A terminal to perform sidelink communication in an unlicensed band in a wireless communication system and an apparatus therefor

Abstract

A method and apparatus for transmitting a signal in an unlicensed band by a first terminal in a wireless communication system supporting sidelink communication according to various embodiments are disclosed. The method includes the step of arbitrarily selecting a value of a back-off counter within a contention window associated with an unlicensed band and the step of transmitting a first signal in the unlicensed band based on the back-off counter, wherein the first signal is a sidelink signal with HARQ (Hybrid Automatic Repeat and request) feedback enabled, and wherein the size of the contention window is updated based on a feedback signal including an ACK (Acknowledgement) among feedback signals for the first signal received from a plurality of terminals.

Description

Technology Field

[0001] This relates to a method for a terminal to transmit a sidelink signal in an unlicensed band in a wireless communication system and a device for the same. Background Technology

[0002] A wireless communication system is a multiple access system that supports communication with multiple users by sharing available system resources (e.g., bandwidth, transmission power, etc.). Examples of multiple access systems include CDMA (code division multiple access), FDMA (frequency division multiple access), TDMA (time division multiple access), OFDMA (orthogonal frequency division multiple access), SC-FDMA (single carrier frequency division multiple access), and MC-FDMA (multi carrier frequency division multiple access) systems.

[0003] Sidelink (SL) refers to a communication method in which User Equipment (UE) establishes a direct link to directly exchange voice or data between terminals without passing through a Base Station (BS). SL is being considered as a solution to address the burden on base stations caused by rapidly increasing data traffic.

[0004] V2X (vehicle-to-everything) refers to a communication technology that exchanges information with other vehicles, pedestrians, and infrastructure-equipped objects through wired or wireless communication. V2X can be classified into four types: V2V (vehicle-to-vehicle), V2I (vehicle-to-infrastructure), V2N (vehicle-to-network), and V2P (vehicle-to-pedestrian). V2X communication can be provided through PC5 interfaces and / or Uu interfaces.

[0005] Meanwhile, as more communication devices require larger communication capacities, the need for improved mobile broadband communication compared to existing Radio Access Technology (RAT) is emerging. Accordingly, communication systems considering services or terminals sensitive to reliability and latency are being discussed; next-generation radio access technology that incorporates improved mobile broadband communication, Massive Machine Type Communication (MTC), and Ultra-Reliable and Low Latency Communication (URLC) can be referred to as new radio access technology (new RAT) or new radio (NR). Vehicle-to-everything (V2X) communication can also be supported in NR.

[0006] Figure 1 is a diagram illustrating a comparison between V2X communication based on RAT prior to NR and V2X communication based on NR.

[0007] Regarding V2X communication, prior to NR, RATs mainly discussed methods for providing safety services based on V2X messages such as BSM (Basic Safety Message), CAM (Cooperative Awareness Message), and DENM (Decentralized Environmental Notification Message). V2X messages can include location information, dynamic information, attribute information, etc. For example, a terminal can transmit a CAM of the periodic message type and / or a DENM of the event-triggered message type to another terminal.

[0008] For example, the CAM may include basic vehicle information such as dynamic state information of the vehicle, such as direction and speed, static data of the vehicle, such as dimensions, external lighting conditions, and route history. For example, a terminal may broadcast the CAM, and the latency of the CAM may be less than 100ms. For example, in the event of an unexpected situation such as a vehicle breakdown or accident, the terminal may generate a DENM and transmit it to other terminals. For example, all vehicles within the transmission range of the terminal may receive the CAM and / or DENM. In this case, the DENM may have a higher priority than the CAM.

[0009] Since then, regarding V2X communication, various V2X scenarios have been presented in NR. For example, various V2X scenarios may include vehicle platooning, advanced driving, extended sensors, remote driving, etc.

[0010] For example, based on vehicle platooning, vehicles can dynamically form groups and move together. For example, to perform platoon operations based on vehicle platooning, vehicles belonging to said group can receive periodic data from the lead vehicle. For example, vehicles belonging to said group can use said periodic data to reduce or increase the distance between vehicles.

[0011] For example, based on enhanced driving, vehicles can be semi-automated or fully automated. For example, each vehicle can adjust trajectories or maneuvers based on data acquired from local sensors of nearby vehicles and / or nearby logical entities. Additionally, for example, each vehicle can mutually share driving intentions with nearby vehicles.

[0012] For example, based on extended sensors, raw data or processed data or live video data acquired through local sensors can be exchanged between vehicles, logical entities, pedestrian terminals and / or V2X application servers. Thus, for example, a vehicle can perceive an environment that is enhanced compared to the environment it can detect using its own sensors.

[0013] For example, based on remote driving, a remote driver or V2X application can operate or control a remote vehicle for a person unable to drive or for a remote vehicle located in a dangerous environment. For example, in cases where the route is predictable, such as in public transportation, cloud computing-based driving can be used for the operation or control of the remote vehicle. Additionally, access to a cloud-based back-end service platform, for example, can be considered for remote driving.

[0014] Meanwhile, methods to specify service requirements for various V2X scenarios, such as vehicle platooning, enhanced driving, extended sensors, and remote driving, are being discussed in NR-based V2X communication. The problem to be solved

[0015] The problem to be solved is to provide a method and apparatus capable of ensuring smooth sidelink communication in an unlicensed band by updating a contention window that considers the HARQ feedback characteristics for sidelink signals in relation to a contention window operating in an unlicensed band.

[0016] The technical problems are not limited to those mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art to which the present invention belongs from the description below. means of solving the problem

[0017] A method for a first terminal to transmit a signal in an unlicensed band in a wireless communication system that supports sidelink communication according to one aspect includes the step of arbitrarily selecting a value of a back-off counter within a contention window associated with the unlicensed band and the step of transmitting a first signal in the unlicensed band based on the back-off counter, wherein the first signal is a sidelink signal with HARQ (Hybrid Automatic Repeat and request) feedback enabled, the size of the contention window may be updated based on a feedback signal including an ACK (Acknowledgement) among feedback signals for the first signal received from a plurality of terminals.

[0018] Alternatively, the size of the contention window is characterized by being initialized to an initial value based on a feedback signal including an ACK, even if a feedback signal including a NACK (Negative ACK) is included among the feedback signals.

[0019] Alternatively, the size of the contention window is characterized by being maintained or initialized to an initial value based on the number of feedback signals including the ACK among the feedback signals being greater than or equal to a preset number.

[0020] Alternatively, the size of the contention window is updated to increase by a preset allowable value based on the fact that the number of feedback signals including the ACK is less than a preset number.

[0021] Alternatively, the size of the contention window is characterized by being maintained or initialized to an initial value based on the ratio of the feedback signal including the ACK among the feedback signals being greater than or equal to a preset threshold ratio.

[0022] Alternatively, based on the fact that the first signal is a sidelink signal in which only the HARQ feedback of NACK (Negative ACK) is activated, the size of the contention window is maintained or initialized to an initial value based on the fact that feedback signals for the first signal from the plurality of terminals are not received.

[0023] Alternatively, based on the fact that the first signal is a sidelink signal in which only the HARQ feedback of the NACK (Negative ACK) is activated, the size of the contention window is maintained or initialized to an initial value based on the fact that the feedback signal including the NACK is received at a value below a specific threshold strength.

[0024] Alternatively, based on the fact that the first signal is the sidelink signal with the HARQ feedback disabled, the size of the contention window is updated based on the number of retransmissions of the same transport block (TB) associated with the first signal.

[0025] Alternatively, based on the fact that the first signal is a sidelink signal requesting a CSI (Channel State Information) report, the size of the contention window is maintained or initialized to an initial value when the CSI report corresponding to the first signal is received.

[0026] Alternatively, the method further includes the step of selecting a transmission resource for transmitting the first signal, wherein the transmission resource is re-selected based on the fact that the transmission resource precedes the expiration time of the backoff counter.

[0027] The first signal is characterized by being a physical sidelink shared channel (PSSCH) scheduled by a physical sidelink control channel (PSCCH) that includes information indicating activation of the sidelink HARQ feedback.

[0028] In a wireless communication system that supports sidelink communication according to another aspect, a first terminal transmitting a signal in an unlicensed band includes a Radio Frequency (RF) transceiver and a processor connected to the RF transceiver, and the processor arbitrarily selects a value of a back-off counter within a contention window related to the unlicensed band and controls the RF transceiver to transmit a first signal in the unlicensed band based on the back-off counter, and based on the fact that the first signal is a sidelink signal with Hybrid Automatic Repeat and request (HARQ) feedback enabled, the size of the contention window may be updated based on a feedback signal including an Acknowledgement (ACK) among the feedback signals for the first signal received from a plurality of terminals.

[0029] Alternatively, the size of the contention window is characterized by being maintained or initialized to an initial value based on the number of feedback signals including the ACK among the feedback signals being greater than or equal to a preset number.

[0030] A chipset that transmits a signal in an unlicensed band in a wireless communication system that supports sidelink communication according to another aspect comprises at least one processor and at least one memory that is operablely connected to said at least one processor and, when executed, causes said at least one processor to perform an operation, said operation includes arbitrarily selecting a value of a back-off counter within a contention window associated with the unlicensed band and controlling an RF transceiver to transmit a first signal in said unlicensed band based on said back-off counter, and based on said first signal being a sidelink signal with HARQ (Hybrid Automatic Repeat and request) feedback enabled, the size of said contention window may be updated based on a feedback signal including an ACK (Acknowledgement) among feedback signals for said first signal received from a plurality of terminals.

[0031] A computer-readable storage medium comprising at least one computer program that performs the operation of transmitting a signal in an unlicensed band in a wireless communication system that supports side-link communication according to another aspect comprises said at least one computer program and a computer-readable storage medium in which said at least one computer program is stored, and said operation includes arbitrarily selecting a value of a back-off counter within a contention window related to an unlicensed band and controlling the RF transceiver to transmit a first signal in the unlicensed band based on said back-off counter, and based on said first signal being a side-link signal with HARQ (Hybrid Automatic Repeat and request) feedback enabled, the size of said contention window may be updated based on a feedback signal including an ACK (Acknowledgement) among feedback signals for said first signal received from a plurality of terminals. Effects of the invention

[0032] Various embodiments can ensure smooth sidelink communication in the unlicensed band by updating the contention window in relation to the contention window operating in the unlicensed band, taking into account the HARQ feedback characteristics for the sidelink signal.

[0033] In addition, even if multiple feedback signals corresponding to a single signal exist in sidelink communication, a clear standard can be provided to effectively update the contention window in the unlicensed band.

[0034] In addition, the contention window in the unlicensed band can be updated even when only the NACK feedback signal is received in sidelink communication.

[0035] In addition, the contention window in the unlicensed band can be updated by utilizing the reception of information in response to CSI report requests and / or requests for coordination information between UEs in sidelink communication.

[0036] The effects obtainable from the present invention are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art from the description below. Brief explanation of the drawing

[0037] The drawings attached to this specification are intended to provide an understanding of the present invention, to illustrate various embodiments of the invention, and to explain the principles of the invention together with the description in the specification. Figure 1 is a diagram illustrating a comparison between V2X communication based on RAT prior to NR and V2X communication based on NR. Figure 2 shows the structure of an LTE system. Figure 3 shows the structure of the NR system. Figure 4 shows the structure of a wireless frame of NR. Figure 5 shows the slot structure of an NR frame. Figure 6 shows the radio protocol architecture for SL communication. Figure 7 shows a terminal performing V2X or SL communication. Figure 8 shows a resource unit for V2X or SL communication. Figure 9 illustrates a procedure in which a terminal performs V2X or SL communication depending on the transmission mode. FIG. 10 illustrates a wireless communication system that supports an unlicensed band. Figure 11 illustrates a method of occupying resources within an unlicensed band. Figures 12 and 13 are Channel Access Procedure (CAP) flowcharts for signal transmission through the unlicensed band. FIG. 14 illustrates RB interlacing. FIG. 15 is a diagram illustrating a method for updating the size of a contention window based on a sidelink feedback signal in an unlicensed band. FIGS. 16 and 17 are flowcharts illustrating a method for a first terminal to transmit a sidelink signal based on a contention window in an unlicensed band. FIG. 18 illustrates a communication system to which the present invention is applied. FIG. 19 illustrates a wireless device that can be applied to the present invention. FIG. 20 illustrates another example of a wireless device to which the present invention applies. The wireless device may be implemented in various forms depending on the use-example / service. FIG. 21 illustrates a vehicle or autonomous vehicle to which the present invention is applied. Specific details for implementing the invention

[0038] A wireless communication system is a multiple access system that supports communication with multiple users by sharing available system resources (e.g., bandwidth, transmission power, etc.). Examples of multiple access systems include CDMA (code division multiple access), FDMA (frequency division multiple access), TDMA (time division multiple access), OFDMA (orthogonal frequency division multiple access), SC-FDMA (single carrier frequency division multiple access), and MC-FDMA (multi carrier frequency division multiple access) systems.

[0039] Sidelink refers to a communication method in which User Equipment (UE) establishes a direct link to directly exchange voice or data between terminals without passing through a Base Station (BS). Sidelink is being considered as a solution to address the burden on base stations caused by rapidly increasing data traffic.

[0040] V2X (vehicle-to-everything) refers to a communication technology that exchanges information with other vehicles, pedestrians, and infrastructure-equipped objects through wired or wireless communication. V2X can be classified into four types: V2V (vehicle-to-vehicle), V2I (vehicle-to-infrastructure), V2N (vehicle-to-network), and V2P (vehicle-to-pedestrian). V2X communication can be provided through PC5 interfaces and / or Uu interfaces.

[0041] Meanwhile, as more communication devices require larger communication capacities, the need for improved mobile broadband communication compared to existing Radio Access Technology (RAT) is emerging. Accordingly, communication systems considering services or terminals sensitive to reliability and latency are being discussed; next-generation radio access technology that incorporates improved mobile broadband communication, Massive MTC, and URLLC (Ultra-Reliable and Low Latency Communication) can be referred to as new radio access technology (new RAT) or new radio (NR). Vehicle-to-everything (V2X) communication can also be supported in NR.

[0042] The following technologies can be used in various wireless communication systems such as CDMA (code division multiple access), FDMA (frequency division multiple access), TDMA (time division multiple access), OFDMA (orthogonal frequency division multiple access), and SC-FDMA (single carrier frequency division multiple access). CDMA can be implemented using wireless technologies such as UTRA (universal terrestrial radio access) or CDMA2000. TDMA can be implemented using wireless technologies such as GSM (global system for mobile communications), GPRS (general packet radio service), and EDGE (enhanced data rates for GSM evolution). OFDMA can be implemented using wireless technologies such as IEEE (institute of electrical and electronics engineers) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, and E-UTRA (evolved UTRA). IEEE 802.16m is an evolution of IEEE 802.16e and provides backward compatibility with systems based on IEEE 802.16e. UTRA is part of UMTS (universal mobile telecommunications system). 3GPP (3rd generation partnership project) LTE (long term evolution) is part of E-UMTS (evolved UMTS) which uses E-UTRA (evolved-UMTS terrestrial radio access), employing OFDMA in the downlink and SC-FDMA in the uplink.LTE-A (advanced) is an evolution of 3GPP LTE.

[0043] 5G NR is a successor technology to LTE-A and is a new clean-slate type mobile communication system with characteristics such as high performance, low latency, and high availability. 5G NR can utilize all available spectrum resources, ranging from low frequency bands below 1 GHz to mid-frequency bands from 1 GHz to 10 GHz, and high frequency (millimeter wave) bands above 24 GHz.

[0044] For clarity of explanation, the description focuses on LTE-A or 5G NR, but the technical concept of the embodiment(s) is not limited thereto.

[0045] Figure 2 shows the structure of an applicable LTE system. This can be called an E-UTRAN (Evolved-UMTS Terrestrial Radio Access Network), or an LTE (Long Term Evolution) / LTE-A system.

[0046] Referring to FIG. 2, the E-UTRAN includes a base station (20; Base Station, BS) that provides a control plane and a user plane to a terminal (10). The terminal (10) may be fixed or mobile and may be referred to by other terms such as MS (Mobile Station), UT (User Terminal), SS (Subscriber Station), MT (Mobile Terminal), or Wireless Device. The base station (20) refers to a fixed station that communicates with the terminal (10) and may be referred to by other terms such as eNB (evolved-NodeB), BTS (Base Transceiver System), or Access Point.

[0047] Base stations (20) can be connected to each other through an X2 interface. The base station (20) is connected to the EPC (Evolved Packet Core, 30) through the S1 interface, more specifically to the MME (Mobility Management Entity) through the S1-MME and to the S-GW (Serving Gateway) through the S1-U.

[0048] The EPC (30) is configured with an MME, an S-GW, and a P-GW (Packet Data Network-Gateway). The MME holds information regarding the terminal's connection information or capabilities, and this information is primarily used for managing the terminal's mobility. The S-GW is a gateway with an E-UTRAN as its endpoint, and the P-GW is a gateway with a PDN as its endpoint.

[0049] The layers of the Radio Interface Protocol between a terminal and a network can be classified into L1 (Layer 1), L2 (Layer 2), and L3 (Layer 3) based on the lower three layers of the Open System Interconnection (OSI) model, which is widely known in communication systems. Among these, the Physical Layer, belonging to Layer 1, provides Information Transfer Services using a physical channel, while the Radio Resource Control (RRC) layer, located at Layer 3, performs the role of controlling radio resources between the terminal and the network. To this end, the RRC layer exchanges RRC messages between the terminal and the base station.

[0050] Figure 3 shows the structure of the NR system.

[0051] Referring to FIG. 3, the NG-RAN may include gNBs and / or eNBs that provide user plane and control plane protocol termination to terminals. FIG. 7 illustrates a case where only gNBs are included. The gNBs and eNBs are connected to each other via Xn interfaces. The gNBs and eNBs are connected to the 5G Core Network (5GC) via NG interfaces. More specifically, they are connected to the access and mobility management function (AMF) via NG-C interfaces and to the user plane function (UPF) via NG-U interfaces.

[0052] Figure 4 shows the structure of a wireless frame of NR.

[0053] Referring to FIG. 4, radio frames can be used for uplink and downlink transmission in NR. The radio frame has a length of 10 ms and can be defined as two 5 ms half-frames (HF). A half-frame may contain five 1 ms subframes (SF). A subframe may be divided into one or more slots, and the number of slots within a subframe may be determined by the subcarrier spacing (SCS). Each slot may contain 12 or 14 OFDM(A) symbols according to the cyclic prefix (CP).

[0054] When normal CP is used, each slot may contain 14 symbols. When extended CP is used, each slot may contain 12 symbols. Here, the symbols may include OFDM symbols (or CP-OFDM symbols) and SC-FDMA (Single Carrier - FDMA) symbols (or DFT-s-OFDM (Discrete Fourier Transform-spread-OFDM) symbols).

[0055] Table 1 below shows the number of symbols per slot ((N) according to the SCS setting (u) when normal CP is used. slot symb ), number of slots per frame((N frame,u slot ) and the number of slots per subframe((N subframe,u slot ) exemplifies.

[0056] SCS (15*2 u ) N slot symb N frame,u slot N subframe,u slot 15KHz (u=0) 14 10 1 30KHz (u=1) 14 20 2 60KHz (u=2) 14 40 4 120KHz (u=3) 14 80 8 240KHz (u=4) 14 160 16

[0057] Table 2 shows the number of symbols per slot, the number of slots per frame, and the number of slots per subframe according to the SCS when an extended CP is used.

[0058] SCS (15*2 u ) N slot symb N frame,u slot N subframe,u slot 60KHz (u=2) 12 40 4

[0059] In an NR system, OFDM(A) numerology (numerology) (e.g., SCS, CP length, etc.) can be configured differently among multiple cells merged into a single terminal. Accordingly, the (absolute time) interval of a time resource (e.g., subframe, slot, or TTI) (collectively referred to as TU (Time Unit) for convenience) configured with the same number of symbols can be configured differently among the merged cells.

[0060] In NR, multiple new technologies or SCSs may be supported to support various 5G services. For example, if the SCS is 15 kHz, a wide area in traditional cellular bands may be supported, and if the SCS is 30 kHz / 60 kHz, dense-urban, lower latency, and wider carrier bandwidth may be supported. If the SCS is 60 kHz or higher, a bandwidth greater than 24.25 GHz may be supported to overcome phase noise.

[0061] The NR frequency band can be defined by two types of frequency ranges. The two types of frequency ranges may be FR1 and FR2. The numerical values ​​of the frequency ranges may change, for example, as shown in Table 3 below. Among the frequency ranges used in an NR system, FR1 may mean "sub 6GHz range" and FR2 may mean "above 6GHz range" and may be referred to as millimeter wave (mmW).

[0062] Frequency Range designation Corresponding frequency range Subcarrier Spacing (SCS) FR1 450MHz - 6000MHz 15, 30, 60kHz FR2 24250MHz - 52600MHz 60, 120, 240kHz

[0063] As described above, the numerical value of the frequency range of the NR system may change. For example, FR1 may include a band of 410 MHz to 7125 MHz as shown in Table 4 below. That is, FR1 may include a frequency band of 6 GHz (or 5850, 5900, 5925 MHz, etc.) or higher. For example, the frequency band of 6 GHz (or 5850, 5900, 5925 MHz, etc.) or higher included within FR1 may include an unlicensed band. The unlicensed band may be used for various purposes, for example, for communication for vehicles (e.g., autonomous driving).

[0064] Frequency Range designation Corresponding frequency range Subcarrier Spacing (SCS) FR1 410MHz - 7125MHz 15, 30, 60kHz FR2 24250MHz - 52600MHz 60, 120, 240kHz

[0065] Figure 5 shows the slot structure of an NR frame.

[0066] Referring to FIG. 5, a slot contains multiple symbols in the time domain. For example, in the case of a normal CP, one slot may contain 14 symbols, but in the case of an extended CP, one slot may contain 12 symbols. Alternatively, in the case of a normal CP, one slot may contain 7 symbols, but in the case of an extended CP, one slot may contain 6 symbols.

[0067] A carrier includes multiple subcarriers in the frequency domain. A Resource Block (RB) can be defined as multiple (e.g., 12) consecutive subcarriers in the frequency domain. A Bandwidth Part (BWP) can be defined as multiple consecutive (P)RBs ((Physical) Resource Blocks) in the frequency domain and can correspond to a single numerology (numerology) (e.g., SCS, CP length, etc.). A carrier can include up to N (e.g., 5) BWPs. Data communication can be performed through the active BWPs. Each element can be referred to as a Resource Element (RE) in a resource grid and can be mapped to a single complex symbol.

[0068] Meanwhile, a wireless interface between terminals or a wireless interface between a terminal and a network may be composed of L1, L2, and L3 layers. In various embodiments of the present disclosure, L1 layer may refer to the physical layer. Additionally, for example, L2 layer may refer to at least one of the MAC layer, RLC layer, PDCP layer, and SDAP layer. Additionally, for example, L3 layer may refer to the RRC layer.

[0069] V2X or SL (sidelink) communication will be explained below.

[0070] Figure 6 illustrates a radio protocol architecture for SL communication. Specifically, Figure 6 (a) shows the user plane protocol stack of NR, and Figure 6 (b) shows the control plane protocol stack of NR.

[0071] The Sidelink Synchronization Signal (SLSS) and synchronization information are described below.

[0072] SLSS is an SL-specific sequence that may include PSSS (Primary Sidelink Synchronization Signal) and SSSS (Secondary Sidelink Synchronization Signal). The PSSS may be referred to as S-PSS (Sidelink Primary Synchronization Signal), and the SSSS may be referred to as S-SSS (Sidelink Secondary Synchronization Signal). For example, length-127 M-sequences may be used for S-PSS, and length-127 Gold sequences may be used for S-SSS. For example, a terminal may use S-PSS to detect a primary signal and obtain synchronization. For example, a terminal may use S-PSS and S-SSS to obtain detailed synchronization and detect a synchronization signal ID.

[0073] PSBCH (Physical Sidelink Broadcast Channel) may be a (broadcast) channel through which basic (system) information that a terminal must know first is transmitted before transmitting or receiving SL signals. For example, the basic information may include information related to SLSS, Duplex Mode (DM), TDD UL / DL (Time Division Duplex Uplink / Downlink) configuration, information related to resource pools, types of applications related to SLSS, subframe offsets, broadcast information, etc. For example, to evaluate PSBCH performance, in NR V2X, the payload size of PSBCH may be 56 bits, including a 24-bit CRC.

[0074] S-PSS, S-SSS, and PSBCH may be included in a block format that supports periodic transmission (e.g., SL SS (Synchronization Signal) / PSBCH block, hereinafter S-SSB (Sidelink-Synchronization Signal Block)). The S-SSB may have the same numeral length (i.e., SCS and CP length) as the PSCCH (Physical Sidelink Control Channel) / PSSCH (Physical Sidelink Shared Channel) within the carrier, and the transmission bandwidth may be within a (pre-)set SL BWP (Sidelink BWP). For example, the bandwidth of the S-SSB may be 11 RB (Resource Block). For example, the PSBCH may span 11 RB. Additionally, the frequency position of the S-SSB may be (pre-)set. Therefore, the terminal does not need to perform hypothesis detection at the frequency to discover the S-SSB in the carrier.

[0075] Meanwhile, in an NR SL system, multiple newmalages having different SCS and / or CP lengths may be supported. In this case, as the SCS increases, the length of the time resource for the transmitting terminal to transmit S-SSBs may decrease. Consequently, the coverage of S-SSBs may decrease. Therefore, to ensure S-SSB coverage, the transmitting terminal may transmit one or more S-SSBs to the receiving terminal within a single S-SSB transmission cycle according to the SCS. For example, the number of S-SSBs transmitted by the transmitting terminal to the receiving terminal within a single S-SSB transmission cycle may be pre-configured or configured for the transmitting terminal. For example, the S-SSB transmission cycle may be 160ms. For example, an S-SSB transmission cycle of 160ms may be supported for all SCSs.

[0076] For example, if the SCS is 15 kHz at FR1, the transmitting terminal may transmit one or two S-SSBs to the receiving terminal within one S-SSB transmission cycle. For example, if the SCS is 30 kHz at FR1, the transmitting terminal may transmit one or two S-SSBs to the receiving terminal within one S-SSB transmission cycle. For example, if the SCS is 60 kHz at FR1, the transmitting terminal may transmit one, two, or four S-SSBs to the receiving terminal within one S-SSB transmission cycle.

[0077] For example, if the SCS is 60 kHz at FR2, the transmitting terminal can transmit 1, 2, 4, 8, 16, or 32 S-SSBs to the receiving terminal within one S-SSB transmission cycle. For example, if the SCS is 120 kHz at FR2, the transmitting terminal can transmit 1, 2, 4, 8, 16, 32, or 64 S-SSBs to the receiving terminal within one S-SSB transmission cycle.

[0078] Meanwhile, when the SCS is 60 kHz, two types of CP may be supported. Additionally, depending on the CP type, the structure of the S-SSB transmitted by the transmitting terminal to the receiving terminal may differ. For example, the CP type may be Normal CP (NCP) or Extended CP (ECP). Specifically, for example, if the CP type is NCP, the number of symbols mapping PSBCH within the S-SSB transmitted by the transmitting terminal may be 9 or 8. On the other hand, for example, if the CP type is ECP, the number of symbols mapping PSBCH within the S-SSB transmitted by the transmitting terminal may be 7 or 6. For example, PSBCH may be mapped to the first symbol within the S-SSB transmitted by the transmitting terminal. For example, the receiving terminal receiving the S-SSB may perform Automatic Gain Control (AGC) operation during the first symbol interval of the S-SSB.

[0079] Figure 7 shows a terminal performing V2X or SL communication.

[0080] Referring to FIG. 7, in V2X or SL communication, the term terminal may primarily refer to a user's terminal. However, if network equipment such as a base station transmits and receives signals according to the communication method between terminals, the base station may also be considered a type of terminal. For example, terminal 1 may be a first device (100), and terminal 2 may be a second device (200).

[0081] For example, terminal 1 can select a resource unit corresponding to a specific resource within a resource pool, which represents a set of resources. Then, terminal 1 can transmit an SL signal using the said resource unit. For example, terminal 2, which is a receiving terminal, can be configured with a resource pool in which terminal 1 can transmit a signal, and can detect terminal 1's signal within said resource pool.

[0082] Here, if terminal 1 is within the connection range of the base station, the base station may inform terminal 1 of the resource pool. On the other hand, if terminal 1 is outside the connection range of the base station, another terminal may inform terminal 1 of the resource pool, or terminal 1 may use a pre-configured resource pool.

[0083] Generally, a resource pool can be composed of multiple resource units, and each terminal can select one or more resource units to use for its SL signal transmission.

[0084] Figure 8 shows a resource unit for V2X or SL communication.

[0085] Referring to FIG. 8, the total frequency resources of the resource pool can be divided into NF units, and the total time resources of the resource pool can be divided into NT units. Thus, a total of NF * NT resource units can be defined within the resource pool. FIG. 8 illustrates an example where the resource pool is repeated in a period of NT subframes.

[0086] As shown in FIG. 8, a single resource unit (e.g., Unit #0) may appear repeatedly over time. Alternatively, to obtain diversity effects in the time or frequency dimension, the index of the physical resource unit to which a single logical resource unit is mapped may change in a predetermined pattern over time. In this structure of resource units, a resource pool may refer to a set of resource units that a terminal intending to transmit an SL signal can use for transmission.

[0087] Resource pools can be subdivided into several types. For example, depending on the content of the SL signals transmitted from each resource pool, resource pools can be classified as follows.

[0088] (1) A Scheduling Assignment (SA) may be a signal containing information such as the location of the resource used by the transmitting terminal for transmission of the SL data channel, the Modulation and Coding Scheme (MCS) or Multiple Input Multiple Output (MIMO) transmission method required for demodulation of the data channel, and Timing Advance (TA). The SA may also be multiplexed and transmitted together with the SL data on the same resource unit, in which case the SA resource pool may refer to a resource pool in which the SA is multiplexed and transmitted together with the SL data. The SA may also be called the SL control channel.

[0089] (2) A Physical Sidelink Shared Channel (PSSCH) may be a resource pool used by a transmitting terminal to transmit user data. If SA is multiplexed and transmitted along with SL data on the same resource unit, only the form of the SL data channel excluding SA information can be transmitted from the resource pool for the SL data channel. In other words, REs (Resource Elements) that were used to transmit SA information on individual resource units within the SA resource pool can still be used to transmit SL data in the resource pool of the SL data channel. For example, the transmitting terminal can transmit by mapping the PSSCH to a succession of PRBs.

[0090] (3) The discovery channel may be a resource pool for a transmitting terminal to transmit information such as its ID. Through this, the transmitting terminal can enable adjacent terminals to discover it.

[0091] Even if the content of the SL signal described above is the same, different resource pools may be used depending on the transmission and reception attributes of the SL signal. For example, even if the same SL data channel or discovery message is used, it may be divided into different resource pools depending on the method of determining the transmission timing of the SL signal (e.g., whether it is transmitted at the time of reception of the synchronization reference signal or whether it is transmitted by applying a certain timing advance at the time of reception), the method of resource allocation (e.g., whether the base station assigns the transmission resource of an individual signal to the individual transmission terminal or whether the individual transmission terminal selects the individual signal transmission resource itself from within the resource pool), the signal format (e.g., the number of symbols occupied by each SL signal in one subframe, or the number of subframes used for the transmission of one SL signal), the signal strength from the base station, the transmission power strength of the SL terminal, etc.

[0092] Resource allocation in SL is explained below.

[0093] FIG. 9 illustrates a procedure in which a terminal performs V2X or SL communication according to a transmission mode. In various embodiments of the present disclosure, the transmission mode may be referred to as a mode or a resource allocation mode. Hereinafter, for convenience of explanation, the transmission mode in LTE may be referred to as an LTE transmission mode, and the transmission mode in NR may be referred to as an NR resource allocation mode.

[0094] For example, FIG. 9(a) illustrates a terminal operation associated with LTE transmission mode 1 or LTE transmission mode 3. Or, for example, FIG. 9(a) illustrates a terminal operation associated with NR resource allocation mode 1. For example, LTE transmission mode 1 can be applied to general SL communication, and LTE transmission mode 3 can be applied to V2X communication.

[0095] For example, FIG. 9(b) illustrates a terminal operation associated with LTE transmission mode 2 or LTE transmission mode 4. Or, for example, FIG. 9(b) illustrates a terminal operation associated with NR resource allocation mode 2.

[0096] Referring to FIG. 9(a), in LTE transmission mode 1, LTE transmission mode 3, or NR resource allocation mode 1, the base station can schedule SL resources to be used by the terminal for SL transmission. For example, the base station can perform resource scheduling to terminal 1 via PDCCH (more specifically, DCI (Downlink Control Information)), and terminal 1 can perform V2X or SL communication with terminal 2 according to the resource scheduling. For example, terminal 1 can transmit SCI (Sidelink Control Information) to terminal 2 via PSCCH (Physical Sidelink Control Channel) and then transmit data based on the SCI to terminal 2 via PSSCH (Physical Sidelink Shared Channel).

[0097] For example, in NR resource allocation mode 1, a terminal may receive or be allocated resources from a base station for one or more SL transmissions of a single TB (Transport Block) through a dynamic grant. For example, the base station may provide the terminal with resources for the transmission of PSCCH and / or PSSCH using a dynamic grant. For example, the transmitting terminal may report SL HARQ (Hybrid Automatic Repeat Request) feedback received from the receiving terminal to the base station. In this case, the PUCCH resources and timing for reporting the SL HARQ feedback to the base station may be determined based on the indication in the PDCCH for the base station to allocate resources for SL transmission.

[0098] For example, DCI may represent a slot offset between the DCI reception and the first SL transmission scheduled by the DCI. For example, the minimum gap between the DCI scheduling the SL transmission resource and the first scheduled SL transmission resource may not be smaller than the processing time of the terminal.

[0099] For example, in NR resource allocation mode 1, the terminal may periodically receive or be allocated a set of resources from the base station for multiple SL transmissions through a configured grant. For example, the configured grant may include configured grant type 1 or configured grant type 2. For example, the terminal may determine the TB to be transmitted in each occasion indicated by the given configured grant.

[0100] For example, a base station can allocate SL resources to terminals on the same carrier and can allocate SL resources to terminals on different carriers.

[0101] For example, an NR base station can control LTE-based SL communication. For example, an NR base station can transmit an NR DCI to a terminal to schedule LTE SL resources. In this case, for example, a new RNTI may be defined to scramble the NR DCI. For example, the terminal may include an NR SL module and an LTE SL module.

[0102] For example, after a terminal including an NR SL module and an LTE SL module receives an NR SL DCI from a gNB, the NR SL module may convert the NR SL DCI to LTE DCI Type 5A, and the NR SL module may transmit the LTE DCI Type 5A to the LTE SL module in X ms increments. For example, after the LTE SL module receives the LTE DCI Format 5A from the NR SL module, the LTE SL module may apply enable and / or disable to the first LTE subframe after Z ms. For example, X may be dynamically represented using fields of the DCI. For example, the minimum value of X may vary depending on the UE capability. For example, the terminal may report a single value depending on the UE capability. For example, X may be a positive number.

[0103] Referring to FIG. 9(b), in LTE transmission mode 2, LTE transmission mode 4, or NR resource allocation mode 2, the terminal can determine an SL transmission resource within an SL resource set by the base station / network or a preset SL resource. For example, the set SL resource or the preset SL resource may be a resource pool. For example, the terminal may autonomously select or schedule a resource for SL transmission. For example, the terminal may perform SL communication by selecting a resource itself within a set resource pool. For example, the terminal may select a resource itself within a selection window by performing a sensing and resource (re)selection procedure. For example, the sensing may be performed on a subchannel basis. Then, Terminal 1, having selected a resource itself within the resource pool, can transmit an SCI to Terminal 2 via PSCCH, and then transmit data based on the SCI to Terminal 2 via PSSCH.

[0104] For example, a terminal can assist in selecting SL resources for other terminals. For example, in NR resource allocation mode 2, a terminal can receive a configured grant for SL transmission. For example, in NR resource allocation mode 2, a terminal can schedule SL transmissions for other terminals. For example, in NR resource allocation mode 2, a terminal can reserve SL resources for blind retransmission.

[0105] For example, in NR resource allocation mode 2, the first terminal may instruct the second terminal to prioritize SL transmission using SCI. For example, the second terminal may decode said SCI, and the second terminal may perform sensing and / or resource (re)selection based on said priority. For example, said resource (re)selection procedure may include the step of the second terminal identifying candidate resources in a resource selection window and the step of the second terminal selecting a resource for (re)transmission from among the identified candidate resources. For example, the resource selection window may be a time interval in which the terminal selects a resource for SL transmission. For example, after the second terminal triggers resource (re)selection, the resource selection window may start at T1 ≥ 0, and the resource selection window may be limited by the remaining packet delay budget of the second terminal. For example, in the step where the second terminal identifies candidate resources in a resource selection window, if a specific resource is indicated by an SCI received by the second terminal from the first terminal and the L1 SL RSRP measurement for said specific resource exceeds an SL RSRP threshold, the second terminal may not determine said specific resource as a candidate resource. For example, the SL RSRP threshold may be determined based on the priority of SL transmission indicated by the SCI received by the second terminal from the first terminal and the priority of SL transmission on the resource selected by the second terminal.

[0106] For example, the L1 SL RSRP can be measured based on the SL DMRS (Demodulation Reference Signal). For example, one or more PSSCH DMRS patterns in the time domain may be set or pre-set for each resource pool. For example, PSSCH DMRS setting type 1 and / or type 2 may be identical or similar to the frequency domain pattern of the PSSCH DMRS. For example, the exact DMRS pattern may be indicated by the SCI. For example, in NR resource allocation mode 2, the transmitting terminal may select a specific DMRS pattern from among the DMRS patterns set or pre-set for the resource pool.

[0107] For example, in NR resource allocation mode 2, based on a sensing and resource (re)selection procedure, the transmitting terminal can perform the initial transmission of a Transport Block (TB) without reservation. For example, based on a sensing and resource (re)selection procedure, the transmitting terminal can reserve an SL resource for the initial transmission of a second TB using an SCI associated with a first TB.

[0108] For example, in NR resource allocation mode 2, the terminal may reserve resources for feedback-based PSSCH retransmissions through signaling associated with previous transmissions of the same TB (Transport Block). For example, the maximum number of SL resources reserved by a single transmission, including the current transmission, may be 2, 3, or 4. For example, the maximum number of SL resources may be the same regardless of whether HARQ feedback is enabled. For example, the maximum number of HARQ (re)transmissions for a single TB may be limited by a setting or preset. For example, the maximum number of HARQ (re)transmissions may be up to 32. For example, if there is no setting or preset, the maximum number of HARQ (re)transmissions may be unspecified. For example, the setting or preset may be for the transmitting terminal. For example, in NR resource allocation mode 2, HARQ feedback may be supported to release resources that are not being used by the terminal.

[0109] For example, in NR resource allocation mode 2, a terminal may use an SCI to direct one or more subchannels and / or slots used by said terminal to another terminal. For example, a terminal may use an SCI to direct one or more subchannels and / or slots reserved by said terminal for PSSCH (re)transmission to another terminal. For example, the minimum allocation unit of an SL resource may be a slot. For example, the size of a subchannel may be set for the terminal or pre-set.

[0110] The following describes SCI (Sidelink Control Information).

[0111] Control information transmitted by a base station to a terminal via PDCCH is referred to as DCI (Downlink Control Information), whereas control information transmitted by a terminal to another terminal via PSCCH may be referred to as SCI. For example, a terminal may know the start symbol of the PSCCH and / or the number of symbols in the PSCCH before decoding the PSCCH. For example, SCI may include SL scheduling information. For example, a terminal may transmit at least one SCI to another terminal to schedule the PSSCH. For example, one or more SCI formats may be defined.

[0112] For example, a transmitting terminal can transmit an SCI over a PSCCH to a receiving terminal. The receiving terminal can decode one SCI to receive the PSSCH from the transmitting terminal.

[0113] For example, a transmitting terminal may transmit two consecutive SCIs (e.g., 2-stage SCIs) to a receiving terminal over a PSCCH and / or PSSCH. The receiving terminal may decode the two consecutive SCIs (e.g., 2-stage SCIs) to receive the PSSCH from the transmitting terminal. For example, if the SCI constituent fields are divided into two groups considering a (relatively) high SCI payload size, the SCI containing the first group of SCI constituent fields may be referred to as the first SCI or 1st SCI, and the SCI containing the second group of SCI constituent fields may be referred to as the second SCI or 2nd SCI. For example, the transmitting terminal may transmit the first SCI to the receiving terminal via the PSCCH. For example, the transmitting terminal may transmit the second SCI to the receiving terminal over the PSCCH and / or PSSCH. For example, the second SCI may be transmitted to a receiving terminal via a (separate) PSCCH, or may be transmitted piggybacked with data via a PSSCH. For example, two consecutive SCIs may be applied to different transmissions (e.g., unicast, broadcast, or groupcast).

[0114] For example, a transmitting terminal may transmit some or all of the following information to a receiving terminal through an SCI. Here, for example, the transmitting terminal may transmit some or all of the following information to a receiving terminal through a first SCI and / or a second SCI.

[0115] - PSSCH and / or PSCCH-related resource allocation information, e.g., time / frequency resource locations / counts, resource reservation information (e.g., periods), and / or

[0116] - SL CSI Report Request Indicator or SL (L1) RSRP (and / or SL (L1) RSRQ and / or SL (L1) RSSI) Report Request Indicator, and / or

[0117] - SL CSI transmission indicator (on PSSCH) (or SL (L1) RSRP (and / or SL (L1) RSRQ and / or SL (L1) RSSI) information transmission indicator), and / or

[0118] - MCS information, and / or

[0119] - Transmission power information, and / or

[0120] - L1 destination ID information and / or L1 source ID information, and / or

[0121] - SL HARQ process ID information, and / or

[0122] - NDI (New Data Indicator) information, and / or

[0123] - RV (Redundancy Version) information, and / or

[0124] - QoS information (related to transmission traffic / packets), e.g., priority information, and / or

[0125] - SL CSI-RS transmission indicator or information on the number of (transmitting) SL CSI-RS antenna ports

[0126] - Location information of the transmitting terminal or location (or distance area) information of the target receiving terminal (for which SL HARQ feedback is requested), and / or

[0127] - Information on reference signals (e.g., DMRS, etc.) related to the decoding and / or channel estimation of data transmitted via PSSCH, e.g., information related to the pattern of the (time-frequency) mapping resource of the DMRS, rank information, antenna port index information;

[0128] For example, the first SCI may include information related to channel sensing. For example, the receiving terminal may decode the second SCI using PSSCH DMRS. A polar code used in PDCCH may be applied to the second SCI. For example, in a resource pool, the payload size of the first SCI may be the same for unicast, groupcast, and broadcast. After decoding the first SCI, the receiving terminal does not need to perform blind decoding of the second SCI. For example, the first SCI may include scheduling information for the second SCI.

[0129] Meanwhile, in various embodiments of the present disclosure, since the transmitting terminal can transmit at least one of SCI, the first SCI, and / or the second SCI to the receiving terminal via PSCCH, PSCCH may be replaced / substituted with at least one of SCI, the first SCI, and / or the second SCI. And / or, for example, SCI may be replaced / substituted with at least one of PSCCH, the first SCI, and / or the second SCI. And / or, for example, since the transmitting terminal can transmit the second SCI to the receiving terminal via PSSCH, PSSCH may be replaced / substituted with the second SCI.

[0130] The synchronization acquisition of the SL terminal is described below.

[0131] In TDMA (time division multiple access) and FDMA (frequency division multiple access) systems, accurate time and frequency synchronization is essential. If time and frequency synchronization is not accurate, system performance may be degraded due to Inter-Symbol Interference (ISI) and Inter-Carrier Interference (ICI). This is also true for V2X. In V2X, for time and frequency synchronization, the sidelink synchronization signal (SLSS) can be used at the physical layer, and MIB-SL-V2X (master information block-sidelink-V2X) can be used at the radio link control (RLC) layer.

[0132] The HARQ (Hybrid Automatic Repeat Request) method combines FEC and ARQ, and can improve performance by checking whether the data received by the physical layer contains undecoding errors and requesting retransmission if an error occurs.

[0133] For sidelink unicast and groupcast, HARQ feedback and HARQ combining at the physical layer may be supported. For example, when a receiving terminal operates in resource allocation mode 1 or 2, the receiving terminal may receive PSSCH from the transmitting terminal, and the receiving terminal may transmit HARQ-ACK feedback for PSSCH to the transmitting terminal using the Sidelink Feedback Control Information (SFCI) format via the Physical Sidelink Control Channel (PSFCH).

[0134] When sidelink HARQ feedback is enabled for unicast, in the case of non-Code Block Group (non-CBG) operation, if the receiving terminal successfully decodes the transmission block, the receiving terminal may generate a HARQ-ACK. The receiving terminal may then transmit the HARQ-ACK to the transmitting terminal. If the receiving terminal fails to successfully decode the transmission block after decoding the associated PSCCH targeting the receiving terminal, the receiving terminal may generate a HARQ-NACK. The receiving terminal may then transmit the HARQ-NACK to the transmitting terminal.

[0135] When sidelink HARQ feedback is enabled for group cast, the terminal can decide whether to send HARQ feedback based on TX / RX distance and / or RSRP. For non-CBG operation, two options may be supported.

[0136] (1) Option 1: After the receiving terminal has decoded the associated PSCCH, if the receiving terminal fails to decode the transmission block, the receiving terminal may transmit a HARQ-NACK over the PSFCH. Otherwise, the receiving terminal may not transmit a signal over the PSFCH.

[0137] (2) Option 2: If the receiving terminal successfully decodes the transmission block, the receiving terminal may transmit a HARQ-ACK on the PSFCH. After the receiving terminal decodes the associated PSCCH targeting the receiving terminal, if the receiving terminal fails to successfully decode the transmission block, the receiving terminal may transmit a HARQ-NACK on the PSFCH.

[0138] In the case of Mode 1 resource allocation, the time between the HARQ feedback transmission on the PSFCH and the PSSCH can be (pre-)set. In the case of unicast and group cast, if retransmission is required on the sidelink, this can be indicated to the base station by a terminal within the coverage using the PUCCH. The transmitting terminal may also transmit an indication to the serving base station of said transmitting terminal in the form of a Scheduling Request (SR) or Buffer Status Report (BSR), rather than in the form of a HARQ ACK / NACK. Additionally, even if the base station does not receive said indication, the base station may schedule the sidelink retransmission resource to the terminal.

[0139] In the case of mode 2 resource allocation, the time between the HARQ feedback transmission on the PSFCH and the PSSCH can be (pre-)set.

[0140] Sidelink congestion control is described below.

[0141] When a terminal determines sidelink transmission resources independently, it also determines the size and frequency of the resources it uses. Of course, due to constraints from the network and other sources, the use of resource size or frequency exceeding a certain level may be limited. However, in a situation where many terminals are concentrated in a specific area at a given time, if all terminals use relatively large amounts of resources, overall performance may be significantly degraded due to mutual interference.

[0142] Therefore, the terminal needs to monitor channel conditions. If it is determined that an excessive amount of resources is being consumed, it is desirable for the terminal to take action to reduce its own resource usage. In this specification, this may be defined as Congestion Control (CR). For example, the terminal may determine whether the energy measured in a unit time / frequency resource exceeds a certain level, and may adjust the amount and frequency of its transmission resources according to the ratio of unit time / frequency resources in which energy exceeding a certain level is observed. In this specification, the ratio of time / frequency resources in which energy exceeding a certain level is observed may be defined as the Channel Busy Ratio (CBR). The terminal may measure the CBR for a channel / frequency. Additionally, the terminal may transmit the measured CBR to a network / base station.

[0143] Wireless communication system supporting unlicensed bands

[0144] FIG. 10 shows an example of a wireless communication system supporting an unlicensed band applicable to the present invention.

[0145] In the following description, a cell operating in the Licensed Band (L-band) is defined as an L-cell, and the carrier of an L-cell is defined as (DL / UL) LCC (Licensed Component Carrier). Additionally, a cell operating in the Unlicensed Band (U-band) is defined as a U-cell, and the carrier of a U-cell is defined as (DL / UL) UCC. The cell's carrier / carrier-frequency may refer to the cell's operating frequency (e.g., center frequency). Cells / carriers (e.g., CC) are collectively referred to as cells.

[0146] As shown in FIG. 10(a), when a terminal and a base station transmit and receive signals through carrier-coupled LCCs and UCCs, the LCC may be set as PCC (Primary CC) and the UCC may be set as SCC (Secondary CC). As shown in FIG. 10(b), the terminal and the base station may transmit and receive signals through a single UCC or multiple carrier-coupled UCCs. That is, the terminal and the base station may transmit and receive signals through only UCC(s) without LCC. For standalone operation, PRACH, PUCCH, PUSCH, SRS transmission, etc. may be supported in the UCELL.

[0147] Hereinafter, the signal transmission and reception operation in the unlicensed band described above in the present invention can be performed based on all the deployment scenarios described above (unless otherwise noted).

[0148] Unless otherwise noted, the following definitions may apply to terms used in this specification.

[0149] - Channel: Consists of a series of RBs in which the channel connection process is performed in the shared spectrum, and may refer to a carrier or a part of a carrier.

[0150] - Channel Access Procedure (CAP): Represents a procedure for evaluating channel availability based on sensing to determine whether other communication node(s) are using the channel before signal transmission. The basic unit for sensing is a sensing slot with a duration of Tsl = 9us. If a base station or terminal senses the channel during the sensing slot duration, and the power detected for at least 4us within the sensing slot duration is less than the energy detection threshold XThresh, the sensing slot duration Tsl is considered to be idle. Otherwise, the sensing slot duration Tsl = 9us is considered to be busy. CAP may be referred to as LBT (Listen-Before-Talk).

[0151] - Channel occupancy: Refers to the corresponding transmission(s) on the channel(s) by the base station / terminal after the channel access procedure is performed.

[0152] - Channel Occupancy Time (COT): Refers to the total time during which any base station / terminal(s) sharing channel occupancy with said base station / terminal can perform transmission(s) on the channel after the base station / terminal has performed the channel access procedure. When determining the COT, if the transmission gap is 25 µs or less, the gap period is also counted in the COT. The COT may be shared for transmission between the base station and the corresponding terminal(s).

[0153] - DL transmission burst: Defined as a set of transmissions from a base station without gaps exceeding 16us. Transmissions from a base station separated by gaps exceeding 16us are considered as separate DL transmission bursts. The base station can perform transmission(s) after the gap without sensing channel availability within the DL transmission burst.

[0154] - UL transmission burst: Defined as a set of transmissions from a terminal without gaps exceeding 16us. Transmissions from a terminal separated by gaps exceeding 16us are considered as separate UL transmission bursts. The terminal may perform transmission(s) after the gap without sensing channel availability within the UL transmission burst.

[0155] - Discovery Burst: Refers to a DL transmission burst comprising a set of signal(s) and / or channel(s) limited within a (time) window and associated with a duty cycle. In an LTE-based system, the discovery burst is a transmission(s) initiated by a base station, comprising PSS, SSS, and CRS (cell-specific RS), and may further comprise a non-zero power CSI-RS. In an NR-based system, the discovery burst is a transmission(s) initiated by an equipment station, comprising at least an SS / PBCH block, and may further comprise a CORESET for a PDCCH scheduling a PDSCH having SIB1, a PDSCH carrying SIB1, and / or a non-zero power CSI-RS.

[0156] FIG. 11 illustrates a method for occupying resources in an unlicensed band. According to regional regulations for unlicensed bands, a communication node within an unlicensed band must determine whether other communication node(s) are using the channel before transmitting a signal. Specifically, the communication node may first perform Carrier Sensing (CS) before transmitting a signal to determine whether other communication node(s) are transmitting a signal. A case where it is determined that other communication node(s) are not transmitting a signal is defined as a Clear Channel Assessment (CCA). If there is a predefined or higher-layer (e.g., RRC) CCA threshold, the communication node may determine the channel state as busy if energy higher than the CCA threshold is detected in the channel, and as idle otherwise. For reference, the CCA threshold in the Wi-Fi standard (802.11ac) is specified as -62dBm for non-Wi-Fi signals and -82dBm for Wi-Fi signals. If the channel state is determined to be idle, the communication node can start signal transmission at the UCell. The aforementioned series of processes may be referred to as LBT (Listen-Before-Talk) or CAP (Channel Access Procedure). LBT, CAP, and CCA may be used interchangeably.

[0157] Specifically, for downlink reception / uplink transmission in an unlicensed band, one or more of the CAP methods described below may be used in a wireless communication system associated with the present invention.

[0158] Method of transmitting downlink signals through unlicensed band

[0159] A base station may perform one of the following unlicensed band access procedures (e.g., Channel Access Procedure, CAP) for downlink signal transmission in an unlicensed band.

[0160] (1) Type 1 Downlink CAP Method

[0161] In a Type 1 DL CAP, the length of the time interval spanned by the sensing slot sensed idle before the transmission(s) is random. A Type 1 DL CAP can be applied to the following transmissions.

[0162] - (i) a unicast PDSCH having user plane data, or (ii) a unicast PDSCH having user plane data and a unicast PDCCH scheduling user plane data, or, transmission(s) initiated by a base station, comprising,

[0163] - Transmission(s) initiated by a base station having (i) only a discovery burst, or (ii) a discovery burst multiplexed with non-unicast information.

[0164] Figure 12 is a flowchart of the CAP operation for downlink signal transmission through the unlicensed band of a base station.

[0165] Referring to FIG. 12, the base station first senses whether the channel is in a deferred state during a sensing slot period of defer duration Td, and then, when counter N becomes 0, can perform transmission (S1234). At this time, counter N is adjusted by sensing the channel during additional sensing slot period(s) according to the procedure below:

[0166] Step 1)(S1220) Set N=Ninit. Here, Ninit is a random value uniformly distributed between 0 and CWp. Then proceed to Step 4.

[0167] Step 2)(S1240) If N>0 and the base station chooses to decrease the counter, set N=N-1.

[0168] Step 3) (S1250) Sensing the channel during the additional sensing slot interval. At this time, if the additional sensing slot interval is idle (Y), move to Step 4. If not (N), move to Step 5.

[0169] Step 4) (S1230) If N=0 (Y), terminate the CAP procedure (S1232). Otherwise (N), proceed to Step 2.

[0170] Step 5) (S1260) Sensing the channel until a busy sensing slot is detected within an additional delay interval Td, or until all sensing slots within an additional delay interval Td are detected as idle.

[0171] Step 6) (S1270) If the channel is sensed as idle during all sensing slot intervals of the additional delay interval Td (Y), proceed to Step 4. Otherwise (N), proceed to Step 5.

[0172] Table D2 illustrates how the mp, minimum contention window (CW), maximum CW, maximum channel occupancy time (MCOT), and allowed CW sizes applied to CAP vary depending on the channel access priority class.

[0173]

[0174] The delay interval Td consists of the sequence of interval Tf (16us) + mp consecutive sensing slot intervals Tsl (9us). Tf includes the sensing slot interval Tsl at the start of the 16us interval.

[0175] CWmin,p <= CWp <= CWmax,p. CWp is set to CWp = CWmin,p and can be updated prior to Step 1 (CW size update) based on HARQ-ACK feedback (e.g., ACK or NACK ratio) for the previous DL burst (e.g., PDSCH). For example, based on HARQ-ACK feedback for the previous DL burst, CWp can be initialized to CWmin,p, increased to the next highest allowed value, or the existing value can be kept.

[0176] (2) Type 2 Downlink (DL) CAP method

[0177] In a Type 2 DL CAP, the length of the time interval spanned by the sensing slot that is sensed idle before the transmission(s) is deterministic. Type 2 DL CAPs are classified into Type 2A / 2B / 2C DL CAPs.

[0178] Type 2A DL CAP can be applied to the following transmissions. In Type 2A DL CAP, the base station can transmit immediately after the channel is sensed as idle for at least a sensing interval Tshort_dl=25us. Here, Tshort_dl consists of an interval Tf (=16us) and a single sensing slot interval immediately following it. Tf includes a sensing slot at the beginning of the interval.

[0179] - (i) having only a discovery burst, or (ii) having a discovery burst multiplexed with non-unicast information, transmission(s) initiated by a base station, or,

[0180] - Base station transmission(s) after a 25us gap from transmission(s) by the terminal within shared channel occupancy.

[0181] Type 2B DL ​​CAP is applicable to transmission(s) performed by the base station after a 16 µs gap from transmission(s) by the terminal within the shared channel occupancy time. In Type 2B DL ​​CAP, the base station can transmit immediately after the channel is sensed as idle for Tf=16 µs. Tf includes a sensing slot within the last 9 µs of the interval. Type 2C DL CAP is applicable to transmission(s) performed by the base station after a maximum 16 µs gap from transmission(s) by the terminal within the shared channel occupancy time. In Type 2C DL CAP, the base station does not sense the channel before performing the transmission.

[0182] Uplink signal transmission method through unlicensed band

[0183] The terminal performs a Type 1 or Type 2 CAP for uplink signal transmission in an unlicensed band. Generally, the terminal can perform a CAP (e.g., Type 1 or Type 2) set by the base station for uplink signal transmission. For example, the terminal may include CAP type indication information within a UL grant (e.g., DCI format 0_0, 0_1) that schedules a PUSCH transmission.

[0184] (1) Type 1 Uplink (UL) Cap Method

[0185] In a Type 1 UL CAP, the length of the time interval spanned by the sensing slot sensed idle before the transmission(s) is random. A Type 1 UL CAP can be applied to the following transmissions.

[0186] - Scheduled and / or configured PUSCH / SRS transmission(s) from the base station

[0187] - Scheduled and / or configured PUCCH transmission(s) from the base station

[0188] - Transmission(s) related to RAP (Random Access Procedure)

[0189] Figure 13 is a flowchart of the Type 1 CAP operation of a terminal for uplink signal transmission.

[0190] Referring to FIG. 13, the terminal first senses whether the channel is in a deferred state during a sensing slot period of defer duration Td, and then, when counter N becomes 0, can perform transmission (S1534). At this time, counter N is adjusted by sensing the channel during additional sensing slot period(s) according to the procedure below:

[0191] Step 1)(S1520) Set N=Ninit. Here, Ninit is a random value uniformly distributed between 0 and CWp. Then proceed to Step 4.

[0192] Step 2)(S1540) If N>0 and the terminal chooses to decrease the counter, set N=N-1.

[0193] Step 3) (S1550) Sensing the channel during the additional sensing slot interval. At this time, if the additional sensing slot interval is idle (Y), move to Step 4. If not (N), move to Step 5.

[0194] Step 4) (S1530) If N=0 (Y), terminate the CAP procedure (S1532). Otherwise (N), proceed to Step 2.

[0195] Step 5) (S1560) Sensing the channel until a busy sensing slot is detected within an additional delay interval Td, or until all sensing slots within an additional delay interval Td are detected as idle.

[0196] Step 6) (S1570) If the channel is sensed as idle during all sensing slot intervals of the additional delay interval Td (Y), proceed to Step 4. Otherwise (N), proceed to Step 5.

[0197] Table 6 illustrates how the mp, minimum CW, maximum CW, Maximum Channel Occupancy Time (MCOT), and allowed CW sizes applied to CAP vary depending on the channel access priority class.

[0198]

[0199] The delay interval Td consists of the sequence of interval Tf (16us) + mp consecutive sensing slot intervals Tsl (9us). Tf includes the sensing slot interval Tsl at the start of the 16us interval.

[0200] CWmin,p <= CWp <= CWmax,p. CWp is set to CWp = CWmin,p and may be updated prior to Step 1 (CW size update) based on the explicit / implicit reception response to the previous UL burst (e.g., PUSCH). For example, based on the explicit / implicit reception response to the previous UL burst, CWp may be initialized to CWmin,p, increased to the next highest allowed value, or retained at its existing value.

[0201] Type 2 Uplink (UL) Cap Method

[0202] In Type 2 UL CAP, the length of the time interval spanned by the sensing slot sensed as idle prior to the transmission(s) is deterministic. Type 2 UL CAP is classified into Type 2A / 2B / 2C UL CAP. In Type 2A UL CAP, the terminal can transmit immediately after the channel is sensed as idle for at least a sensing interval Tshort_dl = 25us. Here, Tshort_dl consists of an interval Tf (= 16us) and a single sensing slot interval immediately following it. In Type 2A UL CAP, Tf includes a sensing slot at the beginning of the interval. In Type 2B UL CAP, the terminal can transmit immediately after the channel is sensed as idle for a sensing interval Tf = 16us. In Type 2B UL CAP, Tf includes a sensing slot within the last 9us of the interval. In Type 2C UL CAP, the terminal does not sense the channel before performing transmission.

[0203] RB Interlace

[0204] FIG. 14 illustrates RB interlacing. In a shared spectrum, considering regulations related to Occupied Channel Bandwidth (OCB) and Power Spectral Density (PSD), a set of (single) discontinuous (equally spaced) RBs in frequency can be defined as a unit resource used / allocated for UL (physical) channel / signal transmission. For convenience, this set of discontinuous RBs is defined as "RB interlacing" (simply interlacing).

[0205] Referring to FIG. 14, multiple RB interlacs (simply interlacs) may be defined within a frequency band. Here, the frequency band includes a set of (wideband) cell / CC / BWP / RB, and the RB may include PRB. For example, an interlac #m∈{0, 1, ..., M-1} may be composed of (common) RBs {m, M+m, 2M+m, 3M+m, ...}. M represents the number of interlacs. A transmitter (e.g., a terminal) may transmit a signal / channel using one or more interlacs. The signal / channel may include PUCCH or PUSCH.

[0206] PUCCH transmission in unlicensed band

[0207] The contents examined above (NR frame structure, RACH, U-Band system, etc.) can be applied in combination with the methods proposed in the present invention described below, or can be supplemented to clarify the technical features of the methods proposed in the present invention.

[0208] Furthermore, the methods related to the PRACH preamble design described below relate to uplink transmission and can be equally applied to the uplink signal transmission methods in the U-Band system (unlicensed band) described earlier; it goes without saying that the technical concept proposed in this specification can be modified or replaced to suit the terms, expressions, structures, etc. defined by each system so that it can be implemented in the respective system.

[0209] For example, uplink transmission via methods related to PUCCH transmission described below can be performed in an L-cell and / or U-cell defined in a U-Band system.

[0210] As previously explained, the CCA threshold in the Wi-Fi standard (802.11ac) is defined as -62dBm for non-Wi-Fi signals and -82dBm for Wi-Fi signals. In other words, the STA (Station) or AP (Access Point) of a Wi-Fi system does not transmit signals in a specific band when a signal from a device not belonging to the Wi-Fi system is received at a power of -62dBm or higher in that specific band.

[0211] In the following, 'unlicensed band' may be replaced and used interchangeably with 'shared spectrum'.

[0212] As shown in Table 4 described above, in a conventional NR system, the PUCCH format consists of five types, from PUCCH format 0 to PUCCH format 4. PUCCH formats 0, 1, and 4 are configured to occupy 1 PRB, and PUCCH formats 2 and 3 are configured to occupy OFDM symbols in PRBs 1 to 16.

[0213] In the following, a PUCCH format used for shared spectrum is proposed. When a specific device (and / or node) transmits a signal in shared spectrum, there may be constraints regarding Power Spectral Density (PSD). For example, according to ETSI regulations, signal transmission in a specific band must satisfy a PSD of 10 dBm / 1 MHz. If a 15 kHz SCS is set, transmitting a PUCCH in PUCCH format 0 (1 PRB, 180 kHz) may result in a maximum allowable power of approximately 10 dBm for the PUCCH. Generally, the maximum power of a terminal is 23 dBm, so 10 dBm corresponds to an allowable power significantly lower than 23 dBm. If a terminal transmits a UL signal at 10 dBm, the maximum UL coverage that the terminal can support may be reduced. If a terminal increases transmission power by transmitting PUCCH in a wider frequency domain (F-domain), it can help solve the problem of reduced UL coverage. Additionally, as a regulation regarding shared spectrum, there may be constraints from the perspective of Occupied Channel Bandwidth (OCB). For example, when a specific device transmits a signal, that signal may need to occupy at least 130% of the system bandwidth. If the system bandwidth is 20 MHz, the signal transmitted by the specific device may need to occupy at least 16 MHz, which is 80% of 20 MHz.

[0214] As a structure for PUCCH that considers regulations regarding PSD and OCB, the previously described RB interlaced structure may be used. For example, a PUCCH sequence configured to use 1 PRB, such as PUCCH format 0 and / or 1, can be constructed by repeating it on PRBs that are spaced apart by a specific interval in the frequency domain, taking into account OCB. When transmitting a PUCCH via RB interlacing, the same PUCCH sequence is transmitted repeatedly. Through repeated transmission, the PAPR (Peak to Average Power Ratio) and CM (Cube Metric) values ​​can be increased. Transmission performance can be improved as PAPR and CM values ​​are lower. Below, methods are proposed for selecting the CS value and / or PS (Phase Shift) value of the PUCCH sequence for each repeated transmission, taking into account PAPR and CM, when a PUCCH is transmitted via RB interlacing in the frequency domain.

[0215] In addition, the methods proposed in this specification may be used in use cases other than NR U-band. As an example of another use case, the methods proposed in this specification may be used in NR-based non-terrestrial networks (NTN).

[0216] Below, we will explain in detail how to allocate frequency resources for NR sidelinks in the unlicensed band.

[0217] Channel sensing interval control for NR sidelink in unlicensed band

[0218] The terminal may perform transmission and / or reception operations of sidelink signals in an unlicensed band. Transmission and / or reception operations of sidelink signals in an unlicensed band may be preceded by channel sensing operations (e.g., energy detection / measurement) for the channel to be used in accordance with band-specific regulations and / or requirements. The terminal may perform transmission and / or reception of sidelink signals in the unlicensed band if, based on the result of the channel sensing, the channel or RB set to be used is determined to be IDLE (e.g., when the measured energy is below or less than a specific threshold). Conversely, if, based on the result of the channel sensing, the channel or RB set to be used is determined to be BUSY (e.g., when the measured energy is above or exceeds a specific threshold), the terminal may cancel all or part of the transmission to the unlicensed band.

[0219] Meanwhile, in operation in the unlicensed band, the channel sensing operation may be omitted or simplified (making the channel sensing interval relatively small) within a certain time period after transmission for a specific time interval of the terminal. Conversely, if a certain time has elapsed after the transmission of the sidelink signal, the performance of the general channel sensing operation described above is required, and whether to transmit the sidelink signal in the unlicensed band may be determined after the performance of the general channel sensing operation.

[0220] Alternatively, transmission in an unlicensed band may, depending on regulations or requirements, involve the size of the time interval and / or frequency occupancy area and / or power spectral density (PSD) of the signal / channel transmitted by the terminal being above a certain level. In other words, transmission of a sidelink signal in an unlicensed band may be regulated by the size of the time / frequency resources and / or power size (or power spectral density) for the sidelink signal, depending on regulations or requirements. For example, the terminal may transmit a sidelink signal in the unlicensed band with a size of the time interval and / or frequency occupancy area of ​​the signal / channel and / or power spectral density (PSD) above a certain level.

[0221] Alternatively, in an unlicensed band, the terminal may notify the occupancy of a channel secured through initial general channel sensing for a certain period of time through COT (channel occupancy time) interval information, thereby simplifying channel sensing. Here, the maximum value of the COT interval length may be set differently depending on the priority value of the service or data packet.

[0222] Meanwhile, the base station can share the COT interval it has secured through channel sensing in the form of DCI transmission. The terminal can perform a specific (instructed) channel sensing type and / or CP EXTENSION within the COT interval based on the DCI information received from the base station. Here, the terminal can share the COT interval it has secured through channel sensing with the base station that is the recipient of the UL transmission. Information related to the above COT interval can be provided to the base station via UL through CG-UCI. In this case, the base station could perform simplified channel sensing within the COT interval shared from the terminal. Meanwhile, in the case of sidelink communication, the terminal can perform sidelink transmission and reception by receiving instructions from the base station regarding resources to be used for sidelink transmission via DCI or RRC signaling, as in Mode 1 RA operation, or by selecting transmission resources through sensing operations between terminals without the assistance of the base station, as in Mode 2 RA operation.

[0223] Meanwhile, in the case of channel access type 1, which can be used regardless of COT (channel occupancy time) settings, the procedure shown in Table 7 can be performed for DL ​​transmission, and the procedure shown in Table 8 can be performed for UL transmission.

[0224]

[0225]

[0226] Meanwhile, within the COT (channel occupancy time), simplified channel access type 2 could be used before transmission, and for DL ​​transmission, the procedure shown in Table 9 could be performed, and for UL transmission, the procedure shown in Table 10 could be performed.

[0227]

[0228]

[0229] The method of TYPE 2A DL and / or UL channel access described in Tables 7 through 10 can be similarly applied to sidelink communication (SL) for unlicensed bands.

[0230] Specifically, TYPE 2A SL (SideLink) channel access is T in the same way as TYPE 2A DL and / or UL channel access short_sl A sensing interval of =25us, and the above interval is T f It is composed of a single sensing slot immediately following (=16us), and T f It may be in the form of including a sensing slot at the beginning. Basic IDLE determination may also be performed in the same or similar manner as DL or UL.

[0231] Or, TYPE 2B SL channel access is in the same manner as TYPE 2B DL ​​and / or UL channel access as the above T f SL transmission can be performed immediately after idle state is sensed within the period (=16us). The above T f A sensing slot can be configured within the last 9 us. Basic IDLE determination can also be performed in the same or similar manner as DL or UL.

[0232] Alternatively, TYPE 2C SL channel access may be a form that does not perform channel sensing in the same way as TYPE 2C DL and / or UL channel access. However, the time interval of SL transmission may be up to 584us.

[0233] Alternatively, TYPE 1 SL channel access can derive a random integer value N based on the size of the contention window (CW) corresponding to the priority class in the same way as TYPE 1 DL and / or UL channel access. T corresponding to the priority class dWhen the channel sensing result for the size DEFER DURATION is IDLE, T sl The N-1 counter value is decreased in the case of IDLE, and if the counter value is 0, the terminal can occupy the RB set or channel that is the target of channel sensing. In contrast, the above T sl If part of the channel sensing results for the interval is determined to be BUSY, then T again d Channel sensing can be continued by maintaining the counter value until the channel sensing result of the size's DEFER DURATION unit becomes idle. The above T d The length DEFER DURATION is T f (=16us) after m p T's sl This can be a continuously configured form, where, m p is a value determined by PRIORITY CLASS p, and T sl (=9us) may be the time interval during which channel sensing is performed.

[0234] Alternatively, if the terminal is occupying the channel via TYPE 1 SL channel access and a sidelink transmission is not ready to be transmitted, the terminal places a T immediately before the sidelink transmission that is ready for transmission. d Length DEFER DURATION and T slA sensing interval of length can be set, and if both are IDLE, the sidelink transmission can be performed immediately. Alternatively, if at least one is BUSY, TYPE 1 SL channel access can be performed again. Or, if sidelink transmission is difficult at the time when channel sensing ends (e.g., the time when channel sensing ends is after the time when sidelink transmission starts), the terminal can re-select the sidelink transmission resource. Here, the re-selection of the resource can be performed by considering the time when channel sensing ends and / or the length of the remaining sensing interval. For example, the remaining sensing interval may be a value derived by assuming that channel sensing is in an idle state (IDLE).

[0235] Alternatively, the supported channel access types may differ depending on the type of sidelink channel (e.g., PSCCH / PSSCH, S-SSB, and / or PSFCH). For example, TYPE 1 SL channel access and / or TYPE 2 series channel access may be allowed or supported for PSCCH / PSSCH transmission, and all (or part) of the TYPE 2 series channel access may be allowed or supported for S-SSB and / or PSFCH. Alternatively, depending on the type of sidelink channel (e.g., PSCCH / PSSCH, S-SSB, and / or PSFCH), T in the above TYPE 1 SL channel access f , m p , and / or m sl (Value) may be set differently. For example, the above T f , m p , and / or m sl (Value) can be predefined or (pre-set) by SL priority, sidelink channel type, and / or CAPC (channel access priority class, p).

[0236] Meanwhile, for TYPE 1 DL and / or UL channel access, the CW magnitude can be updated based on feedback signals. Although the CW magnitude can also be updated based on feedback signals in TYPE 1 SL channel access, unlike DL and / or UL, SL may receive multiple ACK / NACKs based on group cast or receive only NACK feedback signals; therefore, it is necessary to redefine the method for updating the CW magnitude for the sidelink in consideration of these factors. Below, a method for updating the CW magnitude considering the HARQ feedback characteristics of the sidelink signal is explained in detail.

[0237] FIG. 15 is a diagram illustrating a method for updating the size of a contention window based on a sidelink feedback signal in an unlicensed band.

[0238] When sidelink HARQ feedback is enabled (or activated) for group cast, the terminal can determine whether to send HARQ feedback based on TX / RX distance and / or RSRP. For non-CBG operation, two HARQ-ACK feedback options may be supported. For example, sidelink HARQ feedback may be enabled as HARQ-ACK feedback option 1 or HARQ-ACK feedback option 2.

[0239] Referring to FIG. 15 (a), the terminal can transmit or group-cast a sidelink signal (PSCCH / PSSCH) associated with HARQ-ACK feedback option 1. Group-cast option 1 is a case where only the HARQ feedback of NACK is enabled, and among the group-casted receiving terminals, only the receiving terminal that failed to decode the sidelink signal (or the transmission block associated with PSCCH) can transmit PSFCH, which is the HARQ feedback signal of NACK. In contrast, among the group-casted receiving terminals, the receiving terminal that succeeded in decoding the sidelink signal (or decoding the transmission block (TB) associated with PSCCH) does not transmit the HARQ feedback signal of ACK.

[0240] Referring to FIG. 15 (b), the terminal can transmit or group cast a sidelink signal (PSCCH / PSSCH) associated with group cast option 2. Group cast option 2 is a case where only HARQ feedback of ACK or NACK is enabled. Among the group cast receiving terminals, only the receiving terminal that failed to decode the sidelink signal (or decode the transmission block associated with PSCCH) transmits PSFCH, which is the HARQ feedback signal of NACK, and the receiving terminal that succeeded in decoding the sidelink signal (or decoding the transmission block associated with PSCCH) transmits PSFCH, which is the HARQ feedback signal of ACK.

[0241] Accordingly, in the case of a sidelink, SL HARQ-ACK feedback may be disabled, or multiple feedback signals may be received. For example, in the case of a specific SL HARQ-ACK feedback option, the receiving terminal may transmit a NACK only when the decoding (TB decoding) of the received signal fails, and may not transmit SL HARQ-ACK feedback when the decoding (TB decoding) of the received signal is successful. Alternatively, in the case of a specific SL HARQ-ACK feedback option, multiple feedback signals may be received regarding the transmission of the sidelink signal. Thus, in the case where only NACK is fed back in the sidelink communication and / or where multiple ACK / NACKs are received, it is necessary to adjust the size of the contention window (CW) for the sidelink communication differently from the methods of DL or UL. For example, in the case of sidelink communication, the size of the contention window (CW) p Whether to change or update ) may be determined differently depending on the aforementioned groupcast HARQ-ACK feedback option (or groupcast options 1 and 2).

[0242] (1) For GroupCast HARQ-ACK Feedback Option 1

[0243] The above terminal can transmit a sidelink signal associated with Group Cast HARQ-ACK feedback option 1 (or Group Cast option 1), and based on the feedback signal associated with Group Cast HARQ-ACK feedback option 1, the size of the contention window (CW) for all (or specific) CAPCs (p) p ) can be updated or changed. Here, the terminal may receive only NACK as a feedback signal for the sidelink signal.

[0244] Specifically, the terminal CW for all (or specific) CAPCs (p) when the feedback signal(s) based on the groupcast HARQ-ACK feedback option 1 are determined (or considered) to be an ACK (e.g., when the absence of a feedback signal (PSFCH) for the PSCCH / PSSCH transmitted by the terminal can be considered an ACK situation). p may be initialized to (and / or maintained) a minimum value. In other words, in the case based on the groupcast HARQ-ACK feedback option 1, the terminal, based on the fact that a feedback signal for the sidelink signal was not received (considering that a feedback signal for the ACK was received), CW for all (or specific) CAPCs (p). p can be initialized to (and / or maintained) a minimum value. Alternatively, if a feedback signal of the NACK is received, the terminal may use the CW p It can be increased by a pre-set allowable value.

[0245] Or, if the SL HARQ-ACK feedback is received that includes a NACK in which the RSRP (Reference Signals Received Power) measurement value based on the SL HARQ-ACK feedback signal is below (or less than) a specific threshold (e.g., a preset value), the terminal [receives] a CW for all (or specific) CAPCs (p). p may be initialized to (and / or maintained) a minimum value. In other words, if the terminal receives a feedback signal containing the NACK with a reception strength below a preset specific threshold (considering it not to be a feedback signal of a valid NACK), the terminal [can] CW for all (or specific) CAPCs (p). pmay be initialized to (and / or maintained) a minimum value. Alternatively, if a feedback signal including the NACK is received with a strength greater than the specific threshold, the terminal may reduce the size of the contention window (CW p ) can be increased by a pre-set allowable value.

[0246] Or, if N PSCCH / PSSCH based on Group Cast HARQ-ACK Feedback Option 1 are transmitted during a specific time interval, and (and / or) the number of SL HARQ-ACK feedbacks determined to be NACK among the N PSCCH / PSSCHs is M or less (or less), then the terminal [performs] CW for all (or specific) CAPCs (p). p can be initialized (and / or maintained) to a minimum value. Here, the value of N may be 1 or greater, and the specific time interval may be a reference duration for determining the CW (CONTENTION WINDOW) or may be determined based on the reference duration. Alternatively, the value of M may be predefined (and / or set). For example, the value of M may be derived in the form of multiplying a ratio to N, and the ratio value may be predefined (and / or set). Alternatively, if M or more (or exceeding) NACKs are determined in relation to multiple PSCCH / PSSCHs for the group cast HARQ-ACK feedback option 1, the terminal may increase the CW for all (or specific) CAPCs (p) by a predetermined or defined allowable value. pEach can be reset or updated. Here, the determination of M or more NACKs may be determined based on whether NACKs are received consecutively for the group cast PSCCH / PSSCH (or, it may be limited to cases where M or more NACKs are received consecutively). For example, if there is a PSCCH / PSSCH transmission determined to be an ACK between PSCCH / PSSCH transmissions determined to be NACKs, the terminal may count the number of NACKs again starting from after the PSCCH / PSSCH transmission determined to be an ACK.

[0247] (2) For GroupCast HARQ-ACK Feedback Option 2

[0248] The terminal may transmit a sidelink signal associated with Group Cast HARQ-ACK feedback option 2 (or Group Cast option 2) and may update or change the size of the contention window (CWp) for all (or specific) CAPCs (p) based on the feedback signal associated with Group Cast HARQ-ACK feedback option 2. In this case, the terminal may receive multiple feedback signals including ACK or NACK for the sidelink signal from multiple terminals.

[0249] Specifically, when the terminal transmits a sidelink signal associated with GroupCast HARQ-ACK feedback option 2, the size of the contention window (CW) for all (or specific) CAPCs (p) is based on at least one feedback signal including ACK among a plurality of feedback signals. pIt can determine whether to change or update ). For example, the terminal may determine the size of the contention window (CW) for all or specific CAPCs (p) based on a feedback signal based on Group Cast HARQ-ACK Feedback Option 2 (Group Cast Option 2) (i.e., when receiving SL HARQ-ACK feedbacks (or feedback signals) from multiple PSCCH / PSSCH receiving terminals based on Group Cast HARQ-ACK Feedback Option 2). p It can determine whether to change (or reset) ). Specifically, the terminal determines the CW for all (or specific) CAPCs (p) when all SL HARQ-ACK feedbacks are ACKs. p may be initialized to (and / or maintained) a minimum value. Alternatively, the terminal may initialize (and / or maintain) the CW for all (or specific) CAPCs (p) to a minimum value when at least one of the SL HARQ-ACK feedbacks is an ACK. p ...can be changed or updated. Or, the terminal [can] for all (or specific) CAPCs (p) if the ratio of HARQ-ACK feedback of ACK among the received SL HARQ-ACK feedbacks is above (or exceeds) a specific threshold. p It can be initialized to (and / or maintained) a minimum value. For example, the specific threshold value may be a predefined value (e.g., 10% or 20%) and / or a value that is set (in advance).

[0250] Or, the terminal determines the size of the contention window (CW) for all (or specific CAPC p) based on the received CSI report in response to the PSCCH / PSSCH requesting the CSI report. p It can determine whether to change (reset) ). For example, when the terminal successfully receives a CSI report corresponding to a PSCCH / PSSCH requesting a CSI report, the size of the contention window (CWp ) may be initialized to (and / or maintained) a minimum value. Alternatively, if the above CSI report is not successfully received, the terminal may set the size of the contention window (CW p ) can be increased by a pre-set allowable value.

[0251] Or, if the terminal transmits a PSCCH / PSSCH requesting inter-UE coordination information, the size of the contention window (CW) for all (or specific CAPC p) based on whether the inter-UE coordination information was successfully received. p It can determine whether to change (reset) ). For example, when the terminal successfully receives the coordination information between the terminals, the size of the contention window (CW p ) can be initialized to (and / or maintained) a minimum value. Alternatively, if the coordination information between the terminals is not successfully received, the terminal may use the size of the contention window (CW p ) can be increased by a pre-set allowable value.

[0252] Or, if the terminal transmits a PSCCH / PSSCH with HARQ-ACK feedback disabled, the terminal determines the size of the contention window (CW) for all (or specific CAPC p) based on the cumulative (re)transmission count for the same TB. p It can determine whether to change (reset) ). For example, the terminal can determine whether to change (reset) the size of the contention window (CW) when the cumulative number of (re)transmissions for the same TB is less than or equal to a predefined value (or a (pre)set value). p ) can be initialized to (and / or maintained) a minimum value. Or, the terminal may (re)transmit at a multiple of a defined value (or, a (pre)set value) the size of the contention window (CW pThe value of ) can be increased to the next allowed value. Or, whenever the number of (re)transmissions exceeds a multiple of the defined value, the terminal may increase the size of the contention window (CW p The value of ) can be increased to the next allowable value. Here, the size of the competition window (CW p Increasing ) to the next allowable value is due to the size of the contention window (CW) of the terminal caused by other factors. p It may be omitted when ) is initialized (and / or maintained) to a minimum value. Alternatively, even if a PSCCH / PSSCH with HARQ-ACK feedback disabled is transmitted, the receiving terminal may be requested to transmit an ACK only upon successful decoding of said PSCCH / PSSCH. In this case, when the terminal receives an ACK from the receiving terminal, the size of the contention window (CW) for all (or specific CAPC p) p ) may be initialized to (and / or maintained) a minimum value. Meanwhile, a terminal receiving such an ACK may ignore the ACK in relation to HARQ process management. Alternatively, if a PSCCH / PSSCH with HARQ-ACK feedback disabled is transmitted, the terminal may [remove] the size of the contention window (CW p Randomly select the size of the contested window (CW) from the candidate pool for ) p You can select ).

[0253] Or, the terminal may determine the size of the contention window (CW) for all (or specific CAPC p) based on the PSFCH it transmitted. p It can determine whether to update (reset) ). For example, the terminal can determine whether to update (reset) the size of the contention window (CW) when sidelink control information (SCI) corresponding to the SOURCE ID, DESTINATON ID, CAST TYPE, and / or HARQ PROCESS NUMBER corresponding to the TB corresponding to the PSFCH is received, or (and / or) when NDI is toggled in the SCI. p) may be initialized to (and / or maintained) its initial value. Or, if the terminal has not received an SCI corresponding to the SOURCE ID, DESTINATON ID, CAST TYPE, and / or HARQ PROCESS NUMBER corresponding to the TB corresponding to the PSFCH, or (and / or) if NDI has not been toggled in the received SCI, the size of the contention window (CW p ) can be increased (or maintained) to the next allowed value.

[0254] The size of the aforementioned competition window (CW p The method for determining ) may involve the application of a combination of multiple methods. For example, in cases where there are multiple SL HARQ-ACK feedback groups referenced above, the result determined based on the representative HARQ-ACK value of each group is the size of the contention window (CW) for all CAPCs (or for each CAPC). p If ) is not maintained (and / or initialized to an initial value), the terminal [is subject to] the size of all (or, per each CAPC) contention windows (CW p ) can be increased to the next allowed value.

[0255] Or, as described above, the size of the competition window (CW p There may be various factors serving as the basis for (re)setting or determining ). In this case, the result determined for each factor is the size of the competition window (CW p Cases where ) is increased to the next allowable value and the size of the contention window (CW p Cases where ) is maintained (or initialized) may occur simultaneously. In this case, the terminal may have the size of the contention window (CW p ) can be maintained (and / or CW_p value initialized to the minimum). Alternatively, the result determined for each factor is the size of the competition window (CW p Cases where ) is increased to the next allowable value and the size of the contention window (CW pIf the case of maintaining (or initializing) occurs simultaneously, the terminal [is] the size of the contention window (CW p ) can be increased to the next allowed value.

[0256] Or, the size of the competition window (CW p The PSCCH / PSSCH considered in determining ) may be received within a specific time interval. Here, the specific time interval is the size of the contention window (CW) of the terminal p It may exist within the fastest SL channel occupancy interval after the last update (or, change, reset).

[0257] Or, the size of the aforementioned competition window (CW p The behavior of initializing ) to a minimum value may be replaced with another specific value (e.g., a (pre-)set value). and / or, said specific value is the size of the contention window (CW p It may be set differently depending on the factors controlling ).

[0258] Alternatively, the reference period (REFERENCE DURATION) may be a period from the start of channel occupancy for the COT secured by the terminal (for sidelink communication) and / or the COT secured by the base station (for sidelink communication) until a specific point in time. The specific point in time may be the first end point of the first slot where the actual specific sidelink transmission is performed for all allocated resources for sidelink transmission, the second end point of the first transmission burst containing the actual specific sidelink transmission for all allocated resources for sidelink transmission, or the earlier of the first end point and the second end point. Here, the specific sidelink transmission may be a PSCCH / PSSCH transmission for unicast and / or groupcast, or a PSCCH / PSSCH transmission with SL HARQ-ACK feedback enabled. Alternatively, the length of the reference period may be set (in advance) per resource pool and / or per SL priority value of the terminal's SL transmission when the COT is initialized.

[0259] Alternatively, the methods described above may be combined differently depending on whether the COT section described above is initialized by the terminal or by the base station.

[0260] Or, the size of the competition window (CW) for the above side link pAdjusting the size of the CW can be performed for each unicast session (group), each cast type, each transmission priority value, each SL transmission with SL HARQ-ACK feedback enabled / disabled, and / or each SL HARQ-ACK feedback option. For example, the process of adjusting the size of the CW can be performed independently of each other when the first terminal transmits a sidelink signal to the second terminal via the first sidelink and when the first terminal transmits a sidelink signal to the third terminal via the second sidelink. Alternatively, when the size of the HARQ-ACK-based CONTENTION WINDOW is adjusted, the HARQ-ACK may be limited to a specific cast type and / or a specific unicast session.

[0261] Or, the size of the competition window (CW) for the above side link p Adjusting ) may be performed only based on a specific cast type (e.g., unicast or group cast) and / or PSSCH with SL HARQ-ACK feedback enabled.

[0262] Or, the size of the competition window (CW p Initializing the value of ) to each minimum value is the size of the contention window (CW p It can be applied by replacing it with decreasing the value of ) to the previous allowed value.

[0263] Or, when TYPE 1 SL channel access is performed, the size of the contention window (CW p ) can be set (in advance) by PRIORITY CLASS, by SL priority, and / or by resource pool. For example, in the above case, the size of the contention window (CW p ) being adjusted (separately) may not be performed by the terminal.

[0264] Alternatively, when performing a sensing operation on a channel according to a channel access type, a threshold value for determining whether the channel is BUSY or IDLE may be set (and / or defined in advance) by resource pool, by SL BWP, by RB set, by carrier, by SL transmission priority, by representative transmission power value (range), and / or by congestion control level.

[0265] Alternatively, the proposed methods described above may be applied in different combinations depending on whether the transmission is within or outside the COT (Channel Occupancy Time). Alternatively, the proposed methods described above may be applied in different combinations depending on the form of the COT (e.g., whether it is a semi-static form or a time-varying form). For example, the semi-static COT may be a case where it is guaranteed that there is no other technology sharing the same channel or RB set for a certain period of time, such as by a regulation. Alternatively, the semi-static COT may be a case where it is guaranteed that there is no DL and / or UL transmission sharing the same channel or RB set for a certain period of time, such as by a regulation, in the case of SL transmission. Alternatively, the semi-static COT may be a case where it is guaranteed that there is no SL transmission sharing the same channel or RB set for a certain period of time, such as by a regulation, in the case of DL and / or UL transmission. Alternatively, the above-mentioned SEMI-STATIC COT may be a case where it is guaranteed that there is no SL transmission based on SL Mode 2 resource (re)selection sharing the same channel or RB set for a certain period of time, such as by regulations. Alternatively, the length of the fixed-frame period (FFP) and / or the time-axis offset value for the above-mentioned SEMI-STATIC COT interval may be (pre-)set per resource pool, per SL BWP, per carrier, per RB set, per congestion control level, and / or per SL transmission priority value. Alternatively, the length of the fixed-frame period (FFP) and / or the time-axis offset value for the above-mentioned SEMI-STATIC COT interval may be set through PC5-RRC signaling between terminals. In this case, the FFP (pre-)set through the PC5-RRC signaling may be overwritten. Alternatively, the FFP set by the PC5-RRC may be applied or used only for unicast transmissions corresponding to the PC5-RRC connection.

[0266] Alternatively, the proposed methods described above may be applied in different combinations depending on the carrier, the presence or absence of guards between RB sets, or the regulations (of the unlicensed band).

[0267] Meanwhile, the proposed methods described above have a contention window size (CW) for all CAPCs. p Although the explanation was based on the premise of changing ), the size of the contention window (CW) for each specific CAPC or SL priority value p It may also be applied with extension even if ) is changed.

[0268] FIGS. 16 and 17 are flowcharts illustrating a method for a first terminal to transmit a sidelink signal based on a contention window in an unlicensed band.

[0269] As described above regarding the transmission of a sidelink signal in an unlicensed band, the first terminal needs to prioritize sensing whether the channel associated with the unlicensed band is idle in order to transmit a sidelink signal in the unlicensed band. To this end, the first terminal based on TYPE 1 SL channel access can perform channel sensing operations based on a CW corresponding to the PRIORITY CLASS, just like TYPE 1 DL and / or UL channel access in Tables 7 and 8. For example, the first terminal can perform channel sensing on a sub-channel unit or a resource block (set) unit, and back off (decrease) the counter value of the backoff counter when a signal of strength greater than a preset threshold is not detected. The first terminal can determine that the sub-channels are idle when the backoff counter expires (0) and transmit the first signal.

[0270] Additionally, the size of the CW may be updated based on a feedback signal. For example, in the case of TYPE 1 DL and / or UL channel access in Tables 7 and 8, depending on whether the feedback signal is ACK or NACK, the size of the CW may be updated to initialize (or maintain) the initial value or increase by a preset allowable value. However, as described above, for the sidelink communication, the feedback may receive multiple feedback signals of ACK or NACK (Group Cast Option 2) for a single signal based on a group cast, or only a feedback signal of NACK (Group Cast Option 1).

[0271] Accordingly, the method for updating the size of the above CW needs to be defined differently depending on whether the HARQ feedback associated with Group Cast Option 1 (or Group Cast HARQ-ACK Feedback Option 1) is activated in relation to the first signal, which is the sidelink signal, or whether the HARQ feedback associated with Group Cast Option 2 (or Group Cast HARQ-ACK Feedback Option 2) is activated, and this will be explained in detail below.

[0272] Referring to FIG. 16, the first terminal can arbitrarily select a value of a back-off counter within a contention window related to an unlicensed band (S201).

[0273] Next, the first terminal may transmit a first signal associated with Group Cast Option 2 in the unlicensed band based on the backoff counter in which the arbitrarily selected value is set (S203). For example, the first terminal may transmit the first signal that enables HARQ (Hybrid Automatic Repeat and request) feedback of ACK or NACK (i.e., the Group Cast Option 2 described above). For example, the first terminal may indicate the activation of HARQ feedback of (Group Cast-based) ACK or NACK in relation to the first signal through sidelink control information (or, first SCI and / or second SCI) associated with the first signal, which is PSSCH, and may transmit the first signal, which is a sidelink shared channel (PSSCH), based on the sidelink control information. Alternatively, the sidelink control information may include a zone ID, a communication range requirement, and / or location information of the first terminal, and based thereon, may receive the feedback signal from a plurality of terminals within a certain range or distance.

[0274] Next, the first terminal can receive feedback signals for the first signal (S205). As described above, the first terminal can determine whether to perform an update to initialize the size of the contention window to an initial value or an update to increase it by a preset allowable value based on the feedback signal (S207).

[0275] Specifically, as described above, the first terminal transmits the first signal with HARQ (Hybrid Automatic Repeat and request) feedback of ACK or NACK enabled (i.e., the group cast option 2 described above), and can receive feedback signals for the first signal from a plurality of terminals. The first terminal can initialize (or maintain) the size of the contention window to an initial value if there is at least one feedback signal containing the ACK among the feedback signals. In other words, if at least one feedback signal containing the ACK is received, the first terminal can initialize (or maintain) the size of the contention window to an initial value regardless of whether the remaining feedback signal is a NACK. That is, in a situation where multiple ACK / NACKs can be received for the first signal in relation to sidelink communication, if only at least one ACK is received, the size of the contention window is initialized to an initial value even if the remaining feedback signal is a NACK. In contrast, for TYPE 1 DL and / or UL channel access in Tables 7 and 8, the size of the contention window can be updated to increase by a preset allowable value upon receipt of NACK.

[0276] Alternatively, if the number of feedback signals including the ACK among the feedback signals is received exceeds a preset number (or exceeds), the first terminal may maintain the size of the contention window or initialize it to an initial value. Alternatively, if the number of feedback signals including the ACK among the feedback signals is received less than a preset number (or is less than or equal to), the size of the contention window may be updated to increase by the next preset allowable value. Alternatively, if the number of feedback signals including the ACK among the feedback signals is less than a preset number, the first terminal may increase the size of the contention window by the preset allowable value. In this case as well, as described above, the reception of NACK may not be considered in the update of the size of the contention window.

[0277] Alternatively, if the ratio of feedback signals including the ACK among the feedback signals (e.g., number of feedback signals including the ACK / number of feedback signals) is greater than or equal to a preset threshold ratio, the first terminal may maintain the size of the contention window or initialize it to an initial value. Conversely, if the ratio of feedback signals including the ACK among the feedback signals is less than a preset threshold ratio, the first terminal may increase the size of the contention window by a preset allowable value.

[0278] Referring to FIG. 17, the first terminal can transmit a first signal associated with group cast option 1 in the unlicensed band (S301). For example, the first signal may be a sidelink signal with only HARQ feedback of the NACK enabled (i.e., a feedback signal containing only HARQ-ACK information of the NACK). Meanwhile, the first terminal can receive a NACK only feedback signal for the first signal from the plurality of terminals (or at least one terminal).

[0279] Next, the first terminal can monitor whether a feedback signal for the first signal is received (S303). Based on the result of the monitoring, the first terminal can determine whether to update the size of the contention window by initializing it to an initial value or by increasing it by a preset allowable value (S305).

[0280] Specifically, the first terminal transmits the first signal with only the HARQ feedback of the NACK enabled (i.e., the group cast option 1 described above) and can receive feedback signals for the first signal from a plurality of terminals. In this case, if feedback signals for the first signal are not received from the plurality of terminals, the first terminal may maintain the size of the contention window or initialize it to an initial value. Alternatively, if even one feedback signal (i.e., including a NACK) is received, the first terminal may update the size of the contention window to increase by the allowable value described above. Or, if the feedback signal (i.e., the feedback signal including a NACK) is received only with a strength below a specific threshold strength, the first terminal may maintain the size of the contention window or initialize it to an initial value. Alternatively, if the feedback signal (i.e., the feedback signal including a NACK) is received with a strength above a specific threshold strength, the first terminal may update the size of the contention window to increase by the allowable value described above.

[0281] Alternatively, the first terminal may transmit the first signal with HARQ feedback disabled. In this case, the first terminal may determine whether to initialize the size of the contention window to an initial value (or maintain the existing value) or update it based on a preset allowable value, based on the number of retransmissions of the same Transport Block (TB) associated with the first signal as described above.

[0282] Alternatively, the first terminal may determine whether to initialize the size of the contention window to an initial value (or maintain the existing value) or update it based on a preset allowable value, based on whether it receives a CSI report in response to the first signal, which is a sidelink signal requesting a CSI (Channel State Information) report. For example, if the first terminal receives a CSI report in response to the first signal, it may initialize the size of the contention window to an initial value (or maintain the existing value).

[0283] Meanwhile, the first terminal can select a transmission resource for transmitting the first signal, and if the selected transmission resource in the time domain precedes the expiration time of the backoff counter, the re-selection of the transmission resource may be triggered.

[0284] In this way, by newly defining a method for updating the contention window that considers the HARQ feedback characteristics for sidelink signals in the unlicensed band, ambiguity regarding the update of the contention window for sidelink communication in the unlicensed band can be resolved. Furthermore, as described above, by clearly presenting criteria for updating the contention window in the unlicensed band based on the number or ratio of feedback signals including ACKs, the contention window can be effectively updated even in sidelink communication where multiple feedback signals corresponding to a single signal exist. Additionally, even when only NACK feedback signals are received in sidelink communication, clear criteria such as the ratio of NACKs or the number of consecutive NACKs can be presented, thereby enabling the contention window to be effectively updated in sidelink communication where only NACK feedback signals are received. Furthermore, the contention window in the unlicensed band can be updated based on whether information corresponding to a CSI report request and / or a request for coordination information between UEs is received in sidelink communication.

[0285] Example of a communication system to which the invention is applied

[0286] Although not limited thereto, the various descriptions, functions, procedures, proposals, methods, and / or flowcharts of the invention disclosed in this document may be applied to various fields requiring wireless communication / connection (e.g., 5G) between devices.

[0287] Examples are provided in more detail below with reference to the drawings. In the following drawings and descriptions, the same reference numerals may represent the same or corresponding hardware blocks, software blocks, or function blocks unless otherwise described.

[0288] FIG. 18 illustrates a communication system to which the present invention is applied.

[0289] Referring to FIG. 18, the communication system (1) to which the present invention applies includes a wireless device, a base station, and a network. Here, the wireless device refers to a device that performs communication using wireless access technology (e.g., 5G NR (New RAT), LTE (Long Term Evolution)) and may be referred to as a communication / wireless / 5G device. Although not limited thereto, the wireless device may include a robot (100a), a vehicle (100b-1, 100b-2), an XR (eXtended Reality) device (100c), a hand-held device (100d), a home appliance (100e), an IoT (Internet of Thing) device (100f), and an AI device / server (400). For example, the vehicle may include a vehicle equipped with wireless communication functions, an autonomous vehicle, a vehicle capable of performing inter-vehicle communication, etc. Here, the vehicle may include an Unmanned Aerial Vehicle (UAV) (e.g., a drone). XR devices include AR (Augmented Reality) / VR (Virtual Reality) / MR (Mixed Reality) devices and can be implemented in the form of HMDs (Head-Mounted Devices), HUDs (Head-Up Displays) equipped in vehicles, televisions, smartphones, computers, wearable devices, home appliances, digital signage, vehicles, robots, etc. Portable devices may include smartphones, smartpads, wearable devices (e.g., smartwatches, smart glasses), computers (e.g., laptops, etc.). Home appliances may include TVs, refrigerators, washing machines, etc. IoT devices may include sensors, smart meters, etc. For example, base stations and networks may be implemented as wireless devices, and a specific wireless device (200a) may operate as a base station / network node to other wireless devices.

[0290] Wireless devices (100a to 100f) can be connected to a network (300) through a base station (200). Artificial Intelligence (AI) technology may be applied to the wireless devices (100a to 100f), and the wireless devices (100a to 100f) can be connected to an AI server (400) through the network (300). The network (300) can be configured using a 3G network, a 4G (e.g., LTE) network, or a 5G (e.g., NR) network. The wireless devices (100a to 100f) may communicate with each other through the base station (200) / network (300), but they may also communicate directly (e.g., sidelink communication) without going through the base station / network. For example, vehicles (100b-1, 100b-2) can communicate directly (e.g., V2V (Vehicle to Vehicle) / V2X (Vehicle to everything) communication). Also, IoT devices (e.g., sensors) can communicate directly with other IoT devices (e.g., sensors) or other wireless devices (100a to 100f).

[0291] Wireless communication / connection (150a, 150b, 150c) can be established between wireless devices (100a~100f) / base station (200) and base station (200) / base station (200). Here, wireless communication / connection can be achieved through various wireless access technologies (e.g., 5G NR), such as uplink / downlink communication (150a), sidelink communication (150b) (or D2D communication), and inter-base station communication (150c) (e.g., relay, IAB (Integrated Access Backhaul)). Through wireless communication / connection (150a, 150b, 150c), wireless devices and base stations / wireless devices, and base stations and base stations can transmit / receive wireless signals to / from each other. For example, wireless communication / connection (150a, 150b, 150c) can transmit / receive signals through various physical channels. To this end, based on various proposals of the present invention, at least some of the following may be performed: various configuration information setting processes for transmitting / receiving wireless signals, various signal processing processes (e.g., channel encoding / decoding, modulation / demodulation, resource mapping / demapping, etc.), resource allocation processes, etc.

[0292] Example of a wireless device to which the present invention is applied

[0293] FIG. 19 illustrates a wireless device that can be applied to the present invention.

[0294] Referring to FIG. 19, the first wireless device (100) and the second wireless device (200) can transmit and receive wireless signals through various wireless access technologies (e.g., LTE, NR). Here, {the first wireless device (100), the second wireless device (200)} may correspond to {wireless device (100x), base station (200)} and / or {wireless device (100x), wireless device (100x)} of FIG. 18.

[0295] The first wireless device (100) includes one or more processors (102) and one or more memories (104), and may additionally include one or more transceivers (106) and / or one or more antennas (108). The processor (102) controls the memory (104) and / or transceivers (106) and may be configured to implement the descriptions, functions, procedures, proposals, methods and / or flowcharts of operation disclosed in this document. For example, the processor (102) may process information within the memory (104) to generate a first information / signal and then transmit a wireless signal containing the first information / signal through the transceiver (106). Additionally, the processor (102) may receive a wireless signal containing a second information / signal through the transceiver (106) and then store information obtained from the signal processing of the second information / signal in the memory (104). The memory (104) may be connected to the processor (102) and may store various information related to the operation of the processor (102). For example, the memory (104) may store software code containing instructions for performing some or all of the processes controlled by the processor (102) or for performing the descriptions, functions, procedures, proposals, methods, and / or operation sequence diagrams disclosed in this document. Here, the processor (102) and the memory (104) may be part of a communication modem / circuit / chipset designed to implement wireless communication technology (e.g., LTE, NR). The transceiver (106) may be connected to the processor (102) and may transmit and / or receive wireless signals through one or more antennas (108). The transceiver (106) may include a transmitter and / or receiver. The transceiver (106) may be combined with an RF (Radio Frequency) unit. In the present invention, the wireless device may refer to a communication modem / circuit / chipset.

[0296] Specifically, the first wireless device (100) or the first terminal may include a processor (102) connected to the RF transceiver and a memory (104). The memory (104) may include at least one program capable of performing operations related to the embodiments described in FIGS. 15 to 17.

[0297] The processor (102) arbitrarily selects a value of a back-off counter within a contention window associated with an unlicensed band and controls a transceiver (106) to transmit a first signal in the unlicensed band based on the back-off counter, and based on the fact that the first signal is a sidelink signal with HARQ (Hybrid Automatic Repeat and request) feedback enabled, the size of the contention window may be updated based on a feedback signal including an ACK (Acknowledgement) among the feedback signals for the first signal received from a plurality of terminals. Additionally, the processor (102) may perform the operations described in FIGS. 15 to 17 based on a program contained in memory (104).

[0298] Alternatively, a chipset comprising a processor (102) and a memory (104) may be configured. In this case, the chipset comprises at least one processor and at least one memory operably connected to the at least one processor and, when executed, causes the at least one processor to perform an operation, the operation comprising arbitrarily selecting a value of a back-off counter within a contention window related to an unlicensed band and controlling the RF transceiver to transmit a first signal in the unlicensed band based on the back-off counter, and based on the first signal being a sidelink signal with HARQ (Hybrid Automatic Repeat and request) feedback enabled, the size of the contention window may be updated based on a feedback signal including an ACK (Acknowledgement) among the feedback signals for the first signal received from a plurality of terminals. Additionally, the operation may perform the operations described in FIGS. 15 to 17 based on a program contained in the memory (104).

[0299] Alternatively, a computer-readable storage medium is provided that includes at least one computer program that causes the at least one processor to perform an operation, wherein the operation includes randomly selecting a value of a back-off counter within a contention window associated with an unlicensed band and controlling the RF transceiver to transmit a first signal in the unlicensed band based on the back-off counter, and wherein the first signal is a sidelink signal with HARQ (Hybrid Automatic Repeat and request) feedback enabled, the size of the contention window may be updated based on a feedback signal including an ACK (Acknowledgement) among feedback signals for the first signal received from a plurality of terminals.

[0300] The second wireless device (200) includes one or more processors (202) and one or more memories (204), and may additionally include one or more transceivers (206) and / or one or more antennas (208). The processor (202) controls the memory (204) and / or transceivers (206) and may be configured to implement the descriptions, functions, procedures, proposals, methods and / or operation sequences disclosed in this document. For example, the processor (202) may process information within the memory (204) to generate a third information / signal and then transmit a wireless signal containing the third information / signal through the transceiver (206). Additionally, the processor (202) may receive a wireless signal containing a fourth information / signal through the transceiver (206) and then store information obtained from the signal processing of the fourth information / signal in the memory (204). The memory (204) may be connected to the processor (202) and may store various information related to the operation of the processor (202). For example, the memory (204) may store software code containing instructions for performing some or all of the processes controlled by the processor (202) or for performing the descriptions, functions, procedures, proposals, methods, and / or operation sequences disclosed in this document. Here, the processor (202) and the memory (204) may be part of a communication modem / circuit / chip designed to implement wireless communication technology (e.g., LTE, NR). The transceiver (206) may be connected to the processor (202) and may transmit and / or receive wireless signals through one or more antennas (208). The transceiver (206) may include a transmitter and / or receiver. The transceiver (206) may be interchangeable with an RF unit. In the present invention, the wireless device may refer to a communication modem / circuit / chip.

[0301] Hereinafter, hardware elements of the wireless device (100, 200) will be described in more detail. Although not limited thereto, one or more protocol layers may be implemented by one or more processors (102, 202). For example, one or more processors (102, 202) may implement one or more layers (e.g., functional layers such as PHY, MAC, RLC, PDCP, RRC, SDAP). One or more processors (102, 202) may generate one or more Protocol Data Units (PDUs) and / or Service Data Units (SDUs) according to the descriptions, functions, procedures, proposals, methods, and / or flowcharts of operation disclosed in this document. One or more processors (102, 202) may generate messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or flowcharts of operation disclosed in this document. One or more processors (102, 202) may generate a signal (e.g., baseband signal) containing a PDU, SDU, message, control information, data, or information according to the functions, procedures, proposals, and / or methods disclosed in this document and provide it to one or more transceivers (106, 206). One or more processors (102, 202) may receive a signal (e.g., baseband signal) from one or more transceivers (106, 206) and may obtain a PDU, SDU, message, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or flowcharts disclosed in this document.

[0302] One or more processors (102, 202) may be referred to as a controller, microcontroller, microprocessor, or microcomputer. One or more processors (102, 202) may be implemented by hardware, firmware, software, or a combination thereof. For example, one or more Application Specific Integrated Circuits (ASICs), one or more Digital Signal Processors (DSPs), one or more Digital Signal Processing Devices (DSPDs), one or more Programmable Logic Devices (PLDs), or one or more Field Programmable Gate Arrays (FPGAs) may be included in one or more processors (102, 202). The descriptions, functions, procedures, proposals, methods, and / or flowcharts disclosed in this document may be implemented using firmware or software, and the firmware or software may be implemented to include modules, procedures, functions, etc. Firmware or software configured to perform the descriptions, functions, procedures, proposals, methods, and / or operation sequences disclosed in this document may be contained in one or more processors (102, 202) or stored in one or more memories (104, 204) and driven by one or more processors (102, 202). The descriptions, functions, procedures, proposals, methods, and / or operation sequences disclosed in this document may be implemented using firmware or software in the form of code, instructions, and / or sets of instructions.

[0303] One or more memories (104, 204) may be connected to one or more processors (102, 202) and may store various forms of data, signals, messages, information, programs, code, instructions, and / or commands. One or more memories (104, 204) may be composed of ROM, RAM, EPROM, flash memory, hard drive, registers, cache memory, computer read storage media, and / or combinations thereof. One or more memories (104, 204) may be located inside and / or outside of one or more processors (102, 202). Additionally, one or more memories (104, 204) may be connected to one or more processors (102, 202) through various technologies such as wired or wireless connections.

[0304] One or more transceivers (106, 206) may transmit user data, control information, wireless signals / channels, etc., as mentioned in the methods and / or operation flowcharts, etc., of this document to one or more other devices. One or more transceivers (106, 206) may receive user data, control information, wireless signals / channels, etc., as mentioned in the descriptions, functions, procedures, proposals, methods and / or operation flowcharts, etc., disclosed in this document from one or more other devices. For example, one or more transceivers (106, 206) may be connected to one or more processors (102, 202) and may transmit and receive wireless signals. For example, one or more processors (102, 202) may control one or more transceivers (106, 206) to transmit user data, control information, or wireless signals to one or more other devices. Additionally, one or more processors (102, 202) may control one or more transceivers (106, 206) to receive user data, control information, or wireless signals from one or more other devices. Additionally, one or more transceivers (106, 206) may be connected to one or more antennas (108, 208), and one or more transceivers (106, 206) may be configured to transmit and receive user data, control information, wireless signals / channels, etc., as described in the descriptions, functions, procedures, proposals, methods, and / or flowcharts of operation disclosed in this document through one or more antennas (108, 208). In this document, one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). One or more transceivers (106, 206) can convert the received wireless signal / channel, etc. from an RF band signal to a baseband signal in order to process the received user data, control information, wireless signal / channel, etc. using one or more processors (102, 202).One or more transceivers (106, 206) can convert user data, control information, wireless signals / channels, etc. processed using one or more processors (102, 202) from baseband signals to RF band signals. To this end, one or more transceivers (106, 206) may include (analog) oscillators and / or filters.

[0305] Examples of wireless device applications to which the present invention is applied

[0306] FIG. 20 illustrates another example of a wireless device to which the present invention applies. The wireless device may be implemented in various forms depending on the use-example / service (see FIG. 21).

[0307] Referring to FIG. 20, the wireless device (100, 200) corresponds to the wireless device (100, 200) of FIG. 19 and may be composed of various elements, components, units / parts, and / or modules. For example, the wireless device (100, 200) may include a communication unit (110), a control unit (120), a memory unit (130), and additional elements (140). The communication unit may include a communication circuit (112) and transceiver(s) (114). For example, the communication circuit (112) may include one or more processors (102, 202) and / or one or more memories (104, 204) of FIG. 19. For example, the transceiver(s) (114) may include one or more transceivers (106, 206) and / or one or more antennas (108, 208) of FIG. 19. The control unit (120) is electrically connected to the communication unit (110), the memory unit (130), and additional elements (140) and controls the general operation of the wireless device. For example, the control unit (120) may control the electrical / mechanical operation of the wireless device based on a program / code / command / information stored in the memory unit (130). Additionally, the control unit (120) may transmit information stored in the memory unit (130) to an external (e.g., another communication device) via a wireless / wired interface through the communication unit (110), or store information received from an external (e.g., another communication device) via a wireless / wired interface through the communication unit (110) in the memory unit (130).

[0308] The additional element (140) can be configured in various ways depending on the type of wireless device. For example, the additional element (140) may include at least one of a power unit / battery, an input / output unit (I / O unit), a driving unit, and a computing unit. Although not limited thereto, the wireless device may be implemented in the form of a robot (Fig. 18, 100a), a vehicle (Fig. 18, 100b-1, 100b-2), an XR device (Fig. 18, 100c), a portable device (Fig. 18, 100d), a home appliance (Fig. 18, 100e), an IoT device (Fig. 18, 100f), a digital broadcasting terminal, a hologram device, a public safety device, an MTC device, a medical device, a fintech device (or financial device), a security device, a climate / environment device, an AI server / device (Fig. 18, 400), a base station (Fig. 18, 200), a network node, etc. Wireless devices can be used in a movable or fixed location depending on the use—e.g., service.

[0309] In FIG. 20, various elements, components, units / parts, and / or modules within the wireless device (100, 200) may be entirely interconnected via a wired interface, or at least a portion may be wirelessly connected via a communication unit (110). For example, within the wireless device (100, 200), the control unit (120) and the communication unit (110) may be wired, and the control unit (120) and the first unit (e.g., 130, 140) may be wirelessly connected via the communication unit (110). Additionally, each element, component, unit / part, and / or module within the wireless device (100, 200) may include one or more additional elements. For example, the control unit (120) may be composed of one or more sets of processors. For example, the control unit (120) may be composed of a set of a communication control processor, an application processor, an Electronic Control Unit (ECU), a graphics processing processor, a memory control processor, etc. As another example, the memory unit (130) may be composed of RAM (Random Access Memory), DRAM (Dynamic RAM), ROM (Read Only Memory), flash memory, volatile memory, non-volatile memory and / or a combination thereof.

[0310] Examples of vehicles or autonomous vehicles to which the present invention is applied

[0311] FIG. 21 illustrates a vehicle or autonomous vehicle to which the present invention applies. The vehicle or autonomous vehicle may be implemented as a mobile robot, a vehicle, a train, an aerial vehicle (AV), a ship, etc.

[0312] Referring to FIG. 21, a vehicle or autonomous vehicle (100) may include an antenna unit (108), a communication unit (110), a control unit (120), a driving unit (140a), a power supply unit (140b), a sensor unit (140c), and an autonomous driving unit (140d). The antenna unit (108) may be configured as part of the communication unit (110). Blocks 110 / 130 / 140a to 140d each correspond to blocks 110 / 130 / 140 of FIG. 20.

[0313] The communication unit (110) can transmit and receive signals (e.g., data, control signals, etc.) with external devices such as other vehicles, base stations (e.g., base stations, roadside base stations (Roadside units), etc.), and servers. The control unit (120) can perform various operations by controlling elements of the vehicle or autonomous vehicle (100). The control unit (120) may include an Electronic Control Unit (ECU). The driving unit (140a) can drive the vehicle or autonomous vehicle (100) on the ground. The driving unit (140a) may include an engine, motor, power train, wheels, brakes, steering device, etc. The power supply unit (140b) supplies power to the vehicle or autonomous vehicle (100) and may include wired / wireless charging circuits, batteries, etc. The sensor unit (140c) can obtain vehicle status, surrounding environment information, user information, etc. The sensor unit (140c) may include an IMU (inertial measurement unit) sensor, a collision sensor, a wheel sensor, a speed sensor, an inclination sensor, a weight detection sensor, a heading sensor, a position module, a vehicle forward / reverse sensor, a battery sensor, a fuel sensor, a tire sensor, a steering sensor, a temperature sensor, a humidity sensor, an ultrasonic sensor, an illuminance sensor, a pedal position sensor, etc. The autonomous driving unit (140d) may implement technologies such as maintaining the driving lane, technologies for automatically adjusting speed such as adaptive cruise control, technologies for automatically driving along a predetermined path, and technologies for automatically setting a path and driving when a destination is set.

[0314] For example, the communication unit (110) can receive map data, traffic information data, etc. from an external server. The autonomous driving unit (140d) can generate an autonomous driving path and a driving plan based on the acquired data. The control unit (120) can control the drive unit (140a) so that the vehicle or the autonomous vehicle (100) moves along the autonomous driving path according to the driving plan (e.g., speed / direction control). During autonomous driving, the communication unit (110) can acquire the latest traffic information data from an external server non-periodically and can acquire surrounding traffic information data from surrounding vehicles. Additionally, during autonomous driving, the sensor unit (140c) can acquire vehicle status and surrounding environment information. The autonomous driving unit (140d) can update the autonomous driving path and the driving plan based on the newly acquired data / information. The communication unit (110) can transmit information regarding the vehicle location, autonomous driving path, driving plan, etc. to an external server. An external server can predict traffic information data in advance using AI technology, etc., based on information collected from vehicles or autonomous vehicles, and can provide the predicted traffic information data to vehicles or autonomous vehicles.

[0315] Here, the wireless communication technology implemented in the wireless device (XXX, YYY) of this specification may include LTE, NR, and 6G, as well as Narrowband Internet of Things for low-power communication. For example, NB-IoT technology may be an example of LPWAN (Low Power Wide Area Network) technology and may be implemented according to standards such as LTE Cat NB1 and / or LTE Cat NB2, but is not limited to the names mentioned above. Additionally, or generally, the wireless communication technology implemented in the wireless device (XXX, YYY) of this specification may perform communication based on LTE-M technology. For example, LTE-M technology may be an example of LPWAN technology and may be referred to by various names such as eMTC (enhanced Machine Type Communication). For example, LTE-M technology may be implemented in at least one of various standards such as 1) LTE CAT 0, 2) LTE Cat M1, 3) LTE Cat M2, 4) LTE non-BL (non-Bandwidth Limited), 5) LTE-MTC, 6) LTE Machine Type Communication, and / or 7) LTE M, and is not limited to the names mentioned above. Additionally or generally, wireless communication technology implemented in the wireless device (XXX, YYY) of this specification may include at least one of ZigBee, Bluetooth, and Low Power Wide Area Network (LPWAN) with consideration for low-power communication, and is not limited to the names mentioned above. As an example, ZigBee technology can create personal area networks (PANs) related to small / low-power digital communication based on various standards such as IEEE 802.15.4, and may be referred to by various names.

[0316] The embodiments described above are combinations of the components and features of the present invention in a specific form. Each component or feature should be considered optional unless otherwise explicitly stated. Each component or feature may be implemented in a form not combined with other components or features. Additionally, it is possible to construct embodiments of the present invention by combining some components and / or features. The order of operations described in the embodiments of the present invention may be changed. Some components or features of one embodiment may be included in another embodiment, or may be replaced with corresponding components or features of another embodiment. It is obvious that embodiments may be constructed by combining claims that do not have an explicit citation relationship in the claims, or that new claims may be included by amendment after filing.

[0317] In this document, embodiments of the present invention are described primarily with a focus on the signal transmission and reception relationship between a terminal and a base station. This transmission and reception relationship is extended in the same or similar manner to signal transmission and reception between a terminal and a relay or between a base station and a relay. Specific operations described in this document as being performed by a base station may, in some cases, be performed by an upper node. That is, it is self-evident that various operations performed for communication with a terminal in a network consisting of multiple network nodes including a base station may be performed by the base station or other network nodes other than the base station. The base station may be replaced by terms such as fixed station, Node B, eNode B (eNB), and access point. Additionally, the terminal may be replaced by terms such as User Equipment (UE), Mobile Station (MS), and Mobile Subscriber Station (MSS).

[0318] Embodiments according to the present invention may be implemented by various means, for example, hardware, firmware, software, or a combination thereof. In the case of implementation by hardware, one embodiment of the present invention may be implemented by one or more ASICs (application specific integrated circuits), DSPs (digital signal processors), DSPDs (digital signal processing devices), PLDs (programmable logic devices), FPGAs (field programmable gate arrays), processors, controllers, microcontrollers, microprocessors, etc.

[0319] In the case of implementation by firmware or software, an embodiment of the present invention may be implemented in the form of a module, procedure, function, etc., that performs the functions or operations described above. Software code may be stored in a memory unit and executed by a processor. The memory unit may be located inside or outside the processor and may exchange data with the processor by various means already known.

[0320] It is obvious to those skilled in the art that the present invention may be embodied in other specific forms without departing from the features of the invention. Accordingly, the foregoing detailed description should not be interpreted restrictively in all respects but should be considered exemplary. The scope of the invention shall be determined by a reasonable interpretation of the appended claims, and all modifications within the equivalent scope of the invention are included within the scope of the invention.

Claims

Claim 1 A method by a first terminal comprising: a step of setting a counter value based on a random number uniformly distributed between 0 and a contention window value; a step of transmitting at least one signal for direct communication between terminals based on the counter value; and a step of adjusting the contention window value, wherein, based on the fact that HARQ (Hybrid Automatic Repeat request) feedback for the at least one signal is disabled, the contention window value is updated based on the number of retransmissions of the same Transport Block (TB) associated with the at least one signal. Claim 2 A method according to claim 1, characterized in that, based on the fact that the number of retransmissions of the TB is smaller than a predefined threshold, the contention window value is adjusted to a minimum contention window value. Claim 3 A method according to claim 1, characterized in that, based on the fact that the number of retransmissions of the TB is greater than a predefined threshold value, the contention window value is adjusted to increase by a preconfigured allowable value. Claim 4 delete Claim 5 delete Claim 6 delete Claim 7 delete Claim 8 delete Claim 9 A method according to claim 1, wherein, based on the fact that the at least one signal is a signal requesting a CSI (Channel State Information) report, the contention window value is initialized to an initial value when the CSI report corresponding to the at least one signal is received. Claim 10 A method according to claim 1, further comprising the step of selecting a transmission resource for transmitting at least one signal, wherein the transmission resource is re-selected based on the fact that the transmission resource precedes the expiration time of a counter based on the counter value. Claim 11 A method according to claim 1, wherein the at least one signal is a data channel for direct communication between terminals scheduled by a control channel for direct communication between terminals that includes instruction information for deactivating HARQ feedback for direct communication between terminals. Claim 12 A first terminal comprises: a Radio Frequency (RF) transceiver; and a processor connected to the RF transceiver; wherein the processor sets a counter value based on a random number uniformly distributed between 0 and a contention window value, transmits at least one signal for direct communication between terminals based on the counter value, adjusts the contention window value, and, based on the fact that Hybrid Automatic Repeat request (HARQ) feedback for the at least one signal is disabled, the contention window value is updated based on the number of retransmissions of the same Transport Block (TB) associated with the at least one signal. Claim 13 delete Claim 14 A chipset comprising: at least one processor; and at least one memory operably connected to the at least one processor and, when executed, causing the at least one processor to perform an operation, wherein the operation includes: setting a counter value based on a random number uniformly distributed between 0 and a contention window value, transmitting at least one signal for direct communication between terminals based on the counter value, and adjusting the contention window value, wherein the contention window value is updated based on the number of retransmissions of the same Transport Block (TB) associated with the at least one signal, based on the fact that the signal for direct communication between terminals has HARQ (Hybrid Automatic Repeat request) feedback for the at least one signal disabled. Claim 15 A non-transient computer-readable storage medium recording instructions for performing the method described in paragraph 1.

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