KR20200114986A - Method and apparatus for transmission and reception of control information in wireless communication system - Google Patents

Abstract

The present disclosure relates to a method and apparatus for transmitting and receiving a control channel in wireless communication. According to an embodiment of the present invention, a method for transmitting a control channel by a base station in wireless communication may comprise the steps of: determining configuration information for setting a control channel; transmitting the configuration information to a terminal based on higher layer signaling; and transmitting the control channel to the terminal based on the configuration information.

Description

Method and apparatus for transmitting and receiving control channels in a wireless communication system {METHOD AND APPARATUS FOR TRANSMISSION AND RECEPTION OF CONTROL INFORMATION IN WIRELESS COMMUNICATION SYSTEM}

The present disclosure relates to a method and apparatus for transmitting and receiving a control channel in a wireless communication system. The present disclosure may include a method of setting a search area for a base station or a terminal to transmit and receive a control channel in a wireless communication system.

Efforts are being made to develop an improved 5G communication system or a pre-5G communication system in order to meet the increasing demand for wireless data traffic after the commercialization of 4G communication systems. For this reason, the 5G communication system or the pre-5G communication system is called a communication system after a 4G network (Beyond 4G Network) or a system after an LTE system (Post LTE). The 5G communication system defined by 3GPP is called the New Radio (NR) system.

In order to achieve a high data rate, the 5G communication system is being considered for implementation in the ultra-high frequency (mmWave) band (eg, such as the 60 Giga (60 GHz) band). In order to mitigate the path loss of radio waves in the ultra-high frequency band and increase the transmission distance of radio waves, in 5G communication systems, beamforming, massive MIMO, and Full Dimensional MIMO (FD-MIMO) ), array antenna, analog beam-forming, and large scale antenna technologies were discussed and applied to NR systems.

In addition, in order to improve the network of the system, in 5G communication system, advanced small cell, advanced small cell, cloud radio access network (cloud RAN), ultra-dense network , Device to Device communication (D2D), wireless backhaul, moving network, cooperative communication, CoMP (Coordinated Multi-Points), and interference cancellation And other technologies are being developed. In addition, in the 5G system, advanced coding modulation (ACM) methods such as Hybrid FSK and QAM Modulation (FQAM) and SWSC (Sliding Window Superposition Coding), advanced access technologies such as Filter Bank Multi Carrier (FBMC), NOMA (non-orthogonal multiple access), and sparse code multiple access (SCMA) have been developed.

Meanwhile, the Internet is evolving from a human-centered connection network in which humans create and consume information, to an Internet of Things (IoT) network that exchanges and processes information between distributed components such as objects. IoE (Internet of Everything) technology, which combines IoT technology with big data processing technology through connection with cloud servers, is also emerging. In order to implement IoT, technology elements such as sensing technology, wired/wireless communication and network infrastructure, service interface technology, and security technology are required, and recently, a sensor network for connection between objects, machine to machine , M2M), and MTC (Machine Type Communication) technologies are being studied. In the IoT environment, intelligent IT (Internet Technology) services that create new value in human life by collecting and analyzing data generated from connected objects can be provided. IoT is the field of smart home, smart building, smart city, smart car or connected car, smart grid, healthcare, smart home appliance, advanced medical service, etc. through the convergence and combination of existing IT (iInformation Technology) technology and various industries. Can be applied to.

Accordingly, various attempts have been made to apply a 5G communication system to an IoT network. For example, 5G communication such as a sensor network, machine to machine (M2M), and machine type communication (MTC) is being implemented by techniques such as beamforming, MIMO, and array antenna. As the big data processing technology described above, a cloud radio access network (cloud RAN) is applied as an example of the convergence of 5G technology and IoT technology.

As described above and with the development of a mobile communication system, various services can be provided, and a method for effectively providing these services is required.

The disclosed embodiment provides an apparatus and method capable of effectively providing a service in a mobile communication system.

A method and apparatus for transmitting and receiving a control channel in a wireless communication system according to an embodiment include: determining setting information for setting a control channel, transmitting the setting information to a terminal based on higher layer signaling, and the setting information It may include the step of transmitting the control channel to the terminal based on.

1 is a diagram illustrating an uplink to downlink time-frequency domain transmission structure of an NR or 5G communication system according to an embodiment.
2 is a diagram for explaining a channel access procedure in an unlicensed band according to an embodiment.
3 is a diagram illustrating a resource region through which a data channel is transmitted in an NR or 5G communication system according to an embodiment.
4 is a diagram for describing a control region setting of a downlink control channel in an NR or 5G communication system according to an embodiment.
5 is a diagram illustrating a structure of a downlink control channel in an NR or 5G communication system according to an embodiment.
6 is a diagram for describing a method of setting a control channel region according to an exemplary embodiment.
7 is a diagram for describing a method of setting a control channel region according to an exemplary embodiment.
8A is a diagram illustrating a method of setting a control channel region according to an embodiment.
8B is a diagram illustrating a method of setting a control channel region according to an embodiment.
9 is a diagram for describing a method of setting a control channel region according to an embodiment.
10 is a flowchart illustrating an operation of a base station according to an embodiment.
11 is a flowchart illustrating an operation of a terminal according to an embodiment.
12 is a block diagram showing the structure of a base station according to an embodiment.
13 is a block diagram showing the structure of a terminal according to an embodiment.

Hereinafter, embodiments of the present disclosure will be described in detail together with the accompanying drawings. In addition, in describing the present disclosure, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present disclosure, the detailed description thereof will be omitted. In addition, terms to be described later are terms defined in consideration of functions in the present disclosure and may vary according to the intention or custom of users or operators. Therefore, the definition should be made based on the contents throughout this specification.

Advantages and features of the present disclosure, and a method of achieving them will be apparent with reference to embodiments described later in detail together with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below, but may be implemented in a variety of different forms, and only these embodiments make the disclosure of the present disclosure complete, and common knowledge in the technical field to which the disclosure belongs. It is provided to completely inform the scope of the invention to those who have it, and the present disclosure is only defined by the scope of the claims. The same reference numerals refer to the same components throughout the specification.

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 belongs and are not directly related to the present disclosure will be omitted. This is to more clearly convey the gist of the present disclosure by omitting unnecessary description.

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

Advantages and features of the present disclosure, and a method of achieving them will be apparent with reference to embodiments described later in detail together with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below, but may be implemented in a variety of different forms, and only these embodiments make the disclosure of the present disclosure complete, and common knowledge in the technical field to which the disclosure belongs. It is provided to completely inform the scope of the invention to those who have it, and the present disclosure is only defined by the scope of the claims. The same reference numerals refer to the same components throughout the specification.

At this time, it will be appreciated that each block of the flowchart diagrams and combinations of the flowchart diagrams may be executed by computer program instructions. Since these computer program instructions can be mounted on the processor of a general purpose computer, special purpose computer or other programmable data processing equipment, the instructions executed by the processor of the computer or other programmable data processing equipment are described in the flowchart block(s). It creates a means to perform functions. These computer program instructions can also be stored in computer-usable or computer-readable memory that can be directed to a computer or other programmable data processing equipment to implement a function in a particular way, so that the computer-usable or computer-readable memory It is also possible to produce an article of manufacture containing instruction means for performing the functions described in the flowchart block(s). Computer program instructions can also be mounted on a computer or other programmable data processing equipment, so that a series of operating steps are performed on a computer or other programmable data processing equipment to create a computer-executable process to create a computer or other programmable data processing equipment. It is also possible for instructions to perform processing equipment to provide steps for executing the functions described in the flowchart block(s).

In addition, each block may represent a module, segment, or part of code that contains one or more executable instructions for executing the specified logical function(s). In addition, it should be noted that in some alternative execution examples, functions mentioned in blocks may occur out of order. For example, two blocks shown in succession may in fact be executed substantially simultaneously, or the blocks may sometimes be executed in reverse order depending on the corresponding function.

In this case, the term'~ unit' used in the present embodiment means software or hardware components such as FPGA or ASIC, and'~ unit' performs certain roles. However,'~ part' is not limited to software or hardware. The'~ unit' may be configured to be in an addressable storage medium, or may be configured to reproduce one or more processors. Thus, as an example,'~ unit' refers to components such as software components, object-oriented software components, class components and task components, processes, functions, properties, and procedures. , Subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, database, data structures, tables, arrays, and variables. The components and functions provided in the'~ units' may be combined into a smaller number of elements and'~ units', or may be further divided into additional elements and'~ units'. In addition, components and'~ units' may be implemented to play one or more CPUs in a device or a security multimedia card. Also, in an embodiment,'~ unit' may include one or more processors.

The 5G system is considering supporting various services compared to the existing 4G system. For example, the most representative services are mobile ultra-wide band communication service (eMBB: enhanced mobile broad band), ultra-reliable and low latency communication service (URLLC: ultra-reliable and low latency communication), and large-scale device-to-device communication service (mMTC: massive machine type communication), evolved multimedia broadcast/multicast service (eMBMS), and the like. In addition, a system providing the above-described URLLC service may be referred to as a URLLC system, and a system providing an eMBB service may be referred to as an eMBB system. In addition, the terms service and system may be used interchangeably.

In this way, a plurality of services may be provided to users in a communication system, and in order to provide such a plurality of services to users, a method for providing each service within the same time period according to the characteristics of each service and The device used may be required.

According to an embodiment of the present disclosure, a system and a node for receiving a downlink signal in a wireless communication system or a system and a node for transmitting a downlink signal set a downlink control channel region in consideration of subbands, thereby controlling downlink Channel reception and monitoring efficiency can be improved.

Meanwhile, in a wireless communication system, for example, an LTE or LTE-A system, or a 5G New Radio (NR) system, a downlink transmitted by a base station to a terminal through a downlink control channel (PDCCH). Downlink Control Information (DCI) including resource allocation information through which a signal is transmitted may be transmitted. For the UE, the base station provides downlink control information (e.g., Channel-State Information Reference Signal (CSI-RS)), or a broadcast channel (Physical Broadcast CHannel (PBCH)), or a downlink data channel (Physical Downlink Shared CHannel (PDSCH)). )) can be configured to receive at least one downlink signal.

For example, in subframe n, the base station may transmit downlink control information (DCI) instructing the UE to receive the PDSCH in subframe n through the PDCCH. A terminal receiving the above-described downlink control information (DCI) may receive the PDSCH in subframe n according to the received downlink control information. In addition, in an LTE or LTE-A or NR system, the base station may transmit downlink control information (DCI) including uplink resource allocation information to the terminal through a downlink control channel (PDCCH). The base station provides uplink control information (e.g., Sounding Reference Signal (SRS), Uplink Control Information (UCI) or Physical Random Access CHannel (PRACH)) or an uplink data channel (Physical Uplink Shared CHannel) through the above-described operation. (PUSCH)) can be configured to transmit at least one uplink signal to the base station. For example, the terminal receiving the uplink transmission configuration information (or uplink DCI or UL grant) transmitted through the PDCCH from the base station in subframe n, a predefined time (eg, n+4), Uplink data channel according to a time set through a higher signal (eg, n+k) or uplink signal transmission time indicator information (eg, n+k) included in the above-described uplink transmission configuration information Transmission (hereinafter, PUSCH transmission) may be performed.

When the configured downlink transmission is transmitted from the base station to the terminal through the unlicensed band, or when the configured uplink transmission is transmitted from the terminal to the base station through the unlicensed band, the above-described transmitting device (base station or terminal) is prior to the set signal transmission start point or Immediately before, it is possible to perform a channel access procedure (or listen-before talk: LBT) for an unlicensed band in which the above-described signal transmission is configured. When it is determined that the unlicensed band is in an idle state according to the result of performing the above-described channel access procedure, the transmitting device may access the unlicensed band and perform the above-described signal transmission.

If it is determined that the unlicensed band is not idle or occupied according to the result of the channel access procedure performed by the transmitting device, the transmitting device cannot access the unlicensed band. It may be impossible to perform transmission of the set signal.

In general, the channel access procedure in the unlicensed band in which signal transmission is configured may be as follows. The transmitting device may receive a signal in the above-described unlicensed band for a predetermined time or a time calculated according to a predefined rule (eg, at least a time calculated through a random value selected by the base station or the terminal). The transmitting device calculates the strength of the received signal by a function consisting of at least one variable among predefined or defined channel bandwidth or the bandwidth of the signal to which the signal to be transmitted is transmitted, the strength of the transmission power, and the beam width of the transmitted signal. It is possible to determine the idle state of the above-described unlicensed band by comparing the threshold value.

For example, when the strength of a signal received for 25us from the transmitting device is less than a predefined threshold value of -72dBm, the transmitting device may determine that the unlicensed band is in an idle state, and may perform a set signal transmission. At this time, the maximum possible time for signal transmission is the maximum channel occupancy time defined for each country or region in the unlicensed band, or the type of transmission device (for example, a base station or a terminal, or a master device or a slave device). May be limited according to For example, in the case of Japan, in the 5GHz unlicensed band, a base station or a terminal can transmit a signal by occupying the above-described channel without performing an additional channel access procedure for a maximum of 4 ms after performing a channel access procedure. If the strength of the signal received for 25us is greater than the predefined threshold -72dBm, the transmitting device, for example, the base station may determine that the above-described unlicensed band is not in an idle state, and may not transmit the signal.

In the case of a 5G communication system, in order to provide various services and support a high data rate, various technologies such as a technology capable of transmitting an uplink signal without retransmission in units of a code block group and uplink scheduling information have been introduced. Therefore, in the case of performing the above-described 5G communication system through an unlicensed band, a more efficient channel access procedure in consideration of various variables may be required.

The wireless communication system deviated from the initial voice-oriented service, for example, 3GPP HSPA (High Speed Packet Access), LTE (Long Term Evolution or E-UTRA (Evolved Universal Terrestrial Radio Access)), LTE-Advanced. (LTE-A), 3GPP2's High Rate Packet Data (HRPD), UMB (Ultra Mobile Broadband), and IEEE's 802.16e, such as communication standards, developed into a broadband wireless communication system that provides high-speed, high-quality packet data services. Are doing. In addition, a communication standard of 5G or NR (new radio) is being created as a 5th generation wireless communication system.

In this way, in a wireless communication system including the 5th generation, at least one service of eMBB (Enhanced mobile broadband), mMTC (massive Machine Type Communications) (mMTC), and URLLC (Ultra-Reliable and low-latency Communications) can be provided to the terminal. have. The above-described services may be provided to the same terminal during the same time period. In an embodiment, eMBB may be a service for high-speed transmission of high-capacity data, mMTC may be a service aiming at minimizing terminal power and accessing multiple terminals, and URLLC for high reliability and low latency, but is not limited thereto. The three services described above may be a major scenario in a system such as an LTE system or a 5G/NR (new radio, next radio) after LTE system.

When the base station schedules data corresponding to the eMBB service to a certain terminal in a specific transmission time interval (TTI), when a situation in which URLLC data must be transmitted in the above-described TTI occurs, the above-described eMBB data is already transmitted. Instead of transmitting part of the eMBB data in a frequency band that is scheduled and transmitted, the above-described URLLC data may be transmitted in the above-described frequency band. The above-described eMBB-scheduled terminal and the URLLC-scheduled terminal may be the same terminal or different terminals. In such a case, the possibility of damage to the eMBB data increases because a portion of the eMBB data that has already been scheduled and transmitted is not transmitted. Accordingly, in the above-described case, it is necessary to determine a method for processing a signal received from a terminal receiving eMBB scheduling or a terminal scheduling URLLC and a signal receiving method.

Hereinafter, embodiments of the present disclosure will be described in detail together with the accompanying drawings. In addition, in describing the present disclosure, when it is determined that a detailed description of a related function or configuration may unnecessarily obscure the subject matter of the present disclosure, a detailed description thereof will be omitted. In addition, terms to be described later are terms defined in consideration of functions in the present disclosure and may vary according to the intention or custom of users or operators. Therefore, the definition should be made based on the contents throughout this specification. Hereinafter, the base station may be at least one of an eNode B, a Node B, a base station (BS), a radio access unit, a base station controller, or a node on a network as a subject performing resource allocation of the terminal. The terminal may include a user equipment (UE), a mobile station (MS), a cellular phone, a smart phone, a computer, or a multimedia system capable of performing a communication function. In the present disclosure, a downlink (DL) may refer to a radio transmission path of a signal transmitted from a base station to a terminal, and an uplink (UL) refers to a radio transmission path of a signal transmitted from the terminal to the base station. can do. In addition, hereinafter, an embodiment of the present disclosure will be described using an LTE or LTE-A system as an example, but an embodiment of the present disclosure may be applied to other communication systems having a similar technical background or channel type. For example, 5G mobile communication technology (5G, new radio, NR) developed after LTE-A may be included. In addition, the embodiments of the present disclosure may be applied to other communication systems through some modifications without significantly departing from the scope of the present disclosure, as determined by a person having skilled technical knowledge.

As a representative example of the above-described broadband wireless communication system, an NR system employs an Orthogonal Frequency Division Multiplexing (OFDM) scheme in a downlink (DL), and an OFDM and Single Carrier (SC-FDMA) scheme in an uplink (UL). Frequency Division Multiple Access) is adopted. Uplink may mean a radio link through which a terminal (terminal or user equipment, UE) or a mobile station ((MS) transmits data or control signals to a base station (eNode B, or base station (BS)), and downlink May mean a radio link through which the base station transmits data or control signals to the terminal.In the multiple access method as described above, in general, time-frequency resources for carrying data or control information for each user do not overlap each other, that is, Each user's data or control information can be classified by assigning and operating so that orthogonality is established.

When a decoding failure occurs in initial transmission, the NR system may employ a hybrid automatic repeat request (HARQ) scheme in which the corresponding data is retransmitted in the physical layer. In the HARQ scheme, when the receiver fails to accurately decode (decode) data, the receiver transmits information (Negative Acknowledgement) notifying the transmitter of the decoding failure to enable the transmitter to retransmit the corresponding data in the physical layer. The receiver may improve data reception performance by combining data retransmitted by the transmitter with data that has previously failed to be decoded. In addition, when the receiver correctly decodes data, information (ACK) notifying the transmitter of decoding success may be transmitted to enable the transmitter to transmit new data.

1 is a diagram illustrating an uplink to downlink time-frequency domain transmission structure of an NR system according to an embodiment. More specifically, FIG. 1 is a diagram for explaining the basic structure of a time-frequency domain, which is a radio resource domain in which the above-described data or control channel is transmitted in an uplink/downlink of an NR system or a similar system.

Referring to FIG. 1, the horizontal axis represents the time domain and the vertical axis represents the frequency domain. The minimum transmission unit in the time domain is an OFDM to DFT-s-OFDM symbol, and Nsymb (101) OFDM to DFT-s-OFDM symbols may be collected to form one slot 102. Here, the OFDM symbol may mean a symbol for transmitting and receiving a signal using an OFDM multiplexing scheme, and the DFT-s-OFDM symbol is for transmitting and receiving a signal using a DFT-s-OFDM or SC-FDMA multiplexing scheme. It may mean a symbol for. In the present disclosure, for convenience of explanation, OFDM and DFT-s-OFDM symbols will be commonly used as OFDM symbols without distinction, and will be described based on downlink signal transmission and reception, but the present disclosure is also applied to uplink signal transmission and reception. What is possible will be fully understood by those skilled in the art.

When the interval between subcarriers is 15 kHz, one slot may be gathered to form one subframe 103, and the lengths of the slots and subframes described above may be 1 ms, respectively. In this case, the number of slots and the length of the slots constituting one subframe 103 may be different according to the interval between subcarriers. For example, when the interval between subcarriers is 30 kHz, four slots may be gathered to form one subframe 103. In this case, the length of the slot may be 0.5 ms and the length of the subframe may be 1 ms.

The radio frame 104 may be a time domain section consisting of 10 subframes. The minimum transmission unit in the frequency domain is a subcarrier, and the bandwidth of the entire system transmission bandwidth may consist of a total of N _BW (105) subcarriers. However, these specific values can be applied variably. For example, in the case of an LTE system, the interval between subcarriers is 15 kHz, but two slots are gathered to form one subframe 103, in which case the length of the slot is 0.5 ms and the length of the subframe is 1 ms.

The basic unit of a resource in the time-frequency domain is a resource element (RE) 106, which can be represented by an OFDM symbol index and a subcarrier index. The resource block 107 (Resource Block; RB or Physical Resource Block; PRB) may be defined as N _symb (101) consecutive OFDM symbols in the time domain and N _SC ^RB (108) consecutive subcarriers in the frequency domain. . Therefore, one RB 107 in one slot is N _symb ×N _SC ^RB may contain REs. In general, the minimum allocation unit in the frequency domain of data may be the RB 107 described above. In the NR system, N _symb = 14 and N _SC ^RB = 12 are generally described above, and the number of _RBs (N _RB ) may vary according to the bandwidth of the system transmission band. In the LTE system, N _symb = 7, N _SC ^RB = 12, as described above, and N _RB may vary according to the bandwidth of the system transmission band.

The downlink control information may be transmitted within the first N OFDM symbols in the above-described subframe. In general, it may be N = {1, 2, 3}, and the terminal may receive the number of symbols to which the above-described downlink control information can be transmitted through an upper signal from the base station. In addition, according to the amount of control information to be transmitted in the current slot, the base station may vary the number of symbols through which downlink control information can be transmitted in the above-described slot for each slot, and separate information on the number of symbols described above. It can be delivered to the terminal through the downlink control channel of.

In the NR to LTE system, scheduling information for downlink data or uplink data may be transmitted from the base station to the terminal through downlink control information (DCI). DCI can be defined according to various formats. For example, DCI according to each format is whether scheduling information (UL grant) for uplink data or scheduling information (DL grant) for downlink data, compact DCI with a small size of control information, control information It may indicate whether it is fall-back DCI, whether spatial multiplexing using multiple antennas is applied, whether DCI is for power control, and the like. For example, the DCI format (for example, DCI format 1_0 of NR), which is scheduling control information (DL grant) for downlink data, may include at least one of the following control information.

-Control information identifier (DCI format identifier): Identifier that separates the received DCI format

-Frequency domain resource assignment: indicates the RB allocated for data transmission.

-Time domain resource assignment: indicates slots and symbols allocated for data transmission.

-VRB-to-PRB mapping: indicates whether to apply the VRB mapping method

-Modulation and coding scheme (MCS): Indicate the modulation method used for data transmission and the size of the transport block, which is the data to be transmitted.

-New data indicator: indicates whether HARQ initial transmission or retransmission.

-Redundancy version: indicates a redundancy version of HARQ.

-HARQ process number: indicates the process number of HARQ.

-PDSCH allocation information (Downlink assignment index): Indicate the number of PDSCH reception results to be reported to the base station to the terminal (eg, the number of HARQ-ACKs)

-Transmit Power Control (TPC) command for PUCCH (Physical Uplink Control CHannel) (PUCCH): Indicates a transmit power control command for PUCCH, which is an uplink control channel.

-PUCCH resource indicator (PUCCH resource indicator): PUCCH resource indication used for HARQ-ACK report including the reception result for the PDSCH configured through the corresponding DCI

-PUCCH transmission timing indicator (PDSCH-to-HARQ_feedback timing indicator): indicates slot or symbol information in which PUCCH should be transmitted for HARQ-ACK reporting including a reception result for the PDSCH configured through the corresponding DCI

The above-described DCI is a downlink physical downlink control channel (PDCCH) (or control information, hereinafter to be used in combination) or EPDCCH (Enhanced PDCCH) (or enhanced control information, which is a downlink physical control channel through channel coding and modulation process). It can be transmitted on the following mixed use).

In general, the above-described DCI is scrambled with a specific Radio Network Temporary Identifier (RNTI) (or terminal identifier C-RNTI (Cell Radio Network Temporary Identifier)) independently for each terminal, and a cyclic redundancy check (CRC) is added, and the channel After being coded, each may be configured as an independent PDCCH and transmitted. In the time domain, the PDCCH may be mapped and transmitted during the above-described control channel transmission period. The frequency domain mapping position of the PDCCH may be determined by an identifier (ID) of each terminal, and may be transmitted over the entire system transmission band.

Downlink data may be transmitted on a physical downlink shared channel (PDSCH), which is a physical channel for transmitting downlink data. The PDSCH may be transmitted after the above-described control channel transmission period, and scheduling information such as a specific mapping position and modulation scheme in the frequency domain may be determined based on the DCI transmitted through the aforementioned PDCCH.

Among the control information constituting the DCI described above, through the MCS, the base station may notify the terminal of the modulation method applied to the PDSCH to be transmitted and the size of the data to be transmitted (transport block size (TBS)). In an embodiment, the MCS may consist of 5 bits or more or less bits. The above-described TBS may correspond to a size before channel coding for error correction is applied to data (transport block, TB) intended to be transmitted by the base station.

Modulation methods supported by the NR system may include Quadrature Phase Shift Keying (QPSK), Quadrature Amplitude Modulation (16QAM), 64QAM, and 256QAM, and each of the modulation orders (Qm) is 2, 4, 6 to be. That is, in the case of QPSK modulation, 2 bits per symbol, in the case of 16QAM modulation, 4 bits per symbol, in the case of 64QAM modulation, 6 bits per symbol, and in the case of 256QAM modulation, 8 bits per symbol can be transmitted. In addition, a modulation scheme of 256QAM or more may be used according to system modifications.

In the NR system, the uplink/downlink HARQ employs an asynchronous HARQ scheme in which data retransmission time is not fixed. In the example of downlink, when a HARQ NACK is fed back from the terminal for initial transmission data transmitted by the base station, the base station can freely determine the transmission time of the retransmission data by the scheduling operation. The UE may perform decoding on received data for the HARQ operation, buffer data determined as an error as a result, and then perform combining with data retransmitted from the base station. HARQ ACK/NACK information of the PDSCH transmitted in subframe n-k may be transmitted from the terminal to the base station through PUCCH or PUSCH in subframe n. In a 5G communication system such as NR, the k value described above may be included in DCI indicating or scheduling reception of the PDSCH transmitted in subframe n-k and transmitted, or may be set to the terminal through an upper signal. In this case, the base station may set one or more k values as higher signals, and may indicate a specific k value through the above-described DCI. In this case, the above-described k may be determined according to the HARQ-ACK processing capability of the terminal, that is, the minimum time required for the terminal to receive the PDSCH and generate and report the HARQ-ACK for the above-described PDSCH. In addition, the terminal may use a predefined value or a default value until the above-described k value is set.

Hereinafter, the description of the wireless communication system and the method and apparatus proposed in the embodiment of the present disclosure have been described based on the NR system, but the contents of the present disclosure are not limited to the NR system, but LTE, LTE-A , LTE-A-Pro, 5G, etc. can be applied in various wireless communication systems. In addition, although the present disclosure has been described based on a system and a device that transmits and receives signals using an unlicensed band, the contents of the present disclosure may be applied to a system operating in a licensed band.

Hereinafter, in the present disclosure, the higher signaling or higher signal may be a signal transmission method transmitted from the base station to the terminal using the downlink data channel of the physical layer, or from the terminal to the base station using the uplink data channel of the physical layer. It may include signaling, or PDCP signaling, or a signal transmission method delivered through a MAC control element (MAC CE). In addition, the above-described higher signaling or higher signal may include system information commonly transmitted to a plurality of terminals, for example, a system information block (SIB).

In a system that performs communication in an unlicensed band, a transmitting device (base station or terminal) that intends to transmit a signal through the unlicensed band has a channel access procedure for the unlicensed band to perform the above-described communication before transmitting the above-described signal ( Channel access procedure, or LBT: listen-before talk) can be performed. When it is determined that the above-described unlicensed band is idle according to the channel access procedure, the transmitting device may access the unlicensed band and perform signal transmission. If it is determined that the above-described unlicensed band is not in an idle state according to the performed channel access procedure, the transmitting device may not be able to perform signal transmission.

In the channel access procedure in the unlicensed band, generally, the transmitting device is a fixed time or a time calculated according to a predefined rule (e.g., a time calculated through at least one random value selected by the base station or the terminal) While it is possible to measure the strength of a signal received through the above-described unlicensed band. The transmitting device is a threshold value that is defined in advance or calculated by a function that determines the magnitude of the received signal strength consisting of at least one variable from among the channel bandwidth, the bandwidth of the signal to which the signal to be transmitted is transmitted, the strength of the transmission power, etc. By comparing with (threshold), it is possible to determine the idle state of the above-described unlicensed band.

For example, the transmitting device measures the strength of the signal during Xus (e.g. 25us) just before the time it is intended to transmit the signal, and the measured signal strength is a predefined or calculated threshold T (e.g. -72dBm). ), it is determined that the above-described unlicensed band is in an idle state, and a set signal may be transmitted. At this time, after the channel access procedure, the maximum time for continuous signal transmission may be limited according to the maximum channel occupancy time defined for each country, region, and frequency band according to each unlicensed band. It may also be limited according to the type of (for example, a base station or a terminal, or a master device or a slave device). For example, in Japan, in a 5GHz unlicensed band, a base station or a terminal transmits a signal by occupying the above-described channel without performing an additional channel access procedure for a maximum of 4 ms for an unlicensed band determined to be idle after performing a channel access procedure. I can.

More specifically, when the base station or the terminal wants to transmit a downlink or uplink signal in an unlicensed band, the above-described channel access procedure that the base station or terminal can perform may be classified into at least the following types and described.

-Type 1: Up/down link signal transmission after performing channel access procedure for variable time

-Type 2: Uplink/downlink signal transmission after performing channel access procedure for a fixed time

-Type 3: Transmission of downlink or uplink signals without performing a channel access procedure

In the present disclosure, a case in which a base station transmits a downlink signal to a terminal through an unlicensed band and a case in which the terminal transmits an uplink signal to a base station through an unlicensed band will be described in combination. However, the content proposed in this disclosure can be applied in the same manner or partially modified when the terminal transmits an uplink signal to the base station through an unlicensed band or when the base station transmits a downlink signal to the terminal through an unlicensed band. . Therefore, detailed description of transmission and reception of downlink signals will be omitted. In addition, in the present disclosure, it is assumed that one downlink data information (codeword or TB) or uplink data information is transmitted and received between a base station and a terminal. However, the content proposed in the present disclosure may be applicable to a case where a base station transmits a downlink signal to a plurality of terminals, or when a plurality of codewords or TBs are transmitted and received between the base station and the terminal.

A transmitting node (hereinafter referred to as a base station or a terminal) that wants to transmit a signal in an unlicensed band may determine a channel access procedure method according to the type of signal to be transmitted. For example, when the base station wants to transmit a downlink signal including a downlink data channel in an unlicensed band, the base station may perform a Type 1 channel access procedure. And when the base station wants to transmit a downlink signal that does not include a downlink data channel in an unlicensed band, for example, when it wants to transmit a synchronization signal or a downlink control channel, the base station performs a type 2 channel access procedure. And transmit the downlink signal described above.

In this case, the base station may determine the channel access procedure method according to the transmission length of the signal to be transmitted in the unlicensed band, the time to occupy and use the above-described unlicensed band or the length of the interval. In general, the Type 1 method may have to perform the channel access procedure for a longer time than the Type 2 method. Accordingly, when the base station wants to transmit a signal for a short time period or a time period less than or equal to a reference time (eg, Xms or Y symbol), the base station may perform a Type 2 channel access procedure. On the other hand, the base station may perform a Type 1 channel access procedure when it wants to transmit a signal during a time period exceeding or exceeding a long time period or a reference time (eg, Xms or Y symbol). In other words, the base station may perform different channel access procedures according to the use time of the unlicensed band.

If, in the case of performing the Type 1 channel access procedure according to at least one of the above-described criteria, the base station is the type of channel access priority according to the quality of service class identifier (QCI) of the signal to be transmitted in the above-described unlicensed band ( channel access priority class), and for the determined channel access priority type, a channel access procedure may be performed by using at least one or more values among predefined setting values as shown in Table 1. For example, QCI 1, 2, and 4 may mean QCI values for services such as Conversational Voice, Conversational Video (Live Streaming), and Non-Conversational Video (Buffered Streaming), respectively. If a signal for a service that does not match the QCI in Table 1 is to be transmitted to the unlicensed band, the base station may select the service described above and the QCI closest to the QCI in Table 1 and select a channel access priority type for this. .

Table 1 is a table showing the mapping relationship between Channel Access Priority Classes and QCI.

For example, with reference to Table 2 to be described later, the base station determines a set of values or sizes (CW_p) and contention windows according to the determined channel access priority (p). It is possible to determine the minimum and maximum values (CW_min,p, CW_max,p), and the maximum channel occupancy period (T_mcot,p). In other words, a base station that wants to transmit a downlink signal in the unlicensed band may perform a channel access procedure for the unlicensed band for a minimum of T_f + m_p*T_sl time.

When performing the channel access procedure with the channel access priority type 3 (p=3), the size of the delay interval required to perform the above-described channel access procedure, T_f + m_p*T_sl, is the size using m_p=3. Can be set. If it is determined that the above-described unlicensed band is idle in all of the above-described m_p*T_sl times, N=N-1 may be obtained. In this case, N may be selected as an arbitrary integer value from a value between 0 and a value of the contention period (CW_p) at the time point in which the above-described channel access procedure is performed. Referring to Table 2, in the case of channel access priority type 3, the minimum contention interval value and the maximum contention interval value are 15 and 63, respectively. When it is determined that the above-described unlicensed band is idle in the above-described delay period and the additional channel access procedure execution period, the base station may transmit a signal through the above-described unlicensed band for a time T_mcot,p (8 ms).

Table 2 is a table showing a channel access priority class in the downlink. In the present disclosure, for convenience of description, a downlink channel access priority class will be used. However, in the case of uplink, the channel access priority class of Table 2 may be reused, or a channel access priority class for uplink transmission may be defined and used.

The initial contention section value (CW_p) may be the minimum value (CW_min,p) of the contention section. The base station selecting the above-described N value may perform a channel access procedure in the T_sl interval. When the base station determines that the unlicensed band is idle through the channel access procedure performed in the above-described T_sl section, the base station changes the value to N=N-1, and when N=0, transmits the signal through the unlicensed band at maximum T_mcot, The signal can be transmitted for p time. If the unlicensed band determined through the channel access procedure at the time T_sl described above is not in an idle state, the base station may perform the channel access procedure again without changing the N value.

The value of the contention period (CW_p) described above is a time point at which the base station initiates a channel access procedure, a time point at which the base station selects the aforementioned N value to perform the channel access procedure, or immediately before, the base station selects the aforementioned unlicensed band. It may be changed based on a reception result for a downlink data channel in a reference subframe or a reference slot among the most recently transmitted downlink signal transmission period (or MCOT). In other words, the base station receives the reception result of the terminal for the downlink data transmitted in the reference subframe or the reference slot, and among the received reception results, increases or minimizes the size of CW_p according to the NACK ratio (Z). I can.

2, the contention period change reference slot for the channel access procedure 270 is the time point 270 at which the base station initiates the channel access procedure, and the above-described N in order for the base station to perform the channel access procedure. It may be the first transmission period 240 (hereinafter, slot or subframe) of the most recently transmitted downlink signal transmission period 230 through the unlicensed band at the time when the value is selected or immediately before the selection.

When the base station cannot report and receive the reception result for the downlink data channel transmitted in the first slot 240 of the transmission interval 230, the most recent downlink signal transmitted before the downlink signal transmission interval 230 The first subframe of the transmission period may be a reference subframe. The above-described case is illustratively, when the time interval between the first subframe and the time point 270 at which the base station initiates the channel access procedure is less than n slots or subframes, that is, the terminal with respect to the above-described first subframe 240 It may be the case that the base station initiates the channel access procedure before the time when the downlink data channel reception result can be reported. That is, the time point 270 when the base station starts the channel access procedure, the time point at which the base station selects the aforementioned N value to perform the channel access procedure, or immediately before the downlink data transmitted in the reference subframe 240 When the reception result is not received from the terminal, the base station may determine the first subframe of the most recently transmitted downlink signal transmission interval among the reception results for the downlink data channel previously received from the terminals as the reference subframe. I can. And the base station uses the above-described downlink data reception result received from the terminals for the downlink data transmitted through the downlink data channel in the reference subframe, the contention interval size used in the above-described channel access procedure 270 Can judge.

For example, the base station may transmit a downlink signal through a channel access procedure (eg, CW_p=15) set through a channel access priority type 3 (p=3). At this time, the base station, of the downlink signals transmitted through the unlicensed band, the reception result of at least 80% of the reception results of the terminal for downlink data transmitted to the terminal through the downlink data channel in the first subframe as NACK. If it is determined, the contention period may be increased from the initial value (CW_p=15) to the next contention period value (CW_p=31).

If the reception result of 80% or more of the reception result of the terminal is not determined as NACK, the base station may maintain the value of the contention period as the existing value or change to the initial value of the contention period. In this case, the change of the contention period may be applied in common to all types of channel access priority, or may be applied only to the type of channel access priority used in the channel access procedure. At this time, in the reference subframe or the reference slot for determining the contention interval size change, among the reception results for the above-described downlink data transmitted or reported by the terminal to the base station for downlink data transmitted through the downlink data channel, the above A method of determining a reception result that is effective for determining the size change of the contention section, that is, a method of determining the Z value may be as follows.

When the base station transmits one or more codewords or TBs to one or more terminals in the above-described reference subframe or reference slot, the base station transmits or reports the TB received in the above-described reference subframe or reference slot. Among the results, the Z value can be determined by the ratio of NACK. For example, when two codewords or two TBs are transmitted to one terminal in a reference subframe or a reference slot, the base station receives or receives a downlink data signal reception result for the aforementioned two TBs from the terminal. I can. Of the two reception results described above, when the ratio (Z) of NACK is equal to or greater than a threshold value (eg, Z=80%) defined in advance or set between the base station and the terminal, the base station determines the aforementioned contention interval size. Can be changed or increased.

When the terminal bundles downlink data reception results for one or more subframes (eg, M subframes) including the above-described reference subframe or slot and transmits or reports to the base station, the base station It can be determined that M number of reception results have been transmitted. In addition, the base station may determine the Z value based on the ratio of NACK among the above-described M reception results, and change, maintain or initialize the contention interval size.

In addition, when the reference subframe is a reception result for the second slot among two slots constituting one subframe, the base station includes the above-described reference subframe (that is, the second slot) and downlink data received in the next subframe. The above-described Z value may be determined based on the ratio of NACK among the reception results transmitted or reported by the terminal to the base station.

In addition, when scheduling information or downlink control information for a downlink data channel transmitted by a base station is transmitted in the same cell or frequency band as the cell or frequency band in which the downlink data channel is transmitted, or downlink control information transmitted by the base station When scheduling information or downlink control information for a link data channel is transmitted through an unlicensed band, but is transmitted in a cell different from the cell in which the downlink data channel is transmitted or at a different frequency, the terminal When it is determined that the reception result of the downlink data received in the slot has not been transmitted, or when the reception result of the above-described downlink data transmitted by the terminal is determined to be DTX, NACK/DTX, or any state, the base station May determine the above-described Z value by determining the reception result of the terminal as NACK.

In addition, when scheduling information or downlink control information for a downlink data channel transmitted by a base station is transmitted through a licensed band, the reception result for the aforementioned downlink data transmitted by the terminal is DTX, or NACK/DTX, or When it is determined to be any state, the base station may not include the above-described reception result of the terminal in the reference value Z of the contention period variation. In other words, the base station may ignore the above-described reception result of the terminal and determine the Z value.

In addition, when the base station transmits scheduling information or downlink control information for a downlink data channel through a licensed band, in the downlink data reception result for a reference subframe or a reference slot transmitted or reported by the terminal to the base station, When the base station does not actually transmit downlink data (no transmission), the base station may determine the Z value by ignoring a reception result transmitted or reported by the terminal for the aforementioned downlink data.

In the 5G system, it is necessary to flexibly define and operate the frame structure in consideration of various services and requirements. As an example, it may be considered that each service has a different subcarrier spacing according to requirements. In the current 5G communication system, a method of supporting a plurality of subcarrier spacing can be determined using [Equation 1] as follows.

Here, f ₀ denotes a basic subcarrier spacing of the system, and m may denote an integer scaling factor. For example, if f ₀ is 15 kHz, a set of subcarrier intervals that a 5G communication system can have may consist of 3.75 kHz, 7.5 kHz, 15 kHz, 30 kHz, 60 kHz, 120 kHz, 240 kHz, 480 kHz, etc. . In an embodiment, the usable subcarrier spacing Set may be different depending on the frequency band. For example, 3.75 kHz, 7.5 kHz, 15 kHz, 30 kHz, and 60 kHz may be used in a frequency band of 6 GHz or lower, and 60 kHz, 120 kHz, and 240 kHz may be used in a frequency band of 6 GHz or higher.

The length of the OFDM symbol may vary according to the subcarrier spacing constituting the OFDM symbol. This is because the subcarrier spacing and the length of the OFDM symbol have an inverse relationship with each other as a characteristic of the OFDM symbol. For example, when the subcarrier spacing is doubled, the symbol length is shortened to 1/2, and conversely, when the subcarrier spacing is decreased to 1/2, the symbol length may be doubled.

Next, a resource area through which a data channel is transmitted in a 5G communication system will be described.

3 is a diagram illustrating a resource region through which a data channel is transmitted in a 5G communication system. Specifically, FIG. 3 is a diagram illustrating a downlink to uplink scheduling method and a resource region in an NR or 5G system according to an embodiment.

The UE may monitor or search for the PDCCH 310 in a downlink control channel (hereinafter referred to as PDCCH) region (hereinafter referred to as control resource set (CORESET) to search space (SS)) set through an upper signal from the base station. In this case, the downlink control channel region may be composed of the time domain 314 and the frequency domain 312 information. In addition, the time domain 314 information may be set on a symbol basis, and the frequency domain 312 information may be set on a RB or RB group basis. If the UE detects the PDCCH 310 in the slot i 300, the UE may acquire downlink control information (DCI) transmitted through the detected PDCCH 310. The terminal may obtain scheduling information for a downlink data channel or an uplink data channel through the received downlink control information (DCI). In other words, the above-described DCI includes resource region (or PDSCH transmission region) information in which the terminal should receive a downlink data channel (hereinafter referred to as PDSCH) transmitted from the base station, or the terminal is allocated from the base station for uplink data channel (PUSCH) transmission. At least one of resource area information may be included.

An embodiment of a case in which the UE is scheduled to transmit an uplink data channel (PUSCH) is as follows. The terminal receiving the DCI may obtain the slot index or offset information (K) for receiving the PUSCH through the DCI, and determine the PUSCH transmission slot index. Referring to FIG. 3, for example, the UE schedules to transmit a PUSCH in slot i+K 305 through the received offset information (K) based on the slot index i (300) at which the PDCCH 310 is received. It can be judged as received. In this case, the UE may determine a PUSCH start symbol or time in slot i+K 305 or slot i+K based on the received offset information (K) based on the CORESET receiving the PDCCH 310. In addition, the UE may obtain information on the PUSCH transmission time-frequency resource region 340 in the PUSCH transmission slot 305 through the above-described DCI. In this case, the PUSCH transmission frequency resource region information 330 may be group-unit information of PRB to PRB.

Meanwhile, the above-described PUSCH transmission frequency resource domain information 330 is included in an initial uplink bandwidth (initial BW, BandWidth) or an initial uplink bandwidth part (initial BWP, BandWidth Part) determined or set by the terminal through an initial access procedure. It may be an area to be used. When the UE is configured with an uplink bandwidth (BW, BandWidth) or an uplink bandwidth part (BWP, BandWidth Part) through an upper signal, the above-described PUSCH transmission frequency resource domain information 330 is an uplink set through an upper signal. It may be a region included in a bandwidth (BW, BandWidth) or an uplink bandwidth part (BWP, BandWidth Part).

The PUSCH transmission time resource region information 325 may be symbol or group unit information of a symbol, or information indicating absolute time information. In this case, the PUSCH transmission time resource region information 325 may be expressed as a PUSCH transmission start time or symbol and a length of a PUSCH or a PUSCH end time or a combination of symbols, and may be included in DCI as one field or value. In this case, the PUSCH transmission time resource region information 325 may be included in the DCI as a field or value representing each of the PUSCH transmission start time or symbol and the length of the PUSCH or the PUSCH end time or symbol. The UE may transmit the PUSCH in the PUSCH transmission resource region 340 determined through the above-described DCI.

Hereinafter, a downlink control channel in an NR or 5G communication system will be described in more detail with reference to the drawings.

4 is a diagram showing an example of a control region (Control Resource Set, CORESET) in which a downlink control channel is transmitted in an NR or 5G wireless communication system. Referring to FIG. 4, two control regions (control region #1 401, control region #2 402) are set within a bandwidth portion 410 of the terminal as a frequency axis and one slot 420 as a time axis.

The control regions 401 and 402 may be set in a specific frequency resource 403 within the entire terminal bandwidth portion 410 on the frequency axis. The time axis may be set to one or more OFDM symbols, and this may be defined as a control region length (Control Resource Set Duration, 404). In FIG. 4, for example, control region #1 401 is set to a control region length of 2 symbols, and control region #2 402 is set to a control region length of 1 symbol.

The control region in 5G may be configured through higher layer signaling (eg, system information, master information block (MIB), radio resource control (RRC) signaling) provided by the base station to the terminal. Setting a control region to a terminal may mean providing information such as a control region identifier, a frequency position of the control region, and a symbol length of the control region. For example, the control area setting may include the following information.

로 가지는 6 PRB 그룹을 의미하며, 여기서

는 BWP 시작지점을 나타낼 수 있다. 비트맵의 최상위 비트는 첫번째 그룹을 지시하며 오름차순으로 설정될 수 있다.In Table 3, the tci-StatesPDCCH (hereinafter referred to as TCI state) configuration information is one or more SS (Synchronization Signal)/PBCH (Physical It may include information of a Broadcast Channel) block index or a Channel State Information Reference Signal (CSI-RS) index. In addition, the frequencyDomainResources setting information may set the frequency resource of the corresponding CORESET as a bitmap. Here, each bit may indicate a group of 6 PRBs that do not overlap. The first group is the first PRB index

Branch with means 6 PRB groups, where

May indicate the BWP starting point. The most significant bit of the bitmap indicates the first group and may be set in ascending order.

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 an NR or 5G communication system according to an embodiment. According to FIG. 5, a basic unit of time and frequency resources constituting a control channel may be called a Resource Element Group (REG) 503, wherein the REG 503 is 1 OFDM symbol 501 on the time axis and 1 PRB on the frequency axis. (Physical Resource Block, 502), that is, it may be defined as 12 subcarriers. The above-described REG 503 may be concatenated to configure a downlink control channel allocation unit.

As shown in FIG. 5, when a basic unit to which a downlink control channel is allocated in 5G is a control channel element (CCE) 504, one CCE 504 may be composed of a plurality of REGs 503. When the REG 503 shown in FIG. 5 is described as an example, the REG 503 may be composed of 12 REs, and when 1 CCE 504 is composed of 6 REGs 503, 1 CCE 504 ) Can be composed of 72 REs. 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 divided into one or more CCEs 504 according to an aggregation level (AL) within the control region. It can be mapped and transmitted. The CCEs 504 in the control region are classified by numbers, and the numbers 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 a demodulation reference signal (DMRS) 505, which is a reference signal for decoding them, is mapped. . As illustrated in FIG. 5, three DMRSs 505 may be transmitted in 1 REG 503.

The number of CCEs required to transmit the PDCCH may be 1, 2, 4, 8, or 16 depending on the aggregation level (AL), and the number of different CCEs indicates 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, and a search space indicating a set of CCEs may be used to aid in such blind decoding. The search space is a set of downlink control channel candidates (Candidates) consisting of CCEs to which the UE should attempt decoding on a given aggregation level. In an embodiment, since there are various aggregation levels that make one bundle of 1, 2, 4, 8, 16 CCEs, the terminal may have a plurality of search spaces. The search space set may be defined as a set of search spaces at all set aggregation levels.

The search space may be classified into a common search space and a UE-specific search space. In order to receive common control information such as dynamic scheduling or paging message for system information, a certain group of UEs or all UEs may examine the common search space of the PDCCH. For example, PDSCH scheduling allocation information for transmission of an SIB including cell operator information, etc. may be received by examining a common search space of the PDCCH. In the case of a common search space, since a certain group of UEs or all UEs must receive the PDCCH, it can be defined as a collection of pre-promised CCEs. The scheduling allocation information for the UE-specific PDSCH or PUSCH may be received by examining the UE-specific search space of the PDCCH. The terminal-specific search space may be terminal-specifically defined based on a function of the identity of the terminal and various system parameters.

In 5G, a parameter for the discovery space of the PDCCH may be set from the base station to the terminal based on higher layer signaling (eg, SIB, MIB, RRC signaling). For example, the base station has the number of PDCCH candidates at each aggregation level L, the monitoring period for the search space, the monitoring occasion per symbol in the slot for the search space, the search space type (common search space or terminal-specific search space), and the corresponding The combination of the DCI format and RNTI to be monitored in the search space, and the control region index to monitor the search space can be set to the terminal. For example, the above-described setting information may include the following information.

According to the configuration information, the base station may set one or a plurality of search space sets to the terminal. For example, the base station may set search space set 1 and search space set 2 to the terminal, and set to monitor DCI format A scrambled with X-RNTI in search space set 1 in a common search space, and search space set 2 DCI format B scrambled with Y-RNTI can be set to be monitored in a UE-specific search space.

According to the above-described setting information, one or a plurality of search space sets may exist in a common search space or a terminal-specific search space. For example, search space set #1 and search space set #2 may be set as a common search space, and search space set #3 and search space set #4 may be set as a terminal-specific search space.

In the common search space, a combination of the following DCI format and RNTI can be monitored.

- 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.

- 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

The RNTIs specified above may follow the definitions and uses below.

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

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

- CS-RNTI (Configured Scheduling RNTI): For semi-statically configured UE-specific PDSCH scheduling

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

- P-RNTI (Paging RNTI): PDSCH scheduling for paging transmission

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

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

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

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

- TPC-SRS-RNTI (Transmit Power Control for SRS RNTI): Used to instruct the power control command for SRS

In 5G, a plurality of search space sets may be set with different parameters (eg, DCI format). Accordingly, the set of search space sets monitored by the terminal may vary at each time point. For example, if search space set #1 is set to the X-slot period, search space set #2 is set to the Y-slot period, and X and Y are different, then the terminal will use search space set #1 in a specific slot. Both set #2 can be monitored, and in a specific slot, one of search space set #1 and search space set #2 can be monitored.

When a plurality of search space sets are set in the terminal, the following conditions may be considered in a method of determining a 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 candidate groups per slot in a cell set to a subcarrier interval of 15·2 ^μ kHz, and may be defined as shown in the following table.

[Condition 2: Limit the maximum number of CCE]

The number of CCEs constituting the entire search space per slot may not exceed C ^μ . Here, the entire search space may mean the entire CCE set corresponding to the union region of a plurality of search space sets. C ^μ may be defined as the maximum number of CCEs per slot in a cell set to a subcarrier interval of 15·2 ^μ kHz, and may be defined as shown in the following table.

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

According to the settings of the search space sets of the base station, there may be a case where the above-described condition A is not satisfied at a specific time point. If the above-described condition A is not satisfied at a specific point in time, the terminal may select and monitor only a part of the set of search spaces set to satisfy condition A at the point in time, and the base station may transmit the PDCCH to the selected search space set. .

The following method can be followed as a method of selecting some of the search spaces from the set of all search spaces.

[Method 1]

If condition A for the PDCCH is not satisfied at a specific time point (or slot), the UE (or the base station) selects a search space set in which the search space type is set as a common search space among the search space sets existing at the time point. -It is possible to preferentially select a set of search spaces set as a specific search space.

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

In an NR or 5G communication system, a base station or a terminal may transmit and receive signals in a broadband unlicensed band, and the broadband unlicensed band may be configured in a subband (eg, 20MHz) unit. The base station and the terminal may perform a channel access procedure in units of subbands to occupy an unlicensed band, and at least one of all subbands or one subband or consecutive subbands in an idle state according to the result of the channel access procedure. By connecting to the unlicensed band in the manner of, it is possible to perform set signal transmission. Meanwhile, in the NR system, since the downlink control channel region (CORESET to SS) is set for each BWP, if the available subband is changed according to the result of the channel access procedure, the PDCCH monitoring (Monotoring) candidate group (Candidate) may be omitted. Therefore, unlike the NR system, the configuration of the downlink control channel region for the wideband unlicensed band needs to be changed in a manner that considers the subband.

In the present disclosure, in a base station and a terminal configured to receive or transmit a downlink signal or an uplink signal in a broadband unlicensed band, a method for the base station to set a control channel region to the terminal is proposed. More specifically, a method and apparatus for instructing (or changing or adjusting) control channel region setting information in consideration of subbands, and changing or adjusting control channel region setting information using a result of a channel access procedure are proposed.

Hereinafter, the method and apparatus proposed in the embodiments of the present disclosure are not limited to and applied to each embodiment, and a control channel region for PDCCH monitoring or discovery using all or a combination of some of the embodiments proposed in the invention. It can be used in a method and apparatus for setting or determining. In addition, in an embodiment of the present disclosure, a case in which a base station configures a control channel region in a subband-based broadband unlicensed band will be described as an example, but this is exemplary, and the present disclosure provides a multi-carrier or carrier aggregation ( Carrier aggregation) may also be applicable when configuring a control channel region in a wideband system such as transmission. In addition, it may be applicable to the case of setting the control channel region in a single carrier or single band system in addition to the broadband. In addition, in the embodiment of the present disclosure, the description will be made on the assumption of a base station and a terminal operating in an unlicensed band, but not only an unlicensed band, but also a base station and a terminal operating in a licensed band or a shared spectrum. The method and apparatus proposed in can be applied.

[Example 1]

In this embodiment, a method for a base station to set a control channel region to a terminal in a broadband unlicensed band is proposed. More specifically, according to the present embodiment, the control channel region set in the bandwidth portion may be included in a specific subband, and the same control channel region setting information set in the specific subband may be used in other subbands.

6 is a diagram for describing a method of setting a control channel region according to an exemplary embodiment. The operation of the embodiment will be described with reference to FIG. 6 as follows.

The base station and the terminal transmitting and receiving signals in the broadband unlicensed band are configured to perform the above-described channel access procedure on a subband basis, and then access the idle subband according to the result of the channel access procedure to perform PDCCH/PDSCH transmission. Assume a base station. Here, the subband of the unlicensed band that can be accessed refers to at least one subband in an idle state. The base station may set the control channel region 607 within the bandwidth part 600. In this case, the set control channel region may be included only in a specific reference subband 601.

In an embodiment, the reference subband may be determined or set as the lowest subband index, the subband index including the SS/PBCH block, or the subband index including CORESET#0. Alternatively, in an embodiment, the base station may set the subband index to the terminal through higher signaling or control channel. Control channel region setting information of the subbands 602, 603, and 604 other than the reference subband may be the same as control channel region setting information included in the reference subband. In this case, the control channel region index applied to each subband may be the same, and the number of PDCCH candidate groups may be set within the set maximum number of PDCCH candidate groups. In the following, a method of setting a frequency resource is proposed when control channel region information set in a specific subband can be identically obtained in other subbands.

<Example 1-1>

7 is a diagram illustrating a method of setting a frequency resource according to an embodiment of the present disclosure. The operation of the embodiment will be described with reference to FIG. 7 as follows.

In the NR, the frequency resource of the control channel region in the bandwidth portion is set as a bitmap, as described above, and the most significant bit may mean the first 6 PRB bundle group 705 after the start PRB of the bandwidth portion. At this time, as in the operation of the above-described embodiment, after limiting the control channel region setting of the bandwidth portion to the reference subband 701, when the other subband 702 has the same control channel region setting information, the frequency resource is set. The bits may indicate different positions for each subband. An exemplary description with reference to FIG. 7 is a frequency resource position indicated by the most significant bit 708 of the bitmap in the reference subband 701 and the most significant bit 710 of the bitmap indicated in a subband 702 different from that indicated by the reference subband 701. The location of the frequency resource may be different. Accordingly, a method of determining and changing (or resetting) the bitmap setting of the frequency resource domain may be required, and will be described in detail below.

[Method 1] How to determine the bitmap for each PRB bundle group

When the base station and the terminal have the same bitmap indicating the control region frequency resource set in the reference subband, the most significant bit is the first X PRB after the start PRB of each subband (e.g. X=6) It can be determined that it indicates a group group. For example, exemplarily described with reference to FIG. 7, the most significant bit 708 of the frequency resource bitmap 700 of the control region set in the reference subband 701 is the start PRB of the reference subband 701 It may mean the first 6 PRB bundle group 705 after (707).

On the other hand, when the same bitmap is set in a subband 702 other than the reference subband 701, the most significant bit 710 is the first 6 PRB bundle group 706 after the start PRB 709 of the other subband 702. Can mean ). To this end, the base station may set a separate bitmap for the subband, which may be included in the control channel region information or in configuration information other than the control channel configuration information. Alternatively, the base station may indicate (or change) the method of determining the bitmap of the terminal using the downlink control channel. If there is a gap between subbands, the base station may set the gap information to the terminal as an upper signal. In this case, the above-described gap information may be defined in advance between the base station and the terminal, and the gap may be varied based on at least one of the size of the subband or the size of the carrier. Here, the gap may mean a subcarrier or PRB in which the UE does not receive at least a downlink control channel. In this case, the above-described gap information may be transmitted to the terminal through the control channel configuration information, but may be included in configuration information other than the above-described control channel configuration information, or may be transmitted through a downlink control channel. Upon receiving the gap information, the terminal may determine bit information of the bitmap in consideration of the gap. Illustratively described with reference to FIG. 7, in the case of a terminal receiving the gap section information 715, after determining the position of the start PRB 713 of the other subband 711 in consideration of the gap information 715, the first 6 The PRB bundle group 714 can be determined.

[Method 2] 1 PRB unit bitmap setting

When indicating the frequency resource of the control channel domain as a bitmap, the base station may set each bit of the bitmap to indicate one PRB. When the bitmap is configured in units of 1 PRB, the most significant bit of the bitmap representing the control region frequency resource may indicate the same position in each subband. To this end, the base station may set a separate bitmap for the subband, which may be included in the control channel region information or in configuration information other than the control channel configuration information. Alternatively, the base station may indicate (or change) the method of determining the bitmap of the terminal using the downlink control channel. If there is a gap between subbands, the UE may receive the above-described gap information, and may determine a start PRB position 717 in a subband other than the reference subband in consideration of the gap information 716. .

[Method 3] Subband-based PRB bundle group index setting

The base station may set an X PRB bundle group (eg, X=6) based on the start PRB in the subband. For example, the most significant bit of the bitmap for setting the frequency resource set in the reference subband 718 may indicate 6 PRB bundle groups 720 from the start PRB 723 of the reference subband 718. Likewise, in the other subband 719 having the same control channel configuration information, the most significant bit of the bitmap may indicate the 6PRB bundle group 721 from the start PRB 724 of the other subband 719. Accordingly, the 6 PRB bundle group index indicated by the bit of the bitmap in the control channel configuration information of each subband may indicate the same resource in each subband. To this end, the base station may set a separate bitmap for the subband, which may be included in the control channel region information or in configuration information other than the above-described control channel configuration information. Alternatively, the base station may indicate (or change) the method of determining the bitmap of the terminal using the downlink control channel. If there is a gap between subbands, the UE may receive the above-described gap information, and may determine a start PRB position in a subband other than the reference subband in the above-described manner in consideration of the gap information.

[Example 2]

In this embodiment, a method for a base station to set a control channel region to a terminal in a broadband unlicensed band is proposed. More specifically, the present embodiment proposes a method and apparatus in which a control channel region set based on a bandwidth portion includes all subbands.

8A is a diagram illustrating a method of setting a control channel region according to an embodiment. The operation of the embodiment will be described with reference to FIG. 8A as follows.

The base station and the terminal transmitting and receiving signals in the broadband unlicensed band are configured to perform the above-described channel access procedure on a subband basis, and then access the idle subband according to the result of the channel access procedure to perform PDCCH/PDSCH transmission. Assume a base station. Here, the subband of the unlicensed band that can be accessed refers to at least one subband in an idle state. The base station may set the control channel region 806 within the bandwidth portion 800. In this case, the set control channel region may include all subbands. In other words, the frequency resource of the control channel region set in the bandwidth portion may include all subbands. According to the embodiment, there is an advantage in that it is possible to set the control area of the broadband unlicensed band based on the existing NR. However, when the number of accessible subbands decreases due to a failure of the channel access procedure, the number of monitorable PDCCH candidate groups set in the bandwidth portion may decrease. Accordingly, in order to guarantee PDCCH decoding performance, a method of preventing the number of PDCCH candidate groups from decreasing due to a channel access procedure or a gap between subbands may be required, and a detailed method will be described below.

<Example 2-1>

When at least one CCE (or REG) constituting the PDCCH candidate group is lost due to a result of performing a channel access procedure or a gap between subbands, the base station punctures a CCE (or REG) set in a region that cannot be transmitted. ), the PDCCH can be transmitted. The UE may perform PDCCH decoding based on CORESET information set before puncturing from the base station.

<Example 2-2>

개의 PDCCH 후보군을 설정할 수 있다. 이때, 기지국은 가장 낮은(또는 높은) 인덱스를 가지는 적어도 하나 이상의 서브밴드, 또는 적어도 하나 이상의 특정 서브밴드에 대해서는 PDCCH 후보군의 개수 M을 넘지 않는 범위 내에서

개 이상의 PDCCH 후보군을 설정할 수도 있다. 또한, 기지국은 CCE 인덱스 설정 시, CCE 개수를 대역폭 부분이 아닌 서브밴드 별로 설정할 수 있다. 예를 들어, 기지국은 대역폭 부분에 N_CCE개의 CCE를 설정했을 때, j번째 서브밴드에는 N_{CCE , j}개의 활용가능한 CCE를 설정할 수 있다. 또한, 기지국은 N_{CCE , j}을 기반으로 j번째 서브밴드의 CCE 인덱스를 설정할 수 있다. When setting the CCE index, the base station may set the number of PDCCH candidate groups for each aggregation level for each subband. For example, if the number of subbands is M and the number of PDCCH candidates for the aggregation level L is N, the base station is at least in each subband.

PDCCH candidate groups can be set. At this time, the base station is within a range not exceeding the number M of PDCCH candidate groups for at least one or more subbands having the lowest (or high) index, or at least one specific subband.

It is also possible to set more than one PDCCH candidate group. In addition, when setting the CCE index, the base station may set the number of CCEs for each subband rather than a bandwidth part. For example, when the base station configures N _CCEs in the bandwidth portion, N _{CCEs and j} available CCEs in the j-th subband may be configured. In addition, the base station may set the CCE index of the j-th subband based on N _{CCE and j} .

Meanwhile, when the base station wants to perform CCE-to-REG mapping in an interleaved manner, the base station may limit the CCE-to-REG mapping for each subband. For example, when the base station is to have a single N _REG REG bandwidth in part, in the j-th subband N _{REG It} can have _j REGs. In this case, the base station may configure the CCE of subband _j by using N _{REG j} when CCE-to-REG mapping in an interleaved manner.

<Example 2-3>

In this embodiment, a method for the base station to change the PDCCH candidate group configuration after performing the channel access procedure will be described. It will be described with reference to FIG. 8B as follows. When at least one CCE (or REG) constituting the PDCCH candidate group is lost due to a result of performing a channel access procedure or a gap between subbands, the PDCCH candidate group N106 may not be used in the corresponding slot N103. Meanwhile, the base station may reset the PDCCH candidate group by using the CCE located in the transmittable subband N102 after at least one slot (N104) (N107). For example, in slot n (N103), the base station may set a PDCCH candidate group of aggregation level 4 in subband #0 (N101) and subband #1 (N102). In this case, when it is determined that subband #0 (N101) is not an idle channel as a result of performing the channel access procedure, the base station may not use the PDCCH candidate group N106 of aggregation level 4 in slot n (N103). However, from slot n+1 (N104), the base station may use the PDCCH candidate group N107 of aggregation level 2 by utilizing the CCE located in the transmittable subband #1 (N102). At this time, if the base station can determine (or imply) the result of performing the channel access procedure to the terminal through downlink control information or a reference signal, the above-described PDCCH candidate group configuration change is instructed based on the result of performing the channel access procedure. It may be possible to do it.

<Example 2-4>

In the present embodiment, it is assumed that the base station can cause the terminal to determine (or imply) the result of performing the channel access procedure through a control channel or a reference signal. Through this, the terminal receiving or determining the result of performing the channel access procedure for each subband by the base station (or an indicator indicating whether or not the channel is occupied for each subband) is performed by performing the PDCCH monitoring operation only on at least one idle subband as a result of the channel access procedure of the base station. Can be done. In this case, the base station may change the number of REGs from a bandwidth partial basis to a subband to perform PDCCH monitoring during interleaver CCE-to-REG mapping. In other words, the CCE may be interleaved within at least one or more subbands to perform PDCCH monitoring, not in the bandwidth part, to be CCE-to-REG mapping. If the terminal does not receive the result of performing the channel access procedure, the base station may not change the method of setting the number of REGs.

<Example 2-5>

If the base station loses at least one CCE (or REG) or RB or RE constituting the PDCCH candidate group due to a result of performing a channel access procedure or a gap between subbands, the base station may not transmit the corresponding PDCCH candidate group.

[Example 3]

In this embodiment, a method for a base station to set a control channel region to a terminal in a broadband unlicensed band is proposed. More specifically, a method and apparatus for setting a control channel region for each subband is proposed.

9 is a diagram for describing a method of setting a control channel region according to an embodiment. The operation of the embodiment will be described with reference to FIG. 9 as follows.

The base station and the terminal transmitting and receiving signals in the broadband unlicensed band are configured to perform the above-described channel access procedure on a subband basis, and then access the idle subband according to the result of the channel access procedure to perform PDCCH/PDSCH transmission. Assume a base station. Here, the subband of the unlicensed band that can be accessed refers to at least one subband in an idle state. The base station may separately set the control channel region setting for each subband. More specifically, subbands #0 to #3 (901, 902, 903, and 904) may have control channel region numbers #1 to #4 (906, 907, 908, and 909), respectively. In this case, the control channel region setting for each subband may be the same or different. According to an embodiment, flexible control channel region setting for each subband may be possible. However, the number of control channel region numbers in the bandwidth portion may need to be increased.

[Example 4]

In this embodiment, a method is proposed in which a base station performs the above-described channel access procedure in units of subbands, and a terminal determines a subband to perform a PDCCH monitoring operation according to a result of performing the channel access procedure.

More specifically, the base station may perform a channel access procedure in units of subbands when the bandwidth or bandwidth portion of the allocated carrier is greater than a certain size (for example, 20 MHz). In this case, the base station may inform the UE of the result of performing the above-described channel access procedure through a downlink control channel or a reference signal. In addition, the base station may cause the terminal to determine (or imply) the result of performing the channel access procedure through a control channel or a reference signal. Through this, the terminal receiving or determining the result of performing the channel access procedure for each subband by the base station (or an indicator indicating whether or not the channel is occupied for each subband) is performed by performing the PDCCH monitoring operation only on at least one idle subband as a result of the channel access procedure of the base station. Can be done. A specific example is as follows.

[Method 1]

A terminal that has received or determined the result of performing the channel access procedure for each subband of the base station may perform PDCCH monitoring only for at least one or more subbands determined as idle bands.

[Method 2]

The UE that receives or determines the result of performing the channel access procedure for each subband of the base station may perform PDCCH monitoring only in the subband having the lowest (or highest) subband index among at least one or more subbands determined as idle bands. . As another method, the base station may perform PDCCH monitoring only for subbands including CORESET#0 to SS/PBCH blocks. As another method, the base station may monitor the PDCCH in a subband indicated through an upper signal or a control channel. In addition, the base station may perform PDCCH monitoring using one or more combinations of the above-described methods.

[Method 3]

The terminal that has received or determined the result of performing the channel access procedure for each subband by the base station may set at least one specific subband to perform PDCCH monitoring through a specific rule among at least one or more subbands determined as idle bands. For example, the terminal may determine a specific subband using at least a combination of a terminal number (UE ID), an RNTI value, and the number of idle subbands (K). For example, the UE may perform PDCCH monitoring in the subband of the index determined by mod (UE IDxRNTI, K).

If the base station does not receive or determine the result of performing the channel access procedure for each subband, the UE may perform PDCCH monitoring in all subbands. A terminal that has changed (or reset) a subband to perform PDCCH monitoring by a combination of at least one or more of the above-described methods by receiving or determining the result of performing the channel access procedure for each subband of the base station is changed at least within the maximum channel occupancy period. You can monitor the PDCCH with the (or reset) settings. In this case, the terminal may be changed (or reset) to perform PDCCH monitoring for all subbands after the maximum channel occupancy period. In addition, the UE and the base station may reset the CCE index based on the number of PDCCH candidates to be monitored or the number of CCEs after the subband to be monitored is changed (or reset).

[Example 5]

In this embodiment, a method of adjusting (or changing) or determining the number of PDCCH candidate groups for subbands for which PDCCH monitoring is to be performed is proposed.

More specifically, it is assumed that a terminal has received or determined a result of performing a channel access procedure for each subband by a base station (or an indicator indicating whether a channel is occupied by each subband). The UE may perform PDCCH monitoring only on at least one or more idle subbands using the received or determined information. Meanwhile, the number of PDCCH candidate groups that the UE can monitor per slot may be limited. Therefore, if the UE performs PDCCH monitoring only in an idle subband, a PDCCH candidate group that can be monitored set in a subband not performing PDCCH monitoring cannot be used, and the PDCCH transmission capacity may be reduced. Therefore, when the subband to monitor the PDCCH is changed (or reset) according to the result of performing the channel access procedure for each subband of the base station, the method of changing the number of PDCCH candidate groups for at least one or more subbands to be monitored (or reset) is May be needed. A specific example is as follows.

[Method 1]

으로 결정될 수 있다.When at least one subband to perform PDCCH monitoring is determined, the UE may adjust (or change) the number of PDCCH candidate groups using the determined number of subbands. For example, when the number of PDCCH candidates that can be monitored per set slot is M, and the number of subbands to perform PDCCH monitoring is N, PDCCHs that can be monitored in each of at least one or more subbands to be monitored The number of candidates is

Can be determined.

[Method 2]

The base station may indicate (or change) the number of PDCCH candidate groups of at least one or more subbands for the UE to perform PDCCH monitoring through a control channel. For example, the base station may indicate (or change) the number of PDCCH candidate groups of subbands for which the UE will perform PDCCH monitoring with information included in control information such as scheduling DCI (or UE specific DCI) or group common DCI. As another example, the UE may indicate (or change) the number of PDCCH candidate groups of the subband for which the UE will perform PDCCH monitoring through an indicator indicating whether or not the channel is occupied for each subband. As another example, the base station may inform the number of PDCCH candidate groups of subbands for which the UE will perform PDCCH monitoring by using the DMRS. For example, a specific DMRS sequence or resource location may be associated with the number of PDCCH candidates.

[Method 3]

When the UE adjusts the number of PDCCH candidate groups in a subband to perform PDCCH monitoring, the number of PDCCH candidate groups in a specific search space may not be adjusted (or changed). For example, the UE may adjust (or change) the number of PDCCH candidate groups only for a UE-specific search space. As another example, the UE may not adjust (or change) the number of PDCCH candidate groups only for a specific search space. For example, the UE may not adjust (or change) the number of PDCCH candidates for a search space including a common search space or DCI indicating a result of a channel access procedure or a search space including group common DCI monitoring.

[Method 4]

When the terminal determines or is instructed to adjust (or change) the number of PDCCH candidates for the subband to perform PDCCH monitoring, the base station and the terminal determine the application time of the adjusted (or changed) number of PDCCH candidates in a predetermined slot or time (or Timer). As another method, after the UE determines or is instructed to adjust (or change) the number of PDCCH candidates for the subband on which PDCCH monitoring is to be performed, the UE uplink controls the confirmation signal for the adjustment (or change) of the number of PDCCH candidates. It can be transmitted or confirmed to the base station using a signal or data signal or a reference signal.

If the UE fails to determine or is not instructed to adjust (or change) the number of PDCCH candidates for the subband to perform PDCCH monitoring, the UE may perform PDCCH monitoring using the initially set number of PDCCH candidates. When the terminal determines or is instructed to adjust the number of PDCCH candidates (or change) for the subband to perform PDCCH monitoring and adjusts (or changes) the number of PDCCH candidates by a combination of at least one of the above-described methods, the terminal is at least In the maximum channel occupancy period, PDCCH monitoring may be performed by setting the number of adjusted (or changed) PDCCH candidate groups. In this case, the UE may perform PDCCH monitoring by setting the number of PDCCH candidate groups initially set (or setting before adjusting the number of PDCCH candidate groups (or changing)) after the maximum channel occupancy period. In addition, the UE and the base station may adjust (or change) the number of PDCCH candidates to be monitored, and then reset the CCE index based on the changed number of PDCCH candidates or the number of CCEs.

[Example 6]

In this embodiment, a method for a base station to set a control channel region to a terminal in a broadband unlicensed band is proposed. More specifically, according to the present embodiment, a control channel region (or configuration information) set in the bandwidth portion may be included in a specific subband. The base station may set the control channel region setting information set in a specific subband to the terminal in the same (or shared or repeated) at least one or more subbands other than the specific subband. Hereinafter, a detailed description will be given of a method for the base station to set the same (or shared or repeated) control channel region setting information to the terminal in at least one subband.

[Method 1]

The base station instructs (or judges) the terminal to have the same (or shared or repeated) control channel region setting information in at least one or more subbands in the bandwidth portion or subbands scheduled from the base station using a specific control channel region index. I can. In other words, the terminal may determine that the control channel region setting information set in association with the control channel region index X from the base station is applied (or set) identically (or shared or repeated) in at least one or more subbands. In addition, the base station sets a separate subband index in the control channel region setting information to instruct (or determine) at least one subband index in which the same (or shared or repeated) control channel region setting information is set to the terminal. I can.

[Method 2]

The base station instructs (or judges) that the control channel configuration information associated with a specific search area index has the same (or shared or repeated) control channel area configuration information in at least one subband within at least one bandwidth portion or a subband scheduled from the base station. ). In addition, the base station may separately set the subband index in the search area setting to instruct the terminal (or determine) at least one subband index in which the same (or shared or repeated) control channel region setting information is set to the terminal. have. As another method, the base station uses an offset value from a specific PRB #Y (for example, common PRB #0) within the search area setting to apply the control channel configuration information equally (or shared or repeated). It is possible to instruct (or determine) the starting point of the frequency resource of the terminal. As another method, the base station uses an offset value from a specific PRB #X for each subband (for example, a start PRB for each subband) within the search area setting, and the control channel setting information is the same (or shared or repeated). The frequency resource start point of each subband to be applied may be indicated (or determined) to the UE.

[Method 3]

The terminal that received or determined the result of performing the channel access procedure for each subband of the base station may determine that it has the same (or shared or repeated) control channel region setting information in at least one or more subbands determined as an idle band (or transmission band). I can. At this time, if the result of performing the channel access procedure received by the terminal and the same (or shared or repeated) control channel setting information set from the upper level is different from the applied at least one subband setting information, the terminal accesses the channel received from the base station. At least one or more subband setting information to which the same (or shared or repeated) control channel region setting information is applied may be determined based on the execution result.

[Method 4]

The base station may indicate to the terminal whether or not the same (or shared or repeated) control channel region is set in the control information by bit signaling. A terminal that has received the same (or shared or repeated) transmission indicator may determine that the same information is repeated, and a terminal that does not receive the same information may determine that the control channel region monitoring is performed only for a specific subband.

[Example 7]

In this embodiment, a method of receiving a control signal in a plurality of control areas set by a base station by a terminal in a broadband unlicensed band is proposed. More specifically, according to the present embodiment, a control channel region (or configuration information) set in the bandwidth portion may be included in a specific subband. The base station may set the control channel region setting information set in a specific subband to the terminal in the same (or shared or repeated) at least one or more subbands other than the specific subband. Meanwhile, the terminal may receive a plurality of control information in a control channel region set to be identical (or shared or repeated) in a plurality of subbands. If the terminal can only receive (or decode or demodulate) some of the plurality of control information transmitted by the base station, the terminal can receive (or decode or demodulate) the control information based on the following rules.

[Method 1]

The terminal may receive (or decode or demodulate) X pieces of control information that can be received (or decoded or demodulated) from the lowest (or highest) subband index. As another method, the terminal may first receive (or decode or demodulate) the control information received in the subband index including CORESET #0. As another method, the UE may preferentially receive (or decode or demodulate) control information transmitted from a subband index including an SS/PBCH block. In addition, the terminal may determine X pieces of control information to be received (or decoded or demodulated) through a combination of at least one of the above-described methods.

10 is a flowchart illustrating an operation of a base station according to an embodiment. An operation of a base station according to an embodiment of the present disclosure will be described with reference to FIG. 10 as follows.

In step 1000, the base station may transmit a configuration related to transmission and reception of PDCCH, PDSCH, PUCCH, and PUSCH to the terminal through an upper signal. For example, the base station may transmit a PDCCH resource region for receiving downlink or uplink scheduling information, a CORESET setting, a search space setting, and the like to the terminal through an upper signal. In addition, the base station may transmit a configuration regarding PDSCH/PUSCH transmission/reception to the terminal through an upper signal, including offset information between the PDCCH reception slot and the PDSCH reception slot or PUSCH transmission slot, information on the number of repetitive transmissions of PDSCH or PUSCH, and the like.

In step 1010, the base station may additionally transmit setting information related to CORESET and search space for wideband unlicensed band operation through a control channel or an upper signal. For example, the base station may transmit information such as a frequency resource setting determination method in the CORESET setting, gap information between subbands, change (or adjustment) of the number of PDCCH candidate groups, or subbands to be monitored for PDCCH. At this time, it is also possible to transmit CORESET and search space-related configuration information transmitted to the terminal in step 1010 in step 1000.

In step 1030, the base station may perform control channel transmission by setting a CORESET and a search space instructed to the terminal.

11 is a flowchart illustrating an operation of a terminal according to an embodiment.

In step 1100, the UE receives the settings for transmission and reception of PDCCH, PDSCH, PUCCH, and PUSCH from the base station through an upper signal, and may set the transmission and reception of PDCCH, PDSCH, PUCCH, and PUSCH according to the received configuration information. For example, the UE may receive a PDCCH resource region for receiving downlink or uplink scheduling information from a base station, a CORESET setting, a search space setting, and the like, through an upper signal.

In step 1110, the terminal may additionally receive setting information related to a CORESET and a search space for operation of a wideband unlicensed band through a control channel or an upper signal. At this time, the setting information related to the CORESET and the search space in step 1110 may be included in the upper signal setting information transmitted in step 1100. For example, information such as a frequency resource setting determination method within a CORESET setting, a gap value between subbands, a change in the number of PDCCH candidate groups, or a subband to be monitored for PDCCH may be received.

In step 1120, it is determined whether the CORESET for the broadband unlicensed band and setting information related to the SS have been additionally received.

If it is determined in step 1120 that the CORESET and the search space setting in consideration of the subband for the broadband unlicensed band has not been received, the UE may receive the PDCCH based on the PDCCH monitoring setting preset in step 1130.

In step 1120, when it is determined that the CORESET and search space setting in consideration of the subband for the broadband unlicensed band has been received, the terminal receives the PDCCH based on the control channel region setting information set (or changed or indicated) by the base station in step 1140. can do.

Specifically, FIG. 12 is a block diagram illustrating an internal structure of a base station according to an embodiment of the present disclosure. As shown in FIG. 12, the base station of the present disclosure may include a processor 1210, a transceiver 1220, and a memory 1230. However, the components of the base station are not limited to the above-described example. For example, the terminal may include more or fewer components than the above-described components. In addition, the processor 1210, the transceiver 1220, and the memory 1230 may be implemented in the form of a single chip.

According to the above-described communication method of the base station, the transceiver 1220 and the processor 1210 may operate.

The transceiving unit 1220 may transmit and receive signals to and from the terminal. Here, the signal may include control information and data. To this end, the transceiver 1220 may include an RF transmitter that up-converts and amplifies a frequency of a transmitted signal, and an RF receiver that amplifies a received signal with low noise and down-converts a frequency. However, this is only an embodiment of the transmission/reception unit 1220, and components of the transmission/reception unit 1220 are not limited to the RF transmitter and the RF receiver.

Also, the transceiver 1220 may receive a signal through a wireless channel and output it to the processor 1210, and transmit the signal output from the processor 1210 through the wireless channel.

The processor 1210 may store programs and data required for operation of the base station. In addition, the processor 1210 may store control information or data included in a signal obtained from the base station. The processor 1210 may include a storage medium such as a ROM, RAM, a hard disk, a CD-ROM, and a DVD, or a memory formed of a combination of storage media.

The processor 1210 may control a series of processes so that the base station can operate according to the above-described embodiment of the present disclosure. According to some embodiments, the processor 1210 may perform a channel access procedure for an unlicensed band. For a specific example, the processor 1210 receives signals transmitted in the unlicensed band through the transmission/reception unit 1220, and a threshold value determined in advance by defining the strength of the received signal or a value of a function taking a bandwidth as a factor. Compared with, it is possible to determine whether the above-described unlicensed band is in an idle state. For another example, the processor 1210 changes or resets the control channel region and search space setting information of the base station according to the channel access procedure result or subband transmission, and accordingly, the transmission/reception unit 122 sets the downlink control channel. Can be sent.

The memory 1230 may store at least one of information transmitted/received through the above-described transmission/reception unit 1220 and information generated through the processor 1210. Also, the memory 1230 may store control information or data included in the acquired signal. The memory 1230 may be composed of a storage medium such as a ROM, a RAM, a hard disk, a CD-ROM, a DVD, or a combination of storage media. Also, the memory 1230 may be formed of a plurality of memories.

13 is a block diagram illustrating an internal structure of a terminal according to an embodiment of the present disclosure. As illustrated in FIG. 13, the terminal of the present disclosure may include a processor 1310, a transmission/reception unit 1320, and a memory 1330. However, the components of the terminal are not limited to the above-described example. For example, the terminal may include more or fewer components than the above-described components. In addition, the processor 1310, the transceiver 1320, and the memory 1330 may be implemented in the form of a single chip.

The transceiver 1320 may transmit and receive signals to and from the base station. The above-described signal may include control information and data. To this end, the transceiver 1320 may include an RF transmitter that up-converts and amplifies a frequency of a transmitted signal, and an RF receiver that amplifies a received signal with low noise and down-converts a frequency. In addition, the transmission/reception unit 1320 may receive a signal through a wireless channel, output it to the processor 1310, and transmit a signal output from the processor 1310 through a wireless channel.

The processor 1310 may control a series of processes so that the terminal can operate according to the above-described embodiment of the present disclosure. For example, the processor 1310 may receive a data signal including a control signal through the transceiver 1320 and may determine a reception result of the data signal. Thereafter, when the first signal reception result including the above-described data reception is to be transmitted to the base station at the above-described timing, the processor 1310 transmits the above-described first signal reception result to the base station through the transceiver 1320 at the determined timing. Can be sent to For another example, in the case of receiving change or reconfiguration information on the control channel region and serach space settings from the base station through the transceiver 1320, the processor 1310 accordingly transmits the base station from the transceiver 1320. It is possible to receive a downlink control channel and a data signal.

The memory 1330 may store at least one of information transmitted and received through the above-described transmission/reception unit 1320 and information generated through the processor 1310. Also, the memory 1330 may store control information or data included in the acquired signal. The memory 1330 may be formed of a storage medium such as a ROM, a RAM, a hard disk, a CD-ROM, a DVD, or a combination of storage media. Also, the memory 1330 may be formed of a plurality of memories.

Meanwhile, the embodiments of the present disclosure disclosed in the present specification and drawings are merely provided with specific examples to easily describe the technical content of the present disclosure and to aid understanding of the present disclosure, and are not intended to limit the scope of the present disclosure. That is, that other modified examples based on the technical idea of the present disclosure may be implemented is obvious to those of ordinary skill in the technical field to which the present disclosure belongs. In addition, each of the above-described embodiments may be combined and operated as necessary. For example, some of the methods proposed in the present disclosure may be combined with each other to operate a base station and a terminal. In addition, although the above-described embodiments were presented on the basis of 5G and NR systems, other systems such as LTE, LTE-A, LTE-A-Pro system, and V2X may also have other modifications based on the technical idea of the above-described embodiments. will be.

Claims (1)

In a method for transmitting a control channel by a base station in a wireless communication system,
Determining setting information for setting a control channel;
Transmitting the configuration information to the terminal based on higher layer signaling; And
And transmitting the control channel to the terminal based on the setting information.

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