Method and apparatus for transmitting and receiving multiple data in a wireless cooperative communication system

Abstract

The present disclosure relates to a communication method and system for integrating a fifth generation (5G) communication system for supporting a higher data rate than a fourth generation (4G) system with Internet of Things (IoT) technology. The present disclosure can be applied to intelligent services based on 5G communication technology and IoT-related technologies, such as smart homes, smart buildings, smart cities, smart cars, connected cars, health care, digital education, smart retail, safety and security services. A method and apparatus for exchanging configuration information related to a demodulation reference signal (DMRS) are provided, in particular for providing DMRS ports included in different code division multiplexing groups for communication between a terminal and a base station.

Description

Technical Field

[0001] The present disclosure relates to a wireless communication system, and more particularly to a method and apparatus for transmitting and receiving a plurality of data in a wireless cooperative communication system. Background Art

[0002] In order to meet the demand for increasing wireless data traffic since the deployment of the fourth generation (4G) communication system, efforts have been made to develop an improved fifth generation (5G) or quasi-5G communication system. Therefore, the 5G or quasi-5G communication system is also called "super 4G network" or "post-long term evolution (LTE) system". The 5G communication system is considered to be implemented in a higher frequency (millimeter wave) band (such as the 60GHz band) in order to achieve higher data rates. In order to reduce the propagation loss of radio waves and increase the transmission distance, technologies such as beamforming, massive multiple input multiple output (MIMO), full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and massive antennas are discussed in the 5G communication system. In addition, in the 5G communication system, based on advanced small cells, cloud radio access networks (RAN), ultra-dense networks, device-to-device (D2D) communications, wireless backhaul, mobile networks, cooperative communications, coordinated multi-point (CoMP), receiving-end interference elimination, etc., development of system network improvements is underway. In 5G systems, hybrid FSK and QAM modulation (FQAM) and sliding window superposition coding (SWSC) have been developed as advanced coded modulation (ACM), and filter bank multi-carrier (FBMC), non-orthogonal multiple access (NOMA) and sparse code multiple access (SCMA) as advanced access technologies.

[0003] The Internet, which is a human-centered connected network in which people generate and consume information, is now evolving into the Internet of Things (IoT), in which distributed entities (such as things) exchange and process information without human intervention. The Internet of Everything (IoE), which is a combination of IoT technology and big data processing technology through connection with cloud servers, has emerged. Because IoT implementation requires technical elements such as "sensing technology", "wired / wireless communication and network infrastructure", "service interface technology" and "security technology", sensor networks, machine-to-machine (M2M) communication, machine type communication (MTC), etc. have been studied recently. Such an IoT environment can provide smart Internet technology services that create new value for human life by collecting and analyzing data generated between connected things. IoT can be applied to various fields including smart homes, smart buildings, smart cities, smart cars or connected cars, smart grids, healthcare, smart appliances, and advanced medical services through the integration and combination of existing information technology (IT) with various industrial applications.

[0004] In line with this, various attempts have been made to apply 5G communication systems to IoT networks. For example, technologies such as sensor networks, machine type communications (MTC), and machine-to-machine (M2M) communications can be implemented through beamforming, MIMO, and array antennas. Cloud radio access networks as an application of the above-mentioned big data processing technology can also be considered as an example of the fusion of 5G technology and IoT technology.

[0005] As described above, with the development of wireless communication systems, a method of transmitting and receiving data for network cooperative communication is required.

[0006] The above information is provided as background information only to assist in understanding the present disclosure. No determination has been made, nor has an assertion been made, as to whether any of the above content may be applied to the present disclosure as related art. Summary of the invention

[0007] Technical issues

[0008] An aspect of the present disclosure is to provide a method and apparatus for transmitting and receiving a plurality of data between a transmission node and a terminal in order to perform cooperative communication in a wireless communication system.

[0009] Solution to the problem

[0010] According to one aspect of the present disclosure, a method of a terminal is provided. The method includes receiving configuration information associated with a demodulation reference signal (DMRS) for receiving data from a base station; receiving control information including an indicator corresponding to at least one DMRS port from the base station; identifying a DMRS port assigned to the terminal based on the configuration information and the control information; and receiving data from the base station based on the identified DMRS port, wherein, in the case where the indicator corresponds to a plurality of DMRS ports, the plurality of DMRS ports include at least two DMRS ports included in different code division multiplexing (CDM) groups.

[0011] According to another aspect of the present disclosure, a method of a base station is provided. The method includes sending configuration information associated with a demodulation reference signal (DMRS) for receiving data to a terminal; sending control information including an indicator corresponding to at least one DMRS port to the terminal; identifying a DMRS port assigned to the terminal based on the configuration information and the control information; and sending data to the terminal based on the identified DMRS port, wherein, in the case where the indicator corresponds to multiple DMRS ports, the multiple DMRS ports include at least two DMRS ports included in different code division multiplexing (CDM) groups.

[0012] According to another aspect of the present disclosure, a terminal is provided. The terminal includes a transceiver and a processor, the processor being configured to receive configuration information associated with a demodulation reference signal (DMRS) for receiving data from a base station via the transceiver; receive control information including an indicator corresponding to at least one DMRS port from the base station via the transceiver; identify the DMRS port assigned to the terminal based on the configuration information and the control information; and receive data from the base station via the transceiver based on the identified DMRS port, wherein, in the case where the indicator corresponds to multiple DMRS ports, the multiple DMRS ports include at least two DMRS ports included in different code division multiplexing (CDM) groups.

[0013] According to another aspect of the present disclosure, a base station is provided. The base station includes a transceiver and a processor, the processor being configured to send configuration information associated with a demodulation reference signal (DMRS) for receiving data to a terminal via the transceiver; send control information including an indicator corresponding to at least one DMRS port to the terminal via the transceiver; identify the DMRS port assigned to the terminal based on the configuration information and the control information; and send data to the terminal based on the identified DMRS port, wherein, in the case where the indicator corresponds to multiple DMRS ports, the multiple DMRS ports include at least two DMRS ports included in different code division multiplexing (CDM) groups.

[0014] Other aspects, advantages, and salient features of the disclosure will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses various embodiments of the disclosure.

[0015] Advantageous Effects of the Invention

[0016] Aspects of the present disclosure are to solve at least the above problems and / or disadvantages and provide at least the advantages described below. Therefore, one aspect of the present disclosure is to provide a terminal and a base station capable of efficiently transmitting and receiving a plurality of data in a wireless communication system.

[0017] Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0019] Figure 1is a diagram showing a time-frequency domain transmission structure in a wireless communication system of Long Term Evolution (LTE) {Evolved Universal Terrestrial Radio Access (E-UTRA)}, LTE-Advanced (LTE-A), New Radio (NR), or the like according to an embodiment of the present disclosure;

[0020] Figure 2 is a diagram showing the structure of a frame, a subframe, and a time slot in 5G (fifth generation) according to an embodiment of the present disclosure;

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

[0022] Figure 4 is a diagram showing an example of indication and switching of a bandwidth part (BWP) in a wireless communication system according to an embodiment of the present disclosure;

[0023] Figure 5 is a diagram showing an example of a control resource set configuration in a downlink control channel in a wireless communication system according to an embodiment of the present disclosure;

[0024] Figure 6 is a diagram showing an example of physical downlink shared channel (PDSCH) frequency domain resource allocation in a wireless communication system according to an embodiment of the present disclosure;

[0025] Figure 7 is a diagram showing an example of PDSCH time domain resource allocation in a wireless communication system according to an embodiment of the present disclosure;

[0026] Figure 8 is a diagram showing an example of time domain resource allocation according to subcarrier spacings of a data channel and a control channel in a wireless communication system according to an embodiment of the present disclosure;

[0027] Fig. 9 is a diagram showing a protocol stack of a base station and a terminal in a single cell, carrier aggregation, and dual connectivity (DC) case in a wireless communication system according to an embodiment of the present disclosure;

[0028] Fig.10 is a diagram showing a method for determining whether to use a related art antenna port indication or a new antenna port indication according to an embodiment of the present disclosure;

[0029] Fig.11 is a diagram showing a method for determining whether to use a related art antenna port indication or a new antenna port indication according to an embodiment of the present disclosure;

[0030] Fig.12is a diagram showing a method for determining whether to use a related art antenna port indication or a new antenna port indication according to an embodiment of the present disclosure;

[0031] Fig.13 The structure of a terminal in a wireless communication system according to an embodiment of the present disclosure is shown;

[0032] Fig.14 shows the structure of a base station in a wireless communication system according to an embodiment of the present disclosure; and

[0033] 15A and 15B are diagrams illustrating a method for indicating an order between activated transmission configuration indication (TCI) states according to various embodiments of the present disclosure.

[0034] Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures. DETAILED DESCRIPTION

[0035] The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of the various embodiments of the present disclosure as defined by the claims and their equivalents. The following description includes various specific details that are helpful for understanding, but these are considered to be exemplary only. Therefore, it will be appreciated by those of ordinary skill in the art that various changes and modifications may be made to the various embodiments described herein without departing from the scope and spirit of the present disclosure. In addition, for the sake of clarity and conciseness, descriptions of well-known functions and structures may be omitted.

[0036] The terms and words used in the following description and claims are not limited to the bibliographical meanings, but are merely used by the inventor to enable a clear and consistent understanding of the present disclosure. Therefore, it will be clear to those skilled in the art that the following description of various embodiments of the present disclosure is provided for illustrative purposes only and not for limiting the present disclosure as defined by the appended claims and their equivalents.

[0037] It should be understood that the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a component surface" includes reference to one or more of such surfaces.

[0038] When describing the embodiments of the present disclosure, descriptions related to technical contents known in the art and not directly related to the present disclosure will be omitted. The omission of such unnecessary descriptions is intended to prevent the main idea of ​​the present disclosure from being obscured and to convey the main idea more clearly.

[0039] For the same reason, in the accompanying drawings, some elements may be enlarged, omitted or schematically shown. In addition, the size of each element does not fully reflect the actual size. In the accompanying drawings, the same or corresponding elements have the same reference numerals.

[0040] By referring to the embodiments described in detail below in conjunction with the accompanying drawings, the advantages and features of the present disclosure and the ways to achieve them will become clear. 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 attached claims. Throughout the specification, the same or similar reference numerals represent the same or similar elements.

[0041] Here, it will be understood that each block of the flowchart diagram and the combination of blocks in the flowchart diagram can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device create a component for implementing the function specified in one or more flowchart blocks. These computer program instructions can also be stored in a computer-usable or computer-readable memory, which can instruct the computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-usable or computer-readable memory produce an article including an instruction component, which implements the function specified in one or more flowchart blocks. The computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are performed on a computer or other programmable device, thereby generating a computer-implemented process, so that the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one or more flowchart blocks.

[0042] In addition, each block of the flowchart diagram may represent a module, a code segment or a code portion, which includes one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions mentioned in the blocks may not occur in order. For example, depending on the functions involved, two blocks shown in succession may actually be executed substantially simultaneously, or the blocks may sometimes be executed in reverse order.

[0043] "Unit" used herein refers to a software element or hardware element that performs a predetermined function, such as a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC). However, "unit" does not always have the meaning that is 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, processes, subroutines, program code segments, drivers, firmware, microcodes, circuits, data, databases, data structures, tables, arrays and parameters. The elements and functions provided by "unit" can be combined into fewer elements or "units" or divided into more elements or "units". In addition, elements and "units" can be implemented as one or more central processing units (CPUs) in a reproduction device or a secure multimedia card. In addition, "unit" in an embodiment can include one or more processors.

[0044] Hereinafter, the operating principle of the present disclosure will be described in detail in conjunction with the accompanying drawings. In the following description of the present disclosure, when it may make the subject matter of the present disclosure less clear, 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 differ according to the user, the user's intention or habit. Therefore, the definition of the terms. Hereinafter, a base station is an entity for performing resource allocation on 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 or a node in 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 communication functions. The base station and the terminal are not limited to the above examples. Hereinafter, the present disclosure describes a technology for a terminal to receive broadcast information from a base station in a wireless communication system. The present disclosure relates to a communication technology and a system thereof, which is used to merge a 5G (fifth generation) communication system for supporting higher data rates with IoT (Internet of Things) technology after a 4G (fourth generation) system. The present disclosure can be applied to smart services based on 5G communication technology and IoT-related technologies (e.g., smart homes, smart buildings, smart cities, smart cars or connected cars, healthcare, digital education, retail, security and safety-related services, etc.).

[0045] In the following description, for the convenience of explanation, terms related to broadcast information, terms related to control information, terms related to communication coverage, terms related to state changes (such as events), terms related to network entities, terms related to messages, terms related to device elements, etc. are illustrative words. Therefore, the present disclosure is not limited to the terms described below, and other terms with equivalent technical meanings may be used.

[0046] Hereinafter, for convenience of explanation, terms and names defined in the 3rd Generation Partnership Project Long Term Evolution (3GPP LTE) standard will be used. However, the present disclosure is not limited to the above terms and names, and can be applied to systems conforming to other standards in the same manner.

[0047] Wireless communication systems are evolving toward broadband wireless communication systems for providing high-speed and high-quality packet data services, as well as typical voice-based services, using communication standards such as 3GPP's High Speed ​​Packet Access (HSPA), LTE {Long Term Evolution or Evolved Universal Terrestrial Radio Access (E-UTRA)}, LTE-Advanced (LTE-A), LTE-Pro, 3GPP2's High Speed ​​Packet Data (HRPD), Ultra Mobile Broadband (UMB), IEEE 802.16e, etc.

[0048] 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 refers to a radio link through which a terminal {user equipment (UE) or mobile station (MS)} sends data or a control signal to a base station (BS) (eNode B), while the downlink refers to a radio link through which a base station sends data or a control signal to a terminal. The above-mentioned multiple access scheme separates the data or control information of each user by allocating and operating time-frequency resources so that the data or control information of each user is sent so as to avoid overlapping with each other (i.e., thereby establishing orthogonality).

[0049] Since the 5G communication system, which is a communication system after LTE, must freely reflect various needs of users, service providers, etc., it is necessary to support services that meet various needs. Services considered for the 5G communication system include enhanced mobile broadband (eMBB) communication, massive machine type communication (mMTC), ultra-reliable low latency communication (URLLC), etc.

[0050] According to some embodiments, eMBB is intended to provide a higher data rate than that supported by existing LTE, LTE-A or LTE-Pro. For example, in a 5G communication system, for a single base station, eMBB must provide a peak data rate of 20Gbps in the downlink and a peak data rate of 10Gbps in the uplink. In addition, eMBB must provide an increased user-perceived data rate to the terminal. In order to meet these requirements, it is necessary to improve the transmission / reception technology including further enhanced multiple-input multiple-output (MIMO) transmission technology. In addition, the data rate required by the 5G communication system can be obtained using a frequency bandwidth greater than 20MHz in a frequency band of 3 to 6GHz or 6GHz or higher, rather than using the 2GHz frequency band used in the current LTE.

[0051] In addition, mMTC is being considered to support application services such as the Internet of Things (IoT) in the 5G system. In order to effectively provide the IoT, mMTC has requirements such as supporting the connection of a large number of terminals in a cell, enhancing terminal coverage, improving battery time, and reducing terminal costs. Since the IoT provides communication functions while being provided to various sensors and various devices, it must support a large number of terminals in a cell (for example, 1,000,000 terminals / km 2 ). In addition, terminals supporting mMTC may require wider coverage than other services provided by 5G communication systems because the terminals may be located in shadow areas (such as basements of buildings) that are not covered by cells due to the nature of the service. Terminals supporting mMTC need to be configured inexpensively and may require very long battery life because it is difficult to frequently replace the battery of the terminal.

[0052] Finally, URLLC is a cellular-based mission-critical wireless communication service that is used for remote control of robots or machines, industrial automation, drones, remote healthcare, emergency alerts, etc., and must provide communications with ultra-low latency and ultra-reliability. For example, URLLC-enabled services must meet an air interface latency of less than 0.5 ms and also require 10 -5 Or lower packet error rate. Therefore, for services supporting URLLC, the 5G system must provide a shorter transmission time interval (TTI) than other services, and also requires a design for allocating a large amount of resources in the frequency band. However, the above-mentioned mMTC, URLLC and eMBB are only examples of different types of services, and the present disclosure is not limited to the above-mentioned types of services.

[0053] The above services considered in the 5G communication system must be integrated into a single framework before they can be provided. That is, for efficient resource management and control, the various services are preferably integrated into a single system to be then controlled and transmitted, rather than operating the services independently.

[0054] In addition, although the embodiments of the present disclosure will be described as LTE, LTE-A, LTE-Pro or NR systems as examples below, the embodiments of the present disclosure can be applied to other communication systems with similar technical backgrounds or channel forms. In addition, according to the judgment of those skilled in the art, without departing from the scope of the present disclosure, the embodiments of the present disclosure can be applied to other communication systems by some modifications thereof.

[0055] The present disclosure relates to a method and apparatus for repeatedly transmitting data and control signals between a plurality of transmission nodes and a terminal performing cooperative communication to improve communication reliability.

[0056] According to the present disclosure, when network cooperative communication is used in a wireless communication system, the reliability of data / control signals received by a terminal can be improved.

[0057] Hereinafter, the frame structure of the 5G system will be described in more detail with reference to the accompanying drawings.

[0058] Figure 1 2 is a diagram showing a time-frequency domain transmission structure of subframes 1-10 of an LTE, LTE-A, NR or similar wireless communication system according to an embodiment of the present disclosure.

[0059] refer to Figure 1 , Figure 1 The basic structure of the time-frequency domain as a radio resource domain for transmitting data or control channels in the 5G system is shown. Figure 1 , the horizontal axis represents the time domain, and the vertical axis represents the frequency domain. The basic unit of resources in the time-frequency domain is a resource element (RE) 1-01, which can be defined as an orthogonal frequency division multiplexing (OFDM) symbol 1-02 on the time axis and a subcarrier 1-03 on the frequency axis. Continuous N_sc^RB (e.g., 12) REs can constitute a resource block (RB) 1-04 in the frequency domain.

[0060] Figure 2 is a diagram showing a time slot structure considered in a 5G system according to an embodiment of the present disclosure.

[0061] refer to Figure 2 , Figure 2 An example of the structure of a frame 2-00, a subframe 2-01, and a time slot 2-02 is shown.

[0062] A frame 2-00 may be defined as 10 ms. A subframe 2-01 may be defined as 1 ms, and thus, a frame 2-00 may include a total of 10 subframes 2-01. A time slot 2-02 or 2-03 may be defined as 14 OFDM symbols {i.e., the number of symbols per time slot One subframe 2-01 may include one or more time slots 2-02 and 2-03, and the number of time slots 2-02 and 2-03 of each subframe 2-01 may vary depending on the configured value μ of the subcarrier spacing 2-04 or 2-05. Figure 2 The example in shows the case of μ = 0 (2-04) and the case of μ = 1 (2-05) as the configuration value of the subcarrier spacing. In the case of μ = 0 (2-04), one subframe 2-01 can include one time slot 2-02, and in the case of μ = 1 (2-05), one subframe 2-01 can include two time slots 2-03. That is, the number of time slots in each subframe is can vary depending on the configured value μ of the subcarrier spacing and the number of slots per frame It can vary depending on the configured value μ of the subcarrier spacing. and It can be defined as shown in Table 1 below.

[0063]

Table 1

[0064]

[0065] In NR, one component carrier (CC) or serving cell can include up to 250 RBs. Therefore, in the case where the terminal always receives signals through the total bandwidth of the serving cell (such as LTE), the terminal may consume a lot of power, and to solve this problem, the base station can configure one or more bandwidth parts (BWP) for the terminal so that the terminal can change the reception area in the cell.

[0066] In NR, the base station can configure the "initial BWP" for the terminal through the MIB, which is the bandwidth of the control resource set (CORESET) #0 {or the common search space (CSS)}. Thereafter, the base station can configure the initial BWP (first BWP) of the terminal through radio resource control (RRC) signaling, and can send a notification of one or more BWP configuration information that can be indicated later through downlink control information (DCI). After that, the base station can send the BWP ID through DCI, thereby indicating the frequency band to be used by the terminal. If the terminal does not receive DCI in the currently allocated BWP for a specific period of time or longer, the terminal returns to the "default BWP" and attempts to receive DCI.

[0067] Figure 3 An example of the configuration of a bandwidth part (BWP) in a wireless communication system according to an embodiment of the present disclosure is shown.

[0068] Figure 3 is a diagram showing a configuration example of a bandwidth part in a 5G communication system.

[0069] refer to Figure 3 , Figure 3 An example is shown in which UE bandwidth 3-00 is configured to have two bandwidth parts, namely bandwidth part #1 (3-05) and bandwidth part #2 (3-10). The base station can configure one or more bandwidth parts for the terminal, and can configure information about each bandwidth part, as shown in Table 2 below.

[0070]

Table 2

[0071]

[0072] In addition to the configuration information described in Table 2, various parameters related to the bandwidth part may be configured for the terminal. The base station may send the above information to the terminal through higher layer signaling (e.g., RRC). At least one configured bandwidth part may be activated. Information on whether to activate the configured bandwidth part may be semi-statically sent from the base station to the terminal through RRC signaling or dynamically sent through a MAC control element (CE) or DCI.

[0073] The configuration of the bandwidth portion supported by the above-mentioned 5G communication system can be used for various purposes.

[0074] For example, when the bandwidth supported by the terminal is less than the system bandwidth, the bandwidth supported by the terminal can be supported by configuring the bandwidth part. For example, in Table 2, the frequency position of the bandwidth part (configuration information 2) can be configured for the terminal so that the terminal can send and receive data in a specific frequency position within the system bandwidth.

[0075] As another example, for the purpose of supporting different parameter sets, the base station may configure multiple bandwidth parts for the terminal. For example, in order to support a specific terminal to send and receive data using both a subcarrier spacing of 15 kHz and a subcarrier spacing of 30 kHz, two bandwidth parts may be configured to use subcarrier spacings of 15 kHz and 30 kHz, respectively. Different bandwidth parts may be frequency-division-multiplexed (FDM), and in the case of sending and receiving data with a specific subcarrier spacing, the bandwidth part configured to the corresponding subcarrier spacing may be activated.

[0076] As another example, for the purpose of reducing the power consumption of the terminal, the base station can configure the bandwidth part with different bandwidths for the terminal. For example, if the terminal supports a very large bandwidth (e.g., a bandwidth of 100 MHz) and only sends and receives data in the corresponding bandwidth, the power consumption of the terminal may be very large. In particular, in terms of power consumption, it is very inefficient for the terminal to monitor the unnecessary downlink control channel of the large bandwidth of 100 MHz in the absence of traffic. Therefore, in order to reduce the power consumption of the terminal, the base station can configure a bandwidth part with a relatively small bandwidth for the terminal, such as a 20 MHz bandwidth part. The terminal can perform a monitoring operation in the 20 MHz bandwidth part without traffic, and if data is generated, the terminal can use the 100 MHz bandwidth part to send and receive data according to the instruction from the base station. Figure 4 is a diagram showing an example of indication and switching of bandwidth parts in a wireless communication system according to an embodiment.

[0077] Figure 4 is a diagram illustrating a method of dynamically changing a configuration of a bandwidth part according to an embodiment of the present disclosure.

[0078] refer to Figure 4 As described in Table 2 above, the base station can configure one or more bandwidth parts for the terminal, and can send information about the bandwidth of the bandwidth part, the frequency position of the bandwidth part, the parameter set of the bandwidth part, etc. to the terminal as the configuration of each bandwidth part.

[0079] Figure 4 An example is shown in which two bandwidth parts, namely, bandwidth part #1 (BPW#1) 4-05 and bandwidth part #2 (BWP#2) 4-10, are configured within a terminal bandwidth 4-00 for a terminal.

[0080] One or more bandwidth portions can be activated within the configured bandwidth and Figure 4 The example of activating a bandwidth portion will be considered in Figure 4 In the example, among the bandwidth parts configured in time slot #0 (4-25), bandwidth part #1 (4-05) is active, and the terminal can monitor a physical downlink control channel (PDCCH) in a control resource set #1 (4-45) configured in bandwidth part #1 (4-05), and can send and receive data 4-55 in bandwidth part #1 (4-05). The control resource set in which the terminal monitors the PDCCH may be different depending on the bandwidth part activated among the configured bandwidth parts, and the bandwidth in which the terminal monitors the PDCCH may vary accordingly.

[0081] The base station may also send an indicator for switching the configuration of the bandwidth part to the terminal. "Switching" the configuration of the bandwidth part may be regarded as an operation of activating a specific bandwidth part (e.g., switching the activation from bandwidth part A to bandwidth part B). The base station may send a configuration switching indicator to the terminal in a specific time slot, and the terminal may receive the configuration switching indicator from the base station, and then may apply the configuration changed according to the configuration switching indicator at a specific time to determine the bandwidth part to be activated, and may monitor the PDCCH in the control resource set configured in the activated bandwidth part.

[0082] exist Figure 4 In the example, the base station may send a configuration switching indicator 4-15 to the terminal in time slot #1 (4-30), which is used to instruct the terminal to switch the activated bandwidth part from the existing bandwidth part #1 (4-05) to the bandwidth part #2 (4-10). Upon receiving the indicator, the terminal may activate the bandwidth part #2 (4-10) according to the content of the indicator. In this case, a transition time 4-20 for switching the bandwidth part may be required, and the time for switching and applying the bandwidth part to be activated may be determined accordingly.

[0083] Figure 4 A situation is shown where one of the time slots passes a transition time 4-20 after receiving a configuration switch indicator 4-15. During the transition time 4-20 (4-60), data may not be transmitted and received. Therefore, bandwidth portion #2 (4-10) is activated in time slot #2 (4-35), so that control channels and data can be transmitted and received in the corresponding bandwidth portion.

[0084] The base station may preconfigure one or more bandwidth parts for the terminal using higher layer signaling (e.g., RRC signaling), and may indicate activation in a manner that the configuration switching indicator 4-15 is mapped to one of the bandwidth parts preconfigured by the base station. For example, a log2N bit indicator may indicate selection of one of the N preconfigured bandwidth parts.

[0085] Table 3 below shows an example of indicating configuration information on a bandwidth part using a 2-bit indicator.

[0086]

Table 3

[0087] Indicator value Bandwidth Part Configuration 00 Bandwidth configuration configured via higher layer signaling A 01 Bandwidth configuration B configured via higher layer signaling 10 Bandwidth configuration configured via higher layer signaling C 11 Bandwidth configuration configured via higher layer signaling D

[0088] Figure 4 The configuration switching indicator 4-15 for the bandwidth part described in can be transmitted from the base station to the terminal using medium access control (MAC) control element (CE) signaling or L1 signaling (eg, common DCI, group common DCI, or terminal-specific DCI).

[0089] according to Figure 4 The configuration switching indicator 4-15 for the bandwidth part described in the above description can determine the time of activation of the application to the bandwidth part as follows. The time of switching the application to the configuration can follow a predefined value (for example, the switching of the configuration is applied N (=1) time slots after receiving the configuration switching indicator), can be configured for the terminal by the base station using higher layer signaling (for example, RRC signaling), or can be partially included in the content of the configuration switching indicator 4-15 to be sent subsequently. Alternatively, the time of switching the application to the configuration can be determined by a combination of the above methods. After receiving the configuration switching indicator 4-15 for the bandwidth part, the terminal can apply the switched configuration starting from the time obtained by the above method.

[0090] Hereinafter, a downlink control channel in a 5G communication system will be described in more detail with reference to the accompanying drawings.

[0091] Figure 5 is a diagram showing an example of a control resource set configuration in a downlink control channel in a wireless communication system according to an embodiment.

[0092] Figure 5 is a diagram showing an example of a control resource set (CORESET) in a 5G wireless communication system according to an embodiment of the present disclosure, in which a downlink control channel is transmitted.

[0093] refer to Figure 5 , Figure 5 An example is shown in which two control resource sets {control resource set #1 (5-01) and control resource set #2 (5-02)} are configured in a UE bandwidth part 5-10 on the frequency axis and one time slot 5-20 on the time axis.

[0094] A control resource set 5-01 or 5-02 may be configured in a specific frequency resource 5-03 within the entire UE bandwidth portion 5-10 on the frequency axis. A control resource set 5-01 or 5-02 may be configured using one or more OFDM symbols on the time axis and may be defined as a control resource set duration 5-04. Figure 5 In the example shown, control resource set #1 (5-01) is configured to have a control resource set duration of two symbols, and control resource set #2 (5-02) is configured to have a control resource set duration of one symbol.

[0095] The control resource set in the above 5G can be configured for the terminal by the base station through higher layer signaling (e.g., system information, master information block (MIB) or radio resource control (RRC) signaling). Configuring a control resource set for a terminal means providing the terminal with information such as a control resource set identifier, a frequency position of a control resource set, a symbol duration of a control resource set, etc. For example, the information may include the items shown in Table 4.

[0096]

Table 4

[0097]

[0098] In Table 4, the "tci-StatesPDCCH" (abbreviated as "Transmission Configuration Indication (TCI) State") configuration information includes information about a channel state information reference signal (CSI-RS) index or one or more synchronization signal (SS) / physical broadcast channel (PBCH) block indices that have a QCL (quasi co-site) relationship with a demodulation reference signal (DMRS) transmitted in a corresponding control resource set.

[0099] Now, a method for allocating time and frequency resources for data transmission in NR will be described.

[0100] In addition to the frequency domain resource candidate allocation indicated by BWP, NR can also provide the following detailed frequency domain resource allocation (FD-RA) method.

[0101] Figure 6 is a diagram showing an example of PDSCH frequency domain resource allocation in a wireless communication system according to an embodiment of the present disclosure.

[0102] Figure 6 Three frequency domain resource allocation methods of Type 0 (6-00), Type 1 (6-05) and dynamic switching 6-10 are shown, which can be configured by higher layers in NR.

[0103] refer to Figure 6 , when the terminal is configured to use only resource type 0 through higher layer signaling (6-00), some downlink control information (DCI) used to allocate PDSCH to the terminal has a bitmap of NRBG bits. The conditions for this case will be described later. In this case, NRBG indicates the number of resource block groups (RGB) determined according to the size of the BWP allocated by the BWP indicator and the higher layer parameter "rgn-Size", as shown in Table 5 below, and the bitmap is used to transmit data in the RBG represented as "1".

[0104]

Table 5

[0105] Bandwidth portion size Configuration 1 Configuration 2 1-36 2 4 37-72 4 8 73-144 8 16 145-275 16 16

[0106] In the case where the terminal is configured to use only resource type 1 through higher layer signaling (6-05), a certain DCI for allocating PDSCH to the terminal has a The base station may configure the start VRB 6-20 and the length 6-25 of the subsequent frequency domain resources.

[0107] If the terminal is configured to use resource type 0 and resource type 1 through higher layer signaling (6-10), a certain DCI for allocating PDSCH to the corresponding terminal has frequency domain resource allocation information, which includes a bit of a larger value 6-35 among payload 6-20 and 6-25 for configuring resource type 0 and a payload 6-15 for configuring resource type 1. The conditions for this case will be described again later. In this case, one bit can be added to the frontmost part (MSB) of the frequency domain resource allocation information in the DCI, and bit 0 indicates the use of resource type 0, while bit 1 indicates the use of resource type 1.

[0108] Figure 7 is a diagram showing an example of PDSCH time domain resource allocation in a wireless communication system according to an embodiment of the present disclosure.

[0109] refer to Figure 7 , the base station can use the subcarrier spacing (SCS) (μ PDSCH and μ PDCCH ), a predetermined time slot offset (K0), the starting position 7-00 of an OFDM symbol in a time slot dynamically indicated by DCI, and its length 7-05 to indicate the time domain position of the PDSCH resource.

[0110] Figure 8 is a diagram showing an example of time domain resource allocation according to subcarrier spacings of a data channel and a control channel in a wireless communication system according to an embodiment of the present disclosure.

[0111] refer to Figure 8 , if the subcarrier spacing of the data channel is the same as that of the control channel (μ PDSCH =μ PDCCH )(8-00), the time slot numbers used for data and control are the same. Therefore, the base station and the terminal can identify the occurrence of scheduling offset according to the predetermined time slot offset (K0).

[0112] On the other hand, if the subcarrier spacing of the data channel is different from the subcarrier spacing of the control channel (μ PDSCH ≠μ PDCCH)(8-05), the time slot numbers used for data and control are different from each other. Therefore, the base station and the terminal can identify the occurrence of scheduling offset based on the subcarrier spacing of the PDCCH and according to the predetermined time slot offset (K0).

[0113] As shown in Table 6 below, NR provides various types of DCI formats so that the terminal can effectively receive the control channel.

[0114]

Table 6

[0115]

[0116] For example, the base station may use DCI format 0_0 or DCI format 0_1 ​​in order to schedule the PDSCH for a single cell.

[0117] In case that DCI format 0_1 ​​is transmitted together with a CRC scrambled by a cell radio network temporary identifier (C-RNTI), a configured scheduling RNTI (CS-RNTI), or a new RNTI, DCI format 0_1 ​​includes at least the following information.

[0118] - Identifier of DCI format (1 bit): This is a DCI format indicator, which is always configured to "1".

[0119] - Frequency domain resource allocation (NRBG bits or bits): This indicates the frequency domain resource allocation and if DCI format 1_0 is monitored in the UE-specific search space, then Indicates the size of the active DLBWP. Otherwise, Indicates the size of the initial DL BWP. NRBG is the number of resource block groups. See frequency domain resource allocation above for details.

[0120] - Time domain resource allocation (0 to 4 bits): This indicates the time domain resource allocation according to the above description.

[0121] - VRB-to-PRB mapping (1 bit): "0" indicates non-interleaved VRB-to-PRB mapping, and "1" indicates interleaved VRB-to-PRB mapping.

[0122] - Modulation and coding scheme (5 bits): This indicates the modulation order and coding rate used in PDSCH transmission.

[0123] - New data indicator (1 bit): This indicates whether the PDSCH corresponds to an initial transmission or a retransmission according to toggling.

[0124] - Redundancy version (2 bits): This indicates the redundancy version used for PDSCH transmission.

[0125] - HARQ process number (4 bits): This indicates the HARQ process number used in PDSCH transmission.

[0126] - Downlink Allocation Index (2 bits): This is the DAI indicator.

[0127] - TPC command for scheduled PUCCH (2 bits): This is the PUCCH power control indicator

[0128] - PUCCH resource indicator (3 bits): This is a PUCCH resource indicator, and indicates that one of eight resources configured by a higher layer is used.

[0129] - PDSCH-to-HARQ_feedback timing indicator (3 bits): This is a HARQ feedback timing indicator and indicates one of eight feedback timing offsets configured using a higher layer.

[0130] In case that DCI format 1_1 is transmitted together with a CRC scrambled by a cell radio network temporary identifier (C-RNTI), a configured scheduling RNTI (CS-RNTI), or a new RNTI, DCI format 1_1 includes at least the following information.

[0131] - Identifier of DCI format (1 bit): This is a DCI format indicator, which is always configured to "1".

[0132] - Carrier indicator (0 or 3 bits): This indicates the CC (or cell) transmitting the PDSCH allocated by the corresponding DCI.

[0133] - Bandwidth part indicator (0, 1 or 2 bits): This indicates the BWP over which the PDSCH allocated by the corresponding DCI is transmitted.

[0134] - Frequency domain resource allocation (payload is determined according to frequency domain resource allocation): This indicates the frequency domain resource allocation, and Indicates the size of the active DL BWP. See frequency domain resource allocation for details.

[0135] - Time domain resource allocation (0 to 4 bits): This indicates the time domain resource allocation according to the above description.

[0136] - VRB-to-PRB mapping (0 or 1 bit): "0" indicates non-interleaved VRB-to-PRB mapping, and "1" indicates interleaved VRB-to-PRB mapping. In case frequency domain resource allocation is configured as resource type 0, this is 0 bit.

[0137] -PRB bundling size indicator (0 or 1 bit): This is 0 bit if the higher layer parameter "prb-BundlingType" is not configured or is configured as "static"; this is 1 bit if the higher layer parameter "prb-BundlingType" is configured as "dynamic".

[0138] - Rate matching indicator (0 or 1 or 2 bits): This indicates the rate matching mode.

[0139] - ZP CSI-RS trigger (0 or 1 or 2 bits): This is an indicator for triggering aperiodic ZP CSI-RS.

[0140] For transport block 1:

[0141] - Modulation and coding scheme (5 bits): This indicates the modulation order and coding rate used for PDSCH transmission.

[0142] - New Data Indicator (1 bit): This indicates whether the PDSCH corresponds to an initial transmission or a retransmission according to the toggle.

[0143] - Redundancy version (2 bits): This indicates the redundancy version used in PDSCH transmission.

[0144] For transport block 2:

[0145] - Modulation and coding scheme (5 bits): This indicates the modulation order and coding rate used for PDSCH transmission.

[0146] - New Data Indicator (1 bit): This indicates whether the PDSCH corresponds to an initial transmission or a retransmission according to the toggle.

[0147] - Redundancy version (2 bits): This indicates the redundancy version used in PDSCH transmission.

[0148] - HARQ process number (4 bits): This indicates the HARQ process number used for PDSCH transmission.

[0149] - Downlink Allocation Index (0, 2 or 4 bits): This is the DAI indicator.

[0150] - TPC command for scheduled PUCCH (2 bits): This is the PUCCH power control indicator

[0151] - PUCCH resource indicator (3 bits): This is a PUCCH resource indicator, and indicates that one of eight resources configured by a higher layer is used.

[0152] - PDSCH-to-HARQ_feedback timing indicator (3 bits): This is a HARQ feedback timing indicator and indicates one of eight feedback timing offsets configured using a higher layer.

[0153] - Antenna port (4, 5 or 6 bits): This indicates the DMRS port and the code division multiplexed (CDM) group without data.

[0154] -Transmission Configuration Indication (0 or 3 bits): TCI indicator.

[0155] -SRS request (2 or 3 bits): SRS transmission request indicator

[0156] -CBG transmission information (0, 2, 4, 6 or 8 bits): This is an indicator indicating whether a code block group is transmitted in the allocated PDSCH. "0" indicates that the corresponding CBG is not transmitted, and "1" indicates that the corresponding CBG is transmitted.

[0157] -CBG flushing out information (0 or 1 bit): This is an indicator indicating whether the previous CBG is contaminated. "0" indicates that the previous CBG may be contaminated, while "1" indicates that the previous CBG is combinable when receiving a retransmission.

[0158] -DMRS sequence initialization (0 or 1 bit): DMRS scrambling ID selection indicator

[0159] The number of DCIs with different sizes that the terminal can receive for each time slot in the corresponding cell is at most 4. The number of DCIs with different sizes that the terminal can receive for each time slot in the corresponding cell and that are scrambled by the C-RNTI is at most 3. Here, the antenna port indication can be indicated by the following Tables 7 to 10.

[0160] [Table 7] Antenna port (1000+DMRS port), dmrs-Type=1, maxLength=1

[0161]

[0162]

[0163] [Table 8] Antenna port (1000+DMRS port), dmrs-Type=1, maxLength=2

[0164]

[0165]

[0166] [Table 9] Antenna port (1000+DMRS port), dmrs-Type=2, maxLength=1

[0167]

[0168]

[0169] [Table 10] Antenna port (1000+DMRS port), dmrs-Type=2, maxLength=2

[0170]

[0171]

[0172]

[0173] Table 7 is used when "dmrs-type" is indicated as 1 and "maxLength" is indicated as 1, and Table 8 is used when "dmrs-type" = 1 and "maxLength" = 2. In addition, when "dmrs-type" = 2 and "maxLength" = 1, Table 9 is used to indicate the port of the DMRS to be used, and when "dmrs-type" = 2 and "maxLength" = 2, Table 10 is used to indicate the port of the DMRS to be used. The numbers 1, 2, and 3 indicated by the "number of DMRS CDM groups without data" in these tables represent CDM groups {0}, {0, 1}, and {0, 1, 2}, respectively. "DMRS port" shows the indexes of the used ports arranged in sequence. The antenna port is indicated as "DMRS port + 1000". The CDM group (CDM group) of DMRS is associated with the method of generating a DMRS sequence and the antenna port, as shown in Tables 11 and 12. Table 11 shows parameters when 'dmrs-type'=1, and Table 12 shows parameters when 'dmrs-type'=2.

[0174] [Table 11] Parameters for PDSCH DM-RS dmrs-type = 1

[0175]

[0176] [Table 12] Parameters for PDSCH DM-RS dmrs-type = 2

[0177]

[0178] A sequence of a DMRS according to various parameters is determined using Equation 1 below.

[0179]

[0180] k′=0,1

[0181]

[0182] n=0,1,…

[0183] …Equation 1

[0184] If only one codeword is enabled in Tables 7 and 8, rows 2, 9, 10, 11, and 30 are only used for single-user MIMO. That is, in this case, the terminal may not perform multi-user MIMO reception operations such as cancelling, nulling, or whitening multi-user interference without assuming that another terminal is co-scheduled.

[0185] If only one codeword is enabled in Tables 9 and 10, rows 2, 10, and 23 are only used for single-user MIMO. That is, in this case, the terminal may not perform multi-user MIMO reception operations such as canceling, nulling, or whitening multi-user interference without assuming that another terminal is co-scheduled.

[0186] Fig. 9 2 are diagrams showing radio protocol structures of a base station and a terminal in cases of a single cell, carrier aggregation, and dual connectivity, respectively, according to an embodiment of the present disclosure.

[0187] refer to Fig. 9 The radio protocols of the next-generation mobile communication system include NR Service Data Adaptation Protocol (SDAP) 9-25 or 9-70, NR Packet Data Convergence Protocol (PDCP) 9-30 or 9-65, NR Radio Link Control (RLC) 9-35 or 9-60, and NR Medium Access Control (MAC) 9-40 or 9-55 in the terminal and NR base station, respectively.

[0188] The main functions of SDAP NR 9-25 or 9-70 may include some of the following functions.

[0189] -Transmission of user plane data

[0190] - Mapping between QoS flows and DRBs for DL ​​and UL

[0191] - Marking of QoS Flow ID in both DL and UL packets

[0192] - Mapping of Reflective QoS Flows to DRBs for UL SDAP PDUs

[0193] Regarding the SDAP layer entity, the terminal may receive a configuration through an RRC message, which indicates whether to use the header of the SDAP layer entity for each PDCP layer entity, for each bearer or for each logical channel, or whether to use the function of the SDAP layer entity. When the SDAP header is configured, the 1-bit NAS reflection QoS configuration indicator and the 1-bit AS reflection QoS configuration indicator of the SDAP header may indicate that the terminal updates or reconfigures the mapping information between the QoS flow and the data bearers in the uplink and downlink. The SDAP header may include QoS flow ID information indicating QoS. QoS information can be used as data processing priority, scheduling information, etc. to support effective services.

[0194] The main functions of PDCP NR 9-30 or 9-65 may include some of the following functions.

[0195] -Header compression and decompression (ROHC only)

[0196] -Transmission of user data

[0197] - In-sequence delivery of upper layer PDUs

[0198] - Out-of-order delivery of upper layer PDUs

[0199] -Sequence reordering (PDCP PDU reordering for reception)

[0200] - Duplicate detection of lower layer SDU

[0201] -Retransmission of PDCP SDU

[0202] -Encryption and decryption

[0203] - Timer-based SDU discard in uplink

[0204] The above-mentioned reordering function of the NR PDCP entity represents a function of reordering the PDCP PDU received from the lower layer based on the PDCP sequence number (SN), which may include a function of sending data to a higher layer in the reordered order, a function of directly sending data regardless of the order, a function of reordering the sequence and recording the lost PDCP PDU, a function of sending a status report of the lost PDCP PDU to the transmitting end, and a function of requesting retransmission of the lost PDCP PDU.

[0205] The main functions of RLC NR 9-35 or 9-60 may include some of the following functions.

[0206] -Data transmission function (transmission of upper layer PDU)

[0207] - In-sequence delivery of upper layer PDUs

[0208] - Out-of-order delivery of upper layer PDUs

[0209] -ARQ function (error correction through ARQ)

[0210] - Concatenation, segmentation and reassembly of RLC SDUs

[0211] - Re-segmentation of RLC data PDUs

[0212] - Reordering of RLC data PDUs

[0213] - Duplicate detection

[0214] -Protocol error detection

[0215] -RLC SDU discarded

[0216] -RLC reconstruction

[0217] The above-mentioned in-sequence delivery function of the NR RLC entity means a function of transmitting the RLC SDU received from the lower layer to the higher layer in sequence, which may include a function of reassembling and sending the reassembled RLC SDU if an original RLC SDU is divided into multiple RLC SDUs and received, a function of reordering the received RLC SDU based on the RLC sequence number (SN) or the PDCP sequence number (SN), a function of reordering the sequence and recording the lost RLC PDU, a function of sending a status report of the lost RLC PDU to the transmitting end, a function of requesting retransmission of the lost RLC PDU, a function of sending only the RLC SDU before the lost RLC SDU in sequence to the higher layer if there is a lost RLC SDU, a function of sending all RLC SDUs received before the start of the timer in sequence to the higher layer even if there is a lost RLC SDU if a predetermined timer expires, or a function of sending all RLC SDUs received until now in sequence to the higher layer even if there is a lost RLC SDU if a predetermined timer expires. In addition, the RLC PDU may be processed in the order of reception (in the order of arrival, regardless of its sequence number or sequence number), and the RLC PDU may be sent to the PDCP entity in an out-of-order delivery manner. In the case of segmentation, segments stored in a buffer or to be received later may be received and reconfigured into a complete RLC PDU, and the RLC PDU may be processed and sent to the PDCP entity. The NR RLC layer may not include a cascading function, which may be performed in the NR MAC layer or may be replaced by a multiplexing function of the NR MAC layer.

[0218] Out-of-order delivery of the NR RLC entity means a function of sending the RLC SDU received from the lower layer directly to the higher layer without considering the order, which may include the function of reassembling and sending the reassembled RLC SDU if an original RLC SDU is divided into multiple RLC SDUs and received, and may include the function of storing and sorting the RLC SN or PDCP SN of the received RLC PDU, thereby recording the lost RLC PDU.

[0219] NR MAC 9-40 or 9-55 can be connected to multiple NR RLC entities configured in a single terminal, and the main functions of NR MAC may include some of the following functions.

[0220] - Mapping between logical channels and transport channels

[0221] -Multiplexing / demultiplexing of MAC SDU

[0222] -Dispatch information report

[0223] -HARQ function (error correction through HARQ)

[0224] - Priority handling between logical channels of a UE

[0225] - Prioritization between UEs through dynamic scheduling

[0226] -MBMS service logo

[0227] -Transmission format selection

[0228] -filling

[0229] The NR PHY layers 9-45 and 9-50 may perform operations of channel encoding and modulating higher layer data into OFDM symbols and transmitting through a radio channel, or demodulating and channel decoding OFDM symbols received through a radio channel and transmitting the decoded OFDM symbols to a higher layer.

[0230] The detailed structure of the radio protocol can be changed in various ways according to the carrier (or cell) operation scheme. For example, when the base station sends data to the terminal based on a single carrier (or cell), the base station and the terminal use a single protocol structure for each layer, as shown in 9-00.

[0231] On the other hand, in the case where the base station sends data to the terminal based on carrier aggregation (CA) using multiple carriers in a single TRP, the base station and the terminal use a protocol structure in which a single structure is provided until the RLC layer and the PHY layer are multiplexed through the MAC layer, as shown in 9-10.

[0232] As another example, in the case where the base station sends data to the terminal based on dual connectivity (DC) using multiple carriers in multiple TRPs, the base station and the terminal use a protocol structure in which a single structure is provided until the RLC layer and the PHY layer are multiplexed through the MAC layer, as shown in 9-20.

[0233] In LTE and NR, the terminal has a process of reporting the capabilities supported by the terminal to the corresponding base station while being connected to the serving base station, which will be referred to as "UE capabilities (reporting)" in the following description.

[0234] The base station may send a UE capability query message requesting a capability report to a terminal in a connected state. The message may include a request from the base station for the terminal capability of each RAT type. The request for each RAT type may include information about the requested frequency band. In addition, a UE capability query message may be sent while requesting multiple RAT types through a single RRC message container, or may include multiple UE capability query messages containing requests for each RAT type, and then send them to the terminal. That is, the UE capability query may be repeated multiple times, and the terminal may configure a corresponding UE capability information message, and may report it multiple times. In the next generation mobile communication system, requests for terminal capabilities may be performed for MR-DC as well as NR, LTE and EN-DC. For reference, the UE capability query message is generally sent in the initial stage after the terminal is connected, but the base station is able to request UE capabilities under any conditions as needed.

[0235] In the above steps, the terminal that receives the request to report UE capabilities from the base station configures the terminal capabilities according to the RAT type and frequency band information requested by the base station. The following summarizes the method for configuring UE capabilities by the terminal in the NR system.

[0236] 1. If the terminal receives a list of LTE and / or NR bands through a UE capability request from a base station, the terminal configures a band combination (BC) for EN-DC and NR standalone (SA). In other words, the terminal configures a candidate list of BCs for EN-DC and NR-SA based on the bands requested by the base station using "FreqBandList". In addition, the bands have priorities in the order described in "FreqBandList".

[0237] 2. If the base station requests UE capability reporting by setting the "eutra-nr-only" flag or the "eutra" flag, the terminal completely removes the NR SA BC from the configured BC candidate list. This operation can only be performed when the LTE base station (eNB) requests the "eutra" capability.

[0238] 3. Thereafter, the terminal removes the fallback BC from the BC candidate list configured in the above step. The fallback BC corresponds to the case where the frequency band corresponding to at least one SCell is removed from a specific superset BC, and the fallback BC can be omitted because the super-configured BC can cover the fallback BC. This step is also applied to MR-DC, i.e., the LTE band. The remaining BCs after this step constitute the final "candidate BC list".

[0239] 4. The terminal selects the BC to be reported that meets the requested RAT type from the final "candidate BC list". In this step, the terminal configures the "supportedBandCombinationList" in a predetermined order. In other words, the terminal configures the BC and UE capabilities to be reported in the order of the pre-configured RAT types (nr→eutra-nr→eutra). In addition, the terminal configures the "featureSetCombination" for the configured "supportedBandCombinationList" and configures the "candidate feature set combination" list based on the candidate BC list from which the fallback BC list (including capabilities of equal or lower levels) is removed. The "candidate feature set combination" may include feature set combinations of BCs for both NR and EUTRA-NR, and may be obtained from the feature set combinations of the "UE-NR-Capabilities" and "UE-MRDC-Capabilities" containers.

[0240] 5. In addition, if the requested RAT type is "eutra-nr" and it has an impact, "featureSetCombinations" is included in both containers of "UE-MRDC-Capabilities" and "UE-NR-Capabilities". However, the feature set of NR is only included in "UE-NR-Capabilities".

[0241] After configuring the terminal capabilities, the terminal can send a UE capability information message including the UE capabilities to the base station. Then, the base station performs appropriate scheduling and transmission / reception management for the terminal based on the UE capabilities received from the terminal.

[0242] For the convenience of the following description, Tables 7 to 10 will be referred to as “first antenna port indication (or antenna port indication of the related technology)”, and the table obtained by modifying some or all of the code points in Tables 7 to 10 will be referred to as “second antenna port indication (new antenna port indication)”.

[0243] In order to support non-coherent joint transmission (NC-JT) that provides data to the terminal at one or more transmission points at the same time, it is necessary to 1) allocate PDSCHs sent at two (or more) different transmission points through a single PDCCH, or 2) allocate PDSCHs sent at two or more different transmission points through multiple PDCCHs. The terminal is able to obtain the QCL connection relationship between each reference signal or between each channel based on L1 / L2 / L3 signaling, and effectively estimate the large-scale parameters of each reference signal or channel accordingly. If the transmission points of a specific reference signal or channel are different, it is difficult for the large-scale parameters to be shared with each other. Therefore, when performing cooperative transmission, the base station needs to simultaneously notify the terminal of quasi-co-location information about two or more transmission points through two or more TCI states. If non-coherent cooperative transmission is supported by multiple PDCCHs, that is, if two or more PDCCHs simultaneously allocate two or more PDSCHs to the same serving cell and the same bandwidth part, two or more TCI states can be allocated to each PDSCH or DMRS port through each PDCCH. On the other hand, if non-coherent cooperative transmission is supported by a single PDCCH, that is, if one PDCCH simultaneously allocates two or more PDSCHs to the same serving cell and the same bandwidth part, two or more TCI states must be allocated to each PDSCH or DMRS port through a single PDCCH.

[0244] If it is assumed that the DMRS ports assigned to the terminal are divided into a DMRS port group A transmitted at a transmission point A at a specific time and a DMRS port group B transmitted at a transmission point B, two or more TCI states can be connected to the corresponding DMRS port groups to estimate the channel based on different QCL assumptions of the corresponding groups. At the same time, different DMRS ports can be code division multiplexed (CDM), frequency division multiplexed (FDM), or time domain multiplexed (TDM) to increase channel measurement accuracy and reduce transmission burden. If, among the above-mentioned DMRS ports, the DMRS ports to be multiplexed using CDM are collectively referred to as "CDM groups", it may be important to ensure that the DMRS ports existing in the same CDM group do not have different TCI states, because when the DMRS ports in the CDM group have similar channel characteristics for each port, code-based multiplexing is performed well (that is, when the channel characteristics of each port are similar, it is easy to perform distinction using an orthogonal cover code (OCC)). The present disclosure provides a method for indicating DMRS ports and CDM groups without data to a terminal so as to meet the above characteristics.

[0245] Hereinafter, for convenience of explanation, allocation of a DMRS port and a CDM group having no data will be referred to as "DMRS allocation".

[0246] With reference to the first antenna port indication shown in Tables 7 to 10 (hereinafter referred to as "antenna port indication of the related art"), it can be seen that some of the code points that can be used for NC-JT (i.e., points for allocating two or more DMRS) do not satisfy the DMRS allocation conditions for NC-JT (i.e., the condition that DMRS ports existing in the same CDM group do not have different TCI states from each other). For example, in the case of using a single codeword in Table 9, it can be seen that some rows {2, 7, 8, 17, 18, 19} of the rows {2, 7, 8, 9, 10, 17, 18, 19, 20, 21, 22, 23} that allocate two or more DMRS ports are allocated one of the DMRS port pairs {0, 1}, {2, 3}, and {4, 5}, and according to Table 12, the DMRS port pair belongs to a single CDM group. This means that rows {2, 7, 8, 17, 18, 19} are not suitable for DMRS allocation for NC-JT in Table 9. This makes it impossible to use approximately half of the possible code points and requires changes to the antenna port indication of the related art.

[0247] In the above description, "allocating" DMRS ports and CDM groups for NC-JT can be understood as: allocating DMRS ports and CDM groups through various methods (such as the size of DCI, the payload of specific fields in DCI, and the RNTI type used for CRC scrambling of the PDCCH including the DCI) when the terminal recognizes that two or more PDSCHs can be allocated to the same service cell and the same bandwidth part using one PDCCH (or two or more DMRS port groups or the allocated TCI code points are associated with two or more TCI states).

[0248] Similar to the above description, in the case of using a single codeword in Table 7, it can be seen that some rows {2, 7, 8} in the rows {2, 7, 8, 9, 10, 11} that allocate two or more DMRS ports are allocated one of the DMRS port pairs {0, 1} and {2, 3}, and the DMRS port pair belongs to a single CDM group according to Table 11. This means that row {2, 7, 8} is not suitable for DMRS allocation for NC-JT in Table 9.

[0249] Similar to the description above, in the case of using a single codeword in Table 8, it can be seen that some of the rows {2, 7, 8, 9, 10, 11, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30} that allocate two or more DMRS ports are allocated one of the DMRS port pairs {0, 1}, {2, 3}, {0, 4}, {2, 6}, {0, 1, 4}, {2, 3, 6}, {0, 1, 4, 5} and {2, 3, 6, 7}, and according to Table 11, the DMRS port pair belongs to a single CDM group. This means that rows {2, 7, 8, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29} are not suitable for DMRS allocation in Table 9 for NC-JT.

[0250] Similar to the above description, in the case of using a single codeword in Table 10, it can be seen that some rows {2, 7, 8, 17 to 23, 36 to 47, 52} in the rows {2, 7, 8, 17 to 19, 36 to 47, 52} that allocate two or more DMRS ports allocate a subset of DMRS port pairs {0, 1, 6, 7}, {2, 3, 8, 9}, and {4, 5, 10, 11}, and according to Table 12, the DMRS port pairs belong to a single CDM group. This means that rows {2, 7, 8, 17 to 19, 36 to 47, 52} are not suitable for DMRS allocation for NC-JT in Table 10.

[0251] The following embodiments provide a method for performing a second antenna port indication (hereinafter referred to as "new antenna port indication") by modifying some or all code points of the antenna port indication of the related technology, and a method for selecting one of the antenna port indication of the related technology and the new antenna port indication based on the above method.

[0252] First embodiment: New antenna port indication method 1

[0253] The first embodiment proposes a method for performing new antenna port indication by correcting the code point having the problem in the antenna port indication of the above related art.

[0254] As one of the methods for solving the above problem, the DMRS ports indicated under a specific condition may be divided into two or more groups, and the values ​​of the DMRS ports belonging to the second group may be modified through a specific operation.

[0255] The above-mentioned specific conditions may be at least one of 1) the number of DMRS CDM groups indicated by the antenna port indication is 2 or more, 2) the number of DMRS ports indicated by the antenna port indication is 2 or more, and 3) the number of codewords indicated by the antenna port indication is 2 or more, or may be a combination thereof (for example, the case where both conditions 1 and 2 are met).

[0256] Dividing the DMRS ports into two or more groups may be, for example, dividing the DMRS ports into two or more groups having an equal number of DMRS ports based on the DMRS port numbers assigned to the respective DMRS ports (in the case where the DMRS ports cannot be divided into an equal number of DMRS ports, the DMRS ports may be divided such that the last group has a smaller number of DMRS ports or such that any one group has a smaller number of DMRS ports).

[0257] The specific operation may be adding or subtracting a specific value X (e.g., X=1 or 2) (which is predetermined or configured by higher layer signaling). Alternatively, the specific operation may be a modulo operation so that the value obtained by adding the value X does not exceed a specific range (e.g., the maximum DMRS port number that can be indicated by the corresponding antenna port indication).

[0258] The method of changing the second half of the DMRS port set indicated by the problematic code point among the antenna port indication code points of the related art using the rule "(the second half of the DMRS port set + 2)% maximum DMRS port" can be regarded as a method of performing configuration so that DMRS ports associated with different TCI states are transmitted in different CDM groups. This can be expressed in detail as the following Tables 13-1 to 13-4.

[0259] For example, referring to Table 13-1, if the existing DMRS ports are 0 and 1, the DMRS port 1 corresponding to the second half may be changed to (1+2)%4=3.

[0260] For example, referring to Table 13-2, if the existing DMRS ports are 0, 1, 4, and 5, the DMRS ports 4 and 5 corresponding to the second half may be changed to 6 and 7 by applying the same equation.

[0261] The same principle is applied to Tables 13-3 and 13-4, and if three DMRS ports are used, the first half represents the first two DMRS ports and the second half represents the third DMRS port. The changed port index can be used when sorted in the order of small indexes or not. The method of indicating the changed code point may include a method of pre-storing the changed code point in the memory of the terminal and then using the changed code point, a method of updating the value of each code point through RRC, and a method of using RRC to indicate the change rule actually used among one or more change rules.

[0262] [Table 13-1] DMRS indication table for antenna port (1000+DMRS port), dmrs-Type=1, maxLength=1

[0263]

[0264]

[0265] [Table 13-2] DMRS indication table for antenna port (1000+DMRS port), dmrs-Type=1, maxLength=2

[0266]

[0267]

[0268]

[0269] [Table 13-3] DMRS indication table for antenna port (1000+DMRS port), dmrs-Type=2, maxLength=1

[0270]

[0271]

[0272] [Table 13-4] DMRS indication table for antenna port (1000+DMRS port), dmrs-Type=2, maxLength=2

[0273]

[0274]

[0275]

[0276]

[0277] The method of changing the second half of the DMRS port set indicated by the problematic code point among the antenna port indication code points of the related art using the rule of "the second half of the DMRS port set + 2", and if the value is negative, adding the maximum DMRS port, can be regarded as another method of performing configuration so that DMRS ports associated with different TCI states are transmitted in different CDM groups. This can be expressed in detail as the following Tables 14-1 to 14-4.

[0278] For example, if the existing DMRS ports are 0 and 1 in Table 14-1, DMRS port 1 corresponding to the second half may be changed to (1-2)=-1, and since the value is negative, it may be changed to -1+4=3.

[0279] For example, in Table 14-2, if the existing DMRS ports at the existing code point 29 are 0, 2, 6, and 7, the DMRS ports 6 and 7 corresponding to the latter half may be changed to 4 and 5 by applying the same equation.

[0280] The same principle is applied to Tables 14-3 and 14-4. If three DMRS ports are used, the first half indicates the first two DMRS ports and the second half indicates the third DMRS port. The port index according to the change can be used in the order of small index or without sorting. The method of indicating the changed code point may include a method of pre-storing the changed code point in the memory of the terminal and then using the changed code point, a method of updating the value of each code point through RRC, and a method of using RRC to indicate the change rule actually used among one or more change rules.

[0281] [Table 14-1] DMRS indication table for antenna port (1000+DMRS port), dmrs-Type=1, maxLength=1

[0282]

[0283]

[0284] [Table 14-2] DMRS indication table for antenna port (1000+DMRS port), dmrs-Type=1, maxLength=2

[0285]

[0286]

[0287]

[0288] [Table 14-3] DMRS indication table for antenna port (1000+DMRS port), dmrs-Type=2, maxLength=1

[0289]

[0290]

[0291] [Table 14-4] DMRS indication table for antenna port (1000+DMRS port), dmrs-Type=2, maxLength=2

[0292]

[0293]

[0294]

[0295]

[0296] Second embodiment: New antenna port indication method 2

[0297] The second embodiment proposes a method for further supporting antenna port indication for NC-JT transmission while maintaining the code point indicated by the antenna port indication of the related art so as to maintain compatibility with the terminal in the network of the related art. The antenna port indication of the related art does not support some of the DMRS port allocations for NC-JT. For example, the antenna port indication of the related art does not support the code point for allocating one DMRS port to CDM group 0 and allocating two DMRS ports to CDM group 1. 1) If two or more TCI states are indicated, 2) If reordering of the indicated TCI states is not supported (for example, {TCI state A, TCI state B} is supported, but {TCI state B, TCI state A} is not supported, and 3) If the connection relationship between the TCI state and the CDM group is configured as static / semi-static (for example, the connection is performed as TCI state A→CDM group 0 and TCI state B→CDM group 1), it is not supported to allocate one DMRS port to TRPA corresponding to TCI state A and allocate two DMRS ports to TRP B corresponding to TCI state B.

[0298] As a first method for supporting DMRS port allocation according to the above-mentioned second embodiment, a previously unused code point indicated as reserved in the antenna port indication of the related art can be used as an additional code point for NC-JT. The port allocation indicated by the additional code point for NC-JT can be a combination of the number of antenna ports of each TRP that is not supported by the antenna port indication of the related art. This can be expressed in detail as shown in Tables 15-1 to 15-4-2 below.

[0299] For example, referring to Table 15-1, code point 12 previously indicated as reserved may be switched to a code point that allocates one DMRS port to CDM group 0 and two DMRS ports to CDM group 1. A similar principle may be used for Table 15-2.

[0300] [Table 15-1] DMRS indication table for antenna port (1000+DMRS port), dmrs-Type=1, maxLength=1

[0301]

[0302]

[0303] [Table 15-2] DMRS indication table for antenna port (1000+DMRS port), dmrs-Type=1, maxLength=2

[0304]

[0305]

[0306]

[0307] At the same time, the following two situations are considered in Table 15-3-1 and Table 15-3-2.

[0308] 1) Table 15-3-1: When TRP A is connected to CDM group 0 and TRP B is connected to CDM groups 1 and 2, code points of (a) one DMRS port is allocated to TRP A and two DMRS ports are allocated to TRP B and (b) one DMRS port is allocated to TRP A and three DMRS ports are allocated to TRP B. Depending on the channel characteristics between TRP terminals, etc., some of the code points can be omitted. For example, the average channel gain from each TRP to the terminal may have similar characteristics, so the channel rank from each TRP to the terminal may be similar. In this case, the code point of (b) having a relatively large difference in the number of DMRS ports between the two TRPs can be omitted.

[0309] 2) Table 15-3-2: In the case where TRP A is connected to CDM groups 0 and 1 and TRP B is connected to CDM group 2, all code points of (a) one DMRS port is allocated to TRP A and two DMRS ports are allocated to TRP B, (b) two DMRS ports are allocated to TRP A and TRP B respectively, and (c) one DMRS port is allocated to TRP A and three DMRS ports are allocated to TRP B. Some of the code points can be omitted according to the channel characteristics between the TRP terminals, etc. For example, the average channel gain from each TRP to the terminal may have similar characteristics, so the channel rank from each TRP to the terminal may be similar. In this case, the code point of (c) having a relatively large difference in the number of DMRS ports between the two TRPs can be omitted.

[0310] Tables 15-4-1 and 15-4-2 also adopt similar principles to Tables 15-3-1 and 15-3-2 respectively.

[0311] [Table 15-3-1] DMRS indication table of antenna port (1000+DMRS port), dmrs-Type=2, maxLength=1

[0312]

[0313]

[0314]

[0315] [Table 15-3-2] DMRS indication table for antenna port (1000+DMRS port), dmrs-Type=2, maxLength=1

[0316]

[0317]

[0318]

[0319] [Table 15-4-1] DMRS indication table for antenna port (1000+DMRS port), dmrs-Type=2, maxLength=2

[0320]

[0321]

[0322]

[0323]

[0324] [Table 15-4-2] DMRS indication table for antenna port (1000+DMRS port), dmrs-Type=2, maxLength=2

[0325]

[0326]

[0327]

[0328]

[0329] As a second method for supporting DMRS port allocation according to the second embodiment described above, the base station may indicate the order of TCI states to be activated. For example, the base station may indicate {TCI state A, TCI state B} and {TCI state B, TCI state A} so that the terminal can distinguish them. To this end, two methods may be considered, as will be described in Figures 15A and 15B.

[0330] FIG. 15A illustrates a method for indicating an order between TCI states according to Method 1 according to an embodiment of the present disclosure.

[0331] 15A , according to method 1, the order of indicated TCI states may be distinguished on a DCI code point.

[0332] FIG. 15B illustrates a method for indicating an order between TCI states according to Method 2 according to an embodiment of the present disclosure.

[0333] 15B , according to method 2, the order of indicated TCI states may be distinguished on the MAC-CE.

[0334] In the case of method 1, the number of DCI code points may be greater than the number of TCI state sets activated using MAC-CE, and in the case of method 2, the number of TCI state sets activated using MAC-CE may be the same as the number of DCI code points.

[0335] Third embodiment: New antenna port indication method 3

[0336] The third embodiment proposes a method of performing new antenna port indication by designing new code points so as to eliminate the problem described in the first embodiment based on a series of rules.

[0337] The terminal may recognize whether to perform NC-JT by a method different from DMRS port indication, for example, by one or a combination of the methods listed below.

[0338] ● Number of indicated TCI states: If the number of TCI states configured as DCI code points is two or more, NC-JT is performed, and if the number of TCI states configured as DCI code points is one, single-TRP transmission is performed.

[0339] ● RNTI value: Cases for distinguishing the RNTI for NC-JT and the RNTI for single-TRP transmission.

[0340] If the terminal determines that the current transmission is NC-JT according to the above method, the table listed below can be used as the table indicating the antenna ports on the DCI. The table listed below can be designed by one or a combination of the rules to be proposed below.

[0341] Rule A) The proposed Rule A is a method that always uses fixed CDM groups 0 and 1 regardless of the type of DMRS, and the corresponding CDM groups are mapped to different TRPs.

[0342] Rule A-1) In Table 17-1 <DMRS type 1, maxlength = 1>, a total of two to four DMRS ports are allocated, and at least one DMRS port is allocated to each CDM group. The allocated DMRS ports range from 0 to 3. If a total of two DMRS ports are used, the corresponding DMRS ports become DMRS ports with the same frequency-domain cyclic shift or frequency-domain OCC in different CDM groups. For example, the two DMRS ports can be ports 0 and 2 with the same frequency-domain OCC w_f = [1, 1] in CDM groups 0 and 1 respectively, and can be ports 1 and 3 using w_f = [1, -1]. On the other hand, since DMRS ports 0 and 3 have different frequency-domain OCCs w_f = [1, 1] and w_f' = [1, -1] in CDM groups 0 and 1, the corresponding ports cannot be combined. If a total of three DMRS ports are used, the case of using two DMRS ports in CDM group 0 and one DMRS port in CDM group 1 (code point 2) and the opposite case (code point 3) will be considered. If four DMRS ports are used, two DMRS ports are used in both CDM group 0 and CDM group 1.

[0343]

Table 17-1

[0344]

[0345]

[0346] Rule A-2) In Table 17-2 <DMRS type 1, maxlength = 2, one codeword>, a total of 2 to 4 DMRS ports are allocated, and at least one DMRS port is allocated to each CDM group. Depending on the number of preamble symbols, in the case of one preamble symbol, the allocation is performed on DMRS ports 0 to 3, and in the case of two preamble symbols, the allocation is performed on DMRS ports 0 to 7. If a total of two DMRS ports are used (as in Rule A-1), the frequency-domain OCC in the corresponding CDM group must be the same. At the same time, the time-domain OCC of the corresponding CDM group can be the same or different. For example, DMRS port 0 and DMRS port 2 with the same time-domain OCC can be used in CDM groups {0, 1} respectively, and DMRS port 0 and DMRS port 6 with different time-domain OCC can also be used in CDM groups {0, 1}. Rule A-1 is applied to the case where three or more DMRS ports are used in total. In this case, the time-domain OCC applied to the corresponding CDM group {0, 1} can be the same or different.

[0347] ● Rule A-3) In Table 17-2 <DMRS type 1, maxlength = 2, two codewords>, a total of 5 to 8 DMRS ports are allocated, and the DMRS ports to be used are limited to the union of the DMRS ports corresponding to two or more code points in Table <xx-a2, DMRS type 1, maxlength = 2, one codeword>. For example, since DMRS ports {0, 3, 4, 5, 6} are not the union of the DMRS ports corresponding to the code points in Table <xx-a2, DMRS type 1, maxlength = 2, one codeword>, the corresponding ports cannot be used.

[0348]

Table 17-2

[0349]

[0350]

[0351]

[0352] ● Rule A-4) In Table 17-3 <DMRS type 2, maxlength = 1>, when using one codeword, a total of two to four DMRS ports are allocated, and at least one DMRS port is allocated to CDM groups 0 and 1. In addition, the frequency-domain OCC condition mentioned in Rule A-1 is applied here. If two codewords are used, the DMRS port union condition mentioned in Rule A-3 is applied here.

[0353]

Table 17-3

[0354]

[0355]

[0356] ● Rule A-5): In Table 17-4 <DMRS type 2, maxlength = 2>, a total of 2 to 4 DMRS ports are allocated, and at least one DMRS port is allocated to CDM groups 0 and 1. If one codeword is used, the frequency-domain OCC condition mentioned in Rule A-1 and the time-domain OCC condition mentioned in Rule A-2 are applied. If two codewords are used, the DMRS port union condition mentioned in Rule A-3 is applied.

[0357]

Table 17-4

[0358]

[0359]

[0360]

[0361] Rule B): The proposed Rule B is a method that always uses two CDM groups, uses CDM groups 0 and 1 in the case of DMRS type 1, and dynamically selects and uses two CDM groups from CDM groups 0, 1, and 2 in the case of DMRS type 2. In this case, the corresponding selected CDM groups can be mapped to different TRPs.

[0362] ● The above Rule A-1) is applied to Table 18-1 <DMRS type 1, maxlength = 1>.

[0363]

Table 18-1

[0364]

[0365]

[0366] ● In the case of one codeword, Rule A-2) is applied to Table 18-2 <DMRS Type 1, maxlength = 2>, and in the case of two codewords, Rule A-3) is applied to Table 18-2 <DMRS Type 1, maxlength = 2>.

[0367]

Table 18-2

[0368]

[0369]

[0370] ● Rule B-1) In Table 18-3 <DMRS Type 2, maxlength = 1, one codeword>, if the number of DMRS CDM groups without data is 2, the CDM group set {0, 1} is used, and if the number of DMRS CDM groups without data is 3, one of the CDM group sets {0, 1}, {0, 2}, and {1, 2} is selected and used. After selecting the CDM group set, Rule A-4) is applied. Rule A-4) is applied to Table 18-3 <DMRS Type 2, maxlength = 1, two codewords>.

[0371]

Table 18-3

[0372]

[0373] ● Rule B-2) In Table 18-4 <DMRS Type 2, maxlength = 2, one codeword>, as in Rule B-1) above, a CDM group set is selected. After selecting the CDM group set, the corresponding CDM group is restricted to using only the same time-domain OCC to prevent an increase in the DCI payload required to support different time-domain OCCs for the corresponding CDM group. Otherwise, Rule A-5) is applied. The above Rule A-5 is applied to Table 18-4 <DMRS Type 2, maxlength = 2, two codewords>.

[0374]

Table 18-4

[0375]

[0376]

[0377]

[0378]

[0379] Some DCI code points in Rule A or Rule B can be used to support multi-user MIMO transmission between NC-JT terminals or multi-user MIMO transmission between NC-JT terminals and single TRP terminals. For example, code points 0 and 1 in Table 18-1 can be indicated to different terminals A and B, respectively, and the base station can provide services to terminals A and B through the NC-JT multi-user MIMO transmission method. Alternatively, code point 5 in Table 18-3 can be indicated to terminal C that receives data through the NC-JT method, and code point 15 in Table 15-3-1 can be indicated to terminal D that receives data through the single TRP method, and the base station can provide services to terminals C and D through the multi-user MIMO transmission method. Among the DCI code points according to Rule A or Rule B, the code points that support multi-user MIMO transmission between NC-JT terminals can be all code points where one or more CDM groups overlap with each other. At the same time, among the code points, the code points that support multi-user MIMO transmission between NC-JT terminals and single TRP terminals can be all code points where the value of the field "CDM group without data" is greater than the number of CDM groups actually used.

[0380] At the same time, because the traffic load is relatively low, NC-JT can be used when multiple TRPs serve a single UE, and because the traffic load is relatively high, multi-user MIMO can be used when a single TRP serves multiple UEs. Therefore, when using NC-JT, multi-user MIMO transmission between NC-JT terminals or between NC-JT terminals and single TRP terminals can be ignored, and in this case, the DCI code points for multi-user MIMO transmission can be omitted.

[0381] According to an embodiment, only some of the DCI code points may be omitted. That is, i) only the DCI code points for multi-user MIMO between NC-JT terminals may be omitted, ii) only the DCI code points for multi-user MIMO between NC-JT terminals and single TRP terminals may be omitted, or iii) all DCI code points for multi-user MIMO may be omitted. One of the methods for case i) is to omit all code points having one or more CDM groups overlapping with each other and having the same total number of DMRS ports except one of them. One of the methods for case ii) is to omit all code points where the value of the field "CDM group with no data" is greater than the number of CDM groups actually used.

[0382] Fourth embodiment: Method for selecting one of the antenna port indication of the related art and the new antenna port indication

[0383] The fourth embodiment provides a method for a terminal to determine whether to use the antenna port indication of the related art or the new antenna port indication according to the situation.

[0384] The new antenna port indication according to some of the embodiments is to convert some or all of the contents indicated by the antenna port indication code points of the related art (i.e., the number of DMRS CDM groups without data or the DMRS port number) into new contents in order to efficiently support NC-JT. If the new antenna port indication is used, some or all of the functions of the antenna port indication of the related art will not be used. This means that compared with the existing transmission, the degree of freedom of multi-user MIMO transmission or single-user MIMO transmission may deteriorate at a specific time to support NC-JT, so it is necessary to modify the antenna port indication method according to the situation and apply the modified antenna port indication.

[0385] Specifically, the base station and the terminal may agree with each other so that when a specific PDCCH allocates NC-JT PDSCH (i.e., when a single PDCCH allocates two or more PDSCHs to the same service cell and the same bandwidth portion at the same time), the antenna port indication method is determined according to the values ​​of some fields in the DCI included in the corresponding PDCCH. The agreement between the base station and the terminal may be performed on the terminal that reports to the base station that NC-JT reception based on a single PDCCH is possible.

[0386] Fig.10 is a diagram illustrating a method of determining an antenna port indication according to an embodiment of the present disclosure.

[0387] refer to Fig.10 , the terminal attempts to detect the PDCCH (10-00) and determines whether there are two or more TCI states associated with the TCI code point indicated by the detected DCI (10-05).

[0388] If there is only one TCI state associated with the indicated TCI code point, the terminal assumes that the antenna port indication of the related art is used (10-10).

[0389] On the other hand, if there are two (or two or more) TCI states associated with the indicated TCI code point, the terminal assumes that a new antenna port indication is used (10-15).

[0390] This can be understood as, if a TCI code point related to a single TCI state is indicated, the terminal does not expect to use the new antenna port indication, or expects to use only the code point in the new antenna port indication that indicates the same content as the antenna port indication of the related art. Accordingly, even in the case of using NC-JT DCI that is distinguished by RNTI allocation, DCI format, payload of a specific field in DCI, its content, etc. (for example, NC-JT DCI can indicate TCI code points related to two or more TCI states at a time), all functions of the antenna port indication of the related art can be used.

[0391] As another example, the base station and the terminal may agree with each other to determine the antenna port indication method according to a higher layer signaling configuration value such as RRC or MAC CE. The protocol between the base station and the terminal may be performed on the terminal reporting to the base station that single PDCCH-based NC-JT reception is possible.

[0392] Fig.11 is a diagram illustrating a method of determining an antenna port indication according to an embodiment of the present disclosure.

[0393] refer to Fig.11 , the terminal attempts to detect the PDCCH (11-00) and determines whether there is a situation where two or more TCI states activated by the MAC CE are associated with one TCI code point (11-05).

[0394] If there is no case where two or more activated TCI states are associated with one TCI code point (ie, all TCI code points have only one associated TCI state), the terminal assumes that the antenna port indication of the related art is used (11-10).

[0395] On the other hand, if there is a situation where two or more activated TCI states are associated with one TCI code point (i.e., a situation where at least one TCI code point has two or more associated TCI states), the terminal assumes that a new antenna port indication is used (11-15). Therefore, even if a new antenna port indication is indicated by RRC configuration, the terminal can use all functions of the antenna port indication of the related art based on MAC CE signaling, thereby performing more flexible scheduling.

[0396] As another example, the base station and the terminal may agree with each other to determine the antenna port indication method according to the use case of NC-JT DCI distinguished by RNTI allocation, DCI format, payload of a specific field in DCI, its content, etc. (for example, NC-JT DCI is able to indicate TCI code points associated with two or more TCI states at one time). The agreement between the base station and the terminal may be performed on the terminal that reports to the base station that single PDCCH-based NC-JT reception is possible.

[0397] Fig.12 is a diagram illustrating a method of determining an antenna port indication according to an embodiment of the present disclosure.

[0398] refer to Fig.12 , the terminal attempts to detect the PDCCH (12-00) and determines whether the detected PDCCH includes the DCI for NC-JT (12-05).

[0399] If the detected DCI is not intended for single PDCCH based NC-JT, the terminal assumes that the antenna port indication of the related art is used (12-10).

[0400] On the other hand, if the detected DCI is intended for single PDCCH-based NC-JT, the terminal assumes that a new antenna port indication is used (12-15). Therefore, the terminal can dynamically select an antenna port indication method depending on the type of DCI, thereby performing more flexible scheduling.

[0401] Fig.13 is a block diagram showing a structure of a terminal in a wireless communication system according to an embodiment of the present disclosure.

[0402] refer to Fig.13 , the terminal can be configured to include transceivers 13-00 and 13-10, and a processing unit 13-05 including a memory and a processor. The transceivers 13-00 and 13-10 of the terminal and the processing unit 13-05 can operate according to the communication method of the terminal as described above. However, the elements of the terminal are not limited to the above examples. For example, the terminal may include more or less elements than the aforementioned elements. In addition, the transceivers 13-00 and 13-10 and the processing unit 13-05 can be implemented in a single chip.

[0403] The transceivers 13-00 and 13-10 can send signals to and receive signals from the base station. The signals may include control information and data. To this end, the transceivers 13-00 and 13-10 may be configured to include an RF transmitter for up-converting and amplifying the frequency of the transmitted signal, and an RF receiver for low-noise amplifying the received signal and down-converting its frequency. However, this is only an example of the transceivers 13-00 and 13-10, and the elements of the transceivers 13-00 and 13-10 are not limited to the RF transmitter and the RF receiver.

[0404] Furthermore, the transceivers 13-00 and 13-10 may receive a signal through a wireless channel, may output a signal to the processing unit 13-05, and may transmit a signal output from the processing unit 13-05 through a wireless channel.

[0405] The processing unit 13-05 may store programs and data required for the terminal operation. In addition, the processing unit 13-05 may store control information or data included in the signal obtained from the terminal. The processing unit 13-05 may include a memory configured as a storage medium, such as ROM, RAM, hard disk, CD-ROM and DVD or a combination thereof.

[0406] In addition, the processing unit 13-05 can control a series of processes so that the terminal can operate according to the above embodiments. According to some embodiments, the processing unit 13-05 can determine whether to apply a new antenna port indication method, and can control the elements of the terminal to apply the new antenna port indication according to it.

[0407] Fig.14 is a block diagram showing a structure of a base station in a wireless communication system according to an embodiment of the present disclosure.

[0408] refer to Fig.14 , the base station can be configured to include transceivers 14-00 and 14-10, and a processing unit 14-05 including a memory and a processor. The transceivers 14-00 and 14-10 of the base station and the processing unit 14-05 can operate according to the communication method of the base station as described above. However, the elements of the base station are not limited to the above examples. For example, the base station may include more or fewer elements than the aforementioned elements. In addition, the transceivers 14-00 and 14-10 and the processing unit 14-05 can be implemented in a single chip.

[0409] Transceivers 14-00 and 14-10 can send signals to and receive signals from terminals. The signals may include control information and data. To this end, transceivers 14-00 and 14-10 may be configured to include an RF transmitter for up-converting and amplifying the frequency of the transmitted signal, and an RF receiver for low-noise amplifying the received signal and down-converting its frequency. However, this is only an example of transceivers 14-00 and 14-10, and the elements of transceivers 14-00 and 14-10 are not limited to RF transmitters and RF receivers.

[0410] Furthermore, the transceivers 14-00 and 14-10 may receive a signal through a wireless channel, may output a signal to the processing unit 14-05, and may transmit a signal output from the processing unit 14-05 through a wireless channel.

[0411] The processing unit 14-05 may store programs and data required for the base station operation. In addition, the processing unit 14-05 may store control information or data included in the signal obtained from the base station. The processing unit 14-05 may include a memory configured as a storage medium, such as a ROM, RAM, hard disk, CD-ROM and DVD or a combination thereof.

[0412] In addition, the processing unit 14-05 can control a series of processes so that the base station can operate according to the above embodiments. According to some embodiments, the processing unit 14-05 can determine whether to apply a new antenna port indication method, and can control various elements of the base station to apply the new antenna port indication according to it.

[0413] The methods disclosed in the claims and / or the methods according to the various embodiments described in the present disclosure may be implemented by hardware, software, or a combination of hardware and software.

[0414] When these methods are implemented by software, a computer-readable storage medium for storing one or more programs (software modules) may be provided. One or more programs stored in the computer-readable storage medium may be configured to be executed by one or more processors in an electronic device. At least one program may include instructions for causing an electronic device to perform methods according to various embodiments of the present disclosure as defined by the appended claims and / or disclosed herein.

[0415] Programs (software modules or software) can be stored in non-volatile memory, including random access memory and flash memory, read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), magnetic disk storage devices, compact disk ROM (CD-ROM), digital versatile disk (DVD) or other types of optical storage devices or tapes. Alternatively, any combination of some or all of them can form a memory storing the program. In addition, a plurality of such memories can be included in the electronic device.

[0416] In addition, the program can be stored in an attachable storage device that can access the electronic device through a communication network such as the Internet, an intranet, a local area network (LAN), a wide area network (WLAN), and a storage area network (SAN) or a combination thereof. Such a storage device can access the electronic device via an external port. In addition, a separate storage device on a communication network can access a portable electronic device.

[0417] 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 to the presented situation, and the present disclosure is not limited to the elements expressed in the singular or plural form. 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.

[0418] 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.

[0419] 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 essential spirit and scope of the present disclosure.

[0420] Furthermore, in the method of the present disclosure, some or all of the contents of each embodiment may be combined without departing from the essential spirit and scope of the present disclosure.

[0421] While the invention has been shown and described with reference to various embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made without departing from the spirit and scope of the invention as defined by the appended claims and their equivalents.

Claims

1. A method performed by a terminal in a communication system, the method comprising: receiving, from a base station, configuration information associated with a demodulation reference signal (DMRS) for receiving data; receiving control information including an antenna port field and a transmission configuration indication (TCI) field from a base station; Identifying a DMRS port assigned to the terminal, wherein the DMRS port is identified based on configuration information, an antenna port field, and whether at least one code point associated with a TCI field corresponds to a plurality of TCI states; as well as Data is received from the base station based on the identified DMRS port.

2. The method according to claim 1, wherein: In a case where all code points associated with the TCI field correspond to at most one TCI state, a DMRS port allocated to the terminal is identified based on the first antenna port indication table.

3. The method according to claim 1, wherein: In a case where at least one code point associated with the TCI field corresponds to a plurality of TCI states, a DMRS port allocated to the terminal is identified based on the second antenna port indication table.

4. The method according to claim 3, wherein: Each of the information associated with the second antenna port indication table includes entries corresponding to DMRS port indexes 1000 , 1002 , and 1003 .

5. The method according to claim 1, wherein: In the case where the code point indicated by the TCI field corresponds to a plurality of TCI states and the identified DMRS port corresponds to a plurality of code division multiplexing (CDM) groups, each of the plurality of TCI states corresponds to a different CDM group.

6. A method performed by a base station in a communication system, the method comprising: Sending configuration information associated with a demodulation reference signal (DMRS) for sending data to a terminal; Sending control information including an antenna port field and a transmission configuration indication (TCI) field to the terminal; Identifying a DMRS port assigned to the terminal, wherein the DMRS port is identified based on configuration information, an antenna port field, and whether at least one code point associated with a TCI field corresponds to a plurality of TCI states; as well as Data is sent to the terminal based on the identified DMRS port.

7. The method according to claim 6, wherein: In a case where all code points associated with the TCI field correspond to at most one TCI state, a DMRS port allocated to the terminal is identified based on the first antenna port indication table.

8. The method according to claim 6, wherein: In a case where at least one code point associated with the TCI field corresponds to a plurality of TCI states, a DMRS port allocated to the terminal is identified based on the second antenna port indication table.

9. The method according to claim 8, wherein: Each of the information associated with the second antenna port indication table includes entries corresponding to DMRS port indexes 1000 , 1002 , and 1003 .

10. The method according to claim 6, wherein: In the case where the code point indicated by the TCI field corresponds to a plurality of TCI states and the identified DMRS port corresponds to a plurality of code division multiplexing (CDM) groups, each of the plurality of TCI states corresponds to a different CDM group.

11. A terminal in a communication system, the terminal comprising: Transceiver; as well as The processor is configured as: receiving, via a transceiver, configuration information associated with a demodulation reference signal (DMRS) for receiving data from a base station; receiving, via the transceiver, control information including an antenna port field and a transmission configuration indication (TCI) field from a base station; Identifying a DMRS port assigned to the terminal, wherein the DMRS port is identified based on configuration information, an antenna port field, and whether at least one code point associated with a TCI field corresponds to a plurality of TCI states; as well as Data is received from the base station via the transceiver based on the identified DMRS port.

12. The terminal according to claim 11, wherein: In a case where all code points associated with the TCI field correspond to at most one TCI state, a DMRS port allocated to the terminal is identified based on the first antenna port indication table.

13. The terminal according to claim 11, wherein: In a case where at least one code point associated with the TCI field corresponds to a plurality of TCI states, a DMRS port allocated to the terminal is identified based on the second antenna port indication table.

14. A base station in a communication system, the base station comprising: Transceiver; as well as The processor is configured as: sending, via the transceiver, to the terminal, configuration information associated with a demodulation reference signal (DMRS) for transmitting data; Sending control information including an antenna port field and a transmission configuration indication (TCI) field to a terminal via a transceiver; Identifying a DMRS port assigned to the terminal, wherein the DMRS port is identified based on configuration information, an antenna port field, and whether at least one code point associated with a TCI field corresponds to a plurality of TCI states; as well as Data is sent to the terminal based on the identified DMRS port.

15. The base station according to claim 14, wherein: In a case where all code points associated with the TCI field correspond to at most one TCI state, identifying a DMRS port allocated to the terminal based on the first antenna port indication table, and In a case where at least one code point associated with the TCI field corresponds to a plurality of TCI states, a DMRS port allocated to the terminal is identified based on the second antenna port indication table.

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