WO2021162431A1 - Default beam setting method and device for network cooperative communication - Google Patents

Abstract

Disclosed are: a communication technique for merging, with IoT technology, a 5G communication system for supporting a data transmission rate higher than that of a 4G system; and a system therefor. The present disclosure can be applied to intelligent services (for example, smart homes, smart buildings, smart cities, smart cars or connected cars, healthcare, digital education, retail, security- and safety-related services, and the like) on the basis of 5G communication technology and IoT-related technology. According to one embodiment of the disclosure, provided is a method by which a terminal determines a default beam to be assumed if beam information for receiving control information is not indicated.

Description

Basic beam setting method and apparatus for network cooperative communication

The present disclosure relates to a wireless communication system, and relates to a beam setting method and apparatus for network cooperative communication in a wireless communication system.

Efforts are being made to develop an improved 5G communication system or pre-5G communication system in order to meet the increasing demand for wireless data traffic after commercialization of the 4G communication system. For this reason, the 5G communication system or the pre-5G communication system is called a system after the 4G network (Beyond 4G Network) communication system or after the LTE system (Post LTE). In order to achieve high data rates, 5G communication systems are being considered for implementation in very high frequency (mmWave) bands (eg, 60 gigabytes (60 GHz) bands). In order to mitigate the path loss of radio waves and increase the propagation distance of radio waves in the very high frequency band, in the 5G communication system, beamforming, massive MIMO, and Full Dimensional MIMO (FD-MIMO) are used. ), array antenna, analog beam-forming, and large scale antenna technologies are being discussed. In addition, for network improvement of the system, in the 5G communication system, an evolved small cell, an advanced small cell, a cloud radio access network (cloud RAN), and an ultra-dense network (ultra-dense network) , Device to Device communication (D2D), wireless backhaul, moving network, cooperative communication, Coordinated Multi-Points (CoMP), and reception interference cancellation Technology development is underway. In addition, in the 5G system, Hybrid FSK and QAM Modulation (FQAM) and Sliding Window Superposition Coding (SWSC), which are advanced coding modulation (ACM) methods, and Filter Bank Multi Carrier (FBMC), NOMA, which are advanced access technologies, (non orthogonal multiple access), and sparse code multiple access (SCMA) are being developed.

On the other hand, the Internet is evolving from a human-centered connection network where humans create and consume information to an Internet of Things (IoT) network that exchanges and processes information between distributed components such as objects. Internet of Everything (IoE) technology, which combines big data processing technology through connection with cloud servers, etc. with IoT technology, is also emerging. In order to implement IoT, technology elements such as sensing technology, wired and wireless communication and network infrastructure, service interface technology, and security technology are required. , M2M), and MTC (Machine Type Communication) are being studied. In the IoT environment, an intelligent IT (Internet Technology) service that collects and analyzes data generated from connected objects and creates new values in human life can be provided. IoT is a field of smart home, smart building, smart city, smart car or connected car, smart grid, health care, smart home appliance, advanced medical service, etc. can be applied to

Accordingly, various attempts are being made to apply the 5G communication system to the IoT network. For example, in technologies such as sensor network, machine to machine (M2M), and machine type communication (MTC), 5G communication technology is implemented by techniques such as beam forming, MIMO, and array antenna. there will be The application of a cloud radio access network (cloud RAN) as the big data processing technology described above is an example of the convergence of 5G technology and IoT technology.

The present disclosure (disclosure) provides a method of determining a default beam that the terminal assumes when beam information for receiving control information is not indicated in a network cooperative communication system.

In order to solve the above problems, according to an embodiment of the present disclosure, there is provided a method of a terminal in a wireless communication system. In the method of a terminal in a wireless communication system, the method includes, from a base station, first information about at least one first CORESET having a control resource set (CORESET) related index of 0 and at least one first information having a CORESET related index of 1 2 Receiving second information about CORESET; checking whether control information for activating at least one transmission configuration indicator (TCI) state for the at least one second CORESET is received; checking a default beam based on the second information when the control information is not received; and receiving downlink control information from the at least one second CORESET based on the default beam.

In addition, according to an embodiment of the present disclosure, a method of a base station in a wireless communication system is provided. The method includes transmitting first information about at least one first CORESET having a control resource set (CORESET)-related index of 0 and second information about at least one second CORESET having a CORESET-related index of 1 to the terminal ; and transmitting downlink control information to the terminal in the at least one second CORESET, wherein the base station determines at least one transmission configuration indicator (TCI) state for the at least one second CORESET. When activating control information is not transmitted, the downlink control information is received based on a default beam, and the default beam is identified based on the second information.

In addition, according to an embodiment of the present disclosure, a terminal of a wireless communication system is provided. The terminal includes a transceiver; and the transceiver unit to receive, from the base station, first information on at least one first CORESET having a control resource set (CORESET)-related index of 0 and second information on at least one second CORESET having a CORESET-related index of 1 control, check whether control information for activating at least one transmission configuration indicator (TCI) state for the at least one second CORESET is received, and if the control information is not received, the second It is characterized in that it includes a control unit that identifies a default beam based on the information and controls the transceiver to receive downlink control information from the at least one second CORESET based on the default beam.

In addition, according to an embodiment of the present disclosure, a base station of a wireless communication system is provided. The base station, the transceiver; and controlling the transceiver to transmit first information on at least one first CORESET having a CORESET-related (control resource set) index of 0 and second information on at least one second CORESET having a CORESET-related index of 1 to the terminal. and a controller for controlling the transceiver to transmit downlink control information to the terminal in the at least one second CORESET, wherein the base station includes at least one transmission configuration indicator (TCI) for the at least one second CORESET. ) when control information for activating a state is not transmitted, the downlink control information is received based on a default beam, and the default beam is identified based on the second information do.

According to the present disclosure, in a cooperative communication system, when the terminal does not set a beam for receiving control information from the base station, a method of pre-arranging a basic operation and a default beam between the terminal and the base station is provided. Accordingly, it is possible to reduce the reduction in power consumption of the terminal and to improve the reception reliability of the control information.

Effects obtainable in the present disclosure are not limited to the above-mentioned effects, and other effects not mentioned may be clearly understood by those of ordinary skill in the art to which the present disclosure belongs from the description below. will be.

The above and other objects, features and advantages of the present disclosure will become clearer through the following description of embodiments of the present disclosure with reference to the accompanying drawings.

1 is a time-frequency domain of a wireless communication system such as Long Term Evolution (LTE) or Evolved Universal Terrestrial Radio Access (E-UTRA), LTE-Advanced (LTE-A), NR or similar according to an embodiment of the present disclosure; It is a diagram showing the transmission structure.

2 is a view showing a frame, subframe, slot structure in 5G (5 ^th generation), according to one embodiment of the present disclosure.

3 is a diagram illustrating an example of a configuration of a bandwidth part (BWP) in a wireless communication system according to an embodiment of the present disclosure.

4 is a diagram illustrating an example of setting a control region of a downlink control channel in a wireless communication system according to an embodiment of the present disclosure.

5 is a diagram for explaining the structure of a downlink control channel of a wireless communication system according to an embodiment of the present disclosure.

6 is a diagram illustrating an example of PDSCH frequency axis resource allocation in a wireless communication system according to an embodiment of the present disclosure.

7 is a diagram illustrating an example of physical downlink shared channel (PDSCH) time axis resource allocation in a wireless communication system according to an embodiment of the present disclosure.

8 is a diagram illustrating an example of time-base resource allocation according to subcarrier intervals of a data channel and a control channel in a wireless communication system according to an embodiment of the present disclosure.

9 is a diagram illustrating a procedure for beam configuration and activation of a PDCCH according to an embodiment of the present disclosure.

10 is a diagram illustrating a procedure for beam configuration and activation of a PDSCH according to an embodiment of the present disclosure.

11 is a diagram illustrating a radio protocol structure of a base station and a terminal in a single cell, carrier aggregation, and dual connectivity situation according to an embodiment of the present disclosure.

12 is a diagram illustrating an example of an antenna port configuration and resource allocation for cooperative communication according to some embodiments in a wireless communication system according to an embodiment of the present disclosure.

13 is a diagram illustrating an example configuration of downlink control information (DCI) for cooperative communication in a wireless communication system according to an embodiment of the present disclosure.

14 is a diagram illustrating an example of configuring a PDCCH basic beam in consideration of a plurality of TRPs according to an embodiment of the present disclosure.

15 is a diagram illustrating a PDCCH monitoring method in CORESET when configuring a PDCCH basic beam considering a plurality of TRPs according to an embodiment of the present disclosure.

16 is a diagram illustrating a structure of a terminal in a wireless communication system according to an embodiment of the present disclosure.

17 is a diagram illustrating a structure of a base station in a wireless communication system according to an embodiment of the present disclosure.

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

In describing the embodiments, descriptions of technical contents that are well known in the technical field to which the present disclosure pertains and are not directly related to the present disclosure will be omitted. This is to more clearly convey the gist of the present disclosure without obscuring the gist of the present disclosure by omitting unnecessary description.

For the same reason, some components are exaggerated, omitted, or schematically illustrated in the accompanying drawings. In addition, the size of each component does not fully reflect the actual size. In each figure, the same or corresponding elements are assigned the same reference numerals.

Advantages and features of the present disclosure, and a method of achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, it is not limited to the embodiments disclosed below and may be implemented in various different forms, and only the embodiments of the present disclosure allow the present disclosure to be complete, and to those of ordinary skill in the art to which the present disclosure pertains. It is provided to fully understand the scope of the invention, and the present disclosure is only defined by the scope of the claims. Like reference numerals refer to like elements throughout.

At this time, it will be understood that each block of the flowchart diagrams and combinations of the flowchart diagrams may be performed by computer program instructions. These computer program instructions may be embodied in a processor of a general purpose computer, special purpose computer, or other programmable data processing equipment, such that the instructions performed by the processor of the computer or other programmable data processing equipment are not described in the flowchart block(s). It creates a means to perform functions. These computer program instructions may also be stored in a computer-usable or computer-readable memory that may direct a computer or other programmable data processing equipment to implement a function in a particular manner, and thus the computer-usable or computer-readable memory. It may also be possible for the instructions stored in the flow chart block(s) to produce an article of manufacture containing instruction means for performing the function described in the flowchart block(s). The computer program instructions may also be mounted on 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-executed process to create a computer or other programmable data processing equipment. It may also be possible for instructions to perform the processing equipment to provide steps for performing the functions described in the flowchart block(s).

Additionally, each block may represent a module, segment, or portion of code that includes one or more executable instructions for executing specified logical function(s). It should also be noted that in some alternative implementations it is also possible for the functions recited in blocks to occur out of order. For example, two blocks shown one after another may in fact be performed substantially simultaneously, or it may be possible that the blocks are sometimes performed in the reverse order according to a corresponding function.

At this time, the term '~ unit' used in this embodiment means software or hardware components such as FPGA (Field Programmable Gate Array) or ASIC (Application Specific Integrated Circuit), and '~ unit' performs certain roles do. However, '-part' is not limited to software or hardware. The '~ unit' may be configured to reside on an addressable storage medium or may be configured to refresh one or more processors. Accordingly, according to some embodiments, '~ part' refers to components such as software components, object-oriented software components, class components, and task components, processes, functions, properties, and programs. Includes procedures, subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays, and variables. The functions provided in the components and '~ units' may be combined into a smaller number of components and '~ units' or further separated into additional components and '~ units'. In addition, components and '~ units' may be implemented to play one or more CPUs in a device or secure multimedia card. Also, according to some embodiments, '~ unit' may include one or more processors.

Hereinafter, the operating principle of the present disclosure will be described in detail with reference to the accompanying drawings. In the following description of the present disclosure, if it is determined that a detailed description of a related well-known function or configuration may unnecessarily obscure the subject matter of the present disclosure, the detailed description thereof will be omitted. In addition, the terms described below are terms defined in consideration of functions in the present disclosure, which may vary according to intentions or customs of users and operators. Therefore, the definition should be made based on the content throughout this specification. Hereinafter, the base station is a subject performing resource allocation of the terminal, and may be at least one of gNode B, eNode B, Node B, a base station (BS), a radio access unit, a base station controller, or a node on a network. The terminal may include a user equipment (UE), a mobile station (MS), a cellular phone, a smart phone, a computer, or a multimedia system capable of performing a communication function. Of course, it is not limited to the above example. Hereinafter, the present disclosure describes a technique for a terminal to receive broadcast information from a base station in a wireless communication system. The present disclosure relates ^{to a communication technique that converges a 5 th} generation (5G) communication system for supporting a higher data rate after a ^{4 th} generation (4G) system with an Internet of Things (IoT) technology, and a system thereof. The present disclosure provides intelligent services (eg, smart home, smart building, smart city, smart car or connected car, healthcare, digital education, retail business, security and safety related services, etc.) based on 5G communication technology and IoT-related technology. ) can be applied to

A term referring to broadcast information, a term referring to control information, a term related to communication coverage, a term referring to a state change (eg, an event), and network entities used in the following description Terms referring to, terms referring to messages, terms referring to components of an apparatus, and the like are exemplified for convenience of description. Accordingly, the present disclosure is not limited to the terms described below, and other terms having equivalent technical meanings may be used.

For convenience of description below, some terms and names defined in the 3rd generation partnership project long term evolution (3GPP LTE) standard may be used. However, embodiments of the present disclosure are not limited by the terms and names, and may be equally applied to systems conforming to other standards.

A wireless communication system, for example, 3GPP's High Speed Packet Access (HSPA), Long Term Evolution (LTE) or Evolved Universal Terrestrial Radio Access (E-UTRA), LTE-Advanced (LTE-A), LTE-Pro, 3GPP2's High Rate Packet Data (HRPD), UMB (Ultra Mobile Broadband), and IEEE's 802.16e, such as communication standards such as communication standards such as broadband wireless that provides high-speed, high-quality packet data service It is evolving into a communication system.

As a representative example of a broadband wireless communication system, in an LTE system, an Orthogonal Frequency Division Multiplexing (OFDM) scheme is employed in Downlink (DL), and Single Carrier Frequency Division Multiple Access (SC-FDMA) is used in Uplink (UL). ) method is used. Uplink refers to a radio link in which a UE (User Equipment) or MS (Mobile Station) transmits data or control signals to a base station (eNode B, or base station (BS)). It means a wireless link that transmits data or control signals. The multiple access method as described above divides the data or control information of each user by allocating and operating the time-frequency resources to which data or control information is to be transmitted for each user so that they do not overlap each other, that is, orthogonality is established. .

As a future communication system after LTE, that is, the 5G communication system must be able to freely reflect various requirements such as users and service providers, so services that satisfy various requirements must be supported. Services considered for the 5G communication system include Enhanced Mobile BroadBand (eMBB), Massive Machine Type Communication (mMTC), and Ultra Reliability Low Latency Communication (URLLC). etc.

According to some embodiments, the eMBB aims to provide a data transfer rate that is more improved than the data transfer rate supported by the existing LTE, LTE-A, or LTE-Pro. For example, in a 5G communication system, the eMBB must be able to provide a maximum data rate of 20 Gbps in the downlink and a maximum data rate of 10 Gbps in the uplink from the viewpoint of one base station. At the same time, it is necessary to provide an increased user perceived data rate of the terminal. In order to satisfy such a requirement, it is required to improve transmission/reception technology, including a more advanced multi-input multi-output (MIMO) transmission technology. In addition, it is possible to satisfy the data transmission speed required by the 5G communication system by using a frequency bandwidth wider than 20 MHz in a frequency band of 3 to 6 GHz or 6 GHz or more instead of the 2 GHz band used by the current LTE.

At the same time, mMTC is being considered to support application services such as the Internet of Things (IoT) in the 5G communication system. In order to efficiently provide the Internet of Things, mMTC may require large-scale terminal access support, improved terminal coverage, improved battery life, and reduced terminal cost within a cell. Since the Internet of Things is attached to various sensors and various devices to provide communication functions, it must be able to support a large number of terminals (eg, 1,000,000 terminals/km2) within a cell. In addition, since a terminal supporting mMTC is highly likely to be located in a shaded area that a cell cannot cover, such as the basement of a building, due to the characteristics of the service, it may require wider coverage compared to other services provided by the 5G communication system. A terminal supporting mMTC should be configured as a low-cost terminal, and since it is difficult to frequently exchange the battery of the terminal, a very long battery life time may be required.

Finally, in the case of URLLC, as a cellular-based wireless communication service used for a specific purpose (mission-critical), remote control for a robot or a machine, industrial automation, As a service used for unmaned aerial vehicles, remote health care, emergency alerts, etc., it is necessary to provide communication that provides ultra-low latency and ultra-reliability. For example, a service supporting URLLC must satisfy an air interface latency of less than 0.5 milliseconds, and at the same time has a requirement of a packet error rate of 10-5 or less. Therefore, for a service supporting URLLC, the 5G system must provide a smaller Transmit Time Interval (TTI) than other services, and at the same time, a design requirement for allocating a wide resource in a frequency band is required. However, the above-described mMTC, URLLC, and eMBB are only examples of different service types, and the service types to which the present disclosure is applied are not limited to the above-described examples.

The services considered in the above-mentioned 5G communication system should be provided by convergence with each other based on one framework. That is, for efficient resource management and control, it is preferable that each service is integrated and controlled and transmitted as a single system rather than being operated independently.

In addition, although embodiments of the present disclosure are described below using LTE, LTE-A, LTE Pro, or NR systems as an example, embodiments of the present disclosure may be applied to other communication systems having a similar technical background or channel type. In addition, the embodiments of the present disclosure may be applied to other communication systems through some modifications within a range that does not significantly depart from the scope of the present disclosure as judged by a person having skilled technical knowledge.

Hereinafter, a frame structure of a wireless communication system to which embodiments of the present disclosure can be applied (eg, a 5G communication system or an NR communication system) will be described in more detail with reference to the drawings.

1 is a time-frequency domain of a wireless communication system such as Long Term Evolution (LTE) or Evolved Universal Terrestrial Radio Access (E-UTRA), LTE-Advanced (LTE-A), NR or similar according to an embodiment of the present disclosure; It is a diagram showing the transmission structure.

Referring to FIG. 1 , in FIG. 1 , the horizontal axis represents the time domain, and the vertical axis represents the frequency domain. In the time and frequency domain, the basic unit of a resource is a resource element (Resource Element, RE, 1-01) as 1 OFDM (Orthogonal Frequency Division Multiplexing) symbol (1-02) on the time axis and 1 subcarrier on the frequency axis (Subcarrier) ( 1-03) can be defined. in the frequency domain

(for example, 12) consecutive REs may constitute one resource block (Resource Block, RB, 1-04). In one embodiment, a plurality of OFDM symbols may constitute one subframe (One subframe, 1-10).

2 is a view showing a frame, subframe, slot structure in 5G (5 ^th generation), according to one embodiment of the present disclosure.

Referring to FIG. 2 , one frame (Frame, 2-00) is composed of one or more subframes (Subframe, 2-01), and one subframe is composed of one or more slots (Slot, 2-02). can For example, one frame (2-00) may be defined as 10 ms. One subframe 2-01 may be defined as 1 ms, and in this case, one frame 2-00 may consist of a total of 10 subframes 2-01. One slot (2-02, 2-03) may be defined as 14 OFDM symbols (that is, the number of symbols per slot (

)=14). One subframe (2-01) may consist of one or a plurality of slots (2-02, 2-03), and the number of slots (2-02, 2-03) per one subframe (2-01) may be different depending on the set value μ(2-04, 2-05) for the subcarrier spacing. In an example of FIG. 2 , a case of μ=0 (2-04) and a case of μ=1 (2-05) are illustrated as subcarrier spacing setting values. When μ = 0 (2-04), one subframe (2-01) may consist of one slot (2-02), and when μ = 1 (2-05), one subframe (2) -01) may consist of two slots 2-03. That is, the number of slots per subframe (

) may vary, and accordingly, the number of slots per frame (

) may be different. According to each subcarrier spacing setting μ

and

may be defined as in [Table 1] below.

μ
0	14	10	One
One	14	20	2
2	14	40	4
3	14	80	8
4	14	160	16
5	14	320	32

In NR, one component carrier (CC) or serving cell may be configured with up to 250 or more RBs. Therefore, when the terminal always receives the entire serving cell bandwidth (serving cell bandwidth) like LTE, the power consumption of the terminal may be extreme, and in order to solve this, the base station sets one or more bandwidth parts (BWP) to the terminal Thus, it is possible to support the UE to change the reception area within the cell. In NR, the base station may set 'initial BWP', which is the bandwidth of CORESET #0 (or common search space, CSS), to the terminal through a master information block (MIB). Thereafter, the base station may set the initial BWP (first BWP) of the terminal through RRC signaling, and notify at least one or more BWP configuration information that may be indicated through future downlink control information (DCI). Thereafter, the base station may indicate which band the terminal uses by announcing the BWP ID through DCI. If the UE does not receive DCI in the currently allocated BWP for a specific time or longer, the UE returns to the 'default BWP' and attempts to receive DCI.

3 is a diagram illustrating an example of a configuration of a bandwidth part (BWP) in a wireless communication system according to an embodiment of the present disclosure.

Referring to FIG. 3 , FIG. 3 shows an example in which the terminal bandwidth 3-00 is set to two bandwidth parts, that is, a bandwidth part #1(3-05) and a bandwidth part #2(3-10). The base station may set one or more bandwidth portions to the terminal, and may set information as shown in [Table 2] below for each bandwidth portion.

BWP ::= SEQUENCE { bwp-ID BWP-Id, (bandwidth part identifier) locationAndBandwidth INTEGER (1..65536), (Bandwidth part location) subcarrierSpacing ENUMERATED {n0, n1, n2, n3, n4, n5 }, (subcarrier spacing) cyclicPrefix ENUMERATED { extended } (circular transposition) }

Of course, it is not limited to the above-described example, and in addition to the above-described configuration information, various parameters related to the bandwidth portion may be set in the terminal. The above-described information may be transmitted by the base station to the terminal through higher layer signaling, for example, RRC signaling. At least one bandwidth part among the set one or a plurality of bandwidth parts may be activated. Whether to activate the set bandwidth portion may be semi-statically transmitted from the base station to the terminal through RRC signaling, or may be dynamically transmitted through a MAC control element (MAC CE) or DCI.

According to an embodiment of the present disclosure, the terminal before the RRC (Radio Resource Control) connection may receive an initial bandwidth part (Initial BWP) for the initial connection from the base station through the MIB (Master Information Block). More specifically, in order for the terminal to receive the system information (Remaining System Information; RMSI or System Information Block 1; may correspond to SIB1) necessary for initial access through the MIB in the initial access step, the PDCCH can be transmitted. It is possible to receive setting information for a control resource set (CORESET) and a search space (Search Space). The control region and the search space set by the MIB may be regarded as identifier (Identity, ID) 0, respectively.

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 through the MIB. In addition, the base station may notify the UE of configuration information on the monitoring period and occasion for the control region #0, that is, configuration information on the search space #0 through the MIB. The UE may regard the frequency domain set as the control region #0 obtained from the MIB as an initial bandwidth part for initial access. In this case, the identifier (ID) of the initial bandwidth part may be regarded as 0.

On the other hand, the configuration of the bandwidth part supported by the wireless communication system (eg, 5G or NR system) to which the present disclosure can be applied may be used for various purposes.

For example, when the bandwidth supported by the terminal is smaller than the system bandwidth, the bandwidth supported by the terminal may be supported by setting the bandwidth portion. For example, in <Table 2>, the frequency position (setting information 2) of the bandwidth part is set for the terminal, so that the terminal can transmit and receive data at a specific frequency position within the system bandwidth.

As another example, for the purpose of supporting different numerologies, the base station may configure a plurality of bandwidth portions for the terminal. For example, in order to support both data transmission and reception using a subcarrier interval of 15 kHz and a subcarrier interval of 30 kHz to an arbitrary terminal, two bandwidth portions may be set to use a subcarrier interval of 15 kHz and 30 kHz, respectively. Different bandwidth portions may be subjected to frequency division multiplexing (FDM), and when data is transmitted/received at a specific subcarrier interval, a bandwidth portion set for the corresponding subcarrier interval may be activated.

As another example, for the purpose of reducing power consumption of the terminal, the base station may set bandwidth portions having different sizes of bandwidths to the terminal. For example, when the terminal supports a very large bandwidth, for example, a bandwidth of 100 MHz and always transmits/receives data using the corresponding bandwidth, very large power consumption may be caused. In particular, it is very inefficient in terms of power consumption for the UE to monitor an unnecessary downlink control channel for a large bandwidth of 100 MHz in a situation in which there is no traffic. Therefore, for the purpose of reducing power consumption of the terminal, the base station may configure a relatively small bandwidth portion of the terminal, for example, a bandwidth portion of 20 MHz. In the absence of traffic, the UE may perform a monitoring operation in the 20 MHz bandwidth portion, and when data is generated, it may transmit/receive data using the 100 MHz bandwidth portion according to the instruction of the base station.

In the method of setting the bandwidth part, terminals before RRC connection (Connected) may receive configuration information on the initial bandwidth part through a master information block (MIB) in the initial access stage. More specifically, the UE is a control region for a downlink control channel through which Downlink Control Information (DCI) for scheduling a System Information Block (SIB) can be transmitted from the MIB of a Physical Broadcast Channel (PBCH) (or a control resource set, Control Resource Set, CORESET) can be set. The bandwidth of the control region set as the MIB may be regarded as an initial bandwidth part, and the terminal may receive the PDSCH through which the SIB is transmitted through the set initial bandwidth part. In addition to the purpose of receiving the SIB, the initial bandwidth part may be utilized for other system information (OSI), paging, and random access.

Hereinafter, a synchronization signal (SS)/PBCH block (SSB) of a wireless communication system (5G or NR system) to which the present disclosure can be applied will be described.

The SS/PBCH block may mean a physical layer channel block composed of a primary SS (PSS), a secondary SS (SSS), and a PBCH. More specifically, the SS/PBCH block may be defined as follows.

- PSS: A signal that serves as a reference for downlink time/frequency synchronization and may provide some information on cell ID.

- SSS: serves as a reference for downlink time/frequency synchronization, and may provide the remaining cell ID information not provided by PSS. Additionally, it may serve as a reference signal for demodulation of the PBCH.

- PBCH: It is possible to provide essential system information necessary for transmitting and receiving a data channel and a control channel of the terminal. The essential system information may include search space-related control information indicating radio resource mapping information of a control channel, scheduling control information on a separate data channel for transmitting system information, and the like.

- SS/PBCH block: The SS/PBCH block may consist of a combination of PSS, SSS, and PBCH. One or a plurality of SS/PBCH blocks may be transmitted within 5 ms, and each transmitted SS/PBCH block may be distinguished by an index.

The UE may detect the PSS and SSS in the initial access stage and may decode the PBCH. The UE may obtain the MIB from the PBCH, and may receive the control region #0 configured through the MIB. The UE may perform monitoring on the control region #0, assuming that the selected SS/PBCH block and the DMRS (Reference Signal) transmitted in the control region #0 are QCL (Quasi Co Location). System information may be received through downlink control information transmitted in region #0. The UE may obtain RACH (Random Access Channel) related configuration information required for initial access from the received system information. In consideration of the PBCH index, PRACH (Physical RACH) may be transmitted to the base station, and the base station receiving the PRACH may obtain information on the SS/PBCH block index selected by the UE. It can be seen that a certain block is selected from among them, and the UE monitors the control region #0 corresponding to (or associated with) the selected SS/PBCH block.

Hereinafter, downlink control information (hereinafter referred to as DCI) in a wireless communication system (5G or NR system) to which the present disclosure can be applied will be described in detail.

Uplink data (or physical uplink data channel (Physical Uplink Shared Channel, PUSCH)) or downlink data (or physical downlink data channel (Physical Downlink Shared Channel, PDSCH)) in a next-generation mobile communication system (5G or NR system) Scheduling information may be transmitted from the base station to the terminal through DCI. The UE may monitor the DCI format for fallback and the DCI format for non-fallback for PUSCH or PDSCH. The fallback DCI format may consist of a fixed field predetermined between the base station and the terminal, and the non-fallback DCI format may include a configurable field.

DCI may be transmitted through a physical downlink control channel (PDCCH), which is a physical downlink control channel, through a channel coding and modulation process. A cyclic redundancy check (CRC) may be attached 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. Depending on the purpose of the DCI message, for example, UE-specific data transmission, power control command, or random access response, different RNTIs may be used for scrambling of the CRC attached to the payload of the DCI message. That is, the RNTI may not be explicitly transmitted, but may be transmitted while being included in the CRC calculation process. When the DCI message transmitted on the PDCCH is received, the UE may check the CRC using the allocated RNTI. If the CRC check result is correct, the terminal can know that the corresponding message has been transmitted to the terminal.

For example, DCI scheduling PDSCH for system information (SI) may be scrambled with SI-RNTI. DCI scheduling a PDSCH for a random access response (RAR) message may be scrambled with an RA-RNTI. DCI scheduling a PDSCH for a paging message may be scrambled with a P-RNTI. DCI notifying SFI (Slot Format Indicator) may be scrambled with SFI-RNTI. DCI notifying Transmit Power Control (TPC) may be scrambled with TPC-RNTI. DCI for scheduling UE-specific PDSCH or PUSCH may be scrambled with C-RNTI (Cell RNTI).

DCI format 0_0 may be used as a fallback DCI for scheduling PUSCH, and in this case, CRC may be scrambled with C-RNTI. In an embodiment, DCI format 0_0 in which CRC is scrambled with C-RNTI may include information as shown in [Table 3] below.

- Identifier for DCI formats - [1] bit - Frequency domain resource assignment - [ ] bits - Time domain resource assignment - X bits - Frequency hopping flag - 1 bit - Modulation and coding scheme - 5bits - New data indicator - 1 bit - Redundancy version - 2bits - HARQ process number (HARQ process number) - 4 bits - TPC command for scheduled PUSCH (transmit power control command for scheduled PUSCH - [2] bits - UL / SUL indicator (uplink / additional uplink (supplementary UL) indicator) - 0 or 1 bit

DCI format 0_1 may be used as a non-fallback DCI for scheduling PUSCH, and in this case, CRC may be scrambled with C-RNTI. In an embodiment, DCI format 0_1 in which CRC is scrambled with C-RNTI may include information as shown in [Table 4] below.

- Carrier indicator - 0 or 3 bits - UL/SUL indicator - 0 or 1bit - Identifier for DCI formats - [1] bits - Bandwidth part indicator - 0, 1, or 2 bits - Frequency domain resource assignment ● For resource allocation type 0 (for resource allocation type 0), bits ● For resource allocation type 1 (for resource allocation type 1), bits - Time domain resource assignment - 1, 2, 3, or 4 bits - VRB-to-PRB mapping (virtual resource block-to-physical resource block mapping)- 0 or 1 bit, only for resource allocation type 1. ● 0 bit if only resource allocation type 0 is configured; ● 1 bit otherwise. - Frequency hopping flag - 0 or 1 bit, only for resource allocation type 1. ● 0 bit if only resource allocation type 0 is configured; ● 1 bit otherwise. - Modulation and coding scheme - 5 bits - New data indicator - 1bit - Redundancy version - 2 bits - HARQ process number - 4 bits - 1st downlink assignment index (first downlink assignment index) - 1 or 2 bits ● 1 bit for semi-static HARQ-ACK codebook (in case of semi-static HARQ-ACK codebook); ● 2 bit for dynamic HARQ-ACK codebook with single HARQ-ACK codebook (when dynamic HARQ-ACK codebook is used together with single HARQ-ACK codebook). - 2nd downlink assignment index (second downlink assignment index) - 0 or 2 bits ● 2 bits for dynamic HARQ-ACK codebook with two HARQ-ACK sub-codebooks (when dynamic HARQ-ACK codebook is used together with two HARQ-ACK sub-codebooks); ● 0 bit otherwise. - TPC command for scheduled PUSCH - 2 bits - SRS resource indicator - or bits ● bits for non-codebook based PUSCH transmission ● bits for codebook based PUSCH transmission - Precoding information and number of layers-up to 6 bits - Antenna ports - up to 5 bits - SRS request - 2 bits - CSI request (channel state information request) - 0, 1, 2, 3, 4, 5, or 6 bits - CBG transmission information (code block group transmission information) - 0 2, 4, 6, or 8 bits - PTRS-DMRS association (phase tracking reference signal - demodulation reference signal relationship) - 0 or 2 bits - beta_offset indicator - 0 or 2 bits - DMRS sequence initialization - 0 or 1 bit

DCI format 1_0 may be used as a fallback DCI for scheduling PDSCH, and in this case, CRC may be scrambled with C-RNTI. In an embodiment, DCI format 1_0 in which CRC is scrambled with C-RNTI may include information as shown in [Table 5] below.

- Identifier for DCI formats - [1] bit - Frequency domain resource assignment - [ ] bits - Time domain resource assignment - X bits - VRB-to-PRB mapping - 1 bit. - Modulation and coding scheme - 5 bits - New data indicator - 1 bit - Redundancy version - 2 bits - HARQ process number - 4 bits - Downlink assignment index - 2 bits - TPC command for scheduled PUCCH - [2] bits - PUCCH resource indicator (physical uplink control channel, PUCCH) resource indicator - 3 bits - PDSCH-to-HARQ feedback timing indicator (PDSCH-to-HARQ feedback timing indicator - [3] bits

Alternatively, DCI format 1_0 may be used as DCI for scheduling PDSCH for RAR message, and in this case, CRC may be scrambled with RA-RNTI. DCI format 1_0 in which CRC is scrambled with C-RNTI may include information as shown in [Table 6] below.

- Frequency domain resource assignment - bits - Time domain resource assignment - 4 bits - VRB-to-PRB mapping - 1 bit - Modulation and coding scheme - 5 bits - TB scaling - 2 bits - Reserved bits - 16 bits

DCI format 1_1 may be used as a non-fallback DCI for scheduling PDSCH, and in this case, CRC may be scrambled with C-RNTI. In an embodiment, DCI format 1_1 in which CRC is scrambled with C-RNTI may include information as shown in [Table 7] below.

- Carrier indicator - 0 or 3 bits - Identifier for DCI formats - [1] bits - Bandwidth part indicator - 0, 1 or 2 bits - Frequency domain resource assignment ● For resource allocation type 0, bits ● For resource allocation type 1, bits - Time domain resource assignment - 0, 1, 2, 3, or 4 bits - VRB-to-PRB mapping - 0 or 1 bit: ● 0 bit if only resource allocation type 0 is configured; ● 1 bit otherwise. - PRB bundling size indicator (physical resource block bundling size indicator) - 0 or 1 bit - Rate matching indicator - 0, 1, or 2 bits - ZP CSI-RS trigger (zero power channel state information reference signal trigger) - 0, 1, or 2 bits For transport block 1 (for the first transport block): - Modulation and coding scheme - 5 bits - New data indicator - 1 bit - Redundancy version - 2 bits For transport block 2 (for the second transport block): - Modulation and coding scheme - 5 bits - New data indicator - 1 bit - Redundancy version - 2 bits - HARQ process number - 4 bits - Downlink assignment index - 0 or 2 or 4 bits - TPC command for scheduled PUCCH - 2 bits - PUCCH resource indicator - 3 bits - PDSCH-to-HARQ_feedback timing indicator - 3bits - Antenna ports - 4, 5 or 6 bits - Transmission configuration indication - 0 or 3 bits - SRS request - 2 bits - CBG transmission information - 0, 2, 4, 6, or 8 bits - CBG flushing out information (code block group flushing out information) - 0 or 1 bit - DMRS sequence initialization - 1 bit

4 is a diagram illustrating an example of setting a control region of a downlink control channel in a wireless communication system according to an embodiment of the present disclosure.

Specifically, FIG. 4 is a diagram illustrating an embodiment of a control region (Control Resource Set, CORESET) through which a downlink control channel is transmitted in a wireless communication system according to an embodiment of the present disclosure.

Referring to FIG. 4, FIG. 4 shows two control regions (control region #1 (4-01) in one slot (4-20) on a time axis and a bandwidth part (UE bandwidth part) of the terminal on the frequency axis (4-10). ), control area #2 (4-02)) is set. The control regions 4-01 and 4-02 may be set in a specific frequency resource 4-03 within the entire terminal bandwidth part 4-10 on the frequency axis. The control regions 4-01 and 4-02 may be set with one or a plurality of OFDM symbols on the time axis, which may be defined as a control region length (Control Resource Set Duration, 4-04). Referring to FIG. 4 , the control region #1 (4-01) may be set to a control region length of 2 symbols, and the control region #2 (4-02) may be set to a control region length of 1 symbol.

Meanwhile. A control region in a wireless communication system (5G or NR system) to which the present disclosure can be applied, the base station provides upper layer signaling to the terminal (eg, system information (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 identifier (Identity), a frequency position of the control region, and a symbol length of the control region. For example, the setting of the control area may include information as shown in [Table 8] below.

ControlResourceSet ::= SEQUENCE { -- Corresponds to L1 parameter 'CORESET-ID' controlResourceSetId ControlResourceSetId, {control area identifier (Identity)} frequencyDomainResources BIT STRING (SIZE (45)), (frequency axis resource allocation information) duration INTEGER (1..maxCoReSetDuration), (Time axis resource allocation information) cce-REG-MappingType CHOICE { (CCE-to-REG mapping method) interleaved SEQUENCE { reg-BundleSize ENUMERATED {n2, n3, n6}, (REG bundle size) precoderGranularity ENUMERATED {sameAsREG-bundle, allContiguousRBs}, interleaverSize ENUMERATED {n2, n3, n6}, (interleaver size) shiftIndex INTEGER (0..maxNrofPhysicalResourceBlocks-1) (Interleaver Shift) }, nonInterleaved NULL }, tci-StatesPDCCH SEQUENCE (SIZE (1..maxNrofTCI-StatesPDCCH)) OF TCI-StateId OPTIONAL, (QCL setting information) tci-PresentInDCI ENUMERATED {enabled} }

In [Table 8], tci-StatesPDCCH (hereinafter referred to as 'TCI state') configuration information is one or a plurality of SSs (Synchronization) that are in a Quasi Co Located (QCL) relationship with DMRS (Demodulation Reference Signal) transmitted in the corresponding control region. Signal)/Physical Broadcast Channel (PBCH) block index or CSI-RS (Channel State Information Reference Signal) index information.

In a wireless communication system, one or more different antenna ports (or one or more channels, signals, and combinations thereof may be replaced, but in the description of the present disclosure in the future, for convenience, different antenna ports will be referred to) They may be associated with each other by QCL settings as shown in [Table 9] below.

QCL-Info ::= SEQUENCE { cell ServCellIndex (Serving cell index to which QCL reference RS is transmitted) bwp-Id BWP-Id (bandwidth partial index over which QCL reference RS is transmitted) referenceSignal CHOICE {(Indicator indicating one of CSI-RS or SS/PBCH block as QCL reference RS) csi-rs NZP-CSI-RS-ResourceId, ssb SSB-Index }, qcl-Type ENUMERATED {typeA, typeB, typeC, type D}, (QCL type indicator) ... }

Specifically, the QCL setting can connect two different antenna ports (QCL) in a relationship between a target antenna port and a (QCL) reference antenna port, and the terminal can perform statistical characteristics (eg, For example, all or part of the large scale parameters of the channel such as Doppler shift, Doppler spread, average delay, delay spread, average gain, and spatial Rx (or Tx) parameters or the reception spatial filter coefficient or transmission spatial filter coefficient of the terminal) are set to the target antenna port. It can be applied (or assumed) upon reception. In the above, the target antenna port refers to an antenna port for transmitting a channel or signal set by a higher layer setting including the QCL setting, or an antenna port for transmitting a channel or signal to which a TCI state indicating the QCL setting is applied. can In the above, the reference antenna port may mean an antenna port for transmitting a channel or signal indicated (specific) by the referenceSignal parameter in the QCL configuration.

Specifically, the statistical characteristics of the channel defined by the QCL setting (indicated by the parameter qcl-Type in the QCL setting) may be classified according to the QCL type as follows.

* 'QCL-TypeA': {Doppler shift, Doppler spread, average delay, delay spread}

* 'QCL-TypeB': {Doppler shift, Doppler spread}

* 'QCL-TypeC': {Doppler shift, average delay}

* 'QCL-TypeD': {Spatial Rx parameter}

At this time, the types of QCL type are not limited to the above four types, but all possible combinations are not listed in order not to obscure the gist of the description. In the above, QCL-TypeA indicates that the bandwidth and transmission period of the target antenna port are both sufficient compared to the reference antenna port (that is, the number of samples and the transmission band/time of the target antenna port on both the frequency axis and the time axis are the number of samples and transmission of the reference antenna port. More than band/time) This is a QCL type used when all statistical properties that can be measured in frequency and time axes can be referenced. QCL-TypeB is a QCL type used when the bandwidth of the target antenna port is sufficient to measure measurable statistical characteristics on the frequency axis, that is, Doppler shift and Doppler spreads. QCL-TypeC is a QCL type used when the bandwidth and transmission period of the target antenna port are insufficient to measure second-order statistics, that is, Doppler spread and delay spreads, so that only first-order statistics, that is, Doppler shift and average delay, can be referred to. . QCL-TypeD is a QCL type set when spatial reception filter values used when receiving a reference antenna port can be used when receiving a target antenna port.

On the other hand, it is possible for the base station to set or instruct up to two QCL settings to one target antenna port through the TCI state setting as shown in Table 10 below.

TCI-State ::= SEQUENCE { tci-StateId TCI-StateID, (TCI state indicator) qcl-Type1 QCL-Info, (Set the first QCL for the target antenna port to which the TCI state is applied) qcl-Type2 QCL-Info (Set the second QCL for the target antenna port to which the TCI state is applied) OPTIONAL, --Need R ... }

Among the two QCL settings included in one TCI state setting, the first QCL setting may be set to one of QCL-TypeA, QCL-TypeB, and QCL-TypeC. In this case, the settable QCL type is specified according to the types of the target antenna port and the reference antenna port, and will be described in detail below. In addition, the second QCL setting among the two QCL settings included in the one TCI state setting may be set to QCL-TypeD, and may be omitted in some cases.

Tables 11 to 15 below are tables showing valid TCI state settings according to target antenna port types.

Table 11 shows the valid TCI state configuration when the target antenna port is CSI-RS for tracking (TRS). The TRS refers to an NZP CSI-RS in which a repetition parameter is not set among CSI-RSs and trs-Info is set to true. In the case of setting 3 in Table 11, it can be used for aperiodic TRS.

[Table 11] Valid TCI state setting when the target antenna port is CSI-RS for tracking (TRS)

Valid TCI state Configuration	DL RS1	qcl-Type1	DL RS2 (if configured)	qcl-Type2 (if configured)
One	SSB	QCL-TypeC	SSB	QCL-TypeD
2	SSB	QCL-TypeC	CSI-RS (BM)	QCL-TypeD
3	TRS (periodic)	QCL-TypeA	TRS (same as DL RS1)	QCL-TypeD

Table 12 shows the valid TCI state configuration when the target antenna port is CSI-RS for CSI. The CSI-RS for CSI means an NZP CSI-RS in which the repetition parameter is not set and trs-Info is not set to true among the CSI-RSs.

[Table 12] Valid TCI state setting when the target antenna port is CSI-RS for CSI

Valid TCI state Configuration	DL RS1	qcl-Type1	DL RS2 (if configured)	qcl-Type2 (if configured)
One	TRS	QCL-TypeA	SSB	QCL-TypeD
2	TRS	QCL-TypeA	CSI-RS (BM)	QCL-TypeD
3	TRS	QCL-TypeA	TRS (same as DL RS1)	QCL-TypeD
4	TRS	QCL-TypeB

Table 13 shows the effective TCI state configuration when the target antenna port is CSI-RS for beam management (BM, the same meaning as CSI-RS for L1 RSRP reporting). The CSI-RS for BM means an NZP CSI-RS in which a repetition parameter is set among CSI-RSs, has a value of On or Off, and trs-Info is not set to true.

[Table 13] Valid TCI state configuration when the target antenna port is CSI-RS for BM (for L1 RSRP reporting)

Valid TCI state Configuration	DL RS1	qcl-Type1	DL RS2 (if configured)	qcl-Type2 (if configured)
One	TRS	QCL-TypeA	TRS (same as DL RS1)	QCL-TypeD
2	TRS	QCL-TypeA	CSI-RS (BM)	QCL-TypeD
3	SS/PBCHBlock	QCL-TypeC	SS/PBCH Block	QCL-TypeD

Table 14 shows the valid TCI state configuration when the target antenna port is a PDCCH DMRS.

[Table 14] Valid TCI state setting when target antenna port is PDCCH DMRS

Valid TCI state Configuration	DL RS1	qcl-Type1	DL RS2 (if configured)	qcl-Type2 (if configured)
One	TRS	QCL-TypeA	TRS (same as DL RS1)	QCL-TypeD
2	TRS	QCL-TypeA	CSI-RS (BM)	QCL-TypeD
3	CSI-RS (CSI)	QCL-TypeA	CSI-RS (same as DL RS1)	QCL-TypeD

Table 15 shows the valid TCI state configuration when the target antenna port is a PDSCH DMRS.

[Table 15] Valid TCI state setting when target antenna port is PDSCH DMRS

Valid TCI state Configuration	DL RS1	qcl-Type1	DL RS2 (if configured)	qcl-Type2 (if configured)
One	TRS	QCL-TypeA	TRS	QCL-TypeD
2	TRS	QCL-TypeA	CSI-RS (BM)	QCL-TypeD
3	CSI-RS (CSI)	QCL-TypeA	CSI-RS (CSI)	QCL-TypeD

In the representative QCL setting method according to Tables 11 to 15, the target antenna port and the reference antenna port for each step are set to "SSB" -> "TRS" -> "CSI-RS for CSI, or CSI-RS for BM, or PDCCH DMRS. , or PDSCH DMRS". Through this, it is possible to link the statistical characteristics that can be measured from the SSB and the TRS to each antenna port to help the reception operation of the terminal.

5 is a diagram for explaining the structure of a downlink control channel of a wireless communication system according to an embodiment of the present disclosure.

Specifically, FIG. 5 is a diagram illustrating an example of a basic unit of time and frequency resources constituting a downlink control channel that can be used in 5G according to an embodiment of the present disclosure.

Referring to FIG. 5 , a basic unit of time and frequency resources constituting a control channel may be defined as a resource element group (REG) 503 . The REG 503 may be defined as 1 OFDM symbol 501 on the time axis and 1 Physical Resource Block (PRB) 502 on the frequency axis, that is, 12 subcarriers. The base station may configure a downlink control channel allocation unit by concatenating the REG 503 .

As shown in FIG. 5 , when a basic unit to which a downlink control channel is allocated in 5G is referred to as a control channel element (CCE), one CCE 504 may be composed of a plurality of REGs 503 . For example, the REG 503 shown in FIG. 5 may be composed of 12 REs, and if 1 CCE 504 is composed of 6 REGs 503, 1 CCE 504 is composed of 72 REs. can When a downlink control region is set, the corresponding region may be composed of a plurality of CCEs 504, and a specific downlink control channel is configured with one or a plurality of CCEs 504 according to an aggregation level (AL) in the control region. It can be mapped and transmitted. The CCEs 504 in the control region are divided by numbers, and in this case, the numbers of the CCEs 5-04 may be assigned according to a logical mapping method.

The basic unit of the downlink control channel shown in FIG. 5 , that is, the REG 503 , may include both REs to which DCI is mapped and a region to which the DMRS 505 , which is a reference signal for decoding them, is mapped. As in FIG. 5 , three DMRSs 505 may be transmitted within one REG 503 . The number of CCEs required to transmit the PDCCH may be 1, 2, 4, 8, or 16 according to an aggregation level (AL), and the number of different CCEs is the link adaptation of the downlink control channel. can be used to implement For example, when AL=L, one downlink control channel may be transmitted through L CCEs.

The UE needs to detect a signal without knowing the information on the downlink control channel. For blind decoding, a search space representing a set of CCEs may be defined. The search space is a set of downlink control channel candidates consisting of CCEs that the UE should attempt to decode on a given aggregation level. Since there are various aggregation levels that make one bundle with 1, 2, 4, 8, and 16 CCEs, the UE may have a plurality of search spaces. A search space set may be defined as a set of search spaces in all set aggregation levels.

The search space may be classified into a common search space and a UE-specific search space. According to an embodiment of the present disclosure, a group of terminals or all terminals may search the common search space of the PDCCH in order to receive cell-common control information such as dynamic scheduling for system information or a paging message.

For example, the UE may receive PDSCH scheduling assignment information for transmission of SIB including operator information of a cell by examining the common search space of the PDCCH. In the case of the common search space, since a certain group of terminals or all terminals must receive the PDCCH, the common search space may be defined as a set of predefined CCEs. Meanwhile, the UE may receive scheduling assignment information for UE-specific PDSCH or PUSCH by examining UE-specific search space of PDCCH. The UE-specific search space may be UE-specifically defined as a function of the UE's identity and various system parameters.

On the other hand, in a wireless communication system (5G or NR system) to which the present disclosure can be applied, the parameter for the search space for the PDCCH may be set from the base station to the terminal by higher layer signaling (eg, SIB, MIB, RRC signaling). For example, the base station is the number of PDCCH candidates in each aggregation level L, the monitoring period for the search space, the monitoring occasion in symbol units in the slot for the search space, the search space type (common search space or terminal-specific search space), A combination of DCI format and RNTI to be monitored in the corresponding search space, a control region index to be monitored in the search space, etc. may be set to the UE. For example, the setting may include information as shown in [Table 16] below.

SearchSpace ::= SEQUENCE { -- Identity of the search space. SearchSpaceId = 0 identifies the SearchSpace configured via PBCH (MIB) or ServingCellConfigCommon. searchSpaceId SearchSpaceId, (search space identifier) controlResourceSetId ControlResourceSetId, (control area identifier) monitoringSlotPeriodicityAndOffset CHOICE { (Monitoring slot level cycle) s11 NULL, s12 INTEGER (0..1), s14 INTEGER (0..3), s15 INTEGER (0..4), s18 INTEGER (0..7), s110 INTEGER (0..9) s116 INTEGER (0..15), s120 INTEGER (0..19) } duration (monitoring length) INTEGER (2.2.2559) monitoringSymbolsWithinSlot BIT STRING (SIZE (14)) (Monitoring symbol in slot) nrofCandidates SEQUENCE { (Number of PDCCH candidates by aggregation level) aggregationLevel1 ENUMERATED {n0, n1, n2, n3, n4, n5, n6, n8}, aggregationLevel2 ENUMERATED {n0, n1, n2, n3, n4, n5, n6, n8}, aggregationLevel4 ENUMERATED {n0, n1, n2, n3, n4, n5, n6, n8}, aggregationLevel8 ENUMERATED {n0, n1, n2, n3, n4, n5, n6, n8}, aggregationLevel16 ENUMERATED {n0, n1, n2, n3, n4, n5, n6, n8} }, searchSpaceType CHOICE { (Search space type) -- Configures this search space as common search space (CSS) and DCI formats to monitor. common SEQUENCE { (Common Search Space) } ue-specific SEQUENCE { (terminal-specific search space) -- Indicates whether the UE monitors in this USS for DCI formats 0-0 and 1-0 or for formats 0-1 and 1-1. formats ENUMERATED {formats 0-0-And-1-0, formats 0-1-And-1-1}, ... }

Based on the configuration information, the base station may configure one or a plurality of search space sets for the terminal. According to an embodiment of the present disclosure, the base station may set the search space set 1 and the search space set 2 to the terminal, and the DCI format A scrambled with X-RNTI in the search space set 1 may be configured to be monitored in the common search space. and DCI format B scrambled with Y-RNTI in search space set 2 may be configured to be monitored in a UE-specific search space.

According to the configuration information, one or a plurality of search space sets may exist 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.

The common search space may be classified into a search space set of a specific type according to a purpose. An RNTI to be monitored may be different for each type of a determined search space set. For example, the common search space type, purpose, and RNTI to be monitored can be classified as shown in Table 17 below.

Search space type	purpose	RNTI
Type0 CSS	PDCCH transmission for SIB schedule	SI-RNTI
Type0A CSS	PDCCH transmission for SI schedules other than SIB1 (SIB2, etc.)	SI-RNTI
Type1 CSS	PDCCH transmission for random access response (RAR) schedule, Msg3 retransmission schedule, and Msg4 schedule	RA-RNTI, TC-RNTI
Type2 CSS	paging	P-RNTI
Type3 CSS	Send group control information	INT-RNTI, SFI-RNTI, TPC-PUSCH-RNTI, TPC-PUCCH-RNTI, TPC-SRS-RNTI
	In case of PCell, PDCCH transmission for data schedule	C-RNTI, MCS-C-RNTI, CS-RNTI

Meanwhile, in the common search space, a combination of the following DCI format and RNTI may be monitored. Of course, it is not limited to the following examples.

- 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

- DCI format 2_0 with CRC scrambled by SFI-RNTI

- DCI format 2_1 with CRC scrambled by INT-RNTI

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

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

In the UE-specific search space, a combination of the following DCI format and RNTI may be monitored. Of course, it is not limited to the following examples.

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

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

On the other hand, the specified RNTIs may follow the following definitions and uses.

C-RNTI (Cell RNTI): UE-specific PDSCH scheduling purpose

TC-RNTI (Temporary Cell RNTI): UE-specific PDSCH scheduling purpose

CS-RNTI (Configured Scheduling RNTI): Semi-statically configured UE-specific PDSCH scheduling purpose

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

P-RNTI (Paging RNTI): PDSCH scheduling purpose for which paging is transmitted

SI-RNTI (System Information RNTI): PDSCH scheduling purpose in which system information is transmitted

INT-RNTI (Interruption RNTI): Used to inform whether pucturing for PDSCH

TPC-PUSCH-RNTI (Transmit Power Control for PUSCH RNTI): Used to indicate power control command for PUSCH

Transmit Power Control for PUCCH RNTI (TPC-PUCCH-RNTI): Used to indicate power control command for PUCCH

Transmit Power Control for SRS RNTI (TPC-SRS-RNTI): For instructing power control commands for SRS

In an embodiment, the above-described DCI formats may be defined as shown in [Table 18] below.

DCI format	Usage
0_0	Scheduling of PUSCH in one cell
0_1	Scheduling of PUSCH in one cell
1_0	Scheduling of PDSCH in one cell
1_1	Scheduling of PDSCH in one cell
2_0	Notifying a group of UEs of the slot format
2_1	Notifying a group of UEs of the PRB(s) and OFDM symbol(s) where UE may assume no transmission is intended for the UE
2_2	Transmission of TPC commands for PUCCH and PUSCH
2_3	Transmission of a group of TPC commands for SRS transmission by one or more UEs

In a wireless communication system (5G system or NR system) to which the present disclosure can be applied, a plurality of search space sets may be set with different parameters (eg, parameters in [Table 10]). Accordingly, the set of search space sets monitored by the terminal at every time point may be different. For example, if the search space set #1 is set to the X-slot period, the search space set #2 is set to the Y-slot period and X and Y are different, the UE searches with the search space set #1 in a specific slot. All of the space set #2 can be monitored, and one of the search space set #1 and the search space set #2 can be monitored in a specific slot.

When a plurality of search space sets are configured for the terminal, the following conditions may be considered in order to determine the search space set to be monitored by the terminal.

[Condition 1: Limit the maximum number of PDCCH candidates]

The number of PDCCH candidates that can be monitored per slot may not exceed ^{M μ.} M ^μ may be defined as the maximum number of PDCCH candidates per slot in a cell set to a subcarrier interval of 15·2 ^{μ kHz, and may be defined as shown in [Table 19] below.}

	Maximum number of PDCCH candidates per slot and per serving cell ( )
0	44
One	36
2	22
3	20

[Condition 2: Limit the maximum number of CCEs]

The number of CCEs constituting the entire search space per slot (here, the total search space may mean the entire set of CCEs corresponding to the union region of a plurality of search space sets) may not exceed ^{C μ.} C ^μ may be defined as the maximum number of CCEs per slot in a cell set to a subcarrier spacing of 15·2 ^{μ kHz, and may be defined as shown in [Table 20] below.}

	Maximum number of CCEs per slot and per serving cell ( )
0	56
One	56
2	48
3	32

For convenience of description, a situation in which both conditions 1 and 2 are satisfied at a specific time point may be exemplarily defined as “condition A”. Accordingly, not satisfying condition A may mean not satisfying at least one of conditions 1 and 2 described above.

According to the setting of the search space sets of the base station, the condition A may not be satisfied at a specific time point. If condition A is not satisfied at a specific time point, the UE may select and monitor only some of the search space sets configured to satisfy condition A at the corresponding time point, and the base station may transmit the PDCCH to the selected search space set.

According to an embodiment of the present disclosure, the following method may be used as a method of selecting a partial search space from among all set search space sets.

[Method 1]

If condition A for PDCCH is not satisfied at a specific time point (slot),

The terminal (or the base station) may preferentially select a search space set in which a search space type is set as a common search space from among search space sets existing at a corresponding time, over a search space set set as a terminal-specific search space.

When all search space sets set as the common search space are selected (that is, condition A is satisfied even after selecting all search spaces set as the common search space), the terminal (or the base station) uses the terminal-specific search space You can select search space sets set to . In this case, when there are a plurality of search space sets set as the terminal-specific search space, a search space set having a low search space set index may have a higher priority. Considering the priority, the terminal or the base station may select terminal-specific search space sets within a range in which condition A is satisfied.

Hereinafter, methods for allocating time and frequency resources for data transmission in a wireless communication system (5G system or NR system) to which the present disclosure can be applied will be described.

In a wireless communication system (5G system or NR system) to which the present disclosure can be applied, in addition to frequency axis resource candidate allocation through BWP indication, the following detailed frequency domain resource allocation method (frequency domain resource allocation, FD-RA) ) can be provided.

6 is a diagram illustrating an example of allocation of a frequency axis resource of a physical downlink shared channel (PDSCH) in a wireless communication system according to an embodiment of the present disclosure.

Specifically, FIG. 6 shows three frequency axis resource allocation: type 0 (6-00), type 1 (6-05), and dynamic switch (6-10) configurable through a higher layer in the NR system. It is a drawing showing the methods.

Referring to FIG. 6, if the UE is configured to use only resource type 0 through higher layer signaling (6-00), some downlink control information (DCI) for allocating PDSCH to the UE is NRBG It has a bitmap composed of bits. Conditions for this will be described again later. At this time, NRBG means the number of RBGs (resource block groups) determined as shown in [Table 21] below according to the BWP size allocated by the BWP indicator and the upper layer parameter rbg-Size, according to the bitmap. Data is transmitted to the RBG indicated by 1.

Bandwidth Part Size		Configuration 1	Configuration 2
1-36	2	4
37-72	4	8
73-144	8	16
145-275	16	16

If the UE is configured to use only resource type 1 through higher layer signaling (6-05), some DCI for allocating PDSCH to the UE is

It has frequency axis resource allocation information composed of bits. Conditions for this will be described again later. Through this, the base station can set the starting VRB (6-20) and the length (6-25) of frequency-axis resources continuously allocated therefrom.

If the UE is configured to use both resource type 0 and resource type 1 through higher layer signaling (6-10), some DCI for allocating PDSCH to the UE payload (6-15) for setting resource type 0 It has frequency axis resource allocation information consisting of bits of a larger value (6-35) among payloads (6-20, 6-25) for setting resource type 1 and. Conditions for this will be described again later. At this time, one bit may be added to the first part (MSB) of the frequency axis resource allocation information in DCI, and when the bit is 0, it indicates that resource type 0 is used, and when it is 1, it indicates that resource type 1 is used. can be

Hereinafter, a method of allocating time domain resources for a data channel in a next-generation mobile communication system (5G or NR system) will be described.

The base station provides 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) to the terminal, and higher layer signaling (e.g. For example, RRC signaling) can be set. For PDSCH, a table consisting of maxNrofDL-Allocations=16 entries may be configured, and for PUSCH, a table configured with maxNrofUL-Allocations=16 entries may be configured. In an embodiment, the time domain resource allocation information includes the PDCCH-to-PDSCH slot timing (corresponding to the time interval in slot units between the time when the PDCCH is received and the time when the PDSCH scheduled by the received PDCCH is transmitted, denoted by K0. ), PDCCH-to-PUSCH slot timing (corresponding to the time interval in slot units between the time when the PDCCH is received and the time when the PUSCH scheduled by the received PDCCH is transmitted, denoted by K2), the PDSCH or PUSCH within the slot Information on the position and length of the scheduled start symbol, a mapping type of PDSCH or PUSCH, etc. may be included. For example, information such as [Table 22] or [Table 23] below may be notified from the base station to the terminal.

The base station may notify one of the entries in the table for the above-described time domain resource allocation information to the terminal through L1 signaling (eg, DCI) (eg, to be indicated by the 'time domain resource allocation' field in DCI) can). The UE may acquire time domain resource allocation information for the PDSCH or PUSCH based on the DCI received from the base station.

7 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.

Referring to FIG. 7 , the base station has a subcarrier spacing (SCS) of a data channel and a control channel configured by using a higher layer (

,

), a scheduling offset (K ₀ ) value, and an OFDM symbol start position (7-00) and length (7-05) in one slot dynamically indicated through DCI, the time axis position of the PDSCH resource can direct

8 is a diagram illustrating an example of time-base resource allocation according to subcarrier intervals of a data channel and a control channel in a wireless communication system according to an embodiment of the present disclosure.

Referring to FIG. 8, when the subcarrier spacing of the data channel and the control channel are the same (8-00,

=

), since the slot number for data and control are the same, the base station and the terminal can know that a scheduling offset occurs in accordance with _{a predetermined slot offset K 0 .} On the other hand, when the subcarrier spacing of the data channel and the control channel are different (8-05,

), since the slot numbers for data and control are different, the base station and the terminal based on the subcarrier interval of the PDCCH, a scheduling offset according to _{a predetermined slot offset K 0 .} can be seen to occur.

Next, a beam setting method for the base station to transmit control information and data to the terminal will be described. In the present disclosure, for convenience of description, the process of transmitting control information through the PDCCH may be expressed as transmitting the PDCCH, and the process of transmitting data through the PDSCH may be expressed as transmitting the PDSCH.

First, a beam configuration method for the PDCCH will be described.

9 shows a procedure for beam configuration and activation of a PDCCH. First, the list of TCI states for each CORESET may be indicated through the upper layer list such as RRC (9-00). The list of TCI states may be indicated by tci-StatesPDCCH-ToAddList and/or tci-StatesPDCCH-ToReleaseList of [Table 8]. Next, one of the list of the TCI states set for each CORESET may be activated through MAC-CE (9-20). (9-50) shows an example of a MAC-CE structure for TCI state activation of the PDCCH. do. The meaning of each field in the MAC CE and possible values for each field are as follows.

Next, a beam configuration method for the PDSCH will be described.

10 shows a procedure for beam configuration and activation of a PDSCH. The list of TCI state for PDSCH may be indicated through a higher layer list such as RRC (10-00). The list of TCI states may be indicated by, for example, tci-StatesToAddModList and/or tci-StatesToReleaseList in PDSCH-Config IE for each BWP. Next, a part of the list of the TCI state may be activated through the MAC-CE (10-20). The maximum number of activated TCI states may be determined according to the capability reported by the UE. (10-50) shows an example of a MAC-CE structure for TCI state activation/deactivation of a Rel-15 based PDSCH.

The meaning of each field in the MAC CE and possible values for each field are as follows.

When the UE receives DCI format 1_1 or DCI format 1_2, the UE may receive the PDSCH through one beam among the TCI states activated with the MAC-CE based on information of a transmission configuration indication (TCI) field in DCI (10). -40). Whether the TCI field exists is determined by a tci-PresentinDCI value, which is a higher layer parameter in CORESET configured for DCI reception. If tci-PresentinDCI is set to 'enabled' in the upper layer, the UE checks the TCI field of 3 bits information to determine the TCI states activated in the DL BWP or the scheduled component carrier and the direction of the beam linked to the DL-RS can do.

On the other hand, in a wireless communication system (LTE, 5G and NR systems) to which the present disclosure can be applied, the terminal has a procedure of reporting the capability supported by the terminal to the corresponding base station in a state in which it is connected to the serving base station. In the description below, this is referred to as UE capability (reporting). The base station may transmit a UE capability enquiry message for requesting capability report to the terminal in the connected state. In the message, the base station may include a UE capability request for each RAT type. The request for each RAT type may include requested frequency band information. In addition, the UE capability enquiry message may request a plurality of RAT types in one RRC message container, or may include a UE capability enquiry message including a request for each RAT type a plurality of times and deliver it to the UE. That is, the UE capability enquiry is repeated a plurality of times, and the UE may configure a corresponding UE capability information message and report it a plurality of times. In the next-generation mobile communication system, a terminal capability request for MR-DC including NR, LTE, and EN-DC may be made. For reference, the UE capability enquiry message is generally sent initially after the UE establishes a connection, but it can be requested by the base station under any conditions when necessary.

In the above step, the terminal receiving the UE capability report request from the base station configures the terminal capability according to the RAT type and band information requested from the base station. Below, a method for configuring UE capability in the NR system is summarized.

1. If the UE receives a list of LTE and/or NR bands as a UE capability request from the base station, the UE configures a band combination (BC) for EN-DC and NR stand alone (SA). That is, a candidate list of BC for EN-DC and NR SA is constructed based on the bands requested by the base station with FreqBandList. In addition, the priorities of the bands have priorities in the order described in the FreqBandList.

2. If the base station requests a UE capability report by setting the “eutra-nr-only” flag or “eutra” flag, the UE completely removes NR SA BCs from the configured BC candidate list. This operation may occur only when an LTE base station (eNB) requests “eutra” capability.

3. Thereafter, the terminal removes fallback BCs from the candidate list of BCs configured in the above step. Here, fallback BC corresponds to a case in which a band corresponding to at least one SCell is removed from a certain super set BC, and since the super set BC can already cover the fallback BC, it can be omitted. This step also applies to MR-DC, ie LTE bands are also applied. The BCs remaining after this step are the final “candidate BC list”.

4. The UE selects BCs that match the requested RAT type from the final “candidate BC list” and selects BCs to report. In this step, the UE configures the supportedBandCombinationList in the predetermined order. That is, the UE configures the BC and UE capability to be reported according to the preset rat-Type order (nr -> eutra-nr -> eutra). Also, configure featureSetCombination for the configured supportedBandCombinationList, and compose a list of “candidate feature set combination” from the candidate BC list from which the list for fallback BC (including capability of the same or lower level) has been removed. The above “candidate feature set combination” includes both feature set combinations for NR and EUTRA-NR BC, and can be obtained from the feature set combination of UE-NR-Capabilities and UE-MRDC-Capabilities containers.

5. Also, if the requested rat Type is eutra-nr and affects, featureSetCombinations is included in both containers of UE-MRDC-Capabilities and UE-NR-Capabilities. However, the feature set of NR includes only UE-NR-Capabilities.

After the terminal capability is configured, the terminal transmits the UE capability information message including the UE capability to the base station. The base station then performs scheduling and transmission/reception management appropriate for the corresponding terminal based on the UE capability received from the terminal.

11 is a diagram illustrating a radio protocol structure of a base station and a terminal in a single cell, carrier aggregation, and dual connectivity situation according to an embodiment of the present disclosure.

Referring to FIG. 11 , the radio protocol of the next-generation mobile communication system is NR SDAP (Service Data Adaptation Protocol S25, S70), NR PDCP (Packet Data Convergence Protocol S30, S65), NR RLC (Radio Link Control) in the terminal and the NR base station, respectively. S35, S60) and NR MAC (Medium Access Control S40, S55).

A main function of the NR SDAP (S25, S70) may include some of the following functions.

- Transfer of user plane data

- Mapping between a QoS flow and a DRB for both DL and UL for uplink and downlink

- Marking QoS flow ID in both DL and UL packets for uplink and downlink

- A function of mapping a relective QoS flow to a data bearer for uplink SDAP PDUs (reflective QoS flow to DRB mapping for the UL SDAP PDUs).

With respect to the SDAP layer device, the UE can receive a configuration of whether to use the header of the SDAP layer device or the function of the SDAP layer device for each PDCP layer device, for each bearer, or for each logical channel with an RRC message, and the SDAP header If is set, the UE uses the uplink and downlink QoS flow and data bearer mapping information with the NAS QoS reflection setting 1-bit indicator (NAS reflective QoS) and the AS QoS reflection setting 1-bit indicator (AS reflective QoS) of the SDAP header. can be instructed to update or reset . The SDAP header may include QoS flow ID information indicating QoS. The QoS information may be used as data processing priority and scheduling information to support a smooth service.

The main function of the NR PDCP (S30, S65) may include some of the following functions.

- Header compression and decompression (ROHC only)

- Transfer of user data

- In-sequence delivery of upper layer PDUs

- Out-of-sequence delivery of upper layer PDUs

- Order reordering function (PDCP PDU reordering for reception)

- Duplicate detection of lower layer SDUs

- Retransmission of PDCP SDUs

- Encryption and decryption function (Ciphering and deciphering)

- Timer-based SDU discard in uplink.

In the above, the reordering function of the NR PDCP device refers to a function of reordering PDCP PDUs received from a lower layer in order based on a PDCP sequence number (SN), and a function of delivering data to a higher layer in the reordered order. may include, or may include a function of directly delivering without considering the order, may include a function of reordering the order to record the lost PDCP PDUs, and report the status of the lost PDCP PDUs It may include a function for the transmitting side, and may include a function for requesting retransmission for lost PDCP PDUs.

The main function of the NR RLC (S35, S60) may include some of the following functions.

- Data transfer function (Transfer of upper layer PDUs)

- In-sequence delivery of upper layer PDUs

- Out-of-sequence delivery of upper layer PDUs

- ARQ function (Error Correction through ARQ)

- Concatenation, segmentation and reassembly of RLC SDUs

- Re-segmentation of RLC data PDUs

- Reordering of RLC data PDUs

- Duplicate detection

- Protocol error detection

- RLC SDU discard function (RLC SDU discard)

- RLC re-establishment function (RLC re-establishment)

In the above description, the in-sequence delivery function of the NR RLC device refers to a function of sequentially delivering RLC SDUs received from a lower layer to an upper layer, and an original RLC SDU is divided into several RLC SDUs and received. , it may include a function of reassembling it and delivering it, and may include a function of rearranging the received RLC PDUs based on an RLC sequence number (SN) or PDCP SN (sequence number), and rearranging the order It may include a function of recording the lost RLC PDUs, a function of reporting a status on the lost RLC PDUs to the transmitting side, and a function of requesting retransmission of the lost RLC PDUs. and, if there is a lost RLC SDU, it may include a function of sequentially delivering only RLC SDUs before the lost RLC SDU to the upper layer, or if a predetermined timer expires even if there is a lost RLC SDU It may include a function of sequentially delivering all RLC SDUs received before the start of RLC to the upper layer, or if a predetermined timer expires even if there are lost RLC SDUs, all RLC SDUs received so far are sequentially transferred to the upper layer. It may include a function to transmit. In addition, the RLC PDUs may be processed in the order in which they are received (in the order of arrival, regardless of the sequence number and sequence number) and delivered to the PDCP device out of sequence (out-of sequence delivery). Segments stored in the buffer or to be received later are received, reconstructed into one complete RLC PDU, processed and delivered to the PDCP device. The NR RLC layer may not include a concatenation function, and the function may be performed in the NR MAC layer or replaced with a multiplexing function of the NR MAC layer.

In the above, the out-of-sequence delivery function of the NR RLC device refers to a function of directly delivering RLC SDUs received from a lower layer to a higher layer regardless of order, and one RLC SDU originally has several RLCs. When received after being divided into SDUs, it may include a function of reassembling and delivering it, and may include a function of storing the RLC SN or PDCP SN of the received RLC PDUs, arranging the order, and recording the lost RLC PDUs. can

The NR MAC (S40, S55) may be connected to several NR RLC layer devices configured in one terminal, and the main function of the NR MAC may include some of the following functions.

- Mapping function (Mapping between logical channels and transport channels)

- Multiplexing/demultiplexing of MAC SDUs

- Scheduling information reporting function

- HARQ function (Error correction through HARQ)

- Priority handling between logical channels of one UE

- Priority handling between UEs by means of dynamic scheduling

- MBMS service identification

- Transport format selection

- Padding function

The NR PHY layer (S45, S50) channel-codes and modulates the upper layer data, makes an OFDM symbol and transmits it to the radio channel, or demodulates the OFDM symbol received through the radio channel, decodes the channel, and transmits the operation to the upper layer. can be done

The detailed structure of the radio protocol structure may be variously changed according to a carrier (or cell) operating method. For example, when the base station transmits data to the 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, such as S00. On the other hand, when the base station transmits data to the terminal based on CA (carrier aggregation) using multiple carriers in a single TRP, the base station and the terminal have a single structure up to RLC like S10, but a protocol for multiplexing the PHY layer through the MAC layer structure will be used. As another example, when the base station transmits data to the terminal based on DC (dual connectivity) using multiple carriers in multiple TRP, the base station and the terminal have a single structure up to RLC like S20, but the PHY layer through the MAC layer A protocol structure for multiplexing is used.

On the other hand, if the beam configuration or activation of the PDCCH is not performed, the PDCCH reception performance may be deteriorated and the UE may not properly receive downlink control information. To prevent this, in some cases in which PDCCH beam configuration or activation is not performed, a default beam configuration for PDCCH reception may be considered. After the initial access, the UE did not receive one or more TCI state settings through higher layer signaling for CORESET except CORESET 0, or received one or more TCI state settings through higher layer signaling, but MAC-CE for a specific TCI state If activation is not performed through , a basic beam for PDCCH reception may be configured. In this case, the DM-RS used for PDCCH reception may consider a basic beam for PDCCH reception in a manner that assumes that the terminal is in a QCL relationship with the SSB selected at the time of initial access. In addition, after the synchronization reset (Reconfiguration with sync) process, the UE did not receive one or more TCI state settings through higher layer signaling for CORESET except CORESET 0, or received one or more TCI state settings through higher layer signaling. When activation through MAC-CE is not performed for a specific TCI state, a basic beam for PDCCH reception may be configured. In this case, the DM-RS used for PDCCH reception may consider a basic beam of PDCCH reception by assuming that it has a QCL relationship with the SSB selected in the random access process performed during synchronization reconfiguration. If the UE is not instructed to activate the TCI state through MAC-CE after the most recently performed random access procedure except for contention-free random access triggered by the PDCCH order, the UE is Basic beam configuration for PDCCH reception in CORESET 0 may be performed. At this time, for the basic beam configuration for the PDCCH, the DM-RS used for PDCCH reception is the SSB and QCL selected from the most recently performed random access procedures except for the contention-free random access procedure triggered by the PDCCH order by the UE. A basic beam of PDCCH reception may be considered as a method of assuming a relationship.

In this way, when the terminal needs to set the basic beam for CORESET, a problem may occur when the terminal receives downlink data through a plurality of TRPs. When the UE receives downlink data through a plurality of TRPs, the UE may receive up to 5 CORESETs set, and CORESETPoolIndex, which is upper layer signaling, is set for each CORESET, and CORESETs having the same CORESETPoolIndex value are connected to the same TRP It can be assumed that For example, CORESET#1, CORESET#2, and CORESET#3 have 0 as the CORESETPoolIndex value and are connected to TRP#0 and transmitted from TRP#0. It can be connected to #1 and transmitted from TRP#1. In this case, when the UE needs to set the basic beam for CORESET#1 to CORESET#5, it may assume a QCL relationship with the SSB for CORESET#1 to CORESET#5 reception. However, for the reception of CORESET#1, CORESET#2, and CORESET#3 connected to TRP#0, a QCL relationship with the SSB can be assumed regardless of a single TRP or a plurality of TRPs, but a transmission beam different from TRP#0 is used. For CORESET#4 and CORESET#5 transmitted from TRP#1, which are highly likely to be used, if the default beams set in CORESET#1 to CORESET#3 are identically set using the QCL relationship with the SSB, the CORESET connected to TRP#1 Performance degradation may occur for the reception of the PDCCH transmitted in #4 and CORESET #5.

Therefore, in the present disclosure, when the UE receives downlink data through a plurality of TRPs and the basic beam configuration of the PDCCH is required, the PDCCH reception performance is guaranteed by providing the PDCCH basic beam configuration and indication method transmitted in the CORESET from each TRP. Thus, a method for minimizing the transmission delay time of downlink control information and achieving high reliability is proposed. A detailed PDCCH basic beam configuration method will be described with reference to the following embodiments.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In addition, in the description of the present disclosure, if it is determined that a detailed description of a related function or configuration may unnecessarily obscure the subject matter of the present disclosure, the detailed description thereof will be omitted. In addition, the terms described below are terms defined in consideration of functions in the present disclosure, which may vary according to intentions or customs of users and operators. Therefore, the definition should be made based on the content throughout this specification.

For convenience in the following description of the present disclosure, a cell, transmission point, panel, beam or / and a transmission direction and the like are unified and described as a transmission reception point (TRP). Therefore, in actual application, it is possible to appropriately replace TRP with one of the above terms.

Hereinafter, the base station is a subject that performs resource allocation of the terminal, and may be at least one of gNode B, gNB, eNode B, Node B, a base station (BS), a radio access unit, a base station controller, or a node on a network. The terminal may include a user equipment (UE), a mobile station (MS), a cellular phone, a smart phone, a computer, or a multimedia system capable of performing a communication function. In addition, although an embodiment of the present disclosure is described below using an NR or LTE/LTE-A system as an example, the embodiment of the present disclosure may be applied to other communication systems having a similar technical background or channel type. In addition, the embodiments of the present disclosure may be applied to other communication systems through some modifications within a range that does not significantly depart from the scope of the present disclosure as judged by a person having skilled technical knowledge.

The contents of the present disclosure are applicable to FDD and TDD systems.

Hereinafter, in the present disclosure, higher signaling (or higher layer signaling) is a signal transmission method in which a base station uses a downlink data channel of a physical layer to a terminal, or from a terminal to a base station using an uplink data channel of a physical layer, It may also be referred to as RRC signaling, PDCP signaling, or MAC (medium access control) control element (MAC control element; MAC CE).

Hereinafter, in the present disclosure, when the UE determines whether cooperative communication is applied, the PDCCH(s) for allocating the PDSCH to which the cooperative communication is applied has a specific format, or the PDCCH(s) for allocating the PDSCH to which the cooperative communication is applied. PDCCH(s) including a specific indicator indicating whether communication is applied or not, or PDCCH(s) for allocating a PDSCH to which cooperative communication is applied is scrambled with a specific RNTI, or assuming cooperative communication application in a specific section indicated by a higher layer, etc. It is possible to use various methods. Hereinafter, for convenience of description, a case in which a UE receives a PDSCH to which cooperative communication is applied based on conditions similar to the above will be referred to as an NC-JT case.

Hereinafter, in the present disclosure, determining the priority between A and B means selecting one having a higher priority according to a predetermined priority rule and performing an operation corresponding thereto or having a lower priority. It may be mentioned in various ways, such as omit or drop.

Hereinafter, in the present disclosure, the above examples will be described through a plurality of embodiments, but these are not independent and it is possible that one or more embodiments may be applied simultaneously or in combination.

<First embodiment: DCI reception for NC-JT>

A wireless communication system (5G or NR system) to which the present disclosure can be applied can support not only a service requiring a high transmission rate, but also a service having a very short transmission delay and a service requiring a high connection density. A plurality of cells, TRP (transmission and reception point), or coordinated transmission between each cell, TRP or / and beam in a wireless communication network including a beam increases the strength of a signal received by the terminal or each cell, It is one of the element technologies that can satisfy various service requirements by efficiently performing TRP and/or inter-beam interference control.

Joint transmission (JT) is a representative transmission technology for the above-mentioned cooperative communication. Through the joint transmission technology, one terminal is supported through different cells, TRPs, or/and beams to increase the strength of the signal received by the terminal. can On the other hand, since the characteristics of each cell, TRP or / and the channel between the beam and the terminal may be significantly different, it is necessary to apply different precoding, MCS, resource allocation, etc. to each cell, TRP or / and the link between the beam and the terminal. . In particular, for Non-Coherent Joint Transmission (NC-JT) that supports non-coherent precoding between each cell, TRP or/and beam, each cell, TRP or/and Individual downlink (DL) transmission information configuration for beams becomes important. Meanwhile, such individual DL transmission information configuration for each cell, TRP, and/or beam becomes a major factor in increasing the payload required for DL DCI transmission, which is a physical downlink control channel (PDCCH) for transmitting DCI. performance may be adversely affected. Therefore, it is necessary to carefully design a tradeoff between the amount of DCI information and the PDCCH reception performance for JT support.

12 is a diagram illustrating an example of an antenna port configuration and resource allocation for cooperative communication according to some embodiments in a wireless communication system according to an embodiment of the present disclosure.

Referring to FIG. 12 , examples of radio resource allocation for each TRP according to a joint transmission (JT) technique and situation are shown. In FIG. 12, N000 is an example of coherent joint transmission (C-JT) supporting coherent precoding between each cell, TRP, and/or beam. In C-JT, single data (PDSCH) is transmitted from TRP A (N005) and TRP B (N010) to the terminal (N015), and joint precoding is performed in multiple TRPs. This means that TRP A (N005) and TRP B (N010) transmit the same DMRS ports (eg, DMRS ports A and B in both TRPs) for the same PDSCH transmission. In this case, the UE may receive one DCI information for receiving one PDSCH demodulated based on DMRS transmitted through DMRS ports A and B.

In FIG. 12, N020 is an example of non-coherent joint transmission (NC-JT) supporting non-coherent precoding between each cell, TRP or/and beam. In the case of NC-JT, a PDSCH is transmitted to the UE N035 for each cell, TRP, and/or beam, and individual precoding may be applied to each PDSCH. Each cell, TRP or/and beam transmits a different PDSCH to improve throughput compared to single cell, TRP or/and beam transmission, or each cell, TRP or/and beam repeatedly transmits the same PDSCH to transmit a single cell, TRP Alternatively, reliability may be improved compared to beam transmission.

When the frequency and time resources used by a plurality of TRPs for PDSCH transmission are all the same (N040), when the frequency and time resources used by the plurality of TRPs do not overlap at all (N045), the frequency and time used by the plurality of TRPs Various radio resource allocation may be considered, such as when some of the resources overlap (N050). When multiple TRPs repeatedly transmit the same PDSCH to improve reliability in each case of the above-described radio resource allocation, if the receiving terminal does not know whether the corresponding PDSCH is repeatedly transmitted, the corresponding terminal performs combining in the physical layer for the corresponding PDSCH. (combining) cannot be performed, so there may be a limit to improving reliability. Therefore, the present disclosure provides a repeated transmission instruction and configuration method for improving NC-JT transmission reliability.

In order to simultaneously allocate a plurality of PDSCHs to one UE for NC-JT support, DCIs of various types, structures, and relationships may be considered.

13 is a diagram illustrating an example configuration of downlink control information (DCI) for cooperative communication in a wireless communication system according to an embodiment of the present disclosure.

Referring to FIG. 13 , four examples of DCI design for NC-JT support are shown.

Referring to FIG. 13, case #1 (N100) is each other in (N-1) additional TRPs (TRP#1 to TRP#(N-1)) in addition to the serving TRP (TRP#0) used for single PDSCH transmission. In a situation where other (N-1) PDSCHs are transmitted, control information for PDSCH transmitted in (N-1) additional TRPs is in the same format as control information for PDSCH transmitted in serving TRP (same DCI format) This is an example of transmission. That is, the UE uses different TRPs (TRP#0 ~ TRP#(N-1)) through DCIs having the same DCI format and the same payload (DCI#0 ~ DCI#(N-1)) It is possible to obtain control information for PDSCHs transmitted in .

In case #1 described above, each PDSCH control (allocation) degree of freedom may be completely guaranteed, but when each DCI is transmitted in different TRPs, a coverage difference for each DCI may occur and reception performance may be deteriorated.

Case #2 (N105) is different (N-1) in (N-1) additional TRPs (TRP#1 to TRP#(N-1)) in addition to the serving TRP (TRP#0) used for single PDSCH transmission. In a situation where PDSCHs are transmitted, control information for PDSCH transmitted in (N-1) additional TRPs is transmitted in a different format (different DCI format or different DCI payload) from control information for PDSCH transmitted in the serving TRP. This is an example.

For example, DCI#0, which is control information for PDSCH transmitted in the serving TRP (TRP#0), includes all information elements of DCI format 1_0 or DCI format 1_1, but cooperative TRP (TRP#1). In the case of shortened DCI (hereinafter sDCI) (sDCI#0~sDCI#(N-2)), which is control information for PDSCHs transmitted in ~TRP#(N-1)), DCI format 1_0 or DCI format 1_1 information It can contain only some of the elements. Therefore, in the case of sDCI transmitting control information on PDSCHs transmitted in the cooperative TRP, the payload is small compared to normal DCI (nDCI) transmitting PDSCH-related control information transmitted in the serving TRP, or is insufficient compared to nDCI. It is possible to include reserved bits as many as the number of bits.

In case #2 described above, each PDSCH control (allocation) degree of freedom may be limited according to the contents of information elements included in sDCI. It may be less likely to occur.

Case #3 (N110) is different (N-1) in (N-1) additional TRPs (TRP#1 to TRP#(N-1)) other than the serving TRP (TRP#0) used for single PDSCH transmission. In a situation where PDSCHs are transmitted, control information for PDSCH transmitted in (N-1) additional TRPs is transmitted in a different format (different DCI format or different DCI payload) from control information for PDSCH transmitted in the serving TRP. This is an example.

For example, in the case of DCI#0, which is control information for PDSCH transmitted in the serving TRP (TRP#0), includes all information elements of DCI format 1_0 or DCI format 1_1, and cooperative TRP (TRP#1). In the case of control information for PDSCHs transmitted in ~TRP#(N-1)), it is possible to collect and transmit only some of the information elements of DCI format 1_0 or DCI format 1_1 in one 'secondary' DCI (sDCI). For example, the sDCI may include at least one of HARQ-related information such as frequency domain resource assignment of cooperative TRPs, time domain resource assignment, and MCS. In addition, in the case of information not included in sDCI, such as a bandwidth part (BWP) indicator or carrier indicator, DCI (DCI#0, normal DCI, nDCI) of the serving TRP may be followed.

In case #3, each PDSCH control (allocation) degree of freedom may be limited according to the contents of the information element included in the sDCI, but the reception performance of the sDCI can be adjusted, and compared to case #1 or case #2, the terminal's The complexity of DCI blind decoding may be reduced.

Case #4 (N115) is different (N-1) in (N-1) additional TRPs (TRP#1 to TRP#(N-1)) in addition to the serving TRP (TRP#0) used for single PDSCH transmission. In a situation in which PDSCHs are transmitted, control information for PDSCH transmitted in (N-1) additional TRPs is transmitted in DCI (long DCI, IDCI), such as control information for PDSCH transmitted in serving TRP. That is, the UE may acquire control information for PDSCHs transmitted in different TRPs (TRP#0 to TRP#(N-1)) through a single DCI. In case #4, the complexity of DCI blind decoding of the terminal may not increase, but the PDSCH control (allocation) degree of freedom may be low such as the number of cooperative TRPs is limited according to long DCI payload restrictions.

In the following description and embodiments, sDCI may refer to various auxiliary DCIs, such as shortened DCI, secondary DCI, or normal DCI (DCI format 1_0 to 1_1 described above) including PDSCH control information transmitted in cooperative TRP. If not specified, the description is similarly applicable to the various auxiliary DCIs.

In the following description and embodiments, the aforementioned case #1, case #2, and case #3 in which one or more DCIs (PDCCHs) are used to support NC-JT are divided into multiple PDCCH-based NC-JTs, and NC-JT The above-described case #4 in which a single DCI (PDCCH) is used for JT support can be divided into a single PDCCH-based NC-JT.

In embodiments of the present disclosure, “cooperative TRP” may be replaced with various terms such as “cooperative panel” or “cooperative beam” when applied in practice.

In the embodiments of the present disclosure, "when NC-JT is applied" means "when a terminal receives one or more PDSCHs at the same time in one BWP", "when a terminal receives two or more TCIs (Transmission Configuration) at the same time in one BWP" Indicator) indication based on PDSCH reception", "in case the PDSCH received by the terminal is associated with one or more DMRS port groups", etc., can be interpreted variously according to the situation, but for convenience of explanation, one used as an expression.

In the present disclosure, the radio protocol structure for NC-JT may be used in various ways according to TRP deployment scenarios. As an example, when there is no or small backhaul delay between cooperative TRPs, it is possible to use a structure based on MAC layer multiplexing similar to S10 of FIG. 11 (CA-like method). On the other hand, when the backhaul delay between cooperative TRPs is so large that it cannot be ignored (for example, when time of 2 ms or more is required for information exchange between cooperative TRPs, such as CSI, scheduling, HARQ-ACK, etc.), similarly to S20 of FIG. 11, from the RLC layer It is possible to secure a characteristic strong against delay by using an independent structure for each TRP (DC-like method).

<Embodiment 1-1: Method of setting downlink control channel for NC-JT transmission based on Multi-PDCCH>

In multiple PDCCH-based NC-JT, when transmitting DCI for PDSCH schedule of each TRP, it may have a CORESET or search space divided for each TRP. CORESET or search space for each TRP can be set as at least one of the following cases.

● Upper layer index setting for each CORESET: The CORESET setting information set as the upper layer may include an index value, and the TRP for transmitting the PDCCH from the corresponding CORESET may be distinguished by the set index value for each CORESET. That is, in a set of CORESETs having the same higher layer index value, it may be considered that the same TRP transmits a PDCCH or that a PDCCH scheduling a PDSCH of the same TRP is transmitted. The above-described index for each CORESET may be named as CORESETPoolIndex, and it may be considered that the PDCCH is transmitted from the same TRP for CORESETs in which the same CORESETPoolIndex value is set. In the case of CORESET in which the CORESETPoolIndex value is not set, it may be considered that the default value of CORESETPoolIndex is set, and the above-described default value may be 0.

● Multiple PDCCH-Config Configuration: Multiple PDCCH-Configs in one BWP are configured, and each PDCCH-Config may include a PDCCH configuration for each TRP. That is, a list of CORESETs per TRP and/or a list of search spaces per TRP may be configured in one PDCCH-Config, and one or more CORESETs and one or more search spaces included in one PDCCH-Config are considered to correspond to a specific TRP. can do.

● CORESET beam/beam group configuration: TRP corresponding to the corresponding CORESET can be distinguished through a beam or beam group set for each CORESET. For example, when the same TCI state is configured in a plurality of CORESETs, the CORESETs may be considered to be transmitted through the same TRP, or it may be considered that the PDCCH scheduling the PDSCH of the same TRP is transmitted from the corresponding CORESETs.

● Search space beam/beam group configuration: A beam or beam group is configured for each search space, and TRP for each search space can be distinguished through this. For example, if the same beam/beam group or TCI state is configured in multiple search spaces, it can be considered that the same TRP transmits a PDCCH or that a PDCCH scheduling a PDSCH of the same TRP is transmitted in the corresponding search space. have.

By dividing the CORESET or search space by TRP as described above, it is possible to classify PDSCH and HARQ-ACK information for each TRP, and through this, it is possible to generate an independent HARQ-ACK codebook for each TRP and use an independent PUCCH resource.

<Second embodiment: PDCCH basic beam configuration method considering a plurality of TRPs>

According to an embodiment of the present disclosure, a PDCCH basic beam configuration method in consideration of a plurality of TRPs will be described.

When the UE receives downlink data through a plurality of TRPs and the PDCCH basic beam setting is required, the UE receives the PDCCH within the CORESET in which the CORESETPoolIndex corresponding to TRP#1 is set, each CORESET in which the CORESETPoolIndex corresponding to TRP#1 is set. The TCI state corresponding to the lowest index among the one or more TCI states preset in ? may be set as the default beam when receiving the PDCCH in each CORESET.

In addition, when receiving a PDCCH within the CORESET in which the CORESETPoolIndex corresponding to TRP#1 is set, the terminal TRP the TCI state corresponding to the lowest index among the TCI states preset in the CORESET of the lowest index in which the CORESETPoolIndex corresponding to TRP#1 is set. CORESETPoolIndex corresponding to #1 may be set as the default beam for PDCCH reception in all CORESETs configured. In addition, when the terminal receives a PDCCH within the CORESET in which the CORESETPoolIndex corresponding to TRP#1 is set, the TCI state corresponding to the lowest index among the TCI states preset in all CORESETs in which the CORESETPoolIndex corresponding to TRP#1 is set is set to TRP#1. The corresponding CORESETPoolIndex may be set as the default beam for PDCCH reception in all CORESETs configured.

14 is a diagram illustrating an example of configuring a PDCCH basic beam in consideration of a plurality of TRPs according to an embodiment of the present disclosure. When the UE receives downlink data through a plurality of TRPs and the PDCCH basic beam setting is required (14-00), the UE receives the PDCCH in the CORESET in which the CORESETPoolIndex corresponding to TRP#0 is set (14-05) SSB We can assume a QCL relationship with (14-25). For example, after the initial access, the UE does not receive one or more TCI state settings through higher layer signaling for CORESETs in which CORESETPoolIndex corresponding to TRP#0 is set except for CORESET 0, or one or more TCI state settings through higher layer signaling If the TCI state is set but activation through MAC-CE is not performed for a specific TCI state, a default beam for PDCCH reception in CORESET in which CORESETPoolIndex corresponding to TRP#0 is set may be set. In this case, the DM-RS used for PDCCH reception may consider a basic beam for PDCCH reception in a manner that assumes that the terminal is in a QCL relationship with the SSB selected at the time of initial access. In addition, after the synchronization reset (Reconfiguration with sync) process, the UE does not receive one or more TCI state settings through higher layer signaling for CORESET in which CORESETPoolIndex corresponding to TRP #0 is set except for CORESET 0, or higher layer signaling If one or more TCI state settings have been received through , but activation through MAC-CE is not performed for a specific TCI state, a default beam for PDCCH reception in CORESET in which CORESETPoolIndex corresponding to TRP#0 is set can be set. . In this case, the DM-RS used for PDCCH reception may consider a basic beam of PDCCH reception by assuming that it has a QCL relationship with the SSB selected in the random access process performed during synchronization reconfiguration. In addition, when the terminal receives downlink data through a plurality of TRPs and the PDCCH basic beam setting is required (14-00), the terminal receives the PDCCH within the CORESET in which the CORESETPoolIndex corresponding to TRP#1 is set (14-05) , the TCI state corresponding to the lowest index among one or more TCI states preset in each CORESET in which the CORESETPoolIndex corresponding to TRP#1 is set may be set as the default beam when receiving the PDCCH in each CORESET (14-10). In addition, when receiving a PDCCH within the CORESET in which the CORESETPoolIndex corresponding to TRP#1 is set, the terminal TRP the TCI state corresponding to the lowest index among the TCI states preset in the CORESET of the lowest index in which the CORESETPoolIndex corresponding to TRP#1 is set. CORESETPoolIndex corresponding to #1 may be set as a basic beam for PDCCH reception in all configured CORESETs (14-15). In addition, when the terminal receives a PDCCH within the CORESET in which the CORESETPoolIndex corresponding to TRP#1 is set, the TCI state corresponding to the lowest index among the TCI states preset in all CORESETs in which the CORESETPoolIndex corresponding to TRP#1 is set is set to TRP#1. A corresponding CORESETPoolIndex may be set as a basic beam for PDCCH reception in all configured CORESETs (14-20).

<Third embodiment: PDCCH monitoring method in CORESET when setting a PDCCH basic beam considering a plurality of TRPs>

In an embodiment of the present disclosure, a PDCCH monitoring method in CORESET when configuring a PDCCH basic beam in consideration of a plurality of TRPs will be described. When the UE receives downlink data through a plurality of TRPs and the PDCCH basic beam setting is required, the UE receives the PDCCH within the CORESET in which the CORESETPoolIndex corresponding to TRP#1 is set, each CORESET in which the CORESETPoolIndex corresponding to TRP#1 is set. Before receiving the MAC-CE for activating the TCI state, the UE may not monitor the PDCCH in each CORESET in which the CORESETPoolIndex corresponding to TRP#1 is set. If the terminal receives a PDCCH within the CORESET in which the CORESETPoolIndex corresponding to TRP#1 is set, the terminal receives the MAC-CE that activates the TCI state for each CORESET in which the CORESETPoolIndex corresponding to TRP#1 is set. The PDCCH may be received using the TCI state activated by the CE.

15 is a diagram illustrating a PDCCH monitoring method in CORESET when configuring a PDCCH basic beam considering a plurality of TRPs according to an embodiment of the present disclosure. When the UE receives downlink data through a plurality of TRPs and the PDCCH basic beam setting is required (15-00), the UE receives the PDCCH in the CORESET in which the CORESETPoolIndex corresponding to TRP#0 is set (15-05) SSB A QCL relationship with and can be assumed (15-10). For example, after the initial access, the UE does not receive one or more TCI state settings through higher layer signaling for CORESETs in which CORESETPoolIndex corresponding to TRP#0 is set except for CORESET 0, or one or more TCI state settings through higher layer signaling If the TCI state is set but activation through MAC-CE is not performed for a specific TCI state, a default beam for PDCCH reception in CORESET in which CORESETPoolIndex corresponding to TRP#0 is set may be set. In this case, the DM-RS used for PDCCH reception may consider a basic beam for PDCCH reception in a manner that assumes that the terminal is in a QCL relationship with the SSB selected at the time of initial access. In addition, after the synchronization reset (Reconfiguration with sync) process, the UE does not receive one or more TCI state settings through higher layer signaling for CORESET in which CORESETPoolIndex corresponding to TRP #0 is set except for CORESET 0, or higher layer signaling If one or more TCI state settings have been received through , but activation through MAC-CE is not performed for a specific TCI state, a default beam for PDCCH reception in CORESET in which CORESETPoolIndex corresponding to TRP#0 is set can be set. . In this case, the DM-RS used for PDCCH reception may consider a basic beam of PDCCH reception by assuming that it has a QCL relationship with the SSB selected in the random access process performed during synchronization reconfiguration. In addition, when the UE receives downlink data through a plurality of TRPs and the PDCCH basic beam setting is required (15-00), the UE receives the PDCCH within the CORESET in which the CORESETPoolIndex corresponding to TRP#1 is set (15-05) , before receiving a MAC-CE that activates the TCI state for each CORESET in which the CORESETPoolIndex corresponding to TRP#1 is set (15-15), the terminal monitors the PDCCH in each CORESET in which the CORESETPoolIndex corresponding to TRP#1 is set You may not (15-20). If the UE receives a PDCCH within the CORESET in which the CORESETPoolIndex corresponding to TRP#1 is set, after receiving the MAC-CE that activates the TCI state for each CORESET in which the CORESETPoolIndex corresponding to TRP#1 is set (15-15) , the UE may receive the PDCCH using the TCI state activated by MAC-CE (15-25).

16 is a diagram illustrating a structure of a terminal in a wireless communication system according to an embodiment of the present disclosure.

Referring to FIG. 16 , the terminal may include a terminal receiving unit 16-00, a terminal transmitting unit 16-10, and a terminal processing unit (controlling unit) 16-05.

The terminal receiving unit 16-00 and the terminal transmitting unit 16-10 may be referred to as a transceiver together. According to the communication method of the terminal described above, the terminal receiving unit 16-00, the terminal transmitting unit 16-10, and the terminal processing unit 16-05 of the terminal may operate. However, the components of the terminal are not limited to the above-described examples. For example, the terminal may include more components (eg, memory, etc.) or fewer components than the above-described components. In addition, the terminal receiving unit 16-00, the terminal transmitting unit 16-10, and the terminal processing unit 16-05 may be implemented in the form of a single chip.

The terminal receiving unit 16-00 and the terminal transmitting unit 16-10 (or transceiving unit) may transmit/receive signals to and from the base station. Here, the signal may include control information and data. To this end, the transceiver may include an RF transmitter for up-converting and amplifying a frequency of a transmitted signal, and an RF receiver for low-noise amplifying and down-converting a received signal. However, this is only an embodiment of the transceiver, and components of the transceiver are not limited to the RF transmitter and the RF receiver.

In addition, the transceiver may receive a signal through a wireless channel, output it to the terminal processing unit 16-05, and transmit a signal output from the terminal processing unit 16-05 through a wireless channel.

A memory (not shown) may store programs and data necessary for the operation of the terminal. In addition, the memory may store control information or data included in a signal obtained from the terminal. The memory may be configured as a storage medium or a combination of storage media, such as ROM, RAM, hard disk, CD-ROM, and DVD.

The terminal processing unit 16-05 may control a series of processes so that the terminal can operate according to the above-described embodiment of the present disclosure. The terminal processing unit 16-05 may be implemented as a control unit or one or more processors.

17 is a diagram illustrating a structure of a base station in a wireless communication system according to an embodiment of the present disclosure.

Referring to FIG. 17 , the base station may include a base station receiving unit 17-00, a base station transmitting unit 17-10, and a base station processing unit (controlling unit) 17-05.

The base station receiving unit 17-00 and the base station transmitting unit 17-10 may be referred to as a transceiver together. According to the above-described communication method of the base station, the base station receiving unit 17-00, the base station transmitting unit 17-10, and the base station processing unit 17-05 of the base station may operate. However, the components of the base station are not limited to the above-described example. For example, the base station may include more or fewer components (eg, memory, etc.) than the above-described components. In addition, the base station receiver 17-00, the base station transmitter 17-10, and the base station processor 17-05 may be implemented in the form of a single chip.

The base station receiving unit 17-00 and the base station transmitting unit 17-10 (or transceiver) may transmit/receive signals to/from the terminal. Here, the signal may include control information and data. To this end, the transceiver may include an RF transmitter for up-converting and amplifying a frequency of a transmitted signal, and an RF receiver for low-noise amplifying and down-converting a received signal. However, this is only an embodiment of the transceiver, and components of the transceiver are not limited to the RF transmitter and the RF receiver.

In addition, the transceiver may receive a signal through a wireless channel and output it to the base station processing unit 17-05, and transmit the signal output from the base station processing unit 17-05 through the wireless channel.

A memory (not shown) may store programs and data necessary for the operation of the base station. In addition, the memory may store control information or data included in a signal obtained from the base station. The memory may be configured as a storage medium or a combination of storage media, such as ROM, RAM, hard disk, CD-ROM, and DVD.

The base station processing unit 17-05 may control a series of processes so that the base station can operate according to the above-described embodiment of the present disclosure. The base station processing unit 17-05 may be implemented as a control unit or one or more processors.

On the other hand, in the drawings for explaining the method of the present disclosure, the order of description does not necessarily correspond to the order of execution, and the precedence relationship may be changed or may be executed in parallel.

Alternatively, the drawings for explaining the method of the present disclosure may omit some components and include only some components within a range that does not impair the essence of the present disclosure.

In addition, the method of the present disclosure may be performed in combination with some or all of the contents included in each embodiment within a range that does not impair the essence of the disclosure.

Also, although not disclosed in the present disclosure, a method in which a separate table or information including at least one component included in the table proposed in the present disclosure is used is also possible.

On the other hand, the embodiments of the present disclosure disclosed in the present specification and drawings are merely provided for specific examples to easily explain the technical content of the present disclosure and help the understanding of the present disclosure, and are not intended to limit the scope of the present disclosure. That is, it will be apparent to those of ordinary skill in the art to which the present disclosure pertains that other modified examples can be implemented based on the technical spirit of the present disclosure. In addition, each of the above embodiments may be operated in combination with each other as needed. For example, parts of Embodiments 1 to 3 of the present disclosure may be combined with each other to operate a base station and a terminal.

Claims (15)

1. A method of a terminal in a wireless communication system, comprising:

   Receiving, from a base station, first information about at least one first CORESET having a control resource set (CORESET)-related index of 0 and second information about at least one second CORESET having a CORESET-related index of 1;

   checking whether control information for activating at least one transmission configuration indicator (TCI) state for the at least one second CORESET is received;

   checking a default beam based on the second information when the control information is not received; and

   and receiving downlink control information from the at least one second CORESET based on the default beam.
2. According to claim 1,

   The method further comprising the step of omitting monitoring of a physical downlink control channel (PDCCH) in the at least one second CORESET when the control information is not received.
3. According to claim 1,

   The default beam is identified based on information on the TCI state of the lowest index among at least one TCI state for any one CORESET among the at least one second CORESET.
4. According to claim 1,

   The default beam is identified based on information on the TCI state of the lowest index among at least one TCI state for the CORESET of the lowest index among the at least one second CORESET.
5. According to claim 1,

   The default beam is identified based on information on the TCI state of the lowest index among the at least one TCI state for the at least the second CORESET.
6. A method of a base station in a wireless communication system, comprising:

   transmitting first information on at least one first CORESET having a control resource set (CORESET)-related index of 0 and second information on at least one second CORESET having a CORESET-related index of 1 to the terminal; and

   Transmitting downlink control information to the terminal in the at least one second CORESET,

   When the base station does not transmit control information for activating at least one transmission configuration indicator (TCI) state for the at least one second CORESET, the downlink control information is based on a default beam is received by

   The method of claim 1, wherein the default beam is identified based on the second information.
7. 7. The method of claim 6,

   When the base station does not transmit control information for activating at least one TCI state for the at least one second CORESET, monitoring of a physical downlink control channel (PDCCH) in the at least one second CORESET is omitted. how to do it
8. 7. The method of claim 6,

   The default beam includes information on the TCI state of the lowest index among at least one TCI state for any one CORESET among the at least one second CORESET, and at least for the CORESET of the lowest index among the at least one second CORESET. Information on the TCI state of the lowest index among one TCI state, or the default beam is confirmed based on information on the TCI state of the lowest index among at least one TCI state for the at least second CORESET How to.
9. In a terminal of a wireless communication system,

   transceiver; and

   Control the transceiver to receive, from the base station, first information on at least one first CORESET having a control resource set (CORESET)-related index of 0 and second information on at least one second CORESET having a CORESET-related index of 1 do,

   Checking whether control information for activating at least one transmission configuration indicator (TCI) state for the at least one second CORESET is received;

   If the control information is not received, a default beam is checked based on the second information,

   and a controller for controlling the transceiver to receive downlink control information from the at least one second CORESET based on the default beam.
10. 10. The method of claim 9,

    The control unit is

    When the control information is not received, the terminal, characterized in that the monitoring of the PDCCH (physical downlink control channel) in the at least one second CORESET is omitted.
11. 10. The method of claim 9,

    The default beam is identified based on information on the TCI state of the lowest index among at least one TCI state for any one CORESET among the at least one second CORESET.
12. 10. The method of claim 9,

    The default beam is identified based on information on the TCI state of the lowest index among at least one TCI state for the CORESET of the lowest index among the at least one second CORESET.
13. 10. The method of claim 9,

    The default beam is identified based on information on the TCI state of the lowest index among the at least one TCI state for the at least the second CORESET.
14. In a base station of a wireless communication system,

    transceiver; and

    Control the transceiver to transmit first information on at least one first CORESET having a control resource set (CORESET)-related index of 0 and second information on at least one second CORESET having a CORESET-related index of 1 to the terminal, and ,

    a control unit for controlling the transceiver to transmit downlink control information to the terminal in the at least one second CORESET;

    When the base station does not transmit control information for activating at least one transmission configuration indicator (TCI) state for the at least one second CORESET, the downlink control information is based on a default beam is received by

    The base station, characterized in that the default beam is identified based on the second information.
15. 14. The method of claim 13,

    If the base station does not transmit control information for activating at least one TCI state for the at least one second CORESET, monitoring of a physical downlink control channel (PDCCH) in the at least one second CORESET is omitted,

    The default beam includes information on the TCI state of the lowest index among at least one TCI state for any one CORESET among the at least one second CORESET, and at least for the CORESET of the lowest index among the at least one second CORESET. Information on the TCI state of the lowest index among one TCI state, or the default beam is confirmed based on information on the TCI state of the lowest index among at least one TCI state for the at least second CORESET base station.

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