Method and apparatus for transmitting or receiving demodulation reference signal in wireless communication system

Abstract

A user equipment (UE) in a wireless communication system is provided. The UE includes a transceiver, and a controller coupled with the transceiver, the controller configured to transmit, to a base station, first UE capability information indicating supported demodulation reference signal (DMRS) types for a downlink and second UE capability information indicating supported enhanced DMRS types for a physical downlink shared channel (PDSCH), transmit, to the base station, third UE capability information including a value indicating a maximum number of DMRS types for the PDSCH across all downlink control information (DCI) formats, and receive, from the base station, a DMRS for the PDSCH according to at least one DMRS type among the supported DMRS types and the supported enhanced DMRS types, wherein a number of the at least one DMRS type is equal to or less than the maximum number of DMRS types.

Description

Technical Field

[0001] This disclosure relates to the operation of terminals and base stations in a wireless communication system. More specifically, this disclosure relates to a method for transmitting or receiving downlink demodulation reference signals in a wireless communication system, and an apparatus capable of performing the method. Background Technology

[0002] Fifth-generation (5G) mobile communication technology defines a wide frequency band, enabling high transmission rates and new services. It can be implemented not only in the "below 6 GHz" band, such as 3.5 GHz, but also in the "above 6 GHz" band, including 28 GHz and 39 GHz, known as mmWave. Furthermore, sixth-generation (6G) mobile communication technology (called Super 5G systems) has been considered for implementation in terahertz bands (e.g., the 95 GHz to 3 THz band) to achieve transmission rates fifty times faster than 5G and ultra-low latency one-tenth that of 5G.

[0003] At the outset of 5G mobile communication technology development, standardization was underway regarding beamforming and massive MIMO to support services and meet performance requirements associated with enhanced mobile broadband (eMBB), ultra-reliable low-latency communication (URLLC), and massive machine-type communication (mMTC). This standardization aimed to mitigate radio wave path loss in millimeter waves and increase radio wave transmission distance; support parameter sets for dynamic operation (e.g., operating multiple subcarrier spacings) to efficiently utilize millimeter wave resources and time slot formats; initial access technologies to support multi-beam transmission and broadband; the definition and operation of bandwidth portions (BWP); new channel decoding methods (such as low-density parity-check (LDPC) codes for large data transmissions and polar codes for highly reliable transmission of control information); L2 preprocessing; and network slicing for providing dedicated networks for specific services.

[0004] Currently, given the services supported by 5G mobile communication technology, discussions are underway regarding improvements and performance enhancements to the initial 5G mobile communication technology. Physical layer standardization for technologies such as Vehicle-to-Everything (V2X) is also in place, designed to assist autonomous vehicle driving decisions based on information about the vehicle's location and status transmitted by the vehicle, and to enhance user convenience. This includes NR-U (New Radio Unlicensed) systems operating in unlicensed frequency bands, NR User Equipment (UE) Energy Saving, and Non-Terrestrial Networks (NTN), which provide coverage and positioning for UE-satellite direct communication in areas where communication with terrestrial networks is unavailable.

[0005] Furthermore, standardization is ongoing for technologies within the air interface architecture / protocol, such as the Industrial Internet of Things (IIoT) for supporting new services through interoperability and convergence with other industries, Integrated Access and Backhaul (IAB) for providing nodes for network service area extension by supporting wireless backhaul and access links in an integrated manner, mobility enhancements including conditional handover and Dual Active Protocol Stack (DAPS) handover, and two-step random access (two-step RACH for NR) for simplifying the random access process. Standardization is also underway for 5G baseline architectures (e.g., service-based architectures or service-based interfaces) for combining Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) technologies, as well as system architectures / services for Mobile Edge Computing (MEC) based on UE location reception services.

[0006] With the commercialization of 5G mobile communication systems, the already exponentially growing number of connected devices will be connected to the communication network, thus necessitating enhanced functionality and performance of 5G mobile communication systems as well as integrated operation of connected devices. To this end, new research related to extended reality (XR) has been arranged to effectively support augmented reality (AR), virtual reality (VR), mixed reality (MR), etc., by leveraging artificial intelligence (AI) and machine learning (ML), AI service support, metaspace service support, and drone communication to improve 5G performance and reduce complexity.

[0007] Furthermore, this development of 5G mobile communication systems will not only serve as the foundation for developing new waveforms for providing terahertz band coverage in 6G mobile communication technologies, such as multi-antenna transmission technologies like full-dimensional MIMO (FD-MIMO), array antennas, and massive MIMO; metamaterial-based lenses and antennas for improving terahertz band signal coverage; high-dimensional spatial multiplexing technologies using orbital angular momentum (OAM); and reconfigurable smart surfaces (RIS); it will also serve as the foundation for developing full-duplex technologies to improve the frequency efficiency of 6G mobile communication technologies and enhance system networks; AI-based communication technologies to achieve system optimization by leveraging satellites and artificial intelligence (AI) from the design phase and internalizing end-to-end AI support capabilities; and next-generation distributed computing technologies to achieve services with complexity levels exceeding the operational capabilities of UEs by utilizing ultra-high-performance communication and computing resources.

[0008] With the advancements in wireless communication systems as described above, a variety of services can be provided, and therefore a smooth way of delivering these services is needed.

[0009] The above information is presented as background information only to aid in understanding this disclosure. No determination or assertion is made regarding whether any of the above content can be used as prior art with respect to this disclosure. Summary of the Invention

[0010] Solution to the problem

[0011] The aspects of this disclosure will at least address the aforementioned problems and / or disadvantages, and provide at least the following advantages. Therefore, one aspect of this disclosure is to provide apparatus and methods capable of effectively providing services in a wireless communication system.

[0012] Additional aspects will be set forth in part in the description which follows, and in part will be apparent from the description, or may be learned by practicing the embodiments presented.

[0013] According to one aspect of this disclosure, a user equipment (UE) is provided in a wireless communication system. The UE includes: a transceiver; a memory storing one or more computer programs; and one or more processors communicatively coupled to the transceiver and the memory, wherein the one or more programs include computer-executable instructions that, when executed individually or jointly by the one or more processors, cause the UE to: transmit to a base station first UE capability information indicating supported demodulation reference signal (DMRS) types for downlink and second UE capability information indicating supported enhanced DMRS types for physical downlink shared channel (PDSCH); transmit to the base station third UE capability information including a value indicating a maximum number of DMRS types for PDSCH across all downlink control information (DCI) formats; and receive DMRS for PDSCH from the base station according to at least one of the supported DMRS types and supported enhanced DMRS types, wherein the number of at least one DMRS type is equal to or less than the maximum number of DMRS types.

[0014] According to one aspect of this disclosure, a base station in a wireless communication system is provided. The base station includes: a transceiver; a memory storing one or more computer programs; and one or more processors communicatively coupled to the transceiver and the memory, wherein the one or more programs include computer-executable instructions that, when executed individually or jointly by the one or more processors, cause the base station to: receive from a user equipment (UE) first UE capability information indicating supported demodulation reference signal (DMRS) types for downlink and second UE capability information indicating supported enhanced DMRS types for physical downlink shared channel (PDSCH); receive from the UE third UE capability information including a value indicating a maximum number of DMRS types for PDSCH across all downlink control information (DCI) formats; and transmit DMRS for PDSCH to the UE according to at least one of the supported DMRS types and supported enhanced DMRS types, wherein the number of at least one DMRS type is equal to or less than the maximum number of DMRS types.

[0015] According to one aspect of this disclosure, a method performed by a user equipment (UE) in a wireless communication system is provided. The method includes: transmitting to a base station first UE capability information indicating supported demodulation reference signal (DMRS) types for downlink and second UE capability information indicating supported enhanced DMRS types for physical downlink shared channel (PDSCH); transmitting to the base station third UE capability information including a value indicating a maximum number of DMRS types for PDSCH across all downlink control information (DCI) formats; and receiving from the base station DMRS for PDSCH according to at least one of the supported DMRS types and supported enhanced DMRS types, wherein the number of at least one DMRS type is equal to or less than the maximum number of DMRS types.

[0016] According to one aspect of this disclosure, a method performed by a base station in a wireless communication system is provided. The method includes: receiving from a user equipment (UE) first UE capability information indicating supported demodulation reference signal (DMRS) types for downlink and second UE capability information indicating supported enhanced DMRS types for the physical downlink shared channel (PDSCH); receiving from the UE third UE capability information including a value indicating a maximum number of DMRS types for the PDSCH across all downlink control information (DCI) formats; and transmitting DMRS for the PDSCH to the UE according to at least one of the supported DMRS types and the supported enhanced DMRS types, wherein the number of at least one DMRS type is equal to or less than the maximum number of DMRS types.

[0017] Other aspects, advantages, and salient features of this disclosure will become clear to those skilled in the art from the following detailed description of various embodiments disclosed in conjunction with the accompanying drawings. Attached Figure Description

[0018] The above and other aspects, features and advantages of certain embodiments of this disclosure will become clearer from the following description taken in conjunction with the accompanying drawings, in which:

[0019] Figure 1 The basic structure of the time-frequency domain in a wireless communication system according to an embodiment of the present disclosure is shown;

[0020] Figure 2 The structure of frames, subframes, and time slots in a wireless communication system according to embodiments of the present disclosure is shown;

[0021] Figure 3 An example of bandwidth configuration in a wireless communication system according to an embodiment of the present disclosure is shown;

[0022] Figure 4 An example of the configuration of the control resource set of the downlink control channel in a wireless communication system according to an embodiment of the present disclosure is shown;

[0023] Figure 5A The structure of a downlink control channel in wireless communication according to an embodiment of the present disclosure is shown;

[0024] Figure 5B This illustration shows an embodiment of the present disclosure in a wireless communication system in which, in terms of span, a UE may have multiple physical downlink control channel (PDCCH) monitoring opportunities within a time slot;

[0025] Figure 6 An example of discontinuous reception (DRX) operation in a wireless communication system according to an embodiment of the present disclosure is shown;

[0026] Figure 7 An example of base station beam allocation configured according to TCI state in a wireless communication system according to an embodiment of the present disclosure is shown;

[0027] Figure 8 An example of a method for TCI state allocation of PDCCH in a wireless communication system according to an embodiment of the present disclosure is shown;

[0028] Figure 9 The TCI indication MACCE signaling structure for PDCCH DMRS in a wireless communication system according to an embodiment of the present disclosure is shown.

[0029] Figure 10An example of beam configuration regarding the control resource set and search space in a wireless communication system according to embodiments of the present disclosure is shown;

[0030] Figure 11 An example of a method for transmitting / receiving data in a wireless communication system, according to an embodiment of the present disclosure, is shown;

[0031] Figure 12 An example of a method for a UE to select a set of receivable control resources by considering priorities when receiving a downlink control channel in a wireless communication system, according to an embodiment of the present disclosure, is shown.

[0032] Figure 13 An example of time-domain resource allocation for PDSCH in a wireless communication system according to an embodiment of the present disclosure is shown;

[0033] Figure 14 An example of time-domain resource allocation for PDSCH in a wireless communication system according to an embodiment of the present disclosure is shown;

[0034] Figure 15 An example of time-domain resource allocation for data channels and control channels based on subcarrier spacing is shown in a wireless communication system according to an embodiment of the present disclosure;

[0035] Figure 16 The process of beam configuration and activation of PDSCH in a wireless communication system according to an embodiment of the present disclosure is illustrated;

[0036] Figure 17 The radio protocol structures of a base station and a UE in a wireless communication system according to embodiments of the present disclosure are shown in single-cell, carrier aggregation, and dual connectivity scenarios;

[0037] Figure 18 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 is shown;

[0038] Figure 19 An example of downlink control information (DCI) configuration for cooperative communication in a wireless communication system according to an embodiment of the present disclosure is shown;

[0039] Figure 20 An enhanced PDSCH TCI state activation / deactivation MAC-CE structure according to an embodiment of the present disclosure is shown;

[0040] Figure 21 Operation of a terminal for transmitting or receiving demodulated signals in a wireless communication system according to embodiments of the present disclosure is illustrated;

[0041] Figure 22 Operation of a base station for transmitting or receiving demodulated signals in a wireless communication system according to embodiments of the present disclosure is illustrated;

[0042] Figure 23 The structure of a UE in a wireless communication system according to an embodiment of the present disclosure is shown; and

[0043] Figure 24 The structure of a base station in a wireless communication system according to an embodiment of the present disclosure is shown.

[0044] Throughout the accompanying drawings, it should be noted that the same reference numerals are used to depict the same or similar elements, features, and structures. Detailed Implementation

[0045] The following description with reference to the accompanying drawings is intended to aid in a full understanding of the various embodiments of this disclosure as defined by the claims and their equivalents. It includes various specific details to aid understanding, but these are considered exemplary only. Therefore, those skilled in the art will recognize that various changes and modifications can be made to the various embodiments described herein without departing from the scope and spirit of this disclosure. Additionally, for clarity and brevity, descriptions of well-known functions and structures may be omitted.

[0046] The terms and words used in the following description and claims are not limited to their literal meaning, but are used by the inventors only to enable a clear and consistent understanding of this disclosure. Therefore, it should be apparent to those skilled in the art that the following description of various embodiments of this disclosure is for illustrative purposes only and is not intended to limit the scope of this disclosure as defined by the appended claims and their equivalents.

[0047] It should be understood that, unless the context clearly specifies otherwise, the singular forms “a,” “an,” and “the” include plural indicators. Thus, for example, a reference to “component surface” includes a reference to one or more such surfaces.

[0048] For the same reason, some elements may be exaggerated, omitted, or shown schematically in the accompanying drawings. Furthermore, the size of each element does not perfectly reflect its actual size. The same reference numerals are used for identical or equivalent elements across the various drawings.

[0049] The advantages and features of this disclosure, as well as methods of implementing them, will become clear from the embodiments described in detail below with reference to the accompanying drawings. However, this disclosure is not limited to the embodiments set forth below, but can be implemented in various different forms. The following embodiments are provided only to fully disclose this disclosure and inform those skilled in the art of its scope, and this disclosure is limited only by the scope of the appended claims. Throughout the specification, the same or similar reference numerals indicate the same or similar elements. Furthermore, in describing this disclosure, detailed descriptions of known functions or configurations incorporated herein are omitted where it is determined that the description might unnecessarily obscure the subject matter of the disclosure. The terminology described below is defined in consideration of the functions in this disclosure and may vary depending on the user, the user's intention, or custom. Therefore, the definition of the terminology should be based on the entire contents of the specification.

[0050] In the following description, a base station is an entity that allocates resources to a terminal and can be at least one of a gNode B, eNode B, Node B, base station (BS), radio access unit, base station controller, and a node on a network. A terminal can include a user equipment (UE), mobile station (MS), cellular phone, smartphone, computer, or multimedia system capable of performing communication functions. In this disclosure, "downlink (DL)" can refer to a radio link through which a base station transmits signals to a terminal, and "uplink (UL)" can refer to a radio link through which a terminal transmits signals to a base station. Furthermore, in the following description, Long Term Evolution (LTE) or LTE-A Advanced (LTE-A) systems may be described by way of example, but embodiments of this disclosure can also be applied to other communication systems with similar technical backgrounds or channel types. Examples of such communication systems may include fifth-generation mobile communication technologies (5G, New Radio, and NR) developed in addition to LTE-A, and in the following description, "5G" can be a concept encompassing existing LTE, LTE-A, and other similar services. Additionally, based on the determination of those skilled in the art, this disclosure can also be applied to other communication systems with some modifications without significantly departing from the scope of this disclosure.

[0051] In this document, it should be understood that each block of a flowchart illustration, and combinations of blocks in a flowchart illustration, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in one or more flowchart blocks. These computer program instructions can also be stored in a computer-usable or computer-readable storage medium that can instruct the computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-usable or computer-readable storage medium produce an article of writing comprising instruction means for implementing the functions specified in one or more flowchart blocks. The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus, thereby producing a computer-implemented process, such that the instructions, which execute on the computer or other programmable apparatus, provide steps for implementing the functions specified in the flowchart blocks.

[0052] Furthermore, each box in the flowchart can represent a module, segment, or section of code, which includes one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions mentioned in the boxes may occur out of order. For example, depending on the functions involved, two boxes shown consecutively may actually execute substantially simultaneously, or these boxes may sometimes execute in reverse order.

[0053] As used in embodiments of this disclosure, the term "unit" refers to a software element or hardware element, such as a field-programmable gate array (FPGA) or application-specific integrated circuit (ASIC), and a "unit" can perform certain functions. However, "unit" is not always limited to software or hardware. A "unit" can be configured to be stored in addressable storage media or to run one or more processors. Thus, a "unit" includes, for example, software elements, object-oriented software elements, class elements or task elements, processes, functions, attributes, procedures, subroutines, program code segments, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and parameters. Elements and functions provided by a "unit" can be combined into a smaller number of elements or "units," or divided into a larger number of elements or "units." Furthermore, elements and "units" can be implemented as one or more central processing units (CPUs) within a playback device or secure multimedia card. Additionally, a "unit" in various embodiments of this disclosure can include one or more processors.

[0054] Wireless communication systems are evolving towards broadband wireless communication systems that utilize communication standards such as High-Speed ​​Packet Access (HSPA) of the 3rd Generation Partnership Project (3GPP), LTE (Long Term Evolution or Evolved Universal Terrestrial Radio Access (E-UTRA)), LTE-A Advanced, LTE-Pro, High-Rate Packet Data (HRPD) of 3GPP2, Ultra Mobile Broadband (UMB), IEEE 802.16e, and typical voice-based services to provide high-speed and high-quality packet data services.

[0055] As a typical example of a broadband wireless communication system, the LTE system employs Orthogonal Frequency Division Multiplexing (OFDM) in the downlink (DL) and Single-Carrier Frequency Division Multiple Access (SC-FDMA) in the uplink (UL). The uplink refers to the radio link through which a User Equipment (UE) or Mobile Station (MS) transmits data or control signals to a Base Station (BS) or eNodeB, and the downlink refers to the radio link through which the Base Station transmits data or control signals to the UE. These multiple access schemes separate the data or control information of each user by allocating and operating time-frequency resources for transmitting data or control information to each user, thus avoiding overlap and establishing orthogonality.

[0056] As a post-LTE communication system, 5G communication systems must freely reflect the various requirements of users, service providers, and others, and therefore must support services that meet diverse needs. Services considered in 5G communication systems include enhanced mobile broadband (eMBB) communication, massive machine-type communication (mMTC), and ultra-reliable low-latency communication (URLLC), among others.

[0057] eMBB aims to provide higher data rates than those supported by existing LTE, LTE-A, or LTE-Pro systems. For example, in 5G communication systems, eMBB must provide a peak data rate of 20 Gbps in the downlink and 10 Gbps in the uplink for a single base station. Furthermore, 5G communication systems must provide increased user-aware data rates and maximum data rates to the UE. To meet these requirements, improved transmit / receive technologies, including further enhanced multiple-input multiple-output (MIMO) transmission techniques, are needed. Moreover, the data rates required by 5G communication systems can be achieved using frequency bandwidths greater than 20 MHz in the 3 to 6 GHz band or 6 GHz or higher, rather than using up to 20 MHz of transmission bandwidth in the 2 GHz band used in LTE.

[0058] Furthermore, mMTC support for application services such as the Internet of Things (IoT) in 5G communication systems is being considered. To effectively deliver IoT, mMTC has requirements such as supporting a large number of UEs within a cell, enhancing UE coverage, improving battery life, and reducing UE costs. Since IoT provides communication capabilities while being supplied to various sensors and devices, it must support a large number of UEs within a cell (e.g., 1,000,000 UEs / km). 2 Additionally, UEs supporting mMTC may require wider coverage than other services offered by 5G communication systems because the UE may be located in shadow areas, such as the basement of a building, which are not covered by the cell due to the nature of the service. UEs supporting mMTC must be configured to be inexpensive and may require very long battery life, such as 10 to 15 years, because it is difficult to frequently replace the UE's battery.

[0059] Finally, URLLC is a mission-critical wireless communication service based on cellular networks. For example, URLLC can be used for services such as remote control of robots or machines, industrial automation, unmanned aerial vehicles, remote healthcare, and emergency alerts. Therefore, URLLC must provide communication with ultra-low latency and ultra-high reliability. For example, services supporting URLLC must meet an air interface latency of less than 0.5 ms and also require 10 -5 Or even lower packet error rates. Therefore, for services supporting URLLC, 5G systems must provide shorter transmission time intervals (TTIs) than other services, and may also require designs that allocate significant resources in the frequency band to ensure the reliability of the communication link.

[0060] The three services in 5G—eMBB, URLLC, and mMTC—can be multiplexed and transmitted within a single system. In this case, different transmit / receive technologies and parameters can be used across the services to meet their varying requirements. Of course, 5G is not limited to these three services.

[0061] NR Time and Frequency Resources

[0062] The frame structure of a 5G system will be described in more detail below with reference to the accompanying drawings.

[0063] It should be understood that the boxes in each flowchart and the combination of flowcharts can be executed by one or more computer programs including instructions. The entirety of one or more computer programs can be stored in a single memory device, or one or more computer programs can be divided into different parts stored in multiple different memory devices.

[0064] Any function or operation described herein may be processed by a processor or a combination of processors. A processor or a combination of processors is circuitry that performs processing and includes, for example, an application processor (AP, e.g., a central processing unit (CPU)), a communication processor (CP, e.g., a modem), a graphics processing unit (GPU), a neural processing unit (NPU) (e.g., an artificial intelligence (AI) chip), a Wi-Fi chip, and Bluetooth. ® Circuits for chips such as GPS chips, NFC chips, connectivity chips, sensor controllers, touch controllers, fingerprint sensor controllers, display driver integrated circuits (ICs), audio codec (CODEC) chips, universal serial bus (USB) controllers, camera controllers, image processing ICs, microprocessor units (MPUs), system-on-a-chip (SoCs), and ICs.

[0065] Figure 1 The basic structure of the time-frequency domain in a 5G system according to an embodiment of the present disclosure is shown. The time-frequency domain is a radio resource domain used for transmitting data or control channels.

[0066] refer to Figure 1 The horizontal axis represents the time domain, and the vertical axis represents the frequency domain. The basic unit of a resource in the time-frequency domain is a resource element (RE) 101, which can be defined as an orthogonal frequency division multiplexing (OFDM) symbol 102 on the time axis and a subcarrier 103 on the frequency axis. In the frequency domain, One (e.g., 12) consecutive REs can constitute a resource block (RB) 104. In the time domain, a subframe 110 can include multiple OFDM symbols 102. For example, the length of a subframe can be 1 ms.

[0067] Figure 2 The structure of frames, subframes, and time slots in a wireless communication system according to embodiments of the present disclosure is shown.

[0068] Figure 2 An example of the structure of frame 200, subframe 201, and time slot 202 is shown. A frame 200 can be defined as 10 ms. A subframe 201 can be defined as 1 ms, and therefore a frame 200 can include a total of ten subframes 201. A time slot 202 or 203 can be defined as 14 OFDM symbols (i.e., the number of symbols per time slot). =14). A subframe 201 may include one or more time slots 202 and 203, and the number of time slots 202 and 203 in each subframe 201 may vary depending on the configuration value μ of the subcarrier spacing 204 or 205. Figure 2The examples illustrate the cases where the subcarrier spacing configuration value is μ=0 (204) and μ=1 (205). In the case of μ=0 (204), a subframe 201 may include one time slot 202, and in the case of μ=1 (205), a subframe 201 may include two time slots 203. That is, the number of time slots in each subframe... This can vary depending on the subcarrier spacing configuration value μ, and each The number of time slots in a frame can vary accordingly. And... and The value μ can be defined based on the configuration of each subcarrier spacing, as shown in Table 1 below.

[0069] Table 1

[0070]

[0071] Bandwidth Component (BWP)

[0072] Next, the bandwidth portion (BWP) configuration in a 5G communication system will be described in detail with reference to the accompanying drawings.

[0073] Figure 3 An example of bandwidth configuration in a wireless communication system according to an embodiment of the present disclosure is shown.

[0074] Figure 3 An example is shown where the UE bandwidth 300 is configured to include two bandwidth portions, namely, bandwidth portion #1 (BWP#1) 301 and bandwidth portion #2 (BWP#2) 302. The base station can configure one or more bandwidth portions for the UE, and the following information can be configured for each bandwidth portion as given below.

[0075] Table 2

[0076]

[0077] Obviously, the above examples are not limiting, and various parameters related to the bandwidth portion can be configured for the UE in addition to the configuration information described above. The base station can transmit the configuration information to the UE via upper-layer signaling (e.g., Radio Resource Control (RRC) signaling). At least one of the configured bandwidth portions can be activated. Whether the configured bandwidth portion is activated can be transmitted from the base station to the UE semi-statically via RRC signaling or dynamically via downlink control information (DCI).

[0078] According to an embodiment, prior to Radio Resource Control (RRC) connection, the Initial Bandwidth Part (BWP) for initial access can be configured by the base station for the UE via the Master Information Block (MIB). More specifically, the UE can receive configuration information about the Control Resource Set (CORESET) and search space via the MIB during the initial access step. This configuration information can be used to send a PDCCH for receiving system information required for initial access (which may correspond to Residual System Information (RMSI) or System Information Block 1 (SIB1)). Each of the Control Resource Set and search space configured via the MIB can be considered as ID 0. The base station can notify the UE of configuration information about Control Resource Area #0 via the MIB, such as frequency allocation information, time allocation information, and values. Additionally, the base station can notify the UE of configuration information about the monitoring period and timing of Control Resource Set #0 via the MIB, i.e., configuration information about search space #0. The UE can consider the frequency domain configured by Control Resource Set #0 obtained from the MIB as the Initial Bandwidth Part for initial access. The ID of the Initial Bandwidth Part can be considered as 0.

[0079] The bandwidth-related configurations supported by 5G can be used for various purposes.

[0080] According to some embodiments, if the bandwidth supported by the UE is less than the system bandwidth, this can be supported through bandwidth portion configuration. For example, the base station can configure the frequency position of the bandwidth portion for the UE (configuration information 2), so that the UE can send / receive data at a specific frequency position within the system bandwidth.

[0081] Furthermore, according to the embodiments, in order to support different parameter sets, the base station can configure multiple bandwidth portions for the UE. For example, to support the UE to transmit / receive data using a 15kHz subcarrier spacing and a 30kHz subcarrier spacing, the two bandwidth portions can be configured with subcarrier spacings of 15kHz and 30kHz, respectively. Different bandwidth portions can withstand frequency division multiplexing (FDM), and if data needs to be transmitted / received at a specific subcarrier spacing, the bandwidth portion configured for the corresponding subcarrier spacing can be activated.

[0082] Additionally, according to embodiments, to reduce the power consumption of the UE, the base station can configure bandwidth portions with different bandwidth sizes for the UE. For example, if the UE supports a fairly large bandwidth, such as 100MHz, and always transmits / receives data at the corresponding bandwidth, a considerable amount of power consumption may occur. In particular, from a power consumption perspective, unnecessarily monitoring a downlink control channel with a large bandwidth of 100MHz when there is no service can be quite inefficient. To reduce the power consumption of the UE, the base station can configure a relatively small bandwidth portion for the UE (e.g., a 20MHz bandwidth portion). The UE can perform monitoring operations in the 20MHz bandwidth portion when there is no service, and if data has been transmitted, it can transmit / receive data using the 100MHz bandwidth portion as instructed by the base station.

[0083] By combining the bandwidth configuration method, the UE can receive configuration information about the initial bandwidth portion via the MIB during the initial access step before RRC connection. More specifically, the UE can have a control resource set (CORESET) configured for the downlink control channel, which can be used to transmit downlink control information (DCI) for scheduling system information blocks (SIBs) from the physical broadcast channel (PBCH). The bandwidth of the control resource set configured by the MIB can be considered as the initial bandwidth portion, and the UE can receive the physical downlink shared channel (PDSCH) through which the SIBs are transmitted via the configured initial bandwidth portion. The initial bandwidth portion can be used not only for receiving SIBs but also for other system information (OSI), paging, random access, etc.

[0084] Bandwidth Part (BWP) Change

[0085] If a UE has one or more bandwidth portions configured for it, the base station can indicate to the UE to change (or switch or transform) the bandwidth portion by using the bandwidth portion indicator field within the DCI. As an example, if the UE's currently active bandwidth portion is... Figure 3 If the bandwidth portion #1 301 is in the DCI, the base station can use the bandwidth portion indicator in the DCI to indicate the bandwidth portion #2 302, and the UE can change the bandwidth portion to the bandwidth portion #2 302 indicated by the bandwidth portion indicator in the received DCI.

[0086] As mentioned above, bandwidth portion changes based on DCI can be indicated by the DCI used to schedule PDSCH or PUSCH. Therefore, upon receiving a bandwidth portion change request, the UE needs to be able to receive or transmit PDSCH or PUSCH scheduled by the corresponding DCI without any problems within the changed bandwidth portion. To this end, the standard specifies the required delay time (T) during the bandwidth portion change.BWP The requirements of ) can be defined, for example, as shown below.

[0087] Table 3

[0088]

[0089] According to various embodiments of this disclosure, depending on the capabilities of the UE, the requirement for bandwidth portion change delay time can support either Type 1 or Type 2. The UE can report the supported bandwidth portion change delay time type to the base station.

[0090] If the UE has already received the DCI including the bandwidth partial change indicator in time slot n, then according to the above requirements regarding the bandwidth partial change delay time, the UE can proceed no later than time slot n+T. BWP The change to the new bandwidth portion indicated by the bandwidth portion change indicator is completed at the specified time point, and data channels scheduled by the corresponding DCI can be transmitted / received in the newly changed bandwidth portion. According to an embodiment, if the base station wants to schedule data channels using the new bandwidth portion, the base station can change the delay time (T) based on the UE's bandwidth portion. BWP This is used to determine the temporal resource allocation for the data channel. In other words, when scheduling a data channel using a new bandwidth portion, combined with the method used to determine the temporal resource allocation for the data channel, the base station can schedule the corresponding data channel after the bandwidth portion change delay time. Therefore, the UE can expect the DCI indicating the bandwidth portion change to indicate a delay time less than the bandwidth portion change delay time (T). BWP The time slot offset (K0 or K2) value.

[0091] If the UE has already received a DCI indicating a partial bandwidth change (e.g., DCI format 1_1 or 0_1), the UE may refrain from transmitting or receiving for the time interval from the third symbol of the slot used to receive the PDCCH including the corresponding DCI to the start of the slot indicated by the slot offset (K0 or K2) value indicated by the time domain resource allocation indicator field in the corresponding DCI. For example, if the UE has already received a DCI indicating a partial bandwidth change in slot n, and if the slot offset value indicated by the corresponding DCI is K, the UE may refrain from transmitting or receiving from the third symbol of slot n to the symbols preceding slot n+K (e.g., the last symbol of slot n+K-1).

[0092] SS / PBCH block

[0093] Next, the synchronization signal (SS) / PBCH block in 5G will be described.

[0094] The SS / PBCH block can refer to a physical layer channel block that includes the primary synchronization signal (PSS), secondary synchronization signal (SSS), and PBCH. Details are as follows.

[0095] -PSS: A signal that serves as a reference for downlink time / frequency synchronization and provides partial information about the cell ID.

[0096] -SSS: Serves as a reference for downlink time / frequency synchronization and provides residual cell ID information not provided by PSS. Additionally, SSS can be used as a reference signal for PBCH demodulation.

[0097] -PBCH: Provides the MIB, which is mandatory system information required by the UE to transmit / receive data and control channels. Mandatory system information may include search space-related control information indicating radio resource mapping information for control channels, scheduling control information regarding separate data channels used for transmitting system information, etc.

[0098] -SS / PBCH Blocks: SS / PBCH blocks consist of a combination of PSS, SSS, and PBCH. One or more SS / PBCH blocks can be sent within a 5 ms time period, and each sent SS / PBCH block can be distinguished by an index.

[0099] According to various embodiments of this disclosure, the UE can detect the PSS and SSS, and can decode the PBCH during the initial access procedure. The UE can obtain the MIB from the PBCH, and this can be used to configure the control resource set (CORESET) #0 (which may correspond to, for example, a control resource set with control resource set index 0). The UE can monitor the control resource set #0 by assuming that the demodulation reference signal (DMRS) transmitted in the selected SS / PBCH block and that the control resource set #0 is quasi-co-located (QCL). The UE can receive system information containing downlink control information transmitted in the control resource set #0. The UE can obtain configuration information related to the random access channel (RACH) required for initial access from the received system information. The UE can send a physical RACH (PRACH) to the base station considering the selected SS / PBCH index, and the base station can obtain information about the SS / PBCH block index selected by the UE upon receiving the PRACH. The base station can know which block the UE has selected from each SS / PBCH block, and the fact that the associated control resource set #0 is being monitored.

[0100] DRX

[0101] Figure 6 An example of discontinuous reception (DRX) operation in a wireless communication system according to an embodiment of the present disclosure is shown.

[0102] DRX refers to the operation of a UE currently using the service to discontinuously receive data in an RRC connection state where a radio link is configured between the base station and the UE. If DRX is applied, the UE can turn on the receiver at specific times to monitor the control channel, and turn it off if no data is received within a predetermined time period, thereby reducing the power consumption of the UE. DRX operation can be controlled by MAC layer devices based on various parameters and timers.

[0103] refer to Figure 6 Activity time 605 refers to the time during which the UE wakes up and monitors the PDCCH in each DRX cycle. Activity time 605 can be defined as follows.

[0104] -drx-onDurationTimer or drx-InactivityTimer or drx-RetransmissionTimerDL or drx-RetransmissionTimerUL or ra-ContentionResolutionTimer is running; or

[0105] - The scheduling request was sent on the PUCCH and is pending; or

[0106] - After successfully receiving a random access response for a contention-based random access preamble that was not selected by the MAC entity, and before receiving a new transmission of C-RNTI indicating addressing to the MAC entity, a PDCCH has not yet been received.

[0107] drx-onDurationTimer, drx-InactivityTimer, drx-RetransmissionTimerDL, drx-RetransmissionTimerUL, ra-ContentionResolutionTimer, etc. are timers with values ​​configured by the base station and have the function of enabling the UE to monitor the PDCCH when predetermined conditions are met.

[0108] `drx-onDurationTimer` 615 is a parameter used to configure the minimum wake-up time for the UE during the DRX cycle. `drx-InactivityTimer` 620 is a parameter used to configure the additional wake-up time for the UE upon receiving a PDCCH (630) indicating a new uplink or downlink transmission. `drx-RetransmissionTimerDL` is a parameter used to configure the maximum wake-up time for the UE to receive downlink retransmissions during downlink HARQ. `drx-RetransmissionTimerUL` is a parameter used to configure the maximum wake-up time for the UE to receive uplink retransmission grants during uplink HARQ. `drx-onDurationTimer`, `drx-InactivityTimer`, `drx-RetransmissionTimerDL`, and `drx-RetransmissionTimerUL` can be configured as, for example, time, the number of subframes, the number of time slots, etc. `ra-ContentionResolutionTimer` is a parameter used to monitor the PDCCH during random access.

[0109] The inactive time 610 refers to the time during which the UE is configured not to monitor the PDCCH or to receive the PDCCH during DRX operation, and the inactive time 610 can be obtained by subtracting the active time 605 from the total time of performing the DRX operation. If the UE does not monitor the PDCCH during the active time 605, the UE can enter a sleep or inactive state, thereby reducing power consumption.

[0110] The DRX cycle refers to the period during which the UE wakes up and monitors the PDCCH. In other words, the DRX cycle is the time interval between when the UE monitors the PDCCH and when it monitors the next PDCCH, or the cycle of the duration of the on-time event. There are two types of DRX cycles: short DRX cycles and long DRX cycles. Short DRX cycles can be optionally applied.

[0111] The long DRX period 625 is the longer period between two DRX periods configured for the UE. When operating with long DRX, the UE restarts drx-onDurationTimer 615 at a point in time where the long DRX period 625 has elapsed since the start point (e.g., the start symbol) of drx-onDurationTimer 615. If operating with long DRX period 625, the UE can start drx-onDurationTimer 615 in a slot following the drx-SlotOffset in a subframe that satisfies Equation 1 below. Here, drx-SlotOffset refers to the delay before drx-onDurationTimer 615 starts. drx-SlotOffset can be configured as, for example, time, the number of slots, etc.

[0112] [(SFN x 10) + subframe number] modulus (drx - LongCycle) = drx - StartOffset

[0113] Equation 1

[0114] The `drx-LongCycleStartOffset` parameter defines a long DRX cycle of 625, and the `drx-StartOffset` parameter defines the subframe that begins the long DRX cycle of 625. `drx-LongCycleStartOffset` can be configured with parameters such as time, the number of subframes, and the number of time slots.

[0115] [PDCCH: About DCI]

[0116] Next, we will describe downlink control information (DCI) in a 5G system in detail.

[0117] In 5G systems, scheduling information regarding uplink data (or Physical Uplink Shared Channel (PUSCH)) or downlink data (or Physical Downlink Shared Channel (PDSCH)) is included in the DCI and transmitted from the base station to the UE via the DCI. The UE can monitor the backoff DCI format and the non-backoff DCI format regarding the PUSCH or PDSCH. The backoff DCI format may include predefined fixed fields between the base station and the UE, while the non-backoff DCI format may include configurable fields.

[0118] The DCI (Distributed Communication Interface) can undergo channel coding and modulation processes, and then be transmitted via the Physical Downlink Control Channel (PDCCH) after these processes. Cyclic Redundancy Check (CRC) can be appended to the payload of the DCI message, and the CRC can be scrambled by a Radio Network Temporary Identifier (RNTI) corresponding to the UE's identifier. Different RNTIs can be used depending on the purpose of the DCI message, such as UE-specific data transmission, power control commands, or random access responses. That is, the RNTI may not be explicitly sent, but can be sent concurrently with the CRC calculation process. Upon receiving a DCI message transmitted via the PDCCH, the UE can identify the CRC using the assigned RNTI, and if the CRC identification result is correct, the UE knows that the corresponding message has been sent to the UE.

[0119] For example, the DCI used for scheduling PDSCH about System Information (SI) can be scrambled by SI-RNTI. The DCI used for scheduling PDSCH about Random Access Response (RAR) messages can be scrambled by RA-RNTI. The DCI used for scheduling PDSCH about paging messages can be scrambled by P-RNTI. The DCI used for notifying Slot Format Indicator (SFI) can be scrambled by SFI-RNTI. The DCI used for notifying Transmit Power Control (TPC) can be scrambled by TPC-RNTI. The DCI used for scheduling UE-specific PDSCH or PUSCH can be scrambled by Cell RNTI (C-RNTI).

[0120] DCI format 0_0 can be used as a fallback DCI for scheduling PUSCH, and in this case, CRC can be scrambled by C-RNTI. DCI format 0_0 with CRC scrambling via C-RNTI may include, for example, the following information.

[0121] Table 4

[0122]

[0123] DCI format 0_1 ​​can be used as a non-back-off DCI for scheduling PUSCH, and in this case, CRC can be scrambled by C-RNTI. DCI format 0_1 ​​with CRC scrambling via C-RNTI may include, for example, the following information.

[0124] Table 5

[0125]

[0126]

[0127] DCI format 1_0 can be used as a fallback DCI for scheduling PDSCH, and in this case, CRC can be scrambled by C-RNTI. DCI format 1_0 with CRC scrambling via C-RNTI may include, for example, the following information.

[0128] Table 6

[0129]

[0130] DCI format 1_1 can be used as a non-back-off DCI for scheduling PDSCH, and in this case, CRC can be scrambled by C-RNTI. DCI format 1_1 with CRC scrambling via C-RNTI may include, for example, the following information.

[0131] Table 7

[0132]

[0133]

[0134] The downlink control channel in a 5G communication system will be described in more detail below with reference to the accompanying drawings.

[0135] Figure 4 An example of the configuration of the control resource set for the downlink control channel in a wireless communication system according to embodiments of the present disclosure is shown. More specifically, Figure 4 An example of a control resource set (CORESET) used to transmit downlink control channels in a 5G wireless communication system is illustrated.

[0136] Figure 4 An example is shown where the UE bandwidth portion 410 is configured along the frequency axis, and two control resource sets (control resource set #1 401 and control resource set #2 402) are configured along the time axis within a time slot 420. Control resource sets 401 and 402 can be configured along the frequency axis within a specific frequency resource 403 throughout the entire UE bandwidth portion 410. Control resource sets 401 and 402 can each be configured as one or more OFDM symbols along the time domain, and the number of OFDM symbols can be defined as the control resource set duration 404. Reference Figure 4 In the example shown, control resource set #1 401 is configured to have control resource set durations corresponding to two symbols, and control resource set #2 402 is configured to have control resource set durations corresponding to one symbol.

[0137] The control resource set in 5G described above can be configured by the base station for the UE via upper-layer signaling (e.g., system information, master information block (MIB), radio resource control (RRC) signaling). Configuring the control resource set for the UE means providing information such as the control resource set identifier, the frequency location of the control resource set, and the symbol duration of the control resource set. For example, this may include the following information.

[0138]

[0139] In Table 8, the tci-StatesPDCCH (Transmission Configuration Indication (TCI) status) configuration information may include information on one or more SS / PBCH block indices or Channel State Information Reference Signal (CSI-RS) indices, which are co-located (OCL) with the DMRS transmitted in the corresponding control resource set.

[0140] Figure 5A The structure of a downlink control channel in wireless communication according to an embodiment of the present disclosure is shown. More specifically, Figure 5A An example of the basic unit constituting the time and frequency resources of the downlink control channel available in a 5G system is shown.

[0141] refer to Figure 5A The basic unit constituting the time and frequency resources of the control channel can be called a resource element group (REG) 503, and REG 503 can be defined by an OFDM symbol 501 along the time axis and a physical resource block (PRB) 502 (i.e., 12 subcarriers) along the frequency axis. The base station can configure the downlink control channel allocation unit by cascading REG 503.

[0142] Assuming the basic unit of downlink control channel allocation in 5G is as follows: Figure 5A The control channel element 504 shown can be a single CCE 504 that may include multiple REG 503s. (For description...) Figure 5A The REG 503 shown, for example, may include 12 REs, and if a CCE 504 includes six REG 503s, then a CCE 504 may include 72 REs. Once configured, a downlink control resource set may include multiple CCE 504s, and a specific downlink control channel may be mapped to one or more CCE 504s and then transmitted according to the aggregation level (AL) in the control resource set. CCE 504s in the control resource set are distinguished by numbering, and the numbers of CCE 504s may be assigned according to a logical mapping scheme.

[0143] Figure 5AThe basic unit of the downlink control channel shown (i.e., REG 503) can include both the RE to which the DCI is mapped and the region to which the reference signal (DMRS 505) used for decoding it is mapped. Figure 5A In this configuration, three DRMS ​​505s can be transmitted within a single REG 503. Depending on the aggregation level (AL), the number of CCEs required to transmit the PDCCH can be 1, 2, 4, 8, or 16, and different numbers of CCEs can be used to achieve link adaptation of the downlink control channel. For example, in the case of AL=L, a downlink control channel can be transmitted using L CCEs. The UE needs to detect signals without information about the downlink control channel, and therefore a search space indicating the set of CCEs can be defined for blind decoding. The search space is the set of downlink control channel candidates that includes the CCEs the UE needs to attempt to decode at a given AL, and since 1, 2, 4, 8, or 16 CCEs can form a bundle at various ALs, the UE can have multiple search spaces. The search space set can be defined as the search space set for all configured aggregation levels.

[0144] The search space can be categorized into a shared search space and a UE-specific search space. A 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 used to transmit 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, a group of UEs or all UEs need to receive the PDCCH, and the common search space can therefore be defined as a predetermined set of CCEs. Scheduling allocation information for UE-specific PDSCHs or PUSCHs can be received by searching the UE-specific search space of the PDCCH. The UE-specific search space can be defined specifically by the UE based on various system parameters and the UE's identifier.

[0145] In 5G, the base station can configure parameters for the PDCCH search space for the UE via upper-layer signaling (e.g., SIB, MIB, or RRC signaling). For example, the base station can also provide the UE with configurations such as the number of PDCCH candidates for each aggregation level L, the monitoring period for the search space, the monitoring timing for each symbol within a time slot related to the search space, the search space type (common search space or UE-specific search space), the combination of RNTI and DCI formats monitored in the corresponding search space, and the control resource set index used to monitor the search space. For example, the following information may be included.

[0146] Table 9

[0147]

[0148]

[0149] Based on the configuration information, the base station can configure one or more search space sets for the UE. According to some embodiments, the base station can configure search space set 1 and search space set 2 for the UE, and can configure DCI format A scrambled by X-RNTI to be monitored in the common search space in search space set 1, and can configure DCI format B scrambled by Y-RNTI to be monitored in the UE-specific search space in search space set 2.

[0150] Depending on the configuration information, one or more search space sets may exist within the public search space or the UE-specific search space. For example, search space set #1 and search space set #2 can be configured as a public search space, and search space set #3 and search space set #4 can be configured as UE-specific search spaces.

[0151] The combinations of DCI format and RNTI given below can be monitored in the public search space. Obviously, the examples given below are not limiting.

[0152] DCI format 0_0 / 1_0 with CRC scrambled by C-RNTI, CS-RNTI, SP-CSI-RNTI, RA-RNTI, TC-RNTI, P-RNTI, and SI-RNTI.

[0153] DCI format 2_0 with CRC scrambled by SFI-RNTI

[0154] DCI format 2_1 with CRC scrambled by INT-RNTI

[0155] DCI format 2_2 with CRC scrambled by TPC-PUSCH-RNTI and TPC-PUCCH-RNTI

[0156] DCI format 2_3 with CRC scrambled by TPC-SRS-RNTI

[0157] The combinations of DCI formats and RNTI given below can be monitored within the UE-specific search space. Obviously, the embodiments given below are not limiting.

[0158] DCI format 0_0 / 1_0 with CRC scrambled by C-RNTI, CS-RNTI, and TC-RNTI

[0159] DCI format 1_0 / 1_1 with CRC scrambled by C-RNTI, CS-RNTI, and TC-RNTI

[0160] The enumerated RNTI can follow the definitions and usage given below.

[0161] Cell RNTI (C-RNTI): Used to schedule UE-specific PDSCH

[0162] Temporary Cell RNTI (TC-RNTI): Used to schedule UE-specific PDSCH

[0163] Configured Scheduling RNTI (CS-RNTI): Used to schedule UE-specific PDSCHs with semi-static configuration.

[0164] Random Access RNTI (RA-RNTI): Used to schedule PDSCH during the random access step.

[0165] Paging RNTI (P-RNTI): Used to schedule the PDSCH sent for paging.

[0166] System Information RNTI (SI-RNTI): Used to schedule the PDSCH in which system information is sent.

[0167] Interrupt RNTI (INT-RNTI): Used to indicate whether the PDSCH has been punctured.

[0168] Transmit power control for PUSCH RNTI (TPC-PUSCH-RNTI): Used to indicate power control commands regarding PUSCH.

[0169] Transmit power control for PUCCH RNTI (TPC-PUCCH-RNTI): Used to indicate power control commands regarding the PUCCH.

[0170] Transmit power control for SRS RNTI (TPC-SRS-RNTI): Used to indicate power control commands regarding the SRS.

[0171] The DCI formats listed above can follow the definitions given below.

[0172] Table 10

[0173]

[0174] In a 5G system, the search space of the aggregation level L associated with CORESET p and the search space set s can be represented by the following Equation 2.

[0175]

[0176] …Equation 2

[0177] - L: Aggregation Level

[0178] - Carrier index

[0179] - Control resource set p The total number of CCEs existing in

[0180] - Time slot index

[0181] - Number of PDCCH candidates under aggregation level L

[0182] - -=0, … , -1: PDCCH candidate index under aggregation level L

[0183] - = 0, …, -1

[0184] - , , , , ,

[0185] - UE identifier

[0186] In the context of public search spaces, The value can correspond to 0.

[0187] In the case of a specific search space for the UE The value can correspond to a value that is changed by the UE's identifier (C-RNTI or ID configured by the base station for the UE) and time index.

[0188] In 5G, multiple search space sets can be configured with different parameters (e.g., the parameters in Table 9), and the groups of search space sets monitored by the UE at each time point can be different accordingly. For example, if search space set #1 is configured according to time slot X, and search space set #2 is configured according to time slot Y, and if X and Y are different, the UE can monitor both search space set #1 and search space set #2 in a specific time slot, and can monitor only one of search space set #1 and search space set #2 in another specific time slot.

[0189] PDCCH: Span

[0190] Regarding the scenario where a UE has multiple PDCCH monitoring opportunities within a time slot, the UE can perform a UE capability report at each subcarrier interval, and the concept of a "span" can be used in this regard. A span refers to the consecutive symbols of the PDCCH configured to allow the UE to monitor within a time slot, with each PDCCH monitoring opportunity occurring within a span. A span can be represented as (X, Y), where X represents the minimum number of symbols that must separate the first symbols of two consecutive spans, and Y represents the number of consecutive symbols of the PDCCH that can be monitored within a span. The UE can monitor the PDCCH within a span corresponding to Y symbols starting from the first symbol of the span.

[0191] Figure 5B The present disclosure illustrates a scenario in a wireless communication system where, in terms of span, a UE may have multiple PDCCH monitoring opportunities within a time slot.

[0192] According to various embodiments of this disclosure, the possible spans are (X,Y) = (7,3), (4,3), and (2,2), and these three cases can be respectively determined by... Figure 5B The instructions (510), (520), and (530) are as follows. As an example, (510) describes the case where there are two spans described by (7,4) within a time slot. The interval between the first symbols of the two spans is described as X=7, the PDCCH monitoring timing can exist within a total of Y=3 symbols from the first symbol of each span, and search spaces 1 and 2 can each exist within Y=3 symbols. As another example, (520) describes a case where there are a total of three spans described by (4,3) within a time slot, and the second and third spans are separated by X'=5 symbols, which is greater than X=4. Similarly, (530) describes the case where there is a span described by (2,2) within a time slot.

[0193] PDCCH: UE Capability Report

[0194] The slot locations of the aforementioned public search space and UE-specific search space are indicated by the parameter "monitoringSymbolsWithinSlot" in Table 11-1, and the symbol positions within the slots are indicated as a bitmap by the parameter "monitoringSymbolsWithinSlot" in Table 9. Simultaneously, the UE can report the symbol positions within the slots of the search space that it can monitor to the base station through the following UE capabilities.

[0195] - UE Capability 1 (hereinafter referred to as FG 3-1). This UE capability can have the following meaning: If there is a monitoring opportunity (MO) regarding the Type 1 and Type 3 common search space or the UE-specific search space within a time slot, as shown in Table 11 below, then the UE can monitor the corresponding MO when it is located within the first three symbols of the time slot. This UE capability is a mandatory capability supported by all UEs supporting NR, and does not explicitly report to the base station whether UE Capability 1 is supported.

[0196] Table 11-1

[0197]

[0198]

[0199] - UE Capability 2 (hereinafter referred to as FG 3-2). This UE capability means that if a monitoring opportunity (MO) exists within a time slot regarding a common search space or a UE-specific search space, as shown in Table 11-2 below, the UE can monitor the corresponding MO, regardless of what the starting symbol position of the corresponding MO might be. This UE capability is optionally supported by the UE, and whether or not the UE capability is supported is explicitly reported to the base station.

[0200] Table 11-2

[0201]

[0202] - UE Capability 3 (hereinafter referred to as FG 3-5, 3-5a, or 3-5b). This UE capability has the following meaning: if multiple monitoring opportunities (MOs) exist within a time slot regarding a common search space or a UE-specific search space, as shown in Table 11-3 below, it indicates the pattern of MOs that the UE can monitor. The above pattern includes the interval X between the start symbols of different MOs, and the maximum symbol length Y of a MO. The combination of (X,Y) supported by the UE can be one or more of {(2,2), (4,3), (7,3)}. This UE capability is optionally supported by the UE, and whether the UE capability is supported and the above combination of (X,Y) is explicitly reported to the base station.

[0203] Table 11-3

[0204]

[0205]

[0206] The UE can report to the base station whether it supports capability 2 or capability 3 mentioned above, along with related parameters. Based on the UE's capability report, the base station can allocate time-domain resources to the common search space and the UE-specific search space. According to an embodiment, during resource allocation, the base station can ensure that the MO is not located in a position where the UE cannot monitor the MO.

[0207] PDCCH: BD / CCE Limitation

[0208] If multiple search space sets exist for the UE, the following conditions can be considered in conjunction with the methods used to determine the search space set to be monitored by the UE.

[0209] According to an embodiment, if the value of "monitoringCapabilityConfig-r16" (upper-layer signaling) for the UE has been configured as "r15monitoringcapability", then the UE defines, for each time slot, a maximum value for the number of PDCCH candidates that can be monitored and the number of CCEs that constitute the entire search space (as used herein, the entire search space refers to the entire set of CCEs corresponding to the union domain of multiple search space sets). According to an embodiment, if the value of "monitoringCapabilityConfig-r16" has been configured as "r16monitoringcapability", then the UE defines, for each span, a maximum value for the number of PDCCH candidates that can be monitored and the number of CCEs that constitute the entire search space (as used herein, the entire search space refers to the entire set of CCEs corresponding to the union domain of multiple search space sets).

[0210] Condition 1: The maximum number of PDCCH candidates is limited.

[0211] Based on the above upper-layer signaling configuration values, if the maximum number of PDCCH candidates Mμ that the UE can monitor is defined with reference to the time slots in a cell configured with a subcarrier spacing of 15.2 μ kHz, then the maximum number of PDCCH candidates Mμ that the UE can monitor can follow the table 12-1 given below. And if the maximum number of PDCCH candidates Mμ that the UE can monitor is defined with reference to the span, then the maximum number of PDCCH candidates Mμ that the UE can monitor can follow the table 12-2 given below.

[0212] Table 12-1

[0213]

[0214] Table 12-2

[0215]

[0216] Condition 2: The maximum number of CCEs is limited.

[0217] Based on the aforementioned upper-layer signaling configuration values, if the maximum number of CCEs Cμ constituting the entire search space is defined by referring to the time slots in a cell configured with a subcarrier spacing of 15.2 μ kHz (as used herein, the entire search space refers to the entire set of CCEs corresponding to the union domain of multiple search space sets), it can follow the table 12-3 given below, and if defined by referring to the span, it can follow the table 12-4 given below.

[0218] Table 12-3

[0219]

[0220] Table 12-4

[0221]

[0222] For ease of description, the situation where both conditions 1 and 2 are satisfied at a specific point in time can be defined as "condition A". Therefore, the description of not satisfying condition A can mean that at least one of conditions 1 and 2 is not satisfied.

[0223] PDCCH: Overbooking

[0224] Depending on the configuration of the base station's search space set, condition A may not be met at a specific time point. If condition A is not met at a specific time point, the UE can select and monitor only some of the search space sets configured to meet condition A at the corresponding time point, and the base station can send PDCCH to the selected search space set.

[0225] The method for selecting some search spaces from the set of search spaces of all configurations can follow the approach given below.

[0226] If condition A regarding PDCCH is not met at a specific time point (time slot), the UE (or base station) may, with priority over the search space set configured as the UE-specific search space set, select a search space set with a search space type configured as a common search space from the search space sets existing at the corresponding time point.

[0227] If all search space sets configured as public search spaces have already been selected (i.e., if condition A is satisfied even after all search spaces configured as public search spaces have been selected), the UE (or base station) can select a search space set configured as a UE-specific search space. If multiple search space sets are configured as UE-specific search spaces, the search space set with the lower search space set index can have a higher priority. Considering priority, a UE-specific search space set can be selected as long as condition A is satisfied.

[0228] QCL, TCI status

[0229] In wireless communication systems, one or more different antenna ports (which can be replaced by one or more channels, signals, and combinations thereof, but for convenience, will be referred to collectively as different antenna ports in the following description of this disclosure) can be associated with each other through quasi-co-location (QCL) configuration, as shown in Table 13 below. The TCI state is used to announce the QCL relationship between the PDCCH (or PDCCHDRMS) and another RS ​​or channel. The description of mutual QCL between reference antenna port A (reference RS#A) and another target antenna port B (target RS#B) implies that the UE is allowed to apply some or all of the large-scale channel parameters estimated in antenna port A to channel measurements in antenna port B. QCL needs to be associated with different parameters depending on the situation, such as 1) time tracking affected by average delay and delay spread, 2) frequency tracking affected by Doppler shift and Doppler spread, 3) radio resource management (RRM) affected by average gain, or 4) beam management (BM) affected by spatial parameters. Therefore, four types of QCL relationships are supported in NR, as shown in Table 13 below.

[0230] Table 13

[0231]

[0232] Spatial RX parameters can refer to some or all of a variety of parameters as a whole, such as angle of arrival (AoA), power angular spectrum (PAS) of AoA, angle of departure (AoD), PAS of AoD, transmit / receive channel correlation, transmit / receive beamforming, and spatial channel correlation.

[0233] QCL relationships can be configured for the UE using the RRC parameters TCI-state and QCL-info, as shown in Table 14 below. Referring to Table 14, the base station can configure one or more TCI states for the UE, thereby informing the UE of up to two QCL relationships (qcl-Type1, qcl-Type2) regarding the ID of the reference TCI state (i.e., the target RS). Each QCL information (QCL-Info) for each TCI state can include the serving cell index and BWP index of the reference RS indicated by the corresponding QCL information, the type and ID of the reference BS, and the QCL type, as shown in Table 13 above.

[0234] Table 14

[0235]

[0236] Figure 7 An example of base station beam allocation configured according to TCI state in a wireless communication system according to an embodiment of the present disclosure is shown. Reference Figure 7 The base station can transmit information about N different beams to the UE through N different TCI states. For example, in... Figure 7 In the case of N=3, the base station can configure qcl-Type2 parameters in QCL type D, which are included in the three TCI states 700, 705 and 710, and associate them with CSI-RS or SSB corresponding to different beams, thereby notifying the antenna ports of different TCI states 700, 705 and 710 that they are associated with different spatial Rx parameters (i.e. different beams).

[0237] Tables 15-1 to 15-5 below list the valid TCI state configurations based on the target antenna port type.

[0238] Table 15-1 lists the valid TCI state configurations when the target antenna port is a CSI-RS (TRS) used for tracking. A TRS refers to an NZPCSI-RS within the CSI-RS that has not been configured with repeat parameters and whose trs-Info is configured as "true". In Table 15-1, configuration 3 can be used for aperiodic TRSs.

[0239] Table 15-1 Effective TCI State Configuration When the Target Antenna Port is a CSI-RS (TRS) for Tracking

[0240]

[0241] Table 15-2 lists the valid TCI state configurations when the target antenna port is a CSI-RS for CSI. A CSI-RS for CSI can refer to an NZP CSI-RS for which no parameter indicating repetition (e.g., repetition parameter) is configured in the CSI-RS and whose trs-Info is not configured as "true".

[0242] Table 15-2 Effective TCI State Configuration when the target antenna port is a CSI-RS for CSI

[0243]

[0244] Table 15-3 lists the valid TCI status configurations when the target antenna port is a CSI-RS for beam management (BM) (which has the same meaning as a CSI-RS for L1RSRP reporting). A CSI-RS for BM refers to an NZPCSI-RS that has repeating parameters in the CRI-RS configured with values ​​of "on" or "off" and whose trs-Info is not configured as "true".

[0245] Table 15-3 Valid TCI State Configurations When the Target Antenna Port is Used for BM's CSI-RS (for L1 RSRP Reporting)

[0246]

[0247] Table 15-4 lists the valid TCI state configurations when the target antenna port is PDCCH DMRS.

[0248] Table 15-4 Effective TCI State Configuration when the Target Antenna Port is PDCCH DMRS

[0249]

[0250] Table 15-5 lists the valid TCI state configurations when the target antenna port is PDSCH DMRS.

[0251] Table 15-5 Effective TCI State Configuration when the Target Antenna Port is PDSCH DMRS

[0252]

[0253] Based on the representative QCL configuration methods in Tables 15-1 to 15-5 above, the target antenna port and reference antenna port are configured and operated for each step, such as "SSB" -> "TRS" -> "CSI-RS of CSI, or CSI-RS of BM, or PDCCH DMRS, or PDSCH DMRS". Therefore, the UE's reception operation can be aided by associating statistical characteristics that can be measured from SSB and TRS with the corresponding antenna ports.

[0254] PDCCH: Regarding TCI Status

[0255] The specific TCI state combinations applicable to the PDCCH DMRS antenna port can be given in Table 16 below. The fourth row in Table 16 corresponds to the combination assumed by the UE before RRC configuration and which cannot be configured after RRC.

[0256] Table 16

[0257]

[0258] Figure 8 An example of a method for assigning TCI state of PDCCH in a wireless communication system according to an embodiment of the present disclosure is shown.

[0259] In NR, dynamic allocation of PDCCH beams is supported, such as... Figure 8 The layered signaling method is shown. (See reference.) Figure 8 The base station can configure N TCI states 805, 810, 815, ..., 820 for the UE via RRC signaling 800, and can configure some of them as the TCI state for CORESET (825). The base station can then indicate one of the TCI states 830, 835, and 840 for CORESET (845) to the UE via MAC CE signaling. The UE can then receive the PDCCH based on the beam information included in the TCI state indicated by the MAC CE signaling.

[0260] Figure 9 The TCI indication MACCE signaling structure for PDCCH DMRS in a wireless communication system according to an embodiment of the present disclosure is shown. More specifically, Figure 9 The TCI indication MAC CE signaling structure for PDCCH DMRS is shown.

[0261] refer to Figure 9The TCI indication MAC CE signaling for PDCCH DMRS can be configured by 2 bytes (16 bits) 900 and 905, and includes a 5-bit serving cell ID 915, a 4-bit CORESET ID 920 and a 7-bit TCI status ID 925.

[0262] Figure 10 An example of beam configuration regarding the control resource set and search space in a wireless communication system according to embodiments of the present disclosure is shown. More specifically, Figure 10 An example of beam configuration based on the control resource set (CORESET) and search space described above is shown. (Reference) Figure 10 The base station can indicate one of the TCI state lists (1005) included in the CORESET#1 (1000) configuration via MAC CE signaling. Before indicating different TCI states for the corresponding CORESET via different MAC CE signaling, the UE can assume that the same QCL information (beam #1) 1005 is applied to all one or more search spaces 1010, 1015, and 1020 connected to the CORESET. The above PDCCH beam allocation method may have the following problems: it is difficult to indicate beam changes faster than the MAC CE signaling delay, and the same beam is unilaterally applied to each CORESET regardless of search space characteristics, making flexible PDCCH beam operation difficult. The following embodiments of this disclosure provide a more flexible PDCCH beam configuration and operation method. Although several different examples will be provided for ease of description of embodiments of this disclosure, they are not mutually exclusive and can be appropriately combined and applied for each situation.

[0263] The base station can configure one or more TCI states for a UE for a specific control resource set, and can activate one of the configured TCI states via a MAC CE activation command. For example, if {TCI state #0, TCI state #1, TCI state #2} is configured as the TCI state of control resource set #1, the base station can send an activation command to the UE via MAC CE, causing TCI state #0 to be assumed to be the TCI state of control resource set #1. Based on the activation command for the TCI state received via MAC CE, the UE can correctly receive the DMRS of the corresponding CORESET based on the QCL information of the activated TCI state.

[0264] Regarding the control resource set with configured index 0 (control resource set #0), if the UE fails to receive a MAC CE activation command regarding the TCI state of control resource set #0, the UE may assume that the DMRS sent in control resource set #0 has been associated with the SS / PBCH block (SSB) QCL identified during the initial access process or during a contention-free random access process not triggered by a PDCCH command.

[0265] Regarding a control resource set (CORESET#X) with a configuration index value other than 0, if the UE does not have a TCI state configured for CORESET#X, or if the UE has one or more TCI states configured for it but has failed to receive a MAC CE activation command to activate one of them, the UE may assume that the DMRS sent in CORESET#X has been associated with the SS / PBCH block QCL identified during the initial access procedure.

[0266] PDCCH: Regarding QCL priority ordering rules

[0267] The following sections will describe in detail the operations used to determine the QCL priority for the PDCCH.

[0268] If, during a specific PDCCH monitoring session, carrier aggregation is performed within a single cell or frequency band, and multiple control resource sets existing within the active bandwidth portion of one or more cells overlap temporally and possess the same or different QCL-TypeD characteristics, the UE can select a specific control resource set based on the QCL priority determination operation and can monitor control resource sets with the same QCL-TypeD characteristics as the corresponding control resource set. In other words, if multiple control resource sets overlap temporally, only one QCL-TypeD characteristic can be received. QCL priority can be determined using the following criteria.

[0269] Standard 1. A set of control resources connected to the lowest index common search space within a cell that corresponds to the lowest index in a cell that includes a common search space.

[0270] Standard 2. A set of control resources connected to the UE-specific search space with the lowest index within the cell corresponding to the lowest index in a cell that includes the UE-specific search space.

[0271] As stated above, if one of the criteria is not met, the next criterion can be applied. For example, if the control resource sets overlap in time during a specific PDCCH monitoring period, and if all control resource sets are connected to the UE-specific search space instead of the common search space (e.g., if criterion 1 is not met), the UE can omit the application of criterion 1 and apply criterion 2.

[0272] According to an embodiment, if a control resource set is selected based on the above criteria, the UE can further consider two aspects regarding the QCL information configured for the control resource set. First, if control resource set 1 has CSI-RS 1 as a reference signal with a QCL-TypeD relationship, and if CSI-RS 1 has a QCL-TypeD relationship with reference signal SSB 1, and if another control resource set 2 has a QCL-TypeD relationship with reference signal SSB 1, then the UE can consider that the two control resource sets 1 and 2 have different QCL-TypeD characteristics. Second, if control resource set 1 has CSI-RS 1 configured for cell 1 as a reference signal with a QCL-TypeD relationship, and if CSI-RS 1 has a QCL-TypeD relationship with reference signal SSB 1, and if control resource set 2 has a QCL-TypeD relationship with reference signal CSI-RS 2 configured for cell 2, and if CSI-RS 2 has a QCL-TypeD relationship with the same reference signal SSB 1, then the UE can consider that the two control resource sets have the same QCL-TypeD characteristics.

[0273] Figure 12 An example of a method for a UE to select a set of receivable control resources by considering priorities when receiving a downlink control channel in a wireless communication system, according to an embodiment of the present disclosure, is shown.

[0274] According to an embodiment, as an example, the UE can be configured to receive multiple control resource sets that overlap in time during a specific PDCCH monitoring period, and such multiple control resource sets can be connected to a common search space or a UE-specific search space for multiple cells. During the corresponding PDCCH monitoring period, control resource set 11215 connected to common search space 1 can exist in bandwidth portion 1 1200 of cell 1, and control resource set 11215 connected to common search space 1 and control resource set 2 1220 connected to UE-specific search space 2 can exist in bandwidth portion 1 1225 of cell 2. Control resource sets 1215 and 1220 can have a QCL-TypeD relationship with CSI-RS resource 1 configured in bandwidth portion 1 of cell 1, and control resource set 1225 can have a QCL-TypeD relationship with CSI-RS resource 1 configured in bandwidth portion 1 of cell 2. If Standard 1 is applied to the corresponding PDCCH monitoring time 1210, all other control resource sets with the same QCL-TypeD reference signal as control resource set 1 1215 can be received. Therefore, the UE can receive control resource sets 1210 and 1215 in the corresponding PDCCH monitoring time 1220.

[0275] According to an embodiment, as another example, the UE can be configured to receive multiple control resource sets that overlap in time during a specific PDCCH monitoring period, and such multiple control resource sets can be connected to a common search space or a UE-specific search space for multiple cells. During the corresponding PDCCH monitoring period, control resource set 1 1230 connected to UE-specific search space 1 and control resource set 2 1245 connected to UE-specific search space 2 can exist in the bandwidth portion 11250 of cell 1, and control resource set 1 1235 connected to UE-specific search space 1 and control resource set 2 1255 connected to UE-specific search space 3 can exist in the bandwidth portion 1 1260 of cell 2. Control resource sets 1245 and 1250 can have a QCL-TypeD relationship with CSI-RS resource 1 configured in bandwidth portion 1 of cell 1, control resource set 1255 can have a QCL-TypeD relationship with CSI-RS resource 1 configured in bandwidth portion 1 of cell 2, and control resource set 1260 can have a QCL-TypeD relationship with CSI-RS resource 2 configured in bandwidth portion 1 of cell 2. If standard 1 is applied to the corresponding PDCCH monitoring time 1240, there is no common search space, and therefore the next standard, i.e., standard 2, can be applied. If standard 2 is applied to the corresponding PDCCH monitoring time 1240, all other control resource sets with reference signals having the same QCL-TypeD as control resource set 1 1245 can be received. Therefore, the UE can receive control resource sets 1240 and 1245 in the corresponding PDCCH monitoring time 1250.

[0276] Regarding rate matching / drilling

[0277] The rate matching operation and the punching operation will be described in detail below.

[0278] If the time and frequency resources A used to transmit symbol sequence A overlap with time and frequency resources B, then considering resource C (the area where resources A and B overlap), rate matching or puncturing operations can be considered as operations of transmit / receive channel A. The specific operations can be described below.

[0279] Rate matching operation

[0280] According to an embodiment, the base station can transmit channel A after mapping it only to the remaining resource domains within the entire resource A, excluding resource C (the area overlapping with resource B), which will be used to transmit symbol sequence A to the UE. For example, if symbol sequence A is configured as {symbol #1, symbol #2, symbol #3, symbol #4}, if resource A is {resource #1, resource #2, resource #3, resource #4}, and if resource B is {resource #3, resource #5}, then the UE can receive symbol sequence A based on the assumption that symbol sequence A has been continuously mapped to the remaining resources {resource #1, resource #2, resource #4} within resource A, excluding {resource #3} (corresponding to resource C). Therefore, the base station can transmit symbol sequence {symbol #1, symbol #2, symbol #3} after mapping symbol sequence {symbol #1, symbol #2, symbol #3} to {resource #1, resource #2, resource #4} respectively.

[0281] According to an embodiment, the UE can evaluate resources A and B based on scheduling information about symbol sequence A from the base station, thereby evaluating resource C (the area where resources A and B overlap). The UE can receive symbol sequence A based on the assumption that symbol sequence A has been mapped and transmitted in the remaining area of ​​resource A, excluding resource C. For example, if symbol sequence A is configured as {symbol #1, symbol #2, symbol #3, symbol #4}, if resource A is {resource #1, resource #2, resource #3, resource #4}, and if resource B is {resource #3, resource #5}, then the UE can receive symbol sequence A based on the assumption that symbol sequence A has been continuously mapped to the remaining resources {resource #1, resource #2, resource #4} in resource A, excluding {resource #3} (corresponding to resource C). Therefore, the UE can perform a series of the following reception operations based on the assumption that symbol sequence {symbol #1, symbol #2, symbol #3} has been transmitted after being mapped to {resource #1, resource #2, resource #4} respectively.

[0282] Drilling operation

[0283] If there exists a resource C (an area overlapping with resource B) within the entire resource A that is to be used to send symbol sequence A to the UE, the base station can map symbol sequence A to the entire resource A, but can not perform transmission in the resource area corresponding to resource C, and can only perform transmission for the remaining resource area in resource A excluding resource C. For example, if symbol sequence A is configured as {symbol #1, symbol #2, symbol #3, symbol #4}, if resource A is {resource #1, resource #2, resource #3, resource #4}, and if resource B is {resource #3, resource #5}, then the UE can assume that symbol sequence A {symbol #1, symbol #2, symbol #3, symbol #4} is mapped to resource A {resource #1, resource #2, resource #3, resource #4} respectively, but does not send {symbol #3} mapped to {resource #3} (corresponding to resource C), and based on the assumption that the symbol sequence {symbol #1, symbol #2, symbol #4} corresponding to the remaining resources {resource #1, resource #2, resource #4} in resource A, excluding {resource #3} (corresponding to resource C), has been mapped and sent, the UE can receive the symbol sequence {symbol #1, symbol #2, symbol #4}. Therefore, the base station can send the symbol sequence {symbol #1, symbol #2, symbol #4} after mapping the symbol sequence {symbol #1, symbol #2, symbol #4} to {resource #1, resource #2, resource #4} respectively.

[0284] According to an embodiment, the UE can evaluate resource A and resource B based on scheduling information about symbol sequence A from the base station, thereby evaluating resource C (the area where resource A and resource B overlap). The UE can receive symbol sequence A based on the assumption that symbol sequence A has been mapped to the entire resource A but is only transmitted in the remaining area of ​​resource region A excluding resource C. For example, if symbol sequence A is configured as {symbol #1, symbol #2, symbol #3, symbol #4}, if resource A is {resource #1, resource #2, resource #3, resource #4}, and if resource B is {resource #3, resource #5}, then the UE can assume that symbol sequence A {symbol #1, symbol #2, symbol #3, symbol #4} is mapped to resource A {resource #1, resource #2, resource #3, resource #4} respectively, but does not send {symbol #3} mapped to {resource #3} (corresponding to resource C), and based on the assumption that the symbol sequence {symbol #1, symbol #2, symbol #4} corresponding to the remaining resources {resource #1, resource #2, resource #4} in resource A, excluding {resource #3} (corresponding to resource C), has been mapped and sent, the UE can receive the symbol sequence {symbol #1, symbol #2, symbol #4}. Therefore, the UE can perform a series of receiving operations based on the assumption that the symbol sequence {symbol #1, symbol #2, symbol #4} has been sent after being mapped to {resource #1, resource #2, resource #4} respectively.

[0285] The following describes a method for configuring rate matching resources in a 5G communication system for rate matching purposes. Rate matching refers to adjusting the signal size taking into account the amount of resources available for signal transmission. For example, data channel rate matching may mean mapping and transmitting data channels without regard to a specific time and frequency resource domain, and adjusting the data size accordingly.

[0286] Figure 11 An example of a method for transmitting / receiving data in a wireless communication system, according to an embodiment of the present disclosure, is shown, in which a base station and a UE consider downlink data channel and rate matching resources.

[0287] Figure 11 The diagram illustrates a downlink data channel (PDSCH) 1101 and rate matching resources 1102. The base station can configure one or more rate matching resources 1102 for the UE via upper-layer signaling (e.g., RRC signaling). The rate matching resource 1102 configuration information may include time-domain resource allocation information 1103, frequency-domain resource allocation information 1104, and periodic information 1105. Hereinafter, the bitmap corresponding to the frequency-domain resource allocation information 1104 will be referred to as the "first bitmap," the bitmap corresponding to the time-domain resource allocation information 1103 will be referred to as the "second bitmap," and the bitmap corresponding to the periodic information 1105 will be referred to as the "third bitmap." If all or some of the time and frequency resources of the scheduled PDSCH 1101 overlap with the configured rate matching resources 1102, the base station can rate match and transmit the PDSCH 1101 within the rate matching resource 1102 portion, and the UE can perform reception and decoding after assuming that the PDSCH 1102 has already been rate matched within the rate matching resource 1102 portion.

[0288] The base station can dynamically notify the UE via DCI whether to perform rate matching on the PDSCH in the configured rate matching resource section through additional configuration (e.g., corresponding to the "rate matching indicator" in the DCI format described above). Specifically, the base station can select some from the configured rate matching resources and group them into rate matching resource groups, and can indicate to the UE via DCI using a bitmap type whether rate matching of the PDSCH is performed for each rate matching resource group. For example, if four rate matching resources RMR#1, RMR#2, RMR#3, and RMR#4 are configured, the base station can configure rate matching groups RMG#1={RMR#1, RMR#2}, RMG#2={RMR#3, RMR#4}, and can indicate to the UE via a bitmap using two bits in the DCI field whether rate matching occurs in RMG#1 and RMG#2 respectively. For example, the base station can use "1" to indicate that rate matching is to be performed, and "0" to indicate that rate matching is not to be performed.

[0289] 5G supports both "RB symbol level" and "RE level" granularity as methods for configuring the aforementioned rate matching resources for the UE. More specifically, the following configuration methods can be followed.

[0290] RB symbol level

[0291] According to an embodiment, the UE may have up to four RateMatchPatterns configured for each bandwidth portion via upper-layer signaling, and a RateMatchPattern may include the following.

[0292] - This may include resources associated with reserved resources within the bandwidth portion, having time-domain and frequency-domain resource domains for corresponding reserved resources configured as a combination of RB-level bitmaps and symbol-level bitmaps in the frequency domain. Reserved resources may span one or two time slots. A time-domain pattern (periodicityAndPattern) may be additionally configured, wherein the time-domain and frequency-domain representations of the corresponding RB-level and symbol-level bitmap pairs are repeated.

[0293] - It can include resource regions corresponding to the time-domain patterns configured by the time-domain and frequency-domain resource regions configured by CORESET within the bandwidth portion, as well as the search space configuration of the corresponding resource regions that are repeated therein.

[0294] RE Level

[0295] According to an embodiment, the UE may have the following features configured via upper-layer signaling.

[0296] - Configuration information for the RE corresponding to the LTE CRS (Cell-Specific Reference Signal or Common Reference Signal) mode (lte-CRS-ToMatchAround) may include the LTE CRS port number (nrofCRS-Ports) and the LTE-CRS-vshift value (v-shift), the position information of the center subcarrier of the LTE carrier relative to the reference frequency point (e.g., reference point A) (carrierFreqDL), the bandwidth size of the LTE carrier (carrierBandwidthDL), and the subframe configuration information corresponding to the Multicast Broadcast Single Frequency Network (MBSFN) (mbsfn-SubframConfigList), etc. The UE can determine the position of the CRS within the NR slot corresponding to the LTE subframe based on the above information.

[0297] - It can include configuration information about resource sets corresponding to one or more zero-power (ZP) CSI-RS within the bandwidth portion.

[0298] Regarding LTE CRS rate matching

[0299] Next, the rate matching process for the aforementioned LTE CRS will be described in detail. In NR, for coexistence between Long Term Evolution (LTE) and New RAT (NR) (LTE-NR coexistence), the LTE Cell-Specific Reference Signal (CRS) mode can be configured for the NR UE. More specifically, the CRS mode can be provided through RRC signaling that includes at least one parameter within the ServingCellConfig IE (Information Element) or ServingCellConfigCommon IE. Examples of parameters may include lte-CRS-ToMatchAround, lte-CRS-PatternList1-r16, lte-CRS-PatternList2-r16, crs-RateMatch-PerCORESETPoolIndex-r16, etc.

[0300] Rel-15 NR provided a feature that allowed configuring one CRS pattern per serving cell via the parameter lte-CRS-ToMatchAround. Rel-16 NR has extended this feature to allow configuring multiple CRS patterns per serving cell. More specifically, a UE with a single TRP (Transmit and Receive Point) configuration can now have one CRS pattern per LTE carrier configuration, and a UE with a multi-TRP configuration can now have two CRS patterns per LTE carrier configuration. For example, a UE with a single TRP configuration can have up to three CRS patterns per serving cell configured via the parameter lte-CRS-PatternList1-r16. As another example, a UE with a multi-TRP configuration can have a CRS configured for each TRP. That is, the CRS pattern for TRP1 can be configured via the parameter lte-CRS-PatternList1-r16, and the CRS pattern for TRP2 can be configured via the parameter lte-CRS-PatternList2-r16. If two TRPs are configured as described above, the parameter crs-RateMatch-PerCORESETPoolIndex-r16 determines whether the CRS modes of both TRP1 and TRP2 are applied to a specific Physical Downlink Shared Channel (PDSCH) or only the CRS mode for one TRP is applied. If the parameter crs-RateMatch-PerCORESETPoolIndex-r16 is configured as "enabled", only the CRS mode of one TRP is applied, and otherwise both CRS modes of the two TRPs are applied.

[0301] Table 17 shows the ServingCellConfig IE including CRS mode, and Table 18 shows the RateMatchPatternLTE-CRS IE including at least one parameter regarding CRS mode.

[0302] Table 17

[0303]

[0304]

[0305]

[0306]

[0307]

[0308] Table 18

[0309]

[0310]

[0311] PDSCH: Regarding Frequency Resource Allocation

[0312] Figure 13 An example of frequency domain resource allocation for the Physical Downlink Shared Channel (PDSCH) in a wireless communication system according to embodiments of the present disclosure is shown.

[0313] Figure 13 Three frequency domain resource allocation methods are shown, which can be configured by the upper layer in an NR wireless communication system: type 0 1300, type 1 1301, and dynamic switching 1310.

[0314] refer to Figure 13 When the UE is configured to use only resource type 0 via upper-layer signaling (1300), the portion of downlink control information (DCI) used to allocate PDSCH to the UE includes N RBG A bitmap of N bits. The conditions used here will be described again later. As used in this article, N RBG This refers to the number of Resource Block Groups (RBGs) determined by the BWP size allocated by the BWP indicator and the upper-layer parameter rbg-Size, as shown in Table 19 below, and the data is sent in the rbg indicated by the bitmap as "1".

[0315] Table 19

[0316]

[0317] When the UE is configured to use only resource type 1 via upper-layer signaling (1305), part of the DCI includes frequency domain resource allocation information, which includes... Bits. The conditions used here will be described again later. Thus, the base station can configure the starting VRB 1320 and the length of the frequency domain resources continuously allocated from it 1325.

[0318] When a UE is configured to use both resource type 0 and resource type 1 (1310) simultaneously via upper-layer signaling, the portion of the DCI used to allocate the PDSCH to the corresponding UE includes frequency domain resource allocation information. This information comprises as many bits as the larger of the payloads 1315 used to configure resource type 0 and 1320 and 1325 used to configure resource type 1, which is 1335. The conditions for this will be described again later. A bit 1330 can be added to the beginning portion (MSB) of the frequency domain resource allocation information within the DCI, and if this bit has a value of "0", it indicates the use of resource type 0, and if this bit has a value of "1", it indicates the use of resource type 1.

[0319] PDSCH / PUSCH: Regarding Time Resource Allocation

[0320] The following section describes a method for allocating time-domain resources for data channels in next-generation mobile communication systems (5G or NR systems).

[0321] The base station can configure tables for the UE regarding time-domain resource allocation information for the Physical Downlink Shared Channel (PDSCH) and Physical Uplink Shared Channel (PUSCH) via upper-layer signaling (e.g., RRC signaling). A table with a maximum of maxNrofDL-Allocations=16 entries can be configured for the PDSCH, and a table with a maximum of maxNrofUL-Allocations=16 entries can be configured for the PUSCH. In an embodiment, the time-domain resource allocation information may include time slot timing from PDCCH to PDSCH (e.g., the time slot unit time interval corresponding to the time point between receiving the PDCCH and sending the PDSCH scheduled by the received PDCCH; denoted as K0), time slot timing from PDCCH to PUSCH (e.g., the time slot unit time interval corresponding to the time point between receiving the PDCCH and sending the PUSCH scheduled by the received PDCCH; hereinafter denoted as K2), the position and length information of the start symbol for scheduling the PDSCH or PUSCH within the time slot, the mapping type of the PDSCH or PUSCH, etc. For example, information such as that in Table 20 or Table 21 below can be sent from the base station to the UE.

[0322] Table 20

[0323]

[0324] Table 21

[0325]

[0326] The base station can notify the UF of one of the entries in the table regarding the aforementioned time-domain resource allocation information via L1 signaling (e.g., DCI). (For example, the "Time-domain Resource Allocation" field in the DCI can indicate the same content.) The UE can obtain time-domain resource allocation information about the PDSCH or PUSCH based on the DCI obtained from the base station.

[0327] Figure 14 An example of time-domain resource allocation for PDSCH in a wireless communication system according to an embodiment of the present disclosure is shown.

[0328] refer to Figure 14 The base station can determine the subcarrier spacing (SCS) of the data and control channels configured by the upper layer. μ PDSCH , μ PDCCH The time-domain location of the PDSCH resource is indicated by the scheduling offset (K0) value and the OFDM symbol start position 1400 and length 1405 within a time slot 1410 dynamically indicated by DCI.

[0329] Figure 15 An example of time-domain resource allocation for data channels and control channels based on subcarrier spacing is shown in a wireless communication system according to an embodiment of the present disclosure.

[0330] refer to Figure 15 If the data channel and control channel have the same subcarrier spacing (1500, μ PDSCH = μ PDCCH If the data channel and the control channel have different subcarrier spacings (1505, ...), then the time slot number used for data is the same as the time slot number used for control, and the base station and UE can accordingly generate a scheduling offset that conforms to the predetermined time slot offset K0. On the other hand, if the data channel and the control channel have different subcarrier spacings (1505, ...), ... μ PDSCH ≠ μ PDCCH If the time slot number used for data is different from the time slot number used for control, the base station and UE can generate a scheduling offset that is consistent with the predetermined time slot offset K0 of the subcarrier interval of the reference PDCCH.

[0331] PDSCH: TCI state activates MAC-CE

[0332] Next, the beam configuration method for PDSCH will be described.

[0333] Figure 16The process of beam configuration and activation of the PDSCH in a wireless communication system according to embodiments of the present disclosure is illustrated; the TCI state list for the PDSCH can be indicated by a higher-level list such as RRC (1600). For example, the TCI state list can be indicated by TCI-StateToAddModList and / or TCI-StateToReleaseList within a BWP-specific PDSCH-Config IE. Next, a portion of the TCI state list can be activated via MAC-CE (1620). The maximum number of activated TCI states can be determined by the UE reporting capability. According to an embodiment, one of the activated TCI states can be indicated by DCI (1640).

[0334] in addition, Figure 16 An example of the MAC-CE structure 1650 for PDSCH TCI state activation / deactivation is shown.

[0335] The meanings of the various fields in MAC CE and the configurable values ​​for each field are as follows.

[0336] Serving Cell ID (Serving Cell Identifier): This field indicates the identifier of the serving cell to which the MAC CE is applied. The field is 5 bits long. If the indicated serving cell is configured as part of simultaneousCI-UpdateList1 or simultaneousCI-UpdateList2 as specified in TS 38.331[5], then this MAC CE applies to all serving cells configured in the set simultaneousCI-UpdateList1 or simultaneousCI-UpdateList2, respectively.

[0337] BWP ID (Bandwidth Part Identifier): This field indicates the DL BWP to which the MAC CE applies, as a code point in the DCI Bandwidth Part Indicator field as specified in TS 38.212[9]. The BWP ID field is 2 bits long. This field is ignored if the MAC CE applies to a set of serving cells;

[0338] Ti (TCI State Identifier): If a TCI state with TCI-StateId i exists as specified in TS 38.331[5], this field indicates the active / deactivated state of the TCI state with TCI-StateId i; otherwise, the MAC entity should ignore the Ti field. The Ti field is set to 1 to indicate that the TCI state with TCI-StateId i should be activated and mapped to a code point in the DCI Transport Configuration Indication field, as specified in TS 38.214[7]. The Ti field is set to 0 to indicate that the TCI state with TCI-StateId i should be deactivated and not mapped to a code point in the DCI Transport Configuration Indication field. The code point to which a TCI state is mapped is determined by its ordinal position among all TCI states to which the Ti field is set to 1, i.e., the first TCI state to which the Ti field is set to 1 should be mapped to code point value 0, the second TCI state to which the Ti field is set to 1 should be mapped to code point value 1, and so on. The maximum number of active TCI states is 8;

[0339] CORESET Pool ID: This field indicates the mapping between the active TCI state and the code point indicated by the DCI transport configuration set by field Ti, specific to the ControlResourceSetId configured with CORESET Pool ID, as specified in TS 38.331[5]. This field set to 1 indicates that this MAC CE will be applied to DL transports scheduled by a CORESET with CORESET Pool ID equal to 1, otherwise, this MAC CE will be applied to DL transports scheduled by a CORESET with CORESET Pool ID equal to 0. If no coresetPoolIndex is configured for any CORESET, the MAC entity should ignore the CORESET Pool ID field in this MAC CE when receiving the MAC CE. If the serving cell in the MAC CE is configured in a cell list containing more than one serving cell, the CORESET Pool ID field should be ignored when receiving the MAC CE.

[0340] PUSCH: Regarding the transmission scheme

[0341] Next, the PUSCH transmission scheduling scheme will be described. PUSCH transmissions can be dynamically scheduled by UL authorization within the DCI, or operated using configured authorization type 1 or type 2. Dynamic scheduling instructions for PUSCH transmissions can be given via DCI format 0_0 or 0_1.

[0342] Configured grant type 1 PUSCH transports can be semi-statically configured via upper-layer signaling by receiving the configuredGrantConfig (including rrc-ConfiguredUplinkGrant) from Table 16, without receiving UL grants within the DCI. Configured grant type 2 PUSCH transports can be semi-persistently scheduled via UL grants within the DCI after receiving the configuredGrantConfig (excluding rrc-ConfiguredDuplinkGrant) from Table 22 via upper-layer signaling. If the PUSCH transport operates with configured grants, the parameters applied to the PUSCH transport are applied via the configuredGrantConfig (upper-layer signaling) from Table 22, in addition to the scaling of dataScramblingIdentityPUSCH, txConfig, codebookSubset, maxRank, and UCI-OnPUSCH provided by pusch-Config (upper-layer signaling) in Table 23. If a transformPrecoder is provided in configuredGrantConfig (upper-layer signaling) in Table 22, the UE will apply tp-pi2BPSK in pusch-Config in Table 23 to PUSCH transports with configured grant operations.

[0343] Table 22

[0344]

[0345]

[0346]

[0347] Next, the PUSCH transmission method will be described. The DMRS antenna port used for PUSCH transmission is the same as the antenna port used for SRS transmission. Depending on whether the value of txConfig in pusch-Config in Table 23, which serves as upper-layer signaling, is "codebook" or "nonCodebook", PUSCH transmission can follow either a codebook-based transmission method or a non-codebook-based transmission method.

[0348] As described above, PUSCH transmissions can be dynamically scheduled via DCI format 0_0 or 0_1, and can be semi-statically configured via configured authorization. When a scheduling instruction for a PUSCH transmission is received via DCI format 0_0, the UE performs beam configuration for the PUSCH transmission using the pucch-spatialRelationInfoID corresponding to the UE-specific PUCCH resource corresponding to the smallest ID in the active uplink BWP within the serving cell, and the PUSCH transmission is based on a single antenna port. The UE does not expect PUSCH transmissions to be scheduled via DCI format 0_0 in a BWP that does not have a PUCCH resource with a configuration including pucch-spatialRelationInfo. If the UE does not have a configured txConfig in the pusch-Config in Table 23, the UE does not expect scheduling via DCI format 0_1.

[0349] Table 23

[0350]

[0351]

[0352] Next, codebook-based PUSCH transmission will be described. Codebook-based PUSCH transmission can be dynamically scheduled via DCI format 0_0 or 0_1, and can be operated semi-statically with configured authorization. If codebook-based PUSCH is dynamically scheduled via DCI format 0_1 ​​or configured semi-statically with configured authorization, the UE determines the precoder used for PUSCH transmission based on the SRS Resource Indicator (SRI), Transport Precoding Matrix Indicator (TPMI), and transport rank (number of PUSCH transport layers).

[0353] SRIs can be indicated via SRS resource indicators (fields within the DCI) or configured via srs-ResourceIndicator (upper-layer signaling). During codebook-based PUSCH transmissions, a UE has at least one SRS resource configured for it and can have up to two SRS resources configured for it. If an SRI is provided to the UE via the DCI, the SRS resource indicated by the corresponding SRI refers to the SRS resource corresponding to the SRI among the SRS resources transmitted before the PDCCH including the corresponding SRI. Furthermore, TPMIs and transport rank can be given via "precoding information and number of layers" (fields within the DCI) or set via precodingAndNumberOfLayers (upper-layer signaling). TPMIs are used to indicate the precoder to be applied to PUSCH transmissions. If an SRS resource is configured for the UE, TPMIs can be used to indicate the precoder to be applied to the configured SRS resource. If multiple SRS resources are configured for the UE, TPMIs are used to indicate the precoder to be applied to the SRS resource indicated by the SRI.

[0354] The precoder to be used for PUSCH transmission is selected from the uplink codebook with the same number of antenna ports as the value of nrofSRS-Ports in the SRS-Config (upper-layer signaling). Regarding codebook-based PUSCH transmission, the UE determines the codebook subset based on the codebookSubset and TPMI in the push-Config (upper-layer signaling). Based on the UE capabilities reported to the base station, the codebook subset in the push-Config (upper-layer signaling) can be configured as one of "fullyAndPartialAndNonCoherent", "partialAndNonCoherent", or "noncoherent". If the UE reports "partialAndNonCoherent" as a UE capability, the UE does not expect the value of codebookSubset (upper-layer signaling) to be configured as "fullyAndPartialAndNonCoherent". Additionally, if the UE reports "noncoherent" as a UE capability, the UE does not expect the value of codebookSubset (upper-layer signaling) to be configured as "fullyAndPartialAndNonCoherent" or "partialAndNonCoherent". If nrofSRS-Ports (upper-layer signaling) in SRS-ResourceSet indicates two SRS antenna ports, the UE does not expect the value of codebookSubset (upper-layer signaling) to be configured as "partialAndNonCoherent".

[0355] A UE can have an SRS resource set configured for it, where the usage value in the SRS-ResourceSet (upper-layer signaling) is "codebook", and an SRS resource can be indicated by the SRI in the corresponding SRS resource set. If multiple SRS resources are configured in the SRS resource set, and the usage value (upper-layer signaling) in the SRS-ResourceSet is "codebook", the UE expects the value of nrofSRS-Ports (upper-layer signaling) in the SRS-Resource to be the same for all SRS resources.

[0356] The UE sends one or more SRS resources from a set of SRS resources configured as "codebook" to the base station according to upper-layer signaling. The base station selects one from the SRS resources sent by the UE and instructs the UE to transmit PUSCH using the transmission beam information of the corresponding SRS resource. In conjunction with codebook-based PUSCH transmission, the SRI is used as an index for selecting an SRS resource and is included in the DCI. Additionally, the base station adds information indicating the rank and TPMI to be used by the UE for PUSCH transmission to the DCI. Using the SRS resource indicated by the SRI, the UE can apply a precoder indicated by the rank and TPMI based on the transmission beam of the corresponding SRS resource when performing PUSCH transmission.

[0357] Next, non-codebook-based PUSCH transmissions will be described. Non-codebook-based PUSCH transmissions can be dynamically scheduled using DCI format 0_0 or 0_1, and can be operated semi-statically with configured authorization. If at least one SRS resource is configured within the SRS resource set, and the usage value in the SRS-ResourceSet (upper-layer signaling) is "nonCodebook", then non-codebook-based PUSCH transmissions can be scheduled for the UE using DCI format 0_1.

[0358] Regarding the SRS resource set, the usage value within the SRS-ResourceSet (upper-layer signaling) is "nonCodebook," which allows the UE to configure a connected NZP CSI-RS resource (non-zero power CSI-RS). The UE can calculate the precoder for SRS transmission by measuring the NZP CSI-RS resource connected to the SRS resource set. If the difference between the last received symbol of the non-periodic NZP CSI-RS resource connected to the SRS resource set and the first symbol of the non-periodic SRS transmission in the UE is less than 42 symbols, the UE does not expect the information about the precoder used for SRS transmission to be updated.

[0359] If the resourceType configuration value in the SRS-ResourceSet (upper-layer signaling) is "aperiodic", the connected NZP CSI-RS is indicated by an SRS request, which is a field within DCI format 0_1 ​​or 1_1. If the connected NZP CSI-RS resource is an aperiodic NZP CSI-RS resource, the presence of the connected NZP CSI-RS can be indicated if the value of the SRS request (a field within DCI format 0_1 ​​or 1_1) is not "00". The corresponding DCI should not indicate cross-carrier or cross-BWP scheduling. Additionally, if the SRS request value indicates the presence of an NZP CSI-RS, the NZP CSI-RS is located in the time slot used to transmit the PDCCH including the SRS request field. In this case, the TCI state configured for the scheduled subcarrier is not configured as QCL-TypeD.

[0360] If a periodic or semi-persistent SRS resource set is configured, the connected NZP CSI-RS can be indicated by the associated CSI-RS (upper-layer signaling) within the SRS-ResourceSet. Regarding non-codebook-based transmissions, the UE does not expect that spatialRelationInfo, which serves as upper-layer signaling regarding SRS resources, and the associated CSI-RS (upper-layer signaling) within the SRS-ResourceSet will be configured together.

[0361] If multiple SRS resources are configured for the UE, the UE can determine the precoder and transmission rank to be applied to PUSCH transmission based on the SRI indicated by the base station. The SRI can be indicated by an SRS resource indicator (a field within the DCI) or configured via the srs-ResourceIndicator (upper-layer signaling). Similar to the codebook-based PUSCH transmission described above, if the SRI is provided to the UE via the DCI, the SRS resource indicated by the corresponding SRI refers to the SRS resource corresponding to the SRI among those transmitted before the PDCCH containing the corresponding SRI. The UE can use one or more SRS resources for SRS transmission, and the maximum number of SRS resources that can be transmitted simultaneously in the same symbol within an SRS resource set, as well as the maximum number of SRS resources, is determined by the UE's capabilities reported to the base station. SRS resources transmitted simultaneously by the UE occupy the same RB. The UE configures one SRS port for each SRS resource. There can be only one configured SRS resource set, where the usage value in SRS-ResourceSet (upper-layer signaling) is "nonCodebook", and up to four SRS resources can be configured for non-codebook-based PUSCH transport.

[0362] The base station can send an NZP-CSI-RS connected to the SRS resource set to the UE, and the UE can calculate the precoder to be used when transmitting one or more SRS resources within the corresponding SRS resource set based on the measurement results when the corresponding NZP-CSI-RS is received. When transmitting one or more SRS resources within the SRS resource set to the base station, the UE applies the calculated precoder, configured for "non-codebook" purposes, and the base station selects one or more SRS resources from the received one or more SRS resources. Regarding non-codebook-based PUSCH transmission, the SRI indication can represent an index of one or more SRS resources or a combination of SRS resources, and the SRI is included in the DCI. The number of SRS resources indicated by the SRI sent by the base station can be the number of transport layers of the PUSCH, and the UE transmits the PUSCH by applying the precoder applied to the SRS resource transmission to each layer.

[0363] UE Capability Report

[0364] In LTE and NR, the UE can perform a procedure in which, upon connecting to a serving base station, the UE reports the capabilities it supports to the corresponding base station. In the following description, this procedure will be referred to as UE capability reporting.

[0365] According to an embodiment, a base station can transmit a UE capability query message to a UE in a connected state to request capability reports. This message may include UE capability requests for each Radio Access Technology (RAT) type of the base station. RAT type-specific requests may include supported frequency band combination information, etc. Furthermore, in the case of a UE capability query message, UE capabilities for multiple RAT types can be requested through a single RRC message container sent by the base station, or the base station may transmit a UE capability query message including multiple UE capability requests for each RAT type. That is, capability queries can be repeated multiple times in a single message, and the UE can configure corresponding UE capability information messages and report the message multiple times. In next-generation mobile communication systems, UE capability requests can be made regarding multiple RAT dual connectivity (MR-DC) such as NR, LTE, and E-UTRA-NR dual connectivity (EN-DC). Typically, a UE capability query message can be initially sent after the UE connects to the base station, but the base station can request a UE capability query message under any circumstances if required.

[0366] When the UE receives a UE capability report request from the base station in the above steps, the UE can configure its capabilities based on the frequency band information and RAT type requested by the base station. The methods for configuring UE capabilities in the NR system are summarized as follows:

[0367] 1. If the UE receives a list of LTE and / or NR frequency bands from the base station upon a UE capability request, the UE constructs a frequency band combination (BC) for EN-DC and NR Independent (SA). That is, the UE configures a candidate list of BCs for EN-DC and NR SAs based on the frequency bands received from the base station upon a request via FreqBandList. The frequency bands are prioritized according to the order described in the FreqBandList.

[0368] 2. If the base station sets the “eutra-nr-only” flag or the “eutra” flag and requests a UE capability report, the UE removes all content related to NR SA BC from the configured BC candidate list. This operation can only occur if the LTE base station (eNB) requests “eutra” capability.

[0369] 3. The UE then removes the backed-down BC from the BC candidate list configured in the above steps. As used herein, a backed-down BC refers to a BC that can be obtained by removing the frequency band corresponding to at least one SCell from a specific BC, and since the backed-down BC can be omitted because the BC prior to removing the frequency band corresponding to at least one SCell already covers it, this step also applies to MR-DC, i.e., LTE frequency bands are also applied. The remaining BCs after the above steps constitute the final "candidate BC list".

[0370] 4. The UE can select a BC suitable for the requested RAT type from the final "Candidate BC List" and choose the BC to report. In this step, the UE configures the supportedBandCombinationList in a defined order. That is, the UE configures the BC and UE capabilities to report according to the pre-configured RAT type order (NR->EUTRA-NR->EUTRA). Additionally, the UE can configure the featureSetCombination for the configured supportedBandCombinationList and configure a list of "Candidate Feature Set Combinations" from the candidate BC list, removing the list of fallback BCs (including capabilities of the same or lower steps). The "Candidate Feature Set Combinations" can include all feature set combinations for NR and EUTRA-NR BCs and can be obtained from the feature set combinations of the containers of UE-NR-Capabilities and UE-MRDC-Capabilities.

[0371] 5. If the requested RAT type is eutra-nr and has an impact, then featureSetCombinations are included in both the UE-MRDC-Capabilities and UE-NR-Capabilities containers. However, the NR feature set is only included in UE-NR-Capabilities.

[0372] After configuring UE capabilities, the UE transmits a UE capability information message, including the UE capabilities, to the base station. The base station then performs scheduling and transmit / receive management appropriate to the UE based on the UE capabilities received from the UE.

[0373] About CA / DC

[0374] Figure 17 The radio protocol structures of a base station and a UE in a wireless communication system according to embodiments of the present disclosure are shown in single-cell, carrier aggregation, and dual connectivity scenarios.

[0375] refer to Figure 17 The radio protocols of the next-generation mobile communication system include NR Service Data Adaptation Protocol (SDAP) 1725 or 1770, NR Packet Data Convergence Protocol (PDCP) 1730 or 1765, NR Radio Link Control (RLC) 1735 or 1760, and NR Media Access Control (MAC) 1740 or 1755 on each of the UE and NR base station sides.

[0376] The main functions of NR SDAP 1725 or 1770 may include some of the following functions.

[0377] - Transmission of user plane data

[0378] - Mapping between QoS flows and DRB for both DL and UL

[0379] - Mark QoS flow IDs in DL and UL groups

[0380] - Reflection QoS flow to DRB mapping for UL SDAP PDU

[0381] Regarding SDAP layer devices, the UE can be configured via RRC messages to use the SDAP layer device header or to use the SDAP layer device functionality for each PDCP layer device, each bearer, or each logical channel. If the SDAP header is configured, a 1-bit indicator for Non-Access Stratum (NAS) QoS reflection configuration (NAS reflected QoS) and a 1-bit indicator for AS QoS reflection configuration (AS reflected QoS) can be included in the SDAP header. This allows the UE to update or reconfigure the mapping information for uplink and downlink QoS flows and data bearers. The SDAP header can include QoS flow ID information indicating QoS. QoS information can be used for data processing priority, scheduling information, etc., to smoothly support service.

[0382] The main functions of NR PDCP 1730 or 1765 may include some of the following:

[0383] - Header compression and decompression: ROHC only

[0384] - Transmission of user data

[0385] - Sequential delivery of upper-layer PDUs

[0386] - Unordered delivery of upper-layer PDUs

[0387] - Reordering of received PDCP PDUs

[0388] - Duplicate detection of lower-level SDUs

[0389] - PDCP SDU retransmission

[0390] - Encryption and decryption

[0391] - Timer-based SDU dropping in the uplink

[0392] The reordering of the aforementioned NR PDCP device refers to the function of reordering PDCP PDUs received from the lower layer according to the order based on the PDCP sequence number (SN), and may include the function of transmitting data to the upper layer in the reordered order. Alternatively, the reordering of the NR PDCP device may include the function of immediately transmitting data regardless of order, the function of recording PDCP PDUs lost due to reordering, the function of reporting the status of lost PDCP PDUs to the transmitting side, and the function of requesting retransmission of lost PDCP PDUs.

[0393] The main functions of NR RLC 1735 or 1760 may include some of the following functions.

[0394] - Transmission of upper-layer PDUs

[0395] - Sequential delivery of upper-layer PDUs

[0396] - Unordered delivery of upper-layer PDUs

[0397] - Error correction via ARQ

[0398] - Cascading, segmentation, and reassembly of RLC SDUs

[0399] - Resegmentation of RLC data PDUs

[0400] - Reordering of RLC data PDUs

[0401] - Duplicate Detection

[0402] - Protocol error detection

[0403] - RLC SDU discard

[0404] - RLC Reconstruction

[0405] In-order delivery by an NR RLC device refers to the function of sequentially delivering RLC SDUs received from a lower layer to an upper layer. In-order delivery by an NR RLC device may include the function of reassembling and delivering multiple received RLC SDUs, where one original RLC SDU has been segmented into multiple RLC SDUs; the function of reordering received RLC PDUs with reference to the RLC sequence number (SN) or PDCP sequence number (SN); the function of recording RLC PDUs lost due to reordering; the function of reporting the status of lost RLC PDUs to the transmitting side; and the function of requesting retransmission of lost RLC PDUs. The in-order delivery function of an NR RLC device may include the following functions: if a lost RLC SDU exists, only RLC SDUs preceding the lost RLC SDU are consecutively delivered to the upper layer; and may include the following functions: if a predetermined timer has expired despite the existence of a lost RLC SDU, all RLC SDUs received before the timer started are consecutively delivered to the upper layer. Alternatively, the sequential delivery of NR RLC devices may include the following functionality: if a lost RLC SDU has expired but a predetermined timer has expired, all currently received RLC SDUs are delivered sequentially to the upper layer. Additionally, the sequential delivery of NR RLC devices may include the functionality of processing RLC PDUs in the order of reception (regardless of sequence number order, order of arrival) and delivering them to the PDCP device regardless of order (out-of-order delivery), and may include the functionality of receiving segments stored in a buffer or to be received later in the case of fragmentation, reconfiguring them into a complete RLC PDU, processing them, and delivering them to the PDCP device. The NR RLC layer may not include concatenation functionality; concatenation functionality may be performed in the NRMAC layer, or it may be replaced by multiplexing functionality of the NR MAC layer.

[0406] NR RLC out-of-order delivery refers to the function of immediately delivering RLC SDUs received from the lower layer to the upper layer regardless of the order. It may include the function of reassembling and delivering multiple RLC SDUs that are segments of a single original RLC SDU if they are received. It may also include the function of storing the RLC SN or PDCP SN of the received RLC PDUs and recording RLC PDUs lost due to reordering.

[0407] The NR MAC 1740 or 1755 can connect to multiple NR RLC layer devices configured in a single UE, and the main functions of the NR MAC can include some of the following functions.

[0408] - Mapping between logical channels and transport channels

[0409] - MAC SDU multiplexing / demultiplexing

[0410] - Scheduling Information Report

[0411] - Error correction via HARQ

[0412] Priority handling between logical channels of a UE

[0413] - Prioritize UEs through dynamic scheduling

[0414] - MBMS service identifier

[0415] - Transmission format selection

[0416] - Fill

[0417] The NR PHY layer 1745 or 1750 can perform channel coding and modulation operations on upper-layer data to obtain OFDM symbols and deliver them via radio channels, or demodulate OFDM symbols received via radio channels, perform channel decoding, and deliver them to the upper layer.

[0418] The detailed structure of a radio protocol architecture can vary depending on the carrier (or cell) operation scheme. For example, when a base station transmits data to a UE based on a single carrier (or cell), the base station and UE can use a protocol architecture with a single structure for each layer, such as 1700. On the other hand, when a base station transmits data to a UE based on carrier aggregation (CA) using multiple carriers in a single TRP, the base station and UE can use a protocol architecture with a single structure up to RLC but multiplexing the PHY layer through the MAC layer, such as 1710. As another example, when a base station transmits data to a UE based on dual connectivity (DC) using multiple carriers in multiple TRPs, the base station and UE can use a protocol architecture with a single structure up to RLC but multiplexing the PHY layer through the MAC layer, such as 1720.

[0419] Referring to the above description of PDCCH and beam configuration, current Rel-15 and Rel-16 NR do not support PDCCH retransmission, which may make it difficult to achieve the required reliability in scenarios requiring high reliability, such as URLLC. This disclosure can improve the PDCCH reception reliability of the UE by providing a PDCCH retransmission method through multiple transmission points (TRPs). Specific methods will be described below through the following embodiments.

[0420] In the following, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The content of this disclosure can be applied to FDD and TDD systems. As used herein, upper-layer signaling (or upper-layer signaling) is a method of transmitting signals from a base station to a UE using a downlink data channel of the physical layer, or transmitting signals from a UE to a base station using an uplink data channel of the physical layer, and may also be referred to as "RRC signaling", "PDCP signaling" or "MAC control unit (MAC CE)".

[0421] In the following, within this disclosure, the UE may use various methods to determine whether cooperative communication is applied. For example, the PDCCH allocating the PDSCH for cooperative communication may have a specific format, or the PDCCH allocating the PDSCH for cooperative communication may include a specific indicator indicating whether cooperative communication is applied, or the PDCCH allocating the PDSCH for cooperative communication may be scrambled by a specific RNTI, or cooperative communication may be assumed to be applied within a specific range indicated by the upper layer. In the following, for ease of description, it will be assumed that the NC-JT case refers to the case where the UE receives the PDSCH for cooperative communication based on conditions similar to those described above.

[0422] In the following text, determining the priority between A and B can be described differently, for example, by selecting the entity with higher priority according to a predetermined priority rule and performing the corresponding operation, or by omitting or discarding operations concerning the entity with lower priority.

[0423] The above examples can be described below through several embodiments, but they are not independent of each other and one or more embodiments can be applied simultaneously or in combination.

[0424] Regarding NC-JT

[0425] According to embodiments of this disclosure, in order to receive PDSCH from multiple TRPs, the UE can use noncoherent joint transmission (NC-JT).

[0426] Unlike traditional systems, 5G wireless communication systems can support all services with very short transmission latency, services requiring high connection density, and services requiring high transmission rates. In wireless communication networks that include multiple cells, transmit and receive points (TRPs) or beams, coordinated transmission between cells, TRPs, and / or beams can meet various service requirements by increasing the strength of the signal received by the UE or effectively controlling interference between cells, TRPs, and / or beams.

[0427] Joint transmission (JT) is a representative transmission technology for coordinated communication. It can transmit signals to a UE through different cells, TRPs, and / or beams, thereby increasing the strength or throughput of the received signal at the UE. Here, the channels between each cell, TRP, and / or beam and the UE can have different characteristics. In particular, noncoherent joint transmission (NC-JT) that supports non-interference coding between cells, TRPs, and / or beams may require separate precoding, MCS, resource allocation, and TCI indication based on the channel characteristics of each link between each cell, TRP, and / or beam and the UE.

[0428] The aforementioned NC-JT transmission can be applied to at least one of the downlink data channel (PDSCH), downlink control channel (PDCCH), uplink data channel (PUSCH), and uplink control channel (PUCCH). During PDSCH transmission, transmission information such as precoding, MCS, resource allocation, and TCI can be indicated via DL DCI and should be indicated independently for each cell, TRP, and / or beam of the NC-JT. This is a significant factor in increasing the payload required for DL ​​DCI transmission, which can adversely affect the reception performance of the PDCCH used to transmit DCI. Therefore, to support JT with PDSCH, a careful trade-off between the amount of DCI information and the reception performance of control information is required.

[0429] Figure 18 An example of antenna port configuration and resource allocation for transmitting PDSCH using cooperative communication in a wireless communication system according to an embodiment of the present disclosure is shown.

[0430] refer to Figure 18 For each scheme of Joint Transmission (JT), an example of PDSCH transmission is described, and an example of allocating radio resources for each TRP is also described.

[0431] refer to Figure 18 Example 1800 shows coherent joint transmission (C-JT) that supports phase interference coding between individual cells, TRPs and / or beams.

[0432] In the C-JT scenario, TRP A 1805 and TRP B 1810 send a single data packet (PDSCH) to UE 1815, and multiple TRPs can perform joint precoding. This means that TRP A 1805 and TRP B 1810 send DMRS through the same DMRS port to transmit the same PDSCH. For example, TRP A 1805 and TRP B 1810 can send DMRS to the UE through DMRS port A and DMRS port B, respectively. In this case, the UE can receive a DCI message for receiving a PDSCH based on the DMRS demodulation sent through DMRS port A and DMRS port B.

[0433] According to an embodiment, Figure 18 Example 1820 shows noncoherent joint transmission (NC-JT) with non-interference coding between each cell, TRP, and / or beam for PDSCH transmission.

[0434] In the NC-JT scenario, PDSCH is transmitted to UE1835 for each cell, each TRP, and / or each beam, and individual precoding can be applied to each PDSCH. Individual cells, TRPs, and / or beams (1825, 1830) can send different PDSCHs or different PDSCH layers to the UE, thereby improving throughput compared to single-cell, TRP, and / or beam transmission. Furthermore, individual cells, TRPs, and / or beams can repeatedly transmit the same PDSCH to the UE, thereby improving reliability compared to single-cell, TRP, and / or beam transmission. For ease of description, cells, TRPs, and / or beams are often referred to as TRPs.

[0435] In this case, various wireless resource allocations can be considered, such as the case where multiple TRPs use the same frequency and time resources for PDSCH transmission (1840), the case where multiple TRPs use completely non-overlapping frequency and time resources (1845), and the case where some of the frequency and time resources used by multiple TRPs overlap with each other (1850).

[0436] To support NC-JT, various forms, structures, and relationships of DCI can be considered to simultaneously assign multiple PDSCHs to a single UE.

[0437] Figure 19 An example of downlink control information (DCI) configuration for cooperative communication in a wireless communication system according to embodiments of the present disclosure is shown. More specifically, Figure 19An example of downlink control information (DCI) configuration of an NC-JT in a wireless communication system according to an embodiment of the present disclosure is shown, wherein each TRP sends different PDSCHs or different PDSCH layers to the UE.

[0438] refer to Figure 19 Case #1 1900 is an example where (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 a single PDSCH transmission. In this case, the control information for the PDSCHs transmitted from the (N-1) additional TRPs is transmitted independently from the control information for the PDSCHs transmitted from the serving TRP. That is, the UE can obtain the control information for the PDSCHs transmitted from different TRPs (TRP#0 to TRP#(N-1)) through independent DCIs (DCI#0 to DCI#(N-1)). The formats of these independent DCIs can be the same or different from each other, and the payloads of the DCIs can also be the same or different from each other. → In Case #1 above, the freedom of PDSCH control or allocation can be fully guaranteed; however, when individual DCIs are transmitted by different TRPs, differences in DCI coverage may arise, and reception performance may degrade.

[0439] Case #2 1905 is an example in which (N-1) different PDSCHs are sent from (N-1) additional TRPs (TRP #1 to TRP #(N-1)) other than the serving TRP (TRP #0) used for a single PDSCH transmission, and control information (DCI) for the PDSCHs of the (N-1) additional TRPs is sent, with each DCI depending on the control information of the PDSCH sent from the serving TRP.

[0440] For example, the control information DCI#0 sent from the serving TRP (TRP#0) may include all information elements of DCI format 1_0, DCI format 1_1, and DCI format 1_2. However, the shortened DCI (hereinafter referred to as sDCI) (sDCI#0 to sDCI#(N-2)) for the control information of the PDSCH sent from the cooperating TRPs (TRP#1 to TRP#(N-1)) may only include some information elements of DCI format 1_0, DCI format 1_1, and DCI format 1_2. Therefore, the sDCI used to send control information for the PDSCH sent from the cooperating TRP has a smaller payload than the normal DCI (nDCI) used to send control information related to the PDSCH sent from the serving TRP, and thus may include reserved bits compared to the nDCI.

[0441] In scenario #2 above, the degree of freedom for controlling or allocating each PDSCH can be limited based on the content of the information elements included in the sDCI. However, the reception capability of the sDCI is superior to that of the nDCI, and therefore the probability of generating differences between DCI coverage areas may become lower.

[0442] Case #3 1910 is an example in which (N-1) different PDSCHs are sent from (N-1) additional TRPs (TRP #1 to TRP #(N-1)) other than the serving TRP (TRP #0) used for a single PDSCH transmission, and a control message of the PDSCHs of the (N-1) additional TRPs is sent and the DCI depends on the control message of the PDSCHs sent from the serving TRP.

[0443] For example, in the case of DCI#0, which is control information for PDSCH sent from the serving TRP (TRP#0), all information elements of DCI format 1_0, DCI format 1_1, and DCI format 1_2 can be included. In the case of control information for PDSCH sent from the cooperating TRPs (TRP#1 to TRP#(N-1)), only some information elements of DCI format 1_0, DCI format 1_1, and DCI format 1_2 can be aggregated into a single “secondary” DCI (sDCI) and sent. For example, the sDCI can include at least one HARQ-related information, such as the frequency domain resource allocation and time domain resource allocation of the cooperating TRP, and the MCS. Additionally, information not included in the sDCI (such as the bandwidth portion (BWP) indicator and carrier indicator) can follow the serving TRP's DCI (DCI#0, normal DCI, or nDCI).

[0444] In case #3 1910, the degree of freedom for PDSCH control or allocation can be limited based on the content of the information elements included in the sDCI, but the reception performance of the sDCI can be controlled, and case #3 1130 can have a smaller UE DCI blind decoding complexity compared to case #1 1900 or case #2 1905.

[0445] Case #4 1915 is an example where (N-1) different PDSCHs are transmitted from (N-1) additional TRPs (TRP#1 to TRP#(N-1)) besides the serving TRP (TRP#0) used for a single PDSCH transmission. The control information for the PDSCHs transmitted from the (N-1) additional TRPs is transmitted in the same DCI (long DCI) as the control information for the PDSCHs transmitted from the serving TRP. That is, the UE can obtain the control information for PDSCHs transmitted from different TRPs (TRP#0 to TRP#(N-1)) through a single DCI. In Case #4 1915, the complexity of the UE's blind DCI decoding may not increase, but the degree of freedom in PDSCH control or allocation may be lower because the number of cooperating TRPs is limited according to the long DCI payload constraint.

[0446] In the following description and embodiments, sDCI may refer to various supplementary DCIs that include PDSCH control information sent in the cooperative TRP, such as shortened DCI, auxiliary DCI, or normal DCI (DCI formats 1_0 and 1_1 above), and unless specific limitations are mentioned, the corresponding descriptions may be similarly applied to various supplementary DCIs.

[0447] In the following description and embodiments, cases #11900, #2 1905, and #3 1910, where one or more DCIs (or PDCCHs) are used to support NC-JT, can be classified as NC-JT based on multiple PDCCHs, and case #4 1915, where a single DCI (or PDCCH) is used to support NC-JT, can be classified as NC-JT based on a single PDCCH. In PDSCH transmission based on multiple PDCCHs, the CORESET of the DCI used to schedule the serving TRP (TRP#0) is separate from the CORESET of the DCI used to schedule the cooperating TRPs (TRP#1 to TRP#(N-1)). The method of distinguishing CORESETs may include a method of distinguishing by a higher-layer indicator for each CORESET and a method of distinguishing by a beam configuration for each CORESET. Furthermore, in NC-JT based on a single PDCCH, a single DCI schedules a single PDSCH with multiple layers instead of scheduling multiple PDSCHs, and multiple layers can be sent from multiple TRPs. In this case, the association between a layer and the TRP of the corresponding layer can be indicated by the Transport Configuration Indicator (TCI) for the layer.

[0448] According to embodiments of this disclosure, when applied in practice, “cooperative TRP” can be replaced by various terms such as “cooperative panel” or “cooperative beam”.

[0449] According to embodiments of this disclosure, "the case of applying NC-JT" can be interpreted in various ways as "the case where the UE simultaneously receives one or more PDSCHs in a BWP", "the case where the UE simultaneously receives PDSCHs in a BWP based on two or more Transport Configuration Indicators (TCIs)", and "the case where the PDSCHs received by the UE are associated with one or more DMRS port groups", but for ease of description, one expression is used.

[0450] In this disclosure, the wireless protocol architecture for NC-JT can be used depending on the TRP development scenario. For example, if there is no backhaul delay or a small backhaul delay exists between cooperating TRPs, a method utilizing a MAC layer multiplexing-based architecture (similar to the CA approach) can be used. On the other hand, when the backhaul delay between cooperating TRPs is too large to be ignored (e.g., when it takes 2 ms or longer to exchange information such as CSI, scheduling, and HARQ-ACK between cooperating TRPs), a method ensuring robustness to delay can be used through an independent architecture for each TRP from the RLC layer (similar to the DC approach).

[0451] UEs supporting C-JT / NC-JT can receive C-JT / NC-JT related parameters or settings from higher-level configurations and set their RRC parameters accordingly. For higher-level configurations, the UE can use UE capability parameters, such as tci-StatePDSCH. Here, UE capability parameters, such as tci-StatePDSCH, can define the TCI states of PDSCH transmissions. The number of TCI states can be configured as 4, 8, 16, 32, 64, and 128 in FR1, and as 64 and 128 in FR2. Up to eight states can be configured via MAC CE messages, indicated by the 3 bits of the TCI field in the DCI. The maximum value of 128 refers to the value indicated by maxNumberConfiguredTCIstatesPerCC within the parameter tci-StatePDSCH included in the UE's capability signaling. As described above, this series of configuration procedures from higher-level configuration to MAC CE configuration can be applied to beamforming indications or beamforming change commands for at least one PDSCH in a TRP.

[0452] Multi-DCI-based Multi-TRP

[0453] As an embodiment of this disclosure, a multi-DCI-based multi-TRP transmission method is described. In this multi-DCI-based multi-TRP transmission method, the downlink control channel for NC-JT can be configured based on multiple PDCCHs.

[0454] In NC-JT based on multiple PDCCHs, a CORESET or search space distinct for each TRP can be provided during DCI transmission for PDSCH scheduling of each TRP. The CORESET or search space for each TRP can be configured to be at least one of the following:

[0455] Configuration of higher-level indices for each CORESET: The CORESET configuration information configured through higher-level settings can include index values, and the index values ​​configured for each CORESET can be used to distinguish the TRPs that send PDCCHs within the corresponding CORESET. That is, in a set of CORESETs with the same higher-level index value, it can be assumed that the same TRP sends PDCCHs or sends PDSCHs scheduled for the same TRP. The index for each CORESET can be called the CORESETPoolIndex, and it can be assumed that the PDCCH is transmitted from the same TRP within a CORESET configured to have the same CORESETPoolIndex value. For CORESETs without a configured CORESETPoolIndex value, it can be assumed that a default value for the CORESETPoolIndex is configured, and the default value can be 0.

[0456] In this disclosure, if the number of CORESETPoolIndex types of multiple CORESETs included in the higher-layer signaling PDCCH-Config exceeds 1, that is, if each CORESET has a different CORESETPoolIndex value, then the UE can consider that the base station is capable of using the multi-TRP transmission method based on multiple DCI.

[0457] Conversely, in this disclosure, if the number of CORESETPoolIndex types of multiple CORESETs included in the higher-layer signaling PDCCH-Config is 1, that is, if all CORESETs have the same CORESETPoolIndex value of 0 or 1, then the UE can assume that the base station performs transmission by using a single TRP instead of using a multi-TRP transmission method based on multiple DCIs.

[0458] Configuring multiple values ​​for PDCCH-Config: Multiple values ​​for PDCCH-Config can be configured in a BWP. Each value of PDCCH-Config can include TRP-specific PDCCH configurations. That is, a list of CORESETs and / or a list of search spaces for each TRP can be configured in a single value of PDCCH-Config, and one or more CORESETs and one or more search spaces included in a single value of PDCCH-Config can be considered to correspond to a specific TRP.

[0459] CORESET beam / beam group configuration: By configuring a beam or beam group for each CORESET, the TRP corresponding to the corresponding CORESET can be distinguished. For example, if the same TCI state is configured for multiple CORESETs, it can be assumed that the CORESET is sent through the same TRP, or that the PDCCH of the PDSCH scheduled for the same TRP is sent in the CORESET.

[0460] Search Space Beam / Beamgroup Configuration: Configure a beam or beamgroup for each search space, and use it to distinguish the TRPs for each search space. For example, if the same beam / beamgroup or TCI state is configured for multiple search spaces, it can be assumed that the same TRP is sending PDCCH in the search space, or that the same TRP is sending PDSCHs scheduled for the same TRP in the search space.

[0461] As mentioned above, the CORESET or search space is distinguished by each TRP, thereby allowing the PDSCH and HARQ-ACK information of each TRP to be classified, thus enabling the independent generation of HARQ-ACK codebooks and the independent use of each TRP's PUCCH resources.

[0462] The above configuration can be independent for each cell or each BWP. For example, two different values ​​for CORESETPoolIndex can be configured for a PCell, while conversely, a value for CORESETPoolIndex can be left unconfigured for a specific SCell. In this case, it can be assumed that NC-JT is configured in the PCell, but not in the SCell where a value for CORESETPoolIndex is not configured.

[0463] According to the embodiments, the PDSCH TCI state activation / deactivation MAC-CE applicable to the multi-DCI-based multi-TRP transmission method can follow the above. Figure 16If the CORESETPoolIndex for all CORESETs in the higher-layer signaling PDCCH-Config is not configured for the UE, the UE can ignore the CORESET Pool ID field 1655 in MAC-CE 1650. If the UE can support a multi-DCI-based multi-TRP transmission method, i.e., if the individual CORESETs in the higher-layer signaling PDCCH-Config have different CORESETPoolIndex values, the UE can activate the TCI state in the DCIs included in the PDCCH transmitted from a CORESET that has the same CORESETPoolIndex value as the CORESETPoolID field 1655 in MAC-CE 1650. For example, if the value of the CORESETPoolID field 1655 in MAC-CE 1650 is 0, the TCI state in the DCIs included in the PDCCH transmitted from a CORESET with a CORESETPoolIndex of 0 can follow the activation information of MAC-CE.

[0464] When the UE is configured by the base station to use the multi-DCI-based multi-TRP transmission method, that is, when the number of CORESETPoolIndex types of multiple CORESETs included in the higher-layer signaling PDCCH-Config exceeds 1, or when each CORESET has a different CORESETPoolIndex value, the UE can identify that the PDSCH scheduled by the PDCCH in each CORESET with two different CORESETPoolIndex values ​​has the following limitations.

[0465] If the PDSCHs indicated by the PDCCHs in different CORESETs with two different CORESETPoolIndex values ​​completely or partially overlap, the UE can apply the TCI states indicated by the PDCCHs to different CDM groups respectively. That is, two or more TCI states may not be applied to a single CDM group.

[0466] If the PDSCHs indicated by the PDCCHs in each of the two different CORESETs with two different CORESETPoolIndex values ​​completely or partially overlap each other, the UE can expect the PDSCHs to have the same number of actual frontloaded DMRS symbols, the same number of actual additional DMRS symbols, actual DMRS symbols in the same location, and the same DMRS type.

[0467] The UE can expect that the bandwidth portions indicated by the PDCCH in the corresponding CORESET with two different CORESETPoolIndex are the same, and the subcarrier spacing is also the same.

[0468] The UE can expect that information about the PDSCH scheduled by the PDCCH in the CORESET, which has two different CORESETPoolIndexs, will be fully included in the corresponding PDCCH.

[0469] Multi-TRP based on a single DCI

[0470] As an embodiment of this disclosure, a multi-TRP transmission method based on a single DCI is described. In this multi-TRP transmission method based on a single DCI, the downlink control channel for NC-JT can be configured based on a single PDCCH.

[0471] In a multi-TRP transmission method based on a single DCI, PDSCHs transmitted by multiple TRPs can be scheduled using a single DCI. The number of TRPs transmitting PDSCHs can be used as a method to indicate the number of TCI states. That is, if the number of TCI states indicated in the DCI scheduling PDSCHs is 2, the transmission can be considered an NC-JT based on a single PDCCH, and if the number of TCI states is 1, the transmission can be considered a single-TRP transmission. The TCI states indicated in the DCI can correspond to one or two TCI states activated by MAC-CE. If the TCI states in the DCI correspond to two TCI states activated by MAC-CE, then the TCI code points indicated in the DCI and the TCI states activated by MAC-CE can have a correspondence, and this can correspond to the case where the number of TCI states activated by MAC-CE and corresponding to the TCI code points is 2.

[0472] As another example, if at least one code point among all code points in the TCI state field of the DCI indicates two TCI states, the UE can assume that the base station is capable of performing transmission according to a multi-TRP method based on a single DCI. At least one code point indicating two TCI states in the TCI state field can be activated via Enhanced PDSCH TCI State Activation / Deactivation MAC-CE.

[0473] Figure 20 An enhanced PDSCH TCI state activation / deactivation MAC-CE structure according to an embodiment of this disclosure is shown. The meaning of each field in the MAC CE and the configurable values ​​for each field are as follows.

[0474] Serving Cell ID: This field indicates the identifier of the serving cell to which the MAC CE is applied. The field is 5 bits long. If the indicated serving cell is configured as part of simultaneousCI-UpdateList1 or simultaneousCI-UpdateList2 as specified in TS 38.331[5], then this MAC CE applies to all serving cells configured in the set simultaneousCI-UpdateList1 or simultaneousCI-UpdateList2, respectively.

[0475] BWP ID: This field indicates the DL BWP applicable to MAC CE as the code point of the DCI bandwidth portion indicator field as specified in TS 38.212[9]. The BWP ID field is 2 bits long;

[0476] C_i: This field indicates whether an octet containing TCI state ID_i,2 exists. If this field is set to "1", an octet containing TCI state ID_i,2 exists. If this field is set to "0", an octet containing TCI state ID_i,2 does not exist.

[0477] TCI State ID_i,j: This field indicates the TCI state identified by the TCI-StateId as specified in TS 38.331[5], where i is the index of the code point in the DCI Transport Configuration Indication field as specified in TS 38.212[9], and TCI State ID_i,j represents the j-th TCI state indicated for the i-th code point in the DCI Transport Configuration Indication field. The TCI code point to which the TCI state is mapped is determined by its ordinal position among all TCI code points in the set having the TCI State ID_i,j field, i.e., the first TCI code point with TCI State ID0,1 and TCI State ID0,2 should be mapped to code point value 0, the second TCI code point with TCI State ID_1,1 and TCI State ID_1,2 should be mapped to code point value 1, and so on. TCI State ID_i,2 is optional based on the indication of the C_i field. The maximum number of active TCI code points is 8, and the maximum number of TCI states mapped to TCI code points is 2.

[0478] R: Reserved bit, set to "0".

[0479] refer to Figure 20If the value of field C_0 2005 is 1, then MAC-CE can also include field TCI state ID 0,2 2015 in addition to TCI state ID 0,1 fields 21-10. This means that TCI state IDs 0,1 and 0,2 are activated for the 0th code point of the TCI state field included in the DCI, and two TCI states can be indicated to the UE if the base station indicates the code point. If the value of field C_0 2005 is 0, then MAC-CE cannot include fields TCI state ID 0,2 21-15, and this means that one TCI state corresponding to TCI state ID 0,1 is activated for the 0th code point of the TCI state field included in the DCI.

[0480] The above configuration can be independent for each cell or each BWP. For example, the maximum number of active TCI states corresponding to a TCI code point in the PCell is 2, but the maximum number of active TCI states corresponding to a TCI code point in a specific SCell can be 1. In this case, it can be considered that NC-JT is configured in the PCell, but not in the SCell.

[0481] Differentiation method for multi-TRP PDSCH retransmission technology (TDM / FDM / SDM) based on a single DCI

[0482] Next, a method for distinguishing multi-TRP PDSCH retransmission techniques based on a single DCI is described. Different multi-TRP PDSCH retransmission techniques based on a single DCI (e.g., TDM, FDM, and SDM) can be indicated to the UE by the base station based on the value indicated by the DCI field and higher-layer signaling configuration. Table 24 below shows the method for distinguishing between single-TRP or multi-TRP based techniques indicated to the UE based on specific DCI field values ​​and higher-layer signaling configuration.

[0483] Table 24

[0484]

[0485] In Table 24, each column can be described as follows.

[0486] Number of TCI states (second column): This indicates the number of TCI states indicated by the TCI state field in the DCI, and can be 1 or 2.

[0487] Number of CDM Groups (Third Column): This indicates the number of different CDM groups for the DMRS port as indicated by the Antenna Port field in the DCI. This number can be 1, 2, or 3.

[0488] The repetitionNumber configuration and indication conditions (fourth column) can have three conditions: whether repetitionNumber is configured for all TDRA entries that can be indicated by the time-domain resource allocation field in DCI, and whether the TDRA entries actually indicated have repetitionNumber configuration.

[0489] Condition 1: At least one of all TDRA entries indicated by the Time Domain Resource Allocation field includes a configuration about repetitionNumber, and the TDRA entries indicated by the Time Domain Resource Allocation field in the DCI include a configuration about repetitionNumber greater than 1.

[0490] Condition 2: At least one of all TDRA entries indicated by the Time Domain Resource Allocation field includes configuration about repetitionNumber, and the TDRA entries indicated by the Time Domain Resource Allocation field in the DCI do not include configuration about repetitionNumber.

[0491] Condition 3: All TDRA entries that the Time Domain Resource Allocation field can indicate do not include configuration regarding repetitionNumber.

[0492] Related to repetitionScheme configuration (fifth column): This indicates whether a higher-level signaling repetitionScheme is configured. One of the higher-level signaling repetitionSchemes can be configured as "tdmSchemeA", "fdmSchemeA", or "fdmSchemeB".

[0493] Transmission technology indicated to the UE (sixth column): This indicates the single TRP or multiple TRP technology indicated by each combination shown in Table 24 (first column).

[0494] Single TRP: This indicates a PDSCH transmission based on a single TRP. If the pdsch-AggegationFactor in the higher-layer signaling PDSCH-config is configured for the UE, then a configured number of repeated PDSCH transmissions based on a single TRP can be scheduled to the UE. Otherwise, a single PDSCH transmission based on a single TRP can be scheduled to the UE.

[0495] Single TRP TDM Scheme B: This indicates PDSCH repetition transmission based on inter-slot time resource allocation within a single TRP. According to condition 1 related to repetitionNumber mentioned above, the UE repetitively transmits PDSCH in the time domain, with the number of repetition slots equal to the count of repetitionNumbers greater than 1 configured in the TDRA entry indicated by the time domain resource allocation field. For each PDSCH in a slot, the UE applies the same start symbol and the same symbol length as indicated by the TDRA entry, with the number of slots equal to the repetitionNumber count, and the same TCI state is applied to each PDSCH repetition transmission. This technique is similar to slot aggregation schemes because inter-slot PDSCH repetition is performed within the time resources; however, the difference lies in whether repetition transmission is indicated, which can be dynamically determined based on the time domain resource allocation field in the DCI.

[0496] Multiple TRP SDM: This refers to a PDSCH transmission scheme based on spatial resource partitioning using multiple TRPs. It's a method for receiving distributed layers from TRPs, not a repetitive transmission scheme, but it improves the reliability of PDSCH transmission because the increased number of layers allows for transmission at a lower code rate. The UE can apply the two TCI states indicated by the TCI state field in the DCI to two CDM groups indicated by the base station to receive PDSCH.

[0497] Multi-TRP FDM Scheme A: This refers to a PDSCH transmission scheme based on frequency resource allocation in Multi-TRP. This technique provides a single PDSCH transmission opportunity, thus avoiding repetitive transmissions like Multi-TRP SDM. However, it increases the amount of frequency resources to reduce the code rate, thereby achieving transmission with high reliability. Multi-TRP FDM Scheme A can apply two TCI states, indicated by the TCI state field in the DCI, to non-overlapping frequency resources. When the PRB bundle size is determined to be 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) number of RBs and the second TCI state to the remaining floor (N / 2) number of RBs to perform reception. Here, ceil (.) and floor (.) are operators indicating rounding up and down to one decimal place. If the PRB bundle size is determined to be 2 or 4, the UE applies the first TCI state to the even-numbered PRGs and the second TCI state to the odd-numbered PRGs to perform reception.

[0498] Multi-TRP FDM Scheme B: This means a PDSCH repetition transmission scheme based on multi-TRP frequency resource allocation, providing two PDSCH transmission opportunities to repeat PDSCH transmission in the corresponding opportunities. Similar to Multi-TRP FDM Scheme A, Multi-TRP FDM Scheme B can also apply two TCI states indicated by the TCI state field in the DCI to non-overlapping frequency resources. When the PRB bundle size is determined to be 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) number of RBs and the second TCI state to the remaining floor (N / 2) number of RBs to perform reception. Here, ceil(.) and floor(.) are operators indicating rounding up and down to one decimal place. If the PRB bundle size is determined to be 2 or 4, the UE applies the first TCI state to even-numbered PRGs and the second TCI state to odd-numbered PRGs to perform reception.

[0499] Multi-TRP TDM Scheme A: This means a PDSCH repetitive transmission scheme within a time slot based on multi-TRP time resource allocation. The UE can have two PDSCH transmission opportunities within a time slot, and the first reception opportunity can be determined based on the start symbol and symbol length of the PDSCH indicated by the time domain resource allocation field in the DCI. The start symbol of the second PDSCH reception opportunity can be the position obtained by applying the symbol offset of the higher-layer signaling StartingSymbolOffsetK to the last symbol of the first transmission opportunity, and the transmission opportunity can be determined to be the same length as the symbol length indicated by that position. If the higher-layer signaling StartingSymbolOffsetK is not configured, the symbol offset can be considered 0.

[0500] Multi-TRP TDM Scheme B: This means a PDSCH repetition transmission scheme based on multi-TRP time resource allocation between time slots. A UE can have one PDSCH transmission opportunity in a time slot and receive repetition transmissions based on the same PDSCH start symbol and symbol length during multiple time slots corresponding to the repetitionNumber count indicated by the time domain resource allocation field in the DCI. If repetitionNumber is 2, the UE can receive PDSCH repetition transmissions in the first and second time slots by applying a first TCI state and a second TCI state respectively. If repetitionNumber is greater than 2, the UE can use different TCI state application schemes depending on which value the higher-layer signaling tciMapping is configured to. If tciMapping is configured as cyclicMapping, the UE applies the first and second TCI states to the first and second PDSCH transmission opportunities respectively, and also applies the same TCI state application method to the remaining PDSCH transmission opportunities. If tciMapping is configured as sequentialMapping, the UE applies the first TCI state to the first and second PDSCH transmission times, applies the second TCI state to the third and fourth PDSCH transmission times respectively, and applies the TCI state application method to the remaining PDSCH transmission times in the same manner.

[0501] Related to DMRS

[0502] Next, the antenna port field indications included in DCI format 1_1 and DCI format 1_2 as defined in Table 7 above will be described. The antenna port fields in DCI formats 1_1 and 1_2 can be represented by 4, 5, or 6 bits, and can be indicated by Tables 25-1 to 25-8 below.

[0503] Table 25-1 Antenna Ports (1000+DMRS Ports), dmrs-Type=1, maxLength=1

[0504]

[0505] Table 25-2 Antenna Ports (1000+DMRS Ports), dmrs-Type=1, maxLength=1

[0506]

[0507] Table 25-3 Antenna Ports (1000+DMRS Ports), dmrs-type=1, maxLength=2

[0508]

[0509] Table 25-4 Antenna Ports (1000+DMRS Ports), dmrs-type=1, maxLength=2

[0510]

[0511] Table 25-5: Antenna Ports (1000+DMRS Ports), dmrs-Type=2, maxLength=1

[0512]

[0513] Table 25-6: Antenna Ports (1000+DMRS Ports), dmrs-Type=2, maxLength=1

[0514]

[0515] Table 25-7: Antenna Ports (1000+DMRS Ports), dmrs-Type=2, maxLength=2

[0516]

[0517]

[0518] Table 25-8: Antenna Ports (1000+DMRS Ports), dmrs-Type=2, maxLength=2

[0519]

[0520]

[0521] Tables 25-1 and 25-2 are used when dmrs-type is indicated as 1 and maxLength is indicated as 1; Tables 25-3 and 25-4 are used when dmrs-type is equal to 1 and maxLength is equal to 2; Tables 25-5 and 25-6 show the DMRS ports used when dmrs-type is equal to 2 and maxLength is equal to 1; and Tables 25-7 and 25-8 show the DMRS ports used when dmrs-type is equal to 2 and maxLength is equal to 2.

[0522] According to an embodiment, if the UE has received a MAC-CE indicating two TCI states for activating at least one code point indicating the TCI state field in the DCI, the DMRS port can indicate this to the UE using Tables 25-2, 25-4, 25-6, and 25-8; otherwise, the DMRS port can indicate this to the UE using Tables 25-1, 25-3, 25-5, and 25-7. If the code point indicating two TCI states is indicated to the UE via the TCI state field, then for the purpose of NC-JT scheduling in Tables 25-2, 25-4, 25-6, and 25-8, entries indicating DMRS ports 1000, 1002, and 1003 can be indicated to the UE, and these entries can be entry #12 in Table 25-2, entry #31 in Table 25-4, entry #24 in Table 25-6, and entry #58 in Table 25-8.

[0523] According to an embodiment, regarding DCI format 1_1, if both higher-layer signaling dmrs-DownlinkForPDSCH-MappingTypeA and dmrs-DownlinkForPDSCH-MappingTypeB are configured for the UE, the bit length of the antenna port field in DCI format 1_1 can be determined as max{xA, xB}, where xA and xB can respectively indicate the bit length of the antenna port field determined by dmrs-DownlinkForPDSCH-MappingTypeA and dmrs-DownlinkForPDSCH-MappingTypeB. If the PDSCH mapping type corresponding to the smaller value of xA and xB is scheduled, each of the MSB bits, which is equal to |xA-xB|, can be allocated 0 bits and then transmitted.

[0524] According to the embodiment, regarding DCI format 1_2, if the higher-layer signaling antennaPortsFieldPresenceDCI-1-2 is not configured for the UE, then the antenna port field may not exist in DCI format 1_2. That is, the length of the antenna port field is 0 bits, and the UE can determine the DMRS port by assuming the 0th entry in Tables 25-1, 25-3, 25-5, and 25-7. If the higher-layer signaling antennaPortsFieldPresenceDCI-1-2 is configured for the UE, then the bit length of the antenna port field in DCI format 1_2 can be determined similarly to the above situation for DCI format 1_1. If both higher-layer signaling dmrs-DownlinkForPDSCH-MappingTypeA-DCI-1-2 and dmrs-DownlinkForPDSCH-MappingTypeB-DCI-1-2 are configured for the UE, the bit length of the antenna port field in DCI format 1_2 can be determined as max{xA, xB}, and xA and xB can respectively indicate the bit length of the antenna port field determined by dmrs-DownlinkForPDSCH-MappingTypeA-DCI-1-2 and dmrs-DownlinkForPDSCH-MappingTypeB-DCI-1-2. If the PDSCH mapping type corresponding to the smaller value of xA and xB is scheduled, each of the MSB bits, which is equal to |xA-xB|, can be assigned 0 bits and then transmitted.

[0525] According to the embodiment, the numbers 1, 2, and 3, indicating the number of DMRS CDM groups without data in Tables 25-1 to 25-8, indicate CDM groups {0}, {0,1}, and {0,1,2}, respectively. The DMRS ports are listed sequentially as the indices of the ports used. Antenna ports can be indicated by DMRS port + 1000. The CDM groups of the DMRS are connected to the antenna ports, and the method for generating the DMRS sequence is shown in Tables 26-1 and 26-2. Table 26-1 shows the parameters for the case using dmrs-type=1, and Table 26-2 shows the parameters for the case using dmrs-type=2.

[0526] Table 26-1: Parameters for PDSCH DM-RS dmrs-type=1

[0527]

[0528] Table 26-2: Parameters for PDSCH DM-RS dmrs-type=2

[0529]

[0530] According to the embodiment, the DMRS sequence for each parameter is determined by the following equation 3-1. In equation 3-1, p represents the DMRS port, k represents the subcarrier index, and l represents the OFDM symbol index. Let represent the subcarrier spacing, and wf(k') and wt(l') represent the frequency domain orthogonal coverage code (FD-OCC) coefficients and time domain orthogonal coverage code (TD-OCC) coefficients based on the values ​​of k' and l', respectively. The interval between CDM groups is represented by the number of subcarriers. In Equation 3-1, It is a scaling factor indicating the ratio between the energy per RE (EPRE) of the PDSCH and the EPRE of the DMRS, and can be used to... To calculate, and The values ​​can be 0 dB, -3 dB, and -4.77 dB, depending on the number of CDM groups 1, 2, and 3.

[0531] …Equation 3-1

[0532]

[0533]

[0534]

[0535]

[0536] According to an embodiment, when using DMRS type 1, if a single codeword is scheduled and entries #2, #9, #10, #11, and #30 are indicated to the UE using Tables 25-1 and 25-3; if a single codeword is scheduled and entries #2, #9, #10, #11, and #12 are indicated to it using Table 25-2; if a single codeword is scheduled and entries #2, #9, #10, #11, #30, and #31 are indicated to it using Table 25-4; or if two codewords are scheduled, then the UE can consider the scheduling to be single-user MIMO scheduling. That is, the UE can assume that different UEs are not scheduled to all remaining orthogonal DMRS ports other than the DMRS ports allocated to the scheduled PDSCH, and can not anticipate multi-user MIMO (MU-MIMO) scheduling. In this case, the UE does not assume that different UEs are co-scheduled, and can not perform multi-user MIMO reception operations such as canceling, zeroing, or whitening multi-user interference.

[0537] According to an embodiment, when using DMRS type 2, if a single codeword is scheduled and entries #2, #10, and #23 are indicated to the UE using Tables 25-5 and 25-7; if a single codeword is scheduled and entries #2, #10, #23, and #24 are indicated to it using Table 25-6; if a single codeword is scheduled and entries #2, #10, #23, and #58 are indicated to it using Table 25-8; or if two codewords are scheduled, the UE can consider the scheduling to be single-user MIMO scheduling. That is, the UE can assume that different UEs are not scheduled to all remaining orthogonal DMRS ports other than the DMRS ports allocated to the scheduled PDSCH, and can not anticipate multi-user MIMO scheduling. In this case, the UE does not assume that different UEs are co-scheduled and can not perform multi-user MIMO reception operations such as canceling, zeroing, or whitening multi-user interference.

[0538] According to the embodiment, the UE may not expect to configure one or more additional DMRS symbols via the higher-layer signaling dmrs-AdditionalPosition while configuring the maximum number of front-loaded DMRS symbols to len2 via the higher-layer signaling maxLength.

[0539] According to the embodiment, the UE may not expect that the actual number of preloaded DMRS, the actual number of attached DMRS symbols, the DMRS symbol locations, and the DMRS type configuration will be different for all UEs undergoing multi-user MIMO scheduling.

[0540] According to an embodiment, when the UE has a PRG size of 2 or 4, the UE may not anticipate a mismatch in frequency resource allocation in the PRG cell grids of different UEs that are co-scheduled using different orthogonal DMRS ports in the same CDM group as the DMRS port indicated to the UE.

[0541] According to the embodiment, in the case of PDSCH scheduled by DCI formats 1_1 and 1_2, the UE may assume that the CDM groups indicated by the "Number of DMRS CDM Groups without Data" column in Tables 25-1 to 25-8 may include DMRS ports allocated to different UEs that can be co-scheduled by a multi-user MIMO scheme, and may not be used for data transmission by the UE. It can also be understood that the values ​​1, 2 and 3 in the "Number of DMRS CDM Groups without Data" column in Tables 25-1 to 25-8 may mean that the indexes of the CDM groups corresponding to the above meanings correspond to CDM groups 0, {0,1} and {0,1,2}, respectively.

[0542] According to an embodiment, if a higher-layer signaling dmrs-FD-OCC-disableForRank1PDSCH is configured for a UE and a DMRS port is assigned to a UE for PDSCH scheduling, the UE may not expect different UEs to be assigned to DMRS ports using different FD-OCCs in different orthogonal DMRS ports belonging to the same CDM group as an assigned DMRS port.

[0543] Next, the antenna port field indications included in DCI formats 0_1 and 0_2 as defined in Table 5 above will be described. The antenna port fields in DCI formats 0_1 and 0_2 can be represented by 3, 4, or 5 bits, and can be indicated by Tables 25-9 to 25-24 below.

[0544] Table 25-9 Antenna Port, Transform Precoder Disabled, dmrs-Type=1, maxLength=1, Rank=

[0545] Table 25-10 Antenna Port, Transform Precoder Disabled, dmrs-Type=1, maxLength=1, Rank=2

[0546]

[0547] Table 25-11 Antenna Port, Transform Precoder Disabled, dmrs-Type=1, maxLength=1, Rank=3

[0548]

[0549] Table 25-12 Antenna Ports, Transform Precoder Disabled, dmrs-Type=1, maxLength=1, Rank=4

[0550]

[0551] Table 25-13 Antenna Port, Transform Precoder Disabled, dmrs-Type=1, maxLength=2, Rank=1

[0552]

[0553] Table 25-14 Antenna Ports, Transform Precoder Disabled, dmrs-Type=1, maxLength=2, Rank=2

[0554]

[0555] Table 25-15 Antenna Port, Transform Precoder Disabled, dmrs-Type=1, maxLength=2, Rank=3

[0556]

[0557] Table 25-16 Antenna Port, Transform Precoder Disabled, dmrs-Type=1, maxLength=2, Rank=4

[0558]

[0559] Table 25-17 Antenna Port, Transform Precoder Disabled, dmrs-Type=2, maxLength=1, Rank=1

[0560]

[0561] Table 25-18 Antenna Port, Transform Precoder Disabled, dmrs-Type=2, maxLength=1, Rank=2

[0562]

[0563] Table 25-19 Antenna Port, Transform Precoder Disabled, dmrs-Type=2, maxLength=1, Rank=3

[0564]

[0565] Table 25-20 Antenna Ports: Transform Precoder disabled, dmrs-Type=2, maxLength=1, rank=4

[0566]

[0567] Table 25-21 Antenna Port, Transform Precoder Disabled, dmrs-Type=2, maxLength=2, Rank=1

[0568]

[0569] Table 25-22 Antenna Port, Transform Precoder Disabled, dmrs-Type=2, maxLength=2, Rank=2

[0570]

[0571] Table 25-23 Antenna Port, Transform Precoder Disabled, dmrs-Type=2, maxLength=2, Rank=3

[0572]

[0573] Table 25-24 Antenna Port, Transform Precoder Disabled, dmrs-Type=2, maxLength=2, Rank=4

[0574]

[0575] According to the embodiment, Tables 25-9 to 25-12 are tables used when dmrs-type is indicated as 1 and maxLength is indicated as 1, Tables 25-13 to 25-16 are tables used when dmrs-type is indicated as 1 and maxLength is indicated as 2, Tables 25-17 to 25-20 show the DMRS ports used when dmrs-type is equal to 2 and maxLength is equal to 1, and Tables 25-21 to 25-24 show the DMRS ports used when dmrs-type is equal to 2 and maxLength is equal to 2.

[0576] According to an embodiment, regarding DCI format 0_1, if both higher-layer signaling dmrs-UplinkForPUSCH-MappingTypeA and dmrs-UplinkForPUSCH-MappingTypeB are configured for the UE, the bit length of the antenna port field in DCI format 0_1 ​​can be determined as max{xA, xB}, where xA and xB can respectively indicate the bit length of the antenna port field determined by dmrs-UplinkForPUSCH-MappingTypeA and dmrs-UplinkForPUSCH-MappingTypeB. If the PUSCH mapping type corresponding to the smaller value of xA and xB is scheduled, each of the MSB bits, which is equal to |xA-xB|, can be assigned 0 bits and then transmitted.

[0577] According to the embodiment, regarding DCI format 0_2, if the higher-layer signaling antennaPortsFieldPresenceDCI-0-2 is not configured for the UE, then the antenna port field may not exist in DCI format 0_2. That is, in this case, the length of the antenna port field is 0 bits, and the UE can determine the DMRS port by assuming the 0th entry in Tables 25-9 to 25-24. If the higher-layer signaling antennaPortsFieldPresenceDCI-0-2 is configured for the UE, the bit length of the antenna port field in DCI format 0_2 can be determined in a manner similar to that described above for DCI format 0_1. If both higher-layer signaling dmrs-UplinkForPUSCH-MappingTypeA-DCI-0-2 and dmrs-UplinkForPUSCH-MappingTypeB-DCI-0-2 are configured for the UE, the bit length of the antenna port field in DCI format 0_2 can be determined as max{xA, xB}, and xA and xB can respectively indicate the bit length of the antenna port field determined by dmrs-UplinkForPUSCH-MappingTypeA-DCI-0-2 and dmrs-UplinkForPUSCH-MappingTypeB-DCI-0-2. If the PDSCH mapping type corresponding to the smaller value of xA and xB is scheduled, each of the MSB bits, as many as |xA-xB|, can be assigned 0 bits and then transmitted.

[0578] According to the embodiment, the numbers 1, 2, and 3, indicating the number of DMRS CDM groups without data in Tables 25-9 to 25-24, indicate CDM groups {0}, {0,1}, and {0,1,2}, respectively. The DMRS ports are shown in sequence as the indices of the ports used. The antenna port can be indicated by DMRS port +1000. The CDM groups of the DMRS are connected to the antenna ports, and the method for generating the DMRS sequence is shown in Tables 26-1a and 26-2a. Table 26-1a shows the parameters for the case where dmrs-type=1 is used, and Table 26-2a shows the parameters for the case where dmrs-type=2 is used.

[0579] Table 26-1a: Parameters for PUSCH DM-RS dmrs-type=1

[0580]

[0581] Table 26-2a: Parameters for PUSCH DM-RS dmrs-type=2

[0582]

[0583] According to an embodiment, the DMRS sequence for each parameter is determined by the following equation 3-1. In equation 3-1, This indicates the DMRS port, k represents the subcarrier index, and l represents the OFDM symbol index. Let represent the subcarrier spacing, and wf(k') and wt(l') represent the frequency domain orthogonal coverage code (FD-OCC) coefficients and time domain orthogonal coverage code (TD-OCC) coefficients based on the values ​​of k' and l', respectively. The interval between CDM groups is represented by the number of subcarriers. In Equation 3-2, It is a scaling factor indicating the ratio between the energy per RE (EPRE) of PUSCH and the EPRE of DMRS, and can be used to... To calculate, and The values ​​can be 0 dB, -3 dB, and -4.77 dB, depending on the number of CDM groups 1, 2, and 3.

[0584] …Equation 3-2

[0585]

[0586]

[0587]

[0588]

[0589]

[0590]

[0591] According to the embodiment, if frequency hopping is not used, the UE may need to assume that the higher-layer signaling dmrs-AdditionalPosition is configured as "pos2" and that at most two additional DMRS symbols are available for PUSCH transmission. If frequency hopping is used, the UE may need to assume that the higher-layer signaling dmrs-AdditionalPosition is configured as "pos1" and that at most one additional DMRS symbol is available for PUSCH transmission.

[0592] According to the embodiment, in the case of PUSCH scheduled by DCI formats 0_1 and 0_2, the UE may assume that the CDM groups indicated by the "Number of DMRS CDM Groups without Data" column in Tables 25-9 to 25-24 may include DMRS ports allocated to different UEs that can be co-scheduled by a multi-user MIMO scheme, and may not be used for data transmission by the UE. It can also be understood that the values ​​1, 2, and 3 in the "Number of DMRS CDM Groups without Data" column in Tables 25-9 to 25-24 may mean that the indexes of the CDM groups corresponding to the above meanings correspond to CDM groups 0, {0,1}, and {0,1,2}, respectively.

[0593] <First Embodiment: Method for Supporting Enhanced DMRS Types 1 and 2 with an Increased Number of Orthogonal Ports>

[0594] As an embodiment of this disclosure, a method for supporting an increased number of orthogonal ports in enhanced DMRS types 1 and 2 is described. This embodiment can be combined with other embodiments.

[0595] The 5G evolution standard can support enhanced DMRS Type 1 and DMRS Type 2, which support an increased number of orthogonal ports while maintaining the same RE usage and overhead as all uplink and downlink DMRS Type 1 and DMRS Type 2 supported in the initial 5G standard. In the case of traditional DMRS Type 1, a maximum of four and eight orthogonal DMRS ports can be supported if the number of preloaded symbols is 1 and 2, respectively. In the case of DMRS Type 2, a maximum of six and twelve orthogonal DMRS ports can be supported if the number of preloaded symbols is 1 and 2, respectively. Referring to these supported features, in the case of enhanced DMRS Type 1, a maximum of eight and sixteen orthogonal DMRS ports can be supported if the number of preloaded symbols is 1 and 2, respectively. In the case of enhanced DMRS Type 2, a maximum of twelve and twenty-four orthogonal DMRS ports can be supported if the number of preloaded symbols is 1 and 2, respectively. In the following text, the new DMRS types that support an increased number of orthogonal ports, as described above, may be named one of "Enhanced DMRS Types 1 and 2", "New DMRS Types 1 and 2", "New DMRS Types 1 and 2", "DMRS Types 1-1 and 2-1", or "DMRS Types 3 and 4", and may be referred to by other similar extended names that imply enhanced functionality compared to the traditional DMRS Types 1 and 2. The following items are primarily described for downlink, but can be similarly applied to uplink DMRS support.

[0596] According to an embodiment, if the UE supports Enhanced DMRS Type 1 and 2, the UE can report its UE capabilities supporting Enhanced DMRS Type 1 and 2 to the base station. The UE capability report can be sent to the base station per frequency band, and more specifically, per feature set (FS) or per feature set per component carrier (FSPC). Furthermore, the UE capability report can be different for each FR, or it can be limited to FR1. Moreover, as mentioned above, the UE capability report can include the meaning that "in the case of Enhanced DMRS Type 1, if the number of preloaded symbols is 1 and 2, up to eight and sixteen orthogonal DMRS ports can be supported respectively, and in the case of Enhanced DMRS Type 2, if the number of preloaded symbols is 1 and 2, up to twelve and twenty-four orthogonal DMRS ports can be supported respectively." The UE can perform the reporting through common UE capabilities for Enhanced DMRS Type 1 and 2. In this case, the UE can report whether it supports only Enhanced DMRS Type 1, only Enhanced DMRS Type 2, or both. In addition, the UE can also report whether it supports each of the enhanced DMRS types 1 and 2 through individual UE capabilities.

[0597] According to the embodiment, if the UE supports dynamic handover between enhanced DMRS types and legacy DMRS types, the UE can report this functionality through UE capabilities. Dynamic handover between enhanced and legacy types can mean that the DMRS type configured via higher-layer signaling can be changed via MAC-CE, the selection between enhanced and legacy types can be made via DCI, or both. If the UE reports whether it supports enhanced DMRS types 1 and 2 through a common UE capability, the UE can report whether it supports dynamic handover for DMRS types 1 and 2 through a single UE capability report, while also reporting whether the UE only supports dynamic handover between DMRS type 1 and enhanced DMRS type 1, whether the UE only supports dynamic handover between DMRS type 2 and enhanced DMRS type 2, or whether the UE supports dynamic handover between enhanced and legacy types for both types. Conversely, if the UE reports whether it supports enhanced DMRS types 1 and 2 through a common UE capability or a separate UE capability, the UE can report dynamic handover between legacy and enhanced types through separate UE capabilities for each type.

[0598] According to an embodiment, furthermore, when the UE operates in Enhanced DMRS Type 1 or 2, if the UE supports both Traditional DMRS Type 1 or 2 and multi-user MIMO scheduling, the UE can report this functionality through its UE capabilities. Multi-user MIMO scheduling can indicate coordinated scheduling between Traditional DMRS Type 1 and Enhanced DMRS Type 1, or between Traditional DMRS Type 2 and Enhanced DMRS Type 2. Similar to the above description, UE capabilities related to the possibility of coordinated scheduling between Traditional and Enhanced types are reported as common UE capabilities, whereby the UE can report only that coordinated scheduling between Traditional Type 1 and Enhanced Type 1 is possible, only that coordinated scheduling between Traditional Type 2 and Enhanced Type 2 is possible, or report that coordinated scheduling between Traditional and Enhanced types is possible for both Type 1 and Type 2. Alternatively, the UE can perform reporting through separate UE capabilities for each type.

[0599] For UEs that have already reported their capabilities, the base station can configure enhanced DMRS type 1 and 2 schemes for the UE via higher-layer signaling using the following methods.

[0600] [High-level configuration method 1] For example, the supported enhanced DMRS types can be configured for the UE via high-level signaling DMRS-DownlinkConfig.

[0601] [High-layer configuration method 1-1] Similar to the high-layer signaling dmrs-Type-r18 used to determine the traditional type of high-layer signaling, it can be configured and can also be used to define enhanced DMRS types other than DMRS type 1 or 2. A new RRC IE, also called dmrs-Type-r18 in addition to dmrs-Type, can be configured for the UE in the high-layer signaling DMRS-DownlinkConfig. Through dmrs-Type-r18, one of DMRS type 1 or 2, or enhanced DMRS type 1 or 2, can be determined, or one of enhanced DMRS type 1 or 2 can be determined.

[0602] For example, as shown in Table 26-3 below, if dmrs-Type-r18 is configured, it can determine either DMRS type 2 or enhanced DMRS type 1 or 2, and the existing dmrs-Type can be ignored. If dmrs-Type-r18 is not configured, the DMRS type can be determined according to the dmrs-Type configuration scheme.

[0603] As another example, if dmrs-Type-r18 is configured, either Enhanced DMRS Type 1 or 2 can be determined, and the existing dmrs-Type can be ignored. If dmrs-Type-r18 is not configured, the dmrs-Type can be determined based on the DMRS type configuration scheme.

[0604] If the above-described high-level configuration method is used, the UE can use only one of the traditional scheme (e.g., DMRS type 1 or 2) and the enhanced scheme (e.g., enhanced DMRS type 1 or 2) for each of PDSCH mapping types A or B, and this can be a high-level configuration scheme in which dynamic handover between the traditional and enhanced schemes is not possible or does not consider dynamic handover. The name dmrs-Type-r18 as the name of the RRC IE is merely an example and may differ from the actual name of the RRC IE.

[0605] Table 26-3

[0606]

[0607] [Higher-layer configuration method 1-2] While using the conventional meaning of the existing dmrs-Type used to determine one of DMRS Type 1 and 2, a new RRC IE can be configured to indicate whether Enhanced DMRS Type 1 or 2 is available. As shown in Table 26-4 below, if the base station does not configure a higher-layer signaling dmrs-Type for the UE and does not configure enhanced-Dmrs-Type-r18 for it, the UE can support the conventional scheme for DMRS Type 1. Alternatively, if no dmrs-Type is configured for the UE and enhanced-Dmrs-Type-r18 is configured to be enabled, this may mean that the UE can support the enhanced scheme for DMRS Type 1. In this case, if the UE supports dynamic handover between the conventional and enhanced types, and enhanced-Dmrs-Type-r18 is configured for the UE, the UE can perform dynamic handover without additional higher-layer signaling, or the base station can configure whether to perform dynamic handover for the UE via dynamicSwitchType as additional higher-layer signaling.

[0608] Table 26-4

[0609]

[0610] [Higher-layer configuration method 2] The UE can support enhanced DMRS types without using the higher-layer signaling DMRS-DownlinkConfig, and can configure the supported enhanced DMRS types for the UE separately for higher-layer signaling via the new RRC IE in PDSCH-Config. As shown in Table 26-5 below, if the base station does not configure the higher-layer signaling enhanced-Dmrs-Type-r18 for the UE, the UE can determine the DMRS type based on the existing DMRS-DownlinkConfig configuration. If the base station configures the higher-layer signaling enhanced-Dmrs-Type-r18 for the UE, the UE can use the enhancement scheme for the DMRS type determined according to the existing DMRS-DownlinkConfig configuration. In this case, if the UE supports dynamic switching between the traditional type and the enhanced type, and enhanced-Dmrs-Type-r18 is configured for the UE, the UE can perform dynamic switching without additional higher-layer signaling, or the base station can configure whether to perform dynamic switching for the UE via dynamicSwitchType as additional higher-layer signaling.

[0611] Table 26-5

[0612]

[0613] Enhanced DMRS Type 1 Support Method

[0614] As another embodiment of the method supporting the aforementioned Enhanced DMRS Type 1, the UE can determine the time and frequency resource mapping of the DMRS RE and the FD-OCC and TD-OCC coefficients used for mapping when using Enhanced DMRS Type 1, based on Equation 4-1 and Table 26-1-1 below. The following items are created based on the downlink data channel demodulation signal (PDSCHDMRS) and can be similarly applied to the uplink data channel demodulation signal (PUSCHDMRS), and the DMRS port number can be 0 to 15 instead of 1000 to 1015, as shown in the first column of Table 26-1-1. In Equation 4-1 below, It can indicate the number of layers in PDSCH or PUSCH.

[0615] …Equation 4-1

[0616] (For Enhanced DMRS Type 1)

[0617]

[0618]

[0619]

[0620]

[0621] Table 26-1-1 Parameters for [Enhanced DMRS Type 1 Support Method]

[0622]

[0623] According to the embodiment, the [Enhanced DMRS Type 1 Support Method] based on Equation 4-1 and Table 26-1-1 can use a total of two CDM groups. In the case of one preloaded DMRS symbol, each CDM group can include four DMRS ports, thus supporting up to eight orthogonal DMRS ports, and in the case of two preloaded DMRS symbols, each CDM group can include eight DMRS ports, thus supporting a total of 16 orthogonal DMRS ports.

[0624] As described above, the number of DMRS ports in each CDM group has been increased, and its OCC length has been increased to 4, while maintaining 2 as the number of CDM groups for traditional DMRS type 1. Therefore, the scheduling of PDSCH to be sent with DMRS can be done in units of two RBs, and DMRS can be mapped to the same RE position as the RE position for traditional DMRS type 1.

[0625] However, in the traditional DMRS type 1, assuming that two REs separated by two REs (e.g., RE#0 and RE#2) have the same channel, an OCC is applied to these two REs to distinguish the orthogonal ports, and in the case of a preloaded DMRS symbol, each port uses a total of six REs in one RB and uses three OCCs of length 2.

[0626] If the [Enhanced DMRS Type 1 Support Method] is used, with one preloaded DMRS symbol, each port uses a total of 12 REs in two RBs, and the total of four orthogonal antenna ports can be distinguished using an OCC of length 4 applied to four adjacent REs. The 4-length OCC is applied to the four REs, and the four REs can be spaced two REs apart from each other. That is, by treating four REs with relative RE positions 0, 2, 4, and 6 as the same channel, an OCC needs to be applied to all four REs, thus potentially reducing channel estimation performance compared to conventional DMRS Type 1. Therefore, this Enhanced DMRS Type 1 can be used for multi-user MIMO in channels with low-frequency selectivity.

[0627] In Table 26-1-1 above, ports 1000 to 1015 of the OCC with a length of 4 can be identified. The values ​​are provided to ensure orthogonality between all ports, and the values ​​in the table above correspond only to examples, not excluding other values. In Equation 4-1, It is a scaling factor indicating the ratio between the energy per RE (EPRE) of the PDSCH and the EPRE of the DMRS, and can be used to... To calculate, and The value can be 0 dB and -3 dB depending on the number of CDM groups 1 and 2.

[0628] Enhanced DMRS Type 2 Support Method

[0629] Based on Equation 4-2 and Table 26-2-1 below, the time and frequency resource mapping of DMRSRE, as well as the FD-OCC and TD-OCC coefficients used for mapping, can be determined when using Enhanced DMRS Type 2. The following items are created based on the downlink data channel demodulation signal (PDSCH DMRS) and can be similarly applied to the uplink data channel demodulation signal (PUSCH DMRS), and the DMRS port number can be 0 to 23 instead of 1000 to 1023, as shown in the first column of Table 26-2-1. In Equation 4-2 below, It can indicate the number of layers in PDSCH or PUSCH.

[0630] …Equation 4-2

[0631] (For enhanced DMRS type 2, k'=0,1)

[0632] (For enhanced DMRS type 2, k'=2,3)

[0633]

[0634]

[0635]

[0636]

[0637] Table 26-2-1: Parameters for [Enhanced DMRS Type 2 Support Method]

[0638]

[0639] According to the embodiment, the [Enhanced DMRS Type 2 Support Method] based on Equation 4-2 and Table 26-2-1 can use a total of three CDM groups. With one preloaded DMRS symbol, each CDM group can include four DMRS ports, thus supporting a total of 12 orthogonal DMRS ports. With two preloaded DMRS symbols, each CDM group can include eight DMRS ports, thus supporting a total of 24 orthogonal DMRS ports.

[0640] As described above, while maintaining the number of CDM groups, the number of DMRS ports in each CDM group has been increased. Therefore, the scheduling of PDSCH sent along with DMRS can be maintained in the same manner as existing scheduling, on a per-RB basis, and DMRS can be mapped to the same RE location as conventional DMRS Type 2.

[0641] However, in the traditional DMRS Type 2, under the assumption that two consecutive REs belong to the same channel, OCC is applied to two REs to distinguish orthogonal ports, and in the case of a preloaded DMRS symbol, each port uses a total of four REs in one RB and uses two OCCs of length 2.

[0642] If based on the [Enhanced DMRS Type 2 Support Method], with a preloaded DMRS symbol, each port uses a total of four REs in one RB, and a total of four orthogonal ports can be distinguished using an OCC of length 4. That is, applying a length 4 OCC to two consecutive RE sets separated by six REs means that the OCC needs to be applied by treating the four REs with relative RE positions 0, 1, 6, and 7 as the same channel. Therefore, channel estimation performance may be degraded compared to conventional DMRS Type 2. Thus, this Enhanced DMRS Type 2 can be used for multi-user MIMO in channels with low-frequency selectivity.

[0643] In the above equation 4-2, It is a scaling factor indicating the ratio between the energy per RE (EPRE) of the PDSCH and the EPRE of the DMRS, and can be used to... To calculate, and The values ​​can be 0 dB, -3 dB, and -4.77 dB, depending on the number of CDM groups 1, 2, and 3.

[0644] Regarding the aforementioned [Enhanced DMRS Type 1 Support Method] and [Enhanced DMRS Type 2 Support Method], the UE can report to the base station UE capabilities indicating the feasibility of each support method. UE capabilities may be valid only for FR1, or for both FR1 and FR2. UE capabilities may include the following meaning: "As the maximum number of supported ports, for Enhanced DMRS Type 1, 8 ports are possible when using one preloaded DMRS symbol, and 16 ports are possible when using two preloaded DMRS symbols; and for Enhanced DMRS Type 2, 12 ports are possible when using one preloaded DMRS symbol, and 24 ports are possible when using two preloaded DMRS symbols." After receiving the UE capabilities, the base station can configure the corresponding higher-layer signaling, which can be one of the aforementioned higher-layer signaling configuration methods, or it can be independent higher-layer signaling.

[0645] The base station and UE can support at least one of the [Enhanced DMRS Type 1 Support Method] or [Enhanced DMRS Type 2 Support Method] through a configuration method via higher-layer signaling, an indication method based on L1 signaling, a combination of higher-layer signaling and L1 signaling, or a method fixed in the specification.

[0646] <Second Embodiment: A method for further supporting enhanced DMRS Type 1 and 2 methods with an increased number of orthogonal ports>

[0647] As an embodiment of this disclosure, an additional method for supporting enhanced DMRS types 1 and 2, which support an increased number of orthogonal ports, is described. This embodiment can be combined with other embodiments.

[0648] As an additional parameter to the above-described [Enhanced DMRS Type 1 Support Method], Table 26-6-1 below allows for the definition of relationships related to the availability of the CDM group including the DMRS port, or the FD-OCC index or TD-OCC index, depending on which DMRS port is used. Similarly, as an additional parameter to the above-described [Enhanced DMRS Type 2 Support Method], Table 26-6-2 below allows for the definition of relationships related to the availability of the CDM group including the DMRS port, or the FD-OCC index or TD-OCC index, depending on which DMRS port is used. Tables 26-6-3 and 26-6-4 can define the FD-OCC indices available in Tables 26-6-1 and 26-6-2, while Tables 26-6-5 and 26-6-6 can define the TD-OCC indices available in Tables 26-6-1 and 26-6-2. In Tables 26-6-1 and 26-6-2, p indicates the DMRS port. p is used in the case of PDSCH, and in the case of PUSCH, the value obtained by subtracting 1000 from p can be used.

[0649] In Table 26-6-1 below, DMRS ports 1000 to 1003 and 1008 to 1011 can be used for single or dual preloaded DMRS symbols, while DMRS ports 1004 to 1007 and 1012 to 1015 can be used for dual preloaded DMRS symbols.

[0650] In Table 26-6-2 below, DMRS ports 1000 to 1005 and 1012 to 1017 can be used for single or dual preloaded DMRS symbols, while DMRS ports 1006 to 1011 and 1018 to 1023 can be used for dual preloaded DMRS symbols.

[0651] The J used in Tables 26-6-3 to 26-6-6 below is an imaginary number and can indicate sqrt(-1).

[0652] To support the aforementioned [Enhanced DMRS Type 1 Support Method] and [Enhanced DMRS Type 2 Support Method], Tables 26-6-1 and 26-6-2 below can be used respectively, and at least one of Tables 26-6-3 to 26-6-6 below can be used to determine the indices of FD-OCC and TD-OCC to be used in Tables 26-6-1 and 26-6-2. The above determination can be configured by the base station for the UE via higher-layer signaling, dynamically indicated via L1 signaling, notified via a combination of higher-layer and L1 signaling, or defined in the specification.

[0653] According to the embodiment, when the base station schedules PDSCH or PUSCH, the UE can determine a type of FD-OCC and TD-OCC from Tables 26-6-3 to 26-6-6 below, and apply them together to PDSCH and PUSCH scheduling.

[0654] According to an embodiment, when the base station schedules PDSCH and PUSCH, the UE can determine one type of FD-OCC and TD-OCC from Tables 26-6-3 to 26-6-6 below and apply it to PDSCH scheduling, and can determine another type of FD-OCC and TD-OCC from Tables 26-6-3 to 26-6-6 below and apply it to PUSCH scheduling. For example, when the base station schedules PDSCH, the UE can use the FD-OCC index and the values ​​in Table 26-6-3 for the aforementioned enhanced DMRS types 1 and 2, and when the base station schedules PUSCH, the UE can use the FD-OCC index and the values ​​in Table 26-6-4 for the aforementioned enhanced DMRS types 1 and 2. However, this is only an example, and various embodiments of this disclosure do not exclude any combination such as the UE using the same FD-OCC for PDSCH and PUSCH and using different TD-OCCs for PDSCH and PUSCH.

[0655] Tables 26-6-1 and 26-6-2 below are based on PDSCH DMRS and can be similarly applied to PUSCH DMRS. In this case, the DMRS port number can be 0 to 15 instead of 1000 to 1015 as shown in the first column of Table 26-6-1, and can be 0 to 23 instead of 1000 to 1023 as shown in the first column of Table 26-6-2.

[0656] Table 26-6-6 below is based on PUSCH DMRS and can be similarly applied to PDSCH DMRS. In this case, for Enhanced DMRS Type 1, the DMRS port numbers can be 100 to 1007 and 1008 to 1015, instead of 0 to 7 and 8 to 15 as shown in the first row of Table 26-6-6. For Enhanced DMRS Type 2, the DMRS port numbers can be 1000 to 1011 and 1012 to 1023, instead of 0 to 11 and 12 to 23 as shown in the first row of Table 26-6-6.

[0657] Table 26-6-1 Additional parameters for [Enhanced DMRS Type 1 Support Method]

[0658]

[0659] Table 26-6-2 Additional parameters for [Enhanced DMRS Type 2 Support Method]

[0660]

[0661] Table 26-6-3 Available FD-OCC Indexes and Coefficients

[0662]

[0663] Table 26-6-4 Other available FD-OCC indices and coefficients

[0664]

[0665] Table 26-6-5 FD-OCC Indexes and Coefficients for [Enhanced DMRS Type 1 Support Method] and [Enhanced DMRS Type 2 Support Method]

[0666]

[0667] Table 26-6-6 Other FD-OCC indices and coefficients for [Enhanced DMRS Type 1 Support Method] and [Enhanced DMRS Type 2 Support Method]

[0668]

[0669] <Third Embodiment: Additional Support Methods for DMRS Types and Enhanced DMRS Types>

[0670] As an embodiment of this disclosure, an additional support method for DMRS type and enhanced DMRS type is described. This embodiment can be combined with other embodiments.

[0671] According to an embodiment, the antenna port field in the DCI format that can schedule PDSCH or PUSCH, which is one of the DCI formats other than DCI formats 0_0 and 1_0, can indicate to the UE one or more DMRS ports based on DMRS type and enhanced DMRS type.

[0672] For example, the base station can configure the DMRS port type for the UE through the antenna port field in DCI format 1_1 via dmrs-DownlinkForPDSCH-MappingTypeA and / or dmrs-DownlinkForPDSCH-MappingTypeB in the higher-layer signaling PDSCH-Config.

[0673] As another example, the base station can configure the DMRS port type for the UE via the antenna port field in DCI format 1_2 through dmrs-DownlinkForPDSCH-MappingTypeA-DCI-1-2 and / or dmrs-DownlinkForPDSCH-MappingTypeB-DCI-1-2 in the higher-layer signaling PDSCH-Config.

[0674] As another example, the base station can configure the DMRS port type indicated by the antenna port field in DCI format 1_3 for the UE via dmrs-DownlinkForPDSCH-MappingTypeA and / or dmrs-DownlinkForPDSCH-MappingTypeB in the higher-layer signaling PDSCH-Config. In other words, the UE can expect the DMRS type based on the same higher-layer signaling parameters to be indicated as the type of DMRS port indicated by the antenna port field in DCI formats 1_1 and 1_3.

[0675] As another example, the base station can configure the DMRS port type for the UE via the antenna port field in DCI format 4_2 through dmrs-DownlinkForPDSCH-MappingTypeA and / or dmrs-DownlinkForPDSCH-MappingTypeB in the higher-layer signaling pdsch-ConfigMulticast.

[0676] According to various embodiments of this disclosure, the UE and the base station can perform the following operations on all the above-described DCI formats.

[0677] According to an embodiment, when a PDSCH schedule is received from a base station via DCI, the UE can be notified via the Time Domain Resource Allocation (TDRA) field in the DCI that the PDSCH schedule is based on either PDSCH mapping type A or B.

[0678] Additionally, when the PDSCH mapping type indicated by the TDRA field in the DCI is PDSCH mapping type A, dmrs-DownlinkForPDSCH-MappingTypeA or dmrs-DownlinkForPDSCH-MappingTypeA-DCI-1-2 in PDSCH-config, or dmrs-DownlinkForPDSCH-MappingTypeA in pdsch-ConfigMulticast, can be configured for the UE as a higher-layer signaling for connecting to a DMRS type of mapping type A.

[0679] Additionally, when the PDSCH mapping type indicated by the TDRA field in the DCI is PDSCH mapping type B, dmrs-DownlinkForPDSCH-MappingTypeB or dmrs-DownlinkForPDSCH-MappingTypeB-DCI-1-2 in PDSCH-config, or dmrs-DownlinkForPDSCH-MappingTypeB in pdsch-ConfigMulticast, can be configured for the UE as a higher-layer signaling for connecting to a DMRS type of mapping type A.

[0680] Additionally, the UE can identify the DMRS type connected to the PDSCH mapping type indicated by the TDRA field in the DCI via higher-layer signaling, and can interpret the antenna port field in the DCI using the DMRS type. If the DMRS type connected to PDSCH mapping type A indicated by the TDRA field in the DCI is DMRS type 1, then the UE can interpret the antenna port field in the DCI using DMRS type 1.

[0681] Additionally, different code points in the TDRA field of the DCI can be used to indicate PDSCH mapping types A and B from the base station to the UE. To this end, different PDSCH mapping types can be configured for the UE via the higher-layer signaling mappingType, indicating different PDSCH-TimeDomainResourceAllocation values ​​for each entry in the higher-layer signaling pdsch-TimeDomainAllocationList.

[0682] Alternatively, the base station can configure higher-layer signaling for the UE to connect different DMRS types to different PDSCH mapping types. In this case, the UE can expect that the different DMRS types connected to different PDSCH mapping types are both normal DMRS types (e.g., introduced in NR Release 15) (e.g., DMRS type 1 for PDSCH mapping type A and DMRS type 2 for PDSCH mapping type B), or that the different DMRS types are both enhanced DMRS types (e.g., introduced in NR Release 18) (e.g., enhanced DMRS type 1 for PDSCH mapping type A and enhanced DMRS type 2 for PDSCH mapping type B). Conversely, the UE can not expect the different DMRS types connected to different PDSCH mapping types to correspond to normal DMRS types and enhanced DMRS types (e.g., the UE can not expect normal DMRS type 1 to be connected to PDSCH mapping type A and enhanced DMRS type 1 to be connected to PDSCH mapping type B).

[0683] Furthermore, the UE can expect to indicate different DMRS types for different DCI formats. For example, the UE can expect to configure enhanced DMRS type 1 connected to PDSCH mapping type A and enhanced DMRS type 2 connected to PDSCH mapping type B through the TDRA field in DCI format 1_1 from the base station, and configure DMRS type 1 connected to PDSCH mapping type A and DMRS type 2 connected to PDSCH mapping type B through the TDRA field in DCI format 1_2, and the UE can expect no restrictions on the configuration.

[0684] According to an embodiment, each of the above DCI formats can be monitored in the search space mentioned below.

[0685] The base station can configure the searchSpaceType in the higher-layer signaling searchSpace for the UE for a specific search space, so as to notify the UE whether the corresponding search space is a UE-specific search space or a group common search space.

[0686] If the common configuration for the UE is set to higher-layer signaling searchSpaceType, the corresponding search space can be the group common search space, and if the UE-specific configuration is set, the corresponding search space can be the UE-specific search space.

[0687] The common configuration can be set to searchSpaceType for the UE, and the common higher-layer parameters can include a higher-layer parameter called dci-Format4-2-r17. If the base station configures the UE with a higher-layer parameter called dci-Format4-2-r17 included in the common higher-layer parameters, the UE can monitor DCI format 4_2, including CRC scrambled with G-RNTI or G-CS-RNTI, in the corresponding group common search space.

[0688] UE-specific configurations can be set as searchSpaceTypes for the UE, and higher-layer parameters UE-specific can include higher-layer parameters called dci-Formats. The base station can configure higher-layer parameters called dci-Formats for the UE with a value of either "formats0-0-And-1-0" or "formats0-1-And-1-1". If the value of "formats0-0-And-1-0" is configured for the UE as a higher-layer parameter called dci-Formats, the UE can monitor DCI formats 0_0 and 1_0 in the corresponding UE-specific search space. If the value of "formats0-1-And-1-1" is configured for the UE as a higher-layer parameter called dci-Formats, the UE can monitor DCI formats 0_1 and 1_1 in the corresponding UE-specific search space.

[0689] The UE-specific configuration can be set for the UE as the searchSpaceType, and the higher-layer parameters specific to the UE can include a higher-layer parameter called dci-FormatsExt-r16. The base station can configure the UE with a higher-layer parameter called dci-FormatsExt-r16 having a value of either "formats0-2-And-1-2" or "formats0-1-And-1-1And-0-2-And-1-2". If the value of "formats0-2-And-1-2" is configured for the UE as a higher-layer parameter called dci-FormatsExt-r16, the UE can monitor DCI formats 0_2 and 1_2 in the corresponding UE-specific search space. If the value of "formats0-1-And-1-1And-0-2-And-1-2" is configured for the UE as a higher-layer parameter called dci-FormatsExt-r16, the UE can monitor DCI formats 0_1, 1_1, 0_2, and 1_2 in the corresponding UE-specific search space. If both dci-Formats and dci-FormatsExt-r16 are configured for the UE in the higher-level UE-specific parameters, the UE can ignore dci-Formats.

[0690] The UE-specific configuration can be set for the UE as the searchSpaceType, and the higher-layer parameters specific to the UE can include a higher-layer parameter called dci-FormatsMC. The base station can configure a higher-layer parameter called dci-FormatsMC for the UE with a value of "formats0-3", "formats1-3", or "formats0-3-And-1-3". If the value of "formats0-3" is configured for the UE as a higher-layer parameter called dci-FormatsMC, the UE can monitor DCI format 0_3 in the corresponding UE-specific search space. If the value of "formats1-3" is configured for the UE as a higher-layer parameter called dci-FormatsMC, the UE can monitor DCI format 1_3 in the corresponding UE-specific search space. If the value of "formats0-3-And-1-3" is configured for the UE as a higher-layer parameter called dci-FormatsMC, the UE can monitor DCI formats 0_3 and 1_3 in the corresponding UE-specific search space. If dci-FormatsMC is configured for the UE in the higher-level parameter UE-specific relative to the random UE-specific search space, the UE may not monitor DCI formats other than DCI formats 0_3 and / or 1_3 in the UE-specific search space.

[0691] If the base station configures the UE with a higher-layer parameter called dci-Format4-2-r17 that is included in the common higher-layer parameters, the UE can monitor DCI Format4_2, which includes CRC scrambled with G-RNTI or G-CS-RNTI, in the corresponding search space.

[0692] According to various embodiments of this disclosure, if only downlink scheduling DCI is considered, the UE can be configured to monitor at least one of DCI formats 1_0, 1_1, 1_2, 1_3 and 4_2 in a specific search space based on higher-layer signaling from the base station.

[0693] According to various embodiments of this disclosure, the UE can report to the base station which DMRS type it can support through UE capabilities.

[0694] Considering the DMRS used for PDSCH, the UE can report to the base station which DMRS type it supports, either normal DMRS type 1 or DMRS type 2 (e.g., as defined in NR Release 15). The UE can report to the base station whether only DMRS type 1 is supported, or whether both DMRS type 1 and DMRS type 2 are supported. The UE can always mandate support for DMRS type 1. Whether the UE supports DMRS type 2 can be optional. The corresponding UE capability report can be defined per feature set (FS) and can be a UE capability report for a specific frequency band combination. If no corresponding UE capability is reported to the base station, the UE can understand that only DMRS type 1 is supported. In the following text, the corresponding UE capability may be referred to as a DMRS type-related UE capability.

[0695] Considering the DMRS used for PDSCH, the UE can report to the base station which enhanced DMRS type is supported between enhanced DMRS type 1 and DMRS type 2 (e.g., as defined in NR Release 18). The UE can report to the base station whether only enhanced DMRS type 1 is supported, or report that both enhanced DMRS type 1 and enhanced DMRS type 2 are supported. The corresponding UE capability report can be optional for the UE. The corresponding UE capability can be defined per FS and can correspond to a UE capability report for a specific frequency band combination. If no corresponding UE capability is reported to the base station, the UE can understand that it does not support both enhanced DMRS type 1 and enhanced DMRS type 2. In the following text, the corresponding UE capability may be referred to as an enhanced DMRS type-related UE capability.

[0696] According to various embodiments of this disclosure, the following items are possible for the operation of the UE and the base station.

[0697] The UE can report to the base station that up to four different DMRS types (e.g., DMRS type 1, DMRS type 2, enhanced DMRS type 1, and enhanced DMRS type 2) are supported through UE capabilities associated with DMRS type and UE capabilities associated with enhanced DMRS type.

[0698] The UE may interpret the statement that four different DMRS types are supported as part of its capability report as meaning "the UE includes and reports all corresponding supported DMRS types." However, this may not necessarily be interpreted as meaning that the different reported DMRS types can be configured simultaneously via higher-layer signaling and indicated by the same or different DCI formats. In this case, even if the UE only considers and reports whether each DMRS type is supported to the base station, the base station may simultaneously transmit all configurations reported by the UE for different DMRS types to the UE, thus providing the UE with higher-layer signaling configurations that the UE cannot perform. In this situation, the UE may report more UE capabilities than it actually possesses.

[0699] As another approach, the UE can interpret the meaning of different DMRS types being supported as "the UE simultaneously includes and reports all corresponding supported DMRS types via higher-level signaling." In this case, the UE can actually support four different DMRS types, but since it is impossible to configure and be supported by DMRS types for the UE simultaneously, the UE can report fewer UE capabilities than it actually has by considering the number of DMRS types that can be configured simultaneously among the four types.

[0700] According to an embodiment, a base station that has received this UE capability can configure 4 for the UE via higher-layer signaling as the maximum number of different DMRS types that can be indicated by different DCI formats.

[0701] For example, the base station can configure a search space for the UE that can monitor DCI formats 1_1 and 1_2. Using the method described above, enhanced DMRS type 1 and enhanced DMRS type 2 can be configured for the UE as DMRS types that can be indicated by DCI format 1_1, and DMRS type 1 and DMRS type 2 can be configured as DMRS types that can be indicated by DCI format 1_2. In this case, the base station can configure a total of four different DMRS types for the UE across the monitorable DCI formats 1_1 and 1_2 in the search space, and therefore, the PDSCH DMRS port can be indicated to the UE.

[0702] As another example, the base station can configure a search space for the UE that can monitor DCI format 1_1, and another search space that can monitor DCI format 4_2. Using the above method, enhanced DMRS type 1 and enhanced DMRS type 2 can be configured for the UE as DMRS types that can be indicated by DCI format 1_1, and DMRS type 1 and DMRS type 2 can be configured as DMRS types that can be indicated by DCI format 4_2. In this case, the base station can configure two different corresponding DMRS types for the UE in each search space, and the base station can configure a total of four different DMRS types for the UE across two search spaces, and therefore, the PDSCH DMRS port can be indicated to the UE.

[0703] According to various embodiments of this disclosure, in order to perform channel estimation for PDSCH DMRS, the UE can preload channel estimation related parameters in its memory corresponding to a different number of DMRS types configured by the base station via higher-layer signaling for all DCI formats that can be monitored in all search spaces that the UE can monitor. Based on the loaded channel estimation related parameters, the UE can measure the channel based on a reference signal transmitted from the base station and periodically update the parameters based on the corresponding measurements. According to various embodiments, the aforementioned channel estimation related parameters are minimum mean square error (MMSE) filter coefficients and may be referred to as the channel correlation matrix.

[0704] [Channel Estimation Parameter Management Method 1] As described above, the channel estimation-related parameters can be loaded into the UE's memory before the UE decodes the DCI format that can be received at each monitoring location in the search space. This is because the latency may increase by the same amount when the UE loads the DMRS type that can be indicated by the DCI format after recognizing the DCI format.

[0705] [Channel Estimation Parameter Management Method 2] As another method, the UE can decode a specific DCI format in each search space, identify the DMRS type indicated by the DCI format, and then load the channel estimation-related parameters. The advantage of this method is that the UE does not prepare all channel estimation-related parameters for all configured DMRS types, and can load parameters only when decoding random DCI formats to save memory. However, the UE needs to perform the operation of preparing channel estimation-related parameters after DCI format decoding, and therefore additional delays may occur after DCI format decoding until channel estimation for PDSCH DMRS and demodulation operations for data in PDSCH.

[0706] In addition to the two methods mentioned above, the UE can manage DMRS-type channel estimation parameters configured for the UE by the base station via higher-layer signaling, and this can vary depending on the implementation of the UE.

[0707] As described above, the UE can manage channel estimation parameters of the DMRS type configured by the base station through higher-layer signaling, and the number of different DMRS types that the base station can configure for the UE through higher-layer signaling can be limited depending on the implementation of the UE. For example, if a particular UE implements a PDSCH DMRS channel estimation scheme, the maximum number of different DMRS types that the base station can configure for the UE through higher-layer signaling based on the above [channel estimation parameter management method 1] may be limited depending on the UE's memory state or the complexity of the channel estimation algorithm. As another example, if a particular UE implements a PDSCH DMRS channel estimation scheme based on the above [channel estimation parameter management method 2], the UE may need to load channel estimation-related parameters according to the DMRS type indicated by the DCI format whenever the UE decodes the DCI format, thus requiring additional processing time when the UE receives and decodes the PDSCH.

[0708] Furthermore, as mentioned above, UE capabilities related to DMRS type and enhanced DMRS type can report more or less UE capabilities than the actual capabilities of the UE. Therefore, the UE may not be able to reflect the implementation details of the UE's channel estimation parameters to report accurate UE capabilities to the base station. To address this issue, the UE and the base station can consider at least one combination of the following items.

[0709] Method 3-1

[0710] According to an embodiment, the UE can report to the base station the total number of different DMRS types that the UE can be configured with at most.

[0711] If the MMSE filter coefficient complexity and memory usage corresponding to DMRS type 1, DMRS type 2, enhanced DMRS type 1, and enhanced DMRS type 2 are similar or the same in the UE implementation, the UE can report one of values ​​2, 3, and 4 to the base station as a candidate value for the corresponding UE capability report. The UE must support DMRS type 1, therefore it may not need to report 1 as a candidate value to the base station. The UE can report 2 only if it has already reported at least two different supported DMRS types through DMRS type-related UE capabilities and enhanced DMRS type-related UE capabilities. The UE can report 3 only if it has already reported at least three different supported DMRS types through DMRS type-related UE capabilities and enhanced DMRS type-related UE capabilities. The UE can report 4 only if it has already reported at least four different supported DMRS types through DMRS type-related UE capabilities and enhanced DMRS type-related UE capabilities.

[0712] If, in the UE implementation, the MMSE filter coefficient complexity and memory usage corresponding to normal DMRS types (DMRS type 1 and DMRS type 2) are similar or the same, and the MMSE filter coefficient complexity and memory usage corresponding to enhanced DMRS types (enhanced DMRS type 1 and enhanced DMRS type 2) are similar or the same, and considering the different lengths of FD-OCC, the MMSE filter coefficient complexity and memory usage between normal and enhanced DMRS types are different from each other, then the UE can report the number of DMRS types and the number of enhanced DMRS types as candidate values ​​of UE capability to the base station. In this case, the UE can report 2 as the number of normal DMRS types, and if this value is not reported, the UE can assume that the UE only supports DMRS type 1. Only when the UE has already supported both DMRS type 1 and DMRS type 2 through the UE capability report related to the DMRS type can the UE report 2 as the number of normal DMRS types through the corresponding UE capability report. Additionally, the UE can report either 1 or 2 as the number of enhanced DMRS types. If this value is not reported, the UE can be assumed not to include enhanced DMRS types when considering the number of different DMRS types that can be configured simultaneously. The UE can only report 1 as the number of enhanced DMRS types through the corresponding UE capability report if it has already reported supporting only enhanced DMRS type 1 or both enhanced DMRS type 1 and enhanced DMRS type 2 through its enhanced DMRS type-related UE capability report. Similarly, the UE can only report 2 as the number of enhanced DMRS types through its enhanced DMRS type-related UE capability report if it has already reported supporting both enhanced DMRS type 1 and enhanced DMRS type 2 through its enhanced DMRS type-related UE capability report.

[0713] If, in the UE implementation, the MMSE filter coefficient complexity and memory usage corresponding to DMRS Type 1 and Enhanced DMRS Type 1 are similar or the same, and the MMSE filter coefficient complexity and memory usage corresponding to DMRS Type 2 and Enhanced DMRS Type 2 are similar or the same, and considering RE mapping, the number of CDM groups, etc., the MMSE filter coefficient complexity and memory usage between DMRS Type 1 and Enhanced DMRS Type 1, and between DMRS Type 2 and Enhanced DMRS Type 2 are different from each other, the UE can report 2 as the number of types that can be supported simultaneously in DMRS Type 1 and Enhanced DMRS Type 1 as a candidate value for UE capability, and report 1 or 2 as the number of types that can be supported simultaneously in DMRS Type 2 and Enhanced DMRS Type 2.

[0714] As described above, the aforementioned UE capabilities can be configured for all possible DMRS types configured for the UE. The higher-layer signaling configuration unit considered by the UE can be considered a specific bandwidth portion, a specific cell, all cells within a specific frequency band, all cells within a specific frequency band of a specific frequency band combination, or a specific UE.

[0715] For each specific bandwidth segment, each specific cell, all cells within a specific frequency band, all cells within a specific frequency band combination, or each specific UE, the aforementioned UE capabilities can be considered for all DMRS types available in a specific time unit. The specific time unit can be a time slot, frame, subframe, symbol, span as a unit of the UE's surveillance search space, or surveillance location within a specific time slot or span, or the aforementioned considerations can be made without any time unit constraints. When the aforementioned considerations are performed without any time unit constraints, the corresponding UE capabilities can be applied if the DMRS type is configured within the higher-layer signaling configuration unit considered by the UE.

[0716] After the UE reports the corresponding UE capabilities, the base station can combine these UE capabilities with the UE capabilities related to the DMRS type and the enhanced DMRS type reported by the UE, and transmit higher-level signaling configurations to the UE, limiting the number of different DMRS types configured for the UE within a specific time unit and higher-level signaling configuration unit. For example, if the UE has already reported that DMRS type 1 and DMRS type 2 are supported through the DMRS type-related UE capabilities, and the UE has already reported that enhanced DMRS type 1 is supported through the enhanced DMRS type-related UE capabilities, and when the MMSE filter coefficient complexity and memory usage corresponding to DMRS type 1, DMRS type 2, enhanced DMRS type 1, and enhanced DMRS type 2 are similar or the same in the UE implementation, and the UE has already reported 2 through the corresponding UE capabilities, then the UE can expect that two of the three different DMRS types (DMRS type 1, DMRS type 2, and enhanced DMRS type 1) reported through the DMRS type-related UE capabilities and the enhanced DMRS type-related UE capabilities will be configured by the base station for each of all cells in a specific frequency band for a specific frequency band combination. For example, DMRS Type 1 and Enhanced DMRS Type 1 can be configured for the UE by the base station for all cells within a specific frequency band combination across a specific frequency band, and based on this configuration, the PDSCH DMRS port according to DMRS Type 1 or Enhanced DMRS Type 1 can be indicated to the UE based on the antenna port field in a specific DCI format.

[0717] According to an embodiment, the aforementioned UE capabilities may include a maximum number of different DMRS types configured to be indicated to the UE through all downlink DCI formats (e.g., DCI formats 1_1, 1_2, 1_3, and 4_2) configured by the base station, enabling the UE to monitor DCI formats other than DCI format 1_0. When the UE reports the corresponding UE capabilities, it may be necessary to predetermine the cases where DMRS type-related UE capabilities (e.g., feature group 2-10) and enhanced DMRS type-related UE capabilities (e.g., feature group 40-4-1) have already been reported. The UE may report UE capabilities to the base station for each frequency band in each feature set or frequency band combination. The UE may report values ​​2, 3, or 4 to the base station through UE capabilities. As another example, the UE may report values ​​3 or 4 to the base station through UE capabilities.

[0718] [Method 3-2]

[0719] According to an embodiment, when a specific number or more DMRS types are configured for a UE via higher-layer signaling, the UE can have scheduling restrictions on the reception time points of PDSCHs that can be scheduled by the base station in the time domain, depending on the implementation of the UE. For example, if the base station configures a specific number or more different DMRS types for the UE via higher-layer signaling within a specific higher-layer signaling configuration unit (e.g., for each specific bandwidth portion, each specific cell, all cells within a specific frequency band, all cells within a specific frequency band combination, or each specific UE), then when the base station schedules PDSCHs, the UE can anticipate scheduling the PDSCHs after a specific time, symbol, or time slot from the reception time position of the DCI, which includes scheduling information about the PDSCHs. The specific number of DMRS types that cause the UE to have PDSCH scheduling restrictions can be notified to the UE by the base station via at least one combination of higher-layer signaling, MAC-CE signaling, and L1 signaling, can be transmitted by the UE to the base station via UE capabilities, or can be fixedly defined in the specification. Furthermore, the specific time interval, symbol length, or number of time slots required from the DCI reception time point, which can be considered as a scheduling constraint on PDSCH by the UE, can be notified to the UE by the base station through at least one combination of higher-layer signaling, MAC-CE signaling, and L1 signaling. This can be transmitted to the base station through the UE's capabilities or can be fixedly defined in the specification. For example, in the case where the UE reports 3 for the maximum simultaneously configurable DMRS types via [Method 3-1], if more than three DMRS types are configured for the UE, the UE can anticipate receiving PDSCH from the base station by considering the constraints on PDSCH scheduling.

[0720] Method 3-3

[0721] According to an embodiment, when a specific number or more DMRS types are configured for the UE via higher-layer signaling, the UE can impose scheduling restrictions on the reception time points of base station-schedulable PDSCHs, depending on the implementation of the UE. These scheduling restrictions can be defined by defining additional parameters within the PDSCH processing time. The PDSCH processing time can indicate the minimum time from when the UE receives the last symbol of the PDSCH to when a PUCCH containing HARQ-ACK information for the PDSCH is transmitted. For example, the UE can transmit a PUCCH containing HARQ-ACK information for the PDSCH after the PDSCH processing time from when the last symbol of the PDSCH is received.

[0722] When a UE receives scheduling information from a base station via DCI to receive PDSCH, the UE may require PDSCH processing time to apply the PDSCH transmission method indicated by the DCI (e.g., Modulation / Demodulation and Coding Indicator Index (MCS), demodulation reference signal related information, and time and frequency resource allocation information) and receive the PDSCH. The UE's PDSCH processing time can follow the following equation 5.

[0723] …Equation 5

[0724] Equation 5 above describes T proc,1 Each variable can have the following meanings.

[0725] - N1: Based on parameter set The number of symbols determined by UE processing capability 1 or 2 corresponding to the UE's capabilities.

[0726] According to an embodiment, if UE processing capability 1 is reported based on the UE's capability report, then N1 can have the values ​​in Table 27. If UE processing capability 2 is reported and UE processing capability 2 is configured to be available via higher-layer signaling, then N1 can have the values ​​in Table 28. Parameter Set It can correspond to The minimum value among them is used to maximize T. proc,1 . The parameter set of the PDCCH that schedules the PDSCH, the parameter set of the scheduled PDSCH, and the parameter set of the uplink channel through which to send HARQ-ACK can be indicated respectively.

[0727] - Regarding UE processing capability 2, if the UE has not yet reported a specific UE capability report to the base station (related to the simultaneous operation between UE processing capability 2 and enhanced DMRS type), the UE may not expect the base station to simultaneously configure processingType2Enabled as higher-layer signaling and configure the enhanced DMRS type, and d3 in Equation 5 can be regarded as 0.

[0728] According to the embodiment, if the UE has reported a specific UE capability report to the base station (related to simultaneous operation between UE processing capability 2 and enhanced DMRS type), and / or if enhanced DMRS type is configured for the UE via higher-layer signaling, the UE can consider d3 in Equation 5 as the value reported by the UE. If the subcarrier spacing is 15 kHz, the UE can report one of 0, 1, 2, 3, and 4 as the value of d3. If the subcarrier spacing is 30 kHz, the UE can report one of 0, 1, 2, 3, and 4. If the subcarrier spacing is 60 kHz in FR1, the UE can report one of 0, 1, 2, 3, 4, 5, 6, and 7. If the UE reports a specific UE capability report to the base station (related to simultaneous operation between UE processing capability 2 and enhanced DMRS type), and / or if higher-layer signaling for enhanced DMRS type is not configured for the UE, the UE can consider d3 in Equation 5 as 0.

[0729] Table 27 PDSCH processing time under PDSCH processing capacity 1

[0730]

[0731] Table 28 PDSCH processing time with PDSCH processing capacity 2

[0732]

[0733] - k:64

[0734] - T ext If the UE uses a shared spectrum channel access scheme, then the UE can calculate T. ext This is then applied to the PDSCH processing time. Otherwise, the UE assumes 0 as T. ext .

[0735] - If l1, which indicates the PDSCH DMRS location value, is 12, then N in Table 27 1,0 It has a value of 14; otherwise, it has a value of 13.

[0736] - For PDSCH mapping type A, if the last symbol of the PDSCH is the i-th symbol in the time slot where the PDSCH is sent andi Less than 7 ( ), d 1,1 It equals 7-i, otherwise, d 1,1 It equals 0.

[0737] - d2: If a PUCCH with a high-priority index and a PUCCH or PUSCH with a low-priority index overlap in time, then d2 for the PUCCH with the high-priority index can be configured as the value reported from the UE. Otherwise, d2 equals 0.

[0738] - In the case where PDSCH mapping type B is used for UE processing capability 1, d 1,1 The values ​​can be determined based on L (which is the number of symbols of the scheduled PDSCH) and d (which is the number of PDCCHs and the number of symbols on which the scheduled PDSCH overlaps), as described below.

[0739] - if d 1,1 =0.

[0740] - if and d 1,1 =7-L.

[0741] - if d 1,1 =min(d,1).

[0742] - if d 1,1 =3+d.

[0743] - In the case where PDSCH mapping type B is used for UE processing capability 2, d 1,1 The values ​​can be determined based on L (which is the number of symbols of the scheduled PDSCH) and d (which is the number of PDCCHs and the number of symbols on which the scheduled PDSCH overlaps), as described below.

[0744] - if d 1,1 =0.

[0745] - if and d 1,1 =7-L.

[0746] - if ,

[0747] - If a PDCCH for scheduling exists in a CORESET configured with 3 symbols, and the CORESET and the scheduling PDSCH have the same starting symbol, then d 1,1 Equals 3 (d) 1,1 =3).

[0748] - Otherwise, d 1,1 Equal to d (d 1,1 =d).

[0749] - When the UE supports capability 2 in a given serving cell, and the higher-layer signaling processingType2Enabled is configured to be enabled for the cell, the UE can apply the PDSCH processing time corresponding to UE processing capability 2.

[0750] If the position of the first uplink transmission symbol of the PUCCH containing HARQ-ACK information (which can be based on K1 defined as the HARQ-ACK transmission time point, the PUCCH resources used for HARQ-ACK transmission, and timing advance effects) is not earlier than T symbols after the last symbol of the PDSCH. proc,1 If the first uplink transmission symbol begins after the time interval, the UE is required to send a valid HARQ-ACK message. For example, the UE can only send a PUCCH including HARQ-ACK if the PDSCH processing time is sufficient. Otherwise, the UE cannot provide the base station with valid HARQ-ACK information corresponding to the scheduled PDSCH. proc,1 It can be used for normal or extended CP. When PDSCH is configured to have two PDSCH transmission opportunities within a single time slot, d 1,1 It can be calculated based on the timing of the first PDSCH transmission in the time slot.

[0751] According to an embodiment, when a specific number or more DMRS types are configured for a UE via higher-layer signaling, the UE may have a longer PDSCH processing time, taking into account d4 in Equation 5, depending on the implementation of the UE. For example, if the base station configures a specific number or more different DMRS types for the UE via higher-layer signaling within a specific higher-layer signaling configuration unit (e.g., for each specific bandwidth portion, each specific cell, all cells within a specific frequency band, all cells within a specific frequency band combination, or each specific UE), then when the base station schedules PDSCH, the UE can anticipate scheduling PDSCH after a specific time, symbol, or time slot from the reception time position of the DCI, which includes scheduling information about PDSCH. The specific number of DMRS types that cause the UE to have PDSCH scheduling limitations can be notified to the UE by the base station via at least one combination of higher-layer signaling, MAC-CE signaling, and L1 signaling, can be transmitted by the UE to the base station via UE capabilities, or can be fixedly defined in the specification.

[0752] Additionally, d4 in Equation 5, which can be considered by the UE as an additional delay in PDSCH processing time, can be a value reported by the UE through its UE capabilities, a value notified to the UE by the base station through at least one combination of higher-layer signaling, MAC-CE signaling, and L1 signaling, or a value fixedly determined in the specification.

[0753] If the UE reports d4 via its capabilities, its value can vary depending on the subcarrier spacing and the number of different DMRS types configured simultaneously. For example, if the subcarrier spacing is 15 kHz and the number of different DMRS types configured simultaneously is 3, the UE can report a value among 0, 1, 2, 3, and 4. If the subcarrier spacing is 15 kHz and the number of different DMRS types configured simultaneously is 4, the UE can report a value among 0, 1, 2, 3, 4, 5, 6, and 7. Similarly, considering subcarrier spacings of 30 kHz or 60 kHz, the UE can also report the d4 value via its capabilities.

[0754] Method 3-4

[0755] According to an embodiment, the UE can report to the base station, by considering other DCI formats besides DCI format 1_0 (e.g., DCI formats 1_1, 1_2, 1_3, and 4_2), whether dynamic handover between normal DMRS types (DMRS type 1 and DMRS type 2) and enhanced DMRS types (enhanced DMRS type 1 and enhanced DMRS type 2) can be performed using different DCI formats. The UE may need to support DMRS type 1 and be able to schedule PDSCHs scheduled by DCI format 1_0 based on DMRS type 1. Therefore, information such as system information that should also be received by UEs that have not yet accessed the cell is required; thus, DCI format 1_0 can be excluded when considering dynamic handover between DMRS types. If the UE has already reported the corresponding UE capabilities to the base station, the UE can expect that, as DMRS types can be indicated by all DCI formats capable of PDSCH scheduling (e.g., DCI formats 1_1, 1_2, 1_3, and 4_2) other than DCI format 1_0, the base station will configure at least one of DMRS type 1 and DMRS type 2, or at least one of enhanced DMRS type 1 and enhanced DMRS type 2, for the UE. The UE can also not expect to indicate normal DMRS types and enhanced DMRS types through different DCI formats. For example, the UE can expect to configure up to two different DMRS types through all DCI formats capable of PDSCH scheduling other than DCI format 1_0, and these two different DMRS types can be all normal DMRS types or enhanced DMRS types.

[0756] If the UE has not yet reported the corresponding UE capabilities to the base station, the UE can assume that the above-mentioned restrictions do not exist, and can expect that, as DMRS types that can be indicated by all DCI formats capable of PDSCH scheduling (e.g., DCI formats 1_1, 1_2, 1_3, and 4_2) other than DCI format 1_0, the base station will configure at least one of DMRS type 1, DMRS type 2, enhanced DMRS type 1, and enhanced DMRS type 2 for the UE. For example, the UE can expect to configure up to four different DMRS types using all DCI formats capable of PDSCH scheduling other than DCI format 1_0.

[0757] According to various embodiments of this disclosure, the base station may notify the UE of at least one combination of [method 3-1] to [method 3-4] above via at least one combination of higher-layer signaling, MAC-CE signaling or L1 signaling, or it may be anticipated that at least one combination of [method 3-1] to [method 3-4] will be fixedly defined in the specification.

[0758] Furthermore, if the base station notifies the UE of one or more specific combinations of methods via at least one combination of higher-layer signaling, MAC-CE signaling, or L1 signaling, it may mean that the UE does not support one or more other specific combinations of methods. For example, the UE may anticipate that the method and procedure for reporting channel state information initiated by the UE as described above is fixedly defined in the specification [Method 3-1]. As another example, the base station may notify the UE via at least one combination of higher-layer signaling, MAC-CE signaling, or L1 signaling [Method 3-4], and in this case, the UE may consider that the base station has notified that it does not support [Method 3-1].

[0759] According to an embodiment, the UE can report to the base station whether it can support at least one combination of [Method 3-1] to [Method 3-4] as a UE capability. In this case, if the UE has already reported to the base station whether it can support one or more specific combinations of methods as a UE capability, it can be assumed that the UE has reported that it cannot support one or more other specific combinations of methods. For example, the UE can report to the base station whether it can support [Method 3-1] or [Method 3-2]. As another example, the UE can report to the base station that it can support [Method 3-1], and such a UE capability report can imply that the UE cannot support [Method 3-2].

[0760] Figure 21 The operation of a UE transmitting or receiving demodulated signals in a wireless communication system according to embodiments of the present disclosure is illustrated.

[0761] In operation 2100, the UE may send UE capabilities to the base station. Reportable UE capability signaling may involve at least one combination of DMRS type-related UE capabilities, enhanced DMRS type-related UE capabilities, search space-related UE capabilities, UE capabilities supporting DCI formats (e.g., DCI formats 1_2, 1_3, or 4_2), and indications of whether UE capabilities [Method 3-1] to [Method 3-4] are supported. Omitting operation 2100 is also possible.

[0762] In operation 2105, the UE can receive higher-layer signaling from the base station based on the reported UE capabilities. The UE can define higher-layer parameters related to one or more combinations of higher-layer signaling associated with the search space, higher-layer signaling associated with the DCI format that can be monitored in each search space, higher-layer signaling associated with the DMRS type and enhanced DMRS type, and higher-layer signaling received from the base station for [Method 3-1] to [Method 3-4], and can use one of the higher-layer parameters. The total number of DMRS types that can be indicated by different DCI formats can be configured for the UE based on the UE capabilities reported in operation 2100.

[0763] In operation 2110, the UE can receive PDCCH from the base station. PDCCH may include information on scheduling PDSCH and indicate the DMRS port based on a specific DMRS type.

[0764] In operation 2115, the UE can receive the PDSCH and perform DMRS channel estimation. If the UE operates based on [Method 3-2] or [Method 3-3], the UE can anticipate ensuring a specific time length from the last symbol of the PDCCH to the scheduled PDSCH when scheduling the PDSCH. Thereafter, the UE can send a PUCCH including HARQ-ACK information corresponding to the PDSCH to the base station after the PDSCH processing time from the last symbol received from the PDSCH.

[0765] The flowcharts above illustrate exemplary methods that can be implemented according to the principles of this disclosure, and various modifications can be made to the methods shown in the flowcharts of this specification. For example, a series of operations are illustrated, but the various operations in the figures may also overlap, occur in parallel, occur in different orders, or occur multiple times. In another example, an operation may be omitted or replaced with another operation.

[0766] Figure 22 Operation of a base station for transmitting or receiving demodulated signals in a wireless communication system, according to embodiments of the present disclosure, is illustrated.

[0767] In operation 2200, the base station can receive UE capabilities from the UE. Reportable UE capability signaling may involve at least one combination of DMRS type-related UE capabilities, enhanced DMRS type-related UE capabilities, search space-related UE capabilities, UE capabilities supporting DCI formats (e.g., DCI formats 1_2, 1_3, or 4_2), and indications of whether UE capabilities [method 3-1] to [method 3-4] are supported. Omitting operation 2200 is also possible.

[0768] In operation 2205, the base station can send higher-layer signaling to the UE based on the received UE capabilities. The base station can define higher-layer signaling associated with the search space, higher-layer signaling associated with the DCI formats that can be monitored in each search space, higher-layer signaling associated with DMRS types and enhanced DMRS types, and higher-layer parameters associated with one or more combinations of higher-layer signaling for [Method 3-1] to [Method 3-4], and can send one of the higher-layer parameters to the UE. In operation 2200, the base station can configure the total number of DMRS types that can be indicated by different DCI formats based on the UE capabilities received from the UE.

[0769] In operation 2210, the base station may send a PDCCH to the UE. The PDCCH may include information on scheduling the PDSCH and indicate the DMRS port based on a specific DMRS type.

[0770] In operation 2215, the base station may send a PDSCH to the UE, and the UE is expected to perform DMRS channel estimation. If the base station operates based on [Method 3-2] or [Method 3-3], the base station may perform PDSCH scheduling such that a specific time length is guaranteed from the last symbol of the PDCCH until the scheduled PDSCH. Thereafter, the base station may expect the UE to send a PUCCH including HARQ-ACK information corresponding to the PDSCH after the PDSCH processing time from the last symbol received from the PDSCH.

[0771] The flowchart above illustrates a method that can be implemented according to the principles of this disclosure, and various modifications can be made to the method shown in the flowchart herein. For example, a series of operations are illustrated, but the various operations in the figures may also overlap, occur in parallel, occur in different orders, or occur multiple times. In another example, an operation may be omitted or replaced with another operation.

[0772] Figure 23 The structure of a UE in a wireless communication system according to an embodiment of the present disclosure is shown.

[0773] refer to Figure 23 The UE may include transceivers, which collectively refer to UE receiver 2300 and UE transmitter 2310, memory (not shown), and UE processor 2305 (or UE controller or processor). UE transceivers 2300 and 2310, memory, and UE processor 2305 can operate according to the communication methods of the UE described above. The components of the UE are not limited to the examples described above. For example, the UE may include more or fewer components than those described above. Furthermore, the transceiver, memory, and processor may be implemented as a single chip.

[0774] A transceiver can transmit / receive signals with a base station. These signals may include control information and data. For this purpose, a transceiver may include an RF transmitter configured to up-convert and amplify the frequency of the transmitted signal, an RF receiver configured to amplify the received signal with low noise and down-convert its frequency, and so on. However, this is only one embodiment of a transceiver, and the components of a transceiver are not limited to RF transmitters and RF receivers.

[0775] In addition, the transceiver can receive signals via a radio channel, output them to the processor, and transmit signals output from the processor via a radio channel.

[0776] The memory can store programs and data required for the operation of the UE. Additionally, the memory can store control information or data included in signals sent / received by the UE. The memory can include storage media such as ROM, RAM, hard disk, CD-ROM, or DVD, or a combination of storage media. Furthermore, the memory can include multiple memories.

[0777] Furthermore, the processor can control a series of processes that enable the UE to operate according to the embodiments described above. For example, the processor can control components of the UE to receive DCIs configured in two layers to receive multiple PDSCHs simultaneously. The processor may include multiple processors, and the processors can perform operations to control the components of the UE by executing programs stored in memory.

[0778] Figure 24 The structure of a base station in a wireless communication system according to an embodiment of the present disclosure is shown.

[0779] refer to Figure 24 The base station may include transceivers, which generally refer to base station receiver 2400 and base station transmitter 2410, memory (not shown), and base station processor 2405 (or base station controller or processor). The base station transceivers 2400 and 2410, memory, and base station processor 2405 can operate according to the communication method of the UE described above. However, the components of the base station are not limited to the examples described above. For example, the base station may include more or fewer components than those described above. Furthermore, the transceiver, memory, and processor may be implemented as a single chip.

[0780] A transceiver can transmit / receive signals with a UE. These signals may include control information and data. For this purpose, a transceiver may include an RF transmitter configured to up-convert and amplify the frequency of the transmitted signal, an RF receiver configured to perform low-noise amplification and down-convert the frequency of the received signal, and so on. However, this is only one embodiment of a transceiver, and the components of the transceiver are not limited to RF transmitters and RF receivers.

[0781] In addition, the transceiver can receive signals via a radio channel, output them to the processor, and transmit signals output from the processor via a radio channel.

[0782] The memory can store programs and data required for the operation of the base station. Additionally, the memory can store control information or data included in signals transmitted / received by the base station. The memory can include storage media such as ROM, RAM, hard disk, CD-ROM, or DVD, or a combination of storage media. Furthermore, the memory can include multiple memories.

[0783] The processor can control a series of processes that enable the base station to operate according to the embodiments of the present disclosure described above. For example, the processor can control components of the base station to configure and transmit a DCI configured in two layers, including allocation information regarding multiple PDSCHs. The processor may include multiple processors, and the processor can perform operations controlling the components of the base station by executing programs stored in memory.

[0784] The methods disclosed in the claims and / or the methods of the embodiments described in this disclosure may be implemented by hardware, software, or a combination of hardware and software.

[0785] When the method is implemented in software, a computer-readable storage medium may be provided for storing one or more programs (software modules). One or more programs stored in the computer-readable storage medium may be configured to be executed by one or more processors within an electronic device. At least one program includes instructions to cause the electronic device to perform the method according to various embodiments of the present disclosure as defined by the appended claims and / or disclosed herein.

[0786] These programs (software modules or software) can be stored in non-volatile memory, including random access memory and flash memory, read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), disk storage devices, optical disc ROM (CD-ROM), digital versatile optical disc (DVD), or other types of optical storage devices or magnetic tape cartridges. Alternatively, any combination of some or all of them can form a memory storing programs. Furthermore, multiple such memories can be included in an electronic device.

[0787] Furthermore, the program can be stored in an attachable storage device that can be accessed by the electronic device via a communication network such as the Internet, intranet, local area network (LAN), wide area network (WLAN), and storage area network (SAN), or a combination thereof. Such a storage device can access the electronic device via an external port. Additionally, a separate storage device on the communication network can access portable electronic devices.

[0788] In the detailed embodiments described above, elements included in this disclosure are represented in a singular or plural form according to the presented embodiments. However, for ease of description, the singular or plural form is suitably chosen for the presented situation, and this disclosure is not limited to elements represented in a singular or plural form. Thus, an element represented in a plural form may also include a single element, or an element represented in a singular form may include multiple elements.

[0789] The embodiments of this disclosure described and illustrated in the specification and drawings are merely specific examples presented to facilitate the explanation of the technical content of this disclosure and to aid in understanding it, and are not intended to limit the scope of this disclosure. That is, it will be apparent to those skilled in the art that other variations based on the technical concepts of this disclosure can be implemented. Furthermore, the various embodiments described above can be combined as needed. For example, a portion of one embodiment of this disclosure can be combined with a portion of another embodiment to operate a base station and a terminal.

[0790] For example, a portion of the first embodiment of this disclosure can be combined with a portion of the second embodiment of this disclosure to operate a base station and a terminal. Furthermore, although the above embodiments have been described based on an FDD LTE system, other variations based on the technical ideas of the embodiments can also be implemented in other communication systems such as TDD LTE and 5G or NR systems.

[0791] In the accompanying drawings describing the methods of this disclosure, the order described does not always correspond to the order in which the steps of each method are performed, and the order between the steps may be changed or the steps may be performed in parallel.

[0792] Alternatively, in the accompanying drawings describing the methods of this disclosure, some elements may be omitted without departing from the basic spirit and scope of this disclosure, and only some elements may be included.

[0793] Furthermore, in the methods of this disclosure, some or all of the contents of each embodiment may be combined without departing from the basic spirit and scope of this disclosure.

[0794] While this disclosure has been shown and described with reference to various embodiments thereof, those skilled in the art will understand that various changes in form and detail may be made therein without departing from the spirit and scope of this disclosure as defined by the appended claims and their equivalents.

Claims

1. A user equipment (UE) in a wireless communication system, the UE comprising: transceiver; Memory, which stores one or more computer programs; and One or more processors, communicatively coupled to transceivers and memory, One or more of the programs include computer-executable instructions that, when executed individually or jointly by the one or more processors, cause the UE to: Send to the base station first UE capability information indicating the supported demodulation reference signal (DMRS) type for downlink and second UE capability information indicating the supported enhanced DMRS type for physical downlink shared channel (PDSCH). The third UE capability information is sent to the base station, the third UE capability information including a value indicating the maximum number of DMRS types for PDSCH across all downlink control information (DCI) formats, and Receive DMRS for PDSCH from the base station based on at least one of the supported DMRS types and supported enhanced DMRS types. The number of at least one DMRS type is equal to or less than the maximum number of DMRS types.

2. The UE according to claim 1, in, Supported DMRS types include at least one of DMRS type 1 and DMRS type 2, and Among them, the supported enhanced DMRS types include at least one of enhanced DMRS type 1 and enhanced DMRS type 2.

3. The UE according to claim 1, in, The maximum number of DMRS types is configured for each cell, and The value is one of 2, 3, and 4.

4. The UE according to claim 1, wherein, The third UE capability information is sent for each feature set.

5. A base station in a wireless communication system, the base station comprising: transceiver; Memory, which stores one or more computer programs; and One or more processors, communicatively coupled to transceivers and memory, One or more programs include computer-executable instructions that, when executed individually or jointly by the one or more processors, cause the base station to: Receive first UE capability information indicating the supported demodulation reference signal (DMRS) types for downlink and second UE capability information indicating the supported enhanced DMRS types for physical downlink shared channel (PDSCH) from the user equipment (UE). Receive third UE capability information from the UE, the third UE capability information including a value indicating the maximum number of DMRS types for PDSCH across all downlink control information (DCI) formats, and Based on at least one of the supported DMRS types and supported enhanced DMRS types, send DMRS for PDSCH to the UE. The number of at least one DMRS type is equal to or less than the maximum number of DMRS types.

6. The base station according to claim 5, in, Supported DMRS types include at least one of DMRS type 1 and DMRS type 2, and Among them, the supported enhanced DMRS types include at least one of enhanced DMRS type 1 and enhanced DMRS type 2.

7. The base station according to claim 5, in, The maximum number of DMRS types is configured for each cell, and The value is one of 2, 3, and 4.

8. The base station according to claim 5, wherein, The third UE capability information is received for each feature set.

9. A method performed by a user equipment (UE) in a wireless communication system, the method comprising: Send to the base station first UE capability information indicating the supported demodulation reference signal (DMRS) type for downlink and second UE capability information indicating the supported enhanced DMRS type for physical downlink shared channel (PDSCH); Send third UE capability information to the base station, the third UE capability information including a value indicating the maximum number of DMRS types for PDSCH across all downlink control information (DCI) formats; as well as Receive DMRS for PDSCH from the base station based on at least one of the supported DMRS types and supported enhanced DMRS types. The number of at least one DMRS type is equal to or less than the maximum number of DMRS types.

10. The method according to claim 9, in, Supported DMRS types include at least one of DMRS type 1 and DMRS type 2, and Among them, the supported enhanced DMRS types include at least one of enhanced DMRS type 1 and enhanced DMRS type 2.

11. The method according to claim 9, in, The maximum number of DMRS types is configured for each cell, and The value is one of 2, 3, and 4.

12. The method according to claim 9, wherein, The third UE capability information is sent for each feature set.

13. A method performed by a base station in a wireless communication system, the method comprising: Receive first UE capability information indicating the supported demodulation reference signal (DMRS) type for downlink and second UE capability information indicating the supported enhanced DMRS type for physical downlink shared channel (PDSCH); Receive third UE capability information from the UE, the third UE capability information including a value indicating the maximum number of DMRS types for PDSCH across all downlink control information DCI formats; as well as Based on at least one of the supported DMRS types and supported enhanced DMRS types, send DMRS for PDSCH to the UE. The number of at least one DMRS type is equal to or less than the maximum number of DMRS types.

14. The method according to claim 13, in, Supported DMRS types include at least one of DMRS type 1 and DMRS type 2, and Among them, the supported enhanced DMRS types include at least one of enhanced DMRS type 1 and enhanced DMRS type 2.

15. The method according to claim 13, in, The maximum number of DMRS types is configured for each cell, and The value is one of 2, 3, and 4.

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