Method and apparatus for transmitting sounding reference signal

Abstract

A method of operation of a terminal transmitting a sounding reference signal (SRS) to a base station in a wireless communication system according to an embodiment of the present invention comprises: receiving an upper layer message from the base station containing information regarding the location of an SRS resource for transmitting the SRS; receiving a trigger signal from the base station that triggers the transmission of the SRS and includes index information regarding the location of the SRS resource; performing a channel sensing operation in a wireless resource indicated by the information regarding the location of the SRS resource and the index information; and transmitting the SRS to the base station based on the channel sensing result.

Description

Technology Field

[0001] The present invention relates to a method for transmitting a sounding reference signal (SRS) of a wireless communication system, and more specifically, to a method and apparatus for transmitting a sounding reference signal capable of improving channel estimation performance at a base station. Background Technology

[0002] To handle the rapidly increasing volume of wireless data, communication systems (e.g., new radio (NR) communication systems) that use frequency bands higher than the frequency bands of LTE (long term evolution) (or LTE-A) (e.g., frequency bands below 6 GHz) (e.g., frequency bands below 6 GHz) are being considered. NR communication systems can support frequency bands above 6 GHz as well as frequency bands below 6 GHz, and can support a wider variety of communication services and scenarios compared to LTE communication systems. For example, usage scenarios for NR communication systems may include eMBB (enhanced mobile broadband), URLLC (ultra reliable low latency communication), mMTC (massive machine type communication), etc.

[0003] In a general wireless communication system, information transmitted from a terminal to a base station is referred to as uplink control information (UCI). Examples of such UCI include scheduling requests made by the terminal to the base station, downlink (DL) channel quality indicators, and acknowledgments for DL ​​data.

[0004] In communication systems using unlicensed bands, dynamic time division duplex (TDD), beam-centric communication, or low-latency communication is supported, so the number of UL symbols that a terminal allows to transmit UCI can be variable and limited.

[0005] As an example of a case where the number of UL symbols is variable, the base station may indicate the number of UL symbols to the terminal through higher layer signaling, or may indicate the number of UL symbols to the terminal through a combination of scheduling information and higher layer signaling.

[0006] As an example of a case where the number of UL symbols is limited, a base station operating in TDD may limit the number of symbols belonging to UL to a small number for the purpose of more effectively supporting DL traffic in the corresponding slot. Therefore, in a communication system using an unlicensed band, the physical channel for transmitting a sounding reference signal (SRS) may have variable time-dimensional resources and must also be able to operate with a small amount of time-dimensional resources. The problem to be solved

[0007] The present invention, aimed at solving the above-mentioned problems, has as its technical objective the provision of a sounding reference signal transmission method and apparatus capable of preventing collisions between a PUSCH (physical uplink shared channel) and an SRS when the transmission of the SRS is allowed in the same subband as the PUSCH. means of solving the problem

[0008] A method of operation of a terminal transmitting a sounding reference signal (SRS) to a base station in a wireless communication system according to an embodiment of the present invention for achieving the above objective may include: receiving an upper layer message from the base station containing information regarding the location of an SRS resource for transmitting the SRS; receiving a trigger signal from the base station that triggers the transmission of the SRS and includes index information regarding the location of the SRS resource; performing a channel sensing operation in a wireless resource indicated by the information regarding the location of the SRS resource and the index information; and transmitting the SRS to the base station based on the channel sensing result.

[0009] Here, the SRS resource includes at least one SRS transmission slot(s) determined based on the channel sensing result of the wireless resource, and the at least one SRS transmission slot(s) may include at least one SRS symbol(s).

[0010] Here, the first symbol constituting the SRS may be any OFDM (orthogonal frequency division multiplexing) symbol included in the SRS transmission slot(s).

[0011] Here, the trigger signal may indicate at least one of a candidate for the SRS transmission slot(s) among a plurality of slots, an offset between the SRS transmission slot(s), and a candidate for the first SRS symbol(s) among the symbol(s) included in each of the SRS transmission slot(s).

[0012] Here, the step of transmitting the SRS to the base station is characterized by transmitting the SRS through the symbol #n of the slot that acquired the channel sensing result transmission opportunity, and may further include the step of transmitting an initial signal prior to transmitting the wireless resource.

[0013] Here, the initial signal may be characterized by being generated based on the cyclic prefix (CP) of one of the symbols among the first symbol, the n-th symbol, and the n+1-th symbol constituting the SRS.

[0014] Here, the SRS may be characterized by being mapped in conjunction with the PUCCH (physical uplink control channel) and / or PUSCH (physical uplink shared channel) included in the wireless resource.

[0015] A method of operation of a base station receiving a sounding reference signal (SRS) in a wireless communication system according to another embodiment of the present invention for achieving the above objective may include: a step of setting the location of an SRS resource for receiving the SRS; a step of transmitting an upper layer message containing information regarding the location of the SRS resource to a terminal; a step of triggering the transmission of the SRS by the terminal and generating a trigger signal containing index information of the location of the SRS resource and transmitting it to the terminal; and a step of receiving the SRS from the terminal.

[0016] Here, the SRS resource includes at least one SRS transmission slot(s), and the at least one SRS transmission slot(s) may include at least one SRS symbol(s).

[0017] Here, the first symbol constituting the SRS may be characterized as being an orthogonal frequency division multiplexing (OFDM) symbol for each of the SRS transmission slots.

[0018] Here, the trigger signal may be characterized by indicating at least one of a candidate for the SRS transmission slot(s) among a plurality of slots, an offset between the SRS transmission slot(s), a candidate for the SRS symbol(s) among the symbols included in each of the SRS transmission slot(s), and an offset between the SRS symbol(s).

[0019] Here, the trigger signal may be characterized by further indicating the first SRS symbol among the SRS symbol(s).

[0020] Here, the SRS may be characterized by being mapped in conjunction with the PUCCH (physical uplink control channel) and / or PUSCH (physical uplink shared channel) included in the message.

[0021] A terminal for transmitting a sounding reference signal (SRS) to a base station in a wireless communication system according to another embodiment of the present invention for achieving the above objective comprises: a processor; and a memory in which at least one instruction executed through the processor is stored. The at least one instruction may be executed to receive an upper layer message from the base station that includes information regarding the location of an SRS resource for transmitting the SRS; receive a trigger signal from the base station that triggers the transmission of the SRS and includes index information regarding the location of the SRS resource; sense a channel of a wireless resource based on the information regarding the location of the SRS resource and the index information; and transmit the SRS to the base station based on the channel sensing result.

[0022] Here, the SRS resource includes at least one SRS transmission slot(s) determined based on the channel sensing result of the wireless resource, and the at least one SRS transmission slot(s) may include at least one SRS symbol(s).

[0023] Here, the first symbol constituting the SRS symbol(s) may be characterized as being an arbitrary OFDM (orthogonal frequency division multiplexing) symbol of each of the SRS transmission slot(s).

[0024] Here, the at least one command may be executed to acquire a transmission opportunity by sensing the channel of the wireless resource at an offset interval indicated by the trigger signal, starting from the first SRS symbol indicated by the trigger signal among the SRS symbol(s).

[0025] Here, the at least one command is characterized by transmitting the SRS through symbol #n, which is the first SRS symbol among the SRS symbols that acquired the channel sensing result transmission opportunity, when transmitting the SRS to the base station, and may further be executed to transmit an initial signal prior to transmitting the SRS.

[0026] Here, the initial signal may be characterized by being generated based on the cyclic prefix (CP) of one of the symbols among the first symbol, the n-th symbol, and the n+1-th symbol constituting the SRS.

[0027] Here, the SRS may be characterized by being mapped in conjunction with the PUCCH (physical uplink control channel) and / or PUSCH (physical uplink shared channel) included in the wireless resource. Effects of the invention

[0028] According to the present invention, a base station can prevent collisions between PUSCH (physical uplink shared channel) and SRS by allowing the transmission of a sounding reference signal (SRS) through an interlace structure and a comb structure of the same subband as PUSCH.

[0029] According to the present invention, the terminal can improve the channel estimation performance of the base station by transmitting a sounding reference signal over a wideband. Brief explanation of the drawing

[0030] FIG. 1 is a conceptual diagram illustrating a first embodiment of a communication system. FIG. 2 is a block diagram illustrating a first embodiment of a communication node constituting a communication system. FIG. 3 is a flowchart illustrating an embodiment of the sounding reference signal (SRS) transmission method of the present invention. FIG. 4 is a conceptual diagram illustrating a first embodiment of the SRS resource of the present invention. FIG. 5 is a conceptual diagram illustrating a second embodiment of the SRS resource of the present invention. FIG. 6 is a conceptual diagram illustrating a third embodiment of the SRS resource of the present invention. FIG. 7 is a conceptual diagram illustrating an example of the active bandwidth part (BWP) and LBT (listen before talk) subband of a wireless resource. FIG. 8 is a conceptual diagram illustrating a first embodiment of an SRS mapping method for SRS resources. FIG. 9 is a conceptual diagram illustrating a second embodiment of an SRS mapping method for SRS resources. FIG. 10 is a conceptual diagram illustrating a third embodiment of an SRS mapping method for SRS resources. FIG. 11 is a conceptual diagram illustrating an example of a frequency resource occupied by an SRS resource. FIG. 12 is a conceptual diagram illustrating an example of a time resource occupied by an SRS resource. FIG. 13 is a conceptual diagram illustrating a first embodiment of the arrangement of uplink channels and SRS resources. FIG. 14 is a conceptual diagram illustrating a second embodiment of the arrangement of uplink channels and SRS resources. FIG. 15 is a conceptual diagram illustrating a third embodiment of the arrangement of uplink channels and SRS resources. FIG. 16 is a conceptual diagram illustrating a first embodiment of an SRS resource configuration including at least one symbol. FIG. 17 is a conceptual diagram illustrating a second embodiment of an SRS resource configuration including at least one symbol. FIG. 18 is a conceptual diagram illustrating a third embodiment of an SRS resource configuration including at least one symbol. FIG. 19 is a conceptual diagram illustrating a fourth embodiment of an SRS resource configuration including at least one symbol. FIG. 20 is a conceptual diagram illustrating a first embodiment of the CWS (contention window size) and N value set in each LBT (listen before talk) subband. FIG. 21 is a conceptual diagram illustrating a second embodiment of CWS and N values ​​set for each LBT subband. FIG. 22 is a conceptual diagram illustrating a third embodiment of CWS and N values ​​set for each LBT subband. Specific details for implementing the invention

[0031] The present invention is capable of various modifications and may have various embodiments, and specific embodiments are illustrated in the drawings and described in detail. However, this is not intended to limit the invention to specific embodiments, and it should be understood that the invention includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the invention.

[0032] Terms such as "first," "second," etc., may be used to describe various components, but said components should not be limited by said terms. These terms are used solely for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be named the second component, and similarly, the second component may be named the first component. The term "and / or" includes a combination of a plurality of related described items or any of a plurality of related described items.

[0033] When it is stated that one component is "connected" or "connected" to another component, it should be understood that while it may be directly connected or connected to that other component, there may also be other components in between. On the other hand, when it is stated that one component is "directly connected" or "directly connected" to another component, it should be understood that there are no other components in between.

[0034] The terms used in this application are used merely to describe specific embodiments and are not intended to limit the invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, terms such as "comprising" or "having" are intended to specify the presence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0035] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which the present invention pertains. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this application.

[0036] Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the attached drawings. In order to facilitate an overall understanding of the present invention, the same reference numerals are used for identical components in the drawings, and redundant descriptions of identical components are omitted.

[0038] Throughout the specification, the term "terminal" may refer to a mobile station (MS), a mobile terminal (MT), an advanced mobile station (AMS), a high reliability mobile station (HR-MS), a subscriber station (SS), a portable subscriber station (PSS), an access terminal (AT), user equipment (terminal), a machine type communication device (MTC device), etc., and may include all or part of the functions of an MT, MS, AMS, HR-MS, SS, PSS, AT, UE, etc.

[0039] In addition, a base station (BS) may refer to an advanced base station (ABS), high reliability base station (HR-BS), node B, evolved node B (eNodeB), access point (AP), radio access station (RAS), base transceiver station (BTS), mobile multihop relay (MMR)-BS, relay station (RS) acting as a base station, relay node (RN) acting as a base station, advanced relay station (ARS) acting as a base station, high reliability relay station (HR-RS) acting as a base station, small base stations [femto base station (femto BS), home node B (HNB), home eNodeB (HeNB), pico base station (pico BS), macro base station (macro BS), micro base station (micro BS), etc.], and ABS, node B, eNodeB, It may include all or some of the functions of AP, RAS, BTS, MMR-BS, RS, RN, ARS, HR-RS, small base stations, etc.

[0040] A base station is configured with one or more cells, and a terminal establishes an RRC connection with at least one of the cells owned by the base station. Here, the cell that has established an RRC connection is referred to as a serving cell.

[0042] FIG. 1 is a conceptual diagram illustrating a first embodiment of a communication system.

[0043] Referring to FIG. 1, a communication system (100) may be composed of a plurality of communication nodes (110-1, 110-2, 110-3, 120-1, 120-2, 130-1, 130-2, 130-3, 130-4, 130-5, 130-6). Here, the communication system (100) may be referred to as a "communication network". Each of the plurality of communication nodes may support at least one communication protocol. For example, each of the multiple communication nodes may support a communication protocol based on CDMA (code division multiple access), WCDMA (wideband CDMA), TDMA (time division multiple access), FDMA (frequency division multiple access), OFDM (orthogonal frequency division multiplexing), OFDMA (orthogonal frequency division multiple access), SC (single carrier)-FDMA, NOMA (non-orthogonal multiple access), SDMA (space division multiple access), etc. Each of the multiple communication nodes may have the following structure.

[0045] FIG. 2 is a block diagram illustrating a first embodiment of a communication node constituting a communication system.

[0046] Referring to FIG. 2, the communication node (200) may include at least one processor (210), a memory (220), and a transceiver (230) that is connected to a network to perform communication. Additionally, the communication node (200) may further include an input interface device (240), an output interface device (250), a storage device (260), etc. Each component included in the communication node (200) may be connected by a bus (270) to communicate with one another.

[0047] The processor (210) can execute a program command stored in at least one of the memory (220) and the storage device (260). The processor (210) may mean a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor on which methods according to embodiments of the present invention are performed. Each of the memory (220) and the storage device (260) may be composed of at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory (220) may be composed of at least one of read-only memory (ROM) and random access memory (RAM).

[0049] Referring again to FIG. 1, the communication system (100) may include a plurality of base stations (110-1, 110-2, 110-3, 120-1, 120-2) and a plurality of user equipment (130-1, 130-2, 130-3, 130-4, 130-5, 130-6). Each of the first base station (110-1), the second base station (110-2), and the third base station (110-3) may form a macro cell. Each of the fourth base station (120-1) and the fifth base station (120-2) may form a small cell. A fourth base station (120-1), a third terminal (130-3), and a fourth terminal (130-4) may be located within the coverage of a first base station (110-1). A second terminal (130-2), a fourth terminal (130-4), and a fifth terminal (130-5) may be located within the coverage of a second base station (110-2). A fifth base station (120-2), a fourth terminal (130-4), a fifth terminal (130-5), and a sixth terminal (130-6) may be located within the coverage of a third base station (110-3). A first terminal (130-1) may be located within the coverage of a fourth base station (120-1). A sixth terminal (130-6) may be located within the coverage of a fifth base station (120-2).

[0050] Here, each of the multiple base stations (110-1, 110-2, 110-3, 120-1, 120-2) may be referred to as Node B, evolved Node B, base transceiver station (BTS), radio base station, radio transceiver, access point, access node, roadside unit (RSU), radio remote head (RRH), transmission point (TP), transmission and reception point (TRP), relay node, etc. Each of the multiple terminals (130-1, 130-2, 130-3, 130-4, 130-5, 130-6) may be referred to as a terminal, access terminal, mobile terminal, station, subscriber station, mobile station, portable subscriber station, node, device, etc.

[0051] Each of the multiple communication nodes (110-1, 110-2, 110-3, 120-1, 120-2, 130-1, 130-2, 130-3, 130-4, 130-5, 130-6) can support cellular communication (e.g., LTE (long term evolution), LTE-A (advanced), etc. as defined in the 3GPP (3rd generation partnership project) standard). Each of the multiple base stations (110-1, 110-2, 110-3, 120-1, 120-2) can operate in different frequency bands or in the same frequency band. Each of the multiple base stations (110-1, 110-2, 110-3, 120-1, 120-2) can be connected to each other via an ideal backhaul or a non-ideal backhaul, and can exchange information with each other via the ideal backhaul or the non-ideal backhaul. Each of the multiple base stations (110-1, 110-2, 110-3, 120-1, 120-2) can be connected to a core network (not shown) via an ideal backhaul or a non-ideal backhaul. Each of the multiple base stations (110-1, 110-2, 110-3, 120-1, 120-2) can transmit a signal received from the core network to the corresponding terminal (130-1, 130-2, 130-3, 130-4, 130-5, 130-6), and can transmit a signal received from the corresponding terminal (130-1, 130-2, 130-3, 130-4, 130-5, 130-6) to the core network.

[0052] Each of the multiple base stations (110-1, 110-2, 110-3, 120-1, 120-2) can support OFDMA-based downlink transmission and SC-FDMA-based uplink transmission. Additionally, each of the multiple base stations (110-1, 110-2, 110-3, 120-1, 120-2) can support MIMO (multiple input multiple output) transmission (e.g., SU (single user)-MIMO, MU (multi user)-MIMO, massive MIMO, etc.), CoMP (coordinated multipoint) transmission, carrier aggregation transmission, transmission in an unlicensed band, device-to-device (D2D) communication (or ProSe (proximity services)), etc. Here, each of the multiple terminals (130-1, 130-2, 130-3, 130-4, 130-5, 130-6) can perform an operation corresponding to the base station (110-1, 110-2, 110-3, 120-1, 120-2) and an operation supported by the base station (110-1, 110-2, 110-3, 120-1, 120-2).

[0053] For example, the second base station (110-2) can transmit a signal to the fourth terminal (130-4) based on the SU-MIMO method, and the fourth terminal (130-4) can receive a signal from the second base station (110-2) based on the SU-MIMO method. Alternatively, the second base station (110-2) can transmit a signal to the fourth terminal (130-4) and the fifth terminal (130-5) based on the MU-MIMO method, and each of the fourth terminal (130-4) and the fifth terminal (130-5) can receive a signal from the second base station (110-2) based on the MU-MIMO method. Each of the first base station (110-1), the second base station (110-2), and the third base station (110-3) can transmit a signal to the fourth terminal (130-4) based on the CoMP method, and the fourth terminal (130-4) can receive a signal from the first base station (110-1), the second base station (110-2), and the third base station (110-3) by the CoMP method. Each of the multiple base stations (110-1, 110-2, 110-3, 120-1, 120-2) can transmit and receive signals based on the carrier aggregation method with terminals (130-1, 130-2, 130-3, 130-4, 130-5, 130-6) within its coverage area. Each of the first base station (110-1), the second base station (110-2), and the third base station (110-3) can coordinate D2D communication between the fourth terminal (130-4) and the fifth terminal (130-5), and each of the fourth terminal (130-4) and the fifth terminal (130-5) can perform D2D communication through the coordination of each of the second base station (110-2) and the third base station (110-3).

[0055] FIG. 3 is a flowchart illustrating an embodiment of the sounding reference signal (SRS) transmission method of the present invention.

[0056] Referring to FIG. 3, the base station can derive the location of SRS resources (frequency resource location and time resource location) for the transmission of a sounding reference signal (SRS) (S310). The time resource location information can be composed of one or more uplink (UL) sub-slots, and the corresponding UL sub-slot may be located in the middle of the last symbol or UL slot. Here, the base station can derive the frequency resource location for SRS transmission using values ​​such as a transmission comb (TC) value, a bandwidth configuration variable, a bandwidth variable, a frequency hopping bandwidth variable, and frequency domain position information.

[0057] The base station can instruct the terminal on the location of the SRS resource. That is, the base station can transmit information on the location of the resource for SRS transmission to the terminal. The base station can transmit information regarding the location of at least one SRS resource for SRS transmission to the terminal using upper layer signaling. The base station can transmit some of the configuration information for setting the SRS resource to the terminal (S320). Then, the base station can transmit the remaining configuration information for setting the SRS resource that was not transmitted through the upper layer signaling to the terminal via a trigger signal (S330).

[0058] The base station can transmit an SRS resource index, which is information for configuring SRS resources, to the terminal through upper layer signaling (S320). The SRS resource index may include information regarding frequency resources, sequence information, and antenna port information, and the SRS resource index may be set for each SRS resource in the form of a pre-set list.

[0059] In a wireless communication network using an unlicensed band, the time resources for transmitting SRS may have a dynamic nature according to the LBT (listen before talk) procedure. Therefore, information regarding the time resources for transmitting SRS may be included in the trigger signal. A base station may transmit a trigger signal to a terminal through a DCI (downlink control information) field for allocating a PDSCH (physical downlink shared channel) or some of the DCI fields for allocating a PUSCH in a DL (downlink) control channel (S330). Alternatively, the base station may instruct multiple terminals through a specific DCI format pre-configured to trigger the transmission of SRS by the terminal. The base station may instruct the terminals regarding the time resources for transmitting SRS in the form of an index through upper layer signaling.

[0060] The terminal can obtain information regarding the location of an SRS resource from the upper layer signaling and DL control channel received from the base station (S340). The terminal can derive candidate resources for an SRS resource element (RE) from the index of the trigger signal. The terminal can determine a time resource to transmit an SRS by following channel sensing (e.g., LBT procedure) in a radio resource indicated by the information regarding the location of the SRS resource in the upper layer signaling and the index information of the trigger signal. The terminal can perform an LBT operation even at a time earlier than the start time of the radio resource indicated by the upper layer signaling and the trigger signal. The terminal can map an SRS to an SRS resource element based on the channel sensing result of the radio resource indicated by the information regarding the location of the SRS resource (S350). The terminal can map an SRS in the order of time resources and then map an SRS in the order of frequency resources. As another example, the terminal can map an SRS in the order of frequency resources and then map an SRS in the order of time resources.

[0061] The terminal maps the SRS to at least one SRS resource element and can transmit a subframe containing at least one resource element to the base station (S360). Accordingly, the terminal can transmit the SRS to the base station (S360). The specific configuration of the SRS resources may be as described below.

[0062] A base station performing wireless communication in an unlicensed band can set resources for transmitting SRS through upper layer signaling. The base station can transmit an index indicating SRS resources to a terminal through a DL control channel. The DL control channel may include a trigger field that triggers the terminal's SRS transmission and a time field that indicates information regarding the time of transmission of the SRS. The trigger field may indicate an index of SRS resources to be allocated to the terminal. The time field may indicate the initial resource of SRS resources to be allocated to the terminal (e.g., subframe, slot, symbol, etc.). Alternatively, the DL control channel may include only a single field without distinguishing between the trigger field and the time field. This field is represented by an index set by upper layer signaling and can indicate the time resource and frequency resource for transmitting SRS transmission as a single index.

[0063] The SRS resource may include at least one comb (e.g., 2 or 4 subcarrier intervals) arranged at regular subcarrier intervals. In contrast, the PUSCH resource may include at least one interlace arranged at regular physical resource block (PRB) intervals. Thus, the SRS resource may be time division multiplexed (TDM) with the same symbols as the PUSCH but may not be frequency division multiplexed (FDM). Therefore, in some subcarriers, the SRS may overlap with the PUSCH, but in other subcarriers, the SRS may not overlap with the PUSCH.

[0064] FIG. 4 is a conceptual diagram illustrating a first embodiment of the SRS resource of the present invention.

[0065] Referring to FIG. 4, an SRS resource according to one embodiment of the present invention may include at least one interlaced space arranged at regular intervals of physical resource blocks (PRB). A base station may transmit information regarding an SRS resource including at least one interlaced space to a terminal through upper layer signaling.

[0066] The terminal can receive upper layer signaling and DL control channels from the base station. The terminal can map an SRS to an SRS resource element belonging to a preset interlace. The SRS resource element and PUSCH can be placed in PRBs belonging to different interlaces. Therefore, the terminal can map the SRS and PUSCH to different interlaces using the FDM method.

[0067] FIG. 5 is a conceptual diagram illustrating a second embodiment of the SRS resource of the present invention.

[0068] Referring to FIG. 5, each interlaced of an SRS resource according to another embodiment of the present invention may include at least one comb arranged at a constant subcarrier interval. A base station may transmit information regarding an SRS resource including at least one interlaced and at least one comb to a terminal through upper layer signaling.

[0069] The terminal can receive upper layer signaling and DL control channels from the base station. The terminal can map SRS to each comb included in the interlace. The terminal can map SRS and PUSCH to the same interlace. However, if an SRS resource element occupies a different subcarrier than PUSCH within the same interlace, SRS can be mapped to PUSCH in an FDM manner. If DM-RS symbols and data symbols are TDMed and the DM-RS symbol is located before the data symbol, PUSCH can have a fixed interval in subcarrier units within the interlace. If PUSCH consists of two symbols, the DM-RS resource can be FDMed on the same symbol as the data; if PUSCH consists of more than two symbols (e.g., four, seven, or more), the DM-RS resource can be mapped on a different symbol from the data.

[0070] FIG. 6 is a conceptual diagram illustrating a third embodiment of the SRS resource of the present invention.

[0071] Referring to FIG. 6, SRS resource elements according to another embodiment of the present invention can be mapped to PUSCH in a code division multiplexing (CDM) manner. PUSCH may include a demodulation reference signal (DM-RS) resource of PUSCH, which is a resource for a reference signal for demodulation of PUSCH, and a PUSCH data resource, which is a resource for transmitting uplink data. The SRS resource elements and the DM-RS resource elements of PUSCH may be distributed discretely, and the SRS resource elements can be mapped to the DM-RS resource elements of PUSCH in a CDM manner.

[0072] A terminal performing wireless communication in an unlicensed band can perform an LBT procedure and transmit a signal based on the result of the LBT procedure. That is, a terminal transmitting an SRS in an unlicensed band can perform an LBT procedure prior to transmitting the SRS. Similarly, a terminal transmitting a PUSCH in an unlicensed band can perform an LBT procedure prior to transmitting the PUSCH. Therefore, the terminal can transmit an SRS using the resources allocated to the PUSCH. In particular, the terminal can transmit an SRS using the same resources allocated to the DM-RS of the PUSCH. A symbol containing resources allocated to the PUSCH DM-RS can be located first among the symbols of the PUSCH. Specifically, the terminal can map SRS resource elements and PUSCH DM-RS resource elements to symbols using the CDM method.

[0073] According to one embodiment of the present invention, the terminal can generate SRS resource elements as complex vectors having a constant length of ZC sequence (Zadoff-Chu sequence) and can map the SRS resource elements to resources having an interlaced structure and a comb structure.

[0074] When PUSCH DM-RS resource elements are generated based on a ZC sequence, the interlaced and combed structures of the resources to which SRS resource elements are mapped may be identical to the structures of the resources to which the PUSCH DM-RS resource elements are mapped. To utilize the CAZAC (constant amplitude zero auto-correlation waveform), a property of the ZC sequence, SRS resource elements may be generated from the same basis sequence as the PUSCH DM-RS resource elements. Additionally, SRS resource elements may have a different cyclic shift from the PUSCH DM-RS resource elements. Each terminal can generate SRS and PUSCH DM-RS using the same ZC sequence and different respective cyclic shift information. Each terminal can map the generated SRS and PUSCH DM-RS using the CDM method. Each terminal can transmit the generated signals to the base station. The base station can distinguish between simultaneously received signals (PUSCH DM-RS and SRS) based on the cyclic shift information.

[0075] A terminal communicating in an unlicensed band may find it difficult to accurately determine the transmission time of an SRS. If the sequence hopping and cyclic shift information of a ZC sequence depends on the time information of the SRS resource, the terminal may generate multiple SRSs based on the result of the LBT procedure, and consequently, the signal processing time and computational load of the terminal may increase. Therefore, the base station may set the sequence hopping information (e.g., group hopping, sequence shift, sequence hopping, etc.) and / or cyclic shift information of the ZC sequence independently of information regarding the time resource for transmitting the SRS (i.e., slot index or symbol index).

[0076] Furthermore, according to conventional technology, a base station may generate patterns for SRS resources using ZC sequences across the entire band of BWPs included in a common resource grid, and then refrain from mapping subsequences of the ZC sequences to resources only for PRBs corresponding to active BWPs. Terminals, on the other hand, may generate ZC sequences and map them to SRS resources only for PRBs corresponding to the required bandwidth. Therefore, if the locations of the PRBs intended for actual transmission are misaligned, multiplexing of ZC sequences (e.g., CDM-based multiplexing) may be impossible.

[0077] According to another embodiment of the present invention, the terminal can generate an SRS as a complex vector having a constant length of a PN sequence. The terminal can generate an SRS to have an interlaced structure and / or a comb structure.

[0078] When PUSCH DM-RS is generated based on a PN sequence, the interlaced structure and comb structure of the PUSCH DM-RS resource and the SRS resource may be identical. The terminal may additionally apply an orthogonal cover code (OCC) to the PN sequence to generate PUSCH DM-RS. When the terminal additionally applies an OCC to the PN sequence to generate PUSCH DM-RS, the terminal may generate an SRS based on the PN sequence. Additionally, the terminal may generate an SRS by further applying an OCC.

[0079] According to the prior art, a terminal can obtain scrambling information from a base station through upper layer signaling and can initialize a PN sequence using the scrambling information. The terminal may receive at least one scrambling information from the base station or may not receive it. For example, the terminal can generate a PUSCH DM-RS from a PN sequence according to a prior art specification (e.g., TS 38.211). Additionally, the terminal can generate a PUSCH DM-RS by further applying an OCC to the PN sequence according to a CDM group.

[0080] According to one embodiment of the present invention, the SRS resource may have a comb structure, and the number of combs k may be 2 or 4. To maintain a similar frequency response of the channel, the terminal may generate an SRS by applying OCC in PRB units in an interlacing belonging to one or more symbols.

[0081] A terminal can generate an SRS by applying an OCC with a length of h=12 / k (i.e., h=6 when k=2, h=3 when k=4) to a single PRB. When applying an OCC, the terminal can generate an SRS by applying the same PN sequence value to the same OCC. Therefore, the length of the PN sequence can be equal to the number of PRBs in the interlaced.

[0082] OCC may be one of non-orthogonal sequences such as a Hadamard sequence or a DFT (discrete Fourier transform) sequence. According to one embodiment of the present invention, if the value of h is not an exponent of 2, the terminal may apply OCC by applying a DFT sequence. The DFT sequence is h-th root of unity ( It can be composed of the indices of ). Table 1 shows the DFT sequence for h=6 ( ) can be exemplified, and Table 2 shows the DFT sequence for h=3 ( Can be an example of ).

[0083]

[0084]

[0085] The terminal is some of the h OCC indices (e.g., q, q <h)의 OCC 인덱스를 적용하여 SRS를 생성할 수 있다. q 개의 OCC 인덱스를 선택하기 위해서, 단말은 표 1 내지 표 2 중에서 This is established The columns can be selected. The column vectors selected by the terminal may have mutually orthogonal properties. Also, the column vectors selected by the terminal may have a constant complex cyclic shift interval according to the q-th root of unity. Therefore, the terminal can generate an SRS by applying an OCC index even in a frequency-selective wireless channel.

[0086] The base station may transmit scrambling information to terminals to initialize the sequence. The terminal may initialize the PN sequence using the scrambling information received from the base station. The terminal may generate an SRS by applying the initialized PN sequence. In the case where,

[0087] And a separate terminal can initialize a PN sequence using scrambling information received from a base station. A separate terminal can receive the same scrambling information from a base station. The terminal can generate a PUSCH DM-RS by applying the initialized PN sequence.

[0088] A terminal communicating in an unlicensed band may find it difficult to accurately secure the transmission timing of an SRS. Therefore, if the scrambling information of a PN sequence is set based on the time resources of an SRS (e.g., slots or symbols), the terminal may perform an LBT procedure for each of the multiple SRS symbols. Additionally, the terminal may generate an SRS based on the result of the LBT for each SRS symbol, which may increase the processing time and computational load of the terminal. Accordingly, according to one embodiment of the present invention, the scrambling information of a PN sequence may be set independently of the information of the time resources occupied by the SRS resource elements (i.e., slot index or symbol index).

[0089] And the base station can transmit OCC information to the terminals. The base station can transmit different OCC information to different terminals. Terminals can receive the same scrambling information from the base station and can receive different OCC information. Terminals can generate different signals (e.g., PUSCH DM-RS or SRS) based on the received scrambling information and OCC information. Thus, SRS can be combined with PUSCH DM-RS and CDM. Each terminal can transmit a channel containing the generated signal (e.g., PUSCH DM-RS or SRS) to the base station. The base station can receive channels containing PUSCH DM-RS and SRS from the terminals. The base station can obtain PUSCH DM-RS and / or SRS by distinguishing the received sequences.

[0090] Some of the bands among the BWPs occupied by terminals may overlap. That is, on the overlapping bands (i.e., LBT subband(s)), SRS resources may be multiplexed together. And each SRS resource may be configured in the same interlaced and combed form. The lengths of the sequences for generating SRS resources may differ, and each SRS resource may be mapped in the CDM manner.

[0091] FIG. 7 is a conceptual diagram illustrating an example of the active bandwidth part (BWP) and LBT subband of a wireless resource.

[0092] Referring to FIG. 7, SRS resources can be multiplexed over wireless resources. Terminals can occupy active BWPs that include different bandwidths. The bandwidth of an active BWP can be an integer multiple of the bandwidth of an LBT subband. A terminal can perform an LBT procedure for each LBT subband. Thus, the bandwidth of the band for transmitting SRS can be an integer multiple of the bandwidth of an LBT subband. The BWPs of the LBT subband occupied by each terminal can have different center frequencies.

[0093] According to one embodiment of the present invention, a terminal may separately generate an SRS as a unit corresponding to an LBT subband. When a terminal secures a frequency resource corresponding to a single LBT subband using an LBT procedure, the terminal may generate an SRS sequence of a length corresponding to the secured LBT subband. The terminal may map the generated SRS sequence to a common resource grid based on a reference point (e.g., reference point A) of the LBT subband.

[0094] If a terminal has secured frequency resources corresponding to two or more LBT subbands using the LBT procedure, the terminal may generate SRS sequences of length corresponding to each secured LBT subband. For each LBT subband, the terminal may map the generated SRS sequences to a common resource grid based on a reference point (e.g., reference point A).

[0095] Each LBT subband can be arranged consecutively. Consecutive LBT subbands may include consecutive PRBs. Specifically, when a terminal secures only one LBT subband by means of an LBT procedure and transmits an SRS, the LBT subband may be divided into PRBs to which the SRS is mapped and PRBs to which it is not (i.e., PRBs belonging to the boundaries of the LBT subbands). The boundaries of the LBT subband may consist of a predetermined number of PRBs. Depending on the result of performing the LBT procedure, the terminal may not map the SRS to the PRBs included in the boundaries of the LBT subbands. However, if the terminal secures two adjacent LBT subbands, the terminal may map the SRS to the PRBs included in the boundaries of the LBT subbands as well.

[0096] The base station may set a BWP for the terminal through upper layer signaling. However, if the bandwidth of the BWP is at least twice the size of the LBT subband, the base station may indicate the boundaries of the LBT subbands to the terminal in units of PRBs. For an active BWP, the terminal may use the LBT subband(s) based on the results of the LBT procedure performed prior to UL transmission. The base station may indicate the boundaries of the LBT subbands to the terminal for each BWP (band portion) through upper layer signaling. When transmitting an SRS or PUSCH, the terminal may transmit UL signals and / or channels using PRBs belonging to the boundaries of the LBT subbands.

[0097] A terminal according to another embodiment of the present invention may include PRBs that form a boundary from the LBT subband having a lower center frequency among two LBT subbands forming a boundary, and may map a sequence from a reference point (e.g., reference point A) of said LBT subband to a PRB forming a boundary. Accordingly, the terminal may map a relatively long sequence to the LBT subband having a relatively lower center frequency among the two LBT subbands, and may map a relatively short sequence to the LBT subband having a relatively higher center frequency. The difference in length of each sequence may be derived based on information regarding the number of PRBs forming a boundary.

[0098] SRS mapping method for SRS resources

[0099] Examples of SRS mapping for SRS resources may be as described below. An SRS resource may include a single interlace or some combs or transmission combs included in a single interlace. A terminal may map SRS to subcarriers sequentially. However, since an SRS resource may consist of two or more interlaces, a mapping method that can be applied regardless of the number of interlaces is required.

[0100] FIG. 8 is a conceptual diagram illustrating a first embodiment of an SRS mapping method for SRS resources.

[0101] Referring to FIG. 8, a terminal according to one embodiment of the present invention can map SRS to subcarriers sequentially. That is, even if the SRS symbol includes multiple interlaces, the terminal can map the SRS in the order of the subcarriers of the SRS resource. The terminal can map SRS to different interlaces alternately. Therefore, the SRS of the terminal may not be able to multiplex (e.g., CDM) with the signal of another terminal (e.g., PUSCH DM-RS) that uses only one interlace. If the same sequence is not mapped in a common interlace, the base station may not be able to distinguish between different signals (e.g., SRS or PUSCH DM-RS) received.

[0102] FIG. 9 is a conceptual diagram illustrating a second embodiment of an SRS mapping method for SRS resources.

[0103] Referring to FIG. 9, a plurality of interlaces included in an SRS resource according to another embodiment of the present invention may have a priority set among the interlaces. A terminal may map an SRS to an SRS resource based on priority information of the plurality of interlaces. For example, the terminal may map an SRS to subcarriers belonging to a high-priority interlace preferentially and to subcarriers belonging to a low-priority interlace secondarily.

[0104] FIG. 10 is a conceptual diagram illustrating a third embodiment of an SRS mapping method for SRS resources.

[0105] Referring to FIG. 10, different terminals according to another embodiment of the present invention may each acquire a resource (e.g., an SRS resource) containing a different number of interlaces. Each terminal may initialize a sequence for each interlace. Each terminal may map resource elements generated based on the same sequence in common interlaces to the resource. Each terminal may transmit a message containing an SRS to a base station. The base station may receive messages containing an SRS from the terminals, and the base station may distinguish different SRSs received from different terminals.

[0107] Frequency resources for SRS transmission

[0108] The terminal can obtain information regarding at least one LBT subband from the base station. The terminal can perform an LBT operation on at least one of the obtained LBT subbands. The terminal can map an SRS to an SRS resource of the LBT subband that succeeded in LBT among at least one of the LBT subbands. The terminal can transmit the SRS mapped to the SRS resource (e.g., interlaced or combed) to the base station.

[0109] If an SRS resource contains two or more symbols, the terminal may perform an LBT procedure for each symbol. If the terminal fails to transmit an SRS due to an LBT failure in some of the LBT subband(s) included in a single symbol, the terminal may perform an LBT procedure for the next symbol. If, as a result of the LBT operation, the terminal can use LBT subband(s) that it could not access in the previous symbol, the LBT subband(s) used by the terminal in that symbol may increase. Therefore, the bandwidth of the SRS symbol transmitted in the n+1th symbol may be greater than or equal to the bandwidth of the SRS symbol transmitted in the nth symbol (n=0, 1, ...). If the terminal maps an SRS in adjacent LBT subbands, the terminal may also map an SRS to a PRB belonging to a guard band.

[0111] SRS transmission method via frequency hopping

[0112] FIG. 11 is a conceptual diagram illustrating an example of a frequency resource occupied by an SRS resource.

[0113] Referring to FIG. 11, the subcarriers of the SRS resources can be configured in a comb structure that includes the entire band. The SRS is instructed to be transmitted in a narrow band, so that when the base station triggers it, the location of the band where the SRS is transmitted can change based on the index (or SRS counter) held by the terminal. When the base station triggers the terminal's SRS transmission at least once, the SRS can be transmitted at least once through all locations on the band. Therefore, the base station can know all the frequency response values ​​of the terminal's BWP. However, in unlicensed bands, the SRS resources are not defined as narrow bands but as interlaced units, and frequency regulations are satisfied by using frequency resources corresponding to a wide band, so it may be difficult to apply the conventional method as is.

[0114] According to one embodiment of the present invention, a terminal can map an SRS to a wireless resource by hopping in interlaced units. When the subcarrier spacing at which the SRS is transmitted is 15 kHz, one LBT subband may include 10 interlacs. Therefore, a base station may set one SRS resource to the terminal and trigger the SRS 10 times. The terminal may transmit the SRS through a different interlac each time, and thus the base station may estimate the channel based on all interlacs belonging to the LBT subband. Since the SRS resource may occupy frequency resources in the form of combs as well as interlacs, the base station may not be able to estimate the channel of all subcarriers belonging to the LBT subband. The terminal may map the SRS by hopping the interlacs of the SRS resource and may not map the SRS by hopping the combs. Since adjacent combs can be separated by at least one subcarrier (e.g., two or four), the combs can therefore be set to be smaller than the channel's coherence bandwidth.

[0116] Time resources for SRS transmission

[0117] FIG. 12 is a conceptual diagram illustrating an example of a time resource occupied by an SRS resource.

[0118] Referring to FIG. 12, the SRS resource can be mapped to the last symbol(s) of a subframe or slot. However, since terminals in the unlicensed band transmit the SRS based on the result of the LBT operation, after the terminals compete on the UL resource, only one terminal may transmit the UL signal and / or channel through the UL resource, or multiple terminals may transmit the UL signal and / or channel through the FDM or CDM method. Therefore, the SRS can be FDM or CDM with the PUSCH. Also, the first symbol belonging to the SRS resource may be the same symbol as the first symbol belonging to the PUSCH. Additionally, the first symbol of the PUSCH may contain the DM-RS resource, and thus the SRS can be mapped to the start symbol of the PUSCH. The first symbol of the PUSCH may be any symbol not limited to the first or last symbol of the slot, and thus the first symbol of the SRS resource may be any symbol of the slot.

[0119] To transmit an SRS, the terminal may perform an LBT procedure. When transmitting an SRS using a time resource (channel occupancy time (COT)) allocated from the base station, the terminal may perform a short LBT (e.g., Category 2 LBT). In contrast, when transmitting an SRS using a time resource secured by the terminal itself (e.g., COT), the terminal may perform a long LBT (e.g., Category 3 or 4 LBT). Since the SRS symbol index(s) of an SRS resource located within a subframe or slot may be fixed, the base station may transmit a DL control channel that triggers only the first subframe or slot initiating the LBT procedure in the form of an index to transmit information regarding the SRS resource.

[0120] A PUSCH can occupy time resources in units shorter than a subframe or slot (e.g., a mini-slot or sub-slot). Therefore, the terminal must acquire additional symbol indices of SRS resources to transmit SRS through them.

[0121] The base station may transmit a DCI containing a trigger signal to the terminal. The trigger signal may include index information indicating the location of an SRS resource. The index information of the trigger signal may indicate a time resource for SRS transmission. Specifically, the index information of the SRS resource may include all resources for transmitting the SRS (e.g., time, frequency, sequence, precoding information, or preprocessing information). The trigger signal may convey sufficient information by indicating only the index of the SRS resource. Therefore, the capacity of the trigger signal can be reduced. On the other hand, since all resources of the SRS resource are set as the index, the capacity of upper-layer signaling (e.g., RRC messages) may increase.

[0122] The terminal can receive a trigger signal from the base station. The terminal can obtain information regarding time resources for transmitting an SRS from the received trigger signal. The terminal can perform an LBT procedure from the time indicated by the trigger signal. The terminal can transmit an SRS through the first time resource among the resources that succeeded in the LBT.

[0123] If an SRS resource contains two or more symbols, the first symbol of the SRS resource may be any symbol belonging to a slot. Therefore, depending on the result of the LBT procedure, the last symbol of the SRS resource may belong to a different slot than the first symbol of the SRS resource. When a single SRS resource is transmitted through multiple slots, the scheduling and interference environments experienced by the serving base stations of each slot may differ. Therefore, it may be desirable for a single SRS resource to belong to only one slot. Accordingly, when transmitting an SRS resource, the terminal transmits starting from the first symbol belonging to the SRS resource, but may omit the transmission procedure without transmitting symbols that cross the boundary of the corresponding slot.

[0124] The terminal can receive a trigger signal through the n-th slot. The terminal can then sequentially perform an LBT procedure starting from the n+u slot after the slot offset (u). The terminal can transmit an SRS by performing the LBT procedure on the earliest symbol among the candidate symbols in the n+u slot (i.e., symbol t1 in slot n+u). If the LBT procedure fails for all candidate symbols in the n+u slot (e.g., all symbols in the slot), the terminal may not transmit an SRS through that slot. In one embodiment, the terminal may not transmit an SRS further. In another embodiment, the terminal may perform the same operation in a subsequent slot (i.e., slot n+u+1).

[0125] According to one embodiment, the upper layer signaling may indicate a slot offset for transmitting the SRS. According to another embodiment, the upper layer signaling may indicate a slot offset for transmitting the SRS and a symbol index or the first symbol (t1) transmitted by the SRS resource. If the upper layer signaling does not separately indicate the first symbol transmitted by the SRS resource, the terminal may perform an LBT procedure starting from the first symbol of slot n+u (i.e., t1=0) to transmit the SRS.

[0126] In the case of an NR system, the base station can transmit a trigger signal to an unspecified number of terminals in DCI format 2_3. Each of the unspecified number of terminals can check information regarding the slot for transmitting SRS according to the upper layer signaling. Since the location indicated by is known, each terminal can obtain an SRS trigger index based on the DCI format 2_3 information. The terminal can derive an SRS transmission slot based on slot offset (u) information and can perform an LBT procedure starting from the first symbol of the derived slot. According to one embodiment of the present invention, the index of the trigger signal may indicate slot offsets and / or candidates for symbols (t1, t2, t3, ..., tT). The index of the trigger signal may indicate information regarding encoded slot offsets and / or candidates for symbols. For example, the slot offset and the number of slots may be indicated to the terminal using a single index, and the candidates for symbols may be set to the terminal via the upper layer signaling.

[0127] While only one set of candidates may be known to the terminal, if multiple sets of candidates are known to the terminal, the terminal can obtain candidate set information indicated by the index of the trigger signal. According to another embodiment, candidates for symbols may be indicated by upper-level signaling, and slot offsets may be indicated by the trigger signal.

[0128] The terminal can receive a trigger signal through the n-th slot. The terminal can then sequentially perform an LBT procedure on the candidate symbols included in the n+u slot after the slot offset (u). The terminal can transmit an SRS through the earliest symbol among the candidate symbols that passed the LBT procedure (i.e., symbol t1 in slot n+u). If none of the candidate symbols in the n+u slot (i.e., symbols t1, t2, ..., tT in slot n+u) passed the LBT procedure, the terminal may not transmit an SRS through that slot.

[0129] According to another embodiment of the present invention, the index of the trigger signal may indicate a slot offset (u) and / or a symbol offset (t). The index of the trigger signal may indicate encoded slot offset information and symbol offset information. For example, the slot offset and the number of slots may be indicated to the terminal using a single index. According to one embodiment, candidates for symbols may be indicated through the index of the trigger signal and a separate indicator. According to another embodiment, the index of the trigger signal may indicate the slot offset, the number of slots, and the symbol offset. Alternatively, the slot offset and the number of slots may be indicated by the trigger signal, and the symbol offset may be set by upper-level signaling. According to yet another embodiment, the symbol offset may be indicated by upper-level signaling, and the slot offset may be indicated by the trigger signal.

[0130] The terminal can sequentially perform an LBT procedure to determine whether it can transmit an SRS at symbol t in a slot (n+u) that occurs after a slot offset (u) from the slot (n) that received the trigger signal, and transmit an SRS. According to one embodiment of the present invention, if the LBT procedure is not passed at the corresponding candidate symbol belonging to the corresponding slot, the terminal may not transmit an SRS. The terminal may attempt the LBT procedure in the next slot (n+u+1). According to one embodiment of the present invention, the terminal may attempt the LBT procedure at candidate symbols (i.e., symbols t1, t2, .., tT) belonging to the corresponding slot (i.e., slot n+u), and may not transmit an SRS in subsequent slots.

[0131] According to another embodiment of the present invention, the index of the trigger signal may indicate candidates for slots (n1, n2, ..., nw) and / or a symbol offset (t).

[0132] Candidate slot sets and symbol offset information can be simultaneously encoded and included in the trigger signal in the form of an index. For example, if only one set of slot candidates is configured for the terminal at the upper layer, there is no need to include it in the trigger signal to instruct the terminal; however, if two or more candidate sets are configured for the terminal, the trigger signal may include them in the form of an index so that the terminal can recognize a single candidate set. The symbol offset may be instructed to the terminal as an index along with the slot candidates, allowing the terminal to derive both the slot candidates and the symbol offset from a single index. Alternatively, the slot candidate set information may be indicated by the trigger signal, and the symbol offset information may be indicated by upper layer signaling.

[0133] The terminal can transmit an SRS by performing the LBT procedure in sequence from the slot (n) that received the trigger signal to the subsequent slot (i.e., slot n1) to the symbol with the applied symbol offset (i.e., symbol t). If the terminal fails to pass the LBT procedure for the corresponding candidate symbol in the slot, it may not transmit the SRS. If the terminal fails the LBT procedure for all symbols included in the slot, it may perform the LBT procedure starting from the first symbol included in the next slot (i.e., slot n2) (i.e., symbol t). If the terminal fails the LBT procedure in slot nw as well as at the last position of the symbol candidates (i.e., symbol t), it does not transmit the SRS.

[0134] According to another embodiment of the present invention, the index of the trigger signal may indicate candidates for slots (n1, n2, ..., nw) and / or candidates for symbols (t1, t2, t3, ..., tT).

[0135] Here, some of this information may be encoded simultaneously and included in the trigger signal in the form of an index. For example, a candidate set of slots may be indicated to the terminal using a single index, and a candidate set of symbols may be set to the terminal via upper-layer signaling. Alternatively, a single index may indicate to the terminal not only the candidate set of slots but also the candidate set of symbols.

[0136] The terminal can transmit an SRS by performing the LBT procedure sequentially from the slot (n) that received the trigger signal to the slot that occurs thereafter (i.e., slot n1), starting from the symbol candidate (i.e., symbol t1). If the LBT procedure is not passed for the corresponding candidate symbol in the slot, the terminal can determine whether it can transmit an SRS by performing the LBT procedure for the next symbol (i.e., symbol t2). If the terminal fails the LBT procedure for all symbols included in the slot, it can perform the LBT procedure starting from the first candidate symbol (i.e., symbol t1) included in the next slot (i.e., slot n2). If the terminal fails the LBT procedure for the last position of the symbol candidates (i.e., symbol tT) in slot nw, it may not transmit an SRS.

[0138] Configuration where SRS and PUSCH / PUCCH are TDM

[0139] The base station can trigger the terminal's SRS transmission by transmitting a DCI containing a trigger signal. The DCI may be a DL-DCI for allocating a PDSCH, or a UL-DCI for allocating a PUSCH. The SRS may be transmitted through a different resource (e.g., symbols) than the PUSCH or PUCCH (physical uplink control channel).

[0140] FIG. 13 is a conceptual diagram illustrating a first embodiment of the arrangement of uplink channels and SRS resources.

[0141] Referring to FIG. 13, a base station can trigger an SRS transmission by a terminal through a DCI (i.e., DL-DCI or UL-DCI). When the transmission of an SRS is triggered by the DCI, the DCI may include information regarding SRS resources and resources of UL channels (i.e., PUSCH and / or PUCCH). The SRS resources and resources of UL channels may be arranged in temporal contiguous order.

[0142] The DCI may include information regarding the start symbol of an SRS resource. The DCI may also include information regarding the start symbol of a UL channel resource. If the SRS resource and the UL channel resource are not placed adjacent to each other, the base station may indicate the start symbols of each resource (e.g., SRS resource, PUSCH and / or PUCCH) through different fields of the DCI. If the SRS resource is placed adjacent to the UL channel resource, the base station may indicate only the start symbol of the SRS resource or the UL channel resource to the terminal through the DCI. The base station may transmit the DCI containing information regarding the SRS resource to the terminal. The DCI allocating the UL channel may further indicate the category of the LBT procedure as well as the start time resource of the UL channel. The terminal may derive the start time resource of the UL channel and the category of the LBT procedure based on an index set by the upper layer signaling. For example, in the case of an NR system, a specific field of the DCI may indicate the value of the index, and the index indicated by the DCI may indicate the type of LBT procedure and the extension length of the CP (cyclic prefix). The extension length of the CP may be one of four values. For example, the index indicated by the DCI may indicate one of the following values: 0 (i.e., no extension of the CP to be applied to the UL channel), the length of C1 symbols minus 25 µs, the length of C2 symbols minus (16 µs + TA (timing advance)), and the length of C3 symbols minus (25 µs + TA). The value of C1 indicated by the index may be a value determined by the subcarrier spacing of the UL channel, and the values ​​of C2 and C3 may be values ​​given to the terminal by upper-layer signaling. The terminal may transmit the CP of the first symbol constituting the UL channel by extending it by the value indicated by the index. The terminal can receive DCI from the base station.The terminal can obtain information regarding each resource (e.g., SRS resource, PUCCH and / or PUSCH resource) from the received DCI. Based on the obtained resource information, the terminal can map resource elements to each resource. The terminal can transmit a message containing SRS and / or PUCCH / PUSCH to the base station.

[0143] Meanwhile, when two or more PUSCHs are allocated, a TDM configuration between the PUSCHs can be proposed. However, the transmission power of the SRS and the transmission power of the PUSCH may differ from each other. Therefore, the PUSCH and SRS can be mapped to each other in a TDM manner, and the PUSCHs can be deployed consecutively.

[0144] According to one embodiment of the present invention, a terminal may transmit PUSCH and / or PUCCH after transmitting SRS. A base station may transmit a DCI containing information regarding the start symbol of an SRS resource to the terminal. Upon receiving the DCI from the base station, the terminal may obtain information regarding the start symbol of an SRS resource. In the case of PUSCH, the SLIV (start and length indicator value) of the PUSCH must be generated so that the PUSCH is assigned consecutively to the last symbol of the SRS resource. In the case of PUCCH, the resource index of the PUCCH must be generated so that the PUCCH is assigned consecutively to the last symbol of the SRS resource.

[0145] Alternatively, the terminal can determine the start symbol of PUSCH and / or PUCCH from the SLIV of PUSCH (or the resource index of PUCCH). Thus, the terminal can map SRS to resources placed earlier, corresponding to the number of symbols in the SRS resource.

[0146] If an SRS resource is placed ahead of a PUSCH / PUCCH resource, the terminal may be unable to transmit the SRS due to the LBT procedure. If an SRS resource is placed ahead of a PUSCH / PUCCH resource, the probability of the terminal transmitting the SRS may be relatively low, and the probability of transmitting the PUSCH / PUCCH may be relatively high compared to the probability of transmitting the SRS. Therefore, if the priority of PUSCH / PUCCH is higher than the priority of SRS transmission, the terminal can increase the probability of transmitting the PUSCH / PUCCH by placing the SRS preferentially on the radio resource. If a single UL-DCI indicates multiple PUSCH resources, the SRS resource may be placed ahead of the multiple PUSCH resources.

[0147] FIG. 14 is a conceptual diagram illustrating a second embodiment of the arrangement of uplink channels and SRS resources.

[0148] Referring to FIG. 14, a terminal according to another embodiment of the present invention may transmit an SRS after transmitting a PUSCH and / or PUCCH. The terminal may map the SRS to a resource adjacent to the last symbol of the PUSCH resource indicated by the SLIV of the PUSCH. The base station may not indicate to the terminal the location of the start symbol of the SRS resource via UL-DCI.

[0149] A base station can receive SRS from a terminal. Based on the SRS received from the terminals, the base station can estimate the UL channel with the terminal. Then, the base station can determine the coding rate and modulation rate of the PUSCH using the estimated UL channel. Therefore, the later the terminal transmits the SRS, the less the change in the UL channel due to fading may be. According to a configuration in which SRS resources are placed after PUSCH resources, the base station can estimate the response of the UL channel with the terminal relatively more accurately. However, according to the LBT procedure, the probability of transmitting a PUSCH may be relatively lower than the probability of transmitting an SRS. Therefore, it may be desirable for the base station to secure the quality (i.e., QoS (quality of service)) of the previously placed UL-SCH through a retransmission procedure. When a single UL-DCI allocates multiple PUSCH resources, SRS resources may be placed after the multiple PUSCH resources.

[0150] Depending on the result of the LBT procedure, the terminal may not be able to transmit the UL channel (i.e., PUSCH and / or PUCCH). If the terminal fails to transmit the UL channel, the terminal may perform the LBT procedure at the next symbol following the last symbol constituting the UL channel. According to one embodiment, if the terminal fails to transmit the SRS through the time resource instructed to transmit the SRS resource as a result of performing the LBT procedure, the terminal may not transmit the SRS. According to another embodiment, even if the terminal fails to transmit the SRS through the time resource instructed to transmit the SRS resource as a result of performing the LBT procedure, the terminal may perform the LBT procedure again at the next symbol. The terminal may repeat the LBT procedure at the remaining symbols belonging to the same slot, and the terminal may transmit the SRS starting from the first symbol that passed the LBT procedure.

[0151] According to one embodiment, if the terminal fails to transmit the UL channel via the LBT procedure, the terminal may apply the extended length of the CP applied to the UL channel to the SRS resource as is. That is, the terminal may apply the extended length of the CP indicated by the DCI to the first symbol constituting the SRS resource. According to another embodiment, if the terminal fails to transmit the UL channel via the LBT procedure, the terminal may apply the extended length of the CP applied to the UL channel to each symbol belonging to the SRS resource as is. That is, among the symbols belonging to the SRS resource, the terminal may apply the extended length of the CP indicated by the DCI to the first symbol transmitted via the LBT procedure.

[0152] FIG. 15 is a conceptual diagram illustrating a third embodiment of the arrangement of uplink channels and SRS resources.

[0153] Referring to FIG. 15, according to another embodiment of the present invention, the SRS resources of PUSCH can be arranged differently from the resources of PUCCH and the wireless resources.

[0154] A base station may transmit DL-DCI and / or UL-DCI to a terminal. A terminal may receive DL-DCI and / or UL-DCI from a base station. The terminal may multiplex by distinguishing between time resources for mapping SRS resources triggered by DL-DCI and time resources for mapping SRS resources triggered by UL-DCI. According to another embodiment of the present invention, SRS resources for PUSCH may be placed after PUSCH, and SRS resources for PUCCH may be placed before PUCCH. Or conversely, SRS resources for PUSCH may be placed before PUSCH, and SRS resources for PUCCH may be placed after PUCCH.

[0155] According to the characteristics of the LBT procedure, resources deployed earlier in time may have a lower probability of being transmitted to the base station, while resources deployed later may have a relatively higher probability of being transmitted to the base station. Additionally, considering the fading of the UL channel, the response of the UL channel estimated by the base station may be accurate when deployed later in time. Therefore, communication nodes (e.g., base stations and / or terminals) can pre-set the priority between PUCCH and SRS, and pre-set the priority between PUSCH and SRS.

[0156] For example, PUCCH may have a higher priority than SRS. This is because if PUCCH is not transmitted, the base station must perform the LBT procedure to retransmit DL-DCI and PDSCH, and the terminal must also perform the LBT procedure to transmit PUCCH. However, since SRS resources can trigger only SRS resources even in DL-DCI or UL-DCI, the radio resources occupied by the base station or terminal may be smaller. Additionally, SRS serves as a reference signal for estimating the UL channel and may not be used to transmit or retransmit DL data. Furthermore, PUCCH can apply sufficiently low coding and modulation rates to ensure robust transmission even against UL channel fading. Therefore, to increase the transmission probability of PUCCH, SRS resources can be placed ahead of PUCCH resources.

[0157] For example, PUSCH may have a lower priority than SRS resources. To retransmit PUSCH, the base station can dynamically determine the coding rate and modulation rate based on the fading of the UL channel. Therefore, for accurate UL channel measurement by the base station, SRS resources may be placed after PUSCH.

[0158] Time resources when one or more symbols constitute a single SRS resource

[0159] FIG. 16 is a conceptual diagram illustrating a first embodiment of an SRS resource configuration including at least one symbol.

[0160] Referring to FIG. 16, a single SRS resource may include at least one SRS symbol. When a terminal uses multiple antenna ports to transmit SRS, the terminal may transmit one SRS symbol through one antenna port. The terminal may acquire an SRS resource in a number of consecutive symbols equal to the number of SRS antenna ports. The terminal may acquire at least one contiguously arranged SRS resource for beam management. If the number of antennas of the terminal differs from the number of SRS antenna ports of the SRS resource, the terminal may transmit the SRS using at least one symbol through an antenna switching method. When the terminal additionally performs an LBT procedure in an unlicensed band, the time resource of an SRS resource including at least one symbol may be expressed in resource units, and specifically in symbol units.

[0161] According to one embodiment of the present invention, when a terminal passes through the LBT procedure at the first symbol of an SRS resource, it can map the SRS to the time resource that passed through the LBT procedure and transmit it to a base station.

[0162] A terminal may transmit an SRS through the first symbol of an SRS resource to transmit an SRS, whether semi-fixedly allocated, periodically, or triggered by a DCI. Even if an SRS resource consists of two or more SRS symbols, the terminal may obtain time resource information for transmitting the SRS based on the DCI received from the base station. The terminal may map the SRS to the resource indicated by the obtained time resource information.

[0163] When the base station indicates multiple time resources, the terminal may perform an LBT procedure for each time resource. As a result of performing the LBT procedure, the terminal may transmit an SRS through the first transmittable time resource among the time resources. The terminal may transmit all symbols constituting the SRS or may not transmit all symbols; thus, the so-called inter-antenna port imbalance problem, where channel tracking is possible only on some antenna ports, may not occur. Additionally, the terminal's LBT procedure for transmitting a PUSCH may be identical to the LBT procedure for transmitting the terminal's SRS.

[0164] According to one embodiment of the present invention, a terminal may attempt an LBT procedure at the next time resource to transmit an SRS. According to the LBT procedure, the terminal may transmit all symbols constituting the SRS or not transmit all symbols. If the terminal fails to succeed in the LBT procedure at the first symbol constituting the SRS resource, it may attempt the LBT procedure again at the next allowed time resource. The allowed time resource may be a specific symbol index in the next slot (e.g., the index of the first symbol of the SRS resource) or the first symbol of the next slot.

[0165] FIG. 17 is a conceptual diagram illustrating a second embodiment of an SRS resource configuration including at least one symbol.

[0166] Referring to FIG. 17, a terminal according to one embodiment of the present invention may transmit an initial signal through the first symbol of an SRS decided to be transmitted. The terminal may perform an LBT procedure by applying CWS and N in the LBT subband(s) to be used to transmit the SRS. The time at which the terminal acquires the channel may be T (e.g., tens of ns) ahead of the first symbol of the SRS. If the time at which the channel is acquired precedes the time at which the first symbol of the SRS is transmitted, the terminal may transmit the initial signal for a time of T or less than or equal to T.

[0167] If the terminal does not transmit any signal for a period T, another communication node (e.g., the terminal or a base station) may transmit a signal. Consequently, the terminal may be unable to transmit the SRS due to signal transmission by another communication node. Therefore, the terminal can prevent resource occupation by other communication nodes by transmitting an initial signal when it acquires a transmission opportunity. The initial signal for the SRS can be obtained from the first symbol constituting the SRS.

[0168] According to one embodiment of the present invention, a terminal can generate an initial signal by expanding the first symbol constituting the SRS.

[0169] If the terminal succeeds in LBT before the time when it is required to transmit SRS, the terminal may generate an initial signal by extending the CP of the first symbol constituting the SRS as needed. The length of the initial signal may be indicated by being included in the trigger signal directed to the terminal from the serving base station. The length of the initial signal may be indicated as 0, a preset time having an integer number of symbols, or a time shortened by a certain offset from the preset time (e.g., the length of time used in the LBT procedure (e.g., 25 us, 16 us) and TA (timing advance), etc.). Alternatively, the CP length may be expressed by an index set in the upper layer signaling or an index indicated in the technical specification. Due to the characteristics of the initial signal, the serving base station can ensure orthogonality between the signals of the terminals. The length of the initial signal (e.g., the length of the CP, the number of symbols, etc.) may be indicated by the interval of the BWP subcarriers or by the upper layer signaling.

[0170] The terminal can transmit the generated initial signal to the base station. The terminal may refer to the entire time interval (T) from the time of successful LBT to the time of the first symbol, or only a portion of the time interval. Even when the CP of the first symbol constituting the SRS is extended, the conventional process of generating OFDM symbols can be applied as is. This is because the more later parts of the OFDM samples can simply be placed at the front. When the base station receives the SRS symbol and applies the DFT interval, the terminal can utilize the remaining OFDM samples excluding the extended OFDM samples and the OFDM samples of the CP. The terminal can transmit the respective channels after generating the initial signal when transmitting not only the SRS but also the PUSCH and PUCCH.

[0172] FIG. 18 is a conceptual diagram illustrating a third embodiment of an SRS resource configuration including at least one symbol.

[0173] Referring to FIG. 18, among the symbols constituting the SRS resources according to one embodiment of the present invention, an SRS can be transmitted starting from the time resource for the first SRS transmission that has passed the LBT procedure. Unlike PUSCH, the SRS can function on a symbol-by-symbol basis. In the process of decoding PUSCH, the base station can decode PUSCH using all symbols. The base station can measure the quality of different wireless links using each symbol constituting the SRS. A terminal can be allocated at least one PUSCH mapped in type B mode and can transmit starting from the PUSCH mapped in type B mode that has passed the LBT procedure for the first time. The terminal can transmit starting from the symbol that has passed the LBT procedure for the first time among the PUSCH mapped in type A mode. At this time, the terminal can puncture the symbols (or REs) that could not be transmitted for the encoded TB (or codeword) and transmit the part of the codeword mapped to the first symbol that succeeded in the LBT procedure.

[0174] To transmit the various symbols constituting the SRS, the terminal may perform the LBT procedure for each time resource allocated for SRS transmission. Prior to transmitting the SRS, it can be assumed that subsequent SRS transmissions will continue to utilize LBT subbands. Therefore, the terminal may not perform the LBT procedure again for LBT subbands that it has already secured using the LBT procedure. However, for LBT subbands that have not been secured, the terminal may perform the LBT procedure immediately before transmitting the SRS symbols.

[0175] According to one embodiment of the present invention, if a terminal fails to perform an LBT operation in all slots constituting an SRS resource, the terminal may perform the LBT procedure again in the next slot. The index of the symbol constituting the SRS resource in the next slot may be maintained as the same as that of the previous slot.

[0176] According to another embodiment of the present invention, if a terminal fails an LBT operation in all slots constituting an SRS resource, the terminal may no longer transmit the SRS. The base station may transmit a new trigger signal to the terminal. The terminal that failed the LBT operation may retransmit the SRS after receiving the new trigger signal from the base station.

[0178] FIG. 19 is a conceptual diagram illustrating a fourth embodiment of an SRS resource configuration including at least one symbol.

[0179] Referring to FIG. 19, a terminal according to one embodiment of the present invention may transmit an initial signal for the first symbol determined to transmit an SRS. The terminal may successfully complete an LBT procedure approximately tens of nanoseconds prior to transmitting the SRS symbol. The terminal may perform UL transmission starting from a symbol located after the symbol that succeeded in the LBT procedure. To prevent resource occupation by other communication nodes (e.g., base stations or terminals), the terminal may transmit an initial signal. The terminal may generate an initial signal based on the generated SRS symbol.

[0180] If the LBT procedure is successful prior to the first symbol of the SRS resource, the terminal may utilize the extended CP of the first symbol constituting the SRS as the initial signal. The length of the initial signal may be included in the trigger signal directed to the terminal from the serving base station. The length of the initial signal may be indicated as 0, a preset time having an integer number of units of the symbol, or a time shortened by a certain offset from the preset time (e.g., the length of time used in the LBT procedure (e.g., 25 us, 16 us) and TA (timing advance), etc.). Alternatively, the CP length may be expressed as an index set in the upper layer signaling or an index indicated in the technical specification. Due to the characteristics of the initial signal, the serving base station can ensure orthogonality between the signals of the terminals. The length of the initial signal (e.g., the length of the CP, the number of symbols, etc.) may be indicated by the interval of the BWP subcarriers or by upper-layer signaling. If the LBT procedure is successful immediately before transmitting the second or subsequent symbols, rather than the first symbol of the SRS, the following method may be applied. For the sake of convenience of explanation, the time at which the LBT procedure is successful can be assumed to be between symbol n and symbol n+1 (n=0,1,2,...). Before transmitting the first symbol of the SRS, the terminal can secure a time of several tens of nanoseconds through the LBT procedure. And after the second or subsequent symbols of the SRS, the terminal can secure a time of several tens of microseconds through the LBT procedure.

[0181] As a result of performing the LBT procedure, the terminal may not be able to transmit the SRS symbol n to the base station. Therefore, according to one embodiment of the present invention, the terminal may utilize the extended CP of the n+1th symbol constituting the SRS transmitted after the time resource in which the LBT procedure was successful as an initial signal.

[0182] According to another embodiment of the present invention, a terminal can construct an initial signal using the n-th symbol constituting the SRS corresponding to the time resource in which the LBT procedure was successful. Since the time resource in which the LBT procedure was successful is the interval in which the symbol n constituting the SRS must be transmitted, the terminal can use the OFDM symbol derived from the symbol n constituting the SRS. From the time resource in which the LBT procedure was successful until the start time of the symbol n+1 (and the corresponding CP) constituting the SRS, the terminal can use the OFDM symbol possessed by the SRS symbol n. The base station may not detect the exact start time of the terminal's UL transmission. The base station can determine whether the terminal's UL signal and / or channel is being transmitted by detecting energy. The base station can perform a DFT on the received UL signal and / or channel to distinguish between OFDM symbols determined to be mapped to the signal in units of OFDM symbols and OFDM symbols that are not mapped to the signal. The base station can estimate the UL channel using only the OFDM symbols that are mapped to the signal (i.e., by utilizing only a portion of the SRS symbol n).

[0183] The terminal can ensure phase continuity while transmitting part of SRS symbol n and all of SRS symbol n+1. The PAPR of the power amplifier may momentarily increase when the terminal begins transmitting SRS symbol n. Then, when the terminal transmits SRS symbol n+1, the PAPR of the power amplifier stabilizes and may be the same as the PAPR at the time when all SRS symbols are transmitted.

[0184] Channel access method of a terminal transmitting a UL resource element (e.g., SRS resource element, PUSCH) through a bandwidth portion (BWP) spanning two or more LBT subbandwidths.

[0185] For channel access also known as C4LBT (category 4 LBT), the terminal can manage the contention window size (CWS) according to a set rule. The terminal can select an arbitrary number smaller than the CWS and set the selected number as the counter N. If an active BWP occupies two or more LBT subbands, the terminal can manage the CWS and counter values ​​maintained for UL transmission for each LBT subband (i.e., CWS1, N1, CWS2, N2, etc.). A single CWS is defined according to the channel access priority class (CAPC) of the LBT subband, which is expressed as "per p" for convenience of explanation. Alternatively, the terminal can manage the CWS and counter values ​​as a single value independent of the LBT subband.

[0187] FIG. 20 is a conceptual diagram illustrating a first embodiment of CWS and N values ​​set for each LBT subband.

[0188] Referring to FIG. 20, an active BWP according to one embodiment of the present invention may have a unique counter value N for each LBT subband (A1). When each LBT subband has a unique N, the terminal can manage CWS for each LBT subband. Therefore, both CWS and N can be set differently for each LBT subband. The terminal can select one N to perform UL transmission. Specifically, the terminal can select one N among a plurality of Ns (e.g., the counter value N of a reference LBT subband). The terminal can select the largest N among the N values ​​of the LBT subbands.

[0189] Meanwhile, a method can be considered in which a single CWS is managed in the active BWP so that multiple LBT subbands share a single CWS. The CWS can be set to a single value, and therefore N can also be defined as a single value.

[0191] FIG. 21 is a conceptual diagram illustrating a second embodiment of CWS and N values ​​set for each LBT subband.

[0192] Referring to FIG. 21, a terminal according to one embodiment of the present invention can manage a counter value N regardless of the bandwidth of the active BWP (A2). The CWS for setting the counter value N can be expressed as a function of the CWS of the LBT subbands belonging to the active BWP. For the CAPC of the traffic to be transmitted, the terminal can select one LBT subband among the LBT subbands. For example, the terminal can select an LBT subband having the largest CWS or the smallest CWS among the CWS of the LBT subbands. The counter value N can be set based on the CWS of the selected LBT subband.

[0193] A terminal can set a counter value N to perform UL transmission and may have a CWS for each LBT subband. If the terminal fails to transmit the UL channel in some LBT subbands, or if the terminal transmits PUSCH but the base station fails to decode it, the terminal may update the CWS of the LBT subband.

[0194] When an active BWP includes multiple LBT subbands, the terminal may manage a separate CWS to apply to the LBT subband allocated for UL transmission or the LBT subband used for UL transmission when updating the CWS.

[0195] According to one embodiment of the present invention, a terminal can manage CWS for each LBT subband (with one N value). When the terminal receives a NACK for PUSCH from a base station (for example, when an NDI is toggled at the same HPID or when a NACK is received as a DFI (Downlink Feedback Indicator)), the terminal can update CWS in all LBT subbands belonging to an active BWP by reflecting the NACK.

[0196] If the terminal fails to transmit UL in some LBT subbands, the terminal may be considered not to have transmitted UL through some LBT subbands. Therefore, the terminal may update only the CWS of the LBT subbands where UL transmission was successful and / or failed.

[0197] If a base station directs a UL grant to use only some of the LBT subbands among the active BWPs, the terminal may use the CWS of some of the LBT subbands according to the directed UL grant. The terminal may select one LBT subband among the LBT subbands. For example, the terminal may select an LBT subband having the largest CWS or the smallest CWS among the CWS of the LBT subbands. The terminal may set a counter N based on the CWS of the selected LBT subband.

[0199] FIG. 22 is a conceptual diagram illustrating a third embodiment of CWS and N values ​​set for each LBT subband.

[0200] Referring to FIG. 22, a terminal according to one embodiment of the present invention can manage one CWS in an active BWP. Thus, at least one LBT subband can share one CWS (with one N value).

[0201] The terminal may transmit only one UL signal and / or channel in the BWP. Therefore, the terminal may select a reference CWS or define only one CWS (per p) without managing a CWS for each of the LBT subbands in at least one LBT subband.

[0202] If a terminal fails to transmit UL in some LBT subbands, the terminal may update the CWS by considering the number of failed LBT subbands. The terminal may manage one CWS. Therefore, if the terminal updates the CWS due to failed LBT subbands, the terminal may also apply the updated CWS to LBT subbands where LBT was successful (for all p).

[0203] The terminal is allocated PUSCH in N LBT subbands, and M( <N)개의 LBT 부분대역을 통해 PUSCH를 전송함에 있어, 단말은 PUSCH를 재전송할 수 있다. 기지국이 동일한 HPID로 NDI의 토글 없이 UL 그랜트를 단말에게 지시할 수 있다. 단말은 CWS의 크기를 증가시킬 수 있다. 종래의 방법에 의하면, N=1인 경우에 한정되므로, CWS 의 크기는 1 증가하거나 최대값(예를 들어, CWSp,max)을 유지할 수 있다.

[0204] According to one embodiment of the present invention, the size of CWS can be given as a function of M. According to one embodiment, as CWS is updated, the size of CWS can increase by M. Alternatively, as CWS is updated, the size of CWS can have a maximum value (per p). That is, when CWS is updated, the size of CWS can be updated to the smaller value between CWSp+M and CWSp,max.

[0205] According to another embodiment, as the terminal updates the CWS, the size of the CWS may increase by M / N. Alternatively, as the CWS is updated, the size of the CWS may have a maximum value (per p). That is, when the CWS is updated, the size of the CWS may be updated to the smaller value between CWSp + M / N and CWSp,max.

[0206] The methods according to the present invention may be implemented in the form of program instructions that can be executed through various computer means and recorded on a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, etc., either alone or in combination. The program instructions recorded on the computer-readable medium may be those specifically designed and configured for the present invention, or they may be those known and available to those skilled in the art of computer software.

[0207] Examples of computer-readable media include hardware devices specifically configured to store and execute program instructions, such as ROM, RAM, and flash memory. Examples of program instructions include machine code, such as that produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter, etc. The aforementioned hardware devices may be configured to operate as at least one software module to perform the operation of the present invention, and vice versa.

[0208] Although the invention has been described with reference to the above embodiments, those skilled in the art will understand that various modifications and changes can be made to the invention without departing from the spirit and scope of the invention as described in the following claims.

Claims

Claim 1 A method of a terminal, comprising: receiving first configuration information for a sounding reference signal (SRS) from a base station; receiving downlink control information (DCI) from the base station, which includes scheduling information for a physical uplink shared channel (PUSCH) and transmission request information for the SRS; and transmitting the PUSCH and the SRS to the base station in the same slot based on the DCI, wherein the SRS is transmitted after the transmission of the PUSCH. Claim 2 A method of a terminal according to claim 1, wherein the PUSCH is associated with priority index 0, the PUSCH and the SRS are transmitted in different symbols, and the SRS is transmitted after the transmission of the PUSCH and the DM-RS (demodulation reference signal) corresponding to the PUSCH. Claim 3 A method of a terminal according to claim 1, wherein the PUSCH has a lower priority than the SRS. Claim 4 A method of a terminal according to claim 1, further comprising the step of receiving second setting information from the base station, the information including information on a first length of a cyclic prefix (CP) extension and information on a second length of the CP extension, wherein the DCI further comprises information indicating the length of a prefix signal prior to the SRS, and the step of transmitting the PUSCH and the SRS comprises transmitting the prefix signal and the SRS having the said length, and wherein the length of the prefix signal is determined based on one of a plurality of lengths of the CP extension including the first length and the second length. Claim 5 A method of a terminal according to claim 4, wherein the first length and the second length each indicate the number of symbols for CP expansion. Claim 6 A method of a terminal according to claim 4, wherein the first length and the second length each vary according to subcarrier spacing. Claim 7 A method of a terminal according to claim 4, wherein the length of the prefix signal is a value obtained by subtracting a predefined value from one of the plurality of lengths. Claim 8 A method of a terminal according to claim 7, wherein the predefined value is 0, 25 μs, 16 μs+TA (timing advance), or 25 μs+TA, and the predefined value indicates a duration used for LBT (listen before talk) operation. Claim 9 A method of a terminal according to claim 4, wherein the prefix signal comprises the CP of the first symbol of the SRS. Claim 10 A method of a terminal according to claim 1, wherein the first setting information includes resource mapping information of the SRS, and the resource mapping information includes information about the location of the first symbol of the SRS and information about the number of symbols of the SRS. Claim 11 A method of a base station comprising: transmitting first configuration information for a sounding reference signal (SRS) to a terminal; transmitting downlink control information (DCI) to the terminal, the DCI including scheduling information for a physical uplink shared channel (PUSCH) and transmission request information for the SRS; and receiving the PUSCH and the SRS from the terminal in the same slot based on the DCI, wherein the SRS is received after the reception of the PUSCH. Claim 12 A method of a base station according to claim 11, wherein the PUSCH is associated with priority index 0, the PUSCH and the SRS are received at different symbols, and the SRS is received after the reception of the PUSCH and the DM-RS (demodulation reference signal) corresponding to the PUSCH. Claim 13 A method of a base station according to claim 11, wherein the PUSCH has a lower priority than the SRS. Claim 14 A method of a base station according to claim 11, further comprising the step of transmitting to the terminal second setting information including information on a first length of a cyclic prefix (CP) extension and information on a second length of the CP extension, wherein the DCI further comprises information indicating the length of a prefix signal prior to the SRS, and the step of receiving the PUSCH and the SRS comprises receiving the prefix signal and the SRS having the said length, and wherein the length of the prefix signal is determined based on one of a plurality of lengths of the CP extension including the first length and the second length. Claim 15 A method of a base station according to claim 14, wherein the first length and the second length each indicate the number of symbols for CP expansion. Claim 16 A method of a base station according to claim 14, wherein the first length and the second length each vary according to subcarrier spacing. Claim 17 A method of a base station according to claim 14, wherein the length of the prefix signal is a value obtained by subtracting a predefined value from one of the plurality of lengths. Claim 18 A method of a base station according to claim 17, wherein the predefined value is 0, 25 μs, 16 μs+TA (timing advance), or 25 μs+TA, and the predefined value indicates the duration used for LBT (listen before talk) operation. Claim 19 A method of a base station according to claim 14, wherein the prefix signal comprises the CP of the first symbol of the SRS. Claim 20 A method of a base station according to claim 11, wherein the first setting information includes resource mapping information of the SRS, and the resource mapping information includes information about the location of the first symbol of the SRS and information about the number of symbols of the SRS.

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