Method and apparatus for transmission and reception of spatially multiplexed reference signal between multiple users in wireless communication system

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. The present disclosure relates to operation of a user equipment (UE) and a base station. Specifically, the present disclosure relates to a method for transmitting or receiving data or a reference signal in a wireless communication system and an apparatus for performing the same.

Description

Technical Field

[0001] The present disclosure relates to operations of a user equipment (UE) and a base station. In particular, the present disclosure relates to a method for transmitting or receiving data or a reference signal in a wireless communication system and an apparatus for performing the method. Background Art

[0002] The fifth generation (5G) mobile communication technology defines a wide frequency band to provide higher transmission rates and new services, and can be implemented in "below 6 GHz" frequency bands such as 3.5 GHz, and can also be implemented in "above 6 GHz" frequency bands called millimeter wave bands including 28 GHz and 39 GHz. In addition, it has been proposed to implement the sixth generation 6G mobile communication technology (e.g., super 5G system) in the terahertz frequency band (e.g., 95 GHz to 3 THz frequency band) in order to achieve a transmission rate fifty times faster than 5G mobile communication technology and an ultra-low latency one-tenth of 5G mobile communication technology.

[0003] Since the start of the development of 5G mobile communication technology, in order to support various services and meet performance requirements related to enhanced mobile broadband (eMBB), ultra-reliable low latency communication (URLLC), and massive machine type communication (mMTC), there has been ongoing standardization on beamforming and massive multiple-input multiple-output (MIMO) for mitigating radio wave path loss in mmWave and increasing radio wave transmission distance, support for dynamic operation of parameter sets (e.g., operating multiple subcarrier spacings (SCSs)) and slot formats for efficient utilization of mmWave resources, initial access technology for supporting multi-beam transmission and broadband, definition and operation of bandwidth part (BWP), new channel coding methods such as low-density parity-check (LDPC) codes for large-volume data transmission and polar codes for highly reliable transmission of control information, layer 2 (L2) preprocessing, and network slicing for providing dedicated networks tailored for specific services.

[0004] Currently, there are ongoing discussions on improvements and performance enhancements of initial 5G mobile communication technologies in view of the services that 5G mobile communication technologies are to support, and there has been physical layer standardization on technologies such as Vehicle-to-Everything (V2X) for assisting autonomous vehicles in making driving decisions based on information about the location and status of vehicles transmitted by the vehicles and for enhancing user convenience, New Radio (NR) Unlicensed (U) for system operation intended to comply with various regulatory-related requirements in unlicensed bands, NR UE power saving, Non-Terrestrial Networks (NTNs) as UE-satellite direct communication for providing coverage in areas where communication with terrestrial networks is not possible, and positioning.

[0005] There has also been ongoing standardization in the air interface architecture / protocol area on technologies such as the Industrial Internet of Things (IIoT) for supporting new services through interworking and convergence with other industries, Integrated Access and Backhaul (IAB) for providing nodes for network service area extension by supporting wireless backhaul links and access links in an integrated manner, mobility enhancements including conditional handover and dual active protocol stack (DAPS) handover, and two-step random access (two-step RACH for NR) for simplifying the random access procedure.

[0006] In terms of system architecture / services, standardization is also underway on the following: 5G baseline architecture (e.g., service-based architecture or service-based interface) for combining network function virtualization (NFV) and software-defined networking (SDN) technologies, and mobile edge computing (MEC) for receiving services based on UE location.

[0007] As 5G mobile communication systems are commercialized, an exponentially growing number of connected devices will be connected to the communication network, and it is expected that enhanced functions and performance of 5G mobile communication systems and integrated operations of connected devices will be necessary. To this end, new studies are scheduled on extended reality (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.

[0008] Such development of 5G mobile communication systems will serve as the basis for the development of new waveforms for providing coverage in the terahertz band of 6G mobile communication technology, multi-antenna transmission technologies 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 technologies using orbital angular momentum (OAM), and reconfigurable smart surfaces (RIS), as well as the development of full-duplex technologies for improving frequency efficiency and improving system networks in 6G mobile communication technology, AI-based communication technologies for achieving system optimization by leveraging satellites and AI from the design stage and internalizing end-to-end AI support functions, and next-generation distributed computing technologies for realizing services with a complexity level that exceeds the limits of UE operating capabilities by utilizing ultra-high performance communication and computing resources.

[0009] The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with respect to the present disclosure. Summary of the invention

[0010] Technical issues

[0011] Various embodiments disclosed herein provide a method and apparatus for efficiently providing services in a mobile communication system.

[0012] Aspects of the present disclosure are aimed at addressing at least the above-mentioned problems.

[0013] The present disclosure is intended to address the above-mentioned problems and disadvantages, and to provide at least the advantages described below.

[0014] Solution to the problem

[0015] According to one aspect of the present disclosure, a method performed by a terminal in a communication system is provided. The method includes: receiving configuration information about an enhanced demodulation reference signal (DMRS) for a physical downlink shared channel (PDSCH) from a base station; receiving downlink control information (DCI) for scheduling the PDSCH from the base station, the DCI including antenna port information associated with the enhanced DMRS; and receiving downlink data and enhanced DMRS from the base station on the PDSCH based on the DCI, wherein, in the case where the enhanced DMRS corresponds to enhanced DMRS type 1, the enhanced DMRS can support up to 16 antenna ports based on a frequency domain (FD)-orthogonal cover code (orthogonal cover code, OCC) of length 4, and wherein, in the case where the enhanced DMRS corresponds to enhanced DMRS type 2, the enhanced DMRS can support up to 24 antenna ports based on a FD-OCC of length 4.

[0016] According to another aspect of the present disclosure, a method performed by a base station in a communication system is provided, the method comprising: sending configuration information about an enhanced demodulation reference signal (DMRS) for a physical downlink shared channel (PDSCH) to a terminal; sending downlink control information (DCI) for scheduling the PDSCH to the terminal, the DCI including antenna port information associated with the enhanced DMRS; and sending downlink data and the enhanced DMRS to the terminal on the PDSCH, wherein, in a case where the enhanced DMRS corresponds to an enhanced DMRS type 1, the enhanced DMRS is capable of supporting up to 16 antenna ports based on a frequency domain (FD)-orthogonal cover code (OCC) of length 4, and wherein, in a case where the enhanced DMRS corresponds to an enhanced DMRS type 2, the enhanced DMRS is capable of supporting up to 24 antenna ports based on a FD-OCC of length 4.

[0017] According to another aspect of the present disclosure, a terminal in a communication system is provided. The terminal includes a transceiver and a controller, the controller is coupled to the transceiver and is configured to receive configuration information about an enhanced demodulation reference signal (DMRS) for a physical downlink shared channel (PDSCH) from a base station, receive downlink control information (DCI) for scheduling the PDSCH from the base station, the DCI includes antenna port information associated with the enhanced DMRS, and receive downlink data and the enhanced DMRS from the base station on the PDSCH based on the DCI, wherein, in the case where the enhanced DMRS corresponds to enhanced DMRS type 1, the enhanced DMRS can support up to 16 antenna ports based on a frequency domain (FD)-orthogonal cover code (OCC) of length 4, and wherein, in the case where the enhanced DMRS corresponds to enhanced DMRS type 2, the enhanced DMRS can support up to 24 antenna ports based on a FD-OCC of length 4.

[0018] According to another aspect of the present disclosure, a base station in a communication system is provided. The base station includes a transceiver and a controller, the controller is coupled to the transceiver and is configured to send configuration information about an enhanced demodulation reference signal (DMRS) for a physical downlink shared channel (PDSCH) to a terminal, send downlink control information (DCI) for scheduling the PDSCH to the terminal, the DCI includes antenna port information associated with the enhanced DMRS, and send downlink data and the enhanced DMRS to the terminal on the PDSCH, wherein, in the case where the enhanced DMRS corresponds to enhanced DMRS type 1, the enhanced DMRS can support up to 16 antenna ports based on a frequency domain (FD)-orthogonal cover code (OCC) of length 4, and wherein, in the case where the enhanced DMRS corresponds to enhanced DMRS type 2, the enhanced DMRS can support up to 24 antenna ports based on a FD-OCC of length 4.

[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 including but not limited to; 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, bound to or bound with, having, having the property of, etc.; and the term "controller" means any device, system, or portion thereof that controls at least one operation, such device may be 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 local or remote.

[0020] In addition, the various functions described below may 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 portion thereof, suitable for implementation in 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 disk (DVD), or any other type of memory. "Non-transitory" computer-readable media do not include wired, wireless, optical, or other communication links that transmit temporary electrical or other signals. Non-transitory computer-readable media include media in which data can be permanently stored and media in which data can be stored and later rewritten, such as rewritable optical disks or erasable memory devices.

[0021] Definitions for certain words and phrases are provided throughout 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] The disclosed embodiments provide an apparatus and method capable of effectively providing services in a mobile communication system. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The above and other aspects, features and advantages of certain embodiments of the present disclosure will become more apparent through the following description in conjunction with the accompanying drawings, in which:

[0025] Figure 1 The basic structure of the time-frequency domain in the wireless communication system according to the embodiment of the present disclosure is shown;

[0026] 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;

[0027] Figure 3 An example of bandwidth portion configuration in a wireless communication system according to an embodiment of the present disclosure is shown;

[0028] Figure 4 An example of a control region configuration of a downlink control channel in a wireless communication system according to an embodiment of the present disclosure is shown;

[0029] Figure 5 The structure of a downlink control channel in a wireless communication system according to an embodiment of the present disclosure is shown;

[0030] Figure 6 An example of base station beam allocation configured according to TCI status in a wireless communication system according to an embodiment of the present disclosure is shown;

[0031] Figure 7 An example of a TCI state allocation method in a wireless communication system according to an embodiment of the present disclosure is shown;

[0032] Figure 8 An example of a TCI indication MACCE signaling structure for a PDCCH DMRS in a wireless communication system according to an embodiment of the present disclosure is shown;

[0033] Fig. 9 The structure of beam configuration for CORESET and search space in a wireless communication system according to an embodiment of the present disclosure is shown;

[0034] Fig.10 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;

[0035] Fig.11 An example of time axis resource allocation of a PDSCH in a wireless communication system according to an embodiment of the present disclosure is shown;

[0036] Fig.12 An example of time axis resource allocation according to subcarrier spacing of a data channel and a control channel in a wireless communication system according to an embodiment of the present disclosure is shown;

[0037] Fig.13 A process for beam configuration and activation of a PDSCH according to an embodiment of the present disclosure is shown;

[0038] Fig.14 An example of a MAC-CE structure for PDSCH TCI state activation / deactivation MAC CE structure according to an embodiment of the present disclosure is shown;

[0039] Fig.15 An example of antenna port configuration and resource allocation for cooperative communication in a wireless communication system according to an embodiment of the present disclosure is shown;

[0040] Fig.16 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;

[0041] Fig.17An example of a MAC-CE structure for enhancing a PDSCH TCI state activation / deactivation MAC CE structure according to an embodiment of the present disclosure is shown;

[0042] Fig.18 The operation of a UE for activating a DMRS orthogonal cover code according to an embodiment of the present disclosure is shown;

[0043] Fig.19 The operation of a base station for deactivating a DMRS orthogonal cover code according to an embodiment of the present disclosure is shown;

[0044] Fig. 20 An example of spatial multiplexing between existing DMRS types and enhanced DMRS types according to an embodiment of the present disclosure is shown;

[0045] Fig.21 A method for controlling DMRS power when supporting enhanced DMRS according to an embodiment of the present disclosure is shown;

[0046] Fig. 22 An example of the operation of a UE for performing DMRS reception according to an embodiment of the present disclosure is shown;

[0047] Fig.23 An example of the operation of a base station for performing DMRS transmission according to an embodiment of the present disclosure is shown;

[0048] Fig.24 The structure of a UE in a wireless communication system according to an embodiment of the present disclosure is shown; and

[0049] Fig.25 The structure of a base station in a wireless communication system according to an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0050] Discussed below Figures 1 to 25 The various embodiments of the principles of the present disclosure used to describe in this patent document are illustrative 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.

[0051] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0052] When describing the embodiments, descriptions related to technical contents that are well known in the relevant field and not directly related to the present disclosure will be omitted. Such unnecessary omission of descriptions is intended to prevent the main idea of ​​the present disclosure from being obscured and to more clearly transfer the main idea.

[0053] For the same reason, 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 are provided with the same reference numerals.

[0054] 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 be 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 the present disclosure and inform those skilled in the art of the scope of the present disclosure, and the present disclosure is limited only by the scope of 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 consideration 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 terms should be based on the content in the entire specification.

[0055] In the following description, a base station is an entity that allocates resources to a terminal, and may be at least one of a gNode B, an eNode B, a Node B, a base station (BS), a wireless access unit, a base station controller, and a node on a network. The terminal may include a user equipment (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 (DL)" refers to a radio link via which a base station sends a signal to a terminal, and "uplink (UL)" refers to a radio link via which a terminal sends a signal to a base station. In addition, in the following description, an LTE or LTE-A system may be described by way of example, but the embodiments of the present disclosure may also be applied to other communication systems having similar technical backgrounds or channel types. Examples of such communication systems may include 5th generation mobile communication technologies (5G, new radio, and NR) developed beyond LTE-A, and in the following description, "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 embodiments of the present disclosure may also be applied to other communication systems with some modifications without significantly departing from the scope of the present disclosure.

[0056] In this article, 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 means for realizing the functions specified in one or more flowchart boxes. 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 act in a particular way, so that the instructions stored in the computer-available or computer-readable memory produce an article of instruction including the function specified in the flowchart box or multiple boxes. 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 performed on the computer or other programmable device to produce a computer-implemented process so that the instructions executed on the computer or other programmable device provide steps for realizing the functions specified in one or more flowchart boxes.

[0057] In addition, each box of the flowchart diagram may represent a module, fragment or portion of code, which includes one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative embodiments, the functions marked in the box may not occur in order. For example, two boxes shown in succession can actually be executed substantially simultaneously, or these boxes can sometimes be executed in reverse order, depending on the functions involved.

[0058] As used in the embodiments of the present disclosure, "unit" refers to a software element or a hardware element that performs a predetermined function, such as a field programmable gate array (FPGA) or an application-specific integrated circuit (ASIC). However, "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, program code segments, drivers, firmware, microcodes, circuits, data, databases, data structures, tables, arrays, and parameters. The elements and functions provided by the "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 one or more CPUs in a reproduction device or a secure multimedia card. In addition, according to some embodiments, a "unit" can include one or more processors.

[0059] Wireless communication systems are evolving into broadband wireless communication systems for providing high-speed and high-quality packet data services using communication standards such as High Speed ​​Packet Access (HSPA) of 3GPP, LTE {Long Term Evolution or Evolved Universal Terrestrial Radio Access (E-UTRA)}, LTE-Advanced (LTE-A), LTE-Pro, High Speed ​​Packet Data (HRPD) of 3GPP2, Ultra Mobile Broadband (UMB), IEEE 802.16 e, etc., as well as typical voice-based services.

[0060] As a typical example of a broadband wireless communication system, the LTE system adopts an orthogonal frequency division multiplexing (OFDM) scheme in the downlink (DL) and a single carrier frequency division multiple access (SC-FDMA) scheme in the uplink (UL). The uplink indicates a radio link through which a user equipment (UE) (or a mobile station (MS)) transmits data or a control signal to a base station (BS) (eNode B), and the downlink indicates a radio link through which a base station transmits data or a control signal to a UE. The above-mentioned multiple access scheme can separate the data or control information of each user by allocating and operating time-frequency resources for transmitting data or control information to each user to avoid overlapping with each other, that is, to establish orthogonality.

[0061] Since the 5G communication system, which is a post-LTE communication system, can freely reflect various requirements of users, service providers, etc., it can support services that meet various requirements. Services considered in the 5G communication system include enhanced mobile broadband (eMBB) communication, massive machine type communication (mMTC), ultra-reliable low latency communication (URLLC), etc.

[0062] eMBB is designed to provide higher data rates than those supported by existing LTE, LTE-A or LTE-Pro. For example, in a 5G communication system, eMBB can provide a peak data rate of 20Gbps in the downlink and a peak data rate of 10Gbps in the uplink for a single base station. In addition, the 5G communication system can provide an increased user-perceived data rate as well as a maximum data rate to the UE. In order to meet such requirements, it is necessary to improve the transmission / reception technology including further enhanced multiple-input multiple-output (MIMO) transmission technology. In addition, a frequency bandwidth greater than 20MHz can be used in a frequency band of 3 to 6GHz or 6GHz or higher to obtain the data rate required by the 5G communication system, instead of using a transmission bandwidth of up to 20MHz to send signals in the 2GHz frequency band used in LTE.

[0063] In addition, mMTC is being considered to support application services such as the Internet of Things (IoT) in a 5G communication system. mMTC has requirements such as supporting the connection of a large number of UEs in a cell, enhanced coverage of UEs, improved battery time, reduction in the cost of UEs, etc., in order to effectively provide the Internet of Things. Since the Internet of Things provides communication functions while providing to various sensors and various devices, it can support a large number of UEs in a cell (e.g., 1,000,000 UEs / km2). In addition, a UE supporting mMTC may require a wider coverage than the coverage of other services provided by the 5G communication system because the UE may be located in a shadow area (such as a basement of a building) that is not covered by the cell due to the nature of the service. A UE supporting mMTC may be configured to be inexpensive and may require a very long battery life, such as 10 to 15 years, because it is difficult to frequently replace the battery of the UE.

[0064] Finally, URLLC, which is a cellular-based mission-critical wireless communication service, can be used for remote control of robots or machines, industrial automation, unmanned aerial vehicles, remote healthcare, emergency alerts, etc. Therefore, URLLC can provide communications with ultra-low latency and ultra-high reliability. For example, services supporting URLLC can meet an air interface delay of less than 0.5 ms and also require a packet error rate of 10-5 or less. Therefore, for services supporting URLLC, the 5G system can provide a shorter transmission time interval (TTI) than that of other services, and may also require a design for allocating a large amount of resources in the frequency band in order to ensure the reliability of the communication link.

[0065] The three 5G services (i.e., eMBB, URLLC, and mMTC) can be multiplexed and transmitted in a single system. In this case, different transmission / reception technologies and transmission / reception parameters can be used between the services to meet the different requirements of each service. Of course, 5G is not limited to the above three services.

[0066] [NR time-frequency resources]

[0067] Hereinafter, the frame structure of the 5G system will be described in detail with reference to the accompanying drawings.

[0068] Figure 1 The basic structure of the time-frequency domain, which is the radio resource area for sending data or control channels in the 5G system, is shown.

[0069] exist Figure 1In the time-frequency domain, the horizontal axis indicates the time domain, and the vertical axis indicates the frequency domain. The basic unit of resources in the time-frequency domain is a resource element (RE) 101, and can be defined as one orthogonal frequency division multiplexing (OFDM) 102 on the time axis and one subcarrier 103 on the frequency axis. In the frequency domain, (eg, 12) consecutive REs may constitute one resource block (RB) 104 .

[0070] 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.

[0071] exist Figure 2 , an example of a structure including a frame 200, a subframe 201, and a time slot 202 is shown. One frame 200 may be defined as 10 ms. One subframe 201 may be defined as 1 ms, and correspondingly, 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 ( )=14). One subframe 201 may include one or more time slots 202 and 203, and the number of time slots 202 and 203 of each subframe 201 may vary according to the configured value μ (204 or 205) of the subcarrier spacing. Figure 2 The example shows a case where the subcarrier spacing configuration value corresponds to μ=0 (204) and a case where the subcarrier spacing configuration value corresponds to μ=1 (205). In the case of μ=0 (204), one subframe 201 may include one time slot 202, and in the case of μ=1 (205), one subframe 201 may include two time slots 203. That is, the number of time slots per subframe ( ) can vary depending on the configured value μ of the subcarrier spacing, and therefore, the number of slots per frame ( ) can also vary. According to each subcarrier spacing configuration μ and The configuration may be defined as shown in Table 1 below.

[0072]

Table 1

[0073]

[0074] [Bandwidth Part (BWP)]

[0075] A bandwidth part (BWP) configuration in a 5G communication system will be described in detail with reference to the accompanying drawings.

[0076] Figure 3 An example of bandwidth portion configuration in a wireless communication system according to an embodiment of the present disclosure is shown.

[0077] Figure 3 An example is shown in which the UE bandwidth 300 is configured into two bandwidth parts, namely, bandwidth part #1 (BWP#1) 301 and bandwidth part #2 (BWP#2) 302. The base station may configure one or more bandwidth parts to the UE, and may configure the following information for each bandwidth part.

[0078]

Table 2

[0079]

[0080] Of course, not limited to the above examples, in addition to the configuration information, various parameters about the bandwidth part can also be configured to the UE. This information can be transmitted to the UE by the base station through higher layer signaling (e.g., radio resource control (RRC)). Among one or more configured bandwidth parts, at least one bandwidth part can be activated. The information indicating whether the configured bandwidth part is activated can be semi-statically transmitted from the base station to the UE through RRC signaling, or can be dynamically transmitted through downlink control information (DCI).

[0081] According to some embodiments, the UE may receive the configuration of the initial BWP for initial access from the base station through a master information block (MIB) before RRC connection. More specifically, the UE may receive configuration information for a control region (control resource set (CORESET)) and a search space in which a PDCCH for receiving system information required for initial access through the MIB (which may correspond to the remaining system information (RMSI) or the system information block 1 (SIB1)) may be sent in the initial access step. Each of the control region and the search space configured through the MIB may be considered as an identification (ID) 0. The base station may notify the UE of configuration information such as frequency allocation information, time allocation information, parameter set, etc. for control region #0 through the MIB. In addition, the base station may notify the UE of configuration information for the monitoring period and timing of control region #0, that is, configuration information for search space #0 through the MIB. The UE may regard the frequency region configured as the control region #0 acquired from the MIB as the initial bandwidth portion for initial access. Here, the ID of the initial BWP may be considered as 0. The UE may receive a physical downlink shared channel (PDSCH) through which the SIBs are transmitted through the configured initial bandwidth portion. The initial bandwidth portion may be used not only for the reception of SIBs but also for other system information (OSI), paging, or random access.

[0082] [Bandwidth Part (BWP) Change]

[0083] In the case where one or more bandwidth parts are configured in the UE, the base station may indicate the change (or switch or transition) of the bandwidth part to the UE via the bandwidth part indicator field in the DCI. Figure 3 In the present invention, when the currently activated bandwidth part of the UE is bandwidth part #1 301, the base station can indicate bandwidth part #2 302 to the UE through the bandwidth part indicator in the DCI, and the UE can make a bandwidth part change to the bandwidth part #2 302 indicated by the received bandwidth part indicator in the DCI.

[0084] [SS / PBCH block]

[0085] Subsequently, a synchronization signal (SS) / PBCH block in 5G is described.

[0086] The SS / PBCH block may correspond to a physical layer channel block including a primary SS (PSS), a secondary SS (SSS), and a PBCH. A detailed description thereof is given below.

[0087] -PSS: A signal that serves as a reference for downlink time / frequency synchronization and provides partial information of the cell ID.

[0088] -SSS: is a reference for downlink time / frequency synchronization and provides the remaining cell ID information not provided by the PSS. In addition, the SSS can be used as a reference signal for demodulation of the PBCH.

[0089] -PBCH: Provides necessary system information necessary for UE to transmit and receive data channels and control channels. The necessary system information may include search space related control information indicating radio resource mapping information for control channels and scheduling control information of a separate data channel for transmitting system information.

[0090] -SS / PBCH block: includes a combination of PSS, SSS and PBCH. One or more SS / PBCH blocks may be transmitted within 5 ms, and each of the transmitted SS / PBCH blocks may be distinguished by an index.

[0091] The UE may detect the PSS and SSS and decode the PBCH in the initial access phase. The UE may acquire the MIB from the PBCH and receive the configuration of the control region (control resource set (CORESET)) #0 (corresponding to the control region with the control region index 0) therefrom. The UE may monitor the control region #0 based on the assumption that the demodulation reference signal (DMRS) transmitted in the control region #0 and the selected SS / PBCH block are quasi-co-located (QCLed). The UE may receive system information through the downlink control information transmitted in the control region #0. The UE may acquire configuration information related to the random access channel (RACH) required for initial access from the received system information. The UE may transmit a physical RACH (PRACH) to the base station considering the selected SS / PBCH block index, and the base station having received the PRACH may acquire the SS / PBCH block index selected by the UE. The base station may know which block the UE has selected from the SS / PBCH blocks and monitor the control region #0 associated therewith.

[0092] [PDCCH: related to DCI]

[0093] Next, downlink control information (DCI) in the 5G system will be described in detail.

[0094] In the 5G system, scheduling information about uplink data (or physical uplink shared channel (PUSCH)) or downlink data (or physical downlink shared channel (PDSCH)) is transmitted from the base station to the UE through DCI. The UE can monitor the fallback DCI format and non-fallback DCI format for PUSCH or PDSCH. The fallback DCI format can be configured with a fixed field predefined between the base station and the UE, and the non-fallback DCI format can include a configurable field.

[0095] The DCI may be subjected to a channel coding and modulation process and then transmitted through a physical downlink control channel (PDCCH). A cyclic redundancy check (CRC) may be attached to the DCI message payload, and the CRC may be scrambled by a radio network temporary identifier (RNTI) corresponding to the identity of the UE. Different types of RNTIs may be used according to the purpose of the DCI message, for example, UE-specific (UE-specific) data transmission, power control commands, random access responses, and the like. That is, the RNTI may not be explicitly transmitted and may be transmitted after being included in the CRC calculation process. If the UE has received a DCI message transmitted on the PDCCH, the UE may identify the CRC by using the allocated RNTI, and if the CRC identification result is correct, the UE may recognize that the message has been transmitted to the UE. The RNTI may change according to the use of the DCI.

[0096] DCI format 0_0 may be used for fallback DCI scheduling PUSCH, and in this case, CRC may be scrambled by C-RNTI.DCI format 0_0 with CRC scrambled by C-RNTI may include, for example, the following information.

[0097]

Table 3

[0098]

[0099] DCI format 0_1 ​​may be used for scheduling non-fallback DCI for PUSCH, and in this case, the CRC may be scrambled by the C-RNTI.DCI format 0_1 ​​with CRC scrambled by the C-RNTI may include, for example, the following information.

[0100]

Table 4

[0101]

[0102]

[0103] DCI format 1_0 may be used for fallback DCI scheduling PDSCH, and in this case, CRC may be scrambled by C-RNTI.DCI format 1_0 with CRC scrambled by C-RNTI may include, for example, the following information.

[0104]

Table 5

[0105]

[0106] DCI format 1_1 may be used for scheduling non-fallback DCI for PDSCH, and in this case, the CRC may be scrambled by the C-RNTI.DCI format 1_1 with CRC scrambled by the C-RNTI may include, for example, the following information.

[0107]

Table 6

[0108]

[0109] [PDCCH: CORESET, REG, CCE, search space]

[0110] The downlink control channel in the 5G communication system will be described in more detail below with reference to the accompanying drawings.

[0111] Figure 4 An example of a control region (control resource set (CORESET)) through which a downlink control channel is transmitted in a 5G wireless communication system is shown. Figure 4An example is shown in which a UE bandwidth part 410 is configured in the frequency axis and two control regions (control region #1 401 and control region #2 402) are configured within a time slot 420 on the time axis. The control regions 401 and 402 may be configured in specific frequency resources 403 within the entire UE bandwidth part 410 on the frequency axis. The control region may be configured as one or more OFDM symbols on the time axis, which may be defined as a control region duration (control resource set duration) 404. Figure 4 In the example shown in FIG. 4 , control region #1 401 may be configured as a control region duration of 2 symbols, and control region #2 402 may be configured as a control region duration of 1 symbol.

[0112] The aforementioned control region in 5G can be configured in the UE by the base station via higher layer signaling (e.g., system information, MIB, and RRC signaling). Configuring the control region in the UE means providing information such as the identification of the control region, the frequency position of the control region, and the symbol length of the control region. For example, the information in Table 7 below may be included.

[0113]

Table 7

[0114]

[0115]

[0116] In Table 7, tci-StatesPDCCH (abbreviated as transmission configuration indication (TCI) state) configuration information may include information about one or more synchronization signal (SS) / physical broadcast channel (PBCH) block indices or channel state information reference signal (CSI-RS) indices having a quasi co-location (QCL) relationship with a DMRS transmitted in a corresponding control region.

[0117] Figure 5 An example of a basic unit of time and frequency resources constituting a downlink control channel that can be used in 5G is shown. Figure 5 , a basic unit of time and frequency resources included in a control channel may be referred to as a resource element group (REG) 503, and a REG 503 may be defined as one OFDM symbol 501 on a time axis and one physical resource block (PRB) 502 on a frequency axis, i.e., 12 subcarriers. The base station may configure a downlink control channel allocation unit by cascading REGs 503.

[0118] like Figure 5 As shown in FIG. 5 , if the basic unit for allocating a downlink control channel in a 5G system is a control channel element (CCE) 504, one CCE 504 may be composed of a plurality of REGs 503. Figure 5 For example, REG 503 shown in FIG. 5A may include 12 REs, and when 1 CCE 504 includes 6 REGs 503, 1 CCE 504 may include 72 REs. In the case where a downlink control region is configured, the corresponding region 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 control region and then transmitted. CCEs 504 within the control region may be distinguished by numbering, and the numbering of CCEs 504 may be assigned according to a logical mapping scheme.

[0119] Figure 5 The basic unit REG 503 of the downlink control channel shown in FIG. 5 may include both the RE to which the DCI is mapped and the area to which the DMRS 505 corresponding to the reference signal for decoding the RE is mapped. Figure 5 As shown, 3 DMRS 505 can be sent within 1 REG 503. Depending on the aggregation level (AL), the number of CCEs required to send the PDCCH can be 1, 2, 4, 8 or 16, and different numbers of CCEs can be used to achieve link adaptation of the downlink control channel. For example, in the case of AL=L, a single downlink control channel can be sent via L CCEs. The UE needs to detect the signal without knowing the information on the downlink control channel, where a search space representing a set of CCEs is defined for blind decoding. The search space is a candidate set of downlink control channels including CCEs, which the UE needs to try to decode at a given aggregation level, and since there are various aggregation levels that constitute a bundle with 1, 2, 4, 8 or 16 CCEs, the UE can have multiple search spaces. A search space set can be defined as a set of search spaces at all configured aggregation levels.

[0120] The search space may include a common search space and a UE-specific search space. A certain group of UEs or all UEs may monitor the common search space of the PDCCH in order to receive cell common control information, such as paging messages or dynamic scheduling for system information. For example, PDSCH scheduling allocation information for the transmission of SIBs including cell operator information, etc. may be received by monitoring the common search space of the PDCCH. Since a certain group of UEs or all UEs need to receive the PDCCH, the common search space may be defined as a set of predetermined CCEs. Scheduling allocation information for UE-specific PDSCH or PUSCH may be received by monitoring the UE-specific search space of the PDCCH. The UE-specific search space may be defined as a UE-specific function based on the UE's identity and various system parameters.

[0121] In 5G, the base station may configure the parameters of the PDCCH search space for the UE through higher layer signaling (e.g., SIB, MIB, and RRC signaling). For example, the base station may configure the number of PDCCH candidates for each aggregation level L, the monitoring periodicity of the search space, the monitoring timing in units of symbols in the time slot of the search space, the search space type (common search space or UE-specific search space), the combination of RNTI and DCI format monitored in the search space, the control region index used to monitor the search space, etc. For example, the information in Table 8 below may be included.

[0122]

Table 8

[0123]

[0124]

[0125] According to the configuration information, the base station may configure one or more search space sets in the UE. According to some embodiments, the base station may configure search space set 1 and search space 2 in the UE, and may perform configuration so that DCI format A scrambled by X-RNTI in search space set 1 is monitored in the common search space, and DCI format B scrambled by Y-RNTI in search space set 2 is monitored in the UE-specific search space.

[0126] 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 may be configured as common search spaces, and search space set #3 and search space set #4 may be configured as UE-specific search spaces.

[0127] 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 embodiments:

[0128] - DCI format 0_0 / 1_0 with CRC scrambled by C-RNTI, CS-RNTI, SP-CSI-RNTI, RA-RNTI, TC-RNTI, P-RNTI, SI-RNTI;

[0129] - DCI format 2_0 with CRC scrambled by SFI-RNTI;

[0130] - DCI format 2_1 with CRC scrambled by INT-RNTI;

[0131] -DCI format 2_2 with CRC scrambled by TPC-PUSCH-RNTI, TPC-PUCCH-RNTI; and

[0132] -DCI format 2_3 with CRC scrambled by TPC-SRS-RNTI.

[0133] 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:

[0134] - DCI format 0_0 / 1_0 with CRC scrambled by C-RNTI, CS-RNTI, TC-RNTI; and

[0135] -DCI format 1_0 / 1_1 with CRC scrambled by C-RNTI, CS-RNTI, TC-RNTI.

[0136] The specified RNTI can be defined and used as follows:

[0137] -Cell RNTI (C-RNTI): used for UE-specific PDSCH scheduling;

[0138] - Temporary cell RNTI (TC-RNTI): used for UE-specific PDSCH scheduling;

[0139] -Configured Scheduling RNTI (CS-RNTI): used for semi-statically configured UE-specific PDSCH scheduling;

[0140] - Random access RNTI (RA-RNTI): used for PDSCH scheduling during random access;

[0141] - Paging RNTI (P-RNTI): used to schedule the PDSCH on which paging is sent;

[0142] - System Information RNTI (SI-RNTI): used to schedule the PDSCH on which system information is sent;

[0143] -Interrupt RNTI (INT-RNTI): used to indicate whether to puncture PDSCH;

[0144] - Transmit power control for PUSCH RNTI (TPC-PUSCH-RNTI): used to indicate the power control command for PUSCH;

[0145] - Transmit Power Control for PUCCH RNTI (TPC-PUCCH-RNTI): used to indicate the power control command for PUCCH; and / or

[0146] - Transmit Power Control of SRS RNTI (TPC-SRS-RNTI): used to indicate the power control command of SRS.

[0147] The above specified DCI format may conform to the following definition.

[0148]

Table 9

[0149]

[0150] In 5G, the search space of aggregation level L in control resource set s and control region p can be expressed as the following Equation 1.

[0151] [Equation 1]

[0152]

[0153] -L: aggregation level;

[0154] -n CI : carrier index;

[0155] -n CCE，p : The total number of CCEs in the control resource set p;

[0156] - : time slot index;

[0157] - : The number of PDCCH candidates at aggregation level L;

[0158] - =0,…, -1: PDCCH candidate index of aggregation level L;

[0159] -i=0,…,L-1;

[0160] - , Y p，-1 =nRNTI≠0, for p mod 3=0, A p =39827, for pmod 3=1, A p = 39829, for p mod 3 = 2, A p =39839, D=65537;

[0161] -n RNTI : UE identity; and

[0162] - The value may correspond to 0, in case of a common search space.

[0163] - The value may correspond to a value that varies according to the UE identity (C-RNTI or ID configured in the UE by the base station) and the time index, in the case of a UE-specific search space.

[0164] Since multiple search space sets can be configured as different parameters (e.g., parameters in Table 9) in 5G, the search space set monitored by the UE may be different each time. For example, when search space set #1 is configured on an X time slot period, search space set #2 is configured on a Y time slot period, and X and Y are different from each other, the UE may monitor all search space sets #1 and search space sets #2 in a specific time slot, and monitor one of search space set #1 and search space set #2 in another specific time slot.

[0165] [QCL, TCI status]

[0166] In a wireless communication system, one or more different antenna ports (or replaced with one or more channels, signals and combinations thereof, but for convenience, generally referred to as different antenna ports in the following description of the present disclosure) can be associated with each other through a quasi co-location (QCL) configuration as shown in [Table 10] below. The TCI state is to notify the QCL relationship between PDCCH (or PDCCH DMRS) and another RS ​​or channel, and the quasi co-location (QCLed) reference antenna port A (reference RS#A) and another use antenna port B (target RS#B) 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. According to 1) the time trajectory affected by average delay and delay spread, 2) the frequency trajectory affected by Doppler shift and Doppler spread, 3) the radio resource management (RRM) affected by average gain, 4) the beam management (BM) affected by spatial parameters, etc., QCL needs to associate different parameters. Therefore, NR supports four types of QCL relationships shown in [Table 10] below.

[0167]

Table 10

[0168]

[0169] The spatial Rx parameters may collectively refer to some or all of various parameters such as angle of arrival (AoA), angular spectral power (PAS) of AoA, angle of departure (AoD), PAS of AoD, transmit and receive channel correlation, transmit / receive beamforming, and spatial channel correlation.

[0170] The QCL relationship can be configured in the UE through the RRC parameters TCI-state and QCL-Info, as shown in [Table 11] below. Referring to [Table 11] below, the base station 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) of the RS (ie, the target RS) with reference to the ID of the TCI state. Here, each piece of QCL information (QCL-Info) included in the TCI state includes the serving cell index and BWP index of the reference RS indicated by the corresponding QCL information, the type and ID of the reference RS, and the QCL type, as shown in [Table 10] above.

[0171]

Table 11

[0172]

[0173] Figure 6 An example of base station beam allocation according to TCI state configuration is shown. Figure 6 , the base station can transmit information about N different beams to the UE through N different TCI states. Figure 6 When N=3 as shown, the base station can notify that the QCL type 2 parameters included in the three TCI states 600, 605 and 610 are associated with the CSI-RS or SSB corresponding to different beams to be configured as QCL type D, and the antenna ports indicating different TCI states 600, 605 and 610 are associated with different spatial Rx parameters (i.e., different beams).

[0174] The following [Table 12] to [Table 16] show valid TCI state configurations according to the target antenna port type.

[0175] [Table 12] shows the valid TCI state configuration when the target antenna port is a CSI-RS (TRS) for tracking. TRS is called NZP CSI-RS, which is not configured with repetition parameters, and trs-Info is configured as true in CSI-RS. The third configuration in [Table 12] can be used for non-periodic TRS.

[0176]

Table 12

[0177]

[0178] [Table 13] shows a valid TCI state configuration when the target antenna port is a CSI-RS for CSI. The CSI-RS for CSI is an NZP CSI-RS, which is not configured with a parameter indicating repetition (eg, a repetition parameter) and trs-Info in the CSI-RS is not configured to true.

[0179]

Table 13

[0180]

[0181] [Table 14] shows the valid TCI state configuration when the target antenna port is the CSI-RS for beam management (BM) (which has the same meaning as the CSI-RS for L1 RSRP reporting). Among the CSI-RS, the CSI-RS for BM is the NZP CSI-RS, its repetition parameter is configured to have a value of on or off, and trs-Info is not configured to true.

[0182]

Table 14

[0183]

[0184] [Table 15] shows a valid TCI state configuration when the target antenna port is PDCCH DMRS.

[0185]

Table 15

[0186]

[0187] [Table 16] shows the valid TCI state configuration when the target antenna port is PDSCH DMRS.

[0188]

Table 16

[0189]

[0190] In the typical QCL configuration method through [Table 12] to [Table 16], the target antenna port and the reference antenna port for each operation are configured and operated as "SSB" -> "TRS" -> "CSI-RS for CSI, CSI-RS for BM, PDCCH DMRS, or PDSCH DMRS". Therefore, the reception operation of the UE can be assisted by associating statistical characteristics that can be measured from the SSB and TRS with the corresponding antenna port.

[0191] [PDCCH: related to TCI status]

[0192] Specifically, the combination of TCI states that can be applied to the PDCCH DMRS antenna port is as shown in [Table 17] below. In [Table 17], the fourth row is a combination assumed by the UE before RRC configuration, and configuration after RRC is impossible.

[0193]

Table 17

[0194]

[0195] NR supports Figure 7 The hierarchical signaling method shown is used for dynamic allocation of PDCCH beams. Figure 7 is a view showing an example of a TCI state allocation method in a wireless communication system according to an embodiment of the present disclosure.

[0196] refer to Figure 7 , the base station may configure N TCI states 705, 710, ..., 720 in the UE through RRC signaling 700, and configure some of them as TCI states for CORESET (725). Thereafter, the base station may indicate one of TCI states 730, 735, and 740 for CORESET to the UE through MAC CE signaling (745). The UE receives the PDCCH based on the beam information included in the TCI state indicated by the MAC CE signaling.

[0197] Figure 8 The TCI indication MAC CE signaling structure for PDCCH DMRS is shown. Figure 8 , TCI indication MAC CE signaling for PDCCH DMRS is configured by 2 bytes (16 bits) and includes a 5-bit serving cell ID 815 , a 4-bit CORESET ID 820 , and a 7-bit TCI state ID 825 .

[0198] Fig. 9 The structure of the beam configuration for CORESET and search space is shown. Fig. 9 , the base station may indicate one state (905) in the TCI state list included in the configuration of the CORSET 900 through MAC CE signaling. Thereafter, before indicating another TCI state to the corresponding CORESET through other MAC CE signaling, the UE considers that the same QCL information 905 (beam #1) is applied to one or more search spaces 910, 915, and 920 connected to the CORESET.

[0199] The base station 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 the TCI state in CORESET #1, and the base station may send a command for activating TCI state #0 assumed as the TCI state of CORESET #1 to the UE through a MAC CE. The UE may correctly receive the DMRS of the corresponding CORESET based on the QCL information in the activated TCI state according to the activation command for the TCI state received through the MAC CE.

[0200] In the event that the UE does not receive a MAC CE activation command for the TCI state of CORESET#0 configured as a CORESET with index 0 (CORESET#0), the UE may assume that the DMRS transmitted in CORESET#0 is quasi-co-located with the SS / PBCH blocks identified in the initial access procedure or the non-contention based random access procedure not triggered by a PDCCH command.

[0201] In the event that the UE does not receive configuration of a 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 the TCI states for a CORESET (CORESET#X) configured with an index value other than 0, the UE may assume that the DMRS sent in CORESET#X is quasi-co-located with the SS / PBCH blocks identified during the initial access procedure.

[0202] [PDSCH: related to frequency resource allocation]

[0203] Fig.10 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.

[0204] Fig.10 Three frequency axis resource allocation methods of type 0 1000, type 1 1005, and dynamic switching 1010 that can be configured by a higher layer in an NR wireless communication system are shown.

[0205] refer to Fig.10 , when the UE is configured to use only resource type 0 (1000) by higher layer signaling, some DCIs for allocating PDSCH to the corresponding UE include a bitmap of NRBG bits. The conditions are described again below. In this case, NRBG is the number of resource block groups (RBGs) determined as shown in [Table 18] below according to the BWP size allocated by the BWP indicator and the high-level parameter rbg-Size, and data is transmitted to the RBG indicated by the bitmap as 1.

[0206]

Table 18

[0207]

[0208] In the case where the UE is configured to use only resource type 1 through higher layer signaling (1005), some DCIs for allocating PDSCH to the corresponding UE have the following characteristics: The base station can configure the frequency axis resources of length 1025 and the starting VRB 1020 allocated sequentially therefrom.

[0209] In the case where the UE is configured to use both resource type 0 and resource type 1 through higher layer signaling (1010), some pieces of DCI for allocating PDSCH to the corresponding UE include frequency-axis resource allocation information of a bit of a larger value 1035 of a payload 1015 for configuring resource type 0 and payloads 1025 and 1020 for configuring resource type 1. Here, one bit may be added to the first part (MSB) of the frequency-axis resource allocation information within the DCI, and may indicate the use of resource type 0 when the corresponding bit is "0", and may indicate the use of resource type 1 when the corresponding bit is "1".

[0210] [PDSCH / PUSCH: related to time resource allocation]

[0211] The following describes a time domain resource allocation method for a data channel in a next-generation mobile communication system (5G or NR system).

[0212] The base station may configure a table for time domain resource allocation information on PDSCH and PUSCH for the UE via higher layer signaling (e.g., RRC signaling). A table including up to 16 entries (maxNrofDL-Allocations=16) may be configured for PDSCH, and a table including up to 16 entries (maxNrofUL-Allocations=16) may be configured for PUSCH. In an embodiment, 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 of receiving the PDCCH and the time point of transmitting the PDSCH scheduled by the received PDCCH, and represented as K0), PDCCH to PUSCH slot timing (corresponding to the time interval in time slots between the time point of receiving the PDCCH and the time point of transmitting the PUSCH scheduled by the received PDCCH, and represented as K2), information about the position and length of the starting symbol in which the PDSCH or PUSCH is scheduled within the slot, the mapping type of the PDSCH or PUSCH, etc. For example, the information shown in the following [Table 19] or [Table 20] can be sent from the base station to the UE.

[0213]

Table 19

[0214]

[0215]

Table 20

[0216]

[0217] The base station may notify the UE of one of the entries in the table for time domain resource allocation information via L1 signaling (e.g., DCI) (e.g., the entry may be indicated by a "time domain resource allocation" field in the DCI). The UE may acquire the time domain resource allocation information for the PDSCH or PUSCH based on the DCI received from the base station.

[0218] Fig.11 An example of time axis resource allocation of a PDSCH in a wireless communication system according to an embodiment of the present disclosure is shown.

[0219] refer to Fig.11 , the base station can use the subcarrier spacing (SCS) (μ PDSCH , μ PDCCH ), scheduling offset (K0) value, and OFDM symbol start position 1100 and length 1105 within a time slot 1110 dynamically indicated by DCI to indicate the time axis position of the PDSCH resource.

[0220] Fig.12 An example of time axis resource allocation according to subcarrier spacing of a data channel and a control channel in a wireless communication system according to an embodiment of the present disclosure is shown.

[0221] refer to Fig.12 , the subcarrier spacing of the data channel and the control channel is the same as each other (μ PDSCH =μ PDCCH ), the time slot numbers for data and control are the same as each other, and thus the base station and the UE can generate a scheduling offset according to a predetermined time slot offset K0. On the other hand, in the case where the subcarrier spacings of the data channel and the control channel are different from each other (μ PDSCH ≠μ PDCCH ), the time slot numbers for data and control are different from each other, and thus the base station and the UE may generate a scheduling offset according to a predetermined time slot offset K0 based on the subcarrier spacing of the PDCCH.

[0222] [PDSCH: TCI state activated MAC-CE]

[0223] The beam configuration method for PDSCH will be described below. Fig.131300 is a view showing an example of a process for beam configuration and activation for PDSCH. A list of TCI states for PDSCH may be indicated by a higher layer list such as RRC (1300). The list of TCI states may be indicated by, for example, tci-StatesToAddModList and / or tci-StatestorReleaseList in the PDSCH-Config IE for each BWP. Next, a portion of the TCI state list may be activated by MAC-CE (1320). The maximum number of TCI states to be activated may be determined based on the capabilities reported by the UE. The TCI state of PDSCH may correspond to one TCI state indicated by DCI among the TCI states activated by MAC CE (1340).

[0224] Fig.14 An example of a MAC-CE structure for a PDSCH TCI state activation / deactivation MAC CE structure is shown.

[0225] The meaning of each field in the MAC CE 1400 and the configurable value of each field are as follows.

[0226] - Serving Cell ID (Serving Cell Identity) 1410: This field indicates the identity of the serving cell to which the MAC CE applies. The length of the field is 5 bits. If the indicated serving cell is configured as part of simultaneousTCI-UpdateList1 or simultaneousTCI-UpdateList2 as specified in TS 38.331, this MAC CE applies to all serving cells configured in the set simultaneousCI-UpdateList1 or simultaneousCI-UpdateList2 respectively;

[0227] - BWP ID (Bandwidth Part Identification) 1415: This field indicates the DL BWP to which the MAC CE applies as the code point of the DCI Bandwidth Part Indicator field as specified in TS 38.212. The length of the BWP ID field is 2 bits. If this MAC CE applies to a serving cell set, this field is ignored;

[0228] -Ti (TCI State Identifier, 1420): If there is a TCI state with TCI-StateId 1 as specified in TS 38.331, then this field indicates the activation / deactivation state of the TCI state with TCI-StateId 1, otherwise the MAC entity can ignore the Ti field. The Ti field is set to 1 to indicate that the TCI state with TCI-StateId 1 can be activated and mapped to the codepoint of the DCI transmission configuration indication field, as specified in TS 38.214. The Ti field is set to 0 to indicate that the TCI state with TCI-StateId 1 can be deactivated and not mapped to the codepoint of the DCI transmission configuration indication field. The codepoint to which the TCI state is mapped is determined by its ordinal position among all TCI states with the Ti field set to 1, that is, the first TCI state with the Ti field set to 1 can be mapped to the codepoint value 0, the second TCI state with the Ti field set to 1 can be mapped to the codepoint value 1, and so on. The maximum number of activated TCI states is 8; and

[0229] - CORESET Pool ID 1405: This field indicates that the mapping between the activated TCI state and the codepoint indicated by the DCI transmission configuration set by field Ti is specific to the ControlResourceSetId configured with the CORESET Pool ID, as specified in TS 38.331. This field set to 1 indicates that this MAC CE can be applied to DL transmissions scheduled by the CORESET with CORESET Pool ID equal to 1, otherwise, this MAC CE can be applied to DL transmissions scheduled by the CORESET with CORESET Pool ID equal to 0. If coresetPoolIndex is not configured for any CORESET, the MAC entity may ignore the CORESET Pool ID field in the MAC CE when receiving the MAC CE. If the serving cell in the MAC CE is configured in a cell list containing more than one serving cell, the CORESET PoolID field may be ignored when receiving the MAC CE.

[0230] [About UE Capability Report]

[0231] In LTE and NR, the UE can perform a process of reporting the capabilities supported by the UE to the corresponding base station in a state where the UE is connected to the serving base station. In the following description, this is referred to as UE capability reporting.

[0232] The base station may send a UE capability query message corresponding to a request for a capability report to a UE in a connected state. The message may include a UE capability request for each radio access technology (RAT) type of the base station. The request for each RAT type may include supported frequency band combination information, etc. In addition, in the case of a UE capability query message, the UE capability for each of the multiple RAT types may be requested through one RRC message container sent by the base station, or the base station 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 for NR, LTE, E-UTRA-NR dual connectivity (EN-DC) and multi-RAT dual connectivity (MR-DC) may be made. In addition, the UE capability query message is usually initially sent after the UE is connected to the base station, but may be requested at any time when the base station needs it.

[0233] In the above operation, the UE that receives the UE capability report request from the base station configures the UE capability according to the RAT type and frequency band information requested by the base station. The method for UE to configure UE capability in the NR system will be described below.

[0234] In the case where the UE receives a list of LTE and / or NR bands from the base station through a UE capability request, the UE configures a frequency band combination (BC) for EN-DC and NR standalone (SA). That is, the UE configures a candidate list of BCs for EN-DC and NR SA to the base station based on the requested bands through FreqBandList. The bands have priorities as described in FreqBandList in turn.

[0235] In the case where the base station sets the "eutra-nr-only" flag or the "eutra" flag and requests UE capability reporting, the UE completely removes the NR SA BC from the configured BC candidate list. Such an operation can only occur when the LTE base station (eNB) makes a request for "eutra" capability.

[0236] Thereafter, the UE removes the fallback BC from the candidate list of BCs configured in the above operation. Here, 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 operation is applied to MR-DC, i.e., the LTE band. The BC left after this operation corresponds to the final "candidate BC list".

[0237] The UE selects a BC suitable for the requested RAT type in the final "candidate BC list" and selects the BC to be reported. In this operation, the UE configures the supportedBandCombinationList according to the determined order. That is, the UE configures the UE capabilities and BCs to be reported according to the pre-configured order of rat-Type (nr->eutra-nr->eutra). In addition, the UE configures featureSetCombination for the configured supportedBandCombinationList, and configures a list of "candidate feature set combinations" in the candidate BC list, from which a list of fallback BCs (including capabilities at the same or lower level) is received. The "candidate feature set combination" can include all feature set combinations of NR and EUTRA-NR BCs, and can be obtained from the feature set combinations of UE-NR-Capabilities and UE-MRDC-Capabilities containers.

[0238] In case the requested rat-Type is eutra-nr and affects, featureSetCombinations are included in both containers of UE-MRDC-Capabilities and UE-NR-Capabilities. However, NR feature sets only include UE-NR-Capabilities.

[0239] After the UE capability is configured, the UE transmits a UE capability information message including the UE capability to the base station. The base station performs transmission / reception management and scheduling suitable for the corresponding UE based on the UE capability received from the UE.

[0240] [About NC-JT]

[0241] According to an embodiment of the present disclosure, non-coherent joint transmission (NC-JT) may be used for a UE to receive a PDSCH from multiple TRPs.

[0242] Unlike conventional systems, 5G wireless communication systems support not only services that require high transmission rates, but also services with very short transmission delays and services that require high connection density. In a wireless communication network including multiple cells, transmission and reception points (TRPs), or beams, cooperative communication (coordinated transmission) between individual cells, TRPs, or / and beams can meet various service requirements by increasing the strength of the signal received by the UE or effectively controlling interference between cells, TRPs, or / and beams.

[0243] Joint transmission (JT) is one of the typical transmission technologies used for the above-mentioned cooperative communication, and is a technology used to increase the strength or throughput of the signal received by the UE by sending the signal to one UE via multiple different cells, TRPs and / or beams. The characteristics of the channel between the UE and each cell, TRP and / or beam may vary to a large extent, and specifically, non-coherent joint transmission (NC-JT) supporting non-coherent precoding between cells, TRPs and / or beams may require separate precoding, MCS, resource allocation, TCI indication, etc. according to the channel characteristics of each link between the UE and the cell, TRP and / or beam.

[0244] NC-JT can be applied to at least one of the downlink shared channel (PDSCH), the downlink control channel (PDCCH), the uplink shared channel (PUSCH), and the uplink control channel (PUCCH). In PDSCH transmission, transmission information such as precoding, MCS, resource allocation, and TCI can be indicated by DL DCI, and can be independently indicated for each cell, TRP, or / and beam used for NC-JT. This is the main factor that increases the payload required for DL ​​DCI transmission, which may have an adverse effect on the reception performance of the PDCCH used to send DCI. Therefore, in order to support JT of PDSCH, the trade-off between the amount of DCI information and the reception performance of the control information needs to be carefully designed.

[0245] Fig.15 An example of antenna port configuration and resource allocation for cooperative communication in a wireless communication system according to an embodiment of the present disclosure is shown.

[0246] refer to Fig.15 , examples for PDSCH transmission are described for each scheme of joint transmission (JT), and examples for allocating radio resources for each TRP are described.

[0247] An example 1500 of coherent joint transmission (C-JT) supporting coherent precoding between corresponding cells, TRPs, or / and beams is shown. In the case of C-JT, TRP A 1505 and TRP B 1510 send a single data (PDSCH) to the UE 1515, and joint precoding may be performed in multiple TRPs. This may mean sending DMRS through the same DMRS port so that TRP A 1505 and TRP B 1510 send the same PDSCH. For example, TRP A 1505 and TRP B 1510 may send DMRS to the UE through DMRS port A and DMRS port B, respectively. In this case, the UE may receive a piece of DCI information for receiving a PDSCH demodulated based on the DMRS sent through DMRS port A and DMRS port B.

[0248] Fig.15 An example 1520 of supporting non-coherent joint transmission (NC-JT) with non-coherent precoding between individual cells, TRPs, or / and beams for PDSCH transmission is shown. In the case of NC-JT, the PDSCH is sent to the UE 1535 for each cell, TRP, or / and beam, and a separate precoding may be applied to each PDSCH. Each cell, TRP, or / and beam may send different PDSCHs or different PDSCH layers to the UE, thereby improving throughput compared to a single cell, TRP, or / and beam transmission. In addition, each cell, TRP, or / and beam may repeatedly send the same PDSCH to the UE, thereby improving reliability compared to a single cell, TRP, or / and beam transmission. For ease of description, cells, TRPs, or / and beams are collectively referred to as TRPs.

[0249] Here, for PDSCH transmission, various wireless resource allocations can be considered, such as the case 1540 where the frequency and time resources used by multiple TRPs for PDSCH transmission are all the same, the case 1545 where the frequency and time resources used by multiple TRPs do not overlap at all, and the case 1550 where some of the frequency and time resources used by multiple TRPs overlap with each other.

[0250] To support NC-JT, various forms, structures, and relationships of DCI may be considered to simultaneously allocate multiple PDSCHs to one UE.

[0251] Fig.16 An example of the configuration of DCI for NC-JT in a wireless communication system according to an embodiment of the present disclosure is shown, where each TRP sends a different PDSCH or a different PDSCH layer to the UE.

[0252] refer to Fig.16, case #1 1600 is an example in which, in the case where (N-1) different PDSCHs are sent 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 sent from the (N-1) additional TRPs is sent independently of the control information of the PDSCH sent by the serving TRP. That is, the UE can obtain the control information of the PDSCH sent from different TRPs (TRP#0 to TRP#(N-1)) through independent DCIs (DCI#0~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 sent by different TRPs, differences between DCI coverage may occur and reception performance may be degraded.

[0253] Case #2 1605 is an example in which, in the case where (N-1) different PDSCHs are sent from (N-1) additional TRPs (TRP#1 to TRP#(N-1)) in addition to the serving TRP (TRP#0) used for a single PDSCH transmission, control information of PDSCHs of multiple (N-1) additional TRPs is sent, and each DCI depends on the control information of the PDSCH sent from the serving TRP.

[0254] For example, DCI#0, which is control information of the PDSCH transmitted 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 transmitted from the collaborative TRPs (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 normal DCI (nDCI) for transmitting control information related to the PDSCH transmitted from the serving TRP, the sDCI for transmitting control information of the PDSCH transmitted from the collaborative TRP has a smaller payload and thus may include reserved bits compared with the nDCI.

[0255] In case #2, the degree of freedom of each PDSCH control or allocation can be limited according to the content of the information elements included in the sDCI, but the reception capability of sDCI becomes better than that of nDCI, so the probability of generating differences between DCI coverage may become lower.

[0256] Case #3 1610 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)) in addition to the serving TRP (TRP#0) for a single PDSCH transmission, one piece of 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 cell.

[0257] For example, 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 aggregated in one "secondary" DCI (sDCI) and sent. For example, the sDCI may include at least one piece of HARQ-related information, such as frequency domain resource allocation, time domain resource allocation, and MCS of the collaborative TRP. 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).

[0258] In case #3 1610, 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 1600 or case #2 1605, case #3 can have smaller complexity of DCI blind decoding of the UE.

[0259] Case #4 1615 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 DCI of control information of the PDSCH transmitted from the serving TRP. That is, the UE can obtain control information of the PDSCH transmitted from different TRPs (TRP#0 to TRP#(N-1)) through a single DCI. In case #4 1615, the complexity of DCI blind decoding of the UE may not be increased, but the degree of freedom of PDSCH control or allocation may be lower because the number of collaborative TRPs is limited according to the long DCI payload limitation.

[0260] In the following description and embodiments, sDCI may refer to various multiple supplementary DCIs including PDSCH control information sent in a collaborative TRP, such as a shortened DCI, an auxiliary DCI, or a normal DCI (DCI formats 1_0 and 1_1 mentioned above), and unless specific limitations are mentioned, the corresponding description may be similarly applied to the various supplementary DCIs.

[0261] In the following description and embodiments, case #1 1600, case #2 1605, and case #3 1610 in which one or more DCIs (PDCCHs) are used to support NC-JT may be classified as NC-JT based on multiple PDCCHs, and case #4 1615 in which a single DCI (PDCCH) is used to support NC-JT may be classified as NC-JT based on a single PDCCH. In PDSCH transmission based on multiple PDCCHs, a CORESET for scheduling DCI for a service TRP (TRP#0) may be separated from a CORESET for scheduling DCI for a collaborative TRP (TRP#1 to TRP#(N-1)). Methods of distinguishing CORESETs may include a distinguishing method by a higher 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 having multiple layers instead of scheduling multiple PDSCHs, and multiple layers may be transmitted from multiple TRPs. Here, the correlation between the layer and the TRP of the sending corresponding layer can be indicated by a transmission configuration indicator (TCI) indication for the layer.

[0262] When actually applied, the "collaborative TRP" of the embodiments of the present disclosure may be replaced with various terms such as "collaborative panel" or "collaborative beam".

[0263] In the embodiments of the present disclosure, considering the conditions, "a case where NC-JT is applied" may be interpreted differently as "a case where the UE simultaneously receives one or more PDSCHs in one BWP", "a case where the UE simultaneously receives PDSCHs in one BWP based on two or more transmission configuration indicator (TCI) indications", and "a case where the PDSCH received by the UE is associated with one or more DMRS port groups", but for ease of description, one expression is used.

[0264] In the present disclosure, the wireless protocol structure for NC-JT can be used differently according to the TRP development scenario. As an example, in a case where there is a small backhaul delay or no backhaul delay between the cooperative TRPs, a method using a structure based on MAC layer multiplexing (a method similar to CA) can be used. On the other hand, in a case where the backhaul delay between the cooperative TRPs is too large to be ignored (for example, when 2ms or more is required to exchange information such as CSI, scheduling, and HARQ-ACK between the cooperative TRPs), a method that ensures a delay-robust characteristic can be used through an independent structure for each TRP from the RLC layer (a method similar to DC).

[0265] A UE supporting C-JT and / or NC-JT may receive C-JT and / or NC-JT related parameters or setting values ​​from a higher layer configuration, and set the UE's RRC parameters based on the parameters or setting values. For higher layer configuration, the UE may use UE capability parameters, such as tci-StatePDSCH. The UE capability parameters (e.g., tci-StatePDSCH) may define TCI states for the purpose of PDSCH transmission, the number of TCI states may be configured as 4, 8, 16, 32, 64, and 128 in FR1 and as 64 and 128 in FR2, and a maximum of 8 states that may be indicated by 3 bits of the TCI field of the DCI may be configured through a MAC CE message among the configured number. 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 higher layer configuration to MAC CE configuration can be applied to beamforming indication or beamforming change command for at least one PDSCH in one TRP.

[0266] [Multiple TRPs based on multiple DCIs]

[0267] As an embodiment of the present disclosure, a multi-TRP transmission method based on multi-DCI will be described. The multi-TRP transmission method based on multi-DCI can configure a downlink control channel for NC-JT based on multiple PDCCHs.

[0268] When transmitting DCI for scheduling PDSCH for each TRP, NC-JT based on multiple PDCCHs may include a search space or CORESET distinguished according to TRP. The search space or CORESET for each TRP may be configured as at least one of the following cases.

[0269] *Higher layer index configuration for each CORESET: The CORESET configuration information configured by the higher layer may include an index value, and the TRP that sends the PDCCH from the corresponding CORESET may be distinguished by the configured index value of each CORESET. In other words, in a CORESET group having the same higher layer index value, the same TRP may be considered to send a PDCCH or a PDCCH that sends a PDSCH that schedules the same TRP. The above index for each CORESET may be referred to as CORESETPoolIndex, and the PDCCH may be considered to be sent from the same TRP of the CORESET in which the same CORESETPoolIndex value is configured. Regarding a CORESET in which a CORESETPoolIndex value is not configured, it may be considered that a basic value is configured for CORESETPoolIndex, and the basic value may be 0.

[0270] -In the present disclosure, when the type of CORESETPoolIndex of multiple CORESETs included in PDCCH-Config as higher layer signaling exceeds 1, that is, when the CORESETs have different CORESETPoolIndex, the UE can determine that the base station can use a multi-TRP transmission method based on multi-DCI.

[0271] -On the contrary, in the present disclosure, when the type of CORESETPoolIndex included in multiple CORESETs included in the PDCCH-Config as higher layer signaling is 1, that is, when all CORESETs have a CORESETPoolIndex of 0 or 1, the UE can determine that the base station does not use a multi-TRP transmission method based on multi-DCI, but uses a single TRP for transmission.

[0272] *Configuration of multiple PDCCH-Configs: Multiple PDCCH-Configs can be configured in one BWP, and each PDCCH-Config can include a PDCCH configuration for each TRP. In other words, it can be considered that a list of CORESETs for each TRP and / or a list of search spaces for each TRP are configured in one PDCCH-Config, and one or more CORESETs and one or more search spaces included in one PDCCH-Config correspond to a specific TRP.

[0273] *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, it can be considered that the corresponding CORESET is sent through the same TRP or the PDCCH for scheduling the PDSCH of the same TRP is sent in the corresponding CORESET.

[0274] *Configuration of search space beam / beam group: A beam or beam group can be 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, it can be considered that the same TRP sends PDCCH in the corresponding search space or sends PDCCH for scheduling PDSCH of the same TRP in the corresponding search space.

[0275] By distinguishing the CORESET or search space of each TRP as described above, the PDSCH and HARQ-ACK information of each TRP can be classified, and therefore, an independent HARQ-ACK codebook can be generated for each TRP and independent PUCCH resources can be used.

[0276] The above configuration can be independent for each cell or BWP. For example, two different CORESETPoolIndex values ​​can be configured for the PCell, while the CORESETPoolIndex value can be not configured for a specific SCell. In this case, it is considered that NC-JT is configured in the PCell, and NC-JT is not configured in the SCell where the CORESETPoolIndex value is not configured.

[0277] The PDSCH TCI state activation / deactivation MAC-CE applicable to the multi-TRP transmission method based on multi-DCI can be as follows Fig.14If the UE does not receive the configuration of the CORESETPoolIndex of each of all CORESETs in the higher layer PDCCH-Config, the UE may ignore the CORESET Pool ID field 1405 in the corresponding MAC-CE 1400. If the UE is capable of supporting a multi-DCI based multi-TRP transmission method, that is, the UE has a different CORESETPoolIndex for each CORESET within the higher layer signaling PDCCH-Config, the UE may activate the TCI state in the DCI that includes the PDCCH sent from the CORESET having the CORESETPoolIndex value that is the same as the value of the CORESET Pool ID field 1405 in the corresponding MAC-CE 1400. As an example, when the value of the CORESET Pool ID field 1405 in the MAC CE 1400 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 corresponding MAC CE.

[0278] When the base station configures the UE to use the multi-DCI based multi-TRP transmission method, that is, when the type of CORESETPoolIndex of multiple CORESETs included in the higher layer signaling PDCCH-Config exceeds 1, or when the CORESETs have different CORESETPoolIndex, the UE may consider that there are the following restrictions for PDSCH scheduled by PDCCH in two CORESETs with different CORESETPoolIndex.

[0279] When the PDSCH indicated by the PDCCH in two CORESETs with different CORESETPoolIndex completely or partially overlaps, the UE may apply the TCI state indicated by the PDCCH to different CDM groups. That is, two or more TCI states may not be applied to one CDM group.

[0280] When the PDSCHs indicated by PDCCHs in two CORESETs with different CORESETPoolIndex overlap completely or partially, the UE can expect that the actual number of front-load DMRS symbols, the actual number of additional DMRS symbols, the actual positions of DMRS symbols and the DMRS types of each PDSCH are no different from each other.

[0281] The UE can expect that the BWP indicated by the PDCCH in two CORESETs with different CORESETPoolIndex is the same and the subcarrier spacing is also the same.

[0282] The UE may expect that pieces of information about the PDSCH scheduled from the PDCCHs in two CORESETs having different CORESETPoolIndex are fully included in the corresponding PDCCH.

[0283] [Multiple TRPs based on a single DCI]

[0284] As an embodiment of the present disclosure, a multi-TRP transmission method based on a single DCI will be described. The multi-TRP transmission method based on a single DCI can be used for a downlink control channel of NC-JT based on a single PDCCH configuration.

[0285] In a multi-TRP transmission method based on a single DCI, a PDSCH sent by multiple TRPs can be scheduled by one DCI. Here, the number of TCI states can be used to indicate the method of sending the number of TRPs corresponding to the PDSCH. That is, when the number of TCI states indicated by the DCI for scheduling the 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 can correspond to the TCI state activated by the MAC CE, where the number of TCI states activated by the MAC CE corresponding to the TCI code point can be 2.

[0286] For another example, at least one of all code points in the TCI state field in the DCI indicates two TCI states, and the UE may assume that the base station may perform transmission based on a multi-TRP transmission method based on a single DCI. Here, at least one code point indicating two TCI states in the TCI state field may be activated by enhancing the PDSCH TCI state activation / deactivation MAC CE.

[0287] Fig.17 An example of a MAC-CE structure for enhancing the PDSCH TCI state activation / deactivation MAC CE structure is shown. The meaning of each field in the corresponding MAC CE and the configurable value of each field are as follows.

[0288] - Serving Cell ID: This field indicates the identity of the serving cell to which the MAC CE applies. The length of the field is 5 bits. If the indicated serving cell is configured as part of simultaneousCI-UpdateList1 or simultaneousCI-UpdateList2 as specified in TS 38.331, this MAC CE applies to all serving cells configured in the set simultaneousCI-UpdateList1 or simultaneousCI-UpdateList2 respectively;

[0289] -BWP ID: This field indicates the DL BWP applied by the MAC CE as the code point of the DCI Bandwidth Part Indicator field as specified in TS 38.212. The length of the BWP ID field is 2 bits;

[0290] -Ci: This field indicates whether the octet containing the TCI status Idi,2 is present. If this field is set to "1", the octet containing the TCI status IDi,2 is present. If this field is set to "0", the octet containing the TCI status IDi,2 is not present;

[0291] -TCI State IDi,j: This field indicates the TCI state identified by TCI-StateId specified in TS 38.331, where i is the index of the codepoint of the DCI transmission configuration indication field specified in TS 38.212, and TCI State IDi,j represents the jth TCI state indicated for the i-th codepoint in the DCI transmission configuration indication field. The TCI codepoint to which the TCI state is mapped is determined by its ordinal position among all TCI codepoints with the TCI State IDi,j field set, i.e., the first TCI codepoint with TCI State ID0,1 and TCI State ID0,2 can be mapped to codepoint value 0, the second TCI codepoint with TCI State ID1,1 and TCI State ID1,2 can be mapped to codepoint value 1, and so on. Based on the indication of the Ci field, TCI State IDi,2 is optional. The maximum number of activated TCI codepoints is 8, and the maximum number of TCI states mapped to a TCI codepoint is 2; and

[0292] -R: Reserved bit, set to "0".

[0293] exist Fig.17In the embodiment of the present invention, when the value of the C0 field 1705 is 1, the corresponding MAC-CE may include TCI state ID0,2 1715 in addition to the TCI state ID0,1 field 1710. This indicates 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 corresponding code point to the UE, the UE may receive indications of two TCI states. If the value of the C0 field 1705 is 0, the corresponding MAC-CE cannot include the TCI state ID0,2 field 1715, and this indicates 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.

[0294] The above configuration may be independent for each cell or BWP. For example, although the maximum number of activated TCI states corresponding to one TCI code point in PCell is 2, the maximum number of activated TCI states corresponding to one TCI code point in a specific SCell may be 1. In this case, it may be considered to configure NC-JT in PCell but not in SCell.

[0295] [Method for distinguishing multiple TRP PDSCH repetitive transmission schemes (TDM / FDM / SDM) based on single DCI]

[0296] Next, a method for distinguishing a multi-TRP PDSCH repetition transmission scheme based on a single DCI will be described. The UE can receive instructions for different multi-TRP PDSCH repetition transmission schemes (e.g., TDM, FDM, and SDM) based on a single DCI from a base station based on the value indicated by the DCI field and the higher layer signaling configuration. The following [Table 21] shows a method for distinguishing a single TRP or multi-TRP scheme indicated to the UE based on the value of a specific DCI field and the higher layer signaling configuration.

[0297]

Table 21

[0298]

[0299] Each column in [Table 21] can be described as follows.

[0300] - Number of TCI states (second column): indicates the number of TCI states indicated by the TCI state field in the DCI, and can be one or two.

[0301] - Number of CDM groups (third column): indicates the number of different CDM groups for the DMRS ports indicated by the antenna port field in the DCI. This number can be 1, 2, or 3.

[0302] - repetitionNumber configuration and indication conditions (fourth column): There may be three conditions, depending on whether repetitionNumber is configured for all time domain resource allocation (TDRA) entries indicated by the TDRA field in the DCI, and whether the actual indicated TDRA entry includes the repetitionNumber configuration.

[0303] ■ Condition 1: When at least one of all TDRA entries that may be indicated by the time domain resource allocation field includes a configuration of repetitionNumber, and the TDRA entry indicated by the time domain resource allocation field in the DCI includes a configuration of repetitionNumber greater than 1.

[0304] ■ Condition 2: When at least one of all TDRA entries that may be indicated by the time domain resource allocation field includes a configuration of repetitionNumber and the TDRA entry indicated by the time domain resource allocation field in the DCI does not include a configuration of repetitionNumber.

[0305] ■ Condition 3: When any TDRA entry that may be indicated by the Time Domain Resource Allocation field does not include the configuration of repetitionNumber.

[0306] - Regarding repetitionScheme configuration (fifth column): Indicates whether a higher layer signaling repetitionScheme is configured. The higher layer signaling repetitionScheme can be configured with one of "tdmSchemeA", "fdmSchemeA" and "fdmSchemeB".

[0307] -Transmission scheme indicated to the UE (sixth column): Indicates the single TRP or multi-TRP scheme indicated according to the combination (first column) in [Table 24].

[0308] ■ Single TRP: Indicates PDSCH transmission based on a single TRP. If the UE is configured with pdsch-AggegationFactor in the higher layer signaling PDSCH-config, the UE can be scheduled with PDSCH repetition transmission based on a single TRP according to the configured number of times. Otherwise, the UE can be scheduled with a single PDSCH transmission based on a single TRP.

[0309] ■Single TRP TDM Scheme B: represents PDSCH repetition transmission based on time slots based on a single TRP based on time resource division. According to the above condition 1 regarding repetitionNumber, the UE repeatedly sends PDSCH on the time resource according to the number of time slots greater than 1 configured in the TDRA entry indicated by the time domain resource allocation field. Here, the starting symbol and symbol length of the PDSCH indicated by the TDRA entry are equally applied to each time slot according to the number 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 performing PDSCH repetition transmission between time slots on the time resource, but is different from the time slot aggregation scheme in dynamically determining whether to indicate repetition transmission based on the time domain resource allocation field in the DCI.

[0310] ■Multi-TRP SDM: Indicates a multi-TRP-based spatial resource division PDSCH transmission scheme. This is a method of dividing and receiving layers from each TRP, and although multi-TRP SDM is not a repetitive transmission scheme, the reliability of PDSCH transmission can be increased as the number of layers increases to reduce the coding rate. The UE 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 to receive the PDSCH, respectively.

[0311] ■Multi-TRP FDM scheme A: refers to a frequency resource division PDSCH transmission scheme based on multiple TRPs, and although this scheme is not repeated transmission like multi-TRP SDM, because there is one PDSCH transmission position (opportunity), the frequency resource amount is increased to reduce the coding rate, and thus the transmission reliability may be high. In multi-TRP FDM scheme A, two TCI states indicated by the TCI state field in DCI can be applied to frequency resources that do not overlap with each other, respectively. When the PRB bundling size is determined to be wideband and the number of RBs indicated by the frequency domain resource allocation field is N, the UE can receive the first ceil (N / 2) RBs by applying the first TCI state and the remaining floor (N / 2) RBs by applying the second TCI state. Here, ceil (.) and floor (.) are each an operator indicating rounding up or rounding down of the first decimal point. When the PRB bundling size is determined to be 2 or 4, even-numbered PRGs are received by applying the first TCI state, and odd-numbered PRGs are received by applying the second TCI state.

[0312] ■Multi-TRP FDM scheme B: represents a PDSCH repetition transmission scheme based on frequency resource division of multiple TRPs, and PDSCH can be repeatedly transmitted at each of two PDSCH transmission positions (opportunities). In multi-TRP FDM scheme B, as in multi-TRP FDM scheme A, two TCI states indicated by the TCI state field in DCI can be respectively applied to frequency resources that do not overlap with each other. When the PRB bundling size is determined to be wideband and the number of RBs indicated by the frequency domain resource allocation field is N, the UE can receive the first ceil (N / 2) RBs by applying the first TCI state and the remaining floor (N / 2) RBs by applying the second TCI state. Here, ceil (.) and floor (.) are each an operator indicating rounding up or rounding down of the first decimal point. When the PRB bundling size is determined to be 2 or 4, even-numbered PRGs are received by applying the first TCI state, and odd-numbered PRGs are received by applying the second TCI state.

[0313] ■Multi-TRP TDM scheme A: represents the PDSCH repetition transmission scheme in the time resource division time slot based on multiple TRPs. The UE has two PDSCH transmission positions (opportunities) in one time slot, and can determine the first reception position based on the starting symbol and symbol length of the PDSCH indicated by the time domain resource allocation field in the DCI. The starting symbol of the second reception position of the PDSCH can be the position of the symbol offset from the last symbol of the first transmission position according to the higher layer signaling StartingSymbolOffsetK, and the transmission position corresponding to the symbol length indicated therefrom can be determined. When the higher layer signaling StartingSymbolOffsetK is not configured, the symbol offset can be considered to be 0.

[0314] ■Multi-TRP TDM Scheme B: represents the PDSCH repetition transmission scheme between time slots based on time resource division of multiple TRPs. The UE has one PDSCH transmission position (opportunity) within a time slot, and can receive repetition transmission based on the start symbol and symbol length of the same PDSCH during the time slot corresponding to the repetitionNumber indicated by the time domain resource allocation field in the DCI. When the repetitionNumber is 2, the UE can receive the PDSCH repetition transmission of the first time slot and the second time slot by applying the first TCI state and the second TCI state, respectively. When the repetitionNumber is greater than 2, the UE can use different TCI state application methods depending on how the higher layer signaling tciMapping is configured. When tciMapping is configured as cyclicMapping, the first TCI state and the second TCI state can be applied to the first PDSCH transmission position and the second PDSCH transmission position, respectively, and the same TCI state application method is also applied to the remaining PDSCH transmission positions. When tciMapping is configured as sequentialMapping, the first TCI state can be applied to the first PDSCH transmission position and the second PDSCH transmission position, the second TCI state can be applied to the third PDSCH transmission position and the fourth PDSCH transmission position, and the same TCI state application method can be similarly applied to the remaining PDSCH transmission positions.

[0315] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The content of the present disclosure may be applicable to FDD and TDD systems. Hereinafter, in the present disclosure, higher signaling (or higher layer signaling) may be a method of sending a signal from a base station to a UE through a downlink data channel of a physical layer or from a UE to a base station through an uplink data channel of a physical layer, and may also be referred to as RRC signaling, PDCP signaling, or a media access control (MAC) control element (CE) (MACCE).

[0316] In the present disclosure, determining the priority between A and B may refer to selecting one with a higher priority and performing an operation corresponding thereto according to a predetermined priority rule, or omitting or discarding an operation corresponding to one with a lower priority, etc.

[0317] In the present disclosure, the embodiments are described above through multiple embodiments, but these are not independent, and it is possible that one or more embodiments may be applied simultaneously or in combination.

[0318] [Relationship with DMRS]

[0319] Next, the antenna field indication included in the DCI format 1_1 and DCI format 1_2 defined in the above [Table 6] will be described. The antenna port field in DCI format 1_1 and DCI format 1_2 can be represented by 4, 5 or 6 bits, and the base station can indicate the antenna port related information to the UE based on the following [Table 22] to [Table 29].

[0320] [Table 22] Antenna port (1000+DMRS port), dmrs-Type=1, maxLength=1

[0321]

[0322] [Table 23] Antenna port (1000+DMRS port), dmrs-Type=1, maxLength=1

[0323]

[0324] [Table 24] Antenna port (1000 + DMRS port), dmrs-Type = 1, maxLength = 2

[0325]

[0326] [Table 25] Antenna port (1000 + DMRS port), dmrs-Type = 1, maxLength = 2

[0327]

[0328]

[0329] [Table 26]: Antenna ports (1000+DMRS ports), dmrs-Type=2, maxLength=1

[0330]

[0331] [Table 27]: Antenna port (1000 + DMRS port), dmrs-Type = 2, maxLength = 1

[0332]

[0333] [Table 28]: Antenna ports (1000 + DMRS ports), dmrs-Type = 2, maxLength = 2

[0334]

[0335]

[0336] [Table 29]: Antenna ports (1000 + DMRS ports), dmrs-Type = 2, maxLength = 2

[0337]

[0338]

[0339] [Table 22] and [Table 23] are tables used when the dmrs-type is 1 and the maxLength is 1, [Table 24] and [Table 25] are tables used when the dmrs-type=1 and maxLength=2 are indicated, [Table 26] and [Table 27] indicate the DMRS ports used when dmrs-type=2 and maxLength=1, and [Table 28] and [Table 29] indicate the DMRS ports used when the dmrs-type is 2 and the maxLength is 2.

[0340] When the UE receives a MAC-CE for activating a code point indicating two TCI states with respect to at least one code point in the TCI state field within the DCI, the UE may receive an indication of a DMRS port by using [Table 23], [Table 25], [Table 27], and [Table 29], and otherwise, may receive an indication of a DMRS port by using [Table 22], [Table 24], [Table 26], and [Table 28]. When the UE receives an indication of a code point indicating two TCI states through the TCI state field, the UE may receive an indication of entries indicating DMRS ports 1000, 1002, and 1003 for NC-JT scheduling purposes in [Table 23], [Table 25], [Table 27], and [Table 29], and the entries may correspond to #12 in [Table 23], #31 in [Table 25], #24 in [Table 27], and #58 in [Table 29].

[0341] Regarding DCI format 1_1, if both higher layer signaling dmrs-DownlinkForPDSCH-MappingTypeA and dmrs-DownlinkForPDSCH-MappingTypeB are configured for the UE, the bit length of the antenna port field in DCI format 1_1 may be determined as max{xA, xB}, and in this case, xA and xB may represent the bit length of the antenna port field determined by dmrs-DownlinkForPDSCH-MappingTypeA and dmrs-DownlinkForPDSCH-MappingTypeB, respectively. If a PDSCH mapping type corresponding to a smaller value of xA and xB is scheduled, each MSB bit whose number is equal to |xA-xB| may be assigned 0 bits and then transmitted.

[0342] Regarding DCI format 1_2, if higher layer signaling antennaPortsFieldPresenceDCI-1-2 is not configured for the UE, the antenna port field may not exist in DCI format 1_2. That is, the length of the antenna port field may be 0 bits, and the UE may determine the DMRS port by assuming the 0th entry in [Table 22], [Table 24], [Table 26], and [Table 28]. If higher layer signaling antennaPortsFieldPresenceDCI-1-2 is configured for the UE, the bit length of the antenna port field in DCI format 1_2 may be determined similarly to the case of DCI format 1_1. If both higher layer signaling dmrs-DownlinkForPDSCH-MappingTypeA-DCI-1-2 and dmrs-DownlinkForPDSCH-MappingTypeB-DCI-1-2 are configured for the UE, the bit length of the antenna port field in DCI format 1_2 may be determined as max{xA, xB}, and in this case, xA and xB may represent 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 a PDSCH mapping type corresponding to a smaller value of xA and xB is scheduled, each MSB bit whose number is equal to |xA-xB| may be assigned 0 bits and then transmitted.

[0343] The numbers 1, 2, and 3 indicated by the number of DMRS CDM groups without data in [Table 22] to [Table 29] can indicate CDM groups {0}, {0, 1}, and {0, 1, 2}, respectively. The DMRS port shows the index of the port used in order. The antenna port can be indicated by DMRS port + 1000. The CDM group of DMRS is connected to the method of generating DMRS sequence and antenna port as shown in [Table 30] and [Table 31]. [Table 30] shows the parameters for the case of using dmrs-type = 1, and [Table 31] shows the parameters for the case of using dmrs-type = 2.

[0344] [Table 30]: Parameters for PDSCH DM-RS dmrs-type = 1.

[0345]

[0346] [Table 31]: Parameters for PDSCH DM-RS dmrs-type = 2.

[0347]

[0348] The DMRS sequence according to each parameter is determined by the following equation 2. In equation 2, p represents a DMRS port, k represents a subcarrier index, l represents an OFDM symbol index, μ represents a subcarrier spacing, and w f (k') and w t (l') represents the frequency domain orthogonal cover code (FD-OCC) coefficient and the time domain orthogonal cover code (TD-OCC) coefficient according to the k' value and l' value, respectively, and Δ represents the interval between CDM groups by using the number of subcarriers. In Equation 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, 2 and 3, The possible values ​​are 0dB, -3dB and -4.77 dB.

[0349] [Equation 2]

[0350]

[0351] 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 UE by using [Table 22] and [Table 24], if a single codeword is scheduled and entries #2, #9, #10, #11, and #12 are indicated to it by using [Table 23], if a single codeword is scheduled and entries #2, #9, #10, #11, #30, and #31 are indicated to it by using [Table 25], or if two codewords are scheduled, the UE may consider the scheduling to be single-user MIMO scheduling. That is, the UE may assume that different UEs are not scheduled to all remaining orthogonal DMRS ports other than the DMRS port assigned to the scheduled PDSCH, and may not expect multi-user MIMO (MU-MIMO) scheduling. In this case, the UE does not assume that different UEs are co-scheduled, and may not perform multi-user MIMO reception operations such as canceling, blanking, or whitening multi-user interference.

[0352] In the case of using DMRS type 2, if a single codeword is scheduled and entries #2, #10, and #23 are indicated to the UE by using [Table 26] and [Table 28], if a single codeword is scheduled and entries #2, #10, #23, and #24 are indicated to it by using [Table 27], if a single codeword is scheduled and entries #2, #10, #23, and #58 are indicated to it by using [Table 29], or if two codewords are scheduled, the UE may consider the scheduling to be single-user MIMO scheduling. That is, the UE may assume that different UEs are not scheduled to all remaining orthogonal DMRS ports other than the DMRS port assigned to the scheduled PDSCH, and may not expect multi-user MIMO scheduling. In this case, the UE does not assume that different UEs are co-scheduled, and may not perform multi-user MIMO reception operations such as canceling, blanking, or whitening multi-user interference.

[0353] The UE may not expect that although the maximum number of front-loaded DMRS symbols is configured as len2 through higher layer signaling maxLength, more than one additional DMRS symbol is configured through higher layer signaling dmrs-AdditionalPosition.

[0354] The UE may not expect that the number of actual frontloaded DMRS, the number of actual additional DMRS symbols, DMRS symbol positions, and DMRS type configuration are different for all UEs subject to multi-user MIMO scheduling.

[0355] In the case of a UE with a PRG size of 2 or 4, the UE may not expect frequency resource allocations to not match in a PRG cell grid for different UEs co-scheduled using different orthogonal DMRS ports in the same CDM group as the CDM group of DMRS ports indicated to the UE.

[0356] In the case of PDSCH scheduled by DCI formats 1_1 and 1_2, the UE may assume that the CDM groups indicated by the column “Number of DMRS CDM groups without data” in [Table 22] to [Table 29] may include DMRS ports allocated to different UEs that can be co-scheduled by a multi-user MIMO scheme and may not be used for data transmission of the corresponding UE, and the values ​​1, 2, and 3 indicated by the column “Number of DMRS CDM groups without data” in [Table 22] to [Table 29] may be understood as the indices of the CDM groups corresponding to the described values ​​corresponding to CDM groups 0, {0, 1}, and {0, 1, 2}, respectively.

[0357] If higher layer signaling dmrs-FD-OCC-disableForRank1PDSCH is configured for the UE and one DMRS port is allocated to the UE for PDSCH scheduling, the UE may not expect to allocate DMRS ports using different FD-OCCs to different UEs among different orthogonal DMRS ports belonging to the same CDM group as the CDM group of one allocated DMRS port.

[0358] Next, the antenna field indication included in the DCI format 0_1 ​​and DCI format 0_2 defined in [Table 4] above will be described. The antenna port field in DCI format 0_1 ​​and DCI format 0_2 can be represented by 3, 4 or 5 bits, and the base station can indicate antenna related information to the UE based on the following [Table 32] to [Table 47].

[0359] [Table 32] Antenna port, conversion precoder is disabled, dmrs-Type = 1, maxLength = 1, rank = 1

[0360]

[0361] [Table 33] Antenna port, conversion precoder is disabled, dmrs-Type = 1, maxLength = 1, rank = 2

[0362]

[0363] [Table 34] Antenna port, conversion precoder is disabled, dmrs-Type = 1, maxLength = 1, rank = 3

[0364]

[0365] [Table 35] Antenna port, conversion precoder is disabled, dmrs-Type = 1, maxLength = 1, rank = 4

[0366]

[0367] [Table 36] Antenna port, conversion precoder is disabled, dmrs-Type = 1, maxLength = 2, rank = 1

[0368]

[0369] [Table 37] Antenna port, conversion precoder is disabled, dmrs-Type = 1, maxLength = 2, rank = 2

[0370]

[0371] [Table 38] Antenna port, conversion precoder is disabled, dmrs-Type = 1, maxLength = 2, rank = 3

[0372]

[0373] [Table 39] Antenna port, conversion precoder is disabled, dmrs-Type = 1, maxLength = 2, rank = 4

[0374]

[0375] [Table 40] Antenna port, conversion precoder is disabled, DMRS-Type = 2, maxLength = 1, rank = 1

[0376]

[0377] [Table 41] Antenna port, conversion precoder is disabled, dmrs-Type = 2, maxLength = 1, rank = 2

[0378]

[0379] [Table 42] Antenna port, conversion precoder is disabled, dmrs-Type = 2, maxLength = 1, rank = 3

[0380]

[0381] [Table 43] Antenna port, conversion precoder is disabled, dmrs-Type = 2, maxLength = 1, rank = 4

[0382]

[0383] [Table 44] Antenna port, conversion precoder is disabled, dmrs-Type = 2, maxLength = 2, rank = 1

[0384]

[0385] [Table 45] Antenna port, conversion precoder is disabled, dmrs-Type = 2, maxLength = 2, rank = 2

[0386]

[0387] [Table 46] Antenna port, conversion precoder is disabled, dmrs-Type = 2, maxLength = 2, rank = 3

[0388]

[0389] [Table 47] Antenna port, conversion precoder is disabled, dmrs-Type = 2, maxLength = 2, rank = 4

[0390]

[0391] [Table 32] to [Table 35] are tables used when the dmrs-type is indicated to be 1 and the maxLength is 1, [Table 36] to [Table 39] are tables used when the dmrs-type=1 and maxLength=2 are indicated, [Table 40] to [Table 43] indicate the DMRS ports used when dmrs-type=2 and maxLength=1, and [Table 44] to [Table 47] indicate the DMRS ports used when the dmrs-type is 2 and the maxLength is 2.

[0392] Regarding DCI format 0_1, if higher layer signaling dmrs-UplinkForPUSCH-MappingTypeA and dmrs-UplinkForPUSCH-MappingTypeB are both configured for the UE, the bit length of the antenna port field in DCI format 0_1 ​​may be determined as max{xA, xB}, and in this case, xA and xB may represent the bit length of the antenna port field determined by dmrs-UplinkForPUSCH-MappingTypeA and dmrs-UplinkForPUSCH-MappingTypeB, respectively. If a PUSCH mapping type corresponding to a smaller value of xA and xB is scheduled, each MSB bit whose number is equal to |xA-xB| may be assigned 0 bits and then transmitted.

[0393] Regarding DCI format 0_2, if higher layer signaling antennaPortsFieldPresenceDCI-0-2 is not configured for the UE, the antenna port field may not exist in DCI format 0_2. That is, the length of the antenna port field may be 0 bits, and the UE may determine the DMRS port by assuming the 0th entry in [Table 32] to [Table 47]. If higher layer signaling antennaPortsFieldPresenceDCI-0-2 is configured for the UE, the bit length of the antenna port field in DCI format 0_2 may be determined similarly to the case of DCI format 0_1. If both higher layer signaling dmrs-UplinkForPUSCH-MappingTypeA-DCI-0-2 and dmrs-UplinkForPUSCH-MappingTypeB-DCI-0-2 are configured for the UE, the bit length of the antenna port field in DCI format 0_2 may be determined as max{xA, xB}, and in this case, xA and xB may represent the bit length of the antenna port field determined by dmrs-UplinkForPUSCH-MappingTypeA-DCI-0-2 and dmrs-UplinkForPUSCH-MappingTypeB-DCI-0-2, respectively. If a PUSCH mapping type corresponding to a smaller value of xA and xB is scheduled, each MSB bit whose number is equal to |xA-xB| may be assigned 0 bits and then transmitted.

[0394] The numbers 1, 2, and 3 indicated by the number of DMRS CDM groups without data in [Table 32] to [Table 47] can indicate CDM groups {0}, {0, 1}, and {0, 1, 2}, respectively. The DMRS port shows the index of the port used in order. The antenna port can be indicated by DMRS port + 1000. The CDM group of DMRS is connected to the method of generating DMRS sequence and antenna port as shown in [Table 48] and [Table 49]. [Table 48] shows the parameters for the case of using dmrs-type = 1, and [Table 49] shows the parameters for the case of using dmrs-type = 2.

[0395] [Table 48]: Parameters for PUSCH DM-RS dmrs-type = 1.

[0396]

[0397] [Table 49]: Parameters for PUSCH DM-RS dmrs-type = 2.

[0398]

[0399] The DMRS sequence according to each parameter is determined by the following equation 3. In equation 3, represents the DMRS port, k represents the subcarrier index, l represents the OFDM symbol index, μ represents the subcarrier spacing, and w f (k') and w t (l') represents the frequency domain orthogonal cover code (FD-OCC) coefficient and the time domain orthogonal cover code (TD-OCC) coefficient according to the k' value and l' value, respectively, and Δ represents the interval 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 PUSCH and the EPRE of DMRS and can be expressed by to calculate, and according to the number of CDM groups 1, 2 and 3, The possible values ​​are 0dB, -3dB and -4.77 dB.

[0400] [Equation 3]

[0401]

[0402] If frequency hopping is not used, the UE may need to assume that the higher layer signaling dmrs-AdditionalPosition is configured as "pos2" and a maximum of two additional DMRS symbols can be used for PUSCH transmission. If frequency hopping is used, the UE may need to assume that the higher layer signaling dmrs-AdditionalPosition is configured as "pos1" and a maximum of one additional DMRS symbol can be used for PUSCH transmission.

[0403] In the case of PUSCH scheduled by DCI formats 0_1 and 1_2, the UE may assume that the CDM groups indicated by the column “Number of DMRS CDM groups without data” in [Table 32] to [Table 47] may include DMRS ports allocated to different UEs that can be co-scheduled by a multi-user MIMO scheme and may not be used for data transmission of the corresponding UE, and the values ​​0, 2, and 3 indicated by the column “Number of DMRS CDM groups without data” in [Table 32] to [Table 47] may be understood as the indices of the CDM groups corresponding to the described values ​​corresponding to CDM groups 0, {0, 1}, and {0, 1, 2}, respectively.

[0404] <Embodiment 1: Method for supporting enhanced DMRS types 1 and 2, wherein enhanced DMRS types 1 and 2 support an increased number of orthogonal ports>

[0405] As an embodiment of the present disclosure, a method of supporting enhanced DMRS types 1 and 2 supporting an increased number of orthogonal ports will be described.

[0406] The evolution standard of 5G 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 overhead as DMRS type 1 and DMRS type 2 already supported in the initial standard of 5G for all uplinks and downlinks. Conventional DMRS type 1 may support up to 4 and 8 orthogonal DMRS ports if the number of front-end symbols is 1 and 2, respectively, and conventional DMRS type 2 may support up to 6 and 12 orthogonal DMRS ports if the number of front-end symbols is 1 and 2, respectively.

[0407] According to the support of conventional DMRS, if the number of front-load symbols is 1 and 2, respectively, the enhanced DMRS type 1 can support up to 8 and 16 orthogonal DMRS ports, and if the number of front-load symbols is 1 and 2, respectively, the enhanced DMRS type 2 can support up to 12 and 24 orthogonal DMRS ports. In the following, the new DMRS type supporting the increased number of orthogonal ports as described above may be named one of "enhanced DMRS types 1 and 2", "new DMRS types 1 and 2", "new DMRS types 1 and 2", "DMRS types 1-1 and 2-1" or "DMRS types 3 and 4", and other similar extended names that can be used to indicate improved functions compared to the functions of conventional DMRS types 1 and 2 may not be excluded. The following items are mainly described for the downlink, but can also be similarly applied to uplink DMRS support.

[0408] If the UE supports enhanced DMRS types 1 and 2, the UE may report to the base station the UE capability of supporting enhanced DMRS types 1 and 2. The UE capability report may be sent to the base station per frequency band, and more specifically, may also be sent to the base station per feature set (FS) or per component carrier per feature set (FSPC). In addition, the UE capability report may be supported differently for each frequency range (FR) or may be limited to FR1.

[0409] In addition, as described above, the UE capability report may include the following meaning: if the number of front-load symbols is 1 and 2, respectively, the enhanced DMRS type 1 can support up to 8 and 16 orthogonal DMRS ports, and if the number of front-load symbols is 1 and 2, respectively, the enhanced DMRS type 2 can support up to 12 and 24 orthogonal DMRS ports. The UE may report enhanced DMRS types 1 and 2 through a common UE capability report, and may report whether the UE supports only enhanced DMRS type 1, only enhanced DMRS type 2, or both enhanced DMRS types 1 and 2, or may report whether the UE supports each of enhanced DMRS types 1 and 2 through separate UE capabilities.

[0410] In addition, if the UE supports the dynamic switching function between the enhanced DMRS type and the conventional DMRS type, the UE can report the function through the UE capability. The dynamic switching function between the enhanced DMRS type and the conventional DMRS type may mean that the DMRS type configured by higher layer signaling can be changed by MAC-CE, the selection between the enhanced DMRS type and the conventional DMRS type is possible through DCI, or both. If the UE reports whether it supports enhanced DMRS types 1 and 2 through common UE capabilities, the UE can report whether it supports the dynamic switching function of DMRS types 1 and 2 through one UE capability, and report whether the UE only supports dynamic switching between DMRS type 1 and enhanced DMRS type 1, the UE only supports dynamic switching between DMRS type 2 and enhanced DMRS type 2, or the UE supports dynamic switching between enhanced DMRS type and conventional DMRS type for both DMRS types. On the contrary, in the case where the UE reports whether it supports enhanced DMRS types 1 and 2 through separate UE capabilities, the UE can report that dynamic switching between conventional DMRS type and enhanced DMRS type is possible through separate UE capabilities for each DMRS type.

[0411] In the case where the UE operates with enhanced DMRS type 1 or 2, if the UE supports conventional DMRS type 1 or 2 and multi-user MIMO scheduling, the UE may report the function through UE capabilities. Multi-user MIMO scheduling may indicate co-scheduling between conventional DMRS type 1 and enhanced DMRS type 1, or co-scheduling between conventional DMRS type 2 and enhanced DMRS type 2. Similar to the above description, by reporting UE capabilities related to whether co-scheduling between conventional DMRS type and enhanced DMRS type is possible through common UE capabilities, the UE may report that co-scheduling between only conventional DMRS type 1 and enhanced DMRS type 1 is possible, co-scheduling between only conventional DMRS type 2 and enhanced DMRS type 2 is possible, or co-scheduling between conventional DMRS type and enhanced DMRS type is possible for both DMRS type 1 and DMRS type 2, or reporting may be performed through separate UE capabilities for each DMRS type.

[0412] Regarding the UE that has reported the UE capability, the base station may configure the enhanced DMRS type 1 and 2 schemes for the UE through higher layer signaling by using the following method.

[0413] -[Higher layer configuration method 1] For example, the UE may receive a configuration to support enhanced DMRS type through higher layer signaling DMRS-DownlinkConfig.

[0414] [Higher layer configuration method 1-1] A higher layer signaling dmrs-Type-r18 similar to the higher layer signaling dmrs-Type for determining the conventional DMRS type may be configured, and dmrs-Type-r18 may be used to define an enhanced DMRS type other than DMRS type 1 or 2. DMRS type 2 is used when the conventional dmrs-Type is configured, and DMRS type 1 is used when the conventional dmrs-Type is not configured. An RRC IE called dmrs-Type-r18 in addition to dmrs-Type may be newly configured in the higher layer signaling DMRS-DownlinkConfig, and through dmrs-Type-r18, one of DMRS types 1 and 2 and enhanced DMRS types 1 and 2 may be indicated, or one of enhanced DMRS types 1 and 2 may be indicated.

[0415] For example, as shown in [Table 50] below, if dmrs-Type-r18 is configured, one of DMRS type 2 and enhanced DMRS type 1 or 2 may be configured, and the existing dmrs-Type may be ignored, and if dmrs-Type-r18 is not configured, the DMRS type may be determined according to the dmrs-Type configuration scheme. For another example, if dmrs-Type-r18 is configured, one of enhanced DMRS types 1 and 2 may be configured, and the existing dmrs-Type may be ignored, and if dmrs-Type-r18 is not configured, the DMRS type may be determined according to the dmrs-Type configuration scheme. In the case of using the above-mentioned higher layer configuration method, with respect to each of PDSCH mapping types A or B, the UE may use only one of the conventional scheme (e.g., DMRS type 1 or 2) and the enhanced scheme (e.g., enhanced DMRS type 1 or 2) of the DMRS type. The scheme may be a higher layer configuration scheme in which dynamic switching between the conventional scheme and the enhanced scheme is not possible, or dynamic switching is not considered. Here, dmrs-Type-r18, which is the name of the RRC IE, is merely an example and may be different from the name of the actual RRC IE.

[0416]

Table 50

[0417]

[0418] ■[Higher layer configuration method 1-2] While maintaining the conventional meaning of the existing dmrs-Type that one of DMRS type 1 and DMRS type 2 is determined, a new RRC IE having the meaning of whether enhanced DMRS type 1 or 2 is available can be additionally configured to the UE. As shown in [Table 51] below, if the base station does not configure the higher layer signaling dmrs-Type for the UE and does not configure enhanced-Dmrs-Type-r18 for it, the UE can support the conventional scheme of DMRS type 1. In addition, if dmrs-Type is not configured for the UE and enhanced-Dmrs-Type-r18 is configured to be enabled, this may indicate that the UE can support the enhanced scheme of DMRS type 1. For example, it may mean that if dmrs-Type is configured as type 2 and enhanced-Dmrs-Type-r18 is not configured, DMRS type 2 is supported, and in this case, if dmrs-Type is configured as type 2 and enhanced-Dmrs-Type-r18 is configured, enhanced DMRS type 2 is supported. Here, in the case where the UE supports dynamic switching between conventional DMRS type and enhanced DMRS type, if enhanced-Dmrs-Type-r18 is configured for the UE, the UE can perform dynamic switching without additional higher layer signaling for dynamic switching, or can receive configuration about whether to perform dynamic switching from the base station through dynamicSwitchType as additional higher layer signaling.

[0419]

Table 51

[0420]

[0421] -[Higher layer configuration method 2] The UE may not use higher layer signaling DMRS-DownlinkConfig to support the enhanced DMRS type, and may receive the configuration supporting the enhanced DMRS type separately through a new RRC IE in PDSCH-Config. As shown in [Table 52] below, if the base station does not configure the higher layer signaling enhanced-Dmrs-Type-r18 for the UE, the UE may determine the DMRS type according to the existing DMRS-DownlinkConfig configuration. If the base station configures the higher layer signaling enhanced-Dmrs-Type-r18 for the UE, the UE may use an improved scheme of the DMRS type determined according to the existing DMRS-DownlinkConfig configuration. Here, in the case where the UE supports dynamic switching between a conventional DMRS type and an enhanced DMRS type, if enhanced-Dmrs-Type-r18 is configured for the UE, the UE may perform dynamic switching without additional higher layer signaling for dynamic switching, or may receive a configuration regarding whether to perform dynamic switching from the base station through dynamicSwitchType as additional higher layer signaling.

[0422]

Table 52

[0423]

[0424] Hereinafter, various supporting methods for determining specific RE mapping and OCC for enhanced DMRS types 1 and 2 will be described.

[0425] [Enhanced DMRS Type 1 Support Method 1]

[0426] As an embodiment of a method supporting the above-mentioned enhanced DMRS type 1, the time and frequency resource mapping of DMRS RE and its FD-OCC and TD-OCC coefficients may be determined based on the following [Equation 4] and [Table 53] when using enhanced DMRS type 1.

[0427] [Equation 4]

[0428]

[0429] [Table 53]: Parameters for [Enhanced DMRS Type 1 Support Method 1]

[0430]

[0431] In [Enhanced DMRS Type 1 Support Method 1] based on the above [Equation 4] and [Table 53], a total of four CDM groups are used. In the case of one frontload DMRS symbol, two DMRS ports can be included in each CDM group, and thus the enhanced DMRS type 1 can support a total of eight orthogonal DMRS ports, and in the case of two frontload DMRS symbols, four DMRS ports can be included in each CDM group, and thus the enhanced DMRS type 1 can support a total of 16 orthogonal DMRS ports. Compared to the spacing between REs allocated to a specific DMRS port in the same CDM group being two REs in conventional DMRS type 1, the enhanced DMRS type 1 supports four CDM groups, and thus the spacing can be increased to four REs. According to Method 1, the number of CDM groups is increased while maintaining the number of DMRS ports in each CDM group, and thus the scheduling of the PDSCH to be transmitted together with the 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 to calculate, and according to the number of CDM groups 1, 2, 3 and 4, The possible values ​​are 0dB, -3dB, -4.77 dB and -6dB.

[0432] [Enhanced DMRS Type 1 Support Method 2]

[0433] As another embodiment of a method supporting the above-mentioned enhanced DMRS type 1, the time and frequency resource mapping of DMRS RE and its FD-OCC and TD-OCC coefficients may be determined based on the following [Equation 5] and [Table 54] when using enhanced DMRS type 1.

[0434] [Equation 5]

[0435]

[0436] [Table 54]: Parameters for [Enhanced DMRS Type 1 Support Method 2]

[0437]

[0438] In [Enhanced DMRS Type 1 Support Method 2] based on [Equation 5] and [Table 54] 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, and thus the enhanced DMRS type 1 can support a total of eight orthogonal DMRS ports, and in the case of two front-loaded DMRS symbols, four DMRS ports can be included in each CDM group, and thus the enhanced DMRS type 1 can support a total of 16 orthogonal DMRS ports. The number of CDM groups is increased while maintaining the number of DMRS ports in each CDM group, and thus the scheduling of the PDSCH to be transmitted with the DMRS can be limited to two RBs.

[0439] According to method 2, as in conventional DMRS type 1, the interval between REs allocated to a specific DMRS port in the same CDM group is maintained as two REs, but there may be a case where, for each DMRS port, the DMRS density of a specific RB among two RBs is high and the DMRS density of the other RB is low. For example, in the case of DMRS ports 1000 to 1003 (or in the case of CDM groups 0 and 1), 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 (or in the case of CDM groups 2 and 3), the opposite may occur. In equation 5, is a scaling factor indicating the ratio between the 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, 3 and 4, The possible values ​​are 0dB, -3dB, -4.77 dB and -6dB.

[0440] [Enhanced DMRS Type 1 Support Method 3]

[0441] As another embodiment of the method supporting the above-mentioned enhanced DMRS type 1, the time and frequency resource mapping of DMRS RE and its FD-OCC and TD-OCC coefficients can be determined based on the above [Equation 2] and the following [Table 55] when using enhanced DMRS type 1.

[0442] The difference between conventional DMRS type 1 and method 3 is as follows. According to method 3, if the number of front-end symbols is 1, indication of DMRS ports 1000 to 1003 for even-numbered RBs in which PDSCH is scheduled (or allocation of DMRS ports 1000 to 1003) may be possible, and indication of DMRS ports 1004 to 1007 for odd-numbered RBs (or allocation of DMRS ports 1004 to 1007) may be possible. If the number of front-end symbols is 2, indication of DMRS ports 1000 to 1007 for even-numbered RBs in which PDSCH is scheduled is possible, and indication of DMRS ports 1008 to 1015 for odd-numbered RBs is possible. Therefore, as shown in [Table 55] below, when the indices of the DMRS ports differ from each other by eight indices, the FD-OCC coefficient and the TD-OCC coefficient may be the same. Alternatively, although the indication of only DMRS ports 1000 to 1007 is supported by using the above [Table 30], the base station can use a method by which, even for the same DMRS port 1000, by additionally indicating whether the DMRS RE is set in an even-numbered RB or an odd-numbered RB in the frequency resource where the PDSCH is scheduled, the DMRS port is distinguished according to the RB in which the DMRS RE is set. The detailed DMRS port indication and RB position indication method will be described later.

[0443] [Table 55] Parameters for [Enhanced DMRS Type 1 Support Method 3]

[0444]

[0445] In [Enhanced DMRS Type 1 Support Method 3] based on [Equation 2] and [Table 55] above, a total of two CDM groups are used. In the case of one front-loaded DMRS symbol, two DMRS ports may be included in each CDM group and the DMRS ports are divided to be allocated to even-numbered RBs and odd-numbered RBs, and thus enhanced DMRS Type 1 may support a total of eight orthogonal DMRS ports, and in the case of two front-loaded DMRS symbols, four DMRS ports may be included in each CDM group and thus DMRS Type 1 may support a total of 16 orthogonal DMRS ports. According to Method 3, DMRS is divided to be allocated to even-numbered RBs and odd-numbered RBs while maintaining the number of DMRS ports in each CDM group and the number of CDM groups, and thus scheduling of PDSCH to be transmitted together with DMRS may be limited to units of three or more RBs.

[0446] [Enhanced DMRS Type 2 Support Method 1]

[0447] As an embodiment of a method supporting the above-mentioned enhanced DMRS type 2, the time and frequency resource mapping of DMRS RE and its FD-OCC and TD-OCC coefficients may be determined based on the following [Equation 6] and [Table 56] when using enhanced DMRS type 2.

[0448] [Equation 6]

[0449]

[0450] [Table 56]: Parameters for [Enhanced DMRS Type 2 Support Method 1]

[0451]

[0452] In [Enhanced DMRS Type 2 Support Method 1] based on [Equation 6] and [Table 56] 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, and thus the enhanced DMRS type 2 can support a total of 12 orthogonal DMRS ports, and in the case of two front-loaded DMRS symbols, eight DMRS ports can be included in each CDM group, and thus the enhanced DMRS type 2 can support a total of 24 orthogonal DMRS ports.

[0453] According to method 1, the number of DMRS ports in each CDM group increases while the number of CDM groups is maintained, and thus the scheduling of the PDSCH to be transmitted together with the DMRS can be maintained to a unit of one RB in the same manner as the conventional unit. However, the positions of the DMRS REs are concentrated in a specific position in the RB, and thus when scheduling PDSCHs for two or more RBs, the DMRS channel estimation performance can be ensured. For example, the RE positions in the RB for DMRS ports 1000 to 1003 in CDM group #0 are arranged on the 0th to 4th subcarriers, and thus the DMRS is concentrated only on the subcarriers with low indexes in the RB, and in this case, the DMRS channel estimation performance of the subcarriers with high indexes may be degraded. In Equation 6, is a scaling factor indicating the ratio between the 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, The possible values ​​are 0dB, -3dB and -4.77 dB.

[0454] [Enhanced DMRS Type 2 Support Method 2]

[0455] As another embodiment of a method for supporting the above-mentioned enhanced DMRS type 2, the time and frequency resource mapping of DMRS RE and its FD-OCC and TD-OCC coefficients can be determined based on the above [Equation 2] and the following [Table 57] when using enhanced DMRS type 2. Here, the difference between conventional DMRS type 2 and enhanced DMRS type 2 is that an indication of DMRS ports 1000 to 1011 (or an allocation of DMRS ports 1000 to 1011) for even-numbered RBs in which PDSCH is scheduled is possible, and an indication of DMRS ports 1012 to 1023 (or an allocation of DMRS ports 1012 to 1023) for odd-numbered RBs is possible. This is similar to [Enhanced DMRS Type 1 Support Method 3]. Therefore, as shown in the following [Table 57], when the indices of the DMRS ports differ from each other by 12 indices, the FD-OCC coefficient and the TD-OCC coefficient can be the same. Alternatively, although the indication of only DMRS ports 1000 to 1011 is supported by using the above-mentioned [Table 31], the base station can use a method by which, even for the same DMRS port 1000, by additionally indicating whether the DMRS RE is set in an even-numbered RB or an odd-numbered RB in the frequency resource where the PDSCH is scheduled, the DMRS port is distinguished according to the RB in which the DMRS RE is set. The detailed DMRS port indication and RB position indication method will be described later.

[0456] [Table 57] Parameters for [Enhanced DMRS Type 2 Support Method 2]

[0457]

[0458] In [Enhanced DMRS Type 2 Support Method 2] based on the above [Equation 2] and [Table 57], a total of three CDM groups are used. In the case of one front-loaded DMRS symbol, two DMRS ports may be included in each CDM group and the DMRS ports are divided to be allocated to even-numbered RBs and odd-numbered RBs, and thus the enhanced DMRS type 2 may support a total of 12 orthogonal DMRS ports, and in the case of two front-loaded DMRS symbols, four DMRS ports may be included in each CDM group and thus the DMRS type 2 may support a total of 24 orthogonal DMRS ports. The DMRS is divided to be allocated to even-numbered RBs and odd-numbered RBs while maintaining the number of DMRS ports in each CDM group and the number of CDM groups, and thus the scheduling of the PDSCH to be transmitted together with the DMRS may be limited to units of three or more RBs.

[0459] <Embodiment 1-1: Method for additionally supporting enhanced DMRS types 1 and 2, wherein enhanced DMRS types 1 and 2 support an increased number of orthogonal ports>

[0460] As an embodiment of the present disclosure, in addition to the [Enhanced DMRS Type 1 Support Method 1], [Enhanced DMRS Type 1 Support Method 2], [Enhanced DMRS Type 1 Support Method 3], [Enhanced DMRS Type 2 Support Method 1] and [Enhanced DMRS Type 2 Support Method 2] in the above-mentioned Embodiment 1, a method for additionally supporting enhanced DMRS Types 1 and 2 will also be described, which enhance DMRS Types 1 and 2 support an additional increased number of orthogonal ports.

[0461] [Enhanced DMRS Type 1 Support Method 4]

[0462] As another embodiment of a method supporting the above-mentioned enhanced DMRS type 1, the time and frequency resource mapping of DMRS RE and its FD-OCC and TD-OCC coefficients may be determined based on the following [Equation 7] and [Table 58] when using enhanced DMRS type 1.

[0463] [Equation 7]

[0464]

[0465] [Table 58] Parameters for [Enhanced DMRS Type 1 Support Method 4]

[0466]

[0467] In [Enhanced DMRS Type 1 Support Method 4] based on [Equation 7] and [Table 58] 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, and thus enhanced DMRS Type 1 can support a total of 16 orthogonal DMRS ports.

[0468] According to [Enhanced DMRS Type 1 Support Method 4], since the number of DMRS ports in a CDM group is increased while being maintained at two, the number of CDM groups of conventional DMRS type 1, the scheduling of PDSCH to be transmitted together with DMRS can be maintained in units of one RB as in the conventional unit, and DMRS can be mapped to the same RE position as that of conventional DMRS type 1. However, in the case of using conventional DMRS type 1, under the assumption that channels of two REs (e.g., RE#0 and RE#2) at positions spaced 2 REs apart from each other are the same, the receiver has applied OCC to the two REs to distinguish 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 have been used.

[0469] Based on [Enhanced DMRS Type 1 Support Method 4], in the case of one front-loaded DMRS symbol, a total of six REs in one RB are used per port, and the receiver can distinguish a total of four orthogonal ports by using one OCC of length 6. Here, an OCC of length 6 is applied to six REs, and the REs may exist at positions spaced two REs apart from each other (ie, the subcarrier index difference of each RE is 2). That is, the receiver can apply the OCC by assuming that six REs with relative RE positions of 0, 2, 4, 6, 8, and 10 belong to the same channel, and thus the channel estimation performance may be degraded compared to conventional DMRS Type 1. Therefore, this enhanced DMRS Type 1 can be used for multi-user MIMO in a channel with small frequency selectivity characteristics.

[0470] In the above [Table 58], the values ​​of A, B, and C in the OCC having a length of 6 are determined to give orthogonality between all ports, and for example, A=1, B= and C = is possible, but other values ​​are not excluded. Thus, the value of A, B or C may be pre-defined in the standard to be specified between the UE and the base station, may be configured for the UE through higher layer signaling, may be activated to the UE through MAC-CE, may be dynamically indicated to the UE through DCI, or may be notified to the UE through a combination of these signaling. In the above [Equation 7], is a scaling factor indicating the ratio between the 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, The possible values ​​are 0dB and -3dB.

[0471] [Enhanced DMRS Type 1 Support Method 5]

[0472] As another embodiment of a method supporting the above-mentioned enhanced DMRS type 1, the time and frequency resource mapping of DMRS RE and its FD-OCC and TD-OCC coefficients may be determined based on the following [Equation 8] and [Table 59] when using enhanced DMRS type 1.

[0473] [Equation 8]

[0474]

[0475] [Table 59] Parameters for [Enhanced DMRS Type 1 Support Method 5]

[0476]

[0477] In [Enhanced DMRS Type 1 Support Method 5] based on the above [Equation 8] and [Table 59], 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, and thus enhanced DMRS type 1 can support a total of 16 orthogonal DMRS ports. Since the number of DMRS ports in the CDM group is increased while maintaining two, the number of CDM groups of conventional DMRS type 1, the scheduling of PDSCH to be transmitted with DMRS can be maintained in units of one RB the same as the conventional unit, and DMRS can be mapped to the same RE position as the RE position of conventional DMRS type 1. However, in the case of using conventional DMRS type 1, under the assumption that the channels of two REs (e.g., RE#0 and RE#2) at positions spaced 2 REs apart from each other are the same, the receiver has applied OCC to the two REs to distinguish 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 have been used.

[0478] Based on [Enhanced DMRS Type 1 Support Method 5], in the case of one front-loaded DMRS symbol, a total of six REs in one RB are used per port, and the receiver can distinguish a total of four orthogonal ports by using one OCC with a length of 6. Here, an OCC with a length of 6 is applied to six REs, and the REs may exist at positions spaced two REs apart from each other (ie, the subcarrier index difference of each RE is 2). That is, the receiver can apply the OCC by assuming that six REs with relative RE positions of 0, 2, 4, 6, 8, and 10 belong to the same channel, and thus the channel estimation performance may be degraded compared to conventional DMRS Type 1. Therefore, the enhanced DMRS Type 1 can be used for multi-user MIMO in a channel with a small frequency selectivity characteristic.

[0479] In the above [Table 59], the values ​​of A, B, and C in the OCC having a length of 6 are determined to give orthogonality between all ports, and for example, A=1, B= and C = It is possible, but other values ​​are not excluded. Thus, the value of A, B or C can be pre-defined in the standard to be specified between the UE and the base station, can be configured for the UE through higher layer signaling, can be activated to the UE through MAC-CE, can be dynamically indicated to the UE through DCI, or can be notified to the UE through a combination of these signaling. In the above [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, The possible values ​​are 0dB and -3dB.

[0480] [Enhanced DMRS Type 1 Support Method 6]

[0481] As another embodiment of a method supporting the above-mentioned enhanced DMRS type 1, the time and frequency resource mapping of DMRS RE and its FD-OCC and TD-OCC coefficients may be determined based on the following [Equation 9] and [Table 60] when using enhanced DMRS type 1.

[0482] [Equation 9]

[0483]

[0484] [Table 60] Parameters for [Enhanced DMRS Type 1 Support Method 6]

[0485]

[0486] In [Enhanced DMRS Type 1 Support Method 6] based on the above [Equation 9] and [Table 60], 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 thus the enhanced DMRS type 1 can support up to eight orthogonal DMRS ports, and in the case of two front-loaded DMRS symbols, eight DMRS ports can be included in each CDM group, and thus the enhanced DMRS type 1 can support a total of 16 orthogonal DMRS ports. Since the number of DMRS ports in the CDM group is increased while maintaining two, the number of CDM groups of the conventional DMRS type 1, and the OCC length is thus increased to 4, the scheduling of the PDSCH transmitted together with the DMRS can be in units of two RBs and the DMRS can be mapped to the same RE position as the RE position of the conventional DMRS type 1. However, in the case of using conventional DMRS type 1, under the assumption that the channels of two REs (e.g., RE#0 and RE#2) at positions spaced 2 REs apart from each other are the same, the receiver has applied OCC to the two REs to distinguish orthogonal ports, and in the case of one front-loaded DMRS symbol, each port uses a total of six REs in one RB, and three OCCs of length 2 have been used.

[0487] Based on [Enhanced DMRS Type 1 Support Method 6], in the case of one front-loaded DMRS symbol, a total of 12 REs in two RBs are used per port, and the receiver can distinguish a total of four orthogonal antenna ports by using an OCC of length 4 applied to four adjacent REs. Here, an OCC with a length of 4 is applied to four REs, and the four REs may exist at positions spaced two REs apart from each other (ie, the subcarrier index difference between REs is 2). That is, the receiver can apply the OCC by assuming that four REs with relative RE positions of 0, 2, 4, and 6 belong to the same channel, and thus the channel estimation performance may be degraded compared to conventional DMRS Type 1. Therefore, this enhanced DMRS Type 1 can be used for multi-user MIMO in a channel with small frequency selectivity characteristics.

[0488] In the above [Table 60], w of ports 1000 to 1015 among OCCs having a length of 4 f The (k') value is determined to give orthogonality between all ports, and the values ​​in the above table do not exclude other values ​​as examples. In [Equation 9] above, is a scaling factor indicating the ratio between the 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, The possible values ​​are 0dB and -3dB.

[0489] [Enhanced DMRS Type 2 Support Method 3]

[0490] In case of using enhanced DMRS type 2 based on the following [Equation 10] and [Table 61], time and frequency resource mapping of DMRS RE and its FD-OCC and TD-OCC coefficients may be determined.

[0491] [Equation 10]

[0492]

[0493] [Table 61]: Parameters for [Enhanced DMRS Type 2 Support Method 3]

[0494]

[0495] In [Enhanced DMRS Type 10 Support Method 2] based on [Equation 3] and [Table 61] 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, and thus the enhanced DMRS type 2 can support a total of 12 orthogonal DMRS ports, and in the case of two front-loaded DMRS symbols, eight DMRS ports can be included in each CDM group, and thus the enhanced DMRS type 2 can support a total of 24 orthogonal DMRS ports. Since the number of DMRS ports in the CDM group is increased while maintaining the number of CDM groups, the scheduling of the PDSCH transmitted together with the DMRS can be maintained in units of one RB the same as the conventional unit, and the DMRS can be mapped to the same RE position as the RE position of 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 two REs to distinguish 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 with a length of 2 are used.

[0496] Based on [Enhanced DMRS Type 2 Support Method 3], in the case of one front-loaded DMRS symbol, a total of six REs in one RB are used per port, and the receiver can distinguish a total of four orthogonal ports by using one OCC with a length of 4. Here, an OCC with a length of 4 is applied to two consecutive RE sets spaced 6 REs apart from each other (i.e., the subcarrier index difference between REs is 6), i.e., the receiver can apply the OCC by assuming that four REs with relative RE positions of 0, 1, 6, and 7 belong to the same channel, and thus the channel estimation performance may be degraded compared to the conventional DMRS Type 2. Therefore, the enhanced DMRS Type 2 can be used for multi-user MIMO in a channel with a small frequency selectivity characteristic.

[0497] In equation 10, is a scaling factor indicating the ratio between the 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, The possible values ​​are 0dB, -3dB and -4.77 dB.

[0498] [Enhanced DMRS Type 2 Support Method 4]

[0499] In case of using enhanced DMRS type 2 based on the following [Equation 11] and [Table 62] or [Table 63], time and frequency resource mapping of DMRS RE and its FD-OCC and TD-OCC coefficients may be determined.

[0500] [Equation 11]

[0501]

[0502] [Table 62]: Parameters for [Enhanced DMRS Type 2 Support Method 4]

[0503]

[0504] [Table 63]: Parameters for [Enhanced DMRS Type 2 Support Method 4]

[0505]

[0506] In [Enhanced DMRS type 2 support method 4] based on [Equation 11] and [Table 62] or [Table 63], a total of six CDM groups are used, and in the case of one front-loaded DMRS symbol, two DMRS ports can be included in each CDM group, and thus the enhanced DMRS type 2 can support a total of 12 orthogonal DMRS ports, and in the case of two front-loaded DMRS symbols, four DMRS ports can be included in each CDM group, and thus the enhanced DMRS type 2 can support a total of 24 orthogonal DMRS ports. Since the number of CDM groups is increased while maintaining the number of DMRS ports in the CDM group, scheduling of the PDSCH transmitted together with the DMRS can be maintained in units of one RB as the same as the conventional unit, and the DMRS can be mapped to some RE positions of the RE positions of the conventional DMRS type 2.

[0507] However, although the receiver estimates the channel by using a total of four REs in one RB when using the conventional DMRS type 2, when based on [enhanced DMRS type 2 support method 4], the receiver can use a total of two REs that are half of the conventional DMRS type 2 in one RB per port, and distinguish a total of two orthogonal ports by using one OCC having a length of 2. Here, only two DMRS REs are used in one RB, and thus the channel estimation performance may be degraded compared to the conventional DMRS type 2. Therefore, the enhanced DMRS type 2 can be used for multi-user MIMO in a channel with a small frequency selectivity characteristic.

[0508] In Equation 11, is a scaling factor indicating the ratio between the 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, 3, 4, 5 and 6, The value of may be 0dB, -3dB, -4.77dB, -6dB, -6.99dB, and -7.7dB. Here, in the case where the number of CDM groups exceeds a predetermined number (eg, four or more), The value of may be limited to a predetermined upper limit value. Here, the predetermined number of CDM groups and the corresponding The predetermined upper limit value can be configured from the base station to the UE through higher layer signaling, activated through MAC-CE signaling, indicated through L1 signaling, notified through a combination of higher layer signaling and L1 signaling, or fixedly defined in the standard.

[0509] Regarding [Enhanced DMRS Type 1 Support Method 1] to [Enhanced DMRS Type 1 Support Method 6] and [Enhanced DMRS Type 2 Support Method 1] to [Enhanced DMRS Type 2 Support Method 4], the UE may report to the base station a UE capability indicating that each support method is possible. The corresponding UE capability may be valid for FR1 or for both FR1 and FR2. The corresponding UE capability may include an indication of the maximum number of supported DMRS antenna ports, which, regarding enhanced DMRS Type 1, is 8 when one front-loaded DMRS symbol is used and 16 when two front-loaded DMRS symbols are used, and regarding enhanced DMRS Type 2, is 12 when one front-loaded DMRS symbol is used and 24 when two front-loaded DMRS symbols are used. After receiving the UE capability, the base station may configure a higher layer signaling corresponding thereto and the higher layer signaling may correspond to one of the above methods or an independent higher layer signaling.

[0510] The base station and the UE may support at least one of the support methods mentioned in the above-mentioned embodiment 1 ([enhanced DMRS type 1 support method 1], [enhanced DMRS type 1 support method 2], [enhanced DMRS type 1 support method 3], [enhanced DMRS type 2 support method 1], or [enhanced DMRS type 2 support method 2]) and the additional support methods for enhanced DMRS types 1 and 2 described in the embodiments ([enhanced DMRS type 1 support method 4], [enhanced DMRS type 1 support method 5], [enhanced DMRS type 1 support method 6], [enhanced DMRS type 2 support method 3], or [enhanced DMRS type 2 support method 4]) by using configuration of higher layer signaling, indication based on L1 signaling, a combination of higher layer signaling and L1 signaling, or a method fixedly specified in the standard.

[0511] The above-mentioned [Equation 4] to [Equation 11] and [Table 53] to [Table 63] can also be modified and applied in an obvious manner without impairing the spirit of the present disclosure.

[0512] <Example 2: Orthogonal Cover Code Deactivation Method When Supporting Enhanced DMRS Types 1 and 2>

[0513] As an embodiment of the present disclosure, a method for deactivating orthogonal cover codes during support of enhanced DMRS types 1 and 2, which can be notified to the UE from the base station through the above embodiment. The UE can receive signaling for deactivating the orthogonal cover code applied to the DMRS RE from the base station under predetermined circumstances. In this case, the base station can support the deactivation of the orthogonal cover code by using a configuration method through higher layer signaling, an indication method based on L1 signaling, a combination method of higher layer and L1 signaling, or a method fixedly specified in the standard. The aforementioned signaling from the base station can be notified to the UE by a combination of at least one of the following [Method 2-1] to [Method 2-3].

[0514] [Method 2-1]

[0515] In the case where the UE receives the configuration of higher layer signaling from the base station and is scheduled for rank 1 PDSCH, the orthogonal cover code used when receiving the PDSCH can be deactivated. In the case where the UE receives the configuration of higher layer signaling from the base station and is scheduled for PDSCH through DCI format 1_1 or 1_2, and in the case where the number of DMRS ports of the antenna port field indicated by the corresponding DCI format is 1 (that is, the PDSCH including a single layer is scheduled), the UE can assume that another DMRS port orthogonal to the corresponding DMRS port in the CDM group including the corresponding DMRS port is not scheduled for another UE. That is, the UE can assume that only the corresponding DMRS port is scheduled between all UEs in the CDM group including the corresponding DMRS port, and other DMRS ports orthogonal to the corresponding DMRS port are not used. Therefore, when receiving the corresponding DMRS port, the UE can use each RE for channel estimation without applying an orthogonal cover code with respect to multiple REs. Therefore, the UE can expect improved channel estimation performance using each DMRS RE without separating different DMRS ports using multiple RE spatial multiplexing.

[0516] [Method 2-2]

[0517] In the case where the UE receives configuration of higher layer signaling from the base station and is scheduled for rank 1 PDSCH by using DMRS ports within a specific CDM group for the UE from the base station, the orthogonal cover code used when receiving the PDSCH can be deactivated. In the case where the UE receives configuration of higher layer signaling from the base station and is scheduled for PDSCH through DCI format 1_1 or 1_2, in the case where the number of DMRS ports of the antenna port field indicated by the corresponding DCI format is 1 (i.e., a PDSCH including a single layer is scheduled), and in the case where the corresponding DMRS port is included in a specific CDM group, the UE can assume that other DMRS ports orthogonal to the corresponding DMRS port within the CDM group including the corresponding DMRS port are not scheduled for other UEs.

[0518] The base station may use one or more predetermined CDM groups among the CDM groups available to the UE for the purpose of channel estimation, and may use the remaining one or more CDM groups for spatial multiplexing with another UE. In this case, the base station may notify the UE of the one or more predetermined CDM groups by using a configuration method through higher layer signaling, an indication method based on L1 signaling, a combination method of higher layer and L1 signaling, or a method fixedly specified in the standard.

[0519] As an example, if the base station uses a configuration method through higher layer signaling, then when the base station configures, for example, CDM group #0 for the UE and if the UE is instructed to use the DMRS port within the corresponding CDM group, the base station can notify the deactivation of the orthogonal cover code to be applied to the corresponding DMRS port. That is, the UE can assume that other DMRS ports orthogonal to the corresponding DMRS port within the CDM group including the corresponding DMRS port are not scheduled for other UEs. As an example, in the case where the base station uses an indication method based on L1 signaling, the base station can indicate to the UE the deactivation of the orthogonal cover code for a predetermined CDM group through the antenna port field in DCI format 1_1 or 1_2, or dynamically indicate to the UE through a field newly defined for the corresponding function.

[0520] As an example, a case where the base station uses a combination method of higher layer signaling and L1 signaling will be described. The base station can notify the UE of configuration information indicating turning on or off the orthogonal cover code deactivation function through higher layer signaling, and when the UE receives the configuration of turning on the corresponding higher layer signaling and the indication of deactivation of the orthogonal cover code of the predetermined CDM group through the antenna port field or the new field in the DCI format 1_1 or 1_2, the UE can assume that the orthogonal cover code of the DMRS port in the corresponding CDM group is deactivated.

[0521] As an example, a case where the base station uses another combination method of higher layer signaling and L1 signaling will be described. The base station may notify the UE of configuration information indicating which CDM groups are used for orthogonal cover code deactivation through higher layer signaling, and in the case where the corresponding higher layer signaling is configured as CDM group #0 and the DMRS port within CDM group #0 is indicated by the antenna port field in DCI format 1_1 or 1_2, the UE may assume that the orthogonal cover code is deactivated when receiving the DMRS port within the corresponding CDM group. That is, the UE may assume that only the corresponding DMRS port is scheduled between all UEs in the CDM group including the corresponding DMRS port and that other DMRS ports orthogonal to the corresponding DMRS port are not used. Therefore, when receiving the corresponding DMRS port, the UE may use each RE for channel estimation without applying an orthogonal cover code with respect to multiple REs. Therefore, the UE may expect improved channel estimation performance using each DMRS RE without separating different DMRS ports using multiple RE spatial multiplexing.

[0522] [Method 2-3]

[0523] In the case where the UE receives a configuration of higher layer signaling from the base station and is scheduled for rank 1 PDSCH by using one of one or more predetermined DMRS ports, the orthogonal cover code used when receiving the PDSCH can be deactivated. In the case where the UE receives a configuration of higher layer signaling from the base station and is scheduled for PDSCH by DCI format 1_1 or 1_2, in the case where the number of DMRS ports of the antenna port field indicated by the corresponding DCI format is 1 (i.e., a PDSCH including a single layer is scheduled), and in the case where one DMRS port among the one or more predetermined DMRS ports is indicated, the UE can assume that other DMRS ports orthogonal to the corresponding DMRS port within the CDM group including the corresponding DMRS port are not scheduled for other UEs.

[0524] The base station may use one or more predetermined DMRS ports among a plurality of DMRS ports available to the UE for the purpose of channel estimation, and may use the remaining one or more DMRS ports for spatial multiplexing with another UE. In this case, the base station may notify the UE of information about one or more predetermined DMRS ports to be used for the purpose of channel estimation performance improvement by using a configuration method through higher layer signaling, using an indication method based on L1 signaling, using a combination method of higher layer and L1 signaling, or using a method fixedly specified in the standard.

[0525] As an example, if the base station uses a configuration method through higher layer signaling, then in the case where the base station configures, for example, DMRS ports #0 and #2 for the UE, and if the UE is instructed to use one of the corresponding DMRS ports, the base station can notify the UE to deactivate the orthogonal cover code to be applied to the corresponding DMRS port. That is, the UE can assume that other DMRS ports orthogonal to the corresponding DMRS port within the CDM group including the corresponding DMRS port are not scheduled for other UEs. As an example, a case where the base station uses an indication method based on L1 signaling will be described. The base station can indicate to the UE the deactivation of the orthogonal cover code for a predetermined DMRS port through the antenna port field in DCI format 1_1 or 1_2 or dynamically indicate to the UE through a field newly defined for the corresponding function.

[0526] As an example, a case where the base station uses a combination method of higher layer signaling and L1 signaling will be described. The base station can notify the UE of configuration information indicating turning on or off the orthogonal cover code deactivation function through higher layer signaling, and when the UE receives the configuration of turning on the corresponding higher layer signaling and the indication of deactivation of the orthogonal cover code for one of the one or more predetermined DMRS ports through the antenna port field or the new field in the DCI format 1_1 or 1_2, the UE can assume that the orthogonal cover code for the indicated DMRS port within the corresponding CDM group is deactivated.

[0527] As an example, a case where the base station uses another combined method of higher layer signaling and L1 signaling will be described. The base station may notify the UE of configuration information indicating which DMRS ports are used for orthogonal cover code deactivation through higher layer signaling, and in the case where the corresponding higher layer signaling is configured as DMRS port 0 or 2 and one of DMRS ports 0 or 2 is indicated through the antenna port field in DCI format 1_1 or 1_2, the UE may assume that the orthogonal cover code is deactivated when receiving the DMRS port. That is, the UE may assume that only the corresponding DMRS port is scheduled among all UEs within the CDM group including the corresponding DMRS port and other DMRS ports orthogonal to the corresponding DMRS port are not used, and therefore the UE may use each RE for channel estimation when receiving the corresponding DMRS port without applying an orthogonal cover code with respect to multiple REs. Therefore, the UE may expect improved channel estimation performance using each DMRS RE without separating different DMRS ports using multiple RE spatial multiplexing.

[0528] The UE may report the functions corresponding to the above-mentioned [Method 2-1] to [Method 2-3] to the base station as UE capabilities. Here, the functions that may be included in the UE capabilities may include at least one combination of the following.

[0529] In addition, the corresponding UE capability report may be valid for FR1 or for both FR1 and FR2. The corresponding UE capabilities may be reported with different values ​​for each frequency band, frequency band combination, feature set, feature set per CC, and per UE. Different values ​​may be reported according to the frequency band combination. After receiving the UE capabilities, the base station may configure higher layer signaling corresponding thereto and the higher layer signaling may correspond to one of the above methods or independent higher layer signaling.

[0530] Fig.18 An example of operation of a UE for activating a DMRS orthogonal cover code according to an embodiment of the present disclosure is shown.

[0531] The UE may send the above-mentioned UE capabilities to the base station (1800). Here, the reportable UE capabilities may correspond to UE capabilities for supporting enhanced DMRS types 1 and 2 as described above, UE capabilities for supporting or not supporting the methods mentioned in the above-mentioned embodiments, separate UE capabilities for PDSCH and PUSCH, or integrated UE capabilities. Thereafter, the UE may receive information about enhanced DMRS type 1 or 2 from the base station (1810). In this case, the information about enhanced DMRS type 1 or 2 may include a notification of the methods mentioned in the above-mentioned embodiments for the UE from the base station (which may be based on independent higher layer signaling, based on higher layer signaling for the above-mentioned enhanced DMRS types 1 and 2, based on MAC-CE activation or deactivation, or dynamically indicated by PDCCH).

[0532] Thereafter, the UE may receive PDSCH scheduling information (1820) to which enhanced DMRS type 1 or 2 is applied from the base station. Here, in the case of PDSCH, the corresponding scheduling information may be indicated by DCI format 1_1 or 1_2, and the corresponding scheduling information may be indicated by using an antenna field and / or a new field related to orthogonal cover code deactivation, depending on which of the methods mentioned in the above embodiments. In this case, if the conditions (1830) required by [Method 2-1] to [Method 2-3] are met, the UE may receive PDSCH (1840) by using the first DMRS reception method. Meeting the above-mentioned required conditions may correspond to a case where, for example, according to [Method 2-3], the UE receives a configuration of information about deactivating an orthogonal cover code when using DMRS port 0 through higher layer signaling from the base station, and receives an indication of DMRS port 0 through an antenna port field included in DCI format 1_1 or 1_2, otherwise the above-mentioned necessary conditions are not met, and the UE may receive PDSCH (1850) by using the second DMRS reception method.

[0533] As a first DMRS reception method, the UE may deactivate an orthogonal cover code with respect to the indicated DMRS port and receive the PDSCH by using each of a plurality of DMRS REs without applying an orthogonal cover code to be used for channel estimation, nor by using a plurality of DMDS REs and applying an orthogonal cover code for channel estimation (1850). That is, the UE may assume that other DMRS ports orthogonal to the corresponding DMRS port within the CDM group including the corresponding DMRS port are not scheduled for other UEs. As a second DMRS reception method, the UE may activate an orthogonal cover code with respect to the indicated DMRS port and receive the PDSCH by using a plurality of DMRS REs and applying an orthogonal cover code for channel estimation (1840).

[0534] The above-described operations are merely examples, not all operations are essential, and one of the operations may not be performed, the order may be changed or omitted, or other operations may be added.

[0535] Fig.19 An example of the operation of a base station for deactivating a DMRS orthogonal cover code according to an embodiment of the present disclosure is shown.

[0536] The base station may receive the above-mentioned UE capabilities from the UE (1900). Here, the reportable UE capabilities may correspond to UE capabilities for supporting enhanced DMRS types 1 and 2 as described above, UE capabilities for supporting or not supporting the methods mentioned in the above-mentioned embodiments, separate UE capabilities for PDSCH and PUSCH, or integrated UE capabilities. Thereafter, the base station may send information about enhanced DMRS type 1 or 2 to the UE (1910). In this case, the information about enhanced DMRS type 1 or 2 may include a notification of the methods mentioned in the above-mentioned embodiments for the UE from the base station (which may be based on independent higher layer signaling, based on higher layer signaling for the above-mentioned enhanced DMRS types 1 and 2, based on MAC-CE activation or deactivation, or dynamically indicated by PDCCH).

[0537] Thereafter, the base station may transmit PDSCH scheduling information (1920) to which enhanced DMRS type 1 or 2 is applied to the UE. Here, in the case of PDSCH, the corresponding scheduling information may be indicated by DCI format 1_1 or 1_2, and the corresponding scheduling information may be indicated by using an antenna field and / or a new field related to orthogonal cover code deactivation, depending on which of the methods mentioned in the above embodiments. In this case, if the conditions (1930) required by [Method 2-1] to [Method 2-3] are met, the base station may transmit the PDSCH (1940) assuming that the PDSCH is received by using the first DMRS reception method. Meeting the above-mentioned required conditions may correspond to a case where, for example, according to [Method 2-3], the base station configures information about deactivating the orthogonal cover code when using DMRS port 0 to the UE through higher layer signaling and indicates DMRS port 0 through the antenna port field included in DCI format 1_1 or 1_2. Otherwise, it may mean that the above-mentioned necessary conditions are not met, and the base station may transmit the PDSCH (1950) assuming that the PDSCH is received by using the second DMRS reception method.

[0538] When the first DMRS reception method is applied, the base station may not schedule other DMRS ports orthogonal to the corresponding DMRS port in the CDM group including the DMRS port indicated to the UE together to other UEs. As the first DMRS reception method, the UE may deactivate the orthogonal cover code for the indicated DMRS port and receive the PDSCH by using each of the multiple DMRS REs without applying the orthogonal cover code to be used for channel estimation, nor by using multiple DMDS REs and applying the orthogonal cover code for channel estimation. That is, the UE may assume that other DMRS ports orthogonal to the corresponding DMRS port in the CDM group including the corresponding DMRS port are not scheduled for other UEs. As the second DMRS reception method, the UE may activate the orthogonal cover code for the indicated DMRS port and receive the PDSCH by using multiple DMRS REs and applying the orthogonal cover code for channel estimation. When the second DMRS reception method is applied, the base station may schedule other DMRS ports orthogonal to the corresponding DMRS port in the CDM group including the DMRS port indicated to the UE together to other UEs.

[0539] The above-described operations are merely examples, not all operations are essential, and one of the operations may not be performed, the order may be changed or omitted, or other operations may be added.

[0540] <Example 3: Method for determining orthogonal cover codes when supporting enhanced DMRS types 1 and 2>

[0541] As an embodiment of the present disclosure, a method for determining an orthogonal cover code of a UE and a base station when supporting enhanced DMRS types 1 and 2 will be described. When enhanced DMRS types 1 and 2 are supported based on the various methods described in the above embodiments, in the case where the base station schedules PDSCH reception or PUSCH transmission based on enhanced DMRS types 1 and 2 through the various methods to be described below, the UE can determine the symbol of the orthogonal cover code to be applied to the DMRS RE. In addition, when the base station notifies the UE of a combination of higher layer signaling or / and L1 signaling for determining the symbol of the orthogonal cover code to be applied to the DMRS RE through the various methods to be described below, the base station can determine the symbol of the orthogonal cover code in the DMRS RE and send the PDSCH DMRS to the UE, so that the UE can receive the PDSCH by determining the symbol of the orthogonal cover code according to the indication of the base station, or when the UE determines the symbol of the orthogonal cover code according to the indication of the base station and sends the PUSCH, the base station can receive the PUSCH DMRS based on the code information of the orthogonal cover code indicated to the UE to receive the PUSCH.

[0542] This is because when multiple UEs are scheduled for the same time and frequency resources in a multi-user MIMO scenario, some UEs operate with enhanced DMRS type and some other UEs use regular DMRS type, and UEs operating with enhanced DMRS type or regular DMRS type may not be able to distinguish the DMRS allocated to the UE. Detailed examples can be found in Fig. 20 , and this disclosure is not subject to Fig. 20 Limitations of the examples.

[0543] [Method 3-1]

[0544] When the higher layer signaling for determining the symbol of the orthogonal cover code is configured from the base station, the UE can determine the symbol of the orthogonal cover code to be applied to the DMRS RE according to the corresponding higher layer signaling. For example, if the UE receives from the base station a configuration of the higher layer signaling for inverting the symbol of the orthogonal cover code as "enabled", the UE can invert the symbol of the predefined orthogonal cover code of each DMRS RE according to each DMRS port indication.

[0545] For example, in the case of enhanced DMRS type 1 support method 1, when DMRS port 0 corresponding to CDM group #0 is supported, for DMRS RE, the first RE, the fifth RE, the ninth RE of the first RB and the first RE, the fifth RE and the ninth RE of the second RB can all be multiplied by +1. That is, the orthogonal cover code applied to DMRS port 0 can be [+1, +1, +1, +1, +1, +1]. In addition, when DMRS port 0 corresponding to CDM group #0 is supported, for DMRS RE, the first RE, the fifth RE, the ninth RE of the first RB and the first RE, the fifth RE and the ninth RE of the second RB can be multiplied by +1, -1, +1, -1, +1 and -1, respectively. That is, the orthogonal cover code applied to DMRS port 1 can be [+1, -1, +1, -1, +1, -1]. In this case, if the UE receives the configuration of the higher layer signaling for inverting the symbol of the orthogonal cover code as "enabled", the orthogonal cover codes allocated to the DMRS ports 0 and 1 of the corresponding UE can be [-1, -1, -1, -1, -1, -1] and [-1, +1, -1, +1, -1, +1] respectively.

[0546] In addition to the above-mentioned higher layer signaling, the UE may also reconstruct the orthogonal cover code values ​​in each table so that a constant such as exp(j*ðp) is multiplied for each orthogonal cover code in the table in which the orthogonal cover code is defined in the standard. For higher layer signaling, the above-mentioned value of p may be used as 0 or 1. If the UE receives a configuration in which the value of p for higher layer signaling is 0, the UE uses the orthogonal cover code defined in the standard as is, and if the UE receives a configuration in which the value of p is 1, the UE may use an orthogonal cover code having an inversion code compared to the orthogonal cover code defined in the standard. Reconstruction may be applied to other methods.

[0547] [Method 3-2]

[0548] The UE receives L1 signaling from the base station for determining the sign of the orthogonal cover code, and determines the sign of the orthogonal cover code to be applied to the DMRS RE. The L1 signaling can be performed based on a new field in the DCI format 1_1 or 1_2 sent from the base station to the UE, based on a specific entry of a table referenced by the antenna port field in the DCI format 1_1 or 1_2, or based on an additional 1 bit in the antenna port in the DCI format 1_1 or 1_2. When receiving such L1 signaling, the UE can invert the sign of the predefined orthogonal cover code for each DMRS RE according to each DMRS port indication.

[0549] For example, in the case of enhanced DMRS type 1 support method 1, when DMRS port 0 corresponding to CDM group #0 is supported, for DMRS RE, the first RE, the fifth RE, the ninth RE of the first RB and the first RE, the fifth RE and the ninth RE of the second RB can all be multiplied by +1. That is, the orthogonal cover code applied to DMRS port 0 can be [+1, +1, +1, +1, +1, +1]. In addition, when DMRS port 0 corresponding to CDM group #0 is supported, for DMRS RE, the first RE, the fifth RE, the ninth RE of the first RB and the first RE, the fifth RE and the ninth RE of the second RB can be multiplied by +1, -1, +1, -1, +1 and -1, respectively. That is, the orthogonal cover code applied to DMRS port 1 can be [+1, -1, +1, -1, +1, -1]. In this case, if the UE receives a configuration of signaling for inverting the signs of the orthogonal cover codes, the orthogonal cover codes for DMRS ports 0 and 1 can be [-1, -1, -1, -1, -1, -1] and [-1, +1, -1, +1, -1, +1], respectively.

[0550] [Method 3-3]

[0551] The UE may be notified of information for determining the symbol of the orthogonal cover code based on a combination of a higher layer signaling configuration and an L1 signaling indication from the base station, and the symbol of the orthogonal cover code to be applied to the DMRS RE may be determined based on this. The corresponding higher layer signaling and L1 signaling may use a combination of at least one of the methods described in methods 3-1 and 3-2. For example, if the UE receives from the base station a configuration of higher layer signaling for inverting the symbol of the orthogonal cover code as "enabled", the UE may expect the table referenced by the antenna port field in DCI format 1_1 or 1_2 to include an entry for inverting the symbol of the orthogonal cover code, and if the higher layer signaling is configured as "disabled", the UE may expect the table referenced by the antenna port field in DCI format 1_1 or 1_2 to use a regular table that does not include an entry for inverting the symbol of the orthogonal cover code.

[0552] For example, in the case of enhanced DMRS type 1 support method 1, when DMRS port 0 corresponding to CDM group #0 is supported, for DMRS RE, the first RE, the fifth RE, the ninth RE of the first RB and the first RE, the fifth RE and the ninth RE of the second RB can all be multiplied by +1. That is, the orthogonal cover code applied to DMRS port 0 can be [+1, +1, +1, +1, +1, +1]. In addition, when DMRS port 0 corresponding to CDM group #0 is supported, for DMRS RE, the first RE, the fifth RE, the ninth RE of the first RB and the first RE, the fifth RE and the ninth RE of the second RB can be multiplied by +1, -1, +1, -1, +1 and -1, respectively. That is, the orthogonal cover code applied to DMRS port 1 can be [+1, -1, +1, -1, +1, -1]. In this case, if the UE receives a configuration of signaling for inverting the signs of the orthogonal cover codes, the orthogonal cover codes for DMRS ports 0 and 1 can be [-1, -1, -1, -1, -1, -1] and [-1, +1, -1, +1, -1, +1], respectively.

[0553] [Method 3-4]

[0554] The UE may receive MAC-CE signaling from the base station to be notified of activation of information for determining the symbol of the orthogonal cover code, and may determine the symbol of the orthogonal cover code to be applied to the DMRS RE based on this. The corresponding MAC-CE may be used to change the above-mentioned higher layer signaling value of the base station.

[0555] For example, if the UE receives a MAC-CE and the MAC-CE includes information for changing a higher layer signaling value for inverting the symbol of the orthogonal cover code from "enable" to "disable", the UE may restore the symbol of the orthogonal cover code applied to the DMRS port from the inverted state to the original state, and apply the symbol to the DMRS RE, which is indicated together when the PDSCH received from the base station after time slot 3 is scheduled for sending the HARQ-ACK of the corresponding MAC-CE. Conversely, if the UE receives a MAC-CE and the MAC-CE includes information for changing a higher layer signaling value for inverting the symbol of the orthogonal cover code from "disable" to "enable", the UE may invert the symbol of the orthogonal cover code applied to the DMRS port, which is indicated together when the PDSCH received from the base station after time slot 3 is scheduled for sending the HARQ-ACK of the corresponding MAC-CE, to be applied to the DMRS RE.

[0556] For another example, when the base station sends a MAC-CE to the UE to change the value of the higher layer signaling P in exp(j*ðP), which is a constant by which each orthogonal cover code is multiplied, from 0 to 1, the UE may invert the sign of the orthogonal cover code applied to the DMRS port indicated together when the PDSCH received from the base station after slot 3 is scheduled for sending the HARQ-ACK for the corresponding MAC-CE, and apply the sign to the DMRS RE. In addition, when the UE may receive a MAC-CE for activating an orthogonal cover code of an inverted sign to be applied to a predetermined entry of a table referenced by an antenna port field in a DCI format 1_1 or 1_2 indicated by the base station, and when the PDSCH received from the base station after slot 3 is scheduled for sending the HARQ-ACK for the corresponding MAC-CE, the entry of the orthogonal cover code to which the inverted sign is applied is indicated by the antenna port field in DCI formats 1_1 and 1_2, the UE may invert the sign of the orthogonal cover code applied to the DMRS port to be applied to the DMRS RE.

[0557] For example, in the case of enhanced DMRS type 1 support method 1, when DMRS port 0 corresponding to CDM group #0 is supported, for DMRS RE, the first RE, the fifth RE, the ninth RE of the first RB and the first RE, the fifth RE and the ninth RE of the second RB can all be multiplied by +1. That is, the orthogonal cover code applied to DMRS port 0 can be [+1, +1, +1, +1, +1, +1]. In addition, when DMRS port 0 corresponding to CDM group #0 is supported, for DMRS RE, the first RE, the fifth RE, the ninth RE of the first RB and the first RE, the fifth RE and the ninth RE of the second RB can be multiplied by +1, -1, +1, -1, +1 and -1, respectively. That is, the orthogonal cover code applied to DMRS port 1 can be [+1, -1, +1, -1, +1, -1]. In this case, if the UE receives a configuration of signaling for inverting the signs of the orthogonal cover codes, the orthogonal cover codes generated by the UE for DMRS ports 0 and 1 can be [-1, -1, -1, -1, -1, -1] and [-1, +1, -1, +1, -1, +1], respectively.

[0558] Fig. 20 Spatial multiplexing between existing DMRS types and enhanced DMRS types according to an embodiment of the present disclosure is shown.

[0559] The base station may schedule three UEs (UE#1 2000, UE#2 2001, and UE#3 2002) in a spatial multiplexing manner, and may use one DMRS port for each UE and use two RBs 2003 and 2004. DMRS port 0 based on DMRS type 1 is scheduled for UE#1, and thus an orthogonal cover code +1 may be used for each DMRS RE present every two REs from the first RE in two RBs. DMRS port 1 in CDM group 0 and DMRS port 5 in CDM group 2 based on enhanced DMRS type 1 according to the above-mentioned [Enhanced DMRS type support method 1] may be scheduled for UE#2 and UE#3, respectively. Therefore, UE#2 can consider multiplying the first RE, fifth RE and ninth RE of the first RB and the first RE, fifth RE and ninth RE of the second RB by +1, -1, +1, -1, +1, -1 respectively as orthogonal cover codes of DMRS RE, and UE#3 can consider multiplying the third RE, seventh RE and eleventh RE of the first RB and the third RE, seventh RE and eleventh RE of the second RB by +1, -1, +1, -1, +1 and -1 respectively.

[0560] Here, the DMRS REs for the three UEs overlap, and therefore each UE is required to be able to distinguish interference from other UEs through an orthogonal cover code when receiving PDSCH from the base station. Starting from the reception point of UE#3, since the two DMRS REs of UE#3 overlap with the two DMRS REs of UE#1 and use an orthogonal cover code of length 2 that is orthogonal to each other, the DMRS of UE#3 can be distinguished from the interference caused by the DMRS of UE#1 (2005). Starting from the reception point of UE#2, since the two DMRS REs of UE#2 overlap with the two DMRS REs of UE#1 and use an orthogonal cover code of length 2 that is orthogonal to each other, the DMRS of UE#2 can be distinguished from the interference caused by the DMRS of UE#1 (2006).

[0561] However, from the reception point of UE#1, since one of the two DMRS REs of UE#1 to which an orthogonal cover code of length 2 is applied overlaps with a DMRS RE of UE#2, the other of the two DMRS REs of UE#1 to which an orthogonal cover code of length 2 is applied overlaps with a DMRS RE of UE#3, and orthogonal cover codes of length 2 that are not orthogonal to each other are used, the DMRS of UE#1 may not be distinguishable from the DMRS of UE#2 and UE#3 (2007).

[0562] In this way, it may not be possible to distinguish the interference from the DMRS REs of other UEs by the orthogonal cover code, so the base station can notify UE#3 of the information for reversing the sign of the orthogonal cover code by a combination of at least one of the above [Method 3-1] to [Method 3-4], and the base station can send a DMRS with the sign of the orthogonal cover code reversed to UE#3 (2010). UE#3 can consider multiplying the third RE, the seventh RE and the eleventh RE of the first RB and the third RE, the seventh RE and the eleventh RE of the second RB by -1, +1, -1, +1, -1 and +1, respectively. In this case, starting from the reception point of UE#3, since the two DMRS REs of UE#3 overlap with the two DMRS REs of UE#1 and use orthogonal cover codes of length 2 that are orthogonal to each other, the DMRS of UE#3 can be distinguished from the interference caused by the DMRS of UE#1 (2011).

[0563] From the reception point of UE#2, since the two DMRS REs of UE#2 overlap with the two DMRS REs of UE#1 and use orthogonal cover codes of length 2 that are orthogonal to each other, the DMRS of UE#2 can be distinguished from the interference caused by the DMRS of UE#1 (2012). In addition, from the reception point of UE#1, since one of the two DMRS REs of UE#1 to which the orthogonal cover code of length 2 is applied overlaps with one DMRS RE of UE#2, the other of the two DMRS REs of UE#1 to which the orthogonal cover code of length 2 is applied overlaps with one DMRS RE of UE#3, and an orthogonal cover code of length 2 that is orthogonal to each other is used by inverting the sign of the orthogonal cover code of UE#3, the DMRS of UE#1 can be distinguished from the DMRS of UE#2 and UE#3 (2013).

[0564] The above contents in the embodiments are not only applied between conventional DMRS type 1 and enhanced DMRS type 1 based on [enhanced DMRS type 1 support method 1], but can be similarly applied between conventional DMRS types 1 and 2 and enhanced DMRS types 1 and 2 based on the method for supporting enhanced DMRS types 1 and 2 mentioned in the above embodiments.

[0565] The UE may report the above functions described as UE capabilities to the base station. Here, the functions that may be included in the UE capabilities may include at least one combination of the following.

[0566] In addition, the corresponding UE capability report may be valid for FR1 or for both FR1 and FR2. The corresponding UE capabilities may be reported with different values ​​for each frequency band, frequency band combination, feature set, feature set per CC, and per UE. Different values ​​may be reported according to the frequency band combination. After receiving the UE capabilities, the base station may configure higher layer signaling corresponding thereto and the higher layer signaling may correspond to one of the above methods or independent higher layer signaling.

[0567] <Embodiment 4: Demodulation Reference Signal Power Control Method When Supporting Enhanced DMRS Types 1 and 4>

[0568] As an embodiment of the present disclosure, a demodulation reference signal power control method of a base station and a UE when supporting enhanced DMRS types 1 and 2 will be described. As described above, since enhanced DMRS types 1 and 2 can use a method of increasing the number of orthogonal DMRS ports by using fewer REs than conventional DMRS types 1 and 2, a portion of the DMRS REs used by the UE in conventional DMRS type 1 may be interfered by a predetermined UE using enhanced DMRS types 1 and / or 2, and the remaining portion of the DMRS REs used in conventional DMRS type 1 may be interfered by another UE using enhanced DMRS types 1 and / or 2. That is, the UE may receive interference signals from different UEs in different DMRS REs, and in this case, an orthogonal cover code needs to be applied to the corresponding different DMRS REs, and when the power of the interference signals from different UEs received in different DMRS REs is different, problems may occur in channel estimation applying the orthogonal cover code of the UE. The case where the power of the interference signals from different UEs is different may include, for example, a case where different power ratios between PDSCH and DMRS are applied to the DMRS of different UEs causing interference.

[0569] Therefore, in the case where a UE configured with a conventional DMRS type 1 or 2 receives interference from a different UE configured with an enhanced DMRS type 1 or 2 at different DMRS RE positions, it can be assumed that the interference power of the DMRS REs of the different UEs is the same. In addition, in the case where a UE configured with a conventional DMRS type 1 or 2 receives interference from a different UE configured with an enhanced DMRS type 1 or 2 at different DMRS RE positions, it may not be expected that the interference power of the DMRS REs of the different UEs is different. For example, the UE can perform channel estimation under the assumption that the same power increase is applied to the DMRS of the other UE causing the interference.

[0570] Fig.21 A method for controlling DMRS power when supporting enhanced DMRS according to an embodiment of the present disclosure is shown.

[0571] The base station may schedule, for example, three UEs, UE#1 2100, UE#2 2101, and UE#3 2102, in a spatial multiplexing manner, and may use one DMRS port and two RBs for each UE. In this case, both UE#2 2101 and UE#3 2102 may correspond to the case where the "number of DMRS CDM groups without data" is all indicated as 3, which is information in the DMRS table entry indicated by the antenna port field included in DCI format 1_1 or 1_2. In enhanced DMRS type 1 support method 1, since the total number of CDM groups is 4 and the indicated "number of DMRS CDM groups without data" is 3, at the RE position where up to 3 DMRS CDM groups may exist starting from the low CDM group index, the indicated DMRS may be sent or the RE may be cleared (2111). The PDSCH may be sent at the RE position where the fourth DMRS CDM group may exist (2110). Therefore, considering the above-mentioned power ratio between PDSCH and DMRS, up to 4.77 dB of power increase may occur in both UE#2 and UE#3. Even in this case, UE#1 can expect the same power of two different interference signals on two different REs interfered by the DMRS REs of UE#2 and UE#3. The base station can perform scheduling so that the same power ratio between PDSCH and DMRS is applied to the DMRS allocated to the concurrently scheduled UEs, which may cause interference to the intended UE. As an example, through the scheduling method, the base station can allocate DMRS to the UEs scheduled together so that the value of the number of DMRS CDM groups without data is the same.

[0572] In contrast, in the case where the "number of DMRS CDM groups without data" is indicated to UE#2 as 3, but is indicated to UE#3 as 4, the "number of DMRS CDM groups without data" is information in the DMRS table entry indicated by the antenna port field included in DCI format 1_1 or 1_2, and when the above-mentioned power ratio between PDSCH and DMRS is considered, a power increase of 4.77 and 6 dB may occur in both UE#2 and UE#3. Therefore, UE#1 may expect different powers of two different interference signals with respect to two different REs interfered by the DMRS REs of UE#2 and UE#3. However, the UE may not expect such scheduling, and may expect the interference powers received from different UEs in different REs to be similar or equal to each other. The base station may not perform PDSCH and PDSCH DMRS, and PUSCH and PUSCH DMRS scheduling, so that the DMRS REs of multiple different UEs have different interference powers to the DMRS REs of one UE.

[0573] <Example 5: Multi-user MIMO support method using enhanced DMRS type>

[0574] As an embodiment of the present disclosure, a multi-user MIMO supporting method using an enhanced DMRS type will be described. This embodiment may operate in combination with at least one of Embodiments 1 to 4.

[0575] It is assumed that the UE is configured for enhanced DMRS type 1 through higher layer signaling from the base station, and the UE receives scheduling information for PDSCH reception from the base station, that is, the corresponding UE receives the DMRS transmitted from the base station based on the definition of enhanced DMRS type 1 when receiving the PDSCH. In this case, the UE may assume a combination of at least one of the following items regarding the presence of other UEs scheduled by the base station in a multi-user MIMO (MU-MIMO) scheme in a CDM group in which the allocated DMRS port exists. The multi-user MIMO scheme may refer to a case where the DMRS ports allocated to multiple users are orthogonal to each other. Here, the case where the DMRS port defined based on DMRS type 1 and the DMRS port defined based on enhanced DMRS type 1 exist in the same CDM group may be assumed based on the case where the DMRS port is defined based on [enhanced DMRS type 1 support method 6] among various methods for supporting enhanced DMRS type 1. In this case, since DMRS type 1 and enhanced DMRS type 1 have the same DMRS RE mapping position and the same defined CDM group, the same CDM group can be used for both DMRS types. In this case, even if the DMRS ports are within the same CDM group, the DMRS ports defined based on DMRS type 1 and the DMRS ports defined based on enhanced DMRS type 1 may be different.

[0576] -When receiving a PDSCH DMRS from a base station, the UE may assume that there is no restriction on whether a DMRS port for another UE scheduled by the base station in a multi-user MIMO scheme exists in the CDM group including the corresponding DMRS port. In other words, the UE may assume that there is no restriction on the base station using one or more other DMRS ports in the corresponding CDM group to schedule other UEs in the multi-user MIMO scheme. The corresponding UE may receive configuration information about DMRS type 1 or enhanced DMRS type 1 from the base station through higher signaling, and may receive a DMRS port in a corresponding CDM group defined based thereon. Here, the meaning of no restriction may be understood as DMRS ports allocated to different UEs may not necessarily be orthogonal to each other.

[0577] -The present disclosure contemplates a situation in which a UE is scheduled with one or more of DMRS ports 1000 to 1007 based on enhanced DMRS type 1 for PDSCH reception from a base station, and the base station schedules one or more other UEs in a multi-user MIMO scheme using one or more other DMRS ports in the same CDM group as the DMRS port to which the corresponding UE is scheduled. In this case, the corresponding UE may expect one or more other UEs scheduled in a multi-user MIMO scheme to receive a DMRS type 1 configuration from the base station and perform operations accordingly. The one or more other UEs scheduled in a multi-user MIMO scheme may be UEs of an earlier version than the corresponding UE, or may be UEs of a version that is capable of receiving an enhanced DMRS type 1 configuration like the corresponding UE. An earlier version UE may be referred to as a UE that is not capable of supporting enhanced DMRS type 1. In addition, the UE may expect that the DMRS port allocated to the corresponding UE and the DMRS port allocated to one or more other UEs scheduled by the base station in a multi-user MIMO scheme are orthogonal.

[0578] -The present disclosure contemplates a situation in which a corresponding UE is scheduled with one or more of DMRS ports 1008 to 1015 based on enhanced DMRS type 1 for PDSCH reception from a base station, and the corresponding UE and one or more other UEs are configured with DMRS type 1 through higher layer signaling from the base station. Here, the corresponding UE may not expect the corresponding UE and one or more other UEs to be scheduled by the base station in a multi-user MIMO scheme in the same CDM group. That is, it may not be expected that DMRS ports scheduled for one or more other UEs different from the corresponding UE are included in the same CDM group as the DMRS ports scheduled for the corresponding UE. One or more UEs may correspond to UEs of an earlier version. UEs of an earlier version may be referred to as UEs that are not capable of supporting enhanced DMRS type 1.

[0579] -The present disclosure contemplates a situation in which a UE is scheduled with one or more of DMRS ports 1008 to 1015 based on enhanced DMRS type 1 for PDSCH reception from a base station, and the corresponding UE and one or more other UEs are configured with DMRS type 1 through higher layer signaling from the base station. Here, the corresponding UE may not expect the corresponding UE and one or more other UEs to be scheduled by the base station in a multi-user MIMO scheme in the same CDM group. That is, it may not be expected that DMRS ports scheduled for one or more other UEs different from the corresponding UE are included in the same CDM group as the DMRS ports scheduled for the corresponding UE. In this case, the one or more other UEs may be UEs of the same version as the corresponding UE, and the UEs of the same version may be UEs capable of supporting enhanced DMRS type 1.

[0580] -The present disclosure contemplates a situation in which a UE is scheduled with a DMRS port based on enhanced DMRS type 1 for PDSCH reception from a base station, and the corresponding UE and one or more other UEs receive enhanced DMRS type 1 configuration through higher layer signaling and receive scheduling of one or more of DMRS ports 1008 to 1015 based on enhanced DMRS type 1. Here, the corresponding UE may expect the corresponding UE and one or more other UEs to be scheduled by the base station in a multi-user MIMO scheme in the same CDM group. In other words, it may be expected that the DMRS port on which the corresponding UE is scheduled and the DMRS port on which the corresponding UE and one or more other UEs are scheduled belong to the same CDM group. In addition, it may be expected that the DMRS port on which the corresponding UE is scheduled and the DMRS port on which the corresponding UE and one or more other UEs are scheduled are orthogonal to each other by using OCC.

[0581] Here, the corresponding UE may receive a notification from the base station that one or more UEs among other UEs (scheduled in a multi-user MIMO scheme in the same CDM group) are scheduled with one or more DMRS ports 1008 to 1015 based on enhanced DMRS type 1, and the corresponding notification may be semi-statically configured by higher layer signaling, activated by MAC-CE, dynamically indicated by L1 signaling, or notified by a combination of higher layer signaling and L1 signaling. More specifically, in the case where the UE receives configuration information indicating that multi-user MIMO scheduling is possible from the base station through higher layer signaling, the UE may receive a higher layer signaling configuration indicating that the UE may apply an FD-OCC having a length of 4 to a DMRS port defined based on DMRS type 1 and receive the DMRS port. The higher layer signaling may be included in the DMRS type 1 configuration information. As an example, a UE that has received higher layer signaling may apply FD-OCC [+1 +1 +1 +1] with a length of 4 in addition to applying FD-OCC [+1 +1] with a length of 2 to DMRS port 1000 defined based on DMRS type 1, and may apply FD-OCC [+1-1+1-1] with a length of 4 in addition to applying FD-OCC [+1-1] with a length of 2 to DMRS port 1001, in order to perform channel estimation.

[0582] Here, the corresponding UE may be a UE that can receive a version of the enhanced DMRS type 1 like one or more other UEs, and may be a UE that has reported to the base station the UE capabilities that the enhanced DMRS type 1 can support. Alternatively / additionally, the corresponding UE may be a UE that has reported to the base station the UE capabilities that indicate, among the FD-OCC with a length of 2 that can be used when the configuration of the DMRS type 1 is received from the base station through higher layer signaling and the FD-OCC with a length of 4 that can be used when the configuration of the enhanced DMRS type 1 is received, at least one FD-OCC that can be dynamically and freely applied without restriction during channel estimation. Alternatively, in addition, the corresponding UE may additionally report the UE capabilities that indicate that the UE can receive notification from the base station and understand that the base station is capable of multi-user MIMO scheduling, and this may mean that an FD-OCC with a length of 4 can be applied, which can be used when the UE receives a DMRS port defined based on the enhanced DMRS type 1 according to the UE capabilities despite the configuration of the DMRS type 1. In this case, when the FD-OCC having a length of 4 is applied, the corresponding UE may expect that a DMRS port of the corresponding UE scheduled in a multi-user MIMO scheme in a corresponding CDM group and a DMRS port allocated to other UEs are orthogonal.

[0583] -The present disclosure contemplates a situation in which a UE is scheduled with a DMRS port based on DMRS type 1 for PDSCH reception from a base station, and the corresponding UE and one or more other UEs receive an enhanced DMRS type 1 configuration through higher layer signaling and receive scheduling of one or more of DMRS ports 1008 to 1015 based on enhanced DMRS type 1. Here, the corresponding UE may expect the corresponding UE and the one or more other UEs to be scheduled by the base station in a multi-user MIMO scheme in the same CDM group. In other words, it can be expected that the DMRS port on which the corresponding UE is scheduled and the DMRS port on which the corresponding UE and one or more other UEs are scheduled belong to the same CDM group. In addition, it can be expected that the DMRS port on which the corresponding UE is scheduled and the DMRS port on which the corresponding UE and one or more other UEs are scheduled are orthogonal to each other by using OCC.

[0584] Here, the corresponding UE may receive a notification from the base station that one or more UEs among other UEs (scheduled in a multi-user MIMO scheme) in the same CDM group are scheduled with one or more DMRS ports 1008 to 1015 based on enhanced DMRS type 1, and the corresponding notification may be semi-statically configured through higher layer signaling, activated through MAC-CE, dynamically indicated through L1 signaling, or notified through a combination of higher layer signaling and L1 signaling. More specifically, in the case where the UE receives configuration information indicating that multi-user MIMO scheduling is possible from the base station through higher layer signaling, the UE may receive a higher layer signaling configuration that may be included in the DMRS type 1 configuration information, indicating that the UE may apply an FD-OCC having a length of 4 to the DMRS ports defined based on DMRS type 1 and receive it. As an example, a UE that has received higher layer signaling may apply FD-OCC[+1 +1 +1 +1] with a length of 4 in addition to applying FD-OCC[+1 +1] with a length of 2 to DMRS port 1000 defined based on DMRS type 1, and may apply FD-OCC[+1-1+1-1] with a length of 4 in addition to applying FD-OCC[+1-1] with a length of 2 to DMRS port 1001, in order to perform channel estimation.

[0585] Here, the corresponding UE may be a UE that can receive a version of the enhanced DMRS type 1 like one or more other UEs, and may be a UE that has reported to the base station the UE capabilities that the enhanced DMRS type 1 can support. Alternatively / additionally, the corresponding UE may be a UE that has reported to the base station the UE capabilities, the UE capabilities indicating that at least one FD-OCC that can be dynamically and freely applied without restriction during channel estimation among the FD-OCC with a length of 2 that can be used when the configuration of the DMRS type 1 is received from the base station through higher layer signaling and the FD-OCC with a length of 4 that can be used when the configuration of the enhanced DMRS type 1 is received. Alternatively, in addition, the corresponding UE may additionally report the UE capabilities, the UE capabilities indicating that the UE can receive notification from the base station and understand that the base station is capable of multi-user MIMO scheduling, and this may mean that an FD-OCC with a length of 4 can be applied, which can be used when the UE receives a DMRS port defined based on the enhanced DMRS type 1 according to the UE capabilities despite the configuration of the DMRS type 1. In this case, when the FD-OCC having a length of 4 is applied, the corresponding UE can expect that the DMRS port of the corresponding UE scheduled in the multi-user MIMO scheme in the corresponding CDM group and the DMRS ports allocated to other UEs are orthogonal.

[0586] -The present disclosure contemplates a case where a UE is scheduled with a DMRS port based on DMRS type 1 for PDSCH reception from a base station, and the corresponding UE and one or more other UEs receive enhanced DMRS type 1 configuration through higher layer signaling and receive scheduling of one or more of DMRS ports 1008 to 1015 based on enhanced DMRS type 1. Here, the corresponding UE may expect no restriction on scheduling the corresponding UE and the one or more other UEs in a multi-user MIMO scheme in the same CDM group by the base station.

[0587] In this case, the UE may be a UE that has reported UE capabilities to the base station, the UE capabilities indicating that the UE can perform effective channel estimation even when one or more DMRS ports 1008 to 1015 based on enhanced DMRS type 1 allocated to one or more other UEs are allocated, and the one or more other UEs are scheduled in a multi-user MIMO scheme in the same CDM group as the DMRS port to which the UE is allocated. For example, since the UE can only distinguish orthogonal DMRS ports when FD-OCC is applied, a method for estimating the channel without applying an FD-OCC of length 2 or 4 can be used. For another example, even in the case where the FD-OCC is not orthogonal, the UE can perform non-orthogonal channel estimation at the same time and frequency resources by receiving DMRS sequence index configuration differently for each UE from the base station.

[0588] Regarding the above, the embodiments have been described based on enhanced DMRS type 1, but the UE and the base station can perform similar operations based on enhanced DMRS type 2. In other words, the above embodiments can be applied based on DMRS type 2 and enhanced DMRS type 2. In addition, in the case where the UE operates based on enhanced DMRS type 2, it can be assumed that the UE defines the DMRS port based on [Enhanced DMRS type 2 support method 3] among various methods for supporting enhanced DMRS type 2. For example, the UE can receive a higher layer signaling configuration regarding enhanced DMRS type 2 from the base station, and when receiving the PDSCH DMRS from the base station, the UE can assume that there is no restriction on whether the DMRS port for another UE scheduled by the base station in a multi-user MIMO scheme exists in the CDM group including the corresponding DMRS port. Here, another UE scheduled in a multi-user MIMO scheme can be configured with DMRS type 2 or enhanced DMRS type 2 through higher layer signaling from the base station.

[0589] In addition, with respect to the above, an embodiment has been described for PDSCH reception of a UE, but a similar operation may be performed when the UE sends a PUSCH and the base station receives the PUSCH. In other words, the above embodiment may be applied based on DMRS type 1, enhanced DMRS type 1, DMRS type 2, and enhanced DMRS type 2 for PUSCH. For example, the UE may assume that there is no restriction on whether there is a DMRS port for another UE scheduled by a base station in a CDM group in a multi-user MIMO scheme, and the CDM group includes a DMRS port that is instructed to send a PUSCH to the base station. That is, within the corresponding CDM group, the UE may assume that there is no restriction on scheduling other UEs by the base station, and the base station may receive a DMRS port defined and sent by the corresponding other UE in the same CDM group based on DMRS type 1 or enhanced DMRS type 1.

[0590] Fig. 22 An example of an operation of a UE for performing DMRS reception according to an embodiment of the present disclosure is shown.

[0591] The UE may send the above-mentioned UE capabilities to the base station (2200). In this case, the UE capabilities that may be reported may include information about whether the UE supports symbol determination (or / and symbol inversion) of the orthogonal cover code applied to the DMRS as described above. Thereafter, the UE receives information for enhancing DMRS type 1 or / and 2 or / and information for determining the symbol of the orthogonal cover code from the base station (2210). The information for enhancing DMRS type 1 or / and 2 from the base station may be as described above, and the information for determining the symbol of the orthogonal cover code may be as described above. For example, the information for determining the symbol of the orthogonal cover code may include a combination of at least one of higher layer signaling and L1 signaling.

[0592] The UE may receive PDSCH scheduling information (2220). Here, in the case of PDSCH, the scheduling information may be notified through DCI format 1_1 or 1_2, and according to an embodiment of the present disclosure, the scheduling information may also include information for determining the symbol of the orthogonal cover code. The UE may determine the orthogonal cover code to be applied to the DMRS according to a combination of at least one of the above methods 3-1 to 3-4. As an example, the UE as described above may estimate the channel by using the inverted orthogonal cover code when the inversion of the orthogonal cover code is indicated.

[0593] The above-described operations are merely examples, not all operations are essential, and one of the operations may not be performed, the order may be changed or omitted, or other operations may be added.

[0594] Fig.23An example of the operation of a base station for performing DMRS transmission according to an embodiment of the present disclosure is shown.

[0595] The base station may receive the above-mentioned UE capabilities from the UE (2300). In this case, the UE capabilities that may be reported may include information about whether the UE supports symbol determination (or / and symbol inversion) of the orthogonal cover code applied to the DMRS as described above. Thereafter, the base station sends information for enhancing DMRS type 1 or / and 2 or / and information for determining the symbol of the orthogonal cover code to the UE (2310). The information for enhancing DMRS type 1 or / and 2 from the base station may be as described above, and the information for determining the symbol of the orthogonal cover code may be as described above. For example, the information for determining the symbol of the orthogonal cover code may include a combination of at least one of higher layer signaling or L1 signaling.

[0596] The base station may send PDSCH scheduling information to the UE (2320). Here, in the case of PDSCH, the scheduling information may be notified through DCI format 1_1 or 1_2, and according to an embodiment of the present disclosure, the scheduling information may also include information for determining the symbol of the orthogonal cover code. The base station determines the orthogonal cover code to be applied to the DMRS, sends the information for determining the symbol of the orthogonal cover code to the UE according to a combination of at least one of the above methods 3-1 to 3-4, generates the DMRS by using the determined orthogonal cover code, and sends the DMRS to the UE.

[0597] The above-described operations are merely examples, not all operations are essential, and one of the operations may not be performed, the order may be changed or omitted, or other operations may be added.

[0598] The above contents in the embodiments are not only applied between conventional DMRS type 1 and enhanced DMRS type 1 based on [enhanced DMRS type 1 support method 1], but can be similarly applied between conventional DMRS types 1 and 2 and enhanced DMRS types 1 and 2 based on the method for supporting enhanced DMRS types 1 and 2 mentioned in the above embodiments.

[0599] The UE may report the above functions described as UE capabilities to the base station. Here, the functions that may be included in the UE capabilities may include at least one combination of the following.

[0600] In addition, the corresponding UE capability report may be valid for FR1 or for both FR1 and FR2. The corresponding UE capabilities may be reported with different values ​​for each frequency band, frequency band combination, feature set, feature set per CC, and per UE. Different values ​​may be reported according to the frequency band combination. After receiving the UE capabilities, the base station may configure higher layer signaling corresponding thereto and the higher layer signaling may correspond to one of the above methods or independent higher layer signaling.

[0601] One or more combinations of the above-mentioned embodiments 1 to 4 may be used. For example, the enhanced DMRS type may be indicated to the UE according to embodiment 1, the CDM group or RE of the DMRS may follow embodiment 2, the orthogonal cover code may be changed according to embodiment 3 if necessary, or the power of the DMRS RE of another UE causing interference may be identified according to embodiment 4. This combination is only an example, and the combination of the embodiments of the present disclosure is not limited to this example.

[0602] Although the above description is mainly for PDSCH DMRS, based on the clear understanding of those skilled in the art, the content of the present disclosure can be applied to PUSCH DMRS. In this case, the base station sends PUSCH scheduling information through DCI format 0_0 or 0_1 and the PUSCH scheduling information may include DMRS configuration information, such as antenna port. The UE may generate a PUSCH DMRS according to at least one of Embodiments 1 to 4, and send the PUSCH DMRS together with uplink data.

[0603] Fig.24 The structure of a UE in a wireless communication system according to an embodiment of the present disclosure is shown.

[0604] refer to Fig.24 , the UE may include a transceiver indicating a UE receiver 2400 and a UE transmitter 2410, a memory (not shown), and a UE processor 2405 (or a UE controller or processor). The transceivers 2400 and 2410, the memory, and the UE processor 2405 of the UE may operate according to the above-mentioned UE communication method. However, the components of the UE are not limited to the above-mentioned examples. For example, the UE may include more or fewer components than the above-mentioned components. In addition, the transceiver, the memory, and the processor may be implemented in the form of a single chip.

[0605] The transceiver can send or receive signals to or from a base station. Here, the signal may include control information and data. To this end, the transceiver may include an RF transmitter configured to up-convert and amplify the frequency of the transmitted signal, an RF receiver configured to amplify the received signal with low noise and down-convert the frequency, etc. However, this is only an embodiment of the transceiver, and the components of the transceiver are not limited to the RF transmitter and the RF receiver.

[0606] In addition, the transceiver may receive a signal through a wireless channel, output the signal to the processor, and transmit a signal output from the processor through the wireless channel.

[0607] The memory may store programs and data necessary 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 include a storage medium such as ROM, RAM, hard disk, CD-ROM, and DVD, or a combination of storage media. In addition, the memory may be multiple.

[0608] In addition, the processor can control a series of processes so that the UE operates according to the above-mentioned embodiments. For example, the processor can control the components of the UE to receive multiple PDSCHs simultaneously by receiving DCI including two layers. There may be multiple processors, and the processor can perform operations to control the components of the UE by executing a program stored in a memory.

[0609] Fig.25 The structure of a base station in a wireless communication system according to an embodiment of the present disclosure is shown.

[0610] refer to Fig.25 , the base station may include a transceiver indicating a base station receiver 2500 and a base station transmitter 2510, a memory (not shown), and a base station processor 2505 (or a base station controller or processor). The transceivers 2500 and 2510, the memory, and the base station processor 2505 of the base station may operate according to the above-mentioned base station communication method. However, the components of the base station are not limited to the above-mentioned examples. For example, the base station may include more or fewer components than the above-mentioned components. In addition, the transceiver, the memory, and the processor may be implemented in the form of a single chip.

[0611] The transceiver can send or receive signals to or from the UE. Here, the signal may include control information and data. To this end, the transceiver may include an RF transmitter configured to up-convert and amplify the frequency of the transmitted signal, an RF receiver configured to amplify the received signal with low noise and down-convert the frequency, etc. However, this is only an embodiment of the transceiver, and the components of the transceiver are not limited to the RF transmitter and the RF receiver.

[0612] In addition, the transceiver may receive a signal through a wireless channel, output the signal to the processor, and transmit a signal output from the processor through the wireless channel.

[0613] The memory may store programs and data required for the operation of the base station. In addition, the memory may store control information or data included in the signals sent and received by the base station. The memory may include a storage medium such as ROM, RAM, hard disk, CD-ROM and DVD, or a combination of storage media. In addition, the memory may be multiple.

[0614] The processor may control a series of processes so that the base station operates according to an embodiment of the present disclosure. For example, the processor may control the components of the base station to configure a two-layer DCI including allocation information of multiple PDSCHs, and control each component of the base station to send the DCI. There may be multiple processors, and the processor may perform operations to control the components of the base station by executing a program stored in a memory.

[0615] 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.

[0616] When the method is 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 within an electronic device. At least one program may include instructions for causing an electronic device to perform a method according to various embodiments of the present disclosure as defined by the appended claims and / or disclosed herein.

[0617] The program (software module or software) can be stored in a non-volatile memory, including random access memory and flash memory, read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), magnetic disk storage device, compact disk-ROM (CD-ROM), digital versatile disk (DVD) or other type of optical storage device or tape cassette. Alternatively, any combination of some or all of them can form the memory in which the program is stored. In addition, multiple such memories may be included in the electronic device.

[0618] 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 LAN (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, a separate storage device on a communication network can access the portable electronic device.

[0619] 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 ease of description, the singular form or plural form is appropriately selected for the presented situation, and the present disclosure is not limited to the elements expressed in the singular or plural. Therefore, an element expressed in the plural may also include a single element, or an element expressed in the singular may also include multiple elements.

[0620] The embodiments of the present disclosure described and shown in the specification and the drawings are merely specific examples 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 variations based on the technical ideas of the present disclosure can be implemented. In addition, the above-mentioned various embodiments can be combined as needed. For example, a part of an embodiment of the present disclosure can be combined with a part of another embodiment to operate a base station and a terminal. As an example, a part of embodiment 1 of the present disclosure can be combined with a part of embodiment 2 to operate a base station and a terminal. Moreover, 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 systems such as TDD LTE, 5G, and NR systems.

[0621] In the drawings describing the methods of the present disclosure, the order of description does not always correspond to the order of performing the steps of each method, and the sequential relationship between the steps may be changed or the steps may be performed in parallel.

[0622] 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.

[0623] Furthermore, in the method of the present disclosure, some or all of the contents of each embodiment may be implemented in combination without departing from the basic spirit and scope of the present disclosure.

[0624] Various embodiments of the present disclosure have been described above. The above description of the present disclosure is for illustrative purposes only, and the embodiments of the present disclosure are not limited to the embodiments set forth herein. It will be appreciated by those skilled in the art that other specific modifications and changes can be easily made without departing from the technical concept or basic features of the present disclosure. The scope of the present disclosure should not be determined by the above description, but by the appended claims, and all modifications or changes derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as falling within the scope of the present disclosure.

[0625] Although the present disclosure has been described with various embodiments, various changes and modifications may be suggested to one 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 comprising: receiving configuration information about an enhanced demodulation reference signal (DMRS) for a physical downlink shared channel (PDSCH) from a base station; receiving downlink control information (DCI) for scheduling a PDSCH from a base station, the DCI including antenna port information associated with an enhanced DMRS; as well as Receive downlink data and enhanced DMRS from the base station on PDSCH based on DCI, Wherein, in the case where the enhanced DMRS corresponds to enhanced DMRS type 1, the enhanced DMRS can support up to 16 antenna ports based on a frequency domain (FD)-orthogonal cover code (OCC) with a length of 4, and In which, when the enhanced DMRS corresponds to enhanced DMRS type 2, the enhanced DMRS can support up to 24 antenna ports based on an FD-OCC with a length of 4.

2. The method according to claim 1, wherein: In case the enhanced DMRS corresponds to enhanced DMRS type 1, a FD-OCC of length 4 is applied to 4 consecutive resource elements (REs), where the difference between subcarrier indices of REs in symbols within a resource block (RB) or across RBs is 2.

3. The method according to claim 1, wherein: In the case where the enhanced DMRS corresponds to enhanced DMRS type 2, an FD-OCC of length 4 is applied to 4 REs, the 4 REs including 2 sets of 2 consecutive REs, where the difference between subcarrier indices of each set in symbols within an RB is 6.

4. The method according to claim 1, wherein: In the case where the enhanced DMRS corresponds to enhanced DMRS type 1 and one or more allocated antenna ports are included in antenna ports 1000 to 1007, the antenna ports of DMRS type 1 of the code division multiplexing (CDM) group corresponding to the one or more allocated antenna ports of the terminal are not limited to being allocated to another co-scheduled terminal.

5. A method performed by a base station in a wireless communication system, the method comprising: Sending configuration information about an enhanced demodulation reference signal (DMRS) for a physical downlink shared channel (PDSCH) to a terminal; Sending downlink control information (DCI) for scheduling PDSCH to the terminal, where the DCI includes antenna port information associated with the enhanced DMRS; as well as Send downlink data and enhanced DMRS to the terminal on PDSCH, Wherein, in the case where the enhanced DMRS corresponds to enhanced DMRS type 1, the enhanced DMRS can support up to 16 antenna ports based on a frequency domain (FD)-orthogonal cover code (OCC) with a length of 4, and In which, when the enhanced DMRS corresponds to enhanced DMRS type 2, the enhanced DMRS can support up to 24 antenna ports based on an FD-OCC with a length of 4.

6. The method according to claim 5, wherein: In case the enhanced DMRS corresponds to enhanced DMRS type 1, a FD-OCC of length 4 is applied to 4 consecutive resource elements (REs), where the difference between subcarrier indices of REs in symbols within a resource block (RB) or across RBs is 2.

7. The method according to claim 5, wherein: In the case where the enhanced DMRS corresponds to enhanced DMRS type 2, an FD-OCC of length 4 is applied to 4 REs, the 4 REs including 2 sets of 2 consecutive REs, where the difference between subcarrier indices of each set in symbols within an RB is 6.

8. The method according to claim 5, wherein: In the case where the enhanced DMRS corresponds to enhanced DMRS type 1 and one or more allocated antenna ports are included in antenna ports 1000 to 1007, the antenna ports of DMRS type 1 of the code division multiplexing (CDM) group corresponding to the one or more allocated antenna ports of the terminal are not limited to being allocated to another co-scheduled terminal.

9. A terminal in a wireless communication system, the terminal comprising: Transceiver; as well as A controller is coupled to the transceiver and is configured to: receiving configuration information about an enhanced demodulation reference signal (DMRS) for a physical downlink shared channel (PDSCH) from a base station, receiving downlink control information (DCI) scheduling the PDSCH from the base station, the DCI including antenna port information associated with the enhanced DMRS, and Receive downlink data and enhanced DMRS from the base station on PDSCH based on DCI, Wherein, in the case where the enhanced DMRS corresponds to enhanced DMRS type 1, the enhanced DMRS can support up to 16 antenna ports based on a frequency domain (FD)-orthogonal cover code (OCC) with a length of 4, and In which, when the enhanced DMRS corresponds to enhanced DMRS type 2, the enhanced DMRS can support up to 24 antenna ports based on an FD-OCC with a length of 4.

10. The terminal according to claim 9, wherein: In case the enhanced DMRS corresponds to enhanced DMRS type 1, a FD-OCC of length 4 is applied to 4 consecutive resource elements (REs), where the difference between subcarrier indices of REs in symbols within a resource block (RB) or across RBs is 2.

11. The terminal according to claim 9, wherein: In the case where the enhanced DMRS corresponds to enhanced DMRS type 2, an FD-OCC of length 4 is applied to 4 REs, the 4 REs including 2 sets of 2 consecutive REs, where the difference between subcarrier indices of each set in symbols within an RB is 6.

12. The terminal according to claim 9, wherein: In the case where the enhanced DMRS corresponds to enhanced DMRS type 1 and one or more allocated antenna ports are included in antenna ports 1000 to 1007, the antenna ports of DMRS type 1 of the code division multiplexing (CDM) group corresponding to the one or more allocated antenna ports of the terminal are not limited to being allocated to another co-scheduled terminal.

13. A base station in a communication system, the base station comprising: Transceiver; as well as A controller is coupled to the transceiver and is configured to: Sending configuration information about an enhanced demodulation reference signal (DMRS) for a physical downlink shared channel (PDSCH) to a terminal, Sending downlink control information (DCI) for scheduling PDSCH to the terminal, the DCI including antenna port information associated with the enhanced DMRS, and Send downlink data and enhanced DMRS to the terminal on PDSCH, Wherein, in the case where the enhanced DMRS corresponds to enhanced DMRS type 1, the enhanced DMRS can support up to 16 antenna ports based on a frequency domain (FD)-orthogonal cover code (OCC) with a length of 4, and In which, when the enhanced DMRS corresponds to enhanced DMRS type 2, the enhanced DMRS can support up to 24 antenna ports based on an FD-OCC with a length of 4.

14. The base station according to claim 13, wherein: In case the enhanced DMRS corresponds to enhanced DMRS type 1, a FD-OCC of length 4 is applied to 4 consecutive resource elements (REs), where the difference between subcarrier indices of REs in symbols within a resource block (RB) or across RBs is 2.

15. The base station according to claim 13, wherein: In the case where the enhanced DMRS corresponds to enhanced DMRS type 2, an FD-OCC of length 4 is applied to 4 REs, the 4 REs including 2 sets of 2 consecutive REs, where the difference between subcarrier indices of each set in symbols within an RB is 6.

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