KR20200008501A - Method and apparatus for performing wireless communication in unlicensed band - Google Patents

Abstract

Embodiments of the present invention relate to a method and apparatus for performing wireless communication in an unlicensed band. According to an embodiment of the present invention, provided is a method of a terminal for performing wireless communication in an unlicensed band, which comprises the steps of: receiving information for allocating radio resources in a system band consisting of a plurality of subbands; receiving information about a failure region of listen before talk (LBT) among the radio resources; monitoring a downlink signal in a region excluding the LBT failure region from the radio resources; and receiving the downlink signal.

Description

METHOD AND APPARATUS FOR PERFORMING WIRELESS COMMUNICATION IN UNLICENSED BAND}

The present embodiments propose a method and apparatus for performing wireless communication in consideration of a failure before talk (LBT) for an unlicensed band in a next generation wireless access network (hereinafter referred to as "NR (New Radio)").

3GPP recently approved a study item "Study on New Radio Access Technology" for the study of next-generation radio access technology (that is, 5G radio access technology). Designs for frame structures, channel coding & modulation, waveforms and multiple access schemes are in progress. The NR is required to be designed to satisfy various QoS requirements required for each detailed and detailed usage scenario as well as improved data rate compared to LTE.

As representative usage scenarios of NR, enhancement mobile broadband (eMBB), massive machine type communication (MMTC), and ultra reliable and low latency communications (URLLC) are defined, and flexible frame structure compared to LTE to satisfy the needs of each usage scenario. Design is required.

Each service scenario has different requirements for data rates, latency, reliability, coverage, and so on, through the frequency bands that make up any NR system. As a method for efficiently satisfying the needs of each usage scenario, based on different numerology (for example, subcarrier spacing, subframe, transmission time interval, etc.) There is a need for a method of efficiently multiplexing radio resource units of a network.

As part of this aspect, there is a need for a design for performing wireless communication in accordance with the results of the LBT performed for a plurality of subbands constituting an unlicensed band in the NR.

Embodiments of the present disclosure provide a specific method and apparatus that can efficiently perform wireless communication when some of the subbands of the resource is not available when resource allocation is performed over a plurality of subbands in an unlicensed band. can do.

In addition, embodiments of the present disclosure may provide a specific method and apparatus capable of transmitting information on an LBT failure area that is a subband in an unused state when resource allocation is performed over a plurality of subbands in an unlicensed band. .

In one aspect, the present embodiment is a method for a terminal to perform wireless communication in an unlicensed band, the method comprising: receiving information for allocating radio resources in a system band consisting of a plurality of subbands, Listen Before Talk among the radio resources The method may include receiving information on a failure area, monitoring a downlink signal in an area excluding the LBT failure area from a radio resource, and receiving a downlink signal.

In another aspect, embodiments of the present invention provide a method for a base station to perform wireless communication in an unlicensed band, including performing List Before Talk (LBT) for each subband in a system band including a plurality of subbands, in a system band. The method may include transmitting information for allocating a radio resource, transmitting information on an LBT failure area among radio resources, and transmitting a downlink signal in an area except the LBT failure area in the radio resource. have.

In another aspect, the embodiments of the present invention, in a terminal performing wireless communication in an unlicensed band, receives information for allocating radio resources in a system band composed of a plurality of subbands, and provides information on an LBT failure area among radio resources. A terminal including a receiving unit and a control unit for receiving a downlink signal by monitoring a downlink signal in a region excluding an LBT failure region in a radio resource may be provided.

In another aspect, the present embodiment is a base station for performing wireless communication in the unlicensed band, the control unit for performing the LBT (Listen Before Talk) for each subband in a system band consisting of a plurality of subbands and wireless in the system band The base station may include a transmitter that transmits information for allocating resources, transmits information on an LBT failure area of a radio resource, and transmits a downlink signal in an area excluding the LBT failure area in a radio resource.

According to the present embodiments, when resource allocation is performed over a plurality of subbands in an unlicensed band, wireless communication in an unlicensed band enables efficient wireless communication when some of the subbands of the corresponding resource are not available. It can provide a method and apparatus for performing the.

In addition, according to the present embodiments, when resource allocation is performed over a plurality of subbands in an unlicensed band, by transmitting information on an LBT failure area that is an unused subband, some of the subbands of the corresponding resource may be It is possible to provide a method and apparatus for performing wireless communication in an unlicensed band that enables efficient wireless communication even in a busy state.

1 is a diagram schematically illustrating a structure of an NR wireless communication system to which an embodiment of the present invention may be applied.
2 is a view for explaining a frame structure in an NR system to which the present embodiment can be applied.
3 is a diagram for describing a resource grid supported by a radio access technology to which an embodiment of the present invention can be applied.
4 is a diagram for describing a bandwidth part supported by a radio access technology to which an embodiment of the present invention can be applied.
5 is a diagram exemplarily illustrating a synchronization signal block in a radio access technology to which the present embodiment can be applied.
FIG. 6 is a diagram for explaining a random access procedure in a radio access technology to which the present embodiment can be applied.
7 is a diagram for explaining CORESET.
FIG. 8 is a diagram illustrating an example of symbol level alignment among different SCSs in different SCSs to which the present embodiment can be applied.
FIG. 9 is a diagram illustrating a conceptual example of a bandwidth part to which the present embodiment can be applied.
10 is a diagram illustrating a procedure of performing wireless communication by a terminal using information on an LBT failure region in an unlicensed band according to an embodiment.
FIG. 11 is a diagram illustrating a procedure in which a base station performs wireless communication using information on an LBT failure area in an unlicensed band according to an embodiment.
12 illustrates an example of performing LBT for wireless communication in an unlicensed band according to an embodiment.
13 illustrates a subband of an unlicensed band according to an embodiment.
14 is a diagram for describing a transmission area in a case where multiple starting points are supported in an unlicensed band according to an embodiment.
15 and 16 are diagrams for describing a DCI format including information on an LBT failure area, according to an embodiment.
17 is a diagram illustrating a configuration of a user terminal according to another embodiment.
18 is a diagram illustrating a configuration of a base station according to another embodiment.

Hereinafter, some embodiments of the present disclosure will be described in detail with reference to exemplary drawings. In adding reference numerals to components of each drawing, the same components may have the same reference numerals as much as possible even though they are shown in different drawings. In addition, in describing the present embodiments, when it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description may be omitted. When "include", "have", "consist", or the like, as used herein, other parts may be added unless "only" is used. In the singular form, the plural may include the plural unless specifically stated otherwise.

In addition, in describing the components of the present disclosure, terms such as first, second, A, B, (a), and (b) may be used. These terms are only to distinguish the components from other components, and the terms are not limited in nature, order, order or number of the components.

In the description of the positional relationship of components, when two or more components are described as being "connected", "coupled" or "connected", the two or more components are directly "connected", "coupled" or "connected". It may be understood, but it should be understood that two or more components and other components may be further “interposed” and “connected”, “coupled” or “connected”. Here, the other components may be included in one or more of two or more components that are "connected", "coupled" or "connected" to each other.

In the description of the temporal flow relations with respect to the components, the operation method, the fabrication method, and the like, for example, the temporal relationship between the temporal relationship of " after, ", " after, " Or where flow-benefit relationships are described, they may also include cases where they are not continuous unless "right" or "direct" is used.

On the other hand, when numerical values or corresponding information (e.g., levels) for the component are mentioned, the numerical values or corresponding information may be various factors (e.g., process factors, internal or external shocks, It may be interpreted as including an error range that may be caused by noise).

The wireless communication system in the present specification means a system for providing various communication services such as voice and data packets using radio resources, and may include a terminal, a base station, or a core network.

The embodiments disclosed below can be applied to a wireless communication system using various radio access technologies. For example, the embodiments of the present invention may include code division multiple access (CDMA), frequency division multiple access (FDMA), timedivision multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), and single carrier frequency division multiple access (SC-FDMA). Alternatively, the present invention may be applied to various radio access technologies such as non-orthogonal multiple access (NOMA). In addition, the wireless access technology may mean not only a specific access technology but also a communication technology for each generation established by various communication consultation organizations such as 3GPP, 3GPP2, WiFi, Bluetooth, IEEE, and ITU. For example, CDMA may be implemented with a radio technology such as universal terrestrial radio access (UTRA) or CDMA2000. TDMA may be implemented in a radio technology such as global system for mobile communications (GSM) / general packet radio service (GPRS) / enhanced data rates for GSM evolution (EDGE). OFDMA may be implemented in wireless technologies such as Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, evolved UTRA (E-UTRA), and the like. IEEE 802.16m is an evolution of IEEE 802.16e and provides backward compatibility with systems based on IEEE 802.16e. UTRA is part of a universal mobile telecommunications system (UMTS). 3rd generation partnership project (3GPP) long term evolution (LTE) is part of evolved UMTS (E-UMTS) using evolved-UMTS terrestrial radio access (E-UTRA), employing OFDMA in downlink and SC- in uplink FDMA is adopted. As such, the embodiments may be applied to a wireless access technology that is currently disclosed or commercialized, and may be applied to a wireless access technology that is currently under development or will be developed in the future.

Meanwhile, the terminal in the present specification is a comprehensive concept of a device including a wireless communication module for performing communication with a base station in a wireless communication system, and in WCDMA, LTE, NR, HSPA, and IMT-2020 (5G or New Radio), etc. In addition to the user equipment (UE), as well as MS (Mobile Station), User Interface (UT), Subscriber Station (SS), a wireless device (wireless device) and the like in GSM should be interpreted. In addition, the terminal may be a user portable device such as a smart phone according to a usage form, and in the V2X communication system, it may mean a vehicle, a device including a wireless communication module in the vehicle, and the like. In addition, in the case of a machine type communication system, it may mean an MTC terminal, an M2M terminal, a URLLC terminal, etc. equipped with a communication module to perform machine type communication.

A base station or a cell of the present specification refers to an end point that communicates with a terminal in terms of a network, and includes a Node-B, an evolved Node-B, an eNB, a gNode-B, a Low Power Node, and an LPN. Sector, site, various types of antenna, base transceiver system (BTS), access point, point (for example, transmission point, reception point, transmission / reception point), relay node ), A mega cell, a macro cell, a micro cell, a pico cell, a femto cell, a remote radio head (RRH), a radio unit (RU), and a small cell. In addition, the cell may mean a bandwidth part (BWP) in the frequency domain. For example, the serving cell may mean an activation BWP of the terminal.

Since the above-described various cells have a base station that controls one or more cells, the base station may be interpreted in two meanings. 1) the device providing the mega cell, the macro cell, the micro cell, the pico cell, the femto cell, the small cell in relation to the radio area, or 2) the radio area itself. In 1) all devices that provide a given wireless area are controlled by the same entity or interact with each other to cooperatively configure the wireless area to the base station. According to the configuration of the wireless area, a point, a transmission point, a transmission point, a reception point, and the like become one embodiment of a base station. In 2), the base station may indicate the radio area itself that receives or transmits a signal from the viewpoint of the user terminal or the position of a neighboring base station.

In the present specification, a cell refers to a component carrier having coverage of a signal transmitted from a transmission / reception point or a signal transmitted from a transmission point or a transmission / reception point, and the transmission / reception point itself. Can be.

Uplink (UL, or uplink) means a method for transmitting and receiving data to the base station by the terminal, downlink (Downlink, DL, or downlink) means a method for transmitting and receiving data to the terminal by the base station do. Downlink (downlink) may mean a communication or communication path from the multiple transmission and reception points to the terminal, uplink (uplink) may mean a communication or communication path from the terminal to the multiple transmission and reception points. In this case, in the downlink, the transmitter may be part of multiple transmission / reception points, and the receiver may be part of the terminal. In addition, in uplink, a transmitter may be part of a terminal, and a receiver may be part of multiple transmission / reception points.

The uplink and the downlink transmit and receive control information through control channels such as a physical downlink control channel (PDCCH), a physical uplink control channel (PUCCH), a physical downlink shared channel (PDSCH), a physical uplink shared channel (PUSCH), and the like. Configure the same data channel to send and receive data. Hereinafter, a situation in which a signal is transmitted and received through a channel such as a PUCCH, a PUSCH, a PDCCH, and a PDSCH may be described in the form of 'sending and receiving a PUCCH, a PUSCH, a PDCCH, and a PDSCH.'

For clarity, the following description focuses on the 3GPP LTE / LTE-A / NR (New RAT) communication system, but the present technical features are not limited to the communication system.

After researching 4G (4th-Generation) communication technology, 3GPP develops 5G (5th-Generation) communication technology to meet the requirements of ITU-R's next generation wireless access technology. Specifically, 3GPP develops a new NR communication technology separate from LTE-A pro and 4G communication technology, which is an enhancement of LTE-Advanced technology to the requirements of ITU-R with 5G communication technology. Both LTE-A pro and NR mean 5G communication technology. Hereinafter, 5G communication technology will be described based on NR when a specific communication technology is not specified.

Operational scenarios in NR defined various operational scenarios by adding considerations to satellites, automobiles, and new verticals in the existing 4G LTE scenarios.In terms of service, they have an eMBB (Enhanced Mobile Broadband) scenario and a high terminal density. Supports a range of mass machine communication (MMTC) scenarios that require low data rates and asynchronous connections, and Ultra Reliability and Low Latency (URLLC) scenarios that require high responsiveness and reliability and support high-speed mobility. .

In order to satisfy this scenario, NR discloses a wireless communication system using a new waveform and frame structure technology, low latency technology, mmWave support technology, and forward compatible technology. In particular, the NR system proposes various technological changes in terms of flexibility to provide forward compatibility. The main technical features of the NR will be described with reference to the drawings below.

<NR system general>

1 is a diagram briefly showing a structure of an NR system to which the present embodiment may be applied.

Referring to FIG. 1, an NR system is divided into a 5G core network (5GC) and an NR-RAN part, and the NG-RAN controls a user plane (SDAP / PDCP / RLC / MAC / PHY) and a user equipment (UE). It consists of gNB and ng-eNBs that provide planar (RRC) protocol termination. The gNB interconnects or gNBs and ng-eNBs are interconnected via an Xn interface. gNB and ng-eNB are each connected to 5GC through the NG interface. The 5GC may be configured to include an access and mobility management function (AMF) for controlling a control plane such as a terminal access and mobility control function, and a user plane function (UPF) for controlling a user data. NR includes support for sub-6 GHz frequency bands (FR1, Frequency Range 1) and 6 GHz and higher frequency bands (FR2, Frequency Range 2).

gNB means a base station that provides NR user plane and control plane protocol termination to the terminal, and ng-eNB means a base station that provides E-UTRA user plane and control plane protocol termination to the terminal. The base station described in the present specification should be understood to mean gNB and ng-eNB, and may be used to mean gNB or ng-eNB separately.

NR Waveforms, Numelar and Frame Structures

In NR, a CP-OFDM waveform using a cyclic prefix is used for downlink transmission, and a CP-OFDM or DFT-s-OFDM is used for uplink transmission. OFDM technology is easy to combine with Multiple Input Multiple Output (MIMO), and has the advantage of using a low complexity receiver with high frequency efficiency.

On the other hand, in NR, since the requirements for data rate, delay rate, and coverage are different for each of the three scenarios described above, it is necessary to efficiently satisfy the requirements of each scenario through a frequency band constituting an arbitrary NR system. . To this end, a technique for efficiently multiplexing a plurality of different numerology-based radio resources has been proposed.

Specifically, the NR transmission neuron is determined based on sub-carrier spacing and cyclic prefix (CP), and μ is used as an exponent value of 2 based on 15 kHz as shown in Table 1 below. Is changed to.

μ Subcarrier spacing Cyclic prefix Supported for data Supported for synch 0 15 Normal Yes Yes One 30 Normal Yes Yes 2 60 Normal, Extended Yes No 3 120 Normal Yes Yes 4 240 Normal No Yes

As shown in Table 1 above, the NR's neuronality may be classified into five types according to the subcarrier spacing. This is different from the LTE subcarrier spacing, which is one of the 4G communication technologies, fixed at 15 kHz. Specifically, the subcarrier intervals used for data transmission in NR are 15, 30, 60, and 120 kHz, and the subcarrier intervals used for synchronization signal transmission are 15, 30, 12, and 240 kHz. In addition, the extended CP applies only to 60 kHz subcarrier intervals. On the other hand, the frame structure (frame) in NR is a frame having a length of 10ms consisting of 10 subframes having the same length of 1ms is defined. One frame may be divided into half frames of 5 ms, and each half frame includes five subframes. In the case of a 15 kHz subcarrier interval, one subframe consists of one slot and each slot consists of 14 OFDM symbols. 2 is a view for explaining a frame structure in an NR system to which the present embodiment can be applied.

Referring to FIG. 2, the slot is fixedly configured with 14 OFDM symbols in the case of a normal CP, but the length of the slot may vary according to the subcarrier spacing. For example, in the case of a numerology having a 15 kHz subcarrier spacing, the slot is configured to have a length equal to a subframe of 1 ms in length. On the contrary, in the case of a numerology having a 30 kHz subcarrier interval, the slot is composed of 14 OFDM symbols, but two slots may be included in one subframe with a length of 0.5 ms. That is, the subframe and the frame are defined with a fixed time length, the slot is defined by the number of symbols, the time length may vary according to the subcarrier interval.

Meanwhile, NR defines a basic unit of scheduling as a slot and also introduces a mini slot (or subslot or non-slot based schedule) to reduce transmission delay of a radio section. The use of a wide subcarrier spacing shortens the length of one slot inversely, thus reducing the transmission delay in the radio section. The mini slot (or sub slot) is for efficient support for the URLLC scenario and can be scheduled in units of 2, 4, and 7 symbols.

In addition, unlike LTE, NR defines uplink and downlink resource allocation at a symbol level in one slot. In order to reduce the HARQ delay, a slot structure capable of transmitting HARQ ACK / NACK in a transmission slot is defined, and this slot structure is described as a self-contained structure.

NR is designed to support a total of 256 slot formats, of which 62 slot formats are used in 3GPP Rel-15. In addition, the combination of various slots supports a common frame structure constituting an FDD or TDD frame. For example, a slot structure in which all symbols of a slot are set to downlink, a slot structure in which all symbols are set to uplink, and a slot structure in which downlink symbol and uplink symbol are combined are supported. NR also supports that data transmission is distributed and scheduled in one or more slots. Accordingly, the base station can inform the terminal whether the slot is a downlink slot, an uplink slot, or a flexible slot by using a slot format indicator (SFI). The base station may indicate the slot format by indicating an index of a table configured through UE-specific RRC signaling using SFI, and may indicate the slot format dynamically through DCI (Downlink Control Information) or statically through RRC. You can also specify quasi-statically.

<NR Physical Resource>

With regard to physical resources in NR, antenna ports, resource grids, resource elements, resource blocks, bandwidth parts, etc. are considered do.

The antenna port is defined so that the channel on which the symbol is carried on the antenna port can be inferred from the channel on which another symbol on the same antenna port is carried. If the large-scale property of a channel on which a symbol on one antenna port is carried can be deduced from the channel on which the symbol on another antenna port is carried, then the two antenna ports are quasi co-located or QC / QCL. quasi co-location relationship. Here, the broad characteristics include one or more of delay spread, Doppler spread, frequency shift, average received power, and received timing.

3 is a diagram for describing a resource grid supported by a radio access technology to which an embodiment of the present invention can be applied.

Referring to FIG. 3, since the Resource Grid supports a plurality of numerologies in the same carrier, a resource grid may exist according to each neuralology. In addition, the resource grid may exist according to antenna ports, subcarrier spacing, and transmission direction.

The resource block consists of 12 subcarriers and is defined only in the frequency domain. In addition, a resource element is composed of one OFDM symbol and one subcarrier. Accordingly, as shown in FIG. 3, one resource block may vary in size depending on the subcarrier spacing. In addition, the NR defines "Point A" serving as a common reference point for the resource block grid, a common resource block, a virtual resource block, and the like.

4 is a diagram for describing a bandwidth part supported by a radio access technology to which an embodiment of the present invention can be applied.

In NR, unlike LTE, which has a fixed carrier bandwidth of 20 MHz, the maximum carrier bandwidth is set from 50 MHz to 400 MHz per subcarrier interval. Therefore, it is not assumed that all terminals use all of these carrier bandwidths. Accordingly, in the NR, as shown in FIG. 4, the UE designates a bandwidth part (BWP) within the carrier bandwidth. In addition, the bandwidth part is associated with one neuralology and consists of a subset of consecutive common resource blocks, and can be dynamically activated over time. The UE is configured with up to four bandwidth parts, respectively, for uplink and downlink, and data is transmitted and received using the bandwidth part activated at a given time.

In the case of paired spectrum, uplink and downlink bandwidth parts are set independently, and in the case of unpaired spectrum, to prevent unnecessary frequency re-tunning between downlink and uplink operation. For this purpose, the bandwidth parts of the downlink and the uplink are configured in pairs so as to share the center frequency.

<NR initial connection>

In NR, the UE performs a cell search and random access procedure to access and communicate with a base station.

Cell search is a procedure in which a terminal synchronizes with a cell of a corresponding base station, acquires a physical layer cell ID, and obtains system information by using a synchronization signal block (SSB) transmitted by a base station.

5 is a diagram exemplarily illustrating a synchronization signal block in a radio access technology to which the present embodiment can be applied.

Referring to FIG. 5, the SSB is composed of a primary synchronization signal (PSS) and a secondary synchronization signal (SSS), which occupy one symbol and 127 subcarriers, respectively, three OFDM symbols, and a PBCH spanning 240 subcarriers.

The terminal monitors the SSB in time and frequency domain and receives the SSB.

SSB can be transmitted up to 64 times in 5ms. A plurality of SSBs are transmitted in different transmission beams within 5 ms time, and the UE performs detection assuming that the SSB is transmitted every 20 ms period based on a specific beam used for transmission. The number of beams that can be used for SSB transmission within 5 ms time may increase as the frequency band increases. For example, up to 4 SSB beams may be transmitted at 3 GHz or less, and up to 8 different SSBs may be transmitted in a frequency band of 3 to 6 GHz and up to 64 different beams in a frequency band of 6 GHz or more.

Two SSBs are included in one slot, and the start symbol and the number of repetitions in the slot are determined according to the subcarrier spacing.

On the other hand, the SSB is not transmitted at the center frequency of the carrier bandwidth, unlike the SS of the conventional LTE. That is, the SSB may be transmitted even where the center of the system band is not, and when supporting broadband operation, a plurality of SSBs may be transmitted in the frequency domain. Accordingly, the terminal monitors the SSB using a synchronization raster, which is a candidate frequency location for monitoring the SSB. The carrier raster and the synchronization raster, which are the center frequency position information of the channel for initial access, are newly defined in the NR, and the synchronization raster has a wider frequency interval than the carrier raster, and thus supports fast SSB search of the terminal. Can be.

The UE may acquire the MIB through the PBCH of the SSB. The Master Information Block (MIB) includes minimum information for the UE to receive the remaining system information (RMSI) that the network broadcasts. In addition, the PBCH is information on the position of the first DM-RS symbol in the time domain, information for the UE to monitor SIB1 (for example, SIB1 neuronological information, information related to SIB1 CORESET, search space information, PDCCH Related parameter information, etc.), offset information between the common resource block and the SSB (the position of the absolute SSB in the carrier is transmitted through SIB1), and the like. Here, the SIB1 neuronological information is equally applied to some messages used in a random access procedure for accessing a base station after the terminal completes a cell search procedure. For example, the neuralology information of SIB1 may be applied to at least one of messages 1 to 4 for the random access procedure.

The aforementioned RMSI may refer to System Information Block 1 (SIB1), which is broadcast periodically (ex, 160ms) in the cell. SIB1 includes information necessary for the UE to perform an initial random access procedure and is periodically transmitted through the PDSCH. In order to receive the SIB1, the UE needs to receive the information on the neuterology used for the SIB1 transmission and the control resource set (CORESET) information used for the scheduling of the SIB1 through the PBCH. The UE checks scheduling information on SIB1 using SI-RNTI in CORESET and obtains SIB1 on PDSCH according to the scheduling information. The remaining SIBs except for SIB1 may be periodically transmitted or may be transmitted at the request of the UE.

FIG. 6 is a diagram for explaining a random access procedure in a radio access technology to which the present embodiment can be applied.

Referring to FIG. 6, when the cell search is completed, the terminal transmits a random access preamble for random access to the base station. The random access preamble is transmitted on the PRACH. Specifically, the random access preamble is transmitted to the base station through a PRACH composed of consecutive radio resources in a specific slot that is periodically repeated. In general, when a UE initially accesses a cell, a contention-based random access procedure is performed, and when a UE performs random access for beam failure recovery (BFR), a contention-free random access procedure is performed.

The terminal receives a random access response to the transmitted random access preamble. The random access response may include a random access preamble identifier (ID), an UL grant (uplink radio resource), a temporary C-RNTI (Temporary Cell-Radio Network Temporary Identifier), and a time alignment command (TAC). Since one random access response may include random access response information for one or more terminals, the random access preamble identifier may be included to indicate to which UE the included UL Grant, temporary C-RNTI, and TAC are valid. The random access preamble identifier may be an identifier for the random access preamble received by the base station. The TAC may be included as information for the UE to adjust uplink synchronization. The random access response may be indicated by a random access identifier on the PDCCH, that is, a random access-radio network temporary identifier (RA-RNTI).

Upon receiving the valid random access response, the terminal processes the information included in the random access response and performs the scheduled transmission to the base station. For example, the terminal applies TAC and stores a temporary C-RNTI. In addition, by using the UL Grant, data or newly generated data stored in the buffer of the terminal is transmitted to the base station. In this case, information to identify the terminal should be included.

Finally, the terminal receives a downlink message for contention resolution.

<NR CORESET>

The downlink control channel in NR is transmitted in a control resource set (CORESET) having a length of 1 to 3 symbols, and transmits up / down scheduling information, slot format index (SFI), and transmit power control (TPC) information. .

As such, the NR introduced the concept of CORESET in order to secure system flexibility. CORESET (Control Resource Set) means a time-frequency resource for the downlink control signal. The terminal may decode the control channel candidate using one or more search spaces in the CORESET time-frequency resource. The QCL (Quasi CoLocation) assumption for each CORESET has been set, which is used to inform the analog beam direction in addition to the delay spread, Doppler spread, Doppler shift, and average delay, which are assumed by conventional QCL.

7 is a diagram for explaining CORESET.

Referring to FIG. 7, CORESET may exist in various forms within a carrier bandwidth in one slot, and CORESET may be configured with up to three OFDM symbols in the time domain. In addition, CORESET is defined as a multiple of six resource blocks up to the carrier bandwidth in the frequency domain.

The first CORESET is indicated through the MIB as part of the initial bandwidth part configuration to receive additional configuration information and system information from the network. After establishing the connection with the base station, the terminal may receive and configure one or more CORESET information through RRC signaling.

In this specification, a frequency, frame, subframe, resource, resource block, region, band, subband, control channel, data channel, synchronization signal, various reference signals, various signals, or various messages related to NR (New Radio). May be interpreted as meaning used in the past or present or various meanings used in the future.

NR (New Radio)

3GPP recently approved “Study on New Radio Access Technology”, a study item for research on next-generation radio access technology (ie 5G radio access technology), and based on this, RAN WG1 has a frame structure for each new radio (NR). (frame structure), channel coding and modulation (waveform and multiple access scheme), etc. design is in progress. NR is required to be designed to meet various QoS requirements required for each detailed and detailed service scenario as well as improved data rate compared to LTE / LTE-Advanced.

As typical service scenarios for NR, enhancement Mobile BroadBand (eMBB), massive machine type communication (MMTC), and Ultra Reliable and Low Latency Communications (URLLC) are defined and meet the needs of each service scenario. As a method for doing so, a flexible frame structure design is required compared to LTE / LTE-Advanced.

Each service scenario is a frequency constituting an arbitrary NR system because the requirements for data rates, latency, reliability, coverage, etc. are different from each other. A radio resource unit based on different numerology (eg, subcarrier spacing, subframe, TTI, etc.) as a method for efficiently satisfying each service scenario needs through the band. There is a need for a method of efficiently multiplexing (multiplexing).

As a method for this, TDM, FDM or TDM / FDM based on one or a plurality of NR component carriers (s) for numerology having different subcarrier spacing values. As a method of supporting multiplexing and a scheduling unit in a time domain, a method of supporting one or more time units has been discussed. In this regard, in NR, a subframe is defined as a kind of time domain structure, and reference numerology is used to define a subframe duration. As the LTE, it was decided to define a single subframe duration consisting of 14 OFDM symbols of the same 15kHz sub-carrier spacing (SCS) -based normal CP overhead. Accordingly, the subframe in NR has a time duration of 1 ms. However, unlike LTE, subframes of NR are absolute reference time durations, and slots and mini-slots are time units based on actual uplink / downlink data scheduling. ) Can be defined. In this case, the number of OFDM symbols and the y value of the corresponding slot are determined to have a value of y = 14 regardless of the SCS value in the case of normal CP.

Accordingly, any slot consists of 14 symbols, and according to the transmission direction of the slot, all symbols are used for DL transmission, or all symbols are UL transmission (UL). It may be used for transmission or in the form of a DL portion + a gap + an UL portion.

In addition, a short slot time-domain scheduling interval for transmitting / receiving uplink / downlink data is defined based on a mini-slot consisting of fewer symbols than the slot in an arbitrary number (numerology) (or SCS). A scheduling interval may be set or a long time-domain scheduling interval for transmitting / receiving uplink / downlink data may be configured through slot aggregation.

In particular, in case of transmission / reception of latency critical data such as URLLC, it is based on 1ms (14 symbols) defined in a numerology-based frame structure with a small SCS value such as 15 kHz. When scheduling is performed by slot unit, it may be difficult to satisfy the latency requirement, so for this purpose, a mini slot consisting of fewer OFDM symbols than the corresponding slot is defined and based on this, critical to the same delay rate as the corresponding URLLC. (latency critical) can be defined to be scheduled for the data.

Alternatively, as described above, by supporting multiplexing by using the TDM and / or FDM method, a number of numerology having different SCS values in one NR carrier is supported for each numerology. Scheduling data according to a latency requirement based on a defined slot (or mini slot) length is also considered. For example, as shown in FIG. 8 below, when the SCS is 60 kHz, since the symbol length is reduced by about 1/4 compared to the case of the SCS 15 kHz, when one slot is formed of the same 14 OFDM symbols, The slot length is 1ms, while the 60kHz-based slot length is reduced to about 0.25ms.

As described above, in NR, a method of satisfying the requirements of URLLC and eMBB by defining different SCSs or different TTI lengths is being discussed.

PDCCH

In NR and LTE / LTE-A systems, L1 control information such as DL assignment Downlink Control Information (DCI) and UL Grant DCI is transmitted and received through a PDCCH. A control channel element (CCE) is defined as a resource unit for the transmission of the PDCCH, and in the NR, a control resource set (CORESET), which is a frequency / time resource for the PDCCH transmission, may be set for each terminal. In addition, each CORESET may be configured with one or more search spaces consisting of one or more PDCCH candidates for monitoring the PDCCH. In the NR, the detailed description of the parts described in 3GPP TS 38.211 and TS 38.213 of the PDCCH-related details will be omitted for convenience. However, it may be included in the present disclosure.

Wider bandwidth operations

In case of the existing LTE system, a scalable bandwidth operation for any LTC component carrier (CC) was supported. That is, according to the frequency deployment scenario (deployment scenario) in any LTE carrier to configure a single LTE CC, a minimum bandwidth of 1.4 MHz to 20 MHz could be configured, the normal LTE terminal is one LTE For the CC, a transmit / receive capacity of 20 MHz bandwidth was supported.

However, in the case of NR, the design is made to support NR terminals having different transmit / receive bandwidth capabilities through one wideband NR CC. Likewise, by configuring one or more bandwidth parts (BWP, bandwidth part (s)) composed of bandwidths subdivided for an arbitrary NR CC, flexible (BWP) configuration through different bandwidth part configuration and activation for each UE. It is required to support flexible bandwidth operation (wider bandwidth operation).

In more detail, in NR, one or more bandwidth parts may be configured through one serving cell configured from a UE perspective, and the corresponding UE may include one downlink bandwidth part in a corresponding serving cell. DL bandwidth part and one uplink bandwidth part (UL bandwidth part) by activation (activation) was defined to be used for the transmission and reception of uplink / downlink data. In addition, when a plurality of serving cells are configured in the corresponding UE, that is, even for a UE to which a CA is applied, one downlink bandwidth part and / or uplink bandwidth part is activated for each serving cell. By using the radio resources of the corresponding serving cell (serving cell) has been defined to use for transmitting and receiving uplink / downlink data.

In more detail, an initial bandwidth part is defined for an initial access procedure of a terminal in a serving cell, and one or more terminals are specified through dedicated RRC signaling for each terminal. A specific bandwidth part (s) may be configured, and a default bandwidth part for a fallback operation may be defined for each terminal.

However, in any serving cell, a plurality of downlink and / or uplink bandwidth parts are simultaneously activated and used according to the capability and bandwidth part (s) configuration of the terminal. In NR rel-15, only one downlink bandwidth part and one uplink bandwidth part may be activated at an arbitrary time in an arbitrary terminal in NR rel-15. .

NR-U

In the case of an unlicensed band, unlike a licensed band, any operator or individual can be used to provide a wireless communication service within the regulation of each country, not a wireless channel exclusively used by any operator. Accordingly, when providing NR service through unlicensed band, co-existence problem with various short range wireless communication protocols such as WiFi, Bluetooth, NFC, etc. already provided through the unlicensed band, and also between each NR operator or LTE provider There is a need for a solution to co-existence problems.

Accordingly, when providing an NR service through an unlicensed band, the power level of a radio channel or a carrier to be used is sensed by transmitting a radio signal before transmitting a radio signal to avoid interference or collision between respective radio communication services. There is a need to support a List Before Talk (LBT) based wireless channel access method for determining whether a channel or a carrier is available. In this case, if a specific radio channel or carrier of the unlicensed band is in use by another radio communication protocol or another operator, the radio communication service through the unlicensed band is not licensed band because there is a possibility of being restricted by the provision of NR service through the band. Unlike the wireless communication service through the LAN, the QoS required by the user cannot be guaranteed.

In particular, in the case of NR-U, unlike the existing LTE which always supported unlicensed spectrum through carrier aggregation (CA) with licensed spectrum, deployment scenario of unlicensed band NR As a deployment scenario, an unlicensed band is considered because a stand-alone NR-U cell, a licensed band NR cell, or a dual connectivity (DC) based NR-U cell with an LTE cell is considered. It is necessary to design a data transmission / reception method to satisfy the minimum QoS in itself.

To this end, the present disclosure proposes a method for transmitting an uplink control channel of a terminal in an NR-U cell.

Hereinafter, a method of transmitting HARQ feedback information in an unlicensed band will be described in detail with reference to the accompanying drawings.

10 is a diagram illustrating a procedure of performing wireless communication by a terminal using information on an LBT failure region in an unlicensed band according to an embodiment.

Referring to FIG. 10, the terminal may receive information for allocating radio resources in a system band composed of a plurality of subbands (S1000).

According to an example, assume an environment in which an unlicensed band consists of a plurality of subbands corresponding to 20 MHz, which is a LBT execution unit. For example, a band of 100 MHz consisting of five subbands can be assumed. At least one subband of the plurality of subbands may be configured as a bandwidth part (BWP) of the terminal.

The base station may allocate radio resources to be used for transmitting the downlink signal or channel to the terminal for the bandwidth part of the terminal. The terminal may receive the allocation information for the resource block (RB) in the frequency domain and the allocation information for the transmission start symbol and the duration in the time domain from the base station. According to an example, allocation information for a radio resource may be indicated through downlink control information (DCI).

Referring back to FIG. 10, the terminal may receive information on a failure before talk (LBT) failure region of radio resources (S1010).

According to an example, the base station may transmit information on the LBT failure region to the terminal as a downlink signal or a channel. That is, information about an area where a downlink signal or a channel cannot be transmitted due to LBT failure among the allocated areas simultaneously with signal transmission may be explicitly indicated.

Since the division of the subbands is determined at the time of cell band determination, the number and type of subbands associated with one terminal are determined at the time of setting the BWP for the corresponding terminal. At least one subband of the plurality of subbands constituting the system band may be associated with the BWP of the terminal. In downlink, the base station may perform LBT on at least one subband associated with the BWP of the terminal before starting transmission for the corresponding terminal.

According to an example, the information on the LBT failure area may be indicated through downlink control information (DCI). The information on the LBT failure region may include information indicating whether the LBT succeeds for each of the at least one subbands associated with the BWP of the terminal, that is, each of the subbands included in the radio resource allocated to the terminal among the plurality of subbands. .

In this case, success or failure of LBT for each subband may be transmitted in a bitmap form by giving a field value to downlink control information. In addition, when multiple starting points are supported, starting points that can be transmitted for a subband in which LBT has failed may also be transmitted.

According to an example, the DCI including the information on the LBT failure area may be a DCI delivering the original data transmission area and method. In this case, the corresponding DCI may include LBT success information for the subband along with scheduling information for downlink transmission.

Or, the DCI including the information on the LBT failure area may be defined a new DCI format to deliver information about the LBT failure area. In this case, the corresponding DCI may not include scheduling information for downlink transmission, but may include information on whether LBT succeeds for the subband. In this case, the length of the message may be fixed to the number of subbands associated with the BWP allocated to each terminal, the number of subbands associated with the entire carrier band, or fixed to a specific value.

According to an example, subbands and bits may be mapped one-to-one in a bitmap. Alternatively, when the number of bits is larger than the number of subbands, the remaining bits may be padded to the length or set and then padded with the remaining bits, or repeated valid bits may be filled. Alternatively, when the number of bits is smaller than the number of subbands, two or more subbands may be mapped to one bit. In this case, the number of subbands corresponding to one bit may be all set the same, or may be set differently according to the number of bits and the number of subbands.

For example, when the number of bits is 5 and the number of subbands is 8, the first 3 bits may be mapped to two subbands, and the remaining two bits may be mapped to one subband each. As such, when a plurality of subbands are indicated together, when the LBT fails for only one subband, it may be determined as an LBT failure for all subbands. Alternatively, when the LBT fails for all subbands, it may be determined as an LBT failure for all subbands. Alternatively, when the LBT fails more than a predetermined ratio among the plurality of subbands, it may be determined as an LBT failure for all subbands.

The DCI may be transmitted every time a downlink signal or channel is transmitted, or may be transmitted only when there is a failed subband. In addition, the DCI may be scrambled with an RNTI associated with a specific terminal and configured to receive only a specific terminal. Alternatively, the DCI may be configured to be scrambled with RNTIs associated with a plurality of terminals so that all terminals that can access the control resource set (CORESET) can receive them. That is, the terminal may receive a DCI including information on the LBT failure region through a UE group common physical downlink control channel (PDCCH).

According to an example, a new DCI format 2-1u similar to the DCI format 2-1 defined for the pre-emption indication may be defined. In this case, like the preemption indication field, the information field for the subband LBT failure region may be included in the payload and scrambled by INT-RNTI (Interrupted transmission indication RNTI) like the DCI format 2-1.

Alternatively, a separate new RNTI may be defined for use in DCI including information on the LBT failure region for the subband without using the INT-RNTI. According to an example, the newly defined RNTI may be referred to as occupied subband indication RNTI (Occupied subband indication RNTI). However, this is not an example and is not limited to the corresponding name, and the newly defined RNTI may be referred to as another name.

The newly defined occupied subband indication RNTI may be pre-assigned for UE groups using an unlicensed band composed of a plurality of subbands. The CRC bit of the DCI including information on the LBT failure region for the subband may be scrambled with the occupied subband indication RNTI and transmitted through the PDCCH. Each terminal of the UE group may receive the DCI through the corresponding PDCCH, and check the CRC of the DCI by using the occupied subband indication RNTI. Accordingly, as described above, all terminals that can access the corresponding CORESET can receive information on the LBT failure area, and in this case, the PDCCH used may be defined as a group common PDCCH (GC-PDCCH).

Referring back to FIG. 10, the UE may monitor a downlink signal in a region excluding the LBT failure region in a radio resource (S1020) and receive a downlink signal in a corresponding region (S1030).

The terminal may monitor the downlink signal based on the allocation information for the radio resource and the information on the LBT failure area. That is, the UE may check the remaining subbands except for the subband in which the LBT has failed among the plurality of subbands constituting the radio resource allocated to the reception of the downlink signal. The terminal may receive a downlink signal from the base station through the remaining subbands.

According to an example, when multiple starting points are supported in the unlicensed band, the LBT may be performed again for the subband in which the LBT fails during the transmission of the downlink signal. When the LBT succeeds for the subband in which the LBT has failed, the UE may receive information on the LBT success and transmission start point for the corresponding subband through the DCI. Accordingly, the terminal may receive a downlink signal by monitoring a subband in which LBT succeeds during downlink transmission after the corresponding transmission start point.

According to this, when resource allocation is performed over a plurality of subbands in an unlicensed band, wireless communication can be efficiently performed when some of the subbands of the corresponding resource are not available. In addition, by transmitting information on the LBT failure area, which is a subband in an unavailable state, wireless communication can be efficiently performed even when some of the subbands of the corresponding resource are not available.

FIG. 11 is a diagram illustrating a procedure in which a base station performs wireless communication using information on an LBT failure area in an unlicensed band according to an embodiment.

Referring to FIG. 11, the base station may perform listen before talk (LBT) for each subband in a system band composed of a plurality of subbands (S1100).

According to an example, assume an environment in which an unlicensed band consists of a plurality of subbands corresponding to 20 MHz, which is a LBT execution unit. For example, a band of 100 MHz consisting of five subbands can be assumed. At least one subband of the plurality of subbands may be configured as a BWP of the terminal.

The base station may perform an LBT process for checking whether the corresponding radio channel is occupied by another node in order to transmit the radio signal through the unlicensed band. That is, the base station may perform LBT for at least one subband configured with the BWP of the terminal in order to transmit a downlink signal or channel to any terminal in the unlicensed band. As a result of performing LBT, when the subband of the corresponding unlicensed band is not occupied, the base station may transmit a PDCCH and a corresponding PDSCH to the terminal.

Referring back to FIG. 11, the base station may transmit information for allocating radio resources in the system band (S1110).

The base station may allocate radio resources to be used for transmitting the downlink signal or channel to the terminal for the bandwidth part of the terminal. The base station may transmit the allocation information for the resource block (RB) in the frequency domain and the transmission start symbol and the duration information in the time domain to the terminal. According to an example, allocation information for a radio resource may be indicated through downlink control information (DCI).

Referring back to FIG. 11, the base station may transmit information on the LBT failure area of the radio resource (S1120).

According to an example, the base station may transmit information on the LBT failure area to the terminal when transmitting a downlink signal or a channel. That is, the base station may explicitly indicate information about an area in which the downlink signal or channel cannot be transmitted due to the LBT failure among the allocated areas simultaneously with signal transmission.

According to an example, the information on the LBT failure area may be indicated through downlink control information (DCI). The information on the LBT failure region may include information indicating whether the LBT succeeds for each of the at least one subbands associated with the BWP of the terminal, that is, each of the subbands included in the radio resource allocated to the terminal among the plurality of subbands. .

In this case, success or failure of LBT for each subband may be transmitted in a bitmap form by giving a field value to downlink control information. In addition, when multiple starting points are supported, starting points that can be transmitted for a subband in which LBT has failed may also be transmitted.

According to an example, the DCI including the information on the LBT failure area may be a DCI delivering the original data transmission area and method. In this case, the corresponding DCI may include LBT success information for the subband along with scheduling information for downlink transmission.

Or, the DCI including the information on the LBT failure area may be defined a new DCI format to deliver information about the LBT failure area. In this case, the corresponding DCI may not include scheduling information for downlink transmission, but may include information on whether LBT succeeds for the subband. In this case, the length of the message may be fixed to the number of subbands associated with the BWP allocated to each terminal, the number of subbands associated with the entire carrier band, or fixed to a specific value.

According to an example, subbands and bits may be mapped one-to-one in a bitmap. Alternatively, when the number of bits is larger than the number of subbands, the remaining bits may be padded to the length or set and then padded with the remaining bits, or repeated valid bits may be filled. Alternatively, when the number of bits is smaller than the number of subbands, two or more subbands may be mapped to one bit. In this case, the number of subbands corresponding to one bit may be all set the same, or may be set differently according to the number of bits and the number of subbands.

For example, when the number of bits is 5 and the number of subbands is 8, the first 3 bits may be mapped to two subbands, and the remaining two bits may be mapped to one subband each. As such, when a plurality of subbands are indicated together, when the LBT fails for only one subband, it may be determined as an LBT failure for all subbands. Alternatively, when the LBT fails for all subbands, it may be determined as an LBT failure for all subbands. Alternatively, when the LBT fails more than a predetermined ratio among the plurality of subbands, it may be determined as an LBT failure for all subbands.

The DCI may be transmitted every time a downlink signal or channel is transmitted, or may be transmitted only when there is a failed subband. In addition, the DCI may be scrambled with an RNTI associated with a specific terminal and configured to receive only a specific terminal. Alternatively, the DCI may be configured to be scrambled with RNTIs associated with a plurality of terminals so that all terminals that can access the control resource set (CORESET) can receive them. That is, the base station may transmit a DCI including information on the LBT failure area through a UE group common physical downlink control channel (PDCCH).

According to an example, a new DCI format 2-1u similar to the DCI format 2-1 defined for the pre-emption indication may be defined. In this case, like the preemption indication field, the information field for the subband LBT failure region may be included in the payload, and may be scrambled by INT-RNTI like DCI format 2-1 and transmitted.

Alternatively, a separate new RNTI may be defined for use in DCI including information on the LBT failure region for the subband without using the INT-RNTI. According to an example, the newly defined RNTI may be referred to as occupied subband indication RNTI (Occupied subband indication RNTI). However, this is not an example and is not limited to the corresponding name, and the newly defined RNTI may be referred to as another name.

The newly defined occupied subband indication RNTI may be pre-assigned for UE groups using an unlicensed band composed of a plurality of subbands. The CRC bit of the DCI including information on the LBT failure region for the subband may be scrambled with the occupied subband indication RNTI and transmitted through the PDCCH. Each terminal of the UE group may receive the DCI through the corresponding PDCCH, and check the CRC of the DCI by using the occupied subband indication RNTI. Accordingly, as described above, all terminals that can access the corresponding CORESET can receive information on the LBT failure area, and in this case, the PDCCH used may be defined as a group common PDCCH (GC-PDCCH).

Referring back to FIG. 11, the base station may transmit a downlink signal in a region excluding the LBT failure region in the radio resource (S1130).

The base station may transmit a downlink signal to the terminal based on the allocation information for the radio resource and the information on the LBT failure area. That is, the base station can identify the remaining subbands except the subbands for which the LBT has failed among the plurality of subbands constituting the radio resource allocated to the reception of the downlink signal. The base station may transmit a downlink signal to the terminal through the remaining subbands.

According to an example, when multiple starting points are supported in the unlicensed band, the base station may perform LBT again on a subband in which LBT fails during transmission of a downlink signal. If the LBT succeeds for the subband in which the LBT has failed, the base station may transmit information on the LBT success and transmission start point for the corresponding subband to the terminal through the DCI. Accordingly, the terminal may receive a downlink signal by monitoring a subband in which LBT succeeds during downlink transmission after the corresponding transmission start point.

According to this, when resource allocation is performed over a plurality of subbands in an unlicensed band, wireless communication can be efficiently performed when some of the subbands of the corresponding resource are not available. In addition, by transmitting information on the LBT failure area, which is a subband in an unavailable state, wireless communication can be efficiently performed even when some of the subbands of the corresponding resource are not available.

Hereinafter, with reference to the relevant drawings, each embodiment of performing wireless communication in consideration of the LBT failure area in the unlicensed band (unlicensed band) in NR will be described in detail.

In order to transmit a radio signal from any node in the unlicensed band, it is required to go through a List Before Talk (LBT) process to check whether the corresponding radio channel is occupied by another node.

Accordingly, in order to transmit PDSCH for an arbitrary UE in an NR-U cell of an unlicensed band configured by an arbitrary NR base station, the base station must perform LBT for the corresponding unlicensed band. As a result of performing LBT, when the radio channel of the corresponding unlicensed band is empty, the base station may transmit a PDCCH and a corresponding PDSCH to the terminal.

Similarly, in order to transmit an uplink signal in the unlicensed band, the terminal also needs to perform LBT on the unlicensed band before transmitting the uplink signal.

12 illustrates an example of performing LBT for wireless communication in an unlicensed band according to an embodiment.

According to an example, when allocating PUCCH transmission resources for an arbitrary terminal or when allocating PUSCH transmission resources, at a corresponding PUCCH or PUSCH transmission time, the base station may indicate whether to perform LBT on the corresponding terminal. The UE may transmit uplink control information (UCI) such as HARQ ACK / NACK feedback information or CQI / CSI reporting information to the base station through the PUCCH. In this regard, in the NR, a time resource and a frequency resource, which are PUCCH resources for transmitting HARQ feedback, may be indicated by a base station through a DL assignment DCI. Alternatively, the PUCCH resource for transmitting HARQ feedback may be set to semi-static through RRC signaling. In particular, in the case of time resources, a K1 value, which is a timing gap value between a PDSCH reception slot and a corresponding HARQ feedback information transmission slot, may be transmitted to a terminal through DL assignment DCI or RRC signaling.

PUCCH resources for CQI / CSI reporting may also be allocated through RRC signaling and DL assignment DCI.

Referring to FIG. 12, the LBT (DL LBT) for downlink transmission is successful in the base station, and it is indicated by hatching that downlink transmission is performed through the unlicensed band at a later time. According to an example, the downlink transmission may be a transmission of a downlink channel or a signal indicating uplink transmission. For example, a PUCCH for PDSCH transmission and a corresponding HARQ feedback, a DCI requiring CQI / CSI reporting, a PUCCH for reporting accordingly, or a DCI for transmitting scheduling information for a PUSCH and a corresponding PUSCH, etc. Can be. In this case, a timing gap occurs between downlink transmission and uplink transmission.

For example, when a downlink signal or channel according to downlink transmission indicates PUCCH transmission in an NR-U cell that is an unlicensed band, the UE basically transmits the corresponding PUCCH according to regulation of an unlicensed spectrum. LBT must be performed first, and whether to transmit PUCCH at the indicated time point is determined according to the LBT result. If, as a result of the LBT, the corresponding radio channel is occupied by another node, that is, when an LBT failure occurs, the corresponding UE may not perform PUCCH transmission at the indicated time.

However, a DLSCH assignment slot including a PUCCH resource allocation information and PUCCH transmission indication information or a PDSCH transmission slot according to a corresponding DL assignment DCI and a corresponding PUCCH transmission slot are corresponding base stations. If the UE belongs to the Channel Occupancy Time (COT) of the UE, PUCCH transmission may be possible in the corresponding UE without performing LBT. This is because the base station is already occupied for downlink transmission to the corresponding UE in the unlicensed band and is not occupied by another node. That is, depending on the COT of the base station and the setting of the K1 value, the HARQ feedback transmission through the PUCCH may be possible in the corresponding terminal without the LBT.

Similarly, when CSI / CQI reporting through PUCCH is indicated through DL assignment DCI, a slot in which DL assignment DCI is transmitted and CQI / CSI reporting accordingly If a timing gap value between slots in which PUCCH transmission including reporting information is made is M, CSI / CQI reporting through PUCCH without LBT in the corresponding UE according to the corresponding timing gap value M and the COT of the base station. This may be possible.

In addition, similar to the case of the PUCCH, the K2 value, which is timing gap information between the UL grant DCI transmitted by the base station and the slot in which the PUSCH is transmitted, is also used for the PUSCH transmission of the UE. May be set to semi-static through RRC signaling or may be set to dynamic through UL grant DCI (UL grant DCI). Even in this case, when an uplink grant DCI (UL grant DCI) transmission slot including corresponding PUSCH transmission resource allocation information and a corresponding PUSCH transmission slot belong to within a COT (Channel Occupancy Time) of the base station, the UE does not perform the LBT without performing the PUSCH. Transmission may be possible.

In this regard, according to an embodiment of the present disclosure, the base station may instruct the terminal by setting an LBT scheme for performing LBT when PUCCH or PUSHC transmission from any terminal. According to an example, the LBT scheme may be divided into a plurality of schemes by at least one of whether to perform LBT, random back off, and random back off time. In the present disclosure, a method of performing LBT is referred to as an 'LBT method', but is not limited thereto. The manner of performing the LBT may be variously referred to as the LBT category.

According to an embodiment, the LBT method is a first LBT method that does not perform LBT, a second LBT method that performs LBT but does not perform random backoff, performs a random backoff with the LBT, but the random backoff time interval is fixed. The third LBT scheme and the random backoff with the LBT may be performed, but the random backoff time interval may include a fourth LBT scheme and the like.

According to an example, the BS may be defined to directly indicate whether to perform LBT for uplink transmission of the UE through L1 control signaling. In more detail, it may be defined to include a corresponding LBT indication information region in a DL assignment DCI format for transmitting PDSCH scheduling control information.

For example, the LBT indication information may be indication information of 1 bit. In this case, when PUCCH transmission of a UE corresponding to a corresponding DL assignment DCI format (DL assignment DCI format) is determined according to the value (0, 1) of the corresponding bit, it may be defined to determine whether to perform LBT on the corresponding UE. have. That is, in this case, the value of the corresponding bit may mean that the first LBT scheme and the remaining LBT schemes are distinguished from the aforementioned LBT schemes.

According to another example, the corresponding LBT indication information may be two bits of indication information. In this case, when transmitting the PUCCH of the terminal corresponding to the DL assignment DCI format (DL assignment DCI format) according to the value of the corresponding bit (00, 01, 10, 11), the LBT scheme for performing the LBT in the terminal Can be defined to be determined. That is, in this case, the value of the corresponding bit may mean that the first LBT scheme and the fourth LBT scheme are distinguished from the aforementioned LBT scheme.

In this case, the PUCCH transmission of the terminal corresponding to the DL assignment DCI format described above is transmitted to the HARQ feedback information of the terminal according to the PDSCH reception of the terminal based on the DL assignment DCI format. It may be a PUCCH transmission for. Alternatively, in another case of PUCCH transmission of a UE corresponding to a DL assignment DCI format, CQI / CSI reporting is triggered by a corresponding DL assignment DCI format. ), It may be a PUCCH transmission for CQI / CSI reporting accordingly.

Similarly, the UL grant DCI format (UL grant DCI format) for transmitting PUSCH scheduling control information may be defined to include a corresponding LBT indication information (LBT indication information) region.

For example, the LBT indication information may be indication information of 1 bit. In this case, according to the value (0, 1) of the corresponding bit, when the PUSCH transmission of the terminal corresponding to the UL grant DCI format (UL grant DCI format), it can be defined to determine whether to perform the LBT in the terminal. have. That is, in this case, the value of the corresponding bit may mean to distinguish the first scheme from the other schemes among the aforementioned LBT schemes.

According to another example, the corresponding LBT indication information may be two bits of indication information. In this case, when the PUSCH of the UE corresponding to the UL grant DCI format (UL grant DCI format) according to the value of the corresponding bit (00, 01, 10, 11), the LBT scheme for performing the LBT in the UE Can be defined to be determined. That is, in this case, the value of the corresponding bit may mean that the first to fourth schemes are distinguished from the aforementioned LBT schemes.

However, the PUSCH transmission of the terminal corresponding to the UL grant DCI format may be a PUSCH transmission for uplink data transmission of the terminal or a PUSCH transmission for UCI transmission of the terminal.

As another embodiment of defining whether to perform LBT for the uplink transmission or the LBT scheme in the terminal, whether to perform the LBT is shown in FIG. 12, downlink transmission indicated by the corresponding uplink transmission and accordingly uplink It may be defined to be determined by a timing gap value between transmissions.

According to an example, when a timing gap value is smaller than a certain threshold value, respectively, the UE may define that the indicated PUCCH or PUSCH transmission is possible without LBT. Alternatively, if a timing gap value is larger than a corresponding threshold, it may be defined so that the UE can perform a corresponding PUCCH or PUSCH transmission after performing LBT.

According to an example, the threshold is determined by the COT value in the corresponding NR-U, or accordingly cell-specific RRC signaling or UE-specific RRC signaling by the base station It may be configured through specific RRC signaling, or may be configured through cell-specific RRC signaling or UE-specific RRC signaling by a base station regardless of a COT.

In addition, the corresponding threshold is defined as a single threshold for each uplink transmission case or as a different threshold to be used for cell-specific RRC signaling by the base station. It may be configured through specific RRC signaling or UE-specific RRC signaling.

Accordingly, the LBT scheme to be performed to transmit the uplink signal in the unlicensed band can be determined, and the uplink signal can be transmitted in the unlicensed band according to the determined LBT scheme.

The present disclosure provides a transmission allocation and control method when a channel availability situation is independent of a transceiver's intention in a 3GPP NR system. In particular, the present invention provides a method for transmitting a large packet in an NR-based access to unlicensed spectrum (NR-U) system environment using a common channel as a transmission space.

In the conventional 3GPP LTE, one of the methods using an unlicensed band, a control channel is operated through a licensed band, which is a band exclusively operated by a communication manager, and a data channel is an unlicensed band, which is a band that can be occupied / used by any user. We have proposed a LAA system that can be operated through. In addition, studies are being conducted to introduce NR-U systems as new features that can perform transmission and reception in unlicensed bands in NR.

As mentioned above, the unlicensed band is generally listened to through a process called List-Before-Talk (LBT) to check whether there is another device occupying the channel band to transmit, and then the communication is performed only when the band is empty. May be initiated. In this case, since performing the LBT process for all frequency components is inefficient, generally, the occupancy status of the corresponding band is investigated in units of 20 MHz and communication is performed within the corresponding bandwidth.

In the case of downlink, the base station, which is the transmitting end, does not need to allocate resources when the channel is not empty. On the contrary, in an uplink environment, a terminal that is a transmitting end may not be able to transmit to an allocated resource region according to an LBT failure of a resource allocated by a base station that is a receiving end. When such a transmission failure occurs, it is generally assumed to be a reception failure of a base station, and processed in the form of performing retransmission, and a specific block which can improve performance such as not including the block in soft combine when decoding is included. Methods were discussed.

However, NR assumes scenarios that use a band larger than 20 MHz, which is an LBT unit, and thus methods for operating in a band above 20 MHz are also discussed in NR-U. In this case, a plurality of LBT sections divided by 20 MHz units exist, and thus, each of the plurality of LBT sections may be divided into subbands or subbands within one band.

As described above, since the LAA applied to 3GPP LTE has the same channel bandwidth and LBT unit, only the entire channel can be used. However, as in NR, in a band wider than 20 MHz, a plurality of LBT sections, that is, a plurality of subbands, exist, and availability may vary in each section. Even if the LBT fails in some areas, that is, even if the channel is not available in some areas, the UE can secure a band that can be used during transmission and reception, which is a band in which the LBT is successful. As such, when the LBT fails in some areas, there is no consensus on how to use the remaining bands for the successful transmission of the LBT.

In this regard, a method mainly discussed is a method of allocating uplink / downlink scheduling for each subband. This is a method of performing NR transmission and reception itself in units of 20 MHz, and merging them in the upper stage similarly to CA (carrier aggregation) to perform transmission and reception. Due to the difference in resource allocation to a plurality of subbands using only one control channel, the actual technology is closer to a multiple scheduling method. However, since this method must operate one transport block within 20 MHz unconditionally, there may be a significant limitation in large transmission, especially in an environment using high numerology.

Hereinafter, the present disclosure provides an efficient transmission method when resource allocation is performed over a plurality of subbands in an NR-U environment, and some subbands of allocated resources are not available. In particular, the receiver can distinguish transmission failures due to noise and transmission failures due to LBT failures, and provide information on LBT failure areas to the receivers so as to derive higher decoding performance by providing accurate reliability of information during subsequent decoding. Provide a way to do it. In addition, the present invention provides a method for configuring a transport block in consideration of the LBT failure area under the assumption that information on the LBT failure area is transmitted.

The present disclosure provides a method of delivering an LBT failure area upon transmission, a method of delivering an LBT failure area upon retransmission, and a method of setting a transport block according to the LBT failure area. The terms used in the present disclosure may be replaced with other terms having substantially the same meaning later, and for the convenience of description, the scope of the technology is not limited by the terms used.

13 illustrates a subband of an unlicensed band according to an embodiment. 14 is a diagram for describing a transmission area for a case where multiple starting points are supported in an unlicensed band according to an embodiment. 15 and 16 are diagrams for describing a DCI format (DCI format) including information on an LBT failure area, according to an embodiment.

As shown in FIG. 13, it is assumed that the system band is composed of a plurality of subbands that are LBT execution units. For example, a band of 100 MHz consisting of five subbands can be assumed. It is assumed that the corresponding band is composed of c resource blocks (RBs) represented by numbers 1 to c, and the bands a to b are composed of a bandwidth part (BWP) of the terminal. In addition, it is assumed that the numbers of the RBs in which the partitions dividing each subband exist are s, t, u, and v from below. In this case, as shown in FIG. 13, it is assumed that 1 <s ≦ a <t <u <b ≦ v <c is established. In FIG. 13, all of the values of s and a, b, and v are shown in different cases. However, the present invention is not limited thereto. The values of s and a, b, and v may each be equal.

In FIG. 13, for example, one slot having a length of 7 is illustrated, and in NR, a time length defined as one slot is used as a scheduling unit. When a resource is allocated, a specific start point and a length are indicated by a control message. For example, in FIG. 13, when one slot is used up, a start point 1 and a length 7 are indicated by a control message. In this case, available start point and length pairs can be predefined to reduce the size of the control message. In addition, depending on the success or failure of the LBT in the unlicensed band, it may be possible to support the indication of a more diverse starting point and length in consideration of the case that the use of the band from the middle.

The configuration of the system band and subbands shown in FIG. 13 and the configuration of the BWP of the terminal are just examples for convenience of description and the present invention is not limited thereto. Naturally, the number of RBs of a system band, the number of subbands, the number of configuration RBs, or the BWP of a terminal may be set differently in some cases.

According to an example, in the present disclosure, each scenario may be assumed as well as a predetermined starting point and length, as well as a situation in which a different starting point and length than other blocks allocated together are supported. For example, referring to FIG. 14, a case where a radio resource allocated for a terminal is indicated by the DCI is illustrated. The DCI may indicate a start symbol in the time domain and resource blocks (RBs) in the frequency domain as a transmission region. Assume that LBT has failed for a subband composed of four RBs in the frequency domain. In this case, if the LBT is successful from the fifth symbol for the corresponding subband, the fifth symbol for the corresponding subband may be transmitted to the terminal as a start point of downlink transmission.

Hereinafter, specific embodiments according to the present disclosure will be described on the assumption of the transmission area and the foregoing description with reference to FIG. 14.

According to the first embodiment, the transmitter may transmit information on the LBT failure area when transmitting a signal. In this case, information about an area that cannot be transmitted due to an LBT failure among the areas allocated at the same time as the signal transmission at the transmitting end may be explicitly or implicitly delivered. Hereinafter, the description is divided into a downlink and an uplink environment, and the description is divided into a method of explicitly or implicitly delivering it again. The methods are independent of each other and can be selectively applied as needed.

According to an example, in the case of downlink transmission, information on the LBT failure region may be explicitly indicated. Since the division of subbands is determined at the time of cell band determination, the number and type of subbands associated with one UE are determined at the time of BWP configuration. For example, in FIG. 13, three subbands (subbands 2 to 4) are associated with the BWP of the terminal. In downlink, the base station may perform LBT for the three subbands before starting transmission for the corresponding UE. In this case, success or failure of LBT for each subband may be transmitted in a bitmap form by giving a field value to downlink control information (DCI). In addition, when multiple starting points are supported, starting points that can be transmitted for a subband in which LBT has failed may also be transmitted.

In this case, the DCI including the information on the LBT failure area may be a DCI delivering an initial data transmission area and a method. In this case, referring to FIG. 15, the corresponding DCI may include LBT success information for the subband along with scheduling information for downlink transmission. However, FIG. 15 is an example and the present invention is not limited thereto. The location or name of the field including the LBT success information about the subband may be set differently.

Alternatively, the DCI including the information on the LBT failure area may be another DCI in a new format transmitted at a location associated with the corresponding data transmission location. In this case, referring to FIG. 16, the corresponding DCI may include information on whether LBT succeeds for a subband without scheduling information for downlink transmission. However, FIG. 16 is an example and the present invention is not limited thereto, and a location or name of a field including LBT success information about a subband may be set differently.

The transmission of information on whether the LBT succeeds for each subband may be specifically performed as follows. According to an example, a new DCI format including subband based LBT success information may be defined. In this case, the length of the message may be fixed to the number of subbands associated with the BWP allocated to each terminal, the number of subbands associated with the entire carrier band, or fixed to a specific value.

Accordingly, the subband to bit mapping in the bitmap may be a one-to-one mapping between the subband and the bit. Alternatively, when the number of bits is greater than the number of subbands, the remaining bits may be padded to the length, or may be padded with the remaining bits, or the valid bits may be repeatedly filled. Alternatively, when the number of bits is smaller than the number of subbands, two or more subbands may be bundled and mapped. In this case, the number of subbands corresponding to one bit may be all set the same, or the difference may be set according to the number of bits and the number of subbands.

For example, when the number of bits is 5 and the number of subbands is 8, the first 3 bits may map two subbands in a bundle, and the remaining 2 bits may map only one subband. As such, when a plurality of subbands are indicated together, when the LBT fails for only one subband, it may be determined as an LBT failure for all subbands. Alternatively, when the LBT fails for all subbands, it may be determined as an LBT failure for all subbands. Alternatively, when the LBT fails over a predetermined ratio among the plurality of subbands, it may be determined as an LBT failure for all the subbands.

The DCI may be transmitted at every transmission or may be transmitted only when there is a failed subband. In addition, the DCI may be scrambled with an RNTI associated with a specific terminal and configured to receive only a specific terminal. Alternatively, the DCI may be configured to be scrambled with RNTIs associated with a plurality of terminals so that all terminals that can access the control resource set (CORESET) can receive them.

As a specific example, a new DCI format 2-1u similar to the DCI format 2-1 defined for the pre-emption indication may be defined. In this case, like the preemption indication field, the information field for the subband LBT failure region may be included in the payload, and may be scrambled by INT-RNTI like DCI format 2-1 and transmitted.

Alternatively, a separate new RNTI may be defined for use in DCI including information on the LBT failure region for the subband without using the INT-RNTI. According to an example, the newly defined RNTI may be referred to as occupied subband indication RNTI (Occupied subband indication RNTI). However, this is not an example and is not limited to the corresponding name, and the newly defined RNTI may be referred to as another name.

The newly defined occupied subband indication RNTI may be pre-assigned for UE groups using an unlicensed band composed of a plurality of subbands. The CRC bit of the DCI including information on the LBT failure region for the subband may be scrambled to the occupied subband indication RNTI and transmitted through the PDCCH. Each terminal of the UE group may receive the DCI through the corresponding PDCCH, and check the CRC of the DCI by using the occupied subband indication RNTI. Accordingly, as described above, all terminals that can access the corresponding CORESET can receive information on the LBT failure area, and in this case, the PDCCH used may be defined as a group common PDCCH (GC-PDCCH).

According to another example, in the case of downlink transmission, information on the LBT failure region may be implicitly indicated. For example, a reference signal such as DMRS may be used to indicate the LBT failed subband without changing the existing DCI format. To this end, existing DMRS may be utilized, CSI-RS may be utilized, or a new reference signal may be used.

In the case of using the reference signal, the receiving end may determine that transmission is not performed even if the corresponding subband is an area allocated by the DCI when the detection value of the reference signal in a specific subband is less than or equal to a predetermined threshold. Alternatively, the reference signal of the transmission region may be changed for higher detection reliability. For example, the reference signal carried on the subband after the failed LBT may have the number of previously failed subbands as a parameter.

For example, it is assumed that the environment in which the reference signal J is transmitted in subband 10 in order, such as the reference signal A in subband 1, the reference signal B in subband 2, and so on. When subbands 3, 4, 5, and 9 of the subbands 1 to 10 fail LBT, reference signals A and B may be allocated to subbands 1 and 2 as they are, and reference signals C may be transmitted to subband 6. . Subbands 7 and 8 may be allocated with D and E, or G and H may be allocated as originally, and subband 10 may be allocated with F or I accordingly. Since the reference signal C is transmitted instead of the reference signal F in the subband 6, the receiver may determine that the LBT failure for the subbands 3, 4, and 5 has occurred.

In addition, when the temporal position of the reference signal, such as the front-loaded DMRS, may mean the start point of the transmission region, the position of the reference signal may be determined as the transmission start point. Accordingly, a temporal position at which transmission is newly started can be transmitted in a subband in which LBT has failed using a reference signal such as a front-loaded DMRS. This is applied at the same time as explicitly indicating the information on the LBT failure area described above, thereby reducing the complexity by performing blind detection of the reference signal only on the LBT failure area.

According to another example, in the case of uplink transmission, information on the LBT failure region may be explicitly indicated. For example, as in the case of the downlink transmission described above, the information on the LBT failure region may be transmitted in the form of a bitmap using a field in uplink control information (UCI) transmitted through the PUSCH. . However, since UCI in PUSCH is piggybacked in a transport block, information that cannot be obtained when the transport block fails to be decoded. In general, when the unexpected shortage of transport space occurs, the transport block itself is not decoded properly. You are very unlikely.

Therefore, even if any LBT failure occurs near the uplink transport block, a PUCCH resource that can be sufficiently decoded can be set at a predetermined position, and the LBT failure and a new transmission start point according to the PUCCH can be transmitted. For example, the last OFDM symbol among the uplink transmission resources may be set as a PUCCH space for transmitting the LBT failure as a bitmap, and the LBT failure may be transmitted through the space. At this time, each PUCCH is repeatedly transmitted for each subband, so that the receiving end can know whether the LBT is successful for all subbands even if only the PUCCH in one subband is received.

According to another example, in the case of uplink transmission, information on the LBT failure region may be implicitly indicated. In this case, as in the case of downlink transmission, subband information in which the LBT implicitly fails may be transmitted using an uplink DMRS or another predetermined RS.

According to the second embodiment, the transmitter may transmit information on the LBT failure area when retransmitting.

In this case, information related to an area that could not be transmitted due to an LBT failure among the areas allocated by the transmitting end may be transmitted at the time of retransmission. Like the first embodiment, this case may also be considered in downlink and uplink, respectively. In case of retransmission, especially if additional start position is supported at the same time as LBT success information, corresponding information may be transmitted together.

According to an example, in case of downlink transmission, since there is no DCI-related time constraint at the time of retransmission, information related to the LBT failure region may be transmitted in various forms. Accordingly, all the methods proposed in the downlink transmission of the first embodiment can be used. In this case, the difference from the first embodiment is whether the transmission time of the information is the transmission reference or the retransmission reference. In addition, after configuring the CodeBlock Group (CBG) in alignment with the subbands, the CBG flushing out information (CBGFI) is the same as when pre-emption occurs. Implicitly) in a method of indicating flushing with respect to the associated block.

According to another example, in case of uplink transmission, in retransmission, in addition to the method of the first embodiment, related information may be included in the UCI of the PUSCH. In particular, information delivery such as a starting point may be performed while it is difficult to deliver to UCI.

According to the third embodiment, the transport block may be set according to the LBT failure area.

Basically, the subband is an external specification not a range that can be arbitrarily set by the base station, and the subcarrier unit supported by the NR is not an abbreviation of 20 MHz. Thus, the number of RBs involved in one subband range is not always constant and does not match the start and end range of the frame. In addition, when the corresponding subband corresponding to the LBT failure is being used by another node, the transmitting end should perform the transmission considering the guardband of the adjacent subband.

For example, when subband 3 is in use in FIG. 13, the terminal may allocate only a region from a to t-g and u + g to b for transmission with respect to a predetermined value g. In this case, the g value may vary depending on the subcarrier unit or reference frequency range in use, and is generally specified and specified in a standard or collectively transmitted to the terminal through cell-specific RRC signaling. Can be. In any case, at the time of performing the transmission, the base station and the terminal can accurately recognize the range of RBs that should or should not be used for transmission when the LBT of a specific subband fails. LBT failure information can be interpreted.

In this case, the guard band may be configured in an RB unit or may be a resource element (RE) unit in the RB. This environment may also be standardized or determined by the base station according to the configuration of the BWP. In particular, when the bandwidth loss due to the RB unit guardband setting is large, such as when a high subcarrier unit is set, the guardband setting may be determined in RE units.

When the guard band is set in the RB unit or the RE unit, the boundary determined as a result of the LBT may not coincide with the scheduling unit. That is, a case may occur in which scheduling cannot be performed according to a range to be transmitted exactly due to an LBT failure. In particular, this restriction can have a significant effect on a wide bandwidth in which the size of P, which is the size of the RB group (RBG), increases. In the NR, a maximum P of 16 or more may be set, and in case of maintaining an existing scheduling unit in an RA type-0 environment in which bitmap operations are performed in units of P, 15 or more RBs may not be scheduled. do. Meanwhile, in case of RA type-1, which is expressed in a continuous unit and supports scheduling in one RB unit, for example, when subband 3 fails LBT in the BWP of FIG. 13, to schedule the remaining bands by RA type-1, A situation may arise in which the entire band above or below subband 3 needs to be abandoned and scheduled.

If information about LBT failure can be delivered in advance, the following process can be introduced to solve this problem. According to an example, scheduling is performed as is, but may be freely performed without excluding an area that cannot be transmitted due to an LBT failure from the scheduling area. For example, even if the LBT of subband 3 in the above example fails, the base station can still schedule all of the areas from a to b. In addition, if the LBT failure information is delivered at the same time, the terminal can recognize that the corresponding transmission area is a to tg and u + g to b instead of a to b, and can determine that resources are allocated only in the corresponding RB. . Therefore, the transmitting end may generate a transport block in advance in an area except for the LBT failure area.

However, since the limitation of the transmission area due to LBT and LBT failure is made immediately, processing time such as calculation of the actual transmission area and transport block size or MCS determination based on the result may not be sufficiently secured. Accordingly, the transport block generation itself may be performed in advance, and a signal to be transmitted in the LBT failure region may be punctured and transmitted. The two transmission methods described above may be selectively applied in the same situation, and a method of instructing in advance which method is selected or selecting and transmitting the same is required.

Hereinafter, as illustrated in FIG. 13, it is assumed that subbands 2 and 4 succeed in LBT and subband 3 fails in LBT.

According to an example, a transport block may be generated according to an area excluding an LBT failure area in a downlink environment. The PDSCH may be configured with an RB having a size of (t-g-a + 1) + (b-u-g + 1) in consideration of the guardband, except for subband 3 in which the LBT fails in the BWP configured in the terminal. Accordingly, a transport block is generated according to the size of a corresponding transport area, and the generated transport block is mapped to RB resources of a to tg and u + g to b, which are transmission resources except for a frequency domain that cannot be transmitted due to an LBT failure. do. The transmitting end may schedule in a range that includes the entire area to be actually transmitted, and may also transmit information on whether the subband LBT is successful. The receiving end may perform decoding by extracting a transmission region from a to t-g and u + g to b into the RB range where actual transmission is performed.

According to another example, the LBT failure region may be punctured and transmitted in a downlink environment. The PDSCH is composed of b-a + 1 RBs, which are originally BWP sizes, and a transport block may be generated according to a size of a corresponding transport region. In this case, a value corresponding to the resource of the LBT failed subband is punctured and mapped to the transmission resource. The transmitting end may schedule and transmit the entire area, and may transmit a subband LBT execution result. The receiving end may receive the RB from a to b and decode the received value in the range of t-g to b + g as negligible.

On the other hand, an arbitrary start position may be introduced to start transmission from the middle even in a region where the LBT has failed. In this case, as shown in FIG. 14, in the LBT failure band, resources after a point where availability is secured and transmission can be started may not be punctured. The receiver may refer to the information transmitted to the corresponding area at the time of decoding based on the start position information implicitly or later transmitted.

According to another example, a transport block may be generated according to an area except for an LBT failure area in an uplink environment. In the uplink environment, the above description may be basically applied to the downlink environment. However, in the uplink environment, when the scheduling region itself cannot be adjusted and the LBT success or failure cannot be transmitted before decoding of a transport block such as a UCI in the PUSCH, the receiving base station initially detects whether the LBT fails or not. This is different from the case of downlink (blind detection), and the complexity increases as the number of subbands involved increases. Therefore, as described above in the first embodiment, it is possible to reduce the complexity of the base station by transmitting the LBT failure or not separately to DMRS or PUCCH.

According to another example, the LBT failure region may be punctured and transmitted in an uplink environment. Even in this case, the above description may be basically applied to the downlink environment. When the first decoding fails, the base station may receive the LBT failure information to increase decoding performance or request retransmission only of necessary portions. In this case, an additional operation for instructing retransmission may be defined to perform retransmission with the same value as the existing transmission value.

According to another example, whether to pre-generate or puncture a transport block may be indicated or transmitted. As described above, whether to perform transmission by pre-generating or puncturing may be determined in advance by the RRC according to the performance of the base station and the terminal, or may be delivered to the DCI according to the necessity at the time of transmission.

In the above description, the above description is basically based on NR-U transmission. However, the above description may be applied to all environments where channel availability is applied due to external factors. In addition, although the first embodiment and the second embodiment may be mutually applied, each sub-method may be independent of each other, and one or two or more may be applied separately as necessary.

Through the method provided by the present disclosure, broadband high-speed transmission may be performed in a channel environment in which some channels may not be used intermittently due to external factors such as NR-U. In addition, through the method provided by the present disclosure, the receiving end may obtain auxiliary information that may increase the reception success rate in the same channel environment, and the transport block may be tailored to the channel environment so as to efficiently support the reception and the decoding process based thereon. Can be reconfigured.

According to this, when resource allocation is performed over a plurality of subbands in an unlicensed band, wireless communication can be efficiently performed when some of the subbands of the corresponding resource are not available. In addition, by transmitting information on the LBT failure area, which is a subband in an unavailable state, wireless communication can be efficiently performed even when some of the subbands of the corresponding resource are not available.

Hereinafter, configurations of a terminal and a base station capable of performing some or all of the embodiments described with reference to FIGS. 1 to 16 will be described with reference to the drawings.

17 is a diagram illustrating a configuration of a user terminal 1700 according to another embodiment.

Referring to FIG. 17, a user terminal 1700 according to another embodiment includes a controller 1710, a transmitter 1720, and a receiver 1730.

The controller 1710 controls the overall operation of the user terminal 1700 according to the method for performing wireless communication in the unlicensed band required to perform the above-described present disclosure. The transmitter 1720 transmits uplink control information, data, and a message to a base station through a corresponding channel. The receiver 1730 receives downlink control information, data, and a message from a base station through a corresponding channel.

According to an example, the receiver 1730 may receive information for allocating radio resources in a system band including a plurality of subbands. The base station may allocate radio resources to be used for transmitting the downlink signal or channel to the terminal for the bandwidth part of the terminal. The terminal may receive the allocation information for the resource block (RB) in the frequency domain and the allocation information for the transmission start symbol and the duration in the time domain from the base station. According to an example, allocation information for a radio resource may be indicated through downlink control information (DCI).

In addition, the receiver 1730 may receive information on an LBT failure area of a radio resource. According to an example, the base station may transmit information on the LBT failure region to the terminal as a downlink signal or a channel. That is, information about an area where a downlink signal or a channel cannot be transmitted due to LBT failure among the allocated areas simultaneously with signal transmission may be explicitly indicated.

At least one subband of the plurality of subbands constituting the system band in the unlicensed band may be associated with the BWP of the terminal. In downlink, the base station may perform LBT on at least one subband associated with the BWP of the terminal before starting transmission for the corresponding terminal.

According to an example, the information on the LBT failure area may be indicated through downlink control information (DCI). The information on the LBT failure region may include information indicating whether the LBT succeeds for each of the at least one subbands associated with the BWP of the terminal, that is, each of the subbands included in the radio resource allocated to the terminal among the plurality of subbands. .

In this case, success or failure of LBT for each subband may be transmitted in a bitmap form by giving a field value to downlink control information. In addition, when multiple starting points are supported, starting points that can be transmitted for a subband in which LBT has failed may also be transmitted.

According to an example, the DCI including the information on the LBT failure area may be a DCI delivering the original data transmission area and method. In this case, the corresponding DCI may include LBT success information for the subband along with scheduling information for downlink transmission.

Or, the DCI including the information on the LBT failure area may be defined a new DCI format to deliver information about the LBT failure area. In this case, the corresponding DCI may not include scheduling information for downlink transmission, but may include information on whether LBT succeeds for the subband. In this case, the length of the message may be fixed to the number of subbands associated with the BWP allocated to each terminal, the number of subbands associated with the entire carrier band, or fixed to a specific value.

According to an example, subbands and bits may be mapped one-to-one in a bitmap. Alternatively, when the number of bits is larger than the number of subbands, the remaining bits may be padded to the length or set and then padded with the remaining bits, or repeated valid bits may be filled. Alternatively, when the number of bits is smaller than the number of subbands, two or more subbands may be mapped to one bit. In this case, the number of subbands corresponding to one bit may be all set the same, or may be set differently according to the number of bits and the number of subbands.

The DCI may be transmitted every time a downlink signal or channel is transmitted, or may be transmitted only when there is a failed subband. In addition, the DCI may be scrambled with an RNTI associated with a specific terminal and configured to receive only a specific terminal. Alternatively, the DCI may be configured to be scrambled with RNTIs associated with a plurality of terminals so that all terminals that can access the control resource set (CORESET) can receive them. That is, the receiver 1730 may receive a DCI including information on the LBT failure area through a UE group common physical downlink control channel (PDCCH).

The controller 1710 may monitor the downlink signal in an area excluding the LBT failure area from the radio resource and may receive the downlink signal through the receiver 1730.

The controller 1710 may monitor the downlink signal based on the allocation information on the radio resource and the information on the LBT failure area. That is, the controller 1710 may check the remaining subbands except for the subband in which the LBT has failed among the plurality of subbands constituting the radio resource allocated to the reception of the downlink signal. The receiver 1730 may receive a downlink signal from the base station through the remaining subbands.

According to an example, when multiple starting points are supported in the unlicensed band, the LBT may be performed again for the subband in which the LBT fails during the transmission of the downlink signal. When the LBT succeeds for the subband in which the LBT has failed, the receiver 1730 may receive information on the LBT success and transmission start point for the corresponding subband through the DCI. Accordingly, the controller 1710 may monitor a subband in which LBT is successful during downlink transmission after the transmission start point and receive a downlink signal.

According to this, when resource allocation is performed over a plurality of subbands in an unlicensed band, wireless communication can be efficiently performed when some of the subbands of the corresponding resource are not available. In addition, by transmitting information on the LBT failure area, which is a subband in an unavailable state, wireless communication can be efficiently performed even when some of the subbands of the corresponding resource are not available.

18 is a diagram illustrating a configuration of a base station 1800 according to another embodiment.

Referring to FIG. 18, a base station 1800 according to another embodiment includes a controller 1810, a transmitter 1820, and a receiver 1830.

The controller 1810 controls the overall operation of the base station 1800 according to the method for performing wireless communication in the unlicensed band required to perform the above-described present disclosure. The transmitter 1820 and the receiver 1830 are used to transmit and receive a signal, a message, and data necessary for carrying out the present disclosure.

According to an example, the controller 1810 may perform an LBT for each subband in a system band composed of a plurality of subbands in an unlicensed band. According to an example, assume an environment in which an unlicensed band consists of a plurality of subbands corresponding to 20 MHz, which is a LBT execution unit. For example, a band of 100 MHz consisting of five subbands can be assumed. At least one subband of the plurality of subbands may be configured as a BWP of the terminal.

The controller 1810 may perform an LBT process for checking whether a corresponding wireless channel is occupied by another node in order to transmit a wireless signal through an unlicensed band. That is, the controller 1810 may perform LBT on at least one subband configured with a BWP of the terminal in order to transmit a downlink signal or a channel to an arbitrary terminal in the unlicensed band. As a result of performing LBT, when the subband of the corresponding unlicensed band is not occupied, the controller 1810 may transmit a PDCCH and a corresponding PDSCH to the terminal through the transmitter 1820.

The transmitter 1820 may transmit information for allocating a radio resource in a system band, transmit information on an LBT failure area of the radio resource, and transmit a downlink signal in an area except the LBT failure area in the radio resource.

The controller 1810 may allocate a radio resource to be used for transmitting a downlink signal or a channel to the terminal for the bandwidth part of the terminal. The transmitter 1820 may transmit the allocation information on the resource block (RB) in the frequency domain and the transmission start symbol and the allocation information on the duration in the time domain to the terminal. According to an example, allocation information for a radio resource may be indicated through downlink control information (DCI).

According to an example, the transmitter 1820 may transmit information on the LBT failure area to the terminal when transmitting a downlink signal or a channel. That is, the transmitter 1820 may explicitly indicate information about a region in which the downlink signal or channel cannot be transmitted due to the LBT failure among the allocated regions simultaneously with the transmission of the signal.

According to an example, the information on the LBT failure area may be indicated through downlink control information (DCI). The information on the LBT failure region may include information indicating whether the LBT succeeds for each of the at least one subbands associated with the BWP of the terminal, that is, each of the subbands included in the radio resource allocated to the terminal among the plurality of subbands. .

In this case, success or failure of LBT for each subband may be transmitted in a bitmap form by giving a field value to downlink control information. In addition, when multiple starting points are supported, starting points that can be transmitted for a subband in which LBT has failed may also be transmitted.

According to an example, the DCI including the information on the LBT failure area may be a DCI delivering the original data transmission area and method. In this case, the corresponding DCI may include LBT success information for the subband along with scheduling information for downlink transmission.

Or, the DCI including the information on the LBT failure area may be defined a new DCI format to deliver information about the LBT failure area. In this case, the corresponding DCI may not include scheduling information for downlink transmission, but may include information on whether LBT succeeds for the subband. In this case, the length of the message may be fixed to the number of subbands associated with the BWP allocated to each terminal, the number of subbands associated with the entire carrier band, or fixed to a specific value.

According to an example, subbands and bits may be mapped one-to-one in a bitmap. Alternatively, when the number of bits is larger than the number of subbands, the remaining bits may be padded to the length or set and then padded with the remaining bits, or repeated valid bits may be filled. Alternatively, when the number of bits is smaller than the number of subbands, two or more subbands may be mapped to one bit. In this case, the number of subbands corresponding to one bit may be all set the same, or may be set differently according to the number of bits and the number of subbands.

The DCI may be transmitted every time a downlink signal or channel is transmitted, or may be transmitted only when there is a failed subband. In addition, the DCI may be scrambled with an RNTI associated with a specific terminal and configured to receive only a specific terminal.

Alternatively, the DCI may be configured to be scrambled with RNTIs associated with a plurality of terminals so that all terminals that can access the control resource set (CORESET) can receive them. To this end, a separate new RNTI for use in DCI including information on the LBT failure region for the subband may be defined. According to an example, the newly defined RNTI may be referred to as occupied subband indication RNTI (Occupied subband indication RNTI). However, this is not an example and is not limited to the corresponding name, and the newly defined RNTI may be referred to as another name.

The newly defined occupied subband indication RNTI may be pre-assigned for UE groups using an unlicensed band composed of a plurality of subbands. The CRC bit of the DCI including information on the LBT failure region for the subband may be scrambled to the occupied subband indication RNTI and transmitted through the PDCCH. Each terminal of the UE group may receive the DCI through the corresponding PDCCH, and check the CRC of the DCI by using the occupied subband indication RNTI. That is, the base station may transmit a DCI including information on the LBT failure area through a UE group common physical downlink control channel (PDCCH). Accordingly, all terminals that can access the corresponding CORESET can receive information about the LBT failure area, and in this case, the PDCCH used may be defined as a group common PDCCH (GC-PDCCH).

The transmitter 1820 may transmit a downlink signal to the terminal based on the allocation information on the radio resource and the information on the LBT failure area. That is, the controller 1810 may check the remaining subbands except for the subband in which the LBT fails among the plurality of subbands constituting the radio resource allocated to the reception of the downlink signal. The transmitter 1820 may transmit a downlink signal to the terminal through the remaining subbands.

According to an example, when multiple starting points are supported in the unlicensed band, the base station may perform LBT again on a subband in which LBT fails during transmission of a downlink signal. If the LBT succeeds for the subband in which the LBT has failed, the controller 1810 may transmit information on the LBT success and transmission start point for the corresponding subband to the terminal through the DCI. Accordingly, the terminal may receive a downlink signal by monitoring a subband in which LBT succeeds during downlink transmission after the corresponding transmission start point.

According to this, when resource allocation is performed over a plurality of subbands in an unlicensed band, wireless communication can be efficiently performed when some of the subbands of the corresponding resource are not available. In addition, by transmitting information on the LBT failure area, which is a subband in an unavailable state, wireless communication can be efficiently performed even when some of the subbands of the corresponding resource are not available.

The above-described embodiments may be supported by standard documents disclosed in at least one of the wireless access systems IEEE 802, 3GPP and 3GPP2. That is, steps, components, and parts which are not described in order to clearly reveal the present technical spirit of the embodiments may be supported by the aforementioned standard documents. In addition, all terms disclosed herein may be described by the standard documents disclosed above.

The above-described embodiments may be implemented through various means. For example, the embodiments may be implemented by hardware, firmware, software, or a combination thereof.

In the case of a hardware implementation, the method according to the embodiments may include one or more Application Specific Integrated Circuits (ASICs), Digital Signal Processors (DSPs), Digital Signal Processing Devices (DSPDs), Programmable Logic Devices (PLDs), FPGAs. (Field Programmable Gate Arrays), a processor, a controller, a microcontroller or a microprocessor may be implemented.

In the case of an implementation by firmware or software, the method according to the embodiments may be implemented in the form of an apparatus, procedure, or function for performing the functions or operations described above. The software code may be stored in a memory unit and driven by a processor. The memory unit may be located inside or outside the processor, and may exchange data with the processor by various known means.

In addition, the terms "system", "processor", "controller", "component", "module", "interface", "model", or "unit" described above generally refer to computer-related entity hardware, hardware and software. Can mean a combination of, software or running software. For example, the aforementioned components may be, but are not limited to, a process driven by a processor, a processor, a controller, a control processor, an object, an execution thread, a program, and / or a computer. For example, both an application running on a controller or processor and a controller or processor can be components. One or more components may be within a process and / or thread of execution, and the components may be located on one device (eg, system, computing device, etc.) or distributed across two or more devices.

The above description is merely illustrative of the technical idea of the present disclosure, and various modifications and variations may be made by those skilled in the art without departing from the essential characteristics of the present disclosure. In addition, the present embodiments are not intended to limit the technical spirit of the present disclosure but to describe the scope of the present inventive concept. The scope of protection of the present disclosure should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto shall be interpreted as being included in the scope of the present disclosure.

Claims (20)

In the method for the terminal to perform wireless communication in the unlicensed band,
Receiving information for allocating radio resources in a system band consisting of a plurality of subbands;
Receiving information on a failure before talk (LBT) region of the radio resource;
Monitoring a downlink signal in an area excluding the LBT failure area in the radio resource; And
Receiving the downlink signal. The method of claim 1,
The information on the LBT failure area is indicated through downlink control information (DCI). The method of claim 2,
The downlink control signal is scrambled with a Radio Network Temporary Identifier (RNTI) that is commonly applied to a plurality of UEs in the system band and is transmitted through a physical downlink control channel (PDCCH). The method of claim 1,
The information on the LBT failure region includes information indicating whether the LBT succeeds for each subband included in the radio resource among the plurality of subbands. The method of claim 4, wherein
The information indicating whether the LBT succeeds for each of the plurality of subbands is indicated in a bitmap manner. In the method for the base station to perform wireless communication in the unlicensed band,
Performing List Before Talk (LBT) for each subband in a system band consisting of a plurality of subbands;
Transmitting information allocating radio resources in the system band;
Transmitting information on an LBT failure area of the radio resource; And
Transmitting a downlink signal in an area excluding the LBT failure area in the radio resource. The method of claim 6,
The information on the LBT failure area is indicated through downlink control information (DCI). The method of claim 7, wherein
The downlink control signal is scrambled with a Radio Network Temporary Identifier (RNTI) that is commonly applied to a plurality of UEs in the system band and is transmitted through a physical downlink control channel (PDCCH). The method of claim 6,
The information on the LBT failure region includes information indicating whether the LBT succeeds for each subband included in the radio resource among the plurality of subbands. The method of claim 9,
The information indicating whether the LBT succeeds for each of the plurality of subbands is indicated in a bitmap manner. In the terminal performing wireless communication in the unlicensed band,
A receiver configured to receive information for allocating a radio resource in a system band including a plurality of subbands and to receive information about a failure before talk (LBT) region of the radio resources; And
And a control unit for receiving the downlink signal by monitoring a downlink signal in an area excluding the LBT failure area from the radio resource. The method of claim 11,
The information on the LBT failure area is indicated by a downlink control signal (DCI). The method of claim 12,
The downlink control signal is scrambled with a Radio Network Temporary Identifier (RNTI) commonly applied to a plurality of terminals in the system band and is transmitted through a physical downlink control channel (PDCCH). The method of claim 11,
The information on the LBT failure region includes information indicating whether the LBT succeeds for each subband included in the radio resource among the plurality of subbands. The method of claim 14,
Information indicating whether the LBT succeeds for each of the plurality of subbands is indicated by a bitmap method. A base station performing wireless communication in an unlicensed band,
A controller for performing List Before Talk (LBT) for each subband in a system band composed of a plurality of subbands; And
And a transmitter for transmitting information for allocating a radio resource in the system band, transmitting information on an LBT failure area among the radio resources, and transmitting a downlink signal in an area excluding the LBT failure area in the radio resource. Base station. The method of claim 16,
The base station, the information on the LBT failure area is indicated by a downlink control signal (downlink control information, DCI). The method of claim 17,
The downlink control signal is scrambled with a Radio Network Temporary Identifier (RNTI) that is commonly applied to a plurality of terminals of the system band and is transmitted through a physical downlink control channel (PDCCH). The method of claim 16,
The information on the LBT failure area, the base station including information indicating whether the success of the LBT for each of the subbands included in the radio resources of the plurality of subbands. The method of claim 19,
Information indicating whether the LBT success for each of the plurality of subbands is indicated in a bitmap (bitmap) method.

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