Method and device for recovering beam failure in network cooperative communication

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting higher data transmission rates. A method performed by a terminal in a communication system according to an embodiment of the present disclosure may comprise the steps of: receiving, from a base station, information about a bandwidth part (BWP) including one or more transmission configuration indication (TCI) state configurations; calculating a first path loss value on the basis of a first reference signal or a second reference signal; identifying transmission power of an uplink signal on the basis of the first path loss value; and transmitting the uplink signal to the base station on the basis of the transmission power. Whether to receive the first reference signal may be determined according to whether at least one TCI state configuration among the one or more TCI state configurations includes a pathloss offset.

Description

Method and device for recovering beam failure in network cooperative communication

[0001] The present disclosure relates to the operation of a terminal and a base station in a wireless communication system. Specifically, the present disclosure relates to a beam failure recovery method in network cooperative communication and a device capable of performing the same.

[0002] 5G mobile communication technology defines a wide frequency band to enable fast transmission speeds and new services, and can be implemented not only in the sub-6GHz frequency band such as 3.5 gigahertz (3.5GHz), but also in the ultra-high frequency band called millimeter wave (mmWave) such as 28GHz and 39GHz ('Above 6GHz'). In addition, for 6G mobile communication technology, which is called the system after 5G communication (Beyond 5G), implementation in the terahertz band (for example, the 3 terahertz (3THz) band at 95GHz) is being considered to achieve a transmission speed that is 50 times faster than 5G mobile communication technology and an ultra-low latency time that is reduced to one-tenth.

[0003] In the early stages of 5G mobile communication technology, the goal is to support services and satisfy performance requirements for enhanced Mobile Broadband (eMBB), Ultra-Reliable Low-Latency Communications (URLLC), and massive Machine-Type Communications (mMTC). These include beamforming and massive MIMO to mitigate path loss of radio waves in ultra-high frequency bands and increase the transmission distance of radio waves, support for various numerologies (such as operation of multiple subcarrier intervals) and dynamic operation of slot formats for efficient use of ultra-high frequency resources, initial access technology to support multi-beam transmission and wideband, definition and operation of BWP (Bidth Part), new channel coding methods such as LDPC (Low Density Parity Check) codes for large-capacity data transmission and Polar Code for reliable transmission of control information, and L2 pre-processing (L2). Standardization has been made for network slicing, which provides dedicated networks specialized for specific services, and pre-processing.

[0004] Currently, discussions are underway to improve and enhance the initial 5G mobile communication technology in consideration of the services that 5G mobile communication technology was intended to support, and physical layer standardization is in progress for technologies such as V2X (Vehicle-to-Everything) to help autonomous vehicles make driving decisions and increase user convenience based on their own location and status information transmitted by vehicles, NR-U (New Radio Unlicensed) for the purpose of system operation that complies with various regulatory requirements in unlicensed bands, NR terminal low power consumption technology (UE Power Saving), Non-Terrestrial Network (NTN), which is direct terminal-satellite communication to secure coverage in areas where communication with terrestrial networks is impossible, and Positioning.

[0005] In addition, standardization of wireless interface architecture / protocols is in progress for technologies such as intelligent factories (Industrial Internet of Things, IIoT) to support new services through linkage and convergence with other industries, Integrated Access and Backhaul (IAB) that provides nodes for expanding network service areas by integrating wireless backhaul links and access links, Mobility Enhancement technology including Conditional Handover and Dual Active Protocol Stack (DAPS) handover, and 2-step random access (2-step RACH for NR) that simplifies random access procedures. Standardization is also in progress for system architecture / services such as 5G baseline architecture (e.g., Service-based Architecture, Service-based Interface) for grafting Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) technologies, and Mobile Edge Computing (MEC) that provides services based on the location of the terminal.

[0006] Once these 5G mobile communication systems are commercialized, an explosive increase in connected devices will be connected to the communication network, necessitating enhanced functionality and performance of 5G mobile communication systems and integrated operation of these connected devices. To this end, new research will be conducted on improving 5G performance and reducing complexity, supporting AI services, supporting metaverse services, and drone communications by utilizing eXtended Reality (XR), Artificial Intelligence (AI), and Machine Learning (ML) to efficiently support Augmented Reality (AR), Virtual Reality (VR), and Mixed Reality (MR).

[0007] In addition, the development of these 5G mobile communication systems includes new waveforms to ensure coverage in the terahertz band of 6G mobile communication technology, multi-antenna transmission technologies such as Full Dimensional MIMO (FD-MIMO), Array Antenna, and Large Scale Antenna, metamaterial-based lenses and antennas to improve the coverage of terahertz band signals, high-dimensional spatial multiplexing technology using Orbital Angular Momentum (OAM), Reconfigurable Intelligent Surface (RIS) technology, as well as full duplex technology to improve the frequency efficiency and system network of 6G mobile communication technology, satellite, AI (Artificial Intelligence) from the design stage and AI-based communication technology that realizes system optimization by internalizing end-to-end AI support functions, and ultra-high-performance communication and computing resources to provide services with complexity that exceeds the limits of terminal computing capabilities. It can serve as a basis for the development of next-generation distributed computing technologies that can be realized by utilizing them.

[0008] The disclosed embodiment seeks to provide a device and method capable of effectively providing a service in a mobile communication system.

[0009] A method performed by a terminal of a communication system according to one embodiment of the present disclosure may include the steps of receiving information about a bandwidth part (BWP) including one or more transmission configuration indication (TCI) state settings from a base station, calculating a first pathloss value based on a first reference signal or a second reference signal, identifying a transmission power of an uplink signal based on the first pathloss value, and transmitting the uplink signal to the base station based on the transmission power. Whether the first reference signal is received may be determined based on whether at least one TCI state setting among the one or more TCI state settings includes a pathloss offset.

[0010] A method performed by a base station of a communication system according to one embodiment of the present disclosure may include the steps of transmitting information about a bandwidth part (BWP) including one or more transmission configuration indication (TCI) state settings to a terminal, and receiving an uplink signal from the terminal based on a transmission power associated with a first pathloss value. The first pathloss value may be based on a first reference signal or a second reference signal, and whether or not to transmit the first reference signal may be determined based on whether at least one of the one or more TCI state settings includes a pathloss offset.

[0011] According to one embodiment of the present disclosure, a terminal of a communication system may include at least one transceiver, at least one processor communicatively connected to the at least one transceiver, and a memory communicatively connected to the at least one processor and executable by the at least one processor individually or in any combination, wherein the at least one processor stores instructions that cause the terminal to receive information about a bandwidth part (BWP) including one or more transmission configuration indication (TCI) state settings from a base station, calculate a first path loss value based on a first reference signal or a second reference signal, identify a transmission power of an uplink signal based on the first path loss value, and transmit the uplink signal to the base station based on the transmission power. Whether the first reference signal is received may be determined based on whether at least one TCI state setting among the one or more TCI state settings includes a path loss offset.

[0012] In one embodiment of the present disclosure, a base station of a communication system may include at least one transceiver, at least one processor communicatively connected to the at least one transceiver, and a memory communicatively connected to the at least one processor and executable by the at least one processor individually or in any combination, the memory storing instructions that cause the base station to transmit information about a bandwidth part (BWP) including one or more transmission configuration indication (TCI) state settings to a terminal and to receive an uplink signal from the terminal based on a transmission power associated with a first pathloss value. The first pathloss value may be based on a first reference signal or a second reference signal, and whether or not to transmit the first reference signal may be determined based on whether at least one of the one or more TCI state settings includes a pathloss offset.

[0013] The disclosed embodiment provides a device and method capable of effectively providing a service in a mobile communication system.

[0014] 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.

[0015] 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.

[0016] 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.

[0017] FIG. 4 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.

[0018] FIG. 5 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.

[0019] FIG. 6 is a diagram illustrating the structure of a downlink control channel in a wireless communication system according to one embodiment of the present disclosure.

[0020] Figure 7a illustrates a process for beam setting and activation of PDSCH.

[0021] Figure 7b illustrates a process for beam setting and activation of PDSCH.

[0022] FIG. 8 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.

[0023] FIG. 9 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.

[0024] Fig. 10 is a diagram showing an Enhanced PDSCH TCI state activation / deactivation MAC-CE structure.

[0025] FIG. 11 is a diagram illustrating another MAC-CE structure for activating and indicating a joint TCI state or a separate DL or UL TCI state in a wireless communication system according to an embodiment of the present disclosure.

[0026] FIG. 12 is a diagram of a beam application time that can be considered when using an integrated TCI method in a wireless communication system according to an embodiment of the present disclosure.

[0027] FIG. 13 is a diagram illustrating a process of a base station responding to a BFR request signal of a terminal during PCell BFR operation according to an embodiment of the present disclosure.

[0028] FIG. 14 is a diagram illustrating a process of a base station responding to a BFR request signal of a terminal during SCell BFR operation according to an embodiment of the present disclosure.

[0029] FIG. 15a is a diagram showing the structure of a BFR MAC-CE according to an embodiment of the present disclosure.

[0030] FIG. 15b is a diagram showing the structure of a BFR MAC-CE according to an embodiment of the present disclosure.

[0031] FIG. 16 is a diagram illustrating a process of a base station responding to a BFR request signal of a terminal when BFR operation is performed by TRP according to an embodiment of the present disclosure.

[0032] FIG. 17a is a diagram illustrating the structure of an enhanced BFR MAC-CE according to an embodiment of the present disclosure.

[0033] FIG. 17b is a diagram illustrating the structure of an enhanced BFR MAC-CE according to an embodiment of the present disclosure.

[0034] FIG. 18 is a diagram illustrating an example of the operation of a base station and a terminal operating in multiple TRPs, including a TRP that supports only an uplink reception function according to one embodiment of the present disclosure.

[0035] FIG. 19 is a diagram illustrating a method for calculating and updating a path loss difference value according to one embodiment of the present disclosure.

[0036] FIG. 20 is a diagram illustrating another method for calculating and updating a path loss difference value according to one embodiment of the present disclosure.

[0037] FIG. 21 is a diagram illustrating the operation of a terminal for determining an uplink transmission method according to one embodiment of the present disclosure.

[0038] FIG. 22 is a diagram illustrating the operation of a base station for determining an uplink transmission method according to one embodiment of the present disclosure.

[0039] FIG. 23 is a diagram illustrating the structure of a terminal in a wireless communication system according to an embodiment of the present disclosure.

[0040] FIG. 24 is a diagram illustrating the structure of a base station in a wireless communication system according to an embodiment of the present disclosure.

[0041] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the attached drawings.

[0042] In describing the embodiments, descriptions of technical details that are well known in the technical field to which the present disclosure pertains and are not directly related to the present disclosure will be omitted. This is to ensure that the gist of the present disclosure is conveyed more clearly without obscuring it by omitting unnecessary explanations.

[0043] 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.

[0044] 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 these may vary depending on the intention or custom of the user or operator. Therefore, their definitions should be made based on the contents throughout the specification.

[0045] 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 with some modifications within a scope that does not significantly deviate from the scope of the present disclosure, as judged by a person having skilled technical knowledge.

[0046] 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).

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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).

[0052] 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.

[0053] 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.

[0054] Finally, URLLC refers to a cellular-based wireless communication service used for a specific purpose (mission-critical). For example, services such as remote control of robots or machinery, industrial automation, unmanned aerial vehicles, remote health care, and emergency alerts can be considered. Therefore, the communication provided by URLLC must provide very low latency and very high reliability. For example, a service supporting URLLC must satisfy an air interface latency of less than 0.5 milliseconds and, at the same time, 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.

[0055] 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.

[0056] [NR time-frequency resources]

[0057] Below, the frame structure of the 5G system is described in more detail with reference to drawings.

[0058] 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.

[0059] The horizontal axis of Figure 1 represents the time domain, and the vertical axis represents the frequency domain. The basic unit of resources in the time and frequency domains is a resource element (RE, 101), which can be defined as 1 OFDM symbol (102) on the time axis and 1 subcarrier (103) on the frequency axis. In the frequency domain (For example, 12) consecutive REs can constitute one resource block (RB, 104). One subframe (110) on the time axis can include multiple OFDM symbols (102). For example, the length of one subframe can be 1 ms.

[0060] 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.

[0061] 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, 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, cases where the subcarrier spacing setting value μ = 0 (204) and μ = 1 (205) are illustrated. When μ = 0 (204), 1 subframe (201) may be composed of one slot (202), and when μ = 1 (205), 1 subframe (201) may be composed of two slots (203). That is, the number of slots per 1 subframe ( ) may vary, and accordingly the number of slots per frame ( ) may vary. Depending on the subcarrier spacing setting μ and can be defined as [Table 1] below.

[0062] [Table 1]

[0063]

[0064] [Bandwidth Part (BWP)]

[0065] Next, the bandwidth part (BWP) setting in the 5G communication system will be explained in detail with reference to the drawing.

[0066] 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.

[0067] 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.

[0068] [Table 2]

[0069]

[0070] Of course, the above example is not limited, and in addition to the above configuration information, various parameters related to the bandwidth portion can be configured for the terminal. The above information can be transmitted from the base station to the terminal via upper layer signaling, for example, RRC (Radio Resource Control) signaling. At least one bandwidth portion among the configured one or more bandwidth portions can be activated. Whether or not the configured bandwidth portion is activated can be semi-statically transmitted from the base station to the terminal via RRC signaling or dynamically transmitted via DCI.

[0071] According to some embodiments, a terminal before RRC connection can be configured with an initial bandwidth portion (Initial BWP) for initial access from a base station through a Master Information Block (MIB). More specifically, the terminal can receive configuration information about a control resource set (CORESET) and a search space in which a PDCCH for receiving system information required for initial access (which may correspond to Remaining System Information (RMSI) or System Information Block 1 (SIB1)) and search space can be transmitted through the MIB during the initial access phase. The control space and search space configured by the MIB can 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 space #0 through the MIB. Additionally, the base station can notify the terminal of the monitoring cycle and monitoring occasion settings for control area #0, i.e., search space #0, via the MIB. The terminal can consider the frequency range set as control area #0 obtained from the MIB as the initial bandwidth portion for initial access. At this time, the identifier (ID) of the initial bandwidth portion can be considered as 0.

[0072] The settings for the bandwidth supported by the above 5G can be used for various purposes.

[0073] 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.

[0074] 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 (FDM), 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.

[0075] 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.

[0076] In the method for setting the bandwidth portion, terminals prior to RRC connection (Connected) can receive configuration information for the initial bandwidth portion (Initial BWP) through the MIB during the initial access phase. More specifically, the terminal can receive a control region (i.e., CORESET) for a downlink control channel on which a DCI scheduling a System Information Block (SIB) can be transmitted from the MIB of the Physical Broadcast Channel (PBCH). The bandwidth of the control region set by the MIB can be regarded as the initial bandwidth portion, and the terminal can receive the Physical Downlink Shared Channel (PDSCH) on which the SIB is transmitted through the set initial bandwidth portion. In addition to receiving the SIB, the initial bandwidth portion can also be utilized for other system information (Other System Information (OSI), paging, and random access).

[0077] [Bandwidth Part (BWP) Change]

[0078] When one or more bandwidth part values ​​are set for a terminal, the base station can instruct the terminal to change (or switch, transition) the bandwidth part value 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.

[0079] 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:

[0080] [Table 3]

[0081]

[0082] 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.

[0083] 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.

[0084] 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).

[0085] [CA / DC related]

[0086] FIG. 4 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.

[0087] Referring to FIG. 4, 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), and NR MAC (Medium Access Control S40, S55) in the terminal and NR base station, respectively.

[0088] Key features of NR SDAP (S25, S70) may include some of the following:

[0089] - Transfer of user plane data

[0090] - Mapping function between QoS flow and data bearer for both DL and UL

[0091] - Marking function of QoS flow ID for both uplink and downlink (marking QoS flow ID in both DL and UL packets)

[0092] - Ability to map reflective QoS flow to data bearer for uplink SDAP PDUs (reflective QoS flow to DRB mapping for the UL SDAP PDUs).

[0093] For the above SDAP layer device, the terminal can be configured by an 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 instruct 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 to update or reset the mapping information for the QoS flow and data bearer of the uplink and downlink. 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.

[0094] The main functions of NR PDCP (S30, S65) may include some of the following functions:

[0095] - Header compression and decompression (ROHC only)

[0096] - User data transfer function

[0097] - In-sequence delivery of upper layer PDUs

[0098] - Out-of-sequence delivery of upper layer PDUs

[0099] - PDCP PDU reordering for reception

[0100] - Duplicate detection of lower layer SDUs

[0101] - Retransmission function (Retransmission of PDCP SDUs)

[0102] - Encryption and decryption functions (Ciphering and deciphering)

[0103] - Timer-based SDU discard in uplink.

[0104] 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.

[0105] The main functions of NR RLC (S35, S60) may include some of the following functions:

[0106] - Data transfer function (Transfer of upper layer PDUs)

[0107] - In-sequence delivery of upper layer PDUs

[0108] - Out-of-sequence delivery of upper layer PDUs

[0109] - ARQ function (Error Correction through ARQ)

[0110] - Concatenation, segmentation and reassembly of RLC SDUs

[0111] - Re-segmentation of RLC data PDUs

[0112] - Reordering of RLC data PDUs

[0113] - Duplicate detection function

[0114] - Protocol error detection

[0115] - RLC SDU discard function

[0116] - RLC re-establishment function

[0117] 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.

[0118] 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 one RLC SDU is received divided into multiple RLC SDUs, and may include a function of storing and arranging the RLC SN or PDCP SN of received RLC PDUs to record lost RLC PDUs.

[0119] 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 some of the following functions.

[0120] - Mapping function (Mapping between logical channels and transport channels)

[0121] - Multiplexing / demultiplexing of MAC SDUs

[0122] - Scheduling information reporting function

[0123] - HARQ function (Error correction through HARQ)

[0124] - Priority handling between logical channels of one UE

[0125] - Priority handling between UEs by means of dynamic scheduling

[0126] - MBMS service identification function

[0127] - Transport format selection function

[0128] - Padding function

[0129] 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.

[0130] 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 that has 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) using multiple carriers in a single TRP, the base station and the terminal use a protocol structure that has a single structure up to RLC, but multiplexes the PHY layer through the MAC layer, such as S10. As another example, when a base station transmits data to a terminal based on DC (dual connectivity) using multiple carriers in multiple TRPs, the base station and the terminal use a protocol structure that has a single structure up to RLC, but multiplexes the PHY layer through the MAC layer, such as S20.

[0131] [PDCCH: DCI related]

[0132] Next, we will specifically explain downlink control information (DCI) in 5G systems.

[0133] 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.

[0134] 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.

[0135] 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).

[0136] 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.

[0137] [Table 4]

[0138]

[0139] 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.

[0140] [Table 5]

[0141]

[0142] 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.

[0143] [Table 6]

[0144]

[0145] 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.

[0146] [Table 7]

[0147]

[0148] [PDCCH: CORESET, REG, CCE, Search Space]

[0149] Below, the downlink control channel in a 5G communication system will be described in more detail with reference to drawings.

[0150] FIG. 5 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. 5 illustrates an example in which two control regions (Control Region #1 (501), Control Region #2 (502)) are set within a UE bandwidth part (510) in the frequency axis and one slot (520) in the time axis. The control regions (501, 502) may be set to specific frequency resources (503) within the entire UE bandwidth part (510) in the frequency axis. The time axis may be set to one or more OFDM symbols, which may be defined as the control region length (Control Resource Set Duration, 504). Referring to the example illustrated in FIG. 5, Control Region #1 (501) is set to a control region length of two symbols, and Control Region #2 (502) is set to a control region length of one symbol.

[0151] 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 information may include the following:

[0152] [Table 8]

[0153]

[0154] 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.

[0155] FIG. 6 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. 6, the basic unit of time and frequency resources that constitute a control channel can be referred to as a REG (Resource Element Group, 603), and a REG (603) can be defined as 1 OFDM symbol (601) on the time axis and 1 PRB (Physical Resource Block, 602) on the frequency axis, i.e., 12 subcarriers. A base station can concatenate REGs (603) to constitute a downlink control channel allocation unit.

[0156] As illustrated in FIG. 6, if the basic unit to which a downlink control channel is allocated in 5G is called a CCE (Control Channel Element, 604), 1 CCE (604) can be composed of multiple REGs (603). Taking the REG (603) illustrated in FIG. 6 as an example, the REG (603) can be composed of 12 REs, and if 1 CCE (604) is composed of 6 REGs (603), 1 CCE (604) can be composed of 72 REs. When a downlink control region is established, the region can be composed of multiple CCEs (604), and a specific downlink control channel can be mapped to one or multiple CCEs (604) and transmitted according to the aggregation level (AL) within the control region. CCEs (604) within the control area are distinguished by numbers, and the numbers of the CCEs (604) can be assigned according to a logical mapping method.

[0157] The basic unit of the downlink control channel illustrated in FIG. 6, that is, the REG (603), may include both the REs to which the DCI is mapped and the areas to which the DMRS (605), which is a reference signal for decoding the REs, is mapped. As shown in FIG. 6, three DMRSs (605) may be transmitted within one REG (603). 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.

[0158] 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.

[0159] In 5G, parameters for the search space for PDCCH can be configured from the base station to the terminal through 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 included.

[0160] [Table 9]

[0161]

[0162] 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.

[0163] 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.

[0164] 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.

[0165] - 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

[0166] - DCI format 2_0 with CRC scrambled by SFI-RNTI

[0167] - DCI format 2_1 with CRC scrambled by INT-RNTI

[0168] - DCI format 2_2 with CRC scrambled by TPC-PUSCH-RNTI, TPC-PUCCH-RNTI

[0169] - DCI format 2_3 with CRC scrambled by TPC-SRS-RNTI

[0170] 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.

[0171] - DCI format 0_0 / 1_0 with CRC scrambled by C-RNTI, CS-RNTI, TC-RNTI

[0172] - DCI format 1_0 / 1_1 with CRC scrambled by C-RNTI, CS-RNTI, TC-RNTI

[0173] The RNTIs specified may follow the definitions and uses below.

[0174] C-RNTI (Cell RNTI): For terminal-specific PDSCH scheduling purposes

[0175] TC-RNTI (Temporary Cell RNTI): For terminal-specific PDSCH scheduling purposes

[0176] CS-RNTI (Configured Scheduling RNTI): Used for terminal-specific PDSCH scheduling that is set semi-statically.

[0177] RA-RNTI (Random Access RNTI): Used for PDSCH scheduling in the random access phase.

[0178] P-RNTI (Paging RNTI): Used for scheduling PDSCH where paging is transmitted.

[0179] SI-RNTI (System Information RNTI): Used for scheduling PDSCH where system information is transmitted.

[0180] INT-RNTI (Interruption RNTI): Used to indicate whether pucturing is in progress for PDSCH.

[0181] TPC-PUSCH-RNTI (Transmit Power Control for PUSCH RNTI): Used to indicate power control commands for PUSCH.

[0182] TPC-PUCCH-RNTI (Transmit Power Control for PUCCH RNTI): Used to indicate power control commands for PUCCH.

[0183] TPC-SRS-RNTI (Transmit Power Control for SRS RNTI): Used to indicate power control commands for SRS.

[0184] The aforementioned specified DCI formats may follow the definitions below.

[0185] [Table 10]

[0186]

[0187] In 5G, the search space of aggregation level L in the control region p and search space set s can be expressed as in [Mathematical Formula 1] below.

[0188] [Mathematical Formula 1]

[0189]

[0190] - : Integration level

[0191] - : Carrier Index

[0192] - : Total number of CCEs existing within the control region p

[0193] - : slot index

[0194] - : Number of PDCCH candidates for aggregation level L

[0195] - = 0, ..., : PDCCH candidate index of aggregation level L

[0196] - = 0, ...,

[0197] - , , , , ,

[0198] - : Terminal identifier

[0199] The value can be 0 for a common search space.

[0200] 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.

[0201] In 5G, since multiple search space sets can be configured with different parameters (e.g., parameters in Table 9), 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.

[0202] [Regarding terminal capability reporting]

[0203] 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.

[0204] 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.

[0205] 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.

[0206] 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.

[0207] 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.

[0208] 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."

[0209] 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.

[0210] 5. Also, if the requested rat Type is eutra-nr and has influence, 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.

[0211] 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.

[0212] [Multi-DCI based Multi-TRP]

[0213] As one embodiment of the present disclosure, a multi-DCI-based multi-TRP transmission method is described. The multi-DCI-based multi-TRP transmission method can establish a downlink control channel for NC-JT transmission based on a multi-PDCCH.

[0214] 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.

[0215] * 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.

[0216] ** In the present disclosure, if the number of types of CORESETPoolIndex of each of the multiple CORESETs included in the upper layer signaling PDCCH-Config exceeds 1, i.e., if each CORESET has a different CORESETPoolIndex, the terminal may consider that the base station can use the multi-DCI based multi-TRP transmission method.

[0217] ** Differently, in the present disclosure, if each of the multiple CORESETs included in the upper layer signaling PDCCH-Config has only one type of CORESETPoolIndex, that is, if all CORESETs have the same CORESETPoolIndex of 0 or 1, the terminal can assume that the base station transmits using a single-TRP rather than using a multi-DCI based multi-TRP transmission method.

[0218] * 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.

[0219] * 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.

[0220] * 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.

[0221] 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.

[0222] The above settings can be independent on a per-cell or per-BWP basis. 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 on the PCell, while NC-JT transmission is not configured on the SCell without the CORESETPoolIndex value set.

[0223] The PDSCH TCI state activation / deactivation MAC-CE applicable to the multi-DCI based multi-TRP transmission method can follow the above-mentioned FIGS. 7a and 7b. If the UE does not have CORESETPoolIndex set for each of all CORESETs in the upper layer signaling PDCCH-Config, the UE can ignore the CORESET Pool ID field (755) in the corresponding MAC-CE (750). If the UE can support the multi-DCI based multi-TRP transmission method, i.e., if each CORESET in the upper layer signaling PDCCH-Config of the UE has a different CORESETPoolIndex, the UE can activate the TCI state in the DCI included in the PDCCH transmitted in the CORESETs having the same CORESETPoolIndex value as the CORESET Pool ID field (755) value in the corresponding MAC-CE (750). For example, if the value of the CORESET Pool ID field (755) within the MAC-CE (750) is 0, the TCI state within the DCI included in the PDCCH transmitted from CORESETs with CORESETPoolIndex of 0 may follow the activation information of the MAC-CE.

[0224] When a terminal is configured to use a multi-DCI based multi-TRP transmission method from a base station, that is, when each of multiple CORESETs included in the upper layer signaling PDCCH-Config has more than one type of CORESETPoolIndex or when each CORESET has a different CORESETPoolIndex, the terminal can know that the following restrictions exist for PDSCHs scheduled from PDCCHs within each CORESET having two different CORESETPoolIndexes.

[0225] 1) If the PDSCHs indicated by the PDCCHs within each CORESET having two different CORESETPoolIndexes completely or partially overlap, the TCI states indicated by each PDCCH can be applied to different CDM groups. That is, two or more TCI states may not be applied to a single CDM group.

[0226] 2) The terminal can expect that the actual number of front-loaded DMRS symbols, the actual number of additional DMRS symbols, the location of actual DMRS symbols, and the DMRS type of each PDSCH will not be different when the PDSCHs indicated from the PDCCHs within each CORESET having two different CORESETPoolIndexes overlap completely or partially.

[0227] 3) The terminal can expect that the bandwidth portion indicated by the PDCCH within each CORESET having two different CORESETPoolIndexes will be the same and that the subcarrier spacing will also be the same.

[0228] 4) The terminal can expect that each PDCCH will fully contain information about the PDSCH scheduled from the PDCCH within each CORESET having two different CORESETPoolIndexes.

[0229] [NC-JT related]

[0230] 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.

[0231] 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.

[0232] 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.

[0233] The above-described NC-JT transmission can be applied to at least one channel among the downlink data channel (PDSCH), downlink control channel (PDCCH), uplink data channel (PUSCH), and uplink control channel (PUCCH). When transmitting 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, and this may adversely affect the reception performance of the PDCCH transmitting the DCI. Therefore, in order to support JT of PDSCH, it is necessary to carefully design a tradeoff between the amount of DCI information and the reception performance of control information.

[0234] FIG. 8 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.

[0235] Referring to FIG. 8, examples for PDSCH transmission are explained for each technique of joint transmission (JT), and examples for allocating radio resources for each TRP are shown.

[0236] Referring to FIG. 8, an example (800) for coherent joint transmission (C-JT) supporting coherent precoding between each cell, TRP or / and beam is illustrated.

[0237] In the case of C-JT, TRP A (805) and TRP B (810) transmit a single data (PDSCH) to the terminal (815), and joint precoding can be performed on multiple TRPs. This may mean that DMRS is transmitted through the same DMRS ports for TRP A (805) and TRP B (810) to transmit the same PDSCH. For example, TRP A (805) and TRP B (810) 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.

[0238] FIG. 8 illustrates an example (820) of Non-Coherent Joint Transmission (NC-JT) supporting non-coherent precoding between each cell, TRP, or / and beam for PDSCH transmission.

[0239] In the case of NC-JT, each cell, TRP, or / and beam transmits a PDSCH to the terminal (835), 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.

[0240] At this time, various wireless resource allocations can be considered, such as when the frequency and time resources used by multiple TRPs for PDSCH transmission are all the same (840), when the frequency and time resources used by multiple TRPs do not overlap at all (845), and when some of the frequency and time resources used by multiple TRPs overlap (850).

[0241] To support NC-JT, DCIs of various forms, structures, and relationships can be considered to simultaneously allocate multiple PDSCHs to a single terminal.

[0242] FIG. 9 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.

[0243] Referring to FIG. 9, case #1 (900) 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 terminal 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.

[0244] Case #2 (905) shows 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)), 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.

[0245] 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.

[0246] 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.

[0247] Case #3 (910) shows an example in which, in a situation 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.

[0248] 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.

[0249] Case #3 (910) 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 (900) or case #2 (905).

[0250] Case #4 (915) is an example of transmitting control information for PDSCHs transmitted from (N-1) additional TRPs (TRP#1 to TRP#(N-1)) in the same DCI (Long DCI) as the control information for PDSCHs transmitted from the serving TRP in a situation where (N-1) different PDSCHs are transmitted from (N-1) additional TRPs in addition to the serving TRP (TRP#0) used for single PDSCH transmission. 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 (915), the complexity of DCI blind decoding of the UE may not increase, but the degree of freedom in PDSCH control or allocation may be low, such as because the number of cooperative TRPs is limited due to the long DCI payload limitation.

[0251] 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.

[0252] In the following description and examples, the aforementioned cases #1 (900), #2 (905), and #3 (910), 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 (915), 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 Transmission Relays (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.

[0253] 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.

[0254] 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.

[0255] In the present invention, the wireless protocol structure for NC-JT 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. 4 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. 4.

[0256] 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.

[0257] [Single-DCI based Multi-TRP]

[0258] As one embodiment of the present disclosure, a single-DCI-based multi-TRP transmission method is described. The single-DCI-based multi-TRP transmission method can establish a downlink control channel for NC-JT transmission based on a single-PDCCH.

[0259] In a single DCI-based multi-TRP transmission method, a PDSCH 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 of 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.

[0260] As another example, if at least one codepoint among all codepoints in the TCI state field within the DCI indicates two TCI states, the UE may assume that the base station can transmit based on the single-DCI based multi-TRP method. In this case, at least one codepoint indicating two TCI states within the TCI state field may be activated via the Enhanced PDSCH TCI state activation / deactivation MAC-CE.

[0261] Figure 10 is a diagram illustrating the structure of the Enhanced PDSCH TCI state activation / deactivation MAC-CE. The meaning of each field within the MAC CE and the values ​​that can be set for each field are as shown in [Table 11] below.

[0262] [Table 11]

[0263]

[0264] In Fig. 10, if the value of the C0 field (1005) is 1, the corresponding MAC-CE is the TCI state ID 0,1 In addition to field (1010), TCI state ID 0,2 It may include field (1015). This is the TCI state ID for the 0th codepoint of the TCI state field included in the DCI. 0,1 and TCI state ID 0,2 This means that the MAC-CE is activated, and if the base station instructs the terminal with the corresponding codepoint, the terminal can be instructed with two TCI states. If the value of the C0 field (1005) is 0, the corresponding MAC-CE is the TCI state ID. 0,2 It cannot contain field (1015), which is the TCI state ID for the 0th codepoint of the TCI state field contained within the DCI. 0,1 This means that one TCI state corresponding to is activated.

[0265] 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.

[0266] [Unified TCI state MAC-CE]

[0267] Hereinafter, a single TCI state indication and activation method based on the integrated TCI scheme is described. The terminal receives a PDSCH including the following MAC-CE from the base station, and from 3 slots after transmitting a HARQ-ACK for the corresponding PDSCH to the base station, the terminal can interpret each code point of the TCI state field in DCI format 1_1 or 1_2 based on the information in the MAC-CE received from the base station. That is, the terminal can activate each entry of the MAC-CE received from the base station to each code point of the TCI state field in DCI format 1_1 or 1_2.

[0268] FIG. 11 is a diagram illustrating another MAC-CE structure for activating and indicating a joint TCI state or separate DL or UL TCI state in a wireless communication system according to an embodiment of the present disclosure. The meaning of each field within the MAC-CE structure may be as follows.

[0269] - Serving Cell ID (11-00): This field can indicate which serving cell the MAC-CE is applied to. The length of this field can be 5 bits. If the serving cell indicated by this field is included in one or more of the upper layer signaling simultaneousU-TCI-UpdateList1, simultaneousU-TCI-UpdateList2, simultaneousU-TCI-UpdateList3, or simultaneousU-TCI-UpdateList4, the MAC-CE can be applied to all serving cells included in one or more of the lists simultaneousU-TCI-UpdateList1, simultaneousU-TCI-UpdateList2, simultaneousU-TCI-UpdateList3, or simultaneousU-TCI-UpdateList4 that include the serving cell indicated by this field.

[0270] - DL BWP ID (11-05): This field can indicate which DL BWP the corresponding MAC-CE applies to, and the meaning of each code point in this field can correspond to each code point of the bandwidth part indicator in the DCI. The length of this field can be 2 bits.

[0271] - UL BWP ID (11-10): This field can indicate which UL BWP the corresponding MAC-CE applies to, and the meaning of each code point in this field can correspond to each code point of the bandwidth part indicator in the DCI. The length of this field can be 2 bits.

[0272] - P i(11-15): This field can indicate whether each code point in the TCI state field in DCI format 1_1 or 1_2 has multiple TCI states or a single TCI state. If P i If the value of is 1, it means that the corresponding i-th code point has multiple TCI states, which may mean that the corresponding code point may contain separate DL TCI states and separate UL TCI states. If P i If the value is 0, it means that the corresponding ith code point has a single TCI state, which may mean that the corresponding code point may contain one of a joint TCI state, a separate DCI TCI state, or a separate UL TCI state.

[0273] - D / U (11-20): This field can indicate whether the TCI state ID field in the same octet is a joint TCI state, a separate DL TCI state, or a separate UL TCI state. If this field is 1, the TCI state ID field in the same octet can be a joint TCI state or a separate DL TCI state, and if this field is 0, the TCI state ID field in the same octet can be a separate UL TCI state.

[0274] - TCI state ID (11-25): This field can indicate a TCI state that can be identified by the upper layer signaling TCI-StateId. If the D / U field is set to 1, this field can be used to express the TCI-StateId, which can be expressed in 7 bits. If the D / U field is set to 0, the MSB (most significant bit) of this field can be considered a reserved bit, and the remaining 6 bits can be used to express the upper layer signaling UL-TCIState-Id. The maximum number of TCI states that can be activated is 8 for a joint TCI state and 16 for separate DL or UL TCI states.

[0275] - R (11-30): Indicates reserved bits and can be set to 0.

[0276] For the MAC-CE structure of FIG. 11 described above, the terminal can include the third octet including the P1, P2, ..., P8 fields in FIG. 11 in the MAC-CE structure, regardless of whether unifiedTCI-StateType-r17 in MIMOparam-r17 in ServingCellConfig, which is an upper layer signaling, is set to joint or separate. In this case, the terminal can perform TCI state activation using the fixed MAC-CE structure regardless of the upper layer signaling set by the base station. As another example, for the MAC-CE structure of FIG. 11 described above, the terminal can omit the third octet including the P1, P2, ..., P8 fields in FIG. 11 when unifiedTCI-StateType-r17 in MIMOparam-r17 in ServingCellConfig, which is an upper layer signaling, is set to joint. In this case, the terminal can save up to 8 bits of the payload of the corresponding MAC-CE according to the upper layer signaling set by the base station. In addition, all D / U fields located from the fourth octet to the first bit in Fig. 11 can be regarded as R fields, and all corresponding R fields can be set to 0 bits.

[0277] [Unified TCI state]

[0278] Hereinafter, a single TCI state indication and activation method based on the unified TCI scheme is described. The unified TCI scheme can refer to a method of integrating and managing the transmission and reception beam management methods, which were distinguished into the TCI state method used for downlink reception of the terminal in the existing Rel-15 and 16 and the spatial relation info method used for uplink transmission, into a TCI state. Therefore, when the terminal is instructed by the base station based on the unified TCI scheme, it can perform beam management using the TCI state even for uplink transmission. If the terminal has set a TCI-State, which is an upper layer signaling with the tci-stateId-r17, which is an upper layer signaling, from the base station, the terminal can perform operations based on the unified TCI scheme using the corresponding TCI-State. The TCI-State can exist in two forms: a joint TCI state or a separate TCI state.

[0279] The first type is a joint TCI state, and the terminal can be instructed by the base station to use both the TCI state to apply to uplink transmission and downlink reception through a single TCI-State. If the terminal is instructed to use a TCI-State based on a joint TCI state, the terminal can use the RS corresponding to qcl-Type1 in the TCI-State based on the joint TCI state to instruct the parameters to use for downlink channel estimation, and the RS corresponding to qcl-Type2 to instruct the parameters to use as a downlink reception beam or reception filter. If the terminal is instructed to use a TCI-State based on a joint TCI state, the terminal can use the RS corresponding to qcl-Type2 in the TCI-State based on the joint DL / UL TCI state to instruct the parameters to use as an uplink transmission beam or transmission filter. In this case, if the terminal is instructed to use a joint TCI state, the terminal can apply the same beam to both uplink transmission and downlink reception.

[0280] The second form is a separate TCI state, in which the terminal can be individually instructed by the base station to select a UL TCI state to apply to uplink transmission and a DL TCI state to apply to downlink reception. If the terminal is instructed to select a UL TCI state, the terminal can be instructed to select parameters to use as an uplink transmission beam or transmission filter using the reference RS or source RS configured in the UL TCI state. If the terminal is instructed to select a DL TCI state, the terminal can be instructed to select parameters to use for downlink channel estimation using the RS corresponding to qcl-Type1 configured in the DL TCI state, and to select parameters to use as a downlink reception beam or reception filter using the RS corresponding to qcl-Type2.

[0281] If the terminal is instructed with both the DL TCI state and the UL TCI state, the terminal can be instructed with parameters to be used as an uplink transmission beam or a transmission filter using the reference RS or source RS set in the corresponding UL TCI state, and can be instructed with parameters to be used for downlink channel estimation using the RS corresponding to qcl-Type1 set in the corresponding DL TCI state, and can be instructed with parameters to be used as a downlink reception beam or a reception filter using the RS corresponding to qcl-Type2. In this case, if the reference RS or source RS set in the DL TCI state and UL TCI state to which the terminal is instructed are different, the terminal can individually apply beams to uplink transmission and downlink reception, respectively, based on the instructed UL TCI state and DL TCI state.

[0282] A terminal can receive a joint TCI state from a base station for each bandwidth part within a specific cell through upper layer signaling up to 128 times, and among the separate TCI states, a DL TCI state can be set for each bandwidth part within a specific cell up to 64 or 128 times through upper layer signaling based on a terminal capability report. Among the separate TCI states, the DL TCI state and the joint TCI state can use the same upper layer signaling structure. For example, if 128 joint TCI states are set and 64 DL TCI states are set among the separate TCI states, the 64 DL TCI states can be included in the 128 joint TCI states.

[0283] Among the separate TCI states, the UL TCI state can be set to a maximum of 32 or 64 upper layer signaling for each specific bandwidth part within a specific cell based on the terminal capability report, and like the relationship between the DL TCI state and the joint TCI state among the separate TCI states, the UL TCI state and the joint TCI state among the separate TCI can also use the same upper layer signaling structure, and the UL TCI state among the separate TCI can use different upper layer signaling structures from the joint TCI state and the DL TCI state among the separate TCI states.

[0284] The use of different or identical upper layer signaling structures may be defined in the specification, or may be distinguished through another upper layer signaling established by the base station based on a terminal capability report containing information on which of the two usage modes the terminal can support.

[0285] The terminal can receive transmission and reception beam-related instructions in an integrated TCI manner using one of the joint TCI state and separate TCI state configured by the base station. The terminal can be configured by the base station via upper layer signaling whether to use either the joint TCI state or separate TCI state.

[0286] The terminal receives transmission / reception beam-related instructions using one of the methods selected from the joint TCI state and the separate TCI state through upper layer signaling. At this time, there may be two transmission / reception beam instruction methods from the base station: a MAC-CE-based instruction method and a MAC-CE-based activation and DCI-based instruction method.

[0287] If a terminal receives a transmission / reception beam-related instruction using a joint TCI state method through upper layer signaling, the terminal can perform a transmission / reception beam application operation by receiving a MAC-CE indicating the joint TCI state from a base station, and the base station can schedule reception of a PDSCH including the MAC-CE through a PDCCH for the terminal. If the MAC-CE includes one joint TCI state, the UE can use the indicated joint TCI state to determine the uplink transmission beam or transmission filter and the downlink reception beam or reception filter starting 3 ms after transmitting a PUCCH including HARQ-ACK information indicating whether reception of the PDSCH including the MAC-CE is successful. If the MAC-CE includes two or more joint TCI states, the UE can confirm that the multiple joint TCI states indicated by the MAC-CE correspond to each code point of the TCI state field of DCI format 1_1 or 1_2 starting 3 ms after transmitting a PUCCH including HARQ-ACK information indicating whether reception of the PDSCH including the MAC-CE is successful. Then, the UE can receive DCI format 1_1 or 1_2 and apply one joint TCI state indicated by the TCI state field in the corresponding DCI to the uplink transmission and downlink reception beams. At this time, DCI format 1_1 or 1_2 may or may not include downlink data channel scheduling information (with DL assignment) or may not include it (without DL assignment).

[0288] If a terminal receives an instruction related to a transmit / receive beam using a separate TCI state method through upper layer signaling, the terminal can perform a transmit / receive beam application operation by receiving a MAC-CE indicating a separate TCI state from a base station, and the base station can schedule reception of a PDSCH including the corresponding MAC-CE to the terminal through a PDCCH. If the MAC-CE includes only one set of separate TCI states, the terminal can determine an uplink transmit beam or transmit filter and a downlink receive beam or receive filter using the separate TCI states included in the indicated separate TCI state set starting from 3 ms after transmitting a PUCCH including HARQ-ACK information indicating whether reception of the corresponding PDSCH was successful. At this time, the separate TCI state set may mean single or multiple separate TCI states that one code point of the TCI state field in DCI format 1_1 or 1_2 can have, and one separate TCI state set may include one DL TCI state, one UL TCI state, or one DL TCI state and one UL TCI state. If there are two or more separate TCI state sets included in the MAC-CE, the UE may confirm that the multiple separate TCI state sets indicated by the MAC-CE correspond to each code point of the TCI state field of DCI format 1_1 or 1_2 starting from 3 ms after transmitting the PUCCH including HARQ-ACK information indicating whether reception for the corresponding PDSCH was successful, and may activate the indicated separate TCI state set.At this time, each code point of the TCI state field of DCI format 1_1 or 1_2 can indicate one DL TCI state, one UL TCI state, or one DL TCI state and one UL TCI state each. The terminal can receive DCI format 1_1 or 1_2 and apply a separate set of TCI states indicated by the TCI state field in the corresponding DCI to the uplink transmission and downlink reception beams. At this time, DCI format 1_1 or 1_2 may include downlink data channel scheduling information (with DL assignment) or may not include it (without DL assignment).

[0289] FIG. 12 is a diagram illustrating beam application times that may be considered when using an integrated TCI scheme in a wireless communication system according to an embodiment of the present disclosure. As described above, a terminal may receive DCI format 1_1 or 1_2 from a base station, including (with DL assignment) or not including (without DL assignment) downlink data channel scheduling information, and apply one joint TCI state or a set of separate TCI states indicated by the TCI state field in the corresponding DCI to uplink transmission and downlink reception beams.

[0290] - DCI format 1_1 or 1_2 with DL assignment (12-00): If the terminal receives DCI format 1_1 or 1_2 including downlink data channel scheduling information from the base station (12-01) and indicates one joint TCI state or a separate TCI state set based on the integrated TCI method, the terminal receives a PDSCH scheduled based on the received DCI (12-05), and can transmit a PUCCH including an HARQ-ACK indicating whether reception of the DCI and the PDSCH was successful (12-10). At this time, the HARQ-ACK can include the meaning of whether reception of both the DCI and the PDSCH was successful, and if at least one of the DCI and the PDSCH was not received, the terminal can transmit a NACK, and if reception of both was successful, the terminal can transmit an ACK.

[0291] - DCI format 1_1 or 1_2 without DL assignment (12-50): If the terminal receives DCI format 1_1 or 1_2 from the base station that does not include downlink data channel scheduling information (12-55) and indicates one joint TCI state or a set of separate TCI states based on the integrated TCI method, the terminal may assume at least one combination of the following for the corresponding DCI:

[0292] ■ Includes scrambled CRC using CS-RNTI.

[0293] ■ The value of all bits assigned to all fields used as RV (Redundancy Version) fields is 1.

[0294] ■ The value of all bits assigned to all fields used as MCS (Modulation and Coding Scheme) fields is 1.

[0295] ■ The value of all bits assigned to all fields used as NDI (New Data Indication) fields is 0.

[0296] ■ For FDRA (Frequency Domain Resource Allocation) Type 0, the value of all bits allocated to the FDRA field is 0, for FDRA Type 1, the value of all bits allocated to the FDRA field is 1, and when the FDRA method is dynamicSwitch, the value of all bits allocated to the FDRA field is 0.

[0297] The terminal can transmit a PUCCH including a HARQ-ACK indicating whether reception was successful for the DCI format 1_1 or 1_2 assuming the above-described matters (12-60).

[0298] - For both DCI format 1_1 or 1_2 with DL assignment (12-00) and without DL assignment (12-50), if a new TCI state indicated through DCI (12-01, 12-55) is the same as a TCI state that has already been indicated and applied to an uplink transmission and downlink reception beam, the terminal may maintain the previously applied TCI state, and if the new TCI state is different from the previously indicated TCI state, the terminal may determine the application time of a set of joint TCI states or separate TCI states that can be indicated from the TCI state field included in the DCI as the time after the first slot (12-20, 12-70) after the time equivalent to BAT (beam application time, 12-15, 12-65) after the PUCCH transmission, and (12-30, 12-80) before the corresponding slot (12-20, 12-70). Until 12-75, the previously indicated TCI-state can be used.

[0299] - For both DCI format 1_1 or 1_2 with DL assignment (12-00) and without DL assignment (12-50), the BAT can be set by upper layer signaling based on the terminal capability report information as a specific number of OFDM symbols, and the numerology for the BAT and the first slot after the BAT can be determined based on the smallest numerology among all cells to which the joint TCI state or separate TCI state set indicated through the DCI applies.

[0300] A terminal can apply one joint TCI state indicated via MAC-CE or DCI to reception of control resource sets connected to all terminal-specific search spaces, reception of PDSCHs scheduled as PDCCHs transmitted from the control resource sets, transmission of PUSCHs, and transmission of all PUCCH resources.

[0301] A terminal may apply one separate TCI state set, if one separate TCI state set indicated via MAC-CE or DCI includes one DL TCI state, to reception for control resource sets connected to all terminal-specific search spaces, to reception for PDSCH scheduled as PDCCH transmitted from the control resource set, and to all PUSCH and PUCCH resources based on the previously indicated UL TCI state.

[0302] A terminal can apply a separate TCI state set indicated via MAC-CE or DCI to all PUSCH and PUCCH resources if it includes one UL TCI state, and can apply it to reception of control resource sets connected to all terminal-specific search spaces based on previously indicated DL TCI states, and to reception of PDSCH scheduled as PDCCH transmitted from the corresponding control resource set.

[0303] When a separate set of TCI states indicated via MAC-CE or DCI includes one DL TCI state and one UL TCI state, the terminal may apply the DL TCI state to reception for all control resource sets associated with the terminal-specific search space and to reception for PDSCH scheduled as PDCCH transmitted from the control resource set, and may apply the UL TCI state to all PUSCH and PUCCH resources.

[0304] [Rel-15 PCell BFR]

[0305] Next, we will describe in detail the beam failure recovery operation within the primary cell (PCell). In order to enable smooth downlink transmission between the base station and the terminal, the terminal must be able to normally receive the PDCCH transmitted by the base station. If the terminal cannot normally receive the PDCCH, it can be said that a beam failure has occurred between the base station and the terminal. The criteria and method for determining whether the terminal can normally receive the PDCCH will be described later. In the NR system, the beam failure recovery (BFR) procedure is supported to enable smooth downlink transmission by coping with dynamic beam failure between the base station and the terminal.

[0306] The BFR procedure in the NR system can be broadly divided into four steps as follows.

[0307] - Beam failure detection process

[0308] - New candidate beam identification process

[0309] - Beam failure recovery request process

[0310] - gNB response reception process

[0311] The first step is to detect beam failure, which will be described later as the beam failure detection (BFD) process. The BFD process determines whether the terminal can normally receive the PDCCH. If it determines that the terminal cannot normally receive the PDCCH, it reports the beam failure to the upper layer. The upper layer of the terminal can detect the beam failure based on this report and decide whether to proceed with the next BFR step.

[0312] The criterion for determining whether a terminal can normally receive a PDCCH is the terminal's hypothetical PDCCH reception block error rate (BLER), which can be determined by comparing it with a predetermined threshold. To calculate the terminal's hypothetical PDCCH reception BLER, a set of reference signals (RSs) for BFD is required, which will be described below as the BFD RS set.

[0313] A BFD RS set can include at most two RSs, which can be periodic CSI-RSs transmitted through a single port or synchronous / broadcast channel blocks (SS / PBCH blocks, SSB). A BFD RS set can be configured through higher layer signaling of a base station. If a BFD RS set is not configured through higher layer signaling, some or all of the RSs referenced in the activated TCI state of the CORESET(s) configured for PDCCH monitoring of the UE can be included in the BFD RS set. If there are two or more RSs referenced in the TCI state, an RS referenced for 'QCL-typeD' including beam information can be included in the BFD RS set. The UE can calculate a virtual PDCCH reception BLER based only on the RSs referenced in the activated TCI state of the CORESET(s) configured for PDCCH monitoring among the RSs included in the BFD RS set. The terminal can calculate a virtual PDCCH reception BLER by referring to [Table 12] below.

[0314] [Table 12]

[0315]

[0316] [Table 12] provides settings for a virtual PDCCH that a terminal references when calculating a virtual PDCCH reception BLER. Referring to [Table 12], a terminal can calculate a reception BLER of a virtual PDCCH assuming the number of OFDM symbols, bandwidth, subcarrier spacing, and CP (cyclic prefix) length of CORESET(s) with an activated TCI state referencing an RS included in a BFD RS set.

[0317] The UE calculates a virtual PDCCH reception BLER for all CORESETs with activated TCI states referencing RSs included in the BFD RS set, and reports a beam failure indication to the upper layer if the virtual PDCCH reception BLER values ​​for all BFD-RSs exceed a configured threshold. When the upper layer of the UE receives a beam failure indication report, it increments the beam failure instance count, and when the count reaches a configured maximum value, it can decide whether to perform the next process of BFR and can refer to the following parameters configured for the upper layer operation process.

[0318] * beamFailureInstanceMaxCount: The maximum number of beam failure indication reports from the terminal sublayer required to perform the next step of BFR.

[0319] * beamFailureDetectionTimer: Sets a timer to reset the number of beam failure reports from the terminal.

[0320] The second step in the BFR procedure in NR systems is to find a new beam with good channel conditions, which will be described later as the new candidate beam identification process. When the upper layer of the terminal detects beam failure and decides to proceed with the process of finding a new beam, the upper layer of the terminal can request the physical layer of the terminal to report information about the new candidate beam, such as L1-RSRP (reference signal received power). To enable the terminal to calculate information about the new candidate beam, the base station can configure a candidate beam RS set to the terminal through upper layer signaling. The candidate beam RS set can include up to 16 RSs, and the RSs can be periodic CSI-RS or SSB. When the upper layer of the terminal requests the terminal to report information about a new candidate beam, the terminal reports the index information and the L1-RSRP measurement value of the RS among the RSs included in the candidate beam RS set, which has an L1-RSRP value greater than the RSRP threshold set through upper layer signaling. If the RS is a CSI-RS, the terminal can consider the value obtained by applying the upper layer signaling powerControlOffsetSS to the received power of the CSI-RS as the final L1-RSRP measurement value and compare it with the RSRP threshold. The upper layer of the terminal can obtain information about a new beam with good channel conditions through the report about the candidate beam RS from the physical layer of the terminal.

[0321] If not in DRX mode, if the status of the radio link for all BFD RSs is lower than the RSRP threshold, the physical layer of the terminal may indicate BFD information to the upper layer of the terminal, and the period of BFD information indication may be determined as the shorter time between the shortest transmission period of SSB or periodic CSI-RS transmitted from PCell or PSCell and 2 ms. If in DRX mode, the physical layer of the terminal may indicate BFD information to the upper layer of the terminal according to the period defined in the TS38.133 standard.

[0322] If the upper layer of the terminal obtains information about a new beam with a good channel condition exceeding the RSRP threshold from the physical layer of the terminal, the upper layer of the terminal selects one of the new beams with a good channel condition exceeding the RSRP threshold and notifies the physical layer, and the terminal transmits a request signal for BFR to the base station. This corresponds to the third step of the BFR procedure and will be described below as the BFR request process. Based on the information about the new beam, the upper layer of the terminal selects a new RS to be referenced by the terminal for the BFR request from the candidate beam RS set and notifies the physical layer of the new RS. The terminal can obtain configuration information for the PRACH (physical random access channel) transmission to send the BFR request through the new RS information for the BFR request and the BFR request resource information configured through the upper layer signaling. For example, the base station and the terminal can exchange upper layer signaling information as shown in [Table 13] below to convey configuration information for the PRACH transmission to send the BFR request.

[0323] [Table 13]

[0324]

[0325] The upper layer signaling information, BeamFailureRecoveryConfig, contains information about the PRACH transmission that will send the BFR request. The information contained in BeamFailureRecoveryConfig can have the following meanings. That is, BeamFailureRecoveryConfig can contain the following information.

[0326] - rootSequenceIndex-BFR: Root sequence index of the sequence used for PRACH transmission

[0327] - rach-ConfigBFR: Includes parameters for PRACH transmission, including PRACH configuration index, number of frequency resources, frequency resource starting point, response monitoring window, and parameters for adjusting PRACH transmission strength.

[0328] - rsrp-ThresholdSSB: RSRP threshold for selecting a new beam among RSs included in the candidate beam RS set

[0329] - candidateBeamRSList: candidate beam RS set

[0330] - ssb-perRACH-Occasion: The number of SSBs associated with a RACH (Random Access Channel) transmission occasion.

[0331] - ra-ssb-OccasionMaskIndex: PRACH mask index for terminal random access resource selection

[0332] - recoverySearchSpaceId: Search space index for receiving PDCCH used to transmit the base station's Random Access Response (RAR) signal in response to a BFR request.

[0333] - ra-Prioritization: A set of parameters used in random access processes with priorities.

[0334] - beamFailureRecoveryTimer: Timer to initialize settings for PRACH resources to send BFR requests.

[0335] - msg1-SubcarrierSpacing-v1530: Subcarrier spacing of PRACH transmissions to send BFR requests.

[0336] The terminal can transmit a BFR request signal to the base station by referencing the configuration information for the PRACH transmission that will send the BFR request. As shown in [Table 13], the terminal can configure the PRACH resources associated with each candidate beam RS through the upper layer signaling, PRACH-ResourceDedicatedBFR.

[0337] The fourth step in the BFR procedure in the NR system is the process in which the base station, having received the terminal's BFR request signal, sends a response signal to the terminal. This process will be described below as the gNB response process. This process can be explained using Fig. 13.

[0338] FIG. 13 is a diagram illustrating a process of a base station responding to a BFR request signal of a terminal in a PCell BFR operation according to an embodiment of the present disclosure. In order to respond to the BFRQ signal of the terminal, the base station can transmit a PDCCH using resources of a search space set by upper layer signaling to the terminal. Among the configuration parameters based on upper layer signaling for the BFRQ set for the terminal and the response process of the base station, the signaling information, BeamFailureRecoveryConfig, includes recoverySearchSpaceId, which is a search space index for receiving a PDCCH used for transmitting a random access response signal of the base station according to the BFR request. If the PRACH transmission (13-00) connected to the candidate beam RS selected by the terminal is performed in the n-th slot (13-05), the terminal can monitor a PDCCH including a CRC scrambled with C-RNTI or MCS-C-RNTI from the n+4th slot (13-10) in the search space having the recoverySearchSpaceId. When the terminal monitors a PDCCH in the search space having the above recoverySearchSpaceId and receives a PDSCH scheduled through the PDCCH, the terminal can assume that the DMRS of the PDCCH and the PDSCH have the same quasi-co-location (QCL) parameters as the candidate beam RS corresponding to the PRACH transmitted by the terminal (13-15). In other words, the terminal can assume the channel parameters used when receiving the candidate beam RS corresponding to the PRACH transmitted by the terminal when receiving the PDCCH and PDSCH.The terminal may apply the assumption that the same channel parameters as the candidate beam RS reception are applied when receiving the PDCCH and PDSCH until it receives activation for the TCI state from the upper layer of the terminal, or receives the upper layer signaling tci-StatesPDCCH-ToAddList or tci-StatesPDCCH-ToReleaseList or both (13-20). The terminal may use the changed TCI state when receiving the PDCCH after it receives activation for the TCI state from the upper layer of the terminal, or receives the upper layer signaling tci-StatesPDCCH-ToAddList or tci-StatesPDCCH-ToReleaseList or both (13-25). After the terminal receives a PDCCH including a CRC scrambled with C-RNTI or MCS-C-RNTI in a search space having recoverySearchSpaceId, the terminal may monitor PDCCH candidates in the search space having recoverySearchSpaceId until it receives a MAC-CE for TCI state activation or receives a higher layer signaling tci-StatesPDCCH-ToAddList or tci-StatesPDCCH-ToReleaseList.

[0339] In PCell or PSCell, from the last symbol of the first PDCCH reception (13-30) of which the UE has a recoverySearchSpaceId, and after 28 symbols (13-35) until the UE receives MAC-CE for activating PUCCH-SpatialRelationInfo or receives PUCCH-SpatialRelationInfo, which is an upper layer signaling for a specific PUCCH resource (13-40), the UE may use the same spatial filter (13-45) as the most recently transmitted PRACH when transmitting a PUCCH in the same cell (13-46), use index 0 as p0 as a power control parameter, use candidate beam RS used in the BFRQ above as a path loss reference signal, and use 0 as a power control closed loop index (13-50). After the terminal receives MAC-CE for PUCCH-SpatialRelationInfo activation or receives PUCCH-SpatialRelationInfo, which is an upper layer signaling for a specific PUCCH resource, the terminal can use spatial filter and power control parameters based on the changed PUCCH-SpatialRelationInfo when transmitting PUCCH (37-55).

[0340] In PCell or PSCell, from the last symbol of the first PDCCH reception containing CRC scrambled with C-RNTI or MCS-C-RNTI in the search space where the UE has recoverySearchSpaceId (13-35), the UE may apply the assumption that it has the same QCL parameters as the candidate beam RS reception when monitoring the PDCCH in control resource set 0 (13-60).

[0341] If the terminal receives TCI-State_r17, which is an upper layer signaling that means that the terminal operates in the integrated TCI mode, in the PCell or PSCell, and the terminal receives the first PDCCH containing a CRC scrambled with C-RNTI or MCS-C-RNTI in the search space having recoverySearchSpaceId, the terminal can perform the following operations after 28 symbols from the last symbol.

[0342] - If the terminal has not been configured with the upper layer signaling SSB-MTC-AdditionalPCI, the terminal may apply the assumption that it has the same QCL parameters as the candidate beam RS reception when monitoring all control resource sets, receiving PDSCH, and receiving aperiodic CSI-RS resources. In this case, the aperiodic CSI-RS resource may be included in a CSI-RS resource set that can be received in the same TCI state as PDCCH and PDSCH, since a dynamically indicated integrated TCI state may be applied.

[0343] - When transmitting PUSCH, PUCCH, and SRS, the terminal may use the spatial domain filter used for the most recently transmitted PRACH. At this time, the SRS may be transmitted using the same spatial domain filter as the PUSCH and PUCCH, as the dynamically indicated integrated TCI state may be applied. The power control parameters for PUSCH, PUCCH, and SRS transmission by the terminal may follow the following.

[0344] ■ The path loss reference signal can follow the above candidate beam RS and use it to measure the downlink path loss value.

[0345] ■ As a power control parameter for PUSCH transmission, the p0, alpha, PUSCH power control adjustment states included in p0-Alpha-CLID-PUSCH-Set associated with the ul-powercontrolId with the lowest value in PCell or PSCell can be used.

[0346] ■ As a power control parameter for PUCCH transmission, the p0, alpha, PUCCH power control adjustment states included in p0-Alpha-CLID-PUCCH-Set associated with the ul-powercontrolId with the lowest value in PCell or PSCell can be used.

[0347] ■ As a power control parameter for SRS transmission, the p0, alpha, SRS power control adjustment states included in p0-Alpha-CLID-SRS-Set associated with the lowest value of ul-powercontrolId in PCell or PSCell can be used.

[0348] [Rel-16 SCell BFR]

[0349] Next, we detail beam failure recovery (BFR) operations in secondary cells (SCells). If the base station and UE reuse BFR operations for the PCell, which have already been defined for the SCell, the following additional considerations may apply.

[0350] - [SCell Consideration 1] When one or more SCells are DL-only cells

[0351] - [SCell Consideration 2] If one or more SCells do not contain the control resource set, search space, or both.

[0352] - [SCell Consideration 3] If there are multiple SCells and a beam failure occurs in one or more of them

[0353] In the case of the above [SCell Consideration 1], if the terminal reuses the PCell BFR, when a beam failure occurs in a specific SCell, the terminal may not be able to perform PRACH transmission for beam failure recovery request (BFRQ) transmission to the base station in the SCell. Therefore, a method for reporting the beam failure situation for the SCell to the base station from another cell capable of uplink transmission may be required.

[0354] In the case of the above [SCell Consideration 2], if the terminal reuses the PCell BFR, when a beam failure occurs in a specific SCell, the terminal cannot receive the base station's response to the BFRQ through the recovery search space from the base station in the SCell. Therefore, a method of receiving a response from the base station in another cell where a control resource set and search space exist may be required.

[0355] In the case of the above [SCell Consideration 3], if the UE reuses the PCell BFR, when beam failure occurs in at least one specific SCell, the UE may have to perform PRACH transmission for each SCell, which may cause a large signaling overhead burden on the UE. In addition, if a large number of SCells experience beam failure, a long delay may occur when transmitting BFRQ from the UE to the base station. Therefore, a method that considers the signaling overhead when performing BFRQ for multiple SCells may be required.

[0356] With the above considerations in mind, NR release 16 defines the BFR operation for SCells. The difference from the existing PCell BFR may be the BFRQ process and the corresponding base station response process, and the BFD RS set may be configured by upper layer signaling in the downlink bandwidth portion within each SCell, or if not configured, the BFD RS set may include some or all of the RSs referenced in the activated TCI state of the CORESET(s) configured for PDCCH monitoring of the UE within the corresponding downlink bandwidth portion, and the candidate beam RS set may be configured in the upper layer signaling BeamFailureRecoverySCellConfig in the downlink bandwidth portion within each SCell. The UE may receive schedulingRequestID-BFR-SCell, which is an upper layer signaling, from the base station, which may be upper layer signaling configuration information for PUCCH transmission for link recovery request (LRR).

[0357] FIG. 14 is a diagram illustrating a process of a base station responding to a BFR request signal of a terminal in a SCell BFR operation according to an embodiment of the present disclosure. The terminal can transmit a PUCCH resource having a value of schedulingRequestID-BFR-SCell to the base station as a scheduling request signal (14-00). As a response of the base station to the scheduling request PUCCH, the terminal can receive a first PDCCH from the base station (14-05), and can receive first PUSCH scheduling information through the first PDCCH. Based on the scheduling information, the terminal can transmit a BFR MAC-CE included in the first PUSCH (14-10). The BFR MAC-CE can include an SCell index having a radio link quality lower than a reference value, whether a candidate beam RS exists for the SCells, and if so, a candidate beam RS index identified in the SCell. For example, the BFR MAC-CE included in the first PUSCH may include indices 1 and 2 for SCells having a radio link quality lower than a reference value, a candidate beam RS index 10 for the first SCell, and a candidate beam RS index 15 for the second SCell (14-11). After the first PUSCH transmission, the terminal may receive a second PDCCH from the base station (14-15), and the second PDCCH may have the same HARQ process ID field value as the first PDCCH and may include a toggled NDI field value. The terminal may perform the following operation from 28 symbols after the last symbol of the second PDCCH reception from the base station (14-20).The subcarrier spacing of the above 28 symbols can be determined as the smallest subcarrier spacing between the activated downlink bandwidth portion in which the PDCCH is received and the activated downlink bandwidth portion within at least one SCell.

[0358] - When the terminal monitors the control resource set within one or more SCells whose index is included in the BFR MAC-CE, if candidate beam RS information for each SCell within the BFR MAC-CE is included, the terminal can assume the same QCL parameters as the candidate beam RS. That is, when monitoring the control resource set in each SCell, the terminal can assume the channel parameters used when receiving the candidate beam RS for each SCell within the BFR MAC-CE.

[0359] - When transmitting a PUCCH on a PUCCH SCell, the terminal may use a spatial domain filter corresponding to the candidate beam RS included in the BFR MAC-CE for the corresponding SCell and reported to the base station, and p0 may use index 0 as the power control parameter, the path loss reference signal may use the candidate beam RS, and the power control closed loop index may use 0. The conditions at this time may be as follows.

[0360] ■ The terminal has set or activated PUCCH-SpatialRelationInfo from the base station for the corresponding PUCCH,

[0361] ■ PUCCH for the above LRR was not transmitted or was transmitted to PCell or PSCell,

[0362] ■ When the PUCCH SCell index is included in the BFR MAC-CE

[0363] For example, if the first SCell included in the BFR MAC-CE is a PUCCH-SCell, the terminal can assume QCL parameters such as candidate beam RS #10 when monitoring all control resource sets in the first SCell, the terminal can use a spatial domain filter corresponding to candidate beam RS #10 when transmitting PUCCH in the first SCell, use index 0 as p0 as a power control parameter, use candidate beam RS #10 as a path loss reference signal, and use 0 as a power control closed loop index (14-25). In addition, the terminal can assume QCL parameters such as candidate beam RS #15 when monitoring all control resource sets in the second SCell (14-30).

[0364] If the terminal receives TCI-State_r17, dl-OrJoint-TCIStateList or TCI-UL-State, which are upper layer signalings meaning that the terminal operates in an integrated TCI mode, in the PCell or PSCell, and after the first PUSCH transmission including BFR MAC-CE, the terminal can receive the second PDCCH from the base station as described above, and the second PDCCH can have the same HARQ process ID field value as the first PDCCH and can include a toggled NDI field value. The terminal can perform the following operation from 28 symbols after the last symbol of the second PDCCH reception from the base station.

[0365] - The terminal may apply the assumption that it has the same QCL parameters as the candidate beam RS reception when monitoring all control resource sets, receiving PDSCH, and receiving aperiodic CSI-RS resources. In this case, the aperiodic CSI-RS resource may be included in a CSI-RS resource set that can be received in the same TCI state as the PDCCH and PDSCH, since a dynamically indicated integrated TCI state may be applied.

[0366] - When transmitting PUSCH, PUCCH, and SRS, the terminal may use the spatial domain filter used when receiving the candidate beam RS. At this time, the SRS may be transmitted using the same spatial domain filter as PUSCH and PUCCH because a dynamically indicated integrated TCI state may be applied. The power control parameters when the terminal transmits PUSCH, PUCCH, and SRS may follow the following.

[0367] ■ The path loss reference signal can follow the above candidate beam RS and use it to measure the downlink path loss value.

[0368] ■ As a power control parameter for PUSCH transmission, the p0, alpha, PUSCH power control adjustment states included in the p0-Alpha-CLID-PUSCH-Set associated with the ul-powercontrolId with the lowest value in the corresponding SCell can be used.

[0369] ■ As a power control parameter for PUCCH transmission, the p0, alpha, PUCCH power control adjustment states included in p0-Alpha-CLID-PUCCH-Set associated with the ul-powercontrolId with the lowest value in the corresponding SCell can be used.

[0370] ■ As a power control parameter for SRS transmission, the p0, alpha, SRS power control adjustment states included in the p0-Alpha-CLID-SRS-Set associated with the ul-powercontrolId with the lowest value in the corresponding SCell can be used.

[0371] In PCell or PSCell, if BFR MAC-CE is transmitted through Msg3 or MsgA in a contention-based random access procedure, and the UE has set or activated PUCCH-spatialrelationinfo for a PUCCH resource from the base station, the UE can transmit the corresponding PUCCH resource 28 symbols after receiving the PDCCH as a completion step of the contention-based random access procedure.

[0372] If the upper layer signaling TCI-State_r17, dl-OrJoint-TCIStateList or TCI-UL-State, which means that the terminal operates in the integrated TCI mode, is set to PCell or PSCell, and if BFR MAC-CE is transmitted through Msg3 or MsgA in the contention-based random access process, and the terminal has PUCCH-spatialrelationinfo set or activated for a certain PUCCH resource from the base station, after 28 symbols after the terminal receives PDCCH as the completion step of the contention-based random access process, the terminal may perform the following operations.

[0373] - If the terminal has not been configured with the upper layer signaling SSB-MTC-AdditionalPCI, the terminal may apply the assumption that it has the same QCL parameters as the candidate beam RS reception when monitoring all control resource sets, receiving PDSCH, and receiving aperiodic CSI-RS resources. In this case, the aperiodic CSI-RS resource may be included in a CSI-RS resource set that can be received in the same TCI state as PDCCH and PDSCH, since a dynamically indicated integrated TCI state may be applied.

[0374] - When transmitting PUSCH, PUCCH, and SRS, the terminal may use the spatial domain filter used for the most recently transmitted PRACH. At this time, the SRS may be transmitted using the same spatial domain filter as the PUSCH and PUCCH, as the dynamically indicated integrated TCI state may be applied. The power control parameters for PUSCH, PUCCH, and SRS transmission by the terminal may follow the following.

[0375] ■ The path loss reference signal can follow the above candidate beam RS and use it to measure the downlink path loss value.

[0376] ■ As a power control parameter for PUSCH transmission, the p0, alpha, PUSCH power control adjustment states included in p0-Alpha-CLID-PUSCH-Set associated with the ul-powercontrolId with the lowest value in PCell or PSCell can be used.

[0377] ■ As a power control parameter for PUCCH transmission, the p0, alpha, PUCCH power control adjustment states included in p0-Alpha-CLID-PUCCH-Set associated with the lowest value of ul-powercontrolId in PCell or PSCell can be used.

[0378] ■ As a power control parameter for SRS transmission, the p0, alpha, SRS power control adjustment states included in p0-Alpha-CLID-SRS-Set associated with the lowest value of ul-powercontrolId in PCell or PSCell can be used.

[0379] FIG. 15A and FIG. 15B are diagrams illustrating the structure of a BFR MAC-CE according to an embodiment of the present disclosure. FIG. 15A and FIG. 15B include a BFR MAC-CE and a Truncated BFR MAC-CE. The BFR MAC-CE and the Truncated BFR MAC-CE can be distinguished through a MAC subheader including an LCID / eLCID.

[0380] BFR MAC-CE and Truncated BFR MAC-CE can have variable sizes. Both MAC-CE structures can include bitmaps for cell indices expressed in ascending order according to the ServCellIndex value, which is an upper layer signaling, and can contain candidate beam information for the cell corresponding to each bit position in the bitmap. For BFR MAC-CE, if a beam failure is confirmed and the value of the largest ServCellIndex among the cells for which performance evaluations for multiple candidate beams have been completed is less than 8, a bitmap for a cell index corresponding to one octet is used (15-00). Otherwise (i.e., if a beam failure is confirmed and the value of the largest ServCellIndex among the cells for which performance evaluations for multiple candidate beams have been completed is greater than or equal to 8), a bitmap for a cell index corresponding to four octets can be used (15-50). One MAC PDU can contain at most one BFR MAC-CE.

[0381] For Truncated BFR MAC-CE, a bitmap for a cell index corresponding to one octet may be used in the following cases (15-00), otherwise a bitmap for a cell index corresponding to four octets may be used (15-50).

[0382] - If beam failure is confirmed and the value of the largest ServCellIndex among the cells for which performance evaluation for multiple candidate beams has been completed is less than 8, or

[0383] - If a beam failure is identified in SpCell, and the SpCell is contained within the Truncated BFR MAC-CE, and the available UL-SCH resources cannot accommodate the combined length of the bitmap and subheader for the cell index corresponding to 4 octets due to LCP.

[0384] The description for each field may be as follows:

[0385] - SP: This field can indicate information about beam failure in SpCell. This field can be set to 1 when beam failure is confirmed in SpCell, if BFR MAC-CE or Truncated BFR MAC-CE is included in the MAC PDU during the random access process. Otherwise, it can be set to 0.

[0386] - C i (BFR MAC-CE): This field can indicate information about beam failure and can determine the existence of an octet corresponding to ServCellIndex whose value is i. If this field is set to 1, it may mean that beam failure has been confirmed in ServCellIndex whose value is i, performance evaluations for multiple candidate beams in the corresponding cell have been completed, and there is an octet corresponding to this. The octet may have an AC field and a candidate RS ID field. If this field is set to 0, it may mean that beam failure has not been confirmed in ServCellIndex whose value is i, or even if beam failure has been confirmed, performance evaluations for multiple candidate beams in the corresponding cell have not been completed, and there is no octet corresponding to this. Each C i- Each octet corresponding to a value can be arranged in ascending order of the i value.

[0387] - Ci (Truncated BFR MAC-CE): This field can indicate information about beam failure and can determine the existence of an octet corresponding to ServCellIndex whose value is i. If this field is set to 1, it may mean that beam failure has been confirmed in ServCellIndex whose value is i and performance evaluations for multiple candidate beams in the corresponding cell have been completed. The corresponding octet may or may not exist, and if it exists, the corresponding octet may have an AC field and a candidate RS ID field. If this field is set to 0, it may mean that beam failure has not been confirmed in ServCellIndex whose value is i, or even if beam failure has been confirmed, performance evaluations for multiple candidate beams in the corresponding cell have not been completed and the corresponding octet does not exist. Each C i- Each octet corresponding to a value may be arranged in ascending order of the i value, if any, and the number of octets containing AC fields may be maximized without exceeding the available grant size. There may be no octets containing AC fields in a Truncated BFR MAC-CE.

[0388] - AC: This field may indicate whether the candidate RS ID field of the corresponding octet exists. If at least one SSB among the multiple SSBs in the upper layer signaling candidateBeamRSSCellList has an SS-RSRP value exceeding the reference value rsrp-ThresholdBFR, or if at least one CSI-RS among the multiple CSI-RSs in the upper layer signaling candidateBeamRSSCellList has a CSI-RSRP value exceeding the reference value rsrp-ThresholdBFR, this field may be indicated as 1. Otherwise, this field may be indicated as 0. If this field is indicated as 1, the Candidate RS ID field in the same octet may exist, and if this field is indicated as 0, the Candidate RS ID field in the same octet may not exist, and a reserved bit may exist instead.

[0389] - Candidate RS ID: This field may indicate the index of an SSB having an SS-RSRP value exceeding the reference value rsrp-ThresholdBFR among multiple SSBs in the upper layer signaling candidateBeamRSSCellList, or the index of a CSI-RS having a CSI-RSRP value exceeding the reference value rsrp-ThresholdBFR among multiple CSI-RSs in the upper layer signaling candidateBeamRSSCellList. The index of the SSB or CSI-RS may indicate the index of the entry order in the upper layer signaling candidateBeamRSSCellList. Indexes 0 and 1 may indicate the RS of the first and second entries in the candidateBeamRSSCellList. This field may consist of 6 bits.

[0390] [Rel-17 per-TRP BFR]

[0391] Next, we will describe the beam failure recovery operation for each TRP in detail. In the current NR system, a BFD RS set can include up to two RSs, while a maximum of three CORESETs configured for PDCCH monitoring of the UE can be configured per bandwidth segment. Furthermore, in Release 16 NR systems, the maximum number of CORESETs per bandwidth segment was increased to five for multiple PDCCH-based multi-TRP transmissions, and there was discussion about increasing the maximum number of CORESETs per bandwidth segment to support wideband operation in Release 16 NR-U. Therefore, if, as in the conventional BFD operation, a virtual PDCCH reception BLER is calculated for all RSs in the BFD RS set and all BLER values ​​must exceed a threshold before a beam failure indication is reported to the upper layer, the delay time until the remaining BFR process can be increased, and situations where only the BLER value for a specific RS in the BFD RS set exceeds the threshold cannot be detected. Accordingly, when a BFD RS set is not set to a terminal through upper layer signaling, a beam failure indication can be made with only some of the RSs in the BFD RS set selected from among the RSs referenced in the activated TCI state of the CORESET(s) set for PDCCH monitoring of the terminal, or multiple BFD RS sets can be set to the terminal through upper layer signaling, or the base station can instruct the terminal to arbitrarily select multiple BFD RS sets, thereby increasing the efficiency of the BFD process for determining whether smooth downlink transmission is possible between the base station and the terminal, thereby enabling the performance of a BFR procedure with low delay.

[0392] In addition, since the BFR procedure of the current NR system is designed without considering the operation of multi-TRP / panels of the base station, when the base station operates multi-TRP / panels, the BFR procedure can be performed more efficiently by utilizing each link between the multi-TRP / panels of the base station and the terminal, rather than operating according to the existing BFR procedure. For example, if one RS in the BFD RS set is associated with the first TRP, and the remaining one RS is associated with the second TRP, and the link between the terminal and TRP1 is good while the link between the terminal and TRP2 is degraded, the virtual BLER for the RS associated with TRP1 may still be calculated as good, making it impossible to perform the beam failure recovery operation. In addition, if the link between the terminal and a TRP or panel that is not experiencing beam failure among the multi-TRP / panels connected to the terminal is utilized, the BFR for the link between the terminal and the TRP or panel that is experiencing beam failure can be recovered within a low latency time. Among the embodiments of the present disclosure, the simplification of the BFR procedure considering multiple links of the above multi-TRP / panel is not limited to multi-TRP / panel, and can be equally applied in a single-TRP / panel situation in an environment where multiple BFD RS sets are defined and BFR is performed for each BFD RS set.

[0393] Instead of one BFD RS set and one candidate beam RS set, the terminal can be configured with two BFD RS sets and two candidate beam RS sets. The first BFD RS set is connected to the first candidate beam RS set, and the second BFD RS set is connected to the second candidate beam RS set. The terminal can be configured with the first and second BFD RS sets through upper layer signaling, failureDetectionSet1 and failureDetectionSet2, from the base station. If the terminal does not receive the configuration for the first and second BFD RS sets from the base station through the upper layer signaling, failureDetectionSet1 and failureDetectionSet2, the terminal may include some or all of the RSs referenced in the activated TCI state of one or more first CORESETs, in which the upper layer signaling, coresetPoolIndex, is set to 0 or the coresetPoolIndex value is not set, in the first BFD RS set, and the terminal may include some or all of the RSs referenced in the activated TCI state of one or more second CORESETs, in which the upper layer signaling, coresetPoolIndex, is set to 1, in the second BFD RS set.

[0394] The terminal can report to the base station as terminal capability information the maximum number of RSs per BFD RS set and the maximum value of the total number of RSs included in the two BFD RS sets, and based on this terminal capability information, if the terminal is configured for the first and second BFD RS sets by upper layer signaling as described above, or if the terminal is not configured, if the first and second BFD RS sets are configured using some or all of the RSs referenced in the TCI state activated in the first and second CORESETs, the terminal can expect the number of RSs per BFD RS set and the total number of RSs included in the two BFD RS sets to be less than or equal to the terminal capability value reported to the base station. If the terminal has not received the configuration for the first and second BFD RS sets from the base station through the upper layer signaling, failureDetectionSet1 and failureDetectionSet2, and the total number of RSs referenced in the TCI states activated in the first and second CORESETs is greater than the maximum value of the total number of RSs included in the two BFD RS sets reported by the terminal capability, the terminal may select an RS referenced in the TCI state activated in a CORESET with a shorter search space period among the plurality of first and second CORESETs. If the search spaces connected to the plurality of first and second CORESETs have the same period, the terminal may select an RS referenced in the TCI state activated in a CORESET with a larger index.

[0395] If the terminal

[0396] - Contains one or more first CORESETs that have not received upper layer signaling coresetPoolIndex within the activated downlink bandwidth portion of a serving cell or have the coresetPoolIndex value set to 0;

[0397] - Contains one or more second CORESETs with the upper layer signaling coresetPooIndex value set to 1 within the same activated downlink bandwidth portion within the same serving cell,

[0398] - If the upper layer signaling SSB-MTCAdditionalPCI is set,

[0399] The terminal may include an SSB index associated with a physical cell ID different from the physCellId value in ServingCellConfigCommon, which is an upper layer signaling, in the first or second candidate beam RS set, and may also consider the first or second BFD RS set associated therewith to be associated with the same physical cell ID. For example, if the physCellId value in ServingCellConfigCommon is 0 and a specific SSB is associated with a physical cell ID value of 1, the terminal may consider the first BFD RS set and the first candidate beam RS set to be associated with 0, which is the physical cell ID of the serving cell, and the second BFD RS set and the second candidate beam RS set to be associated with 1, which is the physical cell ID to which the corresponding SSB is associated.

[0400] If the PCell and the PSCell are connected to the first BFD RS set and the first candidate beam RS set connected thereto, and the second BFD RS set and the second candidate beam RS set connected thereto, the UE can report to the base station that there are two LRRs that can be configured by upper layer signaling from the base station through the UE capability report twoLRRcapacity, and a UE that has not reported this can receive configuration information for the first LRR from the base station through the upper layer signaling schedulingRequestID-BFR, and if the UE has reported this, the UE can additionally receive configuration information for the second LRR from the base station through the upper layer signaling schedulingRequestID-BFR2. If the UE has received only the configuration for the first LRR from the base station through the upper layer signaling, the UE can perform PUCCH transmission for the LRRs for the first and second BFD RS sets. If the terminal receives configuration information for the first and second LRRs from the base station through upper layer signaling, the terminal can use the configuration information for the first LRR for the first BFD RS set, and can use the configuration information for the second LRR for the second BFD RS set.

[0401] If at least one serving cell is connected to the first BFD RS set and the first candidate beam RS set connected thereto, and the second BFD RS set and the second candidate beam RS set connected thereto, the terminal may transmit a second PUSCH including an enhanced BFR MAC-CE to the base station. At this time, the enhanced BFR MAC-CE may include at least one of the following pieces of information.

[0402] - Cell index(es) corresponding to a single BFD RS set with a link quality lower than the reference value

[0403] - Whether the selected candidate beam RS exists in each single candidate beam RS set within the cell index(es) corresponding to the single BFD RS set above, and if so, the index of the candidate beam RS.

[0404] - Cell index(es) in which at least one of the first and second BFD RS sets has a link quality lower than the reference value.

[0405] ■ BFD RS set index(es) with link quality lower than the reference value among the first and second BFD RS sets

[0406] - Whether a selected candidate beam RS exists in each of the first and second candidate beam RS sets within the cell index(es) corresponding to the first and second BFD RS sets, and if so, the index of the candidate beam RS for each set.

[0407] For serving cell(s) connected to a first BFD RS set and a first candidate beam RS set connected thereto, a second BFD RS set and a second candidate beam RS set connected thereto, after 28 symbols from the last symbol of reception of a 2-1 PDCCH including the same HARQ process ID field and toggled NDI field value as the 1-1 PDCCH that scheduled the second PUSCH, the terminal may perform the following operation. At this time, the subcarrier spacing for the 28 symbols may be determined as the smallest subcarrier spacing among the activated downlink bandwidth portion for receiving the PDCCH and the activated downlink bandwidth portions of the serving cells.

[0408] - When the terminal monitors the first CORESET in which the upper layer signaling coresetPoolIndex is not set or coresetPoolIndex is set to 0, the terminal may follow the QCL parameter assumption of the candidate beam RS selected from the first candidate beam RS set.

[0409] - When monitoring the second CORESET in which the upper layer signaling coresetPoolIndex is set to 1, the terminal may follow the QCL parameter assumption of the candidate beam RS selected from the second candidate beam RS set.

[0410] FIG. 16 is a diagram illustrating a process of a base station responding to a BFR request signal of a terminal in a BFR operation by TRP according to an embodiment of the present disclosure. The terminal may receive one or two pieces of LRR configuration information according to the terminal capability report and the corresponding upper layer signaling of the base station, and may transmit a PUCCH for the selected LRR to the base station depending on which of the first and second BFD RS sets is in a beam failure situation and performs a BFRQ operation in response thereto (16-00). As a response of the base station, the terminal may receive a 1-1 PDCCH including the second PUSCH scheduling information from the base station (16-05). Based on the corresponding second PUSCH scheduling information, the terminal may transmit a second PUSCH including an enhanced BFR MAC-CE to the base station (16-10). For example, the enhanced BFR MAC-CE may include the following information (16-11).

[0411] - SCell Index: #1, associated with multiple BFD RS sets

[0412] ■ BFD RS set with virtual BLER lower than the reference value: First BFD RS set in SCell#1

[0413] ■ In the first candidate beam RS set connected to the first BFD RS set in SCell#1, there is a candidate beam RS selected by a terminal having a link quality higher than the reference value, and the index of the RS is: #5.

[0414] - SCell Index: #2, associated with multiple BFD RS sets

[0415] ■ BFD RS sets with virtual BLER lower than the reference value: 1st and 2nd BFD RS sets in SCell#2

[0416] ■ In the first candidate beam RS set connected to the first BFD RS set in SCell#2, there is a candidate beam RS selected by a terminal having a link quality higher than the reference value, and the index of the RS is: #10.

[0417] ■ In the second candidate beam RS set connected to the second BFD RS set in SCell#2, there is a candidate beam RS selected by a terminal with a link quality higher than the reference value, and the index of the RS is: #15.

[0418] After 28 symbols (16-20) from the last symbol of the 2-1 PDCCH reception (16-15), which includes the same HARQ process ID field and toggled NDI field value as the 1-1 PDCCH that scheduled the above-mentioned 2 PUSCH, the terminal can perform the following operation.

[0419] - In SCell#1,

[0420] ■ When the terminal monitors the first CORESET in which the upper layer signaling coresetPoolIndex is not set or coresetPoolIndex is set to 0, the terminal may follow the QCL parameter assumption of candidate beam RS#5 selected from the first candidate beam RS set (16-25).

[0421] ■ When the terminal monitors the second CORESET with the upper layer signaling coresetPoolIndex set to 1, the second BFD RS set within the cell is not reported as a BFD RS set with a virtual BLER lower than the reference value through the enhanced BFR MAC-CE, so it is determined that it is not a beam failure situation, and therefore the terminal can monitor using the TCI state previously set or activated in the second CORESET (16-30).

[0422] - In SCell#2,

[0423] ■ When the terminal monitors the first CORESET in which the upper layer signaling coresetPoolIndex is not set or coresetPoolIndex is set to 0, the terminal may follow the QCL parameter assumption of candidate beam RS#10 selected from the first candidate beam RS set (16-35).

[0424] ■ When monitoring the second CORESET in which the upper layer signaling coresetPoolIndex is set to 1, the terminal can follow the QCL parameter assumption of candidate beam RS#15 selected from the second candidate beam RS set (16-40).

[0425] FIGS. 17A and 17B are diagrams illustrating the structure of an enhanced BFR MAC-CE according to an embodiment of the present disclosure. FIGS. 17A and 17B include an enhanced BFR MAC-CE and a truncated enhanced BFR MAC-CE. The enhanced BFR MAC-CE and the truncated enhanced BFR MAC-CE can be distinguished through a MAC subheader including an LCID / eLCID.

[0426] The enhanced BFR MAC-CE and the Truncated enhanced BFR MAC-CE can have variable sizes. Both MAC-CE structures have an SP field, C i Bitmap (represented as 1 or 4 octets), S j A bitmap (expressed as 0 to 4 octets), first beam failure recovery information (for an SpCell containing two BFD RS sets, an AC field indicating whether candidate beams are available for each of one or two BFD RS sets), and second beam failure recovery information (C i For SCells represented as bitmaps, an AC field indicating candidate beam availability for each of one or two BFD RS sets may be included, with information expressed in ascending order of ServCellIndex.

[0427] For Enhanced BFR MAC-CE, C corresponds to one octet in the following cases: i A bitmap is used (17-00), otherwise a C equivalent of 4 octets i Bitmaps may be used (17-50). A MAC PDU may contain a MAC-CE for at most one BFR.

[0428] - In certain SCells connected to a single BFD RS set, beam failure is confirmed and the value of the largest ServCellIndex among the cells for which performance evaluation for multiple candidate beams has been completed is less than 8, or

[0429] - In specific SCells connected to two BFD RS sets, if beam failure is confirmed for at least one BFD RS set and the value of the largest ServCellIndex among cells for which performance evaluation for multiple candidate beams has been completed is less than 8.

[0430] For truncated enhanced BFR MAC-CE, a bitmap for a cell index corresponding to one octet may be used in the following cases (17-00), otherwise a bitmap for a cell index corresponding to four octets may be used (17-50).

[0431] - In certain SCells connected to a single BFD RS set, beam failure is confirmed and the value of the largest ServCellIndex among the cells for which performance evaluation for multiple candidate beams has been completed is less than 8, or

[0432] - In specific SCells connected to two BFD RS sets, if beam failure is confirmed for at least one BFD RS set and the value of the largest ServCellIndex among cells for which performance evaluation for multiple candidate beams has been completed is less than 8.

[0433] - If a beam failure is detected in the SpCell, and the SpCell does not contain two BFD RS sets, and the SpCell is contained within the Truncated BFR MAC-CE, and the available UL-SCH resources cannot accommodate the combined length of the bitmap and subheader for the cell index corresponding to four octets due to LCP.

[0434] - When a random access process is initiated for a BFR process for two BFD RS sets within a SpCell, and the SpCell contains two BFD RS sets, and the SpCell is contained within the Truncated BFR MAC-CE, and the available UL-SCH resources cannot accommodate the combined length of the bitmap and subheader for the cell index corresponding to four octets due to LCP.

[0435] For the Enhanced BFR MAC-CE and Truncated enhanced BFR MAC-CE, the above S k A bitmap can have octets of the following lengths, depending on the following conditions:

[0436] - If it contains two BFD RS sets, and the SP or C i If the number of serving cells with field 1 is greater than 0 and less than 9, S k A bitmap can be represented by one octet.

[0437] - If it contains two BFD RS sets, and the SP or C i If the number of serving cells with field 1 is greater than 8 and less than 17, S k A bitmap can be represented by two octets.

[0438] - If it contains two BFD RS sets, and the SP or C iIf the number of serving cells with field 1 is greater than 16 and less than 25, S k A bitmap can be represented by three octets.

[0439] - If it contains two BFD RS sets, and the SP or C i If the number of serving cells with field 1 is greater than 24, S k A bitmap can be represented by four octets.

[0440] - If it contains two BFD RS sets, and the SP or C i If there are no serving cells with field 1, S k Bitmaps may not be included.

[0441] For a truncated enhanced BFR MAC-CE, an octet containing an AC field may be present first for an SpCell, and then for each SCell in ascending order, maximizing the number of octets containing AC fields within the available grant size. There may be no octets containing AC fields within a truncated enhanced BFR MAC-CE.

[0442] The description for each field may be as follows:

[0443] - SP (enhanced BFR MAC-CE): This field can indicate information about beam failure detection in the SpCell, and if the SpCell contains multiple BFD RS sets, it can indicate the presence of one or more octets containing AC fields. For a SpCell containing multiple BFD RS sets, setting this field to 1 can mean that beam failure was detected in at least one BFD RS set in the SpCell, performance evaluation for multiple candidate beams has been completed, and one or more octets containing AC fields are present. Otherwise, this field can be set to 0. For a SpCell, one or more octets containing AC fields can be present before the octets for SCells. For a SpCell containing a single BFD RS set, setting this field to 1 can mean that beam failure is detected in the SpCell when enhanced BFR MAC-CE is included in the MAC PDU during the random access procedure. Otherwise, it can be indicated as 0.

[0444] - SP (truncated enhanced BFR MAC-CE): This field may indicate information about beam failure in the SpCell. For a SpCell containing multiple BFD RS sets, setting this field to 1 may mean that beam failure was detected in at least one BFD RS set in the SpCell, performance evaluation for multiple candidate beams was completed, and one or more octets containing AC fields may or may not be present. Otherwise, this field may be set to 0. For a SpCell containing a single BFD RS set, setting this field to 1 may mean that beam failure was detected in the SpCell if enhanced BFR MAC-CE was included in the MAC PDU during the random access procedure. Otherwise, it may be set to 0.

[0445] - C i(enhanced BFR MAC-CE): This field can indicate information about beam failure and can determine the presence of an octet in the SCell corresponding to the ServCellIndex whose value is i. If this field is set to 1, it may mean that beam failure has been confirmed for at least one BFD RS set in the SCell corresponding to the ServCellIndex whose value is i, and performance evaluations for multiple candidate beams in the corresponding cell have been completed, and that an octet corresponding to this exists, and the octet may have an AC field and a candidate RS ID field. If this field is set to 0, it may mean that beam failure has not been confirmed for any BFD RS set in the SCell corresponding to the ServCellIndex whose value is i, or that beam failure has been confirmed for at least one BFD RS set but performance evaluations for multiple candidate beams in the corresponding cell have not been completed, and that an octet corresponding to this does not exist. Each C i- Each octet corresponding to a value can be placed in ascending order of the i value and can be placed after the octet for SpCell.

[0446] - C i(Truncated BFR MAC-CE): This field can indicate information about beam failure and can determine the presence of an octet in the SCell corresponding to the ServCellIndex whose value is i. If this field is set to 1, it may mean that beam failure has been confirmed for at least one BFD RS set in the SCell corresponding to the ServCellIndex whose value is i, and performance evaluations for multiple candidate beams in the corresponding cell have been completed. The corresponding octet may or may not exist, and if it exists, the corresponding octet may have an AC field and a candidate RS ID field. If this field is set to 0, it may mean that beam failure has not been confirmed for any BFD RS set in the SCell corresponding to the ServCellIndex whose value is i, or that beam failure has been confirmed for at least one BFD RS set, but performance evaluations for multiple candidate beams in the corresponding cell have not been completed, and the corresponding octet does not exist. Each C i- Each octet corresponding to a value may be arranged in ascending order of the i value, if any, and the number of octets containing AC fields may be maximized without exceeding the available grant size. There may be no octets containing AC fields in a Truncated BFR MAC-CE.

[0447] - S k (enhanced BFR MAC-CE): This field is SP or C i The field is set to 1 and can correspond to the kth serving cell containing two BFD RS sets, SP or C. iThe field is set to 1, and multiple serving cells containing two BFD RS sets can be ordered in ascending order of the index of the SCell corresponding to the ServCellIndex whose value is i, starting from SpCell. This field can indicate whether a beam failure occurred for one BFD RS set or for both BFD RS sets for a particular serving cell, and whether one or two octets containing AC fields are present for the serving cell. S k A field value of 1 may mean that beam failures are detected for two BFD RS sets, that performance evaluations for multiple candidate beams are completed for both BFD RS sets, and that there are two octets containing AC fields for the corresponding serving cell. S k A field value of 0 may mean that a beam failure was detected for one of the two BFD RS sets and performance evaluations for multiple candidate beams were completed, or that a beam failure was detected for two BFD RS sets but performance evaluations for multiple candidate beams were not completed for both BFD RS sets, and that for the corresponding serving cell, there is one octet containing the AC field. S that are not mapped to any serving cell k A field can have a value of 0, which can be considered a cell that does not have two BFD RS sets.

[0448] - S k (truncated enhanced BFR MAC-CE): This field is SP or C iThe field is set to 1 and can correspond to the kth serving cell containing two BFD RS sets, SP or C. i The field is set to 1, and multiple serving cells containing two BFD RS sets can be ordered in ascending order of the index of the SCell corresponding to the ServCellIndex whose value is i, starting from SpCell. This field can indicate whether a beam failure occurred for one BFD RS set or for both BFD RS sets for a particular serving cell, and whether one or two octets containing AC fields are present for the serving cell. S k A field value of 1 may mean that beam failures are detected for two BFD RS sets, that performance evaluations for multiple candidate beams are completed for both BFD RS sets, and that there are 0, 1, or 2 octets containing AC fields for the corresponding serving cell. S k A field value of 0 may mean that a beam failure was detected for one of the two BFD RS sets and performance evaluations for multiple candidate beams were completed, or that a beam failure was detected for two BFD RS sets but performance evaluations for multiple candidate beams were not completed for both BFD RS sets, and that there are 0 or 1 octets containing the AC field for the corresponding serving cell. S that are not mapped to any serving cell k A field can have a value of 0, which can be considered a cell that does not have two BFD RS sets.

[0449] - AC: This field may indicate whether a candidate RS ID field of the corresponding octet exists. If at least one SSB among multiple SSBs in the list of candidate beams has an SS-RSRP value exceeding the reference value rsrp-ThresholdBFR, or if at least one CSI-RS among multiple CSI-RSs in the list of candidate beams has a CSI-RSRP value exceeding the reference value rsrp-ThresholdBFR, this field may be indicated as 1. Otherwise, this field may be indicated as 0. If this field is indicated as 1, the Candidate RS ID field in the same octet may exist, and if this field is indicated as 0, the Candidate RS ID field in the same octet may not exist, and a reserved bit may exist instead. The list of candidate beams above can use upper layer signaling candidateBeamRS-List-r16 for SCells where two BFD RS sets do not exist, and can use upper layer signaling candidateBeamRS-List-r16 and candidateBeamRS-List2-r17 for serving cells where two BFD RS sets exist.

[0450] - ID: This field may indicate the index of a BFD RS set. If this field has a value of 0, the corresponding octet may correspond to the first BFD RS set (i.e., it may correspond to the upper layer signaling failureDetectionSet1-r17), and if this field has a value of 1, the corresponding octet may correspond to the second BFD RS set (i.e., it may correspond to the upper layer signaling failureDetectionSet2-r17). For a serving cell that does not include two BFD RS sets, this field may have a value of 0.

[0451] - Candidate RS ID: This field may indicate the index of an SSB having an SS-RSRP value exceeding a reference value rsrp-ThresholdBFR among multiple SSBs in the list of candidate beams or the index of a CSI-RS having a CSI-RSRP value exceeding a reference value rsrp-ThresholdBFR among multiple CSI-RSs in the list of candidate beams. The index of the SSB or CSI-RS may indicate an index for the order of entries in the list of candidate beams. Indexes 0 and 1 may indicate the RS of the first and second entries in the list of candidate beams. This field may consist of 6 bits. The list of candidate beams above can use upper layer signaling candidateBeamRS-List-r16 for SCells where two BFD RS sets do not exist, and can use upper layer signaling candidateBeamRS-List-r16 and candidateBeamRS-List2-r17 for serving cells where two BFD RS sets exist.

[0452] [Distinguishing between Single-DCI-based Multi-TRP PDSCH Repetitive Transmission Techniques (TDM / FDM / SDM)]

[0453] Next, we describe a method for distinguishing between single-DCI-based multi-TRP PDSCH repetition transmission techniques. A UE may be instructed to use different single-DCI-based multi-TRP PDSCH repetition transmission techniques (e.g., TDM, FDM, SDM) based on values ​​indicated by a DCI field from a base station and higher-layer signaling configurations. Table 14 below illustrates a method for distinguishing between single- and multiple-TRP-based techniques indicated to a UE based on values ​​of specific DCI fields and higher-layer signaling configurations.

[0454] [Table 14]

[0455]

[0456] In the above [Table 14], each column can be explained as follows.

[0457] - Number of TCI states (2 columns): This refers to the number of TCI states indicated by the TCI state field in DCI, and can be 1 or 2.

[0458] - Number of CDM Groups (column 3): This indicates the number of different CDM groups of DMRS ports indicated by the Antenna port field in the DCI. It can be 1, 2, or 3.

[0459] - repetitionNumber setting and indication conditions (column 4): There are three conditions depending on whether repetitionNumber is set for all TDRA entries that can be indicated by the Time Domain Resource Allocation field in DCI and whether the actually indicated TDRA entry has repetitionNumber setting.

[0460] * Condition 1: At least one of all TDRA entries that can be indicated by the Time Domain Resource Allocation field contains a setting for repetitionNumber, and the TDRA entry indicated by the Time Domain Resource Allocation field in the DCI contains a setting for repetitionNumber greater than 1.

[0461] * Condition 2: At least one of all TDRA entries that can be indicated by the Time Domain Resource Allocation field contains a setting for repetitionNumber, and the TDRA entry indicated by the Time Domain Resource Allocation field in the DCI does not contain a setting for repetitionNumber.

[0462] * Condition 3: If all TDRA entries that can be indicated by the Time Domain Resource Allocation field do not contain a setting for repetitionNumber.

[0463] - RepetitionScheme setting related (column 5): This indicates whether the upper layer signaling repetitionScheme is set. The upper layer signaling repetitionScheme can be set to one of 'tdmSchemeA', 'fdmSchemeA', or 'fdmSchemeB'.

[0464] - Transmission technique indicated to the terminal (column 6): Refers to single or multiple TRP techniques indicated according to each combination (column 1) expressed in [Table 14] above.

[0465] * Single-TRP: This refers to a single TRP-based PDSCH transmission. If the UE has configured the pdsch-AggegationFactor in the upper layer signaling PDSCH-config, the UE can be scheduled for the configured number of repeated single-TRP-based PDSCH transmissions. Otherwise, the UE can be scheduled for a single single-TRP-based PDSCH transmission.

[0466] * Single-TRP TDM scheme B: This refers to PDSCH repeated transmission based on time resource division between single TRP slots. According to Condition 1 related to repetitionNumber described above, the UE repeatedly transmits PDSCH in the time dimension for the number of slots with repetitionNumber that is greater than 1 set in the TDRA entry indicated by the Time Domain Resource Allocation field. At this time, for each slot with repetitionNumber, the start symbol and symbol length of the PDSCH indicated by the TDRA entry are applied identically, and the same TCI state is applied for each PDSCH repeated transmission. This technique is similar to the slot aggregation method in that it performs PDSCH repeated transmission between slots on time resources, but it differs from slot aggregation in that it can dynamically determine whether to indicate repeated transmission based on the Time Domain Resource Allocation field in the DCI.

[0467] * Multi-TRP SDM: This refers to a PDSCH transmission method based on spatial resource division based on multiple TRPs. This is a method of receiving by dividing layers from each TRP. Although it is not a repetitive transmission method, it can increase the reliability of PDSCH transmission by increasing the number of layers and lowering the coding rate. The terminal can receive PDSCH by applying the two TCI states indicated through the TCI state field in the DCI for each of the two CDM groups indicated by the base station.

[0468] * Multi-TRP FDM scheme A: This refers to a multi-TRP based frequency resource division PDSCH transmission method. It has one PDSCH transmission position (occasion), so it is not repetitive transmission like multi-TRP SDM, but it is a technique that can transmit with high reliability by increasing the frequency resource amount and lowering the coding rate. Multi-TRP FDM scheme A can apply two TCI states indicated through the TCI state field in the DCI for non-overlapping frequency resources. If the PRB bundling size is determined as wideband, if the number of RBs indicated by the Frequency Domain Resource Allocation field is N, the terminal applies the first TCI state to the first ceil(N / 2) RBs and applies the second TCI state to the remaining floor(N / 2) RBs. Here, ceil(.) and floor(.) are operators that indicate rounding up and down to the first decimal place. If the PRB bundling size is determined as 2 or 4, even-numbered PRGs receive the first TCI state, and odd-numbered PRGs receive the second TCI state.

[0469] * Multi-TRP FDM scheme B: This refers to a multi-TRP based frequency resource division PDSCH repeated transmission method, and it has two PDSCH transmission positions (occasions) so that PDSCH can be repeatedly transmitted in each position. Multi-TRP FDM scheme B, like A, can apply two TCI states indicated through the TCI state field in the DCI to non-overlapping frequency resources. If the PRB bundling size is determined as wideband, if the number of RBs indicated by the Frequency Domain Resource Allocation field is N, the UE applies the first TCI state to the first ceil (N / 2) RBs and applies the second TCI state to the remaining floor (N / 2) RBs and receives them. Here, ceil (.) and floor (.) are operators indicating round up and down to the first decimal place. If the PRB bundling size is determined as 2 or 4, even-numbered PRGs receive the first TCI state, and odd-numbered PRGs receive the second TCI state.

[0470] * Multi-TRP TDM scheme A: This refers to a PDSCH repeated transmission method within a multi-TRP based time resource division slot. A terminal has two PDSCH transmission positions (occasions) within one slot, and the first reception position can be determined based on the starting symbol and symbol length of the PDSCH indicated through the Time Domain Resource Allocation field in the DCI. The starting symbol of the second reception position of the PDSCH can be a position that applies a symbol offset by the upper layer signaling StartingSymbolOffsetK from the last symbol of the first transmission position, and the transmission position can be determined by the indicated symbol length. If the upper layer signaling StartingSymbolOffsetK is not set, the symbol offset can be regarded as 0.

[0471] * Multi-TRP TDM scheme B: This refers to a PDSCH repeated transmission method between time resource division slots based on multiple TRPs. The UE has one PDSCH transmission position (occasion) in one slot, and can receive repeated transmissions based on the start symbol and symbol length of the same PDSCH for the number of slots indicated by the repetitionNumber through the Time Domain Resource Allocation field in the DCI. If the repetitionNumber is 2, the UE can receive the PDSCH repeated transmissions of the first and second slots by applying the first and second TCI states, respectively. If the repetitionNumber is greater than 2, the UE can use different TCI state application methods depending on how the upper layer signaling tciMapping is set. If tciMapping is set to cyclicMapping, the first and second TCI states are applied to the first and second PDSCH transmission positions, respectively, and the same TCI state application method is applied to the remaining PDSCH transmission positions. If tciMapping is set to sequentialMapping, the first TCI state is applied to the first and second PDSCH transmission positions, the second TCI state is applied to the third and fourth PDSCH transmission positions, and the same TCI state application method is applied to the remaining PDSCH transmission positions.

[0472] 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).

[0473] 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.

[0474] For convenience in the following description of the present disclosure, cells, transmission points, panels, beams, and / or transmission directions, which can be distinguished through upper layer / L1 parameters such as TCI state or spatial relation information, or indicators such as cell ID, TRP ID, and panel ID, may be uniformly described as TRP (transmission reception point), beam, or TCI state. Therefore, in actual application, TRP, beam, or TCI state can be appropriately replaced with one of the above terms.

[0475] 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.

[0476] 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 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 the embodiments of the present disclosure are described below using a 5G system as an example, the embodiments of the present disclosure may be applied to other communication systems having a similar technical background or channel type. For example, this may include LTE or LTE-A mobile communication and mobile communication technologies developed after 5G. Therefore, the embodiments of the present disclosure may be applied to other communication systems with some modifications without significantly departing from the scope of the present disclosure as determined by a person skilled in the art. The contents of the present disclosure can be applied to FDD and TDD systems.

[0477] 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.

[0478] 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.

[0479] - MIB (Master Information Block)

[0480] - SIB (System Information Block) or SIB

[0481] - RRC (Radio Resource Control)

[0482] - MAC (Medium Access Control) CE (Control Element)

[0483] In addition, L1 signaling may be signaling corresponding to at least one or a combination of one or more signaling methods using the physical layer channel or signaling below.

[0484] - PDCCH (Physical Downlink Control Channel)

[0485] - DCI (Downlink Control Information)

[0486] - UE-specific DCI

[0487] - Group common DCI

[0488] - Common DCI

[0489] - Scheduling DCI (e.g. DCI used for scheduling downlink or uplink data)

[0490] - Non-scheduled DCI (e.g. DCI not intended for scheduling downlink or uplink data)

[0491] - PUCCH (Physical Uplink Control Channel)

[0492] - UCI (Uplink Control Information)

[0493] 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.

[0494] The term slot used in the present disclosure below is a general term that may refer to a specific time unit corresponding to a TTI (Transmit Time Interval), and may specifically mean a slot used in a 5G NR system, or a slot or subframe used in a 4G LTE system.

[0495] 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.

[0496] As one embodiment of the present disclosure, a method for calculating the difference in path loss between a terminal and a base station is described. This embodiment can be operated in combination with other embodiments.

[0497] FIG. 18 is a diagram illustrating an example of the operation of a base station and a terminal operating in multiple TRPs, including a TRP that supports only an uplink reception function according to one embodiment of the present disclosure.

[0498] Referring to FIG. 18, a terminal (18-10) can be connected to and operate with a base station that operates with multiple TRPs as described above. The terminal (18-10) can assume that each of the plurality of TRPs supports both uplink reception and downlink transmission. In addition to the conventional TRP (18-00) that can perform both uplink reception and downlink transmission, the base station can also operate a TRP (18-05) that supports only uplink reception, for the purpose of improving uplink coverage from the perspective of the terminal (18-10) or for the purpose of energy saving benefits that can be obtained by saving downlink transmission power at the base station. This TRP (18-05) that supports only uplink reception can be named a UL-only TRP. The terminal (18-10) can assume that downlink transmission is not performed from the UL-only TRP. As an assumption for such UL-only TRP, the base station and terminal (18-10) can consider at least one of the following combinations.

[0499] - UL-only TRP (18-05) can operate as UL-only TRP only for specific terminals (for example, terminal (18-10). That is, UL-only TRP (18-05) actually has both uplink reception and downlink transmission functions, but for specific terminals, it can support only uplink reception function under specific conditions (for example, by notifying the terminal that it is connected to UL-only TRP through a combination of at least one of specific upper layer signaling, MAC-CE, and L1 signaling). That is, it can support downlink transmission for other terminals. This UL-only TRP can expand uplink coverage by additionally operating only reception function of TRP already installed or newly installed near the location when specific terminals exist at the boundary of any cell coverage.

[0500] - UL-only TRP (18-05) does not support downlink transmission functions for all terminals, and can only support uplink reception functions. In other words, UL-only TRP (18-05) is a TRP with relatively low production and installation costs, and in addition to existing TRPs, it can additionally receive uplink transmissions from terminals, thereby obtaining reception diversity from the base station's perspective.

[0501] The terminal (18-10) can receive a path loss measurement reference signal from a TRP (18-00) capable of uplink and downlink operations, but since downlink transmission is not performed from the UL-only TRP (18-05), there may be a problem that the path loss between the UL-only TRP (18-05) and the terminal (18-10) cannot be known when the terminal (18-10) performs uplink transmission toward the UL-only TRP (18-05). To solve this situation, the base station and the terminal (18-10) may consider a combination of at least one of the following methods to obtain path loss information between the UL-only TRP (18-05) and the terminal (18-10).

[0502] [Method 2-1]

[0503] FIG. 19 is a diagram illustrating a method for calculating and updating a path loss difference value according to one embodiment of the present disclosure.

[0504] Referring to FIG. 19, a terminal (19-00) can be connected to and operate a base station that is configured with a TRP capable of uplink and downlink operations (e.g., TRP1 (19-05)) and a UL-only TRP capable of only uplink reception (e.g., TRP2 (19-10)). The terminal (19-00) and the base station can go through a series of processes of exchanging signals between the terminal (19-00) and the base station to obtain information on the amount of path loss between TRP2 (19-10) and the terminal (19-00).

[0505] [Process 2-1] Uplink transmission of terminal (19-00)

[0506] The terminal (19-00) can transmit an uplink signal to TRP1 (19-05) and TRP2 (19-10) (19-15). If the terminal (19-00) operates in FR1, the terminal (1900) can transmit an uplink signal to TRP1 (19-05) and TRP2 (19-10) with only a single uplink transmission, and if the terminal (19-00) operates in FR2, the terminal (19-00) can perform individual uplink transmissions by applying different transmission beams to TRP1 (19-05) and TRP2 (19-10). If the terminal (19-00) operates in FR2, when the terminal (19-00) determines the transmission power of individual uplink signals transmitted to TRP1 (19-05) and TRP2 (19-10), the terminal (19-00) may apply the same transmission power parameters (19-20). That is, when the terminal (19-00) determines the transmission power of two uplink signals, the terminal (19-00) may consider the same transmission power parameters (e.g., p0, alpha, closed loop index, and / or path loss between TRP1 (19-05) and the terminal (19-00). Accordingly, when the terminal (19-00) transmits an uplink signal to TRP2 (19-10), the terminal (19-00) may apply the path loss between TRP1 (19-05) and the terminal (19-00) to determine the transmission power of the uplink signal.

[0507] [Process 2-2] Calculating the difference in path loss at the base station

[0508] Afterwards, TRP1 (19-05) and TRP2 (19-10) can receive the uplink transmission of the terminal (19-00) and calculate the reception power P1 (19-30) and P2 (19-25) at each TRP. TRP2 (19-10) can transmit P2 to TRP1 (19-05) (19-35). TRP1 (19-05), which receives P2 from TRP2 (19-10), can calculate the difference between P1 and P2, d_P (19-40). When calculating d_P in TRP1 (19-05), (1940) TRP1 (19-05) can consider the receive beam gain in TRP1 (19-05), the receive beam gain in TRP2 (19-10), and the MPE (Maximum Permissible Exposure) value that can determine the transmit power reduction amount for each transmit beam and each transmit beam gain considered when the terminal transmits to TRP1 (19-05) and TRP2 (19-10) in case of FR2.

[0509] [Process 2-3] Transmitting the difference in path loss to the terminal (19-00)

[0510] The base station can calculate d_P, which is the difference between the path loss between TRP1 (19-05) and the terminal (19-00) and the path loss between TRP2 (19-10) and the terminal (19-00), and then notify the terminal (19-00) of the calculated value (19-45). The terminal (19-00) can obtain the d_P value (19-50), and, in addition to the path loss that can be measured through the reference signal for path loss measurement that can be received from TRP1 (19-05), can determine the uplink transmission power for TRP2 (19-10) by applying the d_P value during uplink transmission for TRP2 (19-10).

[0511] Through the above [Process 2-1] to [Process 2-3], the base station can use the reception power information of the uplink signal of the terminal (19-00) to calculate d_P, which is the difference value between the path loss between TRP1 (19-05) and the terminal (19-00) and the path loss between TRP2 (19-10) and the terminal (19-00). In the above [Process 2-3], the base station can process (for example, take the arithmetic mean) one or more d_P values ​​calculated by repeating [Process 2-1] and [Process 2-2] one or more times and transmit them to the terminal (19-00).

[0512] Meanwhile, if the terminal (19-00) is not a device fixed to a specific location such as a Customer Premises Equipment (CPE), but is a mobile device such as a smartphone, smartwatch, or tablet, d_P may be a value that changes over time. Accordingly, the above [Process 2-1] to [Process 2-3] may be set or activated to be repeated periodically or semi-continuously for the terminal (19-00), or may be triggered aperiodically for the terminal (19-00). In order to check the changing d_P value and transmit it to the terminal (19-00), the following additional processes may be considered between the terminal (19-00) and the base station.

[0513] [Process 2-4] Uplink transmission of terminal (19-00) after acquiring d_P

[0514] After acquiring d_P from the base station, the terminal (19-00) can transmit an uplink signal to TRP1 (19-05) and TRP2 (19-10) (19-55). If the terminal (19-00) operates in FR1, the terminal (19-00) can transmit an uplink signal to TRP1 (19-05) and TRP2 (19-10) with only a single uplink transmission. If the terminal (19-00) operates in FR2, the terminal (19-00) can perform individual uplink transmissions by applying different transmission beams to TRP1 (19-05) and TRP2 (19-10). If the terminal (19-00) operates in FR2, when the terminal (19-00) determines the transmission power of individual uplink signals transmitted to TRP1 (19-05) and TRP2 (19-10), the terminal (19-00) may apply the same transmission power parameters (19-60). That is, when the terminal (19-00) determines the transmission power of the two uplink signals, the terminal (19-00) may consider the same p0, alpha, closed loop index, and path loss between TRP1 (19-05) and the terminal.

[0515] In addition, although the terminal (19-00) has obtained the d_P value through the above [Process 2-3], the terminal (19-00) may transmit an uplink signal without applying d_P when determining the uplink transmission power to TRP2 (19-10) so that the base station can calculate the difference value between the path loss between TRP1 (19-05) and the terminal (19-00) and the path loss between TRP2 (19-10) and the terminal (19-00) by applying the same transmission power parameter to the two TRPs (19-05, 19-10) (1960). Accordingly, even when the terminal (19-00) transmits an uplink signal to TRP2 (19-10), the terminal (19-00) may apply only the path loss between TRP1 (19-05) and the terminal (19-00) to determine the transmission power of the uplink signal.

[0516] [Process 2-5] Calculating the difference in path loss at the base station

[0517] TRP1 (19-05) and TRP2 (19-10) can receive the uplink transmission of the terminal (19-00) in the above [Process 2-4], respectively, and calculate the reception power at each TRP, P1' (19-70) and P2' (19-65). TRP2 (19-10) can transmit P2' to TRP1 (19-05) (19-75). TRP1 (19-05), which receives P2' from TRP2 (19-10), can calculate the difference between P1' and P2', d_P' (19-80). When calculating d_P' in TRP1 (19-05), (19-80) TRP1 (19-05) can consider the receive beam gain in TRP1 (19-05), the receive beam gain in TRP2 (19-10), and the MPE (Maximum Permissible Exposure) value that can determine the transmit power reduction amount for each transmit beam and each transmit beam gain considered when the terminal transmits to TRP1 (19-05) and TRP2 (19-10) in case of FR2.

[0518] [Process 2-6] Transmitting the difference in path loss to the terminal

[0519] The base station can calculate d_P', which is the difference between the path loss between TRP1 (19-05) and the terminal (19-00) and the path loss between TRP2 (19-10) and the terminal (19-00), and then notify the terminal (19-00) of the calculated value (19-85). The terminal (19-00) can obtain the updated d_P' value compared to the previously obtained d_P value (19-90), and thereafter, when transmitting uplink for TRP2 (19-10), in addition to the path loss that can be measured through the reference signal for measuring the path loss that can be received from TRP1 (19-05), can determine the uplink transmission power for TRP2 (19-10) by applying the d_P' value.

[0520] Thereafter, the terminal (19-00) and the base station may repeat [Step 2-4] to [Step 2-6] to calculate and share an updated value for the d_P value. In [Step 2-6], the base station may process (for example, take an arithmetic mean) one or more d_P' values ​​calculated by repeating [Step 2-4] and [Step 2-5] one or more times and transmit them to the terminal (19-00).

[0521] If the terminal (19-00) performs the uplink transmission shown in the above [Process 2-1] and [Process 2-4], the terminal (19-00) can set one or more SRS resources in the SRS resource set in which the upper layer signaling resourceType is set to periodic, semi-persistent, or aperiodic, and perform the above [Process 2-1] and [Process 2-4] based on SRS transmission, and all of the one or more SRS resources can have the same transmission power parameter.

[0522] If the terminal (19-00) operates in FR1, the terminal (19-00) can apply the same transmission power parameter (for example, at least one of p0, alpha, closed loop index, or path loss) to TRP1 (19-05) and TRP2 (19-10) based on one SRS resource in the SRS resource set, and even if it is an uplink transmission for TRP2 (19-10), the difference value of the path loss may not be applied when determining the transmission power as described above. If the terminal (19-00) operates in FR2, the terminal (19-00) can apply the same transmission power parameter (for example, p0, alpha, closed loop index, and path loss) to TRP1 (19-05) and TRP2 (19-10) based on one or more SRS resources in the SRS resource set, and can apply different transmission beams to each SRS resource. Similarly to the above, the terminal (19-00) may not apply the difference value of the path loss amount when determining the transmission power of the uplink transmission for TRP2 (19-10).

[0523] The terminal (19-00) can also perform the uplink transmission shown in [Process 2-1] and [Process 2-4] through an uplink channel and signal other than SRS (for example, at least one of PUCCH, PUSCH, or PRACH).

[0524] When the terminal (19-00) performs uplink transmission as shown in [Process 2-1] and [Process 2-4], it is necessary to apply the same transmission power parameter to the uplink channel or signal transmitted to TRP1 (19-05) and TRP2 (19-10) within each process, but it may be possible to use different transmission power parameters between processes (for example, the transmission power parameter used in [Process 2-1] and the transmission power parameter used in [Process 2-4]).

[0525] For example, if the terminal (19-00) determines the uplink transmission power using the first p0, the first alpha, the first closed circuit index, and / or the first path loss in [Process 2-1] and transmits the uplink transmission power to TRP1 (19-05) and TRP2 (19-10), then the terminal (19-00) may be able to determine the uplink transmission power using the second p0, the second alpha, the second closed circuit index, and / or the second path loss in [Process 2-4] and transmit the uplink transmission power to TRP1 (19-05) and TRP2 (19-10). In this case, the first p0 and the second p0 may be the same or different, and a similar relationship may be established for other transmission power parameters.

[0526] In the case of the above [Method 2-1], the terminal (19-00) can receive the d_P value from the base station through the above [Process 2-3] and [Process 2-6]. In the case of the above [Method 2-1], since the terminal (19-00) receives the d_P value from the base station, when the same quantization bit amount is considered, an inaccurate value may be received compared to receiving the d_P'' value that can be considered in the following [Method 2-2]. However, as described above, since there is no restriction that the same transmission power parameter must be used between each transmission time point as in the above [Process 2-1] and [Process 2-4], the base station can be flexible in operating such uplink transmission.

[0527] [Method 2-2]

[0528] FIG. 20 is a diagram illustrating another method for calculating and updating a path loss difference value according to one embodiment of the present disclosure.

[0529] Referring to FIG. 20, a terminal (20-00) may be connected to and operate a base station that is configured with a TRP capable of uplink and downlink operations (e.g., TRP1 (20-05)) and a UL-only TRP capable of only uplink reception (e.g., TRP2 (20-10)). The terminal (20-00) and the base station may go through a series of processes of exchanging signals between the terminal (20-00) and the base station to obtain information on the amount of path loss between TRP2 (20-10) and the terminal (20-00).

[0530] [Process 3-1] Uplink transmission of terminal (20-00)

[0531] The terminal (20-00) can transmit an uplink signal to TRP1 (20-05) and TRP2 (20-10) (20-15). If the terminal (20-00) operates in FR1, the terminal (20-00) can transmit an uplink signal to TRP1 (20-05) and TRP2 (20-10) with only a single uplink transmission. If the terminal (20-00) operates in FR2, the terminal (20-00) can perform individual uplink transmissions by applying different transmission beams to TRP1 (20-05) and TRP2 (20-10).

[0532] If the terminal (20-00) operates in FR2, when the terminal (20-00) determines the transmission power of individual uplink signals transmitted to TRP1 (20-05) and TRP2 (20-10), the terminal (20-00) may apply the same transmission power parameters (2020). That is, when the terminal (20-00) determines the transmission power of two uplink signals, the terminal (20-00) may consider the same p0, alpha, closed loop index, and / or path loss between TRP1 (20-05) and the terminal (20-00). The terminal (20-00) may apply the path loss between TRP1 (20-05) and the terminal (20-00) to determine the transmission power of the uplink signal transmitted to TRP2 (20-10).

[0533] [Process 3-2] Calculating the difference in path loss at the base station

[0534] Afterwards, TRP1 (20-05) and TRP2 (20-10) can receive the uplink transmission of the terminal (20-00) and calculate the reception power P1 (20-30) and P2 (20-25) at each TRP. TRP2 (20-10) can transmit P2 to TRP1 (20-05) (20-35). TRP1 (20-05), which receives P2 from TRP2 (20-10), can calculate the difference between P1 and P2, d_P (20-40). When calculating d_P in TRP1 (20-05), (2040) TRP1 (20-05) may consider the receive beam gain in TRP1 (20-05), the receive beam gain in TRP2 (20-10), and in case of FR2, the terminal (20-00) may consider each transmit beam gain and / or the MPE (Maximum Permissible Exposure) value that can determine the amount of transmit power reduction for each transmit beam when transmitting to TRP1 (20-05) and TRP2 (20-10).

[0535] [Process 3-3] Transmitting the difference in path loss to the terminal (20-00)

[0536] The base station can calculate d_P, which is the difference between the path loss between TRP1 (20-05) and the terminal (20-00) and the path loss between TRP2 (20-10) and the terminal (20-00), and then notify the terminal (20-00) of the calculated value (20-45). The terminal (20-00) can obtain the d_P value (20-50), and thereafter, when performing uplink transmission for TRP2 (20-10), in addition to the path loss that can be measured through the reference signal for path loss measurement that can be received from TRP1 (20-05), the base station can determine the uplink transmission power for TRP2 (20-10) by applying the obtained d_P value.

[0537] Through the above [Process 3-1] to [Process 3-3], the base station can use the reception power information of the uplink signal of the terminal (20-00) to calculate d_P, which is the difference value between the path loss between TRP1 (20-05) and the terminal (20-00) and the path loss between TRP2 (20-10) and the terminal (20-00). In the above [Process 3-3], the base station can process (for example, take the arithmetic mean) one or more d_P values ​​calculated by repeating [Process 3-1] and [Process 3-2] one or more times and transmit them to the terminal (20-00). In addition, in the above [process 3-3], the base station may initially perform the notification of the d_P value to the terminal (20-00) once at the base station, and when the terminal (20-00) and the base station repeat [process 3-1] and [process 3-2] thereafter, the base station may optionally perform the above [process 3-3].

[0538] Meanwhile, if the terminal (20-00) is not a device fixed to a specific location such as a Customer Premises Equipment (CPE), for example, if the terminal is a mobile device such as a smartphone, smartwatch, or tablet, d_P may be a value that changes over time. Accordingly, the above [Process 3-1] to [Process 3-3] may be set or activated to be repeated periodically or semi-continuously for the terminal (20-00), or may be triggered aperiodically for the terminal (20-00). If the above [Process 2-4] to [Process 2-6] were methods in which the terminal (20-00) and the base station updated the d_P value and shared it with each other, the following [Process 3-4] to [Process 3-6] may be methods in which the terminal (20-00) and the base station consider the d_P value acquired through the above [Process 3-1] to [Process 3-3] as an initial value, calculate the amount of change therein, and share it with each other. In order to check the change in the d_P value and transmit it to the terminal (20-00), the following additional processes may be considered between the terminal (20-00) and the base station.

[0539] [Process 3-4] Uplink transmission of terminal (20-00) after acquiring d_P

[0540] After acquiring d_P from the base station, the terminal (20-00) can transmit an uplink signal to TRP2 (20-10) (20-55). The terminal (20-00) can use p0, alpla, and / or the closed circuit index among the transmission power parameters used in the above [Process 3-1], and in the case of path loss, the d_P value acquired in the above [Process 3-3] can be applied to the path loss between TRP1 (20-05) and the terminal (20-00) (20-60). If the terminal (20-00) operates in FR2, the terminal (20-00) can use the same or different transmission beams used in the above [Process 3-1] and the corresponding [Process 3-4]. If the terminal (20-00) uses the same transmission beam in the above [process 3-1] and the corresponding [process 3-4], the base station does not have to compensate for the difference in transmission beam gain value due to the change in transmission beam in the terminal (20-00) when calculating the change in d_P in the subsequent process. However, if this is not the case (i.e., if the terminal (20-00) uses different transmission beams in the above [process 3-1] and the corresponding [process 3-4]), the base station can compensate for the difference in each transmission beam gain value in the subsequent process to increase the accuracy when calculating the change in d_P value.

[0541] [Process 3-5] Calculating the difference in path loss at the base station

[0542] Afterwards, TRP2 (20-10) can receive the uplink transmission of the terminal (20-00) in the above [Process 3-4] and calculate the reception power P2'' (20-65). TRP2 (20-10) can compare the value obtained by subtracting the d_P value from the P2 calculated in the above [Process 3-2] (for example, P2 - d_P) with the P2'' value. The P2 is a reception power value calculated based on a transmission power parameter that does not consider the difference value of the path loss amount, and the P2'' is a reception power value calculated by additionally applying the difference value of the path loss amount to the same transmission power parameter as when calculating the P2. Therefore, comparing the value obtained by subtracting the d_P value from P2 and the P2'' may be the same as estimating the amount of change in the d_P value.

[0543] Through this, TRP2 (20-10) can calculate the d_P'' value, which is the change in the d_P value (20-70). When calculating d_P'' in TRP2 (20-10) (20-70), TRP2 (20-10) can consider the reception beam gain in TRP2 (20-10), and the MPE (Maximum Permissible Exposure) value that can determine the transmission power reduction amount for each transmission beam and each transmission beam gain considered by the terminal when transmitting to TRP2 (20-10) in case of FR2. TRP2 (20-10) can update the previously calculated d_P value by considering the calculated d_P'' (20-71) (for example, d_P = d_P - d_P''). Afterwards, TRP2 (20-10) can transfer the above d_P'' value to TRP1 (20-05) (20-75).

[0544] [Process 3-6] Transmitting the difference in path loss to the terminal (20-00)

[0545] The base station can calculate the change in d_P, which is the difference in path loss between TRP1 (20-05) and the terminal (20-00) and the path loss between TRP2 (20-10) and the terminal (20-00), and then notify the terminal (20-00) of the calculated value (20-80). The terminal (20-00) can obtain an updated d_P value by applying the change in d_P to the previously obtained d_P value (20-85). Thereafter, when performing uplink transmission for TRP2 (20-10), the terminal (20-00) can determine the uplink transmission power for TRP2 (20-10) by applying the d_P value, which is the difference in path loss, and the change in d_P'', in addition to the path loss that can be measured through the reference signal for path loss measurement that can be received from TRP1 (20-05).

[0546] The terminal (20-00) and the base station may repeat [Step 3-4] to [Step 3-6] to calculate and share an updated value for the d_P value. In the [Step 3-6], the base station may process (for example, take the arithmetic mean) one or more d_P'' values ​​calculated by repeating [Step 3-4] and [Step 3-5] one or more times and transmit the processed values ​​to the terminal (20-00). In addition, the TRP2 (20-10) may use the processed (for example, take the arithmetic mean) one or more d_P'' values ​​calculated by repeating [Step 3-4] and [Step 3-5] one or more times to update the d_P value in the [Step 3-5].

[0547] When the terminal (20-00) performs uplink transmission as shown in the above [process 3-1], it can perform SRS transmission based on one or more SRS resources within an SRS resource set in which the resourceType, which is an upper layer signaling, is set to periodic, semi-persistent, or aperiodic, and all of these one or more SRS resources can have the same transmission power parameter.

[0548] If the terminal (20-00) operates in FR1, the terminal (20-00) can apply the same transmission power parameters (e.g., p0, alpha, closed loop index, and / or path loss) to TRP1 (20-05) and TRP2 (20-10) based on one SRS resource within the SRS resource set, and even if it is an uplink transmission for TRP2 (20-10), the difference in path loss may not be applied when determining the transmission power as described above. If the terminal (20-00) operates in FR2, the terminal (20-00) can apply the same transmission power parameters (e.g., p0, alpha, closed loop index, and / or path loss) to TRP1 (20-05) and TRP2 (20-10) based on one or more SRS resources within the SRS resource set, and can apply different transmission beams to each SRS resource. Similarly to the above, even if the terminal (20-00) is transmitting uplink to TRP2 (20-10), the difference value of the path loss may not be applied when determining the transmission power as described above.

[0549] When the terminal (20-00) performs uplink transmission as shown in the above [process 3-4], it can perform SRS transmission based on one or more SRS resources within an SRS resource set in which the upper layer signaling resourceType is set to periodic, semi-persistent, or aperiodic, and all of these one or more SRS resources can have the same transmission power parameter.

[0550] If the terminal (20-00) performs both the uplink transmission in [Process 3-1] and the uplink transmission in [Process 3-4] based on an SRS resource within an SRS resource set in which the resourceType is set to periodic or semi-persistent, the terminal (20-00) can assume that the period of the uplink transmission for [Process 3-1] is longer than or equal to the period of the uplink transmission for [Process 3-4].

[0551] For example, if the period of uplink transmission for the above [process 3-1] is 10 slots and the period of uplink transmission for the above [process 3-4] is 2 slots, the terminal (20-00) does not need to consider the constraint that the transmission power parameter must be the same between each transmission time point of the uplink transmission for the above [process 3-1], and as described above, when transmissions for TRP1 (20-05) and TRP2 (20-10) are performed individually within each transmission time point of the uplink transmission for the above [process 3-1], the transmission power parameter may be considered to be the same during transmission for the two TRPs.

[0552] In addition, the terminal (20-00) may use the transmission power parameters used in the transmission cycle of the uplink transmission for the most recent [process 3-1] performed prior to the uplink transmission for the uplink transmission for the [process 3-4]. For example, if the terminal (20-00) performed the uplink transmission for the [process 3-1] in slot n and used the first transmission power parameter set at this time, the terminal (20-00) may use the first transmission power parameter set for the uplink transmission for the [process 3-4] from slot n to before slot n+10, which is the next cycle, and as described above, the difference value of the above-described path loss may also be applied during the uplink transmission for the [process 3-4]. This is because in the above [Process 3-4], when calculating d_P'' in TRP2 (20-10), the P2 value, which is the received power calculated through the previous uplink transmission, is taken into consideration, so there must be a constraint that the transmission power parameter must be the same for the two uplink transmissions, so that a more accurate d_P'' value can be calculated.

[0553] The terminal (20-00) can also perform the uplink transmission shown in [Process 3-1] and [Process 3-4] through uplink channels and signals other than SRS (e.g., PUCCH, PUSCH, and / or PRACH).

[0554] In the case of the above [Method 2-2], the terminal (20-00) can receive the d_P value from the base station at least once initially through the above [Process 3-3], and can be notified of the d_P'' value from the base station through the above [Process 3-6]. In the case of the above [Method 2-2], although the terminal (20-00) may need to be configured by the base station for different uplink transmissions for the above [Process 3-1] and [Process 3-4], signaling overhead may be added for this, but when the same quantization bit amount is considered, the terminal (20-00) may have the advantage of being able to receive a more accurate value for the difference in path loss amount by receiving the d_P'' value compared to receiving the d_P value from the base station.

[0555] Through the above-described [Method 2-1] and [Method 2-2], a terminal (e.g., terminal (19-00 or 20-00)) can use the modified transmission power calculation formula as follows when determining uplink transmission power for UL-only TRP.

[0556] For example, when determining the PUCCH transmission power for a UL-only TRP (e.g., TRP2(19-10 or 20-10)) that supports only uplink reception operation, the terminal may modify and use the conventional PUCCH transmission power-related mathematical expression as in [Mathematical Expression 2] below. In [Mathematical Expression 2] below, can be regarded as the d_P value, which is the difference in path loss, may mean that the difference in the corresponding path loss corresponds to one or more path loss measurement reference signals. The terminal If it corresponds to one path loss measurement reference signal, It can also be considered as. In addition, if the terminal reflects the difference value of the path loss amount in the form of adding to the path loss amount as in [Mathematical Formula 2] below in the PUCCH transmission power calculation formula, the difference value of the path loss amount may be less than or equal to 0. Similarly, the difference value of the path loss amount may be reflected in the form of subtraction from the path loss amount in the PUCCH transmission power calculation formula as in [Mathematical Formula 3] below, and in this case, the difference value of the path loss amount may be greater than or equal to 0.

[0557] [Equation 2]

[0558]

[0559] [Equation 3]

[0560]

[0561] As another example, when determining PUSCH transmission power for UL-only TRP that supports only uplink reception operation, the terminal may modify and use the conventional PUSCH transmission power related mathematical equation as in [Mathematical Equation 4] or [Mathematical Equation 5] below. In [Mathematical Equation 4] or [Mathematical Equation 5] below, can be regarded as the d_P value, which is the difference in path loss, may mean that the difference in the corresponding path loss corresponds to one or more path loss measurement reference signals. The terminal If it corresponds to one path loss measurement reference signal, It can be considered as [Mathematical Formula 4] or [Mathematical Formula 5] below, which is the difference in path loss. It can be distinguished depending on whether the value is directly applied to the path loss amount. In addition, if the terminal reflects the difference value of the path loss amount in the form of adding the path loss amount to the PUSCH transmission power calculation formula as in [Mathematical Formula 4] or [Mathematical Formula 5] below, the difference value of the path loss amount may be less than or equal to 0. Similarly, the difference value of the path loss amount may be reflected in the form of subtraction from the path loss amount in the PUSCH transmission power calculation formula as in [Mathematical Formula 6] and [Mathematical Formula 7] below, and in this case, the difference value of the path loss amount may be greater than or equal to 0.

[0562] [Equation 4]

[0563]

[0564] [Equation 5]

[0565]

[0566] [Equation 6]

[0567]

[0568] [Equation 7]

[0569]

[0570] As another example, when determining PUSCH transmission power for UL-only TRP that supports only uplink reception operation, the terminal may modify and use the conventional PUSCH transmission power related mathematical equation as in [Mathematical Equation 8] or [Mathematical Equation 9] below. In [Mathematical Equation 8] or [Mathematical Equation 9] below, can be regarded as the d_P value, which is the difference in path loss, may mean that the difference in the corresponding path loss corresponds to one or more path loss measurement reference signals. The terminal If it corresponds to one path loss measurement reference signal, It can be considered as [Mathematical Formula 8] or [Mathematical Formula 9] below, which is the difference in path loss. It can be distinguished depending on whether the value is directly applied to the path loss amount. In addition, if the terminal reflects the difference value of the path loss amount in the form of adding to the path loss amount as in [Mathematical Formula 8] or [Mathematical Formula 9] below in the SRS transmission power calculation formula, the difference value of the path loss amount may be less than or equal to 0. Similarly, the difference value of the path loss amount may be reflected in the form of subtraction from the path loss amount in the SRS transmission power calculation formula as in [Mathematical Formula 10] and [Mathematical Formula 11] below, and in this case, the difference value of the path loss amount may be greater than or equal to 0.

[0571] [Equation 8]

[0572]

[0573] [Equation 9]

[0574]

[0575] [Equation 10]

[0576]

[0577] [Equation 11]

[0578]

[0579] The terminal considers the uplink bandwidth part b activated through [Mathematical Expression 12] and / or [Mathematical Expression 13], the carrier frequency f, cell c, and the downlink path loss measurement reference signal within cell c, and the transmission power of the PRACH in the i-th PRACH transmission occasion. can be calculated.

[0580] [Equation 12]

[0581]

[0582] [Equation 13]

[0583]

[0584] - : The maximum transmission power available to the terminal in the i-th transmission unit can be determined by the power class of the terminal, parameters activated from the base station, and various parameters built into the terminal.

[0585] - : It may mean the target reception power of PRACH, which can be set with upper layer signaling PREAMBLE_RECEIVED_TARGET_POWER for activated uplink bandwidth part b, carrier frequency f, and cell c.

[0586] - : Among the downlink reference signals defined in the activated downlink bandwidth portion within cell c, based on those associated with the corresponding PRACH transmission, the activated uplink bandwidth portion b, carrier frequency f, may be a value indicating the path loss between the base station and the terminal within cell c, and the terminal may calculate the path loss value in dB by subtracting the upper layer filtered RSRP value from the transmission power (e.g., referenceSignalPower) of the downlink path loss measurement reference signal. If the activated downlink bandwidth portion is the initial downlink bandwidth portion and the multiplexing pattern between the SSB and the control resource set is 2 or 3, or the corresponding PRACH transmission is for a TRP having a different PCI from the serving cell, the terminal may calculate the path loss value can be calculated based on the SSB associated with the corresponding PRACH transmission.

[0587] - : This parameter may mean the difference between the path loss between the TRP and the terminal, which enables both uplink and downlink operations, and the path loss between the UL-only TRP and the terminal, when the terminal is connected to a base station supporting UL-only TRP. The parameter may have a value other than 0 or 0 if it has received specific upper layer signaling that may mean that the terminal is connected to a base station supporting UL-only TRP, and otherwise, the value may be regarded as 0. If the difference value of the path loss amount is included in the form of being added to the PRACH transmission power calculation formula as in [Mathematical Formula 12], the difference value of the path loss amount may be less than or equal to 0. If the difference value of the path loss amount is applied in the form of being subtracted from the path loss amount in the PRACH transmission power calculation formula as in [Mathematical Formula 13], the difference value of the path loss amount may be greater than or equal to 0.

[0588] If a PRACH transmission is initiated by the UE receiving a PDCCH order for triggering a contention-free random access procedure, and if the PRACH transmission is for a serving cell and the downlink path loss measurement reference signal is an SSB, which is a downlink reference signal in a QCL relationship with a DMRS in the PDCCH order, or if the PRACH transmission is for a TRP having a different PCI from the serving cell and the downlink path loss measurement reference signal is an indicated SSB, the UE may assume that the referenceSignalPower is determined by the higher layer signaling ss-PBCH-BlockPower. If the UE has been configured with a periodic CSI-RS as a path loss measurement reference signal, the UE may assume that the referenceSignalPower is determined by the higher layer signaling ss-PBCH-BlockPower and powerControlOffsetSS, where powerControlOffsetSS may mean an offset between the SSB transmission power and the CSI-RS transmission power. If the terminal does not set powerControlOffsetSS, the terminal may regard the offset as 0 dB. If the activated TCI state for the control resource set in which the PDCCH order is transmitted includes two reference signals, i.e., if the activated TCI state includes both qcl-Type1 and qcl-Type2, the terminal may consider the powerControlOffsetSS for the reference signal set in qcl-Type2 when calculating the referenceSignalPower.

[0589] The terminal may be notified by the base station of at least one combination of [Method 2-1] and [Method 2-2] through at least one combination of upper layer signaling, MAC-CE signaling, and L1 signaling, or may expect that at least one combination of [Method 2-1] and [Method 2-2] is fixedly defined in the standard. Additionally, if the terminal is notified by the base station of at least one combination of specific methods through at least one combination of upper layer signaling, MAC-CE signaling, and L1 signaling, it may mean that the terminal cannot support one or more other combinations of specific methods.

[0590] For example, the terminal may expect that [Method 2-1] or [Method 2-2] is fixedly defined in the standard for the method of obtaining and updating the difference in path loss amount. As another example, the terminal may be notified of [Method 2-1] from the base station through a combination of at least one of upper layer signaling, MAC-CE signaling, and L1 signaling, and in this case, the terminal may consider that the base station has notified that [Method 2-2] is not supported.

[0591] The terminal may report to the base station, based on the terminal capability, whether it can support at least one combination of [Method 2-1] and [Method 2-2]. If the terminal reports to the base station, based on the terminal capability, that it can support a combination of one or more specific methods, it may be regarded as reporting that the terminal cannot support one or more other combinations of methods. For example, the terminal may report to the base station, based on the terminal capability, whether it can support [Method 2-1] or [Method 2-2]. As another example, the terminal may report to the base station that it can support [Method 2-1], and this terminal capability report may mean that the terminal cannot support [Method 2-2].

[0592] As one embodiment of the present disclosure, a method for scheduling uplink transmissions for UL-only TRP is described by indicating a path loss difference value to a terminal. This embodiment can be operated in combination with other embodiments.

[0593] In the present disclosure, the difference value of the path loss amount may be named pathloss offset, PL offset, path loss amount offset, or path loss amount offset.

[0594] As described above, the terminal can set the difference value of the path loss amount from the base station as an upper layer signaling. Since the terminal cannot receive the path loss measurement reference signal from the UL-only TRP, the path loss amount between the terminal and the UL-only TRP cannot be directly measured. Therefore, the terminal can indirectly calculate the path loss amount from the UL-only TRP by applying the difference value of the path loss amount to the path loss amount calculated based on the path loss measurement reference signal received from the TRP capable of both uplink and downlink operations.

[0595] A terminal can receive an uplink scheduling from a base station, and can distinguish whether the uplink scheduling is a transmission for a UL-only TRP or a transmission for a TRP capable of both uplink and downlink operations based on information included in the uplink scheduling. In this case, the uplink scheduling may include information related to a difference value of path loss amounts. In this way, a method for a terminal to receive an uplink scheduling including information related to a difference value of path loss amounts from a base station may consider a combination of at least one of the following items.

[0596] [Method 3-1]

[0597] A terminal can receive one or more joint TCI states or UL TCI states from a base station through upper layer signaling, and at this time, as shown in [Table 15] below, the terminal can receive information on the difference value of path loss within one or more joint TCI states or UL TCI states.

[0598] [Table 15]

[0599]

[0600] In the above [Table 15], the terminal can receive pathlossOffset as upper layer signaling for the difference value of the path loss amount, and the value can be an integer from Xs to Xe.

[0601] - In one embodiment, Xs and Xe can be 0 and natural numbers (for example, 0 and 30, respectively), and the value of pathlossOffset can be in units of 1 dB. The reason why negative values ​​of pathlossOffset are not considered is that when a terminal considers multiple UL-only TRPs, it is assumed that the distance between the terminal and the UL-only TRP is closer than the distance between the TRPs that can operate in uplink and downlink, and thus a higher reception signal quality can be assumed when receiving from the UL-only TRP during uplink transmission of the terminal.

[0602] - In one embodiment, Xs and Xe can be integers including positive and negative numbers (for example, -10 and 50, respectively), and the value of pathlossOffset can be in units of 1 dB. The reason why the value of pathlossOffset can be considered up to a negative number is that when the terminal considers multiple UL-only TRPs, the distance between the terminal and some UL-only TRPs is considered to be longer than the distance between the terminal and the TRPs that can operate in uplink and downlink, so that even if the terminal receives a low reception signal quality in some UL-only TRPs during uplink transmission, if the same signal is received in multiple UL-only TRPs, a diversity effect can be obtained.

[0603] - In one embodiment, Xs and Xe may be 2 and 32, respectively, and the value of pathlossOffset may be in units of 2 dB. The range and unit of such values ​​may be borrowed from the range and unit of the differential RSRP (reference signal received power) value that the terminal can report to the base station. When the terminal reports L1-RSRP (layer 1 RSRP), which is one of the channel state information that can indicate the strength of the received signal, the largest value among the L1-RSRP corresponding to the number of values ​​set by the upper layer signaling to the terminal may be quantized into 7 bits and reported in the range from -140 dBm to 44 dBm in units of 1 dB, and one or more L1-RSRP values ​​smaller than that may be reported by calculating differential RSRP that can be expressed as a difference value with respect to the largest value, and at this time, the differential RSRP value may be quantized into 4 bits and the range of the value may be reported in the range from 2 dB to 32 dB in units of 2 dB. Path loss is calculated by calculating the difference between the RSRP value calculated by the terminal and the transmission power value of the reference signal that can be received from the base station for calculating the path loss. If the differential value of the path loss is calculated, the range and unit of the differential RSRP value can be reused.

[0604] A terminal can define ULonlyNode as a condition under which the pathlossOffset can be set by the base station in the joint TCI state or the UL TCI state. The condition ULonlyNode can mean that the terminal operates in a cell containing a UL-only TRP, which can mean when a specific upper layer signaling is set. That is, when a specific upper layer signaling is set, the terminal can optionally receive the pathlossOffset. The name of this condition ULonlyNode is only an example and can be expressed by other names. If the terminal does not receive the pathlossOffset set in the joint TCI state or the UL TCI state, the terminal can regard the difference value of the path loss amount as 0.

[0605] The terminal may be instructed by the base station to use the TCI state field in the DCI for one or more of the joint TCI states or UL TCI states set as shown in [Table 15]. If the terminal receives the joint TCI state or UL TCI state with the pathlossOffset set and receives scheduling from the base station to perform uplink transmission by applying the joint TCI state or UL TCI state, the terminal may regard the uplink transmission as transmission for UL-only TRP.

[0606] When calculating the transmission power for the above uplink transmission, the terminal may calculate the path loss between the terminal and the UL-only TRP by applying the difference value of the path loss indicated by the pathlossOffset value set in the joint TCI state or the UL TCI state in addition to the path loss measured through the path loss measurement reference signal (for example, pathlossReferenceRS-Id-r17 in the above [Table 15]) set in the joint TCI state or the UL TCI state. It may be assumed that the terminal has received the path loss measurement reference signal (for example, pathlossReferenceRS-Id-r17 in the above [Table 15]) from a TRP capable of operating in both uplink and downlink.

[0607] When using the above [Method 3-1], the terminal can receive different path loss difference values ​​from the base station for each TCI state, so even if the same path loss reference signal is set within each TCI state using different TCI states, the terminal can calculate different path losses using the different path loss difference values ​​set within each TCI state. Through the above method, the terminal can easily use multiple path loss difference values ​​if one or more UL-only TRPs are installed in the network to which the terminal is connected. However, when the terminal uses the above method, the number of path loss difference values ​​that the terminal and the base station must manage increases, and the update thereof must be supported for each TCI state, which may consume a lot of signaling overhead.

[0608] The terminal can use the above [Method 3-1] when transmitting at least one channel / signal among PUSCH, PUCCH, SRS, and PRACH. If the terminal applies the above [Method 3-1] to the terminal's PUSCH, PUCCH, and SRS transmission, the terminal can calculate the transmission power by applying the difference value of the path loss amount included in the TCI state indicated by the base station when transmitting the corresponding uplink channel / signal. If the terminal applies the above [Method 3-1] to PRACH transmission, the terminal can apply it to PRACH transmission that can be triggered by DCI format 1_0, and the base station and the terminal can define a new field in the DCI format 1_0, and the terminal can receive one TCI state from among a maximum of two joint TCI states (if the terminal has received the upper layer signaling unifiedTCI-StateType set to joint) or a maximum of two UL TCI states (if the terminal has received the upper layer signaling unifiedTCI-StateType set to separate) currently indicated and applied by the base station to the terminal, and can use the difference value of the path loss amount set in the corresponding TCI state to determine the transmission power of the PRACH. At this time, the size of the new field in DCI format 1_0 can be 1 bit, and if the terminal is instructed to be 0 through the new field, the terminal can determine the transmission power of the PRACH by applying the difference value of the path loss amount set in the first TCI state instructed and applied to the terminal, and if the terminal is instructed to be 1 through the new field, the terminal can determine the transmission power of the PRACH by applying the difference value of the path loss amount set in the second TCI state instructed and applied to the terminal.If the difference value of path loss is not set within the first and / or second TCI states, the terminal may not apply the difference value of path loss when determining the transmission power of the PRACH. In other words, this may have the same effect as the terminal considering the difference value of path loss as 0 dB and applying it when determining the transmission power of the PRACH.

[0609] The terminal can set the difference value of the path loss amount through upper layer signaling in the joint TCI state or UL TCI state as shown in [Table 15] above (an example of setting the difference value of the path loss amount through pathlossOffset is provided in [Table 15] above, and the parameter name pathlossOffset is only an example, and other parameter names that can indicate the difference value of the path loss amount may also be possible, and regardless of the parameter name used, the meaning expressed by the parameter can be the difference value of the path loss amount) and update it through MAC-CE. The terminal can consider at least one combination of the following items as information that can be included in the MAC-CE signaling.

[0610] - Serving cell ID field (e.g. 5 bits)

[0611] - Downlink bandwidth part ID field (e.g. 2 bits)

[0612] - Uplink bandwidth part ID field (e.g. 2 bits)

[0613] - Path loss measurement reference signal ID field (e.g. 6 bits)

[0614] - Path loss measurement reference signal group field (e.g. 2 bits)

[0615] - Activated path loss measurement reference signal ID field (e.g. 2 bits)

[0616] - Path loss difference value (d_P) field (e.g. 5 to 8 bits)

[0617] - Variation of difference value of path loss amount (d_P'') field (e.g. 5 to 8 bits)

[0618] - A field indicating the number of joint TCI states or UL TCI states (if the number of joint TCI states or UL TCI states that can be indicated through the corresponding MAC-CE is at most N, the number of joint TCI states or UL TCI states can have ceil(log2(N))-bits, where ceil(.) can mean a rounding function and log2(.) can mean a logarithmic function with base 2. If the corresponding MAC-CE always indicates 1 joint TCI state or 1 UL TCI state, the corresponding field may not exist.)

[0619] - Joint TCI state or UL TCI state field (7 or 6 bits respectively)

[0620] As an example of a combination of MAC-CE signaling configuration information, a terminal may expect that the MAC-CE signaling includes at least a Serving cell ID field, a downlink bandwidth part ID field, an uplink bandwidth part ID field, a path loss difference value (d_P) field, one or more joint TCI states, or one or more UL TCI state fields.

[0621] - The terminal may receive the MAC-CE signaling and update the difference value of the path loss amount set in one or more joint TCI states that can be indicated through the MAC-CE, which are set in the downlink bandwidth portion that can be indicated through the MAC-CE, to the difference value of the path loss amount that can be indicated through the MAC-CE. That is, the terminal may update the difference value of the path loss amount that can be indicated through the MAC-CE equally for the difference values ​​of the path loss amounts that can be the same or different, which are respectively set in one or more joint TCI states that can be indicated through the MAC-CE.

[0622] - Alternatively, the terminal may receive the MAC-CE signaling and update the difference value of the path loss amount set in one or more UL TCI states that can be indicated through the MAC-CE, which are set in the uplink bandwidth portion that can be indicated through the MAC-CE, to the difference value of the path loss amount that can be indicated through the MAC-CE. That is, the terminal may update the difference value of the path loss amount that can be indicated through the MAC-CE equally for the difference values ​​of the path loss amounts that can be the same or different, which are respectively set in one or more UL TCI states that can be indicated through the MAC-CE.

[0623] Additionally, the terminal may support simultaneous updating of the difference values ​​of path loss amounts set within multiple joint TCI states or UL TCI states. To this end, the terminal may receive upper layer signaling configured for each bandwidth segment, cell, or cell group.

[0624] - As an example, the terminal may be configured with simultaneousU-TCI-UpdateList1-r17, simultaneousU-TCI-UpdateList2-r17, simultaneousU-TCI-UpdateList3-r17, or simultaneousU-TCI-UpdateList4-r17 by the corresponding upper layer signaling, and each parameter may include the index of the serving cell. If a terminal receives a MAC-CE instructing to update a difference value of path loss for one or more joint TCI states or UL TCI states within a specific serving cell, and if an index of the corresponding serving cell is included in one or more upper layer signalings among simultaneousU-TCI-UpdateList1-r17, simultaneousU-TCI-UpdateList2-r17, simultaneousU-TCI-UpdateList3-r17, or simultaneousU-TCI-UpdateList4-r17, and the one or more upper layer signalings including the index of the corresponding serving cell include indices of one or more other serving cells, the terminal may equally apply the instruction information of the MAC-CE to one or more other serving cells included in the one or more upper layer signalings including the index of the corresponding serving cell. The terminal may report to the base station the terminal capability that means that the terminal can apply the above list to update the difference value of the path loss amount, and the information that may be included in the terminal capability signaling may include the maximum number of lists that the terminal can be configured with, and the maximum number of serving cells that may be included in the lists that the terminal can be configured with.The reporting unit for the terminal capability signaling may be per UE, per band, per band combination, per feature set, or per FSPC (feature set per component carrier).

[0625] - As another example, the terminal may be configured with one or more lists of one or more joint TCI states in the downlink bandwidth portion by the corresponding upper layer signaling. If the terminal receives a MAC-CE instructing to update the difference value of the path loss amount, if some or all of the one or more joint TCI states indicated in the MAC-CE are each included in the list of one or more joint TCI states, the terminal may update all joint TCI states in each list with the difference value of the path loss amount instructed to be updated by the MAC-CE.

[0626] ■ At this time, the number of the above lists set to the terminal may be limited to 1, or more than 1 may be set.

[0627] ■ In addition, the difference value of the path loss amount indicated to the terminal through MAC-CE may be 1, and the 1 may be applied equally to 1 or more joint TCI states indicated by the same MAC-CE. In this case, the terminal may expect that the field for the difference value of the path loss amount is located first in the MAC-CE, and then the fields for 1 or more joint TCI states exist, and the value indicated through the field for the difference value of the path loss amount located first may be commonly applied to all joint TCI states that may be indicated through the fields for 1 or more joint TCI states that exist thereafter.

[0628] ■ In addition, the difference value of the path loss amount indicated to the terminal through MAC-CE may be more than one, and each of the difference values ​​of one or more path losses may be applied to a subset of one or more joint TCI states indicated by the same MAC-CE. In this case, the terminal can expect that a field indicating one of the difference values ​​of one or more path losses is located first in the MAC-CE, and then a field for one or more joint TCI states to which the difference value of one path loss amount is applied exists, and then such field arrangement is repeated to configure the MAC-CE field.

[0629] ■ At this time, it can be considered that one or more joint TCI states included in the list of one or more joint TCI states have all received an initial setting for the difference value of the path loss amount through upper layer signaling. At this time, the initial setting value can include 0. If the terminal does not receive an initial setting for the difference value of the path loss amount for a specific joint TCI state, the terminal may not expect that such joint TCI state is included in the list of the joint TCI state. If the terminal does not receive an initial setting for the difference value of the path loss amount for a specific joint TCI state, the terminal may regard such joint TCI state as being the same as having the difference value of the path loss amount set to 0, and if such joint TCI state is included in the list of the joint TCI state, the terminal may apply a method of updating the difference value of the path loss amount through the corresponding MAC-CE for the corresponding joint TCI state.

[0630] ■ A terminal can report terminal capabilities to a base station, meaning that it supports the above list. Information that can be included in the terminal capability signaling may include the maximum number of lists that the terminal can configure and the maximum number of joint TCI states that can be included in the lists that the terminal can configure. The reporting unit of the terminal capability signaling may be per UE, per band, per band combination, per feature set, or per FSPC (feature set per component carrier).

[0631] ■ For example, if the terminal has set the first joint TCI state to the sixteenth joint TCI state through upper layer signaling, and has set the first joint TCI state list and the second joint TCI state list, and the first joint TCI state list includes the first joint TCI state to the eighth joint TCI state, and the second joint TCI state list includes the ninth joint TCI state to the sixteenth joint TCI state, it can be considered that the terminal receives a MAC-CE that updates the difference value of one path loss amount while including the indexes of the first joint TCI state and the ninth joint TCI state, the terminal can update not only the first joint TCI state and the ninth joint TCI state, but also the other joint TCI states in the first joint TCI state list including the first joint TCI state, and the other joint TCI states in the second joint TCI state list including the ninth joint TCI state, to the difference value of one path loss amount indicated by the MAC-CE.

[0632] ■ As another example, if the terminal receives the first joint TCI state to the sixteenth joint TCI state through upper layer signaling, and receives the first joint TCI state list and the second joint TCI state list, and the first joint TCI state list includes the first joint TCI state to the eighth joint TCI state, and the second joint TCI state list includes the ninth joint TCI state to the sixteenth joint TCI state, it can be considered a case. At this time, if the terminal receives a MAC-CE that updates the difference value of two path losses while including the indexes of the first joint TCI state and the ninth joint TCI state, and is instructed that the difference value of the first path loss is applied to the first joint TCI state and the difference value of the second path loss is applied to the ninth joint TCI state, the terminal can use the difference value of the first path loss to update not only the first joint TCI state but also the remaining other joint TCI states in the first joint TCI state list including the first joint TCI state, and can use the difference value of the second path loss to update not only the ninth joint TCI state but also the remaining other joint TCI states in the second joint TCI state list including the ninth joint TCI state.

[0633] - As another example, the terminal can be configured with a list of one or more UL TCI states in the uplink bandwidth section by the corresponding upper layer signaling. If the terminal receives a MAC-CE instructing to update the difference value of the path loss amount, if some or all of the one or more UL TCI states indicated in the MAC-CE are each included in the list of one or more UL TCI states, the terminal can update all UL TCI states in each list with the difference value of the path loss amount instructed to be updated by the MAC-CE.

[0634] ■ At this time, the number of the above lists set to the terminal may be limited to 1, or more than 1 may be set.

[0635] ■ In addition, the difference value of the path loss amount indicated to the terminal through MAC-CE may be 1, and the 1 may be applied equally to 1 or more UL TCI states indicated by the same MAC-CE. In this case, the terminal may expect that the field for the difference value of the path loss amount is located first in the MAC-CE, and then the fields for 1 or more UL TCI states exist, and the value indicated through the field for the difference value of the path loss amount located first may be commonly applied to all UL TCI states that may be indicated through the fields for 1 or more UL TCI states that exist thereafter.

[0636] ■ In addition, the difference value of the path loss amount indicated to the terminal through MAC-CE may be more than one, and each of the difference values ​​of one or more path losses may be applied to a subset of one or more UL TCI states indicated by the same MAC-CE. In this case, the terminal can expect that a field indicating one of the difference values ​​of one or more path losses is located first in the MAC-CE, and then a field for one or more UL TCI states to which the difference value of one path loss amount is to be applied exists, and then such field arrangement is repeated to configure the MAC-CE field.

[0637] ■ At this time, it can be considered that one or more UL TCI states included in the list of one or more UL TCI states have all received an initial setting for the difference value of the path loss amount through upper layer signaling. At this time, the initial setting value can include 0. If the terminal does not receive an initial setting for the difference value of the path loss amount for a specific UL TCI state, the terminal may not expect that such UL TCI state is included in the list of the UL TCI state. If the terminal does not receive an initial setting for the difference value of the path loss amount for a specific UL TCI state, the terminal may consider such UL TCI state to be the same as that the difference value of the path loss amount is set to 0, and if such UL TCI state is included in the list of the UL TCI state, the terminal may apply a method of updating the difference value of the path loss amount through the corresponding MAC-CE for the corresponding UL TCI state.

[0638] ■ A terminal can report terminal capabilities to a base station, meaning that it supports the above list. Information that can be included in the terminal capability signaling may include the maximum number of lists that the terminal can configure and the maximum number of UL TCI states that can be included in the lists that the terminal can configure. The reporting unit of the terminal capability signaling may be per UE, per band, per band combination, per feature set, or per FSPC (feature set per component carrier).

[0639] ■ For example, if a terminal is configured with the first UL TCI state to the sixteenth UL TCI state through upper layer signaling, and a first UL TCI state list and a second UL TCI state list are configured, and the first UL TCI state list includes the first UL TCI state to the eighth UL TCI state, and the second UL TCI state list includes the ninth UL TCI state to the sixteenth UL TCI state, it can be considered. At this time, if the terminal receives a MAC-CE that updates the difference value of one path loss amount while including the indexes of the first UL TCI state and the ninth UL TCI state, the terminal can update the difference value of one path loss amount indicated by the MAC-CE not only for the first UL TCI state and the ninth UL TCI state, but also for the remaining other UL TCI states in the first UL TCI state list including the first UL TCI state, and for the remaining other UL TCI states in the second UL TCI state list including the ninth UL TCI state.

[0640] ■ As another example, if a terminal is configured with the first UL TCI state to the sixteenth UL TCI state through upper layer signaling, and a first UL TCI state list and a second UL TCI state list are configured, and the first UL TCI state list includes the first UL TCI state to the eighth UL TCI state, and the second UL TCI state list includes the ninth UL TCI state to the sixteenth UL TCI state, it can be considered. At this time, if the terminal receives a MAC-CE that updates the difference value of two path losses while including the indexes of the first UL TCI state and the ninth UL TCI state, and is instructed that the difference value of the first path loss is applied to the first UL TCI state and the difference value of the second path loss is applied to the ninth UL TCI state, the terminal can update not only the first UL TCI state but also the remaining other UL TCI states in the first UL TCI state list including the first UL TCI state using the difference value of the first path loss, and can update not only the ninth UL TCI state but also the remaining other UL TCI states in the second UL TCI state list including the ninth UL TCI state using the difference value of the second path loss.

[0641] - As another example, the terminal may be configured with one or more joint TCI state lists or one or more UL TCI state lists as described above, and may additionally be configured with one or more lists of serving cells. When a terminal receives a MAC-CE indicating an update of a difference value of a path loss amount, if one or more joint TCI states or one or more UL TCI states indicated by the MAC-CE are included in one or more joint TCI state lists or one or more UL TCI state lists, the terminal may also update all other joint TCI states or all other UL TCI states in the one or more joint TCI state lists or one or more UL TCI state lists with the same difference value of a path loss amount indicated by the MAC-CE, and if a list of serving cells including the serving cell exists, the terminal may also update one or more identical joint TCI states or one or more UL TCI states in other serving cells included in the list of the serving cell with the same difference value of a path loss amount indicated by the MACC-E.If there is one or more joint TCI state lists or one or more UL TCI state lists including one or more joint TCI states or one or more UL TCI states indicated by MAC-CE in another serving cell included in the list of serving cells, the terminal may also update all other joint TCI states or all other UL TCI states in one or more joint TCI state lists or one or more UL TCI state lists including one or more joint TCI states or one or more UL TCI states indicated by MAC-CE in another serving cell included in the list of serving cells including the serving cell that received the MAC-CE, with the difference value of the same path loss amount indicated by the MAC-CE.

[0642] After the terminal receives the corresponding MAC-CE from the base station, 3 slots after the PUCCH transmission including HARQ-ACK information for the PDSCH including the corresponding MAC-CE, the terminal can update the d_P value, which is the difference value of the path loss amount set by the upper layer signaling, or the d_P'', which is the change amount of the d_P value, to the value received by the MAC-CE signaling and apply it when determining the uplink transmission power.

[0643] In the case where the terminal updates the difference value of the path loss amount to the value received by the MAC-CE signaling as in [Method 3-1], the terminal can update the difference value of the path loss amount relatively dynamically in addition to the method of setting it semi-statically, so it can be useful for compensating for the path loss amount when determining the transmission power of the terminal when the terminal has mobility. However, as described above, the terminal and the base station need to define a new MAC-CE signaling, the base station must be able to periodically measure the difference value of the path loss amount, and the delay time when exchanging information between TRPs may not be large.

[0644] [Method 3-2]

[0645] The terminal can receive a path loss difference value from the base station via upper-layer signaling. This path loss difference value may vary by bandwidth segment, or it may vary by cell, with the same value set for all bandwidth segments within a cell. If a path loss difference value is set, the terminal can expect a new field to be included in the DCI indicating whether to apply the path loss difference value.

[0646] The terminal can distinguish, through the new field in the DCI, whether the uplink transmission from the base station through the DCI is for a UL-only TRP or for a TRP capable of both uplink and downlink operations. The new field may be 1 bit, and if its value is 1, the difference value of the path loss amount may be applied when determining the path loss amount within the transmission power for the uplink transmission, and the uplink transmission may be regarded as for a UL-only TRP, and if its value is 0, the difference value of the path loss amount may not be applied for the uplink transmission, and the uplink transmission may be regarded as for a TRP capable of operating in both uplink and downlink.

[0647] Since the terminal can set and use the difference value of one path loss amount, the signaling exchange between the terminal and the base station can be relatively simplified from the perspective of managing the difference value of the path loss amount. In addition, depending on the characteristics of the integrated TCI state, when the terminal is instructed to enter a specific TCI state, it can be applied from a specific time and maintained until a new TCI state is instructed and applied. In this way, the terminal can dynamically switch, based on DCI, between uplink transmission for UL-only TRP and uplink transmission for TRP that can operate in both uplink and downlink without being instructed about a new TCI state. However, when considering the difference value of one path loss amount, there may be a problem if more than one UL-only TRP is considered.

[0648] The terminal can receive a path loss difference value set by the base station through upper layer signaling. The path loss difference value setting may vary by bandwidth part, or may vary by cell, so that the same value is set for all bandwidth parts within the cell. When the path loss difference value is set, the terminal can expect that a new field indicating whether the path loss difference value is applied is included in the DCI. Through the new field in the DCI, the terminal can distinguish whether the uplink transmission is for a UL-only TRP from an uplink transmission for a TRP that can operate both uplink and downlink through the DCI from the base station, and it can mean an additional offset of a specific value from the single path loss difference value set by upper layer signaling.

[0649] The above new field may be 2 bits, and if its value is 00, the difference value of the path loss amount set by the upper layer signaling may be applied when determining the path loss amount within the transmission power for the uplink transmission (i.e., it may be considered that no additional offset is applied from the difference value of the path loss amount set by the upper layer signaling). If its value is 01, 10, or 11, the terminal may assume that the additional offset from the difference value of the path loss amount set by the upper layer signaling is considered to determine the final difference value of the path loss amount, and if its value is 01, 10, or 11, -3dB, 1dB, or 3dB may be applied, respectively.

[0650] Alternatively, the new field in the DCI may be 2 bits, and if the value is 00, the difference value of the path loss amount may not be applied, and if the value is 11, the difference value of the path loss amount set by the upper layer signaling may be applied when determining the path loss amount within the transmission power for the uplink transmission (i.e., it may be considered that no additional offset is applied from the difference value of the path loss amount set by the upper layer signaling), and if the value is 01 or 10, the terminal may assume that an additional offset from the difference value of the path loss amount set by the upper layer signaling is considered to determine the final difference value of the path loss amount, and in the case of 01 or 10, -3dB or 3dB may be applied, respectively.

[0651] Since a terminal can receive and use a single path loss difference value while additionally compensating for the path loss difference value through DCI, it can utilize a relatively accurate path loss difference value compared to using only the value set by upper-layer signaling in cases where the terminal has high mobility. However, indicating such an accurate path loss difference value may have the disadvantage of increasing additional DCI overhead.

[0652] A terminal may receive one or more path loss difference values ​​from the base station via upper-layer signaling. These path loss difference values ​​may vary by bandwidth segment, or may be cell-specific, with the same value set for all bandwidth segments within a cell. If a path loss difference value is set, the terminal can expect a new field to be included in the DCI indicating whether to apply the path loss difference value.

[0653] The terminal can distinguish, through the new field in the DCI, whether the uplink transmission is for a UL-only TRP from the base station through the DCI or for an uplink transmission for a TRP capable of both uplink and downlink operations. The new field can be expressed as a number of bits that can express the number of difference values ​​of the configured path loss amount, and can convey a specific difference value of the path loss amount for each code point, and can mean that at least one of all code points does not apply the difference value of the path loss amount.

[0654] Since the terminal can set and use the difference values ​​of multiple path losses, from the perspective of managing the difference values ​​of path losses, signaling exchange between the terminal and the base station may be relatively increased compared to managing a single path loss amount. However, when considering the difference values ​​of multiple path losses, it may be advantageous to consider more than one UL-only TRP.

[0655] The terminal can use the above [Method 3-2] when transmitting at least one channel / signal among PUSCH, PUCCH, SRS, and PRACH. If the terminal uses the above [Method 3-2] when transmitting PRACH, the terminal can apply it to PRACH transmission that can be triggered by DCI format 1_0, and the base station and the terminal can define a new field in DCI format 1_0, and the terminal can be instructed of a difference value of one path loss amount through the new field. The terminal can receive N≥1 difference values ​​of path losses set in PRACH-config through upper layer signaling, and at this time, the bit length of the new field It can be, means the raising function can mean a logarithmic function with base 2.

[0656] A terminal may report terminal capability signaling to a base station, which means that it supports the above [Method 3-1] or [Method 3-2]. The terminal may define the terminal capability signaling as individual terminal capabilities, or may define different components within a single terminal capability signaling. The terminal may use one of the following methods as a reporting unit for the terminal capability signaling for the above [Method 3-1] or [Method 3-2]: per UE, per band, per band combination, per FS, and per FSPC (feature set per component carrier).

[0657] If the terminal reports terminal capability signaling to the base station, which means that it supports the above [Method 3-1] or [Method 3-2], the base station can set upper layer signaling to the terminal, and based on this, the terminal can perform operations for the above [Method 3-1] and / or [Method 3-2]. At this time, the upper layer signaling from the base station can be individually defined for the above [Method 3-1] or [Method 3-2], or can mean that the above [Method 3-1], the above [Method 3-2], or both the above [Method 3-1] and [Method 3-2] can be supported, depending on the value of one upper layer signaling.

[0658] The terminal may determine whether to apply the difference value of the path loss amount by considering at least one combination of [Method 3-1] or [Method 3-2] when performing a dynamic grant-based PUSCH transmission scheduled based on DCI, a Type-2 configured grant-based PUSCH transmission activated through DCI, a Type-1 configured grant-based PUSCH transmission configured through upper layer signaling, a PUCCH transmission, an SRS transmission, or a PRACH transmission.

[0659] As one embodiment of the present disclosure, a beam failure recovery operation considering a TRP that supports only uplink reception is described. This embodiment can be operated in combination with other embodiments within the present disclosure.

[0660] A terminal can operate by being connected to a serving cell composed of a TRP that supports only uplink reception and a TRP that enables both uplink and downlink operations (in particular, the serving cell may be a primary cell (PCell)). The terminal may receive BeamFailureRecoveryConfig, which is an upper layer signaling related to a beam failure recovery operation within an uplink bandwidth portion of the serving cell. The terminal may receive up to 48 PRACH-ResourceDedicatedBFRs, which are upper layer signaling used in a new candidate beam identification process during the beam failure recovery operation, and each of the PRACH-ResourceDedicatedBFRs may include information on a candidate beam RS. A candidate beam RS set may include up to 48 RSs, and the RSs may be periodic CSI-RSs or SSBs.

[0661] - When the upper layer of the terminal requests the terminal to report information on a new candidate beam, the terminal reports the index information and the L1-RSRP measurement value of one or more RSs among the RSs included in the candidate beam RS set that have an L1-RSRP value greater than a threshold set through upper layer signaling. If the RS is a CSI-RS, the terminal may consider the value obtained by applying the upper layer signaling powerControlOffsetSS to the received power of the CSI-RS as the final L1-RSRP measurement value and compare it with the RSRP threshold. The upper layer of the terminal can obtain information on a new beam with good channel conditions through the report on the candidate beam RS from the physical layer of the terminal.

[0662] - If the upper layer of the terminal obtains information about a new beam with a good channel condition exceeding the RSRP threshold from the physical layer of the terminal, the upper layer of the terminal can select one of the new beams with a good channel condition exceeding the RSRP threshold and transmit it to the physical layer. At this time, the index of the candidate beam RS transmitted by the upper layer of the terminal to the physical layer of the terminal can be named q_new.

[0663] - The physical layer of the terminal transmits a request signal for beam failure recovery to the base station based on the PRACH resource corresponding to the candidate beam RS received from the upper layer of the terminal.

[0664] - At this time, the terminal can arbitrarily decide on the PRACH transmission beam, and the easiest method to consider in terms of terminal implementation may be a method of transmitting in the beam direction in which the candidate beam RS connected to the corresponding PRACH was received.

[0665] - However, when a terminal is connected to a serving cell composed of a TRP capable of both uplink and downlink operations as described above and a TRP supporting only uplink reception, when the terminal transmits a PRACH for beam failure recovery, the performance of the beam failure detection RS between the TRP performing downlink operation and the terminal is very poor, and the TRP supporting only uplink reception will be located relatively closer than the TRP capable of both uplink and downlink operations. Therefore, when the PRACH transmission is transmitted to a TRP capable of only uplink reception, there may be an advantage in that the base station is more likely to successfully receive the PRACH when requesting beam failure recovery from the base station.

[0666] - For this purpose, the terminal and the base station can define a method for explicitly transmitting the PRACH transmission connected to the candidate beam RS for beam failure recovery operation to the TRP that supports only uplink reception. Even if the terminal transmits the PRACH resource connected to the candidate beam RS on its own to the TRP that supports only uplink reception, if the difference value of the path loss amount is not applied when transmitting the PRACH, when the PRACH is received in the TRP that supports only uplink reception, it may act as a large interference to other uplink signals. Therefore, it may be advantageous to both the terminal and the base station to explicitly define whether the PRACH transmission between the terminal and the base station is transmitted to the TRP that supports only uplink reception or the TRP that supports both uplink and downlink operations. For this purpose, the terminal and the base station can consider at least one combination of [Method 4-1], [Method 4-2], [Method 4-3], and [Method 4-4] below.

[0667] [Method 4-1]

[0668] A terminal can receive one or more path loss difference values ​​from a base station through upper layer signaling. At this time, the terminal can receive the upper layer signaling configuration in PRACH-ResourceDedicatedBFR, in the bandwidth section (for example, in PRACH-config, in BWP-UplinkDedicated, in BeamFailureRecoveryConfig), or in the serving cell (for example, in ServingCellConfig). The physical layer of the terminal can receive one of one or more candidate beam RSs from the upper layer of the terminal, and the index of the candidate beam RS received at this time can be referred to as q_new.

[0669] The upper layer of the terminal can transmit q_new to the physical layer of the terminal. In addition, the upper layer of the terminal can instruct the physical layer of the terminal as to whether or not to apply the difference value of the path loss amount configured through the upper layer signaling described above when transmitting a PRACH corresponding to the q_new to the physical layer of the terminal. At this time, the difference value of the path loss amount that the terminal can configure through the upper layer signaling may be one, and in this case, the upper layer of the terminal can notify the physical layer of the terminal of whether or not to apply the difference value of the path loss amount when transmitting a PRACH corresponding to q_new. Alternatively, the difference value of the path loss amount that the terminal can configure through the upper layer signaling may be more than one, and in this case, the upper layer of the terminal can notify the physical layer of the terminal of whether or not to apply the difference value of the path loss amount when transmitting a PRACH corresponding to q_new.

[0670] For example, a terminal can receive a path loss difference value within one or more PRACH-ResourceDedicatedBFRs, and when an upper layer of the terminal transmits a specific PRACH-ResourceDedicated to the physical layer of the terminal as q_new, the upper layer of the terminal can additionally notify whether to apply the path loss difference value included in the upper layer signaling of the corresponding q_new. If the physical layer of the terminal decides not to apply the path loss difference value from the upper layer of the terminal, the terminal can perform PRACH transmission regardless of the path loss difference value that only allows uplink reception. That is, even though the terminal recognizes that a TRP that only allows uplink reception is closer to the terminal during PRACH transmission, the path loss amount may be transmitted in accordance with a TRP that allows uplink and downlink operation.

[0671] [Method 4-2]

[0672] The terminal can expect that the upper layer signaling, PRACH-ResourceDedicatedBFR, includes up to two PRACH resource configurations. In this case, one PRACH resource (e.g., the first PRACH resource) may represent a PRACH transmission resource for a TRP that supports both uplink and downlink operations, and another PRACH resource (e.g., the second PRACH resource) may represent a PRACH transmission resource for a TRP that supports only uplink reception.

[0673] - At this time, the upper layer signaling related to the first PRACH resource may include ra-PreambleIndex, which is an upper layer signaling indicating a preamble index, and if the candidate beam RS is a CSI-RS, ra-OccasionList, which is an upper layer signaling indicating a transmission location of the PRACH, may be included.

[0674] - In addition, the upper layer signaling related to the second PRACH resource may include, in addition to the upper layer signaling related to the first PRACH resource, at least one of a difference value of path loss and an index of an uplink reference signal that can be referred to when determining a PRACH transmission beam. If the index of an uplink reference signal that can be referred to when determining the PRACH transmission beam is not included, the terminal may determine the PRACH transmission beam on its own, or may use an uplink transmission beam direction (i.e., a transmission / reception direction of a source RS of QCL-TypeD) of a TCI state that includes a non-zero difference value of path loss among one or more TCI states that the terminal is instructed to apply by the base station. If there is no TCI state that includes a non-zero path loss difference value among one or more TCI states that are instructed and applied to the terminal, the terminal may use the uplink transmission beam direction (i.e., the transmission / reception direction of the source RS of QCL-TypeD) of the TCI state having the lowest TCI state index among the instructed TCI states, the TCI state having the highest TCI state index, the first TCI state, or the second TCI state.

[0675] The upper layer of the terminal may, while transmitting information about q_new to the physical layer of the terminal, additionally transmit to the physical layer of the terminal which of up to two PRACH resources set in PRACH-ResourceDedicatedBFR, which is an upper layer signaling corresponding to q_new, will be used to perform PRACH transmission. That is, the terminal may establish a one-to-many connection relationship between the candidate beam RS and the PRACH resource by setting two PRACH resources in PRACH-ResourceDedicatedBFR, which is an upper layer signaling that provides information about a connection relationship between the candidate beam RS and the PRACH resource, and may determine, according to an instruction from the upper layer of the terminal, whether to perform PRACH transmission as a TRP capable of both uplink and downlink operations or as a TRP capable of only uplink reception.

[0676] [Method 4-3]

[0677] A terminal can be configured with one PRACH resource within PRACH-ResourceDedicatedBFR. The physical layer of the terminal can receive one of one or more candidate beam RSs from the upper layer of the terminal, and the index of the candidate beam RS received at this time can be referred to as q_new. The upper layer of the terminal can transmit q_new to the physical layer of the terminal and additionally transmit to the physical layer of the terminal whether to apply the difference value of the path loss amount when transmitting the corresponding PRACH.

[0678] - At this time, the difference value of the path loss amount to be applied when transmitting PRACH to TRP where the physical layer of the terminal supports only uplink reception may follow the value included in the TCI state that the terminal has been instructed to apply by the base station. If there is one or more TCI states that include the difference value of the path loss amount among one or more TCI states instructed to the terminal, the terminal may apply the difference value of the path loss amount in the TCI state with the lowest index among the instructed TCI states, the TCI state with the highest index, the first TCI state, or the second TCI state.

[0679] - By using the difference value of the path loss amount set within the TCI state applied and instructed to the terminal in this way, the terminal can perform PRACH transmission for the TRP on which the terminal is currently performing communication.

[0680] [Method 4-4]

[0681] A terminal can be configured with one PRACH resource within a PRACH-ResourceDedicatedBFR from a base station. The terminal can be configured with a path loss difference value applicable to the PRACH resources connected within the PRACH-ResourceDedicatedBFR. That is, a path loss difference value may or may not be configured within a single PRACH-ResourceDedicatedBFR. Therefore, the terminal can expect an increase in the maximum number of PRACH-ResourceDedicatedBFRs that can be configured from the base station. The increased number can range from a minimum of 1 to a maximum of 48, and in this case, a maximum of 96 PRACH-ResourceDedicatedBFRs can be configured. If a path loss difference value is configured within a specific PRACH-ResourceDedicatedBFR, the terminal can consider that the PRACH resource connected within the corresponding PRACH-ResourceDedicatedBFR is transmitted to a TRP that supports only uplink reception. If a path loss difference value is not set within a specific PRACH-ResourceDedicatedBFR, the terminal may consider that the PRACH resources connected within the PRACH-ResourceDedicatedBFR are transmitted to a TRP that can operate in uplink and downlink.

[0682] The terminal can be notified from the base station through at least one combination of upper layer signaling, MAC-CE signaling, and L1 signaling among at least one combination of [Method 4-1], [Method 4-2], [Method 4-3], and [Method 4-4], or can expect that it is fixedly defined in the standard. For example, the terminal can expect that [Method 4-1] is fixedly defined in the standard. For another example, the terminal can expect that one of the [Method 4-2] and [Method 4-3] is set as upper layer signaling, and can consider that the remaining method that is not set is not supported.

[0683] A terminal may report terminal capability signaling to a base station, which means that it supports at least one combination of [Method 4-1], [Method 4-2], [Method 4-3], and / or [Method 4-4]. The terminal may define the terminal capability signaling as individual terminal capabilities, or may define different components within a single terminal capability signaling. The terminal may use one of per UE, per band, per band combination, per FS, and per FSPC (feature set per component carrier) as a reporting unit for the terminal capability signaling for [Method 4-1], [Method 4-2], [Method 4-3], and / or [Method 4-4].

[0684] If the terminal reports terminal capability signaling to the base station, which means that it supports [Method 4-1], [Method 4-2], [Method 4-3], or / and [Method 4-4], the base station can set up upper layer signaling to the terminal, and based on this, the terminal can perform operations for [Method 4-1], [Method 4-2], [Method 4-3], or / and [Method 4-4]. At this time, the upper layer signaling from the base station may be individually defined for the above [Method 4-1], [Method 4-2], [Method 4-3], or / and [Method 4-4], or may mean that the above [Method 4-1], [Method 4-2], [Method 4-3], or [Method 4-4], or all of the above [Method 4-1], [Method 4-2], [Method 4-3], and [Method 4-4] are supported depending on the value of one upper layer signaling.

[0685] As one embodiment of the present disclosure, a beam failure recovery response from a base station that can be received by a terminal after a beam failure recovery request based on a PRACH transmission by the terminal and a subsequent uplink transmission method of the terminal are described. This embodiment can be operated in combination with other embodiments of the present disclosure.

[0686] Starting from the 4th slot after the aforementioned PRACH transmission, the terminal can monitor the search space for the recoverySearchspace, which can be configured through upper layer signaling. In the search space, starting from 28 symbols after the terminal receives the first PDCCH, the terminal can perform uplink transmission using the default transmission power parameter during uplink transmission. The specific default transmission power parameter may be as follows.

[0687] - When transmitting PUSCH, PUCCH, and SRS following the indicated TCI state (for example, when followUnifiedTCI-StateSRS-r17 or / and applyIndicatedTCI-State-r18 are set in the upper layer signaling SRS resource set), the terminal may transmit using the transmission beam direction used in the most recently transmitted PRACH transmission, and may use the path loss measurement reference signal by replacing it with q_new.

[0688] - When transmitting PUSCH, the terminal may transmit using p0, alpha, and closed-loop power control loops with values ​​set in p0AlphaSetforPUSCH having the ul-powercontrolId with the lowest index among those set in the PCell or PSCell.

[0689] - When transmitting PUCCH, the terminal can transmit using the value set in p0AlphaSetforPUCCH with the ul-powercontrolId of the lowest index among those set in the PCell or PSCell, p0, the closed circuit power control loop.

[0690] - When transmitting PUSCH, the terminal may transmit using p0, alpha, and closed-loop power control loops using the values ​​set in p0AlphaSetforSRS having the ul-powercontrolId with the lowest index among those set in the PCell or PSCell.

[0691] A terminal can be connected to and operate with a base station that is configured with a TRP that can operate in both uplink and downlink and a TRP that can only receive uplink. In such a base station operation scenario, the terminal and the base station can communicate in a single TRP manner or a multi-TRP manner. Since the terminal can determine a beam failure situation by assessing the performance of the downlink control channel, the terminal can check a beam failure situation for the link between the terminal and a TRP that can operate in both uplink and downlink, but cannot check a beam failure situation for the link between the terminal and a TRP that can only receive uplink.

[0692] - When a terminal communicates in a single TRP manner, the terminal may be instructed to one joint TCI state, one DL TCI state, and / or one UL TCI state. If the one UL TCI state to which the terminal is instructed is for a TRP that supports only uplink reception, the terminal may still consider the link with the TRP that supports only uplink reception as available even if the terminal determines that the connection with the TRP that can operate in both uplink and downlink has been lost due to a beam failure situation. Therefore, the terminal may operate in one of the following manners.

[0693] [Method S1]

[0694] ■ If the UL TCI state (in FR1 or FR2) or joint TCI state (in FR1) that the terminal is instructed to is a TCI state that applies to a TRP that supports only uplink reception (for example, a non-zero path loss difference value is set in the TCI state, or a path loss difference value with a value of 0 is set but is updated later through MAC-CE so that the path loss difference value that the terminal currently recognizes for the TCI state is a different value from the initial upper layer signaling setting value of 0), the terminal transmits, as described above, after 28 symbols after receiving the first PDCCH in the search space for the recoverySearchspace that can be monitored from 4 slots after the slot in which the PRACH transmission was performed, PUSCH, PUCCH, and SRS following the instructed TCI state (for example, if followUnifiedTCI-StateSRS-r17 or / and applyIndicatedTCI-State-r18 are set in the upper layer signaling SRS resource set). Instead of aligning the beam direction with the most recently transmitted PRACH transmission or following the set of transmit power parameters with the lowest index, the terminal can follow the indicated UL TCI state or joint TCI state. That is, the terminal can follow the indicated TCI state without using the default transmit power parameter for uplink in the beam failure situation. Since the terminal performs the determination of beam failure based on the downlink reference signal, if the TCI state is indicated and applied for a TRP that supports only uplink reception, the terminal can use a more optimized transmission beam and transmit power parameter by not performing the default operation.

[0695] [Method S2]

[0696] ■ If the UL TCI state (in FR1 or FR2) or joint TCI state (in FR1) that the UE is instructed to is a TCI state that applies to a TRP that can operate in both uplink and downlink (for example, if the path loss difference value is not set in the TCI state, or if the path loss difference value with a value of 0 is set, or if the path loss difference value with a value other than 0 is set but is updated later through MAC-CE and the path loss difference value that the UE currently recognizes for the TCI state is 0, different from the initial upper layer signaling setting value), the UE receives the first PDCCH in the search space for the recoverySearchspace that can be monitored from 4 slots after the slot in which the PRACH transmission was performed, and then 28 symbols after the PUSCH, PUCCH, and SRS following the instructed TCI state (for example, followUnifiedTCI-StateSRS-r17 or / and in the SRS resource set that is the upper layer signaling) in the case of a beam failure situation. When applyIndicatedTCI-State-r18 is set), when transmitting, the transmission beam direction is not adjusted to the same as the most recently transmitted PRACH transmission as described above, or the set of transmission power parameters with the lowest index is not used, but the uplink transmission can be performed based on the TCI state with the lowest index, which has a non-zero path loss difference value among the TCI states activated for the terminal, or which is updated through MAC-CE even if the initial setting value was 0, and the path loss difference value that the terminal currently recognizes for the corresponding TCI state is non-zero.That is, in the above beam failure situation, the terminal may not use the default transmission power parameter for uplink, but may follow the transmission power parameter set in a specific TCI state among those corresponding to a TRP that only supports uplink reception among the activated TCI states. Since the terminal performs the determination of beam failure based on the downlink reference signal, even if it is not the indicated TCI state, if the TCI state is indicated and applied to a TRP that supports only uplink reception, the terminal may use a more optimized transmission beam and transmission power parameter by not performing the default operation.

[0697] [Method S3]

[0698] ■ If the UL TCI state (in FR1 or FR2) or joint TCI state (in FR1) that the terminal is instructed to is a TCI state that is applicable to a TRP that can operate in both uplink and downlink (for example, if the path loss difference value is not set in the TCI state, or if the path loss difference value with a value of 0 is set, or if the path loss difference value with a value other than 0 is set but is updated later through MAC-CE and the path loss difference value that the terminal currently recognizes for the TCI state is 0, different from the initial upper layer signaling setting value), or if the TCI state is applicable to a TRP that only supports uplink reception (for example, if the path loss difference value with a value other than 0 is set in the TCI state, or if the path loss difference value with a value of 0 is set but is updated later through MAC-CE and the path loss difference value that the terminal currently recognizes for the TCI state is different from the initial upper layer signaling setting value 0), the terminal shall transmit the PRACH at 4 times from the slot in which the PRACH transmission was performed in the event of a beam failure. After receiving the first PDCCH in the search space for the recoverySearchspace that can be monitored from the slot onwards, after 28 symbols, when transmitting PUSCH, PUCCH, and SRS following the indicated TCI state (for example, when followUnifiedTCI-StateSRS-r17 or / and applyIndicatedTCI-State-r18 are set in the upper layer signaling SRS resource set), the transmit beam direction and basic transmit power parameters that can be determined according to specific rules can be used.Since the link status between the terminal and the TRP that only supports uplink reception cannot be known from the terminal's perspective and can only be determined by the base station, the terminal can take the most conservative approach and use a specific basic transmission method by considering a situation in which all TRPs have insufficient links. For this operation, the terminal can decide on the transmission beam direction by considering at least one combination of [Method 5-1] or [Method 5-2] below, and can use the basic transmission power parameter by considering at least one combination of [Method 6-1], [Method 6-2], or [Method 6-3] below.

[0699] - When a terminal communicates in a multi-TRP manner, the terminal may be instructed to a maximum of two joint TCI states, or a maximum of two DL TCI states and / or a maximum of two UL TCI states.

[0700] [Method M1]

[0701] ■ If the terminal is instructed to one of two UL TCI states (in FR1 or FR2) or two joint TCI states (in FR1), and one of them (for example, the first TCI state) is applied to a TRP that can operate in both uplink and downlink, and the other (for example, the second TCI state) is a TCI state that is applied to a TRP that supports only uplink reception (for example, a non-zero path loss difference value is set in the corresponding TCI state, or a path loss difference value with a value of 0 is set but is later updated through MAC-CE so that the path loss difference value that the terminal currently recognizes for the corresponding TCI state is different from the initial upper layer signaling setting value of 0), the terminal receives the first PDCCH in the search space for the recoverySearchspace that can be monitored from 4 slots after the slot in which the PRACH transmission was performed, and then 28 symbols after that, PUSCH, PUCCH, and SRS following the indicated TCI state. (For example, when followUnifiedTCI-StateSRS-r17 or / and applyIndicatedTCI-State-r18 are set in the SRS resource set, which is the upper layer signaling), when transmitting, the transmission parameters for the uplink channels and signals (for example, PUSCH, PUCCH transmitted based on a PUCCH resource set through upper layer signaling so that the second TCI state among the indicated TCI states is applied, and SRS transmitted based on an SRS resource within the SRS resource set through upper layer signaling so that the second TCI state among the indicated TCI states is applied) are (for example, a difference value of path loss, a transmission beam direction, a path loss reference signal,(Transmission power parameters, etc.) are maintained, and uplink channels and signals transmitted with the first TCI state applied (e.g., PUSCH, PUCCH transmitted based on a PUCCH resource set through upper layer signaling to apply the first TCI state among the indicated TCI states, and SRS transmitted based on an SRS resource in an SRS resource set through upper layer signaling to apply the first TCI state among the indicated TCI states) can be transmitted using q_new as a path loss amount reference signal and a set of transmission power parameters with the lowest index, while matching the transmission beam direction to the most recently transmitted PRACH transmission as described above. That is, the terminal can use the default transmission power parameter for the uplink for a link for a TRP that can operate in both uplink and downlink in the beam failure situation, and can follow the second TCI state indicated to the terminal without using the default transmission power parameter for a TRP that can receive uplink. Since the terminal determines whether a beam fails based on a downlink reference signal, the link between the terminal and the TRP capable of operating in both uplink and downlink is regarded as a beam failure situation and uses the default transmission power parameter and transmission beam direction, but for the link with the TRP that supports only uplink reception, the terminal does not perform the default operation by using the TCI state that was previously indicated and applied, thereby using more optimized transmission beam and transmission power parameters. For this operation, the terminal can decide on the transmission beam direction by considering at least one combination of [Method 5-1] or [Method 5-2] below, and can use the default transmission power parameter by considering at least one combination of [Method 6-1], [Method 6-2], or [Method 6-3] below.

[0702] [Method M2]

[0703] ■ If the terminal is instructed to one of two UL TCI states (in FR1 or FR2) or two joint TCI states (in FR1), and one of them (for example, the first TCI state) is applied to a TRP that can operate in both uplink and downlink, and the other (for example, the second TCI state) is a TCI state that is applied to a TRP that supports only uplink reception (for example, a non-zero path loss difference value is set in the corresponding TCI state, or a path loss difference value with a value of 0 is set but is later updated through MAC-CE so that the path loss difference value that the terminal currently recognizes for the corresponding TCI state is different from the initial upper layer signaling setting value of 0), the terminal receives the first PDCCH in the search space for the recoverySearchspace that can be monitored from 4 slots after the slot in which the PRACH transmission was performed, and then 28 symbols after that, PUSCH, PUCCH, and SRS following the indicated TCI state. (For example, when followUnifiedTCI-StateSRS-r17 or / and applyIndicatedTCI-State-r18 are set in the upper layer signaling SRS resource set), when transmitting, the uplink channels and signals transmitted by applying the first TCI state and the second TCI state can be transmitted using the transmission beam direction, the path loss reference signal, and the basic transmission power parameters as described above. Since the terminal may not be able to identify a case where the link performance between a TRP capable of only uplink reception and the terminal is poor, and this can be identified only by the base station, the basic transmission power parameter determination method can be applied to both the link between a TRP capable of both uplink and downlink and the link between a TRP capable of only uplink reception and the terminal in a conservative manner.For this operation, the terminal can determine the transmission beam direction by considering at least one combination of [Method 5-1] or [Method 5-2] below, and can use the basic transmission power parameter by considering at least one combination of [Method 6-1], [Method 6-2], or [Method 6-3] below.

[0704] The terminal can be notified from the base station through at least one combination of upper layer signaling, MAC-CE signaling, and L1 signaling for at least one combination of [Method S1], [Method S2], [Method S3], [Method M1], and / or [Method M2], or can expect that it is fixedly defined in the standard. For example, the terminal can expect that [Method S1], [Method S2], and [Method M1] are fixedly defined in the standard. For another example, the terminal can expect that [Method S3] is set as upper layer signaling, and if it is not set, it can expect that [Method S1] and [Method S2] are applied and operated. In addition, the terminal can expect that [Method M2] is set as upper layer signaling, and if it is not set, it can expect that [Method M1] is applied and operated.

[0705] A terminal may report terminal capability signaling to a base station, which means that it supports at least one combination of [Method S1], [Method S2], [Method S3], [Method M1], and / or [Method M2]. The terminal may define the terminal capability signaling as individual terminal capabilities, or may define different components within a single terminal capability signaling. The terminal may use one of per UE, per band, per band combination, per FS, and per FSPC (feature set per component carrier) as a reporting unit for the terminal capability signaling for the [Method S1], [Method S2], [Method S3], [Method M1], and / or [Method M2].

[0706] If the terminal reports terminal capability signaling to the base station, which means that the terminal supports [Method S1], [Method S2], [Method S3], [Method M1], or / and [Method M2], the base station can set up upper layer signaling to the terminal, and based on this, the terminal can perform operations for [Method S1], [Method S2], [Method S3], [Method M1], or / and [Method M2]. At this time, the upper layer signaling from the base station may be individually defined for the above [Method S1], [Method S2], [Method S3], [Method M1], or / and [Method M2], or may mean that the above [Method S1], [Method S2], [Method S3], [Method M1], or [Method M2], or all of the above [Method S1], [Method S2], [Method S3], [Method M1], and [Method M2] are all supported, depending on the value of one upper layer signaling.

[0707] If a terminal performs a PRACH transmission corresponding to q_new selected by the terminal as described above for a beam failure recovery request, the terminal may monitor a search space regarding recoverySearchspace that can be configured by upper layer signaling starting from 4 slots after the PRACH transmission. In the search space, when transmitting uplink starting from 28 symbols after the terminal receives the first PDCCH, the terminal may determine a basic transmission power parameter by considering a TRP that can operate in uplink and downlink and a TRP that can only receive uplink.

[0708] When transmitting PUSCH, PUCCH, and SRS following the indicated TCI state (for example, when followUnifiedTCI-StateSRS-r17 or / and applyIndicatedTCI-State-r18 are set in the upper layer signaling SRS resource set), the terminal may consider a combination of at least one of the following methods to determine the transmission beam direction.

[0709] [Method 5-1]

[0710] The terminal can transmit using the transmission beam direction used in the most recently transmitted PRACH transmission.

[0711] - For example, the PRACH transmission may have been transmitted as a TRP that only allows uplink reception because the difference value of the path loss is applied, or it may have been transmitted as a TRP that allows both uplink and downlink operations because the difference value of the path loss is not applied.

[0712] - As another example, the most recently transmitted PRACH may explicitly mean a PRACH transmission connected to q_new for the beam failure recovery request, or may be a PRACH transmitted additionally after a transmission for the PRACH connected to q_new for the beam failure recovery request.

[0713] - As another example, if a PRACH transmission connected to q_new for a ...

Claims

In a method performed by a terminal of a communication system, A step of receiving information about a bandwidth part (BWP) including one or more transmission configuration indication (TCI) state settings from a base station; A step of calculating a first path loss value based on a first reference signal or a second reference signal; A step of identifying the transmission power of an uplink signal based on the first path loss value; and A step of transmitting the uplink signal to a base station based on the transmission power is included, A method characterized in that whether the first reference signal is received is determined based on whether at least one TCI state setting among the one or more TCI state settings includes a path loss offset. In the first paragraph, If at least one TCI state setting among the one or more TCI state settings includes the path loss offset, the first reference signal is not received; A method characterized in that the first path loss value is calculated based on the second path loss value calculated based on the second reference signal and the path loss offset. In the first paragraph, If none of the above one or more TCI state settings include the path loss offset, the first reference signal is received, A method characterized in that the first path loss value is calculated based on the first reference signal. In the first paragraph, The above first reference signal is associated with a first transmission and reception point (TRP), A method characterized in that the second reference signal is associated with a second TRP. In a method performed by a base station of a communication system, A step of transmitting information about a bandwidth part (BWP) including one or more transmission configuration indication (TCI) state settings to a terminal; and A step of receiving an uplink signal from the terminal based on a transmission power associated with a first pathloss value, The above first path loss value is based on the first reference signal or the second reference signal, A method characterized in that whether or not to transmit the first reference signal is determined based on whether at least one TCI state setting among the one or more TCI state settings includes a path loss offset. In paragraph 5, If at least one TCI state setting among the one or more TCI state settings includes the path loss offset, the first reference signal is not transmitted; A method characterized in that the first path loss value is based on the second path loss value based on the second reference signal and the path loss offset. In paragraph 5, If none of the above one or more TCI state settings include the path loss offset, the first reference signal is transmitted; A method characterized in that the first path loss value is based on the first reference signal. In paragraph 5, The above first reference signal is associated with a first transmission and reception point (TRP), A method characterized in that the second reference signal is associated with a second TRP. At the terminal of the communication system, At least one transceiver; At least one processor communicatively connected to at least one transceiver; and Communicably connected to at least one processor, and executable individually or in any combination of said at least one processor, so that said terminal Receive information about a bandwidth part (BWP) including one or more transmission configuration indication (TCI) state settings from a base station, Calculate the first path loss value based on the first reference signal or the second reference signal, Identify the transmission power of the uplink signal based on the above first path loss value, A memory storing a command to transmit the uplink signal to a base station based on the transmission power, A terminal characterized in that whether the first reference signal is received is determined based on whether at least one TCI state setting among the one or more TCI state settings includes a path loss offset. In paragraph 9, If at least one TCI state setting among the one or more TCI state settings includes the path loss offset, the first reference signal is not received; A terminal characterized in that the first path loss value is calculated based on the second path loss value calculated based on the second reference signal and the path loss offset. In paragraph 9, If none of the above one or more TCI state settings include the path loss offset, the first reference signal is received, A terminal characterized in that the first path loss value is calculated based on the first reference signal. In paragraph 9, The above first reference signal is associated with a first transmission and reception point (TRP), A terminal characterized in that the second reference signal is associated with a second TRP. In the base station of a communication system, At least one transceiver; At least one processor communicatively connected to at least one transceiver; and Communicably connected to at least one processor, and executable individually or in any combination of said at least one processor, so that said base station Transmits information about a bandwidth part (BWP) including one or more transmission configuration indication (TCI) state settings to the terminal, A memory storing a command for receiving an uplink signal from the terminal based on a transmission power associated with a first pathloss value, The above first path loss value is based on the first reference signal or the second reference signal, A base station, characterized in that whether or not to transmit the first reference signal is determined based on whether at least one TCI state setting among the one or more TCI state settings includes a path loss offset. In Article 13, If at least one TCI state setting among the one or more TCI state settings includes the path loss offset, the first reference signal is not transmitted; A base station, characterized in that the first path loss value is based on the second path loss value based on the second reference signal and the path loss offset. In Article 13, If none of the above one or more TCI state settings include the path loss offset, the first reference signal is transmitted; A base station, characterized in that the first path loss value is based on the first reference signal.

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