Method and apparatus for repeatedly transmitting / receiving downlink control information in a wireless communication system

Abstract

Disclosed is a method and device for repeatedly transmitting / receiving downlink control information in a wireless communication system, the method performed by a user equipment (UE) in the wireless communication system including transmitting, to a base station, first information related to physical downlink control channel (PDCCH) repetition transmission, the first information including second information related to a number of blind decoding times of a PDCCH candidate, receiving, from the base station, configuration information about a control resource set and a search space configured for PDCCH transmission, and receiving, from the base station, control information about a first PDCCH and a second PDCCH based on the first information and the configuration information, the second PDCCH being a repetition of the first PDCCH.

Description

[0001] This application is a divisional application of the invention patent application filed on October 22, 2021, with application number 202180072405.4 and entitled "Method and apparatus for repeatedly transmitting / receiving downlink control information in a wireless communication system". Technical Field

[0002] This disclosure relates to methods and apparatus for transmitting or receiving downlink control information in a wireless communication system. Background Technology

[0003] To meet the increased demand for wireless data services since the deployment of 4G communication systems, efforts have been made to develop improved 5G or pre-5G communication systems. Therefore, 5G or pre-5G communication systems are also referred to as "beyond 4G networks" or "post-LTE" systems. 5G communication systems are considered to be implemented in higher frequency (millimeter wave) bands (e.g., the 60GHz band) to achieve higher data rates. To reduce radio wave propagation loss and increase transmission distance, beamforming, massive MIMO, full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and massive MIMO technologies have been discussed in 5G communication systems. Furthermore, in 5G communication systems, system network improvements are being developed based on advanced small cells, cloud radio access networks (RAN), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, mobile networks, cooperative communication, cooperative multipoint (CoMP), and receiver interference cancellation. In 5G systems, hybrid FSK and QAM modulation (FQAM) and sliding window superposition coding (SWSC) have also been developed as advanced coding modulation (ACM), as well as filter bank multicarrier (FBMC), non-orthogonal multiple access (NOMA) and sparse code multiple access (SCMA) as advanced access technologies.

[0004] The internet, a human-centric network of connections where humans 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), combining IoT technology with big data processing, has emerged through connectivity to cloud servers. As essential technological elements for realizing IoT, such as sensing technology, wired / wireless communication and network infrastructure, service interface technology, and security technology, sensor networks, machine-to-machine (M2M) communication, and machine-type communication (MTC) have recently been studied. Such an IoT environment can provide intelligent internet technology services, creating new value for human life by collecting and analyzing data generated between interconnected objects. Through the convergence and integration of existing information technology (IT) and various industrial applications, IoT can be applied to a wide range of fields, including smart homes, smart buildings, smart cities, smart or connected cars, smart grids, healthcare, smart appliances, and advanced medical services.

[0005] Correspondingly, various attempts have been made to apply 5G communication systems to Internet of Things (IoT) networks. For example, technologies such as sensor networks, machine-type communication (MTC), and machine-to-machine (M2M) communication can be implemented using beamforming, MIMO, and array antennas. Cloud radio access networks (RAN), as an application of the aforementioned big data processing technologies, can also be considered an example of the integration of 5G and IoT technologies.

[0006] With the development of wireless communication systems as described above, various services can be provided, thus requiring solutions for effectively providing these services. Summary of the Invention

[0007] Technical issues

[0008] The disclosed embodiments will provide an apparatus and method capable of efficiently providing services in a wireless communication system.

[0009] The disclosed embodiments will provide an apparatus and method for efficiently transmitting or receiving downlink control information in a wireless communication system.

[0010] The disclosed embodiments will provide an apparatus and method for efficiently repeating the transmission or reception of downlink control information in a wireless communication system.

[0011] Technical solution

[0012] According to embodiments of this disclosure, a method performed by a user equipment (UE) in a wireless communication system is provided, the method comprising: sending to a base station first information relating to repeated transmission of a physical downlink control channel (PDCCH), the first information including second information relating to the number of blind decoding attempts of a PDCCH candidate; receiving from the base station configuration information regarding a control resource set and a search space configured for PDCCH transmission; and receiving from the base station control information regarding a first PDCCH and a second PDCCH, the second PDCCH being a repeat of the first PDCCH, based on the first information and the configuration information.

[0013] Furthermore, according to embodiments of this disclosure, a UE in a wireless communication system is provided. The UE includes a transceiver and a processor. The processor is configured to send first information related to PDCCH repetition transmission to a base station via the transceiver. The first information includes second information associated with the number of blind decoding attempts for PDCCH candidates. The processor receives configuration information from the base station via the transceiver regarding a control resource set and search space configured for PDCCH transmission. Based on the first information and the configuration information, the processor receives control information from the base station via the transceiver regarding a first PDCCH and a second PDCCH, wherein the second PDCCH is a repetition of the first PDCCH.

[0014] Furthermore, according to embodiments of this disclosure, a method performed by a base station in a wireless communication system is provided, the method comprising: receiving from a UE first information related to PDCCH retransmission, the first information including second information associated with the number of blind decoding attempts of PDCCH candidates; sending to the UE configuration information regarding a control resource set and search space configured for PDCCH transmission; and, based on the information and configuration information, sending to the UE control information regarding a first PDCCH and a second PDCCH, the second PDCCH being a repetition of the first PDCCH.

[0015] Furthermore, according to embodiments of this disclosure, a base station in a wireless communication system is provided. The base station includes a transceiver and a processor. The processor is configured to receive, via the transceiver, first information related to repeated PDCCH transmissions from a UE, the first information including second information associated with the number of blind decoding attempts for PDCCH candidates; to send via the transceiver first information to the UE configuration information regarding a control resource set and search space configured for PDCCH transmission; and, based on the first information and the configuration information, to send via the transceiver control information regarding a first PDCCH and a second PDCCH to the UE.

[0016] Furthermore, according to embodiments of this disclosure, the number of blind decoding attempts for a PDCCH candidate corresponds to the number of PDCCH candidate groups.

[0017] Furthermore, according to an embodiment of this disclosure, the second information indicates that the number of blind decoding attempts for the PDCCH candidate is counted as 2.

[0018] Furthermore, according to an embodiment of this disclosure, the second information indicates that the number of blind decoding attempts for the PDCCH candidate is counted as 3.

[0019] Furthermore, according to embodiments of this disclosure, control information is repeatedly received through different sets of control resources or different sets of search spaces within a single set of control resources.

[0020] According to embodiments of this disclosure, a method performed by a user equipment (UE) in a wireless communication system is provided, the method comprising: sending to a base station first information related to repetition of a physical downlink control channel (PDCCH), the first information including second information indicating a UE capability to count two PDCCH candidates as three PDCCH candidates; receiving from the base station third information for controlling a resource set and fourth information for searching a space; and listening to PDCCH candidates based on the second, third, and fourth information.

[0021] Furthermore, according to embodiments of this disclosure, a user equipment (UE) in a wireless communication system is provided. The UE includes: a transceiver; and a processor configured to: transmit, via the transceiver, to a base station, first information related to repetition of the physical downlink control channel (PDCCH), the first information including second information indicating the UE's ability to count two PDCCH candidates as three PDCCH candidates; receive, via the transceiver, third information for controlling resource sets and fourth information for searching the space from the base station; and listen to PDCCH candidates based on the second, third, and fourth information.

[0022] Furthermore, according to embodiments of this disclosure, a method performed by a base station in a wireless communication system is provided, the method comprising: receiving from a user equipment (UE) first information related to repetition of a physical downlink control channel (PDCCH), the first information including second information indicating a UE capability to count two PDCCH candidates as three PDCCH candidates; transmitting third information for controlling a resource set and fourth information for searching a space; and transmitting downlink control information about the PDCCH candidates based on the second, third, and fourth information.

[0023] Furthermore, according to embodiments of this disclosure, a base station in a wireless communication system is provided. The base station includes: a transceiver; and a processor configured to: receive, via the transceiver, first information related to physical downlink control channel (PDCCH) repetition from a user equipment (UE), the first information including second information indicating the UE's ability to count two PDCCH candidates as three PDCCH candidates; transmit third information for controlling resource sets and fourth information for searching the space; and transmit downlink control information about PDCCH candidates to the UE via the transceiver based on the second, third, and fourth information.

[0024] Before proceeding with the detailed description below, it may be advantageous to define certain words and phrases used throughout this patent document: the terms “comprising” and “including” and their derivatives mean unrestricted inclusion; the term “or” is inclusive, meaning and / or; the phrases “associated with” and “associated with” and their derivatives may mean including, being included, interconnected with, containing, being contained, connected to or connected to, coupled to or coupled to, communicable with, cooperating, interleaving, juxtaposing, proximate, bound to or bound to, having, having characteristics, etc.; the term “controller” means any device, system, or part thereof that controls at least one operation, such device may be implemented in hardware, firmware, or software, or at least some combination of both. It should be noted that the functionality associated with any particular controller may be centralized or distributed, local or remote.

[0025] Furthermore, the various functions described below can be implemented or supported by one or more computer programs, each computer program being formed by computer-readable program code and contained in a computer-readable medium. The terms "application" and "program" refer to one or more computer programs, software components, instruction sets, procedures, functions, objects, classes, instances, associated data, or portions thereof suitable for implementation in appropriate computer-readable program code. The phrase "computer-readable program code" includes any type of computer code, including source code, object code, and executable code. The phrase "computer-readable medium" includes any type of medium accessible by a computer, such as read-only memory (ROM), random access memory (RAM), hard disk drive, optical disc (CD), digital video disc (DVD), or any other type of storage. "Non-transitory" computer-readable media does not include wired, wireless, optical, or other communication links that transmit transient electrical or other signals. Non-transitory computer-readable media includes media that can permanently store data and media that can store data and be rewritten later, such as rewritable optical discs or erasable storage devices.

[0026] This patent document provides definitions for certain words and phrases, and those skilled in the art should understand that, in many cases, if not most, such definitions apply to the prior and future use of the words and phrases defined in this way. Attached Figure Description

[0027] To gain a more complete understanding of this disclosure and its advantages, reference is now made to the following description in conjunction with the accompanying drawings, wherein like reference numerals denote like parts:

[0028] Figure 1 This is a diagram illustrating the basic structure of the time-frequency domain in a wireless communication system according to an embodiment of the present disclosure;

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

[0030] Figure 3 This is a diagram illustrating an example of bandwidth configuration in a wireless communication system according to an embodiment of the present disclosure;

[0031] Figure 4 This is a diagram illustrating an example of the configuration of the control resource set of a downlink control channel in a wireless communication system according to an embodiment of the present disclosure;

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

[0033] Figure 5B This is a diagram illustrating a situation in a wireless communication system where a UE can have multiple PDCCH listening locations within a time slot via a span, according to an embodiment of the present disclosure.

[0034] Figure 6 This is a diagram illustrating an example of DRX operation in a wireless communication system according to an embodiment of the present disclosure;

[0035] Figure 7 This is a diagram illustrating an example of base station beam assignment configured according to TCI state in a wireless communication system according to an embodiment of the present disclosure;

[0036] Figure 8 This is a diagram illustrating an example of a TCI state assignment method for a PDCCH in a wireless communication system according to an embodiment of the present disclosure;

[0037] Figure 9 This is a diagram illustrating the TCI indication MACCE signaling structure for PDCCH DMRS in a wireless communication system according to an embodiment of the present disclosure;

[0038] Figure 10This is a diagram illustrating an example of the CORESET and search space beam configuration in a wireless communication system according to an embodiment of the present disclosure;

[0039] Figure 11 This is a diagram illustrating an example of frequency axis resource allocation for a PDSCH in a wireless communication system according to an embodiment of the present disclosure;

[0040] Figure 12 This is a diagram illustrating an example of time axis resource allocation for a PDSCH in a wireless communication system according to an embodiment of the present disclosure;

[0041] Figure 13 This is a diagram illustrating an example of time-axis resource allocation based on the subcarrier spacing of the data channel and the control channel in a wireless communication system according to an embodiment of the present disclosure;

[0042] Figure 14 This is a diagram illustrating the wireless protocol structure of the UE and the base station in a wireless communication system according to embodiments of the present disclosure, under single-cell, carrier aggregation, and dual-connectivity scenarios.

[0043] Figure 15 This is a diagram illustrating an example of antenna port configuration and resource allocation for cooperative communication in a wireless communication system according to an embodiment of the present disclosure;

[0044] Figure 16 This is a diagram illustrating an example of downlink control information (DCI) configuration for cooperative communication in a wireless communication system according to an embodiment of the present disclosure;

[0045] Figure 17 This is a diagram illustrating the operation of the UE, which is used to count the number of PDCCH candidate groups and CCEs during PDCCH retransmission based on whether the base station's transmission conditions are met and the UE's capability report.

[0046] Figure 18 This is a diagram illustrating the operation of a UE according to various embodiments of the present disclosure, which is used to count the number of PDCCH candidate groups and CCEs during PDCCH retransmission based on whether the base station's transmission conditions are met and the UE capability report;

[0047] Figure 19 This is a diagram illustrating the structure of a UE in a wireless communication system according to an embodiment of the present disclosure; and

[0048] Figure 20 This is a diagram illustrating the structure of a base station in a wireless communication system according to an embodiment of the present disclosure. Detailed Implementation

[0049] The following discussion Figures 1 to 20The various embodiments used to describe the principles of this disclosure in this patent document are merely exemplary and should not be construed in any way as limiting the scope of this disclosure. Those skilled in the art will understand that the principles of this disclosure can be implemented in any suitably arranged system or apparatus.

[0050] In the following, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0051] In describing embodiments of this disclosure, descriptions related to or not directly related to techniques known in the art will be omitted. Unnecessary descriptions are omitted to prevent obscuring the main ideas of this disclosure and to more clearly convey them.

[0052] For the same reason, some elements may be exaggerated, omitted, or shown schematically in the accompanying drawings. Furthermore, the size of each element does not perfectly reflect its actual size. In the accompanying drawings, identical or corresponding elements have the same reference numerals.

[0053] The advantages and features of this disclosure, as well as the ways in which they are implemented, will become apparent from the embodiments described in detail below with reference to the accompanying drawings. However, this disclosure is not limited to the embodiments set forth below, but can be implemented in various different forms. The following embodiments are provided only to fully disclose this disclosure and to inform those skilled in the art of its scope, and this disclosure is limited only by the scope of the appended claims. Throughout the specification, the same or similar reference numerals denote the same or similar elements. Furthermore, in describing this disclosure, detailed descriptions of known functions or configurations incorporated herein will be omitted where it may unnecessarily obscure the subject matter of the disclosure. The terminology described below is defined in consideration of the functions in this disclosure and may vary depending on the user, the user's intention, or custom. Therefore, the definition of the terminology should be based on the entire contents of the specification.

[0054] In the following text, a base station is the entity that performs resource allocation to user equipment (UE) and can be at least one of a gNode B, gNB, eNode B, eNB, Node B, base station (BS), radio access unit, base station controller, or node on a network. A base station can be a network entity in an NR system, including at least one of an Integrated Access Backhaul Donor (IAB-donor) and an IAB node (IAB-node), where the IAB-donor is a gNB that provides network access to (multiple) UEs via backhaul and access links, and the IAB-node is a radio access network (RAN) node that supports (multiple) NR access links to (multiple) UEs and supports NR backhaul links to the IAB-donor or other IAB-nodes. UEs can wirelessly connect via IAB nodes and can send or receive data from an IAB-donor connected to at least one IAB-node via a backhaul link.

[0055] The UE may include a terminal, mobile station (MS), cellular phone, smartphone, computer, or multimedia system capable of performing communication functions. In this disclosure, "downlink" refers to the radio link through which a base station transmits signals to the UE, and "uplink" refers to the radio link through which the UE transmits signals to the base station. Furthermore, although the following description is by way of example directed to LTE or LTE-A systems, embodiments of this disclosure can also be applied to other communication systems with similar technical backgrounds or channel types. Examples of other communication systems may include fifth-generation mobile communication technologies (5G, New Radio, NR) developed in addition to LTE-A, and in the following description, "5G" may be a concept encompassing existing LTE, LTE-A, and other similar services. Moreover, based on the determination of those skilled in the art, this disclosure can be applied to other communication systems with some modifications without explicitly departing from the scope of this disclosure.

[0056] Here it will be understood that each box shown in the flowchart, and combinations of boxes shown in the flowchart, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, special-purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in one or more boxes of the flowchart. These computer program instructions can also be stored in a computer-usable or computer-readable storage medium, which can instruct the computer or other programmable data processing apparatus to operate in a particular manner, such that the instructions stored in the computer-usable or computer-readable storage medium produce an article of manufacture including instruction means for implementing the functions specified in one or more boxes of the flowchart. The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus, thereby producing a computer-implemented process, such that the instructions, which execute on the computer or other programmable apparatus, provide steps for implementing the functions specified in one or more boxes of the flowchart.

[0057] Furthermore, each box in the flowchart can represent a module, code segment, or portion of code, which includes one or more executable instructions for implementing the specified logical function(s). It should also be noted that in some alternative implementations, the functions mentioned in the boxes may not appear in a specific order. For example, two boxes shown consecutively may actually be executed substantially simultaneously, or these boxes may sometimes be executed in reverse order, depending on the functions involved.

[0058] As used herein, "cell" refers to a software or hardware element that performs a predetermined function, such as a field-programmable gate array (FPGA) or application-specific integrated circuit (ASIC). However, "cell" does not always have a meaning limited to software or hardware. A "cell" can be configured to be stored in addressable storage media or to execute one or more processors. Therefore, a "cell" includes, for example, software elements, object-oriented software elements, class elements or task elements, processes, functions, attributes, procedures, subroutines, program code segments, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and parameters. The elements and functions provided by a "cell" can be combined into a smaller number of elements or "cells," or divided into a larger number of elements or "cells." Furthermore, elements and "cells" can be implemented as replicas of one or more CPUs within a device or secure multimedia card. Additionally, a "cell" in the embodiments may include one or more processors.

[0059] Wireless communication systems have evolved from initial wireless communication systems that provided voice-oriented services to broadband wireless communication systems that provide high-speed and high-quality packet data services, such as wireless communication systems based on communication standards including 3GPP High-Speed ​​Packet Access (HSPA), Long Term Evolution (LTE) (or Evolved Universal Terrestrial Radio Access (E-UTRA)), LTE-Advanced (LTE-A), LTE-Pro, 3GPP2 High-Speed ​​Packet Data (HRPD), Ultra Mobile Broadband (UMB), and IEEE 802.16e.

[0060] In LTE systems, a representative example of broadband wireless communication systems, the downlink (DL) uses an Orthogonal Frequency Division Multiplexing (OFDM) scheme, while the uplink (UL) uses a Single-Carrier Frequency Division Multiple Access (SC-FDMA) scheme. The uplink refers to the radio link through which the UE transmits data or control signals to the base station (BS) (or eNode B), and the downlink refers to the radio link through which the base station transmits data or control signals to the UE. In this multiple access scheme, data or control information for each user can typically be distinguished by assigning and manipulating time-frequency resources. Each user's data or control information will be transmitted on those time-frequency resources to avoid overlap, i.e., to establish orthogonality.

[0061] 5G communication systems, the future communication systems following LTE, should be able to freely reflect the various requirements of users, service providers, and others, and therefore should support services that simultaneously meet diverse needs. Services considered for 5G communication systems include enhanced mobile broadband (eMBB) communication, massive machine-type communication (mMTC), and ultra-reliable low-latency communication (URLLC).

[0062] eMBB aims to provide higher data transmission rates than those supported by existing LTE, LTE-A, or LTE-Pro systems. For example, in a 5G communication system, from a base station's perspective, eMBB should be able to provide a maximum data rate (peak data rate) of 20 Gbps in the downlink and a peak data rate of 10 Gbps in the uplink. 5G communication systems need to provide both peak data rates and increased perceived data rates for the UE. To meet these requirements, various transmit and receive technologies need improvement, including more advanced multi-antenna (Multiple-Input Multiple-Output (MIMO)) transmission technologies. While a maximum transmission bandwidth of 20 MHz can be used to transmit signals in the 2 GHz band used by LTE, in 5G communication systems, the required data transmission rates can be met by using a wider frequency bandwidth than 20 MHz in the 3 to 6 GHz band or in the 6 GHz or higher bands.

[0063] Meanwhile, mMTC is considering supporting application services such as the Internet of Things (IoT) in 5G communication systems. To effectively deliver IoT, mMTC may need to support large-scale UE access within a cell, enhanced UE coverage, improved battery life, and reduced UE cost. IoT attaches to multiple sensors and various devices to support communication functions, meaning it should be able to support a large number of UEs within a cell (e.g., 1,000,000 UEs / km²). Due to the nature of the service, UEs supporting mMTC may be located in shadow areas not covered by the cell, such as basements of buildings, thus requiring wider coverage compared to other services provided by 5G communication systems. UEs supporting mMTC may need to be low-cost UEs, and due to the difficulty in frequently replacing UE batteries, very long battery life, such as 10 to 15 years, may be required.

[0064] Finally, URLLC corresponds to cellular-based wireless communication services for specific purposes (mission-critical). Examples include services such as remote control of robots or machines, industrial automation, unmanned aerial vehicles, remote healthcare, and emergency alarms. Therefore, communication provided by URLLC should offer very low latency and very high reliability. For example, URLLC-enabled services should meet an air interface latency of less than 0.5 milliseconds and a packet error rate of 10⁻⁵ or lower. Therefore, for URLLC-enabled services, 5G systems may need to provide shorter Transmission Time Intervals (TTIs) than other services, and there may be design challenges in allocating wide resources in the frequency band to ensure the reliability of the communication link.

[0065] Three 5G services—eMBB, URLLC, and mMTC—can be reused and transmitted within a single system. Different transmission or reception technologies and parameters can be used across services to meet their varying requirements. 5G is not limited to these three services.

[0066] For the convenience of the following description, some terms and names defined in 3GPP standards (standards for 5G, NR, LTE, or similar systems) may be used. However, this disclosure is not limited to the terms and names and can be applied equivalently to systems conforming to other standards. For ease of description, terms used in the following description to identify access nodes, to indicate network entities, to indicate messages, to indicate interfaces between network entities, to indicate various identification information, etc., are shown. Therefore, this disclosure is not limited to the terms used herein, and other terms referring to objects with equivalent technical meanings may be used.

[0067] [NR Time and Frequency Resources]

[0068] The frame structure of the 5G system will be described in more detail below with reference to the accompanying drawings.

[0069] Figure 1 This is a diagram illustrating the basic structure of the time-frequency domain, which is the radio resource region for transmitting data or control channels in a 5G system.

[0070] exist Figure 1 In the diagram, the horizontal axis represents the time domain, and the vertical axis represents the frequency domain. The basic unit of resources in both the time and frequency domains is a resource element (RE) 101, which can be defined as one orthogonal frequency division multiplexing (OFDM) symbol 102 on the time axis and one subcarrier 103 on the frequency axis. In the frequency domain... (For example, 12 consecutive REs can form a resource block (RB) 104. In Figure 1 middle, This refers to the number of OFDM symbols per subframe of 110 for the subcarrier spacing configuration (μ), and a more detailed description of the resource structure in a 5G system can be obtained by referring to Section 4 of the TS38.211 standard.

[0071] Figure 2 This is a diagram illustrating the time slot structure considered in a 5G system.

[0072] Figure 2 An example of the structure of frame 200, subframe 201, and time slot 202 is shown. A frame 200 can be defined as 10 ms. A subframe 201 can be defined as 1 ms, so a frame 200 can include a total of 10 subframes 201. A time slot 202 or 203 can be defined as 14 OFDM symbols (i.e., the number of symbols per time slot (...)). ( ) = 14). A subframe 201 may include one or more time slots 202 and 203, and the number of time slots 202 and 203 in a subframe 201 may vary according to the configuration value μ 204 or 205 of the subcarrier spacing. Figure 2 In the examples, the cases of μ=0 204 and μ=1 205 are shown as subcarrier spacing configuration values. In the case of μ=0 204, one subframe 201 may include one time slot 202, while in the case of μ=1 205, one subframe 201 may include two time slots 203. That is, the number of time slots per subframe ( The number of time slots per frame can vary depending on the configuration value μ of the subcarrier spacing, and correspondingly, the number of time slots per frame ( () can change. and The corresponding subcarrier spacing configuration μ can be defined in Table 1 below.

[0073] [Table 1]

[0074]

[0075] [Bandwidth Component (BWP)]

[0076] Next, the bandwidth portion (BWP) configuration in a 5G communication system will be described in detail with reference to the accompanying drawings.

[0077] Figure 3 This is a diagram illustrating an example configuration of the bandwidth portion in a 5G communication system.

[0078] Figure 3 An example is shown where the UE bandwidth 300 is configured to have two bandwidth portions, namely bandwidth portion #1 301 and bandwidth portion #2 302. The base station can configure one or more bandwidth portions for the UE, and the following information can be configured for each bandwidth portion.

[0079] [Table 2]

[0080]

[0081] In [Table 2], “locationAndBandwidth” indicates the location and bandwidth in the frequency domain of the bandwidth section, “subcarrierSpacing” indicates the subcarrier spacing to be used in the bandwidth section, and “cyclicPrefix” indicates the extended cyclic prefix (CP) of the bandwidth section.

[0082] This disclosure is not limited to the examples described above. In addition to configuration information, various parameters related to bandwidth portions can be configured for the UE. The base station can transmit information to the UE via upper-layer signaling (e.g., Radio Resource Control (RRC) signaling). At least one of the configured bandwidth portions can be activated. Whether the configured bandwidth portion is activated can be transmitted from the base station to the UE in a semi-static manner via RRC signaling, or can be transmitted dynamically via downlink control information (DCI).

[0083] According to some embodiments, prior to RRC connection, the base station can configure an initial bandwidth portion (BWP) for initial access for the UE via the Master Information Block (MIB). More specifically, during the initial access phase, the UE can receive configuration information for the search space and control area (control resource set (CORESET)), wherein a PDCCH for receiving system information required for initial access (which may correspond to the Residual System Information (RMSI) or System Information Block 1 (SIB1)) can be transmitted via the MIB. Each of the search space and control resource set configured via the MIB can be considered as identity (ID) 0. The control resource set and search space configured via the MIB can be referred to as the common control resource set and common search space, respectively. The base station can notify the UE of configuration information, such as frequency allocation information, time allocation information, and the parameter set of control resource set #0, via the MIB. The base station can notify the UE of the configuration information for the listening period and timing of control resource set #0, i.e., the configuration information for search space #0, via the MIB. The UE can consider the frequency domain of control resource set #0, configured to be obtained from the MIB, as the initial bandwidth portion for initial access. In this context, the identity (ID) of the initial bandwidth portion can be considered 0. The control resource set can be referred to as a control region, control resource region, etc.

[0084] The bandwidth configuration supported by 5G can be used for a variety of purposes.

[0085] According to some embodiments, when the bandwidth supported by the UE is less than the bandwidth supported by the system bandwidth, this can be supported through bandwidth portion configuration. For example, the base station can configure the frequency position of the bandwidth portion for the UE, so that the UE can send or receive data at a specific frequency position within the system bandwidth.

[0086] According to some embodiments, to support different numbers, the base station can configure multiple bandwidth portions for the UE. For example, to support data transmission or reception for a UE using a 15 kHz subcarrier spacing and a 30 kHz subcarrier spacing, the two bandwidth portions can be configured with 15 kHz and 30 kHz subcarrier spacings, respectively. Different bandwidth portions can be frequency-division multiplexed, and the bandwidth portion configured as a subcarrier spacing can be activated when data needs to be transmitted or received at a specific subcarrier spacing.

[0087] According to some embodiments, to reduce UE power consumption, the base station can configure bandwidth portions with different bandwidth sizes for the UE. For example, if the UE supports a very large bandwidth, such as 100 MHz, and always transmits or receives data via that bandwidth, very high power consumption may occur. Specifically, in the absence of service, performing unnecessary listening on the downlink control channel with a large bandwidth of 100 MHz may be very inefficient in terms of power consumption. To reduce UE power consumption, the base station can configure a relatively small bandwidth portion for the UE, such as a 20 MHz bandwidth portion. In the absence of service, the UE can perform listening in the 20 MHz bandwidth portion, and when data is generated, the UE can transmit or receive data using the 100 MHz bandwidth portion according to the base station's instructions.

[0088] In the method for configuring the bandwidth portion, the UE, prior to RRC connection, can receive configuration information for the initial bandwidth portion via the Master Information Block (MIB) during the initial access phase. More specifically, the UE can be configured with a Control Resource Set (CORESET) for the downlink control channel, via which downlink control information (DCI) for scheduling System Information Blocks (SIBs) can be transmitted from the MIB of the Physical Broadcast Channel (PBCH). The bandwidth of the Control Resource Set configured via the MIB can be considered as the initial bandwidth portion, and the UE can receive the SIB on the Physical Downlink Shared Channel (PDSCH) via the configured initial bandwidth portion. Besides the purpose of receiving the SIB, the initial bandwidth portion can be used for other System Information (OSI), paging, and random access.

[0089] [SS / PBCH block]

[0090] The following will describe the synchronization signal (SS) / PBCH block (SSB) in 5G.

[0091] The SS / PBCH block can refer to a physical layer channel block that includes the primary SS (PSS), secondary SS (SSS), and PBCH. A detailed description follows:

[0092] PSS: Used as a reference for downlink time / frequency synchronization and provides some signals about cell ID information;

[0093] SSS: Used as a reference for downlink time / frequency synchronization and provides residual cell ID information not provided by PSS. Additionally, SSS can be used as a reference signal for PBCH demodulation.

[0094] PBCH: Provides basic system information necessary for transmitting or receiving data and control channels of the UE. Basic system information may include search space-related control information indicating radio resource mapping information for the control channel, scheduling control information on separate data channels used for transmitting system information, etc.; and

[0095] SS / PBCH Blocks: SS / PBCH blocks consist of a combination of PSS, SSS, and PBCH. One or more SS / PBCH blocks can be sent within 5ms, and each sent SS / PBCH block can be distinguished by an index.

[0096] The UE can detect the PSS and SSS during the initial access phase and can decode the PBCH. The MIB can be obtained from the PBCH, and control resource set (CORESET) #0 can be configured from it (which may correspond to a control resource set with control resource set index 0). For example, the UE can perform listening on control resource set #0, assuming (QCL assumption) that the selected SS / PBCH block and the demodulation reference signal (DMRS) transmitted in control resource set #0 are quasi-co-located (QCL). The UE can receive system information using downlink control information transmitted in control resource set #0. The UE can obtain configuration information related to the random access channel (RACH) required for initial access from the received system information. Considering the selected SS / PBCH index, the UE can send a physical RACH (PRACH) to the base station, and the base station, having received the PRACH, can obtain information about the SS / PBCH block index selected by the UE. The base station can then know that the UE has selected a block from the corresponding SS / PBCH block and is listening to the associated control resource set #0.

[0097] [DRX]

[0098] Figure 6 This is a diagram illustrating discontinuous reception (DRX).

[0099] Discontinuous Reception (DRX) in RRC Connected State is an operation where a UE using the service receives data discontinuously in RRC Connected State, where a radio link is established between the base station and the UE. DRX is also known as C-DRX. When DRX is applied, the UE turns on its receiver at specific times to listen to the control channel, and if no data is received within a specific time period, the UE turns off the receiver to reduce power consumption. DRX operation can be controlled by the MAC layer device based on various parameters and timers.

[0100] refer to Figure 6 Activity time 605 is the time during which the UE wakes up and listens to the PDCCH in each DRX cycle. Activity time 605 can be defined as follows:

[0101] drx-onDurationTimer, drx-InactivityTimer, drx-RetransmissionTimerDL, drx-RetransmissionTimerUL, or ra-ContentionResolutionTimer is running;

[0102] The scheduling request was sent on the PUCCH and is pending; or

[0103] After successfully receiving a random access response for a random access preamble not selected by the MAC entity in a contention-based random access preamble, no PDCCH indicating a new transmission addressing to the MAC entity was received.

[0104] drx-onDurationTimer, drx-InactivityTimer, drx-RetransmissionTimerDL, drx-RetransmissionTimerUL, ra-ContentionResolutionTimer, etc. are timers whose values ​​are configured by the base station and have the function of configuring the UE to listen to the PDCCH when predetermined conditions are met.

[0105] `drx-onDurationTimer` 615 is a parameter used to configure the minimum wake-up time for the UE during the DRX cycle. `drx-InactivityTimer` 620 is a parameter used to configure an additional wake-up time for the UE when a PDCCH indicating a new uplink or downlink transmission is received (630). `drx-RetransmissionTimerDL` is a parameter used to configure the maximum time during which the UE wakes up in the downlink HARQ process to receive downlink retransmissions. `drx-RetransmissionTimerUL` is a parameter used to configure the maximum time during which the UE wakes up in the uplink HARQ process to receive uplink retransmission permission. `drx-onDurationTimer`, `drx-InactivityTimer`, `drx-RetransmissionTimerDL`, and `drx-RetransmissionTimerUL` can be configured as, for example, time, the number of subframes, the number of time slots, etc. `ra-ContentionResolutionTimer` is a parameter used to listen to the PDCCH during random access.

[0106] The inactive time 610 is the time configured to not listen to the PDCCH or to not receive the PDCCH during DRX operation, and the inactive time 610 can be the remaining time after excluding the active time 605 from the total time used to perform DRX operation. If the UE does not listen to the PDCCH during the active time 605, the UE can enter a sleep or inactive state to reduce power consumption.

[0107] The DRX cycle refers to the period during which the UE wakes up and listens to the PDCCH. In other words, the DRX cycle is the duration or time interval from the first PDCCH listening by the UE to the subsequent PDCCH listening. There are two types of DRX cycles: short DRX cycles and long DRX cycles. Short DRX cycles can be optionally applied.

[0108] The long DRX period 625 is the longer of the two DRX periods configured for the UE. During long DRX operation, the UE restarts drx-onDurationTimer 615 at a point in time after the long DRX period 625 has elapsed since the start point (e.g., the start symbol) of drx-onDurationTimer 615. When operating within the long DRX period 625, the UE can start drx-onDurationTimer 615 in a slot following the drx-SlotOffset in a subframe that satisfies [Equation 1] below. Here, drx-SlotOffset refers to the delay before starting drx-onDurationTimer 615. drx-SlotOffset can be configured as, for example, time, number of slots, etc., as shown in [Equation 1] below:

[0109] [Equation 1]

[0110]

[0111] Here, for drx-LongCycleStartOffset, long DRX cycle 625 and drx-StartOffset can be used to define the subframe that starts with long DRX cycle 625. drx-LongCycleStartOffset can be configured as, for example, time, the number of subframes, the number of time slots, etc.

[0112] [PDCCH: Related to DCI]

[0113] Next, we will describe downlink control information (DCI) in a 5G system in detail.

[0114] In 5G systems, scheduling information for uplink data (or Physical Uplink Data Channel (PUSCH)) or downlink data (or Physical Downlink Data Channel (PDSCH)) is transmitted from the base station to the UE via DCI. Regarding PUSCH or PDSCH, the UE can listen to a DCI format for backoff and a DCI format for non-backoff. The DCI format for backoff may include predefined fixed fields between the base station and the UE, while the DCI format for non-backoff may include configurable fields.

[0115] DCI messages can be transmitted via the Physical Downlink Control Channel (PDCCH) through channel coding and modulation. Cyclic Redundancy Check (CRC) is appended to the DCI message payload and can be scrambled with a Radio Network Temporary Identifier (RNTI) corresponding to the UE's identity. Different RNTIs can be used depending on the purpose of the DCI message, such as UE-specific data transmission, power control commands, random access responses, etc. That is, the RNTI is not explicitly sent but is included in the CRC calculation for transmission. When a DCI message is received on the PDCCH, the UE performs a CRC check using the assigned RNTI, and if the CRC check is successful, it is determined that the message was addressed to that UE.

[0116] For example, SI-RNTI can be used to scramble the DCI for scheduling PDSCH used for System Information (SI). RA-RNTI can be used to scramble the DCI for scheduling PDSCH used for Random Access Response (RAR) messages. P-RNTI can be used to scramble the DCI for scheduling PDSCH used for paging messages. SFI-RNTI can be used to scramble the DCI for notification slot format indicator (SFI). TPC-RNTI can be used to scramble the DCI for transmit power control (TPC) notifications. Cell-RNTI (C-RNTI) can be used to scramble the DCI for scheduling UE-specific PDSCH or PUSCH.

[0117] DCI format 0_0 can be used for backoff DCI in PUSCH scheduling, where CRC can be scrambled using C-RNTI. The DCI format 0_0 with CRC scrambled using C-RNTI can include, for example, the following information.

[0118] [Table 3]

[0119]

[0120] DCI format 0_1 ​​can be used for non-back-off DCI scheduling of PUSCH, where CRC can be scrambled using C-RNTI. The DCI format 0_1 ​​with CRC scrambled using C-RNTI can include, for example, the following information.

[0121] [Table 4]

[0122]

[0123]

[0124]

[0125] DCI format 1_0 can be used to schedule the back-off DCI of PDSCH, where CRC can be scrambled with C-RNTI. The DCI format 1_0 with CRC scrambled with C-RNTI can include, for example, the following information.

[0126] [Table 5]

[0127]

[0128] DCI format 1_1 can be used for non-back-off DCI in PUSCH scheduling, where CRC can be scrambled with C-RNTI. DCI format 1_1 with CRC scrambled with C-RNTI can include, for example, the following information.

[0129] [Table 6]

[0130]

[0131]

[0132]

[0133] [PDCCH: CORESET, REG, CCE, Search Space]

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

[0135] Figure 4 This is a diagram illustrating an example of a control resource set (CORESET) for transmitting downlink control channels in a 5G wireless communication system.

[0136] Figure 4 An example is shown where the bandwidth portion 410 of the UE (UE bandwidth section) is configured on the frequency axis and two control resource sets (control resource set #1 401 and control resource set #2 402) are configured within a time slot 420 on the time axis. Control resource sets 401 and 402 can be configured for specific frequency resources within the entire UE bandwidth portion 410 on the frequency axis. Figure 4The illustration shows an example of a frequency resource 403 configured for control resource set #1 401. For a control resource set, one or more OFDM symbols can be configured on a time axis, which can be defined as the control resource duration length 404. (Reference) Figure 4 In the example shown, control resource set #1 401 is configured for a control resource set duration of 2 symbols, and control resource set #2 402 is configured for a control resource set duration of 1 symbol.

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

[0138] [Table 7]

[0139]

[0140] In [Table 7], the tci-StatesPDCCH (Transmission Configuration Indication (TCI) status) configuration information may include information about one or more Synchronization Signal (SS) / Physical Broadcast Channel (PBCH) Block (SSB) indices or Channel State Information Reference Signal (CSI-RS) indices that have a quasi-co-address (QCL) relationship with the DMRS transmitted in the corresponding control resource set.

[0141] Figure 5A This is a diagram illustrating an example of the basic units that constitute the time and frequency resources of a downlink control channel that can be used in 5G.

[0142] according to Figure 5A The basic unit of time and frequency resources constituting the control channel (PDCCH) can be called a resource element group (REG) 503, and REG 503 can be defined as one OFDM symbol 501 on the time axis and one physical resource block (PRB) 502 on the frequency axis, that is, 12 subcarriers. The base station can configure the downlink control channel allocation unit by connecting REG 503.

[0143] like Figure 5A As shown, when the basic unit used for allocating downlink control channels in 5G is a control channel element (CCE) 504, one CCE 504 can include multiple REG 503s. Figure 5ATaking REG 503 as an example, a REG 503 can include 12 REs, and if one CCE 504 includes, for example, 6 REG 503s, one CCE 504 can include 72 REs. When configuring a downlink control resource set, the corresponding area can include multiple CCE 504s, and a specific downlink control channel can be mapped to one or more CCE 504s for transmission according to the aggregation level (AL) in the control resource set. CCE 504s in the control resource set are classified by quantity, and the number of CCE 504s can be assigned according to a logical mapping scheme.

[0144] Figure 5A The basic unit of the downlink control channel shown, REG 503, can include the RE mapped to by the DCI and the area mapped to by the DMRS 505 as a reference signal for decoding the RE. Figure 5A As shown, three DMRS 505s can be transmitted within one REG 503. Depending on the aggregation level (AL), the number of CCEs required to transmit the PDCCH can be 1, 2, 4, 8, or 16, and different numbers of CCEs can be used to implement link adaptation of the downlink control channel. For example, if AL = L, a downlink control channel can be transmitted via L CCEs. The UE needs to detect signals without knowing information about the downlink control channel, where a search space representing a set of CCEs is defined for blind decoding. The search space is a set of downlink control channel candidate groups (multiple candidates) that include CCEs, for which the UE needs to attempt decoding at a given aggregation level. Due to the existence of various aggregation levels, a bundle can have 1, 2, 4, 8, or 16 CCEs, so the UE can have multiple search spaces. The search space set can be defined as a set of search spaces across all configured aggregation levels.

[0145] Search spaces can be categorized into common search spaces and UE-specific search spaces. A group of UEs or all UEs can listen to the common search space of the PDCCH to receive cell common control information, such as dynamic scheduling or paging messages for system information. For example, PDSCH scheduling allocation information for transmitting SIBs, including cell operator information, can be received by listening to the common search space of the PDCCH. In the case of a common search space, the group of UEs or all UEs need to receive the PDCCH and can therefore be defined as a pre-agreed CCE. UE-specific PDSCH or PUSCH scheduling allocation information can be received by listening to the UE-specific search space of the PDCCH. UE-specific search spaces can be defined based on the UE's identity and the functionality of various system parameters.

[0146] In 5G, the parameters of the PDCCH search space can be configured from the base station to the UE via upper-layer signaling (e.g., SIB, MIB, and RRC signaling). For example, the base station can configure to the UE the number of PDCCH candidate groups for each aggregation level L, the listening period of the search space, the listening time per symbol in the time slot of the search space, the search space type (public search space or UE-specific search space), the combination of RNTI and DCI formats to be listened to in the search space, and the control resource set index used to listen to the search space, etc. The configuration information about the PDCCH search space can include, for example, the information in [Table 8] below.

[0147] [Table 8]

[0148]

[0149] Based on the configuration information, the base station can configure one or more search space sets for the UE. According to some embodiments, the base station can configure search space set 1 and search space set 2 for the UE, configuring DCI format A scrambled with X-RNTI in search space set 1 to be listened to in a common search space, and configuring DCI format B scrambled with Y-RNTI in search space set 2 to be listened to in a UE-specific search space. In X-RNTI and Y-RNTI, "X" and "Y" can correspond to one of the various RNTIs described later.

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

[0151] In the public search space, the following combinations of DCI format and RNTI can be monitored. Of course, this disclosure is not limited to the following examples:

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

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

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

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

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

[0157] Within the UE-specific search space, the following combinations of DCI format and RNTI can be monitored. Of course, this disclosure is not limited to the following examples:

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

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

[0160] The above RNTI may meet the following definitions and purposes:

[0161] Cell RNTI (C-RNTI): Used for UE-specific PDSCH scheduling;

[0162] Temporary Cell RNTI (TC-RNTI): Used for UE-specific PDSCH scheduling;

[0163] Configured Scheduling RNTI (CS-RNTI): UE-specific PDSCH scheduling for semi-static configuration;

[0164] Random Access RNTI (RA-RNTI): Used for scheduling PDSCH during the random access phase.

[0165] Paging RNTI (P-RNTI): Used to schedule PDSCHs that send paging requests.

[0166] System Information RNTI (SI-RNTI): Used to schedule PDSCHs that send system information.

[0167] Interrupt RNTI (INT-RNTI): Used to indicate whether to punch a hole in the PDSCH;

[0168] PUSCH RNTI transmit power control (TPC-PUSCH-RNTI): used to indicate PUSCH power control commands;

[0169] PUCCH RNTI transmit power control (TPC-PUCCH-RNTI): used to indicate PUCCH power control commands; and

[0170] SRS RNTI Transmit Power Control (TPC-SRS-RNTI): Used to indicate SRS power control commands.

[0171] The aforementioned DCI format can conform to the following definition.

[0172] [Table 9]

[0173]

[0174] In 5G, the search space of the aggregation level L in the control resource set p and the search space set s can be expressed as the following [Equation 2]:

[0175] [Equation 2]

[0176] ,in

[0177] - L: Aggregation level;

[0178] - n Cl Carrier index;

[0179] - N CCE,p : The total number of existing CCEs in the control resource set p;

[0180] - Time slot index;

[0181] - : The number of PDCCH candidate groups at aggregation level L;

[0182] - : Index of PDCCH candidate groups at cluster level L;

[0183] - ;

[0184]

[0185] D = 65537; and

[0186] - n RNTI UE identity

[0187] The value of Y_(p,nμs,f) can correspond to 0 in the common search space.

[0188] In the context of a UE-specific search space, the value of Y_(p,nμs,f) can correspond to a value that varies depending on the time index and the UE's identity (either by C-RNTI or the ID configured for the UE by the base station).

[0189] In 5G, multiple search space sets can be configured using different parameters (e.g., those in [Table 8]), so the search space set that the UE listens to at each time point can vary. For example, when search space set #1 is configured in time slot X and search space set #2 is configured in time slot Y, and X and Y are different from each other, the UE can listen to search space set #1 and search space set #2 in a specific time slot, and can listen to either search space set #1 or search space set #2 in a specific time slot.

[0190] [PDCCH: Span]

[0191] When there are multiple PDCCH listening positions within a time slot, the UE can report its UE capability to the base station for each subcarrier interval. In this case, the concept of a span can be used. A span refers to consecutive symbols, where the UE can listen to PDCCH within a time slot, and each PDCCH listening position is within a span. A span can be represented as (X, Y), where X is the minimum number of symbols that can separate the first symbols of two consecutive spans, and Y is the number of consecutive symbols that can be listened to within a span. The UE can listen to the PDCCH in the interval between the first symbol of the span and symbol Y within that span.

[0192] Figure 5B This is a diagram showing, via span, the situation where a UE in a wireless communication system can have multiple PDCCH listening positions within a time slot.

[0193] refer to Figure 5B Among them, cases such as (X,Y)=(7,3), (X,Y)=(4,3) and (X,Y)=(2,2) are possible, and the three cases are shown as follows: Figure 5B Reference numerals 510, 520, and 530 are used in the figures. As an example, reference numeral 510 indicates the case where there are two spans within a time slot, which can be represented as (7, 3). The interval between the first symbols indicating the two spans is represented as X=7, the PDCCH listening position can exist within a total of Y=3 symbols starting from the first symbol of each span, and each of search spaces 1 and 2 exists within Y=3 symbols. As another example, reference numeral 520 indicates the case where there are a total of three spans in a time slot, which can be represented as (4, 3), and the interval between the second and third spans is indicated by a separation of X'=5 symbols, which is greater than X=4. Reference numeral 530 indicates the case where there are a total of seven spans in a time slot, which can be represented as (2, 2), and indicates that the PDCCH listening position can exist within a total of Y=2 symbols starting from the first symbol of each span, and search space 3 exists within Y=2 symbols.

[0194] [PDCCH: UE Capability Report]

[0195] The slot positions of the public search space and the UE-specific search space are indicated by the `monitoringSlotPeriodicityAndOffset` parameter in [Table 8], which shows the configuration information for the search space of the PDCCH, and the symbol positions within the slots are indicated by a bitmap using the `monitoringSymbolsWithinSlot` parameter in [Table 8]. The symbol positions within the slots that the UE can monitor in the search space can be reported to the base station via subsequent UE capabilities.

[0196] In one example of UE capability 1 (hereinafter referred to as "Feature Group (FG) 3-1"), UE capability 1 refers to the ability to listen for a listening position (listening time of day (MO)) within the first 3 symbols of a time slot if a listening position (listening time of day (MO)) exists in the common search space for Type 1 and Type 3 or a UE-specific search space, as shown in [Table 10] below. UE capability 1 is a mandatory capability that all UEs supporting NR can support, and whether or not UE capability 1 is supported does not need to be reported to the base station.

[0197] [Table 10]

[0198]

[0199]

[0200]

[0201] In one example of UE capability 2 (hereinafter referred to as "FG 3-2"), UE capability 2 refers to the ability to perform listening regardless of the start symbol position of the MO if a listening position (listening time of day (MO)) for the common search space or the UE-specific search space exists in the time slot, as shown in [Table 11] below. Optionally, the UE may support UE capability 2 and may report to the base station whether it supports UE capability 2.

[0202] [Table 11]

[0203]

[0204] In one example of UE capability 3 (hereinafter referred to as FG 3-5, 3-5a, and 3-5b), if multiple listening positions (listening times (MOs)) exist in a common search space or a UE-specific search space within a time slot, UE capability 3 indicates the patterns of MOs that the UE can listen to, as shown in [Table 12a] and [Table 12b] below. The MO patterns may include the interval X between the start symbols of different MOs and the maximum symbol length Y of an MO. The UE-supported combinations of (X, Y) may be one or more of, for example, {(2, 2), (4, 3), and (7, 3)}. Optionally, the UE capability may be supported by the UE, and whether the capability is supported and the aforementioned combinations of (X, Y) are explicitly reported to the base station.

[0205] [Table 12a]

[0206]

[0207]

[0208] [Table 12b]

[0209]

[0210]

[0211]

[0212] The UE can report to the base station whether it supports UE capability 2 and / or UE capability 3 as described above, along with related parameters. Based on the reported UE capabilities, the base station can perform time-axis resource allocation for the common search space and the UE-specific search space. During resource allocation, the base station can prevent the MO from being located in a position where the UE cannot perform listening.

[0213] [PDCCH: Blind Decoding (BD) / CCE Limitation]

[0214] When a UE is configured with multiple search space sets, the following conditions can be considered when determining which search space set the UE needs to monitor.

[0215] If the UE is configured with the value of monitoringCapabilityConfig-r16 via r15 monitoringcapability (i.e., upper-layer signaling), the UE can define the maximum number of PDCCH candidate groups that can be monitored and the maximum number of CCEs constituting the entire search space for each time slot (here, the entire search space can refer to the set of all CCEs corresponding to a joint area of ​​multiple search space sets). Furthermore, if the value of monitoringCapabilityConfig-r16 is configured via r16 monitoringcapability, the UE can define the maximum number of PDCCH candidate groups that can be monitored and the maximum number of CCEs constituting the entire search space for each span (here, the entire search space can refer to the set of all CCEs corresponding to a joint area of ​​multiple search space sets). The configuration information for monitoringCapabilityConfig-r16 can be found in Tables 13a and 13b below.

[0216] [Table 13a]

[0217]

[0218]

[0219] [Table 13b]

[0220]

[0221]

[0222] [Condition 1: Limit the maximum number of PDCCH candidate groups]

[0223] As described above, based on the configuration value of monitoringCapabilityConfig-r16 as upper-layer signaling, in a cell with a subcarrier spacing of 15.2 μ kHz, the maximum number of PDCCH candidate groups that the UE can monitor, Mμ, can conform to [Table 14a] below when defined based on time slots, and [Table 14b] below when defined based on span.

[0224] [Table 14a]

[0225]

[0226] [Table 14b]

[0227]

[0228] [Condition 2: Limit the maximum number of CCEs]

[0229] As described above, based on the configuration value of monitoringCapabilityConfig-r16, which is used as upper-layer signaling, in a cell with a subcarrier spacing of 15.2 μ kHz, the maximum number of CCEs constituting the entire search space (here, the entire search space can refer to the set of all CCEs corresponding to the joint area of ​​multiple search space sets) can, for example, conform to the following [Table 15a] when defined based on time slots, and conform to the following [Table 15b] when defined based on span.

[0230] [Table 15a]

[0231]

[0232] [Table 15b]

[0233]

[0234] For ease of description, the situation where conditions 1 and 2 are satisfied at a specific point in time is defined as "condition A". Therefore, not satisfying condition A can mean not satisfying at least one of conditions 1 and 2.

[0235] [PDCCH: Overbooking]

[0236] Depending on the configuration of the search space set from the base station, there may be a situation where condition A is not met at a specific time point. If condition A is not met at a specific time point, the UE can select and listen only to some search space sets that are configured to meet condition A at the corresponding time point, and the base station can send PDCCH in the selected search space set.

[0237] The method of selecting some search spaces from the set of search spaces of all configurations can conform to the following approach.

[0238] If condition A for PDCCH is not met at a specific time point (time slot), the UE (or base station) can select a search space set from the search space set existing at the corresponding time point, wherein the search space type is configured as a common search space, rather than a search space set configured as a UE-specific search space.

[0239] If all search space sets configured as common search spaces are selected (i.e., if condition A is satisfied even after selecting all search spaces configured as common search spaces), the UE (or base station) can select a search space set configured as a UE-specific search space. If multiple search space sets are configured as UE-specific search spaces, the search space set with the lower search space set index can have a higher priority. Taking priority into account, the UE (or base station) can select a UE-specific search space set within the range that condition A is satisfied.

[0240] [QCL, TCI Status]

[0241] In wireless communication systems, one or more different antenna ports can be associated with each other through a quasi-co-location (QCL) configuration as shown in Table 16 below. Different antenna ports can be replaced by one or more channels, signals, or combinations thereof; however, for convenience, different antenna ports are collectively referred to in the following description. The TCI state is used to declare / indicate the QCL relationship between a PDCCH (or PDCCH DMRS) and another RS ​​or channel, and the association of a reference antenna port A (reference RS #A) and another target antenna port B (target RS #B) indicates that the UE can apply some or all of the large-scale channel parameters estimated at antenna port A to channel measurements from antenna port B. QCL may need to associate different parameters depending on the situation, such as: 1) time tracking affected by average delay and delay spread, 2) frequency tracking affected by Doppler shift and Doppler spread, 3) radio resource management (RRM) affected by average gain, and 4) beam management (BM) affected by spatial parameters. Therefore, NR supports four types of QCL relationships, as shown in Table 16 below.

[0242] [Table 16]

[0243]

[0244] Spatial RX parameters can refer to some or all of various parameters, such as angle of arrival (AoA), power angular spectrum (PAS) of AoA, angle of departure (AoD), PAS of AoD, transmit / receive channel correlation, transmit / receive beamforming, and spatial channel correlation.

[0245] As shown in Table 17 below, QCL relationships can be configured to the UE via the RRC parameters TCI-state and QCL-information. Referring to Table 17 below, the base station can configure one or more TCT states to the UE so that the RS is notified of the ID of the reference TCI state, i.e., up to two QCL relationships (qcl-Type1 and qcl-Type2) for the target RS. Each QCL information (QCL information) included in each TCI state includes the serving cell index and BWP index of the reference RS indicated by the corresponding QCL information, the type and ID of the reference RS, and the QCL type, as shown in Table 16.

[0246] [Table 17]

[0247]

[0248] Figure 7This is a diagram illustrating an example of base station beam allocation configured according to TCI status.

[0249] refer to Figure 7 The base station can transmit information to the UE via N different beams through N different TCI states. For example, such as Figure 7 As shown, when N=3, the base station can associate the qcl-Type2 parameters included in the three TCI states 700, 705 and 710 with the CSI-RS or SSB corresponding to different beams, and be configured as QCL type D so as to announce / indicate that the antenna ports involving different TCI states 700, 705 or 710 are associated with different spatial Rx parameters (i.e. different beams).

[0250] Tables 18a to 18e below show the valid TCI state configurations based on the target antenna port type.

[0251] [Table 18a] below shows the valid TCI state configuration when the target antenna port is a CSI-RS (TRS) for tracking. TRS refers to a non-zero power (NZP) CSI-RS, where, in the CSI-RS, the repeating parameter is not configured in the configuration information shown in [Table 19a] and [Table 19b] below, and trs-Info is configured to true. Configuration 3 in [Table 18a] can be used for aperiodic TRS.

[0252] [Table 18a] Target antenna port is the effective TCI state configuration (TRS) for CSI-RS tracking.

[0253]

[0254] [Table 18b] below shows the valid TCI state configuration when the target antenna port is a CSI-RS of CSI. CSI-RS of CSI refers to NZP CSI-RS, in which parameters indicating repetition (e.g., repetition parameters) are not configured, and trs-Info is not configured to true.

[0255] [Table 18b] Effective TCI state configuration when the target antenna port is CSI-RS.

[0256]

[0257] [Table 18c] below shows the valid TCI state configuration when the target antenna port is a CSI-RS for beam management (BM) (with the same meaning as the CSI-RS for L1 reference signal received power (RSRP) reporting). The CSI-RS for BM refers to the NZP CSI-RS, where the repetition parameter is configured to have an On or Off value, and trs-Info is not configured to True.

[0258] [Table 18c] Valid TCI state configuration when the target antenna port is BM's CSI-RS (for L1 RSRP reporting)

[0259]

[0260] [Table 18d] below shows the valid TCI state configuration when the target antenna port is PDCCH DMRS.

[0261] [Table 18d] Effective TCI state configuration when the target antenna port is PDCCH DMRS.

[0262]

[0263] [Table 18e] below shows the effective TCI state configuration when the target antenna port is PDSCH DMRS.

[0264] [Table 18e] Effective TCI state configuration when the target antenna port is PDSCH DMRS.

[0265]

[0266] Representative QCL configuration methods in [Tables 18a] to [Tables 18e] include configuring and operating the target antenna port and reference antenna port for each operation as “SSB” -> “TRS” -> “CSI-RS of CSI, CSI-RS of BM, PDCCH DMRS, or PDSCH DMRS”. Based on this, the UE's reception operation can be assisted by linking the counting characteristics that can be measured from SSB and TRS to each antenna port.

[0267] For configuration information regarding trs-Info related to NZP CSI-RS, please refer to Tables 19a and 19b below.

[0268] [Table 19a]

[0269]

[0270] [Table 19b]

[0271]

[0272] [PDCCH: Related to TCI status]

[0273] Specifically, the TCI state combinations applicable to the PDCCH DMRS antenna port are shown in Table 20 below. In Table 20, the fourth row represents the combinations assumed by the UE before RRC configuration and cannot be configured after RRC configuration.

[0274] [Table 20]

[0275]

[0276] In NR, such as Figure 8 The layered signaling method shown is supported for dynamic allocation of PDCCH beams.

[0277] Figure 8 This is a diagram illustrating an example of a TCI state allocation method for a PDCCH in a wireless communication system according to an embodiment of the present disclosure.

[0278] refer to Figure 8 The base station can configure more than 825 TCI states 805, 810, ..., 820 to the UE via RRC signaling 800, and some TCI states can be configured as CORESET TCI states. The base station can then indicate 845 TCI states 830, 835, ..., 840 to the UE via MAC control unit (MACCE) signaling. Subsequently, the UE receives the PDCCH based on the beam information included in the TCI states indicated by the MAC CE signaling.

[0279] Figure 9 This is a diagram illustrating the TCI indication MACCE signaling structure for PDCCH DMRS in a wireless communication system according to an embodiment of the present disclosure.

[0280] refer to Figure 9 The TCI indication MAC CE signaling used for PDCCH DMRS is configured, for example, by 2 bytes (16 bits) (Oct1 900 and Oct2 905), and includes a 5-bit serving cell ID 915, a 4-bit CORESETID 920, and a 7-bit TCI status ID 925.

[0281] Figure 10 This is a diagram illustrating an example of the CORESET and search space beam configuration in a wireless communication system according to an embodiment of the present disclosure.

[0282] Reference Figure 10The base station can indicate 1005, one of the TCI state lists included in the CORESET1000 configuration, to the UE via MAC CE signaling. Then, until another TCI state is indicated to the corresponding CORESET via another MAC CE signaling from the base station, the UE considers the same QCL information (beam #1) 1005 to be applied to, for example, all or one search spaces #1 1010, #2 1015, and #3 1020 connected to the CORESET. In the aforementioned PDCCH beam allocation method, it is difficult to indicate beam changes that are delayed faster than MAC CE signaling, and since the same beam is applied to all CORESETs regardless of search space characteristics, flexible PDCCH beam operation may be difficult.

[0283] In the following description, embodiments of this disclosure provide more flexible PDCCH beam configurations and operating methods. Several different examples are provided for ease of description in depicting embodiments of this disclosure; however, the embodiments shown are not mutually exclusive, and two or more embodiments can be applied by appropriate combination as needed.

[0284] The base station can configure one or more TCI states for a UE for a specific control resource set, and can activate one of the configured TCI states via a MACCE activation command. For example, {TCI state #0, TCI state #1, TCI state #2} can be configured as the TCI state of control resource set #1, and the base station can send a command to the UE via MAC CE to activate the TCI state assuming TCI state #0 is the TCI state of control resource set #1. Based on the activation command of the TCI state already received via MAC CE, the UE can correctly receive the DMRS of the corresponding control resource set based on the QCL information within the activated TCI state.

[0285] For a control resource set with index configured as 0 (control resource set #0), if the UE fails to receive a MAC CE activation command for the TCI state of control resource set #0, the UE may assume (QCL assumption) that the DMRS sent in control resource set #0 is quasi-co-located with the SS / PBCH block (SSB) identified during initial access or during non-contention-based random access not triggered by a PDCCH command.

[0286] Regarding the control resource set (control resource set #X) whose index is configured to a value other than 0, if the UE is not configured with a TCI state for control resource set #X, or has received one or more TCI states but has not received a MAC CE activation command to activate one of the received TCI states, the UE may assume (QCL assumption) that the DMRS sent in control resource set #X is quasi-co-located with the SS / PBCH block (SSB) identified during initial access.

[0287] [PDSCH: Related to frequency resource allocation]

[0288] Figure 11 This is a diagram illustrating an example of frequency domain resource allocation for a Physical Downlink Shared Channel (PDSCH) in a wireless communication system according to an embodiment of the present disclosure.

[0289] Figure 11 Three frequency axis resource allocation methods are shown, which can be dynamically switched via resource allocation (RA) type 0 1110, RA type 1 1120 and resource allocation (RA type 0 and RA type 1) 1130 configured in the upper layer of the NR wireless communication system.

[0290] refer to Figure 11 If the UE is configured to use only RA type 0 1110 for upper-layer signaling, then a portion of the downlink control information (DCI) used to allocate PDSCH to the UE includes, for example, a bitmap 1111 that includes NRBG bits. The conditions for this situation will be described later. In this case, NRBG refers to the number of resource block groups (RBGs) determined according to the rbg-Size as an upper-layer parameter and the BWP size allocated by the BWP indicator, as shown in [Table 21] below, and data is transmitted via the bitmap on the RBG indicated by the number 1.

[0291] [Table 21]

[0292]

[0293] If the UE is configured to use only RA type 1 1120 via upper-layer signaling, a portion of the DCI used to allocate PDSCH to the UE includes... Bit frequency axis resource allocation information. This refers to the number of RBs (BWP) in the downlink bandwidth portion. The conditions for this situation will be described later. Based on this, the base station can configure the starting virtual resource block (VRB) 1121 and the length 1123 of the frequency domain resources continuously allocated from it.

[0294] If the UE is configured via upper-layer signaling to use RA type 0 and RA type 1 as in 1130, a portion of the DCI used to allocate PDSCH to the UE includes Frequency Domain Resource Allocation (FDRA) information. This information includes bits 1121 and 1123 for configuring RA type 11120 and the larger value 1133 of the payload 1111 for configuring RA type 0 1110. The conditions for this situation will be described later. In this case, a bit 1131 can be added to the first part (MSB) of the Frequency Domain Resource Allocation information in the DCI to indicate the use of RA type 0 or RA type 1. For example, if the value of bit 1131 is "0", it can indicate the use of RA type 0, and if the value is "1", it can indicate the use of RA type 1.

[0295] [Involves PDSCH time resource allocation]

[0296] The following section describes a time-domain resource allocation (TDRA) method for data channels in next-generation mobile communication systems (5G or NR systems).

[0297] The base station can configure tables for time-domain resource allocation information for downlink data channels (Physical Downlink Shared Channel (PDSCH)) and uplink data channels (Physical Uplink Shared Channel (PUSCH)) to the UE via upper-layer signaling (e.g., RRC signaling). A table with up to 16 entries (maxNrofDL-Allocations=16) can be configured for the PDSCH, and a table with up to 16 entries (maxNrofUL-Allocations=16) can be configured for the PUSCH. In an embodiment, time-domain resource allocation information may include time slot timing from PDCCH to PDSCH (denoted as K0, and corresponding to the time interval of time slot units between the time point of receiving PDCCH and the time point of sending PDSCH scheduled by the received PDCCH), time slot timing from PDCCH to PUSCH (denoted as K2, and corresponding to the time interval of time slot units between the time point of receiving PDCCH and the time point of sending PUSCH scheduled by the received PDCCH), information regarding the position and length of the start symbol for scheduling PDSCH or PUSCH within a time slot, the mapping type of PDSCH or PUSCH, etc. For example, information as shown in [Table 22] or [Table 23] below can be sent from the base station to the UE.

[0298] [Table 22]

[0299]

[0300] [Table 23]

[0301]

[0302] The base station can notify the UE of one of the entries in [Table 22] and [Table 23] of time-domain resource allocation information via L1 signaling (e.g., DCI). (For example, the entry can be indicated by the "Time-domain Resource Allocation" field in the DCI). The UE can obtain the time-domain resource allocation information of PDSCH or PUSCH based on the DCI received from the base station.

[0303] Figure 12 This is a diagram illustrating an example of time-domain resource allocation for a PDSCH in a wireless communication system according to an embodiment of the present disclosure.

[0304] Reference Figure 12 The base station can indicate the temporal location of the PDSCH resource based on the subcarrier spacing (SCS) (μPDSCH and μPDCCH) of the data channel and control channel configured using upper-layer signaling, the scheduling offset (K0) value, and the OFDM symbol start position 1203 and length (L) 1205 in a time slot 1201 dynamically indicated by DCI.

[0305] Figure 13 This is a diagram illustrating an example of time-domain resource allocation based on the subcarrier spacing of the data channel and the control channel in a wireless communication system according to an embodiment of the present disclosure.

[0306] Reference Figure 13 If the subcarrier spacing (SCS) (μPDSCH and μPDCCH) of the data channel and control channel are the same (μPDSCH = μPDCCH), then the time slot numbers for data and control are the same. Therefore, the base station and UE can generate a scheduling offset based on a predetermined time slot offset K0. On the other hand, if the subcarrier spacing (SCS) (μPDSCH and μPDCCH) of the data channel and control channel are different (μPDSCH ≠ μPDCCH), then the time slot numbers used for data and control are different. Therefore, the base station and UE can generate a scheduling offset based on the subcarrier spacing of the PDCCH and a predetermined time slot offset K0. For example, if the UE has already received a DCI indicating a change in bandwidth in time slot n, and the time slot offset value indicated by the DCI is K0, then data can be received in the PDSCH scheduled in time slot n+K0.

[0307] [UE Capability Report]

[0308] In LTE and NR systems, when a UE is connected to a serving base station, the UE can perform a process of reporting its supported capabilities to the base station. In the following description, this is referred to as UE capability reporting.

[0309] A base station can transmit a UE capability query message to a connected UE to request a capability report. This message can include UE capability requests for each Radio Access Technology (RAT) type of the base station. Requests for each RAT type can include information such as supported frequency band combinations. In the case of a UE capability query message, UE capabilities for multiple RAT types can be requested via a container of a single RRC message sent by the base station, or the base station can include multiple UE capability query messages containing UE capability requests for each RAT type to transmit to the UE. That is, the UE capability query is repeated multiple times within a single message, and the UE can configure the corresponding UE capability information message and report the same message multiple times. In next-generation mobile communication systems, UE capability requests can be made for multiple RAT dual connectivity (MR-DC) UEs, including NR, LTE, and E-UTRA-NR dual connectivity (EN-DC). UE capability query messages are typically initially sent after the UE connects to the base station, but the base station can request a UE capability report under any conditions if necessary.

[0310] As described above, a UE that has received a request for a UE capability report from the base station configures its capabilities based on the RAT type and frequency band information requested from the base station. An example of how a UE configures its capabilities in an NR system is as follows.

[0311] If the UE receives a list of LTE and / or NR bands via a request for UE capabilities from the base station, the UE configures a band combination (BC) for EN-DC and NR Independent (SA). That is, the UE configures a candidate list of BCs for EN-DC and NR SA based on the bands requested by the base station via FreqBandList. The bands are prioritized according to the order described in the FreqBandList.

[0312] If the base station sets the "eutra-nr-only" or "eutra" flag in the UE capability query message to request a UE capability report, the UE will be completely removed from the configured BC candidate list. This may only occur when the LTE base station (eNB) requests the "eutra" capability.

[0313] Next, the UE removes the fallback BC from the configured BC candidate list. Here, a fallback BC is a BC that can be obtained by removing the band corresponding to at least one SCell from any BC, and this can be omitted since the BC before removing the band corresponding to at least one SCell can already cover the fallback BC. This operation also applies to MR-DC, i.e., LTE bands. The BCs remaining after this operation constitute the final "candidate BC list".

[0314] The UE selects the BC to report by choosing a BC that matches the requested RAT type from the final "Candidate BC List". In this operation, the UE configures the supportedBandCombinationList in a predetermined order. That is, the UE configures the BCs to be reported and UE capabilities according to a pre-configured RAT type order (NR -> EUTRA-NR -> EUTRA). The UE configures featureSetCombinations for the configured supportedBandCombinationList and configures a list of "Candidate Feature Set Combinations" from the candidate BC list, from which a list of fallback BCs (including capabilities of equal or lower level) has been removed. "Candidate Feature Set Combinations" can include feature set combinations of NR and EUTRA-NR BCs, and can be obtained from feature set combinations of UE-NR capabilities and UE-MRDC capability containers.

[0315] If the requested RAT type is eutra-nr and has an impact, featureSetCombinations are included in both containers for the UE-MRDC capability and the UE-NR capability. However, the NR feature set is only included in the UE-NR capability.

[0316] After configuring UE capabilities, the UE transmits a UE capability information message, including the UE capabilities, to the operating base station. Based on the UE capabilities received from the UE, the base station performs appropriate scheduling and transmission or reception management for the corresponding UE at a later time.

[0317] [Related to CA / DC]

[0318] Figure 14 This is a diagram illustrating the radio protocol structure of the base station and UE in the cases of single cell 1410, carrier aggregation 1420, and dual connectivity 1430 according to embodiments of the present disclosure.

[0319] Reference Figure 14 The radio protocols of next-generation mobile communication systems include NR Service Data Adaptation Protocol (SDAP) S25 and S70, NR Packet Data Convergence Protocol (PDCP) S30 and S65, NR Radio Link Control (RLC) S35 and S60, and NR Media Access Control (MAC) layers S40 and S55, respectively, in the UE and NR base station. In the following description, each layer device can be understood as a functional block responsible for the corresponding layer.

[0320] The main functions of NR SDAP S25 and S70 may include the following:

[0321] User data transmission function (transmission of user plane data);

[0322] The function of mapping uplink and downlink QoS flows and data bearers (mapping between QoS flows and DRBs of DL and UL).

[0323] The ability to mark QoS flow IDs in both uplink and downlink (marking QoS flow IDs in DL and UL packets); and / or

[0324] The function of mapping reflected QoS streams to the data bearers of uplink SDAP PDUs (DRB mapping of reflected QoS streams to ULSDAP PDUs).

[0325] Regarding SDAP layer devices, the UE can be configured via RRC messages to use either the SDAP layer device header or the SDAP layer device functionality for each PDCP layer device, each bearer, or each logical channel. If the SDAP header is configured, the NAS QoS reflection configuration 1-bit indicator (NAS reflected QoS) and AS QoS reflection configuration 1-bit indicator (AS reflected QoS) in the SDAP header can instruct the UE to update or reconfigure the mapping information of data bearers and QoS flows in the uplink and downlink. The SDAP header may include QoS flow ID information indicating QoS. QoS information can be used for data processing priority, scheduling information, etc., to support smooth service.

[0326] The main functions of NR PDCP 10-30 and 10-65 may include the following:

[0327] Header compression and decompression functions (header compression and decompression: ROHC only);

[0328] User data transmission function (transmitting user data);

[0329] Ordered delivery function (ordered delivery of upper-layer PDUs);

[0330] Out-of-order delivery function (out-of-order delivery of upper-layer PDUs);

[0331] Reordering function (for reordering received PDCP PDUs).

[0332] Duplicate detection function (duplicate detection of lower-level SDUs);

[0333] Retransmission function (PDCP SDU retransmission);

[0334] Encryption and decryption functions (encryption and decryption); and / or

[0335] Timer-based SDU deletion function (timer-based SDU discarding in the uplink).

[0336] The NR PDCP reordering function refers to the function of reordering PDCP PDUs received from the lower layer in sequence based on the PDCP sequence number (SN), and may include the function of transmitting data to the upper layer according to the reordered sequence. Optionally, the NR PDCP reordering function may include the function of transmitting directly without considering the sequence, the function of reordering the sequence to record lost PDCP PDUs, the function of reporting the status of lost PDCP PDUs to the transmitting side, and the function of requesting the retransmission of lost PDCP PDUs.

[0337] The main functions of NR RLC S35 and S60 may include the following:

[0338] Data transmission function (transmission of upper-layer PDUs);

[0339] Ordered delivery function (ordered delivery of upper-layer PDUs);

[0340] Out-of-order delivery function (out-of-order delivery of upper-layer PDUs);

[0341] ARQ function (correction via ARQ);

[0342] splicing, segmentation, and reassembly functions (RLC SDU splicing, segmentation, and reassembly);

[0343] Re-segmentation function (re-segmentation of RLC data PDUs);

[0344] Reordering function (reordering RLC data PDUs);

[0345] Duplicate detection function (duplicate detection);

[0346] Error detection function (protocol error detection);

[0347] RLC SDU discard function (RLC SDU discard); and / or

[0348] RLC Reconstruction Function (RLC Reconstruction).

[0349] The ordered delivery function of NR RLC can refer to the function of sequentially transmitting RLC SDUs received from the lower layer to the upper layer. The ordered delivery function of NR RLC can include the function of reassembling and transmitting RLC SDUs when an initial RLC SDU is fragmented into multiple RLC SDUs and subsequently received; the function of reordering received RLC PDUs according to the RLC sequence number (SN) or PDCP sequence number (SN); the function of reordering the sequence and recording lost RLC PDUs; the function of reporting the status of lost RLC PDUs to the transmitting side; and the function of requesting retransmission of lost RLC PDUs. The ordered delivery function of NR RLC can include the function of sequentially transmitting only the RLC SDUs preceding the lost RLC SDU to the upper layer when a lost RLC SDU exists, or the function of sequentially transmitting all received RLC SDUs to the upper layer before a predetermined timer starts, even if a lost RLC SDU exists. Alternatively, the ordered delivery function of the NR RLC device may include the ability to sequentially deliver all RLCSDUs received up to the current time to the upper layer, even if lost RLC SDUs exist, if a predetermined timer expires. RLC PDUs can be processed in the order they are received (according to arrival order, regardless of sequence number or order of sequence number) and can be transmitted to the PDCP device regardless of order (out-of-order delivery). In the case of segmentation, segments stored in a buffer or to be received later can be received, reconfigured into a complete RLC PDU, processed, and then transmitted to the PDCP device. The NR RLC layer may not include splicing functionality, and this functionality can be performed in the NR MAC layer, or replaced by multiplexing functionality of the NR MAC layer.

[0350] The out-of-order delivery function of an NR RLC device refers to the function of transmitting RLC PDUs received from a lower layer to the immediately adjacent upper layer in any order. It may include the function of reassembling and transmitting RLC SDUs when an initial RLC SDU is segmented into multiple RLC SDUs and then received, and may include the function of storing the RLC SN or PDCP SN of the received RLC PDUs, arranging their order, and recording lost RLC PDUs.

[0351] NR MAC S40 or S55 can connect to multiple NR RLC layer devices included in a single UE, and the main functions of NR MAC can include some of the following:

[0352] Mapping function (mapping between logical channels and transport channels);

[0353] Multiplexing and demultiplexing functions (MAC SDU multiplexing / demultiplexing);

[0354] Dispatch information reporting function (dispatch information report);

[0355] HARQ function (correction via HARQ);

[0356] Priority processing function between logical channels (priority processing between logical channels of a UE).

[0357] Priority processing function between UEs (priority processing between UEs is performed through dynamic scheduling).

[0358] MBMS service identification function (MBMS service identification);

[0359] Transmission format selection function (transmission format selection); and / or

[0360] Fill function (fill).

[0361] The NR PHY layers S45 and S50 can perform channel coding and modulation of upper-layer data, convert the channel-coded and modulated upper-layer data into OFDM symbols, and transmit the OFDM symbols via a radio channel. Alternatively, they can perform demodulation and channel decoding of OFDM symbols received via a radio channel and transmit them to the upper layer.

[0362] The detailed structure of a radio protocol can vary depending on the operator's (or cell's) operating methods. For example, when a base station transmits data to a UE based on a single carrier (or cell), such as... Figure 14 As shown by reference numeral 1410 in the figure, the base station and the UE use a protocol structure with a single structure at each layer. On the other hand, when the base station transmits data to the UE, based on carrier aggregation (CA) using multiple carriers in a single TRP, the base station and the UE use a protocol structure in which a single structure is provided up to the RLC layer, but the PHY layer is multiplexed via the MAC layer, as shown by reference numeral 1420. As another example, when the base station transmits data to the UE based on dual connectivity (DC) using multiple carriers in multiple TRPs, the base station and the UE use a protocol structure in which a single structure is provided up to the RLC layer and the PHY layer are multiplexed via the MAC layer, as shown by reference numeral 1430.

[0363] Referring to the above description regarding PDCCH and beam configuration, Rel-15 and Rel-16 NR currently do not support PDCCH retransmission, making it difficult to achieve the required reliability in scenarios requiring high reliability, such as URLLC. This disclosure provides a method for PDCCH retransmission via multiple transmission points (TRP), thereby improving the reliability of UE PDCCH reception. The specific method is described in detail in the following embodiments.

[0364] This disclosure applies to at least one of FDD and TDD systems. In the following, in this disclosure, higher signaling (or upper-layer signaling) is a method of transmitting signals from a base station to a UE using a physical layer downlink data channel or from a UE to a base station using a physical layer uplink data channel, and may be referred to as RRC signaling, PDCP signaling, or Media Access Control (MAC) CE.

[0365] In the following, within this disclosure, the UE may use various methods to determine whether cooperative communication is applied, including assigning a PDSCH(s) to which cooperative communication is applied with a specific format, assigning a PDSCH(s) to which cooperative communication is applied with a specific indicator including a specific indicator indicating whether cooperative communication is applied, assigning a PDSCH(s) to which cooperative communication is applied with a specific RNTI for scrambling, or assuming that cooperative communication is applied in a specific part indicated by the upper layer, etc. For ease of description, the case in which the UE receives a PDSCH to which cooperative communication is applied based on conditions similar to those described above will be referred to as the incoherent joint transmission (NC-JT) case.

[0366] In the following, in this disclosure, the determination of the priority between A and B may be referred to in various ways, such as selecting the one with higher priority to perform the corresponding operation according to a predetermined priority rule, or omitting or discarding the operation with lower priority.

[0367] In the following description of the foregoing examples, various embodiments will be provided, but these embodiments are not independent embodiments, and one or more embodiments may be applied simultaneously or in combination.

[0368] [Related to NC-JT]

[0369] According to embodiments of this disclosure, noncoherent joint transmission (NC-JT) can be used by a UE to receive PDSCH from multiple transmit and receive points (TRPs).

[0370] Unlike traditional systems, 5G wireless communication systems can support services requiring high transmission rates, as well as services with very low transmission latency and high connection density. In wireless communication networks comprising multiple cells, TRPs, or beams, cooperative communication (coordinated transmission) between cells, TRPs, and / or beams can meet various service requirements by enhancing the strength of the signal received by the UE or effectively implementing interference control between cells, TRPs, and / or beams.

[0371] Joint transmission (JT) is a representative transmission technology used for the aforementioned cooperative communication, and it is a technique that increases the strength or throughput of the signal received by the UE by transmitting signals to a UE via multiple different cells, TRPs, and / or beams. The channels between the UE and each cell, TRP, and / or beam may have significantly different characteristics. Specifically, noncoherent joint transmission (NC-JT) that supports non-interference coding between cells, TRPs, and / or beams may require separate precoding, MCS, resource allocation, TCI indication, etc., depending on the channel characteristics of the corresponding links between the UE and the corresponding cells, TRPs, and / or beams.

[0372] The aforementioned NC-JT transmission can be applied to at least one of the downlink data channel (PDSCH), downlink control channel (PDCCH), uplink data channel (PUSCH), and uplink control channel (PUCCH). During PDSCH transmission, transmission information such as precoding, modulation and coding scheme (MCS), resource allocation, and transmission configuration indication (TCI) is indicated by the DLDCI, and for NC-JT transmission, the transmission information can be indicated independently for each cell, TRP, and / or beam. This becomes a major factor increasing the payload required for DL ​​DCI transmission, which may adversely affect the reception performance of DCI in PDCCH transmission. Therefore, to support JT in PDSCH, it is necessary to carefully design the tradeoff between DCI information content and control information reception performance.

[0373] Figure 15 This is a diagram illustrating an example of antenna port configuration and resource allocation for transmitting PDSCH using cooperative communication in a wireless communication system according to an embodiment of the present disclosure.

[0374] refer to Figure 15 An example of PDSCH transmission is described for each Joint Transmission (JT) technology, and an example of radio resource allocation for each TRP is shown.

[0375] Reference Figure 15 Example 1510 shows coherent joint transmission (C-JT) that supports phase interference coding between individual cells, TRPs and / or beams.

[0376] In the C-JT scenario, TRP A 1511 and TRP B 1513 send a single data transmission (PDSCH) to UE 1515, and joint precoding can be performed across multiple TRPs. This can be instructed to transmit DMRS through the same DMRS port so that TRP A 1511 and TRP B 1513 transmit the same PDSCH. For example, TRP A 1511 and TRP B 1513 can send DRMS ​​to the UE through DMRS port A and DMRS port B, respectively. In this case, the UE can receive a DCI message for receiving a PDSCH based on DMRS demodulation transmitted through DMRS port A and DMRS port B.

[0377] Figure 15 Example 1520 of Noncoherent Joint Transmission (NC-JT) is shown, which supports noncoherent coding between individual cells, TRPs and / or beams for PDSCH transmission.

[0378] In the NC-JT scenario, PDSCH is transmitted to UE 1525 for each cell, TRP, and / or beam, and individual precoding can be applied to each PDSCH. This can instruct DMRS to be transmitted through different DMRS ports, so that TRP A 1521 and TRP B 1523 transmit different PDSCHs. For example, TRP A 1521 can transmit DRMS ​​to the UE through DMRS port A, and TRP B 1523 can transmit DRMS ​​to the UE through DMRS port B. The UE can receive DCI information to receive each PDSCH demodulated based on DMRS transmitted through DMRS port A and DMRS port B, respectively. Transmitting different PDSCH layers or different PDSCHs to the UE for each cell, TRP, and / or beam improves throughput compared to single-cell, TRP, and / or beam transmission. Repeatedly transmitting the same PDSCH to the UE for each cell, TRP, and / or beam improves reliability compared to single-cell, TRP, and / or beam transmission. For ease of description, cells, TRPs, and / or beams are collectively referred to as TRPs in the following text.

[0379] exist Figure 15 In the embodiments, various radio resource allocations can be considered, such as the case 1530 where multiple TRPs use the same frequency and time resources for PDSCH transmission, the case 1540 where the frequency and time resources used by multiple TRPs do not overlap at all, and the case 1550 where some frequency and time resources used by multiple TRPs overlap.

[0380] To simultaneously assign multiple PDSCHs to a single UE to support NC-JT, various types, structures, and relationships of DCIs can be considered.

[0381] Figure 16 This is a diagram illustrating an example of the configuration of downlink control information (DCI) of an NC-JT in a wireless communication system according to an embodiment of the present disclosure, wherein each TRP sends different PDSCHs or different PDSCH layers to the UE.

[0382] Reference Figure 16 Case #1 1610 is an example where, in addition to the serving TRP (TRP #0) used during a single PDSCH transmission, (N-1) different PDSCHs are transmitted from (N-1) additional TRPs (TRP #1 to TRP #(N-1)). The control information for the PDSCHs transmitted in the (N-1) additional TRPs is transmitted independently of the control information for the PDSCHs transmitted in the serving TRP. That is, the UE can obtain the control information for the PDSCHs transmitted from different TRPs (TRP #0 to TRP #(N-1)) via independent DCIs (DCI #0 to DCI #(N-1)). The formats of the independent segments of the DCIs can be the same or different from each other, and the payloads between the DCIs can also be the same or different from each other. In the aforementioned Case #1 1610, the freedom of control or allocation for each PDSCH can be fully guaranteed; however, if the corresponding DCIs are transmitted in different TRPs, coverage differences occur for each DCI, and reception performance may be degraded as a result.

[0383] Case #2 1620 shows an example depending on the control information (DCI#0) used for PDSCH, in which (N-1) different PDSCHs are sent from (N-1) additional TRPs (TRP #1 to TRP #(N-1)) in addition to the serving TRP (TRP#0) used during a single PDSCH transmission, control information (DCI) for the PDSCHs of the (N-1) additional TRPs is sent separately, and each DCI (sDCI#0 to sDCI#(N-2)) is sent from the serving TRP.

[0384] For example, DCI#0, which is the control information for PDSCH sent from the serving TRP (TRP#0), includes all the information elements of DCI format 1_0, DCI format 1_1, and DCI format 1_2. However, the shortened DCI (hereinafter referred to as sDCI) (sDCI#0 to sDCI#(N-2)) for the control information of PDSCH sent from the cooperating TRPs (TRP #1 to TRP#(N-1)) may only include some of the information elements of DCI format 1_0, DCI format 1_1, and DCI format 1_2. Therefore, in the case of sDCI used to transmit control information for PDSCH sent from the cooperating TRP, the payload is smaller compared to the normal DCI (nDCI) used to transmit control information related to PDSCH sent from the serving TRP, and therefore, reserved bits may be included when compared to nDCI.

[0385] In the aforementioned case #2 1620, the control or allocation degrees of freedom for each PDSCH can be restricted based on the content of the information elements included in the sDCI. However, since the reception performance of the sDCI is better than that of the nDCI, the probability of coverage differences for each DCI can be reduced.

[0386] exist Figure 16 Case #3 1630 illustrates an example of control information (DCI) depending on the PDSCH, in which (N-1) different PDSCHs are sent from (N-1) additional TRPs (TRP #1 to TRP #(N-1)) in addition to the serving TRP (TRP #0) used during a single PDSCH transmission, a control information (sDCI) for the PDSCHs of (N-1) additional TRPs is sent, and the DCI is sent from the serving TRP.

[0387] For example, DCI#0, which is the control information for PDSCH transmitted from the serving TRP (TRP#0), includes all information elements of DCI format 1_0, DCI format 1_1, and DCI format 1_2. In the case of control information for PDSCH transmitted from cooperative TRPs (TRP#1 to TRP#(N-1)), only some information elements of DCI format 1_0, DCI format 1_1, and DCI format 1_2 can be collected in a "secondary" DCI (sDCI) for transmission. For example, the sDCI may include at least one HARQ-related information, such as frequency domain resource allocation, time domain resource allocation, and the MCS of the cooperative TRP. Furthermore, information not included in the sDCI, such as the bandwidth portion (BWP) indicator or carrier indicator, may be based on the serving TRP's DCI (DCI#0, normal DCI, or nDCI).

[0388] exist Figure 16In case #3 1630, the control or allocation degrees of freedom of each PDSCH can be restricted according to the content of the information elements included in the sDCI, but the sDCI reception performance can be adjusted, and the complexity of blind decoding of the UE's DCI can be reduced compared to case #1 1610 or case #2 1620.

[0389] exist Figure 16 Case #4 1640 is an example where, in addition to the serving TRP (TRP #0) used during a single PDSCH transmission, (N-1) different PDSCHs are sent from (N-1) additional TRPs (TRP #1 to TRP #(N-1)). The control information for the PDSCHs sent from the (N-1) additional TRPs is transmitted in the same DCI (long DCI) used for transmitting the PDSCHs sent from the serving TRP. That is, the UE can obtain the control information for the PDSCHs sent from different TRPs (TRP #0 to TRP #(N-1)) via a single DCI. In Case #4 1640, the complexity of the UE's blind DCI decoding may not increase, but the freedom of PDSCH control or allocation may be lower, thus limiting the number of cooperating TRPs based on the long DCI payload constraints.

[0390] In the following description and embodiments, sDCI may refer to various auxiliary DCIs, such as shortened DCIs, auxiliary DCIs, and normal DCIs that include PDSCH control information sent in the coordinated TRP (the aforementioned DCI formats 1_0 to 1_1), and unless a specific limitation is specified, the description also applies to various auxiliary DCIs.

[0391] In the following description and embodiments, cases #1 1610, #2 1620, and #3 1630, where one or more DCIs (PDCCHs) are used for NC-JT support, are classified as multiple PDCCH-based NC-JTs, and case #4 1640, where a single DCI (PDCCH) is used for NC-JT support, can be classified as a single PDCCH-based NC-JT. In multiple PDCCH-based PDSCH transmissions, the CORESET of the DCI for the scheduling service TRP (TRP#0) and the CORESET of the DCI for the scheduling cooperation TRPs (TRP#1 to TRP#(N-1)) can be distinguished. Methods for distinguishing CORESETs include methods such as using an upper-layer indicator for each CORESET, methods using beam configuration for each CORESET, etc. In a single PDCCH-based NC-JT, a single DCI schedules a single PDSCH with multiple layers, rather than scheduling multiple PDSCHs, and these multiple layers can be transmitted from multiple TRPs. In this case, the connection between the layer and the TRP used to transmit that layer can be indicated via the Transmission Configuration Indicator (TCI) of that layer.

[0392] In embodiments of this disclosure, when applied in practice, “Cooperative TRP” can be replaced with various terms such as “cooperative panel” or “cooperative beam”.

[0393] In the embodiments of this disclosure, "when NC-JT is applied" can be interpreted in various ways according to situations such as "when the UE receives one or more PDSCHs simultaneously in a BWP", "when the UE receives PDSCHs simultaneously in a BWP based on two or more Transport Configuration Indicators (TCIs)", "when the PDSCHs received by the UE are associated with one or more DMRS port groups", etc., but for ease of description, it is used as an expression.

[0394] In this disclosure, the NC-JT radio protocol architecture can be used in various ways depending on the TRP deployment scenario. For example, if there is no backhaul delay or a very small backhaul delay between cooperating TRPs, a similar approach can be used. Figure 14 The method based on MAC layer multiplexing (similar to the CA method) shown in Figure 1420 is possible. On the other hand, if the backhaul delay between cooperative TRPs is too large to be ignored (e.g., when information exchange such as CSI, scheduling, and HARQ-ACK between cooperative TRPs requires 2 ms or more), similar to... Figure 14 As shown in Figure 1430, it is possible to ensure delay robustness by using an independent structure for each TRP from the RLC layer (similar to the DC method).

[0395] UEs supporting C-JT / NC-JT can receive C-JT / NC-JT related parameters and settings from the upper-layer configuration, and can set the UE's RRC parameters accordingly. For upper-layer configuration, the UE can utilize, for example, tci-StatePDSCH as a UE capability parameter. For PDSCH transmission purposes, tci-StatePDSCH can define TCI states. The number of TCI states can be configured as 4, 8, 16, 32, 64, and 128 in FR1, and as 64 and 128 in FR2. Up to eight states can be configured, indicated by three bits of the TCI field in the DCI via the MAC CE message. The maximum value of 128 refers to the value indicated by maxNumberConfiguredTCIstatesPerCC in the tci-StatePDSCH parameter included in the UE's capability signaling. In this way, a series of configuration procedures from upper-layer configuration to MAC CE configuration can be applied to beamforming change commands or beamforming indications for at least one PDSCH in a TRP.

[0396] [Multi-DCI-based Multi-TRP]

[0397] According to embodiments of this disclosure, downlink control channels for NC-JT transmission can be configured based on multiple PDCCHs.

[0398] In multiple PDCCH-based NC-JTs, when sending the DCI for the PDSCH schedule of each TRP, there may be a CORESET or search space for each TRP. The CORESET or search space for each TRP can be configured as at least one of the following examples.

[0399] In one example of the upper-level index configuration for each CORESET, the CORESET configuration information via the upper-level configuration can include an index value, and the TRP used to transmit PDCCH from the corresponding CORESET can be distinguished by the index value configured for each CORESET. That is, in a group of CORESETs with the same upper-level index value, it can be assumed that the same TRP sends PDCCH or that the PDCCH of the same TRP schedules PDSCH. The above index for each CORESET can be named CORESETPoolIndex, and for CORESETs configured with the same CORESETPoolIndex value, it can be assumed that the PDCCH is sent from the same TRP. In the case of a CORESET without a configured CORESETPoolIndex value, it can be assumed that the default value of CORESETPoolIndex is configured, where the default value can be 0.

[0400] In one example of multiple PDCCH configurations, multiple PDCCH configurations can be configured within a single BWP, and each PDCCH configuration can include a PDCCH configuration for each TRP. That is, the list of CORESETs and / or the list of search spaces for each TRP can be configured in a single PDCCH configuration, and one or more CORESETs and one or more search spaces included in a PDCCH configuration can be considered to correspond to a specific TRP.

[0401] In one example of CORESET beam / beam group configuration, the TRP corresponding to a given CORESET can be distinguished by the beam or beam group configured for each CORESET. For example, when multiple CORESETs are configured with the same TCI state, it can be assumed that the corresponding CORESETs are transmitted via the same TRP, or that the PDCCHs of PDSCHs scheduling the same TRPs are transmitted within the corresponding CORESETs.

[0402] In one example of search space beam / beam group configuration, a beam or beam group can be configured for each search space, and the TRP for each search space can be distinguished accordingly. For example, when the same beam / beam group or TCI state is configured in multiple search spaces, it can be assumed that the same TRP in the search space sends PDCCH, or that PDCCHs that schedule the same TRP in the search space send PDSCHs.

[0403] By distinguishing the CORESET or search space of each TRP as described above, the PDSCH and HARQ-ACK information of each TRP can be classified, and based on this, independent PUCCH resource usage and independent HARQ-ACK codebook generation for each TRP are possible.

[0404] The aforementioned configuration can be independent for each cell or each BWP. For example, although two different CORESETPoolIndex values ​​may be configured for the PCell, a CORESETPoolIndex value may not be configured for a specific SCell. In this case, it can be assumed that NC-JT transmission is configured for the PCell, but not for the SCells that do not have a configured CORESETPoolIndex value.

[0405] [Multi-TRP based on a single DCI]

[0406] According to another embodiment of this disclosure, the downlink beam for NC-JT transmission can be configured based on a single PDCCH.

[0407] In a single PDCCH-based NC-JT, PDSCHs sent by multiple TRPs can be scheduled via a single DCI. The number of TCI states can be used to indicate the number of TRPs sending the corresponding PDSCHs. That is, if the number of TCI states indicating the scheduling of PDSCHs in the DCI is two, it can be considered as a single PDCCH-based NC-JT transmission, and if the number of TCI states is one, it can be considered as a single TRP transmission. The TCI states indicated by the DCI can correspond to one or two TCI states activated by the MAC-CE. If the TCI states of the DCI correspond to two TCI states activated by the MAC-CE, a correspondence is established between the TCI code points indicated by the DCI and the TCI states activated by the MAC-CE, and there may be two TCI states activated by the MAC-CE that correspond to TCI code points.

[0408] The aforementioned configuration can be independent for each cell or each BWP. For example, a PCell may have up to two active TCI states corresponding to one TCI code point, while a specific SCell may have up to one active TCI state corresponding to one TCI code point. In this case, it can be assumed that NC-JT transmission is configured for the PCell, but not for the aforementioned SCell.

[0409] Referring to the above description regarding PDCCH and beam configuration, Rel-15 and Rel-16 NR currently do not support PDCCH retransmission, making it difficult to achieve the required reliability in scenarios requiring high reliability, such as URLLC. This disclosure provides a method for PDCCH retransmission via multiple transmission points (TRP), thereby improving the reliability of UE PDCCH reception. The specific method is described in detail in the following embodiments.

[0410] In the following description, for ease of description, cell, transmit point, panel, beam and / or transmit direction, etc., can be distinguished by upper-layer / L1 parameters such as TCI status or spatial relationship information, or by indicators such as cell ID, TRP ID, and panel ID, and are uniformly described as Transmit / Receive Point (TRP). Therefore, in practical applications, TRP can be appropriately replaced by one of the above terms.

[0411] In the following, in this disclosure, when determining whether cooperative communication is applied, the UE may use various methods, including assigning a PDSCH(s) to which cooperative communication is applied with a specific format, assigning a PDSCH(s) to which cooperative communication is applied with a specific indicator including whether cooperative communication is applied, assigning a PDSCH(s) to which cooperative communication is applied with a specific RNTI for scrambling, or assuming that cooperative communication is applied in a specific part indicated by the upper layer, etc. In the following, for ease of description, the case where the UE receives a PDSCH to which cooperative communication has been applied based on conditions similar to those described above will be referred to as the NC-JT case.

[0412] In the following description of this disclosure, upper-layer signaling may be signaling corresponding to at least one or a combination of one or more of the following signaling:

[0413] Master Information Block (MIB);

[0414] System Information Block (SIB) or SIB X (X=1, 2, ...);

[0415] Radio Resource Control (RRC); and / or

[0416] Media Access Control (MAC) Control Element (CE).

[0417] L1 signaling can be signaling corresponding to at least one signaling method, as described below, using a physical layer channel or a combination of one or more methods:

[0418] Physical Downlink Control Channel (PDCCH);

[0419] Downlink Control Information (DCI);

[0420] UE-specific DCI;

[0421] Group public DCI;

[0422] Public DCI;

[0423] Scheduling DCI (e.g., DCI used to schedule downlink or uplink data);

[0424] Non-scheduled DCI (e.g., DCI not used to schedule downlink or uplink data).

[0425] Physical Uplink Control Channel (PUCCH); and / or

[0426] Uplink Control Information (UCI).

[0427] In the following, in this disclosure, the determination of the priority between A and B may be referred to in various ways, such as selecting the one with higher priority to perform the corresponding operation according to a predetermined priority rule, or omitting or discarding the operation with lower priority.

[0428] In the following description of the foregoing examples, various embodiments will be provided. However, these embodiments are not independent embodiments, and one or more embodiments may be applied simultaneously or in combination. That is, the first to third embodiments described below may be implemented individually or by combining two or more of them.

[0429] <First Embodiment: PDCCH Repeat Transmission Method Based on Multiple TRPs>

[0430] As an embodiment of this disclosure, limitations on the maximum number of PDCCH candidate groups and CCEs will be described for a method of PDCCH retransmission considering multiple TRPs. For PDCCH retransmission considering multiple TRPs, various methods can exist depending on how each TCI state to be applied when transmitting the PDCCH in each TRP is applied to the various parameters described above for PDCCH transmission. For example, the various parameters for PDCCH transmission applying different TCI states may include CCEs, PDCCH candidate groups, control resource sets, search space, etc. During PDCCH retransmission considering multiple TRPs, soft combination schemes, selection schemes, etc., for combining multiple PDCCH signals received via repeated transmissions can be considered for the UE's reception scheme.

[0431] For repeated PDCCH transmissions via multiple TRPs, there are four possible methods, and for at least one of these four methods, the base station can perform configuration and indication for the UE via upper-layer signaling, via L1 signaling, or via a combination of upper-layer signaling and L1 signaling.

[0432] In one embodiment of [Method 1], a method is provided for repeatedly transmitting multiple PDCCHs having the same payload.

[0433] Method 1 is a method of repeatedly transmitting multiple control messages with the same DCI format and payload. The various segments of the aforementioned control messages may include information for scheduling the repeated transmission of PDSCHs, such as {PDSCH#1, PDSCH#2, ..., PDSCH#Y}, which are repeatedly transmitted on multiple time slots. The fact that the payloads of the repeatedly transmitted control messages are the same indicates that the PDSCH scheduling information of all control messages is the same. This PDSCH scheduling information includes, for example, the number of PDSCH retransmissions, time-domain PDSCH resource allocation information (i.e., TDRA), i.e., the time slot offset (K_0) between the control message and PDSCH#1, the number of PDSCH symbols, frequency-domain PDSCH resource allocation information (i.e., FDRA), DMRS port assignment information, PDSCH to HARQ acknowledgment timing, PUCCH resource indicators, etc. The UE can improve the reception reliability of control messages by soft-combining repeatedly transmitted control messages with the same payload.

[0434] For soft-associations, the UE needs to know in advance the resource location and the number of retransmissions of control information to be repeatedly transmitted. To this end, the base station can pre-indicate to the UE at least one of the time-domain, frequency-domain, and spatial-domain resource configurations for the aforementioned repeated transmission of control information. In the case of repeated transmission of control information in the time domain, the control information can be repeatedly transmitted on different CORESETs, on different search space sets within a CORESET, or on different PDCCH listening times within a CORESET and a search space set. The elements (CORESET elements, search space set elements, or PDCCHs) and locations (PDCCH candidate indices, etc.) of the resources repeatedly transmitted in the time domain can be indicated from the base station via upper-layer configuration, etc. The number of PDCCH retransmissions and / or the list and transmission mode of TRPs participating in the retransmission can be explicitly indicated, and upper-layer indication, MAC-CE / L1 signaling, etc., can be used as explicit indication methods. The list of TRPs can be indicated in the form of TCI states or the aforementioned QCL assumptions.

[0435] When control information is repeatedly transmitted in the frequency domain, it can be repeatedly transmitted on different cores, on different PDCCH candidates within a core, or for each CCE. The resource elements for repeatedly transmitting control information in the frequency domain and the locations of resources used for repeated transmission can be indicated from the base station via upper-layer configuration, etc. The number of repeated transmissions and / or the list and transmission mode of TRPs participating in the repeated transmissions can be explicitly indicated, and upper-layer indication, MAC-CE / L1 signaling, etc., can be used as explicit indication methods. The list of TRPs can be indicated in the form of TCI status or the aforementioned QCL assumption.

[0436] When repeatedly transmitting control information in the spatial domain, control information can be repeatedly transmitted through different CORESETs, or by configuring two or more TCI states in one CORESET.

[0437] In one embodiment of [Method 2], a method is provided for repeatedly transmitting multiple control messages that may have different DCI formats and / or payloads.

[0438] Method 2 is a method of repeatedly transmitting multiple control messages that may have different DCI formats and / or payloads. Multiple control messages are used to schedule the repeatedly transmitted PDSCHs, and the number of repeatedly transmitted PDSCHs indicated by each control message can be different from each other. For example, PDCCH#1 may indicate / include information for scheduling {PDSCH#1, PDSCH#2, ..., PDSCH#Y}, while PDCCH#2 may indicate / include information for scheduling {PDSCH#2, ..., PDSCH#Y}, and PDCCH#X may indicate / include information for scheduling {PDSCH Y}. Compared to Method 1 described above, this method of repeatedly transmitting control messages has the advantage of reducing the total delay time required for repeatedly transmitting control messages and PDSCHs. On the other hand, in Method 2, since the payloads of each repeatedly transmitted control message may be different from each other, soft combination of the repeatedly transmitted control messages is impossible, and therefore the reliability may be lower compared to Method 1 described above.

[0439] In Method 2, the UE may not need to know in advance the number of repeated transmissions, resource locations, etc., of the control information to be repeatedly transmitted, and the UE can independently decode and process each repeated transmission of control information. If the UE decodes multiple repeated transmissions of control information used to schedule the same PDSCH, it can process only the first repeated transmission of control information and ignore the second and subsequent repeated transmissions of control information. Alternatively, the number of repeated transmissions, resource locations, etc., of the control information to be repeatedly transmitted can be indicated in advance, and the indication method can be the same as that described in Method 1.

[0440] In one embodiment of [Method 3], a method is provided for separately and repeatedly transmitting multiple control messages that may have different DCI formats and / or payloads.

[0441] Method 3 involves separately and repeatedly transmitting multiple control messages that may have different DCI formats and / or payloads. In this case, each repeatedly transmitted control message can have the same DCI format and payload. The multiple control messages in Method 2 cannot be soft-combined, thus potentially resulting in lower reliability compared to Method 1, and the total latency required for repeated transmission of control messages and PDSCH in Method 1 may increase. Method 3 leverages the advantages of both Method 1 and Method 2, where control messages can be transmitted with high reliability compared to Method 2, while reducing the total latency required for repeated transmission of control messages and PDSCH compared to Method 1.

[0442] In method 3, to decode and soft-combine repeatedly transmitted control information, the soft combination of method 1 and the individual decoding of method 2 can be used. For example, during the repeated transmission of multiple control messages with different DCI formats and / or payloads, the control information transmitted the first time can be decoded as in method 2, and the repeated transmission of the decoded control information can be soft-combine as in method 1.

[0443] The base station can select and configure one of Method 1, Method 2, or Method 3 for the repeated transmission of control information. The base station can indicate the method for repeatedly transmitting control information to the UE via upper-layer signaling. Alternatively, the method for repeatedly transmitting control information can be indicated in conjunction with other configuration information. For example, the upper-layer configuration indicating the method for repeated PDSCH transmission can be combined with the indication for repeated transmission of control information. In the case of indicating repeated transmission of PDSCH according to the FDM scheme, this can be interpreted as repeating control information only via Method 1, because Method 2 does not reduce the delay time for repeated PDSCH transmission in the FDM scheme. For similar reasons, when indicating repeated transmission of PDSCH in the intra-slot TDM scheme, this can be interpreted as repeating control information according to Method 1. On the other hand, when indicating repeated transmission of PDSCH in the inter-slot TDM scheme, Method 1, Method 2, or Method 3 for repeating control information can be selected via upper-layer signaling or L1 signaling.

[0444] The base station can display a control information retransmission unit to the UE via upper-layer configuration, etc. Alternatively, the control information retransmission unit can be indicated in conjunction with other configuration information. For example, the upper-layer configuration indicating the PDSCH retransmission method can be combined with the control information retransmission unit. When indicating retransmission of PDSCH in an FDM scheme, this can be interpreted as retransmission of control information in either an FDM or SDM scheme. This is because retransmission of control information in a scheme such as inter-slot TDM does not reduce the delay caused by PDSCH retransmission in the FDM scheme. For similar reasons, when indicating retransmission of PDSCH in an intra-slot TDM scheme, this can be interpreted as retransmission of control information in an intra-slot TDM, FDM, or SDM scheme. On the other hand, when indicating retransmission of PDSCH in an inter-slot TDM scheme, the method of retransmitting control information can be selected via upper-layer signaling, etc., so that control information can be retransmitted in an inter-slot TDM, intra-slot TDM, FDM, or SDM scheme.

[0445] In one embodiment of [Method 4], a PDCCH transmission scheme applying multiple TCI states is provided.

[0446] In Method 4, to improve PDCCH reception performance without PDCCH retransmission, the PDCCH can be transmitted by applying different TCI states from multiple TRPs to different CCEs within the PDCCH candidate group. Method 4 does not correspond to PDCCH retransmission, but since it transmits the PDCCH in the corresponding TRP by applying different TCI states to different CCEs within the PDCCH candidate group, it can be a scheme for achieving spatial diversity within the PDCCH candidate group. The different CCEs applying different TCI states can be separated in the time or frequency dimension, and the UE needs to know in advance the location of the resources applying the different TCI states. The UE can receive different CCEs with different TCI states applied in different PDCCHs and can decode the CCEs independently or immediately.

[0447] <Second Embodiment: Limiting the Maximum Number of PDCCH Candidate Groups and CCEs Based on the PDCCH Repeat Transmission Method>

[0448] Regarding the methods supported in methods 1 to 4 for PDCCH retransmission at the base station, the UE can report UE capabilities to the base station individually. The UE can report UE capabilities to the base station, including whether the UE's reception scheme for PDCCH retransmission supports soft combination. The UE can report UE capabilities to the base station that limit the maximum number of PDCCH candidate groups and CCEs based on PDCCH retransmission. The reported UE capabilities may include at least one of the following: a limit per individual time slot, a limit per multiple time slots, a limit per individual span, and a limit per multiple spans. The UE can report UE capabilities to the base station that include a scheme for counting the number of PDCCH candidate groups and CCEs using methods supported in the PDCCH retransmission schemes of the four methods described above.

[0449] The schemes for counting PDCCH candidate groups and CCEs can differ depending on the UE capability report and the base station's transmission conditions.

[0450] Figure 17 This is a diagram illustrating the operation of a UE according to an embodiment of the present disclosure, which is used to count the number of PDCCH candidate groups and / or CCEs based on whether the base station's transmission conditions are met and the UE capability report for PDCCH retransmission.

[0451] refer to Figure 17 The UE reports its capabilities related to PDCCH retransmission to the base station (1701). Information regarding UE capabilities may include information about the PDCCH retransmission schemes supported by the UE (e.g., it could be one of [Method 1] to [Method 4]), whether it supports soft combinations based on PDCCH retransmission, the scheme for counting the number of PDCCH candidate groups and CCEs, the maximum number of PDCCH candidate groups and CCEs per individual time slot / multiple time slots and per individual span / multiple spans, and information about at least one of the aforementioned over-prescription schemes. As another embodiment, if information about UE capabilities is pre-configured for the corresponding UE, the operation in 1701 can be omitted. Furthermore, for UEs in a pre-prescribed group, if the information about UE capabilities is also applied as default information, operation 1701 can be omitted.

[0452] The UE can then receive first configuration information 1703 for PDCCH from the base station, and can also receive second configuration information 1704 for PDCCH retransmission. The first configuration information may include configuration information regarding at least one of the control area and search space. The second configuration information may include information assuming retransmission regarding at least one of the retransmission method, retransmission quantity, retransmission interval, retransmission period, PDCCH listening timing, and whether a connection between retransmissions can be identified. The UE may be able to receive at least a portion of the first and second configuration information via L1 signaling, or implicitly determine at least a portion of the first and second configuration information based on other configuration information. The first and second configuration information may be included in a single configuration information for provision. Therefore, the classification of the first and second configuration information illustrates an embodiment, and the method of providing the configuration information can be modified and implemented in various forms.

[0453] The UE that has received the configuration information determines the number of repeated transmissions (e.g., N). The UE determines whether the base station's transmission conditions are met (1707) if the number of repeated transmissions is greater than 1. The transmission conditions can be a combination of at least one of [Condition 1] to [Condition 4], which will be described later. If the transmission conditions are not met, the UE operates using the existing PDCCH candidate group number and CCE number counting scheme (second PDCCH candidate group number and / or CCE number counting scheme) (1711), and if the transmission conditions are met, the UE operates by applying a new standard (first PDCCH candidate group number and / or CCE number counting scheme) to the PDCCH candidate group number and CCE number counting (1709). When counting the number of PDCCH candidate groups and CCEs by applying the new standard, if the number of repeated PDCCH transmissions is N, the UE can apply one of the following [Operation 1] to [Operation 3]. If the number of repeated transmissions in operation 1705 is not greater than 1 (i.e., if the number of repeated transmissions is 1), the UE proceeds to operation 1711 and operates using the existing PDCCH candidate group number and CCE number counting scheme (the second PDCCH candidate group number and / or CCE number counting scheme). A repeated transmission count of 1 indicates that repeated transmissions are not performed.

[0454] [Operation 1] Count N repeated transmissions as 1.

[0455] Even if the UE receives N repeated PDCCH transmissions according to its UE capability, the number of PDCCH candidate groups and CCEs can be counted by treating all N repeated transmissions as 1. For example, when a repeated transmission is performed twice, the number of PDCCH candidate groups and / or CCEs can be counted by treating the two repeated PDCCHs as one.

[0456] [Operation 2] Existing counting scheme.

[0457] Regarding PDCCH candidates that are repeatedly transmitted N times, under the assumption, for example, that individual decoding is performed without soft combining, the UE can perform N counts of the number of PDCCH candidate groups and / or CCEs compared to before, based on the existing counting scheme. For example, when repeated transmission is performed twice, the two different PDCCH transmissions can be counted as 2, as in the case of counting the number of PDCCH candidate groups and / or CCEs.

[0458] [Operation 3] The count is 2 N -1.

[0459] Under the assumption that a count of 1 is used each time soft combination is performed on at least one combination of PDCCH candidates that are repeatedly transmitted N times, the UE can perform 2 when the repeated transmission is performed N times. N -1 count. For example, when two PDCCH duplicate transmissions are received from the base station, the UE can count the first PDCCH transmission and the second PDCCH transmission separately, and can additionally count by 1 by assuming a soft combination of the first PDCCH transmission and the second PDCCH transmission, thereby counting the number of PDCCH candidate groups and / or CCEs, making the total number 3 (2 2 -1 = 3 times).

[0460] It is possible to consider items as transmission conditions of the base station by combining at least one of the following [conditions 1] to [conditions 4], which makes it possible to count the number of PDCCH candidate groups and / or CCEs by applying the new standard as described above.

[0461] [Condition 1] Whether soft combination is supported.

[0462] The UE can count the number of PDCCH candidate groups and / or CCEs differently depending on whether it supports soft combination, which is transmitted to the base station via a UE capability report. For example, if the UE can support soft combination based on PDCCH retransmission, the UE can count the number of PDCCH candidate groups and / or CCEs by selecting one of the aforementioned operations 1 to 3. When the UE receives a PDCCH retransmission configuration or indication with soft combination enabled from the base station (e.g., based on the same DMRS location with the same scrambling sequence, the same PDCCH candidate group location based on the same hash function result, etc.), the UE can select one of operations 1 to 3 to count the number of PDCCH candidate groups and / or CCEs.

[0463] [Condition 2] Whether the repeatedly sent PDCCHs exist in the same control resource set or different control resource sets.

[0464] Depending on whether the PDCCHs repeatedly transmitted from the base station exist in the same control resource set or different control resource sets, the UE may count the number of PDCCH candidate groups and / or CCEs differently.

[0465] [Condition 3] PDCCH repeated transmission scheme.

[0466] The UE can count the number of PDCCH candidate groups and / or CCEs differently according to the four PDCCH retransmission schemes (methods 1 to 4) described above. When the base station configures and instructs the UE to perform soft-combining PDCCH retransmission schemes of methods 1 and 3, and when counting the number of PDCCH candidate groups and / or CCEs relative to the retransmission scheme of method 4 (i.e., the PDCCH transmission scheme considering multiple non-repeating TRPs), the UE can apply a new standard (a first PDCCH candidate group and CCE count scheme) to count the number of PDCCH candidate groups and / or CCEs.

[0467] [Condition 4] The number of TCI states applied, or whether the same TCI state or different TCI states are applied.

[0468] Depending on the number of TCI states applied to the PDCCH sent from the base station, or whether the same TCI state or different TCI states are applied, the UE may count the number of PDCCH candidate groups and / or CCEs differently.

[0469] <Third Embodiment: Oversubscription Method Based on PDCCH Repeat Transmission Method>

[0470] The scheme for counting the number of PDCCH candidate groups and / or CCEs can vary depending on the UE capability report and the base station's transmission conditions.

[0471] Figure 18 This is a diagram illustrating the operation of a UE, according to various embodiments of the present disclosure, to count the number of PDCCH candidate groups and / or CCEs based on whether the base station's transmission conditions are met and the UE capability report for PDCCH retransmission.

[0472] refer to Figure 18The UE reports its capabilities related to PDCCH retransmission to the base station in step 1801. Information regarding the reported UE capabilities may include information about the PDCCH retransmission schemes supported by the UE (e.g., it could be one of [Method 1] to [Method 4]), whether it supports soft combinations based on PDCCH retransmission, the scheme for counting the number of PDCCH candidate groups and CCEs, the maximum number of PDCCH candidate groups and CCEs per individual time slot / multiple time slots and per individual span / multiple spans, and information about at least one of the aforementioned over-prescription schemes. As another embodiment, if information about UE capabilities is pre-configured for the corresponding UE, the operation in step 1801 can be omitted. Furthermore, for UEs in a pre-prescribed group, if the information about UE capabilities is also applied as default information, operation 1801 can be omitted.

[0473] The UE can then receive first configuration information (1803) for PDCCH from the base station, and can also receive second configuration information (1805) for PDCCH retransmission. The first configuration information may include configuration information regarding at least one of the control area and search space. The second configuration information may include information regarding at least one of the retransmission method, retransmission quantity, retransmission interval, retransmission period, PDCCH listening timing assuming retransmission, and whether a connection between retransmissions can be identified. The UE can receive at least a portion of the first and second configuration information via L1 signaling, or implicitly determine at least a portion of the first and second configuration information based on other configuration information. The first and second configuration information may be included in a single configuration information for provision. Therefore, the classification of the first and second configuration information illustrates an embodiment, and the method of providing the configuration information can be modified and implemented in various forms.

[0474] The UE that has received the configuration information determines the number of 1807 retransmissions (e.g., N). If the number of repeated transmissions is greater than 1, the UE determines whether the base station's transmission condition is met (1809). The transmission condition can be a combination of at least one of the aforementioned [Condition 1] to [Condition 4]. If the transmission condition is not met, the UE performs operation 1813 using the existing over-subscription scheme (second over-subscription scheme), and if the transmission condition is met, the UE performs operation 1811 by applying a new standard (first over-subscription scheme) to the over-subscription scheme. When performing the over-subscription scheme by applying the new standard, if the number of repeated PDCCH transmissions is N, one of the following [Operation 4] and [Operation 5] can be applied. If the number of repeated transmissions in operation 1807 is not greater than 1 (i.e., if the number of repeated transmissions is 1), the UE proceeds to operation 1813 and operates using the existing over-subscription scheme (second over-subscription scheme). A number of repeated transmissions of 1 indicates that repeated transmissions are not performed.

[0475] [Operation 4] Reuse the existing overbooking scheme.

[0476] If, at a given time point, the number of PDCCH candidate groups and / or CCEs exceeds the maximum limit for the number of PDCCH candidate groups and / or CCEs, the UE can listen to only some configured search space sets, and the base station can transmit PDCCHs in the selected search space sets, thereby satisfying the maximum limit for the number of PDCCH candidate groups and CCEs. Even if PDCCH duplicate transmissions occur within a specific search space set or across multiple search space sets, the UE can still perform over-subscription in the existing manner. That is, among the search space sets existing at the given time point, search space sets whose search space type is configured as common search spaces can be selected with priority over search space sets configured as UE-specific search spaces. If all search space sets configured as common search spaces are selected (i.e., even after selecting all search spaces configured as common search spaces, if the maximum limit for the number of PDCCH candidate groups and CCEs is satisfied), the UE (or base station) can select a search space set configured as a UE-specific search space. If multiple search space sets are configured as UE-specific search spaces, the search space set with the lower search space set index can have a higher priority. Taking priority into account, a UE-specific search space set can be selected within the limits of the maximum number of PDCCH candidate groups and / or CCEs.

[0477] [Operation 5] Select some PDCCHs in the search space set.

[0478] If PDCCH retransmissions are performed within a specific search space set, when the UE considers PDCCH retransmissions to determine whether to select that search space set, if the search space set was not selected in the existing manner, the UE may select only some PDCCH retransmissions within the limits of the maximum number of PDCCH candidate groups and / or CCEs, and may not select the remaining PDCCH retransmissions. In this case, the criteria for selecting some PDCCH retransmissions may be to prioritize retransmissions that have already applied different TCI states, or to prioritize retransmissions performed in different control resource sets.

[0479] The item that can be considered as being able to implement the overbooking scheme by applying the new standard can be a combination of at least one of [Condition 1] to [Condition 4] in the second embodiment.

[0480] According to embodiments of this disclosure, as downlink control information is repeated, the maximum number of blind decoding attempts and the maximum number of CCEs that the UE can consider can be determined. As an example, the UE can receive different candidates for the downlink control channel using a soft-combining scheme, in which case the UE can bundle PDCCH candidates available for soft-combining and perform blind decoding with a count of 1. As another example, the UE can receive different PDCCH candidates for the downlink control channel using an optional decoding scheme, in which case if the UE is explicitly indicated with connection information regarding PDCCH candidates available for optional decoding, the UE can count 1 blind decoding time for the corresponding PDCCH candidate, and if the connection information for the PDCCH candidates available for optional decoding is implicitly indicated or unknown, the UE can count the number of individual blind decoding attempts for the corresponding PDCCH candidate. In addition to reception schemes such as soft-combining or optional decoding, embodiments of this disclosure can present limits and counting schemes on the maximum number of blind decoding attempts and the maximum number of CCEs in various ways, based on resource usage schemes for repeated transmission / reception, beam configurations for repeated transmission / reception, search space and control resource area configurations, aggregation levels, etc.

[0481] Figure 19 This is a diagram illustrating the structure of a UE in a wireless communication system according to an embodiment of the present disclosure.

[0482] refer to Figure 19The UE may include a transceiver, a memory (not shown), and a processor 1905, the transceiver including a receiver 1901 and a transmitter 1903. The processor 1905 may be at least one processor and may be referred to as a controller or control unit. The processor 1905 can control the entire device of the UE, causing the UE to operate according to each of the foregoing embodiments and combinations of at least one embodiment of this disclosure. However, the elements of the UE are not limited to the foregoing examples. For example, the UE may include more or fewer elements compared to the foregoing elements. Furthermore, the transceiver, memory, and processor may be implemented as at least one chip.

[0483] A transceiver can transmit signals to or receive signals from a base station. These signals may include control information and data. Therefore, a transceiver may include an RF transmitter configured to perform up-conversion and amplification of the transmitted signal's frequency, an RF receiver configured to perform low-noise amplification of the received signal and down-conversion of the received signal's frequency, etc. However, this is merely one embodiment of a transceiver, and the components of the transceiver are not limited to RF transmitters and RF receivers.

[0484] The transceiver can receive signals via a radio channel, output signals to the processor 1905, and transmit signals output from the processor 1905 via a radio channel.

[0485] The memory can store programs and data required for UE operation. The memory can store control information or data included in signals sent or received by the UE. The memory can include storage media or combinations of storage media, such as ROM, RAM, hard disk, CD-ROM, and DVD. Multiple memories may be present.

[0486] Processor 1905 can control a series of processes that allow the UE to operate according to each of the above embodiments and combinations of two or more embodiments. For example, processor 1905 can control the UE's operation of receiving PDCCH retransmissions by applying at least one of the aforementioned PDCCH retransmission method based on multiple TRPs, the limitation on the maximum number of PDCCH candidate groups and CCEs according to the PDCCH retransmission method, and the oversubscription method according to the PDCCH retransmission method. Multiple processors 1905 may be present, and processor 1905 can control multiple elements of the UE by executing programs stored in memory.

[0487] Figure 20 This is a diagram illustrating the structure of a base station in a wireless communication system according to an embodiment of the present disclosure.

[0488] refer to Figure 20The base station may include a transceiver, a memory (not shown), and a processor 2005, the transceiver including a receiver 2001 and a transmitter 2003. The base station may include a communication interface (not shown) for wired or wireless communication with another base station via a backhaul link. The processor 2005 may be at least one processor and may be referred to as a controller or control unit. The processor 2005 may control the entire device of the base station, causing the base station to operate according to each of the foregoing embodiments and a combination of at least one embodiment of this disclosure. However, the elements of the base station are not limited to the examples described above. For example, the base station may include more or fewer elements compared to the foregoing elements. Furthermore, the transceiver, memory, and processor may be implemented as at least one chip.

[0489] A transceiver can transmit signals to or receive signals from a UE. These signals may include control information and data. For this purpose, a transceiver may include an RF transmitter configured to perform up-conversion and amplification of the transmitted signal's frequency, an RF receiver configured to perform low-noise amplification of the received signal and down-conversion of the received signal's frequency, etc. However, this is merely one embodiment of a transceiver, and the components of the transceiver are not limited to RF transmitters and RF receivers.

[0490] The transceiver can receive signals via a radio channel, output signals to the processor 2005, and transmit signals output from the processor 2005 via a radio channel.

[0491] The memory can store programs and data required for base station operation. The memory can store control information or data included in signals transmitted or received by the base station. The memory can include storage media or combinations of storage media, such as ROM, RAM, hard disk, CD-ROM, and DVD. Multiple memories may be present.

[0492] Processor 2005 can control a series of processes that enable the base station to operate according to the foregoing embodiments of this disclosure. For example, processor 2005 can control each element of the base station to perform PDCCH retransmission by applying at least one of the foregoing PDCCH retransmission method based on multiple TRPs, limiting the maximum number of PDCCH candidate groups and CCEs according to the PDCCH retransmission method, and over-subscription method according to the PDCCH retransmission method. Multiple processors 2005 may be present, and each processor 2005 can control the elements of the base station by executing programs stored in memory.

[0493] The methods according to the various embodiments described in the claims or specification of this disclosure can be implemented in hardware, software, or a combination of hardware and software.

[0494] When these methods are implemented in software, a computer-readable storage medium may be provided for storing one or more programs (software modules). One or more programs stored in the computer-readable storage medium may be configured to be executed by one or more processors within an electronic device. The at least one program may include instructions causing the electronic device to perform methods according to the various embodiments of this disclosure as defined by the appended claims and / or disclosed herein.

[0495] The program (software module or software) can be stored in non-volatile memory, including random access memory and flash memory, read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), disk storage devices, optical disc-ROM (CD-ROM), digital versatile disc (DVD) or other types of optical storage devices, or magnetic tape. Alternatively, any combination of some or all of these can form the memory storing the program. Furthermore, an electronic device may include multiple such memories.

[0496] Furthermore, the program can be stored on an attachable storage device that can be accessed by the electronic device via a communication network such as the Internet, intranet, local area network (LAN), wide area network (WLAN), and storage area network (SAN), or a combination thereof. This storage device can access the electronic device via an external port. Additionally, a standalone storage device on the communication network can access portable electronic devices.

[0497] In the detailed embodiments described above, elements included in this disclosure are represented in a singular or plural form according to the presented embodiments. However, for the sake of convenience, singular or plural forms have been suitably chosen as presented, and this disclosure is not limited to elements expressed in a singular or plural form. Thus, an element represented in a plural form may also include a single element, or an element represented in a singular form may include multiple elements.

[0498] The embodiments of this disclosure described and illustrated in the specification and drawings have been presented to readily explain the technical content of this disclosure and to aid in understanding it, and are not intended to limit the scope of this disclosure. That is, it will be apparent to those skilled in the art that other modifications and changes can be made to it based on the technical concepts of this disclosure. Furthermore, the various embodiments described above can be combined as needed. For example, one embodiment of this disclosure can be partially combined with other embodiments to operate a base station and a UE. As an example, embodiments 1 and 2 of this disclosure can be combined with each other to operate a base station and a UE. Moreover, although the above embodiments have been described based on an FDD LTE system, other variations based on the technical concepts of the embodiments can also be implemented in other communication systems such as TDD LTE, 5G, or NR systems.

[0499] In the accompanying drawings describing the methods of this disclosure, the order of description does not always correspond to the order in which the steps of each method are performed, and the order of the steps may be changed or the steps may be performed in parallel.

[0500] Alternatively, in the accompanying drawings describing the methods of this disclosure, some elements may be omitted without departing from the basic spirit and scope of this disclosure, and only certain elements may be included.

[0501] Furthermore, in the methods of this disclosure, some or all of the elements of each embodiment may be combined without departing from the basic spirit and scope of this disclosure.

[0502] Although this disclosure has been described with reference to various embodiments, various changes and modifications will be apparent to those skilled in the art. This disclosure is intended to include such changes and modifications that fall within the scope of the appended claims.

Claims

1. A method performed by a user equipment (UE) in a wireless communication system, the method comprising: Sending first information related to physical downlink control channel (PDCCH) repetition to the base station, the first information including second information indicating the UE's ability to count two PDCCH candidates as three PDCCH candidates; Receive third information from the base station for controlling the resource set and fourth information for searching the space; and Listen for PDCCH candidates based on the second, third, and fourth information.

2. The method according to claim 1, wherein, UE capability is related to the number of blind decodings of two PDCCH candidates.

3. The method according to claim 1, wherein, Other candidates for monitoring PDCCH include: Listening to PDCCH candidates based on span, second information, third information, and fourth information. The span represents the number of consecutive symbols in the time slot in which the UE is configured to listen to the PDCCH.

4. The method according to claim 1, wherein, PDCCH repetition includes PDCCH repetition based on the multiple transmit / receive point (TRP).

5. A user equipment (UE) in a wireless communication system, the UE comprising: transceiver; as well as The processor is configured as follows: The transceiver sends first information related to the repetition of the Physical Downlink Control Channel (PDCCH) to the base station. The first information includes second information indicating the UE's ability to count two PDCCH candidates as three PDCCH candidates. The transceiver receives third information for controlling the resource set and fourth information for searching the space from the base station. and Listen for PDCCH candidates based on the second, third, and fourth information.

6. The UE according to claim 5, wherein, UE capability is related to the number of blind decodings of two PDCCH candidates.

7. The UE according to claim 5, wherein, The processor is also configured as follows: Listening to PDCCH candidates based on span, second information, third information, and fourth information. The span represents the number of consecutive symbols in the time slot in which the UE is configured to listen to the PDCCH.

8. The UE according to claim 5, wherein, PDCCH repetition includes PDCCH repetition based on the multiple transmit / receive point (TRP).

9. A method performed by a base station in a wireless communication system, the method comprising: The user equipment (UE) receives first information related to the repetition of the physical downlink control channel (PDCCH), the first information including second information indicating the UE's ability to count two PDCCH candidates as three PDCCH candidates; Send third information for controlling the resource set and fourth information for searching the space, and Downlink control information about PDCCH candidates is sent based on the second, third, and fourth information.

10. The method according to claim 9, wherein, UE capability is related to the number of blind decodings of two PDCCH candidates.

11. The method according to claim 9, wherein, Sending downlink control information also includes: Downlink control information about PDCCH candidates is sent based on span, second information, third information, and fourth information. The span represents the number of consecutive symbols in a time slot.

12. The method according to claim 9, wherein, PDCCH repetition includes PDCCH repetition based on the multiple transmit / receive point (TRP).

13. A base station in a wireless communication system, the base station comprising: transceiver; as well as The processor is configured as follows: The user equipment (UE) receives first information related to the repetition of the physical downlink control channel (PDCCH) via a transceiver. The first information includes second information indicating the UE's ability to count two PDCCH candidates as three PDCCH candidates. Send third information for controlling the resource set and fourth information for searching the space, and Based on the second, third, and fourth information, the transceiver sends downlink control information about the PDCCH candidate to the UE.

14. The base station according to claim 13, wherein, UE capability is related to the number of blind decodings of two PDCCH candidates.

15. The base station according to claim 13, wherein, The processor is also configured as follows: Based on the span, second information, third information, and fourth information, the transceiver sends downlink control information about the PDCCH candidate to the UE. The span represents the number of consecutive symbols in a time slot.

16. The base station according to claim 13, wherein, PDCCH repetition includes PDCCH repetition based on the multiple transmit / receive point (TRP).

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