KR102830400B1 - Method and apparatus for transmission and reception of data channel in wireless communication system - Google Patents

Abstract

The present disclosure relates to a method and device for transmitting and receiving data channels and control information in a wireless communication system. More specifically, it relates to a method for setting up an uplink data channel region and configuring uplink control information in a wideband unlicensed band. More specifically, it proposes a method for changing or resetting the uplink data channel region and uplink control information setting and location by considering an occupied subband.

Description

METHOD AND APPARATUS FOR TRANSMISSION AND RECEPTION OF DATA CHANNEL IN WIRELESS COMMUNICATION SYSTEM

The present disclosure relates to a wireless communication system, and more particularly, to a method and apparatus for transmitting and receiving data and control information in a wireless communication system. More particularly, the present disclosure relates to a wireless communication system, and more particularly, to a system and node for transmitting an uplink signal in an unlicensed band, or a system and node for receiving a downlink signal, and a method for setting a downlink data channel region and control information transmission in the node.

In order to meet the explosively increasing demand for wireless data traffic due to the commercialization of 4G communication systems and the increase in multimedia services, improved 5G communication systems or pre-5G communication systems are being developed. For this reason, 5G communication systems or pre-5G communication systems are also called Beyond 4G Network communication systems or Post LTE systems.

To increase the data transmission rate, 5G communication systems are being considered for implementation in ultra-high frequency (mmWave) bands (e.g., 60 gigahertz (GHz) bands). To mitigate the path loss of radio waves in ultra-high frequency bands and increase the transmission distance of radio waves, beamforming, massive MIMO, full-dimensional MIMO (FD-MIMO), array antenna, analog beam-forming, and large scale antenna technologies are being discussed in 5G communication systems.

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

Meanwhile, the Internet is evolving from a human-centered network where humans create and consume information to an Internet of Things (IoT) network where information is exchanged and processed between distributed components such as objects. IoE (Internet of Everything) technology, which combines IoT technology with big data processing technology through connection to cloud servers, is also emerging. In order to implement IoT, technological elements such as sensing technology, wireless communication and network infrastructure, service interface technology, and security technology are required, and recently, technologies such as sensor networks for connection between objects, machine-to-machine (M2M), and machine type communication (MTC) are being studied. In the IoT environment, intelligent IT (Internet Technology) services can be provided that collect and analyze data generated from connected objects to create new values for human life. IoT can be applied to fields such as smart homes, smart buildings, smart cities, smart cars or connected cars, smart grids, healthcare, smart home appliances, and advanced medical services through convergence and combination between existing IT (information technology) technologies and various industries.

Accordingly, various attempts are being made to apply 5G communication systems to IoT networks. For example, technologies such as sensor networks, machine-to-machine (M2M), and machine-type communication (MTC) are being implemented by 5G communication technologies using techniques such as beamforming, MIMO, and array antennas. The application of cloud radio access networks (cloud RAN) as a big data processing technology described above can also be considered an example of the convergence of 5G and IoT technologies.

The present disclosure relates to a method and device for setting up data channel transmission and reception and control information in a wireless communication system. In one embodiment of the present disclosure, a method for setting up an uplink data channel region and setting up and configuring uplink control information is proposed in a system and node for receiving a downlink signal through an unlicensed band or a system and node for transmitting an uplink signal.

A method and device for transmitting and receiving a data channel in a wireless communication system according to one embodiment may include a step of receiving information regarding data channel setup from a base station, a step of setting an uplink data channel region based on the information regarding the data channel setup, and a step of transmitting data including uplink control information setup to the base station through the set uplink data channel region.

FIG. 1 is a diagram illustrating an uplink and downlink time-frequency domain transmission structure of an NR or 5G communication system according to one embodiment of the present disclosure.
FIG. 2 is a diagram for explaining a channel access procedure in an unlicensed band according to one embodiment of the present disclosure.
FIG. 3 is a diagram illustrating a resource region in which a data channel is transmitted in an NR or 5G communication system according to one embodiment of the present disclosure.
FIG. 4 is a diagram illustrating an example of setting a control region of a downlink control channel in an NR or 5G communication system according to one embodiment of the present disclosure.
FIG. 5 is a diagram illustrating the structure of a downlink control channel in an NR or 5G communication system according to one embodiment of the present disclosure.
FIG. 6 is a diagram illustrating an example of transmitting an uplink signal without uplink scheduling information in an unlicensed band according to one embodiment of the present disclosure.
FIG. 7 is a diagram illustrating an example of setting uplink signal transmission in a guard band when a terminal performs uplink transmission in a wideband unlicensed band according to one embodiment of the present disclosure.
FIG. 8 is a diagram illustrating an example of setting uplink signal transmission in a guard band when a terminal performs uplink transmission in a wideband unlicensed band according to one embodiment of the present disclosure.
FIG. 9 is a diagram illustrating an example in which a terminal performs a channel access procedure for each subband in a wideband unlicensed band according to one embodiment of the present disclosure and transmits the results of performing the channel access procedure for each subband to a base station.
FIG. 10 is a diagram illustrating an example of a terminal determining an uplink control information position within a slot in which uplink transmission is performed in a wideband unlicensed band according to one embodiment of the present disclosure.
FIG. 11 is a diagram illustrating an example of a terminal changing the location of uplink control information according to an embodiment of the present disclosure.
FIG. 12 is a flowchart illustrating the operation of a base station according to an embodiment of the present disclosure.
FIG. 13 is a flowchart illustrating the operation of a terminal according to an embodiment of the present disclosure.
FIG. 14 is a diagram illustrating an example of receiving a downlink signal or transmitting an uplink signal when a terminal according to an embodiment of the present disclosure fails to receive a DCI indicating a slot format.
FIG. 15 is a block diagram illustrating the structure of a base station according to one embodiment of the present disclosure.
FIG. 16 is a block diagram illustrating the structure of a terminal according to one embodiment of the present disclosure.

Hereinafter, embodiments of the present disclosure will be described in detail with the accompanying drawings. In addition, when describing the present disclosure, if it is determined that a specific description of a related known function or configuration may unnecessarily obscure the gist of the present disclosure, the detailed description will be omitted. In addition, the terms described below are terms defined in consideration of the functions in the present disclosure, and these may vary depending on the intention or custom of the user or operator. Therefore, the definitions should be made based on the contents throughout this specification.

The advantages and features of the present disclosure, and the methods for achieving them, will become apparent by referring to the embodiments described in detail below together with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below and may be implemented in various different forms, and the embodiments are provided only to make the disclosure of the present disclosure complete and to fully inform a person having ordinary skill in the art to which the present disclosure belongs of the scope of the disclosure, and the present disclosure is defined only by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the attached 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 convey the gist of the present disclosure more clearly without obscuring it by omitting unnecessary descriptions.

For the same reason, some components in the attached drawings are exaggerated, omitted, or schematically illustrated. In addition, the size of each component does not entirely reflect the actual size. The same or corresponding components in each drawing are given the same reference numbers.

The advantages and features of the present disclosure, and the methods for achieving them, will become apparent by referring to the embodiments described in detail below together with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below and may be implemented in various different forms, and the embodiments are provided only to make the disclosure of the present disclosure complete and to fully inform a person having ordinary skill in the art to which the present disclosure belongs of the scope of the disclosure, and the present disclosure is defined only by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

At this time, it will be understood that each block of the processing flow diagrams and combinations of the flow diagrams can be performed by computer program instructions. These computer program instructions can be loaded onto a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing equipment, so that the instructions executed by the processor of the computer or other programmable data processing equipment create a means for performing the functions described in the flow diagram block(s). These computer program instructions can also be stored in a computer-available or computer-readable memory that can be directed to a computer or other programmable data processing equipment to implement the function in a specific manner, so that the instructions stored in the computer-available or computer-readable memory can also produce a manufactured article including an instruction means for performing the functions described in the flow diagram block(s). Since the computer program instructions may be installed on a computer or other programmable data processing apparatus, a series of operational steps may be performed on the computer or other programmable data processing apparatus to produce a computer-executable process, so that the instructions executing the computer or other programmable data processing apparatus may also provide steps for executing the functions described in the flowchart block(s).

Additionally, each block may represent a module, segment, or portion of code that contains one or more executable instructions for performing a particular logical function(s). It should also be noted that in some alternative implementation examples, the functions mentioned in the blocks may occur out of order. For example, two blocks shown in succession may in fact be performed substantially concurrently, or the blocks may sometimes be performed in reverse order, depending on the functionality they perform.

Here, the term '~ part' used in the present embodiment means a software or hardware component such as an FPGA or ASIC, and the '~ part' performs certain roles. However, the '~ part' is not limited to software or hardware. The '~ part' may be configured to be in an addressable storage medium and may be configured to reproduce one or more processors. Thus, as an example, the '~ part' includes components such as software components, object-oriented software components, class components, and task components, processes, functions, properties, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functions provided in the components and '~ parts' may be combined into a smaller number of components and '~ parts' or further separated into additional components and '~ parts'. In addition, the components and '~ parts' may be implemented to reproduce one or more CPUs in a device or a secure multimedia card. Additionally, in the embodiment, '~ part' may include one or more processors.

In the 5G system, support for various services is being considered compared to the existing 4G system. For example, the most representative services may include enhanced mobile broadband (eMBB) service, ultra-reliable and low latency communication (URLLC) service, massive machine type communication (mMTC) service, and evolved multimedia broadcast/multicast service (eMBMS). In addition, a system providing the URLLC service may be referred to as a URLLC system, and a system providing the eMBB service may be referred to as an eMBB system. In addition, the terms service and system may be used interchangeably.

In this way, multiple services can be provided to a user in a communication system, and in order to provide such multiple services to a user, a method and a device using the same may be required that can provide each service within the same time period according to its characteristics.

According to one embodiment of the present disclosure, by setting an uplink data channel region and control information by considering a subband in a system and node receiving a downlink signal or a system and node transmitting an uplink signal in a wireless communication system, uplink data channel reception and frequency use 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 base station may transmit downlink control information (DCI) including resource allocation information to which a downlink signal is transmitted to a terminal through a physical downlink control channel (PDCCH), so that the terminal may be configured to receive at least one downlink signal from among the downlink control information (e.g., Channel-State Information Reference Signal (CSI-RS)), a broadcast channel (Physical Broadcast CHannel (PBCH), or a downlink data channel (Physical Downlink Shared CHannel (PDSCH)).

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

If the configured downlink transmission is transmitted from the base station to the terminal through an unlicensed band, or if the configured uplink transmission is transmitted from the terminal to the base station through an unlicensed band, the transmitting device (base station or terminal) performs a channel access procedure (or LBT: listen-before talk) for the unlicensed band for which the signal transmission is configured before or immediately before the configured signal transmission start time, and if the unlicensed band is determined to be idle based on the result of performing the channel access procedure, the unlicensed band can be accessed to perform the configured signal transmission.

If, based on the results of the channel access procedure performed by the transmitting device, the unlicensed band is determined to be not idle or occupied, the transmitting device may not be able to access the unlicensed band and thus may not be able to transmit the configured signal.

The channel access procedure in an unlicensed band where signal transmission is set may generally be as follows. A transmitting device may receive a signal in the unlicensed band for a predetermined period of time or a period of time calculated according to a predefined rule (for example, a period of time calculated through at least one random value selected by a base station or a terminal). The transmitting device may determine an idle state of the unlicensed band by comparing the intensity of the received signal with a threshold value that is defined in advance or calculated by a function composed of at least one variable among a channel bandwidth, a bandwidth of a signal to be transmitted, the intensity of transmission power, a beamwidth of a transmission signal, etc.

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

In the case of 5G communication systems, various technologies have been introduced to support various services and high data transmission rates, such as retransmission by code block group unit and technology that can transmit uplink signals without uplink scheduling information. Therefore, when performing 5G communication through unlicensed bands, a more efficient channel access procedure that considers various variables may be required.

Wireless communication systems are evolving from the initial voice-oriented services to broadband wireless communication systems that provide high-speed, high-quality packet data services, such as 3GPP's HSPA (High Speed Packet Access), LTE (Long Term Evolution or E-UTRA (Evolved Universal Terrestrial Radio Access)), LTE-Advanced (LTE-A), 3GPP2's HRPD (High Rate Packet Data), UMB (Ultra Mobile Broadband), and IEEE's 802.16e. In addition, communication standards for 5G or NR (new radio) are being created as the 5th generation wireless communication system.

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

When a base station schedules data corresponding to an eMBB service to a terminal for a specific transmission time interval (TTI), and a situation arises where URLLC data needs to be transmitted in the TTI, some of the eMBB data may not be transmitted in the frequency band where the eMBB data has already been scheduled and transmitted, and the generated URLLC data may be transmitted in the frequency band. The terminal scheduled for eMBB and the terminal scheduled for URLLC may be the same terminal or different terminals. In this case, since some of the eMBB data that has already been scheduled and transmitted is not transmitted, the possibility of eMBB data being damaged increases. Therefore, a method for processing a signal received by a terminal scheduled for eMBB or a terminal scheduled for URLLC and a method for receiving a signal need to be determined.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the attached drawings. In addition, when describing the present disclosure, if it is determined that a specific description of a related function or configuration may unnecessarily obscure the gist of the present disclosure, the detailed description will be omitted. In addition, the terms described below are terms defined in consideration of the functions in the present disclosure, and may vary depending on the intention or custom of a user or operator. Therefore, the definitions should be made based on the contents throughout this specification. Hereinafter, a base station is an entity that performs resource allocation of a terminal, and may be at least one of an eNode B, a Node B, a BS (Base Station), a wireless access unit, a base station controller, or a node on a network. A terminal may include a UE (User Equipment), an MS (Mobile Station), a cellular phone, a smartphone, a computer, or a multimedia system capable of performing a communication function. In the present disclosure, a downlink (DL) may refer to a wireless transmission path of a signal transmitted from a base station to a terminal, and an uplink (UL) may refer to a wireless transmission path of a signal transmitted from a terminal to a base station. In addition, although the embodiments of the present disclosure are described below using LTE or LTE-A systems as examples, the embodiments of the present disclosure may be applied to other communication systems having similar technical backgrounds or channel types. For example, the fifth generation mobile communication technology (5G, new radio, NR) developed after LTE-A may be included here. 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 judged by a person having skilled technical knowledge.

As a representative example of the above-described broadband wireless communication system, the NR system adopts the Orthogonal Frequency Division Multiplexing (OFDM) method in the downlink (DL), and adopts both OFDM and SC-FDMA (Single Carrier Frequency Division Multiple Access) methods in the uplink (UL). The uplink can mean a wireless link in which a terminal (or User Equipment, UE) or a mobile station ((MS)) transmits data or a control signal to a base station (eNode B or base station (BS)), and the downlink can mean a wireless link in which a base station transmits data or a control signal to a terminal. In the multiple access method as described above, the time-frequency resources for transmitting data or control information to each user are allocated and operated so as not to overlap with each other, that is, so as to achieve orthogonality, so that the data or control information of each user can be distinguished.

The NR system can adopt the HARQ (Hybrid Automatic Repeat reQuest) method to retransmit the corresponding data in the physical layer if a decoding failure occurs in the initial transmission. The HARQ method means that if the receiver fails to correctly decode the data, the receiver transmits information (NACK; Negative Acknowledgement) to the transmitter to notify the decoding failure so that the transmitter can retransmit the corresponding data in the physical layer. The receiver can combine the data retransmitted by the transmitter with the data that previously failed to be decoded to improve the data reception performance. In addition, if the receiver correctly decodes the data, it can transmit information (ACK; Acknowledgement) to the transmitter to notify the transmitter of the decoding success so that the transmitter can transmit new data.

FIG. 1 is a diagram illustrating an uplink and downlink time-frequency domain transmission structure of an NR or 5G communication system according to one embodiment of the present disclosure. More specifically, FIG. 1 is a diagram for explaining the basic structure of a time-frequency domain, which is a radio resource region in which the above-described data or control channel is transmitted in the 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 or DFT-s-OFDM symbol, and N _symb (101) OFDM or DFT-s-OFDM symbols can be gathered to form one slot (102). Here, the OFDM symbol may mean a symbol for transmitting and receiving a signal using an OFDM multiplexing method, and the DFT-s-OFDM symbol may mean a symbol for transmitting and receiving a signal using a DFT-s-OFDM or SC-FDMA multiplexing method. In the following disclosure, for the convenience of explanation, OFDM and DFT-s-OFDM symbols will be described interchangeably as OFDM symbols without distinction, and the description will be based on downlink signal transmission and reception. However, it will be sufficiently understood by those skilled in the art that the present disclosure can also be applied to uplink signal transmission and reception.

When the spacing between subcarriers is 15 kHz, one slot can be gathered to form one subframe (103), and the lengths of the above-described slots and subframes can each be 1 ms. At this time, the number of slots forming one subframe (103) and the length of the slots can vary depending on the spacing between subcarriers. For example, when the spacing between subcarriers is 30 kHz, four slots can be gathered to form one subframe (103). At this time, the length of the slot can be 0.5 ms and the length of the subframe can be 1 ms.

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

In the time-frequency domain, the basic unit of resources is a resource element (106, Resource Element; RE), which can be represented by an OFDM symbol index and a subcarrier index. A resource block (107, Resource Block; RB or Physical Resource Block; PRB) can 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 can contain REs. Typically, the minimum allocation unit of data in the frequency domain can be RB (107). In the NR system, typically N _symb = 14, N _SC ^RB = 12, and the number of RBs (N _RB ) can vary depending on the bandwidth of the system transmission band. In the LTE system, typically N _symb = 7, N _SC ^RB = 12, and N _RB can vary depending on the bandwidth of the system transmission band.

Downlink control information can be transmitted within the first N OFDM symbols in the above-described subframe. Typically, N can be {1, 2, 3}, and the terminal can be configured with the number of symbols in which the downlink control information can be transmitted from the base station through an upper signal. In addition, depending on the amount of control information to be transmitted in the current slot, the base station can vary the number of symbols in which the downlink control information can be transmitted in the slot for each slot, and can transmit information about the number of the above-described symbols to the terminal through a separate downlink control channel.

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

- Control information identifier (DCI format identifier): An identifier that identifies the format of the received DCI.

- Frequency domain resource assignment: Indicates the RBs allocated for data transmission.

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

- VRB-to-PRB mapping: Indicates whether to apply VRB mapping method.

- Modulation and coding scheme (MCS): Indicates 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 this is a HARQ initial transmission or a retransmission.

- Redundancy version: Indicates the redundancy version of HARQ.

- HARQ process number: Indicates the HARQ process number.

- PDSCH allocation information (Downlink assignment index): Indicates the number of PDSCH reception results that the terminal must report to the base station (e.g., the number of HARQ-ACKs).

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

- PUCCH resource indicator: PUCCH resource indicator used for HARQ-ACK reporting that includes the reception result for the PDSCH set through the corresponding DCI.

- PUCCH transmission timing indicator (PDSCH-to-HARQ_feedback timing indicator): Indicates the slot or symbol information in which the PUCCH for HARQ-ACK reporting containing the reception result for the PDSCH set through the corresponding DCI should be transmitted.

The DCI described above can be transmitted on a downlink physical control channel, PDCCH (Physical downlink control channel) (or control information, hereinafter used interchangeably) or EPDCCH (Enhanced PDCCH) (or enhanced control information, hereinafter used interchangeably) through channel coding and modulation processes.

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

Downlink data can be transmitted on the Physical Downlink Shared Channel (PDSCH), which is a physical channel for downlink data transmission. The PDSCH can be transmitted after the control channel transmission section described above, and scheduling information such as specific mapping positions and modulation methods in the frequency domain can be determined based on the DCI transmitted through the PDCCH.

Among the control information constituting the DCI described above, through MCS, the base station can 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 can be composed of 5 bits or more or less bits. The TBS can correspond to the size of the data (transport block, TB) to be transmitted by the base station before channel coding for error correction is applied.

The modulation methods supported in the NR system can include Quadrature Phase Shift Keying (QPSK), Quadrature Amplitude Modulation (16QAM), 64QAM, and 256QAM, and the modulation orders (Qm) are 2, 4, and 6, respectively. That is, in the case of QPSK modulation, 2 bits per symbol can be transmitted, 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, modulation methods higher than 256QAM can also be used depending on system variation.

In the NR system, uplink/downlink HARQ adopts an asynchronous HARQ scheme in which data retransmission time is not fixed. For example, in the downlink, if a base station receives HARQ NACK feedback from a terminal for initially transmitted data, the base station can freely determine the transmission time of the retransmission data by a scheduling operation. The terminal decodes the received data for the HARQ operation, buffers the data determined to be an error as a result, and then combines it with the data retransmitted from the base station. HARQ ACK/NACK information of a PDSCH transmitted in subframe n-k can be transmitted from the terminal to the base station through a PUCCH or PUSCH in subframe n. In a 5G communication system such as NR, the above-mentioned k value can be included in and transmitted in the DCI instructing or scheduling reception of the PDSCH transmitted in subframe n-k, or the k value can be set to the terminal through a higher layer signal. At this time, the base station may set one or more k values as upper signals and may also indicate a specific k value through DCI. At this time, 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 PDSCH. In addition, the terminal may use a predefined value or a default value until the k value is set.

Hereinafter, in order to explain the wireless communication system described above and the method and device proposed in the embodiment of the present disclosure, the NR system is used as a reference; however, the contents of the present disclosure are not limited to the NR system and can be applied to various wireless communication systems such as LTE, LTE-A, LTE-A-Pro, and 5G. In addition, although the present disclosure has been described based on a system and device that transmits and receives a signal using an unlicensed band, the contents of the present disclosure can also be applied to a system operating in a licensed band.

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

In a system performing communication in an unlicensed band, a transmitting device (base station or terminal) that wishes to transmit a signal through the unlicensed band may perform a channel access procedure (or LBT: listen-before talk) for the unlicensed band on which communication is to be performed before transmitting the above-described signal. If the transmitting device determines 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 the unlicensed band is determined not to be idle according to the performed channel access procedure, the transmitting device may not perform signal transmission.

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

For example, the transmitting device measures the signal strength for Xus (e.g., 25us) immediately prior to the time at which it is to transmit the signal, and if the measured signal strength is less than a predefined or calculated threshold value T (e.g., -72dBm), it determines that the unlicensed band described above is idle, and can transmit the set signal. At this time, after the channel access procedure, the maximum time for which continuous signal transmission is possible may be limited by the maximum channel occupancy time defined for each unlicensed band by country, region, and frequency band, and may also be limited by the type of the transmitting device (e.g., a base station or terminal, or a master device or a slave device). For example, in the case of Japan, a base station or terminal in the 5GHz unlicensed band can transmit a signal by occupying the above-mentioned channel for up to 4ms without performing an additional channel access procedure for an unlicensed band determined to be idle after performing the channel access procedure.

More specifically, when a base station or a terminal wishes to transmit a downlink or uplink signal in an unlicensed band, the channel access procedures that the base station or terminal can perform can be explained by dividing them into at least the following types.

- Type 1: Transmitting uplink/downlink signals after performing channel access procedure for variable time

- Type 2: Transmits uplink/downlink signals after performing channel access procedure for a fixed time

- Type 3: Transmitting downlink or uplink signals without performing channel access procedures

Hereinafter, the present disclosure will be described interchangeably with the case where a base station transmits a downlink signal to a terminal through an unlicensed band and the case where a terminal transmits an uplink signal to a base station through an unlicensed band. However, the contents proposed in the present disclosure can be equally applied or applied with some modifications to the case where a terminal transmits an uplink signal to a base station through an unlicensed band or the case where a base station transmits a downlink signal to a terminal through an unlicensed band. Therefore, a detailed description of the downlink signal transmission and reception is omitted. In addition, the present disclosure will be described assuming the case where one downlink data information (codeword or TB) or uplink data information is transmitted and received between the base station and the terminal. However, the contents proposed in the present disclosure can also be applied to the case where a base station transmits a downlink signal to multiple terminals, or the case where multiple 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 wishes to transmit a signal in an unlicensed band can determine a channel access procedure method according to the type of signal to be transmitted. For example, if the base station wishes to transmit a downlink signal including a downlink data channel in an unlicensed band, the base station can perform a channel access procedure of the Type 1 method. In addition, if the base station wishes to transmit a downlink signal not including a downlink data channel in an unlicensed band, for example, if it wishes to transmit a synchronization signal or a downlink control channel, the base station can perform a channel access procedure of the Type 2 method and transmit the above-described downlink signal.

At this time, 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 or the length of the section to be used by occupying the above-mentioned unlicensed band. In general, the Type 1 method may need to perform the channel access procedure for a longer time than the Type 2 method. Therefore, the base station may perform the channel access procedure of the Type 2 method when it wants to transmit a signal for a short time section or a time shorter than a reference time (e.g., X ms or Y symbols). On the other hand, the base station may perform the channel access procedure of the Type 1 method when it wants to transmit a signal for a long time section or a time exceeding or longer than the reference time (e.g., X ms or Y symbols). In other words, the base station may perform different channel access procedures depending on the unlicensed band usage time.

If a Type 1 channel access procedure is performed according to at least one of the above-described criteria, the base station may determine a channel access priority class according to the QCI (Quality of service Class Identifier) of a signal to be transmitted in the above-described unlicensed band, and perform the channel access procedure using at least one value from among the predefined setting values as shown in Table 1 for the determined channel access priority class. For example, QCI 1, 2, and 4 may represent 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 of Table 1 is to be transmitted in the unlicensed band, the base station may select a QCI that is closest to the above-described service and the QCI of Table 1, and select a channel access priority class for it.

Table 1 shows the mapping relationship between Channel Access Priority Classes and QCI.

[Table 1]

For example, referring to Table 2 described below, the base station can determine the defer duration according to the determined channel access priority (p), the set of values or sizes of the contention window (CW_p), the minimum and maximum values of the contention window (CW_min,p, CW_max,p), the maximum channel occupancy possible period (T_mcot,p), etc. through Table 2. In other words, the base station that wants to transmit a downlink signal in an unlicensed band can perform the channel access procedure for the unlicensed band for at least T_f + m_p*T_sl time.

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

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

[Table 2]

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

The value of the contention period (CW_p) may be changed based on the reception result of the downlink data channel in the reference subframe or reference slot among the downlink signal transmission periods (or MCOT) most recently transmitted by the base station through the unlicensed band at the time when the base station initiates the channel access procedure, or at the time when the base station selects the value of N to perform the channel access procedure, or immediately before that. In other words, the base station receives a report of the reception result of the terminal for the downlink data transmitted in the reference subframe or reference slot, and may increase or minimize the size of CW_p based on the ratio (Z) of NACKs among the reported reception results.

Referring to FIG. 2, for example, a contention period change criterion slot for a channel access procedure (270) may be the first transmission section (240) (hereinafter, slot or subframe) of a downlink signal transmission section (230) most recently transmitted through an unlicensed band at the time point (270) when the base station initiates the channel access procedure, or at the time point when the base station selects the N value to perform the channel access procedure, or immediately before that.

If the base station cannot receive a report of the reception result for the downlink data channel transmitted in the first slot (240) of the transmission section (230), the first subframe of the most recent downlink signal transmission section transmitted before the downlink signal transmission section (230) may become the reference subframe. For example, if 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 or equal to n slots or subframes, in other words, if the base station initiates the channel access procedure before the time at which the terminal can report the downlink data channel reception result for the first subframe (240). In other words, if the base station does not receive a reception result for the downlink data transmitted in the reference subframe (240) from the terminal at or immediately before the time point (270) at which the base station initiates the channel access procedure or the time point at which the base station selects the N value to perform the channel access procedure, the base station may determine the first subframe of the most recently transmitted downlink signal transmission section among the reception results for the downlink data channel previously received from the terminals as the reference subframe. In addition, the base station can determine the contention interval size used in the channel access procedure (270) by using the downlink data reception results received from terminals for downlink data transmitted through the downlink data channel in the reference subframe.

For example, the base station can transmit a downlink signal through a channel access procedure (e.g., CW_p=15) set by channel access priority type 3 (p=3). At this time, if 80% or more of the reception results of the terminal for the downlink data transmitted to the terminal through the downlink data channel in the first subframe among the downlink signals transmitted through the unlicensed band are determined to be NACK, the base station can increase the contention period from the initial value (CW_p=15) to the next contention period value (CW_p=31).

If 80% or more of the reception results of the terminal are not determined as NACK, the base station can maintain the value of the contention period as the existing value or change it to the initial value of the contention period. At this time, the change of the contention period can be applied commonly to all types of channel access priorities, or can be applied only to the type of channel access priority used in the channel access procedure. At this time, in the reference subframe or reference slot for determining the change in the contention period size, among the reception results for downlink data transmitted or reported by the terminal to the base station through the downlink data channel, a method for determining a valid reception result for determining the change in the contention period size, in other words, a method for determining the Z value, can be as follows.

If the base station transmits one or more codewords or TBs to one or more terminals in a reference subframe or reference slot, the base station can determine the Z value as the ratio of NACKs among the reception results transmitted or reported by the terminals for the TBs received in the reference subframe or reference slot. For example, if two codewords or two TBs are transmitted to one terminal in the reference subframe or reference slot, the base station can transmit or receive the downlink data signal reception results for the two TBs from the terminal. If the ratio (Z) of NACKs among the two reception results is equal to or greater than a threshold value (for example, Z=80%) defined in advance or set between the base station and the terminal, the base station can change or increase the contention period size described above.

When a terminal bundles and transmits or reports to a base station the downlink data reception results for one or more subframes (e.g., M subframes) including the above-described reference subframe or slot, the base station may determine that the terminal has transmitted M reception results. In addition, the base station may determine the Z value based on the ratio of NACKs among the above-described M reception results, and change, maintain, or initialize the contention period size.

In addition, the base station can determine the Z value described above based on the ratio of NACKs among the reception results transmitted or reported by the terminal to the base station for downlink data received in the above-described reference subframe (i.e., the second slot) and the next subframe, when the reference subframe is a reception result for the second slot of two slots constituting one subframe.

In addition, if scheduling information or downlink control information for a downlink data channel transmitted by the 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 if scheduling information or downlink control information for a downlink data channel transmitted by the base station is transmitted through an unlicensed band but in a different cell or frequency than the cell in which the downlink data channel is transmitted, and if it is determined that the terminal has not transmitted the reception result for the downlink data received in the reference subframe or reference slot, or if the reception result for the downlink data transmitted by the terminal is determined as DTX, or NACK/DTX, or any state, the base station may determine the reception result of the terminal as NACK and determine the above-described Z value.

In addition, if scheduling information or downlink control information for a downlink data channel transmitted by a base station is transmitted through a licensed band, and if the reception result for the downlink data transmitted by the terminal is determined as DTX, or NACK/DTX, or any state, the base station may not include the reception result of the terminal in the reference value Z of the contention period variation. In other words, the base station may ignore the 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, if the base station does not actually transmit downlink data (no transmission) in the downlink data reception result for the reference subframe or reference slot transmitted or reported by the terminal to the base station, the base station may ignore the reception result transmitted or reported by the terminal for the downlink data and determine the Z value.

In the 5G system, it is necessary to flexibly define and operate the frame structure by considering various services and requirements. For example, each service can be considered to have a different subcarrier interval according to the requirement. In the current 5G communication system, a method to support multiple subcarrier intervals can be determined using the following [Mathematical Formula 1].

[Mathematical formula 1]

Here, f ₀ represents the basic subcarrier spacing of the system, and m can represent an integer scaling factor. For example, if f ₀ is 15 kHz, the set of subcarrier spacings that the 5G communication system can have may be composed of 3.75 kHz, 7.5 kHz, 15 kHz, 30 kHz, 60 kHz, 120 kHz, 240 kHz, 480 kHz, etc. In one embodiment of the present disclosure, the set of available subcarrier spacings may be different depending on the frequency band. For example, 3.75 kHz, 7.5 kHz, 15 kHz, 30 kHz, 60 kHz can be used in a frequency band below 6 GHz, and 60 kHz, 120 kHz, 240 kHz can be used in a frequency band above 6 GHz.

The length of an OFDM symbol can vary depending on the subcarrier spacing that constitutes the OFDM symbol. This is because the subcarrier spacing and the length of an OFDM symbol have an inverse relationship, which is a characteristic of an OFDM symbol. For example, if the subcarrier spacing doubles, the symbol length can be shortened by half, and conversely, if the subcarrier spacing decreases by half, the symbol length can be twice as long.

Next, we describe the resource area in which data channels are transmitted in a 5G communication system.

FIG. 3 is a diagram illustrating a resource region in which a data channel is transmitted in an NR or 5G communication system according to one embodiment of the present disclosure.

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

Here is an example of a case where a terminal is scheduled to transmit an uplink data channel (PUSCH). The terminal, which has received DCI, can obtain a slot index or offset information (K) at which a PUSCH should be received through the DCI, and determine a PUSCH transmission slot index. Referring to FIG. 3, for example, the terminal can determine that the terminal is scheduled to transmit a PUSCH in slot i+K (305) through the received offset information (K), based on the slot index i (300) in which the PDCCH (310) is received. At this time, the terminal can also determine the slot i+K (305) or the PUSCH start symbol or time in slot i+K through the received offset information (K), based on the CORESET in which the PDCCH (310) is received. In addition, the terminal can obtain information about a PUSCH transmission time-frequency resource region (340) in a PUSCH transmission slot (305) through the DCI. At this time, PUSCH transmission frequency resource area information (330) may be PRB or PRB group unit information.

Meanwhile, the PUSCH transmission frequency resource region information (330) may be a region included in the initial uplink bandwidth (initial BW, BandWidth) or the initial uplink bandwidth part (initial BWP, BandWidth Part) determined or set by the terminal through the initial access procedure. If the terminal has the uplink bandwidth (BW, BandWidth) or the uplink bandwidth part (BWP, BandWidth Part) set through a higher signal, the PUSCH transmission frequency resource region information (330) may be a region included in the uplink bandwidth (BW, BandWidth) or the uplink bandwidth part (BWP, BandWidth Part) set through a higher signal.

The PUSCH transmission time resource region information (325) may be symbol or group unit information of symbols, or information indicating absolute time information. At this time, the PUSCH transmission time resource region information (325) may be expressed as a combination of a PUSCH transmission start time or symbol and a PUSCH length or a PUSCH end time or symbol, and may be included in the DCI as a single field or value. At this time, the PUSCH transmission time resource region information (325) may be included in the DCI as a field or value expressing each of a PUSCH transmission start time or symbol and a PUSCH length or a PUSCH end time or symbol. The terminal may transmit the PUSCH in the PUSCH transmission resource region (340) determined through the DCI.

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

FIG. 4 is a diagram illustrating 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 according to one embodiment of the present disclosure. Referring to FIG. 4, two control regions (Control Region #1 (401), Control Region #2 (402)) are set within a bandwidth portion (410) of a terminal in the frequency axis and within 1 slot (420) in the time axis.

Control areas (401, 402) can be set to specific frequency resources (403) within the entire terminal bandwidth portion (410) along the frequency axis. One or more OFDM symbols can be set along the time axis, and this can be defined as a control area length (Control Resource Set Duration, 404). In Fig. 4, for example, control area #1 (401) is set to a control area length of 2 symbols, and control area #2 (402) is set to a control area length of 1 symbol.

The control region in 5G can be set through upper layer signaling (e.g., System Information, MIB (Master Information Block), RRC (Radio Resource Control) signaling) that the base station provides to the terminal. Setting the control region to the terminal may mean providing information such as a control region identifier (Identity), frequency location of the control region, and symbol length of the control region. For example, the control region setting may include the following information.

[Table 3]

로 가지는 6 PRB 그룹을 의미하며, 여기서

는 BWP 시작지점을 나타낼 수 있다. 비트맵의 최상위 비트는 첫번째 그룹을 지시하며 오름차순으로 설정될 수 있다.In the above-described Table 3, the tci-StatesPDCCH (hereinafter referred to as TCI state) configuration information may include information on one or more SS (Synchronization Signal)/PBCH (Physical Broadcast Channel) block indices or CSI-RS (Channel State Information Reference Signal) indices that are related to the DMRS and QCL (Quasi Co Location) transmitted in the corresponding control region. In addition, the frequencyDomainResources configuration information may set the frequency resources of the corresponding CORESET as a bitmap. Here, each bit may indicate a group of 6 non-overlapping PRBs. The first group may indicate the first PRB index.

It refers to the 6 PRB groups, where

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

FIG. 5 is a diagram illustrating a structure of a downlink control channel that can be used in an NR or 5G communication system according to one embodiment of the present disclosure. Specifically, FIG. 5 is a diagram showing 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 FIG. 5, a basic unit of time and frequency resources constituting a control channel can be called a REG (Resource Element Group, 503), and a REG (503) can be defined as 1 OFDM symbol (501) in the time axis and 1 PRB (Physical Resource Block, 502) in the frequency axis, that is, 12 subcarriers. The REGs (503) can be concatenated to configure a downlink control channel allocation unit.

As illustrated in FIG. 5, when the basic unit to which a downlink control channel is allocated in 5G is called a CCE (Control Channel Element, 504), 1 CCE (504) can be composed of multiple REGs (503). Taking the REG (503) illustrated in FIG. 4 as an example, the REG (503) can 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 region can be composed of multiple CCEs (504), and a specific downlink control channel can be mapped to one or multiple CCEs (504) and transmitted according to the aggregation level (AL) in the control region. The CCEs (504) in the control region are distinguished by numbers, and the numbers can be assigned according to a logical mapping method.

The basic unit of the downlink control channel illustrated in Fig. 5, i.e., REG (503), may include both REs to which DCI is mapped and areas to which a DMRS (Demodulation Reference Signal, 505), which is a reference signal for decoding the REs, is mapped. As an example, as in Fig. 5, three DMRSs (505) may be transmitted within one REG (503).

The number of CCEs required to transmit a PDCCH can be 1, 2, 4, 8, or 16 depending on the aggregation level (AL), and different numbers of CCEs can be used to implement link adaptation of a downlink control channel. For example, when AL=L, one downlink control channel can be transmitted through L CCEs. A terminal must detect a signal without knowing information about the downlink control channel, and a search space representing a set of CCEs can be used to assist such blind decoding. The search space is a set of downlink control channel candidates consisting of CCEs that the terminal should attempt to decode at a given aggregation level. According to one embodiment of the present disclosure, since there are various aggregation levels that form one bundle with 1, 2, 4, 8, or 16 CCEs, the terminal can have multiple search spaces. A search space set can be defined as a collection of search spaces at all established aggregation levels.

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

In 5G, parameters for a PDCCH search space can be configured from a base station to a terminal based on higher layer signaling (e.g., SIB, MIB, RRC signaling). For example, the base station can configure the number of PDCCH candidates in each aggregation level L, a monitoring period for the search space, a monitoring occasion for each symbol in a slot for the search space, a search space type (common search space or terminal-specific search space), a combination of DCI formats and RNTIs to be monitored in the corresponding search space, a control region index to be monitored for the search space, etc. to the terminal. For example, the above-described configuration information may include the following information.

[Table 4]

Depending on the configuration information, the base station can set one or more search space sets for the terminal. For example, the base station can set search space set 1 and search space set 2 for the terminal, and can set the terminal to monitor DCI format A scrambled with X-RNTI in search space set 1 in a common search space, and can set the terminal to monitor DCI format B scrambled with Y-RNTI in search space set 2 in a terminal-specific search space.

According to the above-described configuration information, one or more 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 terminal-specific search spaces.

In the common search space, the following combinations of DCI formats 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 a terminal-specific search space, the following combinations of DCI formats and RNTI can 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 terminal-specific PDSCH scheduling purposes.

- TC-RNTI (Temporary Cell RNTI): For terminal-specific PDSCH scheduling purposes.

- CS-RNTI (Configured Scheduling RNTI): For terminal-specific PDSCH scheduling purposes that are set semi-statically.

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

- P-RNTI (Paging RNTI): Used for scheduling PDSCH where paging is transmitted.

- SI-RNTI (System Information RNTI): Used for scheduling PDSCH where system information is transmitted.

- INT-RNTI (Interruption RNTI): Used to indicate whether pucturing is in progress for PDSCH.

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

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

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

In 5G, multiple search space sets can be configured with different parameters (e.g., DCI format). Therefore, the set of search space sets monitored by the terminal at each point in time can be different. For example, if search space set #1 is configured with an X-slot period and search space set #2 is configured with a Y-slot period, and when X and Y are different, the terminal can monitor both search space set #1 and search space set #2 in a specific slot, or monitor either search space set #1 or search space set #2 in a specific slot.

When multiple search space sets are set for a terminal, the following conditions may be considered in determining the search space set that the terminal should monitor.

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

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

[Table 5]

[Condition 2: Maximum CCE number limit]

The number of CCEs composing 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 area of multiple search space sets. C ^μ may be defined as the maximum number of CCEs per slot in a cell set to a subcarrier spacing of 15·2 ^μ kHz, and may be defined as shown in the table below.

[Table 6]

For the convenience of description, let us define “Condition A” as a situation in which both conditions 1 and 2 described above are satisfied at a certain point in time. Therefore, not satisfying Condition A may mean not satisfying at least one of conditions 1 and 2 described above.

Depending on the configuration of the search space sets of the base station, the condition A described above may not be satisfied at a certain point in time. If the condition A described above is not satisfied at a certain point in time, the terminal may select and monitor only some of the search space sets configured to satisfy condition A at that point in time, and the base station may transmit a PDCCH to the selected search space set.

The following method can be used to select a portion of the search space from the entire set of search spaces.

[Method 1]

If condition A for a PDCCH is not satisfied at a specific point in time (or slot), the terminal (or base station) may preferentially select a search space set whose search space type is set to a common search space among the search space sets existing at that point in time over a search space set that is set to a terminal-specific search space.

If all search space sets set as common search spaces are selected (i.e., if condition A is satisfied even after all search spaces set as common search spaces are selected), the terminal (or base station) can select search space sets set as terminal-specific search spaces. At this time, if there are multiple search space sets set as terminal-specific search spaces, a search space set with a lower search space set index may have a higher priority. The terminal or base station can select terminal-specific search space sets within the range that satisfies condition A, taking the priority into consideration.

For NR or 5G communication systems, terminals can transmit uplink signals without uplink scheduling information to provide various services and support high data transmission rates. More specifically, When a terminal wants to transmit an uplink signal without uplink scheduling information, information such as resource allocation and MCS for uplink transmission can be set through RRC signaling or DCI of PDCCH, and the uplink transmission that can be performed is Depending on the method of receiving the uplink transmission settings, it can be described by dividing them into at least the following types.

- Type 1: Uplink transmission setup using RRC signaling

- Type 2: Uplink transmission setup using the uplink data channel of the physical layer

FIG. 6 is a diagram illustrating an example of transmitting an uplink signal without uplink scheduling information in an unlicensed band according to one embodiment of the present disclosure.

In an unlicensed band, a terminal may perform a channel access procedure to transmit an uplink signal without uplink scheduling information. At this time, when the terminal performs the channel access procedure for a variable time to access the unlicensed band, the terminal may schedule the last slot (604) or the last subframe (604) within the maximum channel occupancy time (612) as downlink transmission through a channel occupancy time sharing indicator of uplink control information (605). At this time, the base station may determine channel access by performing the channel access procedure for a fixed time, and the terminal may set the last symbol of the slot (608) or subframe (608) for uplink transmission as a gap interval left empty for the channel access procedure of the base station.

Referring to FIG. 6, downlink transmission may be limited to PDCCH (609), and the start symbol of PDCCH (609) may be limited to the first symbol of the last slot (604) or the last subframe (604), and may have a symbol length of no more than two. Meanwhile, since downlink transmission time resource region information in a 5G communication system may be determined through DCI, the transmission start time or symbol of PDCCH (610) and the length and end time or symbol of PDSCH (611) may be set in various ways. Therefore, when sharing the maximum channel occupancy time acquired by the terminal, it is necessary to indicate time resource region information for downlink reception in the uplink control information (620).

In a 5G communication system, in order to dynamically change the downlink signal transmission and uplink signal transmission intervals in a TDD system, each of the OFDM symbols constituting a slot can be indicated as a downlink symbol, an uplink symbol, or a flexible symbol through a slot format indicator (SFI). Here, a symbol indicated as a flexible symbol means a symbol that is not both a downlink and an uplink symbol, or a symbol that can be changed into a downlink or uplink symbol by terminal-specific control information or scheduling information. In this case, the flexible symbol may include a gap interval (Gap guard) required in the process of switching from downlink to uplink.

The slot format indicator is transmitted to multiple terminals simultaneously through a terminal group (or cell) common control channel. In other words, the slot format indicator is transmitted through a PDCCH that is CRC-scrambled with a terminal unique identifier (C-RNTI) and another identifier (e.g., SFI-RNTI). At this time, the slot format indicator can include information on N slots. The value of N is an integer greater than 0 or a natural number, or can be set by the base station to the terminal through an upper layer signal from among a set of predefined possible values such as 1, 2, 5, 10, and 20. In addition, the size of the slot format indicator information can be set by the base station to the terminal through an upper layer signal. Examples of slot formats that the slot format indicator can indicate are as shown in [Table 7] below.

[Table 7] Example of slot format structure information

In [Table 7], D represents downlink, U represents uplink, and X represents a flexible symbol. The total number of formats that can be supported in [Table 7] is 256. In the current NR system, the maximum size of the slot format indicator information bit is 128 bits, and the slot format indicator information bit is a value that the base station can set to the terminal through a higher signal (e.g., dci - PayloadSize ). The slot format indicator information may include slot formats for multiple serving cells, and the slot formats for the serving cells may be distinguished through the servingcell ID. In addition, a combination of slot format indicators for one or more slots for each of the serving cells (Slot format combination) may be included in the slot format indicator information. For example, if the size of the slot format indicator information bit is 3 bits and the slot format indicator information is configured as a slot format indicator for one serving cell, the 3-bit slot format indicator information can be configured with a total of 8 slot format indicators or slot format indicator combinations (hereinafter, referred to as slot format indicators). The base station can indicate one slot format indicator among the 8 slot format indicators to the terminal through terminal group common control information (group common DCI) (hereinafter, referred to as slot format indicator information). At this time, at least one slot format indicator among the 8 slot format indicators can be configured as a slot format indicator for a plurality of slots. For example, in [Table 8] below, 5 pieces of information (slot format combination ID 0, 1, 2, 3, 4) of [Table 7] are slot format indicators for one slot, and the remaining 3 pieces of information are slot format indicators for 4 slots (slot format combination ID 5, 6, 7), which are sequentially applied to the 4 slots.

[Table 8] This is an example of slot format indicator information.

Meanwhile, if the terminal does not detect or receive a slot format DCI (e.g. , DCI format 2_0 ) indicating symbols in a slot that is flexibly indicated by upper signaling (e.g., tdd -UL- DL - ConfigurationCommon or tdd -UL-DL-ConfiguredDedicated ) or in which the slot format is not set by upper signaling (e.g., tdd -UL- DL - ConfigurationCommon or tdd -UL- DL - ConfiguredDedicated), the terminal may perform the following actions on the corresponding symbol.

- If the terminal receives DCI (e.g., DCI format 1_0, DCI format 1_1, DCI format 0_1) indicating PDSCH or CSI-RS reception in the corresponding symbol, the terminal can receive PDSCH or CSI-RS in the corresponding symbol.

- If the terminal receives DCI (e.g., DCI format 0_0, DCI format 0_1, DCI format 1_0, DCI format 1_1, DCI format 2_3) indicating transmission of PUSCH, PUCCH, PRACH, SRS in the corresponding symbol, the terminal can transmit PUSCH, PUCCH, PRACH, SRS in the corresponding symbol.

- If the terminal is set to receive PDSCH or CSI-RS in the corresponding symbol through upper signaling, the terminal does not receive PDSCH or CSI-RS in the corresponding symbol.

- If the terminal receives SRS or PUCCH or PUSCH or PRACH transmission as upper signaling in the corresponding symbol, and the start of transmission of the corresponding uplink transmission signal is located after the PUSCH preparation time from the last symbol of the CORESET for monitoring the format DCI, the terminal does not transmit the corresponding uplink signal.

- If the terminal is set to transmit SRS or PUCCH or PUSCH or PRACH in the corresponding symbol through upper signaling, and the start of transmission of the corresponding uplink transmission signal is located before the PUSCH preparation time from the last symbol of the CORESET for monitoring the slot format DCI, the terminal can transmit the corresponding uplink signal.

In a 5G communication system, a base station or a terminal can transmit and receive signals in a wideband unlicensed band, and the wideband unlicensed band can be configured in units of subbands (e.g., 20 MHz). The base station and the terminal can perform a channel access procedure in units of subbands to occupy the unlicensed band, and depending on the result of performing the channel access procedure, can access the unlicensed band in at least one of all idle subbands, one subband, or consecutive subbands to perform the configured signal transmission. At this time, the uplink signal can be transmitted as separate transmission data for each idle subband or as one transmission data in multiple idle subbands. Meanwhile, when the terminal performs a channel access procedure for each subband in the wideband unlicensed band and transmits an uplink signal in the idle subband, the base station cannot know which subband the terminal occupied to perform the uplink transmission. Therefore, the base station must demodulate the transmitted uplink signal by considering possible uplink transmission combinations in the scheduled subband. Therefore, in order to reduce the signal processing complexity of the base station, it is necessary for the terminal to inform the base station of the result of performing the channel access procedure or the resource area information used for uplink transmission.

In the present disclosure, a method is proposed in which a base station and a terminal configured to receive or transmit a downlink signal or an uplink signal in a wideband unlicensed band provide a terminal to the base station with information on the result of performing a channel access procedure for uplink transmission and information on a resource region used for uplink transmission. More specifically, a method and device are proposed in which a base station provides information on a resource region to be used by a terminal as downlink control information or in which a terminal includes uplink transmission information in uplink control information and transmits it.

The method and device proposed in the embodiments of the present disclosure below are not limited to each embodiment, and can be utilized in a method and device for setting or determining an uplink transmission region by using a combination of all or part of the embodiments proposed in the disclosure. In addition, the embodiment of the present disclosure will explain a case where a base station and a terminal set or determine an uplink transmission region in a subband-based wideband unlicensed band, but it can also be applied to a case where an uplink transmission region is set in a wideband system such as a multi-carrier or carrier aggregation transmission. In addition, it can also be applied to a case where a control channel region is set in a single carrier or single band system other than a wideband. In addition, the embodiment of the present disclosure will explain assuming a base station and a terminal operating in a wideband unlicensed band, but the method and device proposed in the embodiment of the present disclosure can be applied to a base station and a terminal operating in a licensed band or a shared spectrum as well as an unlicensed band. In addition, although the embodiments of the present disclosure will be described assuming scheduling-based wideband uplink transmission, it can also be applied to uplink transmission that does not require scheduling (configured grant).

[Example 1]

In this embodiment, a method is proposed for setting uplink signal transmission in a guard band when a terminal performs uplink transmission in a wideband unlicensed band. More specifically, a method and device are proposed for a terminal to instruct a base station about the use of a guard band through uplink control information when performing uplink transmission.

FIG. 7 is a diagram illustrating an example of setting uplink signal transmission in a guard band when a terminal performs uplink transmission in a wideband unlicensed band according to an embodiment of the present disclosure. With reference to FIG. 7, the operation of the present embodiment is described as follows.

In the following, the operation of a terminal is explained assuming that, in a base station and a terminal that transmit and receive signals in a wideband unlicensed band, a channel access procedure is performed based on a subband, and then the terminal is set to perform PUSCH transmission by accessing at least one or more idle subbands according to the result of performing the channel access procedure.

The terminal can perform the channel access procedure in subband units (701, 702, 703, 704). As a result of performing the channel access procedure, if subband #1 (702) and subband #2 (703) are determined to be idle subbands, the terminal can transmit uplink signals (706, 707) in subband #1 (702) and subband #2 (703). At this time, the uplink signals (706, 707) can be transmitted as separate transmission data for each idle subband or as one transmission data in multiple idle subbands.

Meanwhile, in the wideband unlicensed band, since the channel access procedure is performed on a subband basis, each subband must have a guard band (708, 709) where no signal is transmitted at both ends of the subband in order to protect the performance of the channel access procedure of the adjacent subband. To this end, the base station can perform uplink scheduling considering the guard band (708, 709). Alternatively, the base station can perform uplink scheduling without considering the guard band (708, 709). In this case, the terminal may not transmit an uplink signal in the guard band (708, 709) during uplink transmission.

However, if the terminal wants to perform uplink transmission in consecutive subbands (702, 703) as a result of performing a channel access procedure, there may be no need to protect the performance of the channel access procedure of the adjacent subband in the guard band (709) between the consecutive subbands. In other words, if the consecutive subbands (702, 703) are occupied, the terminal may be able to transmit an uplink signal even in the guard band (709) between the consecutive subbands. Hereinafter, a method for the terminal to set or determine signal transmission for the guard band between the consecutive subbands to the base station is proposed.

<Example 1-1>

Referring to FIG. 8, the operation of a terminal setting or determining signal transmission for a guard band between consecutive subbands to a base station is described as follows.

A terminal may transmit an uplink signal by including a guardband use indicator in uplink control information. More specifically, when the terminal intends to transmit an uplink signal (806, 807) in a plurality of consecutive subbands (802, 803) according to a result of performing a channel access procedure, the terminal may also transmit an uplink signal in a guardband (809) located between the consecutive subbands. At this time, the terminal includes a guardband use indicator in the uplink control information and transmits it to a base station, and the base station that receives it may decode the uplink signal by including the guardband (809) located between the consecutive subbands (802, 803). A method of configuring a guardband indicator in the uplink control information may be as follows.

[Method 1]

The terminal can indicate whether to use the guard band with 1-bit signaling. For example, if the guard band use indicator transmitted by the terminal in the uplink control information is 1, the base station can decode the uplink signal including the signal transmitted in the guard band. If the guard band use indicator transmitted by the terminal in the uplink control information is 0, the base station can determine that the uplink signal is not transmitted in the guard band and decode the uplink signal excluding the guard band.

[Method 2]

The terminal can indicate whether to use the guard band with X bit signaling. X can be set to the number of subbands set by upper signaling or the number of subbands scheduled by downlink control information or upper signaling from the base station. For example, the terminal can receive uplink scheduling for four subbands from the base station and perform uplink transmission only on subband #1 (802) and subband #2 (803) as a result of performing a channel access procedure for each subband. At this time, if the terminal wants to include an uplink signal in the guard band (809) between consecutive subbands (802, 803), the terminal can indicate whether to use the guard band with 4-bit bit information (for example, 0110) in the uplink control information. The base station that has received the bit information on whether to use the guard band can decode the uplink signal including the signal transmitted in the guard band (809) included between consecutive subbands.

When transmitting uplink control information including a guardband usage indicator, the terminal may transmit the uplink control information in each of all subbands (802, 803) on which uplink transmission is to be performed. At this time, each of the uplink control information may include at least information about each subband on which uplink transmission is to be performed (e.g., separate transmission data for each subband) or information about all subbands on which uplink transmission is to be performed (e.g., one transmission data in a plurality of idle bands). According to another embodiment of the present disclosure, when transmitting uplink, the terminal may include the uplink control information in only at least one specific subband and transmit it, and a method of selecting at least one specific subband may be as follows.

[Method 3]

According to one embodiment of the present disclosure, after performing a channel access procedure for each subband, the terminal may perform uplink transmission including uplink control information only in a subband having a lowest (or highest) subband index (or a set index) among at least one idle subband on which uplink transmission is to be performed. According to another embodiment of the present disclosure, the terminal may perform uplink transmission including uplink control information only in a subband on which CORESET#0 or SS/PBCH block transmission is set. According to another embodiment of the present disclosure, the terminal may transmit an uplink signal including uplink control information in a subband indicated by a base station through a higher layer signal or a control channel. In addition, the terminal may determine a subband to be transmitted including uplink control information by using one or more combinations of the above-described methods. In this case, if the base station succeeds in decoding uplink control information in one specific subband, it may not perform uplink control information decoding for other subbands.

[Method 4]

According to one embodiment of the present disclosure, after performing a channel access procedure for each subband, the terminal may set a specific subband to transmit uplink control information according to a specific rule among at least one idle subband on which uplink transmission is to be performed. For example, the terminal may determine a specific subband using at least a combination of a terminal number (UE ID), an RNTI value, a CRC, and the number of idle subbands (K). For example, the terminal may transmit an uplink signal including uplink control information in a subband of an index determined by mod(UE IDxRNTI, K).

The guardband usage indicator mentioned above may be used as information for indicating (or determining) to the base station not only whether the guardband is being used but also the results of performing the channel access procedure for each subband acquired by the terminal.

<Example 1-2>

According to one embodiment of the present disclosure, the terminal can determine whether to use the guardband when transmitting an uplink signal by receiving a guardband use indicator from a base station or by using scheduling information received from the base station. More specifically, when the base station transmits downlink control information to the terminal, it can transmit it including the guardband use indicator. At this time, the guardband use indicator can be included in the downlink control information by the bit signaling described above. According to another embodiment of the present disclosure, the terminal can determine whether to use the guardband by using at least a channel occupancy time (or frequency), a channel access procedure performing method (for example, Type 3), a start symbol position of uplink transmission, or a downlink channel sharing indicator among the scheduling information received from the base station. For example, if the time of receiving uplink scheduling from the base station is within the channel occupancy time (or frequency) of the base station, if an instruction to share a channel occupied by the base station is received, if the terminal receives an uplink signal from the base station without performing a channel access procedure (e.g., Type 3 channel access procedure), or if the time of starting uplink transmission is included in a gap period (e.g., 16 us) that does not require performing a channel access procedure, the terminal can determine that it can perform uplink transmission in a guard band within the consecutive subbands scheduled by the base station.

[Example 2]

In this embodiment, a method and device are proposed for a terminal to perform a channel access procedure for each subband in a wideband unlicensed band and to transmit the results of performing the channel access procedure for each subband to a base station.

FIG. 9 is a diagram illustrating an example in which a terminal performs a channel access procedure for each subband in a wideband unlicensed band according to one embodiment of the present disclosure and transmits the results of performing the channel access procedure for each subband to a base station. With reference to FIG. 9, the operation of the present embodiment is described as follows.

According to one embodiment of the present disclosure, a terminal may perform a channel access procedure for each subband in a wideband unlicensed band and may notify a base station of the results of performing the channel access procedure. More specifically, the terminal may include information about a subband that is determined to be an idle band and transmits an uplink signal in uplink control information through bit signaling and notify the base station of the results.

For example, the terminal may determine that subband #1 (902) and subband #2 (903) are idle bands as a result of performing a channel access procedure, and may perform uplink transmission in the subbands (902, 903) determined to be idle bands. At this time, the terminal may transmit bit signaling (e.g., 0110) to the base station by including it in the uplink control information. At this time, the uplink control information may be transmitted in a slot that is at least one slot later than the slot (905) in which the first uplink transmission is performed, or after a certain period of time.

As another example, the terminal may transmit the first uplink transmission including uplink control information (908) through puncturing or rate matching within the slot (905) in which the first uplink transmission is performed. Here, the puncturing or rate matching may be determined by considering at least the payload size or processing time of the uplink control information. For example, if the payload size is less than or equal to [X] bits or the processing time (or symbol) for generating the uplink signal after rate matching is less than or equal to [Y], the terminal may perform puncturing to include the uplink control information in the uplink signal.

The result of the channel access procedure instructed by the above-described terminal to the base station may also be used as information for determining (or instructing) the use of guard bands between consecutive subbands of the base station or terminal.

[Example 3]

In this embodiment, a method and device for setting (or determining) the location of uplink control information when a terminal performs a channel access procedure for each subband for uplink transmission in a wideband unlicensed band and wants to transmit an uplink signal based on the result of performing the channel access procedure are proposed.

<Example 3-1>

The operation of the terminal according to the present embodiment may be described as follows with reference to FIG. 9.

When the terminal wants to transmit an uplink signal by including the aforementioned guardband usage indicator in the uplink signal or without including the uplink signal in the guardband, the uplink control information (911, 912) may not be included in the guardband. For example, when the terminal wants to transmit an uplink signal in consecutive subbands (902, 903) as a result of performing a channel access procedure, the terminal may also transmit the uplink signal in the guardband (910) located between the consecutive subbands (902, 903). In this case, the terminal may not place the uplink control information (911, 912) indicating whether to use the guardband in the guardband (910).

<Example 3-2>

The terminal can transmit the result of the above-described terminal channel access procedure to the base station as separate uplink control information. At this time, the terminal can transmit the uplink control information by including it in the first uplink signal transmission through puncturing or rate matching within the slot in which the first uplink transmission is performed. The position of the uplink control information within the slot in which the first uplink transmission is performed can be determined in the following manner.

[Method 1]

The operation of the terminal according to the present embodiment may be described as follows with reference to FIG. 10.

According to one embodiment of the present disclosure, when multiple DMRS transmissions are set within one slot during uplink signal transmission, the terminal may transmit an uplink signal by including uplink control information (1013) in the first symbol capable of uplink signal transmission after the last DMRS (1004). At this time, the uplink control information may be mapped from the lowest (or highest) resource element, and may be mapped at a certain interval according to the number of bits to be mapped.

Additionally, the terminal can transmit an uplink signal including uplink control information (1023) starting from the first symbol or the first resource element where uplink data transmission starts after the first DMRS.

[Method 2]

According to one embodiment of the present disclosure, the base station can instruct the terminal to transmit a resource region in which separate uplink control information is to be transmitted using upper signaling or downlink control information. For example, if the base station instructs the terminal to transmit uplink control channel information in symbol #9, the terminal can map uplink control channel information from the lowest (or highest) resource element of symbol #9.

[Method 3]

According to one embodiment of the present disclosure, the terminal can send the mapping location of separate uplink control information by setting the time or frequency domain location to the existing uplink control information. The base station can first decode the existing uplink control information, and then obtain the mapping location of the separate uplink control information to perform decoding of the separate uplink control information.

[Method 4]

The operation of the terminal according to the present embodiment is described as follows with reference to FIG. 10.

According to one embodiment of the present disclosure, the terminal can puncture channel access procedure execution result information (1033) in an area (1032) where existing uplink control information is located. At this time, the terminal can make a judgment on puncturing performance according to the priority of information included in the existing uplink control information. For example, the terminal can transmit the channel access procedure execution result by puncturing a resource element having channel information or HARQ feedback information.

[Example 4]

In this embodiment, a method and device are proposed for changing (or adjusting) the position of uplink control information included when a terminal transmits an uplink signal when the terminal performs a channel access procedure for each subband in a wideband unlicensed band and transmits the result of the channel access procedure performed by the terminal to a base station.

More specifically, the terminal can perform a channel access procedure for each third band and report the result of performing the channel access procedure to the base station using the method described above. Thereafter, the terminal can change (or adjust) the mapping position of the uplink control information transmitted together with the uplink signal transmission at least one slot after the slot in which the result of performing the channel access procedure is transmitted or after a certain period of time. Hereinafter, a specific method for the terminal to change (or adjust) the position of the uplink control information is proposed.

<Example 4-1>

FIG. 11 is a diagram illustrating an example of a terminal changing (or adjusting) the location of uplink control information according to an embodiment of the present disclosure. With reference to FIG. 11, the operation of the terminal according to the embodiment may be described as follows.

According to one embodiment of the present disclosure, a terminal may transmit a guardband usage indicator to a base station, or may transmit a result of a channel access procedure of the terminal that instructs uplink signal transmission in consecutive subbands to the base station. At this time, the terminal may transmit uplink control information (1106) including the uplink control information in the guardband (1120) between consecutive subbands from at least the next slot (1104) or after a certain period of time starting from a slot (1103) in which an uplink signal including uplink control information is transmitted. At this time, the terminal may determine the number of bits of the uplink control information by considering the guardband (1120). In addition, a slot or a certain period of time to which a changed mapping position of the uplink control information is applied may be received from the base station as upper signaling or downlink control information.

<Example 4-2>

The operation of the terminal according to the present embodiment may be described as follows with reference to FIG. 11.

According to one embodiment of the present disclosure, before transmitting a result of performing a channel access procedure for each subband or a guardband usage indicator to a base station, the terminal may transmit uplink control information (1107, 1108) in multiple subbands. At this time, each uplink control information may include information about at least each subband (e.g., different transmission data for each subband) or information about the entire subband transmitting the uplink (e.g., one transmission data in multiple subbands).

Meanwhile, the terminal may transmit a guardband usage indicator to the base station, or transmit the result of the terminal's channel access procedure, which means uplink signal transmission in consecutive subbands, to the base station. At this time, the terminal may transmit uplink control information (1107, 1108) including information capable of indicating (or determining) the result of the terminal's channel access procedure to the base station, including uplink control information (1109), only in at least one specific subband, starting from the slot (1113) in which the corresponding uplink control information was transmitted, at least after the next slot (1114) or after a certain period of time. The method of selecting at least one specific subband may be as follows.

[Method 1]

According to one embodiment of the present disclosure, after performing a channel access procedure for each subband, the terminal may transmit uplink control information only in a subband having a lowest (or highest) subband index (or configuration index) among at least one idle subband on which uplink transmission is to be performed. According to another embodiment of the present disclosure, the terminal may perform uplink transmission by including uplink control information only in a subband on which CORESET#0 or SS/PBCH block transmission is configured. According to another embodiment of the present disclosure, the terminal may transmit an uplink signal by including uplink control information in a subband indicated by a base station through a higher layer signal or a control channel.

In addition, the terminal may also determine a subband to include uplink control information by a combination of one or more of the above-described methods. In this case, if the base station succeeds in decoding uplink control information in one specific subband, it may not perform uplink control information decoding for other subbands.

[Method 2]

According to one embodiment of the present disclosure, after performing a channel access procedure for each subband, the terminal may set a specific subband to transmit uplink control information according to a specific rule among at least one idle subband on which uplink transmission is to be performed. For example, the terminal may determine a specific subband using at least a combination of a terminal number (UE ID), an RNTI value, a CRC, and the number of idle subbands (K). As an example, the terminal may transmit an uplink signal including uplink control information in a subband of an index determined by mod(UE IDxRNTI, K).

In the above-described embodiments of the present disclosure, uplink signal transmission has been described as an example, but the method and device proposed in the embodiments of the present disclosure are not limited to uplink signal transmission and may also be applied to downlink signal transmission. For example, when a base station performs a channel access procedure for downlink signal transmission and transmits a downlink signal using consecutive subbands as a result of performing channel access truncation, the base station may transmit the downlink signal by including a guard band use/non-use indicator in a downlink control signal.

FIG. 12 is a flowchart illustrating base station operation according to one embodiment of the present disclosure.

In step 1200, the base station can transmit settings related to PDCCH, PDSCH, PUCCH, and PUSCH transmission and reception to the terminal through higher-level signaling. For example, the base station can transmit PDCCH resource region for receiving downlink or uplink scheduling information, CORESET settings, search space settings, etc. to the terminal through higher-level signaling. In addition, the base station can transmit settings related to PDSCH/PUSCH transmission and reception, including offset information between PDCCH reception slots, PDSCH reception slots, or PUSCH transmission slots, information on the number of PDSCH or PUSCH repetition transmissions, etc. to the terminal through higher-level signaling.

In step 1210, the base station may additionally transmit to the terminal configuration information related to grant-free, such as grant-free transmission period and offset information. At this time, it may also be possible for the grant-free configuration information transmitted to the terminal in step 1210 to be transmitted in step 1200.

If the base station performs uplink scheduling to the terminal within the channel occupancy interval acquired by the base station in step 1220, the base station can set up transmission gap interval-related information to the terminal in step 1230. For example, the base station can set uplink transmission by transmitting to the terminal a channel occupancy time (or frequency), a channel access procedure execution method (e.g. Type 3), a start symbol position of uplink transmission, or a downlink channel sharing indicator.

If the transmission gap interval set by the base station to the terminal in step 1240 satisfies a specific value or condition (e.g., 16 us or less), the base station can determine that the guard band between consecutive subbands has been used for uplink signal transmission when the terminal performs uplink transmission.

When the base station receives a guardband usage indicator or a channel access procedure result from the terminal in step 1270, the base station can determine that the guardband between consecutive subbands is used for uplink transmission, and can determine (or change) the mapping location of uplink control information.

FIG. 13 is a flowchart illustrating the operation of a terminal according to an embodiment of the present disclosure.

In step 1100, the terminal receives settings related to PDCCH, PDSCH, PUCCH, and PUSCH transmission and reception from the base station through an upper signal, and can configure settings related to PDCCH, PDSCH, PUCCH, and PUSCH transmission and reception according to the received configuration information. For example, the terminal can receive PDCCH resource area for receiving downlink or uplink scheduling information from the base station, or CORESET settings, search space settings, etc. through an upper signal.

In step 1310, the terminal can additionally receive grant-free-related configuration information, such as grant-free transmission cycle and offset information. At this time, the grant-free-related configuration information in step 1310 may also be included in the upper signal configuration information transmitted in step 1300.

If the terminal receives uplink scheduling within the channel occupancy interval acquired by the base station at step 1330, the terminal can receive transmission gap interval related information from the base station at step 1330. For example, the terminal can receive information such as channel occupancy time (or frequency), channel access procedure execution method (e.g. Type 3), start symbol position of uplink transmission, and downlink channel sharing indicator from the base station.

In step 1340, if the transmission gap interval set by the base station to the terminal satisfies a specific value or condition (for example, 16 us or less), the terminal can transmit an uplink signal using the guard band between consecutive subbands during uplink transmission.

When the terminal transmits a guardband usage indicator or a channel access procedure result to the base station in step 1370, the terminal can transmit an uplink signal using the guardband between consecutive subbands and change (or adjust) the location where uplink control information is transmitted.

[Example 5]

In this embodiment, a method is proposed for receiving a downlink signal or transmitting an uplink signal in a base station and a terminal configured to receive or transmit a downlink signal or an uplink signal in an unlicensed band when the terminal fails to receive a DCI indicating a slot format.

More specifically, a base station operating in an unlicensed band may not be able to perform downlink transmission if the channel is determined to be occupied as a result of a channel access procedure. For example, the base station may not be able to transmit a DCI indicating a slot format to a terminal. A terminal that has not been instructed about a slot format may not be able to perform uplink transmission or downlink reception set by the aforementioned upper signal, and performance degradation may occur as a result. The following proposes a method and device by which a terminal can transmit an uplink signal or receive a downlink signal.

Referring to FIG. 14, the operation of the terminal according to the present embodiment may be described as follows. The terminal may receive a DCI (e.g., DCI format 2_0) indicating a slot format in a time/frequency domain set by upper signaling, or may perform monitoring for the DCI indicating a slot format.

At this time, if the terminal misses the DCI indicating the slot format, or the base station fails to access the channel and thus fails to transmit the DCI indicating the slot format, the terminal may not be able to receive (or decode) the DCI (1400) indicating the slot format. At this time, the terminal may not transmit the uplink signal set as the upper signal or receive the downlink signal set as the upper signal for a predetermined time (1401) from the last symbol of the time domain in which the terminal is set to monitor or receive the DCI indicating the slot format. Here, the predetermined time (1401) may include at least a switching link (or PUSCH) preparation time (or processing time) or a downlink (or PDSCH) preparation time (or processing time) or a timing advance time.

In addition, the uplink signal set as the upper signal may include at least an uplink transmission that does not require scheduling (Configured grant PUSCH) or a periodic/aperiodic/semi-static SRS transmission or a PUCCH (or scheduling request) or a PRACH transmission. In addition, the downlink signal set as the upper signal may include at least a downlink transmission that does not require scheduling or a CSI-RS. Meanwhile, the terminal may transmit the uplink signal set as the upper signal for a specific time period (1403) from a predetermined time period (1401), for example, before the start symbol of a time domain in which DCI (1402) indicating the next slot format is to be monitored or received. At this time, the terminal may not receive the downlink signal set as the upper signal.

In order to perform the operation according to the above-described embodiment, the base station may set the terminal to perform the above-described operation through separate upper signaling or may instruct the terminal to perform the above-described operation through L1 signaling.

FIG. 15 is a block diagram illustrating an internal structure of a base station according to an embodiment of the present disclosure. As illustrated in FIG. 15, the base station of the present disclosure may include a processor (1510), a transceiver (1520), and a memory (1530). However, the components of the base station are not limited to the examples described above. For example, the terminal may include more or fewer components than the components described above. In addition, the processor (1510), the transceiver (1520), and the memory (1530) may be implemented in the form of a single chip. The transceiver (1520) and the processor (1510) may operate according to the communication method of the base station described above.

The transceiver (1520) can transmit and receive signals with the terminal. Here, the signals can include control information and data. To this end, the transceiver (1520) can be configured with an RF transmitter that up-converts and amplifies the frequency of a transmitted signal, an RF receiver that low-noise amplifies a received signal, and down-converts the frequency. However, this is only one embodiment of the transceiver (1520), and the components of the transceiver (1520) are not limited to the RF transmitter and RF receiver.

Additionally, the transceiver (1520) can receive a signal through a wireless channel and output it to the processor (1510), and transmit a signal output from the processor (1510) through the wireless channel.

The processor (1510) 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 one embodiment of the present disclosure, the processor (1510) may perform a channel access procedure for an unlicensed band. For example, the processor (1510) may receive signals transmitted in an unlicensed band through the transceiver (1520), and may compare the intensity of the received signal, etc. with a value of a function that is defined in advance or has a bandwidth as a factor, a determined threshold value, etc., to determine whether the unlicensed band is in an idle state. In addition, the processor (1510) may change or reset an uplink signal reception method according to uplink control information transmitted by a terminal.

The memory (1530) can store programs and data required for the operation of the base station. In addition, the memory (1530) can store control information or data included in a signal acquired from the base station. The memory (1530) can include a memory configured as a storage medium or a combination of storage media, such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD. In addition, the memory (1530) can be configured as a plurality of memories.

FIG. 16 is a block diagram illustrating an internal structure of a terminal according to an embodiment of the present disclosure. As illustrated in FIG. 16, the terminal of the present disclosure may include a processor (1610), a transceiver (1620), and a memory (1630). However, the components of the terminal are not limited to the above-described examples. For example, the terminal may include more or fewer components than the components described above. In addition, the processor (1610), the transceiver (1620), and the memory (1630) may be implemented in the form of a single chip.

The transceiver (1620) can transmit and receive signals with the base station. The above-described signals can include control information and data. To this end, the transceiver (1620) can be configured with an RF transmitter that up-converts and amplifies the frequency of a transmitted signal, an RF receiver that low-noise amplifies a received signal and down-converts the frequency, etc. In addition, the transceiver (1620) can receive a signal through a wireless channel and output it to the processor (1610), and transmit a signal output from the processor (1610) through the wireless channel.

The processor (1610) may control a series of processes so that the terminal may operate according to the above-described embodiment of the present disclosure. For example, the processor (1610) may receive a data signal including a control signal through the transceiver (1620) and determine a reception result for the data signal. Thereafter, when the first signal reception result including the data reception at the above-described timing must be transmitted to the base station, the processor (1610) may cause the transceiver (1620) to transmit the first signal reception result described above to the base station at the determined timing. As another example, the processor (1610) may generate information that enables the base station to determine uplink reception and reception method as uplink control information. At this time, the control information may be changed according to the result of performing the channel access procedure and the uplink signal generation method.

Meanwhile, the embodiments of the present disclosure disclosed in the specification and drawings are only intended to easily explain the technical contents of the present disclosure and to provide specific examples to help understand the present disclosure, and are not intended to limit the scope of the present disclosure. That is, it will be apparent to a person having ordinary skill in the art to which the present disclosure pertains that other modified examples based on the technical idea of the present disclosure are possible. In addition, each of the embodiments described above may be combined and operated with each other as needed. 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 embodiments described above have been presented based on the 5G, NR system, other modified examples based on the technical idea of the embodiments described above may be implemented with other systems such as LTE, LTE-A, LTE-A-Pro systems, and V2X.

Claims (20)

In a method of a user equipment (UE) in a wireless communication system, the method comprises:
A step of identifying a first idle subband and a second idle subband within an unlicensed band; and
A step of transmitting an uplink signal including uplink control information (UCI) to a base station (BS) in at least one of the first idle subband and the second idle subband;
The first idle subband and the second idle subband are continuous,
The above uplink control information includes information indicating whether a guard band between the first idle subband and the second idle subband is used for uplink transmission,
A method wherein the uplink signal is decoded based on the uplink control information. In the method of paragraph 1,
The guard band includes a first guard band within the first idle subband and a second guard band within the second idle subband adjacent to the first guard band,
The above first guard band protects the channel access procedure (listen before talk, LBT) performed in the second idle subband,
A method wherein the second guard band protects a channel access procedure performed in the first idle subband. In the method of claim 1, the uplink control information is transmitted in one of the first idle subband and the second idle subband. A method according to claim 1, wherein the uplink control information is not transmitted in the guard band. A method according to claim 1, wherein the uplink control information includes information of the first idle subband and information of the second idle subband. In the method of Article 5,
The above uplink control information includes first uplink control information and second uplink control information,
A method wherein the second uplink control information includes information of the first idle subband and information of the second idle subband. In the method of claim 6, the resources used to transmit the second uplink control information are indicated by the base station. A method according to claim 6, wherein the first uplink control information includes information that resources used to transmit the second uplink control information are indicated by the first uplink control information. In the method of claim 1, the step of identifying a first idle subband and a second idle subband in the unlicensed band comprises:
A step of performing a channel access procedure in each of a plurality of subbands within the above unlicensed band; and
A method comprising: a step of identifying the first idle subband and the second idle subband based on a result of performing the channel access procedure; In a method of a base station (BS) in a wireless communication system, the method comprises:
A step of receiving an uplink signal including uplink control information from a user equipment (UE) in at least one of a first idle subband and a second idle subband within an unlicensed band; and
A step of decoding the uplink signal based on the uplink control information; comprising:
The first idle subband and the second idle subband are continuous,
The first idle subband and the second idle subband are included in the idle subbands identified by the user device within the unlicensed band,
A method wherein the uplink control information includes information indicating whether a guard band between the first idle subband and the second idle subband is used for uplink transmission. In the method of Article 10,
The guard band includes a first guard band within the first idle subband and a second guard band within the second idle subband adjacent to the first guard band,
The above first guard band protects the channel access procedure (listen before talk, LBT) performed in the second idle subband,
A method wherein the second guard band protects a channel access procedure performed in the first idle subband. In the method of claim 10, the uplink control information is transmitted in one of the first idle subband and the second idle subband. A method according to claim 10, wherein the uplink control information is not transmitted in the guard band. A method according to claim 10, wherein the uplink control information includes information on the identified idle subbands. In the method of Article 14,
The above uplink control information includes first uplink control information and second uplink control information,
A method wherein the second uplink control information includes information about the identified idle subbands. In the method of claim 15, the resources used to transmit the second uplink control information are indicated by the base station. A method according to claim 15, wherein the first uplink control information includes information that resources used to transmit the second uplink control information are indicated by the first uplink control information. In the method of Article 10,
A method wherein the first idle subband and the second idle subband are identified by the user device as idle subbands based on a result of performing a channel access procedure on each of a plurality of subbands within the unlicensed band. In a wireless communication system, in a user equipment (UE), the user equipment,
Transmitter and receiver; and
At least one processor coupled to the transceiver; comprising:
Identifying a first idle subband and a second idle subband within the unlicensed band,
In at least one of the first idle subband and the second idle subband, an uplink signal including uplink control information (UCI) is transmitted to a base station (BS),
The first idle subband and the second idle subband are continuous,
The above uplink control information includes information indicating whether a guard band between the first idle subband and the second idle subband is used for uplink transmission,
A user device in which the uplink signal is decoded based on the uplink control information. In a wireless communication system, at a base station (BS), the base station,
Transmitter and receiver; and
At least one processor coupled to the transceiver; comprising:
Receiving an uplink signal including uplink control information from a user equipment (UE) in at least one of a first idle subband and a second idle subband in an unlicensed band,
Based on the above uplink control information, the uplink signal is decoded,
The first idle subband and the second idle subband are continuous,
The first idle subband and the second idle subband are included in the idle subbands identified by the user device within the unlicensed band,
A base station, wherein the uplink control information includes information indicating whether a guard band between the first idle subband and the second idle subband is used for uplink transmission.