KR20210153492A - Method, apparatus, and system for receiving downlink channel and transmitting uplink channel in wireless communication system - Google Patents

Abstract

The present invention proposes a method for interpreting frequency domain resource allocation information in a DCI format for scheduling an uplink shared channel in an unlicensed band. A technical aspect of the present invention proposes a method for interpreting an RB set of a UL BWP indicated from an FDRA field of a DCI format, and a method for a DCI to interpret scheduling information of the received RB set and RB sets adjacent thereto.

Description

Method and apparatus for downlink reception and uplink transmission in a wireless communication system {METHOD, APPARATUS, AND SYSTEM FOR RECEIVING DOWNLINK CHANNEL AND TRANSMITTING UPLINK CHANNEL IN WIRELESS COMMUNICATION SYSTEM}

The present invention relates to a wireless communication system, and more particularly, to a method, apparatus, and system for downlink channel reception and uplink channel transmission in a wireless communication system.

3GPP LTE(-A) defines uplink/downlink physical channels for physical layer signal transmission. For example, a physical uplink shared channel (PUSCH), which is a physical channel for transmitting data in uplink, a physical uplink control channel (PUCCH) for transmitting a control signal, and a physical random access channel (PRACH) are defined, Physical downlink shared channel (PDSCH) for transmitting data in downlink, physical control format indicator channel (PCFICH) for transmitting L1/L2 control signals, physical downlink control channel (PDCCH), physical hybrid ARQ indicator channel (PHICH) ), etc.

Among the channels, the downlink control channel (PDCCH/EPDCCH) is a channel for the base station to transmit uplink/downlink scheduling allocation control information, uplink transmission power control information, and other control information to one or more terminals. Since there is a limit to the resources that can be used for the PDCCH that the base station can transmit at once, different resources cannot be allocated to each terminal, and control information must be transmitted to any terminal by sharing the resources. For example, in 3GPP LTE(-A), 4 REs (Resource Elements) are combined to create REG (Resource Element Group), 9 CCEs (Control Channel Elements) are created, and one or more CCEs can be combined and sent. The available resources are informed to the UE, and several UEs can share and use the CCE. Here, the number of CCEs combined is called a CCE binding level, and a resource to which CCEs are allocated according to a possible CCE binding level is called a search space. The search space may include a common search space defined for each base station and a terminal-specific or UE-specific search space defined for each terminal. The UE performs decoding on the number of all possible CCE combination cases in the search space, and can know whether it corresponds to its own PDCCH through the user equipment (UE) identifier included in the PDCCH. Therefore, the operation of the terminal takes a long time to decode the PDCCH and consumes a lot of energy.

After commercialization of the 4G (4th generation) communication system, efforts are being made to develop a new 5G (5th generation) communication system in order to meet the increasing demand for wireless data traffic. 5G communication system is called a 4G network after (beyond 4G network) communication system, LTE system after (post LTE) system or NR (new radio) system. In order to achieve a high data rate, the 5G communication system includes a system operated by using an ultra-high frequency (mmWave) band of 6 GHz or higher, and a communication system operated using a frequency band of 6 GHz or less in terms of securing coverage Implementation in the base station and the terminal, including

The 3rd generation partnership project (3GPP) NR system improves the spectral efficiency of the network, allowing carriers to provide more data and voice services in a given bandwidth. Therefore, the 3GPP NR system is designed to meet the demand for high-speed data and media transmission in addition to high-capacity voice support. The advantages of the NR system are that it can have low operating costs with high throughput, low latency, support for frequency division duplex (FDD) and time division duplex (TDD) on the same platform, improved end-user experience and simple architecture.

For more efficient data processing, dynamic TDD of the NR system may use a method of varying the number of orthogonal frequency division multiplexing (OFDM) symbols that can be used for uplink and downlink according to the data traffic direction of users of the cell. For example, when the downlink traffic of the cell is greater than the uplink traffic, the base station may allocate a plurality of downlink OFDM symbols to a slot (or subframe). Information on the slot configuration should be transmitted to the terminals.

In order to alleviate the path loss of radio waves and increase the propagation distance of radio waves in the ultra-high frequency band, in the 5G communication system, beamforming, massive MIMO, full dimensional MIMO, FD-MIMO ), an array antenna, analog beam-forming, a hybrid beamforming that combines analog beamforming and digital beamforming, and a large scale antenna technology are being discussed. In addition, for network improvement of the system, in the 5G communication system, an evolved small cell, an advanced small cell, a cloud radio access network (cloud radio access network: cloud RAN), an ultra-dense network (ultra-dense network) , device to device communication (D2D), vehicle to everything communication (V2X), wireless backhaul, non-terrestrial network communication (NTN), mobile network (moving network), cooperative communication (cooperative communication), CoMP (coordinated multi-points), and technology development related to reception interference cancellation (interference cancellation) and the like are being made. In addition, in the 5G system, hybrid FSK and QAM modulation (FQAM) and sliding window superposition coding (SWSC), which are advanced coding modulation (ACM) methods, and filter bank multi-carrier (FBMC), which is an advanced access technology, Non-orthogonal multiple access (NOMA) and sparse code multiple access (SCMA) are being developed.

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

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

In general, a mobile communication system has been developed to provide a voice service while ensuring user activity. However, the mobile communication system is gradually expanding its scope not only to voice but also to data services, and has now developed to the extent that it can provide high-speed data services. However, in a mobile communication system in which a service is currently provided, a more advanced mobile communication system is required because there is a shortage of resources and users demand a higher speed service.

In addition, in such a situation, a method of using an unlicensed frequency spectrum or a frequency band (eg, a 2.4 GHz band, a 5.8 GHz band, etc.) to provide a cellular communication service is being considered as a solution to the problem of a lack of spectrum.

However, in the case of an unlicensed band, since a number of communication facilities can be used simultaneously without restrictions if the telecommunication service provider does not secure an exclusive frequency use right through an auction, etc., but observes a certain level of adjacent band protection regulations, it is provided in the licensed band. It is difficult to guarantee a communication quality of a possible level, and an interference problem with a device performing wireless communication using an existing unlicensed band (eg, a Wi-Fi network) may occur.

Therefore, in order to establish LTE and NR-Unlicensed technologies in the unlicensed band, research on a method of coexistence with existing unlicensed band devices and a method of efficiently sharing a radio channel should be conducted in advance. That is, a robust coexistence mechanism (RCM) must be developed so that devices using LTE and NR-Unlicensed technologies in unlicensed bands do not affect existing unlicensed band devices.

Regarding standardization, in 3GPP, many telecommunication operators, including manufacturers including Qualcomm, are actively introducing standards for LTE and NR-Unlicensed technologies in unlicensed bands and continuously developing standard technologies, and Licensed assisted access including Standalone. And standardization is in progress so that it can be commercialized as a technology that can perform dual connectivity. In addition, under the condition that basic radio wave usage etiquette is observed in the frequency sharing band or the unlicensed low power band, various services and new technologies can be commercialized without designation of use. On the other hand, in Korea, most of the unlicensed bands, including the ISM band, are being operated for designated purposes, so technical research and related policy establishment for this should be preceded.

The present invention relates to a method, apparatus, and system for uplink channel transmission according to scheduling information through a downlink control channel in a 3GPP NR system.

The objects that can be achieved by the present invention are not limited to those specifically described herein.

In order to solve the above technical problem, in a technical aspect of the present invention, it is a method of interpreting the RB set of the UL BWP indicated from the FDRA field of the DCI format. suggest a way

In order to solve the above technical problem, as a technical aspect of the present invention, as a method of interpreting the interlace of the UL BWP indicated from the FDRA field of the DCI format, a method of tying the interlaces and interpreting them as scheduling information is proposed.

The above-described technical solutions are only a part of preferred embodiments of the present invention, and various modifications to which the technical features of the present invention are applied can be understood by those skilled in the art to which the present invention pertains, and referring to the following detailed description of the present invention, do.

According to an embodiment of the present invention, the terminal is expected to be able to perform uplink transmission according to the indication of the downlink control channel.

1 shows an example of a radio frame structure used in a wireless communication system.
2 shows an example of a downlink (DL)/uplink (UL) slot structure in a wireless communication system.
3 is a diagram for explaining a physical channel used in a 3GPP system and a general signal transmission method using the corresponding physical channel.
4 shows an SS/PBCH block for initial cell access in a 3GPP NR system.
5 shows a procedure for transmitting control information and a control channel in a 3GPP NR system.
6 is a diagram illustrating a control resource set (CORESET) through which a physical downlink control channel (PDCCH) can be transmitted in a 3GPP NR system.
7 is a diagram illustrating a method of configuring a PDCCH search space in a 3GPP NR system.
8 is a conceptual diagram illustrating carrier aggregation.
9 is a diagram for explaining single-carrier communication and multi-carrier communication.
10 is a diagram illustrating an example to which a cross-carrier scheduling technique is applied.
11 shows an NR-Unlicensed (NR-U) service environment.
12 shows an embodiment of a deployment scenario of a terminal and a base station in an NR-U service environment.
13 shows a communication method (eg, wireless LAN) that operates in an existing unlicensed band.
14 shows a channel access procedure based on Category 4 LBT according to an embodiment of the present invention.
15 shows an embodiment of a method for adjusting a contention window size (CWS) based on HARQ-ACK feedback.
16 is a block diagram showing the configurations of a terminal and a base station, respectively, according to an embodiment of the present invention.
17 is a diagram illustrating a method of indicating an RB set of a UL BWP using an RB set that has received a DCI format according to an embodiment of the present invention.
18 is a diagram illustrating a method of indicating a RB set of a UL BWP using an RB set that has received a DCI format according to an embodiment of the present invention.
19 is a diagram illustrating a method of instructing a RB set of a UL BWP by using the RB set of the UL BWP before BWP switching according to an embodiment of the present invention.
20 is a diagram illustrating a method of indicating an RB set when there is no RB set of a UL BWP overlapping an RB set having received a DCI format according to an embodiment of the present invention.
21 is a diagram illustrating a method of indicating an RB set when there is no RB set of a UL BWP overlapping an RB set that has received a DCI format according to an embodiment of the present invention.
22 is a diagram illustrating a method of indicating an RB set when there is no RB set of a UL BWP overlapping an RB set that has received a DCI format according to an embodiment of the present invention.
23 is a diagram illustrating a method of indicating a plurality of RB sets in a DCI format according to an embodiment of the present invention.
24 is a diagram illustrating a method of indicating a plurality of RB sets in a DCI format according to an embodiment of the present invention.
25 is a diagram illustrating a method of indicating a plurality of RB sets in a DCI format according to an embodiment of the present invention.

The terms used in the present specification have been selected as widely used general terms as possible while considering their functions in the present invention, but these may vary depending on intentions, conventions, or emergence of new technologies of those of ordinary skill in the art. In addition, in certain cases, there are terms arbitrarily selected by the applicant, and in this case, the meaning will be described in the description of the relevant invention. Therefore, it is intended to clarify that the terms used in this specification should be interpreted based on the actual meaning of the terms and the contents of the entire specification, rather than the names of simple terms.

Throughout the specification, when a component is said to be "connected" with another component, this includes not only the case where it is "directly connected" but also the case where it is "electrically connected" with another component interposed therebetween. do. In addition, when it is said that a certain component "includes" a specific component, this means that other components may be further included, rather than excluding other components, unless otherwise stated. In addition, the limitation of “greater than” or “less than” based on a specific threshold may be appropriately replaced with “greater than” or “less than”, respectively, according to embodiments.

The following technologies include code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), single carrier frequency division multiple access (SC-FDMA), etc. It can be used in various wireless access systems. CDMA may be implemented with a radio technology such as universal terrestrial radio access (UTRA) or CDMA2000. TDMA may be implemented with 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 with a radio technology such as IEEE 802.11 (ie, Wi-Fi), IEEE 802.16 (ie, WiMAX), IEEE 802-20, Evolved UTRA (E-UTRA), and the like. UTRA is part of the universal mobile telecommunications system (UMTS). 3GPP long term evolution (LTE) is a part of evolved UMTS (E-UMTS) using E-UTRA, and LTE-advanced (LTE-A) is an evolved version of 3GPP LTE. A system designed separately from 3GPP NR LTE/LTE-A to support eMBB (enhanced Mobile BroadBand), URLLC (Ultra-Reliable and Low Latency Communication), and mMTC (massive machine type communication) services, which are the requirements of IMT-2020. is a system for For clarity of explanation, 3GPP NR is mainly described, but the technical spirit of the present invention is not limited thereto.

Unless otherwise specified herein, the base station may include a next generation node B (gNB) defined in 3GPP NR. Also, unless otherwise specified, a terminal may include user equipment (UE).

1 shows an example of a radio frame structure used in a wireless communication system. Referring to FIG. 1 , a radio frame (or radio frame) used in a 3GPP NR system may have a length _{of 10 ms (Δf max} N _f / 100) * T _{c ).} In addition, the radio frame consists of 10 equally sized subframes (subframes, SFs). Here, Δ _max =480*10 ³ Hz, N _f =4096, T _c =1/(Δ _ref *N _f,ref ), Δ _ref =15*10 ³ Hz, N _f,ref =2048. 10 subframes in one radio frame may be assigned a number from 0 to 9, respectively. Each subframe has a length of 1 ms and may consist of one or a plurality of slots according to subcarrier spacing. More specifically, in the 3GPP NR system, the usable subcarrier spacing is 15*2 ^μ kHz. μ is a subcarrier spacing configuration factor, and may have a value of μ=0-4. That is, 15 kHz, 30 kHz, 60 kHz, 120 kHz, or 240 kHz may be used as the subcarrier spacing. A subframe of 1 ms length may consist ^{of 2 μ slots.} In this case, the length of each slot is 2 ^-μ ms. ^{2 μ} slots in one subframe may be numbered from 0 to 2 ^μ - 1, respectively. Also, slots in one radio frame may be assigned a number ^{from 0 to 10*2 μ - 1, respectively.} The time resource may be divided by at least one of a radio frame number (or also referred to as a radio frame index), a subframe number (or referred to as a subframe index), and a slot number (or a slot index).

2 shows an example of a downlink (DL)/uplink (UL) slot structure in a wireless communication system. In particular, FIG. 2 shows the structure of a resource grid of a 3GPP NR system. There is one resource grid per antenna port. Referring to FIG. 2 , a slot includes a plurality of orthogonal frequency division multiplexing (OFDM) symbols in the time domain and a plurality of resource blocks (RBs) in the frequency domain. The OFDM symbol also means one symbol interval. Unless otherwise specified, an OFDM symbol may be simply referred to as a symbol. 2, the signal transmitted in each slot is N ^{size, μ} _{grid, x} * N ^RB _sc number of subcarriers (subcarrier) and N ^slot _symb number of OFDM symbols composed of OFDM symbols (resource grid) can be expressed as have. Here, in the case of the downlink resource grid, x = DL, and in the case of the uplink resource grid, x = UL. N ^size,μ _grid,x represents the number of resource blocks (RBs) according to the subcarrier interval configuration factor μ (x is DL or UL), and N ^slot _symb represents the number of OFDM symbols in the slot. N ^RB _sc is the number of subcarriers constituting one RB, and N ^RB _sc =12. The OFDM symbol may be referred to as a cyclic prefix OFDM (CP-OFDM) symbol or a discrete Fourier transform spread OFDM (DFT-S-OFDM) symbol according to a multiple access scheme.

The number of OFDM symbols included in one slot may vary according to the length of a cyclic prefix (CP). For example, in the case of a normal CP, one slot may include 14 OFDM symbols, but in the case of an extended CP, one slot may include 12 OFDM symbols. In a specific embodiment, the extended CP may be used only at a 60 kHz subcarrier interval. 2 illustrates a case in which one slot consists of 14 OFDM symbols for convenience of description, embodiments of the present invention may be applied to slots having other numbers of OFDM symbols in the same manner. Referring to FIG. 2 , each OFDM symbol includes N ^{size, μ} _{grid, x} * N ^RB _sc subcarriers in the frequency domain. The type of subcarrier may be divided into a data subcarrier for data transmission, a reference signal subcarrier for transmission of a reference signal, and a guard band. The carrier frequency is also referred to as the center frequency (fc).

^{One RB may be defined as N RB} _sc (eg, 12) consecutive subcarriers in the frequency domain. For reference, a resource composed of one OFDM symbol and one subcarrier may be referred to as a resource element (RE) or a tone. Accordingly, one RB may be composed ^{of N slot} _symb * N ^RB _{sc resource elements.} Each resource element in the resource grid may be uniquely defined by an index pair (k, l) in one slot. ^{k is an index assigned from 0 to N size,μ} _grid,x * N ^RB _sc - 1 in the frequency domain, and l may be an index assigned from 0 to N ^slot _{symb - 1 in the time domain.}

In order for the terminal to receive a signal from the base station or to transmit a signal to the base station, the time/frequency synchronization of the terminal may need to be aligned with the time/frequency synchronization of the base station. This is because, only when the base station and the terminal are synchronized, the terminal can determine the time and frequency parameters required to perform demodulation of the DL signal and transmission of the UL signal at an accurate time.

Each symbol of a radio frame operating in time division duplex (TDD) or unpaired spectrum is at least one of a downlink symbol (DL symbol), an uplink symbol (UL symbol), or a flexible symbol (flexible symbol). It may consist of any one. In frequency division duplex (FDD) or paired spectrum, a radio frame operating as a downlink carrier may consist of a downlink symbol or a flexible symbol, and a radio frame operating as an uplink carrier may include an uplink symbol or It may be composed of flexible symbols. In the downlink symbol, downlink transmission is possible but uplink transmission is impossible, and in the uplink symbol, uplink transmission is possible but downlink transmission is impossible. Whether the flexible symbol is used for downlink or uplink may be determined according to a signal.

Information on the type of each symbol, that is, information indicating any one of a downlink symbol, an uplink symbol, and a flexible symbol may be composed of a cell-specific (cell-specific or common) RRC (radio resource control) signal. have. In addition, information on the type of each symbol may be additionally configured as a UE-specific (or dedicated, UE-specific) RRC signal. The base station uses the cell-specific RRC signal to i) the period of the cell-specific slot configuration, ii) the number of slots with only downlink symbols from the beginning of the period of the cell-specific slot configuration, iii) the slot immediately following the slot with only downlink symbols. The number of downlink symbols from the first symbol, iv) the number of slots with only uplink symbols from the end of the cell-specific slot configuration period, v) the number of uplink symbols from the last symbol of the slot immediately preceding the slot with only uplink symbols let me know Here, a symbol that is not composed of either an uplink symbol or a downlink symbol is a flexible symbol.

When the information on the symbol type is configured as a UE-specific RRC signal, the base station may signal whether the flexible symbol is a downlink symbol or an uplink symbol with a cell-specific RRC signal. In this case, the UE-specific RRC signal cannot change the downlink symbol or the uplink symbol composed of the cell-specific RRC signal to another symbol type. The UE-specific RRC signal may signal the number of downlink symbols among ^{N slot} _symb symbols of the corresponding slot and the number of uplink symbols among ^{N slot} _{symb symbols of the corresponding slot for each slot.} In this case, the downlink symbol of the slot may be continuously configured from the first symbol of the slot to the i-th symbol. In addition, the uplink symbol of the slot may be continuously configured from the j-th symbol to the last symbol of the slot (here, i<j). A symbol that is not composed of either an uplink symbol or a downlink symbol in a slot is a flexible symbol.

A symbol type composed of the above RRC signal may be referred to as a semi-static DL/UL configuration. In the semi-static DL/UL configuration configured with the RRC signal above, the flexible symbol is a downlink symbol, an uplink symbol through dynamic slot format information (SFI) transmitted through a physical downlink control channel (PDCCH). , or may be indicated by a flexible symbol. In this case, the downlink symbol or the uplink symbol composed of the RRC signal is not changed to another symbol type. Table 1 illustrates the dynamic SFI that the base station can indicate to the terminal.

In Table 1, D denotes a downlink symbol, U denotes an uplink symbol, and X denotes a flexible symbol. As shown in Table 1, DL/UL switching may be allowed up to two times within one slot.

3 is a diagram for explaining a physical channel used in a 3GPP system (eg, NR) and a general signal transmission method using the corresponding physical channel. When the power of the terminal increases or the terminal enters a new cell, the terminal performs an initial cell search operation (S101). Specifically, the terminal may synchronize with the base station in the initial cell search. To this end, the terminal may receive a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) from the base station, synchronize with the base station, and obtain information such as a cell ID. Thereafter, the terminal may receive the physical broadcast channel from the base station to obtain broadcast information in the cell.

After completing the initial cell search, the UE receives a physical downlink control channel (PDCCH) and a physical downlink shared channel (PDSCH) according to information carried on the PDCCH, thereby acquiring through initial cell search. It is possible to obtain more specific system information than one system information (S102).

When the terminal accesses the base station for the first time or there is no radio resource for signal transmission, the terminal may perform a random access procedure with respect to the base station (steps S103 to S106). First, the UE may transmit a preamble through a physical random access channel (PRACH) (S103), and receive a response message to the preamble from the base station through a PDCCH and a corresponding PDSCH (S104). When a valid random access response message is received from the terminal, the terminal transmits data including its identifier through a physical uplink shared channel (PUSCH) indicated by the uplink grant delivered through the PDCCH from the base station. It is transmitted to the base station (S105). Next, the terminal waits for the reception of the PDCCH as an indication of the base station for collision resolution. When the terminal successfully receives the PDCCH through its identifier (S106), the random access process ends.

After the procedure described above, the UE receives PDCCH/PDSCH (S107) and a physical uplink shared channel (PUSCH)/physical uplink control channel (PUCCH) as a general uplink/downlink signal transmission procedure. may be transmitted (S108). In particular, the UE may receive downlink control information (DCI) through the PDCCH. DCI may include control information such as resource allocation information for the terminal. Also, the format of the DCI may vary depending on the purpose of use. The uplink control information (UCI) transmitted by the terminal to the base station through the uplink is a downlink/uplink ACK/NACK signal, a channel quality indicator (CQI), a precoding matrix index (PMI), and a rank indicator (RI). ) and the like. Here, CQI, PMI, and RI may be included in CSI (channel state information). In the case of the 3GPP NR system, the UE may transmit control information such as HARQ-ACK and CSI described above through PUSCH and/or PUCCH.

4 shows an SS/PBCH block for initial cell access in a 3GPP NR system. When the terminal is powered on or wants to access a cell anew, it may acquire time and frequency synchronization with the cell and perform an initial cell search process. The UE may detect the ^{physical cell identity N cell} _ID of the cell in the cell search process. To this end, the terminal may receive a synchronization signal, for example, a main synchronization signal (PSS) and a secondary synchronization signal (SSS) from the base station to synchronize with the base station. In this case, the terminal may obtain information such as a cell identifier (identity, ID).

A synchronization signal (SS) will be described in more detail with reference to FIG. 4( a ). The synchronization signal may be divided into PSS and SSS. PSS may be used to obtain time domain synchronization and/or frequency domain synchronization such as OFDM symbol synchronization, slot synchronization. SSS may be used to obtain frame synchronization and cell group ID. Referring to FIG. 4(a) and Table 2, the SS/PBCH block may be composed of 20 RBs (=240 subcarriers) contiguous in the frequency axis, and may be composed of 4 OFDM symbols contiguous in the time axis. In this case, in the SS/PBCH block, the PSS is transmitted in the first OFDM symbol, and the SSS is transmitted through the 56th to 182th subcarriers in the third OFDM symbol. Here, the lowest subcarrier index of the SS/PBCH block is numbered from 0. In the first OFDM symbol in which the PSS is transmitted, the base station does not transmit a signal through the remaining subcarriers, that is, the 0 to 55 and 183 to 239 subcarriers. In addition, the base station does not transmit a signal through the 48th to 55th and 183th to 191th subcarriers in the third OFDM symbol in which the SSS is transmitted. The base station transmits a physical broadcast channel (PBCH) through the remaining REs except for the above signal in the SS/PBCH block.

SS specifies a total of 1008 unique physical layer cell IDs through a combination of three PSSs and SSSs, and each physical layer cell ID is a part of only one physical-layer cell-identifier group. Preferably, each group can be grouped into 336 physical-layer cell-identifier groups containing three unique identifiers. Therefore, physical layer cell ID N ^cell _ID = 3N ⁽¹⁾ _ID + N ⁽²⁾ _ID ^{is an index N (1)} _ID in the range from 0 to 335 indicating a physical-layer cell-identifier group and the physical-layer cell - Can be uniquely defined by ^{the index N (2)} _ID from 0 to 2 indicating the physical-layer identifier in the identifier group. The UE may identify one of three unique physical-layer identifiers by detecting the PSS. In addition, the UE may identify one of 336 physical layer cell IDs associated with the physical-layer identifier by detecting the SSS. In this case, the sequence d _PSS (n) of the PSS is as follows.

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In addition, the sequence d _SSS (n) of the SSS is as follows.

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is given as

A radio frame with a length of 10 ms can be divided into two half frames with a length of 5 ms. A slot in which an SS/PBCH block is transmitted in each half frame will be described with reference to FIG. 4(b). The slot in which the SS/PBCH block is transmitted may be any one of cases A, B, C, D, and E. In case A, the subcarrier interval is 15 kHz, and the start time of the SS/PBCH block is {2, 8} + 14*nth symbol. In this case, n=0, 1 may be at a carrier frequency of 3 GHz or less. In addition, n=0, 1, 2, 3 may be in a carrier frequency of more than 3 GHz and less than or equal to 6 GHz. In case B, the subcarrier interval is 30 kHz, and the start time of the SS/PBCH block is {4, 8, 16, 20} + 28*nth symbol. In this case, n=0 at a carrier frequency of 3 GHz or less. In addition, n=0, 1 may be in the carrier frequency of more than 3 GHz and less than or equal to 6 GHz. In Case C, the subcarrier interval is 30 kHz, and the start time of the SS/PBCH block is {2, 8} + 14*nth symbol. In this case, n=0, 1 may be at a carrier frequency of 3 GHz or less. In addition, n=0, 1, 2, 3 may be in a carrier frequency of more than 3 GHz and less than or equal to 6 GHz. In case D, the subcarrier interval is 120 kHz, and the start time of the SS/PBCH block is {4, 8, 16, 20} + 28*nth symbol. In this case, n=0, 1, 2, 3, 5, 6, 7, 8, 10, 11, 12, 13, 15, 16, 17, 18 at a carrier frequency of 6 GHz or higher. In case E, the subcarrier interval is 240 kHz, and the start time of the SS/PBCH block is {8, 12, 16, 20, 32, 36, 40, 44} + 56*nth symbol. In this case, n=0, 1, 2, 3, 5, 6, 7, 8 may be at a carrier frequency of 6 GHz or higher.

5 shows a procedure for transmitting control information and a control channel in a 3GPP NR system. Referring to FIG. 5A , the base station may add a cyclic redundancy check (CRC) masked (eg, XOR operation) with a radio network temporary identifier (RNTI) to control information (eg, downlink control information, DCI). (S202). The base station may scramble the CRC with an RNTI value determined according to the purpose/target of each control information. The common RNTI used by one or more terminals is at least one of a system information RNTI (SI-RNTI), a paging RNTI (P-RNTI), a random access RNTI (RA-RNTI), and a transmit power control RNTI (TPC-RNTI). may include In addition, the UE-specific RNTI may include at least one of a cell temporary RNTI (C-RNTI) and a CS-RNTI. Thereafter, after performing channel encoding (eg, polar coding) (S204), the base station may perform rate-matching according to the amount of resource(s) used for PDCCH transmission (S206). Thereafter, the base station may multiplex DCI(s) based on a control channel element (CCE)-based PDCCH structure (S208). In addition, the base station may apply an additional process (S210) such as scrambling, modulation (eg, QPSK), interleaving, etc. to the multiplexed DCI(s), and then map the multiplexed DCI(s) to a resource to be transmitted. A CCE is a basic resource unit for a PDCCH, and one CCE may consist of a plurality (eg, six) of a resource element group (REG). One REG may consist of a plurality (eg, 12) of REs. The number of CCEs used for one PDCCH may be defined as an aggregation level. In the 3GPP NR system, aggregation levels of 1, 2, 4, 8 or 16 may be used. FIG. 5(b) is a diagram related to multiplexing of a CCE aggregation level and a PDCCH, and shows the types of CCE aggregation levels used for one PDCCH and CCE(s) transmitted in the control region accordingly.

6 is a diagram illustrating a control resource set (CORESET) through which a physical downlink control channel (PDCCH) can be transmitted in a 3GPP NR system. CORESET is a time-frequency resource through which PDCCH, which is a control signal for a terminal, is transmitted. In addition, a search space to be described later may be mapped to one CORESET. Therefore, the UE can decode the PDCCH mapped to the CORESET by monitoring the time-frequency domain designated as CORESET, rather than monitoring all frequency bands for PDCCH reception. The base station may configure one or a plurality of CORESETs for each cell to the terminal. CORESET may consist of up to three consecutive symbols on the time axis. In addition, CORESET may be configured in units of 6 consecutive PRBs on the frequency axis. 5, CORESET#1 consists of continuous PRBs, and CORESET#2 and CORESET#3 consist of discontinuous PRBs. CORESET may be located in any symbol within a slot. For example, in the embodiment of Figure 5, CORESET#1 starts at the 1st symbol of the slot, CORESET#2 starts at the 5th symbol of the slot, and CORESET#9 starts at the 9th symbol of the slot.

7 is a diagram illustrating a method of configuring a PDCCH search space in a 3GPP NR system. In order to transmit the PDCCH to the UE, at least one search space may exist in each CORESET. In the embodiment of the present invention, the search space is a set of all time-frequency resources (hereinafter, PDCCH candidates) through which the PDCCH of the UE can be transmitted. The search space may include a common search space that a terminal of 3GPP NR searches for and a terminal-specific or UE-specific search space that a specific terminal searches for. In the common search space, it is possible to monitor the PDCCH configured to be commonly found by all terminals in the cell belonging to the same base station. In addition, the UE-specific search space may be configured for each UE so that the PDCCH allocated to each UE can be monitored in different search space positions depending on the UE. In the case of the UE-specific search space, due to a limited control region to which the PDCCH can be allocated, search spaces between terminals may be allocated partially overlapping each other. Monitoring the PDCCH includes blind decoding of PDCCH candidates in the search space. A case in which blind decoding is successful is expressed as that the PDCCH is detected/received (successfully), and a case in which blind decoding is unsuccessful may be expressed as non-detection/non-receipt of the PDCCH, or it may be expressed as not successfully detected/received.

For convenience of explanation, a PDCCH scrambled with a group common (GC) RNTI that UEs already know in order to transmit downlink control information to one or more UEs is referred to as a group common (GC) PDCCH or a common PDCCH. refers to In addition, in order to transmit uplink scheduling information or downlink scheduling information to one specific UE, a PDCCH scrambled with a UE-specific RNTI that a specific UE already knows is referred to as a UE-specific PDCCH. The common PDCCH may be included in the common search space, and the UE-specific PDCCH may be included in the common search space or the UE-specific PDCCH.

The base station transmits information related to resource allocation of a paging channel (PCH) and a downlink-shared channel (DL-SCH) that are transport channels through the PDCCH (ie, DL Grant) or resource allocation of UL-SCH and hybrid automatic repeat request (HARQ). Information related to (ie, UL grant) may be informed to each UE or UE group. The base station may transmit the PCH transport block and the DL-SCH transport block through the PDSCH. The base station may transmit data excluding specific control information or specific service data through the PDSCH. In addition, the UE may receive data excluding specific control information or specific service data through the PDSCH.

The base station may transmit information on which terminal (one or a plurality of terminals) the PDSCH data is transmitted to and how the corresponding terminal should receive and decode the PDSCH data by including it in the PDCCH. For example, the DCI transmitted to a specific PDCCH is CRC-masked with an RNTI of “A”, and the DCI indicates that the PDSCH is allocated to a radio resource (eg, frequency location) of “B”, and “C” It is assumed that transmission format information (eg, transport block size, modulation scheme, coding information, etc.) is indicated. The UE monitors the PDCCH using its own RNTI information. In this case, if there is a terminal that blindly decodes the PDCCH with the "A" RNTI, the corresponding terminal receives the PDCCH, and receives the PDSCH indicated by "B" and "C" through the received PDCCH information.

Table 3 shows an embodiment of a physical uplink control channel (PUCCH) used in a wireless communication system.

The PUCCH may be used to transmit the following uplink control information (UCI).

- SR (scheduling request): information used to request uplink UL-SCH resources.

- HARQ-ACK: A response to a PDCCH (indicating DL SPS release) and/or a response to a downlink transport block (TB) on the PDSCH. HARQ-ACK indicates whether information transmitted through PDCCH or PDSCH is received. The HARQ-ACK response includes positive ACK (simply, ACK), negative ACK (hereinafter, NACK), discontinuous transmission (DTX) or NACK/DTX. Here, the term HARQ-ACK is used interchangeably with HARQ-ACK/NACK and ACK/NACK. In general, ACK may be expressed as a bit value of 1, and NACK may be expressed as a bit value of 0.

- CSI (channel state information): feedback information for a downlink channel. The terminal is generated based on a CSI-RS (reference signal) transmitted by the base station. Multiple input multiple output (MIMO)-related feedback information includes a rank indicator (RI) and a precoding matrix indicator (PMI). CSI may be divided into CSI part 1 and CSI part 2 according to information indicated by the CSI.

In the 3GPP NR system, five PUCCH formats may be used to support various service scenarios, various channel environments, and frame structures.

PUCCH format 0 is a format capable of transmitting 1-bit or 2-bit HARQ-ACK information or SR. PUCCH format 0 may be transmitted through one or two OFDM symbols on the time axis and one RB on the frequency axis. When PUCCH format 0 is transmitted in two OFDM symbols, the same sequence in two symbols may be transmitted in different RBs. Through this, the terminal can obtain a frequency diversity gain. More specifically, the terminal M _bit bit _{UCI (M bit = 1 or 2} ) in accordance with a cyclic shift of the base sequence determining a value m _cs of the (cyclic shift), and the length 12 (base sequence) of a predetermined value m _cs Im The click-shifted sequence may be mapped to 12 REs of one OFDM symbol and one PRB and transmitted. When the number of cyclic shifts usable by the UE is 12 and M _bit = 1, 1-bit UCI 0 and 1 can be expressed as a sequence corresponding to two cyclic shifts in which the difference between the cyclic shift values is 6. In addition, when M _bit = 2, 2-bit UCI 00, 01, 11, and 10 may be expressed as a sequence corresponding to four cyclic shifts having a difference of three cyclic shift values.

PUCCH format 1 may carry 1-bit or 2-bit HARQ-ACK information or SR. PUCCH format 1 may be transmitted through consecutive OFDM symbols on the time axis and one PRB on the frequency axis. Here, the number of OFDM symbols occupied by PUCCH format 1 may be one of 4 to 14. More specifically _{, UCI with M bit} = 1 may be modulated with BPSK. The UE may _{modulate UCI with M bit} = 2 by quadrature phase shift keying (QPSK). A signal is obtained by multiplying a modulated complex valued symbol d(0) by a sequence of length 12. The UE spreads the obtained signal in an even-numbered OFDM symbol to which PUCCH format 1 is allocated as a time axis orthogonal cover code (OCC) and transmits it. In PUCCH format 1, the maximum number of different terminals multiplexed to the same RB is determined according to the length of the OCC used. A demodulation reference signal (DMRS) may be spread and mapped to odd-numbered OFDM symbols of PUCCH format 1 as OCC.

PUCCH format 2 may carry more than 2 bits of UCI. PUCCH format 2 may be transmitted through one or two OFDM symbols on a time axis and one or a plurality of RBs on a frequency axis. When PUCCH format 2 is transmitted with two OFDM symbols, the same sequence may be transmitted on different RBs through the two OFDM symbols. Through this, the terminal can obtain a frequency diversity gain. More specifically, M _bit bit UCI (M _bit >2) is bit-level scrambled, QPSK modulated and mapped to RB(s) of one or two OFDM symbol(s). Here, the number of RBs may be one of 1 to 16.

PUCCH format 3 or PUCCH format 4 may carry more than 2 bits of UCI. PUCCH format 3 or PUCCH format 4 may be transmitted through consecutive OFDM symbols on the time axis and one PRB on the frequency axis. The number of OFDM symbols occupied by PUCCH format 3 or PUCCH format 4 may be one of 4 to 14. Specifically, the terminal may generate a complex number symbol d (0) ~ d (M symb -1) and modulated to M-bit _bit UCI (M _bit> 2) the πPhase Shift Keying) or QPSK. Here, when π is used, M _symb = M _bit , and when QPSK is used, M _symb = M _bit /2. The UE may not apply block-unit spreading to PUCCH format 3. However, the UE uses a PreDFT-OCC of length-12 length so that the PUCCH format 4 can have 2 or 4 multiplexing capacity in 1 RB (ie, 12 subcarriers) block-unit spreading can be applied. The UE may transmit precoding (or DFT-precoding) the spread signal and map it to each RE to transmit the spread signal.

In this case, the number of RBs occupied by PUCCH format 2, PUCCH format 3, or PUCCH format 4 may be determined according to the length of UCI transmitted by the UE and the maximum code rate. When the UE uses PUCCH format 2, the UE may transmit HARQ-ACK information and CSI information together through PUCCH. If the number of RBs that the UE can transmit is greater than the maximum number of RBs available for PUCCH format 2, PUCCH format 3, or PUCCH format 4, the UE does not transmit some UCI information according to the priority of UCI information and does not transmit the remaining Only UCI information can be transmitted.

PUCCH format 1, PUCCH format 3, or PUCCH format 4 may be configured through an RRC signal to indicate frequency hopping in a slot. When frequency hopping is configured, an index of an RB to be frequency hopping may be configured as an RRC signal. When PUCCH format 1, PUCCH format 3, or PUCCH format 4 is transmitted over N OFDM symbols in the time axis, the first hop has floor (N/2) OFDM symbols and the second hop is ceil ( It may have N/2) OFDM symbols.

PUCCH format 1, PUCCH format 3, or PUCCH format 4 may be configured to be repeatedly transmitted in a plurality of slots. In this case, the number K of slots in which the PUCCH is repeatedly transmitted may be configured by the RRC signal. The repeatedly transmitted PUCCH should start from an OFDM symbol at the same position in each slot and have the same length. If any one OFDM symbol among the OFDM symbols of the slot in which the UE should transmit the PUCCH is indicated as a DL symbol by the RRC signal, the UE may transmit the PUCCH by delaying it to the next slot without transmitting the PUCCH in the corresponding slot.

Meanwhile, in the 3GPP NR system, the UE may perform transmission/reception using a bandwidth equal to or smaller than the bandwidth of a carrier (or cell). To this end, the terminal may be configured with a bandwidth part (BWP) composed of a continuous bandwidth of a part of the bandwidth of the carrier. A UE operating according to TDD or operating in an unpaired spectrum may be configured with up to four DL/UL BWP pairs in one carrier (or cell). Also, the UE may activate one DL/UL BWP pair. A terminal operating according to FDD or operating in a paired spectrum may be configured with up to 4 DL BWPs on a downlink carrier (or cell) and up to 4 UL BWPs on an uplink carrier (or cell) can be configured. The UE may activate one DL BWP and one UL BWP for each carrier (or cell). The UE may not receive or transmit in time-frequency resources other than the activated BWP. The activated BWP may be referred to as an active BWP.

The base station may indicate the activated BWP among the BWPs configured by the terminal with downlink control information (DCI). BWP indicated by DCI is activated, and other configured BWP(s) are deactivated. In a carrier (or cell) operating in TDD, the base station may include a bandwidth part indicator (BPI) indicating the activated BWP in DCI scheduling PDSCH or PUSCH to change the DL/UL BWP pair of the terminal. The UE may receive a DCI scheduling a PDSCH or a PUSCH and identify an activated DL/UL BWP pair based on the BPI. In the case of a downlink carrier (or cell) operating in FDD, the base station may include the BPI indicating the activated BWP in the DCI scheduling the PDSCH to change the DL BWP of the terminal. In the case of an uplink carrier (or cell) operating in FDD, the base station may include the BPI indicating the activated BWP in the DCI scheduling the PUSCH to change the UL BWP of the terminal.

8 is a conceptual diagram illustrating carrier aggregation. In the carrier aggregation, in order for the wireless communication system to use a wider frequency band, a frequency block or (logical meaning) of a terminal consisting of an uplink resource (or component carrier) and/or a downlink resource (or component carrier) or a plurality of cells It means how to use it as one large logical frequency band. Hereinafter, for convenience of description, the term "component carrier" will be used.

Referring to FIG. 8 , as an example of a 3GPP NR system, the entire system band may include up to 16 component carriers, and each component carrier may have a bandwidth of up to 400 MHz. A component carrier may include one or more physically contiguous subcarriers. 8 shows that each component carrier has the same bandwidth, but this is only an example, and each component carrier may have a different bandwidth. In addition, although each component carrier is illustrated as being adjacent to each other on the frequency axis, the figure is illustrated in a logical concept, and each component carrier may be physically adjacent to each other or may be separated from each other.

A different center frequency may be used in each component carrier. In addition, one center frequency common to physically adjacent component carriers may be used. Assuming that all component carriers are physically adjacent to each other in the embodiment of FIG. 8 , the center frequency A may be used in all component carriers. In addition, assuming that the respective component carriers are not physically adjacent to each other, the center frequency A and the center frequency B may be used in each of the component carriers.

When the entire system band is extended by carrier aggregation, a frequency band used for communication with each terminal may be defined in units of component carriers. Terminal A can use 100 MHz, which is the entire system band, and performs communication using all five component carriers. Terminals B ₁ to B ₅ can use only a 20 MHz bandwidth and perform communication using one component carrier. Terminals C ₁ and C ₂ may use a 40 MHz bandwidth and perform communication using two component carriers, respectively. Two component carriers may or may not be logically/physically adjacent. The embodiment of FIG. 8 shows a case in which terminal C ₁ uses two non-adjacent component carriers and terminal C ₂ uses two adjacent component carriers.

9 is a diagram for explaining single carrier communication and multi-carrier communication. In particular, FIG. 9(a) shows a subframe structure of a single carrier, and FIG. 9(b) shows a subframe structure of a multi-carrier.

Referring to FIG. 9A , in the case of the FDD mode, a general wireless communication system may transmit or receive data through one DL band and one UL band corresponding thereto. In another specific embodiment, in the case of the TDD mode, the wireless communication system divides a radio frame into an uplink time unit and a downlink time unit in the time domain, and may transmit or receive data through the uplink/downlink time unit. . Referring to FIG. 9B , a bandwidth of 60 MHz may be supported by collecting three 20 MHz component carriers (CCs) in the UL and the DL, respectively. Each of the CCs may be adjacent to or non-adjacent to each other in the frequency domain. 9(b) shows a case in which both the bandwidth of the UL CC and the bandwidth of the DL CC are identical and symmetric for convenience, but the bandwidth of each CC may be independently determined. In addition, asymmetric carrier aggregation in which the number of UL CCs and the number of DL CCs are different is possible. A DL/UL CC allocated/configured to a specific UE through RRC may be referred to as a serving DL/UL CC of a specific UE.

The base station may communicate with the terminal by activating some or all of the serving CCs of the terminal or by deactivating some CCs. The base station may change activated/deactivated CCs, and may change the number of activated/deactivated CCs. If the base station allocates the available CCs to the terminal in a cell-specific or terminal-specific manner, unless the CC allocation to the terminal is completely reconfigured or the terminal is handover, at least one of the CCs once allocated is not deactivated. it may not be One CC that is not deactivated to the UE is called a primary CC (PCC) or PCell (primary cell), and a CC that the base station can freely activate/deactivate is a secondary CC (SCC) or a secondary cell (SCell). ) is called

Meanwhile, 3GPP NR uses the concept of a cell to manage radio resources. A cell is defined as a combination of downlink and uplink resources, that is, a combination of DL CC and UL CC. A cell may be configured with a DL resource alone or a combination of a DL resource and a UL resource. When carrier aggregation is supported, linkage between the carrier frequency of the DL resource (or DL CC) and the carrier frequency of the UL resource (or UL CC) may be indicated by system information. The carrier frequency means the center frequency of each cell or CC. A cell corresponding to the PCC is referred to as a PCell, and a cell corresponding to the SCC is referred to as an SCell. A carrier corresponding to the PCell in the downlink is a DL PCC, and a carrier corresponding to the PCell in the uplink is a UL PCC. Similarly, a carrier corresponding to the SCell in the downlink is a DL SCC, and a carrier corresponding to the SCell in the uplink is a UL SCC. According to the terminal capability (capability), the serving cell(s) may be composed of one PCell and zero or more SCells. For a UE that is in the RRC_CONNECTED state but does not have carrier aggregation configured or does not support carrier aggregation, there is only one serving cell configured only with PCell.

As mentioned above, the term "cell" used in carrier aggregation is distinguished from the term "cell" that refers to a certain geographic area in which a communication service is provided by one base station or one antenna group. In order to distinguish a cell indicating a certain geographic area from a cell of carrier aggregation, in the present invention, a cell of carrier aggregation is referred to as a CC, and a cell of the geographic area is referred to as a cell.

10 is a diagram illustrating an example to which a cross-carrier scheduling technique is applied. When cross-carrier scheduling is configured, the control channel transmitted through the first CC may schedule the data channel transmitted through the first CC or the second CC using a carrier indicator field (CIF). CIF is contained within DCI. In other words, a scheduling cell is configured, and the DL grant/UL grant transmitted in the PDCCH region of the scheduling cell schedules the PDSCH/PUSCH of the scheduled cell. That is, a search region for a plurality of component carriers exists in the PDCCH region of the scheduling cell. A PCell is basically a scheduling cell, and a specific SCell may be designated as a scheduling cell by a higher layer.

In the embodiment of FIG. 10 , it is assumed that three DL CCs are merged. Here, it is assumed that DL component carrier #0 is a DL PCC (or PCell), and DL component carrier #1 and DL component carrier #2 are assumed to be DL SCC (or SCell). Also, it is assumed that the DL PCC is set as the PDCCH monitoring CC. If cross-carrier scheduling is not configured by UE-specific (or UE-group-specific or cell-specific) higher layer signaling, CIF is disabled, and each DL CC has its own without CIF according to the NR PDCCH rule. It is possible to transmit only the PDCCH scheduling the PDSCH of (non-cross-carrier scheduling, self-carrier scheduling). On the other hand, when cross-carrier scheduling is configured by UE-specific (or UE-group-specific or cell-specific) higher layer signaling, CIF is enabled, and a specific CC (eg, DL PCC) uses CIF. Thus, not only the PDCCH scheduling the PDSCH of DL CC A but also the PDCCH scheduling the PDSCH of another CC can be transmitted (cross-carrier scheduling). On the other hand, the PDCCH is not transmitted in other DL CCs. Therefore, the UE receives a self-carrier scheduled PDSCH by monitoring a PDCCH not including a CIF depending on whether cross-carrier scheduling is configured for the UE, or monitors a PDCCH including a CIF to monitor a cross-carrier scheduled PDSCH receive

Meanwhile, although FIGS. 9 and 10 exemplify the subframe structure of the 3GPP LTE-A system, the same or similar configuration may be applied to the 3GPP NR system. However, in the 3GPP NR system, the subframes of FIGS. 9 and 10 may be replaced with slots.

<Communication method in unlicensed band>

11 illustrates an NR-Unlicensed (NR-U) service environment.

Referring to FIG. 11 , a service environment in which NR-U, which is an NR technology 11 in a licensed band and an NR technology 12 in an unlicensed band, is grafted may be provided to a user. For example, in the NR-U environment, the NR technology 11 in the licensed band and the NR technology 12 in the unlicensed band may be integrated using a technology such as carrier aggregation, which may contribute to network capacity expansion. . In addition, in an asymmetric traffic structure with more downlink data than uplink data, NR-U can provide an NR service optimized for various needs or environments. For convenience, the NR technology in the licensed band is referred to as NR-L (NR-Licensed), and the NR technology in the unlicensed band is referred to as NR-U (NR-Unlicensed).

12 shows an embodiment of a deployment scenario of a terminal and a base station in an NR-U service environment. The frequency band targeted by the NR-U service environment does not have a long wireless communication reach due to its high-frequency characteristics. Considering this, the deployment scenario of the terminal and the base station in an environment where the existing NR-L service and the NR-U service coexist may be an overlay model or a co-located model.

In the overlay model, the macro base station may perform wireless communication with terminal X and terminal X' in the macro area 32 using a licensed band carrier, and may be connected to a plurality of RRHs (Radio Remote Heads) through an X2 interface. Each RRH may perform wireless communication with terminal X or terminal X' within a certain area 31 using an unlicensed band carrier. Although the frequency bands of the macro base station and the RRH are different from each other, there is no mutual interference, but in order to use the NR-U service as an auxiliary downlink channel of the NR-L service through carrier aggregation, the macro base station and the RRH provide fast data through the X2 interface. exchange must be made.

In the co-located model, the pico/femto base station may perform wireless communication with the Y terminal by using the licensed band carrier and the unlicensed band carrier at the same time. However, the pico/femto base station may be limited to downlink transmission using the NR-L service and the NR-U service together. The coverage 33 of the NR-L service and the coverage 34 of the NR-U service may be different according to a frequency band, transmission power, and the like.

When NR communication is performed in the unlicensed band, existing equipment (eg, wireless LAN (Wi-Fi) equipment) communicating in the unlicensed band cannot demodulate the NR-U message or data. Therefore, the existing equipment may determine the NR-U message or data as a kind of energy and perform an interference avoidance operation by an energy detection (or detection) technique. That is, when the energy corresponding to the NR-U message or data is less than -62 dBm or a specific ED (Energy Detection) threshold, the WLAN devices may ignore the message or data and communicate. For this reason, a terminal performing NR communication in an unlicensed band may be frequently interfered with by wireless LAN equipment.

Therefore, in order to effectively implement the NR-U technology/service, it is necessary to allocate or reserve a specific frequency band for a specific time. However, since peripheral devices communicating through the unlicensed band attempt access based on the energy detection technique, there is a problem in that efficient NR-U service is difficult. Therefore, in order to establish the NR-U technology, research on a method for coexistence with existing unlicensed band devices and a method for efficiently sharing a radio channel should be preceded. That is, a strong coexistence mechanism that does not affect NR-U devices to existing unlicensed band devices should be developed.

13 shows a communication method (eg, wireless LAN) operating in an existing unlicensed band. Since most devices operating in the unlicensed band operate based on Listen-Before-Talk (LBT), a Clear Channel Assessment (CCA) for sensing a channel before data transmission is performed.

Referring to FIG. 13 , a wireless LAN device (eg, AP, STA) checks whether a channel is busy by performing carrier sensing before data transmission. When a wireless signal of a predetermined strength or higher is detected in a channel to transmit data, the corresponding channel is determined to be in use, and the wireless LAN device delays access to the corresponding channel. This process is called clear channel evaluation, and the signal level for determining whether to detect a signal is called a CCA threshold. On the other hand, when no radio signal is detected in the corresponding channel or when a radio signal having an intensity smaller than the CCA threshold is detected, it is determined that the channel is in an idle state.

If the channel is determined to be idle, the terminal having data to transmit performs a backoff procedure after a defer duration (eg, arbitration interframe space (AIFS), PIFS (PCF IFS), etc.). The dipper period means the minimum time that the UE must wait after the channel becomes idle. The backoff procedure causes the terminal to wait longer for an arbitrary amount of time after the dipper deadline. For example, the terminal waits while decreasing the slot time as much as a random number assigned to the terminal within the contention window (CW) while the channel is idle, and exhausts all the slot times. The terminal may attempt to access the corresponding channel.

Upon successful access to the channel, the terminal may transmit data through the channel. If data transmission is successful, the contention window size (CWS) is reset to an initial value (CWmin). On the other hand, if data transmission fails, the CWS is doubled. Accordingly, the UE is assigned a new random number within a double range of the previous random number range and performs a backoff procedure in the next CW. In the wireless LAN, only ACK is defined as reception response information for data transmission. Accordingly, when an ACK is received for data transmission, the CWS is reset to an initial value, and when feedback information is not received for data transmission, the CWS is doubled.

As described above, since most communication in the existing unlicensed band operates based on LBT, channel access in the NR-U system also performs LBT for coexistence with the existing device. Specifically, the channel access method on the unlicensed band in NR can be divided into the following four categories according to the presence / application of LBT.

● Category 1: No LBT

- Tx entity (entity) does not perform the LBT procedure for transmission.

● Category 2: LBT without random backoff

- The Tx entity senses whether the channel is idle during the first interval without random backoff to perform transmission. That is, the Tx entity may perform transmission through the corresponding channel immediately after the channel is sensed in the idle state during the first interval. The first interval is an interval of a preset length just before the Tx entity performs transmission. According to an embodiment, the first interval may be an interval of a length of 25 us, but the present invention is not limited thereto.

● Category 3: LBT performing random backoff using a CW of a fixed size

- The Tx entity obtains a random number within the CW of a fixed size, sets it as an initial value of a backoff counter (or backoff timer) N, and performs backoff using the set backoff counter N. That is, in the backoff procedure, the Tx entity decrements the backoff counter by 1 whenever a channel is sensed as idle for a preset slot period. Here, the preset slot period may be 9 us, but the present invention is not limited thereto. The backoff counter N is decremented by 1 from the initial value, and when the value of the backoff counter N reaches 0, the Tx entity may perform transmission. Meanwhile, in order to perform the backoff, the Tx entity first senses whether the channel is idle during the second interval (ie, the dipper period Td). According to an embodiment of the present invention, the Tx entity senses whether the channel is idle during the second interval according to whether the channel is idle for at least some period (eg, one slot period) within the second interval ( Or, you can decide). The second interval may be set based on the channel access priority class of the Tx entity, and consists of a period of 16 us and consecutive m slot periods. Here, m is a value set according to the channel access priority class. The Tx entity performs channel sensing for decrementing the backoff counter when the channel is sensed in the idle state during the second interval. Meanwhile, if the channel is sensed as being occupied during the backoff procedure, the backoff procedure is stopped. After stopping the backoff procedure, the Tx entity may resume the backoff if the channel is sensed to be idle for an additional second interval. In this way, the Tx entity may perform transmission when the channel is idle during the slot period of the backoff counter N in addition to the second interval. In this case, the initial value of the backoff counter N is obtained within a CW of a fixed size.

● Category 4: LBT performing random backoff using variable size CW

- The Tx entity obtains a random number within the variable-sized CW, sets it as the initial value of the backoff counter (or backoff timer) N, and performs backoff using the set backoff counter N. More specifically, the Tx entity may adjust the size of the CW based on HARQ-ACK information for the previous transmission, and the initial value of the backoff counter N is obtained within the CW of the adjusted size. A specific process for the Tx entity to perform backoff is the same as described in Category 3. The Tx entity may perform transmission when the channel is idle during the slot period of the backoff counter N in addition to the second interval. At this time, the initial value of the backoff counter N is obtained within the variable size CW.

In the above categories 1 to 4, the Tx entity may be a base station or a terminal. According to an embodiment of the present invention, the first type channel access may refer to category 4 channel access and the second type channel access may refer to category 2 channel access, respectively.

14 shows a channel access procedure based on Category 4 LBT according to an embodiment of the present invention.

To perform channel access, first, the Tx entity performs channel sensing for the dipper period Td (S302). According to an embodiment of the present invention, the channel sensing for the dipper period Td in step S302 may be performed through channel sensing for at least a partial period within the dipper period Td. For example, channel sensing for the dipper period Td may be performed through channel sensing for one slot period within the dipper period Td. The Tx entity checks whether the channel is in an idle state through channel sensing for the dipper period Td (S304). If the channel is sensed to be idle for the dipper period Td, the Tx entity proceeds to step S306. If the channel is not sensed to be idle (ie, sensed to be occupied) for the dipper period Td, then the Tx entity returns to step S302. The Tx entity repeats the above steps S302 to S304 until the channel is sensed as idle for the dipper period Td. The dipper period Td may be set based on the channel access priority class of the Tx entity, and consists of a period of 16 us and consecutive m slot periods. Here, m is a value set according to the channel access priority class.

Next, the Tx entity obtains a random number within the predetermined CW, sets it as an initial value of the backoff counter (or backoff timer) N (S306), and proceeds to step S308. The initial value of the backoff counter N is randomly selected from among values between 0 and CW. The Tx entity performs a backoff procedure using the configured backoff counter N. That is, the Tx entity repeats the processes of S308 to S316 until the value of the backoff counter N reaches 0 to perform the backoff procedure. Meanwhile, although FIG. 14 shows that step S306 is performed after the channel is sensed in the idle state for the dipper period Td, the present invention is not limited thereto. That is, step S306 may be performed independently of steps S302 to S304, or may be performed prior to steps S302 to S304. When step S306 is performed prior to steps S302 to S304, if the channel is sensed to be idle for the dipper period Td by steps S302 to S304, the Tx entity proceeds to step S308.

In step S308, the Tx entity checks whether the value of the backoff counter N is zero. If the value of the backoff counter N is 0, the Tx entity proceeds to step S320 to perform transmission. If the value of the backoff counter N is not 0, the Tx entity proceeds to step S310. In step S310, the Tx entity decrements the value of the backoff counter N by one. According to an embodiment, the Tx entity may selectively decrease the value of the backoff counter by 1 in the channel sensing process for each slot. In this case, step S310 may be skipped at least once according to the selection of the Tx entity. Next, the Tx entity performs channel sensing for an additional slot period (S312). The Tx entity checks whether the channel is in an idle state through channel sensing for an additional slot period (S314). If the channel is sensed to be idle for an additional slot period, the Tx entity returns to step S308. In this way, the Tx entity may decrement the backoff counter by 1 whenever a channel is sensed as idle for a preset slot period. Here, the preset slot period may be 9 us, but the present invention is not limited thereto.

In step S314, if the channel is not sensed to be idle for the additional slot period (ie, sensed to be occupied), the Tx entity proceeds to step S316. In step S316, the Tx entity checks whether the channel is idle for an additional dipper period Td. According to an embodiment of the present invention, the channel sensing in step S316 may be performed in units of slots. That is, the Tx entity checks whether the channel is sensed as idle for all slot periods of the additional dipper period Td. If an occupied slot is detected within the additional dipper period Td, the Tx entity immediately restarts step S316. If the channel is sensed to be idle for all slot periods of the additional dipper period Td, the Tx entity returns to step S308.

Meanwhile, when it is confirmed that the value of the backoff counter N is 0 in step S308, the Tx entity performs transmission (S320). The Tx entity receives the HARQ-ACK feedback corresponding to the transmission (S322). The Tx entity may check whether the previous transmission was successful through the received HARQ-ACK feedback. Next, the Tx entity adjusts the CW size for the next transmission based on the received HARQ-ACK feedback (S324).

In this way, the Tx entity may perform transmission when the channel is idle for N additional slot periods after sensing the channel as an idle state for the dipper period Td. As described above, the Tx entity may be a base station or a terminal, and the channel access procedure of FIG. 14 may be used for downlink transmission of the base station and/or uplink transmission of the terminal.

Hereinafter, a method for adaptively adjusting CWS during channel access in an unlicensed band is proposed. CWS may be adjusted based on User Equipment (UE) feedback, and UE feedback used for CWS adjustment may include HARQ-ACK feedback and CQI/PMI/RI. The present invention proposes a method for adaptively adjusting CWS based on HARQ-ACK feedback. The HARQ-ACK feedback includes at least one of ACK, NACK, DTX and NACK/DTX.

As described above, even in the WLAN system, the CWS is adjusted based on the ACK. When the ACK feedback is received, the CWS is reset to the minimum value (CWmin), and when the ACK feedback is not received, the CWS is increased. However, in a cellular system, a CWS coordination method in consideration of multiple access is required.

First, terms are defined as follows for the description of the present invention.

- A set of HARQ-ACK feedback values (ie, HARQ-ACK feedback set): means HARQ-ACK feedback value(s) used for CWS update/adjustment. The HARQ-ACK feedback set corresponds to the HARQ-ACK feedback values that are decoded and available at the time the CWS is determined. The HARQ-ACK feedback set includes HARQ-ACK feedback value(s) for one or more DL (channel) transmissions (eg, PDSCH) on an unlicensed band carrier (eg, Scell, NR-U cell). The HARQ-ACK feedback set may include HARQ-ACK feedback value(s) for DL (channel) transmission (eg, PDSCH), for example, a plurality of HARQ-ACK feedback values fed back from a plurality of terminals. The HARQ-ACK feedback value indicates reception response information for a code block group (CBG) or a transport block (TB), and may indicate any one of ACK, NACK, DTX, or NACK/DTX. Depending on the context, the HARQ-ACK feedback value may be used interchangeably with terms such as the HARQ-ACK value, the HARQ-ACK information bit, and the HARQ-ACK response.

- Reference window: refers to a time interval in which DL transmission (eg, PDSCH) corresponding to the HARQ-ACK feedback set is performed in an unlicensed band carrier (eg, Scell, NR-U cell). The reference window may be defined in units of slots or subframes according to embodiments. The reference window may point to one or more specific slots (or subframes). According to an embodiment of the present invention, a specific slot (or reference slot) may include a start slot of the most recent DL transmission burst in which at least some HARQ-ACK feedback is expected to be available.

15 shows an embodiment of a method for adjusting a contention window size (CWS) based on HARQ-ACK feedback. In the embodiment of FIG. 15 , the Tx entity may be a base station and the Rx entity may be a terminal, but the present invention is not limited thereto. In addition, although the embodiment of FIG. 15 assumes a channel access procedure for DL transmission of a base station, at least some configurations may be applied to a channel access procedure for UL transmission of a terminal.

15, after the Tx entity transmits the n-th DL transmission burst on an unlicensed band carrier (eg, Scell, NR-U cell) (S402), when additional DL transmission is required, based on LBT channel access (n +1) th DL transmission burst may be transmitted (S412). Here, the transmission burst refers to transmission through one or more adjacent slots (or subframes). 15 exemplifies a channel access procedure and a CWS adjustment method based on the above-described first type channel access (ie, category 4 channel access).

First, the Tx entity receives HARQ-ACK feedback corresponding to PDSCH transmission(s) on an unlicensed band carrier (eg, Scell, NR-U cell) (S404). The HARQ-ACK feedback used for CWS coordination includes the HARQ-ACK feedback corresponding to the most recent DL transmission burst (ie, the nth DL transmission burst) on the unlicensed band carrier. More specifically, the HARQ-ACK feedback used for CWS coordination includes the HARQ-ACK feedback corresponding to the PDSCH transmission on the reference window within the most recent DL transmission burst. The reference window may point to one or more specific slots (or subframes). According to an embodiment of the present invention, a specific slot (or reference slot) includes a start slot of the most recent DL transmission burst in which at least some HARQ-ACK feedback is expected to be available.

When the HARQ-ACK feedback is received, a HARQ-ACK value is obtained for each transport block (TB). The HARQ-ACK feedback includes at least one of a TB-based HARQ-ACK bit sequence and a CBG-based HARQ-ACK. When the HARQ-ACK feedback is a TB-based HARQ-ACK bit sequence, one HARQ-ACK information bit is obtained per one TB. On the other hand, when the HARQ-ACK feedback is a CBG-based HARQ-ACK bit sequence, N HARQ-ACK information bit(s) are obtained per one TB. Here, N is the maximum number of CBGs per TB configured for the Rx entity of PDSCH transmission. According to an embodiment of the present invention, HARQ-ACK value(s) for each TB may be determined according to HARQ-ACK information bit(s) for each TB of HARQ-ACK feedback for CWS determination. More specifically, when the HARQ-ACK feedback is a TB-based HARQ-ACK bit sequence, one HARQ-ACK information bit of the corresponding TB is determined as the HARQ-ACK value. However, if the HARQ-ACK feedback is a CBG-based HARQ-ACK bit sequence, one HARQ-ACK value may be determined based on N HARQ-ACK information bit(s) corresponding to CBGs included in the corresponding TB. .

Next, the Tx entity adjusts the CWS based on the HARQ-ACK values determined in step S404 (S406). That is, the Tx entity determines the CWS based on the HARQ-ACK value(s) determined according to the HARQ-ACK information bit(s) for each TB of the HARQ-ACK feedback. More specifically, the CWS may be adjusted based on the ratio of NACK among HARQ-ACK value(s). First, variables can be defined as follows.

-p: priority class value

- CW_min_p: preset CWS minimum value of priority class p

- CW_max_p: the preset CWS maximum value of the priority class p

- CW_p: CWS for transmission of priority class p. CW_p is set to any one of a plurality of CWS values between CW_min_p and CW_max_p included in the allowed CWS set of the priority class p.

16 is a block diagram showing the configurations of a terminal and a base station, respectively, according to an embodiment of the present invention. In an embodiment of the present invention, the terminal may be implemented as various types of wireless communication devices or computing devices that ensure portability and mobility. A UE may be referred to as User Equipment (UE), a Station (STA), or a Mobile Subscriber (MS). In addition, in an embodiment of the present invention, the base station controls and manages cells (eg, macro cells, femto cells, pico cells, etc.) corresponding to the service area, and performs signal transmission, channel designation, channel monitoring, self-diagnosis, relaying, etc. function can be performed. The base station may be referred to as a next generation node (gNB) or an access point (AP).

As shown, the terminal 100 according to an embodiment of the present invention may include a processor 110 , a communication module 120 , a memory 130 , a user interface unit 140 , and a display unit 150 . have.

First, the processor 110 may execute various commands or programs and process data inside the terminal 100 . In addition, the processor 100 may control the overall operation including each unit of the terminal 100 , and may control data transmission/reception between the units. Here, the processor 110 may be configured to perform an operation according to the embodiment described in the present invention. For example, the processor 110 may receive the slot configuration information, determine the slot configuration based on the received slot configuration information, and perform communication according to the determined slot configuration.

Next, the communication module 120 may be an integrated module that performs wireless communication using a wireless communication network and wireless LAN access using a wireless LAN. To this end, the communication module 120 may include a plurality of network interface cards (NIC), such as the cellular communication interface cards 121 and 122 and the unlicensed band communication interface card 123, in an internal or external form. . Although the communication module 120 is illustrated as an integrated integrated module in the drawing, each network interface card may be independently disposed according to a circuit configuration or use, unlike the drawing.

The cellular communication interface card 121 transmits and receives a wireless signal to and from at least one of the base station 200 , an external device, and a server using a mobile communication network, and based on a command from the processor 110 , a cellular communication service using a first frequency band can provide According to an embodiment, the cellular communication interface card 121 may include at least one NIC module using a frequency band of less than 6 GHz. At least one NIC module of the cellular communication interface card 121 independently communicates with at least one of the base station 200, an external device, and a server according to a cellular communication standard or protocol of a frequency band of less than 6 GHz supported by the corresponding NIC module. can be performed.

The cellular communication interface card 122 transmits and receives a wireless signal to and from at least one of the base station 200, an external device, and a server using a mobile communication network, and based on a command of the processor 110, a cellular communication service using a second frequency band can provide According to an embodiment, the cellular communication interface card 122 may include at least one NIC module using a frequency band of 6 GHz or higher. At least one NIC module of the cellular communication interface card 122 independently performs cellular communication with at least one of the base station 200, an external device, and a server according to a cellular communication standard or protocol of a frequency band of 6 GHz or higher supported by the corresponding NIC module. can be done

The unlicensed band communication interface card 123 transmits and receives a wireless signal with at least one of the base station 200, an external device, and a server using a third frequency band that is an unlicensed band, and based on a command of the processor 110, the Provides communication services. The unlicensed band communication interface card 123 may include at least one NIC module using the unlicensed band. For example, the unlicensed band may be a band of 2.4 GHz, 5 GHz, 6 GHz, 7 GHz, or 52.6 GHz or higher. At least one NIC module of the unlicensed band communication interface card 123 is independently or subordinately dependent on at least one of the base station 200, external device, and server according to the unlicensed band communication standard or protocol of the frequency band supported by the NIC module. Wireless communication can be performed.

Next, the memory 130 stores a control program used in the terminal 100 and various data corresponding thereto. The control program may include a predetermined program necessary for the terminal 100 to perform wireless communication with at least one of the base station 200, an external device, and a server.

Next, the user interface 140 includes various types of input/output means provided in the terminal 100 . That is, the user interface 140 may receive a user input using various input means, and the processor 110 may control the terminal 100 based on the received user input. In addition, the user interface 140 may perform an output based on a command of the processor 110 using various output means.

Next, the display unit 150 outputs various images on the display screen. The display unit 150 may output various display objects such as content executed by the processor 110 or a user interface based on a control command of the processor 110 .

In addition, the base station 200 according to an embodiment of the present invention may include a processor 210 , a communication module 220 , and a memory 230 .

First, the processor 210 may execute various commands or programs and process data inside the base station 200 . In addition, the processor 210 may control the overall operation including each unit of the base station 200 , and may control data transmission/reception between the units. Here, the processor 210 may be configured to perform an operation according to the embodiment described in the present invention. For example, the processor 210 may signal slot configuration information and perform communication according to the signaled slot configuration.

Next, the communication module 220 may be an integrated module that performs wireless communication using a wireless communication network and wireless LAN access using a wireless LAN. To this end, the communication module 220 may include a plurality of network interface cards such as the cellular communication interface cards 221 and 222 and the unlicensed band communication interface card 223 in an internal or external form. Although the communication module 220 is shown as an integrated integrated module in the drawing, each network interface card may be independently disposed according to a circuit configuration or use, unlike the drawing.

The cellular communication interface card 221 transmits/receives a wireless signal to and from at least one of the above-described terminal 100, an external device, and a server using a mobile communication network, and based on a command from the processor 210, the Communication services can be provided. According to an embodiment, the cellular communication interface card 221 may include at least one NIC module using a frequency band of less than 6 GHz. At least one NIC module of the cellular communication interface card 221 independently communicates with at least one of the terminal 100, an external device, and a server according to a cellular communication standard or protocol of a frequency band of less than 6 GHz supported by the corresponding NIC module. can be performed.

The cellular communication interface card 222 transmits and receives a wireless signal to and from at least one of the terminal 100, an external device, and a server using a mobile communication network, and based on a command of the processor 210, a cellular communication service using a second frequency band can provide According to an embodiment, the cellular communication interface card 222 may include at least one NIC module using a frequency band of 6 GHz or higher. At least one NIC module of the cellular communication interface card 222 independently performs cellular communication with at least one of the terminal 100, an external device, and a server according to a cellular communication standard or protocol of a frequency band of 6 GHz or higher supported by the NIC module. can be done

The unlicensed band communication interface card 223 transmits and receives a wireless signal with at least one of the terminal 100, an external device, and a server using a third frequency band that is an unlicensed band, and based on a command of the processor 210, the unlicensed band Provides communication services. The unlicensed band communication interface card 223 may include at least one NIC module using the unlicensed band. For example, the unlicensed band may be a band of 2.4 GHz, 5 GHz, 6 GHz, 7 GHz, or 52.6 GHz or higher. At least one NIC module of the unlicensed band communication interface card 223 is independently or dependently connected to at least one of the terminal 100, an external device, and a server according to the unlicensed band communication standard or protocol of the frequency band supported by the NIC module. Wireless communication can be performed.

The terminal 100 and the base station 200 shown in FIG. 16 are block diagrams according to an embodiment of the present invention. Separately indicated blocks are logically divided into device elements. Accordingly, the elements of the above-described device may be mounted as one chip or a plurality of chips according to the design of the device. In addition, some components of the terminal 100 , for example, the user interface 140 and the display unit 150 may be selectively provided in the terminal 100 . In addition, the user interface 140 and the display unit 150 may be additionally provided in the base station 200 as necessary.

<PUSCH scheduling - RB set and interlaced structure>

The DCI format for scheduling PUSCH may include an FDRA field for indicating frequency domain resource allocation information.

The present invention deals with an interlace indication and an RB set indication method, which are one of methods for indicating frequency domain resource allocation information.

The instruction method of Interlace is as follows.

The UE may indicate one or a plurality of interlace(s) among M interlaces. Here, M is determined according to subcarrier spacing. When the subcarrier spacing is 15 kHz, M=10, and when the subcarrier spacing is 30 kHz, M=5.

A method of indicating interlace(s) may be different according to subcarrier spacing.

If the subcarrier spacing is 30 kHz, M = 5 interlaces can be indicated by a bitmap of X = 5 bits. Each bit may indicate each interlace.

If the subcarrier spacing is 15 kHz, M interlaces may be indicated by X = 6 bits. Here, 6 bits may indicate the start index of the interlace and the number of consecutive interlaces. Here, the index of the interlace is 0, 1, … , M-1. More specifically, the value of 6 bits may be determined as a resource indication value (RIV) as follows.

thenif

then

else

Here, M is the number of interlaces, L is the number of consecutive interlaces, and m _0- is the index of the starting interlace. For reference, values not used as RIV values among 6 bits may be used to indicate combinations of other interlaces.

The RB set instruction method is as follows.

Let N be the total number of RB sets to be instructed by UL BWP. The UE may indicate the start index of the RB set and the number of consecutive RB sets as Y=ceil(log2(N*(N+1)/2)). Here, the index of the RB set is 0, 1, ... , may be N-1. More specifically, the value of Ybits may be determined as a resource indication value (RIV) as follows.

thenif

then

else

Here, N is the number of RB sets of the UL BWP, L _RBset is the number of consecutive RB sets, and RBset _START is the index of the starting RB set.

The UE may determine the frequency resource on which the PUSCH is scheduled from the X bits indicating the interlace and Y bits indicating the RB set. This may be PRBs overlapping interlace fields indicated by X bits and RB sets indicated by Y bits.

<Problem#1: DCI format & DCI size alignment background>

In the Rel-15 NR system, DCI formats of different lengths may exist as follows.

One) Fallback DCI (DCI format 0_0, 1_0) in common search space (length is expressed as DCI size A)

2) Fallback DCI (DCI format 0_0, 1_0) in UE-specific search space (length is expressed as DCI size B)

3) Non-fallback DCI scheduling PUSCH (DCI format 0_1) in UE-specific search space (length is expressed as DCI size C)

4) Non-fallback DCI scheduling PDSCH (DCI format 1_1) in UE-specific search space (length is expressed as DCI size D)

However, the UE cannot simultaneously decode four DCI formats having different lengths. The UE may decode DCI formats having up to three different lengths. Therefore, when all four lengths are different from each other, the length of some DCI format must be increased or decreased to match the length of another DCI format. To this end, in Rel-15, the steps for setting the DCI size are defined as follows.

In the 0th step, the length of the fallback DCI (DCI format 0_0, 1_0) in common search space is determined. In this case, the length of DCI format 0_0 is determined according to the size of the UL BWP, and the length of DCI format 1_0 is determined according to the size of the DL BWP. Here, the size of the DL BWP is the same as the size of the CORSEST0 if CORESET0 is configured, and the same as the size of the initial DL BWP if CORESET0 is not configured. If the length of DCI format 0_0 in common search space is greater than DCI format 1_0 in common search space, the same length by truncating the most significant bit (MSB) of the frequency domain resource assignment (FDRA) field of DCI format 0_0 in common search space make with Conversely, if the length of DCI format 0_0 in common search space is smaller than DCI format 1_0 in common search space, zero padding is performed in DCI format 0_0 in common search space to make it the same length.

After step 0, the UE can obtain the lengths of DCI format 0_0 in common search space and DCI format 1_0 in common search space, and they always have the same length. Hereinafter, this length is called DCI size A. For reference, DCI format 0_0 and DCI format 1_0 have a 1-bit delimiter (flag bit) to distinguish the two. Through this delimiter, two DCI format 0_0 and DCI format 1_0 having the same length can be distinguished.

As a first step, the length of the Fallback DCI (DCI format 0_0, 1_0) in UE-specific search space is determined. The length of DCI format 0_0 in UE-specific search space is determined according to the size of the active UL BWP, and the length of DCI format 1_0 in UE-specific search space is determined according to the size of the active DL BWP. If the length of DCI format 0_0 in UE-specific search space is greater than DCI format 1_0 in UE-specific search space, zero padding is performed on DCI format 0_0 in UE-specific search space to make it the same length. Conversely, if the length of DCI format 0_0 in common search space is smaller than DCI format 1_0 in common search space, DCI format 1_0 in common search space is zero padded to make it the same length.

After the first step, the UE can obtain the lengths of DCI format 0_0 in UE-specific search space and DCI format 1_0 in UE-specific search space, and they always have the same length. Hereinafter, this length is referred to as DCI size B. DCI size B may be the same as DCI size A. If they are the same, the UE may distinguish between DCI format 0_0/1_0 in common search space and DCI format 0_0/1_0 in UE-specific search space by using the search space. For reference, DCI format 0_0 and DCI format 1_0 have a 1-bit delimiter (flag bit) to distinguish the two. Through this delimiter, two DCI format 0_0 and DCI format 1_0 having the same length can be distinguished.

In a second step, the UE determines a non-fallback DCI (DCI format 0_1, 1_1) in UE-specific search space. The length of DCI format 0_1 in UE-specific search space is determined according to parameter values set in the active UL BWP. The length of DCI format 1_1 in UE-specific search space is determined according to the parameter values set in the active DL BWP. If the determined length of DCI format 0_1 in UE-specific search space is equal to DCI size B (DCI format 0_0/1_0 in UE-specific search space), 1-bit padding bit in DCI format 0_1 in UE-specific search space add If the determined length of DCI format 1_1 in UE-specific search space is equal to DCI size B (DCI format 0_0/1_0 in UE-specific search space), a 1-bit padding bit in DCI format 1_1 in UE-specific search space add

After the second step, the length of DCI format 0_1 in UE-specific search space is referred to as DCI size C, and the length of DCI format 1_0 in UE-specific search space is referred to as DCI size D. DCI size C and DCI size D may be the same or different. In the case of the same length, DCI format 0_1 and DCI format 1_1 have a 1-bit delimiter (flag bit) for distinguishing the two. Through this delimiter, two DCI format 0_1 and DCI format 1_1 having the same length can be distinguished. For reference, DCI size C and DCI size D can never be the same length as DCI size B.

In a third step, the UE checks whether the number of DCI formats of different lengths exceeds three. If the number of DCI formats having different lengths (DCI size A/B/C/D) does not exceed three, the UE may determine that the length of the DCI format has been successfully determined. Otherwise, the UE must perform the following additional process to set the number of DCI formats to 3 or less.

In the third step, when the number of DCI formats is 3 or less, the following are included. The first case is that DCI size A and DCI size B have the same length. In this case, regardless of the lengths of DCI format C and DCI format D, the UE has up to three DCI formats of different lengths. The second case is a case where DCI size C and DCI size D have the same length. In this case, regardless of the lengths of DCI format A and DCI format B, the UE has up to three DCI formats of different lengths. Finally, in the third case, DCI size C or DCI size D is the same as DCI size A.

An additional process for the case where there are more than three DCI format lengths in step 3 is as follows.

In the fourth step, the UE removes the 1-bit padding bit, if any, in the DCI format 0_1 in UE-specific search space or DCI format 1_1 in UE-specific search space in the second step. And the length of DCI format 0_0/1_0 in UE-specific search space is set to be the same as that of DCI format 0_0/1_0 in common search space. That is, DCI size B = DCI size A as in the first case. To this end, the length of DCI format 0_0 in UE-specific search space is made according to the size of the initial UL BWP, and the length of DCI format 1_0 in UE-specific search space is composed of CORESET0, and according to the size of CORESET0, If CORESET0 is not configured, it is created according to the initial DL BWP. And, if the length of DCI format 0_0 in UE-specific search space is greater than DCI format 1_0 in UE-specific search space, the most significant bit (MSB) of the frequency domain resource assignment (FDRA) field of DCI format 0_0 in UE-specific search space. truncate to make them the same length. Conversely, if the length of DCI format 0_0 in UE-specific search space is smaller than DCI format 1_0 in UE-specific search space, zero padding is performed in DCI format 0_0 in UE-specific search space to make it the same length.

After step 4, the UE has three different DCI sizes (DCI sizes A=B, C, D). That is, the lengths of the fallback DCI (DCI format 0_0, 1_0) in common search space and the fallback DCI (DCI format 0_0, 1_0) in UE-specific search space are the same, but DCI format 0_1 in UE-specific search space of different lengths is different. and DCI format 1_1 in UE-specific search space.

After step 4, the following cases can be determined as an error case. In the first case, DCI format 0_0 in UE-specific search space and DCI format 0_1 in UE-specific search space have the same length. In the second case, DCI format 1_0 in UE-specific search space and DCI format 1_1 in UE-specific search space have the same length. That is, when the lengths of the fallback DCI format and the non-fallback DCI format of the UE-specific search space are the same, the UE cannot distinguish the two DCI formats.

In Rel-16, a DCI format of a new length can be configured to support a new URLLC service. This is called compact DCI for convenience. The length of each field of Compact DCI can be configured through the RRC signal. Therefore, according to the configuration through the RRC signal, the compact DCI may be configured to have a shorter length of about 16 bits compared to the Rel-15 fallback DCI, may be configured to have the same length as the Rel-15 fallback DCI, and may be longer than the Rel-15 fallback DCI. It may consist of a long length. There may be two new length DCI formats as follows.

5) Compact DCI scheduling PUSCH (DCI format 0_2) in UE-specific search space (length is expressed as DCI size E)

6) Compact DCI scheduling PDSCH (DCI format 1_2) in UE-specific search space (length is expressed as DCI size F)

In order to decode the DCI formats of 1), 2), 3), 4), 5), 6) having different lengths, the UE needs to match the lengths of the DCI formats.

To this end, the length of DCI formats can be adjusted by additionally performing the following process.

Between the second and third steps, step 2A may be performed as follows.

In step 2A, the UE determines the length of compact DCI (DCI format 0_2, 1_2) in UE-specific search space. The length of DCI format 0_2 in UE-specific search space is determined according to parameter values set in DCI format 0_2 of the active UL BWP. The length of DCI format 1_2 in UE-specific search space is determined according to parameter values set in DCI format 1_2 of the active DL BWP.

In the third step, it can be checked whether the length of the DCI format of 1), 2), 3), 4), 5), 6) is within three. For example, the third step is:

In a third step, the UE checks whether the number of DCI formats of different lengths exceeds three. If the number of DCI formats having different lengths (DCI size A/B/C/D/E/F) does not exceed three, the UE may determine that the length of the DCI format has been successfully determined. Otherwise, the UE must perform the following additional process to set the number of DCI formats to 3 or less.

The fourth step may be performed as follows.

In step 4A, the UE removes the 1-bit padding bit, if any, in the DCI format 0_1 in UE-specific search space or DCI format 1_1 in UE-specific search space in the second step. And the length of DCI format 0_0/1_0 in UE-specific search space is set to be the same as that of DCI format 0_0/1_0 in common search space. That is, DCI size B = DCI size A. To this end, the length of DCI format 0_0 in UE-specific search space is made according to the size of the initial UL BWP, and the length of DCI format 1_0 in UE-specific search space is composed of CORESET0, and according to the size of CORESET0, If CORESET0 is not configured, it is created according to the initial DL BWP. And, if the length of DCI format 0_0 in UE-specific search space is greater than DCI format 1_0 in UE-specific search space, the most significant bit (MSB) of the frequency domain resource assignment (FDRA) field of DCI format 0_0 in UE-specific search space. truncate to make them the same length. Conversely, if the length of DCI format 0_0 in UE-specific search space is smaller than DCI format 1_0 in UE-specific search space, zero padding is performed in DCI format 0_0 in UE-specific search space to make it the same length.

In step 4B, if after step 4A, the UE checks whether the number of DCI formats of different lengths exceeds three. If the number of DCI formats of different lengths (DCI size A/B/C/D/E/F) exceeds three, the following is performed. The length of DCI format 0_2 in UE-specific search space is set to be the same as that of 1_2 in UE-specific search space. At this time, 0 is added until the length of the short DCI format becomes the length of the large DCI format.

In step 4C, if after step 4B, the UE checks whether the number of DCI formats having different lengths exceeds three. If the number of DCI formats of different lengths (DCI size A/B/C/D/E/F) exceeds three, the following is performed. The length of DCI format 0_1 in UE-specific search space is set to be the same as that of 1_1 in UE-specific search space. At this time, 0 is added until the length of the short DCI format becomes the length of the large DCI format.

By performing the above steps, the UE can determine up to three DCI formats of different lengths.

The length of the frequency domain resource assignment (FDRA) field of DCI format 0_0, DCI format 0_1, or DCI format 0_2 for scheduling PUSCH in the above step may not be determined according to the active UL BWP. For example, in steps 4 to 4A, the FDRA field of DCI format 0_0 in UE-specific search space may be determined according to the initial UL BWP rather than the active UL BWP. Therefore, when the UE receives DCI format 0_0 in UE-specific search space in the active UL BWP, a method of interpreting the FDRA field of the DCI format may become a problem.

If the FDRA field of DCI format 0_0, DCI format 0_1, or DCI format 0_2 for scheduling PUSCH is greater than the number of bits required in the active UL BWP, it is interpreted as resource allocation information in the frequency domain by using as many bits as necessary among the FDRA field. can

If the FDRA field of DCI format 0_0 or DCI format 0_1 or DCI format 0_2 for scheduling PUSCH is less than the number of bits required in the active UL BWP, bits of the FDRA field are used as resource allocation information in the frequency domain of the active UL BWP. It may not be enough to In the present invention, as described above, the number of bits of the FDRA field may be different for a situation where the number of bits is insufficient.

< Problem#2: BWP switch case>

In the 3GPP NR system, the UE may perform transmission/reception using a bandwidth that is less than or equal to the bandwidth of a carrier (or cell). To this end, the terminal may be configured with a bandwidth part (BWP) composed of a continuous bandwidth of a part of the bandwidth of the carrier. A UE operating according to TDD or operating in an unpaired spectrum may be configured with up to four DL/UL BWP pairs in one carrier (or cell). Also, the UE may activate one DL/UL BWP pair. A terminal operating according to FDD or operating in a paired spectrum may be configured with up to 4 DL BWPs on a downlink carrier (or cell) and up to 4 UL BWPs on an uplink carrier (or cell) can be configured. The UE may activate one DL BWP and one UL BWP for each carrier (or cell). The UE may not receive or transmit in time-frequency resources other than the activated BWP. The activated BWP may be referred to as an active BWP.

The base station may indicate the activated BWP among the BWPs configured by the terminal with downlink control information (DCI). BWP indicated by DCI is activated, and other configured BWP(s) are deactivated. In a carrier (or cell) operating in TDD, the base station may include a bandwidth part indicator (BPI) indicating the activated BWP in DCI scheduling PDSCH or PUSCH to change the DL/UL BWP pair of the terminal. The UE may receive a DCI scheduling a PDSCH or a PUSCH and identify an activated DL/UL BWP pair based on the BPI. In the case of a downlink carrier (or cell) operating in FDD, the base station may include the BPI indicating the activated BWP in the DCI scheduling the PDSCH to change the DL BWP of the terminal. In the case of an uplink carrier (or cell) operating in FDD, the base station may include the BPI indicating the activated BWP in the DCI scheduling the PUSCH to change the UL BWP of the terminal.

A different number of RBs, RB sets, and different numerology (subcarrier spacing and CP type) may be configured for each BWP. The length of the FDRA field included in the DCI format may vary depending on the number of RBs, the number of RB sets, or subcarrier spacing. Therefore, the length of the FDRA field included in the DCI format for scheduling PDSCH or PUSCH in different BWPs may be different.

In the NR system, the UE may obtain the length of the FDRA field according to RBs, RB sets, and subcarrier spacing of the active UL BWP, and monitor the DCI format including the FDRA field. In other words, when the BPI of the DCI format for scheduling the PUSCH activates a UL BWP other than the active UL BWP, the number of bits of the FDRA field may not match the UL BWP activated by the BPI.

For example, if the active UL BWP is 30 kHz, the FDRA field may include X=5 bits to indicate the interlace of the active UL BWP. When BPI of DCI format activates UL BWP with subcarrier spacing of 15 kHz, X=6 bits are required to indicate the interlace of the UL BWP. Therefore, 1 bit may be insufficient.

For example, if the active UL BWP includes N RB sets, the FDRA field may include Y=ceil(log2(N*(N+1)/2)) bits to indicate the RB set of the active UL BWP. have. When the BPI of the DCI format activates the UL BWP in which the number of RB sets is N', Y=ceil(log2(N'*(N'+1)/2)) bits are required to indicate the RB set of the UL BWP. do. Therefore, when N' is greater than N, bits may be insufficient.

<Example: X & Y truncation>

It is assumed that the UE needs Z=(X+Y) bits for the length of the FDRA field for resource allocation in the frequency domain. Here, X may indicate one or more interlaces. If the subcarrier spacing of UL BWP is 15kHz, it may be X=6 bits, and if it is 30kHz, it may be X=5 bits. Y may indicate one or a plurality of RB sets among RB sets of UL BWP. If the UL BWP includes M RB sets, it may be Y=ceil(log2(M*(M+1)/2)) bits.

The UE may have a length of the FDRA field less than Z bit(s). This may be a result of the aforementioned base station reducing the length of the FDRA field for DCI size alignment. Let the length of the FDRA field actually received by the terminal through DCI transmitted from the base station be Z' bit. In other words, Z' < Z. In this case, the UE may use X' bits of Z' to indicate one or more interlaces, and Y' bits to indicate one or a plurality of RB sets among RB sets constituting the UL BWP. Here, X'+Y'=Z', and a method of obtaining X' and Y' among Z' bits, an interpretation method of the X' bit, and an interpretation method of Y' are required. For reference, if X'=X, the method of indicating one or more interlaces can be used as it is. Also, for reference, if Y'=Y, a method of indicating one or a plurality of RB sets among RB sets constituting the UL BWP may be used as it is. Therefore, an additional analysis method is required only when X'<X or Y'<Y.

In an embodiment of the present invention, a method of obtaining X' and Y' among Z' bits is as follows.

- The UE can make Y' bits by maintaining X'=X and truncating Y bits. Here, Y' bits can be made by truncating from Y bits as much as (Z-Z') bits. If (Z-Z') bits are greater than Y bits (ie, (Z-Z') > Y), Y bits become 0 bits, and X bits can be additionally truncated. Here, from X bits to (Z-Z'-Y) bits can be truncated.

- The UE can make X' bits by maintaining Y'=Y and truncating X bits. Here, X' bits can be made by truncating from X bits as much as (Z-Z') bits. If (Z-Z') bits are greater than X bits (ie, (Z-Z') > X), X bits become 0 bits, and Y bits can be additionally truncated. Here, in Y bits, as many as (Z-Z'-X) bits can be truncated.

- The UE may truncate X bits by n bit(s) to make X' bits, and truncate Y bits by k bit(s) to make Y' bits. where Z-Z'=n+k. By finding non-negative integers n and k, Z-Z' can be divided into n and k as evenly as possible. For example, at least one of n = floor((Z-Z')/2) or n = ceil((Z-Z')/2) or n = round((Z-Z')/2) can be set as k = Z-Z'-n.

The above truncation may be performed on the most significant bit (MSB) of each DCI field (each of X bits and Y bits). When truncation is performed in the MSB of X bits, it can be interpreted as indicating one or more interlaces after making X bits by adding zeros of X-X' bits to the MSB of X' bits. When truncation is performed in the MSB of Y bits, zeros of YY' bits are added to the MSB of Y' bits to make Y bits, and then interpreted as indicating one or a plurality of RB sets among the RB sets constituting the UL BWP. can

<Example: X bits truncation, X'<X situation>

According to an embodiment of the present invention, in a situation where some of the X bits are truncated and are X' bits, the X' bits may be interpreted as follows.

The UE can make an interlace group by tying the interlaces together. Each interlace group can be indicated by X' bits. Here, when tying interlaces, adjacent interlaces can be tied. Here, adjacent means adjacent in the frequency domain.

X'<ceil(log2((N+1)*(N+2)/2)을 만족하는 N 값이 X' bits으로 지시할 수 있는 interlace group의 최대 수이다. 참고로 X'6 bits이면, N=10이다. 그러므로 10개의 interlace는 별도의 interlace group 없이 X'=6 bits으로 지시할 수 있다. X'=5 bits이면 N =7이다. 그러므로, 10개의 interlace는 7개의 interlace group으로 묶어서 각 group의 index가 X'=5 bits으로 지시될 수 있다. X'=4 bits이면 N =5이다. 그러므로, 10개의 interlace는 5개의 interlace group으로 묶어서 각 group의 index가 X'=4 bits으로 지시될 수 있다. X'=3 bits이면 N =3이다. 그러므로, 10개의 interlace는 3개의 interlace group으로 묶어서 각 group의 index가 X'=3 bits으로 지시될 수 있다. X'=2 bits이면 N=2이다. 그러므로, 10개의 interlace는 2개의 interlace group으로 묶어서 각 group의 index가 X'=2 bits으로 지시될 수 있다. X'=1 bit 또는 X'=0 bit이면 N=1이다. 그러므로, 10개의 interlace는 1개의 interlace group으로 묶어서 각 group의 index가 X'=1 bit 또는 X'=0 bit으로 지시될 수 있다.- In case of 15kHz subcarrier spacing, the number of interlace groups that can be indicated by X' bits can be determined. ceil(log2(N*(N+1)/2)

N value satisfying X'<ceil(log2((N+1)*(N+2)/2) is the maximum number of interlace groups that can be indicated by X' bits. For reference, if X'6 bits, N = 10. Therefore, 10 interlaces can be indicated by X' = 6 bits without a separate interlace group. If X' = 5 bits, N = 7. Therefore, 10 interlaces are grouped into 7 interlace groups and each The index of a group can be indicated by X' = 5 bits If X' = 4 bits, N = 5. Therefore, 10 interlaces are grouped into 5 interlace groups, and the index of each group is indicated by X' = 4 bits. If X' = 3 bits, N = 3. Therefore, 10 interlaces are grouped into 3 interlace groups, so that the index of each group can be indicated by X' = 3 bits. If X' = 2 bits, N = 3. = 2. Therefore, ten interlaces are grouped into two interlace groups, so that the index of each group can be indicated by X' = 2 bits. If X' = 1 bit or X' = 0 bit, then N = 1. Therefore, , 10 interlaces are grouped into one interlace group, so that the index of each group may be indicated by X'=1 bit or X'=0 bit.

- In the case of 30kHz subcarrier spacing, the number of interlace groups that can be indicated by X' bits can be determined. The UE can make X' interlace groups by bundling 5 interlaces, and each interlace group among X' interlace groups is indicated when each bit of X' bits is 1. Each interlace group among X' interlace groups is not indicated if each bit of X' bits is 0.

- The method of grouping A interlaces into B interlace groups is as follows. As an embodiment, the UE may form one interlace group by bundling ceil (A/B) interlaces. In this way, B-1 interlace groups are made, and the last interlace group may have an interlace of A - ceil(A/B)*(B-1). In another embodiment, ceil (A/B) interlaces are bundled to form B mod A interlace groups, and floor (A/B) interlaces are bundled to form B - (B mod A) interlace groups. When bundling the interlace into an interlace group, if possible, adjacent interlaces in a frequency band may be bound to the interlace group. As another example, an interlace that is far away from the frequency band if possible can be bundled into an interlace group.

In another embodiment, when grouping interlaces, in order to obtain maximum frequency diversity, interlaces as far away from a frequency band as possible may be bundled. For example, when there are 10 interlaces, if X' = 4 bits is smaller than X = 6 bits, so that resource allocation to 5 interlace groups must be performed by configuring an interlace group, the interlace index is { When there are 10 interlaces such as 0,1,2,3,4,5,6,7,8,9}, the interlace groups are {0,5}, {1,6}, (2,7 ), {3,8}, {4,9} to configure 5 groups so that interlaces far away on the frequency band can be grouped if possible, and resource allocation is performed according to the corresponding X' bits from the base station to the terminal This can be done to receive.

In an embodiment of the present invention, in the process of adjusting the length of the DCI format to a maximum of three, the bits of the FDRA field may be determined as follows.

In steps 4 to 4A of the process of adjusting the length of the DCI format to a maximum of three, a process of adjusting the length of DCI format 0_0 in UE-specific search space to DCI format 0_0/1_0 in common search space is performed. In this process, the length of the FDRA field of DCI format 0_0 in UE-specific search space may be determined according to the initial UL BWP rather than the active UL BWP. The UE needs 6 bits if the active UL BWP is 15 kHz and 5 bits if the X bits of the FDRA field of the DCI format 0_0 in UE-specific search space is 15 kHz to indicate the interlace of the active UL BWP. And, the UE needs ceil(log2(N*(N+1)/2)) bits for Y bits of the FDRA field of the DCI format 0_0 in UE-specific search space to indicate the RB set of the active UL BWP. Here, N is the number of RB sets of the active UL BWP. However, in steps 4 to 4A, X bits of the FDRA field of DCI format 0_0 in UE-specific search space are the same as the number of bits for indicating the interlace of the initial UL BWP. For example, if the initial UL BWP is 15kHz, it is 6bits, and if it is 30kHz, it is 5bits. In steps 4 to 4A, Y bits of the FDRA field of DCI format 0_0 in UE-specific search space are ceil(log2(N'*(N'+1)/2)) bits to indicate the RB set of the initial UL BWP. is needed Here, N' is the number of RB sets of the initial UL BWP.

For example, if active UL BWP is 15kHz, X=6bits are required to receive interlace of active UL BWP, but if initial UL BWP is 30kHz, X'=5bits, which is the number of bits for indicating interlace of initial UL BWP, exists. do.

To solve this, the UE may obtain the X bits of the FDRA field of the DCI format 0_0 in UE-specific search space in steps 4 to 4A as subcarrier spacing of the active UL BWP. That is, the X bits of the FDRA field of DCI format 0_0 in UE-specific search space are 6 bits when the active UL BWP is 15 kHz, and 5 bits when the active UL BWP is 30 kHz.

As such, when the length of X bits of the FDRA field of DCI format 0_0 in UE-specific search space in steps 4 to 4A is obtained as the subcarrier spacing of active UL BWP, the length of the FDRA field of DCI format 0_0 in UE-specific search space ( That is, both Xbits and Ybits) may be smaller or larger than DCI format 0_0/1_0 in common search space. In order to align with the same length, some bits of Y bits may be truncated or some bits may be added.

<Example: Y bits truncation, Y'<Y situation>

In an embodiment of the present invention, the terminal has a bit size indicating the RB set in the FDRA field of the DCI format for uplink transmission received from the base station, one of the RB sets constituting the UL BWP or all combinations of a plurality of RB sets. If it is smaller than the bit size required for indication, the following operation can be performed. For convenience, a bit size indicating one or a plurality of RB sets among the RB sets in the FDRA field of the DCI format received by the terminal from the base station is Y', and one or more of the RB sets constituting the UL BWP is Let Y be the bit size required to indicate all combinations. As mentioned earlier, Y = ceil(log2(N*(N+1)/2)). Here, N is the number of RB sets constituting the UL BWP in which the uplink channel is scheduled. Exemplarily, Y' bits are determined as follows.

- Method 1 (UL BWP switch): When the DCI format includes an indication of an active UL BWP change of the UE, Y' bits are determined based on the UL BWP before the change. More specifically, Y' bits are Y' = ceil(log2(N'*(N'+1)/2)). Here, N' is the number of RB sets included in the UL BWP before the change.

- Method 2 (DCI size alignment): The length of each DCI field may be truncated for DCI size alignment in the DCI format. In this case, Y' bits are values determined according to DCI size alignment.

The present invention deals with a case in which the Y' bits determined as in the above two methods are smaller than the required Y bits. An embodiment of the present invention can be applied without separately distinguishing the two methods. If separate classification is required, separate examples for each method may be included.

The UE may determine the RB set(s) of the UL BWP for uplink transmission based on the RB set that has received the uplink DCI format among one or a plurality of RB sets of the DL BWP. The UE may determine in which RB set the DCI format was received by using the frequency allocation information of the CORESET from which the DCI format was received and the frequency allocation information of the RB set(s) of the DL BWP. The UE may determine one or more RB set(s) among the RB set(s) of the UL BWP by using the determined RB set of the DL BWP. Here, the RB set of the UL BWP may be an RB set(s) that completely or partially overlaps the determined RB set of the DL BWP. Let this RB set be called an overlapping RB set. If there is no RB set of UL BWP overlapping with the determined RB set of DL BWP. In this case, it is said that there is no overlapping RB set.

- If the CORESET from which the terminal has received the DCI format overlaps the RB sets of a plurality of DL BWPs, the terminal may determine one RB set among the plurality of RB sets using frequency information. For example, the RB set having the lowest frequency may be determined as the RB set receiving the DCI format. For example, the RB set having the highest frequency may be determined as the RB set receiving the DCI format. For example, it is possible to determine an RB set that has the largest overlap between the CORESET receiving the DCI format and the frequency domain as the RB set receiving the DCI format.

As another method, the UE may determine the RB set(s) of the UL BWP for uplink transmission based on the CORESET that has received the DCI format. The UE uses the frequency allocation information of the CORESET from which the DCI format is received and the frequency allocation information of the RB set(s) of the UL BWP, one or more RB(s) sets overlapping the CORESET among the RB set(s) of the UL BWP. can be determined. Here, the RB set of the UL BWP may be an RB set(s) overlapping the determined CORESET. Let this RB set(s) be called overlapping RB set. If there is no RB set of UL BWP overlapping with the determined RB set of DL BWP. In this case, it is said that there is no overlapping RB set.

- If the CORESET from which the terminal has received the DCI format overlaps the RB sets of the plurality of UL BWPs, the terminal may determine one RB set among the plurality of RB sets using frequency information. For example, the RB set having the lowest frequency may be determined as the RB set overlapping the CORESET. For example, the RB set having the highest frequency may be determined as the RB set overlapping the CORESET. For example, it is possible to determine the RB set that overlaps the CORESET that has received the DCI format the most in the frequency domain as the RB set that overlaps the CORESET.

As another method, the UE may determine the RB set(s) of the UL BWP for uplink transmission based on the control channel element (CCE) or resource element group (REG) or PRBs of the PDCCH receiving the DCI format. . The UE uses the information of CCE/REG/PRB of the PDCCH in which the DCI format is received and the frequency allocation information of the RB set(s) of the UL BWP to overlap the PDCCH receiving the DCI format among the RB set(s) of the UL BWP. One or more RB set(s) may be determined. Here, the RB set(s) of the UL BWP may be the RB set(s) overlapping the determined PDCCH. Let this RB set(s) be called overlapping RB set. If there is no RB set of UL BWP overlapping with the determined RB set of DL BWP. In this case, it is said that there is no overlapping RB set.

- When the PDCCH on which the terminal has received the DCI format overlaps the RB sets of the plurality of UL BWPs, the terminal may determine one RB set among the plurality of RB sets using frequency information. For example, the RB set having the lowest frequency may be determined as the RB set overlapping the PDCCH. For example, the RB set having the highest frequency may be determined as the RB set overlapping the PDCCH. For example, it is possible to determine the RB set that overlaps the most with the PDCCH receiving the DCI format in the frequency domain as the RB set overlapping the PDCCH.

If there is no overlapping RB set, the terminal indicates that the bits (Y' bits) indicating the RB set in the FDRA field of the received DCI format are one or a plurality of RB set(s) among the RB set(s) of the UL BWP. can be determined to be directed. The specific method is as follows.

n In an embodiment of the present invention, the terminal selects at least one value among the bits (Y' bits) indicating the RB set in the FDRA field of the received DCI format from among the RB sets of the UL BWP, but the most in the frequency domain. It can be determined to indicate a low RB set. The index of the RB set of the UL BWP may be assigned in ascending order of frequency. In this case, the UE may determine that at least one value among bits (Y' bits) indicating the RB set in the FDRA field of the received DCI format indicates RB set #0 of the UL BWP. In addition, the UE determines that at least one value of bits (Y' bits) indicating the RB set in the FDRA field of the received DCI format indicates the highest RB set in the frequency domain among the RB sets of the UL BWP. can do.

n In an embodiment of the present invention, the terminal selects at least one value among bits (Y' bits) indicating the RB set in the FDRA field of the received DCI format from among the RB sets of the UL BWP, but in the DL BWP, DCI It can be determined that the format is indicated by the RB set closest to the received RB set. Here, proximity may be defined in the frequency domain. For example, among the (center, lowest, or highest) frequencies of the RB sets of the UL BWP, the RB set closest to the (center, lowest, or highest) frequency of the RB set that received the DCI format in the DL BWP is selected It can be determined as directed. For reference, when there are a plurality of nearest RB sets, the UE may determine an RB set having a low frequency. Alternatively, when there are a plurality of nearest RB sets, the UE may determine an RB set having a high frequency.

n In an embodiment of the present invention, the terminal selects at least one value among bits (Y' bits) indicating the RB set in the FDRA field of the received DCI format from among the RB sets of the UL BWP, but the RB of the DL BWP It can be determined to indicate one of the overlapping RB sets among the sets. Here, if there are a plurality of RB sets of UL BWP overlapping RB sets of DL BWP among RB sets of UL BWP, it may be determined that the RB set of UL BWP having the lowest frequency among them is indicated. Also, if there are a plurality of RB sets of UL BWP overlapping RB sets of DL BWP among RB sets of UL BWP, it may be determined that the RB set of UL BWP having the highest frequency among them is indicated.

n In an embodiment of the present invention, in the case of method 1 (UL BWP switch), the terminal changes the value of at least one of bits (Y' bits) indicating the RB set in the FDRA field of the received DCI format after changing the UL BWP It can be selected from among the RB sets of , but it can be determined to indicate one of the overlapping RB sets among the RB sets of the UL BWP before the change. Here, among the RB sets of the UL BWP after the change, if there are a plurality of RB sets of the UL BWP after the change overlapping the RB sets of the UL BWP before the change, the RB set of the UL BWP after the change with the lowest frequency is indicated. can be judged. In addition, among the RB sets of the UL BWP after the change, if there are a plurality of RB sets of the UL BWP after the change overlapping the RB sets of the UL BWP before the change, the RB set of the UL BWP after the change with the highest frequency is indicated. can be judged.

When there is an overlapping RB set, the UE may determine that at least one value among bits indicating the RB set in the FDRA field of the received DCI format indicates the overlapping RB set. If the overlapping RB set includes a plurality of RB sets, one RB set may be determined as follows.

n In an embodiment of the present invention, if the overlapping RB set includes a plurality of RB sets, one RB set may be selected based on frequency information of the plurality of RB sets. For example, an RB set having the lowest frequency information may be selected. Also, an RB set having the highest frequency information may be selected.

n In an embodiment of the present invention, if the overlapping RB set includes a plurality of RB sets, one RB set may be selected based on frequency information of the plurality of RB sets and frequency information of the PDCCH through which the DCI format is transmitted. For example, from among the plurality of RB sets, the RB set that overlaps the most in the frequency domain with the PDCCH through which the DCI format is transmitted may be selected. As another example, among the plurality of RB sets, an RB set overlapping (or closest to) a specific frequency of the PDCCH on which the DCI format is transmitted may be included. For example, among the plurality of RB sets, the DCI format may include an RB set overlapping (or closest to) an RB having the lowest frequency of the transmitted PDCCH. Alternatively, it may include an RB set that overlaps (or is closest to) an RB of the highest frequency of the PDCCH through which the DCI format is transmitted among the plurality of RB sets.

n In an embodiment of the present invention, if the overlapping RB set includes a plurality of RB sets, one RB set may be selected based on frequency information of the plurality of RB sets and frequency information of the RB set to which the DCI format is transmitted. For example, from among the plurality of RB sets, the RB set in which the DCI format is transmitted and the RB set that overlap the most in the frequency domain may be selected. As another example, among the plurality of RB sets, an RB set overlapping (or closest to) a specific frequency of the RB set to which the DCI format is transmitted may be included. For example, among the plurality of RB sets, an RB set overlapping (or closest to) an RB having the lowest frequency of the RB set in which the DCI format is transmitted may be included. Alternatively, it may include an RB set that overlaps (or is closest to) an RB of the highest frequency of the RB set to which the DCI format is transmitted among the plurality of RB sets.

The UE, through the above embodiment, refers to the RB set of the UL BWP that can be indicated by at least one value among bits (Y' bits) indicating the RB set in the FDRA field of the received DCI format as the designated RB set. lets do it.

In the FDRA field of the DCI format received by the UE, the number of combinations of RB set(s) that can be indicated according to the length of bits (Y' bits) indicating the RB set may be determined. If the length of bits (Y' bits) indicating the RB set in the FDRA field of the received DCI format is 0 bits, the terminal can always determine that it indicates the specified RB set. For example, when Y' = 2 bits, the 2 bits may have values of 00, 01, 10, and 11. Therefore, when Y'=2 bits is given, a combination of up to four RB set(s) may be indicated. In general, when a Y' bit is given, a combination of up to 2^Y' RB set(s) may be indicated. One of the 2^Y' RB set(s) combinations may indicate the designated RB set. A method of determining the remaining 2^Y'-1 RB set(s) combinations is as follows.

- In an embodiment of the present invention, a combination of 2^Y' RB set(s) indicated by Y' bits may be determined as follows. First, the terminal may select the designated RB set and RB sets of the UL BWP adjacent to the designated RB set. The combination of 2^Y' RB set(s) indicated by Y' bits is a combination of adjacent RB sets among the RB sets of the UL BWP thus selected. Here, adjacency is defined in the frequency domain. RB sets indicated by a combination of 2^Y' RB set(s) are not separated from each other in the frequency domain. The Y' bit may indicate a designated RB set and adjacent RB sets among RB sets adjacent to the designated RB set in the frequency domain. A combination of 2^Y' RB set(s) may indicate a designated RB set and adjacent RB set(s) used for uplink among the designated RB sets and adjacent RB sets in the frequency domain. The designated RB set may be determined through the previous embodiment. However, there is a need for a method of obtaining an RB set adjacent to the designated RB set by frequency. Specifically, a method of determining the order of RB sets according to the proximity is as follows.

n In an embodiment of the present invention, the order of the RB sets that can be indicated by the combination of 2^Y' number of RB set(s) indicated by Y' bits is among the designated RB set and the RB sets having a higher frequency than the designated RB set. This is the order of the RB sets closest to the designated RB set. For example, suppose that the index of the RB set of the UL BWP is given as RB set #0, RB set #1, RB set #2, and RB set #3 in ascending order according to frequency. If the designated RB set is RB set #1, among RB sets having a higher frequency than the designated RB set, the RB set closest to the designated RB set is RB set #2, followed by RB set #3. However, since RB set #0 is at a lower frequency than RB set #1, it is not included in the combination of 2^Y' RB set(s).

n In an embodiment of the present invention, the order of RB sets that can be indicated by a combination of 2^Y' number of RB set(s) indicated by Y' bits is among the designated RB set and the RB sets having a lower frequency than the designated RB set. This is the order of the RB sets closest to the designated RB set. For example, suppose that the index of the RB set of the UL BWP is given as RB set #0, RB set #1, RB set #2, and RB set #3 in ascending order according to frequency. If the designated RB set is RB set #1, the RB set closest to the designated RB set among RB sets having a lower frequency than the designated RB set is RB set #0. However, RB set #2 and RB set #3 are not included in the combination of 2^Y' RB set(s) because they are at a higher frequency than RB set #1.

n In an embodiment of the present invention, the order of the RB sets that can be indicated by the combination of 2^Y' number of RB set(s) indicated by Y' bits is among the designated RB set and the RB sets having a higher frequency than the designated RB set. It is the order of the RB sets closest to the designated RB set, and then the order of the RB sets closest to the designated RB set among RB sets having a lower frequency than the designated RB set. For example, suppose that the index of the RB set of the UL BWP is given as RB set #0, RB set #1, RB set #2, and RB set #3 in ascending order according to frequency. If the designated RB set is RB set #1, among RB sets having a higher frequency than the designated RB set, the RB set closest to the designated RB set is RB set #2, followed by RB set #3. Next is RB set #0 at a lower frequency than RB set #1.

n In an embodiment of the present invention, the order of RB sets that can be indicated by a combination of 2^Y' number of RB set(s) indicated by Y' bits is among the designated RB set and the RB sets having a lower frequency than the designated RB set. It is the order of the RB sets closest to the designated RB set, and then the order of the RB sets closest to the designated RB set among RB sets having a higher frequency than the designated RB set. For example, suppose that the index of the RB set of the UL BWP is given as RB set #0, RB set #1, RB set #2, and RB set #3 in ascending order according to frequency. If the designated RB set is RB set #1, the RB set closest to the designated RB set among RB sets having a lower frequency than the designated RB set is RB set #0. Next, RB set #2 at a higher frequency than RB set #1 is the most adjacent RB set, and then RB set #4 is the most adjacent RB set.

n In an embodiment of the present invention, the combination of 2^Y' number of RB set(s) indicated by Y' bits is a combination of the designated RB set and the RB sets close to the frequency of the designated RB set. For example, the frequency may include at least one of the center frequency of the RB set, the lowest frequency of the RB set, and the highest frequency of the RB set. When there are a plurality of RB sets closest to the designated RB set, the UE may select one of them according to the frequency of the RB set. For example, it may be determined that the lower frequency of the RB set is closer. For example, it may be determined that the higher frequency of the RB set is closer. For example, suppose that the index of the RB set of the UL BWP is given as RB set #0, RB set #1, RB set #2, and RB set #3 in ascending order according to frequency. Each RB set occupies 20 MHz, and let's use the center frequency as the frequency. If the designated RB set is RB set #1, the RB sets closest to the designated RB set are RB set#0 and RB set#2. The UE may determine one of the two RB set #0 and RB set #2 as the closer RB set. For example, it may be determined that the frequencies of the two RB sets are lower and are closer. In this case, the RB set closest to the designated RB set is RB set #0, and the next closest RB set is RB set #2. And the last closest RB set is RB set #3. According to an example, in this embodiment, the order of the closest RB set of a low frequency and the closest RB set of a high frequency is alternately ordered with respect to a designated RB set.

- In the above embodiment, the order according to the adjacency of the RB sets included in the combination of 2^Y' RB set(s) indicated by the Y' bits was determined. The UE may select RB sets based on the order according to the contiguous sum. The maximum number of RB set(s) included in the combination (hereinafter referred to as M) may be determined according to Y'. The UE may determine M RB sets included in a combination of 2^Y' RB set(s). Here, one of the M RB sets is necessarily a designated RB set, and the other (M-1) RB sets are RBs adjacent to the designated RB set.

n For example, when Y'=2 bits, the UE may include up to M=2 RB sets. This is ceil(log2(M*(M+1)/2))= ceil(log2(2*(2+1)/2))=2, which is less than or equal to Y'=2, but M =3 RB sets. In the case of ceil(log2(M*(M+1)/2))=ceil(log2(3*(3+1)/2))=3, this is because Y'=2. In general, the maximum number M of RB set(s) that can be expressed by Y' bits is the largest value among integer M values satisfying ceil(log2(M*(M+1)/2))?Y'.

n For example, in the case of method 1 (UL BWP switch), M may be determined as the number of RB sets included in the UL BWP before the change. As already mentioned, in the case of method 1 (UL BWP switch), since Y' is determined as ceil(log2(M*(M+1)/2)), the Y' bit is used for scheduling among M RB sets. It may indicate adjacent RB sets to be used.

In an embodiment of the present invention, when the terminal has a bit size (Y' bit) indicating the RB set in the FDRA field of the received DCI format is smaller than the bit size (Y bit) required to indicate the RB set of the UL BWP, When all Y' bits are 0, the UE may determine that it indicates a designated RB set. If all Y' bits are not 0, it can be interpreted as follows.

- In the first embodiment, Y bits are made by padding 0s of Y-Y' bits to most significant bits (MSBs) in Y' bits. By interpreting the Y bits as Y bits indicating the RB set of the UL BWP, the indicated RB set(s) among the RB set(s) of the UL BWP may be determined.

- In the second embodiment, let M virtual RB set(s) be virtual RB-set #0, virtual RB-set #1, ??, and virtual RB-set #(M-1). Here, M may be one of integer M values satisfying ceil(log2(M*(M+1)/2))?Y'. It may be set to the largest value. It is possible to determine the indicated virtual RB set(s) from among the M virtual RB set(s) with Y' bits. The actually scheduled RB set may be determined by considering index 0 of the virtual RB set determined as indicated by the Y' bit as the designated RB set. For example, it is determined that virtual RB-set #1 and virtual RB-set #2 are indicated by Y' bit, and it is assumed that the designated RB set is RB set #1 of UL BWP. In this case, RB set #1 of UL BWP, which is a designated RB set, is regarded as virtual RB-set #0, so virtual RB-set#1 is RB set #2 of UL BWP, and virtual RB-set#2 is of UL BWP. This is RB set #3.

The above embodiment may be selectively used depending on the situation. Exemplarily, when the bit size (Y' bit) indicating the RB set in the FDRA field of the received DCI format is smaller than the bit size (Y bit) required to indicate the RB set of the UL BWP, the terminal is among the Y' bits. If all values do not indicate the designated RB set, the terminal may determine that the Y' bit is a specific value, indicating that the terminal indicates the designated RB set. A more specific example is as follows.

- Y bits are made by padding 0 of Y-Y' bits to the most significant bit (MSB). By interpreting the Y bits as Y bits indicating the RB set of the UL BWP, the indicated RB set(s) among the RB set(s) of the UL BWP may be determined. The Y bits may represent a combination of a maximum of 2^Y RB set(s), but since YY' MSB is fixed to 0, it may represent only a maximum of 2^Y' values, and 2^Y' RB set(s) ( ) can represent a combination. Therefore, the designated RB set may or may not be included among the combinations of 2^Y' RB set(s). Therefore, when the designated RB set is not included in the combination of RB set(s), the UE may interpret one of 2^Y' values as indicating the designated RB set. This value may be a case where all Y' values are 0. Alternatively, this value may be a case where all Y' values are 1.

Possible combinations according to embodiments of the present invention are described below.

Scenario 1: One of the scenarios considered in the present invention. Referring to FIG. 17, the UE sets four RB sets (RB set #0, RB set #1, RB set #2, RB set #3) in the DL BWP. UL BWP #A includes one RB set (RB set #0 in UL BWP #A), and UL BWP #B includes four RB sets (RB set #0 in UL BWP #B, RB set #1 in UL BWP #B, RB set #2 in UL BWP #B, RB set #3 in UL BWP #B). Here, the index of the RB set is determined according to each BWP (BWP-specific). The UE may receive the DCI format in one RB set (eg, RB set #3) of the DL BWP. Here, the DCI format may indicate to change the active UL BWP from UL BWP #A to UL BWP #B, and may schedule PUSCH to UL BWP #B. The DCI format may include Y' bits for indicating the RB set of UL BWP #A before the UL BWP change. Since UL BWP #A includes one RB set, Y' = ceil(log2(1*2/2)) = 0 bit. Accordingly, Y'=0 bit is included in the DCI format to indicate the RB set. However, since the UL BWP includes 4 RB sets after the change in which the PUSCH is scheduled, Y = ceil(log2(4*5/2))=4 to indicate the RB sets in which the PUSCH is scheduled among the 4 RB sets. bits are required. Therefore, it is a situation where Y' < Y. For reference, in this scenario, with 2^Y' = 1, the UE may be instructed with only one designated RB set combination with Y'=0 bit of the DCI format.

Possible Combination 1-1: After the change, the UE checks whether there is an overlapping RB set in the frequency domain with RB set #3 to which DCI format is transmitted among RB sets of UL BWP #B. Referring to FIG. 17 , RB set #3 in UL BWP #B is an overlapping RB set in the frequency domain. Therefore, it can be determined that the RB set in UL BWP #B is a designated RB set. In this case, when the base station succeeds in channel access to one or more specific RB set(s) on the unlicensed band, the COT (Channel Occupancy Time) set by the base station for the RB set(s) is shared to the terminal, and the terminal By simplifying the channel access of , it is possible to increase the uplink transmission probability in terms of channel access. That is, when the terminal wants to transmit within the COT (Channel Occupancy Time) that the base station sets and can indicate to the terminal through group common signaling, the terminal performs random back-off in a channel access method by sharing the COT from the gNB to the terminal. It can have the advantage of increasing the possibility of UL transmission through a simple Cat-2 method (a channel access method performing channel access for a single interval) or a No LBT method rather than a Cat-4 channel access method.

Possible combinations 1-2: In possible combinations 1-1, DCI format was received in RB set #3. And before the change, the RB set of the UL BWP overlapped with the RB set #3. According to an embodiment of the present invention, the designated RB set may be determined using frequency domain information of the RB set of the UL BWP before the change. Referring to FIG. 18 , the UE may receive DCI format in RB set #1 of DL BWP. RB set #1 of this DL BWP does not overlap with the RB set of the UL BWP before the change. In this case, it is checked whether there is an overlapping RB set in the frequency domain with RB set #1 to which DCI format is transmitted among RB sets of UL BWP #B after the change. RB set #1 in UL BWP #B is an overlapping RB set in the frequency domain. Therefore, it can be determined that the RB set #1 in UL BWP #B is a designated RB set. In this case, when the base station succeeds in channel access to one or more specific RB set(s) on the unlicensed band, the COT (Channel Occupancy Time) set by the base station for the RB set(s) is shared to the terminal, and the terminal By simplifying the channel access of , it is possible to increase the uplink transmission probability in terms of channel access. That is, when the terminal wants to transmit within the COT (Channel Occupancy Time) that the base station sets and can indicate to the terminal through group common signaling, the terminal performs random back-off in a channel access method by sharing the COT from the gNB to the terminal. It can have the advantage of increasing the possibility of UL transmission through a simple Cat-2 method (a channel access method performing channel access for a single interval) or a No LBT method rather than a Cat-4 channel access method.

As another example, with reference to FIG. 19 , the UE checks whether there is an RB set of UL BWP #B after the change overlapping in the frequency domain with the RB set of UL BWP #A before the change. RB set #3 in UL BWP #B is an overlapping RB set in the frequency domain. Therefore, it can be determined that the RB set #3 in UL BWP #B is a designated RB set.

Scenario 2: One of the scenarios considered in the present invention. Referring to FIG. 20, the UE sets four RB sets (RB set #0, RB set #1, RB set #2, RB set #3) in the DL BWP. UL BWP #A includes one RB set (RB set #0 in UL BWP #A), and UL BWP #B includes three RB sets (RB set #0 in UL BWP #B, RB set #1 in UL BWP #B, RB set #2 in UL BWP #B). Here, the index of the RB set is determined according to each BWP (BWP-specific). The UE may receive the DCI format in one RB set (eg, RB set #3) of the DL BWP. Here, the DCI format may indicate to change the active UL BWP from UL BWP #A to UL BWP #B, and may schedule PUSCH to UL BWP #B. The DCI format may include Y' bits for indicating the RB set of UL BWP #A before the UL BWP change. Since UL BWP #A includes one RB set, Y' = ceil(log2(1*2/2)) = 0 bit. Accordingly, Y'=0 bit is included in the DCI format to indicate the RB set. However, since the UL BWP includes three RB sets after the change in which the PUSCH is scheduled, Y = ceil(log2(3*4/2))=3 to indicate the RB sets in which the PUSCH is scheduled among the three RB sets. bits are required. Therefore, it is a situation where Y' < Y. For reference, in this scenario, with 2^Y' = 1, the UE may be instructed with only one designated RB set combination with Y'=0 bit of the DCI format.

Possible combinations 1-3: After the change, the UE checks whether there is an overlapping RB set in the frequency domain with RB set #3 to which DCI format is transmitted among RB sets of UL BWP #B. Referring to FIG. 20, all RB sets of UL BWP #B do not overlap with RB set #3 of DL BWP through which DCI format is transmitted in the frequency domain. Therefore, since the UE cannot obtain an overlapping RB set in the frequency domain, it must determine the designated RB set by another method. As a method for this, in FIG. 20 , RB set #0 having the lowest frequency may be determined as a designated RB set. In FIG. 21 , RB set #2 having the highest frequency may be determined as a designated RB set. As another example, with reference to FIG. 22 , RB set #1 having the lowest frequency among RB sets of UL BWP overlapping DL BWP may be determined as a designated RB set.

As another example, the RB set of the UL BWP closest to RB set #3 of the DL BWP to which the DCI format is transmitted may be selected. Referring to FIG. 21 , since RB set #2 of UL BWP is closest to RB set #3 of DL BWP after change, RB set #2 of UL BWP may be determined as a designated RB set. When the RB set of the UL BWP closest in frequency to the RB set of the DL BWP transmitted with DCI format is selected, the RB set of the DL BWP assumed to be adjacent to the RB set of the DL BWP through which the DCI format is transmitted performs downlink channel access. When the channel access is performed through the Cat-2 method (channel access method for performing channel access for a single interval), the probability of the RB set(s) in the DL BWP where the channel access is successful is high, so the corresponding RB set(s) ) succeeds in channel access, the base station can increase the uplink transmission probability in terms of channel access by simplifying the channel access in the terminal through COT sharing with the terminal. That is, when the terminal wants to transmit within the COT (Channel Occupancy Time) that the base station sets and can indicate to the terminal through group common signaling, the terminal performs random back-off in a channel access method by sharing the COT from the gNB to the terminal. It can have the advantage of increasing the possibility of UL transmission through a simple Cat-2 method (a channel access method performing channel access for a single interval) or a No LBT method rather than a Cat-4 channel access method.

Scenario 3: As one of the scenarios considered in the present invention, referring to FIG. 23, the UE sets four RB sets (RB set #0, RB set #1, RB set #2, RB set #3) in the DL BWP , UL BWP #A includes two RB sets (RB set #0 in UL BWP #A, RB set #1 in UL BWP #A), and UL BWP #B includes four RB sets (RB set #0) in UL BWP #B, RB set #1 in UL BWP #B, RB set #2 in UL BWP #B, RB set #3 in UL BWP #B). Here, the index of the RB set is determined according to each BWP (BWP-specific). The UE may receive the DCI format in one RB set of the DL BWP. Here, the DCI format may indicate to change the active UL BWP from UL BWP #A to UL BWP #B, and may schedule PUSCH to UL BWP #B. The DCI format may include Y' bits for indicating the RB set of UL BWP #A before the UL BWP change. Since UL BWP #A includes two RB sets, Y' = ceil(log2(2*3/2)) = 2 bits. Accordingly, Y'=2 bits are included in the DCI format to indicate the RB set. However, since the UL BWP includes 4 RB sets after the change in which the PUSCH is scheduled, Y = ceil(log2(4*5/2))=4 to indicate the RB sets in which the PUSCH is scheduled among the 4 RB sets. bits are required. Therefore, it is a situation where Y' < Y. For reference, in this scenario, with 2^Y' = 4, the UE may indicate a combination of up to four RB sets with Y' = 2 bits of the DCI format. One RB set combination among them may include a designated RB set. In the case of a 3 RB set, ceil(log2(3*4/2)) = 3bits, which exceeds Y'=2 bits, so Y'=2bits may indicate a maximum of M=2 RB sets. Alternatively, since UL BWP #A includes two RB sets, the same number of M=2 RB sets may be indicated.

Possible combination 3-1: After the change, the UE checks whether there is an RB set that overlaps with RB set #3 to which DCI format is transmitted among RB sets of UL BWP #B in the frequency domain. Referring to FIG. 23, RB set #3 in UL BWP #B overlaps with RB set #3 through which DCI format is transmitted. Therefore, it is possible to determine the RB set #3 in UL BWP #B as a designated RB set. And the UE may be instructed by the RB set #3 in UL BWP #B with Y'=2 bits. In addition, the UE may be instructed with RB set #3 in UL BWP #B and RB set #3 in UL BWP #B and adjacent RB sets with Y'=2 bits. Therefore, in addition to RB set #3 in UL BWP #B, one RB set adjacent to RB set #3 in UL BWP #B must be selected. Here, the adjacent RB set is RB set #2 in UL BWP#B. When the RB set of the UL BWP with the DCI format overlaps with the transmitted DL BWP or the RB set with the closest frequency is selected, the RB set of the DL BWP where the DCI format is transmitted and the RB set of the DL BWP adjacent to the RB set are downlink channel access As the channel access is performed through the Cat-2 method (channel access method for performing channel access for a single interval) when performing (s) If the channel access is successful, the base station can increase the uplink transmission probability in terms of channel access by simplifying the channel access in the terminal through COT sharing with the terminal. That is, when the terminal wants to transmit within the COT (Channel Occupancy Time) that the base station sets and can indicate to the terminal through group common signaling, the terminal performs random back-off in a channel access method by sharing the COT from the gNB to the terminal. It can have the advantage of increasing the possibility of UL transmission through a simple Cat-2 method (a channel access method performing channel access for a single interval) or a No LBT method rather than a Cat-4 channel access method. In addition, in the case of uplink transmission, it may be a method of selecting adjacent RB set(s) to enable transmission of only consecutive combinations of RB set(s).

Possible combination 3-2: After the change, the UE checks whether there is an overlapping RB set in the frequency domain with RB set #1 to which DCI format is transmitted among RB sets of UL BWP #B. Referring to FIG. 24, RB set #1 in UL BWP #B overlaps with RB set #1 of DL BWP through which DCI format is transmitted. Accordingly, the RB set #1 in UL BWP #B may be determined as a designated RB set. And the UE may be instructed by the RB set #1 in UL BWP #B with Y'=2 bits. In addition, the UE may be instructed with RB sets adjacent to the RB set #1 in UL BWP #B and RB set #0 in UL BWP #B with Y'=2 bits. In the case of 4 RB sets, ceil(log2(4*5/2)) = 4bits, which exceeds Y'=2 bits, so Y'=2bits may indicate a maximum of M=2 RB sets. Therefore, in addition to RB set #1 in UL BWP #B, one RB set adjacent to RB set #1 in UL BWP #B must be selected. Here, the adjacent RB sets are RB set #0 in UL BWP#B and RB set #2 in UL BWP#B. The UE may select one of the RB sets. Here, the selection may be performed by selecting RB set #0 in UL BWP #B, which is an RB set having a lower frequency than RB set #1 in UL BWP #B, with reference to FIG. 24 . As another example, with reference to FIG. 24 , RB set #2 in UL BWP #B that is an RB set having a higher frequency than RB set #1 in UL BWP #B may be selected.

A method of interpreting Y' bits in possible combinations 3-1 to 3-2 is as follows.

In the first method, the UE may interpret Y' bits as indication information of M' RB sets of UL BWP#A. It can be determined that the scheduling information of the RB sets obtained in this way is scheduling information of the designated RB set of UL BWP#B and the adjacent RBs of the designated RB set. If Y' bits are interpreted as indication information of M' RB sets of UL BWP#A and Q RB sets are instructed from RB set #P in UL BWP#A, the designated RB set and designated RB set of UL BWP #B It can be determined that Q RB sets are instructed from the P+1-th RB set by re-indexing the RB set having the lowest index among the adjacent RBs of . For example, referring to FIG. 25, Y'=2 bits indicates RB set #0 in UL BWP#A and RB set #1 in UL BWP#A, which is RB set #1 in UL BWP #B and RB set #2 in UL BWP #B may be mapped and indicated. For example, if Y'=2 bits is 00, it may be determined that RB set #0 in UL BWP#A is indicated, which may be mapped and indicated as RB set #1 in UL BWP#B. For example, if Y'=2 bits is 01, it may be determined that RB set #1 in UL BWP#A is indicated, which may be mapped and indicated as RB set #2 in UL BWP#B.

In the second method, the UE makes Y bits by adding zeros of Y-Y' bits to the most significant bis (MSB) of Y' bits, and may interpret the Y bits as indication information of the M RB set of UL BWP #B. If Y bits are interpreted as indication information of M RB sets of UL BWP#B and Q RB sets are instructed from RB set #P in UL BWP#B, the designated RB set of UL BWP #B and the neighbor of the designated RB set The index of the RB set having the lowest index among the RBs is re-indexed to 0, so that it can be determined that Q RB sets are instructed from the P+1-th RB set. In other words, when Y bits are interpreted as indication information of M RB sets of UL BWP#B and Q RB sets are instructed from RB set #P in UL BWP#B, the designated RB set and designated RB of UL BWP #B If the index of the RB set having the lowest index among the adjacent RBs of the set is O, it can be determined that Q RB sets are instructed from RB set #(P+O) in UL BWP#B. This is the same as that obtained by shifting the RB set by O. For example, referring to FIG. 25 , Y=4 bits are made by adding 2 bits zero to Y'=2 bits. These Y bits may indicate RB set #0 in UL BWP#B and RB set #1 in UL BWP#B and RB set #2 in UL BWP#B and RB set #3 in UL BWP#B. For example, if Y=4 bits is 0000, it is determined that RB set #0 in UL BWP#B is indicated. In Fig. 25, O = 1. Therefore, it can be determined that it is mapped to RB set #(0+1) in UL BWP#B and indicated. For example, if Y=4 bits is 0001, it is determined that RB set #1 in UL BWP#B is indicated, which is mapped to RB set #(1+1) in UL BWP#B and it can be determined that it is indicated. .

As another embodiment, a combination of RB set(s) for performing downlink transmission or uplink transmission may be predefined according to regulation. That is, in the case of tying only {0,1} or {2,3} among the RB sets belonging to the active DL BWP in a method of tying two RB sets, or tying four RB sets, It can only be grouped with {0,1,2,3}. Therefore, when a bundle of predefined RB sets is set, a method of selecting the RB set(s) of the overlapping UL BWP based on the bundle of the corresponding RB sets may be considered. That is, when DCI format is transmitted from RB set #1 of DL BWP as shown in FIG. 24 and it is set to select two RB sets among RB sets of UL BWP, it is bundled with RB set #1 of DL BWP In consideration of RB set #0 of DL BWP that may be possible, select RB set(s) of UL BWP that can overlap with {0,1}, that is, DL to UL COT sharing, that is, the base station shares COT with the terminal Through , it is possible to increase the uplink transmission probability in terms of channel access by simplifying channel access in the terminal.

The above description of the present invention is for illustration, and those of ordinary skill in the art to which the present invention pertains can understand that it can be easily modified into other specific forms without changing the technical spirit or essential features of the present invention. will be. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive. For example, each component described as a single type may be implemented in a dispersed form, and likewise components described as distributed may be implemented in a combined form.

The scope of the present invention is indicated by the following claims rather than the above detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention. do.

Claims (1)

A terminal performing uplink transmission and downlink reception in a wireless communication system

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