Method and apparatus for downlink control channel reception and uplink control channel transmission in a wireless communication system - Patents.com

Abstract

A method and apparatus for receiving and transmitting signals / channels in a wireless communication system are provided. The method performed by a terminal includes receiving configuration information for a first search space (SS) set and a second SS set, where the first SS set having a first index includes a first PDCCH candidate having CCE AL 8 and a third PDCCH candidate having CCE AL 16, and the second SS set having a second index includes a second PDCCH candidate having CCE AL 8 and a fourth PDCCH candidate having CCE AL 16, receiving a PDCCH based on the configuration information, determining a PUCCH resource based on an index of a first CCE for the PDCCH, where if the first index of the first SS set is greater than the second index of the second SS set, the index of the first CCE is determined based on a CCE AL of a PDCCH candidate associated with the second SS set having the second index, and transmitting a PUCCH based on the determined PUCCH resource.

Description

[Technical field]

[0001] The present disclosure relates to the operation of a terminal (UE) and a base station (BS) in a wireless communication system. More specifically, the present disclosure relates to a method for receiving a downlink (DL) control channel by a terminal and a downlink shared channel based on the reception, and an apparatus capable of executing the method. The present disclosure also relates to a method for receiving a downlink control channel by a terminal and a transmission method for an uplink (UL) control channel based on the reception, and an apparatus capable of executing the method. [Background technology]

[0002] 5G mobile communication technology defines a wide frequency band to enable high transmission speeds and new services, and can be implemented in sub-6GHz bands such as 3.5 gigahertz (3.5GHz), as well as ultra-high frequency bands known as millimeter wave (mmWave) bands such as 28GHz and 39GHz (Above 6GHz). In addition, 6G mobile communication technology, known as the next system after 5G (Beyond 5G), is considering implementation in the terahertz band (for example, 95GHz to 3THz band) to achieve transmission speeds 50 times faster and ultra-low latency times reduced to one-tenth of those of 5G mobile communication technology.

[0003] In the early stage of 5G mobile communications technology, the following technologies will be developed to support services and satisfy performance requirements for enhanced Mobile BroadBand (eMBB), Ultra-Reliable Low-Latency Communications (URLLC), and massive Machine-Type Communications (mMTC): Beamforming and Massive MIMO to mitigate path loss and increase radio wave transmission distance in ultra-high frequency bands, various numerology support (multiple subcarrier spacing operation, etc.) and dynamic operation of slot formats for efficient use of ultra-high frequency resources, initial connection technology to support multiple beam transmission and wideband, definition and operation of Band-Width Part (BWP), new channel coding methods such as Low Density Parity Check (LDPC) code for large volume data transmission and Polar Code for highly reliable transmission of control information, L2 pre-processing, and Network Slicing to provide dedicated networks specialized for specific services. Standardization of the 3D slicing technology has been progressing.

[0004] Discussions are currently underway to improve and enhance the initial 5G mobile communications technology in consideration of the services that 5G mobile communications technology is intended to support. Physical layer standardization is underway for technologies such as Vehicle-to-Everything (V2X), which helps autonomous vehicles make driving decisions based on their own location and status information transmitted by the vehicle and increases user convenience, New Radio Unlicensed (NR-U), which aims to operate systems in unlicensed bands in accordance with various regulatory requirements, low power consumption technology for NR terminals (UE Power Saving), Non-Terrestrial Network (NTN), which is direct communication between terminals and satellites to ensure coverage in areas where communication with terrestrial networks is not possible, and positioning.

[0005] In addition, standardization is underway in the areas of radio interface architecture / protocol for technologies such as Industrial Internet of Things (IIoT) to support new services through linkage and integration with other industries, Integrated Access and Backhaul (IAB) to provide nodes for expanding network service areas by integrating wireless backhaul links and access links, mobility enhancement technologies including Conditional Handover and Dual Active Protocol Stack (DAPS) handover, and 2-step random access (2-step RACH for NR) to simplify random access procedures. Standardization is also underway in the areas of system architecture / service for 5G baseline architecture (e.g., Service based Architecture, Service based Interface) for the integration of Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) technologies, and Mobile Edge Computing (MEC) in which services are provided based on the location of the terminal.

[0006] When the 5G mobile communication system is commercialized, the number of connected devices, which is increasing explosively, will be connected to the communication network, and it is expected that the functions and performance of the 5G mobile communication system will need to be strengthened and the connected devices will need to be operated in an integrated manner.To this end, new research will be conducted on 5G performance improvement and complexity reduction using extended reality (XR) to efficiently support augmented reality (AR), virtual reality (VR), mixed reality (MR), artificial intelligence (AI) and machine learning (ML), AI service support, metabus service support, drone communication, etc.

[0007] In addition, the development of the 5G mobile communication system will be the basis for the development of multiple antenna transmission technologies such as new waveforms, full dimensional multiple input / output (FD-MIMO), array antennas, and large scale antennas to ensure coverage in the terahertz band of 6G mobile communication technology, high-dimensional spatial multiplexing technology using metamaterial-based lenses and antennas, orbital angular momentum (OAM), and reconfigurable intelligent surface (RIS) technology to improve the coverage of terahertz band signals, full duplex technology to improve the frequency efficiency and system network of 6G mobile communication technology, AI-based communication technology that utilizes satellites and artificial intelligence (AI) from the design stage and internalizes end-to-end AI support functions to optimize the system, and next-generation distributed computer technology that utilizes ultra-high performance communication and computing resources to realize services with a level of complexity that exceeds the limits of terminal computing capabilities.

[0008] The above information provided in this Background Information is intended to enhance the understanding of the present disclosure, and no determination or assertion has been made as to the applicability of any of the above as prior art in connection with the present disclosure. Summary of the Invention [Problem to be solved by the invention]

[0009] According to the embodiment, an apparatus and a method are provided that can effectively provide services in a mobile communication system.

[0010] Specifically, a method for receiving a downlink control channel in a terminal and receiving a downlink shared channel based on the reception, and an apparatus capable of executing the method are provided.

[0011] Also provided is a method for receiving a downlink control channel in a terminal and transmitting an uplink control channel based on the reception, and an apparatus capable of executing the method. [Means for solving the problem]

[0012] The present invention has been made to solve the problems and drawbacks mentioned above and to provide at least the advantages described below.

[0013] According to one aspect of the present disclosure, a method performed by a terminal in a wireless communication system includes a step of receiving configuration information for a first search space (SS) set and a second SS set, where the first SS set having a first index includes a first physical downlink control channel (PDCCH) candidate having a control channel element (CCE) aggregation level (AL) of 8 and a third PDCCH candidate having a CCE AL of 16, and the second SS set having a second index includes a second PDCCH candidate having a CCE AL of 8 and a fourth PDCCH candidate having a CCE AL of 16; receiving a PDCCH based on the configuration information; determining a physical uplink control channel (PUCCH) resource based on an index of a first CCE for the PDCCH, where if the first index of the first SS set is greater than the second index of the second SS set, the index of the first CCE is determined based on a CCE AL of a PDCCH candidate associated with the second SS set having the second index; and transmitting a PUCCH based on the determined PUCCH resource.

[0014] According to yet another aspect of the present disclosure, a method performed by a base station in a wireless communication system includes a step of transmitting configuration information for a first search space (SS) set and a second SS set to a terminal, where the first SS set having a first index includes a first PDCCH candidate having a CCE aggregation level (AL) of 8 and a third PDCCH candidate having a CCE AL of 16, and the second SS set having a second index includes a second PDCCH candidate having a CCE AL of 8 and a fourth PDCCH candidate having a CCE AL of 16; transmitting a PDCCH to the terminal based on the configuration information; and receiving a PUCCH from the terminal based on a PUCCH resource, where the PUCCH resource is identified based on an index of a first CCE for the PDCCH, and if the first index of the first SS set is greater than the second index of the second SS set, an index of the first CCE of the PDCCH is associated with a CCE AL of a PDCCH candidate associated with the second SS set having the second index.

[0015] According to yet another aspect of the present disclosure, a terminal in a wireless communication system includes a transceiver unit for transmitting and receiving signals, and a control unit coupled to the transceiver unit. The control unit is configured to receive configuration information for a first search space (SS) set and a second SS set via the transceiver unit, the first SS set having a first index including a first PDCCH candidate having a CCE aggregation level (AL) 8 and a third PDCCH candidate having a CCE AL 16, and the second SS set having a second index including a second PDCCH candidate having a CCE AL 8 and a fourth PDCCH candidate having a CCE AL 16, receive a PDCCH based on the configuration information via the transceiver unit, determine a PUCCH resource based on an index of a first CCE for the PDCCH, and if the first index of the first SS set is greater than the second index of the second SS set, the index of the first CCE is determined based on a CCE AL of a PDCCH candidate associated with the second SS set having the second index, and transmit a PUCCH based on the determined PUCCH resource via the transceiver unit.

[0016] According to yet another aspect of the present disclosure, in a wireless communication system, a base station includes a transceiver unit for transmitting and receiving signals, and a controller connected to the transceiver unit, and the controller transmits configuration information for a first search space (SS) set and a second SS set to a terminal, the first SS set having a first index includes a first PDCCH candidate having a CCE aggregation level (AL) of 8 and a third PDCCH candidate having a CCE AL of 16, and the second SS set having a second index includes a second PDCCH candidate having a CCE AL of 8 and a fourth PDCCH candidate having a CCE AL of 16, and is configured to transmit a PDCCH to the terminal based on the configuration information and receive a PUCCH from the terminal based on a PUCCH resource, the PUCCH resource being identified based on an index of a first CCE for the PDCCH, and if the first index of the first SS set is greater than the second index of the second SS set, an index of the first CCE of the PDCCH is associated with a CCE AL of a PDCCH candidate associated with the second SS set having the second index.

[0017] According to yet another aspect of the present disclosure, the method includes a step of a terminal receiving a configuration of multiple search spaces from a base station, a step of the terminal receiving a configuration of linked search spaces from the base station in which the same DCI is repeatedly transmitted among the multiple search spaces, a step of the terminal receiving DCI in the linked search spaces, a step of the terminal determining an aggregation level of a PDCCH for transmitting the received DCI based on configuration information of each search space of the linked search spaces, and a step of the terminal rate-matching and receiving a PDSCH based on the aggregation level determined in each search space.

[0018] According to yet another aspect of the present disclosure, the method includes a step of a terminal receiving a configuration of a plurality of search spaces from a base station, a step of the terminal receiving a configuration of a linked search space in which the same DCI is repeatedly transmitted among the plurality of search spaces from the base station, a step of the terminal receiving DCI for scheduling a PDSCH in the linked search space, a step of the terminal determining a search space that satisfies a specific condition based on configuration information of the linked search space, a step of the terminal determining an aggregation level in the search space that satisfies the specific condition, a step of the terminal determining an aggregation level in the search space that does not satisfy the specific condition based on the determined aggregation level, and a step of the terminal rate matching and receiving a PDSCH based on the aggregation level determined in the search space that satisfies the specific condition and the aggregation level determined in the search space that does not satisfy the specific condition.

[0019] According to yet another aspect of the present disclosure, the method includes a step of a terminal receiving a configuration of a plurality of search spaces from a base station, a step of the terminal receiving a configuration of a linked search space in which the same DCI is repeatedly transmitted among the plurality of search spaces from the base station, a step of the terminal receiving DCI for scheduling a PDSCH in the linked search space, a step of the terminal determining a search space that does not satisfy a specific condition based on configuration information of the linked search space, a step of the terminal determining an aggregation level in the search space that does not satisfy the specific condition, a step of the terminal determining an aggregation level in the search space that satisfies the specific condition based on the determined aggregation level, and a step of the terminal rate matching and receiving a PDSCH based on the aggregation level determined in the search space that does not satisfy the specific condition and the aggregation level determined in the search space that satisfies the specific condition.

[0020] The technical problems to be achieved in the embodiments of the present disclosure are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by a person having ordinary skill in the art to which the present disclosure pertains from the following description. Effect of the Invention

[0021] The disclosed embodiments may provide an apparatus and method capable of effectively providing services in a mobile communication system.

[0022] According to an embodiment of the present disclosure, resources to be used for PDCCH monitoring in a plurality of linked search spaces can be determined, and rate matching of PDSCH can be performed based on the determined resources.

[0023] Furthermore, according to one embodiment of the present disclosure, a PUCCH resource can be determined based on PDCCHs received in multiple linked search spaces, and a PUCCH including a HARQ-ACK can be transmitted based on the determined resource.

[0024] The effects obtained from the present disclosure are not limited to the effects described above, and other effects not mentioned here will be clearly understood from the following description by a person having ordinary skill in the art to which the present invention pertains. [Brief description of the drawings]

[0025] The above and other aspects, features, and advantages of particular embodiments of the present disclosure will become more apparent from the following description taken in conjunction with the accompanying drawings: [Figure 1] A diagram showing the basic structure of the time-frequency domain in a wireless communication system according to one embodiment of the present disclosure. [Diagram 2] A diagram showing a frame, subframe, and slot structure in a wireless communication system according to one embodiment of the present disclosure. [Diagram 3] 1 illustrates a bandwidth portion setting in a wireless communication system according to one embodiment of the present disclosure. [Figure 4] 1 illustrates a control region configuration for a downlink control channel in a wireless communication system according to an embodiment of the present disclosure. [Diagram 5] A diagram showing a structure of a downlink control channel in a wireless communication system according to one embodiment of the present disclosure. [Figure 6]A diagram for explaining a method in which a base station and a terminal transmit and receive data taking into account a downlink data channel and rate matching resources in a wireless communication system according to one embodiment of the present disclosure. [Figure 7] 1 is a diagram illustrating an example of frequency axis resource allocation of a PDSCH in a wireless communication system according to an embodiment of the present disclosure. [Figure 8] 1 is a diagram illustrating an example of time axis resource allocation of a PDSCH in a wireless communication system according to an embodiment of the present disclosure. [Figure 9] 1 is a diagram showing an example of time axis resource allocation based on subcarrier spacing of a data channel and a control channel in a wireless communication system according to an embodiment of the present disclosure. FIG. [Figure 10] A diagram showing a radio protocol structure of a base station and a terminal in single cell, carrier aggregation, and dual connectivity situations in a wireless communication system according to one embodiment of the present disclosure. [Figure 11] 1 illustrates an example of PDSCH rate matching taking into account repetitive PDCCH transmission according to one embodiment of the present disclosure. [Figure 12] 1 illustrates an example of a rate matching method for PDSCH when PDCCH candidates overlap with reserved resources according to an embodiment of the present disclosure. [Figure 13] 13 illustrates an example of a method for determining rate matching of a PDSCH depending on whether a PDCCH candidate for each search space is received or not, according to an embodiment of the present disclosure. [Figure 14A] FIG. 13 illustrates ambiguity in aggregation level determination according to one embodiment of the present disclosure. [Figure 14B] FIG. 13 illustrates ambiguity in aggregation level determination according to one embodiment of the present disclosure. [Figure 14C] FIG. 13 illustrates ambiguity in aggregation level determination according to one embodiment of the present disclosure. [Figure 14D] FIG. 13 illustrates ambiguity in aggregation level determination according to one embodiment of the present disclosure. [Figure 15A]A diagram illustrating rate matching for PDSCH in the case of aggregation level decision ambiguity according to one embodiment of the present disclosure. [Figure 15B] A diagram illustrating rate matching for PDSCH in the case of aggregation level decision ambiguity according to one embodiment of the present disclosure. [Figure 16] 1 shows an example illustrating a situation in which some of the PDCCH candidates are not monitored according to one embodiment of the present disclosure. [Figure 17] 1 illustrates an example of a rate matching method for a PDSCH taking into account PDCCH repetitive transmission, ambiguity in aggregation level decision, and reserved resources according to an embodiment of the present disclosure. [Figure 18] 1 illustrates an example of a rate matching method for a PDSCH taking into account PDCCH repetitive transmission, ambiguity in aggregation level decision, and reserved resources according to an embodiment of the present disclosure. [Figure 19] 1 illustrates an example of a rate matching method for a PDSCH taking into account PDCCH repetitive transmission, ambiguity in aggregation level decision, and reserved resources according to an embodiment of the present disclosure. [Figure 20] 1 illustrates an example of a rate matching method for a PDSCH taking into account PDCCH repetitive transmission, ambiguity in aggregation level decision, and reserved resources according to an embodiment of the present disclosure. [Figure 21] A diagram showing rate matching of PDSCH in the case of PDCCH repeated transmission and aggregation level decision ambiguity according to one embodiment of the present disclosure. [Figure 22] A diagram showing rate matching of PDSCH in the case of PDCCH repeated transmission and aggregation level decision ambiguity according to one embodiment of the present disclosure. [Figure 23A] A diagram showing rate matching of PDSCH in the case of PDCCH repeated transmission and aggregation level decision ambiguity according to one embodiment of the present disclosure. [Figure 23B] A diagram showing rate matching of PDSCH in the case of PDCCH repeated transmission and aggregation level decision ambiguity according to one embodiment of the present disclosure. [Figure 24] 1 is a flowchart of a rate matching method for a PDSCH according to an embodiment of the present disclosure. [Diagram 25] 1 is a flowchart of a rate matching method for a PDSCH according to an embodiment of the present disclosure. [Figure 26] 1 is a flowchart of a rate matching method for a PDSCH according to an embodiment of the present disclosure. [Figure 27] 1 illustrates an example of a method for determining a PUCCH resource according to an embodiment of the present disclosure. [Figure 28] 1 illustrates an example of a method for determining a PUCCH resource in the case of PDCCH repeated transmission and aggregation level decision ambiguity according to an embodiment of the present disclosure. [Figure 29] 13 is an example of a flowchart illustrating a terminal operation according to an embodiment of the present disclosure. [Diagram 30] FIG. 2 is a diagram illustrating the structure of a terminal in a wireless communication system according to an embodiment of the present disclosure. [Diagram 31] A diagram showing the structure of a base station in a wireless communication system according to one embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0027] In addition, technical contents that are well known in the technical field to which the present disclosure pertains and that are not directly related to the present disclosure will be omitted in order to more clearly convey the gist of the present disclosure without obscuring it.

[0028] For the same reason, in the accompanying drawings, some components are exaggerated, omitted, or illustrated in outline, and the size of each component does not entirely reflect the actual size. The same reference numerals are used to refer to the same or corresponding components in each drawing.

[0029] Various advantages and features of the present disclosure, and methods for achieving them, will become clear from the following detailed description of the embodiments together with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below, and may be embodied in various different forms. The embodiments are merely provided to complete the disclosure of the present disclosure and to fully inform those skilled in the art of the present disclosure of the scope of the disclosure, and the present disclosure is only defined by the scope of the claims.

[0030] Like numbers refer to like elements throughout the specification.

[0031] The terms described below are defined in consideration of the functions in this disclosure, and may vary depending on the intention or practice of a user or operator. Therefore, the definitions should be based on the contents of this specification as a whole.

[0032] Hereinafter, a base station is an entity that allocates resources to a terminal, and may be at least one of a gNode B, an eNode B, a Node B, a BS (Base Station), a radio access unit, a base station controller, or a node on a network. A terminal may include a UE (User Equipment), an MS (Mobile Station), a cellular phone, a smartphone, a computer, or a multimedia system that may have a communication function.

[0033] In the present disclosure, downlink (DL) refers to a radio transmission path of a signal transmitted from a base station to a terminal, and uplink (UL) refers to a radio transmission path of a signal transmitted from a terminal to a base station. In addition, although LTE (Long-Term Evolution) or LTE-A (LTE-advanced) systems may be described below as an example, the embodiments of the present disclosure may also be applied to other communication systems having similar technical backgrounds or channel forms. For example, this may include the fifth generation mobile communication technology (5G, new radio, NR) developed after LTE-A, and the following 5G may be a concept including existing LTE, LTE-A, and other similar services. In addition, the present disclosure may be applied to other communication systems with some modifications at the discretion of a person with skilled technical knowledge without significantly departing from the scope of the present disclosure.

[0034] In this case, each block of the flowchart and combinations of the flowcharts may be implemented by computer program instructions. These computer program instructions may be loaded onto a processor of a general purpose computer, a special purpose computer, or other programmable data processing equipment, such that the instructions executed by the processor of the computer or other programmable data processing equipment create means for performing the functions described in the blocks of the flowcharts. These computer program instructions may also be stored in a computer usable or computer readable memory that can direct the computer or other programmable data processing equipment to implement the functions in a particular manner, such that the instructions stored in the computer usable or computer readable memory can produce an article of manufacture that includes instruction means for performing the functions described in the blocks of the flowcharts. The computer program instructions may also be loaded onto a computer or other programmable data processing equipment, such that a series of operational steps are performed on the computer or other programmable data processing equipment to create a computer-implemented process, such that the instructions for the computer or other programmable data processing equipment provide steps for performing the functions described in the blocks of the flowcharts.

[0035] Also, each block may represent a module, segment, or portion of code that includes one or more executable instructions for performing a specified logical function. It should also be noted that in some alternative implementations, the functions noted in the blocks may occur out of order. For example, two blocks shown in succession may in fact be performed substantially simultaneously, or the blocks may often be performed in reverse order depending on the functionality involved.

[0036] In this embodiment, the term "module" refers to software or hardware components such as a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC), and the "module" plays either of these roles. However, the "module" is not limited to software or hardware. The "module" may be configured to be in an addressable storage medium or to execute one or more processors. Thus, by way of example, the "module" includes components such as software components, object-oriented software components, class components, and task components, as well as processes, functions, attributes, procedures, subroutines, program code segments, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The components and functions provided by the "module" may be combined into a smaller number of components and "modules" or may be further separated into additional components and "modules". Furthermore, the components and "modules" may be embodied to execute one or more central processing units (CPUs) in a device or a secure multimedia card. Additionally, in the embodiments, a "unit" may include one or more processors.

[0037] Wireless communication systems have evolved beyond providing early voice-centric services to broadband wireless communication systems providing high-speed, high-quality packet data services, such as communication standards such as 3GPP's High Speed ​​Packet Access (HSPA), Long Term Evolution (LTE or Evolved Universal Terrestrial Radio Access (E-UTRA)), LTE-A, LTE-Pro, 3GPP2's High Rate Packet Data (HRPD), Ultra Mobile Broadband (UMB), and IEEE's 802.16e.

[0038] As a representative example of the broadband wireless communication system, the LTE system adopts an Orthogonal Frequency Division Multiplexing (OFDM) scheme in the downlink (DL) and a Single Carrier Frequency Division Multiple Access (SC-FDMA) scheme in the uplink (UL). The uplink refers to a radio link through which a terminal (User Equipment (UE) or Mobile Station (MS)) transmits data or control signals to a base station (eNode B or base station (BS)), and the downlink refers to a radio link through which a base station transmits data or control signals to a terminal. The multiple access scheme generally allocates and operates time-frequency resources carrying data or control information for each user so as not to overlap with each other, i.e., to establish orthogonality, thereby making it possible to distinguish the data or control information of each user.

[0039] A communication system after LTE, i.e., a 5G communication system, must be able to freely reflect various requirements of users and service providers, and must support services that simultaneously meet various requirements. Services considered for the 5G communication system include enhanced Mobile Broadband (eMBB), massive Machine Type Communication (mMTC), Ultra Reliability Low Latency Communication (URLLC), etc.

[0040] eMBB aims to provide a data transmission rate that is higher than the data transmission rate supported by existing LTE, LTE-A, or LTE-Pro. For example, in a 5G communication system, eMBB must be able to provide a maximum transmission rate of 20 Gbps in the downlink and a maximum transmission rate of 10 Gbps in the uplink from the perspective of one base station. In addition, the 5G communication system must provide an increased user perceived data rate while providing the maximum transmission rate. In order to meet these requirements, various improvements in transmission and reception technologies are required, including improved multiple antenna (Multi Input Multi Output, MIMO) transmission technology. In addition, while LTE transmits signals using a maximum transmission bandwidth of 20 MHz in the 2 GHz band, the 5G communication system can meet the data transmission rate required by the 5G communication system by using a frequency bandwidth wider than 20 MHz in the 3 to 6 GHz or 6 GHz or higher frequency band.

[0041] At the same time, mMTC is being considered to support application services such as the Internet of Things (IoT) in 5G communication systems. In order to efficiently provide the Internet of Things, mMTC is required to support the connection of a large number of terminals within a cell, improve terminal coverage, improve battery life, and reduce terminal costs. The Internet of Things provides communication functions in conjunction with various sensors and various devices, so it is necessary to support a large number of terminals (e.g., 1,000,000 terminals / km) within a cell. 2 ) must be supported. In addition, because terminals that support mMTC are likely to be located in shadow areas where cells cannot cover, such as underground areas of buildings, due to the characteristics of the service, they may require wider coverage than other services provided by 5G communication systems. Terminals that support mMTC must be low-cost terminals, and because it is difficult to frequently replace the terminal battery, they may require a very long battery life time, such as 10 to 15 years.

[0042] Finally, URLLC is a cellular-based wireless communication service used for mission-critical purposes. For example, services used for remote control of robots or machinery, industrial automation, unmanned aerial vehicles, remote health care, emergency alerts, etc. can be considered. Therefore, the communication provided by URLLC must provide very low latency and very high reliability. For example, a service supporting URLLC must meet air interface latency of less than 0.5 milliseconds and at the same time, it must meet the following requirements: -5 The following packet error rate requirements are required. Therefore, for services that support URLLC, the 5G system must provide a smaller transmit time interval (TTI) than other services, and at the same time, design requirements may be required to allocate wider resources in the frequency band to ensure the reliability of the communication link.

[0043] The three 5G services, i.e., eMBB, URLLC, and mMTC, may be multiplexed and transmitted in one system. In this case, different transmission / reception techniques and transmission / reception parameters may be used between the services to meet different requirements of each service. Of course, 5G is not limited to the above three services.

[0044] [NR time-frequency resources]

[0045] FIG. 1 is a diagram showing a basic structure of a time-frequency domain in a wireless communication system according to an embodiment of the present disclosure.

[0046] Referring to FIG. 1, the horizontal axis represents the time domain, and the vertical axis represents the frequency domain. In the time and frequency domains, the basic unit of a resource is a resource element (RE, 101), which may be defined as one OFDM (Orthogonal Frequency Division Multiplexing) symbol 102 on the time axis and one subcarrier 103 on the frequency axis. In the frequency domain,

number

[0047] FIG. 2 is a diagram showing a frame, subframe, and slot structure in a wireless communication system according to an embodiment of the present disclosure.

[0048] Referring to FIG. 2, a frame (Frame, 200), a subframe (Subframe, 201), and a slot (Slot, 202) are shown. One frame 200 may be defined as 10 ms. One subframe 201 may be defined as 1 ms, and therefore one frame 200 may be composed of a total of 10 subframes 201. One slot 202, 203 may be defined as 14 OFDM symbols (i.e., the number of symbols per slot (

number

[0049] In the example of FIG. 2, the subcarrier spacing setting value μ=0 (204) and μ=1 (205) are shown. When μ=0 (204), one subframe 201 may be composed of one slot 202, and when μ=1 (205), one subframe 201 may be composed of two slots 203. That is, the number of slots per subframe (

number

number

number

[0050] [Table 1]

[0051] Bandwidth Part (BWP)

[0052] FIG. 3 is a diagram illustrating bandwidth portion setting in a wireless communication system according to one embodiment of the present disclosure.

[0053] 3, an example is shown in which a terminal bandwidth (UE bandwidth) 300 is set to two bandwidth parts, i.e., a bandwidth part #1 (BWP#1) 301 and a bandwidth part #2 (BWP#2) 302. The base station may set one or more bandwidth parts to the terminal, and information such as that shown in Table 2 below can be set for each bandwidth part.

[0054] [Table 2]

[0055] Of course, the above examples are not limiting, and in addition to the above configuration information, various parameters related to the bandwidth portion may be configured in the terminal. These information may be transmitted from the base station to the terminal by higher layer signaling, for example, Radio Resource Control (RRC) signaling. At least one of the configured one or more bandwidth portions may be activated. Whether or not the configured bandwidth portion is activated may be semi-statically transmitted from the base station to the terminal by RRC signaling, or dynamically transmitted by Downlink Control Information (DCI).

[0056] According to some embodiments, an initial bandwidth portion (Initial BWP) for an initial connection may be set by a base station in a master information block (MIB) for a terminal before a radio resource control (RRC) connection. More specifically, the terminal may receive configuration information for a control region (Control Resource Set, CORESET) and a search space (Search Space) in which a PDCCH for receiving system information (which may correspond to Remaining System Information; RMSI or System Information Block 1; SIB1) required for an initial connection may be transmitted, using the MIB in the initial connection stage. The control region and search space set in the MIB may each be regarded as an identity (ID) 0. The base station may notify the terminal of configuration information such as frequency allocation information, time allocation information, and numerology for the control region #0, using the MIB. In addition, the base station may notify the terminal of configuration information for a monitoring period and occasion for the control region #0, i.e., configuration information for the search space #0, using the MIB. The terminal may regard the frequency domain set as control domain #0 acquired from the MIB as the initial bandwidth portion for the initial connection. In this case, the identifier (ID) of the initial bandwidth portion may be regarded as 0.

[0057] The settings for the bandwidth portion supported by 5G may be used for various purposes.

[0058] When the bandwidth supported by the terminal is smaller than the system bandwidth, it can be supported by the bandwidth portion configuration. For example, the base station configures the frequency location of the bandwidth portion (configuration information 2) to the terminal, so that the terminal can transmit and receive data at a specific frequency location within the system bandwidth.

[0059] In order to support different numerologies, a base station can set multiple bandwidth parts to a terminal. For example, to support data transmission and reception using a subcarrier interval of 15 kHz and a subcarrier interval of 30 kHz in a certain terminal, two bandwidth parts can be set with subcarrier intervals of 15 kHz and 30 kHz, respectively. The different bandwidth parts may be frequency division multiplexed, and when data is to be transmitted and received at a specific subcarrier interval, the bandwidth part set with the corresponding subcarrier interval may be activated.

[0060] Also, according to some embodiments, in order to reduce the power consumption of the terminal, the base station may set bandwidth portions having different bandwidth sizes to the terminal. For example, if the terminal supports a very large bandwidth, for example, a bandwidth of 100 MHz, and constantly transmits and receives data in the bandwidth, very large power consumption may occur. In particular, monitoring unnecessary downlink control channels in a large bandwidth of 100 MHz in a situation where there is no traffic may be very inefficient in terms of power consumption. In order to reduce the power consumption of the terminal, the base station may set a bandwidth portion of a relatively small bandwidth, for example, a bandwidth portion of 20 MHz, to the terminal. In a situation where there is no traffic, the terminal may perform a monitoring operation in the 20 MHz bandwidth portion, and when data is generated, it may transmit and receive data in the 100 MHz bandwidth portion according to the instruction of the base station.

[0061] In the method for setting the bandwidth part, a terminal before RRC connection may receive setting information for an initial bandwidth part from a master information block (MIB) in an initial connection stage. More specifically, the terminal may receive a control region (Control Resource Set, CORESET) for a downlink control channel in which downlink control information (DCI) for scheduling a system information block (SIB) may be transmitted from an MIB of a physical broadcast channel (PBCH). The bandwidth of the control region in which the MIB is set may be regarded as an initial bandwidth part, and the terminal may receive a physical downlink shared channel (PDSCH) in which a SIB is transmitted in the set initial bandwidth part. In addition to receiving the SIB, the initial bandwidth part may be used for other system information (OSI), paging, and random access.

[0062] [Bandwidth portion (BWP) change]

[0063] When one or more bandwidth parts are configured for a terminal, the base station can instruct the terminal to change (or switch, transition) to the bandwidth part using a bandwidth part indicator field in the DCI. As an example, in FIG. 3, when the currently activated bandwidth part of the terminal is bandwidth part # (1301), the base station can instruct the terminal to use the bandwidth part indicator in the DCI to use bandwidth part #2 (302), and the terminal can change the bandwidth part to bandwidth part #2 (302) indicated by the bandwidth part indicator in the received DCI.

[0064] As described above, the DCI-based bandwidth portion change may be indicated by the DCI that schedules the PDSCH or PUSCH. Therefore, when the terminal receives a bandwidth portion change request, the terminal must be able to smoothly receive or transmit the PDSCH or PUSCH scheduled by the DCI in the changed bandwidth portion. For this purpose, the standard specifies a delay time (T BWP ) and may be defined, for example, as shown in Table 3.

[0065] [Table 3]

[0066] The requirement for the bandwidth portion change delay time supports Type 1 or Type 2 depending on the capability of the terminal. The terminal can report the bandwidth portion delay time type that it can support to the base station.

[0067] According to the bandwidth portion change delay time requirement mentioned above, if a terminal receives a DCI containing a bandwidth portion change indicator in slot n, the terminal shall change to the new bandwidth portion indicated by the bandwidth portion change indicator in slot n+T. BWP The base station can complete the process at a time not later than the bandwidth change delay time (T BWP ) to determine the time domain resource allocation for the data channel. That is, when the base station schedules the data channel to a new bandwidth portion, the base station can schedule the data channel to a time after the bandwidth portion change delay time in the method of determining the time domain resource allocation for the data channel. In this way, the terminal can determine whether the DCI instructing the bandwidth portion change is to be after the bandwidth portion change delay time (T BWP ) the slot offset (K0 or K2) value.

[0068] If the terminal receives a DCI (e.g., DCI format 1_1 or 0_1) indicating a bandwidth portion change, the terminal does not need to perform any transmission or reception in a time interval corresponding to from the third symbol of a slot in which a PDCCH including the DCI is received to the start of a slot indicated as a slot offset (K0 or K2) value indicated in a time domain resource allocation indicator field in the DCI. For example, if the terminal receives a DCI indicating a bandwidth portion change in slot n and the slot offset value indicated in the DCI is K, the terminal does not need to perform any transmission or reception from the third symbol of slot n to the previous symbol of slot n+K (i.e., the last symbol of slot n+K-1).

[0069] [SS / PBCH block]

[0070] The SS / PBCH block may refer to a physical layer channel block consisting of a PSS (Primary SS), an SSS (Secondary SS), and a PBCH.

[0071] - PSS: A signal that is a reference for downlink time / frequency synchronization and provides part of the cell ID information.

[0072] - SSS: It serves as a reference for downlink time / frequency synchronization and provides remaining cell ID information that is not provided by PSS. It can also serve as a reference signal for demodulation of PBCH.

[0073] -PBCH: Provides system information required for transmission and reception of data channels and control channels of a terminal. The system information may include search space-related control information indicating radio resource mapping information of a control channel, scheduling control information for a separate data channel that transmits system information, etc.

[0074] - SS / PBCH block: The SS / PBCH block is a combination of PSS, SSS, and PBCH. One or more SS / PBCH blocks may be transmitted within a 5 ms period, and each transmitted SS / PBCH block may be distinguished by an index.

[0075] The terminal can detect the PSS and SSS in the initial access stage and can decode the PBCH. The terminal can obtain the MIB from the PBCH and can receive the setting of the control area (Control Resource Set; CORESET) #0 (which may correspond to the control area with the control area index of 0) from the MIB. The terminal can monitor the control area #0 assuming that the selected SS / PBCH block and the demodulation reference signal (DMRS) transmitted in the control area #0 are QCL (quasi co-located). The terminal can receive system information from the downlink control information transmitted in the control area #0. The terminal can obtain the setting information related to the random access channel (RACH) required for the initial access from the received system information. The terminal can transmit a physical RACH (PRACH) to the base station considering the selected SS / PBCH index, and the base station receiving the PRACH can obtain information regarding the SS / PBCH block index selected by the terminal. The base station can know which block the terminal selected from each SS / PBCH block and the fact that it is monitoring the control area #0 associated with the selected block.

[0076] [PDCCH:DCI related]

[0077] In a 5G system, scheduling information for uplink data (or a Physical Uplink Shared Channel (PUSCH)) or downlink data (or a Physical Downlink Shared Channel (PDSCH)) is transmitted from a base station to a terminal by DCI. The terminal can monitor a fallback DCI format and a non-fallback DCI format for the PUSCH or PDSCH. The fallback DCI format may include fixed fields predefined between the base station and the terminal, and the non-fallback DCI format may include configurable fields.

[0078] The DCI may be transmitted on a physical downlink control channel (PDCCH) after undergoing channel coding and modulation processes. A cyclic redundancy check (CRC) may be added to the DCI message payload, and the CRC may be scrambled with a radio network temporary identifier (RNTI) corresponding to the identity of the terminal. Different RNTIs may be used depending on the purpose of the DCI message, for example, UE-specific data transmission, power control command, or random access response. That is, the RNTI is not explicitly transmitted, but is included in the CRC calculation process and transmitted. Upon receiving a DCI message transmitted on the PDCCH, the terminal checks the CRC using the assigned RNTI, and if the CRC check result is correct, the terminal knows that the message was transmitted to the terminal.

[0079] For example, DCI for scheduling a PDSCH for system information (SI) may be scrambled with SI-RNTI. DCI for scheduling a PDSCH for a Random Access Response (RAR) message may be scrambled with RA-RNTI. DCI for scheduling a PDSCH for a paging message may be scrambled with P-RNTI. DCI for notifying a Slot Format Indicator (SFI) may be scrambled with SFI-RNTI. DCI for notifying a Transmit Power Control (TPC) may be scrambled with TPC-RNTI. DCI for scheduling a terminal-specific PDSCH or PUSCH may be scrambled with a Cell RNTI (C-RNTI).

[0080] DCI format 0_0 may be used for a countermeasure DCI for scheduling a PUSCH, and in this case, the CRC may be scrambled with the C-RNTI. DCI format 0_0 with the CRC scrambled with the C-RNTI may include, for example, the information in Table 4.

[0081] [Table 4]

[0082] DCI format 0_1 ​​may be used for non-target DCI that schedules PUSCH, and in this case, the CRC may be scrambled with the C-RNTI. DCI format 0_1 ​​with the CRC scrambled with the C-RNTI may include, for example, the information in Table 5.

[0083] [Table 5A] [Table 5B]

[0084] DCI format 1_0 may be used for a countermeasure DCI for scheduling a PDSCH, and in this case, the CRC may be scrambled with the C-RNTI. DCI format 1_0 with the CRC scrambled with the C-RNTI may include, for example, the information in Table 6.

[0085] [Table 6]

[0086] DCI format 1_1 may be used for non-target DCI that schedules PDSCH, and in this case, the CRC may be scrambled with the C-RNTI. DCI format 1_1 with the CRC scrambled with the C-RNTI may include, for example, the information in Table 7.

[0087] [Table 7]

[0088] [PDCCH:CORESET, REG, CCE, Search Space]

[0089] 4 shows a configuration of a control region of a downlink control channel in a wireless communication system according to an embodiment of the present disclosure. That is, FIG. 4 shows an example of a control region (Control Resource Set, CORESET) in which a downlink control channel is transmitted in a 5G wireless communication system.

[0090] 4, two control regions (control region #1 401 and control region #2 402) are set in a UE bandwidth part 410 on the frequency axis and in one slot 420 on the time axis. The control regions 401 and 402 may be set to a specific frequency resource 403 in the entire UE bandwidth part 410 on the frequency axis. On the time axis, one or more OFDM symbols may be set, which may be defined as a control region length (Control Resource Set Duration, 404).

[0091] Control region #1 401 is set to have a control region length of two symbols, and control region #2 402 is set to have a control region length of one symbol.

[0092] In the above-mentioned 5G, the control region may be set by the base station to the terminal through higher layer signaling (e.g., system information, MIB (Master Information Block), RRC (Radio Resource Control) signaling). Setting the control region to the terminal means providing information such as a control region identity, a frequency position of the control region, and a symbol length of the control region. For example, the information in Table 8 may be included.

[0093] [Table 8]

[0094] In Table 8, the tci-StatesPDCCH (abbreviated as TCI (Transmission Configuration Indication) state) configuration information may include information on one or more SS (Synchronization Signal) / PBCH (Physical Broadcast Channel) block indexes or CSI-RS (Channel State Information Reference Signal) indexes that are in a QCL (Quasi Co Located) relationship with the DMRS transmitted in the corresponding control region.

[0095] 5 illustrates a downlink control channel in a wireless communication system according to an embodiment of the present disclosure. More specifically, FIG. 5 illustrates an example of a basic unit of time and frequency resources constituting a downlink control channel available in 5G.

[0096] 5, a basic unit of time and frequency resources constituting a control channel may be a Resource Element Group (REG, 503), and the REG 503 may be defined as one OFDM symbol 501 on the time axis and one Physical Resource Block (PRB, 502) on the frequency axis, i.e., 12 subcarriers. The base station may configure a downlink control channel allocation unit by concatenating the REGs 503.

[0097] As shown in FIG. 5, if the basic unit to which a downlink control channel is allocated in 5G is a CCE (Control Channel Element, 504), one CCE 504 may be composed of a plurality of REGs 503. For example, a REG 503 may be composed of 12 REs, and if one CCE 504 is composed of six REGs 503, one CCE 504 may be composed of 72 REs. When a downlink control region is set, the region may be composed of a plurality of CCEs 504, and a specific downlink control channel may be mapped to one or a plurality of CCEs 504 according to an aggregation level (AL) in the control region and transmitted. The CCEs 504 in the control region are divided by numbers, and the numbers of the CCEs 504 may be given by a logical mapping method.

[0098] The basic unit of the downlink control channel shown in FIG. 5, i.e., REG 503, may include all of the RE to which DCI is mapped and the area to which DMRS 505, which is a reference signal for decoding the RE, is mapped. Three DMRSs 505 may be transmitted in one REG 503. The number of CCEs required to transmit the PDCCH may be 1, 2, 4, 8, or 16 depending on an aggregation level (AL), and different numbers of CCEs may be used to implement link adaptation of the downlink control channel. For example, when AL=L, one downlink control channel may be transmitted by L CCEs. A terminal must detect a signal without knowing information about the downlink control channel, and a search space representing a set of CCEs is defined for blind decoding. A search space is a set of downlink control channel candidates consisting of CCEs that a terminal should attempt to decode at a given aggregation level, and since there are various aggregation levels that create one CCE set with 1, 2, 4, 8, and 16 CCEs, a terminal may have multiple search spaces. A search space set may be defined as a set of search spaces at all configured aggregation levels.

[0099] The search space may be classified into a common search space and a UE-specific search space. A certain group of terminals or all terminals may search the common search space of the PDCCH to receive cell-common control information such as dynamic scheduling for system information and paging messages. For example, PDSCH scheduling assignment information for transmitting SIBs including cell operator information may be received by searching the common search space of the PDCCH. In the case of the common search space, a certain group of terminals or all terminals must receive the PDCCH, and it may be defined as a set of CCEs that have already been committed. Scheduling assignment information for a UE-specific PDSCH or PUSCH may be received by searching the UE-specific search space of the PDCCH. The UE-specific search space may be UE-specifically defined as a function of the identity of the terminal and various system parameters.

[0100] In 5G, parameters for the search space for the PDCCH may be configured in the terminal from the base station via higher layer signaling (e.g., SIB, MIB, RRC signaling).

[0101] For example, the base station may configure the number of PDCCH candidate groups at each aggregation level L, the monitoring period for the search space, the monitoring occasion for the search space in units of symbols in a slot, the search space type (common search space or terminal-specific search space), the combination of the DCI format and RNTI to be monitored in the search space, the control region index to be monitored in the search space, etc., to the terminal. For example, the information in Table 9 may be included.

[0102] [Table 9A] [Table 9B]

[0103] The configuration information allows the base station to configure one or more search space sets for the terminal. According to some embodiments, the base station can configure the terminal with search space set 1 and search space set 2, and can configure the terminal to monitor DCI format A scrambled with X-RNTI in the common search space in search space set 1, and to monitor DCI format B scrambled with Y-RNTI in the terminal-specific search space in search space set 2.

[0104] According to the configuration information, there may be one or more search space sets in the common search space or the terminal-specific search space. For example, the search space set #1 and the search space set #2 may be set as the common search space, and the search space set #3 and the search space set #4 may be set as the terminal-specific search space.

[0105] The following DCI format and RNTI combinations may be monitored in the common search space. Of course, the following examples are not limited to these.

[0106] - DCI format 0_0 / 1_0 with CRC scrambled by C-RNTI, CS-RNTI, SP-CSI-RNTI, RA-RNTI, TC-RNTI, P-RNTI, SI-RNTI

[0107] - DCI format 2_0 with CRC scrambled by SFI-RNTI

[0108] - DCI format 2_1 with CRC scrambled by INT-RNTI

[0109] - DCI format 2_2 with CRC scrambled by TPC-PUSCH-RNTI, TPC-PUCCH-RNTI

[0110] - DCI format 2_3 with CRC scrambled by TPC-SRS-RNTI

[0111] In the terminal-specific search space, the following combinations of DCI format and RNTI may be monitored. Of course, the following examples are not limited to these.

[0112] - DCI format 0_0 / 1_0 with CRC scrambled by C-RNTI, CS-RNTI, TC-RNTI

[0113] - DCI format 1_0 / 1_1 with CRC scrambled by C-RNTI, CS-RNTI, TC-RNTI

[0114] The specified RNTI shall comply with the following definition and usage:

[0115] C-RNTI (Cell RNTI): Used for terminal-specific PDSCH scheduling

[0116] TC-RNTI (Temporary Cell RNTI): Used for terminal-specific PDSCH scheduling

[0117] CS-RNTI (Configured Scheduling RNTI): Semi-statically configured UE-specific PDSCH scheduling

[0118] RA-RNTI (Random Access RNTI): Used for PDSCH scheduling in the random access phase

[0119] P-RNTI (Paging RNTI): PDSCH scheduling use when paging is transmitted

[0120] SI-RNTI (System Information RNTI): System information is transmitted for PDSCH scheduling

[0121] INT-RNTI (Interruption RNTI): Used to indicate whether puncturing is performed for the PDSCH.

[0122] TPC-PUSCH-RNTI (Transmit Power Control for PUSCH RNTI): Use for indicating power adjustment command for PUSCH

[0123] TPC-PUCCH-RNTI (Transmit Power Control for PUCCH RNTI): Use of power adjustment command indication for PUCCH

[0124] TPC-SRS-RNTI (Transmit Power Control for SRS RNTI): Use of power adjustment command indication for SRS

[0125] The DCI format specified above may follow the definition as in the example of Table 10.

[0126] [Table 10]

[0127] In 5G, a search space of a control domain p, a search space set s, and an aggregation level L may be expressed as follows in Equation 1:

[0128] [Formula 1]

[0129]

number

[0130] - L: Assembled level

[0131] -n CI : Carrier index

[0132] - N CCE,p : The total number of CCEs in the control region p

[0133]

number

[0134]

number

[0135]

number

[0136] - i=0,…,L-1

[0137]

number

[0138] -n RNTI :Device identifier

[0139]

number

[0140]

number

[0141] In 5G, multiple search space sets can be set with different parameters (e.g., parameters in Table 9), so that the set of search space sets monitored by the terminal at each time point may change. For example, if search space set #1 is set to an X-slot period and search space set #2 is set to a Y-slot period, and X and Y are different, the terminal can monitor both search space set #1 and search space set #2 in a specific slot, and can monitor one of search space set #1 and search space set #2 in a specific slot.

[0142] [PDCCH:BD / CCE limit]

[0143] When multiple search space sets are configured for a terminal, the following conditions may be taken into consideration in determining which search space set the terminal should monitor.

[0144] If the terminal receives the setting of r15monitoringcapability as the value of monitoringCapabilityConfig-r16, which is higher layer signaling, the terminal defines the number of PDCCH candidates that can be monitored and the maximum number of CCEs that constitute the entire search space (here, the entire search space means the entire set of CCEs corresponding to the union area of ​​multiple search space sets) for each slot, and if r16monitoringcapability is set as the value of monitoringCapabilityConfig-r16, the terminal defines the number of PDCCH candidates that can be monitored and the maximum number of CCEs that constitute the entire search space (here, the entire search space means the entire set of CCEs corresponding to the union area of ​​multiple search space sets) for each span.

[0145] [Condition 1: Maximum number of PDCCH candidate groups]

[0146] As described above, the maximum number of PDCCH candidates that the terminal can monitor is determined by the setting value of higher layer signaling. μ is the subcarrier spacing of 15·2 μ In a cell set to kHz, if it is defined based on slot, it should follow Table 11 below, and if it is defined based on span, it should follow Table 12 below.

[0147] [Table 11]

[0148] [Table 12]

[0149] [Condition 2: Maximum CCE number limit]

[0150] As described above, the maximum number of CCEs constituting the entire search space (here, the entire search space means the entire CCE set corresponding to the union area of ​​a plurality of search space sets) is determined by the setting value of the upper layer signaling. μ is the subcarrier spacing of 15·2 μ In the case of a cell set to kHz, if it is defined based on a slot, it should follow Table 13 below, and if it is defined based on a span, it should follow Table 14 below.

[0151] [Table 13]

[0152] [Table 14]

[0153] For ease of explanation, a situation in which both conditions 1 and 2 are satisfied at a particular time point is defined as "condition A." Therefore, a situation in which condition A is not satisfied may mean that either one of conditions 1 or 2 is not satisfied.

[0154] [PDCCH: Overbooking]

[0155] Depending on the setting of the search space set of the base station, it may occur that condition A is not satisfied at a certain time. If condition A is not satisfied at a certain time, the terminal can select and monitor only a part of the search space set set to satisfy condition A at that time, and the base station can transmit the PDCCH to the selected search space set.

[0156] A method for selecting a part of search spaces from the entire set of search spaces may be as follows.

[0157] When condition A for PDCCH cannot be satisfied at a particular time (slot), the terminal (or base station) can select a search space set whose search space type is set to common search space from among the search space sets existing at that time, in preference to a search space set whose search space type is set to terminal-specific search space.

[0158] When all search space sets set as common search spaces are selected (i.e., when condition A is satisfied even after selecting all search spaces set as common search spaces), the terminal (or base station) can select a search space set set as terminal-specific search space. In this case, when there are multiple search space sets set as terminal-specific search spaces, a search space set with a low search space set index may have a relatively high priority. Taking the priority into consideration, a terminal-specific search space set can be selected within a range that satisfies condition A.

[0159] [Rate matching / puncturing related]

[0160] The rate matching operation and the puncturing operation will be described in detail below.

[0161] When a time and frequency resource A on which an arbitrary symbol sequence A is to be transmitted overlaps with an arbitrary time and frequency resource B, a rate matching or puncturing operation may be considered as a transmission / reception operation of channel A taking into account a region resource C where resource A and resource B overlap.

[0162] Rate Matching Operation

[0163] - The base station can map and transmit channel A only to the remaining resource area excluding resource C corresponding to the overlapping area with resource B among all resources A to which the base station wishes to transmit symbol sequence A to the terminal. For example, if symbol sequence A is composed of {symbol #1, symbol #2, symbol #3, symbol 4}, resource A is {resource #1, resource #2, resource #3, resource #4}, and resource B is {resource #3, resource #5}, the base station can sequentially map and transmit symbol sequence A to the remaining resources {resource #1, resource #2, resource #4} among resources A except {resource #3} corresponding to resource C. As a result, the base station can map and transmit the symbol sequence {symbol #1, symbol #2, symbol #3} to {resource #1, resource #2, resource #4}, respectively.

[0164] The terminal can determine resource A and resource B from scheduling information for symbol sequence A from the base station, and can therefore determine resource C, which is an area where resource A and resource B overlap. The terminal can receive symbol sequence A by assuming that symbol sequence A is mapped to the remaining area of ​​all resources A except resource C and transmitted. For example, if symbol sequence A is composed of {symbol #1, symbol #2, symbol #3, symbol 4}, resource A is {resource #1, resource #2, resource #3, resource #4}, and resource B is {resource #3, resource #5}, the terminal can receive symbol sequence A by assuming that symbol sequence A is sequentially mapped to the remaining resources {resource #1, resource #2, resource #4} except {resource #3} corresponding to resource C in resource A. As a result, the terminal can perform a series of subsequent reception operations by assuming that symbol sequence {symbol #1, symbol #2, symbol #3} is mapped to {resource #1, resource #2, resource #4} and transmitted.

[0165] Puncturing Operation

[0166] When a base station intends to transmit symbol sequence A to a terminal, if there is a resource C that corresponds to an area that overlaps with resource B among the total resources A, the base station maps symbol sequence A to the entire resource A, but does not transmit in the resource area corresponding to resource C. Instead, the base station can transmit only to the remaining resource area of ​​resource A excluding resource C. For example, if the symbol sequence A is composed of {symbol #1, symbol #2, symbol #3, symbol #4}, the resource A is {resource #1, resource #2, resource #3, resource #4}, and the resource B is {resource #3, resource #5}, the base station can map the symbol sequence A {symbol #1, symbol #2, symbol #3, symbol #4} to the resource A {resource #1, resource #2, resource #3, resource #4}, respectively, and transmit only the symbol sequence {symbol #1, symbol #2, symbol #4} corresponding to the remaining resource {resource #1, resource #2, resource #4} of the resource A except for {resource #3} corresponding to resource C, and do not need to transmit {symbol #3} mapped to {resource #3} corresponding to resource C. As a result, the base station can map the symbol sequence {symbol #1, symbol #2, symbol #4} to {resource #1, resource #2, resource #4}, respectively, and transmit it.

[0167] The terminal can determine resource A and resource B from scheduling information for symbol sequence A from the base station, and can therefore determine resource C, which is an overlapping region of resource A and resource B. The terminal can receive symbol sequence A assuming that symbol sequence A is mapped to the entire resource A but is transmitted only in the remaining region of resource region A excluding resource C. For example, if symbol sequence A is composed of {symbol #1, symbol #2, symbol #3, symbol #4}, resource A is {resource #1, resource #2, resource #3, resource #4}, and resource B is {resource #3, resource #5}, the terminal can assume that symbol sequence A {symbol #1, symbol #2, symbol #3, symbol #4} is mapped to resource A {resource #1, resource #2, resource #3, resource #4}, respectively, but {symbol #3} mapped to {resource #3} corresponding to resource C is not transmitted, and can receive by assuming that symbol sequence {symbol #1, symbol #2, symbol #4} corresponding to the remaining resource {resource #1, resource #2, resource #4} of resource A except {resource #3} corresponding to resource C is mapped and transmitted. As a result, the terminal can perform a series of subsequent receiving operations by assuming that symbol sequence {symbol #1, symbol #2, symbol #4} is mapped and transmitted to {resource #1, resource #2, resource #4}, respectively.

[0168] The following describes a method for setting rate matching resources for the purpose of rate matching in a 5G communication system. Rate matching means that the size of a signal is adjusted in consideration of the amount of resources that can transmit the signal. For example, rate matching of a data channel may mean that the data channel is not mapped to a specific time and frequency resource region and transmitted, thereby adjusting the size of the data.

[0169] FIG. 6 is a diagram illustrating a method in which a base station and a terminal transmit and receive data in consideration of a downlink data channel and a rate matching resource.

[0170] 6 shows a downlink data channel (PDSCH, 601) and rate matching resources 602. A base station can configure one or more rate matching resources 602 in a terminal through higher layer signaling (e.g., RRC signaling). Configuration information for the rate matching resources 602 may include time axis resource allocation information 603, frequency axis resource allocation information 604, and periodicity information 605. In the following, a bitmap corresponding to the frequency axis resource allocation information 604 is named a "first bitmap", a bitmap corresponding to the time axis resource allocation information 603 is named a "second bitmap", and a bitmap corresponding to the periodicity information 605 is named a "third bitmap". When all or part of the time and frequency resources of the scheduled data channel 601 overlap with the configured rate matching resources 602, the base station can rate-match and transmit the data channel 601 in the portion of the rate matching resources 602, and the terminal can receive and decode the data channel 601 after assuming that the data channel 601 has been rate-matched in the portion of the rate matching resources 602.

[0171] By additional configuration, the base station can dynamically notify the terminal by DCI whether or not to rate match the data channel in the configured rate matching resource portion (corresponding to the "rate matching indicator" in the DCI format described above). Specifically, the base station can select a part of the configured rate matching resources and group them into rate matching resource groups, and can instruct the terminal by DCI using a bitmap method whether or not to perform rate matching of the data channel for each rate matching resource group. For example, when four rate matching resources, RMR#1, RMR#2, RMR#3, and RMR#4, are configured, the base station can set RMG#1={RMR#1, RMR#2} and RMG#2={RMR#3, RMR#4} as rate matching groups, and can use two bits in the DCI field to instruct the terminal by bitmap whether or not to perform rate matching in RMG#1 and RMG#2, respectively.

[0172] For example, if rate matching should be performed, it can be instructed as "1", and if rate matching should not be performed, it can be instructed as "0".

[0173] In 5G, as a method of setting the above-mentioned rate matching resource to a terminal, granularity of "RB symbol level" and "RE level" is supported. More specifically, the following setting method may be used.

[0174] RB Symbol Level

[0175] The terminal can receive up to four RateMatchPattern settings for each bandwidth portion through higher layer signaling, and one RateMatchPattern may include the following contents.

[0176] - A reserved resource in a bandwidth portion may include a resource in which a time and frequency resource domain of the reserved resource is set by a combination of an RB level bitmap and a symbol level bitmap on a frequency axis. The reserved resource may span one or two slots. A time domain pattern (periodicityAndPattern) in which the time and frequency domains configured by each RB level and symbol level bitmap pair are repeated may be further set.

[0177] -The control resource set within the bandwidth portion may include a time and frequency domain resource region configured as a control resource set, and a resource region corresponding to a time domain pattern configured as a search space setting in which the resource region is repeated.

[0178] RE Level

[0179] The terminal can receive the following settings through higher layer signaling:

[0180] - The configuration information (lte-CRS-ToMatchAround) for the RE corresponding to the LTE CRS (Cell-specific Reference Signal or Common Reference Signal) pattern may include the number of ports (nrofCRS-Ports) of the LTE CRS, the LTE-CRS-vshift(s) value (v-shift), the center subcarrier (Subcarrier) position information (carrierFreqDL) of the LTE carrier from the reference frequency point (e.g., reference point A), the bandwidth size (carrierBandwidthDL) information of the LTE carrier, subframe configuration information (mbsfn-SubframConfigList) corresponding to the MBSFN (Multicast-broadcast single-frequency network), etc. The UE can determine the position of the CRS in the NR slot corresponding to the LTE subframe based on the above information.

[0181] - It may include configuration information for a resource set corresponding to one or more Zero Power (ZP) CSI-RS within the bandwidth portion.

[0182] [LTE CRS rate match related]

[0183] For coexistence between LTE and NR (LTE-NR Coexistence), NR provides a function for setting a pattern of LTE's Cell Specific Reference Signal (CRS) in an NR terminal. More specifically, the CRS pattern may be provided by RRC signaling including at least one parameter in a ServingCellConfig IE (Information Element) or a ServingCellConfigCommon IE. Examples of the parameters may include lte-CRS-ToMatchAround, lte-CRS-PatternList1-r16, lte-CRS-PatternList2-r16, and crs-RateMatch-PerCORESETPoolIndex-r16.

[0184] In Rel-15NR, a function is provided that allows one CRS pattern to be configured per serving cell by the lte-CRS-ToMatchAround parameter. In Rel-16NR, the function is extended to allow multiple CRS patterns to be configured per serving cell. More specifically, a single-TRP (transmission and reception point) configured terminal may be configured with one CRS pattern per LTE carrier, and a multi-TRP configured terminal may be configured with two CRS patterns per LTE carrier. For example, a single-TRP configured terminal may be configured with up to three CRS patterns per serving cell by using the lte-CRS-PatternList1-r16 parameter.

[0185] As another example, a CRS may be configured for each TRP in a multi-TRP configured terminal. That is, a CRS pattern for TRP1 may be configured by the lte-CRS-PatternList1-r16 parameter, and a CRS pattern for TRP2 may be configured by the lte-CRS-PatternList2-r16 parameter. In this way, when two TRPs are configured, whether to apply all the CRS patterns of TRP1 and TRP2 to a specific PDSCH (Physical Downlink Shared Channel) or to apply only the CRS pattern for one TRP is determined by the crs-RateMatch-PerCORESETPoolIndex-r16 parameter. When the crs-RateMatch-PerCORESETPoolIndex-r16 parameter is set to enabled, only the CRS pattern of one TRP is applied, and in other cases, both the CRS patterns of both TRPs are applied.

[0186] Table 15 shows a ServingCellConfig IE that includes the CRS pattern, and Table 16 shows a RateMatchPatternLTE-CRS IE that includes at least one parameter for the CRS pattern.

[0187] [Table 15A] [Table 15B] [Table 15C]

[0188] [Table 16]

[0189] [PDSCH: Frequency resource allocation related]

[0190] 7 illustrates frequency axis resource allocation of a PDSCH (physical downlink shared channel) in a wireless communication system according to an embodiment of the present disclosure. More specifically, FIG. 7 illustrates three frequency axis resource allocation methods, namely, type 0 (7-00), type 1 (7-05), and dynamic switch (7-10), which can be set by a higher layer in an NR wireless communication system.

[0191] Referring to FIG 7, if a terminal is configured to use only resource type 0 by higher layer signaling (7-00), some downlink control information (DCI) for allocating a PDSCH to the terminal includes a bitmap consisting of number of resource block group (NRBG) bits. NRBG means the number of resource block groups (RBGs) determined according to the BWP size allocated by a BWP indicator and the higher layer parameter rbg-Size as shown in Table 17 below, and data is transmitted in the RBG indicated as 1 by the bitmap.

[0192] [Table 17]

[0193] If a terminal is configured to use only resource type 1 by higher layer signaling (7-05), some DCIs that allocate PDSCH to the terminal are

number

[0194] If a terminal is configured to use both resource type 0 and resource type 1 by higher layer signaling (7-10), a portion of DCI that allocates a PDSCH to the terminal includes frequency axis resource allocation information consisting of the larger value (7-35) of payload (7-15) for setting resource type 0 and payloads 7-20 and 7-25 for setting resource type 1. In this case, one bit may be added to the very beginning (i.e., the MSB) of the frequency axis resource allocation information in the DCI, and if the bit has a value of "0", it may indicate that resource type 0 is used, and if the bit has a value of "1", it may indicate that resource type 1 is used.

[0195] [PDSCH / PUSCH: Time resource allocation related]

[0196] In the following, a time domain resource allocation method for a data channel in a next generation mobile communication system (5G or NR system) is described.

[0197] The base station may configure a table for time domain resource allocation information for a downlink data channel (Physical Downlink Shared Channel, PDSCH) and an uplink data channel (Physical Uplink Shared Channel, PUSCH) in the terminal through higher layer signaling (e.g., RRC signaling). For the PDSCH, a table configured with a maximum of maxNrofDL-Allocations=16 entries may be configured, and for the PUSCH, a table configured with a maximum of maxNrofUL-Allocations=16 entries may be configured. In one embodiment, the time domain resource allocation information may include PDCCH-to-PDSCH slot timing (corresponding to a time interval in slot units between a time when a PDCCH is received and a time when a PDSCH scheduled by the received PDCCH is transmitted, represented by K0), PDCCH-to-PUSCH slot timing (corresponding to a time interval in slot units between a time when a PDCCH is received and a time when a PUSCH scheduled by the received PDCCH is transmitted, represented by K2), information on a position and length of a start symbol in which a PDSCH or PUSCH is scheduled in a slot, a mapping type of a PDSCH or PUSCH, etc. For example, information such as the following Table 18 or Table 19 may be transmitted from the base station to the terminal.

[0198] [Table 18]

[0199] [Table 19]

[0200] The base station can notify the terminal of one of the entries of the table for the above-mentioned time domain resource allocation information by using L1 (layer 1) signaling (e.g., DCI) (e.g., the "time domain resource allocation" field in the DCI can be indicated). The terminal can obtain the time domain resource allocation information for the PDSCH or the PUSCH based on the DCI received from the base station.

[0201] FIG. 8 illustrates time axis resource allocation of a PDSCH in a wireless communication system according to an embodiment of the present disclosure.

[0202] Referring to FIG. 8, the base station determines the subcarrier spacing (SCS) (μ PDSCH ,μ PDCCH ), the scheduling offset (K0) value, and the time axis position of the PDSCH resource can be indicated by the OFDM symbol start position 8-00 and length 8-05 within one slot that are dynamically indicated by the DCI.

[0203] FIG. 9 is a diagram illustrating time axis resource allocation based on subcarrier spacing of a data channel and a control channel in a wireless communication system according to an embodiment of the present disclosure.

[0204] Referring to FIG. 9, when the subcarrier intervals of the data channel and the control channel are the same, 9-00(μ PDSCH =μ PDCCH ), the slot numbers for data and control are the same, so the base station and the terminal can generate a scheduling offset according to a predetermined slot offset K0. On the other hand, when the subcarrier intervals of the data channel and the control channel are different, 9-05 (μ PDSCH ≠μPDCCH Since the slot numbers for data and control are different in the PDCCH, the base station and the terminal can generate a scheduling offset according to a predetermined slot offset K0 based on the subcarrier spacing of the PDCCH.

[0205] [PUSCH: Transmission method related]

[0206] PUSCH transmission may be dynamically scheduled by a UL grant in DCI and may operate according to configured grant Type 1 or Type 2. Dynamic scheduling instructions for PUSCH transmission are possible in DCI format 0_0 or 0_1.

[0207] Configured grant Type 1 PUSCH transmission may be semi-statically configured by receiving configuredGrantConfig including rrc-ConfiguredUplinkGrant in Table 20 using higher level signaling without receiving UL grant in DCI. Configured grant Type 2 PUSCH transmission may be semi-persistently scheduled by UL grant in DCI after receiving configuredGrantConfig not including rrc-ConfiguredUplinkGrant in Table 20 using higher level signaling. When PUSCH transmission is operated by configured grant, parameters applied to PUSCH transmission are applied by configuredGrantConfig, which is higher level signaling in Table 20, except for dataScramblingIdentityPUSCH, txConfig, codebookSubset, maxRank, and scaling of UCI-OnPUSCH, which are provided as pusch-Config in Table 21, which is higher level signaling. When the terminal receives transformPrecoder in configuredGrantConfig, which is the higher level signaling in Table 20, the terminal applies tp-pi2BPSK in pusch-Config in Table 21 to PUSCH transmission operated according to the configured grant.

[0208] [Table 20A] [Table 20B]

[0209] The DMRS antenna port for PUSCH transmission may be the same as the antenna port for SRS transmission. The PUSCH transmission may follow a codebook-based transmission method or a non-codebook-based transmission method depending on whether the value of txConfig in pusch-Config in Table 21, which is higher-level signaling, is "codebook" or "nonCodebook."

[0210] As described above, PUSCH transmission may be dynamically scheduled by DCI format 0_0 or 0_1, or may be semi-statically set by configured grant. If the terminal receives a scheduling instruction for PUSCH transmission by DCI format 0_0, the terminal performs beam configuration for PUSCH transmission using pucch-spatialRelationInfoID corresponding to a terminal-specific PUCCH resource corresponding to the smallest ID in an activated uplink BWP in a serving cell, and at this time, PUSCH transmission is based on a single antenna port. The terminal does not expect scheduling for PUSCH transmission by DCI format 0_0 in a BWP in which a PUCCH resource including pucch-spatialRelationInfo is not configured. If the terminal does not receive a configuration of txConfig in pusch-Config in Table 21, the terminal does not expect to be scheduled by DCI format 0_1.

[0211] [Table 21]

[0212] Codebook-based PUSCH transmission may be dynamically scheduled by DCI format 0_0 or 0_1, or may operate semi-statically by configured grant. When Codebook-based PUSCH is dynamically scheduled by DCI format 0_1 ​​or semi-statically configured by configured grant, the terminal determines a precoder for PUSCH transmission based on an SRS Resource Indicator (SRI), a Transmission Precoding Matrix Indicator (TPMI), and a transmission rank (the number of PUSCH transmission layers).

[0213] The SRI may be given by the SRI field in the DCI or may be configured by the srs-ResourceIndicator, which is higher-level signaling. At least one SRS resource may be configured in the terminal when transmitting a codebook-based PUSCH, and up to two SRS resources may be configured. When the terminal receives an SRI in the DCI, the SRS resource indicated by the SRI means an SRS resource corresponding to the SRI among SRS resources transmitted before the PDCCH including the SRI. In addition, the TPMI and the transmission rank may be given by the precoding information and number of layers field in the DCI or may be configured by precodingAndNumberOfLayers, which is higher-level signaling. The TPMI may be used to indicate a precoder to be applied to PUSCH transmission. If the terminal receives a configuration of one SRS resource, the TPMI is used to indicate a precoder to be applied to the configured one SRS resource. If the terminal receives a configuration of multiple SRS resources, the TPMI is used to indicate the precoder to be applied to the SRS resource indicated by the SRI.

[0214] The precoder used for PUSCH transmission is selected from an uplink codebook having the same number of antenna ports as the nrofSRS-Ports value in the SRS-Config, which is higher-level signaling.

[0215] In the codebook-based PUSCH transmission, the terminal determines the codebook subset based on the TPMI and the codebookSubset in the higher-level signaling pusch-Config. The codebookSubset in the higher-level signaling pusch-Config may be set to one of "fullyAndPartialAndNonCoherent", "partialAndNonCoherent", or "nonCoherent" based on the UE capability reported by the terminal to the base station.

[0216] If the terminal reports "partialAndNonCoherent" as the UE capability, the terminal does not expect the value of codebookSubset, which is higher-level signaling, to be set to "fullyAndPartialAndNonCoherent". Also, if the terminal reports "nonCoherent" as the UE capability, the terminal does not expect the value of codebookSubset, which is higher-level signaling, to be set to "fullyAndPartialAndNonCoherent" or "partialAndNonCoherent". When nrofSRS-Ports in SRS-ResourceSet, which is higher-level signaling, indicates two SRS antenna ports, the terminal does not expect the value of codebookSubset, which is higher-level signaling, to be set to "partialAndNonCoherent".

[0217] The terminal may be configured with one SRS resource set in which the value of usage in SRS-ResourceSet, which is higher-level signaling, is set to "codebook", and one SRS resource in the SRS resource set may be indicated by the SRI. If multiple SRS resources are configured in an SRS resource set in which the value of usage in SRS-ResourceSet, which is higher-level signaling, is set to "codebook", the terminal expects that the value of nrofSRS-Ports in SRS-Resource, which is higher-level signaling, is set to the same value for all SRS resources.

[0218] The terminal transmits one or more SRS resources included in an SRS resource set in which the value of usage is set to "codebook" to the base station by higher-level signaling, and the base station selects one of the SRS resources transmitted by the terminal and instructs the terminal to transmit a PUSCH using transmission beam information of the SRS resource. In codebook-based PUSCH transmission, the SRI is used as information for selecting an index of one SRS resource and is included in the DCI. Furthermore, the base station includes information indicating the TPMI and rank used by the terminal for PUSCH transmission in the DCI. The terminal transmits a PUSCH using the SRS resource indicated by the SRI, applying the rank indicated based on the transmission beam of the SRS resource and the precoder indicated by the TPMI.

[0219] Non-codebook-based PUSCH transmission may be dynamically scheduled by DCI format 0_0 or 0_1, or may operate semi-statically by configured grant. When at least one SRS resource is configured in an SRS resource set in which the value of usage in SRS-ResourceSet, which is higher-level signaling, is set to "nonCodebook", the terminal may be scheduled for non-codebook-based PUSCH transmission by DCI format 0_1.

[0220] For an SRS resource set in which the value of usage in the higher-level signaling SRS-ResourceSet is set to "nonCodebook", the terminal may be configured with one connected non-zero power CSI-RS (NZP CSI-RS). The terminal may perform calculations on a precoder for SRS transmission based on measurements on the NZP CSI-RS resources connected to the SRS resource set. If the difference between the last received symbol of the aperiodic NZP CSI-RS resource connected to the SRS resource set and the first symbol of the aperiodic SRS transmission in the terminal is less than 42 symbols, the terminal does not expect information on the precoder for SRS transmission to be updated.

[0221] When the value of resourceType in the SRS-ResourceSet, which is higher-level signaling, is set to "aperiodic", the connected NZP CSI-RS is indicated by the SRS request field in DCI format 0_1 ​​or 1_1. In this case, if the connected NZP CSI-RS resource is an aperiodic NZP CSI-RS resource, the value of the SRS request field in DCI format 0_1 ​​or 1_1 indicates the presence of the connected NZP CSI-RS unless it is "00". The DCI should not indicate cross carrier or cross BWP scheduling. In addition, if the value of the SRS request indicates the presence of the NZP CSI-RS, the NZP CSI-RS is located in the slot in which the PDCCH including the SRS request field is transmitted. The TCI state set to the scheduled subcarrier is not set to QCL-TypeD.

[0222] If a periodic or semi-persistent SRS resource set is configured, the linked NZP CSI-RS may be indicated by the associated CSI-RS in the higher level signaling SRS-ResourceSet. For non-codebook-based transmission, the UE does not expect that both the higher level signaling spatialRelationInfo for the SRS resource and the associated CSI-RS in the higher level signaling SRS-ResourceSet are configured.

[0223] When multiple SRS resources are configured, the terminal can determine the precoder and transmission rank to be applied to PUSCH transmission based on the SRI indicated by the base station. The SRI may be indicated by the field SRS resource indicator in the DCI, or may be set by the srs-ResourceIndicator, which is higher-level signaling. As in the above-mentioned codebook-based PUSCH transmission, when the terminal receives the SRI through the DCI, the SRS resource indicated by the SRI means the SRS resource corresponding to the SRI among the SRS resources transmitted before the PDCCH including the SRI. The terminal can use one or multiple SRS resources for SRS transmission, and the maximum number of SRS resources and the maximum number of SRS resources that can be simultaneously transmitted with the same symbol in one SRS resource set are determined by the UE capability reported by the terminal to the base station. In this case, the SRS resources simultaneously transmitted by the terminal occupy the same RB. The terminal configures one SRS port for each SRS resource. Only one SRS resource set in which the value of usage in the higher-level signaling SRS-ResourceSet is set to "nonCodebook" may be configured, and up to four SRS resources for non-codebook-based PUSCH transmission may be configured.

[0224] The base station transmits one NZP-CSI-RS concatenated with the SRS resource set to the terminal, and the terminal calculates a precoder to be used when transmitting one or more SRS resources in the SRS resource set based on a measurement result when receiving the NZP-CSI-RS. The terminal applies the calculated precoder when transmitting one or more SRS resources in the SRS resource set with usage set to "nonCodebook" to the base station, and the base station selects one or more SRS resources from the received one or more SRS resources. In this case, in non-codebook-based PUSCH transmission, the SRI represents an index capable of expressing a combination of one or more SRS resources, and the SRI is included in the DCI. In this case, the number of SRS resources indicated by the SRI transmitted by the base station may be the number of transmission layers of the PUSCH, and the terminal transmits the PUSCH by applying a precoder applied to the SRS resource transmission to each layer.

[0225] [PUSCH: Preparation process time]

[0226] When the base station schedules the terminal to transmit the PUSCH using DCI format 0_0, 0_1, or 0_2, the terminal may need a PUSCH preparation process time to transmit the PUSCH by applying the transmission method (SRS resource transmission precoding method, number of transmission layers, spatial domain transmission filter) indicated in the DCI. In NR, the PUSCH preparation process time is defined taking this into consideration. The PUSCH preparation process time of the terminal may be as follows:

[0227] [Formula 2]

[0228]

number

[0229] T in Equation 2 proc,2 where each variable can have the following meaning:

[0230] - N 2 : The number of symbols determined by UE processing capability 1 or 2 and numerology μ according to the capability of the terminal. When the terminal processing capability 1 is reported by the capability report of the terminal, it has the value of Table 22, and when the terminal processing capability 2 is reported and it is set by higher layer signaling that the terminal processing capability 2 can be used, it can have the value of Table 23.

[0231] [Table 22]

[0232] [Table 23]

[0233] -d 2,1 : The number of symbols determined to be 0 if all resource elements of the first OFDM symbol of PUSCH transmission are set to consist of only DM-RS, and 1 if not.

[0234] - K:64

[0235] - μ:μ DL Or μ UL Of these, T proc,2 follows the larger value of μ DL means the downlink numerology in which the PDCCH including the DCI for scheduling the PUSCH is transmitted, and μ UL means the numerology of the uplink on which the PUSCH is transmitted.

[0236] - T c :1 / (Δf max *N f ), Δf max =480*103Hz, N f = 4096.

[0237] -d 2,2 : According to the BWP switching time if the DCI scheduling the PUSCH indicates BWP switching, otherwise has 0.

[0238] -d 2 When the OFDM symbols of the PUCCH, the PUSCH having a high priority index, and the PUCCH having a low priority index overlap in time, the d 2 value is used, otherwise d 2 is 0.

[0239] - T ext When the terminal uses a shared spectrum channel access method, the terminal ext can be calculated and applied to the PUSCH preparation process time. Otherwise, T ext is assumed to be 0.

[0240] - T switch : When the uplink switching interval is triggered, T switch is assumed to be the switching interval time, otherwise it is assumed to be 0.

[0241] When considering the time axis resource mapping information of the PUSCH scheduled in the DCI and the influence of the uplink-downlink timing advance, the base station and the terminal determine whether the PUSCH is scheduled for the last symbol of the PDCCH including the DCI. proc,2 If the first symbol of the PUSCH starts before the first uplink symbol where the CP starts, the base station and the terminal determine that the PUSCH preparation process time is sufficient. The terminal transmits the PUSCH only if the PUSCH preparation process time is sufficient, and if the PUSCH preparation process time is not sufficient, the terminal can ignore the DCI that schedules the PUSCH.

[0242] [CA / DC related]

[0243] FIG. 10 is a diagram illustrating radio protocol structures of a base station and a terminal in a single cell environment, a carrier aggregation environment, and a dual connectivity environment according to an embodiment of the present disclosure.

[0244] Referring to Figure 10, the radio protocols of the next-generation mobile communication system consist of NR SDAP (Service Data Adaptation Protocol S25, S70), NR PDCP (Packet Data Convergence Protocol S30, S65), NR RLC (Radio Link Control S35, S60), and NR MAC (Medium Access Control S40, S55) in the terminal and NR base station, respectively.

[0245] The main functions of the NR SDAP (S25, S70) may include at least some of the following functions:

[0246] - Transfer of user plane data

[0247] - Mapping function between a QoS flow and a DRB for both DL and UL

[0248] - Marking QoS flow ID in both DL and UL packets

[0249] - The ability to map reflective QoS flow to data bearers for the uplink SDAP PDUs (reflective QoS flow to DRB mapping for the UL SDAP PDUs).

[0250] For the SDAP layer device, the terminal may set in the RRC message whether to use the header of the SDAP layer device or whether to use the function of the SDAP layer device for each PDCP layer device, bearer, or logical channel, and when the SDAP header is set, the NAS reflective setting 1-bit indicator (NAS reflective QoS) and the AS reflective setting 1-bit indicator (AS reflective QoS) of the SDAP header may instruct the terminal to update or reset the mapping information for the uplink and downlink QoS flows and the data bearers. The SDAP header may include QoS flow ID information indicating QoS. The QoS information may be used as data processing priority, scheduling information, etc. to support smooth service.

[0251] The main functions of the NR PDCP (S30, S65) may include at least some of the following functions.

[0252] - Header compression and decompression (ROHC only)

[0253] - Transfer of user data

[0254] - In-sequence delivery of upper layer PDUs

[0255] - Out-of-sequence delivery of upper layer PDUs

[0256] - Reordering function (PDCP PDU reordering for reception)

[0257] - Duplicate detection of lower layer SDUs

[0258] - Retransmission of PDCP SDUs

[0259] - Ciphering and deciphering functions

[0260] - Timer-based SDU discard in uplink

[0261] In the above, the reordering function of the NR PDCP device refers to a function of sequentially reordering PDCP PDUs received from a lower layer based on PDCP sequence number (SN), and may include a function of transmitting data to a higher layer in the reordered order. Alternatively, the reordering function of the NR PDCP device may include a function of immediately transmitting data without considering the order, a function of recording PDCP PDUs lost due to reordering, a function of reporting a status of the lost PDCP PDU to the transmitting side, and a function of requesting retransmission of the lost PDCP PDU.

[0262] The main functions of NR RLC (S35, S60) may include at least some of the following functions:

[0263] - Data transmission function (Transfer of upper layer PDUs)

[0264] - In-sequence delivery of upper layer PDUs

[0265] - Out-of-sequence delivery of upper layer PDUs

[0266] - ARQ function (Error Correction through ARQ)

[0267] - Concatenation, segmentation and reassembly of RLC SDUs

[0268] - Re-segmentation of RLC data PDUs

[0269] - Reordering of RLC data PDUs

[0270] - Duplicate detection

[0271] - Protocol error detection

[0272] - RLC SDU deletion function (RLC SDU discard)

[0273] - RLC re-establishment function

[0274] In the above, the in-sequence delivery function of the NR RLC device means a function of delivering RLC SDUs received from a lower layer to a higher layer in sequence. The in-sequence delivery function of the NR RLC device may include a function of reassembling and delivering one original RLC SDU when it is divided into several RLC SDUs and received, a function of reordering received RLC PDUs based on RLC sequence number (SN) or PDCP sequence number (SN), a function of recording RLC PDUs lost due to reordering, a function of reporting the status of lost RLC PDUs to a transmitting side, and a function of requesting retransmission of lost RLC PDUs. The in-sequence delivery function of the NR RLC device may include a function of sequentially delivering only RLC SDUs up to the lost RLC SDU to the upper layer when an RLC SDU is lost, or may include a function of sequentially delivering all RLC SDUs received before a timer starts to the upper layer when a predetermined timer expires, even if an RLC SDU is lost.

[0275] Alternatively, the in-sequence delivery function of the NR RLC device may include a function of sequentially delivering all RLC SDUs received up to now to the upper layer when a certain timer expires, even if there is a lost RLC SDU. Also, the RLC PDUs can be processed in the order in which they are received (in the order in which they arrive, regardless of the order of sequence numbers) and delivered out of sequence (out-of-sequence delivery) to the PDCP device, or in the case of a segment, a segment stored in a buffer can be received and later received, reconstructed as one complete RLC PDU, and then processed and delivered to the PDCP device. The NR RLC layer may not include a concatenation function, and the function may be performed by the NR MAC layer, or may be replaced by the multiplexing function of the NR MAC layer.

[0276] In the above, the out-of-sequence delivery function of the NR RLC device refers to a function of immediately delivering RLC SDUs received from a lower layer to a higher layer regardless of the order, and may include a function of reassembling and delivering an original RLC SDU when it is received in a fragmented form into several RLC SDUs, and may include a function of saving the RLC SN or PDCP SN of the received RLC PDU, sorting the order, and recording lost RLC PDUs.

[0277] The NR MAC (S40, S55) may be connected to multiple NR RLC layer devices configured in one terminal, and the main functions of the NR MAC may include at least some of the following functions.

[0278] - Mapping function (Mapping between logical channels and transport channels)

[0279] - Multiplexing / demultiplexing of MAC SDUs

[0280] - Scheduling information reporting function

[0281] - HARQ function (Error correction through HARQ)

[0282] -Priority handling between logical channels of one UE

[0283] - Priority handling between UEs by means of dynamic scheduling

[0284] - MBMS (multimedia broadcast multicast services) service identification function (MBMS service identification)

[0285] - Transport format selection

[0286] - Padding function

[0287] The NR PHY layer (S45, S50) can perform channel coding and modulation of upper layer data, converting it into OFDM symbols and transmitting them over a wireless channel, or demodulating the OFDM symbols received over a wireless channel, channel decoding them, and transmitting them to an upper layer.

[0288] The radio protocol structure may be modified in detail according to the carrier (or cell) operation method. For example, when a base station transmits data to a terminal based on a single carrier (or cell), the base station and the terminal use a protocol structure having a single structure for each layer, as in (S00). On the other hand, when a base station transmits data to a terminal based on carrier aggregation (CA) using multiple carriers in a single TRP, the base station and the terminal use a protocol structure having a single structure up to RLC, as in (S10), but multiplexing the PHY layer through the MAC layer.

[0289] As yet another example, when a base station transmits data to a terminal based on dual connectivity (DC) using multiple carriers in multiple TRPs, the base station and the terminal have a single structure up to RLC, as in (S20), but use a protocol structure that multiplexes the PHY layer through the MAC layer.

[0290] Referring to the above description of PDCCH and beam setting, currently Rel-15 and Rel-16NR do not support PDCCH repeated transmission, and it is difficult to achieve the required reliability in scenarios requiring high reliability such as URLLC. In the present disclosure, a method for PDCCH repeated transmission using multiple transmission points (TRPs) is provided to improve the PDCCH reception reliability of a terminal. A specific method will be described in detail in the following embodiments.

[0291] Hereinafter, the embodiments of the present disclosure are applicable to FDD and TDD systems. Upper layer signaling (or upper layer signaling) is a signal transmission method transmitted from a base station to a terminal using a downlink data channel of a physical layer, or from a terminal to a base station using an uplink data channel of a physical layer, and may be called RRC signaling, PDCP signaling, or MAC (medium access control) control element (MAC control element; MAC CE).

[0292] Hereinafter, in the present disclosure, when determining whether to apply cooperative communication, the terminal can use various methods such as a PDCCH to which a PDSCH to which cooperative communication is applied has a specific format, or a PDCCH to which a PDSCH to which cooperative communication is applied includes a specific indicator indicating whether cooperative communication is applied, or a PDCCH to which a PDSCH to which cooperative communication is applied is scrambled with a specific RNTI, or an application of cooperative communication is assumed in a specific interval indicated by a higher layer. Hereinafter, for convenience of explanation, a case in which a terminal receives a PDSCH to which cooperative communication is applied based on a condition similar to the above is referred to as an NC-JT (non-coherent joint transmission) case.

[0293] Determining the priority between A and B may be expressed in various ways, such as selecting the one with a relatively high priority and performing the corresponding action according to a predetermined priority rule, or omitting or dropping the action for the one with a relatively low priority.

[0294] In the following, the present disclosure will explain the above-mentioned example using a number of examples, which are not necessarily independent, and one or more of the examples may be applied simultaneously or in combination.

[0295] The higher layer signaling may be signaling corresponding to at least one or a combination of one or more of the following signaling:

[0296] - MIB(Master Information Block)

[0297] - SIB (System Information Block) or SIB X (X=1,2,…)

[0298] - RRC (Radio Resource Control)

[0299] - MAC(Medium Access Control)CE(Control Element)

[0300] Furthermore, the L1 signaling may be signaling corresponding to at least one or a combination of one or more of the signaling methods using the following physical layer channels or signaling:

[0301] - PDCCH(Physical Downlink Control Channel)

[0302] - DCI(Downlink Control Information)

[0303] - UE-specific DCI

[0304] - Group common DCI

[0305] - Common DCI

[0306] - Scheduling DCI (e.g., DCI used for the purpose of scheduling downlink or uplink data)

[0307] - Non-scheduling DCI (e.g., DCI not intended to schedule downlink or uplink data)

[0308] - PUCCH(Physical Uplink Control Channel)

[0309] - UCI(Uplink Control Information)

[0310] The present disclosure provides a PDSCH rate-matching method and a PUCCH resource determination method by monitoring PDCCH repetition transmission when the PDCCH repetition transmission is configured in a terminal.

[0311] The base station may repeatedly transmit the PDCCH to provide the terminal with higher PDCCH reception reliability. Here, the repeatedly transmitted PDCCH may include the same DCI. Hereinafter, for convenience of explanation, the repeatedly transmitted PDCCH is referred to as PDCCH repeated transmission. For the PDCCH repeated transmission, the base station may configure at least one of the following information (e.g., first information, second information, third information, etc.) in the terminal.

[0312] In the first information, the base station may set two or more search spaces for the terminal. The terminal may monitor (or receive) the PDCCH using blind decoding in the search spaces. Each of the search spaces may be distinguished by a unique index (or ID (identity)). Each search space configuration may include at least one of the following information:

[0313] The search space configuration may include information about the CORESET to which the search space belongs. For example, each search space may belong to the same CORESET or may belong to a different CORESET.

[0314] The search space configuration may include information regarding the number of PDCCH candidates for each aggregation level in the search space, where at least 1, 2, 4, 8, and 16 aggregation levels may be supported.

[0315] The search space configuration may include information about a symbol (i.e., time) for a PDCCH monitoring occasion (PDCCH MO). The information may include a slot-based period and offset, and information about a symbol at which a PDCCH monitoring occasion starts in a slot. Here, the information about a symbol at which a PDCCH monitoring occasion starts in a slot may be represented by a bitmap (e.g., 14 bits), and the N-th bit of the bitmap indicates whether a PDCCH monitoring occasion starts at the N-th OFDM symbol in a slot. If the N-th bit of the bitmap is '1', the PDCCH monitoring occasion starts at the N-th OFDM symbol in a slot. If the N-th bit of the bitmap is '0', the PDCCH monitoring occasion does not start at the N-th OFDM symbol in a slot.

[0316] In the second information, the base station may configure two or more search spaces in which the PDCCH is repeatedly transmitted to the terminal. The base station may configure the two or more search spaces in which the PDCCH is repeatedly transmitted to the terminal using indexes (or IDs (identities)) of the two or more search spaces in which the PDCCH is repeatedly transmitted. Here, the search spaces in which the PDCCH is repeatedly transmitted may be expressed as being linked to each other. For reference, the two linked search spaces may have the same aggregation level (e.g., 1, 2, 4, 8, 16) and the same number of PDCCH candidates per aggregation level.

[0317] More specifically, the second information may be set in one of the following two ways.

[0318] First setting method: A base station may set a search space group for PDCCH repeated transmission, and the search space group may include at least two search spaces. The search space group may be divided by a unique index (or ID (identity)). The search spaces included in the search space group may be set by a search space unique index (or ID (identity)). Exemplarily, a base station may set a search space group 1 for PDCCH repeated transmission, and set indexes (or IDs (identities)) of each search space {1, 2} to a terminal to include search space 1 and search space 2 in search space group 1. In other words, indexes (or IDs (identities)) of search spaces {1, 2} may be set corresponding to the index (or ID (identity)) of search space group 1.

[0319] Second setting method: When setting each search space for PDCCH repeated transmission, the base station may set an index (or ID) of each search space and a linked search space. For example, in order to link search space 1 and search space 2, when setting search space 1, the base station may include information indicating that search space 2 is linked to the setting of search space 1. Similarly, when setting search space 2, the base station may include information indicating that search space 1 is linked to the setting of search space 2. As an example, the "information indicating linking" may be an index (or ID (identity)) of the linked search space. Furthermore, when setting each search space, a unique index (or ID (identity)) of the search space or a search space group composed of linked search spaces may be set.

[0320] In the above example, when setting search space 1, the setting of search space 1 may be set to include information indicating that search space 2 is linked (e.g., an index of search space 2) and information indicating that the search space 1 and search space 2 are included in search space group 1 (e.g., an index of search space group 1). Similarly, when setting search space 2, the base station may set the setting of search space 2 to include information indicating that search space 1 is linked (e.g., an index of search space 1) and information indicating that the search space 2 and search space 1 are included in search space group 1 (e.g., an index of search space group 1). The "information indicating inclusion in a search space group" may be a unique index (or ID (identity)) of the search space group.

[0321] As described above, the two linked search spaces may have the same aggregation level (e.g., 1, 2, 4, 8, 16) and the same number of PDCCH candidates per aggregation level. The terminal may assume that the same DCI is transmitted for PDCCH candidates corresponding to the same index at the same aggregation level (e.g., 1, 2, 4, 8, 16) in the two search spaces. As a specific example, the linked search spaces may be assumed to be search space 1 and search space 2. In search space 1 and search space 2, it may be assumed that two PDCCH candidates of aggregation level 4 (index=0 and index=1) are configured, and one PDCCH candidate of aggregation level 8 (index=0) is configured. In this case, the same DCI may be transmitted for the first PDCCH candidate (index=0) whose aggregation level of search space 1 and search space 2 is 4, the same DCI may be transmitted for the second PDCCH candidate (index=1) whose aggregation level of search space 1 and search space 2 is 4, and the same DCI may be transmitted for the PDCCH candidate (index=0) whose aggregation level of search space 1 and search space 2 is 8. Therefore, the terminal can receive the same DCI for the PDCCH candidates of each search space based on the configuration information of the linked search spaces (the same aggregation level (e.g., 1, 2, 4, 8, 16) and the same number of PDCCH candidates per aggregation level).

[0322] In the following description, it may be assumed that PDCCH candidates corresponding to the same index at the same aggregation level (e.g., 1, 2, 4, 8, 16) in two search spaces are linked. In the above example, the first PDCCH candidate (index=0) with an aggregation level of 4 in search space 1 is linked to the first PDCCH candidate (index=0) with an aggregation level of 4 in search space 2, the second PDCCH candidate (index=1) with an aggregation level of 4 in search space 1 is linked to the second PDCCH candidate (index=1) with an aggregation level of 4 in search space 2, and the first PDCCH candidate (index=0) with an aggregation level of 8 in search space 1 is linked to the first PDCCH candidate (index=0) with an aggregation level of 8 in search space 2.

[0323] When a base station links two or more search spaces, the base station must always transmit the same DCI in the PDCCH candidates of the linked search spaces. That is, when a first DCI is transmitted in the linked PDCCH candidates of some of the linked search spaces and a second DCI is transmitted in the linked PDCCH candidates of the other part of the linked search spaces, the first DCI and the second DCI must not be different. From the perspective of the terminal, when two or more search spaces are linked, the terminal can expect that the same DCI is always transmitted in the linked PDCCH candidates of the linked search spaces. That is, when the terminal receives a first DCI in the linked PDCCH candidates of some of the linked search spaces and receives a second DCI in the linked PDCCH candidates of the other part of the linked search spaces, the first DCI and the second DCI can be expected not to be different. In other words, if the first DCI and the second DCI are different, the terminal can determine it as an error case.

[0324] Under the assumption of the above operation of the base station and the terminal, the terminal can receive linked PDCCH candidates of the linked search space in which the same DCI is transmitted in the following manner.

[0325] As a first receiving method, the terminal may receive PDCCH candidates in some or one of the linked search spaces independently or separately. That is, the terminal is configured to repeatedly transmit the same DCI in the linked PDCCH candidates in the linked search space, but the terminal may blindly decode the PDCCH candidates in some or one of the search spaces to receive the DCI. In this case, when blindly decoding the PDCCH candidates in some or one of the search spaces, the PDCCH candidates in the some or one of the search spaces may be used without considering the linked PDCCH candidates in the other linked search spaces. Since blind decoding is performed separately for some or one of the search spaces in this way, it can be expressed as independent or separate. For convenience, this method is called separate PDCCH decoding.

[0326] In the individual PDCCH decoding, the terminal may have multiple PDCCH reception opportunities using different search spaces, and when the multiple PDCCH reception opportunities experience different channel environments, the probability of successful reception of the PDCCH may be increased. For example, when the channel environment of some of the linked search spaces is poor (e.g., when interference is high in the band / time in which the search space is transmitted, the TRP in which the search space is transmitted is blocked and the received SNR is low), the terminal may successfully receive the PDCCH in a search space with a good channel environment among the remaining search spaces. In general, the individual PDCCH decoding may be suitable when the linked search spaces are transmitted in different channel environments.

[0327] As a second receiving method, the terminal may cooperatively or jointly receive the linked PDCCH candidates in the linked search space. That is, since the terminal is configured to repeatedly transmit the same DCI in the linked PDCCH candidates in the linked search space, the terminal may soft-combining and blindly decode the decision values ​​(e.g., a log-likelihood ratio (LLR) value or a decision value similar thereto used in a decoding process) of the linked PDCCH candidates in the linked search space to receive the DCI. In this case, the terminal may be expressed as cooperative or joint since it performs blind decoding using the linked PDCCH candidates in all the linked search spaces. For convenience, this method is called joint PDCCH decoding. For reference, the base station always repeatedly transmits the same DCI in the linked PDCCH candidates in the linked search space, so that the terminal can perform joint PDCCH decoding. In joint PDCCH decoding, since the terminal receives the same DCI multiple times, it is possible to obtain SNR gain (or channel code gain) due to multiple repetitions in addition to the gain due to different channel environments provided by individual PDCCH decoding.

[0328] The terminal may perform PDCCH blind decoding by selectively using one of the individual PDCCH decoding (e.g., a first receiving method) and the joint PDCCH decoding (e.g., a second receiving method). The terminal may also perform PDCCH blind decoding by using both the individual PDCCH decoding and the joint PDCCH decoding. This is determined according to the implementation of the terminal, and thus the base station cannot force the terminal to perform PDCCH blind decoding in a specific method or to perform PDCCH blind decoding using both methods. In other words, the base station configures that the same DCI is repeatedly transmitted in linked PDCCH candidates in a linked search space, but the terminal may perform PDCCH blind decoding by using a part or the whole of the linked search space, and the base station may not know which PDCCH blind decoding method the terminal uses.

[0329] An object of the present disclosure is to resolve the misunderstanding between the base station and the terminal caused by the ambiguity of the PDCCH blind decoding method used by the terminal.

[0330] In the description of this disclosure, the operation of the terminal is described in a situation where two search spaces (e.g., search space 1 and search space 2) are linked, but this may be extended to a situation where more than two search spaces are linked.

[0331] <First embodiment: PDSCH rate matching method depending on whether PDCCH reception (monitoring) is possible>

[0332] FIG. 11 illustrates an example of PDSCH rate matching taking into consideration whether or not PDCCH reception is possible according to an embodiment of the present disclosure.

[0333] Referring to FIG. 11, when the base station and the terminal transmit and receive the PDSCH, the resource on which the PDCCH is transmitted (or received) may be assumed to be a resource unavailable for the PDSCH. Here, the resource of the received PDCCH may include linked PDCCH candidates. For example, in FIG. 11, the terminal may receive a configuration in which the search space 1 1100 and the search space 2 1105 are linked, and the PDCCH candidate 1110, which is an aggregation level of 16 of the search space 1 1100, and the PDCCH candidate 1115, which is an aggregation level of 16 of the search space 2 1105, are linked. That is, the PDCCH candidate 1110, which is an aggregation level of 16 of the search space 1 1100, and the PDCCH candidate 1115, which is an aggregation level of 16 of the search space 2 1105, are configured to receive the same DCI. If a terminal receives (monitors) two linked PDCCH candidates and receives DCI scheduling a PDSCH on the two PDCCH candidates, the terminal can assume that the time-frequency resources corresponding to both PDCCH candidates are unavailable for the PDSCH.

[0334] Some of the linked search spaces or some PDCCH candidates in the search spaces may not be used (monitored) for PDCCH reception due to a specific reason. The terminal may not perform blind decoding for PDCCH candidates that cannot be used (monitored) for PDCCH reception. By not performing blind decoding in this way, the terminal's power consumption is reduced, and the unused blind decoding can be used to receive (monitor) other PDCCH candidates.

[0335] For example, PDCCH candidates that overlap with time-frequency resources in at least the following cases (eg, first case, second case, or third case) may be unavailable for PDCCH reception (monitoring).

[0336] In the first case, a PDCCH candidate overlapping with a time-frequency resource used for an SSB (SS / PBCH block) cannot be used for PDCCH reception. The SSB can be used as information on the initial cell access of the terminal and the quasi-co-located (QCL) of the terminal, and therefore the base station must periodically transmit the SSB (SS / PBCH block) in a specified time-frequency resource. Therefore, downlink signals (including PDCCH) cannot be transmitted at a position overlapping with the time-frequency resource position used for the SSB. For reference, the time-frequency position of the SSB may be set in a system information block received during the terminal's access to a cell, or may be set during the RRC setup process.

[0337] In a second case, a PDCCH candidate overlapping with a rate matching resource set by a base station is unavailable for PDCCH reception. The rate matching resource may include at least one of RateMatchPattern, lte-CRS-ToMatchAround, LTE-CRS-PatternList-r16, or availableRB-SetsPerCell. Here, RateMatchPattern is a rate matching resource in units of RB (resource block) set by a base station to a terminal, lte-CRS-ToMatchAround or LTE-CRS-PatternList-r16 is a rate matching resource in units of RE (resource element), and availableRB-SetsPerCell is a rate matching resource in units of RB-set (a set of RBs). When lte-CRS-ToMatchAround or LTE-CRS-PatternList-r16 is configured as a higher layer signal, PDCCH candidates overlapping with time-frequency resources corresponding to lte-CRS-ToMatchAround or LTE-CRS-PatternList-r16 are always unavailable for PDCCH reception. RateMatchPattern is configured as a higher layer signal, and the availability of the RateMatchPattern may be further indicated by a DCI format (e.g., DCI format 1_1, DCI format 1_2) for scheduling a PDSCH. If the availability of the RateMatchPattern is not indicated by the DCI format for scheduling a PDSCH, PDCCH candidates overlapping with time-frequency resources corresponding to the RateMatchPattern are unavailable for PDCCH reception. availableRB-SetsPerCell is configured as a higher layer signal, and the available RB sets may be indicated by DCI format 2_0, which indicates the slot format.

[0338] In a third case, PDCCH candidates overlapping with some symbols in the symbol direction cannot be used for PDCCH reception. For example, a symbol set as an uplink symbol, indicated as an uplink symbol, or a symbol with an uplink signal or channel scheduled is a symbol used for uplink transmission, so that PDCCH candidates overlapping with the symbol cannot be used for PDCCH reception. Here, the set uplink symbol may be a symbol set as an uplink by tdd-UL-DL-ConfigurationCommon in a system information block (SIB) received during a cell connection process or by tdd-UL-DL-ConfigurationDedicated in an RRC signal. The indicated uplink symbol may be an uplink symbol indicated by DCI format 2_0 indicating a slot format. The symbol with an uplink signal or channel scheduled may be a symbol with PUSCH, SRS, PUCCH, etc. scheduled in DCI format 0_0 / 0_1 / 0_2 / 1_0 / 1_1 / 1_2. In addition, the symbol on which the uplink signal or channel is scheduled may be a symbol on which a periodic transmission signal and channel configured as a higher layer is scheduled, such as a configured grant PUSCH, a periodic SRS, or a PUCCH for transmitting HARQ-ACK of an SPS PDSCH.

[0339] The time-frequency resource in which PDCCH reception (monitoring) is not possible according to the first, second, or third case described above may be expressed as a reserved resource, although such expressions do not limit the technical scope of the present disclosure.

[0340] When some of the linked search spaces or some PDCCH candidates of the search spaces are unavailable for the terminal's PDCCH reception due to a specific reason, the PDCCH candidates linked to the PDCCH candidates may be used for PDCCH reception. For example, when search space 1 and search space 2 are linked and some of the search spaces or some PDCCH candidates of search space 1 are unavailable for PDCCH reception due to the above-mentioned cases (e.g., first case, second case, or third case), i.e., when they overlap with reserved resources, the terminal can receive the PDCCH from the PDCCH candidate of the linked search space 2. Here, the terminal can successfully receive DCI from one PDCCH candidate by the above-mentioned individual PDCCH decoding or joint PDCCH decoding.

[0341] It may be assumed that the received DCI schedules a PDSCH, and the time-frequency resource region of the scheduled PDSCH overlaps with the linked PDCCH. In this case, the base station and the terminal must determine which time-frequency resources of the PDSCH are unavailable for the PDSCH in order to successfully transmit and receive the PDSCH. Then, they must perform rate matching based on the resources available for the PDSCH. Hereinafter, a method for the terminal to determine available resources for receiving the PDSCH will be disclosed.

[0342] [Method 1-1] PDSCH rate matching method that does not consider whether each search space can be received (monitored)

[0343] The terminal may determine a PDSCH rate matching method regardless of whether the PDCCH candidate is received (monitored). Specifically, when at least one PDCCH candidate among the linked PDCCH candidates is a receivable PDCCH candidate, the terminal may receive a DCI format for scheduling a PDSCH in the receivable PDCCH candidate. The terminal may determine that time-frequency resources corresponding to the receivable PDCCH candidate and all PDCCH candidates linked to the receivable PDCCH candidate are unavailable resources for the PDSCH. That is, the terminal may determine that time-frequency resources of the linked PDCCH candidate are unavailable resources for the PDSCH even if the linked PDCCH candidate corresponds to a reserved resource (e.g., the first case, the second case, or the third case) and is not used for PDCCH reception (monitoring).

[0344] 12 illustrates an example of a method for rate matching of a PDSCH when a PDCCH candidate overlaps with a reserved resource according to an embodiment of the present disclosure. More specifically, FIG. 12 illustrates the above-mentioned method 1-1.

[0345] 12, a terminal may be configured to link Search space 1 1200 and Search space 2 1205, and to link PDCCH candidate 1210, which is an aggregation level 16 of Search space 1 1200, and PDCCH candidate 1215, which is an aggregation level 16 of Search space 2 1205. That is, a terminal may be configured to receive the same DCI from PDCCH candidate 1210, which is an aggregation level 16 of Search space 1 1200, and PDCCH candidate 1215, which is an aggregation level 16 of Search space 2 1205. In this case, some resources of the PDCCH candidates of Search space 1 1200 overlap with time-frequency resources of reserved resources (e.g., first case, second case, or third case) 1250. Therefore, the terminal does not receive (monitor) the PDCCH in PDCCH candidate 1210 in search space 1 1200 , but can receive (monitor) the PDCCH in PDCCH candidate 1215 in search space 2 1205 .

[0346] According to method 1-1, when the terminal receives DCI scheduling a PDSCH in a PDCCH candidate 1215 of search space 2 1205, time-frequency resources corresponding to a PDCCH candidate 1210 of search space 1 1200 and a PDCCH candidate 1215 of search space 2 1205 may be included in time-frequency resources unavailable for the PDSCH. That is, if the time-frequency resources in which the PDSCH is scheduled overlap with the time-frequency resources of a PDCCH candidate 1210 of search space 1 1200 and a PDCCH candidate 1215 of search space 2 1205, the overlapping resources 1230 are unavailable for the PDSCH.

[0347] By making the determination as in method 1-1, the terminal does not need to determine whether each PDCCH candidate can be used (monitored), which is advantageous in terms of implementation. However, since the terminal knows that the linked PDCCH candidate is not used, the terminal may not use the time-frequency resource overlapping with the PDCCH candidate even though it can be used for the PDSCH, which may lead to resource loss. For example, in FIG. 12, the terminal does not use the PDCCH candidate 1210 that is not received (monitored) in search space 1 1200 for the PDSCH, which causes resource loss.

[0348] [Method 1-2] PDSCH rate matching method depending on whether or not reception (monitoring) is possible for each search space

[0349] The terminal may determine a PDSCH rate matching method according to whether the PDCCH candidate can be received (monitored). Specifically, when at least one PDCCH candidate among the linked PDCCH candidates is a receivable PDCCH candidate, the terminal may receive a DCI format for scheduling a PDSCH in the receivable PDCCH candidate. The terminal may determine whether the PDCCH candidate and the linked PDCCH candidate can be received (monitored). If the linked PDCCH candidate is a receivable candidate, the terminal may determine that a time-frequency resource corresponding to the linked PDCCH candidate cannot be used for a PDSCH. If the linked PDCCH candidate is a non-receivable candidate, the terminal may determine that a time-frequency resource corresponding to the linked PDCCH can be used for a PDSCH.

[0350] 13 illustrates an example of a method for determining PDSCH rate matching according to whether or not a PDCCH candidate for each search space is received according to an embodiment of the present disclosure. More specifically, FIG. 13 illustrates the above-mentioned method 1-2.

[0351] 13, the base station may configure the terminal such that Search space 1 1300 and Search space 2 1305 are linked, and that a PDCCH candidate 1310 of Search space 1 having an aggregation level of 16 is linked to a PDCCH candidate 1315 of Search space 2 having an aggregation level of 16. That is, the terminal may be configured to receive the same DCI from the PDCCH candidate of Search space 1 having an aggregation level of 16 and the PDCCH candidate of Search space 2 having an aggregation level of 16. In addition, some resources of the PDCCH candidates of Search space 1 overlap with the time-frequency resources of the reserved resources (e.g., first case, second case, or third case) 1350. Therefore, the terminal does not receive (monitor) the PDCCH candidates of Search space 1, but can receive (monitor) the PDCCH candidates of Search space 2.

[0352] According to method 1-2, when the terminal receives DCI scheduling a PDSCH from a PDCCH candidate in search space 2, time-frequency resources 1330 corresponding to the PDCCH candidate in search space 2 may be included in the time-frequency resources unusable for the PDSCH. However, since the terminal does not receive (monitor) a PDCCH from the PDCCH candidate in search space 1, the time-frequency resources corresponding to the PDCCH candidate can be used for the PDSCH.

[0353] By making the determination in method 1-2, resource loss can be reduced compared to method 1-1. However, the UE must determine whether to receive (monitor) the PDCCH every time for rate matching of the PDSCH, which may increase the implementation complexity of the UE.

[0354] [Method 1-2-1] The reserved resources include only signals and channels configured as higher layers (DCI information is ignored)

[0355] In the above-mentioned method 1-2, the reserved resources may include all of the first, second, and third cases. However, the reserved resources may include only some of the cases. As in method 1-2-1, the reserved resources may include only resources configured as a higher layer. More specifically, the first case is configured as a higher layer signal (i.e., SIB and dedicated RRC signal), so it may be included in the reserved resources of method 1-2. In the second case, LTE-CRS-ToMatchAround or LTE-CRS-PatternList-r16 is configured as a higher layer, so it may be included in the reserved resources. In the second case, RateMatchPattern may be configured as a higher layer and additionally indicated by DCI. If the RateMatchPattern is not additionally indicated by DCI, the RateMatchPattern may be included in the reserved resources. If the RateMatchPattern is additionally indicated by DCI, the RateMatchPattern may not be included in the reserved resources. In the second case, availableRB-SetsPerCell is indicated by DCI format 2_0, so the availableRB-SetsPerCell may not be included in the reserved resources. In the third case, the configured uplink symbols are configured as a higher layer, so they may be included in the reserved resources. Also, among the symbols in which uplink signals or channels are scheduled, symbols in which periodic transmission signals and channels such as Configured grant PUSCH, periodic SRS, and PUCCH transmitting HARQ-ACK of SPS PDSCH set as a higher layer are scheduled may be included in the reserved resources. However, the indicated uplink symbols or uplink signals and channels scheduled in the DCI format may not be included in the reserved resources.

[0356] As in method 1-2-1, the reserved resources include only the time-frequency resources of the signals or channels configured as higher layers, so the terminal can have two advantages as follows: First, the reserved resources are determined only by the higher layer signals, so the reserved resources do not change midway. Therefore, the terminal can determine the reserved resources with low complexity.

[0357] Secondly, when the reserved resources include resources indicated by DCI, the reserved resources may change depending on the DCI reception, and when the reserved resources change, the availability of receiving (monitoring) PDCCH candidates may change, which may affect the rate matching of PDSCH. Therefore, when the reserved resources include resources indicated by DCI, misunderstanding may occur in the rate matching of PDSCH between the base station and the terminal. However, since the reserved resources include only signals or channels set as a higher layer, such misunderstanding can be prevented.

[0358] [Method 1-2-2] The reserved resources include signals and channels set by the higher layer and signals and channels indicated by DCI.

[0359] In the above-mentioned method 1-2-1, the reserved resources include only signals and channels set as higher layers, and do not include signals and channels indicated by DCI. However, some signals and channels indicated by DCI may be included in the reserved resources. Here, we will describe signals and channels that may be included in the reserved resources among the signals and channels indicated by DCI.

[0360] As a first example, all signals and channels indicated by the DCI in the above-mentioned first, second, and third cases may be included in the reserved resources, i.e., the reserved resources include all signals and channels corresponding to the first, second, and third cases.

[0361] As a second example, even if the RateMatchPattern in the second case is indicated by DCI, the RateMatchPattern may be included in the reserved resources by DCI. That is, when the DCI indicates the RateMatchPattern as a resource unavailable for PDSCH, the RateMatchPattern may be included in the reserved resources. Even if the RateMatchPattern indicated by DCI is included in the reserved resources in this way, since the DCI is a DCI that schedules PDSCH, there is no misunderstanding in the rate matching of PDSCH between the base station and the terminal.

[0362] As a third example, the uplink symbols and uplink channels and signals indicated by the DCI in the third case may be included in the reserved resources. Here, the reason why only the uplink is selectively included is that the base station uses the region as an uplink and cannot use it for downlink reception such as PDCCH reception and PDSCH reception. Therefore, even if the uplink symbols and uplink channels and signals indicated by the DCI are included in the reserved resources, PDSCH reception is not possible with these symbols, so there is no misunderstanding about the PDSCH rate between the terminal and the base station.

[0363] As a fourth example, in the second or third case, the channel and signal indicated by the DCI received in the common search space may be included in the reserved resource. However, the channel and signal indicated by the DCI received in the UE-specific search space may not be included in the reserved resource. This is because the case of DCI received in the common search space may have higher reliability.

[0364] As a fifth example, in the second or third case, the channels and signals indicated by the DCI received in the UE-specific search space may be included in the reserved resources. However, the channels and signals indicated by the DCI received in the common search space may not be included in the reserved resources. This is because the UE-specific search space allows for a QCL setting and an aggregation level setting suitable for the UE, and therefore may have higher reliability.

[0365] The base station may configure information about reserved resources in the terminal. The information about reserved resources may include information about signals and channels included in the reserved resources. For example, in order to include only some of the channels and signals indicated by the DCI in the reserved resources, the base station may configure information about some of the channels and signals indicated by the DCI in the terminal.

[0366] [Method 1-3] PDSCH rate matching method when at least one of the REs in which the wideband RS of the CORESET to which the linked PDCCH belongs is received overlaps with a reserved resource

[0367] The terminal may be configured with a wideband reference signal (RS) for a specific CORESET. In this case, the terminal may assume that all REs corresponding to RSs of the CORESET are transmitted with the same precoder. Thus, the terminal may perform channel estimation of the entire CORESET using the RE. If the wideband RS is not configured, the terminal may assume the same precoder only in REs corresponding to RSs in a resource element group (REG) bundle of the CORESET.

[0368] If a wideband RS of a CORESET is configured in a terminal, and an RE corresponding to the RS overlaps with a reserved resource, the terminal must determine whether or not PDCCH reception (monitoring) is possible in the CORESET. In the above-mentioned methods 1-1 and 1-2, the time-frequency resource of a PDCCH candidate overlaps with a reserved resource, so the PDCCH candidate is clearly unavailable for PDCCH reception (monitoring). However, in this case, the PDCCH candidate does not overlap with the reserved resource, but a part of the RE corresponding to the RS of the CORESET to which the PDCCH candidate belongs overlaps with the reserved resource, so the terminal can perform channel estimation based on the non-overlapping RE and receive (monitor) the PDCCH candidate.

[0369] As a first example, when a wideband RS of a CORESET is configured in a terminal, if an RE corresponding to the RS overlaps with a reserved resource, the terminal can determine that PDCCH reception (monitoring) is not possible in the CORESET. Also, since it has been determined that reception is not possible, the PDCCH candidate resource can be used for PDSCH transmission.

[0370] As a second example, when a wideband RS of a CORESET is configured in a terminal, if an RE corresponding to the RS overlaps with a reserved resource, the terminal may determine that PDCCH reception (monitoring) is possible in the CORESET, and since it is determined that reception is possible, the PDCCH candidate resource cannot be used for PDSCH transmission.

[0371] If a wideband RS is configured in a first CORESET to which some search spaces belong among linked search spaces configured in the terminal, but a wideband RS is not configured in a second CORESET to which the remaining search spaces belong, the terminal must determine resources available for PDSCH in the first CORESET or the second CORESET. Based on the following first to fourth examples, a method for the terminal to determine resources available for PDSCH in the first CORESET or the second CORESET is proposed.

[0372] As a first example, when the terminal successfully receives DCI for scheduling a PDSCH in a PDCCH candidate in a search space associated with a first CORESET among linked search spaces, the terminal may determine that a resource corresponding to the PDCCH candidate in the first CORESET and an RE corresponding to an RS in the first CORESET are unavailable resources for the PDSCH. The terminal may also determine that a resource corresponding to a PDCCH candidate in a second CORESET linked with the PDCCH candidate is unavailable resources for the PDSCH. However, the terminal may determine that an RE corresponding to an RS in the second CORESET is available for the PDSCH. This is because a wideband RS is not configured in the second CORESET. The first example is also applicable to a case where the terminal receives DCI for scheduling a PDSCH in a PDCCH candidate in a search space associated with a second CORESET among linked search spaces.

[0373] As a second example, when the terminal successfully receives DCI for scheduling a PDSCH in a PDCCH candidate in a search space associated with a first CORESET among linked search spaces, the terminal may determine that a resource corresponding to a PDCCH candidate in the first CORESET and an RE corresponding to an RS in the first CORESET are resources that cannot be used for a PDSCH. Also, the terminal may determine that a resource corresponding to a PDCCH candidate in a second CORESET linked with the PDCCH candidate and an RE corresponding to an RS in the second CORESET are resources that cannot be used for a PDSCH. In the second example, when a wideband RS is configured in one CORESET, the terminal may determine resources that are not used for a PDSCH in a CORESET in which the wideband RS is not configured, similarly to when a wideband RS is configured. The second example can be applied to a case where a DCI for scheduling a PDSCH is received in a PDCCH candidate in a search space associated with a second CORESET among linked search spaces.

[0374] As a third example, when the terminal successfully receives DCI scheduling a PDSCH from a PDCCH candidate in a search space associated with a second CORESET among the linked search spaces, the terminal may determine that a resource corresponding to the PDCCH candidate of the second CORESET linked with the PDCCH candidate is an unavailable resource for the PDSCH. In addition, when all PDCCH candidates overlap with reserved resources in a search space associated with a first CORESET, the terminal may determine that a resource corresponding to the PDCCH candidate of the first CORESET and an RE corresponding to an RS of the first CORESET are available resources for the PDSCH. That is, since all PDCCH candidates overlap with reserved resources in a search space associated with a first CORESET, all PDCCH candidates are unreceivable in the search space associated with the first CORESET. Since the terminal cannot receive the PDCCH candidate, the terminal may use the time-frequency resource of the PDCCH candidate for the PDSCH.

[0375] As a fourth example, when the terminal successfully receives DCI for scheduling a PDSCH in a PDCCH candidate in a search space associated with a second CORESET among the linked search spaces, the terminal may determine a resource corresponding to the PDCCH candidate in the second CORESET linked with the PDCCH candidate as a resource unavailable for the PDSCH. In addition, when all PDCCH candidates in a search space associated with a first CORESET overlap with reserved resources, the terminal may determine a resource corresponding to the PDCCH candidate in the first CORESET and an RE corresponding to an RS in the first CORESET as a resource unavailable for the PDSCH. That is, since all PDCCH candidates in a search space associated with a first CORESET overlap with reserved resources, all PDCCH candidates in the search space associated with the first CORESET are unreceivable, but the terminal does not need to use the time-frequency resource of the PDCCH candidate for the PDSCH.

[0376] The third and fourth examples are also applicable to the case where a wideband RS is configured in the second CORESET.

[0377] <Second embodiment: Method for distinguishing between aggregation level 8 and aggregation level 16 and rate matching using the same>

[0378] In the above, it is assumed that when a terminal receives DCI that schedules a PDSCH, the time-frequency resource used to receive the PDCCH including the DCI is not used to receive the PDSCH. This is based on the assumption that the terminal knows the time-frequency resource used to receive the PDCCH. However, a case may occur in which the terminal successfully receives DCI in a specific situation but is unable to determine the time-frequency resource used to receive the PDCCH including the DCI. In the following description, this situation is referred to as an ambiguity situation.

[0379] 14A to 14D show ambiguous situations for AL determination according to an embodiment.

[0380] 14A to 14D, a base station may configure a CORESET 1410 having a length of one symbol to a terminal, and the CORESET may be configured with non-interleaved mapping. The base station may then configure a search space 1410 belonging to the CORESET to the terminal. The search space may include at least one PDCCH candidate 1405 having an aggregation level of 8 and at least one PDCCH candidate 1400 having an aggregation level of 16. That is, the terminal must perform blind decoding of at least one PDCCH candidate having an aggregation level of 8 and at least one PDCCH candidate having an aggregation level of 16 in the search space.

[0381] 14A, a base station may transmit DCI for scheduling a PDSCH with a PDCCH candidate 1400 having an aggregation level of 16. In this case, the PDCCH candidate includes a total of 16 CCEs, and time-frequency resources corresponding to the 16 CCEs are not used for the PDSCH. That is, when the base station generates and transmits the PDSCH, the base station does not use the time-frequency resource region corresponding to the 16 CCEs for PDSCH transmission.

[0382] Referring to FIG. 14B, the terminal may perform blind decoding of a PDCCH candidate 1405 having an aggregation level of 8 and a PDCCH candidate 1400 having an aggregation level of 16 in the search space. Here, if the starting CCE index of the PDCCH candidate having an aggregation level of 8 is the same as the starting CCE index of the PDCCH candidate having an aggregation level of 16, the terminal may receive DCI in a PDCCH having an aggregation level of 8. This is because, when the signal-noise ratio of the eight CCEs corresponding to the PDCCH candidate having an aggregation level of 8 is excellent or when the interference of the remaining eight CCEs is strong, the base station transmits DCI in a PDCCH candidate having an aggregation level of 16, but there is a possibility that the DCI is decoded in the PDCCH candidate having the aggregation level of 8. In this case, since the terminal receives DCI for scheduling a PDSCH in a PDCCH candidate having an aggregation level of 8, the terminal may assume that the eight CCEs corresponding to the PDCCH candidate having the aggregation level of 8 are not used for receiving the PDSCH. Therefore, the terminal receives the PDSCH in the remaining resource regions except for the time-frequency resource regions of the eight CCEs. In this case, the PDSCH transmitted by the base station and the PDSCH received by the terminal are transmitted / received in different resource regions, so the terminal cannot successfully receive the PDSCH.

[0383] 14C, the base station may transmit DCI for scheduling a PDSCH with a PDCCH candidate 1405 having an aggregation level of 8. In this case, the PDCCH candidate includes a total of 8 CCEs, and time-frequency resources corresponding to the 8 CCEs are not used for the PDSCH. That is, when the base station generates and transmits the PDSCH, the base station does not use the time-frequency resource region corresponding to the 8 CCEs for PDSCH transmission.

[0384] Referring to FIG. 14D, the terminal may perform blind decoding of a PDCCH candidate 1405 having an aggregation level of 8 and a PDCCH candidate 1400 having an aggregation level of 16 in the search space. Here, if the starting CCE index of the PDCCH candidate having an aggregation level of 8 and the starting CCE index of the PDCCH candidate having an aggregation level of 16 are the same, the terminal may receive DCI in a PDCCH having an aggregation level of 16. This is because, when the signal-noise ratio of 8 CCEs corresponding to the PDCCH candidate having an aggregation level of 8 is excellent and the signal-noise ratio of the remaining 8 CCEs is low, the base station transmits DCI in the PDCCH candidate having an aggregation level of 8, but there is a possibility that the DCI is decoded in the PDCCH candidate having the aggregation level of 16. In this case, since the terminal receives DCI for scheduling a PDSCH in a PDCCH candidate having an aggregation level of 16, it may be assumed that the 16 CCEs corresponding to the PDCCH candidate having the aggregation level of 16 are not used for receiving the PDSCH. Therefore, the PDSCH is received in the remaining resource regions excluding the time-frequency resource regions of the 16 CCEs. In this case, the PDSCH transmitted by the base station and the PDSCH received by the terminal are transmitted / received in different resource regions, so the terminal cannot successfully receive the PDSCH.

[0385] The above-mentioned FIGS. 14A-14D are merely examples, which can obviously be extended to other ambiguous situations.

[0386] In this way, the PDCCH candidates to which the base station transmits DCI may differ from the PDCCH candidates to which the terminal receives DCI. This may affect the PDSCH rate matching of the terminal. Therefore, 3GPP Rel-15 defines the following terminal operation.

[0387] 3GPP Rel-15 terminal operation: When CORESET is configured as 1 symbol, non-interleaving mapping, and the terminal monitors aggregation level 8 PDCCH candidates and aggregation level 16 PDCCH candidates starting from the same CCE index, if the terminal receives DCI scheduling a PDSCH on an aggregation level 8 PDCCH candidate, the terminal does not use the time-frequency resources corresponding to the aggregation level 16 PDCCH candidate for PDSCH reception.

[0388] As described above, the 3GPP Rel-15 terminal operation assumes that the terminal receives at aggregation level 16, which is the larger aggregation level of the two, when there is ambiguity between aggregation level 8 and aggregation level 16. If this assumption is made, the time-frequency resources of PDCCH candidates of aggregation level 16 cannot be used for the PDSCH, resulting in resource loss, but misunderstandings about PDSCH rate matching between the base station and the terminal can be prevented.

[0389] 15A and 15B illustrate an example of a rate matching method for PDSCH in the case of aggregation level decision ambiguity according to one embodiment of the present disclosure.

[0390] 15A and 15B, a terminal monitors an aggregation level (AL) 8 PDCCH candidate 1505 and an aggregation level 16 PDCCH candidate 1510 that start from the same CCE 1520 in a search space 1500. In the example shown in FIG.

[0391] In FIG. 15A, when a terminal receives DCI scheduling a PDSCH with a PDCCH candidate 1505 of aggregation level (AL) 8, the terminal does not use time-frequency resources 1530 corresponding to a PDCCH of aggregation level 16 for PDSCH reception.

[0392] In FIG. 15B, when a terminal receives DCI scheduling a PDSCH in a PDCCH candidate 1510 of aggregation level (AL) 16, the terminal does not use the time-frequency resource 1535 corresponding to the PDCCH of aggregation level 16 for PDSCH reception.

[0393] Based on Figures 15A and 15B, even if the terminal receives DCI scheduling a PDSCH at a PDCCH candidate of any aggregation level (AL), the same resources are not used for PDSCH transmission, so misunderstandings regarding PDSCH rate-matching between the base station and the terminal can be prevented.

[0394] FIG. 16 is an example illustrating a situation in which some of the PDCCH candidates are not monitored according to one embodiment of the present disclosure.

[0395] 16, the terminal is configured to monitor two PDCCH candidates 1605 and 1610, but one of the PDCCH candidates 1610 is not received (monitored) because it overlaps with a reserved resource 1650. In the example of FIG. 16, the PDCCH candidate 1610 corresponding to aggregation level (AL) 16 cannot be received (monitored) because it overlaps with a reserved resource 1650. In this situation, the terminal can receive DCI scheduling a PDSCH with the PDCCH candidate 1605 of aggregation level 8.

[0396] In the above description of Figures 15A and 15B, ambiguity may occur between aggregation level 8 and aggregation level 16, and therefore the terminal assumes aggregation level 16. However, in Figure 16, PDCCH candidates of aggregation level 16 are not received (monitored), so no ambiguity occurs between aggregation level 8 and aggregation level 16 any more. As a result, the terminal can receive the PDSCH assuming aggregation level 8. That is, when receiving the PDSCH, the terminal does not need to use time-frequency resources 1630 corresponding to aggregation level 8 for PDSCH reception.

[0397] 17 to 20 illustrate an example of a rate matching method for a PDSCH in consideration of PDCCH repetitive transmission, ambiguity in aggregation level determination, and reserved resources according to an embodiment of the present disclosure.

[0398] 17 to 20, the terminal may be configured with two linked search spaces (e.g., search space 1 and search space 2), and at least one PDCCH candidate of aggregation level 8 and at least one PDCCH candidate of aggregation level 16 may be configured in each search space. The PDCCH candidate of aggregation level 8 and the PDCCH candidate of aggregation level 16 may start from the same CCE in both search spaces. In this case, even if the terminal performs individual PDCCH decoding, the terminal may have aggregation level decision ambiguity in search space 1 and may have aggregation level decision ambiguity in search space 2. Moreover, even if the terminal performs joint PDCCH decoding, aggregation level decision ambiguity may occur in both search spaces. For reference, two PDCCH candidates of aggregation level 8 in both linked search spaces always transmit the same DCI, and two PDCCHs of aggregation level 16 always transmit the same DCI.

[0399] A preferred operation of the terminal according to one embodiment of the present disclosure may be as follows.

[0400] When at least one of two linked search spaces monitored by the terminal satisfies <condition>, when the terminal receives DCI scheduling a PDSCH with a PDCCH candidate of aggregation level 8 in one or two of the linked search spaces, the terminal does not use time-frequency resources corresponding to PDCCH candidates of aggregation level 16 in both search spaces for PDSCH reception.

[0401] Here, the <conditions> are as follows:

[0402] <Condition>: 1 symbol, non-interleaving mapping CORESET is set, and includes an aggregation level 8 PDCCH candidate and an aggregation level 16 PDCCH candidate starting from the same CCE index.

[0403] The condition is one of the conditions under which the terminal cannot determine the received PDCCH candidates. Here, the operation of the terminal according to the condition will be described, but the operation may be performed according to other conditions under which the terminal cannot determine the received PDCCH candidates.

[0404] The terminal behavior proposed in 3GPP Rel-15 for resolving aggregation level ambiguities for one search space can be extended to multiple linked search spaces.

[0405] 17 to 20, a case may be considered in which some PDCCH candidates are not received (monitored) in one of the linked search spaces. The PDCCH candidates of aggregation level 16 in search space 1 overlap with reserved resources and are therefore not received (monitored). Then, the PDCCH candidates of aggregation level 8 in search space 1, the PDCCH candidates of aggregation level 8 in search space 2, and the PDCCH candidates of aggregation level 16 may be received (monitored). In this case, the base station may transmit DCI in one of the following two ways.

[0406] As a first method, the base station may repeatedly transmit DCI on linked PDCCH candidates of aggregation level 8 in two linked search spaces. That is, the base station may repeatedly transmit the same DCI on PDCCH candidates of aggregation level 8 in search space 1 and PDCCH candidates of aggregation level 8 in search space 2.

[0407] As a second method, the base station can transmit DCI on PDCCH candidates of aggregation level 16 in search space 2. That is, the base station transmits DCI on PDCCH candidates of aggregation level 16 in search space 2, but does not need to transmit DCI on PDCCH candidates of linked aggregation level 16 in search space 1 because the PDCCH candidates of linked aggregation level 16 in linked search space 1 overlap with reserved resources.

[0408] The terminal may receive DCI for scheduling PDSCH by blindly decoding PDCCH through an individual PDCCH decoding or joint PDCCH decoding scheme as follows. When the terminal receives DCI for scheduling PDSCH, the unavailable resources for the PDSCH may be determined based on the following method. For reference, the same PDSCH rate matching method can be used here regardless of the PDCCH decoding assumption (individual PDCCH decoding or joint PDCCH decoding) of the terminal. Therefore, the PDCCH decoding assumption of other terminals may be omitted in the following description.

[0409] [Method 2-1] PDSCH rate matching decision in each linked search space

[0410] An embodiment of [Method 2-1] will be described with reference to Figures 17 and 18. The terminal may determine resources unavailable for PDSCH in each of the linked search spaces. More specifically, the terminal may determine an aggregation level based on a PDCCH received in each of the linked search spaces or a configuration of each search space, and may determine resources unavailable for PDSCH based on the aggregation level for each search space.

[0411] With reference to FIG. 17, it may be assumed that the terminal receives PDCCHs 1720 and 1710 of aggregation level 8 in linked search spaces 1700 and 1705. The terminal may determine the aggregation level in each of the two linked search spaces. For example, since a PDCCH candidate 1720 of aggregation level 8 and a PDCCH candidate 1725 of aggregation level 16 that satisfy the above-mentioned <condition> exist in search space 2 1705, the terminal may determine the aggregation level as 16 in search space 2 (the aggregation level 16 is determined as 16 because the aggregation level 16 is a super-set of the aggregation level 8). That is, the terminal may assume that the time-frequency resources corresponding to the PDCCH candidates of aggregation level 16 in search space 2 cannot be used for PDSCH. In search space 1 1700, a PDCCH candidate 1710 of aggregation level 8 and a PDCCH candidate 1715 of aggregation level 16 that satisfy the above-mentioned <condition> do not exist. This is because the PDCCH candidates of the aggregation level 16 in the search space 1 are not received (monitored). Therefore, the received aggregation level, that is, the aggregation level 8, can be assumed in the search space 1. That is, the terminal can assume that the time-frequency resource 1730 corresponding to the PDCCH candidate of the aggregation level 8 in the search space 1 cannot be used for the PDSCH.

[0412] The terminal operation of FIG. 17 above can also be applied when the terminal receives a PDCCH with aggregation level 16 in the linked search space. That is, the terminal receives a PDCCH with aggregation level 16 in the linked search space, but since there is ambiguity between aggregation level 8 and aggregation level 16 as described above, the same terminal operation as when a PDCCH with aggregation level 8 is received may be defined.

[0413] When the terminal receives a PDCCH of aggregation level 16 in the linked search space, an operation different from that in FIG. 17 may be defined.

[0414] With reference to FIG. 18, it may be assumed that the terminal receives PDCCHs 1815 and 1825 of aggregation level 16 in linked search spaces 1800 and 1805. The terminal may determine the aggregation level in each of the two linked search spaces. For example, in search space 2 1805, a PDCCH candidate 1820 of aggregation level 8 and a PDCCH candidate 1825 of aggregation level 16 that satisfy the above-mentioned <condition> exist, so the terminal may determine that the search space 2 is at aggregation level 16 (the aggregation level 16 is determined as a super-set or superset of the aggregation level 8). That is, the terminal may assume that the time-frequency resource 1830 corresponding to the PDCCH candidate of aggregation level 16 in search space 2 cannot be used for PDSCH. In search space 1, there are no PDCCH candidates of aggregation level 8 and no PDCCH candidates of aggregation level 16 that satisfy the above-mentioned <condition>. This is because the PDCCH candidate 1815 of the aggregation level 16 of the search space 1 is not received (monitored). Therefore, since there is no PDCCH candidate corresponding to the received aggregation level 16 in the search space 1 1800, the terminal can assume that all time-frequency resources in the search space 1 are available for the PDSCH.

[0415] [Method 2-2] When there is ambiguity in any one of the linked search spaces, PDSCH rate matching decision is made based on the search space with ambiguity.

[0416] An embodiment of [Method 2-2] will be described with reference to FIG. 19. The terminal may determine resources unavailable for the PDSCH based on the settings of all linked search spaces in which the received PDCCH is transmitted. More specifically, when ambiguity occurs in an aggregation level determination in at least one of all linked search spaces in which the received PDCCH is transmitted, the terminal may determine an aggregation level in the search space in which the ambiguity occurs to determine resources unavailable for the PDSCH, and may determine resources unavailable for the PDSCH in the remaining linked search spaces based on the aggregation level. For example, ambiguity may occur in a search space that satisfies the above-mentioned <Condition>, that is, in a search space in which one symbol, non-interleaving mapping CORESET is set and which includes a PDCCH candidate with an aggregation level of 8 and a PDCCH candidate with an aggregation level of 16 starting from the same CCE index.

[0417] FIG. 19 illustrates a PDSCH rate matching method taking into account PDCCH repeated transmission, ambiguity in AL decision, and reserved resources according to an embodiment of the present disclosure.

[0418] Referring to FIG. 19, the terminal may assume that it has received PDCCHs in two linked search spaces 1900 and 1905. Here, the aggregation level of the received PDCCHs may be either 8 or 16. The terminal may determine whether there is a search space that satisfies the <condition> among the two search spaces. For example, search space 11900 does not satisfy the <condition>, but search space 21905 satisfies the <condition>. According to method 2-2, the terminal may determine the aggregation level in search space 2 where ambiguity occurs in the aggregation level determination. The aggregation level in search space 2 may be assumed to be 16 (aggregation level 16 is determined as aggregation level 16 because it is a super-set of aggregation level 8). That is, the terminal may assume that time-frequency resources corresponding to PDCCH candidates of aggregation level 16 in search space 2 are not used for PDSCH. The aggregation level may be assumed to be the same in the remaining search space 1. Therefore, the terminal can assume that the time-frequency resource 1930 corresponding to the PDCCH candidate of aggregation level 16 in search space 1 is not used for the PDSCH.

[0419] [Method 2-3] If there is ambiguity in any one of the linked search spaces, the PDSCH rate matching decision is made based on the unambiguous search space.

[0420] An embodiment of [Method 2-3] will be described with reference to FIG. 20. The terminal may determine resources unavailable for the PDSCH based on the configuration of all linked search spaces in which the received PDCCH is transmitted. More specifically, when ambiguity occurs in an aggregation level determination in at least one of all linked search spaces in which the received PDCCH is transmitted, the terminal may determine an aggregation level in a search space in which the ambiguity does not occur, determine resources unavailable for the PDSCH, and determine resources unavailable for the PDSCH in the remaining linked search spaces based on the aggregation level. For example, ambiguity may occur in a search space that satisfies the above-mentioned <Condition>, that is, in a search space in which one symbol, non-interleaving mapping CORESET is set, and which includes a PDCCH candidate with aggregation level 8 and a PDCCH candidate with aggregation level 16 starting from the same CCE index.

[0421] FIG. 20 illustrates a PDSCH rate matching method taking into account PDCCH repeated transmission, ambiguity in AL decision, and reserved resources according to an embodiment of the present disclosure.

[0422] Referring to FIG. 20, it may be assumed that a terminal receives PDCCHs in two linked search spaces 2000 and 2005. Here, the aggregation level of the received PDCCHs may be either 8 or 16. The terminal may determine whether there is a search space that satisfies the <condition> among the two search spaces. For example, search space 1 2000 does not satisfy the <condition>, but search space 2 2005 satisfies the <condition>. By using method 2-3, the terminal may determine the aggregation level in search space 1, where no ambiguity occurs in determining the aggregation level.

[0423] If the terminal receives a PDCCH 2010 of aggregation level 8 in search space 1, the terminal may assume the aggregation level 8. That is, in search space 1, the terminal may assume that time-frequency resources of PDCCH candidates 2030 of aggregation level 8 are not used for PDSCH. The terminal may then assume the same aggregation level in the remaining search space 2 2005. That is, the terminal may assume that time-frequency resources of PDCCH candidates 2035 of aggregation level 8 in search space 2 are not used for PDSCH.

[0424] If the terminal cannot receive a PDCCH with an aggregation level of 8 in search space 1, the terminal may assume that no PDCCH candidates with an aggregation level of 8 were transmitted in search space 1. That is, the terminal may use the time-frequency resources of search space 1 for PDSCH. In this case, the terminal must determine the aggregation level in search space 2. In this case, since search space 2 satisfies <condition>, it is preferable to determine the aggregation level as 16 (aggregation level 16 is determined as a super-set of aggregation level 8). That is, the terminal may assume that the time-frequency resources of PDCCH candidates with an aggregation level of 16 in search space 2 are not used for PDSCH.

[0425] Method 2-2 or 2-3 is a method of determining an aggregation level based on one of the linked search spaces and applying the determined aggregation level to the remaining search spaces. Here, one search space may be a search space that satisfies the <condition> in method 2-2 or a search space that does not satisfy the <condition> in method 2-3.

[0426] Alternatively, the one search space may be determined regardless of the <condition>. For example, a search space with the lowest (or highest) search space index or ID (identity) among the linked search spaces may be selected. The terminal may determine an aggregation level based on the search space with the lowest (or highest) search space index or ID (identity) among the linked search spaces, and apply the determined aggregation level to the remaining search spaces.

[0427] As yet another example, the earliest (or latest) search space in time may be selected from among the linked search spaces. The terminal may determine an aggregation level based on the earliest (or latest) search space in time from among the linked search spaces, and apply the determined aggregation level to the remaining search spaces. Once one search space is determined, an aggregation level assumed in the search space may be determined by the above methods of FIGS. 17 to 20.

[0428] In Fig. 17 to Fig. 20, both of the two search spaces satisfy <condition> when there is no reserved resource. Then, one of the two search spaces satisfies <condition> and the other does not satisfy <condition> due to the reserved resource. Next, with reference to Fig. 21 to Fig. 23B, a case where one of the two search spaces satisfies <condition> and the other does not satisfy <condition> even without another reserved resource will be described. For example, as described above, whether or not <condition> is satisfied may be determined depending on whether the search space is set to one symbol, a non-interleaving mapping CORESET, and includes a PDCCH candidate of aggregation level 8 and a PDCCH candidate of aggregation level 16 starting from the same CCE index.

[0429] 21 to 23 are diagrams illustrating rate matching of PDSCH in the case of PDCCH repeated transmission and ambiguity in aggregation level decision according to an embodiment of the present disclosure.

[0430] 21 to 23B, two search spaces, search space 1 and search space 2, linked to a terminal are set. For reference, the two search spaces may belong to different CORESETs, and the different CORESETs may start linked PDCCH candidates at different CCE indexes according to the index (or ID (identity)) of the CORESET. For example, PDCCH candidates at aggregation level 16 in search space 1 and search space 2 may start from CCE index 0. However, PDCCH candidates at aggregation level 8 in search space 2 may start from CCE index 0, while PDCCH candidates at aggregation level 8 in search space 1 may start from CCE index 16. Therefore, the <condition> is satisfied in the case of search space 2, but the <condition> is not satisfied in the case of search space 1. In such a search space setting, resources not used for PDSCH may be determined based on the method described below.

[0431] [Method 2-1] PDSCH rate matching decision in each linked search space

[0432] An embodiment of [Method 2-1] will be described with reference to Figure 21. The terminal may determine resources unavailable for PDSCH in each of the linked search spaces. More specifically, the terminal may determine an aggregation level based on a PDCCH received in each of the linked search spaces or a configuration of each search space, and may determine resources unavailable for PDSCH based on the aggregation level for each search space.

[0433] FIG. 21 illustrates PDSCH rate matching in the case of repeated PDCCH transmission and AL decision ambiguity according to one embodiment of the present disclosure.

[0434] Referring to FIG. 21, it may be assumed that the terminal receives PDCCHs 2110 and 2120 with an aggregation level of 8 in linked search spaces 2100 and 2105. The terminal may determine the aggregation level in each of the two linked search spaces. For example, since a PDCCH candidate 2120 with an aggregation level of 8 and a PDCCH candidate 2125 with an aggregation level of 16 that satisfy the above-mentioned <condition> exist in search space 2 2105, the terminal may determine that the search space 2 is at an aggregation level of 16 (the aggregation level 16 is determined as a super-set of the aggregation level 8). That is, the terminal may assume that a time-frequency resource 2135 corresponding to a PDCCH candidate with an aggregation level of 16 in search space 2 cannot be used for PDSCH. In search space 1 2100, there is no PDCCH candidate 2110 of aggregation level 8 and no PDCCH candidate 2115 of aggregation level 16 that satisfy the above-mentioned <condition>. This is because the PDCCH candidate of aggregation level 16 in search space 1 is not received (monitored). Therefore, in search space 1, the received aggregation level, aggregation level 8, may be assumed. That is, the terminal may assume that the time-frequency resource 2130 corresponding to the PDCCH candidate of aggregation level 8 in search space 1 cannot be used for PDSCH.

[0435] [Method 2-2] When there is ambiguity in any one of the linked search spaces, PDSCH rate matching decision is made based on the search space with ambiguity.

[0436] An embodiment of [Method 2-2] will be described with reference to FIG. 22. The terminal may determine resources unavailable for the PDSCH based on the settings of all linked search spaces in which the received PDCCH is transmitted. More specifically, when ambiguity occurs in determining an aggregation level in at least one search space among all linked search spaces in which the received PDCCH is transmitted, the terminal may determine resources unavailable for the PDSCH by determining an aggregation level in the search space in which the ambiguity occurs, and may determine resources unavailable for the PDSCH in the remaining linked search spaces based on the aggregation level.

[0437] FIG. 22 illustrates PDSCH rate matching in case of repeated PDCCH transmission and AL decision ambiguity according to one embodiment of the present disclosure.

[0438] Referring to FIG. 22, it is assumed that the terminal receives PDCCHs in two linked search spaces 2200 and 2205. Here, the aggregation level of the received PDCCHs may be either 8 or 16. The terminal may determine whether there is a search space that satisfies the above-mentioned <condition> among the two search spaces. For example, search space 1 2200 does not satisfy the <condition>, but search space 2 2205 satisfies the <condition>. According to method 2-2, the terminal may determine the aggregation level in search space 2 where ambiguity occurs in the aggregation level determination. The aggregation level in search space 2 is assumed to be 16 (aggregation level 16 is determined as aggregation level 16 because it is a super-set of aggregation level 8). That is, the terminal may assume that time-frequency resources 2235 corresponding to PDCCH candidates of aggregation level 16 in search space 2 are not used for PDSCH. For reference, the time-frequency resources of PDCCH candidates 2225 of aggregation level 16 in search space 2 2205 may include all time-frequency resources of PDCCH candidates 2220 of aggregation level 8. Therefore, the terminal's assumption that the time-frequency resources corresponding to PDCCH candidates of aggregation level 16 in search space 2 are not used for the PDSCH is the same as the terminal's assumption that the time-frequency resources corresponding to PDCCH candidates of aggregation level 8 and PDCCH candidates of aggregation level 16 in search space 2 are not used for the PDSCH.

[0439] Further, resources not used for PDSCH in the remaining search space 1 2200 can be determined based on the aggregation level. In the search space 2, the aggregation level 16, which is a super-set of the aggregation level 8 and the aggregation level 16, is assumed to be the aggregation level 16. However, in the search space 1, the aggregation level 16 2215 is not a super-set of the aggregation level 8 2210. Therefore, preferably, the terminal may assume that the union 2230 of the time-frequency resources corresponding to the PDCCH candidates 2210 of the aggregation level 8 and the time-frequency resources corresponding to the PDCCH candidates 2215 of the aggregation level 16 in the search space 1 is not used for PDSCH. That is, it may be assumed that not one but two PDCCH candidates are not used for PDSCH in the search space 1.

[0440] [Method 2-3] PDSCH rate matching decision based on unambiguous search space when there is ambiguity in any one of the linked search spaces

[0441] An embodiment of [Method 2-3] will be described with reference to Figures 23A and 23B. The terminal may determine resources unavailable for the PDSCH based on the settings of all linked search spaces in which the received PDCCH is transmitted. More specifically, when ambiguity occurs in determining an aggregation level in at least one search space among all linked search spaces in which the received PDCCH is transmitted, the terminal may determine resources unavailable for the PDSCH by determining an aggregation level in the search space in which no ambiguity occurs, and may determine resources unavailable for the PDSCH in the remaining linked search spaces based on the aggregation level.

[0442] FIG. 23A illustrates PDSCH rate matching in the case of repeated PDCCH transmission and AL decision ambiguity according to one embodiment of the present disclosure.

[0443] Referring to FIG. 23A, the terminal may assume that it has received PDCCHs 2310 and 2320 of aggregation level 8 in two linked search spaces 2300 and 2305. The terminal may determine whether there is a search space that satisfies the above-mentioned <condition> among the two search spaces. For example, search space 1 2300 does not satisfy the <condition>, but search space 2 2305 satisfies the <condition>. According to method 2-3, the terminal may determine the aggregation level in search space 1 where no ambiguity occurs in the aggregation level determination. When the terminal receives PDCCH 2310 of aggregation level 8 in search space 1, the terminal may assume the aggregation level 8. That is, in search space 1, the terminal may assume that the time-frequency resource 2330 of the PDCCH candidate of aggregation level 8 is not used for the PDSCH. The terminal may then assume the same aggregation level in the remaining search space 2. That is, the terminal may assume that the time-frequency resource 2335 of the PDCCH candidate of aggregation level 8 in search space 2 is not used for the PDSCH.

[0444] FIG. 23B illustrates PDSCH rate matching in the case of repeated PDCCH transmission and AL decision ambiguity according to one embodiment of the present disclosure.

[0445] Referring to FIG. 23B, the terminal may assume that it has received PDCCHs 2315 and 2325 of aggregation level 16 in two linked search spaces 2300 and 2305. The terminal may determine whether there is a search space that satisfies the above-mentioned <condition> among the two search spaces. For example, search space 1 2300 does not satisfy the <condition>, but search space 2 2305 satisfies the <condition>. By using method 2-3, the terminal may determine the aggregation level in search space 1 where no ambiguity occurs in the aggregation level determination. If the terminal receives PDCCH 2315 of aggregation level 16 in search space 1, the terminal may assume the aggregation level 16. That is, in search space 1, the terminal may assume that the time-frequency resource 2340 of the PDCCH candidate of aggregation level 16 is not used for the PDSCH. The terminal may then assume the same aggregation level in the remaining search space 2. That is, the terminal may assume that the time-frequency resource 2345 of the PDCCH candidate at aggregation level 16 in search space 2 is not used for the PDSCH.

[0446] 24 to 26 are flowcharts showing a PDSCH rate matching method according to an embodiment of the present disclosure. More specifically, Fig. 24, Fig. 25, and Fig. 26 show flowcharts of method 2-1, method 2-2, and method 2-3, respectively.

[0447] 24, a plurality of search spaces may be set for a terminal from a base station in step 2400. Each of the plurality of search spaces may include at least one PDCCH candidate of aggregation level 8 and at least one PDCCH candidate of aggregation level 16.

[0448] In step 2405, the UE may receive from the base station a linked search space in which the same DCI is repeatedly transmitted (ie, PDCCH repeated transmission) among the plurality of search spaces.

[0449] In step 2410, the UE may receive DCI scheduling a PDSCH in the linked search space.

[0450] In step 2415, the UE may determine an aggregation level of PDCCH candidates for which the DCI is transmitted based on the configuration information of each of the linked search spaces. When determining the aggregation level in each search space, if <condition> is satisfied, the aggregation level may be determined as 16, and if <condition> is not satisfied, the aggregation level may be determined as 8. Also, when determining the aggregation level in one search space, other linked search spaces may not be considered.

[0451] In step 2420, the UE may rate-match and receive the PDSCH based on the aggregation levels determined in each search space.

[0452] 25, a plurality of search spaces may be set for a terminal from a base station in step 2500. Each of the plurality of search spaces may include at least one PDCCH candidate of aggregation level 8 and at least one PDCCH candidate of aggregation level 16.

[0453] In step 2505, the UE may receive from the base station a linked search space in which the same DCI is repeatedly transmitted among the plurality of search spaces.

[0454] In step 2510, the terminal may receive DCI scheduling a PDSCH in the linked search space.

[0455] In step 2515, the terminal may determine a search space that satisfies a <condition> based on configuration information of the linked search space.

[0456] In step 2520, the terminal may determine an aggregation level in the search space that satisfies the <condition>. For example, if the <condition> is satisfied, the terminal may determine the aggregation level as 16.

[0457] In step 2525, the terminal may determine (decide) an aggregation level in the search space that does not satisfy <condition> based on the determined aggregation level. Since the terminal has determined that the aggregation level of the search space that satisfies <condition> is 16, the terminal may determine that the aggregation level in the search space that does not satisfy <condition> is 16. If the aggregation level 16 in the search space that does not satisfy <condition> is not a superset of the aggregation level 8 (i.e., the time-frequency resource of the PDCCH with the aggregation level 16 does not completely include the time-frequency resource of the PDCCH with the aggregation level 8), the terminal may determine that the aggregation levels of the search space that does not satisfy <condition> are 8 and 16.

[0458] In step 2530, the UE may rate-match and receive the PDSCH based on an aggregation level determined in a search space that satisfies the <condition> and an aggregation level determined in a search space that does not satisfy the <condition>. Time-frequency resources of PDCCH candidates of aggregation level 16 in a search space that satisfies the <condition> are not used for the PDSCH, and time-frequency resources of PDCCH candidates of aggregation level 8 and aggregation level 16 in a search space that does not satisfy the <condition> are not used for the PDSCH.

[0459] 26, a plurality of search spaces may be set for a terminal from a base station in step 2600. Each of the plurality of search spaces may include at least one PDCCH candidate of aggregation level 8 and at least one PDCCH candidate of aggregation level 16.

[0460] In step 2605, the UE may receive from the base station a linked search space in which the same DCI is repeatedly transmitted among the plurality of search spaces.

[0461] In step 2610, the terminal may receive DCI scheduling a PDSCH in the linked search space.

[0462] In step 2615, the terminal may determine search spaces that do not satisfy the <condition> based on the configuration information of the linked search spaces.

[0463] In step 2620, the UE may determine an aggregation level in the search space that does not satisfy the <condition>. Since there is no ambiguity of another aggregation level when the <condition> is not satisfied, the UE may determine the aggregation level assumed when receiving the DCI as the aggregation level of the search space that does not satisfy the <condition>.

[0464] In step 2625, the terminal may determine an aggregation level in the search space that satisfies the <condition> based on the determined aggregation level. The terminal may determine the aggregation level to be the same as the aggregation level of the search space that does not satisfy the <condition>.

[0465] In operation 2630, the UE may receive the PDSCH by rate matching based on the aggregation level determined in the search space not satisfying the <condition> and the aggregation level determined in the search space satisfying the <condition>. The UE may determine resources not used for the PDSCH by assuming the same aggregation level determined in the search space not satisfying the <condition> and the search space satisfying the <condition>.

[0466] [Method 2-4: Include aggregation level indicator]

[0467] Methods 2-1, 2-2, and 2-3 propose a method in which the terminal determines the aggregation level, but method 2-4 proposes a method in which the base station includes information on the aggregation level of PDCCH in DCI and transmits it.

[0468] The base station may transmit an indicator indicating an aggregation level of the PDCCH on which the DCI is transmitted, including the indicator in the DCI for scheduling the PDSCH. For example, the indicator may be composed of 1 bit, and the 1 bit may indicate either an aggregation level of 8 or an aggregation level of 16. The terminal may receive the DCI for scheduling the PDSCH, check the indicator from the received DCI, and determine the aggregation level using the indicator. The terminal may apply the determined aggregation level to all linked search spaces. That is, time-frequency resources of PDCCH candidates corresponding to the same aggregation level indicated by the indicator in all linked search spaces may not be used for PDSCH reception.

[0469] As yet another example, the indicator may be indicated by a specific combination of DCI fields included in the DCI rather than by separate bits. As an example, when a modulation and coding scheme (MCS) field included in the DCI received by the terminal indicates a low MCS value, the channel condition may be poor and thus may be considered as an aggregation level of 16. As an example, when a time-domain resource assignment (TDRA) field included in the DCI received by the terminal indicates repeated transmission of PDSCH, the channel condition may be poor and thus may be considered as an aggregation level of 16.

[0470] As another example, the indicator may be indicated by borrowing some bits of existing bits of DCI instead of a separate bit. As an example, a specific bit of a frequency-domain resource assignment (FDRA) field included in the DCI received by the terminal may be re-purposed for the indicator. As an example, a specific bit of an MCS field included in the DCI received by the terminal may be re-purposed for the indicator. The specific bit of the MCS field may be the most significant bit (MSB). When the MSB bit of the MCS field is used, the bits that the MCS field can indicate are 4 bits, and up to 16 code points can be indicated. Here, the up to 16 code points may be composed of code points corresponding to low MCS and code points indicating only modulation order.

[0471] As yet another example, the indicator may be indicated by a separate RNTI. That is, when receiving DCI scrambled with a specific RNTI, the aggregation level of the PDCCH transmitted by the DCI may be considered to be a specific value (e.g., 8 or 16). Exemplarily, when receiving DCI scrambled with MCS-C-RNTI, the UE may consider the aggregation level of the PDCCH transmitted by the DCI to be 16. This is because MCS-C-RNTI is used when higher reliability is required.

[0472] For reference, when the terminal receives DCI on PDCCH candidates with aggregation level 1, 2, or 4, the terminal may ignore the indicator. In other words, the indicator is usable when the terminal receives DCI on PDCCH candidates with aggregation level 8 or 16. Furthermore, the indicator may be used when the linked search space satisfies <condition> and the terminal receives PDCCH candidates with aggregation level 8 or 16. In other cases, the terminal may ignore the indicator.

[0473] Alternatively, the terminal can assume one aggregation level without the indicator. This means that the base station assumes that it always transmits PDCCH only at a specified aggregation level when the <condition> is satisfied. For example, one aggregation level value of 8 or 16 can be assumed. The base station can set one value to the terminal in a higher layer. The terminal can expect to receive only PDCCH candidates corresponding to one aggregation level value if there is a search space that satisfies the linked <condition>. For example, if the base station indicates 16 as one value to the terminal, the terminal can receive (monitor) PDCCH candidates with aggregation level 16, but not receive (monitor) PDCCH candidates with aggregation level 8. Therefore, there is no more ambiguity about the aggregation level.

[0474] <Third embodiment: Method for distinguishing between aggregation level 8 and aggregation level 16 and method for determining PUCCH resources accordingly>

[0475] A maximum of 32 PUCCH resources may be configured for a PUCCH set in a terminal. A DCI for scheduling a PDSCH or a DCI for indicating HARQ-ACK transmission (e.g., SPS PDSCH release DCI, DCI for triggering a type-3 HARQ-ACK codebook, DCI for indicating Scell ​​dormancy, etc.) must indicate one PUCCH resource among the maximum of 32 PUCCH resources. However, currently, the DCI includes a maximum of 3-bit PUCCH resource indicator field. Therefore, one PUCCH resource among the maximum of 32 PUCCH resources must be indicated using other information in addition to the 3-bit PUCCH resource indicator field. To this end, in 3GPP Rel-15, the lowest CCE index (or starting CCE index / first CCE index) of a PDCCH in which a DCI is transmitted is used.

[0476] FIG. 27 illustrates a method for determining a PUCCH resource according to one embodiment of the present disclosure.

[0477] Referring to FIG. 27, the lowest CCE index of PDCCH X 2700 at aggregation level 8 is n CCE = 16 (2755), and the lowest CCE index of PDCCH Y 2705 at aggregation level 16 is n CCE = 0 (2750). If the terminal receives DCI on PDCCH X with aggregation level 8, the PUCCH resource may be determined according to the lowest CCE index, 16. In the example of FIG. 27, PUCCH resource A (2710) is indicated. If the terminal receives DCI on PDCCH Y with aggregation level 16, the PUCCH resource may be determined according to the lowest CCE index, 0. In the example of FIG. 27, PUCCH resource B 2715 is indicated. In this way, since the lowest CCE indexes of the PDCCHs on which the terminals receive DCI are different, different PUCCH resources may be indicated.

[0478] More specifically, the PUCCH resource may be determined according to Equation 3.

[0479] [Formula 3]

[0480]

number

[0481] In formula 3, N CCE,p is the number of CCEs included in CORESET p where DCI is received, and N CCE,p is the lowest CCE index (or starting CCE index) of the PDCCH on which DCI is received, Δ PRI R is the value of the PUCCH resource indicator field of the DCI, and is one of the values ​​0, 1, 2, 3, 4, 5, 6, and 7. PUCCH is the number of PUCCH resources configured in the PUCCH resource set, which is greater than or equal to 8 and less than or equal to 32. PUCCH is 0,1,…,RPUCCH It can have one of the following values: -1.

[0482] In order to determine the PUCCH resource according to Equation 3, the terminal must determine the lowest CCE index (or starting CCE index) of the PDCCH on which the DCI is received. According to the above-mentioned Figures 15A and 15B and <Condition>, the terminal receives DCI, but it may be ambiguous whether the DCI is transmitted on a PDCCH of aggregation level 8 or on a PDCCH of aggregation level 16. However, referring to Figures 15A and 15B and <Condition>, the PDCCH of aggregation level 8 and the PDCCH of aggregation level 16 may always start from the same CCE. Therefore, although there is ambiguity in the aggregation level, the terminal can determine the lowest CCE index (or starting CCE index) without ambiguity. In other words, when a 1-symbol, non-interleaving mapping CORESET is configured and a terminal receives (monitors) a PDCCH in a search space including a PDCCH candidate of aggregation level 8 and a PDCCH candidate of aggregation level 16 starting from the same CCE index, the terminal can unambiguously determine the lowest CCE index (or starting CCE index).

[0483] The lowest CCE index (or starting CCE index) of the PDCCH received in each linked search space may be different. Therefore, in this case, the lowest CCE index of the PDCCH received in one search space should be used. For example, the lowest CCE index of the PDCCH received in the search space with the lowest search space index among the linked search spaces can be used.

[0484] However, referring to FIG. 28, when one search space in the linked search spaces satisfies <condition> but the other search space does not satisfy <condition>, it may be unclear which CCE index the terminal should use to determine the PUCCH resource.

[0485] As stated above, the <conditions> are as follows:

[0486] <Condition>: 1 symbol, non-interleaving mapping CORESET is set, and includes aggregation level 8 PDCCH candidates and aggregation level 16 PDCCH candidates starting with the same CCE index

[0487] FIG. 28 illustrates an example of a method for determining a PUCCH resource in the case of PDCCH repeated transmission and aggregation level decision ambiguity according to one embodiment of the present disclosure.

[0488] Referring to FIG. 28, in search space 2 2805 that satisfies the <condition>, the terminal cannot determine whether the aggregation level of the PDCCH on which the DCI is transmitted is 8 or 16. In search space 1 2800 that does not satisfy the <condition>, the terminal can determine which PDCCH is transmitted. However, as described above, the terminal can perform individual PDCCH decoding using only search space 2, and the channel environment corresponding to search space 1 may deteriorate (e.g., high interference or blocking of the TRP (transmission and reception point) where search space 1 is transmitted) and the terminal may not be able to receive the PDCCH in search space 1. In this case, the terminal can receive the PDCCH using only the PDCCH transmitted in search space 2. Therefore, a problem occurs when the terminal determines the lowest CCE index (start CCE index) of the PDCCH received in search space 1. For reference, as described above, the PUCCH resource may be determined using the search space having the lowest index among the linked search spaces, ie, the lowest CCE index (starting CCE index) of the PDCCH received in search space 1.

[0489] [Method 3-1] Use the lowest CCE index (starting CCE index) of the PDCCH received in the search space that satisfies <Condition>

[0490] Referring to FIG. 28, in a search space (e.g., search space 2 2805) that satisfies <condition> among the linked search spaces, even if there is ambiguity regarding the aggregation level, the lowest CCE index (start CCE index) can be determined without ambiguity. Therefore, when using the lowest CCE index (start CCE index) 2860, the terminal and the base station can determine the PUCCH resource. In other words, when the terminal receives a PDCCH that transmits DCI, the aggregation level of the PDCCH is 8 (2820) or 16 (2825), and the PDCCH satisfies <condition> in at least one of the linked search spaces, the PUCCH resource can be determined using the lowest CCE index (start CCE index) 2860 of the PDCCH in the search space that satisfies the <condition>. In general cases other than the above case, the PUCCH resource can always be determined using the lowest CCE index (start CCE index) of the PDCCH received in a search space with a low index.

[0491] [Method 3-2] Using the lowest CCE index (starting CCE index) of PDCCH, which is one aggregation level

[0492] Referring to FIG. 28, the search space with the lowest search space index is search space 1 2800, and it may be ambiguous whether a PDCCH with aggregation level 8 or a PDCCH with aggregation level 16 has been received in the search space. To resolve this ambiguity, it may be assumed that a PDCCH has been received at one aggregation level. For example, it may be assumed that a PDCCH has always been received at a low aggregation level, i.e., aggregation level 8 2810. Referring to FIG. 28, the terminal selects n 2800, which is the lowest CCE index (starting CCE index) with aggregation level 8 in search space 1 with the lowest index. CCEAs another example, it may be assumed that the PDCCH is always received at the highest aggregation level, i.e., aggregation level 16 (2815). Referring to FIG. 28, the UE may determine the PUCCH resource based on n = 16 (2855), which is the lowest CCE index (starting CCE index) of aggregation level 16, which is the highest aggregation level in search space 1 with the lowest index. CCE The PUCCH resource can be determined based on .times. ...

[0493] [Method 3-3] Use the lowest CCE index (starting CCE index) of the received PDCCH

[0494] The terminal can use the lowest CCE index (start CCE index) of the received PDCCH. In this case, although there is potential ambiguity regarding the aggregation level of the PDCCH, the terminal ignores the ambiguity and assumes that the received PDCCH is the PDCCH transmitted by the base station.

[0495] Referring to FIG. 28, assuming that the terminal receives a PDCCH 2810 of aggregation level 8, the lowest CCE index (start CCE index) of the PDCCH of aggregation level 8 in search space 1, which is the search space with the lowest index, is n CCE = 16 (2855) based on which the PUCCH resource can be determined.

[0496] Since the terminal ignores the ambiguity regarding the aggregation level of the PDCCH, the terminal may potentially transmit the PUCCH on the wrong PUCCH resource, but at least the base station knows the PUCCH that the terminal may use.

[0497] For example, referring to FIG. 28, the terminal selects n , which is the lowest CCE index (start CCE index) of the PDCCH at aggregation level 8 of search space 1, which is the search space with the lowest index. CCE= 16, and the lowest CCE index (starting CCE index) of the PDCCH resource and aggregation level 16 PDCCH CCE = 0. Therefore, the base station receives and decodes both of the two PUCCH resources, thereby determining which PUCCH is used for transmission.

[0498] The above-mentioned method 2-4 of indicating the aggregation level of PDCCH using DCI may be applied when determining the PUCCH. A terminal may receive DCI, obtain an indicator indicating the aggregation level from the DCI, and determine the aggregation level using the indicator. Based on the aggregation level, a PDCCH may be selected in a search space with the lowest index, and a PUCCH resource may be determined according to the lowest CCE index (start CCE index) of the PDCCH.

[0499] 29 is a flowchart of a terminal operation according to an embodiment of the present disclosure. The order of operations in FIG. 29 may be changed, two or more operations may be combined, or some steps may be omitted.

[0500] 29, the terminal may confirm the first search space set and the second search space set in step S2910. The base station may confirm the first search space set and the second search space set to be set in the terminal, and set the first search space set and the second search space set in the terminal.

[0501] As described above, the search space is a set of downlink control channel candidates (Candidates) consisting of CCEs that the terminal should attempt to decode at a given aggregation level, and there may be various aggregation levels that create one set with 1, 2, 4, 8, and 16 CCEs. A search space set (Set) may be defined as a set of search spaces at all the set aggregation levels.

[0502] Each search space set may be associated with a CORESET. For example, the first search space set may be associated with a first CORESET, and the second search space set may be associated with a second CORESET. A search space index may be set for each search space set. The search space index is information for identifying a search space set. For example, a first index may be set for the first search space set, and a second index may be set for the second search space set.

[0503] The first search space set and the second search space set may be linked to each other based on configuration information. The PDCCH may be repeatedly received based on the linked search space sets. For example, the configuration information may be received from a base station. The configuration information may include information (or an identifier) ​​for linking the first search space set and the second search space set to each other for the repeated reception of the PDCCH. For example, the configuration information may include the above-mentioned first information and / or second information.

[0504] For example, a first search space set may include a first PDCCH candidate of CCE aggregation level 8 and a third PDCCH candidate of CCE aggregation level 16. An index of a first CCE (start CCE index) of the first PDCCH candidate may be the same as an index of a first CCE (start CCE index) of the third PDCCH candidate. A second search space set may include a second PDCCH candidate of CCE aggregation level 8 and a fourth PDCCH candidate of CCE aggregation level 16. An index of a first CCE (start CCE index) of the second PDCCH candidate may be different from an index of a first CCE (start CCE index) of the fourth PDCCH candidate. For example, the terminal may determine that a CCEs-to-REGs mapping type of the first CORESET associated with the first search space set is set to non-interleaving mapping and that a time duration of the first CORESET is one symbol.

[0505] In step S2920, the terminal may receive a PDCCH. The base station may transmit a PDCCH to the terminal. A DCI for scheduling a PDSCH or a DCI for instructing HARQ-ACK transmission (e.g., an SPS PDSCH release DCI, a DCI for triggering a type-3 HARQ-ACK codebook, a DCI for instructing Scell ​​dormancy, etc.) may be received on the PDCCH. For example, the PDCCH may be received based on each of a first search space set and a second search space set. As an example, the PDCCH may be received based on the first PDCCH candidate and the second PDCCH candidate. Or, the PDCCH may be received based on the third PDCCH candidate and the fourth PDCCH candidate.

[0506] In step S2930, the terminal may determine a PUCCH resource. The PUCCH resource may be determined based on an index of a first CCE (or a starting CCE) among CCEs for the PDCCH.

[0507] For example, when the second index of the second search space set is smaller than the first index of the first search space set, a first CCE may be determined based on the second search space set. Specifically, the index of the first CCE (or starting CCE) may be determined based on a CCE aggregation level of a PDCCH candidate associated with the second search space set having a smaller index. As an example, the index of the first CCE (starting CCE index) of the second PDCCH candidate of CCE aggregation level 8 in the second search space may be different from the index of the first CCE (starting CCE index) of the fourth PDCCH candidate of CCE aggregation level 16. In this case, the index of the first CCE (or starting CCE) may be determined based on the index of the first CCE (starting CCE index) of the fourth PDCCH candidate of CCE aggregation level 16.

[0508] The PUCCH resource may be determined by further considering the value of a PUCCH Resource Indicator field in DCI carried on the PDCCH.

[0509] In step S2940, the terminal may transmit a PUCCH based on the determined PUCCH resource. The base station may receive a PUCCH from the terminal. For example, the PUCCH may include HARQ-ACK information.

[0510] The proposed methods and / or embodiments described above (eg, the first embodiment, the second embodiment, the third embodiment, etc.) may be implemented in combination with each other.

[0511] Also, the above-mentioned proposed methods and / or embodiments (eg, the first embodiment, the second embodiment, the third embodiment, etc.) may be performed by the terminals and / or base stations of FIGS. 30 and 31.

[0512] FIG. 30 is a diagram illustrating a structure of a terminal in a wireless communication system according to one embodiment of the present disclosure.

[0513] Referring to FIG. 30, the terminal may include a transceiver, referred to as a terminal receiver 3000 and a terminal transmitter 3010, a memory (not shown), and a terminal processor (or terminal controller or processor) 3005. The transceivers 3000 and 3010, the memory, and the terminal processor 3005 of the terminal may operate according to the terminal communication method described above. However, the components of the terminal are not limited to the above examples. For example, the terminal may include more or fewer components than the above components. In addition, the transceiver, memory, and processor may be embodied in the form of a single chip.

[0514] The transceiver unit can transmit and receive signals to and from a base station. Here, the signals may include control information and data. To this end, the transceiver unit may be configured with an RF transmitter that upconverts and amplifies the frequency of a signal to be transmitted, and an RF receiver that performs low-noise amplification and downconverts the frequency of a received signal. However, this is merely one embodiment of the transceiver unit, and the components of the transceiver unit are not limited to an RF transmitter and an RF receiver.

[0515] The transceiver unit can also receive signals via a wireless channel and output them to the processor, and transmit signals output from the processor via a wireless channel.

[0516] The memory can store programs and data necessary for the operation of the terminal. The memory can also store control information or data included in signals transmitted and received by the terminal. The memory can be configured as a storage medium such as a ROM, a RAM, a hard disk, a CD-ROM, a DVD, or a combination of storage media. The memory can also be multiple.

[0517] The terminal processing unit 3005 can control a series of processes so that the terminal can operate according to the above-mentioned embodiment. For example, the processor can control components of the terminal to receive DCI consisting of two types of layers and simultaneously receive multiple PDSCHs. For example, the terminal device processing unit 3005 confirms a first search space set associated with a first CORESET and a second search space set associated with a second CORESET linked based on the configuration information, where the first search space set having a first index includes a first PDCCH candidate having CCE AL 8 and a third PDCCH candidate having CCE AL 16, and the second search space set having a second index includes a second PDCCH candidate having CCE AL 8 and a fourth PDCCH candidate having CCE AL 16, receives a PDCCH based on the first PDCCH candidate and the second PDCCH candidate or based on the third PDCCH candidate and the fourth PDCCH candidate via the transceiver unit, and determines a PUCCH resource based on the index of the first CCE, where if the first index of the first search space set is greater than the second index of the second search space set, the index of the first CCE is determined based on the CCE AL of the PDCCH candidate associated with the second search space set having the second index, and is configured to transmit the PUCCH on the determined PUCCH resource via the transceiver unit. There may be a plurality of terminal processors 3005, and each of the terminal processors 3005 can control the components of the terminal by executing a program stored in the memory.

[0518] FIG. 31 is a diagram illustrating a base station in a wireless communication system according to one embodiment of the present disclosure.

[0519] Referring to FIG. 31, the base station may include a transceiver unit, referred to as a base station receiver unit 3100 and a base station transmitter unit 3110, a memory (not shown), and a base station processing unit (3105, or a base station controller or processor). The transceiver units 3100 and 3110, the memory, and the base station processing unit 3105 of the base station may operate according to the base station communication method described above. However, the components of the base station are not limited to the above examples. For example, the base station may include more or fewer components than the above components. In addition, the transceiver unit, the memory, and the processor may be embodied in the form of a single chip.

[0520] The transceiver can transmit and receive signals to and from the terminal. Here, the signals may include control information and data. To this end, the transceiver may be composed of an RF transmitter that upconverts and amplifies the frequency of a signal to be transmitted, and an RF receiver that performs low-noise amplification and downconverts the frequency of a received signal. However, this is merely one embodiment of the transceiver, and the components of the transceiver are not limited to an RF transmitter and an RF receiver.

[0521] The transceiver unit can also receive signals via a wireless channel and output them to the base station processing unit 3105, and transmit signals output from the processor via a wireless channel.

[0522] The memory can store programs and data necessary for the operation of the base station. The memory can also store control information or data included in signals transmitted and received by the base station. The memory can be configured as a storage medium such as a ROM, a RAM, a hard disk, a CD-ROM, a DVD, etc., or a combination of storage media. Also, there can be multiple memories.

[0523] The base station processing unit 3105 can control a series of processes so that the base station can operate according to the above-mentioned embodiment of the present disclosure. For example, the base station processing unit 3105 can configure two-layer DCI including allocation information for multiple PDSCHs and control each component of the base station to transmit the DCI. For example, the base station processing unit 3105 confirms a first search space set associated with a first CORESET and a second search space set associated with a second CORESET that are linked based on the configuration information, the first search space set having a first index includes a first PDCCH candidate having CCE AL 8 and a third PDCCH candidate having CCE AL 16, and the second search space set having a second index includes a second PDCCH candidate having CCE AL 8 and a fourth PDCCH candidate having CCE AL 16, and is configured to transmit a PDCCH to a terminal based on the first PDCCH candidate and the second PDCCH candidate or based on the third PDCCH candidate and the fourth PDCCH candidate, and to receive a PUCCH from the terminal on a PUCCH resource, the PUCCH resource being confirmed based on an index of a first CCE of the PDCCH, and if a first index of the first search space set is greater than a second index of the second search space set, the index of the first CCE is greater than a CCE of a PDCCH candidate associated with the second search space set having a second index. Related to AL.

[0524] There may be a plurality of base station processors 3105, and each of the base station processors 3105 can control the components of the base station by executing a program stored in the memory.

[0525] The methods according to the embodiments described in the claims or specification of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

[0526] When embodied in software, a computer-readable storage medium may be provided that stores one or more programs (software modules). The one or more programs stored in the computer-readable storage medium are configured for execution by one or more processors in an electronic device. The one or more programs include instructions that cause the electronic device to execute a method according to the embodiments described in the claims or specification of the present disclosure.

[0527] Such programs (software modules, software) may be stored in random access memory, non-volatile memory including flash memory, Read Only Memory (ROM), Electrically Erasable Programmable Read Only Memory (EEPROM), magnetic disc storage device, Compact Disc-ROM (CD-ROM), Digital Versatile Discs (DVDs) or other forms of optical storage, magnetic cassette, or in a memory configured as a combination of some or all of them. Also, each of the memory components may be included in a plurality of pieces.

[0528] The program may be stored in an attachable storage device accessible through a communication network such as the Internet, an intranet, a local area network (LAN), a wide LAN (WLAN), or a storage area network (SAN), or a combination thereof. Such a storage device may be connected to an apparatus that performs the embodiments of the present disclosure through an external port. Also, a separate storage device on the communication network may be connected to an apparatus that performs the embodiments of the present disclosure.

[0529] In the specific embodiments of the present disclosure described above, the components included in the invention are expressed as singular or plural according to the specific embodiments presented. However, the expressions singular or plural are selected according to the presented situation for convenience of explanation, and the present disclosure is not limited to singular or plural components, and therefore, even components expressed as plural may be composed of singular, and even components expressed as singular may be composed of plural. Meanwhile, the embodiments of the present disclosure disclosed in the present specification and drawings are merely specific examples presented to easily explain the technical contents of the present disclosure and to aid in the understanding of the present disclosure, and are not intended to limit the scope of the present disclosure. That is, it is obvious to a person having ordinary knowledge in the technical field to which the present disclosure belongs that other modified examples based on the technical idea of ​​the present disclosure can be implemented. In addition, each of the above embodiments may be operated in combination as necessary. For example, one embodiment of the present disclosure and a part of another embodiment may be combined with each other to operate a base station and a terminal. For example, a part of the first embodiment and a part of the second embodiment of the present disclosure may be combined with each other to operate a base station and a terminal. In addition, although the above embodiment has been presented based on an FDD LTE system, other modifications based on the technical ideas of the above embodiment may be implemented in other systems such as a TDD LTE system, a 5G or an NR system.

[0530] Meanwhile, in the drawings illustrating the method of the present invention, the order of description does not necessarily correspond to the order of execution, and the order of operations may be changed or operations may be executed in parallel.

[0531] Alternatively, a drawing illustrating a method of the present invention may include only some of the components, with some components omitted, without departing from the essence of the present invention.

[0532] Furthermore, the method of the present invention may be implemented by combining some or all of the contents included in each embodiment without departing from the essence of the invention.

[0533] While the present disclosure has been illustrated and described with reference to various embodiments thereof, it will be understood by those having ordinary skill in the art to which the present disclosure pertains that the same may be readily modified in other specific forms without departing from the spirit or scope of the present disclosure as defined by the appended claims and equivalents thereof. [Explanation of symbols]

[0534] 3000 Terminal receiving unit 3005 Terminal Processing Unit 3010 Terminal transmitter 3100 Base station receiver 3105 Base station processing unit 3110 Base station transmitter

Claims

1. 1. A method performed by a terminal in a wireless communication system, comprising: receiving configuration information for a first search space (SS) set and a second SS set, wherein the first SS set having a first index includes a first physical downlink control channel (PDCCH) candidate having a control channel element (CCE) aggregation level (AL) of 8 and a third PDCCH candidate having a CCE AL of 16, and the second SS set having a second index includes a second PDCCH candidate having a CCE AL of 8 and a fourth PDCCH candidate having a CCE AL of 16; receiving a PDCCH based on the configuration information; determining a physical uplink control channel (PUCCH) resource based on an index of a first CCE for the PDCCH, wherein if the first index of the first SS set is greater than the second index of the second SS set, the index of the first CCE is determined based on a PDCCH candidate having a CCE AL16 associated with the second SS set having the second index; transmitting a PUCCH based on the determined PUCCH resource; A method comprising:

2. A mapping type of a CCE to a resource element group (REG) of a first control resource set (CORESET) associated with the first SS set is set to non-interleaved mapping, and the time length of the first CORESET is 1 symbol; The method of claim 1, wherein an index of a first CCE of the first PDCCH candidate is the same as an index of a first CCE of the third PDCCH candidate.

3. If an index of a first CCE of the second PDCCH candidate in the second SS set is different from an index of a first CCE of the fourth PDCCH candidate, the index of the first CCE for the PDCCH is determined from the index of the first CCE of the fourth PDCCH candidate having the CCE AL 16; The method of claim 2, wherein the PDCCH is received based on the first PDCCH candidate and the second PDCCH candidate or based on the third PDCCH candidate and the fourth PDCCH candidate.

4. the second SS set is associated with a second CORESET; The method of claim 1, wherein the PUCCH resource is determined further based on a value of a PUCCH resource indicator field in downlink control information (DCI) of the PDCCH.

5. The configuration information includes information about a link between the first SS set and the second SS set for PDCCH repetition, The method of claim 1 , wherein the first SS set and the second SS set are linked based on the configuration information.

6. 1. A method performed by a base station in a wireless communication system, comprising: transmitting configuration information for a first search space (SS) set and a second SS set to a terminal, wherein the first SS set having a first index includes a first physical downlink control channel (PDCCH) candidate having a control channel element (CCE) aggregation level (AL) of 8 and a third PDCCH candidate having a CCE AL of 16, and the second SS set having a second index includes a second PDCCH candidate having a CCE AL of 8 and a fourth PDCCH candidate having a CCE AL of 16; transmitting a PDCCH to the terminal based on the configuration information; receiving a physical uplink control channel (PUCCH) from the terminal based on PUCCH resources; Including, The PUCCH resource is identified based on an index of a first CCE for the PDCCH; When the first index of the first SS set is greater than the second index of the second SS set, the index of the first CCE of the PDCCH is associated with a PDCCH candidate having a CCE AL16 associated with the second SS set having the second index.

7. A mapping type of a CCE to a resource element group (REG) of a first control resource set (CORESET) associated with the first SS set is set to non-interleaved mapping, and the time length of the first CORESET is 1 symbol; an index of a first CCE of the first PDCCH candidate is the same as an index of a first CCE of the third PDCCH candidate; 7. The method of claim 6, wherein, when an index of a first CCE of the second PDCCH candidate in the second SS set is different from an index of a first CCE of the fourth PDCCH candidate, the index of the first CCE for the PDCCH is determined from the index of the first CCE of the fourth PDCCH candidate having the CCE AL 16.

8. the PUCCH resource is identified further based on a value of a PUCCH resource indicator field in downlink control information (DCI) of the PDCCH; the second SS set is associated with a second CORESET; The method of claim 6, wherein the PDCCH is transmitted based on the first PDCCH candidate and the second PDCCH candidate or based on the third PDCCH candidate and the fourth PDCCH candidate.

9. The configuration information includes information about a link between the first SS set and the second SS set for PDCCH repetition, The method of claim 6 , wherein the first SS set and the second SS set are linked based on the configuration information.

10. A terminal in a wireless communication system, a transmitter / receiver; configuration information for a first search space (SS) set and a second SS set is received via the transceiver unit, the first SS set having a first index includes a first physical downlink control channel (PDCCH) candidate having a control channel element (CCE) aggregation level (AL) of 8 and a third PDCCH candidate having a CCE AL of 16, and the second SS set having a second index includes a second PDCCH candidate having a CCE AL of 8 and a fourth PDCCH candidate having a CCE AL of 16; receiving a PDCCH based on the setting information via the transceiver unit; determining a physical uplink control channel (PUCCH) resource based on an index of a first CCE for the PDCCH, and when the first index of the first SS set is greater than the second index of the second SS set, the index of the first CCE is determined based on a PDCCH candidate having a CCE AL16 associated with the second SS set having the second index; a controller configured to transmit a PUCCH based on the determined PUCCH resource via the transceiver unit and operatively connected to the transceiver unit; Including, the terminal.

11. A mapping type of a CCE to a resource element group (REG) of a first control resource set (CORESET) associated with the first SS set is set to non-interleaved mapping, and the time length of the first CORESET is 1 symbol; an index of a first CCE of the first PDCCH candidate is the same as an index of a first CCE of the third PDCCH candidate; the second SS set is associated with a second CORESET; 11. The terminal of claim 10, wherein, when an index of a first CCE of the second PDCCH candidate in the second SS set is different from an index of a first CCE of the fourth PDCCH candidate, the index of the first CCE for the PDCCH is determined from the index of the first CCE of the fourth PDCCH candidate having the CCE AL 16.

12. The configuration information includes information about a link between the first SS set and the second SS set for PDCCH repetition, The PUCCH resource is determined further based on a value of a PUCCH resource indicator field in downlink control information (DCI) of the PDCCH; The terminal of claim 10, wherein the PDCCH is received based on the first PDCCH candidate and the second PDCCH candidate or based on the third PDCCH candidate and the fourth PDCCH candidate.

13. A base station in a wireless communication system, comprising: a transmitter / receiver; transmit configuration information for a first search space (SS) set and a second SS set to a terminal, the first SS set having a first index including a first physical downlink control channel (PDCCH) candidate having a control channel element (CCE) aggregation level (AL) of 8 and a third PDCCH candidate having a CCE AL of 16, and the second SS set having a second index including a second PDCCH candidate having a CCE AL of 8 and a fourth PDCCH candidate having a CCE AL of 16; Transmitting a PDCCH to the terminal based on the setting information; a controller configured to receive a physical uplink control channel (PUCCH) from the terminal based on PUCCH resources and functionally connected to the transceiver; Including, The PUCCH resource is identified based on an index of a first CCE for the PDCCH; When the first index of the first SS set is greater than the second index of the second SS set, the index of the first CCE of the PDCCH is associated with a PDCCH candidate having CCE AL16 associated with the second SS set having the second index.

14. A mapping type of a CCE to a resource element group (REG) of a first control resource set (CORESET) associated with the first SS set is set to non-interleaved mapping, and the time length of the first CORESET is 1 symbol; an index of a first CCE of the first PDCCH candidate is the same as an index of a first CCE of the third PDCCH candidate; the second SS set is associated with a second CORESET; 14. The base station of claim 13, wherein, when an index of a first CCE of the second PDCCH candidate in the second SS set is different from an index of a first CCE of the fourth PDCCH candidate, the index of the first CCE for the PDCCH is determined from the index of the first CCE of the fourth PDCCH candidate having the CCE AL 16.

15. The configuration information includes information about a link between the first SS set and the second SS set for PDCCH repetition, The base station according to claim 13, wherein the PDCCH is transmitted based on the first PDCCH candidate and the second PDCCH candidate or based on the third PDCCH candidate and the fourth PDCCH candidate.

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