate a time period during which each of the first PRACH resource and the second PRACH resource is selected.

[0011] In a method for a terminal to perform communication with a satellite in a wireless communication system according to one embodiment of the present disclosure, setting information regarding initial connection-related signals may include information indicating the number of times the initial connection-related signals are repeatedly transmitted and received.

[0012] In a method for a terminal to perform communication with a satellite in a wireless communication system according to one embodiment of the present disclosure, if the number of initial access-related signals included in the setting information regarding the initial access-related signals is plural, a step of selecting one of the plural numbers using at least one of a medium access control-control element (MAC CE) or downlink control information (DCI) received from the satellite may be further included.

[0013] A method for a terminal to perform communication with a satellite in a wireless communication system according to one embodiment of the present disclosure may further include a step of identifying whether to perform 2-step RA (random access) or 4-step RA for initial connection to the satellite based on setting information regarding the initial connection-related signals, distance between the terminal and the satellite, or preset time interval information.

[0014] A terminal for performing communication with a satellite in a wireless communication system according to one embodiment of the present disclosure comprises: a transceiver; And at least one processor connected to the transceiver, wherein the at least one processor: receives configuration information regarding initial access related signals from the satellite, the configuration information includes a first PRACH (physical random access channel) resource associated with repeated transmission and reception of the initial access related signals and a second PRACH resource associated with single transmission and reception of the initial access related signals, and selects one of the first PRACH resource and the second PRACH resource based on whether the initial access related signal is repeatedly transmitted and received, and when a random access preamble is transmitted to the satellite using the first PRACH resource according to selection of the first PRACH resource, performs repeated transmission and reception of the initial access related signals with the satellite, and when the random access preamble is transmitted to the satellite using the second PRACH resource according to selection of the second PRACH resource, performs single transmission and reception of the initial access related signals with the satellite.

[0015] A method for a satellite to perform communication with a terminal in a wireless communication system according to one embodiment of the present disclosure may include the steps of: transmitting configuration information regarding initial access related signals to the terminal, wherein the configuration information includes a first physical random access channel (PRACH) resource associated with repeated transmission and reception of the initial access related signals and a second PRACH resource associated with single transmission and reception of the initial access related signals; performing repeated transmission and reception of the initial access related signals with the terminal when a random access preamble is received from the terminal using the first PRACH resource as the first PRACH resource is selected by the terminal; and performing single transmission and reception of the initial access related signals with the terminal when the random access preamble is received from the terminal using the second PRACH resource as the second PRACH resource is selected by the terminal.

[0016] In a wireless communication system according to one embodiment of the present disclosure, a satellite for performing communication with a terminal comprises: a transceiver; and at least one processor connected to the transceiver, wherein the at least one processor: transmits configuration information regarding initial access related signals to the terminal, the configuration information including a first physical random access channel (PRACH) resource associated with repeated transmission and reception of the initial access related signals and a second PRACH resource associated with single transmission and reception of the initial access related signals, and when the first PRACH resource is selected by the terminal and a random access preamble is received from the terminal using the first PRACH resource, the satellite performs repeated transmission and reception of the initial access related signals with the terminal, and when the second PRACH resource is selected by the terminal and the random access preamble is received from the terminal using the second PRACH resource, the satellite performs single transmission and reception of the initial access related signals with the terminal.

[0017] The disclosed embodiment provides a device and method capable of effectively providing a service in a mobile communication system.

[0018] FIG. 1 is a diagram illustrating a basic structure of a time-frequency domain in a wireless communication system according to one embodiment of the present disclosure.

[0019] FIG. 2 is a diagram illustrating a frame, subframe, and slot structure in a wireless communication system according to one embodiment of the present disclosure.

[0020] FIG. 3 is a diagram illustrating an example of bandwidth portion settings in a wireless communication system according to one embodiment of the present disclosure.

[0021] FIG. 4 is a diagram illustrating an example of setting a control region of a downlink control channel in a wireless communication system according to one embodiment of the present disclosure.

[0022] FIG. 5 is a diagram illustrating the structure of a downlink control channel in a wireless communication system according to one embodiment of the present disclosure.

[0023] FIG. 6 is a diagram illustrating a case in which a terminal can have multiple PDCCH monitoring positions within a slot through Span in a wireless communication system according to one embodiment of the present disclosure.

[0024] FIG. 7 is a diagram illustrating an example of base station beam allocation according to TCI state settings in a wireless communication system according to one embodiment of the present disclosure.

[0025] FIG. 8 is a diagram illustrating an example of a TCI state allocation method for a PDCCH in a wireless communication system according to one embodiment of the present disclosure.

[0026] FIG. 9 is a diagram illustrating a TCI indication MAC CE signaling structure for PDCCH DMRS in a wireless communication system according to one embodiment of the present disclosure.

[0027] FIG. 10 is a diagram illustrating an example of a control resource set and a beam setting of a search space in a wireless communication system according to one embodiment of the present disclosure.

[0028] FIG. 11 is a diagram for explaining a method for a base station and a terminal to transmit and receive data in consideration of a downlink data channel and rate matching resources in a wireless communication system according to one embodiment of the present disclosure.

[0029] FIG. 12 is a diagram for explaining a method for selecting a set of control resources that can be received by a terminal in consideration of priority when receiving a downlink control channel in a wireless communication system according to one embodiment of the present disclosure.

[0030] FIG. 13 is a diagram illustrating an example of an aperiodic CSI reporting method according to one embodiment of the present disclosure.

[0031] FIG. 14 is a diagram illustrating an example of PUSCH repetition transmission type B in a wireless communication system according to one embodiment of the present disclosure.

[0032] FIG. 15 is a diagram illustrating a wireless protocol structure of a base station and a terminal in a single cell, carrier aggregation, and dual connectivity situation in a wireless communication system according to one embodiment of the present disclosure.

[0033] FIG. 16 is a diagram illustrating an example of antenna port configuration and resource allocation for cooperative communication in a wireless communication system according to an embodiment of the present disclosure.

[0034] FIG. 17 is a diagram illustrating an example of configuring downlink control information (DCI) for cooperative communication in a wireless communication system according to an embodiment of the present disclosure.

[0035] Figure 18 illustrates a procedure for a base station to control the transmission power of a terminal in a cellular system.

[0036] FIG. 19 is a diagram illustrating a process for generating a Type-1 (semi-static) HARQ-ACK codebook by a terminal according to one embodiment of the present disclosure.

[0037] FIG. 20 is a diagram illustrating a process for generating a Type-2 (dynamic) HARQ-ACK codebook by a terminal according to one embodiment of the present disclosure.

[0038] FIG. 21 is a diagram illustrating a procedure for transmitting and receiving data between a terminal and a base station to perform initial connection according to one embodiment.

[0039] FIG. 22 is a diagram illustrating 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.

[0040] FIG. 23 is a diagram illustrating a procedure in which a terminal and a base station repeatedly transmit and receive signals to perform an initial connection according to one embodiment.

[0041] FIG. 24 is a flowchart illustrating a process for repeated transmission and reception when a terminal initially connects to a satellite network according to one embodiment of the present disclosure.

[0042] FIG. 25 is a block diagram illustrating the internal structure of a satellite according to an embodiment of the present disclosure.

[0043] FIG. 26 is a diagram illustrating the structure of a terminal in a wireless communication system according to an embodiment of the present disclosure.

[0044] FIG. 27 is a diagram illustrating the structure of a base station in a wireless communication system according to an embodiment of the present disclosure.

[0045] A method for a terminal to perform communication with a satellite in a wireless communication system according to one embodiment of the present disclosure may include: receiving configuration information regarding initial access related signals from a satellite, wherein the configuration information includes a first physical random access channel (PRACH) resource associated with repeated transmission and reception of the initial access related signals and a second PRACH resource associated with single transmission and reception of the initial access related signals; selecting one of the first PRACH resource and the second PRACH resource based on whether the initial access related signals are repeatedly transmitted and received; performing repeated transmission and reception of the initial access related signals with the satellite when a random access preamble is transmitted to the satellite using the first PRACH resource according to selection of the first PRACH resource; and performing single transmission and reception of the initial access related signals with the satellite when the random access preamble is transmitted to the satellite using the second PRACH resource according to selection of the second PRACH resource.

[0046] In a method for a terminal to perform communication with a satellite in a wireless communication system according to one embodiment of the present disclosure, the step of selecting one of the first PRACH resource and the second PRACH resource may select one of the first PRACH resource and the second PRACH resource using the reception signal strength of an SSB received from the satellite, the distance between the satellite and the terminal, or time period information set from the satellite.

[0047] In a method for a terminal to perform communication with a satellite in a wireless communication system according to one embodiment of the present disclosure, the configuration information regarding the initial access-related signals includes at least one of a reception signal strength threshold value, a distance threshold value, and the time period information, and when the reception signal strength of the received SSB is lower than the reception signal strength threshold value, the first PRACH resource is selected, and when the distance between the satellite and the terminal is further than the distance threshold value, the first PRACH resource is selected, and the time period information may indicate a time period during which each of the first PRACH resource and the second PRACH resource is selected.

[0048] In a method for a terminal to perform communication with a satellite in a wireless communication system according to one embodiment of the present disclosure, setting information regarding initial connection-related signals may include information indicating the number of times the initial connection-related signals are repeatedly transmitted and received.

[0049] In a method for a terminal to perform communication with a satellite in a wireless communication system according to one embodiment of the present disclosure, if the number of initial access-related signals included in the setting information regarding the initial access-related signals is plural, a step of selecting one of the plural numbers using at least one of a medium access control-control element (MAC CE) or downlink control information (DCI) received from the satellite may be further included.

[0050] A method for a terminal to perform communication with a satellite in a wireless communication system according to one embodiment of the present disclosure may further include a step of identifying whether to perform 2-step RA (random access) or 4-step RA for initial connection to the satellite based on setting information regarding the initial connection-related signals, distance between the terminal and the satellite, or preset time interval information.

[0051] A terminal for performing communication with a satellite in a wireless communication system according to one embodiment of the present disclosure comprises: a transceiver; And at least one processor connected to the transceiver, wherein the at least one processor: receives configuration information regarding initial access related signals from the satellite, the configuration information includes a first PRACH (physical random access channel) resource associated with repeated transmission and reception of the initial access related signals and a second PRACH resource associated with single transmission and reception of the initial access related signals, and selects one of the first PRACH resource and the second PRACH resource based on whether the initial access related signal is repeatedly transmitted and received, and when a random access preamble is transmitted to the satellite using the first PRACH resource according to selection of the first PRACH resource, performs repeated transmission and reception of the initial access related signals with the satellite, and when the random access preamble is transmitted to the satellite using the second PRACH resource according to selection of the second PRACH resource, performs single transmission and reception of the initial access related signals with the satellite.

[0052] A method for a satellite to perform communication with a terminal in a wireless communication system according to one embodiment of the present disclosure may include the steps of: transmitting configuration information regarding initial access related signals to the terminal, wherein the configuration information includes a first physical random access channel (PRACH) resource associated with repeated transmission and reception of the initial access related signals and a second PRACH resource associated with single transmission and reception of the initial access related signals; performing repeated transmission and reception of the initial access related signals with the terminal when a random access preamble is received from the terminal using the first PRACH resource as the first PRACH resource is selected by the terminal; and performing single transmission and reception of the initial access related signals with the terminal when the random access preamble is received from the terminal using the second PRACH resource as the second PRACH resource is selected by the terminal.

[0053] In a wireless communication system according to one embodiment of the present disclosure, a satellite for performing communication with a terminal comprises: a transceiver; and at least one processor connected to the transceiver, wherein the at least one processor: transmits configuration information regarding initial access related signals to the terminal, the configuration information including a first physical random access channel (PRACH) resource associated with repeated transmission and reception of the initial access related signals and a second PRACH resource associated with single transmission and reception of the initial access related signals, and when the first PRACH resource is selected by the terminal and a random access preamble is received from the terminal using the first PRACH resource, the satellite performs repeated transmission and reception of the initial access related signals with the terminal, and when the second PRACH resource is selected by the terminal and the random access preamble is received from the terminal using the second PRACH resource, the satellite performs single transmission and reception of the initial access related signals with the terminal.

[0054] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the attached drawings.

[0055] 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 avoid obscuring the gist of the present disclosure by omitting unnecessary explanations and to convey the gist more clearly.

[0056] 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.

[0057] 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.

[0058] Hereinafter, the base station is an entity that performs resource allocation of the 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. The terminal may include a UE (User Equipment), an MS (Mobile Station), a cellular phone, a smartphone, a computer, or a multimedia system capable of performing a communication function. In the present disclosure, downlink (DL) refers to a wireless transmission path of a signal transmitted from a base station to a terminal, and uplink (UL) refers to a wireless transmission path of a signal transmitted from a terminal to a base station. In addition, although the LTE or LTE-A system may be described below as an example, the embodiments of the present disclosure may also be applied to other communication systems having a similar technical background or channel type. For example, the 5th generation mobile communication technology (5G, new radio, NR) developed after LTE-A may be included here, and the 5G below may also be a concept that includes existing LTE, LTE-A, and other similar services. In addition, the present disclosure may be applied to other communication systems through 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.

[0059] 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).

[0060] 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.

[0061] Here, the term '~ part' used in this embodiment means software or hardware components such as FPGA (Field Programmable Gate Array) or ASIC (Application Specific Integrated Circuit), and the '~ part' performs certain roles. However, the '~ part' is not limited to software or hardware. The '~ part' may be configured to be on an addressable storage medium or may be configured to play one or more processors. Therefore, as an example, the '~ part' includes components such as software components, object-oriented software components, class components, and task components, processes, functions, properties, 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 '~ parts' may be combined into a smaller number of components and '~ parts' or further separated into additional components and '~ parts'. 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.

[0062] 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.

[0063] As a representative example of the above broadband wireless communication system, the LTE system adopts the OFDM (Orthogonal Frequency Division Multiplexing) method in the downlink (DL) and the SC-FDMA (Single Carrier Frequency Division Multiple Access) method in the uplink (UL). The uplink refers to a wireless link in which a terminal (User Equipment (UE) or Mobile Station (MS)) transmits data or control signals to a base station (eNode B or base station (BS)), and the downlink refers to a wireless link in which a base station transmits data or control signals to a terminal. The above multiple access method can distinguish the data or control information of each user by allocating and operating 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.

[0064] As a future communications 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 Reliability Low Latency Communication (URLLC).

[0065] 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 the perspective of 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 transmission bandwidth of 20 MHz in the 2 GHz band, 5G communication systems can meet the data transmission rates required by 5G communication systems by using a wider frequency bandwidth than 20 MHz in the 3-6 GHz or higher 6 GHz band.

[0066] 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 IoT, mMTC requires supporting large-scale terminal connections within a cell, improved terminal coverage, enhanced battery life, and reduced terminal costs. The IoT requires the ability to support a large number of terminals (e.g., 1,000,000 terminals / km2) within a cell, as it provides communication capabilities through the attachment of various sensors and devices. Furthermore, due to the nature of the service, terminals supporting mMTC are likely to be located in shadow areas, such as basements, beyond cell coverage. This may require broader coverage compared to other services provided by 5G communication systems. Terminals supporting mMTC must be inexpensive, and since frequent battery replacement is unlikely, they may require extremely long battery lifespans, such as 10 to 15 years.

[0067] 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 (UAVs), 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, must have 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.

[0068] The three 5G services—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, 5G is not limited to the three services described above.

[0069] [NR time-frequency resources]

[0070] Below, the frame structure of the 5G system is described in more detail with reference to drawings.

[0071] Figure 1 is a diagram illustrating 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.

[0072] The horizontal axis of Fig. 1 represents the time domain, and the vertical axis represents the frequency domain. One subframe (110) may be composed of multiple symbols. The basic unit of resources in the time and frequency domains is a resource element (RE, 101), which may be defined as 1 OFDM (Orthogonal Frequency Division Multiplexing) symbol (102) in the time axis and 1 subcarrier (103) in the frequency axis. In the frequency domain (For example, 12) consecutive REs can form one resource block (RB, 104).

[0073] FIG. 2 is a diagram illustrating a frame, subframe, and slot structure in a wireless communication system according to one embodiment of the present disclosure.

[0074] 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 10ms. One subframe (201) can be defined as 1ms, and therefore one frame (200) can be composed of a total of 10 subframes (201). One slot (202 or 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 an 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 1 slot (202), and when μ = 1 (205), 1 subframe (201) may be composed of 2 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.

[0075] [Table 1]

[0076]

[0077] [Bandwidth Part (BWP)]

[0078] Next, the bandwidth part (BWP) setting in the 5G communication system will be explained in detail with reference to the drawing.

[0079] FIG. 3 is a diagram illustrating an example of bandwidth portion settings in a wireless communication system according to one embodiment of the present disclosure.

[0080] Figure 3 shows 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 following information for each bandwidth portion.

[0081] [Table 2]

[0082]

[0083] Of course, the information set for each bandwidth portion is not limited to the above examples, and in addition to the above-mentioned setting information, various parameters related to the bandwidth portion may be set for the terminal. The above-mentioned information may be transmitted from the base station to the terminal via upper layer signaling, for example, RRC (Radio Resource Control) signaling. At least one of the configured one or more 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 DCI (Downlink Control Information).

[0084] According to some embodiments, a terminal before RRC (Radio Resource Control) 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, through the MIB 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. The control region and search space configured by the MIB may each be regarded as identifier (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 occasion for control region #0, i.e., configuration information for search space #0, through the MIB. The terminal may consider the frequency range set as control area #0 obtained from the MIB as the initial bandwidth portion for initial connection. At this time, the identifier (ID) of the initial bandwidth portion may be considered as 0.

[0085] The settings for the bandwidth supported by the above 5G can be used for various purposes.

[0086] 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.

[0087] 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.

[0088] 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, for example, 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, for example, 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.

[0089] In the method for setting the bandwidth part, terminals before RRC connection (Connected) can receive setting information for the initial bandwidth part through the MIB (Master Information Block) in the initial access stage. More specifically, the terminal can set a control region (Control Resource Set, CORESET) for a downlink control channel on which DCI (Downlink Control Information) for scheduling a SIB (System Information Block) can be transmitted from the MIB of the PBCH (Physical Broadcast Channel). The bandwidth of the control region set by the MIB can be regarded as the initial bandwidth part, and the terminal can receive the PDSCH (Physical Downlink Shared Channel) on which the SIB is transmitted through the set initial bandwidth part. In addition to the purpose of receiving the SIB, the initial bandwidth part can also be utilized for other system information (Other System Information, OSI), paging, and random access.

[0090] [Bandwidth Part (BWP) Change]

[0091] When one or more bandwidth parts are set for a terminal, the base station can instruct the terminal to change (or switch, transition) the bandwidth part using the bandwidth part indicator field in the DCI. For example, in FIG. 3, when the currently activated bandwidth part of the terminal is bandwidth part #1 (301), the base station can instruct the terminal to bandwidth part #2 (302) using the bandwidth part indicator in the DCI, and the terminal can perform a bandwidth part change to bandwidth part #2 (302) indicated by the bandwidth part indicator in the received DCI.

[0092] As described above, since DCI-based bandwidth part change can be indicated by DCI scheduling PDSCH or PUSCH, when a terminal receives a bandwidth part change request, it must be able to receive or transmit PDSCH or PUSCH scheduled by the corresponding DCI without difficulty in the changed bandwidth part. To this end, the standard stipulates the delay time (T) required when changing the bandwidth part. BWP ) and can be defined as follows, for example:

[0093] [Table 3]

[0094]

[0095] The bandwidth-partial change delay time requirement supports Type 1 or Type 2 depending on the terminal's capability. The terminal can report the supported bandwidth-partial delay time type to the base station.

[0096] According to the requirement for bandwidth part change delay time mentioned above, when the terminal receives DCI including bandwidth part change indicator in slot n, the terminal changes to the new bandwidth part indicated by the bandwidth part change indicator in slot n+T. BWP The completion can be done at a later time, and transmission and reception for the data channel scheduled by the DCI can be performed in the new bandwidth portion that has been changed. When the base station wants to schedule a data channel in the new bandwidth portion, the terminal's bandwidth portion change delay time (T BWP ), time domain resource allocation for the data channel can be determined. That is, when the base station schedules the data channel with a new bandwidth portion, the data channel can be scheduled after the bandwidth portion change delay time in the method of determining the time domain resource allocation for the data channel. Accordingly, the terminal can determine whether the DCI instructing the bandwidth portion change is after the bandwidth portion change delay time (T BWP) may not be expected to indicate a slot offset (K0 or K2) value smaller than that.

[0097] If the terminal receives DCI (e.g., DCI format 1_1 or 0_1) indicating a bandwidth change, the terminal may not perform any transmission or reception during the time period from the third symbol of the slot in which the PDCCH including the DCI is received to the start point of the slot indicated by the slot offset (K0 or K2) value indicated by the time domain resource allocation indicator field in the DCI. For example, if the terminal receives DCI indicating a bandwidth change in slot n and the slot offset value indicated by the DCI is K, the terminal may not perform any transmission or reception from the third symbol of slot n to the symbol before slot n+K (i.e., the last symbol of slot n+K-1).

[0098] [SS / PBCH block]

[0099] Next, we will explain the SS (Synchronization Signal) / PBCH block in 5G.

[0100] 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.

[0101] - PSS: A signal that serves as a reference for downlink time / frequency synchronization and provides some information about the cell ID.

[0102] - SSS: It serves as a reference for downlink time / frequency synchronization and provides the remaining cell ID information not provided by PSS. Additionally, it can serve as a reference signal for PBCH demodulation.

[0103] - PBCH: Provides essential system information required for transmission and reception of data and control channels of 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.

[0104] - 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.

[0105] The terminal can detect PSS and SSS in the initial access stage, and decode PBCH. The terminal can obtain MIB from PBCH, and can set control region (Control Resource Set; CORESET) #0 (which may correspond to a control region with a control region index of 0) therefrom. The terminal can monitor control region #0, assuming that the selected SS / PBCH block and the DMRS (Demodulation Reference Signal) transmitted in control region #0 are QCL (Quasi Co Location). 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 on the SS / PBCH block index selected by the terminal. The base station can know that the terminal has selected a block among each SS / PBCH block and monitors the control region #0 associated with it.

[0106] [PDCCH: DCI related]

[0107] Next, we will specifically explain downlink control information (DCI) in the 5G system.

[0108] 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 DCI format for fallback and a DCI format for non-fallback 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.

[0109] DCI can be transmitted through 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 on 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.

[0110] 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).

[0111] 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 following information.

[0112] [Table 4]

[0113]

[0114] 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 following information.

[0115] [Table 5]

[0116]

[0117]

[0118] 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 following information.

[0119] [Table 6]

[0120]

[0121] 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 following information.

[0122] [Table 7]

[0123]

[0124] [PDCCH: CORESET, REG, CCE, Search Space]

[0125] Below, the downlink control channel in a 5G communication system will be described in more detail with reference to drawings.

[0126] FIG. 4 is a diagram illustrating an example of a control region (Control Resource Set, CORESET) in which a downlink control channel is transmitted in a 5G wireless communication system. FIG. 4 illustrates an example in which two control regions (Control Region #1 (401), Control Region #2 (402)) are set within a UE bandwidth part (410) in the frequency axis and one slot (420) in the time axis. The control regions (401, 402) may be set to specific frequency resources (403) within the entire UE bandwidth part (410) in the frequency axis. The control regions (401, 402) may be set to one or more OFDM symbols in the time axis, which may be defined by the control region length (Control Resource Set Duration, 404). Referring to the illustrated example of FIG. 4, control area #1 (401) is set to a control area length of 2 symbols, and control area #2 (402) is set to a control area length of 1 symbol.

[0127] In the aforementioned 5G, the control region can be established by the base station to the terminal via higher-layer signaling (e.g., system information, Master Information Block (MIB), Radio Resource Control (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, the following information may be provided to establish the control region.

[0128] [Table 8]

[0129]

[0130] In Table 8, the tci-StatesPDCCH (simply named TCI (Transmission Configuration Indication) state) configuration information may include information on one or more SS (Synchronization Signal) / PBCH (Physical Broadcast Channel) 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.

[0131] FIG. 5 is a diagram showing an example of a basic unit of time and frequency resources that constitute a downlink control channel that can be used in 5G. According to FIG. 5, the basic unit of time and frequency resources that constitute a control channel can be referred to as a REG (Resource Element Group, 503), and a REG (503) can be defined as 1 OFDM symbol (501) on the time axis and 1 PRB (Physical Resource Block, 502) on the frequency axis, i.e., 12 subcarriers. A base station can concatenate REGs (503) to constitute a downlink control channel allocation unit.

[0132] As illustrated in FIG. 5, if the basic unit to which a downlink control channel is allocated in 5G is called a CCE (Control Channel Element, 504), 1 CCE (504) can be composed of multiple REGs (503). Taking the REG (503) illustrated in FIG. 5 as an example, the REG (503) can be composed of 12 REs, and if 1 CCE (504) is composed of 6 REGs (503), 1 CCE (504) can be composed of 72 REs. When a downlink control region is set, the region can be composed of multiple CCEs (504), and a specific downlink control channel can be mapped to one or multiple CCEs (504) and transmitted according to the aggregation level (AL) within the control region. CCEs (504) within the control area are distinguished by numbers, and the numbers of the CCEs (504) can be assigned according to a logical mapping method.

[0133] The basic unit of the downlink control channel illustrated in FIG. 5, that is, the REG (503), may include both the REs to which the DCI is mapped and the areas to which the DMRS (505), which is a reference signal for decoding the REs, is mapped. As shown in FIG. 5, three DMRSs (505) may be transmitted within one REG (503). The number of CCEs required to transmit the PDCCH may be 1, 2, 4, 8, or 16 depending on the aggregation level (AL), 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 (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.

[0134] 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.

[0135] In 5G, parameters for the search space for PDCCH can be configured from the base station to the terminal via higher layer signaling (e.g., SIB, MIB, RRC signaling). For example, the base station can configure the number of PDCCH candidates at each aggregation level L, the monitoring period for the search space, the monitoring occasion for each symbol within the 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 following information can be configured for the terminal.

[0136] [Table 9]

[0137]

[0138] 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.

[0139] 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.

[0140] 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.

[0141] - 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

[0142] - DCI format 2_0 with CRC scrambled by SFI-RNTI

[0143] - DCI format 2_1 with CRC scrambled by INT-RNTI

[0144] - DCI format 2_2 with CRC scrambled by TPC-PUSCH-RNTI, TPC-PUCCH-RNTI

[0145] - DCI format 2_3 with CRC scrambled by TPC-SRS-RNTI

[0146] 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.

[0147] - DCI format 0_0 / 1_0 with CRC scrambled by C-RNTI, CS-RNTI, TC-RNTI

[0148] - DCI format 1_0 / 1_1 with CRC scrambled by C-RNTI, CS-RNTI, TC-RNTI

[0149] The RNTIs specified may follow the definitions and uses below.

[0150] C-RNTI (Cell RNTI): For terminal-specific PDSCH scheduling purposes

[0151] TC-RNTI (Temporary Cell RNTI): For terminal-specific PDSCH scheduling purposes

[0152] CS-RNTI (Configured Scheduling RNTI): Used for terminal-specific PDSCH scheduling that is set semi-statically.

[0153] RA-RNTI (Random Access RNTI): Used for PDSCH scheduling in the random access phase.

[0154] P-RNTI (Paging RNTI): Used for scheduling PDSCH where paging is transmitted.

[0155] SI-RNTI (System Information RNTI): Used for scheduling PDSCH where system information is transmitted.

[0156] INT-RNTI (Interruption RNTI): Used to indicate whether PDSCH is punctured.

[0157] TPC-PUSCH-RNTI (Transmit Power Control for PUSCH RNTI): Used to indicate power control commands for PUSCH.

[0158] TPC-PUCCH-RNTI (Transmit Power Control for PUCCH RNTI): Used to indicate power control commands for PUCCH.

[0159] TPC-SRS-RNTI (Transmit Power Control for SRS RNTI): Used to indicate power control commands for SRS.

[0160] The aforementioned specified DCI formats may follow the definitions below.

[0161] [Table 10]

[0162]

[0163] In 5G, the search space of aggregation level L in the control region p and search space set s can be expressed as in the following mathematical expression 1.

[0164] [Mathematical Formula 1]

[0165]

[0166] - : Integration level

[0167] - : Carrier Index

[0168] - : Total number of CCEs existing within the control region p

[0169] - : slot index

[0170] - : Number of PDCCH candidates for aggregation level L

[0171] - : PDCCH candidate index of aggregation level L

[0172] -

[0173] - , , , , ,

[0174] - : Terminal identifier

[0175] The value can be 0 for a common search space.

[0176] 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.

[0177] In 5G, 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.

[0178] [PDCCH: span]

[0179] A terminal can perform terminal capability reporting for each subcarrier interval when it has multiple PDCCH monitoring positions within a slot, and at this time, the concept of Span can be used. A Span refers to consecutive symbols within a slot in which the terminal can monitor a PDCCH, and each PDCCH monitoring position is within one Span. A Span can be expressed as (X, Y), where x refers to the minimum number of symbols that must be spaced between the first symbols of two consecutive Spans, and Y refers to the number of consecutive symbols in which the PDCCH can be monitored within one Span. In this case, the terminal can monitor the PDCCH in the section from the first symbol of the Span to within Y symbols within the Span.

[0180] FIG. 6 is a diagram illustrating a case in which a terminal in a wireless communication system can have multiple PDCCH monitoring positions within a slot, using Span. Span can be (X, Y) = (7, 4), (4, 3), (2, 2), and each of the three cases is represented by (6-00), (6-05), and (6-10) in FIG. 6. For example, (6-00) represents a case in which there are two Spans, which can be represented by (7, 4), within a slot. The interval between the first symbols of the two Spans is represented as X = 7, and PDCCH monitoring positions can exist within a total of Y = 3 symbols from the first symbol of each Span, and it is shown that search spaces 1 and 2 each exist within Y = 3 symbols. As another example, (6-05) represents a case where there are a total of three spans within a slot that can be expressed as (4,3), and the gap between the second and third spans is shown to be X'=5 symbols, which is greater than X=4.

[0181] [PDCCH: Terminal Capability Report]

[0182] The slot locations where the above-described common search space and terminal-specific search space are located are indicated by the monitoringSlotPeriodicityAndOffset parameter in Table 9, and the symbol locations within the slot are indicated as a bitmap through the monitoringSymbolsWithinSlot parameter in Table 9. Meanwhile, the symbol locations within the slot where the terminal can monitor the search space can be reported to the base station through the following terminal capabilities (UE capabilities).

[0183] - Terminal Capability 1 (hereinafter referred to as FG 3-1). This terminal capability refers to the capability to monitor a monitoring occasion (MO) for a Type 1 and Type 3 common search space or a terminal-specific search space when the MO location is located within the first three symbols of the slot, as shown in Table 11 below. This terminal capability is a mandatory capability that all terminals supporting NR must support, and whether or not they support this capability is not explicitly reported to the base station.

[0184] [Table 11]

[0185]

[0186] - Terminal Capability 2 (hereinafter referred to as FG 3-2). This terminal capability refers to the capability to monitor a common search space or a terminal-specific search space, regardless of the starting symbol position of a monitoring occasion (MO), if one exists within a slot, as shown in Table 12 below. This terminal capability is optional, and whether or not the terminal supports this capability is explicitly reported to the base station.

[0187] [Table 12]

[0188]

[0189] - Terminal capability 3 (hereinafter referred to as FG 3-5, 3-5a, 3-5b). This terminal capability indicates the pattern of MOs that the terminal can monitor when there are multiple monitoring positions (MOs: monitoring occasions) for a common search space or a terminal-specific search space within a slot, as shown in Table 13 below. The above-described pattern is composed of the start symbol interval X between different MOs and the maximum symbol length Y for an MO. The combination of (X,Y) supported by the terminal can be one or more of {(2,2), (4,3), (7,3)}. This terminal capability can be selectively supported by the terminal (optional), and whether this capability is supported and the above-described combination of (X,Y) are explicitly reported to the base station.

[0190] [Table 13]

[0191]

[0192]

[0193] The terminal may report to the base station whether it supports the aforementioned terminal capabilities 2 and / or 3 and related parameters. Based on the reported terminal capabilities, the base station may perform time-domain resource allocation for the common search space and terminal-specific search space. When allocating these resources, the base station may ensure that the MO is not positioned in a location that the terminal cannot monitor.

[0194] [QCL, TCI state]

[0195] In a wireless communication system, one or more different antenna ports (or one or more channels, signals, and combinations thereof, but for convenience, they will be referred to as different antenna ports in the following description of the present disclosure) can be associated with each other by a QCL (Quasi co-location) setting as shown in [Table 14] below. The TCI state is to notify the QCL relationship between the PDCCH (or PDCCH DMRS) and other RSs or channels. When a reference antenna port A (reference RS #A) and another target antenna port B (target RS #B) are QCLed with each other, it means that the terminal is allowed to apply some or all of the large-scale channel parameters estimated at the antenna port A to the channel measurement from the antenna port B. QCL may need to relate different parameters depending on the situation, such as 1) time tracking affected by average delay and delay spread, 2) frequency tracking affected by Doppler shift and Doppler spread, 3) radio resource management (RRM) affected by average gain, and 4) beam management (BM) affected by spatial parameters. Accordingly, NR supports four types of QCL relationships, as shown in Table 14 below.

[0196] [Table 14]

[0197]

[0198] The above spatial RX parameter may collectively refer to some or all of various parameters, such as Angle of arrival (AoA), Power Angular Spectrum (PAS) of AoA, Angle of departure (AoD), PAS of AoD, transmit / receive channel correlation, transmit / receive beamforming, and spatial channel correlation.

[0199] The above QCL relationship can be set to the terminal through the RRC parameters TCI-State and QCL-Info as shown in Table 15 below. Referring to Table 15, the base station can set one or more TCI states to the terminal and inform the RS referencing the ID of the TCI state, i.e., up to two QCL relationships (qcl-Type1, qcl-Type2) for the target RS. At this time, each QCL information (QCL-Info) included in the above TCI state includes the serving cell index and BWP index of the reference RS indicated by the corresponding QCL information, the type and ID of the reference RS, and the QCL type as shown in Table 14 above.

[0200] [Table 15]

[0201]

[0202] FIG. 7 is a diagram illustrating an example of base station beam allocation according to TCI state settings. Referring to FIG. 7, the base station can transmit information on N different beams to the terminal through N different TCI states. For example, in case of N=3 as shown in FIG. 7, the base station can notify that antenna ports referencing different TCI states 700, 705, or 710 have different spatial Rx parameters, i.e., are associated with different beams, by setting the qcl-Type2 parameter included in three TCI states (700, 705, 710) to be associated with CSI-RS or SSB corresponding to different beams and to QCL type D.

[0203] Tables 16 to 20 below show valid TCI state settings according to target antenna port type.

[0204] Table 16 shows valid TCI state settings when the target antenna port is a CSI-RS for tracking (TRS). The TRS refers to an NZP CSI-RS with no repetition parameter set and trs-Info set to true among CSI-RSs. Setting 3 in Table 16 can be used for aperiodic TRS.

[0205] [Table 16] Valid TCI state settings when the target antenna port is CSI-RS for tracking (TRS)

[0206]

[0207] Table 17 shows valid TCI state settings when the target antenna port is a CSI-RS for CSI. The CSI-RS for CSI refers to an NZP CSI-RS in which a parameter indicating repetition (e.g., repetition parameter) among CSI-RSs is not set and trs-Info is not set to true.

[0208] [Table 17] Valid TCI state settings when the target antenna port is CSI-RS for CSI

[0209]

[0210] Table 18 shows the valid TCI state settings when the target antenna port is CSI-RS for beam management (BM, synonymous with CSI-RS for L1 RSRP reporting). The CSI-RS for BM refers to an NZP CSI-RS in which the repetition parameter is set to On or Off among CSI-RSs and trs-Info is not set to true.

[0211] [Table 18] Valid TCI state settings when the target antenna port is CSI-RS for BM (for L1 RSRP reporting)

[0212]

[0213] Table 19 shows the valid TCI state settings when the target antenna port is PDCCH DMRS.

[0214] [Table 19] Valid TCI state settings when the target antenna port is PDCCH DMRS

[0215]

[0216] Table 20 shows the valid TCI state settings when the target antenna port is PDSCH DMRS.

[0217] [Table 20] Valid TCI state settings when the target antenna port is PDSCH DMRS

[0218]

[0219] A representative QCL configuration method according to Tables 16 to 20 above is to operate by setting the target antenna port and reference antenna port for each step as "SSB" -> "TRS" -> "CSI-RS for CSI, or CSI-RS for BM, or PDCCH DMRS, or PDSCH DMRS." Through this, it is possible to link statistical characteristics that can be measured from SSB and TRS to each antenna port to assist the terminal's reception operation.

[0220] [PDCCH: TCI state related]

[0221] Specifically, the TCI state combinations applicable to the PDCCH DMRS antenna port are as shown in Table 21 below. The fourth row in Table 21 is the combination assumed by the terminal before RRC configuration, and configuration after RRC is not possible.

[0222] [Table 21]

[0223]

[0224] NR supports a hierarchical signaling method as illustrated in FIG. 8 for dynamic allocation of PDCCH beams. Referring to FIG. 8, a base station can set N TCI states (805, 810, 815, ... ..., 820) to a terminal through RRC signaling (800), and can set some of them as TCI states for CORESET (825). Thereafter, the base station can indicate one of the TCI states (830, 835, 840) for CORESET to the terminal through MAC CE signaling (845). Thereafter, the terminal receives the PDCCH based on beam information included in the TCI state indicated by the MAC CE signaling.

[0225] FIG. 9 is a diagram illustrating a TCI indication MAC CE signaling structure for the PDCCH DMRS. Referring to FIG. 9, the TCI indication MAC CE signaling for the PDCCH DMRS is composed of 2 bytes (16 bits, Oct 1 (900), Oct 2 (905)) and may include a 5-bit serving cell ID (915), a 4-bit CORESET ID (920), and a 7-bit TCI state ID (925).

[0226] FIG. 10 is a diagram illustrating an example of beam configuration of a control resource set (CORESET) and a search space according to the above description. Referring to FIG. 10, a base station can indicate one of the TCI state lists included in the CORESET (1000) configuration through MAC CE signaling (1005). Thereafter, until another TCI state is indicated to the corresponding CORESET through another MAC CE signaling, the terminal considers that the same QCL information (beam #1, 1005) is applied to all one or more search spaces (1010, 1015, 1020) connected to the CORESET. The above-described PDCCH beam allocation method has a problem in that it is difficult to indicate a beam change faster than the MAC CE signaling delay, and also has a disadvantage in that the same beam is applied to all CORESETs regardless of the search space characteristics, which makes flexible PDCCH beam operation difficult. The embodiments of the present disclosure below provide a more flexible PDCCH beam configuration and operation method. In explaining embodiments of the present disclosure below, several distinct examples are provided for convenience of explanation, but these are not mutually exclusive and can be applied in appropriate combination depending on the situation.

[0227] A base station can set one or more TCI states for a specific control region to a terminal, and can activate one of the set TCI states through a MAC CE activation command. For example, if {TCI state#0, TCI state#1, TCI state#2} are set as TCI states in control region #1, the base station can transmit a command to the terminal to activate TCI state#0 for control region #1 through MAC CE. Based on the activation command for the TCI state received through MAC CE, the terminal can correctly receive DMRS of the corresponding control region based on QCL information in the activated TCI state.

[0228] For a control region (control region #0) with an index set to 0, if the terminal has not received a MAC CE activation command for the TCI state of control region #0, the terminal can assume that it has QCL with the SS / PBCH block identified during the initial access process or the non-contention-based random access process that is not triggered by a PDCCH command for the DMRS transmitted in control region #0.

[0229] For a control region (control region #X) whose index is set to a value other than 0, if the terminal has not set a TCI state for the control region #X, or has set one or more TCI states but has not received a MAC CE activation command to activate one of them, the terminal may assume that the DMRS transmitted in the control region #X is QCL with the SS / PBCH block identified during the initial access process.

[0230] [PDCCH: QCL prioritization rule related]

[0231] Below, the QCL priority determination operation for PDCCH is described in detail.

[0232] When a terminal operates in a single cell or with carrier aggregation within a band, and multiple control resource sets existing within an activated bandwidth portion of a single or multiple cells have the same or different QCL-TypeD characteristics and overlap in time during a specific PDCCH monitoring interval, the terminal may select a specific control resource set according to a QCL priority determination operation and monitor control resource sets having the same QCL-TypeD characteristics as the selected control resource set. That is, when multiple control resource sets overlap in time, the terminal can receive only one QCL-TypeD characteristic. In this case, the criteria for determining the QCL priority may be as follows.

[0233] - Criteria 1. The control resource set associated with the common search section of the lowest index within the cell corresponding to the lowest index among the cells containing the common search section.

[0234] - Criteria 2. The control resource set associated with the terminal-specific search section with the lowest index within the cell corresponding to the lowest index among the cells containing the terminal-specific search section.

[0235] As described above, if the above criteria are not met, the following criteria are applied. For example, if control resource sets overlap in time in a specific PDCCH monitoring interval, and if all control resource sets are not connected to a common search interval but to a terminal-specific search interval, i.e., if criterion 1 is not met, the terminal may skip applying criterion 1 and apply criterion 2.

[0236] When a terminal selects a control resource set based on the above-described criteria, the terminal may additionally consider the following two items regarding the QCL information set in the control resource set. First, if control resource set 1 has CSI-RS 1 as a reference signal having a QCL-TypeD relationship, and the reference signal of this CSI-RS 1 having a QCL-TypeD relationship is SSB 1, and another control resource set 2 has a reference signal having a QCL-TypeD relationship that is SSB 1, the terminal may consider that these two control resource sets 1 and 2 have different QCL-TypeD characteristics. Second, if control resource set 1 has CSI-RS 1 set in cell 1 as a reference signal having a QCL-TypeD relationship, and the reference signal of this CSI-RS 1 having a QCL-TypeD relationship is SSB 1, and control resource set 2 has CSI-RS 2 set in cell 2 as a reference signal having a QCL-TypeD relationship, and the reference signal of this CSI-RS 2 having a QCL-TypeD relationship is the same SSB 1, then the terminal can consider that the two control resource sets have the same QCL-TypeD characteristic.

[0237] FIG. 12 is a diagram for explaining a method for selecting a control resource set that can be received by a terminal in consideration of priorities when receiving a downlink control channel in a wireless communication system according to an embodiment of the present disclosure. For example, the terminal may be configured to receive multiple control resource sets that overlap in time in a specific PDCCH monitoring period (1210), and these multiple control resource sets may be connected to a common search space or a terminal-specific search space for multiple cells. Within the PDCCH monitoring period, a first control resource set (1215) connected to the first common search space may exist within a first bandwidth portion (1200) of a first cell, and a first control resource set (1220) connected to the first common search space and a second control resource set (1225) connected to the second terminal-specific search space may exist within a first bandwidth portion (1205) of a second cell. Control resource sets (1215) and (1220) may have a relationship of QCL-TypeD with the 1st CSI-RS resource set within the 1st bandwidth portion of the 1st cell, and control resource set (1225) may have a relationship of QCL-TypeD with the 1st CSI-RS resource set within the 1st bandwidth portion of the 2nd cell. Therefore, when criterion 1 is applied to the corresponding PDCCH monitoring section (1210), all other control resource sets having the same QCL-TypeD reference signal as the 1st control resource set (1215) can be received. Therefore, the terminal can receive control resource sets (1215) and (1220) in the corresponding PDCCH monitoring section (1210). As another example, a terminal may be configured to receive multiple control resource sets that overlap in time in a specific PDCCH monitoring interval (1240), and these multiple control resource sets may be associated with a common search space or a terminal-specific search space for multiple cells.Within the corresponding PDCCH monitoring section, within the first bandwidth portion (1230) of the first cell, there may exist a first control resource set (1245) connected to the first terminal-specific search section and a second control resource set (1250) connected to the second terminal-specific search section, and within the first bandwidth portion (1235) of the second cell, there may exist a first control resource set (1255) connected to the first terminal-specific search section and a second control resource set (1260) connected to the third terminal-specific search section. Control resource sets (1245) and (1250) have a relationship with the 1st CSI-RS resource set in the 1st bandwidth part of the 1st cell and QCL-TypeD, control resource set (1255) has a relationship with the 1st CSI-RS resource set in the 1st bandwidth part of the 2nd cell and QCL-TypeD, and control resource set (1260) can have a relationship with the 2nd CSI-RS resource set in the 1st bandwidth part of the 2nd cell and QCL-TypeD. However, if criterion 1 is applied to the corresponding PDCCH monitoring section (1240), there is no common search section, so the next criterion, criterion 2, can be applied. If criterion 2 is applied to the corresponding PDCCH monitoring section (1240), all other control resource sets having the same QCL-TypeD reference signal as the control resource set (1245) can be received. Accordingly, the terminal can receive control resource sets (1245) and (1250) in the corresponding PDCCH monitoring section (1240).

[0238] [Rate matching / Puncturing related]

[0239] Below, the rate matching operation and puncturing operation are described in detail.

[0240] When a time and frequency resource A, through which an arbitrary symbol sequence A is to be transmitted, overlaps with an arbitrary time and frequency resource B, a rate matching or puncturing operation may be considered for transmission and reception operations of channel A considering resource C, an area in which resources A and B overlap. The specific operations may follow the contents below.

[0241] Rate Matching Operation

[0242] - The base station can map and transmit channel A only for the remaining resource areas excluding resource C corresponding to the overlapping area with resource B among the entire resources A that want to transmit symbol sequence A to the terminal. For example, if symbol sequence A is composed of {symbol #1, symbol #2, symbol #3, symbol #4}, resource A is {resource #1, resource #2, resource #3, resource #4}, and resource B is {resource #3, resource #5}, the base station can sequentially map and transmit symbol sequence A to the remaining resources {resource #1, resource #2, resource #4} excluding {resource #3} corresponding to resource C, the overlapping area between resources A and B, among resources A. As a result, the base station can map and transmit symbol sequence {symbol #1, symbol #2, symbol #3} to {resource #1, resource #2, resource #4}, respectively.

[0243] The terminal can determine resources A and B from scheduling information for symbol sequence A received from the base station, and can thereby determine resource C, which is an area where resources A and B overlap. The terminal can receive symbol sequence A, assuming that symbol sequence A was mapped and transmitted in the remaining area excluding resource C among the entire resources A. For example, if symbol sequence A is composed of {symbol #1, symbol #2, symbol #3, symbol #4}, resource A is {resource #1, resource #2, resource #3, resource #4}, and resource B is {resource #3, resource #5}, the terminal can receive symbol sequence A, assuming that symbol sequence A was sequentially mapped to {resource #1, resource #2, resource #4}, which are the remaining resources among resources A excluding {resource #3} corresponding to resource C. As a result, the terminal can assume that the symbol sequence {symbol #1, symbol #2, symbol #3} is transmitted by being mapped to {resource #1, resource #2, resource #4}, respectively, and perform a series of subsequent receiving operations.

[0244] Puncture action

[0245] If a base station wants to transmit symbol sequence A to a terminal, and there is a resource C corresponding to an area overlapping with resource B among all resources A, the base station maps symbol sequence A to the entire resource A, but does not perform transmission in the resource area corresponding to resource C, and can perform transmission only for the remaining resource areas of resource A excluding resource C. For example, if symbol sequence A is composed of {symbol #1, symbol #2, symbol #3, symbol #4}, resource A is {resource #1, resource #2, resource #3, resource #4}, and resource B is {resource #3, resource #5}, the base station can map symbol sequence A {symbol #1, symbol #2, symbol #3, symbol #4} to resource A {resource #1, resource #2, resource #3, resource #4}, and transmit only symbol sequences {symbol #1, symbol #2, symbol #4} corresponding to resources {resource #1, resource #2, resource #4}, which are the remaining resources except {resource #3} corresponding to resource C among resources A, and may not transmit {symbol #3} mapped to {resource #3} corresponding to resource C. As a result, the base station can transmit symbol sequences {symbol #1, symbol #2, symbol #4} by mapping them to {resource #1, resource #2, resource #4}, respectively.

[0246] The terminal can determine resources A and B from scheduling information for symbol sequence A from the base station, and can thereby determine resource C, which is an area where resources A and B overlap. The terminal can receive symbol sequence A assuming that symbol sequence A is mapped to the entire resource A and transmitted only in the remaining area of ​​resource area A excluding resource C. For example, if symbol sequence A is composed of {symbol #1, symbol #2, symbol #3, symbol #4}, resource A is {resource #1, resource #2, resource #3, resource #4}, and resource B is {resource #3, resource #5}, the terminal can assume that symbol sequence A {symbol #1, symbol #2, symbol #3, symbol #4} is mapped to resource A {resource #1, resource #2, resource #3, resource #4} respectively, but {symbol #3} mapped to {resource #3} corresponding to resource C is not transmitted, and can receive it assuming that symbol sequence {symbol #1, symbol #2, symbol #4} corresponding to {resource #1, resource #2, resource #4}, which are the remaining resources among resource A except {resource #3} corresponding to resource C, are mapped and transmitted. As a result, the terminal can assume that the symbol sequence {symbol #1, symbol #2, symbol #4} is transmitted by being mapped to {resource #1, resource #2, resource #4}, respectively, and perform a series of subsequent receiving operations.

[0247] Below, we describe a method for configuring rate-matching resources for the purpose of rate-matching in 5G communication systems. Rate-matching refers to adjusting the size of a signal based on the amount of resources available for transmission. For example, rate-matching a data channel may mean adjusting the size of data accordingly, without mapping the data channel to a specific time and frequency resource region.

[0248] Figure 11 is a diagram for explaining a method in which a base station and a terminal transmit and receive data by considering downlink data channels and rate matching resources.

[0249] FIG. 11 illustrates a downlink data channel (PDSCH, 1101) and a rate matching resource (1102). A base station can configure one or more rate matching resources (1102) to a terminal through upper layer signaling (e.g., RRC signaling). The rate matching resource (1102) configuration information can include time-domain resource allocation information (1103), frequency-domain resource allocation information (1104), and period information (1105). In the following, the bitmap corresponding to the frequency-domain resource allocation information (1104) is named "the first bitmap", the bitmap corresponding to the time-domain resource allocation information (1103) is named "the second bitmap", and the bitmap corresponding to the period information (1105) is named "the third bitmap". When all or part of the time and frequency resources of a scheduled data channel (1101) overlap with the set rate matching resources (1102), the base station can rate-match and transmit the data channel (1101) in the rate matching resource (1102) portion, and the terminal can perform reception and decoding after assuming that the data channel (1101) is rate-matched in the rate matching resource (1102) portion.

[0250] The base station can dynamically notify the terminal via DCI whether to rate-match the data channel in the set rate-matching resource portion through additional configuration (corresponding to the "rate-matching indicator" in the DCI format described above). Specifically, the base station can select some of the set rate-matching resources and group them into rate-matching resource groups, and can use a bitmap to indicate to the terminal via DCI whether the data channel for each rate-matching resource group is rate-matched. For example, if four rate-matching resources, RMR#1, RMR#2, RMR#3, and RMR#4, are set, the base station can set RMG#1={RMR#1, RMR#2}, RMG#2={RMR#3, RMR#4} as the rate-matching groups, and can use two bits in the DCI field to indicate to the terminal whether to rate-match in RMG#1 and RMG#2, respectively, using a bitmap. For example, if rate matching is required, it can be indicated as "1", and if rate matching is not required, it can be indicated as "0".

[0251] 5G supports granularity at the "RB symbol level" and "RE level" by setting the aforementioned rate matching resources on the terminal. More specifically, the following setting method can be followed.

[0252] RB symbol level

[0253] A terminal can set up to four RateMatchPatterns for each bandwidth section through upper layer signaling, and one RateMatchPattern can include the following contents.

[0254] - As a reserved resource within the bandwidth portion, a resource may be included in which the time and frequency resource domains of the reserved resource are set by combining a bitmap at the RB level and a bitmap at the symbol level along the frequency axis. The reserved resource may span one or two slots. A time domain pattern (periodicityAndPattern) in which the time and frequency domains composed of each pair of RB level and symbol level bitmaps are repeated may additionally be set.

[0255] - It may include a time and frequency domain resource area set as a control resource set within the bandwidth portion and a resource area corresponding to a time domain pattern set as a search space setting in which the resource area is repeated.

[0256] RE level

[0257] The terminal can be configured with the following contents through upper layer signaling.

[0258] - The configuration information (lte-CRS-ToMatchAround) for REs corresponding to the LTE CRS (Cell-specific Reference Signal or Common Reference Signal) pattern may include the number of LTE CRS ports (nrofCRS-Ports) and the LTE-CRS-vshift(s) value (v-shift), the location information (carrierFreqDL) of the center subcarrier of the LTE carrier from the reference frequency point (e.g., reference point A), the bandwidth size (carrierBandwidthDL) of the LTE carrier, and the subframe configuration information (mbsfn-SubframConfigList) corresponding to the MBSFN (Multicast-broadcast single-frequency network). Based on the above-described information, the terminal can determine the location of the CRS within the NR slot corresponding to the LTE subframe.

[0259] - May contain configuration information for a set of resources corresponding to one or more ZP (Zero Power) CSI-RSs within the bandwidth portion.

[0260] [Regarding LTE CRS rate match]

[0261] Next, the rate match process for the LTE CRS described above will be described in detail. In order to coexist between LTE (Long Term Evolution) and NR (New RAT) (LTE-NR Coexistence), NR provides a function to set a pattern of LTE's CRS (Cell Specific Reference Signal) to NR terminals. More specifically, the CRS pattern can be provided by RRC signaling including at least one parameter in the ServingCellConfig IE (Information Element) or ServingCellConfigCommon IE. Examples of the parameters can include lte-CRS-ToMatchAround, lte-CRS-PatternList1-r16, lte-CRS-PatternList2-r16, crs-RateMatch-PerCORESETPoolIndex-r16, etc.

[0262] In Rel-15 NR, the lte-CRS-ToMatchAround parameter provides a function that allows one CRS pattern to be set per serving cell. In Rel-16 NR, the function has been extended to allow multiple CRS patterns to be set per serving cell. More specifically, a single-TRP (transmission and reception point) configured terminal can have one CRS pattern set per LTE carrier, and a multi-TRP configured terminal can have two CRS patterns set per LTE carrier. For example, a single-TRP configured terminal can have up to three CRS patterns set per serving cell through the lte-CRS-PatternList1-r16 parameter. As another example, a multi-TRP configured terminal can have CRS set per TRP. That is, the CRS pattern for TRP1 can be set via the lte-CRS-PatternList1-r16 parameter, and the CRS pattern for TRP2 can be set via the lte-CRS-PatternList2-r16 parameter. Meanwhile, when two TRPs are set as above, whether both the CRS patterns of TRP1 and TRP2 or only the CRS pattern for one TRP is applied to a specific PDSCH (Physical Downlink Shared Channel) is determined via the crs-RateMatch-PerCORESETPoolIndex-r16 parameter. When the crs-RateMatch-PerCORESETPoolIndex-r16 parameter is set to enabled, only the CRS pattern of one TRP is applied, and in other cases, the CRS patterns of both TRPs can be applied.

[0263] Table 22 shows a ServingCellConfig IE containing the above CRS pattern, and Table 23 shows a RateMatchPatternLTE-CRS IE containing at least one parameter for the CRS pattern.

[0264] [Table 22]

[0265]

[0266]

[0267] [Table 23]

[0268]

[0269] [PDSCH: Processing Time]

[0270] 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 instruction index (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 Formula 2].

[0271] [Equation 2]

[0272] T proc,1 = ( N1+ d 1,1 + d2)( 2048 + 144 ) k2 -μ T c + T ext

[0273] T as described in mathematical formula 2 proc,1 In , each variable can have the following meanings:

[0274] - 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 24], and if the UE processing capability is reported as 2 and the availability of the UE processing capability 2 is set through upper layer signaling, it may have the value of [Table 25]. 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 the HARQ-ACK is to be transmitted.

[0275] [Table 24] PDSCH processing time when PDSCH processing capability is 1

[0276]

[0277] [Table 25] PDSCH processing time when PDSCH processing capability is 2

[0278]

[0279] - k: 64

[0280] - 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.

[0281] - If l1 indicating the PDSCH DMRS location value is 12, N1,0 in the above [Table x2-2] has a value of 14, otherwise it has a value of 13.

[0282] - 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.

[0283] - d2: When a PUCCH with a high priority index and a PUCCH or PUSCH with a low priority index overlap in time, d2 of the PUCCH with the high priority index may be set to a value reported by the terminal. Otherwise, d2 is 0.

[0284] - If PDSCH mapping type B is used for terminal processing capability 1, 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.

[0285] - L If it's 7, then d 1,1 = 0.

[0286] - L 4 and L If it's 6, d 1,1 = 7 - L.

[0287] - If L 3, d 1,1 = min (d, 1).

[0288] - If L = 2, d 1,1 = 3 + d.

[0289] - If PDSCH mapping type B is used for terminal processing capability 2, d1,1 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.

[0290] - L If it's 7, then d 1,1 = 0.

[0291] - L 4 and L If it's 6, d 1,1 = 7 - L.

[0292] - If L = 2,

[0293] - 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.

[0294] - If not, d 1,1 = d.

[0295] - For a terminal supporting capability 2 within a given serving cell, the PDSCH processing time according to terminal processing capability 2 may be applied if the terminal sets processingType2Enabled, which is an upper layer signaling for the cell, to enable.

[0296] If the position of the first uplink transmission symbol of PUCCH containing HARQ-ACK information (the position can be determined by considering 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,1If 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 general 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.

[0297] [PDSCH: Reception Preparation Time during Cross-Carrier Scheduling]

[0298] 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 different cross-carrier scheduling, N- is the PDSCH reception preparation time of the terminal defined for the time interval between the PDCCH and the PDSCH. pdsch Explains about.

[0299] 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.

[0300] If μ PDCCH > μ PDSCH In this case, the scheduled PDSCH is N from the last symbol of the PDCCH that scheduled the PDSCH. pdschIt can be transmitted from the symbol onwards. The transmission symbol of the corresponding PDSCH can include DM-RS.

[0301] [Table 26] N according to scheduled PDCCH subcarrier interval pdsch

[0302]

[0303] [SRS related]

[0304] Next, we describe an uplink channel estimation method using the Sounding Reference Signal (SRS) transmission of a terminal. The base station can configure at least one SRS configuration for each uplink BWP to convey configuration information for SRS transmission to the terminal, and can also configure at least one SRS resource set for each SRS configuration. For example, the base station and the terminal can exchange the following upper-level signaling information to convey information regarding the SRS resource set.

[0305] - srs-ResourceSetId: SRS resource set index

[0306] - srs-ResourceIdList: A set of SRS resource indices referenced in the SRS resource set.

[0307] - resourceType: This is the time axis transmission setting of the SRS resource referenced in the SRS resource set, and can be set to one of 'periodic', 'semi-persistent', and 'aperiodic'. If set to 'periodic' or 'semi-persistent', associated CSI-RS information can be provided depending on the usage of the SRS resource set. If set to 'aperiodic', an aperiodic SRS resource trigger list and slot offset information can be provided, and associated CSI-RS information can be provided depending on the usage of the SRS resource set.

[0308] - usage: This is a setting for the usage of the SRS resource referenced in the SRS resource set, and can be set to one of 'beamManagement', 'codebook', 'nonCodebook', and 'antennaSwitching'.

[0309] - alpha, p0, pathlossReferenceRS, srs-PowerControlAdjustmentStates: Provides parameter settings for adjusting the transmission power of the SRS resource referenced in the SRS resource set.

[0310] The terminal can understand that the SRS resource included in the set of SRS resource indices referenced in the SRS resource set follows the information set in the SRS resource set.

[0311] In addition, the base station and the terminal can transmit and receive upper layer signaling information to convey individual configuration information for the SRS resource. For example, the individual configuration information for the SRS resource can include time-frequency axis mapping information within the slot of the SRS resource, which can include information about frequency hopping within or between slots of the SRS resource. In addition, the individual configuration information for the SRS resource can include the time axis transmission configuration of the SRS resource, which can be set to one of 'periodic', 'semi-persistent', and 'aperiodic'. This can be restricted to have the same time axis transmission configuration as the SRS resource set including the SRS resource. If the time axis transmission configuration of the SRS resource is set to 'periodic' or 'semi-persistent', the SRS resource transmission period and slot offset (e.g., periodicityAndOffset) can additionally be included in the time axis transmission configuration.

[0312] The base station can activate, deactivate, or trigger SRS transmission to the UE through higher layer signaling, including RRC signaling or MAC CE signaling, or L1 signaling (e.g., DCI). For example, the base station can activate or deactivate periodic SRS transmission to the UE through higher layer signaling. The base station can instruct the UE to activate an SRS resource set with resourceType set to periodic through higher layer signaling, and the UE can transmit an SRS resource referenced in the activated SRS resource set. The time-frequency domain resource mapping within the slot of the transmitted SRS resource follows the resource mapping information set in the SRS resource, and the slot mapping, including the transmission period and slot offset, follows the periodicityAndOffset set in the SRS resource. In addition, the spatial domain transmission filter applied to the transmitted SRS resource can refer to the spatial relation information set in the SRS resource, or the associated CSI-RS information set in the SRS resource set that includes the SRS resource. A terminal can transmit SRS resources within an activated uplink BWP for periodic SRS resources activated through upper layer signaling.

[0313] For example, a base station can activate or deactivate semi-persistent SRS transmission to a terminal through upper layer signaling. The base station can instruct the terminal to activate an SRS resource set through MAC CE signaling, and the terminal can transmit an SRS resource referenced in the activated SRS resource set. The SRS resource set activated through MAC CE signaling can be limited to an SRS resource set with resourceType set to semi-persistent. The time-frequency domain resource mapping within the slot of the transmitted SRS resource follows the resource mapping information configured in the SRS resource, and the slot mapping including the transmission period and slot offset follows the periodicityAndOffset configured in the SRS resource. In addition, the spatial domain transmission filter applied to the transmitted SRS resource can refer to the spatial relation information configured in the SRS resource, or the associated CSI-RS information configured in the SRS resource set that includes the SRS resource. If spatial relation info is configured in an SRS resource, the spatial domain transmission filter can be determined by referring to the configuration information for spatial relation info transmitted through MAC CE signaling that activates semi-persistent SRS transmission without following it. The terminal can transmit SRS resources within the activated uplink BWP for the semi-persistent SRS resource activated through upper layer signaling.

[0314] For example, a base station can trigger aperiodic SRS transmission to a terminal via DCI. The base station can indicate one of the aperiodic SRS resource triggers (aperiodicSRS-ResourceTrigger) via the SRS request field of the DCI. The terminal can understand that an SRS resource set including the aperiodic SRS resource trigger indicated via DCI in the aperiodic SRS resource trigger list among the configuration information of the SRS resource set has been triggered. The terminal can transmit the SRS resource referenced in the triggered SRS resource set. The time-frequency domain resource mapping within the slot of the transmitted SRS resource follows the resource mapping information configured in the SRS resource. In addition, the slot mapping of the transmitted SRS resource can be determined through the slot offset between the PDCCH including the DCI and the SRS resource, which can refer to the value(s) included in the slot offset set configured in the SRS resource set. Specifically, the slot offset between the PDCCH including DCI and the SRS resource may be applied with a value indicated in the time domain resource assignment field of the DCI among the offset value(s) included in the slot offset set configured in the SRS resource set. In addition, the spatial domain transmission filter applied to the transmitted SRS resource may refer to the spatial relation information configured in the SRS resource, or may refer to the associated CSI-RS information configured in the SRS resource set including the SRS resource. The UE may transmit the SRS resource within the activated uplink BWP for the aperiodic SRS resource triggered through the DCI.

[0315] When a base station triggers aperiodic SRS transmission to a terminal through DCI, a minimum time interval may be required between a PDCCH including the DCI that triggers aperiodic SRS transmission and the SRS to be transmitted, so that the terminal can transmit the SRS by applying configuration information for the SRS resource. The time interval for SRS transmission of the terminal can be defined as the number of symbols between the last symbol of the PDCCH including the DCI that triggers aperiodic SRS transmission and the first symbol to which the first SRS resource to be transmitted among the SRS resource(s) is mapped. The minimum time interval can be determined with reference to the PUSCH preparation procedure time required for the terminal to prepare for PUSCH transmission. In addition, the minimum time interval can have different values ​​depending on the usage of the SRS resource set including the SRS resource to be transmitted. For example, the minimum time interval can be determined as N2 symbols, which are defined by considering the terminal processing ability according to the capability of the terminal with reference to the PUSCH preparation procedure time of the terminal. In addition, considering the usage of the SRS resource set including the SRS resource being transmitted, if the usage of the SRS resource set is set to 'codebook' or 'antennaSwitching', the minimum time interval can be set to N2 symbols, and if the usage of the SRS resource set is set to 'nonCodebook' or 'beamManagement', the minimum time interval can be set to N2+14 symbols.The terminal may transmit an aperiodic SRS if the time interval for aperiodic SRS transmission is greater than or equal to the minimum time interval, and may ignore the DCI that triggers the aperiodic SRS if the time interval for aperiodic SRS transmission is less than the minimum time interval.

[0316] [Table 27]

[0317]

[0318] The spatialRelationInfo setting information in [Table 27] above is intended to refer to a single reference signal and apply the beam information of the reference signal to the beam used for the corresponding SRS transmission. For example, the spatialRelationInfo setting may include information such as [Table 28] below.

[0319] [Table 28]

[0320]

[0321] Referring to the above spatialRelationInfo setting, the index of the reference signal to be referenced in order to use the beam information of a specific reference signal, i.e., the SS / PBCH block index, CSI-RS index, or SRS index can be set. The upper signaling referenceSignal is setting information indicating which beam information of which reference signal is to be referenced for the corresponding SRS transmission, ssb-Index means the index of the SS / PBCH block, csi-RS-Index means the index of the CSI-RS, and srs means the index of the SRS, respectively. If the value of the upper signaling referenceSignal is set to 'ssb-Index', the terminal can apply the reception beam used when receiving the SS / PBCH block corresponding to the ssb-Index as the transmission beam of the corresponding SRS transmission. If the value of the upper signaling referenceSignal is set to 'csi-RS-Index', the terminal can apply the reception beam used when receiving the CSI-RS corresponding to the csi-RS-Index as the transmission beam of the corresponding SRS transmission. If the value of the upper signaling referenceSignal is set to 'srs', the terminal can apply the transmission beam used when transmitting the SRS corresponding to the srs as the transmission beam for the corresponding SRS transmission.

[0322] [PUSCH: Transmission method related]

[0323] Next, we describe the scheduling method for PUSCH transmission. PUSCH transmission can be dynamically scheduled by the UL grant within the DCI or can operate by configured grant Type 1 or Type 2. Dynamic scheduling instructions for PUSCH transmission are possible in DCI format 0_0 or 0_1.

[0324] Configured grant Type 1 PUSCH transmission can be semi-statically configured by receiving configuredGrantConfig including rrc-ConfiguredUplinkGrant of [Table 29] through higher-order signaling, without receiving UL grant in DCI. Configured grant Type 2 PUSCH transmission can be semi-persistently scheduled by UL grant in DCI after receiving configuredGrantConfig not including rrc-ConfiguredUplinkGrant of [Table 29] through higher-order signaling. When PUSCH transmission operates by configured grant, parameters applied to PUSCH transmission are applied through configuredGrantConfig of higher-order signaling of [Table 29], except for dataScramblingIdentityPUSCH, txConfig, codebookSubset, maxRank, and scaling of UCI-OnPUSCH provided by pusch-Config of [Table 30]. If the terminal has been provided with transformPrecoder in configuredGrantConfig, which is the upper signaling of [Table 29], the terminal applies tp-pi2BPSK in pusch-Config of [Table 30] to PUSCH transmission operated by the configured grant.

[0325] [Table 29]

[0326]

[0327]

[0328] Next, the PUSCH transmission method is described. The DMRS antenna port for PUSCH transmission is the same as the antenna port for SRS transmission. PUSCH transmission can follow a codebook-based or non-codebook-based transmission method, respectively, depending on whether the value of txConfig in the upper signaling, pusch-Config in [Table 30], is 'codebook' or 'nonCodebook'.

[0329] As described above, PUSCH transmission can be dynamically scheduled via DCI format 0_0 or 0_1, and can be semi-statically configured by configured grant. If the UE is instructed to schedule PUSCH transmission via DCI format 0_0, the UE performs beam configuration for PUSCH transmission using pucch-spatialRelationInfoID corresponding to the UE-specific PUCCH resource corresponding to the minimum ID within the activated uplink BWP within the serving cell, and the PUSCH transmission is based on a single antenna port. The UE does not expect scheduling for PUSCH transmission via DCI format 0_0 within a BWP where a PUCCH resource including pucch-spatialRelationInfo is not configured. If the UE does not configure txConfig in pusch-Config of [Table 30], the UE does not expect to be scheduled with DCI format 0_1.

[0330] [Table 30]

[0331]

[0332] Next, we describe codebook-based PUSCH transmission. Codebook-based PUSCH transmission can be dynamically scheduled via DCI format 0_0 or 0_1, or can operate semi-statically based on a configured grant. When codebook-based PUSCH is dynamically scheduled via DCI format 0_1 ​​or semi-statically configured via a configured grant, the UE determines a precoder for PUSCH transmission based on the SRS Resource Indicator (SRI), Transmission Precoding Matrix Indicator (TPMI), and transmission rank (the number of PUSCH transmission layers).

[0333] At this time, the SRI can be given through the SRS resource indicator field in the DCI or configured through the srs-ResourceIndicator higher-level signaling. The UE is configured with at least one SRS resource when transmitting a codebook-based PUSCH, and can be configured with up to two. When the UE receives an SRI through the DCI, the SRS resource indicated by the SRI refers to the SRS resource corresponding to the SRI among the SRS resources transmitted before the PDCCH containing the SRI. In addition, the TPMI and transmission rank can be given through the precoding information and number of layers fields in the DCI or configured through the precodingAndNumberOfLayers higher-level signaling. The TPMI is used to indicate the precoder applied to the PUSCH transmission. If the UE is configured with one SRS resource, the TPMI is used to indicate the precoder to be applied to the configured one SRS resource. When a terminal is configured with multiple SRS resources, TPMI is used to indicate the precoder to be applied in the SRS resource indicated through SRI.

[0334] The precoder to be used for PUSCH transmission is selected from an uplink codebook having the same number of antenna ports as the nrofSRS-Ports value in the upper layer signaling, SRS-Config. In codebook-based PUSCH transmission, the UE determines the codebook subset based on the TPMI and codebookSubset in the upper layer signaling, pusch-Config. The codebookSubset in the upper layer signaling, pusch-Config, can be set to one of 'fullyAndPartialAndNonCoherent', 'partialAndNonCoherent', or 'nonCoherent' based on the UE capability reported by the UE to the base station. If the UE reported 'partialAndNonCoherent' as the UE capability, the UE does not expect the value of codebookSubset in the upper layer signaling to be set to 'fullyAndPartialAndNonCoherent'. Additionally, if the UE reports 'nonCoherent' as the UE capability, the UE does not expect the value of the upper signaling codebookSubset to be set to 'fullyAndPartialAndNonCoherent' or 'partialAndNonCoherent'. If nrofSRS-Ports in the upper signaling SRS-ResourceSet points to two SRS antenna ports, the UE does not expect the value of the upper signaling codebookSubset to be set to 'partialAndNonCoherent'.

[0335] The terminal can be configured with one SRS resource set in which the usage value in the upper signaling SRS-ResourceSet is set to 'codebook', and one SRS resource in the SRS resource set can be indicated via SRI. If multiple SRS resources are configured in the SRS resource set in which the usage value in the upper signaling SRS-ResourceSet is set to 'codebook', the terminal expects that the value of nrofSRS-Ports in the upper signaling SRS-Resource is set to the same value for all SRS resources.

[0336] The terminal transmits to the base station one or more SRS resources included in the SRS resource set in which the usage value is set to 'codebook' according to upper signaling, and the base station selects one of the SRS resources transmitted by the terminal and instructs the terminal to perform PUSCH transmission using transmission beam information of the corresponding SRS resource. At this time, in codebook-based PUSCH transmission, the SRI is used as information for selecting an index of one SRS resource and is included in the DCI. Additionally, the base station includes in the DCI information indicating the TPMI and rank to be used by the terminal for PUSCH transmission. The terminal performs PUSCH transmission by applying the indicated rank and the precoder indicated by the TPMI based on the transmission beam of the corresponding SRS resource using the SRS resource indicated by the SRI.

[0337] Next, we describe non-codebook-based PUSCH transmission. Non-codebook-based PUSCH transmission can be dynamically scheduled via DCI format 0_0 or 0_1, and can operate semi-statically based on a configured grant. If at least one SRS resource is configured within an SRS resource set in which the usage value in the upper signaling, SRS-ResourceSet, is set to 'nonCodebook', the UE can be scheduled for non-codebook-based PUSCH transmission via DCI format 0_1.

[0338] For an SRS resource set in which the usage value in the upper signaling SRS-ResourceSet is set to 'nonCodebook', the UE can be configured with one connected NZP CSI-RS resource (non-zero power CSI-RS). The UE can perform calculations for a precoder for SRS transmission by measuring the NZP CSI-RS resource connected to the SRS resource set. If the difference between the last received symbol of the aperiodic NZP CSI-RS resource connected to the SRS resource set and the first symbol of the aperiodic SRS transmission at the UE is less than 42 symbols, the UE does not expect information about the precoder for SRS transmission to be updated.

[0339] If the value of resourceType in the upper signaling SRS-ResourceSet is set to 'aperiodic', the connected NZP CSI-RS is indicated by the SRS request field in DCI format 0_1 ​​or 1_1. At this time, if the connected NZP CSI-RS resource is an aperiodic NZP CSI-RS resource, the presence of the connected NZP CSI-RS is indicated when the value of the SRS request field in DCI format 0_1 ​​or 1_1 is not '00'. At this time, the DCI must not indicate cross-carrier or cross BWP scheduling. In addition, if the value of the SRS request indicates the presence of an NZP CSI-RS, the NZP CSI-RS is located in the slot in which the PDCCH including the SRS request field is transmitted. At this time, the TCI states set for the scheduled subcarriers are not set to QCL-TypeD.

[0340] If a periodic or semi-persistent SRS resource set is configured, the associated NZP CSI-RS can be indicated through the associatedCSI-RS in the upper-level signaling SRS-ResourceSet. For non-codebook-based transmission, the UE does not expect the upper-level signaling spatialRelationInfo for the SRS resource and the associatedCSI-RS in the upper-level signaling SRS-ResourceSet to be configured together.

[0341] When multiple SRS resources are configured, the UE can determine the precoder and transmission rank to be applied to PUSCH transmission based on the SRI indicated by the base station. At this time, the SRI can be indicated through the SRS resource indicator field in the DCI or can be configured through the upper signaling srs-ResourceIndicator. Similar to the codebook-based PUSCH transmission described above, when the UE is provided with an SRI through the DCI, the SRS resource indicated by the SRI refers to the SRS resource corresponding to the SRI among the SRS resources transmitted before the PDCCH containing the SRI. The UE can use one or more SRS resources for SRS transmission, and the maximum number of SRS resources that can be simultaneously transmitted in the same symbol within one SRS resource set and the maximum number of SRS resources are determined by the UE capability reported by the UE to the base station. At this time, the SRS resources that the UE simultaneously transmits occupy the same RB. The UE configures one SRS port for each SRS resource. Only one SRS resource set with the usage value set to 'nonCodebook' in the upper signaling SRS-ResourceSet can be set, and up to four SRS resources for non-codebook based PUSCH transmission can be set.

[0342] The base station transmits one NZP-CSI-RS associated with an SRS resource set to the terminal, and the terminal calculates a precoder to be used when transmitting one or more SRS resources within the SRS resource set based on the result measured upon reception of the NZP-CSI-RS. When the terminal transmits one or more SRS resources within the SRS resource set with usage set to 'nonCodebook' to the base station, the terminal applies the calculated precoder, and the base station selects one or more SRS resources from the received one or more SRS resources. At this time, in non-codebook based PUSCH transmission, the SRI represents an index that can express a combination of one or more SRS resources, and the SRI is included in the DCI. At this time, the number of SRS resources indicated by the SRI transmitted by the base station can be the number of transmission layers of the PUSCH, and the terminal transmits the PUSCH by applying the precoder applied to SRS resource transmission to each layer.

[0343] [PUSCH: Preparation time]

[0344] Next, the PUSCH preparation procedure time is described. When the base station schedules a UE to transmit a PUSCH using DCI format 0_0, 0_1, or 0_2, the UE may require a PUSCH preparation procedure time to transmit the PUSCH by applying the transmission method indicated through the DCI (transmission precoding method of SRS resources, number of transmission layers, spatial domain transmission filter). NR takes this into account and defines the PUSCH preparation procedure time. The PUSCH preparation procedure time of the UE can follow the following [Mathematical Formula 3].

[0345] [Equation 3]

[0346] T proc,2 = max(( N2+ d 2,1 + d2)( 2048 + 144 ) k2 -μ T c + T ext + T switch , d 2,2 )

[0347] T as described in mathematical formula 3 proc,2 In , each variable can have the following meanings:

[0348] - N2: The number of symbols determined by the UE processing capability (UE processing capability) 1 or 2 and the numerology μ according to the UE's capability. If UE processing capability 1 is reported according to the UE's capability report, it has the value of [Table 31]. If UE processing capability 2 is reported and the availability of UE processing capability 2 is set through upper layer signaling, it can have the value of [Table 32].

[0349] [Table 31]

[0350]

[0351] [Table 32]

[0352]

[0353] - d 2,1 : The number of symbols set to 0 if all resource elements of the first OFDM symbol of PUSCH transmission are configured to consist of only DM-RS, and 1 otherwise.

[0354] - k: 64

[0355] - μ: or Medium, T proc,2 This follows the larger value. refers to the numerology of the downlink in which the PDCCH containing the DCI for scheduling the PUSCH is transmitted, It refers to the numerology of the uplink in which PUSCH is transmitted.

[0356] - T c : , , , has.

[0357] - d 2,2 : If the DCI scheduling the PUSCH indicates BWP switching, it follows the BWP switching time, otherwise it has 0.

[0358] - d2: When the OFDM symbols of a PUCCH with a high priority index and a PUCCH with a low priority index overlap in time, the d2 value of the PUSCH with the high priority index is used. Otherwise, d2 is 0.

[0359] - T ext : If the terminal uses a shared spectrum channel access method, the terminal is T ext can be calculated and applied to the PUSCH preparation process time. Otherwise, T ext is assumed to be 0.

[0360] - T switch: T when the uplink switching interval is triggered switch is assumed to be the switching interval time. Otherwise, it is assumed to be 0.

[0361] When the base station and the terminal consider the time domain resource mapping information of the PUSCH scheduled through DCI and the influence of the timing advance between uplink and downlink, the base station and the terminal determine T from the last symbol of the PDCCH including the DCI that scheduled the PUSCH. proc,2 If the first symbol of the PUSCH begins before the first uplink symbol of the CP, the PUSCH preparation time is determined to be insufficient. Otherwise, the base station and the UE determine that the PUSCH preparation time is sufficient. The UE transmits the PUSCH only when the PUSCH preparation time is sufficient, and may ignore the DCI scheduling the PUSCH if the PUSCH preparation time is insufficient.

[0362] [PUSCH: Repetitive Transmission Related]

[0363] The following describes in detail the repetitive transmission of uplink data channels in 5G systems. 5G systems support two types of repetitive transmission methods for uplink data channels: PUSCH repetitive transmission type A and PUSCH repetitive transmission type B. A terminal can be configured with either PUSCH repetitive transmission type A or B via upper layer signaling.

[0364] PUSCH repetitive transmission type A

[0365] - As described above, the symbol length and the position of the start symbol of the uplink data channel are determined by the time domain resource allocation method within one slot, and the base station can notify the terminal of the number of repeated transmissions through upper layer signaling (e.g., RRC signaling) or L1 signaling (e.g., DCI).

[0366] - The terminal can repeatedly transmit an uplink data channel with the same length and start symbol as the uplink data channel set based on the number of repeated transmissions received from the base station in consecutive slots. In this case, if at least one symbol among the slots set by the base station to the terminal as downlink or the symbols of the uplink data channel set to the terminal is set as downlink, the terminal skips the uplink data channel transmission, but counts the number of repeated transmissions of the uplink data channel.

[0367] PUSCH repetitive transmission type B

[0368] - As described above, the start symbol and length of the uplink data channel are determined by a time domain resource allocation method within one slot, and the base station can notify the terminal of the number of repetitions through upper signaling (e.g., RRC signaling) or L1 signaling (e.g., DCI).

[0369] - First, the nominal repetition of the uplink data channel is determined based on the start symbol and length of the established uplink data channel as follows. The slot where the nth nominal repetition starts is The symbol given by and starting from that slot is is given by . The slot where the nth nominal repetition ends is The symbol given by and ending in that slot is is given by . Here, n=0,..., numberofrepetitions-1, S represents the start symbol of the established uplink data channel, and L represents the symbol length of the established uplink data channel. indicates the slot in which the PUSCH transmission starts. Indicates the number of symbols per slot.

[0370] - The UE determines an invalid symbol for PUSCH repetition transmission type B. A symbol configured for downlink by tdd-UL-DL-ConfigurationCommon or tdd-UL-DL-ConfigurationDedicated is determined as an invalid symbol for PUSCH repetition transmission type B. Additionally, an invalid symbol can be configured in a higher layer parameter (e.g., InvalidSymbolPattern). The higher layer parameter (e.g., InvalidSymbolPattern) provides a symbol-level bitmap spanning one or two slots, where an invalid symbol can be configured. 1 in the bitmap indicates an invalid symbol. Additionally, the period and pattern of the bitmap can be configured through a higher layer parameter (e.g., periodicityAndPattern). If a higher layer parameter (e.g., InvalidSymbolPattern) is set and the InvalidSymbolPatternIndicator-ForDCIFormat0_1 or InvalidSymbolPatternIndicator-ForDCIFormat0_2 parameter indicates 1, the terminal applies an invalid symbol pattern, and if the parameter indicates 0, the terminal does not apply the invalid symbol pattern. If a higher layer parameter (e.g., InvalidSymbolPattern) is set and the InvalidSymbolPatternIndicator-ForDCIFormat0_1 or InvalidSymbolPatternIndicator-ForDCIFormat0_2 parameter is not set, the terminal applies an invalid symbol pattern.

[0371] After determining invalid symbols, the terminal may consider symbols other than invalid symbols as valid symbols for each nominal repetition. If each nominal repetition includes at least one valid symbol, the nominal repetition may include one or more actual repetitions. Here, each actual repetition includes a contiguous set of valid symbols that can be used for PUSCH repetitive transmission type B within a single slot.

[0372] FIG. 14 is a diagram illustrating an example of PUSCH repetitive transmission type B in a wireless communication system according to an embodiment of the present disclosure. The terminal may set the start symbol S of the uplink data channel to 0, the length L of the uplink data channel to 14, and the number of repetitive transmissions to 16. In this case, the nominal repetition is indicated in 16 consecutive slots (301). Thereafter, the terminal may determine that the symbols set as downlink symbols in each nominal repetition (301) are invalid symbols. In addition, the terminal determines that the symbols set to 1 in the invalid symbol pattern (302) are invalid symbols. If valid symbols that are not invalid symbols in each nominal repetition consist of one or more consecutive symbols in one slot, they are set as actual repetition and transmitted (303).

[0373] Additionally, for PUSCH repetitive transmissions, NR Release 16 can define the following additional methods for UL grant-based PUSCH transmissions across slot boundaries and configured grant-based PUSCH transmissions:

[0374] - Method 1 (mini-slot level repetition): Two or more PUSCH repetitive transmissions are scheduled within a slot or across the boundaries of consecutive slots through a single UL grant. In addition, for Method 1, the time-domain resource allocation information in the DCI indicates the resources of the first repetitive transmission. In addition, the time-domain resource information of the first repetitive transmission and the time-domain resource information of the remaining repetitive transmissions can be determined based on the uplink or downlink direction determined for each symbol in each slot. Each repetitive transmission occupies consecutive symbols.

[0375] - Method 2 (multi-segment transmission): Two or more repeated PUSCH transmissions are scheduled in consecutive slots through a single UL grant. At this time, one transmission is designated for each slot, and each transmission may have a different starting point or repetition length. In addition, in Method 2, the time-domain resource allocation information in the DCI indicates the starting point and repetition length of all repeated transmissions. In addition, when performing repeated transmissions in a single slot through Method 2, if there are multiple sets of consecutive uplink symbols in the slot, each repeated transmission is performed for each set of uplink symbols. If there is only one set of consecutive uplink symbols in the slot, one repeated PUSCH transmission is performed according to the method of NR Release 15.

[0376] - Method 3: Two or more repeated PUSCH transmissions are scheduled in consecutive slots via two or more UL grants. In this case, one transmission is designated for each slot, and the nth UL grant can be received before the PUSCH transmission scheduled for the n-1th UL grant ends.

[0377] - Method 4: One or more PUSCH repetitive transmissions within a single slot, or two or more PUSCH repetitive transmissions across the boundaries of consecutive slots, can be supported through one UL grant or one configured grant. The number of repetitions indicated by the base station to the terminal is only a nominal value, and the number of PUSCH repetitive transmissions actually performed by the terminal may be greater than the nominal number of repetitions. The time-domain resource allocation information in the DCI or configured grant indicates the resources of the first repetitive transmission indicated by the base station. The time-domain resource information of the remaining repetitive transmissions can be determined with reference to at least the resource information of the first repetitive transmission and the uplink or downlink direction of the symbols. If the time-domain resource information of the repetitive transmission indicated by the base station crosses a slot boundary or includes an uplink / downlink switchover point, the repetitive transmission can be divided into multiple repetitive transmissions. In this case, one repetitive transmission can be included for each uplink period within one slot.

[0378] [PUSCH: Frequency Hopping Process]

[0379] Below, frequency hopping of the uplink data channel (Physical Uplink Shared Channel; PUSCH) in a 5G system is described in detail.

[0380] In 5G, two methods are supported for frequency hopping of uplink data channels for each PUSCH repetition transmission type. First, PUSCH repetition transmission type A supports intra-slot frequency hopping and inter-slot frequency hopping, and PUSCH repetition transmission type B supports inter-repetition frequency hopping and inter-slot frequency hopping.

[0381] The intra-slot frequency hopping method supported by PUSCH repetitive transmission type A is a method in which a terminal transmits by changing the allocated resources of the frequency domain by a set frequency offset in two hops within a single slot. In intra-slot frequency hopping, the starting RB of each hop can be expressed using mathematical equation 4.

[0382] [Equation 4]

[0383]

[0384] In Equation 4, i=0 and i=1 represent the first hop and the second hop, respectively. Indicates the starting RB within the UL BWP and is calculated from the frequency resource allocation method. The upper layer parameter indicates the frequency offset between two hops. The number of symbols in the first hop is can be represented as , and the number of symbols in the second hop is can be expressed as is the length of PUSCH transmission within one slot, expressed as the number of OFDM symbols.

[0385] Next, the inter-slot frequency hopping method supported by PUSCH repetitive transmission types A and B is a method in which the terminal changes the allocated resources of the frequency domain by a set frequency offset for each slot and transmits them. In inter-slot frequency hopping, The starting RB during a slot can be expressed by Equation 5.

[0386] [Equation 5]

[0387]

[0388] In mathematical equation 5, is the current slot number in multi-slot PUSCH transmission, Indicates the starting RB within the UL BWP and is calculated from the frequency resource allocation method. Indicates the frequency offset between two hops through upper layer parameters.

[0389] Next, the inter-repetition frequency hopping method supported by PUSCH repetitive transmission type B is to transmit the allocated resources in the frequency domain for one or more actual repetitions within each nominal repetition by shifting them by a set frequency offset. RB is the index of the starting RB in the frequency domain for one or more actual repetitions within the nth nominal repetition. start (n) can follow the following mathematical formula 6.

[0390] [Equation 6]

[0391]

[0392] In mathematical expression 6, n is the index of nominal repetition, Indicates the RB offset between two hops via upper layer parameters.

[0393] [PUSCH: multiplexing rule when AP / SP CSI reporting]

[0394] Hereinafter, a method for measuring and reporting a channel state in a 5G communication system will be described in detail. Channel state information (CSI) may include a channel quality indicator (CQI), a precoding matrix indicator (PMI), a CSI-RS resource indicator (CRI), an SS / PBCH block resource indicator (SSBRI), a layer indicator (LI), a rank indicator (RI), and / or L1-RSRP (Reference Signal Received Power). A base station may control time and frequency resources for the aforementioned CSI measurement and reporting of a terminal.

[0395] For the aforementioned CSI measurement and reporting, the terminal is N( 1) Setting information for CSI reporting (CSI-ReportConfig), M( 1) Setting information for RS transmission resources (CSI-ResourceConfig) and one or two trigger state lists (CSI-AperiodicTriggerStateList, CSI-SemiPersistentOnPUSCH-TriggerStateList) can be configured through upper layer signaling. The configuration information for the aforementioned CSI measurement and reporting can be as described in more detail in [Table 33] to [Table 39] below.

[0396] [Table 33]CSI-ReportConfig

[0397] The IE CSI-ReportConfig is used to configure a periodic or semi-persistent report sent on PUCCH on the cell in which the CSI-ReportConfig is included, or to configure a semi-persistent or aperiodic report sent on PUSCH triggered by DCI received on the cell in which the CSI-ReportConfig is included (in this case, the cell on which the report is sent is determined by the received DCI). See TS 38.214

[0019] , clause 5.2.1.

[0398]

[0399]

[0400]

[0401]

[0402]

[0403] [표 34]CSI-ResourceConfig

[0404] The IE CSI-ResourceConfig defines a group of one or more NZP-CSI-RS-ResourceSet, CSI-IM-ResourceSet and / or CSI-SSB-ResourceSet.

[0405]

[0406]

[0407] [표 35]NZP-CSI-RS-ResourceSet

[0408] The IE NZP-CSI-RS-ResourceSet is a set of Non-Zero-Power (NZP) CSI-RS resources (their IDs) and set-specific parameters.

[0409]

[0410]

[0411] [표 36]CSI-SSB-ResourceSet

[0412] The IE CSI-SSB-ResourceSet is used to configure one SS / PBCH block resource set which refers to SS / PBCH as indicated in ServingCellConfigCommon.

[0413]

[0414] [표 37]CSI-IM-ResourceSet

[0415] The IE CSI-IM-ResourceSet is used to configure a set of one or more CSI Interference Management (IM) resources (their IDs) and set-specific parameters.

[0416]

[0417]

[0418] [표 38]CSI-AperiodicTriggerStateList

[0419] The CSI-AperiodicTriggerStateList IE is used to configure the UE with a list of aperiodic trigger states. Each codepoint of the DCI field "CSI request" is associated with one trigger state. Upon reception of the value associated with a trigger state, the UE will perform measurement of CSI-RS (reference signals) and aperiodic reporting on L1 according to all entries in the associatedReportConfigInfoList for that trigger state.

[0420]

[0421]

[0422] [표 39]CSI-SemiPersistentOnPUSCH-TriggerStateList

[0423] The CSI-SemiPersistentOnPUSCH-TriggerStateList IE is used to configure the UE with list of trigger states for semi-persistent reporting of channel state information on L1. See also TS 38.214

[0019] , clause 5.2.

[0424]

[0425] For the aforementioned CSI report setting (CSI-ReportConfig), each report setting CSI-ReportConfig can be associated with one downlink (DL) bandwidth part identified by the upper layer parameter bandwidth part identifier (bwp-id) given by the CSI resource setting, CSI-ResourceConfig, associated with the corresponding report setting. For the time domain reporting operation for each report setting CSI-ReportConfig, 'Aperiodic', 'Semi-Persistent', and 'Periodic' methods are supported, which can be configured from the base station to the terminal by the reportConfigType parameter configured from the upper layer. The semi-persistent CSI reporting method supports 'PUCCH-based semi-persistent (semi-PersistentOnPUCCH)' and 'PUSCH-based semi-persistent (semi-PersistentOnPUSCH)'. For periodic or semi-permanent CSI reporting methods, the UE can receive PUCCH or PUSCH resources for transmitting CSI from the base station through higher-layer signaling. The period and slot offset of the PUCCH or PUSCH resources for transmitting CSI can be given as numerology of the uplink (UL) bandwidth portion configured for CSI report transmission. For aperiodic CSI reporting methods, the UE can receive scheduling of PUSCH resources for transmitting CSI from the base station through L1 signaling (the aforementioned DCI format 0_1).

[0426] For the CSI resource settings (CSI-ResourceConfig) mentioned above, each CSI resource setting CSI-ReportConfig is S( 1) It may include CSI resource sets (given by the higher layer parameter csi-RS-ResourceSetList). The CSI resource set list may consist of a non-zero power (NZP) CSI-RS resource set and a SS / PBCH block set, or a CSI-interference measurement (CSI-IM) resource set. Each CSI resource setting may be located in a downlink (DL) bandwidth segment identified by the higher layer parameter bwp-id, and a CSI resource setting may be linked to a CSI reporting setting in the same downlink bandwidth segment. The time domain operation of the CSI-RS resources within the CSI resource setting may be set to one of 'aperiodic', 'periodic', or 'semi-persistent' from the higher layer parameter resourceType. For periodic or semi-permanent CSI resource settings, the number of CSI-RS resource sets can be limited to S=1, and the configured period and slot offset can be given as a numerology of a downlink bandwidth portion identified by bwp-id. A terminal can receive one or more CSI resource settings for channel or interference measurement from a base station through higher layer signaling, and may include, for example, the following CSI resources.

[0427] - CSI-IM resources for interference measurements

[0428] - NZP CSI-RS resources for interference measurements

[0429] - NZP CSI-RS resources for channel measurements

[0430] For CSI-RS resource sets associated with resource settings where the upper layer parameter resourceType is set to 'aperiodic', 'periodic', or 'semi-persistent', the trigger state for the CSI report setting where reportType is set to 'aperiodic' and the resource settings for channel or interference measurements for one or more component cells (CCs) can be set with the upper layer parameter CSI-AperiodicTriggerStateList.

[0431] Aperiodic CSI reporting of a terminal can utilize PUSCH, periodic CSI reporting can utilize PUCCH, and semi-persistent CSI reporting can be performed using PUSCH when triggered or activated by DCI, or PUCCH after activation by MAC control element (MAC CE). As mentioned above, CSI resource settings can also be configured as aperiodic, periodic, or semi-persistent. Combinations between CSI reporting settings and CSI resource settings can be supported based on [Table 40] below.

[0432] [Table 40]

[0433]

[0434] Aperiodic CSI reporting can be triggered by the "CSI request" field of the aforementioned DCI format 0_1 ​​corresponding to scheduling DCI for PUSCH. The UE can monitor the PDCCH, acquire the DCI format 0_1, and acquire scheduling information and a CSI request indicator for the PUSCH. The CSI request indicator can be set to NTS (=0, 1, 2, 3, 4, 5, or 6) bits and can be determined by higher layer signaling (reportTriggerSize). One of one or more aperiodic CSI reporting trigger states that can be set by higher layer signaling (CSI-AperiodicTriggerStateList) can be triggered by the CSI request indicator.

[0435] -If all bits in the CSI request field are 0, this may mean that no CSI report is requested.

[0436] -If the number of CSI trigger states (M) in the configured CSI-AperiodicTriggerStateLite is greater than 2NTs-1, then according to the mapping relationship defined, M CSI trigger states can be mapped to 2NTs-1, and one of the trigger states of 2NTs-1 can be indicated by the CSI request field.

[0437] -If the number of CSI trigger states (M) in the configured CSI-AperiodicTriggerStateLite is less than or equal to 2NTs-1, one of the M CSI trigger states can be indicated by the CSI request field.

[0438] [Table 41] below shows an example of the relationship between a CSI request indicator and the CSI trigger state that can be indicated by the indicator.

[0439] [Table 41]

[0440]

[0441] A terminal may perform measurement on a CSI resource within a CSI trigger state triggered by a CSI request field, and may generate CSI (including at least one of the aforementioned CQI, PMI, CRI, SSBRI, LI, RI, or L1-RSRP) therefrom. The terminal may transmit the acquired CSI using a PUSCH scheduled by the corresponding DCI format 0_1. When 1 bit corresponding to the uplink data indicator (UL-SCH indicator) in the DCI format 0_1 ​​indicates "1", the terminal may multiplex and transmit the acquired CSI with uplink data (UL-SCH) on the PUSCH resource scheduled by the DCI format 0_1. When 1 bit corresponding to the uplink data indicator (UL-SCH indicator) in DCI format 0_1 ​​indicates "0", the terminal can transmit only CSI without uplink data (UL-SCH) by mapping it to the PUSCH resource scheduled by DCI format 0_1.

[0442] Figure 13 is a diagram illustrating an example of an aperiodic CSI reporting method.

[0443] In an example (1300) of FIG. 13, the terminal can monitor the PDCCH (1301) to obtain DCI format 0_1, from which scheduling information and CSI request information for the PUSCH (1305) can be obtained. The terminal can obtain resource information for the CSI-RS (1302) to be measured from the received CSI request indicator. The terminal can determine when to perform measurement on the transmitted CSI-RS (1302) resource based on the time point of receiving DCI format 0_1 ​​and the parameter (aperiodicTriggeringOffset described above) for the offset in the CSI resource set configuration (e.g., NZP CSI-RS resource set configuration (NZP-CSI-RS-ResourceSet)). More specifically, the terminal can receive an offset value X of the parameter aperiodicTriggeringOffset in the NZP-CSI-RS resource set configuration from the base station through upper layer signaling, and the set offset value X can mean an offset between a slot in which a DCI that triggers aperiodic CSI reporting is received and a slot in which a CSI-RS resource is transmitted. For example, the aperiodicTriggeringOffset parameter value and the offset value X can have a mapping relationship described in [Table 42] below.

[0444] [Table 42]

[0445]

[0446] An example (1300) of Fig. 13 shows an example in which the offset (1303) value described above is set to X=0. In this case, the terminal can receive the CSI-RS (1302) in the slot (corresponding to slot 0 (1306) of Fig. 13) in which the DCI format 0_1 ​​that triggers the aperiodic CSI report is received, and can report the CSI information measured with the received CSI-RS to the base station through the PUSCH (1305). The terminal can obtain scheduling information (information corresponding to each field of the DCI format 0_1 ​​described above) for the PUSCH (1305) for CSI reporting from the DCI format 0_1. As an example, the terminal can obtain information on the slot in which the PUSCH (1305) is to be transmitted from the time domain resource allocation information for the PUSCH (1305) described above in the DCI format 0_1. In an example (1300) of FIG. 13, the terminal can obtain a K2 (1304) value corresponding to a slot offset value for PDCCH-to-PUSCH as 3. Accordingly, the terminal can transmit in slot 3 (1309), which is 3 slots away from slot 0 (1306), at the time when PUSCH (1305) among slots (1306, 1307, 1308, 1309) receives PDCCH (1301).

[0447] In an example (1310) of FIG. 13, the terminal can monitor the PDCCH (1311) to obtain DCI format 0_1, and can obtain scheduling information and CSI request information for the PUSCH (1315) from this. The terminal can obtain resource information for the CSI-RS (1312) to be measured from the received CSI request indicator. An example (1310) of FIG. 13 shows an example in which the offset (1313) value for the aforementioned CSI-RS is set to X=1. In this case, the terminal can receive the CSI-RS (1312) in slot 1 (1317) to which 1 is applied from the slot (corresponding to slot 0 (1316) of FIG. 13) in which the DCI format 0_1 ​​that triggers aperiodic CSI reporting is received, and can report the CSI measured with the received CSI-RS to the base station through the PUSCH (1315). CSI can be reported from slot 0 (1316) where PDCCH is received among slots (1316, 1317, 1318, 1319) to slot 3 (1319) where K2 (1314) is applied.

[0448] An aperiodic CSI report may include at least one or both of CSI part 1 and CSI part 2, and when the aperiodic CSI report is transmitted via PUSCH, it may be multiplexed with a transport block. For multiplexing, a CRC is inserted into the input bits of the aperiodic CSI, and after encoding and rate matching, it may be mapped to a resource element in the PUSCH in a specific pattern and transmitted. The CRC insertion may be omitted depending on the coding method or the length of the input bits. The number of modulation symbols calculated for rate matching when multiplexing CSI Part 1 or CSI part 2 included in the aperiodic CSI report may be calculated as shown in [Table 43] below.

[0449] [Table 43]

[0450]

[0451]

[0452] In particular, for PUSCH repetition transmission types A and B, the UE can transmit the aperiodic CSI report by multiplexing it only on the first repetition transmission among the PUSCH repetition transmissions. This is because the aperiodic CSI report information to be multiplexed is encoded in a polar code manner, and in order to be multiplexed on multiple PUSCH repetitions, each PUSCH repetition must have the same frequency and time resource allocation. In particular, in the case of PUSCH repetition type B, each actual repetition can have a different OFDM symbol length, so the aperiodic CSI report can be multiplexed and transmitted only on the first PUSCH repetition.

[0453] In addition, for PUSCH repetition transmission scheme B, if the UE schedules aperiodic CSI reporting without scheduling a transport block or receives a DCI activating semi-persistent CSI reporting, the nominal repetition value may be assumed to be 1 even if the number of PUSCH repetition transmissions configured by upper layer signaling is greater than 1. In addition, if the UE schedules or activates aperiodic or semi-persistent CSI reporting without scheduling a transport block based on PUSCH repetition transmission scheme B, the UE may expect the first nominal repetition to be the same as the first actual repetition. For a PUSCH transmitted including semi-persistent CSI based on PUSCH repetition transmission scheme B without scheduling a DCI after semi-persistent CSI reporting is activated by DCI, if the first nominal repetition is different from the first actual repetition, the transmission for the first nominal repetition may be ignored.

[0454] [Regarding terminal capability reporting]

[0455] 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.

[0456] 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 compose a corresponding UE capability information message and report it multiple times. In the next-generation mobile communication 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.

[0457] 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.

[0458] 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 stand-alone (SA). 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. Furthermore, the bands are prioritized in the order listed in FreqBandList.

[0459] 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.

[0460] 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."

[0461] 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 set 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 in the UE-NR-Capabilities and UE-MRDC-Capabilities containers.

[0462] 5. Also, if the requested rat Type is eutra-nr and is influencing, 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.

[0463] 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.

[0464] [CA / DC related]

[0465] FIG. 15 is a diagram illustrating a wireless protocol structure of a base station and a terminal in a single cell, carrier aggregation, and dual connectivity situation according to an embodiment of the present disclosure.

[0466] Referring to FIG. 15, the wireless protocol of the next-generation mobile communication system is composed of NR SDAP (Service Data Adaptation Protocol S25, S70), NR PDCP (Packet Data Convergence Protocol S30, S65), NR RLC (Radio Link Control S35, S60), NR MAC (Medium Access Control S40, S55), and NR PHY (S45, S50) in the terminal and NR base station, respectively.

[0467] The main functions of NR SDAP (S25, S70) may include at least some of the following functions:

[0468] -Transfer of user plane data

[0469] -Mapping between QoS flow and data bearer for both DL and UL

[0470] -QoS flow ID marking function for both uplink and downlink (marking QoS flow ID in both DL and UL packets)

[0471] - Ability to map reflective QoS flow to data bearer for the UL SDAP PDUs (reflective QoS flow to DRB mapping for the UL SDAP PDUs).

[0472] For the above SDAP layer device, the terminal can be configured by RRC message for each PDCP layer device, each bearer, or each logical channel, whether to use the header of the SDAP layer device or whether to use the function of the SDAP layer device, and when the SDAP header is configured, the terminal can be instructed to update or reset the mapping information for the QoS flow and data bearer of the uplink and downlink through the NAS QoS reflection configuration 1-bit indicator (NAS reflective QoS) and the AS QoS reflection configuration 1-bit indicator (AS reflective QoS) of the SDAP header. The SDAP header can include QoS flow ID information indicating QoS. The QoS information can be used as data processing priority, scheduling information, etc. to support a smooth service.

[0473] The main functions of NR PDCP (S30, S65) may include at least some of the following functions:

[0474] -Header compression and decompression (ROHC only)

[0475] -Transfer of user data function

[0476] - In-sequence delivery of upper layer PDUs

[0477] -Out-of-sequence delivery of upper layer PDUs

[0478] - PDCP PDU reordering for reception

[0479] -Duplicate detection of lower layer SDUs

[0480] -Retransmission function (Retransmission of PDCP SDUs)

[0481] -Ciphering and deciphering functions

[0482] -Timer-based SDU discard in uplink.

[0483] The reordering function of the NR PDCP device above refers to a function of reordering PDCP PDUs received from a lower layer in order based on the PDCP SN (sequence number), and may include a function of transmitting data to an upper layer in the reordered order. Alternatively, the reordering function of the NR PDCP device may include a function of transmitting data directly without considering the order, a function of recording lost PDCP PDUs by reordering the order, a function of reporting a status of lost PDCP PDUs to the transmitting side, and a function of requesting retransmission of lost PDCP PDUs.

[0484] The main functions of NR RLC (S35, S60) may include at least some of the following functions:

[0485] -Data transfer function (Transfer of upper layer PDUs)

[0486] - In-sequence delivery of upper layer PDUs

[0487] -Out-of-sequence delivery of upper layer PDUs

[0488] -ARQ function (Error Correction through ARQ)

[0489] -Concatenation, segmentation, and reassembly of RLC SDUs

[0490] -Re-segmentation of RLC data PDUs

[0491] -Reordering of RLC data PDUs

[0492] -Duplicate detection function

[0493] -Protocol error detection

[0494] -RLC SDU discard function

[0495] -RLC re-establishment function

[0496] In the above, the in-sequence delivery function of the NR RLC device refers to the function of sequentially delivering RLC SDUs received from a lower layer to an upper layer. The in-sequence delivery function of the NR RLC device may include a function of reassembling and delivering a single RLC SDU when it is received divided into multiple RLC SDUs, a function of rearranging received RLC PDUs based on the RLC SN (sequence number) or PDCP SN (sequence number), a function of recording lost RLC PDUs by rearranging the order, a function of reporting the status of lost RLC PDUs to the transmitting side, and a function of requesting retransmission of lost RLC PDUs. The in-sequence delivery function of an NR RLC device may include a function to sequentially deliver to the upper layer only the RLC SDUs up to the lost RLC SDU when there is a lost RLC SDU, or may include a function to sequentially deliver to the upper layer all RLC SDUs received before the timer starts if a predetermined timer has expired even if there is a lost RLC SDU. Alternatively, the in-sequence delivery function of an NR RLC device may include a function to sequentially deliver to the upper layer all RLC SDUs received up to the present if a predetermined timer has expired even if there is a lost RLC SDU.In addition, the RLC PDUs may be processed in the order in which they are received (in the order of arrival, regardless of the order of the sequence number) and delivered to the PDCP device out of order (out-of-sequence delivery). In the case of segments, the segments stored in the buffer or to be received later may be received, reconstructed into a complete RLC PDU, processed, and delivered to the PDCP device. The NR RLC layer may not include a concatenation function, and the function may be performed in the NR MAC layer or replaced with a multiplexing function of the NR MAC layer.

[0497] The out-of-sequence delivery function of the NR RLC device above refers to the function of directly delivering RLC SDUs received from a lower layer to an upper layer regardless of the order, and may include a function of reassembling and delivering RLC SDUs when an original RLC SDU is received divided into multiple RLC SDUs, and may include a function of storing the RLC SN or PDCP SN of received RLC PDUs and arranging the order to record lost RLC PDUs.

[0498] NR MAC (S40, S55) can be connected to multiple NR RLC layer devices configured in one terminal, and the main functions of NR MAC can include at least some of the following functions.

[0499] -Mapping function (Mapping between logical channels and transport channels)

[0500] - Multiplexing and demultiplexing functions (Multiplexing / demultiplexing of MAC SDUs)

[0501] -Scheduling information reporting function

[0502] -HARQ function (Error correction through HARQ)

[0503] -Priority handling between logical channels of one UE

[0504] -Priority handling between UEs by means of dynamic scheduling

[0505] -MBMS service identification function

[0506] -Transport format selection function

[0507] -Padding function

[0508] The NR PHY layer (S45, S50) can perform operations such as channel coding and modulating upper layer data, converting it into OFDM symbols and transmitting it over a wireless channel, or demodulating and channel decoding OFDM symbols received over a wireless channel and transmitting them to a higher layer.

[0509] The above wireless protocol structure can have various detailed structures depending on the carrier (or cell) operation method. For example, when a base station transmits data to a terminal based on a single carrier (or cell), the base station and the terminal use a protocol structure with a single structure for each layer, such as S00. On the other hand, when a base station transmits data to a terminal based on CA (carrier aggregation) that uses multiple carriers in a single TRP, the base station and the terminal use a protocol structure that has a single structure up to RLC, such as S10, but multiplexes the PHY layer through the MAC layer. As another example, when a base station transmits data to a terminal based on DC (dual connectivity) that uses multiple carriers in multiple TRPs, the base station and the terminal have a single structure up to PDCP, such as S20, but have multiple structures from the RLC layer onward.

[0510] Referring to the above-described PDCCH and beam configuration-related descriptions, the current Rel-15 and Rel-16 NR do not support PDCCH repetitive transmission, making it difficult to achieve the required reliability in scenarios requiring high reliability, such as URLLC. The present disclosure provides a method for repetitively transmitting PDCCHs through multiple transmission points (TRPs) to improve PDCCH reception reliability at a terminal. Specific methods are described in detail in the following examples.

[0511] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the attached drawings. The contents of the present disclosure can be applied to FDD and TDD systems. In the present disclosure below, upper signaling (or upper layer signaling) refers to a signal transmission method in which a base station transmits a signal to a terminal using a downlink data channel of a physical layer, or a terminal transmits a signal to a base station using an uplink data channel of a physical layer, and may also be referred to as RRC signaling, PDCP signaling, or MAC (medium access control) control element (MAC control element; MAC CE).

[0512] In the present disclosure, when determining whether cooperative communication is applied, the terminal may use various methods, such as having the PDCCH(s) that allocate the PDSCH to which cooperative communication is applied have a specific format, or including a specific indicator that indicates whether cooperative communication is applied, or scrambled with a specific RNTI by the PDCCH(s) that allocate the PDSCH to which cooperative communication is applied, or assuming cooperative communication is applied in a specific section indicated by a higher layer. For the convenience of the following description, the case where the terminal receives the PDSCH to which cooperative communication is applied based on conditions similar to the above will be referred to as the NC-JT case.

[0513] In the present disclosure, determining the priority between A and B may be referred to in various ways, such as selecting a higher priority according to a predetermined priority rule and performing an action corresponding to it, or omitting or dropping an action for a lower priority.

[0514] In the following disclosure, the above examples are described through a number of embodiments, but they are not independent and one or more embodiments may be applied simultaneously or in combination.

[0515] [NC-JT related]

[0516] According to one embodiment of the present disclosure, Non-Coherent Joint Transmission (NC-JT) may be used for a terminal to receive PDSCH from multiple TRPs.

[0517] Unlike existing systems, 5G wireless communication systems can support not only services requiring high transmission speeds, but also services with very short transmission delays and high connection density. In a wireless communication network comprising multiple cells, transmission and reception points (TRPs), or beams, coordinated transmission between each cell, TRP, or / and beam can increase the signal strength received by a terminal or efficiently control interference between each cell, TRP, or / and beam, thereby satisfying diverse service requirements.

[0518] Joint Transmission (JT) is a representative transmission technology for the aforementioned cooperative communication, which increases the signal strength or processing rate received by a terminal by transmitting a signal to a single terminal through a number of different cells, TRPs, or / and beams. At this time, the channel between each cell, TRP, or / and beam and the terminal may have significantly different characteristics, and in particular, in the case of Non-Coherent Joint Transmission (NC-JT) that supports non-coherent precoding between each cell, TRP, or / and beam, individual precoding, MCS, resource allocation, TCI indication, etc. may be required depending on the channel characteristics of each link between each cell, TRP, or / and beam and the terminal.

[0519] The above-described NC-JT transmission can be applied to at least one channel among a downlink data channel (PDSCH: physical downlink shared channel), a downlink control channel (PDCCH: physical downlink control channel), an uplink data channel (PUSCH: physical uplink shared channel), and an uplink control channel (PUCCH: physical uplink control channel). When transmitting a PDSCH, transmission information such as precoding, MCS, resource allocation, and TCI are indicated as DL DCI, and for NC-JT transmission, the transmission information must be independently indicated for each cell, TRP, or / and beam. This is a major factor that increases the payload required for DL ​​DCI transmission, which may adversely affect the reception performance of the PDCCH transmitting the DCI. Therefore, in order to support JT of the PDSCH, it is necessary to carefully design a tradeoff between the amount of DCI information and the reception performance of control information.

[0520] FIG. 16 is a diagram illustrating an example of antenna port configuration and resource allocation for transmitting a PDSCH using cooperative communication in a wireless communication system according to an embodiment of the present disclosure.

[0521] Referring to FIG. 16, examples for PDSCH transmission are explained for each technique of joint transmission (JT), and examples for allocating radio resources for each TRP are shown.

[0522] Referring to FIG. 16, an example (N000) for coherent joint transmission (C-JT) supporting coherent precoding between each cell, TRP or / and beam is illustrated.

[0523] In the case of C-JT, TRP A (N005) and TRP B (N010) transmit a single data (PDSCH) to a terminal (N015), and joint precoding can be performed on multiple TRPs. This may mean that DMRS is transmitted through the same DMRS ports for TRP A (N005) and TRP B (N010) to transmit the same PDSCH. For example, TRP A (N005) and TRP B (N010) may each transmit DRMS ​​to the terminal through DMRS port A and DMRS B. In this case, the terminal may receive one DCI information for receiving one PDSCH that is demodulated based on the DMRS transmitted through DMRS port A and DMRS B.

[0524] Figure 16 shows an example (N020) of Non-Coherent Joint Transmission (NC-JT) supporting non-coherent precoding between each cell, TRP (N025, N030) or / and beam for PDSCH transmission.

[0525] In the case of NC-JT, PDSCH is transmitted to the terminal (N035) for each cell, TRP or / and beam, and individual precoding can be applied to each PDSCH. Each cell, TRP or / and beam transmits a different PDSCH or a different PDSCH layer to the terminal, thereby improving the throughput compared to single cell, TRP or / and beam transmission. In addition, each cell, TRP or / and beam repeatedly transmits the same PDSCH to the terminal, thereby improving the reliability compared to single cell, TRP or / and beam transmission. For convenience of explanation, cells, TRPs or / and beams are collectively referred to as TRPs hereinafter.

[0526] At this time, various radio resource allocations can be considered, such as when the frequency and time resources used by multiple TRPs for PDSCH transmission are all the same (N040), when the frequency and time resources used by multiple TRPs do not overlap at all (N045), and when some of the frequency and time resources used by multiple TRPs overlap (N050).

[0527] To support NC-JT, DCIs of various forms, structures, and relationships can be considered to simultaneously allocate multiple PDSCHs to a single terminal.

[0528] FIG. 17 is a diagram illustrating an example of a configuration of downlink control information (DCI) for NC-JT in which each TRP transmits a different PDSCH or a different PDSCH layer to a terminal in a wireless communication system according to an embodiment of the present disclosure.

[0529] Referring to FIG. 17, case #1 (N100) is an example in which, in addition to the serving TRP (TRP#0) used for single PDSCH transmission, (N-1) different PDSCHs are transmitted from (N-1) additional TRPs (TRP#1 to TRP#(N-1)), and control information for PDSCHs transmitted from the (N-1) additional TRPs is transmitted independently from the control information for the PDSCHs transmitted from the serving TRP. That is, the UE can obtain control information for PDSCHs transmitted from different TRPs (TRP#0 to TRP#(N-1)) through independent DCIs (DCI#0 to DCI#(N-1)). The formats between the independent DCIs may be the same or different, and the payloads between the DCIs may also be the same or different. In the aforementioned case #1, each PDSCH control or allocation freedom can be fully guaranteed, but if each DCI is transmitted in different TRPs, coverage differences may occur for each DCI, which may deteriorate reception performance.

[0530] Case #2 (N105) shows an example in which (N-1) different PDSCHs are transmitted from (N-1) additional TRPs (TRP#1 to TRP#(N-1)) in addition to the serving TRP (TRP#0) used for single PDSCH transmission, and control information (DCI) for the PDSCHs of the (N-1) additional TRPs is transmitted respectively, and each of these DCIs is dependent on the control information for the PDSCH transmitted from the serving TRP.

[0531] For example, in the case of DCI#0, which is control information for a PDSCH transmitted from a serving TRP (TRP#0), it includes all information elements of DCI format 1_0, DCI format 1_1, and DCI format 1_2, but in the case of shortened DCI (hereinafter, sDCI) (sDCI#0 to sDCI#(N-2)), which is control information for PDSCHs transmitted from cooperative TRPs (TRP#1 to TRP#(N-1)), it may include only some of the information elements of DCI format 1_0, DCI format 1_1, and DCI format 1_2. Therefore, in the case of sDCI, which transmits control information for PDSCHs transmitted from cooperative TRPs, since the payload is smaller than that of normal DCI (nDCI), which transmits PDSCH-related control information transmitted from a serving TRP, it is possible to include reserved bits compared to nDCI.

[0532] In the aforementioned case #2, the degree of freedom in controlling or allocating each PDSCH may be limited depending on the content of the information elements included in sDCI, but since the reception performance of sDCI is superior to that of nDCI, the probability of a difference in coverage by DCI may be reduced.

[0533] Case #3 (N110) shows an example in which (N-1) different PDSCHs are transmitted from (N-1) additional TRPs (TRP#1 to TRP#(N-1)) other than the serving TRP (TRP#0) used for single PDSCH transmission, one control information for the PDSCHs of the (N-1) additional TRPs is transmitted, and this DCI is dependent on the control information for the PDSCH transmitted from the serving TRP.

[0534] For example, in the case of DCI#0, which is control information for PDSCH transmitted from a serving TRP (TRP#0), it includes all information elements of DCI format 1_0, DCI format 1_1, and DCI format 1_2, and in the case of control information for PDSCHs transmitted from cooperative TRPs (TRP#1 to TRP#(N-1)), it is possible to collect only some of the information elements of DCI format 1_0, DCI format 1_1, and DCI format 1_2 into one 'secondary' DCI (sDCI) and transmit them. For example, the sDCI may include at least one piece of information among HARQ-related information such as frequency domain resource assignment, time domain resource assignment, and MCS of cooperative TRPs. In addition, for information not included in sDCI, such as BWP (bandwidth part) indicator or carrier indicator, the DCI (DCI#0, normal DCI, nDCI) of serving TRP can be followed.

[0535] Case #3 (N110) may limit the degree of freedom in controlling or allocating each PDSCH depending on the content of the information element included in sDCI, but it is possible to control the reception performance of sDCI and the complexity of blind decoding of DCI of the terminal may be reduced compared to case #1 (N100) or case #2 (N105).

[0536] Case #4 (N115) is an example of transmitting control information for PDSCHs transmitted from (N-1) additional TRPs (TRP#1 to TRP#(N-1)) other than the serving TRP (TRP#0) used for single PDSCH transmission in the same DCI (Long DCI) as the control information for PDSCHs transmitted from the serving TRP. That is, the UE can obtain control information for PDSCHs transmitted from different TRPs (TRP#0 to TRP#(N-1)) through a single DCI. In case #4 (N115), the complexity of DCI blind decoding of the UE may not increase, but the number of cooperative TRPs may be limited due to the long DCI payload limitation, and thus the degree of freedom in PDSCH control or allocation may be low.

[0537] In the following description and examples, sDCI may refer to various auxiliary DCIs, such as shortened DCI, secondary DCI, or normal DCI (DCI format 1_0 to 1_1 described above) containing PDSCH control information transmitted in a cooperative TRP, and unless a special limitation is specified, the description is similarly applicable to the various auxiliary DCIs described above.

[0538] In the following description and examples, the aforementioned cases #1 (N100), #2 (N105), and #3 (N110), in which more than one DCI (PDCCH) is used to support NC-JT, may be classified as multiple PDCCH-based NC-JT, and the aforementioned case #4 (N115), in which a single DCI (PDCCH) is used to support NC-JT, may be classified as single PDCCH-based NC-JT. In PDSCH transmission based on multiple PDCCH, a CORESET in which the DCI of the serving TRP (TRP#0) is scheduled and a CORESET in which the DCI of the cooperating TRPs (TRP#1 to TRP#(N-1)) are scheduled may be distinguished. As a method for distinguishing the CORESETs, there may be a method for distinguishing through an upper layer indicator for each CORESET, a method for distinguishing through beam setting for each CORESET, etc. Additionally, in single PDCCH-based NC-JT, instead of a single DCI scheduling multiple PDSCHs, a single PDSCH with multiple layers is scheduled, and the multiple layers described above can be transmitted from multiple TRPs. In this case, the connection relationship between a layer and the TRP transmitting the layer can be indicated through a Transmission Configuration Indicator (TCI) indication for the layer.

[0539] In the embodiments of the present disclosure, “cooperative TRP” may be replaced with various terms such as “cooperative panel” or “cooperative beam” in actual application.

[0540] In the embodiments of the present disclosure, “when NC-JT is applied” can be interpreted in various ways depending on the situation, such as “when a terminal simultaneously receives one or more PDSCHs in one BWP,” “when a terminal simultaneously receives PDSCHs based on two or more TCI (Transmission Configuration Indicator) indications in one BWP,” or “when a PDSCH received by a terminal is associated with one or more DMRS port groups,” but is used as a single expression for convenience of explanation.

[0541] The wireless protocol architecture for NC-JT in the present disclosure can be used in various ways depending on the TRP deployment scenario. For example, when there is no or small backhaul delay between cooperative TRPs, a method using a structure based on MAC layer multiplexing (CA-like method) similar to S10 of FIG. 15 is possible. On the other hand, when the backhaul delay between cooperative TRPs is so large that it cannot be ignored (for example, when more than 2 ms is required for information exchange such as CSI, scheduling, and HARQ-ACK between cooperative TRPs), a method (DC-like method) is possible to secure delay-robust characteristics by using an independent structure for each TRP starting from the RLC layer, similar to S20 of FIG. 15.

[0542] A terminal supporting C-JT / NC-JT can receive C-JT / NC-JT related parameters or setting values ​​from the upper layer configuration and set the RRC parameters of the terminal based on these. For the upper layer configuration, the terminal can utilize UE capability parameters, for example, tci-StatePDSCH. Here, the UE capability parameters, for example, tci-StatePDSCH, can define TCI states for the purpose of PDSCH transmission, and the number of TCI states can be set to 4, 8, 16, 32, 64, 128 in FR1, and 64 and 128 in FR2, and up to 8 states can be set among the set number that can be indicated by 3 bits of the TCI field of the DCI via the MAC CE message. The maximum value 128 means the value indicated by maxNumberConfiguredTCIstatesPerCC in the tci-StatePDSCH parameter included in the capability signaling of the terminal. In this way, a series of configuration processes from upper layer configuration to MAC CE configuration can be applied to a beamforming instruction or beamforming change command for at least one PDSCH in one TRP.

[0543] [Multi-DCI based Multi-TRP]

[0544] According to one embodiment of the present disclosure, a downlink control channel for NC-JT transmission can be established based on a Multi-PDCCH.

[0545] In NC-JT based on multiple PDCCHs, when transmitting DCI for the PDSCH schedule of each TRP, a CORESET or search space can be distinguished for each TRP. The CORESET or search space for each TRP can be configured as in at least one of the following cases.

[0546] * Setting of upper layer index for each CORESET: The CORESET setting information set as an upper layer may include an index value, and the TRP transmitting the PDCCH in the corresponding CORESET may be distinguished by the set index value for each CORESET. That is, in a set of CORESETs with the same upper layer index value, it may be considered that the same TRP transmits the PDCCH, or it may be considered that a PDCCH scheduling the PDSCH of the same TRP is transmitted. The above-described index for each CORESET may be named as CORESETPoolIndex, and for CORESETs with the same CORESETPoolIndex value set, it may be considered that the PDCCH is transmitted from the same TRP. For a CORESET for which the CORESETPoolIndex value is not set, it may be considered that the default value of CORESETPoolIndex is set, and the above-described default value may be 0.

[0547] * Multiple PDCCH-Config settings: Multiple PDCCH-Configs are configured within one BWP, and each PDCCH-Config can include PDCCH settings for each TRP. That is, a list of CORESETs for each TRP and / or a list of search spaces for each TRP can be configured in one PDCCH-Config, and one or more CORESETs and one or more search spaces included in one PDCCH-Config can be considered to correspond to a specific TRP.

[0548] * CORESET Beam / Beam Group Configuration: The TRP corresponding to the CORESET can be distinguished through the beam or beam group configured for each CORESET. For example, if the same TCI state is set for multiple CORESETs, the CORESETs can be considered to be transmitted through the same TRP, or the PDCCH that schedules the PDSCH of the same TRP can be considered to be transmitted in the CORESET.

[0549] * Search space beam / beam group configuration: A beam or beam group is configured for each search space, and this allows TRPs for each search space to be distinguished. For example, if the same beam / beam group or TCI state is set for multiple search spaces, it can be considered that the same TRP transmits a PDCCH in the corresponding search space, or that a PDCCH that schedules the PDSCH of the same TRP is transmitted in the corresponding search space.

[0550] By dividing the CORESET or search space by TRP as described above, PDSCH and HARQ-ACK information classification for each TRP is possible, and this enables independent HARQ-ACK codebook generation and independent PUCCH resource use for each TRP.

[0551] The above settings can be independent for each cell or BWP. For example, a PCell may have two different CORESETPoolIndex values, while a specific SCell may not have a CORESETPoolIndex value set. In this case, it can be assumed that NC-JT transmission is configured for the PCell, while NC-JT transmission is not configured for the SCell without the CORESETPoolIndex value set.

[0552] [Single-DCI based Multi-TRP]

[0553] According to another embodiment of the present disclosure, a downlink beam for NC-JT transmission can be set based on a Single-PDCCH.

[0554] In single PDCCH-based NC-JT, PDSCHs transmitted by multiple TRPs can be scheduled with a single DCI. At this time, the number of TCI states can be used as a method for indicating the number of TRPs transmitting the corresponding PDSCH. That is, if the number of TCI states indicated in the DCI scheduling the PDSCH is two, it can be considered as a single PDCCH-based NC-JT transmission, and if the number of TCI states is one, it can be considered as a single-TRP transmission. The TCI states indicated in the above DCI can correspond to one or both of the TCI states activated by MAC-CE. When the TCI states of the DCI correspond to two TCI states activated by MAC-CE, a correspondence relationship is established between the TCI codepoint indicated in the DCI and the TCI states activated by MAC-CE, and this can be the case when there are two TCI states activated by MAC-CE corresponding to the above TCI codepoint.

[0555] The above configuration can be independent on a per-cell or per-BWP basis. For example, a PCell may have up to two activated TCI states corresponding to a single TCI codepoint, while a specific SCell may have up to one activated TCI state corresponding to a single TCI codepoint. In this case, it can be assumed that NC-JT transmission is configured on the PCell, while NC-JT transmission is not configured on the aforementioned SCell.

[0556] [PHR]

[0557] Figure 18 illustrates a procedure for a base station to control the transmission power of a terminal in a cellular system. In step 18-10 of Figure 18, a terminal within the coverage of the base station can perform downlink synchronization with the base station and acquire system information. In some embodiments, downlink synchronization can be achieved through a synchronization signal PSS / SSS (Primary Synchronization Signal / Secondary Synchronization Signal) received from the base station. Terminals that have performed downlink synchronization can receive a Master Information Block (MIB) and a System Information Block (SIB) from the base station and acquire system information. In step 18-15, the terminal can perform uplink synchronization with the base station through a random access procedure and establish an RRC (Radio Resource Control) connection. In the random access procedure, the terminal can transmit a random access preamble and message 3 (msg3) to the base station through the uplink. At this time, uplink transmission power can be controlled during transmission of the random access preamble and message 3. Specifically, the terminal can receive parameters for uplink transmission power control from the base station through acquired system information, for example, SIB, or can control the uplink transmission power using promised parameters. In another embodiment of the present disclosure, the terminal can measure the RSRP (Reference Signal Received Power) from the path attenuation estimation signal transmitted by the base station and estimate the downlink path attenuation value as in [Mathematical Formula 7]. And, based on the estimated path attenuation value, the uplink transmission power value for transmitting the random access preamble and message 3 can be set.

[0558] [Equation 7]

[0559] Downlink path loss = base station signal transmission power - RSRP measured by terminal

[0560] In [Mathematical Formula 7], the transmission power of the base station signal refers to the transmission power of the downlink path attenuation estimation signal transmitted by the base station. The downlink path attenuation estimation signal transmitted by the base station may be a Cell-specific Reference Signal (CRS) or a Synchronization Signal Block (SSB). If the path attenuation estimation signal is a Cell-specific Reference Signal (CRS), the transmission power of the base station signal refers to the transmission power of the CRS, and can be transmitted to the terminal through the referenceSignalPower parameter of the system information. If the path attenuation estimation signal is a Synchronization Signal Block (SSB), the transmission power of the base station signal refers to the transmission power of the Secondary Synchronization Signal (SSS) and the Demodulation Reference Signal (DMRS) transmitted on the PBCH, and can be transmitted to the terminal through the ss-PBCH-BlockPower parameter of the system information. In steps 18-20, the UE may receive RRC parameters for uplink transmission power control from the base station through UE-specific RRC or common RRC. The received transmission power control parameters may differ depending on the type of uplink channel and signal transmitted in the uplink. That is, the transmission power control parameters applied to transmission of the physical uplink control channel (PUCCH), the physical uplink shared channel (PUSCH), and the sounding reference signal (SRS) may differ from each other.In addition, as described above, the transmission power control parameters that the terminal receives from the base station through SIB before the RRC connection is established or the transmission power control parameters that the terminal used as pre-agreed values ​​before the RRC connection is established may be included in the RRC parameters transmitted from the base station after the RRC connection is established. The terminal may use the RRC parameter values ​​received from the base station after the RRC connection is established for uplink transmission power control. In steps 18-25, the terminal may receive a path loss estimation signal from the base station. More specifically, the base station may configure a CSI-RS (Channel State Information-Reference Signal) as the path loss estimation signal of the terminal after the RRC connection is established of the terminal. In this case, the base station may transmit information about the transmission power of the CSI-RS to the terminal through the powerControlOffsetSS parameter of the UE dedicated RRC information. In this case, the powerControlOffsetSS may mean a difference (offset) in the transmission power of the SSB and the CSI-RS. In steps 18-30, the terminal can estimate a downlink path attenuation value and set an uplink transmission power value. More specifically, the terminal can measure a downlink RSRP using CSI-RS and estimate a downlink path attenuation value using information about the transmission power of the CSI-RS received from the base station through [Mathematical Formula 17]. Then, based on the estimated path attenuation value, the terminal can set an uplink transmission power value for PUCCH, PUSCH, and SRS transmission. In steps 18-35, the terminal can report a power headroom (PHR) to the base station. The power headroom can mean the difference between the current transmission power of the terminal and the maximum output power of the terminal.In steps 18-40, the base station can optimize system operation based on the reported power headroom. For example, if a specific terminal reports a positive power headroom value to the base station, the base station can allocate more resources (RBs: Resource Blocks) to the terminal to increase system throughput. In steps 18-45, the terminal can receive a transmission power control command (TPC) from the base station. For example, if a specific terminal reports a negative power headroom value to the base station, the base station can allocate fewer resources to the terminal or reduce the transmission power of the terminal through the transmission power control command (TPC). This can increase system throughput or reduce unnecessary power consumption of the terminal. In steps 18-50, the terminal can update the transmission power based on the TPC command. At this time, the TPC command can be transmitted to the terminal through UE-specific DCI or group common DCI. Therefore, the base station can dynamically control the transmission power of the terminal through TPC commands. In steps 18-55, the terminal can perform uplink transmission based on the updated transmission power.

[0561] [PUSCH power control]

[0562] The PUSCH transmission power can be determined through the following [Mathematical Formula 8].

[0563] [Equation 8]

[0564]

[0565] In [Equation 8] is the maximum transmission power set to the terminal for carrier f of serving cell c at PUSCH transmission time point i. is a reference transmission power setting value according to the activated uplink bandwidth part (BWP) b of carrier f of serving cell c, and has different values ​​depending on various transmission types j. It can have different values ​​depending on whether the PUSCH transmission is a message 3 PUSCH for random access, or whether the PUSCH is a configured grant PUSCH, or whether the PUSCH is a scheduled PUSCH. means the frequency size to which PUSCH is allocated. refers to a compensation ratio value for the path loss of UL BWP b of carrier f of serving cell c, and can be set by an upper signal and can have different values ​​depending on j. is a downlink path loss estimation value of UL BWP b of carrier f of serving cell c, and uses a value measured through a reference signal in an activated downlink bandwidth section. The reference signal may be an SS / PBCH block or a CSI-RS. The downlink path loss can be calculated as described in [Mathematical Formula 7]. In another embodiment of the present disclosure, is a downlink path attenuation value, which is the path attenuation calculated by the terminal as in [Mathematical Formula 7]. The terminal calculates the path attenuation based on the reference signal resource linked to the SS / PBCH block or CSI-RS, depending on whether the upper signal is set. The reference signal resource can be selected from among several sets of reference signal resources by the upper signal or L1 signal, and the terminal calculates the path attenuation based on the reference signal resource. is a value determined by the MCS (Modulation and Coding Scheme) value of the PUSCH at the PUSCH transmission time point i of the UL BWP b of the carrier f of the serving cell c. is a power control adaptive value, and the power value can be dynamically adjusted by the TPC command.

[0566] The TPC command is divided into accumulated mode and absolute mode, and one of the two modes is determined by the upper signal. In accumulated mode, the currently determined power control adaptation value is accumulated to the value indicated by the TPC command, and can be increased or decreased depending on the TPC command. have a relationship with is the value indicated by the TPC command. Absolute mode is determined by the TPC command regardless of the currently determined power control adaptation value. . [Table 44] below shows the values ​​that can be specified in the TPC command.

[0567] [Table 44] TPC command

[0568]

[0569] [PUCCH power control]

[0570] The following [Mathematical Formula 9] is a mathematical formula that determines PUCCH transmission power.

[0571] [Equation 9]

[0572]

[0573] In [Equation 9] is the standard setting transmission power setting value, and various transmission types It has different values ​​depending on the MAC CE and the value can be changed by a higher level signal such as RRC or MAC CE. When the value is changed by MAC CE, if the slot in which HARQ-ACK is transmitted for the PDSCH that received MAC CE is k, then k + k offset It is determined that the value is applied from the slot k offset has different values ​​depending on the subcarrier spacing, and can have 3ms as an example. is the size of the frequency resource region to which PUCCH is allocated. is the path attenuation estimation value of the terminal, and as described in [Mathematical Formula 7], the terminal calculates it based on a specific reference signal among various CSI-RS or SS / PBCH depending on whether and what type of upper signal is set. For repetitively transmitted PUCCHs, the same is applied. The same applies to repetitively transmitted PUCCHs. is applied.

[0574] [HARQ-ACK: Type 1 (semi-static) codebook related]

[0575] In a situation where the number of HARQ-ACK PUCCHs that a UE can transmit within a slot is limited to one, when the UE receives a semi-static HARQ-ACK codebook upper configuration, the UE reports HARQ-ACK information for PDSCH reception or SPS PDSCH release within the HARQ-ACK codebook in a slot indicated by the value of the PDSCH-to-HARQ_feedback timing indicator field within DCI format 1_0 or DCI format 1_1. The UE reports the HARQ-ACK information bit value as NACK within the HARQ-ACK codebook in a slot not indicated by the PDSCH-to-HARQ_feedback timing indicator field within DCI format 1_0 or DCI format 1_1. If the terminal reports only one SPS PDSCH release or HARQ-ACK information for one PDSCH reception in MA,C cases for candidate PDSCH reception, and the report is scheduled by DCI format 1_0 including information that the counter DAI (downlink assignment index) field in the Pcell indicates 1, the terminal determines one HARQ-ACK codebook for the corresponding SPS PDSCH release or the corresponding PDSCH reception.

[0576] Other than that, the HARQ-ACK codebook determination method is followed according to the method described below.

[0577] If the set of PDSCH reception candidate cases in serving cell c is MA,c, MA,c can be obtained through the following [pseudo-code 1] steps.

[0578] [Begin pseudo-code 1]

[0579] - Step 1: Initialize j to 0 and MA,c to an empty set. Initialize k, the HARQ-ACK transmission timing index, to 0.

[0580] - 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 above, delete the corresponding row from R.

[0581] - Step 3-1: If the terminal can receive one unicast PDSCH in one slot and R is not an empty set, add one to the set MA,c.

[0582] - 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 add that number to MA,c.

[0583] - Step 4: Increase k by 1 and start again from step 2.

[0584] [End of pseudo-code 1]

[0585] Taking the above-described psudo-code 1 as an example in Fig. 19, in order to perform HARQ-ACK PUCCH transmission in slot#k(1908), all slot candidates for which PDSCH-to-HARQ-ACK timing that can indicate slot#k(1908) is possible are considered. In Fig. 19, it is assumed that HARQ-ACK transmission is possible in slot#k(1908) by PDSCH-to-HARQ-ACK timing combinations that are possible only for PDSCHs scheduled in slot#n(1902), slot#n+1(1904), and slot#n+2(1906). Then, the maximum number of schedulable PDSCHs for each slot is derived by considering the time domain resource configuration information of the schedulable PDSCHs in slots 1902, 1904, and 1906, and the information indicating whether the symbol in the slot is a downlink or an uplink. For example, if two PDSCHs can be scheduled at maximum in slot#n (1902), three PDSCHs can be scheduled at slot#n+1 (1904), and two PDSCHs can be scheduled at slot#n+2 (1906), the maximum number of PDSCHs included in the HARQ-ACK codebook transmitted in slot #k (1908) is seven. This is called the cardinality of the HARQ-ACK codebook.

[0586] Within a specific slot, the above step 3-2 is described through the following [Table 45] (Default PDSCH time domain resource allocation A for normal CP).

[0587] [Table 45]

[0588]

[0589] Table 45 is a time resource allocation table in which a terminal operates by default before receiving time resource allocation through a separate RRC signal. Note that in addition to separately indicating the row index value to RRC, the PDSCH time resource allocation value is determined by the terminal common RRC signal dmrs-TypeA-Position. In Table 45 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.

[0590] 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.

[0591] * 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 45, we can see that row index 14 ends earliest, which is indicated by 1 in the order column. In addition, other row indices that overlap row index 14 by at least one symbol are indicated by 1x in the order column.

[0592] * 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 45, this corresponds to the row with row index 7 and dmrs-TypeA-Position value 3. In addition, other row indices that overlap with this row index by at least one symbol are indicated as 2x in the Order column.

[0593] * Step 3: Repeat Step 2 and display the order value in increasing order. For example, in Table 45, search for the PDSCH allocation value that ends first among the row indices not indicated in the order column. In Table 45, 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.

[0594] * 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.

[0595] In the order column of Table 45, 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 45 means that it exists at 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.

[0596] As another example, considerations for determining a semi-static HARQ-ACK codebook (or type 1 HARQ-ACK codebook) may include:

[0597] a) on a set of slot timing values associated with the active UL BWP

[0598] 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, is provided by the slot timing values ​​{1, 2, 3, 4, 5, 6, 7, 8} for DCI format 1_0

[0599] b) If the UE is configured to monitor PDCCH for DCI format 1_1 for serving cell c, is provided bydl-DataToUL-ACKfor DCI format 1_1

[0600] b) on a set of row indexesRof a table that is provided either by a first set of row indexes of a table that is provided byPDSCH-TimeDomainResourceAllocationListinPDSCH-ConfigCommonor 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 byPDSCH-TimeDomainResourceAllocationListinPDSCH-Config, associated with the active DL BWP and defining respective sets of slot offsets start and length indicatorsSLIV, and PDSCH mapping types for PDSCH reception as described in [6, TS 38.214]

[0601] c) on the ratio between the downlink SCS configuration and the uplink SCS configuration provided bysubcarrierSpacinginBWP-DownlinkandBWP-Uplinkfor the active DL BWP and the active UL BWP, respectively

[0602] d) if provided, onTDD-UL-DL-ConfigurationCommonandTDD-UL-DL-ConfigDedicatedas described in Subclause 11.1.

[0603] 또 다른 일례로, HARQ-ACK 코드북 결정을 위한 pseudo-code는 다음과 같을 수 있다.

[0604] [pseudo-code 2 시작]

[0605] For the set of slot timing values , the UE determines a set of occasions for candidate PDSCH receptions or SPS PDSCH releases according to the following pseudo-code. A location in the Type-1 HARQ-ACK codebook for HARQ-ACK information corresponding to a SPS PDSCH release is same as for a corresponding SPS PDSCH reception.

[0606] Set - index of occasion for candidate PDSCH reception or SPS PDSCH release

[0607] Set

[0608] Set

[0609] Set to the cardinality of set

[0610] Setk=0 - index of slot timing values , in descending order of the slot timing values, in set for serving cell

[0611] while

[0612] if

[0613] Set - index of a DL slot within an UL slot

[0614] while

[0615] Set R to the set of rows

[0616] Set to the cardinality of R

[0617] Set r=0 - index of row in set R

[0618] if slot starts at a same time as or after a slot for an active DL BWP change on serving cell c or an active UL BWP change on the PCell and slot is before the slot for the active DL BWP change on serving cell c or the active UL BWP change on the PCell

[0619] continue;

[0620] else

[0621] while

[0622] if the UE is providedTDD-UL-DL-ConfigurationCommonorTDD-UL-DL-ConfigDedicatedand, for each slot from slot to slot , at least one symbol of the PDSCH time resource derived by row r is configured as ULwhere is thek-th slot timing value in set ,

[0623]

[0624] end if

[0625] r=r+1;

[0626] end while

[0627] if the UE does not indicate a capability to receive more than one unicast PDSCH per slot and ,

[0628]

[0629] j=j+1;

[0630] The UE does not expect to receive SPS PDSCH release and unicast PDSCH in a same slot;

[0631] else

[0632] Set to the cardinality of R

[0633] Set m to the smallest last OFDM symbol index, as determined by theSLIV, among all rows of R

[0634] while

[0635] Set r=0

[0636] while

[0637] if for start OFDM symbol index S for row r

[0638] - index of occasion for candidate PDSCH reception or SPS PDSCH release associated with row r

[0639] R=R / r;

[0640]

[0641] end if

[0642] r=r+1;

[0643] end while

[0644]

[0645] j=j+1;

[0646] Set m to the smallest last OFDM symbol index among all rows of R;

[0647] end while

[0648] end if

[0649] end if

[0650] ;

[0651] end while

[0652] end if

[0653] ;

[0654] end while

[0655] [pseudo-code 2 종료]

[0656] 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 assumed to be mapped 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-ACK timing indicator and PUSCH 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 assumed to be mapped to 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, and the corresponding HARQ-ACK information is determined through a PDSCH-to-HARQ-ACK timing indicator and a PUSCH resource indicator included in the control information indicating the DL SPS release.

[0657] [HARQ-ACK: Type 2 (dynamic) codebook related]

[0658] 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.

[0659] The above DAI is composed of Counter DAI and Total DAI. Counter DAI is information indicating the position of 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 counter DAI in DCI format 1_0 or 1_1 indicates the accumulated value of 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 serving cell where the scheduled DCI exists.

[0660] 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, in a system operating with a single cell, there is no Total DAI parameter.

[0661] An example of the operation of the above DAI is shown in Fig. 20. In Fig. 20, when a terminal transmits a HARQ-ACK codebook selected based on DAI in the nth slot of carrier 0 (2002) on PUCCH (2020) in a situation where 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 occasion set for each carrier are shown. First, the DCI searched at m=0 (2006) indicates that C-DAI and T-DAI each have a value of 1 (2012). The DCI searched at m=1 (2008) indicates that C-DAI and T-DAI each have a value of 2 (2014). The DCI probed on carrier 0 (c=0, 2002) of m=2 (2010) indicates a C-DAI of 3 (2016). The DCI probed on carrier 1 (c=1, 2004) of m=2 (2010) indicates a C-DAI of 4 (2018). In this case, if carriers 0 and 1 are scheduled in the same monitoring occasion, both T-DAIs are indicated as 4.

[0662] In FIGS. 19 and 20, the HARQ-ACK codebook determination operates in a situation where only one PUCCH containing HARQ-ACK information is transmitted within a slot. This is called Mode 1. As an example of how one PUCCH transmission resource is determined within a slot, when PDSCHs scheduled in different DCIs are multiplexed and transmitted as one HARQ-ACK codebook within the same slot, the PUCCH resource selected for HARQ-ACK transmission is determined as the PUCCH resource indicated by the PUCCH resource field indicated in the DCI that last scheduled the PDSCH. That is, the PUCCH resource indicated by the PUCCH resource field indicated in the DCI scheduled before the DCI is ignored.

[0663] The following description defines a method and devices for determining a HARQ-ACK codebook in a situation where two or more PUCCHs containing HARQ-ACK information can be transmitted within a single slot. This is called Mode 2. A terminal may be able to operate only in Mode 1 (only one HARQ-ACK PUCCH is transmitted within a single slot) or only in Mode 2 (one or more HARQ-ACK PUCCHs are transmitted within a single 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 higher-level signaling, or Mode 1 and Mode 2 may be implicitly determined by DCI format, RNTI, DCI-specific field values, scrambling, etc. For example, a PDSCH scheduled with DCI format A and its associated HARQ-ACK information are based on Mode 1, and a 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 the RRC signal.

[0664] [Initial login related]

[0665] Hereinafter, the procedure for a terminal to initially access a cell will be described. FIG. 21 is a diagram illustrating a procedure for transmitting and receiving data between a terminal and a base station for initial access, according to one embodiment. First, before performing the initial access, the terminal receives a PBCH containing a synchronization signal (SS) and a master information block (MIB) from the base station, and then receives a PDSCH containing a system information block (SIB). Through this, the terminal can receive resource areas for performing initial access in the network and sequence information related to the PRACH. Through this, the terminal performs the following series of procedures.

[0666] Msg1 (Preamble Transmission): The UE selects a random access preamble from a set of predefined preambles. These preambles can be roughly divided into two categories: short preambles and long preambles. The UE also selects a random sequence number for the preamble. After selecting the preamble and sequence number, the UE transmits the preamble on the PRACH.

[0667] Receiving Msg2 (Random Access Response): Upon receiving Msg1, the gNB (5G base station) sends a response called Msg2. Msg2 consists of several important pieces of information, including a TA (Time Advance) command for timing adjustment, a RAPID (Random Access Preamble ID) that matches the preamble sent by the UE, and the initial uplink grant for the UE. The gNB also assigns a temporary identifier called RA-RNTI (Random Access Radio Network Temporary Identifier) ​​to the UE. This Msg2 information is transmitted via the PDSCH.

[0668] Transmitting Msg3: The UE transmits Msg3 on the Physical Uplink Shared Channel (PUSCH) using the initial uplink grant provided in Msg2. Msg3 is a PUSCH that can carry a specific RRC message (e.g., RrcRequest) or be pure PHY data.

[0669] Receiving Msg4 (Contention Resolution): After processing Msg3, the gNB transmits Msg4 to the UE. Msg4 is MAC data for Contention Resolution. The Contention Resolution message includes the UE's identity, allowing the gNB to accurately identify the UE and confirm that the contention has been resolved. At this stage, the network provides the UE with a Cell Radio Network Temporary Identifier (C-RNTI). The UE then transmits information on the success or failure of Msg4 reception (or HARQ-ACK feedback) to the base station via the PUCCH. This is called the HARQ PUCCH for the Msg4 PDSCH.

[0670] The above-described procedure is described as a procedure for initial connection, but after initial connection, if a Beam Failure Report (BFR) occurs, or if there is data to be sent to the uplink but there are no SR (Scheduling Request) resources or there is no response from the base station after SR transmission, the terminal may search for the optimal beam again through the above procedure or be able to reallocate uplink resources.

[0671] [Satellite Communication Structure Description]

[0672] The following description describes the characteristics of satellite communication. 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 at an altitude of approximately 36,000 km, MEO refers to a satellite at an altitude of 5,000 to 15,000 km, and LEO refers to a satellite at an altitude of 500 to 1,000 km. Of course, the present invention is not limited to the above examples. According to one embodiment of the present disclosure, the Earth orbital period varies depending on each altitude. For GEO, the Earth orbital period is approximately 24 hours, for MEO, it is approximately 6 hours, and for LEO, it is approximately 90 to 120 minutes. Low Earth orbit (~2,000 km) satellites may have advantages over geostationary (36,000 km) satellites in terms of propagation delay (which can be understood as the time it takes for a signal transmitted from a transmitter to reach a receiver) and loss due to their relatively low altitude. FIG. 22 is a diagram illustrating 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, when 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 when 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 orbiting periodically like a low Earth orbit satellite.

[0673] [Introduction to the Example]

[0674] The above-described initial connection procedure basically operates with a single transmission. However, in cases where the distance between the transmitter and receiver is much longer than that of a terrestrial network, such as a satellite network, it may be difficult for the receiver to receive a signal for initial connection with only a single transmission. Therefore, supporting repeated transmission for each signal for initial connection, as shown in FIG. 23, may be one of the methods for increasing the received signal strength. The following embodiments specifically describe the operation and method for repeated transmission of signals for initial connection. For reference, FIG. 23 illustrates a case where repeated transmissions for all signals transmitted and received for initial connection between a terminal and a base station are allowed, but it may be possible that at least one of these is allowed for repeated transmission, and the rest are performed as single transmissions.

[0675] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the attached drawings. Hereinafter, a base station is an entity that performs resource allocation of a terminal, and may be at least one of a satellite, a gateway, a ground station, a gNode B, a gNB, an eNode B, a Node B, a BS (Base Station), a wireless access unit, a base station controller, or a node on a network. The terminal may include a UE (User Equipment), an MS (Mobile Station), a cellular phone, a smartphone, a computer, or a multimedia system capable of performing a communication function. Although embodiments of the present disclosure are described below using 5G or a next-generation system as an example, 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 communication and mobile communication technologies developed after 5G. Therefore, 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.

[0676] Additionally, when describing the present disclosure, detailed descriptions of related functions or configurations will be omitted if they are deemed to unnecessarily obscure the gist of the present disclosure. Furthermore, the terms described below are defined based on the functions of the present disclosure and may vary depending on the intent or custom of the user or operator. Therefore, their definitions should be based on the contents of this specification.

[0677] In the following description of 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.

[0678] -MIB (Master Information Block)

[0679] -SIB (System Information Block) or SIB

[0680] -RRC (Radio Resource Control)

[0681] -MAC (Medium Access Control) CE (Control Element)

[0682] In addition, L1 signaling may be signaling corresponding to at least one or a combination of one or more signaling methods using the following physical layer channels or signaling.

[0683] -PDCCH (Physical Downlink Control Channel)

[0684] -DCI (Downlink Control Information)

[0685] - UE-specific DCI

[0686] -Group common DCI

[0687] -Common DCI

[0688] -Scheduling DCI (e.g. DCI used for scheduling downlink or uplink data)

[0689] - Non-scheduled DCI (e.g. DCI not intended for scheduling downlink or uplink data)

[0690] -PUCCH (Physical Uplink Control Channel)

[0691] -UCI (Uplink Control Information)

[0692] Additionally, in various embodiments of the present disclosure, the term "terminal" may represent any component such as "user equipment (UE), "mobile station," "subscriber station," "remote terminal," "wireless terminal," "receive point," or "user device." For convenience, the term "terminal" is used in various embodiments of the present disclosure to represent a device that accesses a base station, regardless of whether the terminal is considered a mobile device (such as a mobile phone or a smart phone) or a stationary device (such as a desktop computer or a vending machine).

[0693] Additionally, in various embodiments of the present disclosure, the term “TA” may be used interchangeably with “TA information,” “TA value,” or “TA index.”

[0694] 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.

[0695] 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 associated with 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.

[0696] The following examples describe the processes for repeatedly transmitting and receiving signals required for initial connection when a terminal initially connects to a satellite network. The following items are considered.

[0697] - How to determine the terminal capability (or request) of a satellite (or base station): Terminals within a satellite network may or may not request repeated transmission and reception during initial connection. Alternatively, some terminals may support repeated transmission and reception during the initial connection process, while others may not. Therefore, the satellite must determine this capability during the initial connection process.

[0698] - Terminal capability (or request) reporting method: The terminal may need a judgment condition to request repeated transmission and reception of initial connection-related signals.

[0699] - Method for setting and instructing satellite repeat transmission: If the initially connected terminal supports repeat transmission and reception, the satellite needs to provide scheduling for repeat transmission and reception of signals related to the initial connection.

[0700] - Repeated Transmissions in 2-Step RACH: While repeated transmission and reception may be possible based on the 4-Step RACH, the downside is that this may increase the delay required to complete the initial connection. Therefore, it may be necessary to support repeated transmission and reception of the necessary signals through the 2-Step RACH procedure.

[0701] - Change the basic transmission unit: Usually, the basic unit in which specific signals are transmitted and received during the initial connection process is the slot (or subframe). Instead of supporting repeated transmission, it may be possible to change the standard of the slot.

[0702] The above features are described in detail below.

[0703] [First embodiment]

[0704] The following embodiments describe a method for determining terminal capabilities (or requests) of a satellite (or base station). One of the main characteristics of a satellite network is that the distance between the satellite and the terminal changes dynamically due to various altitudes and variations in elevation angle over time. Therefore, at certain times or in certain environments, the terminal may or may not request repeated transmissions to perform initial access. Since it is more common for the terminal to request repeated transmissions for all signals required for initial access rather than for only a specific signal, the request for repeated transmissions by the terminal may apply to all signals related to the initial access. Therefore, the base station can determine whether or not a terminal that transmitted a PRACH through the resource, which is the very first step of the initial access, requests repeated transmissions during the subsequent initial access process through the PRACH transmission resource. For example, a base station may configure two different PRACH resources, and then set the first PRACH resource as a resource requesting repeated transmission for initial access-related signals, and the second PRACH resource as a resource requesting single transmission for initial access-related signals. In this case, the first PRACH resource may be a single PRACH resource or multiple resources that allow PRACH repeated transmission. If repeated transmission and reception for initial access-related signals are required, the terminal may be able to perform initial access through the first PRACH resource. If repeated transmission and reception for initial access-related signals are not required, the terminal may be able to perform initial access through the second PRACH resource. In summary, the base station may be able to determine whether a terminal that transmitted a PRACH is a terminal that requests repeated transmission and reception for initial access-related signals by configuring different PRACH resources.The first or second PRACH resources described above may not be configured, depending on the base station configuration. Alternatively, the resources may be used only for specific satellite altitudes. For example, the first PRACH resource may be used only when the satellite's elevation angle is 30 degrees or less. The satellite's elevation angle is determined based on the GNSS function installed on the terminal and the satellite's position and orbit information received as a separate upper layer signal. As another example, the use of the second PRACH resource may not be permitted when the satellite's elevation angle is 30 degrees or less.

[0705] Alternatively, since satellite networks typically have significantly longer distances between transmitters and receivers than terrestrial networks, it may be possible to always allow repeated transmissions during initial access. Therefore, it may be possible to determine whether or not a specific base station supports repeated transmissions for initial access-related signals, depending on whether the environment in which the base station operates is a satellite network or a terrestrial network. For example, if the area served by a base station is served via a satellite network, or if the frequency served by the base station is a satellite network-only frequency, the base station may be able to provide resources for repeated transmissions, starting with PRACH resources, without separate terminal capabilities (or requests). In other words, the base station may only provide the first PRACH resource area in which PRACH repeated transmissions are possible.

[0706] [Second Embodiment]

[0707] In the following embodiments, when the base station distinguishes separate PRACH resources to distinguish the terminal's capability (or request) for repeated transmission and reception related to initial access, the terminal needs to determine which resource to select. The terminal may be able to consider at least one of the following methods, or a combination thereof. For convenience of explanation, the first PRACH resource is considered as a resource used by the terminal to request repeated transmission and reception of initial access-related signals, and the second PRACH resource is considered as a resource used by the terminal to request single transmission and reception of initial access-related signals.

[0708] - Method 2-1: Based on the SSB reception signal strength, the terminal determines whether to select the first PRACH resource or the second PRACH resource. For example, the base station provides threshold information related to the SSB reception signal strength as an upper signal, and the terminal determines whether the measured SSB signal strength is greater than or less than the threshold information. If the SSB measurement signal strength is lower than the threshold, the terminal may select the first PRACH resource, and if the SSB measurement signal strength is greater than the threshold, the terminal may select the second PRACH resource. The fact that the SSB measurement signal strength is lower than the threshold may mean that the received signal strength of the corresponding SSB is low, and thus repeated transmission and reception may be required. Accordingly, the base station can determine whether the terminal requests repeated transmission and reception or single transmission and reception for initial access related signals, depending on whether the terminal selects the first PRACH resource or the second PRACH resource for transmission. The above threshold value can have multiple values, and accordingly, two or more PRACH resources can be set. In addition to distinguishing between single transmission and repeated transmission, each PRACH resource can be utilized to indicate the number of times or range of repeated transmissions. For example, if two threshold values ​​are set, a total of three PRACH resources may be provided. In addition, each PRACH resource may be utilized as a resource requesting a single transmission, 2 to 4 repeated transmissions, and 5 to 16 repeated transmissions, respectively.

[0709] - Method 2-2: Generally, as the distance between the transmitter and receiver increases, the received power tends to decrease inversely proportional to the distance under the assumption of the same transmission power. In addition, artificial satellites can be located at various altitudes, and the distance between the terminal and the satellite varies depending on the altitude angle. Therefore, if the terminal is equipped with a GNSS function, it can determine its own position, and if it can receive satellite position information through a separate upper signal, it may be possible to determine the distance between the satellite and the terminal before the initial connection. Accordingly, depending on the distance between the satellite and the terminal, the terminal may be able to determine whether to select the first PRACH resource or the second PRACH resource to perform the initial connection. Alternatively, the satellite may provide a threshold related to the distance between the satellite and the terminal for determining whether to select the first PRACH resource or the second PRACH resource through a separate upper signal. The unit of the threshold is distance, and if the distance between the satellite and the terminal determined by the terminal is greater than the threshold, the terminal may be able to select the first PRACH resource and transmit the PRACH. If the distance between the satellite and the terminal determined by the terminal is less than a threshold value, the terminal may be able to select a second PRACH resource and transmit a PRACH. The unit of the threshold value may be m, km, etc.

[0710] - Method 2-3: Methods 2-1 and 2-2 are methods in which a terminal receives an SSB signal or location information from a satellite and, based on this, requests repeated transmission and reception of signals related to the terminal's initial access using a specific PRACH resource. In contrast, Method 2-3 may be a method that allows the base station to unconditionally request repeated transmission and reception or unconditionally request a single transmission and reception without performing Methods 2-1 and 2-2 under certain conditions, since the base station can independently calculate the area it is servicing and the satellite's altitude or distance information. Accordingly, the satellite may be able to provide the terminal with information related to a specific time period through a higher-order signal. In addition, if the terminal is within the specific period when performing the initial access, the terminal may be able to always select the first PRACH resource or the second PRACH resource without performing a separate judgment procedure such as Method 2-1 or Method 2-2. In this way, the PRACH resource to be selected in the corresponding period may also be provided as a separate higher-order signal.

[0711] - Method 2-4: The above-described methods may additionally be applied only to satellite networks. That is, the above-described methods do not apply to terrestrial networks, and it may be possible to transmit and receive initial access-related signals based on a single transmission / reception basis. To this end, the terminal may determine whether the network is a satellite or terrestrial network based on the frequency resource on which the terminal performs the initial access, if the frequency resources for the satellite or terrestrial network are distinct. Alternatively, if a specific area is serviced only by satellite or terrestrial networks and the terminal knows this information in advance, the terminal may be able to determine its location information through GNSS information before the initial access. Therefore, it may be possible to determine whether the network performing the initial access at the location identified by the terminal is a terrestrial or satellite network using GNSS information. Alternatively, it may be possible for the terminal to determine whether the network from which the SS / PBCH is received is a satellite or terrestrial network through a separate SIB. That is, when a terminal receives a synchronization signal and system information, it may be possible to utilize specific fields within the system information to indicate whether or not the system information includes satellite network-specific information. Accordingly, if the information is included, it may be possible to determine that the system information is a satellite network, and if not, it may be a terrestrial network.

[0712] [Third Embodiment]

[0713] The following embodiments describe a method in which a satellite (or base station) supports repeated transmission of signals related to initial access to a terminal that has requested repeated transmission through a previous embodiment. The satellite may be able to provide the terminal with one or more values ​​indicating repeated transmission / reception through an SIB. These values ​​may be applicable only to specific signals related to initial access or to all signals. For example, if a repeated transmission / reception value of 2 is provided through an SIB, the terminal may determine that the repeated transmission / reception values ​​for all of msg1, msg2, msg3, msg4, and the PUCCH containing HARQ-ACK information for msg4 are set to 2. Alternatively, one or more specific values ​​may be set for each signal. If only one value is set, it may be considered that the value is always applied when performing an initial access. If multiple values ​​are set, one value may be applied through DCI or MAC CE. For example, if the repetition transmission value for msg2 PDSCH is set to 2, 4, it may be possible for a specific field consisting of 1 bit in the DCI that schedules msg2 PDSCH to indicate the msg2 PDSCH repetition transmission value. Alternatively, it may be possible for the repetition transmission of each initial access related signal to be implicitly linked and applied. For example, if {number of msg2 repetitions, number of msg3 repetitions, number of msg4 repetitions, number of PUCCH repetitions of msg4} are configured as two sets of {2, 4, 2, 6} and {1, 2, 1, 4} and are set as upper signals, it may be possible for the repetition transmission counts for subsequent initial access related signals to be determined according to the finally selected number of msg2 repetitions.For example, if the number of repetitions of msg2 is determined to be 2, the number of repetitions of msg3, the number of repetitions of msg4, and the number of PUCCH repetitions of msg4 may be implicitly determined to be 4, 2, and 6, respectively. As another example, if the number of repetitions of msg2 is determined to be 1, the number of repetitions of msg3, the number of repetitions of msg4, and the number of PUCCH repetitions of msg4 may be implicitly determined to be 2, 1, and 4, respectively. This method can provide multiple repetition counts for the number of repetitions of msg3, the number of repetitions of msg4, and the number of PUCCH repetitions of msg4, and its main feature is that the number of repetitions of msg2 is dynamically selected without a separate bit field indicating the number of repetitions when scheduling each signal. Alternatively, multiple repeat transmission counts may be set, but the actual values ​​applied to the actual repeat transmissions may be implicitly determined instead of through explicit signals such as DCI or MAC CE. An example of implicit determination may be based on the distance between the satellite and the terminal. That is, the satellite provides a threshold related to the distance between the terminal and the satellite in addition to the multiple repeat transmission counts. The terminal may then determine whether to apply the first or second value among the multiple repeat transmission counts, depending on whether the threshold is greater or less than the threshold. Alternatively, the situation in which the repeat transmissions are applied has been described with respect to initial connection-related signals, but is not limited thereto, and may be extended to apply to uplink or downlink data channels or control channels in connected mode after the initial connection. For example, if the number of repeat transmissions applied to the uplink control channel during the initial connection is 4, the number of repeat transmissions applied by the terminal when transmitting the uplink control channel in connected mode after the initial connection is completed may be determined to be 4.It may be possible to apply this approach similarly to other channels.

[0714] [Example 4]

[0715] Hereinafter, the description will explain the method of performing repeated transmission in a situation where 2-step RA (Random Access) is applied. Basically, 2-step RA has the advantage of being able to complete the initial connection more quickly because the number of signals required for the initial connection is small. However, in order to apply this to a satellite network, Msg A and Msg B applied to 2-step RA have larger payload sizes than Msg 1, 2, 3, and 4, so they may require a larger number of repeated transmissions than Msg 1, 2, 3, and 4. However, if Msg A and Msg B are each repeatedly transmitted 6 times rather than repeatedly transmitting Msg 1, 2, 3, and 4 4 times each, it is advantageous from the perspective of increasing the efficiency of radio resource use to support the total number of repeated transmissions by utilizing 2-step RA. Therefore, it may be possible to consider 2-step RA in a satellite network by supporting repeated transmissions for Msg A and Msg B. To this end, the base station may be able to provide, through higher-level signals, whether the terminal will perform the initial connection using 2-step RA or 4-step RA. For example, if the base station provides only 2-step RA resources, the terminal may be able to perform the initial connection using the 2-step RA method. If the base station provides only 4-step RA resources, the terminal may be able to perform the initial connection using the 4-step RA method. If the base station provides both 2-step RA and 4-step RA resources, the terminal may be able to determine whether to perform the initial connection using the 2-step RA resources or the 4-step RA resources by judging specific conditions. For example, the terminal may be able to calculate the distance between the terminal and the satellite, and if the calculated distance is greater than a specific threshold set as a separate higher-level signal, it may be able to perform the initial connection using the 4-step RA resources.The terminal may be able to perform an initial connection through a 2-step RA resource if the calculated distance between the terminal and the satellite is less than a specific threshold set as a separate upper signal. Alternatively, the reverse may be applied. As another example, the terminal may be able to perform an initial connection through a 2-step RA resource if the received signal strength of the SSB received from the satellite is greater than a specific threshold set as a separate upper signal. The terminal may be able to perform an initial connection through a 4-step RA resource if the received signal strength of the SSB received from the satellite is less than a specific threshold set as a separate upper signal. Alternatively, the reverse may be applied. As another example, the terminal may be able to perform an initial connection through a 4-step RA resource if the calculated distance between the terminal and the satellite is greater than a specific threshold set as a separate upper signal. The terminal may be able to perform an initial connection through a 2-step RA resource if the calculated distance between the terminal and the satellite is less than a specific threshold set as a separate upper signal. Alternatively, the reverse may be applied. As another example, a terminal may be able to perform an initial connection via a 4-step RA resource if the time of initial connection falls within a specific time interval set by a separate higher-level signal. If the time of initial connection does not fall within a specific time interval set by a separate higher-level signal, the terminal may be able to perform an initial connection via a 2-step RA resource. Alternatively, the reverse may apply.

[0716] [Example 5]

[0717] The previously described embodiments primarily describe methods for scheduling repeated transmission and reception of initial access-related signals from a satellite (or base station) to a terminal during the initial access process. The reason for this repeated transmission and reception is that, since the length of one slot is 1 ms at 15 kHz, it may be necessary to support repeated transmission and reception using multiple slots to increase the received signal strength at the receiver. Instead of supporting such repeated transmission and reception, it may be possible to consider a method in which the basic transmission unit for transmitting and receiving not only the initial access signal but also all signals after connection mode is set to multiple slots rather than one slot in a satellite communication network. For example, the basic transmission unit for receiving a PDSCH or transmitting a PUSCH may consist of four slots rather than one slot. Therefore, from a time resource perspective, the received signal strength at the receiver can be increased due to the increased length of the basic transmission unit, which can be utilized instead of a method supporting repeated transmission and reception. The above basic transmission unit is provided through an upper signal, and may be applied regardless of each physical channel, or different values ​​may be applied to each physical channel. For example, it may be possible for both PUCCH / PDSCH / PDSCH to have a basic transmission unit of 4 slots. Alternatively, it may be possible for the number of symbols included in 1 slot to be set to a value corresponding to a multiple of 12 or 14 symbols, regardless of the physical channel. For example, it may be possible for 1 slot to have a number of symbols consisting of 28. Alternatively, the basic transmission unit may be implicitly determined according to the satellite altitude, or may vary depending on the distance between the satellite and the terminal.For example, if the satellite altitude (or the distance between the satellite and the terminal) is 10,000 km, 1 slot may be determined to have a symbol count of 56, and if the satellite altitude (or the distance between the satellite and the terminal) is 700 km, 1 slot may be determined to have a symbol count of 28. Alternatively, when transmitting PRACH, the size of the used repetitive transmission resource may be determined as the basic transmission unit. For example, if the length of the PRACH transmission resource set by the satellite is 2 ms, the terminal may be able to determine that length to be determined as 1 slot.

[0718] FIG. 24 is a flowchart illustrating a process for repeated transmission and reception when a terminal makes an initial connection in a satellite network according to an embodiment of the present disclosure. The terminal first receives a synchronization signal and system information to perform an initial connection. The system information receives initial connection-related information. The system-related information may correspond to one or a combination of the information described in Embodiments 1 to 5. Thereafter, the terminal may report its capabilities or request for initial connection-related signals through the initial connection. The terminal capability reporting or request reporting method may correspond to one or a combination of Embodiments 1 and 2. Thereafter, the terminal receives scheduling information for initial connection-related signals, and transmits and receives the initial connection-related signals accordingly. The method for this may correspond to one or a combination of the methods described in Embodiment 3.

[0719] FIG. 25 is a block diagram illustrating the internal structure of a satellite according to an embodiment of the present disclosure. As illustrated in FIG. 25, the satellite of the present disclosure may include a satellite receiver (2500), a satellite transmitter (2520), and a satellite processor (2510). The receiver, transmitter, and processor may be configured in multiple units. That is, the satellite may be configured with a receiver and transmitter for transmitting and receiving signals from a terminal, a receiver and transmitter for transmitting and receiving signals from a base station, and a receiver and transmitter for transmitting and receiving signals with other satellites. The satellite receiver (2500) and the satellite transmitter (2520) may be collectively referred to as a satellite transceiver in the embodiment of the present disclosure. The transceiver may transmit and receive signals with a terminal and a base station. 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, an RF receiver that low-noise-amplifies the received signal, and down-converts the frequency. In addition, the transceiver may receive a signal through a wireless channel and output it to a satellite processing unit (2510), and transmit a signal output from the satellite processing unit (2510) through the wireless channel. The satellite processing unit (2510) may include a compensator (pre-compensator) for correcting a frequency offset or a Doppler shift, and may include a device capable of tracking a location from a GPS, etc. In addition, the satellite processing unit (2510) may include a frequency shift function capable of shifting the center frequency of the received signal. The satellite processing unit (2510) may control a series of processes so that a satellite, a base station, and a terminal can operate according to the above-described embodiment of the present disclosure. For example, a satellite receiver (2500) may receive a PRACH preamble from a terminal, transmit the corresponding RAR back to the terminal, and decide to transmit TA information to the base station.Afterwards, the satellite transmitter (2520) can transmit the corresponding signals at a determined time.

[0720] FIG. 26 is a diagram illustrating the structure of a terminal in a wireless communication system according to an embodiment of the present disclosure.

[0721] Referring to FIG. 26, the terminal may include a transceiver, which refers to a terminal receiving unit (2600) and a terminal transmitting unit (2610), a memory (not shown), and a terminal processing unit (2605, or a terminal control unit or processor). Depending on the communication method of the terminal described above, the transceiver units (2600, 2610), the memory, and the terminal processing unit (2605) 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.

[0722] 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.

[0723] 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.

[0724] 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.

[0725] 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 control components of the terminal so that initial access-related signals of the terminal are repeatedly transmitted and received via the first PRACH resource. There may be multiple processors, and the processors can perform component control operations of the terminal by executing programs stored in memory.

[0726] FIG. 27 is a diagram illustrating the structure of a base station in a wireless communication system according to an embodiment of the present disclosure.

[0727] Referring to FIG. 27, the base station may include a transceiver, which refers to a base station receiver (2700) and a base station transmitter (2710), a memory (not shown), and a base station processing unit (2705, or a base station control unit or processor). Depending on the communication method of the base station described above, the transceiver units (2700, 2710), the memory, and the base station processing unit (2705) 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.

[0728] 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.

[0729] 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.

[0730] 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.

[0731] The processor may control a series of processes so that the base station can operate according to the aforementioned embodiments of the present disclosure. For example, the processor may provide configuration information for determining resources through which signals related to the initial access of a terminal are transmitted and received, and may control each component of the base station so that the signals related to the initial access of the terminal are transmitted and received through the configured PRACH resources. There may be multiple processors, and the processors may perform component control operations of the base station by executing programs stored in memory.

[0732] 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.

[0733] 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.

[0734] 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.

[0735] 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.

[0736] 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.

[0737] Meanwhile, the embodiments of the present disclosure disclosed in this specification and drawings are only specific examples to easily explain the technical contents of the present disclosure and 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 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 parts of another embodiment can be combined with each other to operate a satellite, 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 satellite, a base station, and a terminal. In addition, although the above-mentioned embodiments have been presented based on an FDD LTE system, other modifications based on the technical idea of ​​the above-mentioned embodiments can be implemented with other systems such as a TDD LTE system, a 5G, or a NR system.

[0738] Meanwhile, the order of description in the drawings explaining the method of the present disclosure does not necessarily correspond to the order of execution, and the order of precedence may be changed or executed in parallel.

[0739] Alternatively, the drawings illustrating the method of the present disclosure may omit some components and include only some components without detracting from the essence of the present disclosure.

[0740] In addition, the method of the present disclosure 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.

[0741] 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. In a method for a terminal to perform communication with a satellite in a wireless communication system, A step of receiving configuration information regarding initial access related signals from the satellite, wherein the configuration information includes a first PRACH (physical random access channel) resource associated with repeated transmission and reception of the initial access related signals and a second PRACH resource associated with single transmission and reception of the initial access related signals; A step of selecting one of the first PRACH resource and the second PRACH resource based on whether the initial access related signal is repeatedly transmitted and received; A step of performing repeated transmission and reception of initial access related signals with the satellite when a random access preamble is transmitted to the satellite using the first PRACH resource according to selection of the first PRACH resource; and A method comprising the step of performing a single transmission and reception of the initial access related signals with the satellite when the random access preamble is transmitted to the satellite using the second PRACH resource according to the selection of the second PRACH resource.

2. In the first paragraph, the step of selecting one of the first PRACH resource and the second PRACH resource is: A method for selecting one of the first PRACH resource and the second PRACH resource by using the reception signal strength of the SSB received from the satellite, the distance between the satellite and the terminal, or the time interval information set from the satellite.

3. In the second paragraph, the setting information regarding the initial connection related signals is: Contains at least one of a received signal strength threshold, a distance threshold, and the above time interval information, If the received signal strength of the received SSB is lower than the received signal strength threshold, the first PRACH resource is selected, If the distance between the satellite and the terminal is further than the distance threshold, the first PRACH resource is selected, A method wherein the above time period information indicates a time period during which each of the first PRACH resource and the second PRACH resource is selected.

4. In paragraph 1, the setting information regarding the initial connection related signals is: A method including information indicating the number of times the initial connection-related signals are repeatedly transmitted and received.

5. In paragraph 4, A method further comprising a step of selecting one of the plurality of numbers by using at least one of the MAC CE (medium access control-control element) or DCI (downlink control information) received from the satellite, when the number of the initial connection-related signals to be repeatedly transmitted and received is plural in the setting information regarding the initial connection-related signals.

6. In paragraph 1, A method further comprising a step of identifying whether to perform 2-step RA (random access) or 4-step RA for initial connection to the satellite based on setting information regarding the initial connection-related signals, distance between the terminal and the satellite, or preset time interval information.

7. In a terminal that performs communication with a satellite in a wireless communication system, Transmitter and receiver; and At least one processor connected to the transceiver, wherein the at least one processor: Receive configuration information about initial access related signals from the satellite, wherein the configuration information includes a first PRACH (physical random access channel) resource associated with repeated transmission and reception of the initial access related signals and a second PRACH resource associated with single transmission and reception of the initial access related signals, Based on whether the initial access-related signal is repeatedly transmitted and received, one of the first PRACH resource and the second PRACH resource is selected, According to the selection of the first PRACH resource, when a random access preamble is transmitted to the satellite using the first PRACH resource, repeated transmission and reception of the initial access related signals with the satellite are performed, A terminal that performs single transmission and reception of initial access related signals with the satellite when the random access preamble is transmitted to the satellite using the second PRACH resource according to the selection of the second PRACH resource.

8. In the 7th paragraph, the at least one processor, A terminal that selects one of the first PRACH resource and the second PRACH resource by using the reception signal strength of the SSB received from the satellite, the distance between the satellite and the terminal, or the time interval information set from the satellite.

9. In paragraph 8, the setting information regarding the initial connection related signals is: Contains at least one of a received signal strength threshold, a distance threshold, and the above time interval information, If the received signal strength of the received SSB is lower than the received signal strength threshold, the first PRACH resource is selected, If the distance between the satellite and the terminal is further than the distance threshold, the first PRACH resource is selected, The above time period information indicates a time period during which each of the first PRACH resource and the second PRACH resource is selected.

10. In paragraph 7, the setting information regarding the initial connection related signals is: A terminal including information indicating the number of times the initial connection-related signals are repeatedly transmitted and received.

11. In the 10th paragraph, the at least one processor, A terminal that selects one of the plurality of numbers by using at least one of the MAC CE (medium access control-control element) or DCI (downlink control information) received from the satellite when the number of the initial connection-related signals included in the setting information regarding the initial connection-related signals is plural.

12. In the 7th paragraph, the at least one processor, A terminal that identifies whether to perform 2-step RA (random access) or 4-step RA for initial connection to the satellite based on setting information regarding the initial connection-related signals, distance between the terminal and the satellite, or preset time interval information.

13. In a method for a satellite to perform communication with a terminal in a wireless communication system, A step of transmitting configuration information regarding initial access related signals to the terminal, wherein the configuration information includes a first PRACH (physical random access channel) resource associated with repeated transmission and reception of the initial access related signals and a second PRACH resource associated with single transmission and reception of the initial access related signals; When the first PRACH resource is selected from the terminal, a step of performing repeated transmission and reception of initial access related signals with the terminal when a random access preamble is received from the terminal using the first PRACH resource; and A method comprising: performing a single transmission and reception of initial access related signals with the terminal when the random access preamble is received from the terminal using the second PRACH resource, as the second PRACH resource is selected from the terminal.

14. In paragraph 13, A method in which one of the first PRACH resource and the second PRACH resource is selected using the reception signal strength of the SSB received from the satellite to the terminal, the distance between the satellite and the terminal, or the time interval information set from the satellite.

15. In a satellite that performs communication with a terminal in a wireless communication system, Transmitter and receiver; and At least one processor connected to the transceiver, wherein the at least one processor: Transmitting configuration information regarding initial access related signals to the terminal, wherein the configuration information includes a first PRACH (physical random access channel) resource associated with repeated transmission and reception of the initial access related signals and a second PRACH resource associated with single transmission and reception of the initial access related signals, When the first PRACH resource is selected from the terminal, and a random access preamble is received from the terminal using the first PRACH resource, repeated transmission and reception of initial access related signals are performed with the terminal, A satellite that performs single transmission and reception of initial access related signals with the terminal when the random access preamble is received from the terminal using the second PRACH resource as the second PRACH resource is selected from the terminal.

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