Method and apparatus for dynamic switching among transmission and reception types of data and reference signals in wireless communication system

Abstract

The present disclosure provides a method performed by a terminal in a wireless communication system. The method comprises: receiving first information indicating at least one DMRS type from a base station via RRC signaling; receiving, from the base station via MAC-CE signaling, second information indicating whether to activate an enhanced DMRS type corresponding to the at least one DMRS type; and receiving a PDSCH from the base station or transmitting a PUSCH to the base station on the basis of the enhanced DMRS type in a case where the second information indicates activation of the enhanced DMRS type.

Description

Technical Field

[0001] The present disclosure relates to operations of a terminal and a base station in a wireless communication system. Specifically, the present disclosure relates to a method for dynamically changing a scheme for transmitting or receiving data and a reference signal in a wireless communication system, and a device capable of executing the method. Background Art

[0002] The fifth generation (5G) mobile communication technology defines a wide frequency band, making high transmission rates and new services possible, and can be implemented not only in "below 6 GHz" frequency bands such as 3.5 GHz, but also in "above 6 GHz" frequency bands called millimeter waves including 28 GHz and 39 GHz. In addition, the implementation of the sixth generation (6G) mobile communication technology (called Beyond 5G System) in the terahertz frequency band (e.g., 95 GHz to 3 THz frequency band) has been considered in order to achieve a transmission rate 50 times faster than that of 5G mobile communication technology and an ultra-low latency of one tenth of 5G.

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

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

[0005] In addition, in terms of air interface architecture / protocol, standardization is being conducted on various technologies such as the Industrial Internet of Things (IIoT) for supporting new services through interworking and integration with other industries, Integrated Access and Backhaul (IAB) for providing nodes for network service area expansion by supporting wireless backhaul links and access links in an integrated manner, mobility enhancement including conditional handover and dual active protocol stack (DAPS) handover, and two-step random access (NR's 2-step RACH) for simplifying the random access procedure. In terms of system architecture / services, standardization is also being conducted on various technologies such as the 5G baseline architecture (e.g., service-based architecture or service-based interface) for combining network function virtualization (NFV) and software defined network (SDN) technologies, and mobile edge computing (MEC) for receiving services based on UE location.

[0006] As 5G mobile communication systems are commercialized, the already exponentially growing number of connected devices will be connected to the communication network, and it is therefore expected that enhanced functionality and performance of the 5G mobile communication system and integrated operations of the connected devices will be necessary. To this end, new research related to the following technologies is scheduled: extended reality (XR) for effectively supporting augmented reality (AR), virtual reality (VR), mixed reality (MR), etc., 5G performance improvement and complexity reduction by utilizing artificial intelligence (AI) and machine learning (ML), AI service support, metaverse service support, and drone communication.

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

[0008] The above information is presented as background information only to assist in understanding the present disclosure. No determination has been made, and no assertion has been made, as to whether any of the above content may be applicable as prior art to the present disclosure. Summary of the invention

[0009] Technical issues

[0010] The present disclosure will provide an apparatus and method for efficiently providing a service in a wireless communication system.

[0011] Specifically, the present disclosure provides a method and apparatus for applying an enhanced demodulation reference signal (DMRS) type in a wireless communication system.

[0012] In addition, the present disclosure provides a method for switching between an existing DMRS type and an enhanced DMRS type in a wireless communication system.

[0013] Technical Solution

[0014] According to one aspect of the present disclosure, a method performed by a terminal in a wireless communication system includes: receiving first information indicating at least one demodulation reference signal (DMRS) type from a base station via radio resource control (RRC) signaling, receiving second information indicating whether to activate an enhanced DMRS type corresponding to the at least one DMRS type from the base station via medium access control-control element (MAC-CE) signaling, and when the second information indicates activation of the enhanced DMRS type, receiving a physical downlink shared channel (PDSCH) from the base station or sending a physical uplink shared channel (PUSCH) to the base station based on the enhanced DMRS type.

[0015] According to another aspect of the present disclosure, a method performed by a base station in a wireless communication system includes: sending first information indicating at least one DMRS type to a terminal via RRC signaling; sending second information indicating whether to activate an enhanced DMRS type corresponding to at least one DMRS type to the terminal via MAC-CE signaling; and when the second information indicates activation of the enhanced DMRS type, sending PDSCH to the terminal or receiving PUSCH from the terminal based on the enhanced DMRS type.

[0016] According to another aspect of the present disclosure, a terminal in a wireless communication system includes a transceiver and a processor, which is coupled to the transceiver and configured to receive first information indicating at least one DMRS type from a base station via RRC signaling, receive second information indicating whether to activate an enhanced DMRS type corresponding to the at least one DMRS type from the base station via MAC-CE signaling, and receive PDSCH from the base station or send PUSCH to the base station based on the enhanced DMRS type when the second information indicates activation of the enhanced DMRS type.

[0017] According to another aspect of the present disclosure, a base station in a wireless communication system includes a transceiver and a processor, which is coupled to the transceiver and configured to send first information indicating at least one DMRS type to a terminal via RRC signaling, send second information indicating whether to activate an enhanced DMRS type corresponding to the at least one DMRS type to the terminal via MAC-CE signaling, and when the second information indicates activation of the enhanced DMRS type, send PDSCH to the terminal or receive PUSCH from the terminal based on the enhanced DMRS type.

[0018] The technical problems to be achieved in the embodiments of the present disclosure are not limited to the above-mentioned technical problems, and those skilled in the art to which the present disclosure belongs will clearly understand other technical problems not mentioned herein from the following description.

[0019] Before proceeding to the following detailed description, it may be helpful to set forth definitions of certain words and phrases used throughout this patent document: the terms "include" and "comprising," and their derivatives, mean inclusion without limitation; the term "or" is inclusive, meaning and / or; the phrases "associated with" and "associated with," and their derivatives may mean including, included within, interconnected with, containing, contained within, connected to or connected with, coupled to or coupled with, communicable with, cooperating with, interleaved, juxtaposed, proximate to, incorporated into or incorporated with, having, having the characteristics of, and the like; and the term "controller" refers to any device, system, or portion thereof that controls at least one operation, such device being implemented in hardware, firmware, or software, or some combination of at least two thereof. It should be noted that the functionality associated with any particular controller may be centralized or distributed, whether locally or remotely.

[0020] In addition, the various functions described below can be implemented or supported by one or more computer programs, each of which is formed by a computer-readable program code and embodied in a computer-readable medium. The terms "application" and "program" refer to one or more computer programs, software components, instruction sets, processes, functions, objects, classes, instances, related data or a part thereof suitable for implementation with a suitable computer-readable program code. The phrase "computer-readable program code" includes any type of computer code, including source code, object code and executable code. The phrase "computer-readable medium" includes any type of medium that can be accessed by a computer, such as a read-only memory (ROM), a random access memory (RAM), a hard drive, a compact disk (CD), a digital video disc (DVD) or any other type of memory. "Non-transitory" computer-readable media does not include wired, wireless, optical or other communication links that transmit temporary electrical signals or other signals. Non-transitory computer-readable media include media that can permanently store data and media that can store data and overwrite it later, such as rewritable optical disks or erasable memory devices.

[0021] Definitions for certain words and phrases are provided in this patent document, those of ordinary skill in the art should understand that in many, if not most instances, such definitions apply to prior, as well as future uses of such defined words and phrases.

[0022] Beneficial Effects

[0023] According to an embodiment of the present disclosure, an apparatus and method for efficiently providing a service in a wireless communication system are provided.

[0024] In addition, according to an embodiment of the present disclosure, data may be transmitted and received by applying an enhanced DMRS type.

[0025] Furthermore, according to an embodiment of the present disclosure, switching between an existing DMRS type and an enhanced DMRS type may be performed.

[0026] Effects that can be obtained in the present disclosure are not limited to the above-mentioned effects, and other unmentioned effects will be clearly understood by a person of ordinary skill in the art to which the present disclosure pertains. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above and other aspects, features and advantages of certain embodiments of the present disclosure will become more apparent from the following description in conjunction with the accompanying drawings, in which:

[0028] 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;

[0029] Figure 2The frame, subframe and time slot structure in a wireless communication system according to an embodiment of the present disclosure is shown;

[0030] Figure 3 An example of the configuration of a bandwidth part in a wireless communication system according to an embodiment of the present disclosure is shown;

[0031] Figure 4 An example of configuration of a control region of a downlink control channel in a wireless communication system according to an embodiment of the present disclosure is shown;

[0032] Figure 5A The structure of a downlink control channel in a wireless communication system according to an embodiment of the present disclosure is shown;

[0033] Figure 5B It shows that a user equipment (UE) in a wireless communication system according to an embodiment of the present disclosure can have multiple physical downlink control channel (PDCCH) monitoring positions within a time slot through a span;

[0034] Figure 6 An example of a discontinuous reception (DRX) operation in a wireless communication system according to an embodiment of the present disclosure is shown;

[0035] Figure 7 An example of base station (BS) beam allocation configured according to a transmission configuration indication (TCI) state in a wireless communication system according to an embodiment of the present disclosure is shown;

[0036] Figure 8 An example of a method for allocating TCI states for a PDCCH in a wireless communication system according to an embodiment of the present disclosure is shown;

[0037] Fig. 9 A TCI indication medium access control (MAC) control element (CE) signaling structure for a PDCCH demodulation reference signal (DMRS) in a wireless communication system according to an embodiment of the present disclosure is shown;

[0038] Fig.10 An example of a beam configuration of a control resource set (CORESET) and a search space in a wireless communication system according to an embodiment of the present disclosure is shown;

[0039] Fig.11 A diagram showing a method for a base station and a terminal in a wireless communication system to transmit or receive data in consideration of a downlink data channel and a rate matching resource according to an embodiment of the present disclosure;

[0040] Fig.12A diagram showing a method of selecting a receivable control resource set in consideration of a priority when a terminal receives a downlink control channel in a wireless communication system according to an embodiment of the present disclosure;

[0041] Fig.13 An example of frequency axis resource allocation of a physical downlink shared channel (PDSCH) in a wireless communication system according to an embodiment of the present disclosure is shown;

[0042] Fig.14 An example of allocation of time axis resources of a PDSCH in a wireless communication system according to an embodiment of the present disclosure is shown;

[0043] Fig.15 An example of allocation of time axis resources according to subcarrier spacings of a data channel and a control channel in a wireless communication system according to an embodiment of the present disclosure is shown;

[0044] Fig.16 The beam configuration and activation process of the PDSCH according to an embodiment of the present disclosure is shown;

[0045] Fig.17 The wireless protocol structures of a BS and a UE in a single cell environment, a carrier aggregation (CA) environment, and a dual connectivity (DC) environment in a wireless communication system according to an embodiment of the present disclosure are shown;

[0046] Fig.18 An example of configuration of antenna ports and resource allocation for cooperative communication in a wireless communication system according to an embodiment of the present disclosure is shown;

[0047] Fig.19 An example of configuration of downlink control information (DCI) for cooperative communication in a wireless communication system according to an embodiment of the present disclosure is shown;

[0048] Fig. 20 A diagram showing an enhanced PDSCH TCI state activation / deactivation MAC-CE structure according to an embodiment of the present disclosure;

[0049] Fig.21 A diagram illustrating the operation of a base station according to an embodiment of the present disclosure;

[0050] Fig. 22 A diagram showing the operation of a terminal according to an embodiment of the present disclosure;

[0051] Fig.23 The structure of a UE in a wireless communication system according to an embodiment of the present disclosure is shown; and

[0052] Fig.24 A structure of a BS in a wireless communication system according to an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0053] Discussed below Figures 1 to 24 The various embodiments used to describe the principles of the present disclosure in this patent document are exemplary only and should not be interpreted in any way as limiting the scope of the present disclosure. Those skilled in the art will understand that the principles of the present disclosure can be implemented in any appropriately arranged system or device.

[0054] Embodiments of the present disclosure are described with reference to the accompanying drawings.

[0055] When describing the embodiments, descriptions related to well-known technical contents in the field to which the present disclosure belongs will be omitted, and these technical contents are not directly related to the present disclosure. Omission of unnecessary descriptions is to prevent the main concept of the present disclosure from being obscured and to convey the main concept more clearly.

[0056] In the accompanying drawings, some elements may be exaggerated, omitted or schematically shown. In addition, the size of each element does not fully reflect the actual size. In the accompanying drawings, the same or corresponding elements have the same reference numerals.

[0057] By referring to the embodiments described in detail below in conjunction with the accompanying drawings, the advantages and features of the present disclosure and the ways to achieve them will become apparent. However, the present 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 and inform those skilled in the art of the scope of the present disclosure, as well as the appended claims. Throughout the specification, the same or similar reference numerals represent the same or similar elements. In addition, when describing the present disclosure, when it is determined that the description may make the subject matter of the present disclosure unnecessarily unclear, the detailed description of the known functions or configurations incorporated herein will be omitted. The terms to be described below are terms defined in view of the functions in the present disclosure, and may be different according to the user, the user's intention or custom. Therefore, the definition of the term should be made based on the content throughout the entire specification.

[0058] In the following description, the BS is an entity that allocates resources to the terminal, and may be at least one of a gNode B, an eNode B, a Node B, a BS, a wireless access unit, a BS controller, and a node on a network. The terminal may include a UE, a mobile station (MS), a cellular phone, a smart phone, a computer, or a multimedia system capable of performing a communication function. In the present disclosure, "downlink" refers to a radio link via which the BS sends a signal to the terminal, and "uplink" refers to a radio link via which the terminal sends a signal to the BS. In addition, although the following description may be directed to a Long Term Evolution (LTE) or LTE-A system by way of example, embodiments of the present disclosure may also be applied to other communication systems having a technical background or channel type similar to the embodiments of the present disclosure. Examples of other communication systems may include 5G New Radio (NR) developed beyond LTE-A, and in the following description,

[0059] "5G" may be a concept covering existing LTE, LTE-A or other similar services. In addition, based on the determination of those skilled in the art, the present disclosure may be applied to other communication systems through some modifications without obviously departing from the scope of the present disclosure.

[0060] Here, it will be understood that each box of the flowchart diagram and the combination of boxes in the flowchart diagram can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device create a device for realizing the function specified in one or more boxes of the flowchart. These computer program instructions can also be stored in a computer-available or computer-readable memory, which can instruct the computer or other programmable data processing device to operate in a particular manner, so that the instructions stored in the computer-available or computer-readable memory produce a manufactured product including instructions, which means to realize the function specified in one or more boxes of the flowchart. The computer program instructions can also be loaded on a computer or other programmable data processing device so that a series of operating steps are executed on a computer or other programmable device to produce a computer-implemented process, so that the instructions executed on a computer or other programmable device provide steps for realizing the function specified in one or more boxes of the flowchart.

[0061] In addition, each block of the flow chart may represent a portion, segment or module of code including 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 blocks may not appear in order. For example, depending on the functions involved, two blocks shown in succession may actually be executed simultaneously, or the blocks may sometimes be executed in reverse order.

[0062] As used herein, "unit" refers to a software element or hardware element that performs a predetermined function, such as a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC). However, the term "unit" does not always have a meaning limited to software or hardware. "Unit" can be constructed to be stored in an addressable storage medium or to execute one or more processors. Therefore, "unit" includes, for example, software elements, object-oriented software elements, class elements or task elements, processes, functions, attributes, procedures, subroutines, segmentation of program code, drivers, firmware, microcodes, circuits, data, databases, data structures, tables, arrays and parameters. The elements and functions provided by "unit" can be combined into a smaller number of elements or "units", or divided into a larger number of elements or "units". In addition, elements and "units" can be implemented as duplicating one or more CPUs in a device or a secure multimedia card. In addition, in an embodiment, the term "unit" can include one or more processors.

[0063] Wireless communication systems have evolved toward broadband wireless communication systems that provide high-speed and high-quality packet data services according to communication standards such as High Speed ​​Packet Access (HSPA) of the 3rd Generation Partnership Project (3GPP), LTE or Evolved Universal Terrestrial Radio Access (E-UTRA), Advanced LTE (LTE-A), LTE-Pro, High Speed ​​Packet Data (HRPD) of 3GPP2, Ultra Mobile Broadband (UMB), 802.16e of the Institute of Electrical and Electronics Engineers (IEEE) that goes beyond initially provided voice-based services, and the like.

[0064] As a representative example of a broadband wireless communication system, the LTE system adopts an orthogonal frequency division multiplexing (OFDM) scheme for a downlink (DL) (the term "downlink" and the term "DL" are used interchangeably throughout the disclosure), and adopts a single carrier frequency division multiple access (SC-FDMA) scheme for an uplink (UL) (the term "uplink" and the term "UL" are used interchangeably throughout the disclosure). The uplink is a radio link through which a UE (or MS) sends data or a control signal to a BS (or eNode B), and the downlink is a radio link through which a BS sends data or a control signal to a UE. In the multiple access scheme as described above, time-frequency resources for carrying data or control information are allocated and operated in a manner to prevent resource overlap, that is, orthogonality is established between users so that the data or control information of each user is identified.

[0065] The post-LTE communication system, namely the 5G communication system, should be able to freely reflect the various needs of users and service providers, and therefore needs to support services that meet various needs. The services considered for the 5G communication system include enhanced mobile broadband (eMBB), massive machine type communication (mMTC), and ultra-reliable low latency communication (URLLC).

[0066] eMBB is intended to provide improved data transmission rates in order to exceed the data transmission speeds supported by conventional LTE, LTE-A or LTE-Pro. For example, in a 5G communication system, from the perspective of a BS, eMBB should provide a peak downlink data rate of 20 gigabits per second (Gbps) and a peak uplink data rate of 10Gbps. In addition, the 5G communication system should provide not only peak data rates, but also increased user-perceived data rates. In order to meet these requirements, it is necessary to improve various transmission / reception technologies, including further improved multiple-input multiple-output (MIMO) transmission technologies. In addition, while the current LTE system uses a transmission bandwidth ranging from a bandwidth of 2 GHz to a maximum bandwidth of 20 megahertz (MHz) to transmit signals, the 5G communication system uses a frequency bandwidth wider than 20 MHz in a frequency band of 3 to 6 GHz or higher than or equal to 6 GHz, thereby meeting the data transmission rate required by the 5G communication system.

[0067] In addition, in order to support application services such as IoT, mMTC is considered in the 5G communication system. In order to effectively provide IoT technology, mMTC needs to support the access of multiple UEs in a cell, improve UE coverage, increase battery life, and reduce UE costs. IoT technology is used in conjunction with various sensors and devices to provide communication, so a large number of UEs in a cell (for example, per square km (km 2 )1000000 UEs). Since mMTC-enabled UEs are likely to be located in shadow areas that cannot be covered by the cell due to service characteristics, such as the basement of a building, mMTC may require wider coverage than other services provided by the 5G communication system. mMTC-enabled UEs need to be produced at low cost, and it is difficult to replace their batteries frequently. Therefore, a long battery life, such as 10 to 15 years, may be required.

[0068] URLLC is a cellular-based wireless communication service for specific (mission-critical) purposes. For example, services for remote control of robots or machines, industrial automation, unmanned aerial vehicles, remote healthcare, and emergency alerts can be considered. Therefore, the communication provided by URLLC should provide very low latency and very high reliability. For example, services supporting URLLC should meet a radio access delay time (air interface delay) shorter than 0.5 milliseconds, and also require a packet error rate equal to or less than 10-5. Therefore, for services supporting URLLC, 5G systems should provide a smaller transmission time interval (TTI) than other systems, and also have design requirements for allocating a wide array of resources in the frequency band in order to ensure the reliability of the communication link.

[0069] The three services of 5G, namely eMBB, URLLC and mMTC, can be multiplexed and transmitted in one system. At this time, in order to meet the different requirements of each service, different transmission / reception schemes and transmission / reception parameters can be used for the service. Of course, 5G is not limited to the above three services.

[0070] [NR time-frequency resources]

[0071] Hereinafter, the frame structure of the 5G system is described in more detail with reference to the accompanying drawings.

[0072] 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.

[0073] exist Figure 1 In the figure, the horizontal axis indicates the time domain and the vertical axis indicates the frequency domain. The basic unit of resources in the time and frequency domain is a resource element (RE) 101, and 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, (eg, 12) consecutive REs may correspond to one resource block (RB) 104.

[0074] Figure 2 The structure of frames, subframes, and time slots in a wireless communication system according to an embodiment of the present disclosure is shown.

[0075] exist Figure 2 , an example of the structure of a frame 200, a subframe 201, and a time slot 202 is shown. One frame 200 may be defined as 10 milliseconds (ms). One subframe 201 may be defined as 1 ms, and thus, one frame 200 may include a total of 10 subframes 201. One time slot 202 or 203 may be defined as 14 OFDM symbols (i.e., the number of symbols per time slot). ). One subframe 201 may include one or more time slots 202 and 203, and the number of time slots 202 or 203 per subframe 201 may vary depending on the configured value μ 204 or 205 of the subcarrier spacing. Figure 2 204 is a case where the subcarrier spacing configuration value 204 is μ=0 and a case where the subcarrier spacing configuration value 205 is μ=1. In the case where μ=0 204, one subframe 201 may include one time slot 202, and in the case where μ=1 205, one subframe 201 may include two time slots 203. That is, the number of time slots per subframe is can vary depending on the configured value of the subcarrier spacing (μ), and accordingly, the number of time slots per frame The number of subcarrier spacing configuration values ​​μ can also vary. and quantity It can be defined as shown in Table 1 below.

[0076] [Table 1]

[0077]

[0078] [Bandwidth Part (BWP)]

[0079] Subsequently, a configuration of a bandwidth part (BWP) in a 5G system is described in detail with reference to the accompanying drawings.

[0080] Figure 3 An example of bandwidth portion configuration in a wireless communication system according to an embodiment of the present disclosure is shown.

[0081] exist Figure 3 In FIG. 3 , the UE bandwidth 300 is configured into two bandwidth parts, namely, BWP#1 301 and BWP#2 302. The BS may configure one or more BWPs in the UE, and the following information provided below in Table 2 may be configured to each BWP.

[0082] [Table 2]

[0083]

[0084] Of course, the present disclosure is not limited to the above examples, and various parameters and configuration information related to BWP can be configured in the UE. Information can be sent from the BS to the UE through high-level signaling (e.g., radio resource control (RRC) signaling). Among one or more configured BWPs, at least one BSP can be activated. Information indicating whether to activate the configured BWP can be semi-statically transmitted from the BS to the UE through RRC signaling, or can be dynamically transmitted through DCI.

[0085] The UE may receive the configuration of the initial BWP for initial access from the BS through the master information block (MIB) before the RRC connection. More specifically, the UE may receive configuration information of a CORESET (“CORESET” and “control resource set” are used interchangeably throughout the disclosure) and a search space (the term “search space” and the term “SS” are used interchangeably throughout the disclosure), wherein a PDCCH for receiving system information (remaining system information (RMSI) or system information block 1 (SIB1)) required for initial access through the MIB may be sent in the initial access step. The control resource set and search space configured as the MIB may be considered as identity (ID) 0. The BS may notify the UE of configuration information such as frequency allocation information, time allocation information, and parameter set for control resource set #0 through the MIB. In addition, the BS may notify the UE of configuration information of the monitoring period and timing of the control resource set #0, that is, configuration information of the search space #0, through the MIB. The UE may regard the frequency region configured as the control resource set #0 acquired from the MIB as the initial bandwidth portion for initial access. At this time, the ID of the initial BWP can be considered to be 0.

[0086] Configuration of the BWP supported by the 5G system can be used for various purposes.

[0087] When the bandwidth supported by the UE is narrower than the system bandwidth, it can be supported by BWP configuration. For example, the BS can configure the frequency position of the BWP in the UE (configuration information 2), so that the UE can send and receive data at a specific frequency position within the system bandwidth.

[0088] In addition, in order to support different parameter sets, the BS can configure multiple BWPs in the UE. For example, in order to support the UE to perform data transmission and reception using both a subcarrier spacing of 15 kilohertz (kHz) and a subcarrier spacing of 30 kHz, two BWPs can be configured with subcarrier spacings of 15 kHz and 30 kHz, respectively. Different BWPs can be frequency-division multiplexed, and when data is to be sent and received at a specific subcarrier spacing, the BWP configured with the corresponding subcarrier spacing can be activated.

[0089] In order to reduce the power consumption of the UE, the BS can configure a BWP with different bandwidth sizes in the UE. When the UE supports a very large bandwidth, such as 100 MHz, but always sends and receives data through this bandwidth, very high power consumption may be generated. In particular, from the perspective of power consumption, it is very inefficient to monitor unnecessary downlink control channels through a large bandwidth of 100 MHz in a state without business. In order to reduce the power consumption of the UE, the BS can configure a BWP with a relatively narrow bandwidth (for example, 200 MHz). In a state without business, the UE can perform monitoring operations in a bandwidth portion of 200 MHz, and if data is generated, it can send and receive data through a bandwidth portion of 100 MHz according to instructions from the BS.

[0090] In the method of configuring BWP, the UE before RRC connection can receive configuration information of the initial bandwidth part through the MIB in the initial access step. More specifically, the UE can receive the configuration of the CORESET of the downlink control channel, where the DCI for scheduling the SIB can be sent from the MIB of the physical broadcast channel (PBCH). The bandwidth of the control resource set configured as the MIB can be regarded as the initial bandwidth part, and the UE can receive the PDSCH in which the SIB is transmitted through the configured initial bandwidth part. The initial BWP can be used not only to receive SIBs, but also for other system information (OSI), paging or random access (RA) (the term "random access" and the term "RA" are used interchangeably throughout the disclosure).

[0091] [BWP changes]

[0092] When one or more BWPs are configured in the UE, the BS may indicate the change (or switch or transition) of the BWP to the UE via the BWP indicator field in the DCI. Figure 3 In the embodiment, when the currently activated BWP of the UE is BWP#1 301, the BS indicates BWP#2 302 to the UE through a BWP indicator within the DCI, and the UE makes a BWP change to BWP#2 302 indicated by the BWP indicator within the received DCI.

[0093] As described above, since the DCI-based BWP change can be indicated by the DCI used to schedule PDSCH or PUSCH, if the UE receives a BWP change request, the UE should be able to receive or send the PDSCH or PUSCH scheduled by the corresponding DCI in the changed BWP without any difficulty. To this end, the standard defines the requirement for the delay time (TBWP) required for the BWP change, which can be defined as shown in Table 3 below.

[0094] [Table 3]

[0095]

[0096]

[0097] According to the capability of the UE, the requirement for the BWP change delay time may support type 1 or type 2. The UE may report the supportable BWP delay time type to the BS.

[0098] When the UE receives a DCI including a BWP change indicator in time slot n according to the requirements of the BWP change delay time, the UE can complete the change to the new BWP indicated by the BWP change indicator at a time point no later than time slot n+TBWP, and send and receive the data channel scheduled by the corresponding DCI in the changed new BWP. When the BS expects to schedule the data channel in the new BWP, the BS can determine the time domain resource allocation of the data channel in consideration of the BWP change delay time (TBWP) of the UE. That is, when scheduling the data channel in the new BWP, the BS can schedule the corresponding data channel after the BWP change delay time using a method for determining the time domain resource allocation of the data channel. Therefore, the UE may not expect the DCI indicating the BWP change to indicate a time slot offset (K0 or K2) that is less than the BWP change delay time (TBWP).

[0099] If the UE receives a DCI indicating a BWP change (e.g., DCI format 1_1 or 0_1), the UE may not perform transmission or reception during a time interval from the third symbol of the slot for receiving the PDCCH including the corresponding DCI to the start point of the slot indicated by the slot offset (K0 or K2) indicated by the time domain resource allocation field within the corresponding DCI. For example, when the UE receives a DCI indicating a BWP change in slot n and the slot offset value indicated by the corresponding DCI is K, the UE does not perform transmission or reception from the third symbol of slot n to the symbol before slot n+K (i.e., the last symbol of slot n+K-1).

[0100] [SS / PBCH block]

[0101] Subsequently, the synchronization signal / PBCH block in the 5G system is described.

[0102] The synchronization signal / PBCH block may be a physical layer channel block including a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a PBCH. A detailed description thereof is given below.

[0103] -PSS is a signal that serves as a reference for downlink time / frequency synchronization and provides some information of the cell ID.

[0104] -SSS is a reference for downlink time / frequency synchronization and provides the remaining cell ID information not provided by PSS. In addition, SSS is used as a reference signal for demodulation of PBCH.

[0105] -PBCH provides necessary system information required for UE to transmit and receive data channels and control channels. Necessary system information may include search space-related control information indicating radio resource mapping information of control channels and scheduling control information of a separate data channel for transmitting system information.

[0106] - A synchronization signal / PBCH block includes a combination of PSS, SSS and PBCH. One or more synchronization signal / PBCH blocks may be transmitted within a time of 5 ms, and each of the transmitted synchronization signal / PBCH blocks may be separated by an index.

[0107] The UE can detect the PSS and SSS in the initial access phase and decode the PBCH. The UE can obtain the MIB from the PBCH and receive the configuration of CORESET#0 (corresponding to the control resource set with the control resource set index 0) therefrom. The UE can monitor the control resource set #0 based on the assumption that the selected SS / PBCH block and the demodulation reference signal (DMRS) sent in the control resource set #0 are quasi-co-located (QCL). The UE can receive system information through the downlink control information sent in the control resource set #0. The UE can obtain the 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 BS taking into account the selected synchronization signal / PBCH block index, and the BS receiving the PRACH can obtain the synchronization signal / PBCH block index selected by the UE. The BS can know which block the UE has selected from the synchronization signal / PBCH block, and the CORESET#0 related to it is monitored.

[0108] [PDCCH: related to DCI]

[0109] Subsequently, DCI in the 5G system will be described in detail.

[0110] In the 5G system, scheduling information for uplink data (or physical uplink data channel (PUSCH)) or downlink data (or physical downlink data channel (PDSCH)) is sent from the BS to the UE through DCI. The UE can monitor the fallback DCI format and non-fallback DCI format of PUSCH or PDSCH. The fallback DCI format may include a fixed field predefined between the BS and the UE, and the non-fallback DCI format may include a configurable field.

[0111] DCI can be sent via PDCCH via a channel coding and modulation process. A cyclic redundancy check (CRC) can be attached to the DCI message payload and can be scrambled by a radio network temporary identifier (RNTI) corresponding to the identity of the UE. Different RNTIs can be used depending on the purpose of the DCI message, for example, UE-specific data transmission, power control commands, or random access responses. That is, the RNTI may not be sent explicitly, but may be sent when included in the CRC calculation process. If a DCI message sent via PDCCH is received, the UE can identify the CRC by the assigned RNTI, and when the CRC is determined to be correct based on the CRC identification result, it can be identified that the corresponding message is sent to the UE.

[0112] For example, the DCI for scheduling PDSCH for system information (SI) can be scrambled by SI-RNTI. The DCI for scheduling PDSCH for random access response (RAR) message can be scrambled by RA-RNTI. The DCI for scheduling PDSCH for paging message can be scrambled by P-RNTI. The DCI for notifying slot format indicator (SFI) can be scrambled by SFI-RNTI. The DCI for notifying transmit power control (TPC) can be scrambled by TPC-RNTI. The DCI for scheduling UE-specific PDSCH or PUSCH can be scrambled by cell RNTI (C-RNTI).

[0113] DCI format 0_0 may be used for fallback DCI scheduling PUSCH, in which case the CRC may be scrambled by the C-RNTI. DCI format 0_0 in which the CRC is scrambled by the C-RNTI may include the following information, such as shown in Table 4.

[0114] [Table 4]

[0115]

[0116] DCI format 0_1 ​​may be used for scheduling non-fallback DCI for PUSCH, in which case the CRC may be scrambled by the C-RNTI. DCI format 0_1 ​​in which the CRC is scrambled by the C-RNTI may include the following information, such as shown in Table 5 below.

[0117] [Table 5]

[0118]

[0119]

[0120] DCI format 1_0 may be used for fallback DCI scheduling PDSCH, in which case the CRC may be scrambled by the C-RNTI. DCI format 1_0 in which the CRC is scrambled by the C-RNTI may include the following information, such as shown in Table 6 below.

[0121] [Table 6]

[0122]

[0123] DCI format 1_1 may be used for scheduling non-fallback DCI for PDSCH, in which case the C-RNTI may be scrambled by the CRC. DCI format 1_1 in which the CRC is scrambled by the C-RNTI may include the following information, for example, as shown in Table 7 below.

[0124] [Table 7]

[0125]

[0126]

[0127] [PDCCH: CORESET, REG, CCE, search space]

[0128] Subsequently, a downlink control channel in a 5G communication system is described in more detail with reference to the accompanying drawings.

[0129] Figure 4 An example of the configuration of a control region of a downlink control channel in a wireless communication system according to an embodiment of the present disclosure is shown.

[0130] Figure 4 An example is shown in which a UE bandwidth part 410 is configured on the frequency axis, and a control resource set #1 401 and a control resource set #2 402 are configured in a time slot 420 on the time axis. The control resource sets 401 and 402 may be configured in a specific frequency resource 403 within the entire UE BWP 410 on the frequency axis. The control resource set may be configured as one or more OFDM symbols on the time axis, which may be defined as a control resource set duration 404. Figure 4 In the example shown in , control resource set #1 401 may be configured as a control resource set duration of 2 symbols, and control resource set #2 402 may be configured as a control resource set duration of 1 symbol.

[0131] The control resource set in the 5G system can be configured in the UE by the BS through high-level signaling (e.g., SIB, MIB, or RRC signaling). Configuring the control resource set in the UE may mean providing information such as the control resource set identity, the frequency location of the control resource set, and the symbol length of the control resource set. For example, the following information shown in Table 8 below may be included.

[0132] [Table 8]

[0133]

[0134]

[0135] In Table 8, tci-StatesPDCCH (referred to as transmission configuration indication (TCI) state) configuration information may include information about one or more synchronization signal / PBCH block indices or CSI-RS indices having a quasi co-location (QCL) relationship with a DMRS transmitted in the corresponding CORESET.

[0136] Figure 5A The structure of a downlink control channel in a wireless communication system according to an embodiment of the present disclosure is shown.

[0137] refer to Figure 5A , the basic unit of time and frequency resources included in the control channel may be a resource element group (REG) 503, and REG 503 may be defined as one OFDM symbol 501 on the time axis and one PRB 502 on the frequency axis, i.e., 12 subcarriers. The BS may configure the downlink control channel allocation unit by cascading REG 503.

[0138] like Figure 5A As shown in FIG. 1 , when the basic unit for allocating a downlink control channel in a 5G system is a control channel element (CCE) 504, one CCE 504 may include a plurality of REGs 503. Figure 5A Taking the description of REG 503 as an example, REG 503 may include 12 REs, and when 1 CCE 504 includes 5 REGs 503, 1 CCE 504 may include 72 REs. When a downlink CORESET is configured, the corresponding area may include multiple CCEs 504, and a specific downlink control channel may be mapped to one or more CCEs 504 according to an aggregation level (AL) within the CORESET and then transmitted. The CCEs 504 within the CORESET may be distinguished by numbering, and the numbers of the CCEs 504 may be assigned according to a logical mapping scheme.

[0139] Figure 5AThe basic unit of the downlink control channel shown in FIG. 5 , namely, REG 503, may include all REs to which DCI is mapped and an area to which DMRS 505, a reference signal for decoding REs, is mapped. Figure 5A As shown, 3 DMRS 505 can be sent in 1 REG 503. Depending on the aggregation level (AL), the number of CCEs required to send PDCCH can be 1, 2, 4, 8 or 15, and different numbers of CCEs can be used to implement link adaptation of the downlink control channel. For example, if AL=L, one downlink control channel can be sent through L CCEs. The UE should detect the signal in a state where the UE does not know the information about the downlink control channel, and the search space indicating the set of CCEs is defined to perform blind decoding in a wireless communication system (e.g., 5G or NR system). The search space is a set of downlink control channel candidates including CCEs, for which the UE should attempt to decode at a given aggregation level, and there are various aggregation levels on which a set of CCEs is configured by 1, 2, 4, 8 or 15 CCEs, so that the UE can have multiple search spaces. The search space set can be defined as a set of search spaces at all configured aggregation levels.

[0140] The search space can be classified into a common search space and a UE-specific search space. UEs in a predetermined group or all UEs can search the common search space of the PDCCH in order to receive cell common control information, such as paging messages or dynamic scheduling of system information. For example, PDSCH scheduling allocation information for the transmission of SIBs including information about the service provider of the cell can be received by searching (monitoring) the common search space of the PDCCH. In the case of a common search space, UEs in a predetermined group or all UEs should receive the PDCCH so that the common search space can be defined as a set of pre-scheduled CCEs. Scheduling allocation information for UE-specific PDSCH or PUSCH can be received by searching the UE-specific search space of the PDCCH. The UE-specific search space can be UE-specifically defined as a function of the UE identity and various system parameters.

[0141] The parameters of the search space for PDCCH in a wireless communication system (e.g., 5G or NR system) can be configured in the UE by the BS through high-level signaling (e.g., SIB, MIB, or RRC signaling). For example, the BS can configure the number of PDCCH candidates at each aggregation level L, the monitoring period of the search space, the monitoring timing in units of symbols within the time slot for the search space, the search space type (i.e., a common search space or a UE-specific search space), the combination of RNTI and DCI format to be monitored in the corresponding search space, and the control resource set index for monitoring the search space, etc. For example, the following information shown in Table 9 below may be included in the information configured by the BS.

[0142] [Table 9]

[0143]

[0144]

[0145]

[0146] The BS may configure one or more search space sets in the UE according to the configuration information. The BS may configure search space set 1 and search space set 2 in the UE, and the configuration may be performed so that DCI format A scrambled by X-RNTI (e.g., first RNTI) in search space set 1 is monitored in the common search space, and DCI format B scrambled by Y-RNTI (e.g., second RNTI) in search space set 2 is monitored in the UE-specific search space.

[0147] According to the configuration information, one or more search space sets may exist in a common search space or a UE-specific search space. For example, search space set #1 and search space set #2 are configured as common search spaces, and search space set #3 and search space set #4 may be configured as UE-specific search spaces.

[0148] In the common search space, the following combinations of DCI formats and RNTIs may be monitored. Of course, the present disclosure is not limited to the following examples.

[0149] - DCI format 0_0 / 1_0 with CRC scrambled by Cell-RNTI (C-RNTI), Configured Scheduling (CS)-RNTI, Semi-Persistent (SP)-CSI-RNTI, RA-RNTI, Temporary Cell (TC)-RNTI, Paging (P)-RNTI and System Information (SI)-RNTI;

[0150] - DCI format 2_0 with CRC scrambled by SFI-RNTI;

[0151] -DCI format 2_1 with CRC scrambled by interrupt (INT)-RNTI;

[0152] -DCI format 2_2 with CRC scrambled by TPC-PUSCH-RNTI and TPC-PUCCH-RNTI; and

[0153] -DCI format 2_3 with CRC scrambled by TPC-SRS-RNTI.

[0154] In the UE-specific search space, the following combinations of DCI formats and RNTIs may be monitored. Of course, the present disclosure is not limited to the following embodiments.

[0155] - DCI format 0_0 / 1_0 with CRC scrambled by C-RNTI, CS-RNTI and TC-RNTI; and

[0156] -DCI format 1_0 / 1_1 with CRC scrambled by C-RNTI, CS-RNTI, TC-RNTI.

[0157] The RNTI described may follow the following definition and usage.

[0158] -C-RNTI: used to schedule UE-specific PDSCH;

[0159] -TC-RNTI: used for UE-specific PDSCH scheduling;

[0160] -CS-RNTI: used for semi-statically configured UE-specific PDSCH scheduling;

[0161] RA-RNTI: used for PDSCH scheduling in the random access phase;

[0162] P-RNTI: used for scheduling the PDSCH through which paging is sent;

[0163] -SI-RNTI: used for PDSCH scheduling through which system information is sent;

[0164] -INT-RNTI: used to indicate whether puncture is performed on PDSCH;

[0165] -TPC RNTI for PUSCH (TPC-PUSCH-RNTI): used to indicate PUSCH power control command;

[0166] -TPC RNTI for PUCCH (TPC-PUCCH-RNTI): used to indicate PUCCH power control commands;

[0167] -TPC RNTI for SRS (TPC-SRS-RNTI): used to indicate an SRS power control command.

[0168] The DCI format may follow the following definition shown in Table 10 below.

[0169] [Table 10]

[0170]

[0171] The search space of aggregation level L in a control resource set p and a search space set s in a wireless communication system (e.g., a 5G or NR system) may be expressed as in Equation 1 below.

[0172] [Equation 1]

[0173]

[0174] -L: aggregation level

[0175] -n CI : Carrier index

[0176] -N pCe,p : The total number of CCEs in the control resource set p

[0177] - Time slot index

[0178] - Number of PDCCH candidates at aggregation level L

[0179] - PDCCH candidate index at aggregation level L

[0180] -i=0,…,L-1

[0181] - Y p,-1 =n RNTI ≠0,

[0182] A p =39827 for pmod3=0, A p = 39829 for pmod3 = 1,

[0183] A p =39839 for pmod3=2, D=65537.

[0184] -n RNNl : Terminal identity

[0185] In the case of a common search space, the value Can correspond to 0.

[0186] In case of UE-specific search space, the value It may correspond to a value that changes according to the identity of the UE (C-RNTI or ID configured by the base station for the UE) and the time index.

[0187] In a wireless communication system (e.g., a 5G or NR system), multiple search space sets can be configured with different parameters (e.g., the parameters in Table 9), so the set of search space sets monitored by the UE at each time point can vary. When search space set #1 is configured on an X time slot cycle, search space set #2 is configured on a Y time slot cycle, and X and Y are different from each other. The UE can monitor all search space sets #1 and search space sets #2 in a specific time slot, and monitor one of search space sets #1 and search space sets #2 in another specific time slot.

[0188] [PDCCH: span]

[0189] In the case where there are multiple PDCCH monitoring positions within a time slot, the UE can report the UE capability, at which point the concept "span" can be used. A span is a continuous symbol in which the UE can monitor the PDCCH within a time slot, and each PDCCH monitoring position can be within 1 span. A span can be represented by (X, Y), where X refers to the minimum number of symbols that should be spaced between the first symbols of two consecutive spans, and Y refers to the number of consecutive symbols used to monitor the PDCCH within one span. At this point, the UE can monitor the PDCCH in a portion within Y symbols starting from the first symbol of the span within the span.

[0190] Figure 5B It is shown that a UE in a wireless communication system according to an embodiment of the present disclosure may have multiple PDCCH monitoring positions within a time slot through a span.

[0191] refer to Figure 5B , the span is represented by (X, Y) = (7, 3), (4, 3) and (2, 2), and these three cases are Figure 5B In the example, 5-1-05 indicates that the total number of spans that can be represented by (4, 3) is 3 in the time slot, and the interval between the second span and the third span is X'=5 symbols, which is greater than X=4.

[0192] [PDCCH: UE capability report]

[0193] The slot positions of the common search space and the UE-specific search space are indicated by the monitoringSymbolsWithinSlot parameter in Table 11-1, as shown below, and the symbol positions within the slot are indicated by the bitmap through the monitoringSymbolsWithinSlot parameter in Table 9, as shown above. At the same time, the symbol positions within the slot where the UE can perform search space monitoring can be reported to the BS through the following UE capabilities.

[0194] -UE capability 1 (hereinafter referred to as "FG 3-1") will now be described. When the number of monitoring opportunities (MO) (the term "monitoring opportunity" and the term "MO" are used interchangeably throughout the disclosure) for type 1 and type 3 search spaces or UE-specific search spaces within a slot is 1, as shown in the following Table 11-1, if the corresponding MO is within the first 3 symbols of the slot, the UE capability is the ability to monitor the corresponding MO. The UE capability is a mandatory capability that all UEs supporting NR should support, and whether the capability is supported is not explicitly reported to the BS.

[0195] [Table 11-1]

[0196]

[0197]

[0198]

[0199] -UE capability 2 (hereinafter referred to as "FG 3-2") will now be described. When the number of MOs for a common search space or a UE-specific search space within a slot is one, as shown in Table 11-2 below, the UE capability is the ability to perform monitoring regardless of the start symbol position of the corresponding MO. The UE capability may be optionally supported by the UE, and whether the capability is supported is explicitly reported to the BS.

[0200] [Table 11-2]

[0201]

[0202] -UE capability 3 (hereinafter referred to as "FG 3-5", "FG 3-5a", "FG 3-5b") will now be described. When the number of MOs for a common search space or a UE-specific search space within a slot is multiple, as shown in Table 11-3 below, the UE capability indicates a pattern of MOs that the UE can monitor. The pattern includes an interval X between start symbols of different MOs and a maximum symbol length Y of one MO. The combination of (X, Y) supported by the UE can be one or more of {(2, 2), (4, 3), (7, 3)}. The UE capability may be optionally supported by the UE, and whether the capability is supported and the combination (X, Y) are explicitly reported to the BS.

[0203] [Table 11-3]

[0204]

[0205]

[0206]

[0207]

[0208]

[0209] The UE may report to the BS whether it supports UE capability 2 and / or UE capability 3 and related parameters. The BS may allocate timeline resources for common search space and UE-specific search space based on UE capabilities. In resource allocation, the BS may not place the MO in a location where the UE cannot perform monitoring.

[0210] [PDCCH: BD / CCE restriction]

[0211] If multiple search space sets are configured in the UE, the method of determining the search space set that the UE should monitor can be based on "Condition 1" and "Condition 2".

[0212] If the UE receives a configuration of a value of monitoringCapabilityConfig-r16 as high-layer signaling of r15monitoringcapability, the UE defines the maximum value of the number of PDCCH candidates that can be monitored and the number of CCEs included in the entire search space (indicating the set of entire CCE sets corresponding to the joint area of ​​multiple search space sets). When the UE receives a configuration of a value of monitoringCapabilityConfig-r16 as r16monitoringcapability, the UE may define the maximum value of the number of PDCCH candidates that can be monitored and the number of CCEs included in the entire search space (indicating the set of entire CCE sets corresponding to the joint area of ​​multiple search space sets) for each span.

[0213] [Condition 1: Restriction on the maximum number of PDCCH candidates]

[0214] The subcarrier spacing is configured as 15±2 μ kHz cell, when the maximum number of PDCCH candidates M is defined based on the time slot μ As described above, the maximum number of PDCCH candidates that the UE can monitor according to the configuration value of the higher layer signaling is M. μ Following Table 12-1 as shown below, or when the maximum number of PDCCH candidates M is defined based on the span μ , it follows the table 12-2 shown below.

[0215] [Table 12-1]

[0216]

[0217] [Table 12-2]

[0218]

[0219] [Condition 2: Limitation on the maximum number of CCEs]

[0220] The subcarrier spacing is configured as 15±2 μ kHz cell, as described above, when the maximum number of CCEs is defined based on the time slot, C μ When the maximum number of CCEs included in the entire search space (indicating the set of the entire CCE set corresponding to the joint area of ​​multiple search space sets) according to the configuration value of the higher layer signaling is μ Follow Table 12-3, or when the maximum number of CCEs is defined based on the span C μ , follow the table 12-4 shown below.

[0221] [Table 12-3]

[0222]

[0223] [Table 12-4]

[0224]

[0225] For convenience of description, a case where both conditions 1 and 2 are satisfied at a certain point in time is defined as “condition A.” Therefore, failure to satisfy condition A may mean that at least one of conditions 1 and 2 is not satisfied.

[0226] [PDCCH: Overbooking]

[0227] According to the configuration of the search space set by the BS, condition A may not be satisfied at a specific time point. If condition A is not satisfied at a specific time point, the UE may select and monitor only some search space sets configured to satisfy condition A at the corresponding time point, and the BS may transmit the PDCCH through the selected search space set.

[0228] The following method can be used as a way to select some configured set of search spaces.

[0229] If condition A for PDCCH is not met at a specific time point (time slot), the UE (or BS) may give priority to the search space set whose search space type is configured as a UE-specific search space, and select a search space set whose search space type is configured as a common search space from among the search space sets existing at the corresponding time point.

[0230] If all search space sets configured as common search spaces are selected (i.e., if condition A is satisfied even after all search spaces configured as common search spaces are selected), the UE (or BS) may select a search space set configured as a UE-specific search space. At this time, if the number of search space sets configured as UE-specific search spaces is multiple, a search space set with a lower search space set index may have a higher priority. The UE-specific search space set may be selected within the range of satisfying condition A in consideration of the priority.

[0231] [Discontinuous Reception (DRX)]

[0232] Figure 6 An example of a DRX operation in a wireless communication system according to an embodiment of the present disclosure is shown.

[0233] DRX is an operation in which a UE using a service receives data discontinuously in an RRC connection state in which a radio link is established between a BS and a UE. When DRX is applied, the UE may turn on a receiver at a specific time point and monitor a control channel, and when no data is received for a predetermined period, turn off the receiver to reduce the power consumption of the UE. The DRX operation may be controlled by a MAC layer device based on various parameters and timers.

[0234] refer to Figure 6 , the active time 605 is the time during which the UE wakes up and monitors the PDCCH in each DRX cycle. The active time 605 can be defined as follows:

[0235] - drx-onDurationTimer (drx-onDurationTimer) or drx-InactivityTimer (drx-inactivity timer) or drx-RetransmissionTimerDL (drx-retransmission timer DL) or drx-RetransmissionTimerUL (drx-retransmission timer UL) or ra-ContentionResolutionTimer (ra-contention resolution timer) is running;

[0236] - a scheduling request is issued on the PUCCH and is pending; or

[0237] - After successfully receiving a random access response to a random access preamble that is not selected by the MAC entity from among the contention-based random access preambles, a PDCCH indicating a new transmission addressed to the C-RNTI of the MAC entity is not received.

[0238] drx-onDurationTimer, drx-InactivityTimer, drx-RetransmissionTimerDL, drx-RetransmissionTimerUL, and ra-ContentionResolutionTimer are timers whose values ​​are configured by the BS, and have a function configured to monitor the PDCCH by the UE in a state where a predetermined condition is satisfied.

[0239] drx-onDurationTimer 615 is a parameter for configuring the minimum time that the UE wakes up in the DRX cycle. drx-InactivityTimer 620 is a parameter for configuring the time that the UE additionally wakes up when a PDCCH indicating a new uplink transmission or downlink transmission is received (as shown in reference numeral 630). drx-RetransmissionTimerDL is a parameter for configuring the maximum time that the UE wakes up in the downlink hybrid automatic repeat request (HARQ) process to receive downlink retransmissions. drx-RetransmissionTimerUL is a parameter for configuring the maximum time that the UE wakes up in the uplink HARQ process to receive a grant for uplink retransmissions. drx-onDurationTimer, drx-InactivityTimer, drx-RetransmissionTimerDL and drx-RetransmissionTimerUL can be configured as, for example, time, the number of subframes and the number of time slots. ra-ContentionResolutionTimer is a parameter used to monitor the PDCCH during the random access procedure.

[0240] The inactive time 610 is a time when PDCCH monitoring is not performed or a time when PDCCH reception is not performed during the DRX operation, and the remaining time in the entire time when the DRX operation is performed except the active time 605. When the PDCCH is not monitored during the active time 605, the UE can enter a sleep or inactive state and reduce power consumption.

[0241] A DRX cycle refers to a cycle in which a UE wakes up and monitors a PDCCH. That is, a DRX cycle is a cycle of a time interval or duration from when a UE monitors a PDCCH to when it monitors the next PDCCH. There are two types of DRX cycles, such as a short DRX cycle and a long DRX cycle. A short DRX cycle may be optionally applied.

[0242] The long DRX cycle 625 is the longer cycle of the two DRX cycles configured in the UE. When the long DRX cycle operates, the UE starts the drx-onDurationTimer 615 at a time point when the long DRX cycle 625 passes after the starting point (e.g., the start symbol) of the drx-onDurationTimer 615. In the operation of the long DRX cycle 625, the UE may start the drx-onDurationTimer 615 in a time slot after the drx-SlotOffset (drx-time slot offset) in the subframe satisfying the following equation (2). Here, drx-SlotOffset is a delay before the drx-onDurationTimer 615 is started. The drx-SlotOffset may be configured as, for example, a time or the number of time slots.

[0243] [Equation 2]

[0244] [(SFN×10)+subframe number]modulo(drx-LongCycle(drx-long cycle))=drx-StartOffset(drx-start offset)

[0245] SFN refers to “Single Frequency Network.” drx-LongCycleStartOffset and drx-StartOffset may be used to define the subframe for starting the long DRX cycle 625. drx-LongCycleStartOffset may be configured, for example, as a time, a number of subframes, or a number of time slots.

[0246] [QCL, TCI status]

[0247] In a wireless communication system, one or more different antenna ports (or one or more channels, signals and combinations thereof, but for ease of description, generally referred to as different antenna ports) can be associated by the QCL configuration shown in Table 13 below. The TCI state notifies the QCL relationship between the PDCCH (or PDCCH DMRS) and another RS ​​or channel, and the reference antenna port A (e.g., reference RS#A) and another destination antenna port B (e.g., target RS#B) of the QCL means that the UE is allowed to apply some or all of the large-scale channel parameters estimated in antenna port A to the channel measurement from antenna port B. QCL needs to associate different parameters according to conditions, such as time tracking affected by average delay and delay spread, frequency tracking affected by Doppler shift and Doppler spread, radio resource management (RRM) affected by average gain, and beam management (BM) affected by spatial parameters. Accordingly, NR supports four types of QCL relationships, as shown in Table 13 below.

[0248] [Table 13]

[0249]

[0250] The spatial Rx parameters may refer to some or all of the angle of arrival (AoA), the power angular spectrum (PAS) of AoA, the angle of departure (AoD), the PAS of AoD, the transmit / receive channel correlation, the transmit / receive beamforming, and the spatial channel correlation.

[0251] As shown in Table 14 below, the QCL relationship can be configured in the UE through the RRC parameters TCI state and QCL information. Referring to Table 14 below, the BS can configure one or more TCI states in the UE and notify the UE of up to two QCL relationships (QCL-type 1 and QCL-type 2) for the RS (i.e., target RS) of the ID of the reference TCI state. At this time, each QCL information (QCL-information) included in the TCI state includes the BWP index and serving cell index of the reference RS indicated by the corresponding QCL information, the type and ID of the reference RS, and the QCL type, as shown in Table 13 above.

[0252] [Table 14]

[0253]

[0254] Figure 7 An example of BS beam allocation according to TCI state configuration in a wireless communication system according to an embodiment of the present disclosure is shown.

[0255] refer to Figure 7 , the BS can send information to the UE on N different beams through N different TCI states. N represents the number of beams or the number of TCI states. For example, when Figure 7 As shown, when N=3, the BS can notify that the qcl-type 2 parameters included in the three TCI states 700, 705 and 710 are associated with the CSI-RS or SSB corresponding to different beams to be configured as QCL type D, and the antenna ports referring to different TCI states 700, 705 and 710 are associated with different spatial Rx parameters (i.e., different beams).

[0256] The following Tables 15-1 to 15-5 show valid TCI state configurations according to the target antenna port type.

[0257] Table 15-1 shows a valid TCI state configuration when the target antenna port is a CSI-RS (TRS) for tracking. TRS is an NZP CSI-RS for which a repetition parameter is not configured among CSI-RSs and trs-Info is configured as true. The third configuration in Table 15-1 can be used for non-periodic TRS.

[0258] [Table 15-1]

[0259]

[0260] Table 15-2 shows a valid TCI state configuration when the target antenna port is a CSI-RS of CSI. The CSI-RS of CSI is an NZP CSI-RS for which a parameter indicating repetition (eg, a repetition parameter) is not configured among CSI-RSs and trs-Info is not configured to true.

[0261] [Table 15-2]

[0262]

[0263] Table 15-3 shows the valid TCI state configuration when the target antenna port is the CSI-RS of the BM (i.e., the same meaning as the CSI-RS reported by L1 RSRP). The CSI-RS of the BM is an NZP CSI-RS for which the repetition parameter is configured to have a value of on or off and trs-Info is not configured to true.

[0264] [Table 15-3]

[0265]

[0266] Table 15-4 shows the valid TCI state configuration when the target antenna port is PDCCH DMRS.

[0267] [Table 15-4]

[0268]

[0269] Table 15-5 shows the valid TCI state configuration when the target antenna port is PDCCH DMRS.

[0270] [Table 15-5]

[0271]

[0272]

[0273] In the representative QCL configuration methods of Tables 15-1 to 15-5, the target antenna port and the reference antenna port of each step are configured and operated as "SSB" -> "TRS" -> "CSI-RS of CSI, CSI-RS of BM, PDCCH DMRS or PDSCH DMRS". In the representative QCL configuration methods of Tables 20 to 24, the target antenna port and the reference antenna port of each step are configured and operated as "SSB" -> "TRS" -> "CSI-RS of CSI, CSI-RS of BM, PDCCH DMRS or PDSCH DMRS".

[0274] [PDCCH: related to TCI status]

[0275] The TCI state combinations applicable to the PDCCH DMRS antenna port are shown in the following Table 16. In Table 16, the fourth row is the combination assumed by the UE before RRC configuration, and configuration after RRC is impossible.

[0276] [Table 16]

[0277]

[0278] In a wireless communication system (e.g., a 5G system or an NR system), Figure 8 The hierarchical signaling approach shown is supported for dynamic allocation of PDCCH beams.

[0279] Figure 8 An example of a method of allocating TCI states for a PDCCH in a wireless communication system according to an embodiment of the present disclosure is shown.

[0280] refer to Figure 8 , the BS may configure N TCI states 805, 810, 815 ... 820 (800) in the UE through RRC signaling, and configure some of them as the TCI states of the CORESET, as indicated by reference numeral 825. Thereafter, the BS may indicate one of the TCI states 830, 835, and 840 of the CORESET to the UE through MAC CE signaling, as indicated by reference numeral 845. Subsequently, the UE may receive the PDCCH based on the beam information included in the TCI state indicated by the MAC CE signaling.

[0281] Fig. 9 The TCI indication MAC CE indication signaling structure for PDCCH DMRS in a wireless communication system according to an embodiment of the present disclosure is shown.

[0282] refer to Fig. 9, TCI indication MAC CE signaling for PDCCH DMRS may consist of 2 bytes (16 bits) and may include a 5-bit serving cell ID 915 , a 4-bit CORESET ID 920 , and a 7-bit TCI state ID 925 .

[0283] Fig.10 An example of CORESET and search space beam configuration in a wireless communication system according to an embodiment of the present disclosure is shown.

[0284] refer to Fig.10 , the BS may indicate one of the TCI state lists included in the configuration of the CORESET 1000 through MAC CE signaling, as shown in reference numeral 1005. Thereafter, before another TCI state is indicated to the corresponding CORESET through different MAC CE signaling, the UE may consider that the same QCL information (beam #1) 1005 is applied to one or more search spaces 1010, 1015, and 1050 associated with the CORESET. The PDCCH beam allocation method is difficult to indicate a beam change earlier than the MAC CE signaling delay, and has the disadvantage of applying the same beam to all CORESETs regardless of the search space characteristics, thereby causing flexible PDCCH beam operation to become difficult. Hereinafter, embodiments of the present disclosure provide a more flexible PDCCH beam configuration and operation method. In the following embodiments of the present disclosure, for the convenience of description, some different examples are provided, but they are not exclusive and may be applied by their appropriate combination according to the situation.

[0285] The BS may configure one or more TCI states for a specific CORESET in the UE, and activate one of the configured TCI states through a MAC CE activation command. For example, {TCI state #0, TCI state #1, TCI state #2} is configured as a TCI state in CORESET #1, and the BS may send a command to the UE through a MAC CE to activate TCI state #0 assumed to be the TCI state of CORESET #1. With the assistance of the activation command of the TCI state received through the MAC CE, the UE can correctly receive the DMRS of the corresponding CORESET based on the QCL information in the activated TCI state.

[0286] When the UE does not receive a MAC CE activation command for the TCI state of CORESET#0 with CORESET index 0, the UE may assume that the DMRS sent in CORESET#0 is QCL with the SS / PBCH blocks identified in the non-contention based random access procedure or initial access procedure not triggered by a PDCCH command.

[0287] When the UE does not receive configuration of the TCI state for CORESET#X or the UE receives configuration of one or more TCI states but does not receive a MAC CE activation command to activate one of them, the UE may assume that the DMRS sent in CORESET#X is QCL with the SS / PBCH blocks identified during the initial access procedure.

[0288] [PDCCH: related to QCL priority rules]

[0289] In the following description, an operation of determining the QCL priority of the PDCCH will be described in detail.

[0290] When multiple control resource sets in an activated bandwidth part that are operated by carrier aggregation in a single cell or frequency band and exist in a single or multiple cells overlap each other in the time domain and have the same or different QCL-type D characteristics in a specific PDCCH monitoring interval, the terminal can select a specific control resource set according to the QCL priority determination operation and monitor the control resource set having the same QCL-type D characteristics as the selected control resource set. That is, when multiple control resource sets overlap each other in the time domain, the terminal can receive only one QCL-type D characteristic. The criterion for determining the QCL priority may be as follows.

[0291] - Criterion 1. A set of control resources connected to a common search interval having a lowest index in a cell corresponding to a lowest index among cells including the common search interval

[0292] - Criterion 2. A control resource set connected to a terminal-specific search interval having a lowest index in a cell corresponding to a lowest index among cells including the terminal-specific search interval

[0293] As described above, if each criterion is not met, the next criterion is applied. For example, in the case where control resource sets overlap each other in the time domain in a specific PDCCH monitoring interval, if all control resource sets are connected to a terminal-specific search interval instead of a common search interval, that is, if criterion 1 is not met, the terminal can omit the application of criterion 1 and apply criterion 2.

[0294] When a control resource set is selected by the above criteria, the terminal may additionally consider the following two items for the QCL information configured in the control resource set. First, if control resource set 1 has CSI-RS1 as a reference signal having a QCL-type D relationship, the reference signal having a QCL-type D relationship with CSI-RS1 is SSB 1, and the reference signal having a QCL-type D relationship with control resource set 2 which is another control resource set is SSB 1, the terminal may consider that the two control resource sets 1 and 2 have different QCL-type D characteristics. Second, if control resource set 1 uses CSI-RS1 configured in cell 1 as a reference signal having a QCL-type D relationship, the reference signal having a QCL-type D relationship with CSI-RS1 is SSB1, and control resource set 2 uses CSI-RS2 configured in cell 2 as a reference signal having a QCL-type D relationship, and the reference signal having a QCL-type D relationship with CSI-RS2 is SSB 1, the terminal may consider that the two control resource sets have the same QCL-type D characteristics.

[0295] Fig.12 A diagram illustrating a method of selecting a receivable control resource set in consideration of a priority when a terminal receives a downlink control channel in a wireless communication system according to an embodiment of the present disclosure.

[0296] refer to Fig.12, the terminal may be configured to receive a plurality of control resource sets overlapping each other in the time domain in a specific PDCCH monitoring interval 1210, and each of the control resource sets may be connected to a common search space or a terminal-specific search space with respect to a plurality of cells. In the PDCCH monitoring interval, a control resource set #1 1215 connected to a common search interval #1 may exist in a bandwidth part #1 1200 of a cell #1, and a control resource set #1 1220 connected to a common search interval #1 and a control resource set #2 1225 connected to a terminal-specific search interval #2 may exist in a bandwidth part #1 1205 of a cell #2. The control resource sets 1215 and 1220 may have a QCL-type D relationship with a CSI-RS resource #1 configured in a bandwidth part #1 of a cell #1, and the control resource set 1225 may have a QCL-type D relationship with a CSI-RS resource #1 configured in a bandwidth part #1 of a cell #2. Therefore, if criterion 1 is applied to the PDCCH monitoring interval 1210, all other control resource sets having reference signals in the same QCL-type D as the control resource set #1 1215 may be received. Therefore, the terminal may receive the control resource sets 1215 and 1220 in the PDCCH monitoring interval 1210. As another example, the terminal may be configured to receive a plurality of control resource sets overlapping each other in the time domain in a specific PDCCH monitoring interval 1240, and each of the plurality of control resource sets may be connected to a common search space or a terminal-specific search space with respect to a plurality of cells. In the PDCCH monitoring interval, a control resource set #1 1245 connected to a terminal-specific search interval #1 and a control resource set #2 1250 connected to a terminal-specific search interval #2 may exist in a bandwidth part #1 1230 of a cell #1, and a control resource set #1 1255 connected to a terminal-specific search interval #1 and a control resource set #2 1260 connected to a terminal-specific search interval #3 may exist in a bandwidth part #1 1235 of a cell #2. The control resource sets 1245 and 1250 may have a QCL-type D relationship with a CSI-RS resource #1 configured in the bandwidth part #1 of the cell #1, the control resource set 1255 may have a QCL-type D relationship with a CSI-RS resource #1 configured in the bandwidth part #1 of the cell #2, and the control resource set 1260 may have a QCL-type D relationship with a CSI-RS resource #2 configured in the bandwidth part #1 of the cell #2. However, if criterion 1 is applied to the PDCCH monitoring interval 1240, there is no common search interval, so criterion 2 as the next criterion may be applied. If criterion 2 is applied to the PDCCH monitoring interval 1240, all other control resource sets having reference signals in the same QCL-type D as the control resource set 1245 may be received.Therefore, the terminal may receive control resource sets 1245 and 1250 in the PDCCH monitoring interval 1240 .

[0297] [Related to rate matching / puncturing]

[0298] Hereinafter, the rate matching operation and the puncturing operation will be described in detail.

[0299] If the time and frequency resource A in which the random symbol sequence A is to be transmitted overlaps with the random time and frequency resource B, the rate matching or puncturing operation may be considered as an operation of transmitting or receiving channel A in consideration of resource C (the region in which resource A and resource B overlap each other). The detailed operation may follow the following.

[0300] Rate Matching Operation

[0301] - The base station may transmit channel A after mapping channel A only to the remaining resource region of the entire resource A to which the base station will transmit the symbol sequence A to the terminal, the remaining resource region being obtained by excluding resource C corresponding to the region overlapping with resource B. For example, in the case where the symbol sequence A is configured by {symbol #1, symbol #2, symbol #3, symbol #4}, resource A is {resource #1, resource #2, resource #3, resource #4}, and resource B is {resource #3, resource #5}, the base station may transmit the symbol sequence A after sequentially mapping the symbol sequence A to the remaining resources {resource #1, resource #2, resource #4} obtained by excluding {resource #3} corresponding to resource C from resource A. Therefore, the base station may transmit the symbol sequence {symbol #1, symbol #2, symbol #3} after mapping the symbol sequence {symbol #1, symbol #2, symbol #3} to {resource #1, resource #2, resource #4}, respectively.

[0302] The terminal may determine resource A and resource B according to scheduling information about symbol sequence A from the base station, and may determine resource C, which is a region where resource A and resource B overlap each other, according to the scheduling information. The terminal may receive symbol sequence A under the assumption that symbol sequence A has been transmitted after being mapped to a remaining region obtained by excluding resource C from the entire resource A. For example, in the case where symbol sequence A is configured by {symbol #1, symbol #2, symbol #3, symbol #4}, resource A is {resource #1, resource #2, resource #3, resource #4}, and resource B is {resource #3, resource #5}, the terminal may receive symbol sequence A under the assumption that symbol sequence A has been sequentially mapped to remaining resources {resource #1, resource #2, resource #4} obtained by excluding {resource #3} corresponding to resource C from resource A. Therefore, the terminal may assume that the symbol sequence {symbol #1, symbol #2, symbol #3} has been transmitted after being respectively mapped to {resource #1, resource #2, resource #4}, and may thereafter perform a series of reception operations.

[0303] Deletion operation

[0304] If resource C corresponding to a region overlapping with resource B exists in the entire resource A to which the base station is to transmit a symbol sequence A to the terminal, the base station may map the symbol sequence A to the entire resource A, may not perform transmission in the resource region corresponding to resource C, and may perform transmission only in the remaining resource region obtained by excluding resource C from resource A. For example, in the case where symbol sequence A is configured by {symbol #1, symbol #2, symbol #3, symbol #4}, resource A is {resource #1, resource #2, resource #3, resource #4}, and resource B is {resource #3, resource #5}, the base station may map the symbol sequence A {symbol #1, symbol #2, symbol #3, symbol #4} to resource A {resource #1, resource #2, resource #3, resource #4}, respectively, may transmit only the symbol sequence {symbol #1, symbol #2, symbol #4} corresponding to the remaining resources {resource #1, resource #2, resource #4} obtained by excluding {resource #3} corresponding to resource C from resource A, and may not transmit {symbol #3} mapped to {resource #3} corresponding to resource C. 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.

[0305] The terminal can determine resource A and resource B according to scheduling information about symbol sequence A from the base station, and can determine resource C, which is a region where resource A and resource B overlap each other, through the scheduling information. Under the assumption that symbol sequence A has been mapped to the entire resource A but is transmitted only in the remaining region obtained by excluding resource C from resource region A, the terminal can receive symbol sequence A. For example, in the case where the symbol sequence A is configured by {symbol #1, symbol #2, symbol #3, symbol #4}, resource A is {resource #1, resource #2, resource #3, resource #4}, and resource B is {resource #3, resource #5}, the terminal may assume that the symbol sequence A {symbol #1, symbol #2, symbol #3, symbol #4} is mapped to resource A {resource #1, resource #2, resource #3, resource #4}, respectively, but {symbol #3} mapped to {resource #3} corresponding to resource C is not transmitted, and may perform reception under the assumption that the symbol sequence {symbol #1, symbol #2, symbol #4} corresponding to the remaining resource {resource #1, resource #2, resource #4} obtained by excluding {resource #3} corresponding to resource C from resource A has been mapped and transmitted. Therefore, the terminal may assume that the symbol sequence {symbol #1, symbol #2, symbol #4} has been transmitted after being mapped to {resource #1, resource #2, resource #4}, respectively, and may thereafter perform a series of reception operations.

[0306] Hereinafter, a method for configuring rate matching resources will be described for rate matching of a 5G communication system. Rate matching means adjusting the size of a signal taking into account the amount of resources available for transmission of the signal. For example, rate matching of a data channel may mean that the data channel is not transmitted after being mapped to a specific time and frequency resource area, and the size of the data is adjusted accordingly.

[0307] Fig.11 A diagram illustrating a method in which a base station and a terminal transmit or receive data in consideration of a downlink data channel and a rate matching resource.

[0308] Fig.11A downlink data channel (PDSCH) 1101 and a rate matching resource 1102 are shown. The base station can configure one or more rate matching resources 1102 for the terminal through high-layer signaling (e.g., RRC signaling). The configuration information about the rate matching resource 1102 may include time domain resource allocation information 1103, frequency domain resource allocation information 1104, and period information 1105. In the following description, the bitmap corresponding to the frequency domain resource allocation information 1104 is referred to as a "first bitmap", the bitmap corresponding to the time domain resource allocation information 1103 is referred to as a "second bitmap", and the bitmap corresponding to the period information 1105 is referred to as a "third bitmap". If all or part of the time and frequency resources of the scheduled data channel 1101 overlap with the configured rate matching resource 1102, the base station can perform rate matching of the data channel 1101 in the portion of the rate matching resource 1102 and transmit the data channel, and the terminal can perform reception and decoding after assuming that the data channel 1101 has been rate matched in the portion of the rate matching resource 1102.

[0309] The base station can dynamically inform the terminal whether to perform rate matching of the data channel in the configured rate matching resource part by means of additional configuration (which corresponds to the "rate matching indicator" in the above-mentioned DCI format) through DCI. Specifically, the base station can select some of the configured rate matching resources and group the selected resources into rate matching resource groups, and can indicate to the terminal whether the data channel is rate matched for each rate matching resource group by using a bitmap scheme through DCI. For example, if four rate matching resources of RMR#1, RMR#2, RMR#3 and RMR#4 are configured, the base station can configure RMG#1={RMR#1, RMR#2} and RMG#2={RMR#3, RMR#4} as rate matching groups, and indicate to the terminal whether rate matching is performed in RMG#1 and RMG#2 respectively through a bitmap by using two bits in the DCI field. For example, if rate matching is required, "1" can be indicated, and if rate matching is not required, "0" can be indicated.

[0310] 5G supports the granularity of "RB symbol level" and "RE level" as a method of configuring rate matching resources for the above terminals. More specifically, the following configuration method can be followed.

[0311] RB symbol level

[0312] A maximum of four RateMatchPattern (rate matching patterns) may be configured for each bandwidth part for the terminal through high-layer signaling, and one RateMatchPattern may include the following contents.

[0313] As reserved resources in the bandwidth part, such resources may be included, wherein the time and frequency resource regions of the reserved resources are configured by a combination of a bitmap with RB level in the frequency domain and a bitmap with symbol level. The reserved resources may span one or two time slots. A time domain pattern (periodicityAndPattern) may be additionally configured, wherein the time and frequency regions configured by each pair of RB level and symbol level bitmaps are repeated.

[0314] It may include time domain and frequency domain resource regions configured by a control resource set in a bandwidth part, and a resource region corresponding to a time domain pattern configured by configuring a search space in which a corresponding resource region is repeated.

[0315] RE Level

[0316] The following contents can be configured for the terminal through high-level signaling.

[0317] Configuration information (lte-CRS-ToMatchAround) about REs corresponding to LTE cell-specific reference signals or common reference signals (CRS) patterns may include the number of LTE CRS ports (nrofCRS-Ports) and the value of LTE-CRS-vshift (v-shift), information about the location of the center subcarrier of the LTE carrier from the frequency point (e.g., reference point A) used as a criterion (carrierFreqDL), information about the bandwidth size of the LTE carrier (carrierBandwidthDL), and subframe configuration information (mbsfn-SubframConfigList) corresponding to the Multicast-Broadcast Single-Frequency Network (MBSFN). The terminal can determine the location of the CRS in the NR time slot corresponding to the LTE subframe based on the above information.

[0318] Configuration information regarding resource sets corresponding to one or more zero-power (ZP) CSI-RS in a bandwidth portion may be included.

[0319] [Related to LTE CRS rate matching]

[0320] Next, the process of rate matching of the above-mentioned LTE CRS will be described in detail. For coexistence between long term evolution (LTE) and new RAT (NR), NR provides the NR terminal with the function of configuring the mode of cell-specific reference signals of LTE. More specifically, the CRS mode can be provided by RRC signaling, which includes at least one parameter in the ServingCellConfig (serving cell configuration) information element (IE) or the ServingCellConfigCommon (serving cell configuration common) IE. For example, the parameter can be lte-CRS-ToMatchAround, lte-CRS-PatternList1-r16, lte-CRS-PatternList2-r16, or crs-RateMatch-PerCORESETPoolIndex-r16.

[0321] Rel-15 NR provides the function of configuring one CRS pattern per serving cell through the lte-CRS-ToMatchAround parameter. Rel-16 NR extends this function so that the configuration of multiple CRS patterns per serving cell is possible. More specifically, one CRS pattern per LTE carrier can be configured for a terminal configured with a single transmit and receive point (TRP), and two CRS patterns per LTE carrier can be configured for a terminal configured with multiple TRPs. For example, a maximum of three CRS patterns per serving cell can be configured for a single TRP (single TPR) configuration terminal through the lte-CRS-PatternList1-r16 parameter. As another example, a CRS for each TRP can be configured for a terminal configured with multiple TRPs. That is, the CRS pattern for TRP1 can be configured for the lte-CRS-PatternList1-r16 parameter, and the CRS pattern for TRP2 can be configured through the lte-CRS-PatternList2-r16 parameter. In the case where two TRPs are configured as described above, whether the CRS patterns of both TRP1 and TRP2 are applied to a specific physical downlink shared channel (PDSCH) or only the CRS pattern of one TRP is applied is determined by the crs-RateMatch-PerCORESETPoolIndex-r16 parameter. When crs-RateMatch-PerCORESETPoolIndex-r16 is configured to be enabled, only the CRS pattern of one TRP is applied, otherwise, the CRS patterns of both TRPs are applied.

[0322] Table 17 shows the ServingCellConfig IE including the CRS pattern, and Table 18 shows the RateMatchPatternLTE-CRS IE including at least one parameter of the CRS pattern.

[0323] [Table 17]

[0324]

[0325]

[0326] [Table 18]

[0327]

[0328] [PDSCH: related to frequency resource allocation]

[0329] Fig.13 An example of frequency-axis resource allocation of a PDSCH in a wireless communication system according to an embodiment of the present disclosure is shown.

[0330] Fig.13 Three frequency axis resource allocation methods of type 0 13-00, type 1 13-05, and dynamic switching 13-10 that can be configured by a high layer in a wireless communication system (e.g., a 5G system or an NR system) are shown

[0331] refer to Fig.13 , when the UE is configured to use only resource type 0 through high-level signaling, as shown in reference numeral 13-00, some DCIs for allocating PDSCH to the corresponding UE include a bitmap of the NRBG bit. Its conditions will be described later. At this time, NRBG is the number of RBGs, as shown in Table 19 below, determined according to the BWP size allocated by the BWP indicator and the high-level parameter rbg-Size, and data is sent in the RBG indicated by the bitmap as 1.

[0332] [Table 19]

[0333]

[0334] When the UE is configured to use only resource type 1 through high-level signaling, as shown in reference numeral 13-05, some DCIs for allocating PDSCH to the corresponding UE include The BS may configure a starting virtual RB (VRB) 13-20 and the length 13-25 of the frequency axis resources continuously allocated therefrom.

[0335] When the UE is configured to use both resource type 0 and resource type 1 through high-level signaling, as shown in the figure mark 13-10, some DCIs for allocating PDSCH to the corresponding UE include frequency-axis resource allocation information of a bit of a larger value 13-35 among payloads 13-20 and 13-25 for configuring resource type 0 and a payload 13-15 for configuring resource type 1. The conditions will be described again later. At this time, one bit can be added to the first part of the frequency-axis resource allocation information within the DCI (e.g., the most significant bit (MSB)), and when the corresponding bit is "0", it can indicate the use of resource type 0, and when the corresponding bit is "1", it can indicate the use of resource type 1.

[0336] [PDSCH / PUSCH: related to time resource allocation]

[0337] Hereinafter, a method of allocating time domain resources for a data channel in a wireless communication system (e.g., a 5G or NR system) is described.

[0338] The BS may configure a table of time domain resource allocation information for a downlink data channel (e.g., PDSCH) and an uplink data channel (e.g., PUSCH) in the UE through high-layer signaling (e.g., RRC signaling). A table including a maximum of maxNrofDL-Allocations=16 entries may be configured for PDSCH, and a table including a maximum of maxNrofUL-Allocations=16 entries may be configured for PUSCH. The time domain resource allocation information may include PDCCH to PDSCH slot timing (corresponding to the time interval in time slots between the time point when the PDCCH is received and the time point when the PDSCH scheduled by the received PDCCH is transmitted, and indicated by K0 in Table 20) or PDCCH to PUSCH slot timing (corresponding to the time interval in time slots between the time point when the PDCCH is received and the time point when the PUSCH scheduled by the received PDCCH is transmitted, and indicated by K2 in Table 21), the position and length of the starting symbol in which the PDSCH or PUSCH is scheduled within the slot, and the mapping type of the PDSCH or PUSCH. For example, the information shown in Table 20 or Table 21 below may be sent from the BS to the UE.

[0339] [Table 20]

[0340]

[0341] [Table 21]

[0342]

[0343]

[0344] The BS may inform the UE of one of the entries in the table of time domain resource allocation information through L1 signaling (eg, DCI indicating the time domain resource allocation field). The UE may acquire the time domain resource allocation information of the PDSCH or PUSCH based on the DCI received from the BS.

[0345] Fig.14 An example of allocation of time axis resources of a PDSCH in a wireless communication system according to an embodiment of the present disclosure is shown.

[0346] refer to Fig.14 BS can use the SCS (μ PDSCH , μ PDCCH ), scheduling offset (K0) value, and the OFDM symbol start position 14-00 and length 14-05 within a time slot dynamically indicated by DCI to indicate the time axis position of the PDSCH resource.

[0347] Fig.15 An example of allocation of time axis resources according to subcarrier spacings of data channels and control channels in a wireless communication system according to an embodiment of the present disclosure is shown.

[0348] refer to Fig.15 , when the subcarrier spacing of the data channel and the control channel is the same as each other (μ PDSCH =μ PDCCH ), as shown in the reference numeral 15-00, the time slot numbers for data and control are the same, so the BS and the UE can generate a scheduling offset according to the predetermined time slot offset K0. On the other hand, when the subcarrier spacing of the data channel and the control channel is different from each other (μ PDSCH ≠μ PDCCH ), as shown in the figure mark 15-05, the time slot numbers used for data and control are different from each other, so the BS and the UE can generate a scheduling offset according to the predetermined time slot offset K0 based on the subcarrier spacing of the PDCCH.

[0349] [PDSCH: TCI state activated MAC-CE]

[0350] Next, a beam configuration method for PDSCH is described. Fig.16The process of beam configuration and activation of PDSCH is shown. The TCI state list of PDSCH can be indicated by a high-level list such as RRC (as shown in reference numeral 16-00). The list of TCI states can be indicated by tci-StatesToAddModList (tci-state add mode list) and / or tci-StatesToReleaseList (tci-state release list) in, for example, the BWP-specific PDSCH-Config (PDSCH-Configuration) IE. Next, a portion of the TCI state list can be activated by MAC CE (as shown in reference numerals 16-20). The maximum number of activated TCI states can be determined based on the capabilities reported by the terminal. Reference numeral 16-50 indicates an example of a MAC-CE structure for PDSCH TCI state activation / deactivation.

[0351] The meaning of each field in MAC CE and the available values ​​in each field can be shown in Table 22.

[0352] [Table 22]

[0353]

[0354] [PUSCH: related to transmission scheme]

[0355] Next, a scheme for scheduling PUSCH transmission will be described. PUSCH transmission can be dynamically scheduled by UL grant in DCI, or can be operated by configured grant type 1 or type 2. Dynamic scheduling indication of PUSCH transmission can be performed by DCI format 0_0 or 0_1.

[0356] In the absence of reception of an UL grant in DCI, a configured grant type 1 PUSCH transmission may be semi-statically configured by receiving a configuredGrantConfig including an rrc-ConfiguredUplinkGrant as shown in Table 23 through higher signaling. After receiving a configuredGrantConfig not including an rrc-ConfiguredUplinkGrant as shown in Table 23 through higher signaling, a configured grant type 2 PUSCH transmission may be semi-persistently scheduled by an UL grant in DCI. In the case of operating PUSCH transmission by a configured grant, the parameters applied to PUSCH transmission may be applied by configuredGrantConfig, which is higher signaling in Table 23, except for dataScramblingIdentityPUSCH, txConfig, codebookSubset, maxRank, and scaling of UCI-OnPUSCH provided by pusch-Config as shown in Table 24 of higher signaling. When transformPrecoder in configuredGrantConfig as higher signaling in Table 23 is provided to the terminal, the terminal applies tp-pi2BPSK in pusch-Config of Table 24 to PUSCH transmission operated by the configured grant.

[0357] [Table 23]

[0358]

[0359] Next, the PUSCH transmission method is described. The DMRS antenna port used for PUSCH transmission is the same as the antenna port used for SRS transmission. PUSCH transmission can follow each of the codebook-based transmission method and the non-codebook-based transmission method according to whether the value of txConfig in pusch-Config of Table 24 as higher signaling is "codebook" or "non-codebook".

[0360] As described above, PUSCH transmission can be dynamically scheduled through DCI format 0_0 or 0_1, and can be semi-statically configured through a configured grant. If the scheduling of PUSCH transmission is indicated to the terminal through DCI format 0_0, the terminal can perform beam configuration for PUSCH transmission by using pucch-spatialRelationInfoID (pucch-spatial related information ID), which corresponds to the terminal-specific PUCCH resource corresponding to the lowest ID in the uplink BWP activated in the serving cell. PUSCH transmission is based on a single antenna port. Within a BWP where a PUCCH resource including pucch-spatialRelationInfo (pucch-spatial related information) is not configured, the terminal does not expect scheduling of PUCCH transmission through DCI format 0_0. If the txConfig in pusch-Config of Table 24 is not configured for the terminal, the terminal may not expect to be scheduled through DCI format 0_1.

[0361] [Table 24]

[0362]

[0363] Next, codebook-based PUSCH transmission is described.

[0364] Codebook-based PUSCH transmission can be dynamically scheduled by DCI format 0_0 or 0_1, and can be operated semi-statically by the configured grant. If the codebook-based PUSCH is dynamically scheduled by DCI format 0_1 ​​or semi-statically operated by the configured grant, the terminal determines the precoder for PUSCH transmission based on the SRS resource indicator (SRI), the transmission precoding matrix indicator (TPMI) and the transmission rank (the number of PUSCH transmission layers).

[0365] SRI can be given by an SRS resource indicator as a field in DCI, or can be configured by srs-ResourceIndicator (srs-resource indicator) as higher signaling. In codebook-based PUSCH transmission, at least one SRS resource can be configured for the terminal, and up to two SRS resources can be configured. In the case where SRI is provided to the terminal through DCI, the SRS resource indicated by SRI indicates the SRS resource corresponding to SRI among the SRS resources sent before the PDCCH including SRI. In addition, TPMI and transmission rank can be given by precoding information and the number of layers as a field in DCI, or can be configured by precodingAndNumberOfLayers (precoding and number of layers) as higher signaling. TPMI is used to indicate the precoder applied to PUSCH transmission. If one SRS resource is configured for the terminal, TPMI is used to indicate the precoder to be applied in one configured SRS resource. If multiple SRS resources are configured for the terminal, TPMI is used to indicate the precoder to be applied in the SRS resource indicated by SRI.

[0366] The precoder to be used for PUSCH transmission is selected in an uplink codebook having the number of antenna ports corresponding to the value of nrofSRS-Ports (number of SRS ports) in SRS-Config as higher signaling. In codebook-based PUSCH transmission, the terminal determines the codebook subset based on TPMI and codebookSubset in pusch-Config as higher signaling. Based on the UE capabilities reported by the UE to the base station, the codebookSubset in pusch-Config as higher signaling can be configured as one of "fullyAndPartialAndNonCoherent", "partialAndNonCoherent" or "nonCoherent". If the terminal reports "partialAndNonCoherent" as the UE capability, the terminal does not expect the value of codebookSubset as higher signaling to be configured as "fullyAndPartialAndNonCoherent". In addition, if the terminal reports "nonCoherent" as the UE capability, the terminal does not expect the value of codebookSubset as the higher signaling to be configured as "fullyAndPartialAndNonCoherent" or "partialAndNonCoherent". In the case where nrofSRS-Ports in SRS-ResourceSet (SRS-resource set) as the higher signaling indicates two SRS antenna ports, the terminal does not expect the value of codebookSubset as the higher signaling to be configured as "partialAndNonCoherent".

[0367] An SRS resource set configured by a "codebook" as a usage value in an SRS-ResourceSet of higher signaling may be configured for the terminal, and an SRS resource in the SRS resource set may be indicated by SRI. If several resources are configured in an SRS resource set configured by a "codebook" as a usage value in an SRS-ResourceSet of higher signaling, the terminal expects that the value of nrofSRS-Ports in an SRS-Resource of higher signaling is configured to be the same for all SRS resources.

[0368] The terminal may send one or more SRS resources included in an SRS resource set configured by a "codebook" as a usage value according to higher signaling to the base station, and the base station may select one from the SRS resources sent by the terminal and instruct the terminal to perform PUSCH transmission by using the transmission beam information about the selected SRS resource. In codebook-based PUSCH transmission, SRI is used as information for selecting an index of an SRS resource and is included in the DCI. In addition, the base station may include information indicating the TPMI and rank to be used by the terminal for PUSCH transmission in the DCI. The terminal may use the SRS resource indicated by the SRI to apply the precoder indicated by the TPMI and the rank indicated based on the transmission beam of the SRS resource in order to perform PUSCH transmission.

[0369] Next, non-codebook based PUSCH transmission is described.

[0370] Non-codebook based PUSCH transmission can be dynamically scheduled through DCI format 0_0 or 0_1, and can be operated semi-statically through the configured grant. In the case where at least one SRS resource is configured in the SRS resource set configured by "non-codebook" as the usage value in the SRS-ResourceSet of higher signaling, non-codebook based PUSCH transmission can be scheduled for the terminal through DCI format 0_1.

[0371] For an SRS resource set that is a "non-codebook" configured using a value in a higher signaling SRS-ResourceSet, a connected non-zero power (NZP) CSI-RS resource can be configured for the terminal. The terminal can perform calculation of the precoder for SRS transmission by measuring the NZP CSI-RS resource connected to the SRS resource set. In the case where the difference between the first symbol of the terminal's aperiodic SRS transmission and the last received symbol of the aperiodic NZP CSI_RS resource connected to the SRS resource set is less than 42 symbols, the terminal does not expect the information about the precoder used for SRS transmission to be updated.

[0372] If the value of resourceType in SRS-ResourceSet as higher signaling is configured as "non-periodic", the connected NZP CSI-RS is indicated by the SRS request as a field in DCI format 0_1 ​​or 1_1. In the case where the connected NZP CSI-RS resource is a non-periodic NZP CSI-RS resource, this means that for the case where the value of the SRS request as a field in DCI format 0_1 ​​or 1_1 is not "00", there is a connected NZP CSI-RS. The corresponding DCI is required not to indicate cross-carrier or cross-BWP scheduling. In addition, if the value of the SRS request indicates the presence of NZP CSI-RS, the NZP CSI-RS may be located in the time slot in which the PDCCH including the SRS request field is transmitted. The TCI state configured for the scheduled subcarrier may not be configured as QCL-Type D.

[0373] If a periodic or semi-persistent SRS resource set is configured, the connected NZP CSI-RS can be indicated by the associatedCSI-RS in the SRS-ResourceSet as the higher signaling. For non-codebook based transmission, the terminal does not expect the spatialRelationInfo as the higher signaling of the SRS resource to be configured together with the associatedCSI-RS in the SRS-ResourceSet as the higher signaling.

[0374] In the case where multiple SRS resources are configured for the terminal, the terminal can determine the precoder and transmission rank to be applied to the PUSCH transmission based on the SRI indicated by the base station. The SRI can be indicated by an SRS resource indicator, which is a field in the DCI, or can be configured by an srs-ResourceIndicator as a higher signaling. Similar to the above-mentioned codebook-based PUSCH transmission, in the case where the SRI is provided to the terminal through the DCI, the SRS resource indicated by the SRI indicates the SRS resource corresponding to the SRI among the SRS resources sent before the PDCCH including the SRI. The terminal can use one or more SRS resources for SRS transmission, and determine the maximum number of SRS resources and the maximum number of SRS resources that can be sent simultaneously in the same symbol in an SRS resource set based on the UE capabilities reported by the terminal to the base station. The SRS resources sent simultaneously by the terminal occupy the same RB. The terminal configures an SRS port for each SRS resource. The number of SRS resource sets configured by "non-codebook" as a usage value in SRS-ResourceSet of higher signaling may be configured to only one, and the number of SRS resources used for non-codebook-based PUSCH transmission may be configured to up to four.

[0375] The base station can send an NZP CSI-RS connected to the SRS resource set to the terminal, and the terminal calculates the precoder to be used to send one or more SRS resources in the SRS resource set based on the results of the measurement performed when receiving the NZP CSI-RS. When sending one or more SRS resources in the SRS resource set configured by the "non-codebook" used to the base station, the terminal applies the calculated precoder, and the base station selects one or more SRS resources from the received one or more SRS resources. In the non-codebook based PUSCH transmission, the SRI indicates an index that can represent a combination of one or more 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 transmission layers of the PUSCH, and the terminal applies the precoder applied to the SRS resource transmission to each layer in order to send the PUSCH.

[0376] [Related to terminal capability report]

[0377] In a wireless communication system (eg, LTE system, 5G system or NR system), when the UE is connected to a serving BS, the UE may perform a process for reporting the capabilities supported by the UE to the corresponding BS. In the following description, this is referred to as UE capability reporting.

[0378] The BS may send a UE capability query message that requests a capability report from a UE in a connected state. The message may include a UE capability request for each radio access technology (RAT) type of the BS. The request for each RAT type may include supported frequency band combination information. In the case of a UE capability query message, multiple UE capabilities for each RAT type may be requested through one RRC message container sent by the BS, or the BS may insert a UE capability query message including a UE capability request for each RAT type multiple times and send it to the UE. That is, the UE capability query is repeated multiple times within one message, and the UE may configure a UE capability information message corresponding thereto and report it multiple times. In the next generation mobile communication system, UE capability requests may be made for NR, LTE, E-UTRA-NR dual connectivity (EN-DC) and multi-RAT dual connectivity (MR-DC). The UE capability query message is usually initially sent after the UE is connected to the BS, but may be requested at any time when the BS needs it.

[0379] The UE that receives the request for UE capability report from the BS in the above steps can configure the UE capability according to the RAT type and frequency band information requested by the BS. A method for configuring UE capability of a UE in a wireless communication system (e.g., a 5G or NR system) is described below.

[0380] 1. When the UE receives a list of LTE and / or NR bands from the BS through a UE capability request, the UE configures a band combination (BC) for EN-DC and NR standalone (SA). That is, the UE configures a candidate list of BCs for DC and NR SA based on the bands requested in FreqBandList. The bands have priorities sequentially as described in FreqBandList.

[0381] 2. When the BS sets the "eutra-nr-only" flag or the "eutra" flag and makes a request for UE capability reporting, the UE completely removes the NR SA BC from the candidate list of configured BCs. Such an operation can only occur when the LTE BS (eNB) makes a request for "eutra" capability.

[0382] 3. Thereafter, the UE removes the fallback BC from the candidate list of BCs configured in the above stage. The fallback BC is a BC that can be obtained by removing the frequency band corresponding to at least one SCell from the predetermined BC, and the BC before removing the frequency band corresponding to at least one SCell can cover the fallback BC, and thus the fallback BC can be omitted. This stage is applicable to MR-DC, that is, the LTE band. The BC left after this stage is the final "candidate BC list".

[0383] 4. The UE selects a BC suitable for the requested RAT type in the final "candidate BC list" and selects the BC to be reported. At this stage, the UE configures the supportedBandCombinationList according to the determined order. That is, the UE configures the BC to be reported and the UE capabilities according to the preset rat-Type order (nr->eutra-nr->eutra). In addition, the UE configures the featureSetCombination for the configured supportedBandCombinationList, and configures a list of "candidate feature set combinations" from the candidate BC list from which it is received in the list for fallback BC (including capabilities of the same or lower stage). The "candidate feature set combination" can include all feature set combinations for NR and EUTRA-NR BCs, and can be obtained from the feature set combinations of UE-NR-capability and UE-MRDC-capability containers.

[0384] 5. When the requested rat type is eutra-nr and influences, the featureSetCombination is included in both containers of all UE-MRDC-capabilities and UE-NR-capabilities. However, the NR feature set only includes UE-NR-capabilities.

[0385] After configuring the UE capabilities, the UE may transmit a UE capability information message including the UE capabilities to the BS. The BS may perform scheduling and transmission / reception management of the corresponding UE based on the UE capabilities received from the UE.

[0386] [CA / DC related]

[0387] Fig.17 The wireless protocol structure of the BS and UE in a single cell, CA and DC according to an embodiment of the present disclosure is shown.

[0388] refer to Fig.17 , the radio protocol of a wireless communication system (e.g., a 5G or NR system) includes an NR service data adaptation protocol (SDAP) 1725 or 1770, an NR packet data convergence protocol (PDCP) 1730 or 1765, an NR radio link control (RLC) 1735 or 1760, and an NR medium access control (MAC) 1740 or 1755 in each of the UE and the NR gNB.

[0389] The main functions of NR SDAP 1725 or 1770 may include some of the following functions:

[0390] -User data transmission function (transmission of user plane data);

[0391] - Functionality for mapping QoS flows and data bearers for uplink and downlink (mapping between QoS flows and DRBs for both DL and UL);

[0392] - Functionality to mark QoS Flow ID for uplink and downlink (mark QoS Flow ID in both DL and UL packets); and

[0393] - Functionality to map Reflective QoS flows to data bearers for uplink SDAP PDUs (Reflective QoS flows to DRB mapping for UL SDAP PDUs).

[0394] Regarding the SDAP layer device, the UE may receive configuration regarding whether to use the header of the SDAP layer device or the function of the SDAP layer device for each PDCP layer device, each bearer, or each logical channel through an RRC message. If the SDAP header is configured, the 1-bit indicator of the non-access stratum (NAS) reflected QoS and the 1-bit indicator of the AS reflected QoS of the SDAP header may indicate that the UE updates or reconfigures information regarding the mapping of QoS flows and data bearers in the uplink and downlink. The SDAP header may include QoS flow ID information indicating QoS. The QoS information may be used as data-processing-priority or scheduling information to support seamless service.

[0395] The main functions of NR PDCP 1730 or 1765 may include some of the following functions:

[0396] - Header compression and decompression functionality (Header Compression and Decompression: Robust Header Compression (ROHC) only);

[0397] -User data transmission function (transmission of user data);

[0398] - Sequence delivery function (in-sequence delivery of upper layer PDUs);

[0399] - Out-of-sequence delivery function (out-of-order delivery of upper layer PDUs);

[0400] - Reordering function (for reordering of received PDCP PDUs);

[0401] - Duplicate detection function (duplicate detection of lower layer SDU);

[0402] -Retransmission function (retransmission of PDCP SDU);

[0403] - encryption and decryption functions (encryption and decryption); and

[0404] - Timer-based SDU removal functionality (timer-based SDU discard in uplink).

[0405] The reordering function of the NR PDCP layer device is a function of sequentially reordering the PDCP PDUs received from the lower layer based on the PDCP sequence number (SN), and may include a function of sequentially transmitting the reordered data to the higher layer. The reordering function of the NR PDCP layer device may include a function of directly sending data regardless of the sequence, a function of recording the PDCP PDU lost due to reordering, a function of reporting the status of the lost PDCP PDU to the transmitting side, and a function of requesting retransmission of the lost PDCP PDU.

[0406] The main functions of NR RLC 1735 or 1760 may include some of the following functions:

[0407] -Data transmission function (transmission of upper layer PDU);

[0408] - Sequence delivery function (in-sequence delivery of upper layer PDUs);

[0409] - Out-of-sequence delivery function (out-of-order delivery of upper layer PDUs);

[0410] - Automatic repeat request (ARQ) function (error correction through ARQ);

[0411] - Concatenation, segmentation and reassembly function (concatenation, segmentation and reassembly of RLC SDU);

[0412] -Resegmentation function (re-segmentation of RLC data PDU);

[0413] - Reordering function (reordering of RLC data PDU);

[0414] - Duplicate detection function (duplicate detection);

[0415] - Error detection function (protocol error detection);

[0416] - RLC SDU deletion function (RLC SDU discard); and

[0417] - RLC re-establishment function (RLC Re-establishment).

[0418] The sequential delivery function (in-sequence delivery) of the NR RLC layer device is a function of sequentially sending the RLC SDU received from the lower layer to the higher layer. When one original RLC SDU is divided into multiple RLC SDUs and then received, the sequential delivery function (in-sequence delivery) of the NR RLC layer device may include a function of reassembling and sending the RLC SDU, a function of reordering the received RLC PDU based on the RLC SN or PDCP SN, a function of recording the RLC PDU lost due to reordering, a function of reporting the status of the lost RLC PDU to the transmitting side, and a function of requesting retransmission of the lost RLC PDU. When there is a lost RLC SDU, the sequential delivery function (in-sequence delivery) of the NR RLC layer device may include a function of sequentially transmitting only the RLC SDU before the lost RLC SDU to the higher layer, or if a predetermined timer expires (even if there is a lost RLC SDU), a function of sequentially transmitting all RLC SDUs received before the timer starts to the higher layer. Alternatively, the sequential delivery function (in-sequence delivery) of the NR RLC layer device may include a function of sequentially transmitting all RLC SDUs received so far to the higher layer if a predetermined timer expires (even if there is a lost RLC SDU). In addition, the NR RLC device can process the RLC PDUs sequentially in the order in which they are received (according to the arrival order, regardless of the series number or sequence number), and can transmit the RLC PDUs to the PDCP device regardless of their sequence (out-of-sequence delivery). In the case of segmentation, the NR RLC device can receive segments stored in the buffer or to be received in the future, reconfigure the segments into one RLC PDU, process the RLC PDU, and then send it to the PDCP device. The NR RLC layer device may not include a cascading function, and the function may be performed by the NR MAC layer, or may be replaced by a multiplexing function of the NR MAC layer.

[0419] The non-sequential function (out-of-order delivery) of the NR RLC layer device is a function of directly transmitting the RLC SDU received from the lower layer to the higher layer regardless of the sequence of the RLC SDU, and may include, when an original RLC SDU is divided into multiple RLC SDUs and then received, the function of reassembling and sending the RLC PDU, and the function of storing the RLC SN or PDCP SN of the received RLC PDU, reordering the RLC PDU and recording the lost RLC PDU.

[0420] The NR MAC 1740 or 1755 may be connected to a plurality of NR RLC layer devices configured in one UE, and the main functions of the NR MAC may include some of the following functions:

[0421] - Mapping function (mapping between logical channels and transport channels);

[0422] -Multiplexing and demultiplexing functions (multiplexing / demultiplexing of MAC SDU);

[0423] -Scheduling information reporting function (Scheduling information reporting);

[0424] -HARQ functionality (error correction via HARQ);

[0425] -Logical channel priority control function (priority handling between logical channels of a UE);

[0426] -UE priority control function (with the help of priority handling between dynamically scheduled UEs);

[0427] -MBMS service identification function (MBMS service identification);

[0428] - a transmission format selection function (Transmission Format Selection); and

[0429] - Filling function (fill).

[0430] The NR PHY layer 1745 or 1750 performs an operation of channel coding and modulating high-layer data to generate OFDM symbols and transmitting the OFDM symbols through a radio channel, or performs an operation of demodulating and channel decoding OFDM symbols received through a radio channel and transmitting the demodulated and channel-decoded OFDM symbols to a high-layer.

[0431] The detailed structure of the wireless protocol may be changed differently depending on the carrier (or cell) operation scheme. For example, when the BS sends data to the UE based on a single carrier (or cell), the BS and the UE use a protocol structure having a single structure for each layer, as shown in reference numeral 1700. On the other hand, when the BS sends data to the UE using multiple carriers in a single TRP based on CA, the BS and the UE use a protocol structure in which the layers up to the RLC have a single structure, but the PHY layer is multiplexed through the MAC layer, as shown in reference numeral 1710. In another example, when the BS sends data to the UE using multiple carriers in multiple TRPs based on DC, the BS and the UE use a protocol structure in which the layers up to the RLC have a single structure, but the PHY layer is multiplexed through the MAC layer, as shown in reference numeral 1720.

[0432] Referring to the above description related to PDCCH and beam configuration, in scenarios requiring high reliability, such as in URLLC, it is difficult to achieve the required reliability because PDCCH repeated transmission is not currently supported in Rel-15 and Rel-16 NR. The present disclosure improves the PDCCH reception reliability of the terminal by providing a PDCCH repeated transmission method via multiple transmission points (TRP).

[0433] Hereinafter, the embodiments of the present disclosure are applicable to FDD and TDD systems. Higher signaling (or high-layer signaling) may be a signal transmission method of sending a signal from a BS to a terminal by using a downlink data channel of a physical layer or sending a signal from a terminal to a BS by using an uplink data channel of a physical layer, and may be referred to as RRC signaling, PDCP signaling, or a MAC control element (CE).

[0434] When determining whether to apply collaborative communication, the UE may use various methods by which the PDCCH to which the collaborative communication is applied is assigned has a specific format, the PDCCH to which the collaborative communication is applied includes a specific indicator notifying whether the collaborative communication is applied, the PDCCH to which the collaborative communication is applied is assigned is scrambled by a specific RNTI, or it is assumed that the collaborative communication is applied to a specific part indicated by a higher layer. Hereinafter, for convenience of description, the reception of the PDSCH to which the collaborative communication is applied by the UE based on conditions similar to the above conditions is referred to as an "NC-JT" case (non-coherent joint transmission (NC-JT) case).

[0435] Determining the priority between A and B can be achieved in various ways, such as selecting the one with a higher priority to execute the operation corresponding to it according to a predetermined priority rule, or omitting or discarding the operation with a lower priority.

[0436] Hereinafter, in the present disclosure, the above examples will be explained through a plurality of embodiments. However, the embodiments are not independent, and one or more embodiments may be applied simultaneously or in combination.

[0437] [NC-JT related]

[0438] According to an embodiment of the present disclosure, in order to receive PDSCH from multiple TRPs, the UE may use NC-JT.

[0439] Unlike traditional systems, wireless communication systems (e.g., 5G or NR systems) can support all services with very short transmission delays, services requiring high connection density, and services requiring high transmission rates. In a wireless communication network including multiple cells, TRPs, or beams, cooperative communication (coordinated transmission) between various 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.

[0440] Joint transmission (JT) is a representative transmission technology for cooperative communication, and can increase the strength or throughput of the signal received by a UE by sending a signal to a UE via different cells, TRPs and / or beams. At this time, the channel between each cell, TRP and / or beam and the UE may have different characteristics. Specifically, NC-JT that supports non-coherent precoding between various cells, TRPs and / or beams may require separate precoding, MCS, resource allocation and TCI indication according to the channel characteristics of each link between each cell, TRP and / or beam and the UE.

[0441] NC-JT can be applied to at least one of a downlink data channel (e.g., PDSCH), a downlink control channel (e.g., PDCCH), an uplink data channel (e.g., PUSCH), and an uplink control channel (e.g., PUCCH). In PDSCH transmission, transmission information such as precoding, MCS, resource allocation, and TCI can be indicated by DL DCI, and should be indicated independently for each cell, TRP, and / or beam of NC-JT. This is an important factor in increasing the payload required for DL ​​DCI transmission, which may have an adverse effect on the reception performance of the PDCCH used to send the DCI. Therefore, in order to support JT of PDSCH, the tradeoff between the amount of DCI information and the reception performance of the control information needs to be carefully designed.

[0442] Fig.18 An example of configuration of antenna ports and resource allocation for transmitting a PDSCH using cooperative communication in a wireless communication system according to an embodiment is shown.

[0443] refer to Fig.18 , an example of PDSCH transmission is described for each scheme of JT, and an example of allocating radio resources for each TRP is described.

[0444] refer to Fig.18 , an example 1800 of coherent JT (C-JT) supporting inter-preferential coding between individual cells, TRPs and / or beams is shown.

[0445] In the case of C-JT, TRP A 1805 and TRP B 1810 transmit a single data (e.g., PDSCH) to UE 1818, and multiple TRPs may perform joint precoding. This may mean that TRP A 1805 and TRP B 1810 transmit DMRS through the same DMRS port in order to transmit the same PDSCH. For example, TRP A 1805 and TRP B 1810 may transmit DMRS to the UE through DMRS port A and DMRS port B, respectively. In this case, the UE may receive one DCI information for receiving one PDSCH demodulated based on the DMRS transmitted through DMRS port A and DMRS port B.

[0446] Fig.18 An example 1820 is shown in which NC-JT supports non-coherent interfering coding between various cells, TRPs and / or beams for PDSCH transmission.

[0447] In the case of NC-JT, PDSCH is sent to UE 1835 for each cell, TRP and / or beam, and separate precoding can be applied to each PDSCH. Each cell, TRP and / or beam can send different PDSCHs or different PDSCH layers to the UE, thereby improving throughput compared to single cell, TRP and / or beam transmission. In addition, each cell, TRP and / or beam can repeatedly send 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 collectively referred to as TRPs.

[0448] At this time, various wireless resource allocations can be considered, such as the case 1840 where the frequency and time resources used by multiple TRPs for PDSCH transmission are the same, the case 1845 where the frequency and time resources used by multiple TRPs do not overlap at all, and the case 1850 where some frequency and time resources used by multiple TRPs overlap with each other.

[0449] To support NC-JT, various forms, structures, and relationships of DCI may be considered to simultaneously allocate multiple PDSCHs to a UE.

[0450] Fig.19 An example of configuration of DCI for cooperative communication in a wireless communication system according to an embodiment of the present disclosure is shown.

[0451] For example, Fig.19 The configuration of DCI of NC-JT in a wireless communication system is shown, where each TRP sends different PDSCHs or different PDSCH layers to the UE.

[0452] refer to Fig.19 , Case #1 1900 is an example in which, in the case 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) for a single PDSCH transmission, the control information of the PDSCHs transmitted from the (N-1) additional TRPs is transmitted independently of the control information of the PDSCHs transmitted by the serving TRP. That is, the UE can obtain the control information of the PDSCHs transmitted from different TRPs (TRP#0 to TRP#(N-1)) through independent DCIs (DCI#0 to DCI#(N-1)). The formats between independent DCIs may be the same as or different from each other, and the payloads between DCIs may also be the same as or different from each other. In Case #1, the freedom of PDSCH control or allocation can be fully guaranteed, but when each DCI is transmitted through different TRPs, a difference between DCI coverage may be generated, and reception performance may deteriorate.

[0453] Case #2 1905 is an example where, in the case where (N-1) different PDSCHs are transmitted from (N-1) additional TRPs (TRP#1 to TRP#(N-1)) in addition to the serving TRP (TRP#0) for a single PDSCH transmission, control information of the PDSCH for the (N-1) additional TRPs is transmitted, and each DCI depends on the control information of the PDSCH transmitted from the serving TRP.

[0454] DCI#0, which is control information of the PDSCH 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, but shortened DCI (hereinafter referred to as sDCI) (sDCI#0 to sDCI#(N-2)), which is control information of the PDSCH sent from the collaborative TRP (TRP#1 to TRP#(N-1)), may include only some information elements of DCI format 1_0, DCI format 1_1, and DCI format 1_2. Therefore, compared with the normal DCI (nDCI) used to send control information related to the PDSCH sent from the serving TRP, the sDCI used to send control information of the PDSCH sent from the collaborative TRP has a smaller payload and can therefore include reserved bits compared with the nDCI.

[0455] In case #2 1905, the degree of freedom of each PDSCH control or allocation may be limited depending on the content of the information elements included in the sDCI, but the reception capability of sDCI is better than nDCI, and thus the probability of generating a difference between DCI coverage may become lower.

[0456] Case #3 1910 is an example where, in the case 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) for a single PDSCH transmission, one control information of the PDSCHs of the (N-1) additional TRPs is transmitted, and the DCI depends on the control information of the PDSCH transmitted from the serving TRP.

[0457] In the case of DCI#0, which is the control information of the 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 may be included, and in the case of control information of the PDSCH sent from the collaborative TRP (TRP#1 to TRP#(N-1)), only some information elements of DCI format 1_0, DCI format 1_1, and DCI format 1_2 may be collected in one "auxiliary" DCI (sDCI) and sent. The sDCI may include at least one HARQ-related information, such as frequency domain resource allocation and time domain resource allocation of the collaborative TRP and MCS. In addition, information not included in the sDCI (such as a BWP indicator and a carrier indicator) may follow the DCI of the serving TRP (DCI#0, normal DCI, or nDCI).

[0458] In case #3 1910, the freedom of PDSCH control or allocation can be limited according to the content of the information elements included in the sDCI, but the reception performance of the sDCI can be controlled, and compared with case #1 1900 or case #2 1905, case #3 1910 can have a smaller complexity of DCI blind decoding of the UE.

[0459] Case #4 1915 is an example in which, in the case where different (N-1) PDSCHs are transmitted from (N-1) additional TRPs (TRP#1 to TRP#(N-1)) other than the serving TRP (TRP#0) for a single PDSCH transmission, control information of the PDSCH transmitted from the (N-1) additional TRPs is transmitted in the same DCI (long DCI) as the control information of the PDSCH transmitted from the serving TRP. That is, the UE can acquire control information of the PDSCH transmitted from different TRPs (TRP#0 to TRP#(N-1)) through a single DCI. In case #4 1915, the complexity of the UE's DCI blind decoding may not increase, but the degree of freedom of PDSCH control or allocation may be low because the number of collaborative TRPs is limited according to the long DCI payload limitation.

[0460] sDCI may refer to various supplementary DCIs including PDSCH control information sent in a collaborative TRP, such as shortened DCI, auxiliary DCI, or normal DCI (DCI formats 1_0 and 1_1), and unless specific limitations are mentioned, the corresponding description may be similarly applied to various supplementary DCIs.

[0461] Case #1 1900, case #2 1905, and case #3 1910 of using one or more DCIs (or PDCCHs) to support NC-JT can be classified as NC-JT based on multiple PDCCHs, while case #4 1915 of using a single DCI (or PDCCH) 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 scheduling DCI of the service TRP (TRP#0) is separated from the CORESET of the scheduling DCI of the collaborative TRP (TRP#1 to TRP#(N-1)). Methods of distinguishing CORESETs may include a distinguishing method by a high-layer indicator for each CORESET and a distinguishing method by a beam configuration for each CORESET. In addition, 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. At this time, the association between the layer and the TRP of the corresponding layer sent can be indicated by the TCI indication of the layer.

[0462] When applicable, "collaborative TRP" may be replaced by various terms such as "collaborative panel" or "collaborative beam".

[0463] The “case where NC-JT is applied” can be interpreted differently depending on the case as “the case where the UE simultaneously receives one or more PDSCHs in one BWP”, “the case where the UE simultaneously receives PDSCHs in one BWP based on two or more TCI indications” and “the case where the PDSCH received by the UE is associated with one or more DMRS port groups”. However, for the convenience of description, one expression is used.

[0464] In the present disclosure, the wireless protocol structure of NC-JT can be used differently according to the TRP development scenario. For example, when there is no backhaul delay or a small backhaul delay between cooperative TRPs, a method using a structure based on MAC layer multiplexing (a CA-like method) can be used, similar to Fig.17On the other hand, when the backhaul delay between the cooperative TRPs is too large to be ignored (for example, when 2 ms or more is required to exchange information such as CSI, scheduling, and HARQ-ACK between the cooperative TRPs), a method of ensuring a characteristic robust to delay (a DC-like method) may be used by an independent structure of each TRP from the RLC layer, similar to Fig.17 1720 of the figure.

[0465] A UE supporting C-JT / NC-JT can receive C-JT / NC-JT related parameters or setting values ​​from a high-level configuration and set the UE's RRC parameters based thereon. For high-level configuration, the UE can use UE capability parameters, such as tci-StatePDSCH. UE capability parameters, such as tci-StatePDSCH, can define TCI states for PDSCH transmission, and 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, and among the configured numbers, a maximum of 8 states that can be indicated by 3 bits of the TCI field of the DCI can be configured through a MAC CE message. The maximum value of 128 represents the value indicated by the maxNumberConfiguredTCIstatesPerCC in the parameter tci-StatePDSCH included in the UE's capability signaling. As described above, a series of configuration processes from high-level configuration to MAC CE configuration can be applied to a beamforming indication or beamforming change command for at least one PDSCH in a TRP.

[0466] [Multiple TRPs based on multiple DCIs]

[0467] As an embodiment of the present disclosure, a multi-TRP transmission method based on multiple DCIs is described. Through the multi-TRP transmission method based on multiple DCIs, a downlink control channel for NC-JT transmission can be configured based on multiple PDCCHs.

[0468] In NC-JT based on multiple PDCCHs, when sending DCI for scheduling PDSCH of each TRP, there may be a CORESET or search space separated for each TRP. The CORESET or search space of each TRP can be configured according to at least one of the following configuration cases.

[0469] *Configuration of high-level index for each CORESET: The CORESET configuration information configured by the high-level layer may include an index value, and the TRP used to send PDCCH in the corresponding CORESET may be identified by the index value configured for each CORESET. That is, in a set of CORESERs with the same high-level index value, the same TRP may send PDCCH or the PDCCH for scheduling PDSCH of the same TRP may be sent. The index of each CORESET may be named CORESETPoolIndex, and the PDCCH may be considered to be sent from the same TRP in the CORESET configured with the same CORESETPoolIndex value. In a CORESET that is not configured with the same CORESETPoolIndex value, a default value of CORESETPoolIndex may be configured, which may be 0.

[0470] In the present disclosure, if the number of CORESETPoolIndex types of multiple CORESETs included in the PDCCH-configuration as high-layer signaling exceeds 1, that is, if the CORESETs have different CORESETPoolIndex, the terminal may consider that the base station is capable of using a multi-TRP transmission method based on multiple DCIs.

[0471] In contrast, in the present disclosure, if the number of CORESETPoolIndex types of multiple CORESETs included in the PDCCH-configuration as high-layer signaling is 1, that is, if all CORESETs have the same CORESETPoolIndex of 0 or 1, the terminal can consider that the base station performs transmission by using a single TRP instead of using a multi-TRP transmission method based on multiple DCIs.

[0472] *Configuration of multiple PDCCH-configurations: Multiple PDCCH-configurations are configured in one BWP, and each PDCCH-configuration may include a PDCCH configuration for each TRP. That is, a list of CORESETs for each TRP and / or a list of search spaces for each TRP may be included in one PDCCH-configuration, and one or more CORESETs and one or more search spaces included in one PDCCH-configuration may correspond to a specific TRP.

[0473] *Configuration of CORESET beam / beam group: The TRP corresponding to the corresponding CORESET can be identified by the beam or beam group configured for each CORESET. For example, when the same TCI state is configured in multiple CORESETs, the corresponding CORESET can be sent through the same TRP, or the PDCCH for scheduling the PDSCH of the same TRP can be sent in the corresponding CORESET.

[0474] *Configuration of search space beam / beam group: A beam or beam group is configured for each search space, and the TRP of each search space can be identified by it. For example, when the same beam / beam group or TCI state is configured in multiple search spaces, the same TRP can send PDCCH in the corresponding search space, or the PDCCH for scheduling the PDSCH of the same TRP can be sent in the corresponding search space.

[0475] As described above, by separating the CORESET or search space for each TRP, PDSCH and HARQ-ACK can be divided for each TRP, and an independent HARQ-ACK codebook can be generated for each TRP accordingly, and independent PUCCH resources can be used.

[0476] The configuration can be independent for each cell or BWP. For example, although two different CORESETPoolIndex values ​​can be configured in the primary cell (PCell), no CORESETPoolIndex value can be configured in a specific SCell. In this case, NC-JT can be configured in the PCell, but NC-JT cannot be configured in the SCell where no CORESETPoolIndex value is configured.

[0477] The PDSCH TCI state activation / deactivation MAC-CE applicable to the multi-TRP transmission method based on multiple DCIs can follow the above Fig.16. If the CORESETPoolIndex of all CORESETs in the PDCCH-configuration as high-layer signaling is not configured for the terminal, the terminal may ignore the CORESET pool ID field 16-55 in the MAC-CE 16-50. If the terminal is capable of supporting a multi-TRP transmission method based on multiple DCIs, that is, if the CORESETs in the PDCCH-configuration as high-layer signaling have different CORESETPoolIndex, the terminal may activate the TCI state in the DCI included in the PDCCH sent in the CORESET having the same CORESETPoolIndex as the CORESET pool ID field 16-55 in the MAC-CE 16-50. For example, if the value of the CORESET pool ID field 16-55 in the MAC-CE 16-50 is 0, the TCI state in the DCI included in the PDCCH sent from the CORESET having the CORESETPoolIndex of 0 may follow the activation information of the MAC-CE.

[0478] In the case where the terminal is configured by the base station to be able to use a multi-TRP transmission method based on multiple DCIs, that is, in the case where the number of CORESETPoolIndex types of multiple CORESETs included in the PDCCH-configuration as high-layer signaling exceeds 1, or in the case where the CORESETs have different CORESETPoolIndexes, the terminal can recognize that the PDSCH scheduled by the PDCCH in the corresponding CORESETs with two different CORESETPoolIndexes has the following restrictions.

[0479] If the PDSCHs scheduled by the PDCCHs in the corresponding CORESETs with two different CORESETPoolIndex overlap with each other completely or partially, the terminal may apply the TCI states indicated by the PDCCH to different CDM groups respectively. That is, two or more TCI states may not be applicable to one CDM group.

[0480] If the PDSCHs scheduled by the PDCCHs in the corresponding CORESETs with two different CORESETPoolIndex overlap each other completely or partially, the terminal can expect the PDSCHs to have the same number of actual front-loaded DMRS symbols, the same number of actual additional DMRS symbols, actual DMRS symbols in the same positions, and the same DMRS type.

[0481] The terminal may expect that the bandwidth parts indicated by the PDCCH in the corresponding CORESETs with two different CORESETPoolIndex are the same and the subcarrier spacing is also the same.

[0482] The terminal may expect that information on the PDSCH scheduled by the PDCCH in each of the CORESETs having two different CORESETPoolIndex is fully included in the corresponding PDCCH.

[0483] [Multiple TRPs based on a single DCI]

[0484] As an embodiment of the present disclosure, a multi-TRP transmission method based on a single DCI is described. Through the multi-TRP transmission method based on a single DCI, a downlink control channel for NC-JT transmission can be configured based on a single PDCCH.

[0485] In NC-JT based on a single PDCCH, a PDSCH sent through multiple TRPs can be scheduled by one DCI. At this time, a method of indicating the number of TRPs and the number of TCI states for sending the corresponding PDSCH can be used. That is, when the number of TCI states indicated by the DCI for scheduling PDSCH is 2, NC-JT based on a single PDCCH can be considered, and when the number of TCI states is 1, single TRP transmission can be considered. The TCI state indicated by the DCI can correspond to one or two TCI states among the TCI states activated by the MAC CE. When the TCI state of the DCI corresponds to two TCI states activated by the MAC CE, the TCI code point indicated by the DCI is associated with the TCI state activated by the MAC CE, in which case the number of TCI states activated by the MACCE corresponding to the TCI code point can be 2.

[0486] As another example, if at least one code point among all code points of the TCI state field in the DCI indicates two TCI states, the terminal may consider that the base station is capable of performing transmission based on a multi-TRP transmission method based on a single DCI. At least one code point of the TCI state field indicating two TCI states may be activated by an enhanced PDSCH TCI state activation / deactivation MAC-CE.

[0487] Fig. 20 A schematic diagram of an enhanced PDSCH TCI state activation / deactivation MAC-CE structure according to an embodiment of the present disclosure is shown. The meaning of each field in the MAC CE and the available values ​​in each field may be as shown in Table 25.

[0488] [Table 25]

[0489]

[0490]

[0491] exist Fig. 20 In the case where the value of the C0 field 20-05 is 1, the MAC-CE may include the TCI state ID0,2 field 20-15 in addition to the TCI state ID0,1 field 20-10. This means that TCI state ID0,1 and TCI state ID0,2 are activated for the 0th code point of the TCI state field included in the DCI, and when the base station indicates the code point to the terminal, two TCI states may be indicated to the terminal. If the value of the C0 field 20-05 is 0, the MAC-CE cannot include the TCI state ID0,2 field 20-15, and this means that one TCI state corresponding to TCI state ID0,1 is activated for the 0th code point of the TCI state field included in the DCI.

[0492] This configuration may be independent for each cell or each BWP. For example, in the PCell, the number of activated TCI states corresponding to one TCI code point is up to 2, but in a specific SCell, the number of activated TCI states corresponding to one TCI code point may be up to 1. In this case, it can be considered that NC-JT transmission is configured in the PCell, but NC-JT transmission is not configured in the above SCell.

[0493] [Method for distinguishing multiple TRP PDSCH repetitive transmission schemes (TDM / FDM / SDM) based on a single DCI]

[0494] Next, a method for distinguishing between multiple TRP PDSCH repetition transmission schemes based on a single DCI will be described. According to the values ​​indicated by the DCI field and the high-level signaling configuration, different multi-TRP PDSCH repetition transmission schemes (e.g., TDM, FDM, and SDM) based on a single DCI can be indicated from the base station to the terminal. Table 26 below shows a method for distinguishing between single or multiple TRP-based schemes indicated to the terminal based on specific DCI field values ​​and high-level signaling configurations.

[0495] [Table 26]

[0496]

[0497]

[0498] In Table 26 above, each column can be described as follows.

[0499] Number of TCI states (second column): This indicates the number of TCI states indicated by the TCI state field in the DCI, for example, it can be one or two.

[0500] Number of CDM groups (third column): This indicates the number of different CDM groups for the DMRS ports indicated by the Antenna Ports field in the DCI. For example, the same can be 1, 2 or 3.

[0501] repetitionNumber (repetition number) configuration and indication conditions (fourth column): There can be three conditions depending on whether repetitionNumber is configured for all TDRA entries that can be indicated by the time domain resource allocation field in the DCI, and whether the actual indicated TDRA entry has a repetitionNumber configuration.

[0502] Condition 1: At least one of all TDRA entries that may be indicated by the time domain resource allocation field includes a configuration regarding repetitionNumber, and the TDRA entry indicated by the time domain resource allocation field in the DCI includes a configuration regarding a repetitionNumber greater than 1.

[0503] Condition 2: At least one of all TDRA entries indicated by the time domain resource allocation field includes a configuration regarding repetitionNumber, and the TDRA entry indicated by the time domain resource allocation field in the DCI does not include a configuration regarding repetitionNumber.

[0504] Condition 3: All TDRA entries indicated by the time domain resource allocation field do not include configuration regarding repetitionNumber.

[0505] Related to repetitionScheme configuration (fifth column): This indicates whether repetitionScheme as high-layer signaling is configured. As high-layer signaling repetitionScheme, one of "tdmSchemeA", "fdmSchemeA" and "fdmSchemeB" can be configured.

[0506] Transmission scheme indicated to the terminal (sixth column): This indicates the single or multiple TRP scheme indicated by the combination (first column) represented in Table 26 above.

[0507] Single TRP: This indicates a PDSCH transmission based on a single TRP. If the pdsch-AggegationFactor in the higher-level signaling PDSCH-config is configured for the terminal, a single TRP-based PDSCH repetitive transmission can be scheduled for the terminal for the configured number of times. Otherwise, a single PDSCH transmission based on a single TRP can be scheduled for the terminal.

[0508] Single TRP TDM Scheme B: This indicates PDSCH transmission based on inter-slot time resource partitioning based on a single TRP. According to the above condition 1 related to repetitionNumber, the number of times the terminal repeats PDSCH transmission in the time domain corresponds to the number of time slots corresponding to the count of repetitionNumber greater than 1 configured in the TDRA entry indicated by the time domain resource allocation field. The terminal applies the same symbol length and the same start symbol of the PDSCH indicated by the TDRA entry to each time slot, the number of time slots is equal to the count of repetitionNumber, and the same TCI state is applied to each PDSCH repetition transmission. This scheme is similar to the time slot aggregation scheme in that inter-slot PDSCH repetition transmission is performed in the time resource, but is different from time slot aggregation in that whether repetition transmission is indicated can be dynamically determined based on the time domain resource allocation field in the DCI.

[0509] Multi-TRP SDM: This means a PDSCH transmission scheme based on spatial resources of multiple TRPs. This is a method of receiving a distributed layer from each TRP and is not a repeated transmission scheme, but can increase the reliability of PDSCH transmission because transmission is performed at a lower code rate by increasing the number of layers. The terminal can apply the two TCI states indicated by the TCI state field in the DCI to the two CDM groups indicated by the base station, respectively, in order to receive the PDSCH.

[0510] Multi-TRP FDM Scheme A: This means a PDSCH transmission scheme based on frequency resources of multiple TRPs. This scheme provides one PDSCH transmission position (opportunity), so it is not a repeated transmission like multi-TRP SDM. However, by increasing the number of frequency resources, high-reliability transmission at a lower code rate is possible. Multi-TRP FDM Scheme A can apply two TCI states indicated by the TCI state field in the DCI to frequency resources that do not overlap with each other. In the case where the PRB bundling size is determined to be wideband, if the number of RBs indicated by the frequency domain resource allocation field is N, the terminal applies the first TCI state to the first ceil (N / 2) RBs and the second TCI state to the remaining floor (N / 2) RBs to perform reception. Here, ceil (.) and floor (.) are operators indicating rounding up and down to a decimal place. If the PRB bundling size is determined to be 2 or 4, the terminal can apply the first TCI state to the even-numbered precoding resource block group (PRG) and the second TCI state to the odd-numbered PRG to perform reception.

[0511] Multi-TRP FDM Scheme B: This means that the PDSCH repetition transmission scheme is divided based on the frequency resources of multiple TRPs, and two PDSCH transmission opportunities are provided to repeat the PDSCH transmission at the corresponding opportunities. In the same way as the multi-TRP FDM scheme A, the multi-TRP FDM scheme B can also apply the two TCI states indicated by the TCI state field in the DCI to the frequency resources that do not overlap with each other. In the case where the PRB bundling size is determined to be wideband, if the number of RBs indicated by the frequency domain resource allocation field is N, the terminal applies the first TCI state to the first ceil (N / 2) RBs and the second TCI state to the remaining floor (N / 2) RBs to perform reception. Here, ceil (.) and floor (.) are operators indicating rounding up and down to a decimal place. If the PRB bundling size is determined to be 2 or 4, the terminal may apply the first TCI state to the even-numbered PRGs and the second TCI state to the odd-numbered PRGs to perform reception.

[0512] Multi-TRP TDM scheme A: This means a PDSCH repetition transmission scheme within a time slot based on time resource division of multiple TRPs. The terminal can have two PDSCH transmission opportunities in one time slot, and can determine the first reception opportunity based on the symbol length and start symbol of the PDSCH indicated by the time domain resource allocation field in the DCI. The starting symbol of the second reception opportunity of the PDSCH can be a position obtained by applying the symbol offset of the high-level signaling StartingSymbolOffsetK (starting symbol offset K) from 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 thereof. If the high-level signaling StartingSymbolOffsetK is not configured, the symbol offset can be considered to be 0.

[0513] Multi-TRP TDM Scheme B: This means an inter-time slot PDSCH repetition transmission scheme based on time resource division of multiple TRPs. The terminal can have one PDSCH transmission opportunity in one time slot, and receive repetition transmission based on the same symbol length and the same start symbol of the PDSCH during multiple time slots corresponding to the count of the repetitionNumber indicated by the time domain resource allocation field in the DCI. If the repetitionNumber is 2, the terminal can receive PDSCH repetition transmission in the first time slot and the second time slot by applying the first TCI state and the second TCI state, respectively. If the repetitionNumber is greater than 2, the terminal can use different TCI state application schemes, and the high-level signaling tciMapping is configured according to it. If tciMapping is configured as cyclicMapping, the terminal applies the first TCI state and the second TCI state to the first PDSCH transmission opportunity and the second PDSCH transmission opportunity, respectively, and also applies the TCI state application method to the remaining PDSCH transmission opportunities in the same manner. If tciMapping is configured as sequentialMapping, the terminal applies the first TCI state to the first PDSCH transmission timing and the second PDSCH transmission timing, respectively, and applies the second TCI state to the third PDSCH transmission timing and the fourth PDSCH transmission timing, and also applies the TCI state application method to the remaining PDSCH transmission timings in the same manner.

[0514] [DMRS related]

[0515] Next, description will be given of the antenna port field indication included in DCI format 1_1 and DCI format 1_2 defined in the above Table 7. The antenna port field in DCI formats 1_1 and 1_2 may be represented by 4, 5, or 6 bits, and indication may be performed by the following Tables 27 to 34.

[0516] [Table 27]

[0517] Antenna port (1000 + DMRS port), dmrs-type = 1, maxLength = 1

[0518]

[0519] [Table 28]

[0520] Antenna port (1000+DMRS port) dmrs-typee=1, maxLength=1

[0521]

[0522] [Table 29]

[0523] Antenna port (1000+DMRS port) drms-type=1, maxLength=2

[0524]

[0525] [Table 30]

[0526] Antenna port (1000+DMRS port) drms-type=1, maxLength=2

[0527]

[0528] [Table 31]

[0529] Antenna port (1000 + DMRS port), drms-type = 2maxLength =

[0530]

[0531] [Table 32]

[0532] Antenna port (1000 + DMRS port), drms-type = 2, maxLength = 1

[0533]

[0534] [Table 33]

[0535] Antenna port (1000 + DMRS port), drms-type = 2maxLength = 2

[0536]

[0537]

[0538] [Table 34] Antenna port (1000 + DMRS port) drms-type = 2 maxLength = 2

[0539]

[0540]

[0541] Tables 27 and 28 are tables used when dmrs-type is indicated as 1 and maxLength is indicated as 1, Tables 29 and 30 are tables used when dmrs-type is equal to 1 and maxLength is equal to 2, Tables 31 and 32 show the DMRS ports used when dmrs-type is equal to 2 and maxLength is equal to 1, and Tables 33 and 34 show the DMRS ports used when dmrs-type is equal to 2 and maxLength is equal to 2.

[0542] If the terminal has received a MAC-CE for activating a code point of two TCI states indicating at least one code point of the TCI state field in the DCI, the DMRS port may be indicated to the terminal by using Table 28, Table 30, Table 32, and Table 34. Otherwise, the DMRS port may be indicated to the terminal by using Table 27, Table 29, Table 31, and Table 33. If the code point indicating two TCI states is indicated to the terminal through the TCI state field, for the purpose of NC-JT scheduling in Table 28, Table 30, Table 32, and Table 34, entries indicating DMRS ports 1000, 1002, and 1003 may be indicated to the terminal, and these entries may be entry #12 in Table 28, entry #31 in Table 30, entry #24 in Table 32, and entry #58 in Table 34.

[0543] For DCI format 1_1, if both high-level signaling dmrs-DownlinkForPDSCH-MappingTypeA (dmrs-downlink for PDSCH-mapping type A) and dmrs-DownlinkForPDSCH-MappingTypeB (dmrs-downlink for PDSCH-mapping type B) are configured for the terminal, the bit length of the antenna port field in DCI format 1_1 can be determined by max{xA,xB}. Here, xA and xB can indicate the bit length of the antenna port field determined by dmrs-DownlinkForPDSCH-MappingTypeA and dmrs-DownlinkForPDSCH-MappingTypeB, respectively. If the PDSCH mapping type corresponding to the smaller value of xA and xB is scheduled, each MSB bit equal to |xA-xB| can be assigned 0 bits and then sent.

[0544] For DCI format 1_2, if high-level signaling antennaPortsFieldPresenceDCI-1-2 is not configured for the terminal, there is no antenna port field in DCI format 1-2. That is, the length of the antenna port field is 0 bits, and the terminal can determine the DMRS port by assuming the 0th entry in Table 27, Table 29, Table 31, and Table 33. If high-level signaling antennaPortsFieldPresenceDCI-1-2 is configured for the terminal, the bit length of the antenna port field in DCI format 1_2 can be determined similarly to the case of DCI format 1_1. If both high-layer signaling dmrs-DownlinkForPDSCH-MappingTypeA-DCI-1-2 (dmrs-downlink for PDSCH-mapping type A-DCI-1-2) and dmrs-DownlinkForPDSCH-MappingTypeB-DCI-1-2 (dmrs-downlink for PDSCH-mapping type B-DCI-1-2) are configured for the terminal, the bit length of the antenna port field of DCI format 1_2 can be determined by max{xA,xB}, where xA and xB can indicate the bit length of the antenna port field determined by dmrs-DownlinkForPDSCH-MappingTypeA-DCI-1-2 and dmrs-DownlinkForPDSCH-MappingTypeB-DCI-1-2, respectively. If the PDSCH mapping type corresponding to the smaller value of xA and xB is scheduled, each of the same number of MSB bits as |xA-xB| can be allocated 0 bits and then sent.

[0545] The numbers 1, 2, and 3 indicated by the number of DMRS CDM groups without data in Tables 27 to 34 may indicate CDM groups {0}, {0, 1}, and {0, 1, 2}, respectively. The DMRS ports show the indexes of the ports used in order. The antenna port may be indicated by DMRS port + 1000. As shown in Tables 35 and 36, the CDM group of DMRS is connected to the method of generating a DMRS sequence and an antenna port. Table 35 shows the parameters for the case of using dmrs-type = 1, and Table 36 shows the parameters for the case of using dmrs-type = 2.

[0546] [Table 35]

[0547] Parameters for PDSCH DM-RS dmrs-type=1

[0548]

[0549] [Table 36]

[0550] Parameters for PDSCH DM-RS dmrs-type=2

[0551]

[0552] The DMRS sequence according to each parameter can be determined by the following equation 3. In equation 3, p represents a DMRS port, k represents a subcarrier index, 1 represents an OFDM symbol index, μ represents a subcarrier spacing, wf(k') and wt(l') represent frequency domain orthogonal cover code (FD-OCC) coefficients and time domain orthogonal cover code (TD-OCC) coefficients according to k' values ​​and 1' values, respectively, and Δ represents the spacing between CDM groups by using the number of subcarriers. In [Equation 3], is a scaling factor indicating the ratio between the energy per RE (EPRE) of PDSCH and the EPRE of DMRS and can be obtained by to calculate, and according to the number of CDM groups 1, 2 and 3, β DMRS The values ​​of can be 0dB, -3dB and -4.77dB.

[0553] [Equation 3]

[0554]

[0555] k'=0,1

[0556]

[0557] n=0,1,…

[0558] In the case of using DMRS type 1, if a single codeword is scheduled and entries #2, #9, #10, #11, and #30 are indicated to the terminal by using Table 27 or Table 29, if a single codeword is scheduled and entries #2, #9, #10, #11, and #12 are indicated to it by using Table 28, if a single codeword is scheduled and entries #2, #9, #10, #11, #30, and #31 are indicated to it by using Table 30, or if two codewords are scheduled, the terminal may consider the scheduling to be single-user MIMO scheduling. That is, the terminal may assume that different terminals are not scheduled to all remaining orthogonal DMRS ports except for the DMRS port assigned to the scheduled PDSCH, and may not expect multi-user MIMO (MU-MIMO) scheduling. In this case, the terminal does not assume that different terminals are co-scheduled, and may not perform multi-user MIMO reception operations such as eliminating, nulling, or whitening multi-user interference.

[0559] In the case of using DMRS type 2, if a single codeword is scheduled and entries #2, #10, and #23 are indicated to the terminal by using Table 31 or Table 33, if a single codeword is scheduled and entries #2, #10, #23, and #24 are indicated to it by using Table 32, if a single codeword is scheduled and entries #2, #10, #23, and #58 are indicated to it by using Table 34, or if two codewords are scheduled, the terminal may consider the scheduling to be single-user MIMO scheduling. That is, the terminal may assume that different terminals are not scheduled to all remaining orthogonal DMRS ports except for the DMRS port assigned to the scheduled PDSCH, and may not expect multi-user MIMO scheduling. In this case, the terminal does not assume that different terminals are co-scheduled, and may not perform multi-user MIMO reception operations such as eliminating, zeroing, or whitening multi-user interference.

[0560] The terminal may not expect that when the number of maximum front-loaded DMRS symbols is configured as len2 through higher-layer signaling maxLength, one or more additional DMRS symbols are configured through higher-layer signaling dmrs-AdditionalPosition.

[0561] The terminal may not expect that the actual number of front-loaded DMRS, the actual number of additional DMRS symbols, DMRS symbol positions, and DMRS type configuration are different for all terminals subject to multi-user MIMO scheduling.

[0562] In the case of a terminal with a PRG size of 2 or 4, the terminal may not expect frequency resource allocations to not match in the PRG cell grid for different terminals co-scheduled using different orthogonal DMRS ports in the same CDM group as the CDM group of DMRS ports indicated to the terminal.

[0563] In the case of scheduling PDSCH through DCI formats 1_1 and 1_2, the terminal may assume that the CDM group indicated by the column of "Number of DMRS CDM groups without data" in the above-mentioned Tables 27 to 34 may include DMRS ports allocated to different terminals that can be co-scheduled through a multi-user MIMO scheme and may not be used for data transmission of the terminal, and the values ​​1, 2 and 3 indicated by the column of "Number of DMRS CDM groups without data" in Tables 27 to 34 may mean that the indices of the CDM groups corresponding to the values ​​correspond to CDM groups 0, {0, 1} and {0, 1, 2}, respectively.

[0564] If high-layer signaling dmrs-FD-OCC-disableForRank1PDSCH is configured for the terminal and a DMRS port is allocated to the terminal for PDSCH scheduling, the terminal may not expect that different terminals are allocated DMRS ports in which different FD-OCCs are used among different orthogonal DMRS ports belonging to the same CDM group as the CDM group of an allocated DMRS port.

[0565] In one embodiment, a method of supporting enhanced DMRS Type 1 and enhanced DMRS Type 2 is described that supports an increased number of orthogonal ports.

[0566] The evolved 5G standard may support enhanced DMRS type 1 and enhanced DMRS type 2, which support an increased number of orthogonal ports while maintaining the same RE usage and the same overhead as DMRS type 1 and DMRS type 2, which are already supported in the initial 5G standard for all uplinks and downlinks. In the case of conventional DMRS type 1, if the number of front-loaded symbols is 1 and 2, up to 4 and 8 orthogonal DMRS ports may be supported, respectively, and in the case of DMRS type 2, if the number of front-loaded symbols is 1 and 2, up to 6 and 12 orthogonal DMRS ports may be supported, respectively. Referring to these supported items, in the case of enhanced DMRS type 1, if the number of front-loaded symbols is 1 and 2, up to 8 and 16 orthogonal DMRS ports may be supported, respectively, and in the case of enhanced DMRS type 2, if the number of front-loaded symbols is 1 and 2, up to 12 and 24 orthogonal DMRS ports may be supported, respectively.

[0567] Hereinafter, the new DMRS type supporting the increased number of orthogonal ports as described above may be named one of “enhanced DMRS type 1 and enhanced DMRS type 2”, “new DMRS types 1 and 2”, “new DMRS types 1 and 2”, “DMRS types 1-1 and 2-1”, and “DMRS types 3 and 4”, and other similar extended names whose meanings are enhanced functions compared to the conventional DMRS types 1 and 2 may not be excluded. In addition, the following items are mainly described for the downlink, but may also be similarly applied to uplink DMRS support.

[0568] If the terminal supports enhanced DMRS type 1 and enhanced DMRS type 2, the terminal can report the terminal capability of supporting enhanced DMRS type 1 and enhanced DMRS type 2 to the base station. The report of terminal capability can be sent to the base station by frequency band, more specifically, by feature set (FS) (by frequency band per frequency band combination) or by feature set (FSPC) per component carrier (by CC per frequency band per frequency band combination). In addition, the reporting of terminal capabilities can be supported differently for each frequency range (FR) or can be limited to FR1 (for example, below 6gHz). In addition, the reporting of terminal capabilities can include the meaning as described above, where in the case of enhanced DMRS type 1, if the number of symbols loaded in the front is 1 and 2, a maximum of 8 and 16 orthogonal DMRS ports can be supported, respectively, and in the case of enhanced DMRS type 2, if the number of symbols loaded in the front is 1 and 2, a maximum of 12 and 24 orthogonal DMRS ports can be supported, respectively. The terminal may perform reporting through a common terminal capability for enhanced DMRS type 1 and enhanced DMRS type 2, and may report whether the terminal supports only enhanced DMRS type 1, only enhanced DMRS type 2, or both enhanced DMRS type 1 and enhanced DMRS type 2. Alternatively, the terminal may report whether the terminal supports each of enhanced DMRS type 1 and enhanced DMRS type 2 through separate terminal capabilities.

[0569] In addition, if the terminal supports the dynamic switching function between the enhanced DMRS type and the traditional DMRS type, the terminal can report the function through the terminal capability. The dynamic switching function between the enhanced DMRS type and the traditional DMRS type can mean that the DMRS type configured by the high-layer signaling can be changed by MAC-CE, the selection between the enhanced type and the traditional type is possible through DCI, or both. If the terminal reports whether to support enhanced DMRS type 1 and enhanced DMRS type 2 through a common terminal capability report, the terminal can support the dynamic switching function of DMRS type 1 and DMRS type 2 through a terminal capability report, and report whether the terminal only supports dynamic switching between DMRS type 1 and enhanced DMRS type 1, whether the terminal only supports dynamic switching between DMRS type 2 and enhanced DMRS type 2, or whether the terminal supports dynamic switching between two types of enhanced types and traditional types. In contrast, in the case where the terminal reports whether to support enhanced DMRS type 1 and enhanced DMRS type 2 through a common terminal capability or a separate terminal capability report, the terminal can be possible to dynamically switch between the traditional type and the enhanced type through a separate terminal capability report for each type.

[0570] In addition, in the case where the terminal operates in enhanced DMRS type 1 or enhanced DMRS type 2, if the terminal supports legacy DMRS type 1 or legacy DMRS type 2 and multi-user MIMO scheduling, the terminal may report the functionality through terminal capabilities. Multi-user MIMO scheduling may indicate co-scheduling between legacy DMRS type 1 and enhanced DMRS type 1, or co-scheduling between legacy DMRS type 2 and enhanced DMRS type 2. Similar to the above description, terminal capabilities related to whether co-scheduling between legacy DMRS types and enhanced DMRS types is possible may be reported through common terminal capabilities. For example, the terminal may report that co-scheduling between only legacy type 1 and enhanced type 1 is possible, report that co-scheduling between only legacy type 2 and enhanced type 2 is possible, or report that co-scheduling between legacy type and enhanced type is possible for both type 1 and type 2. Alternatively, the terminal may perform reporting through separate terminal capabilities for each type.

[0571] For a terminal that has reported its terminal capabilities, the base station may use the following method to configure enhanced DMRS type 1 and enhanced DMRS type 2 schemes for the terminal through high-layer signaling.

[0572] -[High-layer configuration method 1] For example, the high-layer signaling DMRS-DownlinkConfig (DMRS-downlink configuration) can be used to configure the supported enhanced DMRS type for the terminal.

[0573] [High-level configuration method 1-1] A high-level signaling dmrs-Type-r18 (dmrs-type-r18) similar to the high-level signaling dmrs-Type used to determine the traditional DMRS type can be configured, and dmrs-Type-r18 can be used to define an enhanced DMRS type other than DMRS type 1 or DMRS type 2. The RRC IE referred to as dmrs-Type-r18 in addition to dmrs-Type can be newly configured to the terminal in the high-level signaling DMRS-DownlinkConfig. Through dmrs-Type-r18, one of a total of four different DMRS types can be configured, including DMRS type 1 and DMRS type 2 and enhanced DMRS type 1 and enhanced DMRS type 2, or one of enhanced DMRS type 1 and enhanced DMRS type 2 can be configured. For example, as shown in Table 37 below, if dmrs-Type-r18 is configured, one of DMRS type 2, enhanced DMRS type 1, and enhanced DMRS type 2 can be configured, 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. As another example, if dmrs-Type-r18 is configured, one of enhanced DMRS type 1 and enhanced DMRS type 2 can be configured, 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. If the base station configures high-layer signaling for the terminal by using [High-layer configuration method 1-1], one of a total of four schemes including DMRS type 1, DMRS type 2, enhanced DMRS type 1 and enhanced DMRS type 2 can be configured for the terminal for each of PDSCH mapping types A or B. In another method, if the base station configures high-level signaling for the terminal by using [high-level configuration method 1-1], for each of PDSCH mapping types A or B, the terminal can be configured with a traditional scheme (e.g., DMRS type 1 or DMRS type 2) and an enhanced scheme (e.g., enhanced DMRS type 1 or enhanced DMRS type 2) including a DMRS type. One of a total of two schemes, and this can be a high-level configuration scheme, in which dynamic switching between the traditional scheme and the enhanced scheme is not possible, or dynamic switching is not considered. DMRS-Type-r18, which is the name of the RRC IE, is only an example and may be different from the name of the actual RRC IE.

[0574] [Table 37]

[0575]

[0576] [High-level configuration method 1-2] Although the traditional meaning of the existing dmrs-Type in which one of DMRS type 1 and DMRS type 2 is determined is used, a new RRC IE (e.g., enhanced-Dmrs-Type-r18) having the meaning of whether enhanced DMRS type 1 or enhanced DMRS type 2 is available can be additionally configured. As shown in Table 38 below, if the base station does not configure the high-level signaling dmrs-Type for the terminal and does not configure enhanced-Dmrs-Type-r18 for it, the terminal can support the traditional scheme for DMRS type 1. In addition, if the dmrs-Type is not configured for the terminal and enhanced-Dmrs-Type-r18 is configured to be enabled, this may mean that the terminal can support the enhanced scheme of DMRS type 1. In this case, when the terminal supports dynamic switching between traditional types and enhanced types, if enhanced-Dmrs-Type-r18 is configured for the terminal, the terminal can perform dynamic switching without additional high-layer signaling, or whether to perform dynamic switching can be configured by the base station for the terminal through dynamicSwitchType (dynamic switching type) as additional high-layer signaling.

[0577] [Table 38]

[0578]

[0579] [High-level configuration method 2] The terminal may not use the high-level signaling DMRS-DownlinkConfig to support the enhanced DMRS type, and the supported enhanced DMRS type may be configured separately for the terminal to the high-level signaling through the new RRC IE (e.g., enhanced-Dmrs-Type-r18) in the PDSCH-Config. As shown in Table 39 below, if the base station does not configure the high-level signaling enhanced-Dmrs-Type-r18 for the terminal, the terminal may determine the DMRS type as the existing DMRS-DownlinkConfig configuration. If the base station configures the high-level signaling enhanced-Dmrs-Type-r18 for the terminal, the terminal may use an enhanced scheme of the DMRS type determined according to the existing DMRS-DownlinkConfig configuration. In this case, if the terminal supports dynamic switching between the traditional type and the enhanced type, if enhanced-Dmrs-Type-r18 is configured for the terminal, the terminal may perform dynamic switching without additional high-level signaling, or whether to perform dynamic switching may be configured by the base station for the terminal through dynamicSwitchType as additional high-level signaling.

[0580] [Table 39]

[0581]

[0582] Hereinafter, various supporting methods for determining specific RE mapping and OCC for enhanced DMRS type 1 and enhanced DMRS type 2 will be described.

[0583] [Enhanced DMRS Type 1 Support Method 1]

[0584] As an embodiment of the above-mentioned method for supporting enhanced DMRS type 1, the time and frequency resource mapping of DMRS RE when using enhanced DMRS type 1 and the frequency domain orthogonal cover code (FD-OCC) coefficients and time domain orthogonal cover code (TD-OCC) coefficients used for mapping can be determined based on the following [Equation 4] and Table 40.

[0585] [Equation 4]

[0586]

[0587] k=8n+4k′+Δ (for new DMRS type 1)

[0588] k′=0,1

[0589]

[0590] n=0,1,...

[0591] Δ=0,1,2,3

[0592] Table 40 shows parameters for [enhanced DMRS type 1 support method 1] according to an embodiment of the present disclosure.

[0593] [Table 40]

[0594]

[0595] In [Enhanced DMRS Type 1 Support Method 1] based on the above [Equation 4] and Table 40, a total of four CDM groups are used. In the case of one front-loaded DMRS symbol, two DMRS ports can be included in each CDM group, so a total of eight orthogonal DMRS ports can be supported, and in the case of two front-loaded DMRS symbols, four DMRS ports can be included in each CDM group, so a total of sixteen orthogonal DMRS ports can be supported. Compared to the interval of two REs between REs allocated to a specific DMRS port in the same CDM group in the conventional DMRS type 1, since four CDM groups are supported, the interval can be increased to four REs. The number of CDM groups is increased while maintaining the number of DMRS ports in each CDM group, so the scheduling of PDSCH transmitted together with DMRS can be limited to units of two RBs. In [Equation 4], is a scaling factor indicating the ratio between the energy per RE (EPRE) of PDSCH and the EPRE of DMRS and can be obtained by is calculated, and according to the number of CDM groups 1, 2, 3 and 4, β DMRS The values ​​of can be 0dB, -3dB, -4.77dB and -6dB.

[0596] [Enhanced DMRS Type 1 Support Method 2]

[0597] As another embodiment of the above-mentioned method of supporting enhanced DMRS type 1, the time and frequency resource mapping of DMRS RE when using enhanced DMRS type 1 and the FD-OCC coefficients and TD-OCC coefficients used for mapping can be determined based on the following [Equation 5] and Table 41.

[0598] [Equation 5]

[0599]

[0600] k = 8n + 2k' + Δ (for new DMRS type 1)

[0601] k'=0,1

[0602]

[0603] n=0,1,...

[0604] Table 41 shows parameters for [enhanced DMRS type 1 support method 2] according to an embodiment of the present disclosure.

[0605] [Table 41]

[0606]

[0607] In [Enhanced DMRS Type 1 Support Method 2] based on [Equation 5] and Table 41 above, a total of four CDM groups are used. In the case of one front-loaded DMRS symbol, two DMRS ports can be included in each CDM group, so a total of eight orthogonal DMRS ports can be supported, and in the case of two front-loaded DMRS symbols, four DMRS ports can be included in each CDM group, so a total of sixteen orthogonal DMRS ports can be supported. The number of CDM groups is increased while maintaining the number of DMRS ports in each CDM group, so the scheduling of PDSCH transmitted with DMRS can be limited to units of two RBs. As in conventional DMRS type 1, the interval between REs allocated to a specific DMRS port in the same CDM group is maintained at two REs. However, for each DMRS port, the DMRS density of a specific RB among the two RBs may be high, while the DMRS density of the other RB may be low. For example, in the case of DMRS ports 1000 to 1003, the DMRS density of even-numbered RBs among the allocated RBs is twice that of odd-numbered RBs, but in the case of DMRS ports 1004 to 1008, the opposite may occur. In [Equation 5], is a scaling factor indicating the ratio between the energy per RE (EPRE) of PDSCH and the EPRE of DMRS and can be obtained by is calculated, and according to the number of CDM groups 1, 2, 3 and 4, β DMRS The values ​​of can be 0dB, -3dB, -4.77dB and -6dB.

[0608] [Enhanced DMRS Type 1 Support Method 3]

[0609] As another embodiment of the above-mentioned method for supporting enhanced DMRS type 1, the time and frequency resource mapping of DMRS RE in the case of using enhanced DMRS type 1 and the FD-OCC coefficient and TD-OCC coefficient used for mapping can be determined based on the above [Equation 3] and the following Table 42. Unlike the conventional DMRS type 1, for the even-numbered RBs to which the PDSCH is scheduled, indication of DMRS ports 1000 to 1007 is possible, and for the odd-numbered RBs, indication of DMRS ports 1008 to 1015 is possible. Therefore, as shown in the following Table 42, when the indexes of the DMRS ports differ from each other by 8 indexes, the FD-OCC coefficient and the TD-OCC coefficient are the same. Alternatively, although only the indication of DMRS ports 1000 to 1007 is supported using the above-mentioned Table 35, which RB among the even-numbered RBs and the odd-numbered RBs in which the DMRS RE is arranged in the frequency resources to which the PDSCH is scheduled is additionally indicated. Therefore, a method of distinguishing the same DMRS port 1000 according to the RB in which the DMRS RE is arranged may also be used. A specific DMRS port indication and RB position indication method will be described later.

[0610] Table 42 shows parameters for [enhanced DMRS type 1 support method 3] according to an embodiment of the present disclosure.

[0611] [Table 42]

[0612]

[0613] In [Enhanced DMRS Type 1 Support Method 3] based on [Equation 3] and Table 42 above, a total of two CDM groups are used. In the case of one front-loaded DMRS symbol, two DMRS ports can be included in each CDM group, and the DMRS ports are divided to be allocated to even-numbered RBs and odd-numbered RBs, so a total of eight orthogonal DMRS ports can be supported, and in the case of two front-loaded DMRS symbols, four DMRS ports can be included in each CDM group, so a total of sixteen orthogonal DMRS ports can be supported. While the DMRS is divided to be allocated to even-numbered RBs and odd-numbered RBs, the number of DMRS ports in each CDM group and the number of CDM groups are maintained, so the scheduling of the PDSCH transmitted together with the DMRS can be limited to units of three or more RBs.

[0614] [Enhanced DMRS Type 1 Support Method 4]

[0615] As another embodiment of the above-mentioned method of supporting enhanced DMRS type 1, the time and frequency resource mapping of DMRS RE when using enhanced DMRS type 1 and the FD-OCC coefficients and TD-OCC coefficients used for mapping can be determined based on [Equation 5-1] and the following Table 43.

[0616] [Equation 5-1]

[0617]

[0618] k = 12n + 2k' + Δ (for new DMRS type 1)

[0619] k′=0,1,2,3,4,5

[0620]

[0621] n=0,1,...

[0622] Table 43 shows parameters for [enhanced DMRS type 1 support method 4] according to an embodiment of the present disclosure.

[0623] [Table 43]

[0624]

[0625] In [Enhanced DMRS Type 1 Support Method 4] based on [Equation 5-1] and Table 43 above, a total of two CDM groups are used. In the case of one front-loaded DMRS symbol, four DMRS ports can be included in each CDM group, and in the case of two front-loaded DMRS symbols, eight DMRS ports can be included in each CDM group, so a total of sixteen orthogonal DMRS ports can be supported. The number of DMRS ports in each CDM group increases, while the number of CDM groups of the conventional DMRS type 1 remains at 2. Therefore, the scheduling of the PDSCH transmitted together with the DMRS can be maintained in the unit of one RB, as in the conventional unit, and the DMRS can be mapped to the same RE position as the conventional DMRS type 1. However, in the conventional DMRS type 1, under the assumption that the channels of two REs (e.g., RE#0 and RE#2) located two REs apart from each other are the same, OCC is applied to the two REs to distinguish the orthogonal ports, and in the case of one front-loaded DMRS symbol, a total of six REs in one RB are used per port, and three OCCs of length 2 are used. If [Enhanced DMRS Type 1 Support Method 4] is used, in the case of a front-loaded DMRS symbol, a total of six REs in one RB are used per port, and an OCC of length 6 is used to distinguish a total of four orthogonal ports. An OCC of length 6 is applied to six REs, and adjacent REs can be separated by two REs from each other. That is, assuming that six REs whose relative RE positions are 0, 2, 4, 6, 8 and 10 belong to the same channel, OCC needs to be applied to these six REs, so the channel estimation performance may be reduced compared to the traditional DMRS type 1. Therefore, this enhanced DMRS type 1 can be used for multi-user MIMO in channels with small frequency-selective characteristics. In Table 43 above, the values ​​of A, B and C in the OCC of length 6 can be determined so that all ports are orthogonal. For example, A=1, B=e 2π / 3 , C=e 4π / 3 It may be possible, and other values ​​are not excluded. The values ​​of A, B, and C may be predefined in the standard and agreed upon between the base station and the terminal, may be configured for the terminal through high-layer signaling, may be activated to the terminal through MAC-CE, may be dynamically indicated to the terminal through DCI, and may be notified to the terminal through a combination of these signaling. In [Equation 5-1], is a scaling factor indicating the ratio between the energy per RE (EPRE) of PDSCH and the EPRE of DMRS and can be obtained by to calculate, and according to the number of CDM groups 1 and 2, β DMRS The possible values ​​are 0dB and -3dB.

[0626] [Enhanced DMRS Type 1 Support Method 5]

[0627] As another embodiment of the above-mentioned method of supporting enhanced DMRS type 1, the time and frequency resource mapping of DMRS RE when using enhanced DMRS type 1 and the FD-OCC coefficients and TD-OCC coefficients used for mapping can be determined based on the following [Equation 5-2] and Table 44.

[0628] [Equation 5-2]

[0629]

[0630] k = 4n + 2k′ + Δ (for new DMRS type 1)

[0631] k'=0,1

[0632]

[0633] n=0,1,...

[0634] m=mod(n,3)

[0635] Table 44 shows parameters for [enhanced DMRS type 1 support method 5] according to an embodiment of the present disclosure.

[0636] [Table 44]

[0637]

[0638] In [Enhanced DMRS Type 1 Support Method 5] based on [Equation 5-2] and Table 44 above, a total of two CDM groups are used. In the case of one front-loaded DMRS symbol, four DMRS ports can be included in each CDM group, and in the case of two front-loaded DMRS symbols, eight DMRS ports can be included in each CDM group, so a total of sixteen orthogonal DMRS ports can be supported. The number of DMRS ports in each CDM group increases, while the number of CDM groups of the conventional DMRS type 1 remains at 2. Therefore, the scheduling of the PDSCH transmitted together with the DMRS can be maintained in the unit of one RB, as in the conventional unit, and the DMRS can be mapped to the same RE position as the conventional DMRS type 1. However, in the conventional DMRS type 1, under the assumption that the channels of two REs (e.g., RE#0 and RE#2) located two REs apart from each other are the same, OCC is applied to the two REs to distinguish the orthogonal ports, and in the case of one front-loaded DMRS symbol, a total of six REs in one RB are used per port, and three OCCs of length 2 are used. If [Enhanced DMRS Type 1 Support Method 5] is used, in the case of a front-loaded DMRS symbol, a total of six REs in one RB are used per port, and an OCC of length 6 is used to distinguish a total of four orthogonal ports. An OCC of length 6 is applied to six REs, and adjacent REs can be separated by two REs from each other. That is, assuming that six REs whose relative RE positions are 0, 2, 4, 6, 8 and 10 belong to the same channel, OCC needs to be applied to these six REs, so the channel estimation performance may be reduced compared to the traditional DMRS type 1. Therefore, this enhanced DMRS type 1 can be used for multi-user MIMO in channels with small frequency selectivity characteristics. In Table 44 above, the values ​​of A, B and C in the OCC of length 6 can be determined so that all ports are orthogonal. For example, A=1, B=e 2π / 3 , C=e 4π / 3 It may be possible, and other values ​​are not excluded. The values ​​of A, B, and C may be predefined in the standard and agreed upon between the base station and the terminal, may be configured for the terminal through high-layer signaling, may be activated to the terminal through MAC-CE, may be dynamically indicated to the terminal through DCI, and may be notified to the terminal through a combination of these signaling. In [Equation 5-2], is a scaling factor indicating the ratio between the energy per RE (EPRE) of PDSCH and the EPRE of DMRS and can be obtained by to calculate, and according to the number of CDM groups 1 and 2, β DMRS The possible values ​​are 0dB and -3dB.

[0639] [Enhanced DMRS Type 2 Support Method 1]

[0640] As an embodiment of the above-mentioned method of supporting enhanced DMRS type 2, the time and frequency resource mapping of DMRS RE when using enhanced DMRS type 2 and the FD-OCC coefficients and TD-OCC coefficients used for mapping can be determined based on the following [Equation 6] and Table 45.

[0641] [Equation 6]

[0642]

[0643] k = 12n + k′ + Δ (for new DMRS type 2)

[0644] k'=0,1,2,3

[0645]

[0646] n=O,1,...

[0647] Table 45 shows parameters for [enhanced DMRS type 2 support method 1] according to an embodiment of the present disclosure.

[0648] [Table 45]

[0649]

[0650] In [Enhanced DMRS Type 2 Support Method 1] based on [Equation 6] and Table 45 above, a total of three CDM groups are used. In the case of one front-loaded DMRS symbol, four DMRS ports can be included in each CDM group, so a total of twelve orthogonal DMRS ports can be supported, and in the case of two front-loaded DMRS symbols, eight DMRS ports can be included in each CDM group, so a total of twenty-four orthogonal DMRS ports can be supported. The number of DMRS ports in each CDM group increases, while the number of CDM groups is maintained, so that the scheduling of PDSCH transmitted with DMRS can be maintained in the unit of one RB, the same as the conventional unit. However, the position of DMRS RE is concentrated at a specific position in the RB, so that the DMRS channel estimation performance can be ensured when scheduling PDSCH of two or more RBs. For example, the RE positions in each RB of DMRS ports 1000 to 1003 in CDM group 0 correspond to the 0th to 4th subcarriers, so the DMRS is concentrated only on the subcarriers with low indexes in the RB. Therefore, the DMRS channel estimation performance for subcarriers with high indexes may be reduced. In [Equation 6], is a scaling factor indicating the ratio between the energy per RE (EPRE) of PDSCH and the EPRE of DMRS and can be obtained by to calculate, and according to the number of CDM groups 1, 2 and 3, β DMRS The values ​​of can be 0dB, -3dB and -4.77dB.

[0651] [Enhanced DMRS Type 2 Support Method 2]

[0652] As another embodiment of the above-mentioned method for supporting enhanced DMRS type 2, the time and frequency resource mapping of DMRS RE in the case of using enhanced DMRS type 2 and the FD-OCC coefficient and TD-OCC coefficient used for mapping can be determined based on the above [Equation 3] and the following Table 46. Similar to the above-mentioned [Enhanced DMRS Type 1 Support Method 3], unlike the traditional DMRS type 2, for the even-numbered RBs to which the PDSCH is scheduled, the indication of DMRS ports 1000 to 1011 is possible, and for the odd-numbered RBs, the indication of DMRS ports 1012 to 1023 is possible. Therefore, as shown in the following Table 46, when the indexes of the DMRS ports differ from each other by 12 indexes, the FD-OCC coefficient and the TD-OCC coefficient are the same. Alternatively, although only the indication of DMRS ports 1000 to 1011 is supported using the above-mentioned Table 36, which RB among the even-numbered RBs and the odd-numbered RBs in which the DMRS RE is arranged in the frequency resources to which the PDSCH is scheduled is additionally indicated. Therefore, a method of distinguishing the same DMRS port 1000 according to the RB in which the DMRS RE is arranged may also be used. A specific DMRS port indication and RB position indication method will be described later.

[0653] Table 46 shows parameters for [enhanced DMRS type 2 support method 2] according to an embodiment of the present disclosure.

[0654] [Table 46]

[0655]

[0656] In [Enhanced DMRS Type 2 Support Method 2] based on the above [Equation 3] and Table 46, a total of three CDM groups are used. In the case of one front-loaded DMRS symbol, two DMRS ports can be included in each CDM group, and the DMRS ports are divided to be allocated to even-numbered RBs and odd-numbered RBs, so a total of twelve orthogonal DMRS ports can be supported, and in the case of two front-loaded DMRS symbols, four DMRS ports can be included in each CDM group, so a total of twenty-four orthogonal DMRS ports can be supported. While the DMRS is divided to be allocated to even-numbered RBs and odd-numbered RBs, the number of DMRS ports in each CDM group and the number of CDM groups are maintained, so the scheduling of the PDSCH transmitted together with the DMRS can be limited to units of three or more RBs.

[0657] [Enhanced DMRS Type 2 Support Method 3]

[0658] The time and frequency resource mapping of DMRSRE in the case of using enhanced DMRS type 2 and the FD-OCC coefficient and TD-OCC coefficient used for mapping can be determined based on the following [Equation 7] and Table 47.

[0659] [Equation 7]

[0660]

[0661] k′=0,1,2,3

[0662]

[0663] n=0,1,…

[0664] Table 47 shows parameters for [enhanced DMRS type 2 support method 3] according to an embodiment of the present disclosure.

[0665] [Table 47]

[0666]

[0667] In [Enhanced DMRS Type 2 Support Method 3] based on [Equation 7] and Table 47 above, a total of three CDM groups are used. In the case of one front-loaded DMRS symbol, four DMRS ports can be included in each CDM group, so a total of twelve orthogonal DMRS ports can be supported, and in the case of two front-loaded DMRS symbols, eight DMRS ports can be included in each CDM group, so a total of twenty-four orthogonal DMRS ports can be supported. The number of DMRS ports in each CDM group increases, while the number of CDM groups is maintained. Therefore, the scheduling of the PDSCH transmitted together with the DMRS can be maintained in the unit of one RB, as in the conventional unit, and the DMRS can be mapped to the same RE position as the conventional DMRS type 2. However, in the conventional DMRS type 2, under the assumption that the channels of two consecutive REs are the same, OCC is applied to the two REs to distinguish the orthogonal ports, and in the case of one front-loaded DMRS symbol, a total of four REs in one RB are used per port, and two OCCs of length 2 are used. If [Enhanced DMRS Type 2 Support Method 3] is used, in the case of a front-loaded DMRS symbol, a total of four REs in one RB are used per port, and an OCC of length 4 is used to distinguish a total of four orthogonal ports. That is, an OCC of length 4 is applied to two consecutive RE sets separated by 6 REs from each other, that is, under the assumption that four REs whose relative RE positions are 0, 1, 6, and 7 belong to the same channel, it is necessary to apply the OCC to these four REs, so the channel estimation performance may be degraded compared to the conventional DMRS Type 2. Therefore, this enhanced DMRS Type 2 can be used for multi-user MIMO in a channel with small frequency selectivity characteristics. In [Equation 7], is a scaling factor indicating the ratio between the energy per RE (EPRE) of PDSCH and the EPRE of DMRS and can be obtained by to calculate, and according to the number of CDM groups 1, 2 and 3, β DMRS The values ​​of can be 0dB, -3dB and -4.77dB.

[0668] Regarding the above-mentioned [Enhanced DMRS Type 1 Support Method 1] to [Enhanced DMRS Type 1 Support Method 5] and [Enhanced DMRS Type 2 Support Method 1] to [Enhanced DMRS Type 2 Support Method 3], the terminal can report to the base station the terminal capability that means each support method is a possible terminal capability. The terminal capability can be valid only for FR1, or for both FR1 and FR2. The terminal capability may include the following meanings, where as the maximum number of supported ports, for enhanced DMRS type 1, eight ports are possible when one front-loaded DMRS symbol is used, and sixteen ports are possible when two front-loaded DMRS symbols are used, and for enhanced DMRS type 2, twelve ports are possible when one front-loaded DMRS symbol is used, and twenty-four ports are possible when two front-loaded DMRS symbols are used. After receiving the terminal capability, the base station can configure the corresponding high-level signaling, which can be one of the above-mentioned high-level signaling configuration methods or an independent high-level signaling.

[0669] In one embodiment, a method is disclosed for determining multiple DMRS types by a base station and a terminal based on a terminal capability report and a high-layer signaling, for which dynamic switching indication is possible. As described herein, a 5G NR terminal may support DMRS type 1 and DMRS type 2, and a terminal supporting Release 18 may support enhanced DMRS type 1 and enhanced DMRS type 2, which includes one or more more evolved functions beyond Release 18, and enhanced types 1 and 2 are capable of supporting additional orthogonal ports of DMRS types 1 and 2, respectively. The base station and the terminal may determine multiple DMRS types for which dynamic switching indication is possible among some or all of DMRS type 1, DMRS type 2, enhanced DMRS type 1, and enhanced DMRS type 2 by the following various methods.

[0670] [Method 2-1]

[0671] One of a total of four DMRS types including DMRS type 1, DMRS type 2, enhanced DMRS type 1, and enhanced DMRS type 2 can be dynamically indicated to the terminal by the base station. In this case, the base station can dynamically indicate one of the four DMRS types to the terminal, so the base station can have the highest scheduling flexibility for the terminal. On the other hand, the terminal does not know which of the four DMRS types will be dynamically indicated by the base station, so it may be necessary to prepare an independent channel estimation scheme for each of the four DMRS types when scheduling the PDSCH and PUSCH of the base station. Therefore, from the perspective of the system, the advantage is that the highest scheduling flexibility is ensured for the scheduling of a specific terminal in a single-user MIMO scheme and the scheduling of multiple terminals in a multi-user MIMO scheme, which reflects the situation and scenario of the terminal served by the base station. However, the number of channel estimation schemes for different DMRS types that the terminal needs to prepare increases from 2 to a maximum of 4, so the burden on the terminal may increase.

[0672] [Method 2-2]

[0673] One of the two DMRS types including DMRS type 1 and enhanced DMRS type 1 can be dynamically indicated to the terminal by the base station. Alternatively, similarly, one of the two DMRS types including DMRS type 2 and enhanced DMRS type 2 can be dynamically indicated to it by the base station. After one of DMRS type 1 and DMRS type 2 is configured for the terminal and the enhanced DMRS type 1 or enhanced DMRS type 2 as a method enhanced therefrom is configured for the terminal, one of the two methods including the conventional scheme and the enhanced scheme of type 1 can be indicated to the terminal, or one of the two methods including the conventional scheme and the enhanced scheme of type 2 can be indicated to it. In the conventional standard, dynamic switching indication for DMRS type 1 and DMRS type 2 is possible through time domain resource allocation in DCI. However, if the enhanced DMRS type is configured for the terminal and the terminal uses [method 2-2], the terminal may only be able to perform dynamic switching between the two methods including the conventional scheme and the enhanced scheme of a specific type as described above, and may not expect dynamic switching between types 1 and 2 that are different from each other.

[0674] [Method 2-3]

[0675] The terminal always supports DMRS type 1 and can support additional X different DMRS types, so the base station can perform dynamic switching indications for a total of (X+1) DMRS types. The PDSCH with DCI format 1_0 scheduled by the base station is DMRS type 1, so the terminal may be required to be prepared to support DMRS type 1. In addition, the terminal can also support X (for example, X∈{1, 2, 3}) types among DMRS type 2, enhanced DMRS type 1 and enhanced DMRS type 2, and the X types can be reported through terminal capabilities. According to the X types reported by the terminal, the base station can configure additional DMRS types for the terminal, and the terminal can receive dynamic switching indications for (X+1) DMRS types configured through high-level signaling.

[0676] In one embodiment, a method for dynamically switching among multiple DMRS types configured by a base station through high-layer signaling based on a terminal capability report of a terminal is disclosed. If the base station is only capable of scheduling enhanced DMRS type 1 or enhanced DMRS type 2 to the terminal, and does not support dynamic switching to traditional DMRS type 1 or DMRS type 2, when the terminal experiences a frequency selective channel, due to the characteristics of the OCC application scheme and RE mapping of enhanced DMRS type 1 or enhanced DMRS type 2, the channel estimation performance may be reduced. The main support scenario of enhanced DMRS type 1 or enhanced DMRS type 2 is multi-user MIMO scheduling with other terminals. Therefore, in a channel environment suitable for single-user MIMO scheduling with a large number of layers, the terminal may need to switch to a traditional DMRS type. However, if such a conversion is supported in a semi-static configuration scheme based on high-layer signaling, delays will inevitably occur, and the possibility of performance degradation for specific terminals and systems may therefore arise. To this end, a scheme for dynamic switching among multiple DMRS types may be required.

[0677] The following methods may be applied to at least one of the above-mentioned [Method 2-1] to [Method 2-3], and these methods may not be limited to being applied to only specific methods or not being applied to specific methods.

[0678] [Method 3-1] Scheme based on the Time Domain Resource Allocation (TDRA) field in DCI

[0679] The terminal can support dynamic switching between traditional DMRS types and enhanced DMRS types based on the time domain resource allocation field in the DCI that schedules PDSCH or PUSCH. Among the values ​​that can be indicated by the entries in the time domain resource allocation field, the DMRS type can be indicated by the PDSCH mapping type or the PUSCH mapping type. More specifically, the PDSCH mapping type (e.g., type A or type B) or the PUSCH mapping type (e.g., type A or type B) can be indicated to the terminal through the time domain resource allocation field in the DCI, and there may be a DMRS type configured to correspond to PDSCH mapping type A or PDSCH mapping type B or PUSCH mapping type A or PUSCH mapping type B. Traditionally, one of DMRS type 1 and DMRS type 2 may be configured to correspond to PDSCH mapping type A or PDSCH mapping type B, or PUSCH mapping type A or PUSCH mapping type B. For example, DMRS type 1 is configured for PDSCH mapping type A or PUSCH mapping type A, and DMRS type 2 is configured for PDSCH mapping type B or PUSCH mapping type B, and if the base station indicates PDSCH or PUSCH mapping type A through the time domain resource allocation field in the DCI, the terminal can assume that DMRS type 1 has been applied to the scheduled PDSCH or PUSCH.

[0680] Similarly, considering two additional DMRS types including enhanced DMRS type 1 and enhanced DMRS type 2, one of a total of four types including DMRS type 1, DMRS type 2, enhanced DMRS type 1, and enhanced DMRS type 2 may be configured for PDSCH mapping type A or PUSCH mapping type A. Similarly, one of the four types may also be configured for PDSCH mapping type B or PUSCH mapping type B. Depending on whether each entry in the time domain resource allocation field in the DCI indicates mapping type A or mapping type B, dynamic switching indication for a total of two types of the four types is possible.

[0681] As another method, each entry in the time domain resource allocation field in the DCI may indicate PDSCH or PUSCH mapping type A or B, and additionally indicate the DMRS type connected thereto. If four different DMRS types are configured for the terminal through high-layer signaling, including DMRS type 1, DMRS type 2, enhanced DMRS type 1, and enhanced DMRS type 2, the PDSCH or PUSCH mapping type A or B may have up to four connected DMRS types. For example, entries 1 to 4 of the time domain resource allocation field in the DCI may indicate PDSCH or PUSCH mapping type A, and DMRS type 1, DMRS type 2, enhanced DMRS type 1, and enhanced DMRS type 2 may be connected thereto, respectively, and entries 5 to 8 may indicate PDSCH or PUSCH mapping type B, and DMRS type 1, DMRS type 2, enhanced DMRS type 1, and enhanced DMRS type 2 may be connected thereto, respectively.

[0682] As another method, each entry in the time domain resource allocation field in the DCI may indicate PDSCH or PUSCH mapping type A or B, and there may be a DMRS type connected to PDSCH or PUSCH mapping type A or B through traditional high-level signaling. One of type A and type B may be configured for each entry in the time domain resource allocation field in the DCI through mappingType in high-level signaling PDSCH-TimeDomainResourceAllocation (PDSCH-time domain resource allocation) or PUSCH-TimeDomainResourceAllocation (PUSCH-time domain resource allocation), and one of the configured types among type A and type B may be indicated by the entry for application, and the DMRS type connected thereto may be applied. The base station may additionally configure whether the enhanced DMRS type is applied for the terminal in the above-mentioned high-level signaling for each entry. In the case where type A is configured for configuration of a specific entry in the time domain resource allocation field through mappingType in high-level signaling PDSCH-TimeDomainResourceAllocation or PUSCH-TimeDomainResourceAllocation, DMRS type 1 is connected to type A, and high-level signaling meaning whether to apply an enhanced DMRS type is configured, if the entry is indicated to the terminal through the time domain resource allocation field in the DCI, the terminal can interpret the scheduling information by assuming PDSCH or PUSCH mapping type A and enhanced DMRS type 1, and receive PDSCH or send PUSCH according to the interpretation.

[0683] [Method 3-2] Scheme based on specific entries in the table used in the antenna port field in DCI

[0684] The terminal can support dynamic switching between the legacy DMRS type and the enhanced DMRS type according to the value indicated by the antenna port field in the DCI scheduling the PDSCH or PUSCH.

[0685] For example, the terminal may select one of the legacy DMRS type and the enhanced DMRS type according to the port number in each entry of the table indicated by the antenna port field. In the case of type 1, if 0 to 7 as the port number indicated by the legacy DMRS type is indicated in the antenna port field, the DMRS type may be considered to be the legacy DMRS type 1, and if port numbers 8 to 15 are indicated, the DMRS type may be considered to be the enhanced DMRS type 1. In the case of type 2, if 0 to 11 as the port number indicated by the legacy DMRS type is indicated in the antenna port field, the DMRS type may be considered to be the legacy DMRS type 2, and if port numbers 12 to 23 are indicated, the DMRS type may be considered to be the enhanced DMRS type 2.

[0686] As another example, the terminal may desire to add an indication for a conventional DMRS type or an enhanced DMRS type in each entry of the table indicated by the antenna port field. That is, a new column is added to the table used in the antenna port field indication so that a specific entry can be indicated to distinguish between the conventional DMRS type and the enhanced DMRS type.

[0687] As another example, if a method of using the same RE position by a conventional DMRS type and an enhanced DMRS type is considered (e.g., enhanced DMRS type 1 based on [enhanced DMRS type 1 supports method 4] or [enhanced DMRS type 1 supports method 5], or enhanced DMRS type 2 based on [enhanced DMRS type 2 supports method 3], as described above), the terminal can additionally indicate information about the OCC length to be applied by the terminal through each entry of the table indicated by the antenna port field. For example, one of OCC lengths 2, 3, and 6 can be indicated to distinguish between conventional DMRS type 1 and enhanced DMRS type 1, and one of OCC lengths 2 and 4 can be indicated to distinguish between conventional DMRS type 2 and enhanced DMRS type 2. That is, a new column is added to the table used in the antenna port field indication, and the OCC length value can be indicated by the information of the column.

[0688] [Method 3-3] Scheme based on the MSB or LSB of the antenna port field in the DCI

[0689] The terminal can support dynamic switching between the traditional DMRS type and the enhanced DMRS type according to the additional MSB or LSB value of the antenna port field in the DCI that schedules the PDSCH or PUSCH. For example, if the additional MSB or LSB value of the antenna port field in the DCI is 0, the terminal can consider that the traditional DMRS type has been applied to its PUSCH or PDSCH scheduling, and if the value is 1, the terminal can consider that the enhanced DMRS type is applied to its PUSCH or PDSCH scheduling (or, the opposite example is possible). The distinction between DMRS type 1 and DMRS type 2 is possible through the PDSCH or PUSCH mapping type that can be indicated by the time domain resource allocation field in the DCI. The additional MSB or LSB value of the antenna port field indicating one of the traditional and enhanced DMRS types can be determined according to whether specific high-level signaling is configured, and can be configured in PUSCH scheduling DCI format 0_1 ​​or 0_2 or PDSCH scheduling DCI format 1_1 or 1_2. Specific higher layer signaling capable of determining whether there is an additional MSB or LSB of the antenna port field may be defined individually for each DCI format, or may be commonly defined in a bandwidth part or a cell.

[0690] [Method 3-4] Solution based on new fields in DCI

[0691] The terminal can support dynamic switching between traditional DMRS type and enhanced DMRS type according to the value of the new field in the DCI for scheduling PDSCH or PUSCH. For example, the new field in the DCI can be one bit and can indicate whether the enhanced DMRS type is applied. For example, if the value of the new field in the DCI is 0, the terminal can consider that the traditional DMRS type has been applied to its PUSCH or PDSCH scheduling, and if the value is 1, the terminal can consider that the enhanced DMRS type has been applied to its PUSCH or PDSCH scheduling (or, the opposite example is possible). The distinction between DMRS type 1 and DMRS type 2 is possible through the PDSCH or PUSCH mapping type that can be indicated by the time domain resource allocation field in the DCI. The presence or absence of the new field in the DCI can be determined based on whether specific high-level signaling is configured, and can be configured in PUSCH scheduling DCI format 0_1 ​​or 0_2 or PDSCH scheduling DCI format 1_1 or 1_2. Specific higher layer signaling capable of determining the presence or absence of the new field may be defined individually for each DCI format, or may be defined commonly in a bandwidth part or a cell.

[0692] [Method 3-5] Solution based on DCI format

[0693] The terminal can support dynamic switching between the traditional DMRS type and the enhanced DMRS type according to the DCI format for scheduling PDSCH or PUSCH. For example, if PUSCH is scheduled to the terminal through DCI format 0_0 or 0_1, or PDSCH is scheduled through DCI format 1_0 or 1_1, the terminal can consider the traditional DMRS type 1 or the traditional DMRS type 2 to send or receive PUSCH or PDSCH scheduling. For example, if PUSCH is scheduled to the terminal through DCI format 0_2 or a new PUSCH scheduling DCI format (e.g., 0_3), or PDSCH is scheduled through DCI format 1_2 or a new PDSCH scheduling DCI format (e.g., 1_3), the terminal can consider enhanced DMRS type 1 or enhanced DMRS type 2 to send or receive PUSCH or PDSCH scheduling. The distinction between DMRS type 1 and DMRS type 2 is possible through the PDSCH or PUSCH mapping type that can be indicated by the time domain resource allocation field in the DCI.

[0694] [Method 3-6] MAC-CE based solution

[0695] The high-layer signaling for the traditional DMRS type 1 and the DMRS type 2 may be configured by the base station for the terminal, and the terminal may perform dynamic switching between the two DMRS types through the TDRA field in the DCI, and the dynamic switching between the traditional DMRS type and the enhanced DMRS type may be indicated to the terminal through the MAC-CE that may be received from the base station. That is, the activation and deactivation of the enhanced DMRS type may be indicated to the terminal through the MAC-CE that may be received from the base station. If only DMRS type 1 is configured for the terminal through high-layer signaling, and the terminal has received a MAC-CE indicating activation of the enhanced DMRS type, the terminal may consider that enhanced DMRS type 1 is applied to PDSCH and PUSCH scheduling after a specific time (e.g., three time slots) has passed since the transmission of the PUCCH including the HARQ-ACK information for the PDSCH including the MAC-CE. If only DMRS type 2 is configured for the terminal through high-layer signaling, and the terminal has received a MAC-CE indicating the activation of the enhanced DMRS type, the terminal may consider that enhanced DMRS type 2 is applied to PDSCH and PUSCH scheduling after a specific time (e.g., three time slots) has passed from the transmission of the PUCCH including HARQ-ACK information for the PDSCH including the MAC-CE. If DMRS type 1 and DMRS type 2 are configured for the terminal through high-layer signaling, and the terminal has received a MAC-CE indicating the activation of the enhanced DMRS type, the terminal may consider that enhanced DMRS type 1 or enhanced DMRS type 2 is applied to PDSCH and PUSCH scheduling after a specific time (e.g., three time slots) has passed from the transmission of the PUCCH including HARQ-ACK information for the PDSCH including the MAC-CE. The distinction between DMRS type 1 and DMRS type 2 is possible through the PDSCH or PUSCH mapping type that can be indicated by the time domain resource allocation field in the DCI.

[0696] [Method 3-7] Solution based on new RNTI

[0697] The terminal can consider whether the PDSCH or PUSCH scheduling is a PDSCH or PUSCH scheduling to which a conventional DMRS type is applied or a PDSCH or PUSCH scheduling to which an enhanced DMRS type is applied based on the RNTI with which the CRC of the PDCCH sent from the base station is scrambled. For example, if the terminal has successfully decoded a PDCCH with a CRC scrambled with the same RNTI as the newly defined DMRS-RNTI, the terminal can consider that the enhanced DMRS type has been applied to the PDSCH or PUSCH scheduled by the PDCCH. In contrast, if the terminal has successfully decoded a DCI with a CRC scrambled with a conventional RNTI (e.g., C-RNTI or MCS-C-RNTI) instead of the newly defined DMRS-RNTI, the terminal can consider that the scheduling is a PDSCH or PUSCH scheduling to which a conventional DMRS type has been applied. If a new RNTI is defined, the number of RNTIs that the terminal must consider increases when decoding a DCI format in a specific search space, and thus PDCCH decoding performance may be affected. Distinction between DMRS Type 1 and DMRS Type 2 is possible through the PDSCH or PUSCH mapping type which may be indicated through the time domain resource allocation field in DCI.

[0698] [Method 3-8] Scheme based on PDCCH-related information

[0699] The terminal may assume a DMRS type based on the PDCCH-related information sent from the base station, and perform PDSCH or PUSCH transmission scheduled by the PDCCH based on the DMRS type. The PDCCH-related information that the base station and the terminal may consider may be at least one of the following:

[0700] - Control resource set indexing,

[0701] - the lowest RB index in the control resource set,

[0702] - search space index,

[0703] - PDCCH monitoring opportunities in specific time slots of the search space,

[0704] -PDCCH aggregation level and candidate index, or

[0705] -Whether the PDCCH transmission is repeated.

[0706] For example, if the base station schedules PDSCH or PUSCH transmission to the terminal by using control resource set #0, the terminal may consider the scheduling to be PDSCH or PUSCH scheduling to which the conventional DMRS type has been applied. In contrast, if the base station schedules PDSCH or PUSCH transmission to the terminal by using a control resource set (e.g., control resource set #1) instead of control resource set #0, the terminal may consider the scheduling to be PDSCH or PUSCH scheduling to which the enhanced DMRS type has been applied.

[0707] As another example, if the lowest RB index of the control resource set including the PDCCH received by the terminal is an even number (or odd number), the terminal may consider the scheduling to be a PDSCH or PUSCH scheduling to which the conventional DMRS type has been applied. In contrast, if the lowest RB index of the control resource set including the PDCCH received by the terminal is an odd number (or even number), the terminal may consider the scheduling to be a PDSCH or PUSCH scheduling to which the enhanced DMRS type has been applied. The distinction between DMRS type 1 and DMRS type 2 is possible through the PDSCH or PUSCH mapping type that can be indicated by the time domain resource allocation field in the DCI.

[0708] [Method 3-9] Scheme based on scheduling information

[0709] Based on the PDSCH or PUSCH scheduling information of the base station, the dynamic switching between the traditional DMRS type and the enhanced DMRS type can be indicated to the terminal. If the information of the frequency domain resource allocation (FDRA) field for scheduling even (or odd) RBs is indicated as the PDSCH or PUSCH scheduling information received from the base station, the terminal can consider the scheduling to be the PDSCH or PUSCH scheduling to which the enhanced DMRS type has been applied. If the information of the frequency domain resource allocation (FDRA) field for scheduling odd (or even) RBs is indicated as the PDSCH or PUSCH scheduling information received from the base station, the terminal can consider the scheduling to be the PDSCH or PUSCH scheduling to which the traditional DMRS type has been applied. The distinction between DMRS type 1 and DMRS type 2 is possible through the PDSCH or PUSCH mapping type that can be indicated by the time domain resource allocation field in the DCI.

[0710] The method obtained by combining the above [method 3-1] to [method 3-9] is possible. In addition, the terminal can report the terminal capabilities for each of the above [method 3-1] to [method 3-9] to the base station, and a specific method among the above [method 3-1] to [method 3-9] can be configured and supported by high-level signaling, and it can be pre-defined in the standard with the base station.

[0711] Fig.21 A diagram illustrating the operation of a base station according to an embodiment of the present disclosure.

[0712] Fig.21 The operation of the base station can be performed based on the embodiments of the disclosure described in this article. Fig.21 The order of the operation steps in the embodiment may be changed, some steps may be omitted according to the situation, or two or more steps may be combined and performed.

[0713] The base station may receive terminal capability information from the terminal (operation 2100).

[0714] For example, the terminal capability information may include information about the terminal capability associated with the enhanced DMRS type (e.g., information about the number of enhanced DMRS types / supportable DMRS types that the terminal can support). For example, the terminal capability information may include information associated with the number of DMRS types supported by the terminal. The information associated with the number of DMRS types may include a value obtained by subtracting 1 from the number of DMRS types supported by the terminal.

[0715] Based on the received terminal capability information, the base station may send available high-layer signaling (e.g., RRC signaling) to the terminal (operation 2105). The terminal capability information and the high-layer signaling corresponding thereto may include at least one of [Enhanced DMRS Type 1 Support Method 1] to [Enhanced DMRS Type 1 Support Method 5] or [Enhanced DMRS Type 2 Support Method 1] to [Enhanced DMRS Type 2 Support Method 3] mentioned herein, may include at least one of [Method 2-1] to [Method 2-3] mentioned herein, and / or may include at least one of [Method 3-1] to [Method 3-9] mentioned herein, or may include a method obtained by combining two or more of [Method 3-1] to [Method 3].

[0716] For example, the base station may send information indicating at least one DMRS type to the terminal through higher layer signaling (eg, RRC signaling).

[0717] Based on the terminal capability information and the configuration of the corresponding higher layer signaling, the base station may send dynamic switching signaling to the terminal (operation 2110).

[0718] For example, the dynamic switching signaling may include information indicating dynamic switching between different DMRS types. For example, the switching between different DMRS types may be performed according to at least one of the above-mentioned [Method 3-1] to [Method 3-9].

[0719] Thereafter, the base station may transmit a PDSCH to which the dynamically switched DMRS type has been applied to the terminal (operation 2115 ), or receive a PUSCH to which the dynamically switched DMRS type has been applied from the terminal (operation 2115 ).

[0720] Fig. 22 A schematic diagram showing the operation of a terminal according to an embodiment of the present disclosure.

[0721] Fig. 22 The operation of the terminal can be performed based on the disclosed embodiments described in this article. Fig. 22 The order of the operation steps in the embodiment may be changed, some steps may be omitted according to the situation, or two or more steps may be combined and performed.

[0722] The terminal may transmit terminal capability information to the base station (operation 2200).

[0723] For example, the terminal capability information may include information about the terminal capability associated with the enhanced DMRS type (e.g., information about the number of enhanced DMRS types / supportable DMRS types that the terminal can support). For example, the terminal capability information may include information associated with the number of DMRS types supported by the terminal. The information associated with the number of DMRS types may include a value obtained by subtracting 1 from the number of DMRS types supported by the terminal.

[0724] The terminal may receive available high-layer signaling (e.g., RRC signaling) from the base station to correspond to the transmitted terminal capability information (operation 2205). The terminal capability information and the high-layer signaling corresponding thereto may include at least one of [Enhanced DMRS Type 1 Support Method 1] to [Enhanced DMRS Type 1 Support Method 5] or [Enhanced DMRS Type 2 Support Method 1] to [Enhanced DMRS Type 2 Support Method 3] mentioned herein, may include at least one of [Method 2-1] to [Method 2-3] mentioned herein, and / or may include at least one of [Method 3-1] to [Method 3-9] mentioned herein, or may include a method obtained by combining two or more of [Method 3-1] to [Method 3].

[0725] For example, the terminal may receive information indicating at least one DMRS type to the terminal through higher layer signaling (eg, RRC signaling).

[0726] Based on the terminal capability information and the configuration of the higher layer signaling corresponding thereto, the terminal may receive dynamic switching signaling from the base station (operation 2210).

[0727] For example, the dynamic switching signaling may include information indicating dynamic switching between different DMRS types. For example, the switching between different DMRS types may be performed according to at least one of the above-mentioned [Method 3-1] to [Method 3-9].

[0728] Thereafter, the terminal may receive a PDSCH to which the dynamically switched DMRS type has been applied from the base station (operation 2215) or transmit a PUSCH to which the dynamically switched DMRS type has been applied to the base station (operation 2215).

[0729] In addition, for example, the above Fig.21 and Fig. 22 The base station / terminal operation can be described later. Fig.23 The terminal and Fig.24 The base station is executed.

[0730] In one embodiment, conditions of a base station and a terminal for dynamic switching of DMRS types are disclosed. This embodiment can be operated by combining with the above embodiments.

[0731] By using the enhanced DMRS type 1 and the enhanced DMRS type 2 described above, the terminal can support rank 1 to a maximum rank 8 of the PDSCH and the PUSCH through single-user MIMO operation.

[0732] By using the enhanced DMRS type 1 and enhanced DMRS type 2 described above, the terminal can receive a PDSCH configured by rank 1 to a maximum of rank 8, that is, configured by one to eight layers. Similarly, the terminal can transmit a PUSCH configured by rank 1 to a maximum of rank 8.

[0733] In the case of PDSCH reception, the terminal can support up to rank 8, that is, can receive PDSCH configured by one to eight layers by using the conventional DMRS type 1 or DMRS type 2. Therefore, if the terminal supports the reception of PDSCH configured by up to eight layers by using enhanced DMRS type 1 and enhanced DMRS type 2, the terminal can notify the base station of the support through a separate selective report of the terminal capability.

[0734] The terminal capability indicating that support for enhanced DMRS type 1 and enhanced DMRS type 2 that can be used in PDSCH reception and PUSCH transmission is possible may be defined by the following two methods.

[0735] [Method 4-1-1] Define a terminal capability

[0736] In one method, a terminal and a base station may define a terminal capability report for supporting enhanced DMRS type 1 or enhanced DMRS type 2, and different information may be indicated and shared through different components in corresponding signaling. If a terminal reports a terminal capability, one or more specific functions may be basically supported, and these functions may be indicated by a random component explicitly included in a terminal capability report, or when a terminal capability report is sent from the terminal to the base station, the transmission may implicitly mean that the basic functions are supported.

[0737] [Method 4-1-2] Define multiple terminal capabilities

[0738] As another method, the terminal and the base station may define a plurality of different terminal capabilities for supporting enhanced DMRS type 1 or enhanced DMRS type 2, and one of the terminal capabilities may be defined as a basic terminal capability. The terminal may inform the base station that support for basic functions of enhanced DMRS type 1 or enhanced DMRS type 2 is possible by reporting the basic terminal capabilities. Under the premise of reporting the basic terminal capabilities, the terminal may indicate to the base station and share with the base station that support for additional functions of enhanced DMRS type 1 or enhanced DMRS type 2 is possible. The basic terminal capabilities include one or more specific functions, and these functions may be basically supported, and these functions may be represented by random components explicitly included in the basic terminal capability report, or when the basic terminal capability report is sent from the terminal to the base station, the transmission may implicitly mean support for the basic functions.

[0739] Regarding the above two methods, the terminal may distinctively define basic functions and additional (optional) functions for supporting enhanced DMRS type 1 or enhanced DMRS type 2. The definable functions that may be included in the terminal capability report may consider a combination of one or more of the following items.

[0740] -[Function 1] Supported enhanced DMRS types

[0741] ■1-1. Support enhanced DMRS type 1

[0742] ■1-2. Support enhanced DMRS type 2

[0743] ■1-3. Supporting both enhanced DMRS type 1 and enhanced DMRS type 2

[0744] -[Function 2] Number of supported layers

[0745] ■2-1. Support 1 to N layers (for example, N is a natural number from 1 to 8)

[0746] ■2-2. Support (N+1) layers to 8 layers (for example, N is a natural number from 0 to 7)

[0747] ■2-3. Support 1 to 8 layers

[0748] -[Function 3] DMRS symbol related functions: the number of DMRS symbols loaded in the front part, and the number of additional DMRS symbols

[0749] ■3-1. Reuse of terminal capability report that is already used when DMRS Type 1 and DMRS Type 2 are supported

[0750] ■3-2. Independently redefine the terminal capability report that has been used when DMRS Type 1 and DMRS Type 2 are supported

[0751] Other additional features are not excluded.

[0752] Some or all functions may be defined as basic functions, and the remaining functions other than the defined basic functions may be defined as additional functions. These functions may be functions commonly applied to PDSCH reception and PUSCH transmission, and may be functions divided and applied to each of PDSCH reception and PUSCH transmission.

[0753] For example, function 1-1 of [Function 1] above, function 2-1 (e.g., N=4) of [Function 2] above, and function 3-1 of [Function 3] above may be supported as basic functions commonly used for PDSCH reception and PUSCH transmission, and the remaining functions except the defined basic functions may be defined as additional functions. That is, the meaning of the terminal sending a basic terminal capability report to the base station may mean that the terminal supports only enhanced DMRS type 1 among enhanced DMRS type 1 and enhanced DMRS type 2, supports PDSCH reception and PUSCH transmission from rank 1 to rank 4 by using enhanced DMRS type 1, and supports the number of front-loaded DMRS symbols and the number of additional DMRS symbols through the terminal capability report that has been used when legacy DMRS type 1 and legacy DMRS type 2 are supported.

[0754] Specifically, in the case of [Function 2] above, the presence or absence of the scheme for dynamic switching between DMRS types mentioned in the above embodiment can be determined according to the maximum rank value that can be supported by the basic terminal capability defined. There may be two main reasons for the need to dynamically switch between DMRS types. The first is because enhanced DMRS type 1 and enhanced DMRS type 2 are functions added to support multi-user MIMO, and therefore may not be suitable for supporting single-user MIMO PDSCH and PUSCH with high rank values. In this case, dynamic switching between DMRS types may be required. For example, in the case where a base station schedules a specific terminal, when the base station changes from multi-user MIMO with a small number of layers to supporting single-user MIMO with a large number of layers, dynamic switching between enhanced DMRS types and traditional DMRS types can be used. Another reason is that since longer FD-OCC is used for enhanced DMRS type 1 and enhanced DMRS type 2 compared to traditional DMRS type 1 and traditional DMRS type 2, the channel estimation performance in a channel with a large delay spread may be relatively deteriorated. Therefore, in order to compensate for this deterioration, the base station can perform scheduling by dynamic switching between DMRS types to improve the performance of the terminal in PDSCH reception or PUSCH transmission. [Function 2] above may be associated with the first reason why dynamic switching between DMRS types is required.

[0755] As described in the above embodiments, the terminal may define the terminal capability for dynamic switching between DMRS types and report it to the base station.

[0756] If the terminal supports PDSCH reception or PUSCH transmission of up to rank 8 associated with [Function 2] as a basic terminal capability, that is, if all terminals supporting enhanced DMRS types have a non-standard implementation method that enables compensation related to the appropriate channel estimation performance required to support up to 8 layers in a single-user MIMO transmission or reception scheme, the terminal is able to support up to rank 8 for PDSCH reception and PUSCH transmission with low DMRS overhead by using enhanced DMRS type 1 and enhanced DMRS type 2, that is, two codewords are available. Therefore, the dynamic switching between DMRS types mentioned in the above embodiment may not be required. In this case, the base station cannot configure the terminal with one of the traditional DMRS type and enhanced DMRS type for PDSCH reception or PUSCH transmission through high-level signaling, and the terminal can support any value from rank 1 to 8 by using the DMRS type configured by the base station through high-level signaling. That is, the terminal can support a semi-static switching scheme instead of the above-mentioned scheme of dynamic switching between DMRS types. In this case, the terminal may not report the terminal capability for dynamic switching between DMRS types to the base station. In contrast, even if the terminal is able to support a maximum rank of 8 by using an enhanced DMRS type as a basic terminal capability, the terminal can report the terminal capability for dynamic switching between DMRS types to the base station for the possibility of flexible scheduling by the base station, and when receiving scheduling of a PDSCH or PUSCH configured with two codewords from the base station, the terminal can receive a PDSCH configured with two codewords of rank 5 or greater, or send a PUSCH by using a conventional DMRS type or an enhanced DMRS type in a scheme of dynamic switching between DMRS types.

[0757] If, for N of 4 or less, the terminal supports PDSCH reception or PUSCH transmission of up to rank N as a basic terminal capability in [Function 2], that is, if the terminal supporting the enhanced DMRS type does not consider the implementation of supporting a maximum of 8 layers in a single-user MIMO transmission or reception scheme, and some terminals have a non-standard implementation method that enables compensation related to the appropriate channel estimation performance required by them, then by using the enhanced DMRS type, the terminal may be able to perform only PDSCH reception or PUSCH transmission configured by N layers. When the terminal is to support a higher rank, the terminal may use a different DMRS type, or report additional (optional) terminal capabilities to the base station to indicate that support for ranks greater than N is possible even with the enhanced DMRS type. For example, if the terminal does not report support for rank 5 or higher of the enhanced DMRS type to the base station by using additional terminal capabilities, the terminal may report terminal capabilities for dynamic switching between DMRS types to the base station. In this case, if the terminal receives scheduling of a PDSCH or PUSCH configured by two codewords from a base station, the terminal may receive a PDSCH configured by two codewords with a rank of 5 or greater, or send a PUSCH by using a conventional DMRS type in a scheme of dynamic switching between DMRS types. As another example, if the terminal has reported support for rank 5 or higher of an enhanced DMRS type to the base station by using additional terminal capabilities, the terminal may not report terminal capabilities for dynamic switching between DMRS types to the base station. In this case, if the terminal receives scheduling of a PDSCH or PUSCH configured by two codewords from a base station, the terminal may support a semi-static switching scheme instead of the above-mentioned scheme of dynamic switching between DMRS types. Alternatively, even if the terminal has reported support for rank 5 or higher of an enhanced DMRS type to the base station by using additional terminal capabilities, the terminal may report terminal capabilities for dynamic switching between DMRS types to the base station. In this case, if the terminal receives scheduling of PDSCH or PUSCH configured by two codewords from the base station, the terminal can receive PDSCH configured by two codewords with rank 5 or greater, or transmit PUSCH by using a legacy DMRS type in a scheme of dynamic switching between DMRS types.

[0758] Fig.23 The structure of a UE in a wireless communication system according to an embodiment of the present disclosure is shown.

[0759] refer to Fig.23, the UE may include a transceiver including a UE receiver 2300 and a UE transmitter 2310, a memory, and a UE processor 2305 (or a UE controller or processor). The transceiver is composed of a receiver 2300 and a UE transmitter 2310. The memory and the UE processor 2305 may operate according to the above-mentioned communication method of the UE. However, the elements of the UE are not limited to the above examples. For example, the UE may include more or fewer elements than the above elements. In addition, the transmitter 2310, the memory, and the processor 2305 may be implemented in the form of a single chip.

[0760] The transceiver can send and receive signals to and from the BS. The signal may include control information and data. To this end, the transceiver may include a radio frequency (RF) transmitter for up-converting and amplifying the frequency of the transmitted signal and an RF receiver for low-noise amplification of the received signal and down-converting the frequency. However, this is only an example of a transceiver, and the elements of the transceiver are not limited to the RF transmitter and the RF receiver.

[0761] The transceiver may receive a signal through a radio channel, output the signal to the processor, and transmit a signal output from the processor through the radio channel.

[0762] The memory may store programs and data required for the operation of the UE. In addition, the memory may store control information or data included in the signals sent and received by the UE. The memory may be configured by a storage medium such as a read-only memory (ROM), a random access memory (RAM), a hard disk, a compact disk (CD)-ROM, and a digital versatile disk (DVD), or a combination of storage media. The number of memories may be plural.

[0763] The processor 2305 may control a series of processes to allow the UE to operate according to the above-described embodiments. For example, the processor 2305 may control the elements of the UE to receive DCI including two layers and simultaneously receive multiple PDSCHs. The number of processors 2305 may be plural, and the processor 2305 may perform operations to control the elements of the UE by executing a program stored in a memory.

[0764] Fig.24 The structure of a BS in a wireless communication system according to an embodiment of the present disclosure is shown.

[0765] refer to Fig.24, the BS may include a transceiver including a BS receiver 2400 and a BS transmitter 2410, a memory, and a BS processor 2405 (or a BS controller or processor). The transceiver may include a receiver 2400 and a transmitter 2410 of the BS, and the memory and the BS processor 2405 may operate according to the communication method of the BS. However, the elements of the BS are not limited to the above examples. For example, the BS may include more or fewer elements than the above elements. In addition, the transceiver 2410, the memory, and the processor 2405 may be implemented in the form of a single chip.

[0766] The transceiver 2410 may send and receive signals to and from the UE. The signals may include control information and data. To this end, the transceiver 2410 may include an RF transmitter for up-converting and amplifying the frequency of the transmitted signal and an RF receiver for low-noise amplifying the received signal and down-converting the frequency. However, this is merely an example of the transmitter 2410, and the elements of the transceiver are not limited to the RF transmitter and the RF receiver.

[0767] The transceiver may receive a signal through a radio channel, output the signal to the processor 2405, and transmit a signal output from the processor through the radio channel.

[0768] The memory may store programs and data required for the operation of the BS. The memory may store control information or data included in a signal sent and received by the BS. The memory may be configured by a storage medium such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD, or a combination of storage media. The number of memories may be plural.

[0769] The processor 2405 may control a series of processes to allow the BS to operate according to an embodiment of the present disclosure. For example, the processor may control each element of the base station to configure and transmit two types of layer DCIs, which include allocation information about multiple PDSCHs. The number of processors 2405 may be plural, and the processor 2405 may perform operations to control the elements of the BS by executing a program stored in a memory.

[0770] According to an embodiment of the present disclosure, an apparatus and method for efficiently providing a service in a wireless communication system are provided.

[0771] In addition, according to an embodiment of the present disclosure, data may be transmitted and received by applying an enhanced DMRS type.

[0772] Furthermore, according to an embodiment of the present disclosure, switching between an existing DMRS type and an enhanced DMRS type may be performed.

[0773] Effects that can be obtained in the present disclosure are not limited to the above-mentioned effects, and other unmentioned effects will be clearly understood by a person of ordinary skill in the art to which the present disclosure pertains.

[0774] The methods according to various embodiments described in the claims or specification of the present disclosure may be implemented by hardware, software, or a combination of hardware and software.

[0775] When these methods are implemented by software, a computer-readable storage medium for storing one or more programs (software modules) may be provided. One or more programs stored in the computer-readable storage medium may be configured to be executed by one or more processors in an electronic device. At least one program may include instructions that cause the electronic device to perform the methods according to the various embodiments of the present disclosure defined by the attached claims and / or disclosed herein.

[0776] The program (software module or software) may be stored in a non-volatile memory, including RAM and flash memory, ROM, electrically erasable programmable read-only memory (EEPROM), magnetic disk storage devices, CD-ROM, DVD, other types of optical storage devices, or cassette tapes. Alternatively, any combination of some or all of the storage devices may form the memory in which the program is stored. In addition, multiple such memories may be included in the electronic device.

[0777] In addition, the program can be stored in an attachable storage device that can access the electronic device through a communication network, such as the Internet, an intranet, a local area network (LAN), a wide area network (WLAN), and a storage area network (SAN) or a combination thereof. Such a storage device can access the electronic device via an external port. In addition, an independent storage device on a communication network can access a portable electronic device.

[0778] In the above detailed embodiments of the present disclosure, the elements included in the present disclosure are expressed in the singular or plural, depending on the detailed embodiments presented. However, for the convenience of description, the singular form or the plural form is appropriately selected as the presented situation, and the present disclosure is not limited to the elements expressed in the singular or plural. Therefore, the elements expressed in the plural may also include a single element, or the elements expressed in the singular may also include multiple elements.

[0779] The embodiments of the present disclosure described and shown in the specification and the drawings have been presented to easily explain the technical content of the present disclosure and to help understand the present disclosure, and are not intended to limit the scope of the present disclosure. That is, it is obvious to those skilled in the art that other modifications and changes can be made to it based on the technical ideas of the present disclosure. In addition, as needed, the above-mentioned various embodiments can be implemented in combination. For example, an embodiment of the present disclosure can be partially combined with other embodiments to operate a BS and a terminal. As an example, the embodiments of the present disclosure described herein can be combined with each other to operate a BS and a terminal. In addition, although the above-mentioned 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, 5G or NR systems.

[0780] In the drawings describing the methods of the present disclosure, the order of description does not always correspond to the order in which the steps of each method are performed, and the order or relationship between the steps may be changed, or the steps may be performed in parallel.

[0781] Alternatively, in the drawings describing the method of the present disclosure, some elements may be omitted, and only some elements may be included therein without departing from the basic spirit and scope of the present disclosure.

[0782] Furthermore, in the method of the present disclosure, some or all of the contents of each embodiment may be combined without departing from the basic spirit and scope of the present disclosure.

[0783] Various embodiments of the present disclosure have been described. The above description of the present disclosure is for illustration, and the embodiments of the present disclosure are not limited to the disclosed embodiments. Those skilled in the art will appreciate that the present disclosure can be easily modified into other detailed forms without changing the technical ideas or its basic features. The scope of the present disclosure is represented by the claims to be described below rather than the detailed description, and it should be understood that the meaning and scope of the claims and all changes or modified forms derived from their equivalents fall within the scope of the present disclosure.

[0784] While the present disclosure has been particularly shown and described with reference to certain embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made without departing from the spirit and scope of the present disclosure as defined by the appended claims and their equivalents.

[0785] Although the present disclosure has been described with various embodiments, various changes and modifications may occur to those skilled in the art. The present disclosure is intended to encompass such changes and modifications as fall within the scope of the appended claims.

Claims

1. A method performed by a terminal in a wireless communication system, the method include: receiving first information indicating at least one demodulation reference signal (DMRS) type from a base station via radio resource control (RRC) signaling; receiving second information indicating whether to activate an enhanced DMRS type corresponding to the at least one DMRS type from a base station via medium access control-control element (MAC-CE) signaling; as well as In case the second information indicates activation of the enhanced DMRS type, a physical downlink shared channel (PDSCH) is received from the base station or a physical uplink shared channel (PUSCH) is transmitted to the base station based on the enhanced DMRS type.

2. The method according to claim 1, in: The at least one DMRS type includes DMRS type 1 or DMRS type 2, In case the first information indicates DMRS type 1 and the second information indicates activation of an enhanced DMRS type, a DMRS of a PDSCH or a DMRS of a PUSCH is based on enhanced DMRS type 1, and In case the first information indicates DMRS type 2 and the second information indicates activation of an enhanced DMRS type, the DMRS of the PDSCH or the DMRS of the PUSCH is based on enhanced DMRS type 2.

3. The method according to claim 1, in, The length of the orthogonal cover code (OCC) associated with the enhanced DMRS type is 4 or 6.

4. The method according to claim 1, further comprising: include: In a case where the second information does not indicate activation of the enhanced DMRS type, a PDSCH is received from the base station or a PUSCH is sent to the base station based on the at least one DMRS type. 5 . The method of claim 1 , further comprising transmitting capability information to the base station, the capability information comprising information associated with the number of DMRS types supported by the terminal.

6. The method according to claim 5, in: The information associated with the number of DMRS types supported by the terminal includes a value obtained by subtracting 1 from the number of DMRS types supported by the terminal, and The DMRS types supported by the terminal include at least DMRS type 1.

7. A method performed by a base station in a wireless communication system, the method include: sending first information indicating at least one demodulation reference signal (DMRS) type to a terminal via radio resource control (RRC) signaling; sending, via medium access control-control element (MAC-CE) signaling, to the terminal second information indicating whether to activate an enhanced DMRS type corresponding to the at least one DMRS type; as well as In case the second information indicates activation of the enhanced DMRS type, a physical downlink shared channel (PDSCH) is transmitted to the terminal or a physical uplink shared channel (PUSCH) is received from the terminal based on the enhanced DMRS type.

8. The method according to claim 7, in: The length of the orthogonal cover code (OCC) associated with the enhanced DMRS type is 4 or 6, The at least one DMRS type includes DMRS type 1 or DMRS type 2, In case the first information indicates DMRS type 1 and the second information indicates activation of an enhanced DMRS type, a DMRS of a PDSCH or a DMRS of a PUSCH is based on enhanced DMRS type 1, and In case the first information indicates DMRS type 2 and the second information indicates activation of an enhanced DMRS type, the DMRS of the PDSCH or the DMRS of the PUSCH is based on enhanced DMRS type 2.

9. The method according to claim 7, further comprising: include: In a case where the second information does not indicate activation of the enhanced DMRS type, a PDSCH is transmitted to the terminal or a PUSCH is received from the terminal based on the at least one DMRS type.

10. The method according to claim 7, further comprising receiving capability information from the terminal, the capability information comprising information associated with the number of DMRS types supported by the terminal, in: The information associated with the number of DMRS types supported by the terminal includes a value obtained by subtracting 1 from the number of DMRS types supported by the terminal, and The DMRS types supported by the terminal include at least DMRS type 1.

11. A terminal in a wireless communication system, the terminal include: Transceiver; and A processor is coupled to the transceiver and is configured to: receiving first information indicating at least one demodulation reference signal (DMRS) type from a base station via radio resource control (RRC) signaling, receiving second information indicating whether to activate an enhanced DMRS type corresponding to the at least one DMRS type from a base station via medium access control-control element (MAC-CE) signaling, and In case the second information indicates activation of the enhanced DMRS type, a physical downlink shared channel (PDSCH) is received from the base station or a physical uplink shared channel (PUSCH) is transmitted to the base station based on the enhanced DMRS type.

12. The terminal according to claim 11, in: The at least one DMRS type includes DMRS type 1 or DMRS type 2, In case the first information indicates DMRS type 1 and the second information indicates activation of an enhanced DMRS type, a DMRS of a PDSCH or a DMRS of a PUSCH is based on enhanced DMRS type 1, and In case the first information indicates DMRS type 2 and the second information indicates activation of an enhanced DMRS type, the DMRS of the PDSCH or the DMRS of the PUSCH is based on enhanced DMRS type 2.

13. The terminal according to claim 11, in, The processor is also configured to: sending capability information to a base station, the capability information comprising information associated with the number of DMRS types supported by the terminal, wherein the information associated with the number of DMRS types supported by the terminal includes a value obtained by subtracting 1 from the number of DMRS types supported by the terminal, and The DMRS types supported by the terminal include at least DMRS type 1.

14. A base station in a wireless communication system, the base station include: Transceiver; and A processor is coupled to the transceiver and is configured to: sending first information indicating at least one demodulation reference signal (DMRS) type to a terminal via radio resource control (RRC) signaling, sending second information indicating whether to activate an enhanced DMRS type corresponding to the at least one DMRS type to the terminal via medium access control-control element (MAC-CE) signaling, and In case the second information indicates activation of the enhanced DMRS type, a physical downlink shared channel (PDSCH) is transmitted to the terminal or a physical uplink shared channel (PUSCH) is received from the terminal based on the enhanced DMRS type.

15. The base station according to claim 14, in, The processor is further configured to receive capability information from the terminal, the capability information comprising information associated with the number of DMRS types supported by the terminal, wherein: The information associated with the number of DMRS types supported by the terminal includes a value obtained by subtracting 1 from the number of DMRS types supported by the terminal, and The DMRS types supported by the terminal include at least DMRS type 1.

Images