Method and apparatus for carrier selection

Abstract

A method by which a first device performs wireless communication, and an apparatus supporting same are provided. The method may comprise the steps of: acquiring configuration information related to a first carrier; and acquiring information related to channel congestion of the first carrier. For example, whether to include the first carrier in candidate carriers can be based on the channel congestion of the first carrier and the value of a discontinuous transmission (DTX) counter related to the first carrier.

Description

Method and device for carrier selection

[0001] The present disclosure relates to a wireless communication system.

[0002] 5G NR, the successor to LTE (long-term evolution), is a new clean-slate mobile communications system characterized by high performance, low latency, and high availability. 5G NR can utilize all available spectrum resources, from low-frequency bands below 1 GHz, mid-frequency bands between 1 GHz and 10 GHz, and high-frequency (millimeter wave) bands above 24 GHz.

[0003] The 6G (wireless communication) system aims to achieve (i) very high data rates per device, (ii) a very large number of connected devices, (iii) global connectivity, (iv) very low latency, (v) low energy consumption for battery-free Internet of Things (IoT) devices, (vi) ultra-reliable connectivity, and (vii) connected intelligence with machine learning capabilities. The vision of the 6G system can be divided into four aspects: intelligent connectivity, deep connectivity, holographic connectivity, and ubiquitous connectivity, and the 6G system can satisfy the requirements as shown in Table 1 below. For example, Table 1 can represent an example of the requirements of a 6G system.

[0004] Per device peak data rate 1 Tbps E2E latency 1 ms Maximum spectral efficiency 100 bps / Hz Mobility support Up to 1000 km / hr Satellite integration Fully AI Fully autonomous vehicle Fully XR Fully haptic communication Fully

[0005] In one embodiment, a method for a first device to perform wireless communication is provided. The method may include the steps of: obtaining configuration information related to a first carrier; and obtaining information related to channel congestion of the first carrier. For example, whether to include the first carrier in a candidate carrier may be determined based on the channel congestion of the first carrier and the value of a discontinuous transmission (DTX) counter related to the first carrier.

[0006] In one embodiment, a first device configured to perform wireless communication is provided. The first device may include at least one transceiver; at least one processor; and at least one memory coupled to the at least one processor and storing instructions. For example, the instructions, when executed by the at least one processor, may cause the first device to: obtain configuration information related to a first carrier; and obtain information related to channel congestion of the first carrier. For example, whether to include the first carrier in a candidate carrier may be determined based on the channel congestion of the first carrier and the value of a discontinuous transmission (DTX) counter related to the first carrier.

[0007] In one embodiment, a processing device configured to control a first device is provided. The processing device includes at least one processor; and at least one memory coupled to the at least one processor and storing instructions, wherein the instructions, when executed by the at least one processor, cause the first device to: obtain configuration information related to a first carrier; and obtain information related to channel congestion of the first carrier. For example, whether to include the first carrier in a candidate carrier may be based on the channel congestion of the first carrier and the value of a discontinuous transmission (DTX) counter related to the first carrier.

[0008] In one embodiment, a non-transitory computer-readable storage medium having instructions recorded thereon is provided. The instructions, when executed, may cause a first device to: obtain configuration information related to a first carrier; and obtain information related to channel congestion of the first carrier. For example, whether to include the first carrier in a candidate carrier may be based on the channel congestion of the first carrier and the value of a discontinuous transmission (DTX) counter related to the first carrier.

[0009] Figure 1 illustrates a device-to-device communication procedure according to one embodiment of the present disclosure.

[0010] FIG. 2 illustrates a radio protocol architecture according to one embodiment of the present disclosure.

[0011] FIG. 3 illustrates the structure of a wireless frame according to one embodiment of the present disclosure.

[0012] FIG. 4 illustrates a slot structure of a frame according to one embodiment of the present disclosure.

[0013] FIG. 5 illustrates an example of a BWP according to one embodiment of the present disclosure.

[0014] FIG. 6 illustrates a procedure for a terminal to perform V2X or SL communication according to a resource allocation mode, according to one embodiment of the present disclosure.

[0015] FIG. 7 illustrates a communication structure that can be provided in a 6G system according to one embodiment of the present disclosure.

[0016] FIG. 8 illustrates an example of a communication scenario based on a 6G system according to an embodiment of the present disclosure.

[0017] FIG. 9 illustrates an example of a sensing operation according to one embodiment of the present disclosure.

[0018] FIG. 10 illustrates a carrier (re)selection method according to one embodiment of the present disclosure.

[0019] FIG. 11 illustrates a carrier (re)selection method according to one embodiment of the present disclosure.

[0020] FIG. 12 illustrates a method for a first device to perform wireless communication according to one embodiment of the present disclosure.

[0021] FIG. 13 illustrates a method for a second device to perform wireless communication according to one embodiment of the present disclosure.

[0022] Fig. 14 illustrates a communication system (1) according to one embodiment of the present disclosure.

[0023] FIG. 15 illustrates a wireless device according to an embodiment of the present disclosure.

[0024] FIG. 16 illustrates a signal processing circuit for a transmission signal according to one embodiment of the present disclosure.

[0025] FIG. 17 illustrates a wireless device according to one embodiment of the present disclosure.

[0026] FIG. 18 illustrates a mobile device according to one embodiment of the present disclosure.

[0027] FIG. 19 illustrates a vehicle or autonomous vehicle according to one embodiment of the present disclosure.

[0028] In this disclosure, "A or B" can mean "only A," "only B," or "both A and B." In other words, "A or B" in this disclosure can be interpreted as "A and / or B." For example, "A, B or C" in this disclosure can mean "only A," "only B," "only C," or "any combination of A, B and C."

[0029] As used herein, a slash ( / ) or a comma may mean "and / or." For example, "A / B" may mean "A and / or B." Accordingly, "A / B" may mean "only A," "only B," or "both A and B." For example, "A, B, C" may mean "A, B, or C."

[0030] In the present disclosure, “at least one of A and B” may mean “only A,” “only B,” or “both A and B.” Additionally, in the present disclosure, the expressions “at least one of A or B” or “at least one of A and / or B” may be interpreted identically to “at least one of A and B.”

[0031] Additionally, in the present disclosure, “at least one of A, B and C” can mean “only A,” “only B,” “only C,” or “any combination of A, B and C.” Additionally, “at least one of A, B or C” or “at least one of A, B and / or C” can mean “at least one of A, B and C.”

[0032] Additionally, parentheses used in the present disclosure may mean "for example." Specifically, when indicated as "control information (PDCCH)", "PDCCH" may be proposed as an example of "control information." In other words, "control information" in the present disclosure is not limited to "PDCCH," and "PDCCH" may be proposed as an example of "control information." Furthermore, even when indicated as "control information (i.e., PDCCH)", "PDCCH" may be proposed as an example of "control information."

[0033] In the following explanation, ‘when, if, in case of’ can be replaced with ‘based on’.

[0034] Technical features individually described in one drawing in this disclosure may be implemented individually or simultaneously.

[0035] In the present disclosure, higher layer parameters may be parameters set for the terminal, preset, or predefined. For example, a base station or network may transmit higher layer parameters to the terminal. For example, the higher layer parameters may be transmitted via radio resource control (RRC) signaling or medium access control (MAC) signaling.

[0036] In the present disclosure, "setting or defining" may be interpreted as being set or preset to a device through predefined signaling (e.g., SIB, MAC, RRC) from a base station or a network. In the present disclosure, "setting or defining" may be interpreted as being preset to a device. In the present disclosure, "setting or defining" may be interpreted as being set or preset to a device through predefined signaling (e.g., MAC, RRC, SCI (sidelink control information), device-to-device signaling control information, etc.) from another device. In the present disclosure, "setting or defining" may be interpreted as being preset to a device.

[0037] In the present disclosure, a user equipment (UE) may refer to a device, a portable device, a wireless device, etc. In the present disclosure, a base station (BS) may refer to a radio access network (RAN) node, a non-terrestrial network (NTN) cell / node, a transmission reception point (TRP), a network, an integrated access and backhaul (IAB) node, a device, a portable device, a wireless device, etc.

[0038] The technology proposed in the present disclosure 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 with wireless technologies such as UTRA (universal terrestrial radio access) or CDMA2000. TDMA can be implemented with wireless technologies such as GSM (global system for mobile communications) / GPRS (general packet radio service) / EDGE (enhanced data rates for GSM evolution). OFDMA can be implemented with wireless technologies such as IEEE (Institute of Electrical and Electronics Engineers) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, E-UTRA (evolved UTRA), LTE (long term evolution), and 5G NR.

[0039] The technology proposed in this disclosure can be implemented with 6G wireless technology and applied to various 6G systems. For example, 6G systems can have key factors such as enhanced mobile broadband (eMBB), ultra-reliable low latency communications (URLLC), massive machine-type communication (mMTC), artificial intelligence (AI) integrated communication, tactile internet, high throughput, high network capacity, high energy efficiency, low backhaul and access network congestion, and enhanced data security.

[0040] FIG. 1 illustrates a device-to-device communication procedure according to one embodiment of the present disclosure. The embodiment of FIG. 1 may be combined with various embodiments of the present disclosure, and some descriptions, functions, procedures, proposals, methods, and / or operations of the embodiments may be omitted.

[0041] Referring to FIG. 1, in step S101, a first device and a second device can perform synchronization. For example, the first device can be a terminal and / or at least one of the devices proposed in the present disclosure. For example, the second device can be a base station, a network, a RAN node, an NTN node / cell, a TRP, a terminal and / or at least one of the devices proposed in the present disclosure. For example, the first device can perform an initial cell search operation. For example, the first device can detect at least one synchronization signal transmitted by the second device according to a predefined rule. Here, for example, the synchronization signal can include a plurality of synchronization signals classified according to a structure or purpose (e.g., a primary synchronization signal, a secondary synchronization signal, etc.). Through this, the first device can identify the boundaries of the frame, subframe, time unit, slot, and / or symbol of the second device, and the first device can obtain information about the second device (e.g., a cell identifier).

[0042] In step S103, the first device can obtain system information transmitted by the second device. For example, the system information may include information related to the properties, characteristics, and / or capabilities of the second device required to connect to the second device and use the service. For example, the system information may be classified according to content (e.g., whether it is essential for connection), transmission structure (e.g., the channel used, whether it is provided on-demand), etc. For example, the system information may be classified into a master information block (MIB) and a system information block (SIB). For example, if necessary, the first device may transmit a signal requesting system information before receiving the system information. For example, the request and provision of system information may be performed after a random access procedure described below.

[0043] In step S105, the first device and the second device can perform a random access procedure. For example, the first device can transmit and / or receive at least one message (e.g., a random access preamble, a random access response message, etc.) for the random access procedure based on information related to a random access channel of the second device obtained through system information (e.g., channel location, channel structure, structure of supported preamble, etc.). For example, the first device can transmit a preamble (e.g., Msg1) through the random access channel, the first device can receive a random access response message (e.g., Msg2), the first device can transmit a message (e.g., Msg3) including information related to the first device (e.g., identification information) to the second device using scheduling information included in the random access response message, and the first device can receive a message (e.g., Msg4) for contention resolution and / or connection establishment. For example, Msg1 and Msg3 can be sent and received as one message (e.g., MsgA), and / or Msg2 and Msg4 can be sent and received as one message (e.g., MsgB).

[0044] In step S107, the first device and the second device may perform signaling of control information. Here, for example, the control information may be defined in various layers, such as a layer that controls a connection (e.g., a radio resource control (RRC) layer), a layer that handles mapping between logical channels and transport channels (e.g., a media access control (MAC) layer), a layer that handles physical channels (e.g., a physical (PHY) layer), etc. For example, the first device and the second device may perform at least one of signaling for establishing a connection, signaling for determining settings related to communication, and / or signaling for indicating allocated resources. For example, the control information may be signaled / transmitted via a control channel. For example, the control information and / or the control channel may be used to schedule at least one of data, a data channel (e.g., a shared channel), and / or control information on the data channel.

[0045] In step S109, the first device and the second device may transmit and / or receive data. For example, the first device and the second device may process, transmit, and / or receive data based on signaling of control information. For example, when transmitting data, the first device or the second device may perform at least one of channel encoding, rate matching, scrambling, constellation mapping, layer mapping, waveform modulation, antenna mapping, and / or resource mapping on the information bits. For example, when receiving data, the first device or the second device may perform at least one of signal extraction from resources, waveform demodulation for each antenna, signal arrangement considering layer mapping, constellation demapping, descrambling, and / or channel decoding.

[0046] For example, the layers of a radio interface protocol between a first device and a second device can be divided into L1 (layer 1), L2 (layer 2), L3 (layer 3), etc. For example, a physical layer belonging to the first layer can provide an information transfer service using a physical channel, and an RRC (radio resource control) layer located in the third layer can play a role in controlling radio resources between the first device and the second device. For this purpose, for example, the RRC layer can exchange RRC messages between the first device and the second device.

[0047] FIG. 2 illustrates a radio protocol architecture according to an embodiment of the present disclosure. The embodiment of FIG. 2 may be combined with various embodiments of the present disclosure, and some descriptions, functions, procedures, proposals, methods, and / or operations of the embodiments may be omitted. For example, (a) of FIG. 2 may illustrate a radio protocol stack of a user plane for uplink communication or downlink communication, and (b) of FIG. 2 may illustrate a radio protocol stack of a control plane for uplink communication or downlink communication. For example, (c) of FIG. 2 may illustrate a radio protocol stack of a user plane for device-to-device communication, and (d) of FIG. 2 may illustrate a radio protocol stack of a control plane for device-to-device communication.

[0048] For example, the physical layer can provide information transmission services to upper layers using physical channels. For example, the physical layer can be connected to the upper layer, the medium access control (MAC) layer, through a transport channel. For example, data can be transmitted between the MAC layer and the physical layer through the transport channel. For example, transport channels can be classified according to how and with what characteristics data is transmitted over the wireless interface. For example, data can be transmitted between different physical layers (e.g., between the physical layers of a first device and a second device) through a physical channel. For example, the physical channel can be modulated using an orthogonal frequency division multiplexing (OFDM) scheme, and time and frequency can be utilized as radio resources.

[0049] For example, the MAC layer can provide services to the upper layer, the radio link control (RLC) layer, through logical channels. For example, the MAC layer can provide a mapping function from multiple logical channels to multiple transport channels. For example, the MAC layer can provide a logical channel multiplexing function by mapping multiple logical channels to a single transport channel. For example, the MAC sublayer can provide data transmission services on logical channels.

[0050] For example, the RLC layer can perform concatenation, segmentation, and reassembly of RLC service data units (SDUs). For example, to guarantee the various quality of service (QoS) required by radio bearers (RBs), the RLC layer can provide three operating modes: transparent mode (TM), unacknowledged mode (UM), and acknowledged mode (AM). For example, AM RLC can provide error correction through automatic repeat request (ARQ).

[0051] For example, the RRC (radio resource control) layer can be defined only in the control plane. For example, the RRC layer can be responsible for controlling logical channels, transport channels, and physical channels in relation to the configuration, re-configuration, and release of radio bearers. For example, an RB can mean a logical path provided by a first layer (e.g., a physical layer) and a second layer (e.g., a MAC layer, an RLC layer, a PDCP (packet data convergence protocol) layer, a SDAP (service data adaptation protocol) layer, etc.) for data transmission between a first device and a second device.

[0052] For example, the functions of the PDCP layer in the user plane may include forwarding of user data, header compression, and ciphering. For example, the functions of the PDCP layer in the control plane may include forwarding of control plane data and ciphering / integrity protection.

[0053] For example, establishing an RB can refer to the process of defining the characteristics of the radio protocol layer and channel to provide a specific service, and setting specific parameters and operating methods for each. For example, RBs can be divided into two types: signaling radio bearers (SRBs) and data radio bearers (DRBs). For example, SRBs can be used as a channel to transmit RRC messages in the control plane, while DRBs can be used as a channel to transmit user data in the user plane.

[0054] For example, a downlink transmission channel may include at least one of a broadcast channel (BCH) for transmitting system information, and / or a downlink shared channel (SCH) for transmitting user traffic or control messages. For example, traffic or control messages of a downlink multicast or broadcast service may be transmitted through the downlink SCH, or may be transmitted through a separate downlink multicast channel (MCH). Meanwhile, an uplink transmission channel may include at least one of a random access channel (RACH) for transmitting initial control messages, and / or an uplink shared channel (SCH) for transmitting user traffic or control messages. For example, a logical channel located above a transmission channel and mapped to the transmission channel may include at least one of a broadcast control channel (BCCH), a paging control channel (PCCH), a common control channel (CCCH), a multicast control channel (MCCH), and / or a multicast traffic channel (MTCH).

[0055] FIG. 3 illustrates the structure of a wireless frame according to an embodiment of the present disclosure. The embodiment of FIG. 3 may be combined with various embodiments of the present disclosure, and some descriptions, functions, procedures, proposals, methods, and / or operations of the embodiments may be omitted.

[0056] Referring to FIG. 3, for example, a radio frame may be used in uplink transmission, downlink transmission, and / or device-to-device transmission. For example, a radio frame may have a length of 10 ms and may be defined as two 5 ms half-frames (HF). For example, a half-frame may include five 1 ms subframes (SF). For example, a subframe may be divided into one or more slots, and the number of slots within a subframe may be determined according to a subcarrier spacing (SCS). For example, each slot may include 12 or 14 OFDM (A) symbols, depending on a cyclic prefix (CP).

[0057] For example, when normal CP is used, each slot can contain 14 symbols. For example, when extended CP is used, each slot can contain 12 symbols. Here, for example, the symbols can contain OFDM symbols (or CP-OFDM symbols), SC-FDMA (single carrier-FDMA) symbols (or DFT-s-OFDM (Discrete Fourier Transform-spread-OFDM) symbols).

[0058] Table 2 below shows the number of symbols per slot (N) depending on the SCS setting (u) when normal CP or extended 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) is an example.

[0059] CP type SCS (15*2 u )N slot symb N frame,u slot N subframe,u slot Normal CP15kHz (u=0)1410130kHz (u=1)1420260kHz (u=2)14404120kHz (u=3)14808240kHz (u=4)1416016Extended CP60kHz (u=2)12404

[0060] For example, OFDM(A) numerology (e.g., SCS, CP length, etc.) may be set differently between multiple cells that are merged into a single terminal. Accordingly, the (absolute time) interval of time resources (e.g., subframes, slots, or transmit time intervals (TTIs)) composed of the same number of symbols may be set differently between the merged cells. For example, in the present disclosure, time resources such as subframes, slots, TTIs, etc. may be referred to as time units.

[0061] For example, multiple numerologies, or SCSs, may be supported to support various services. For example, a 15 kHz SCS may support wide areas in traditional cellular bands, while a 30 kHz / 60 kHz SCS may support dense urban areas, lower latency, and wider carrier bandwidth. For example, a 60 kHz or higher SCS may support bandwidths greater than 24.25 GHz to overcome phase noise.

[0062] FIG. 4 illustrates a slot structure of a frame according to an embodiment of the present disclosure. The embodiment of FIG. 4 may be combined with various embodiments of the present disclosure, and some descriptions, functions, procedures, proposals, methods, and / or operations of the embodiments may be omitted.

[0063] Referring to FIG. 4, for example, a slot may include multiple symbols in the time domain. For example, a carrier may include multiple subcarriers in the frequency domain. For example, a resource block (RB) may be defined as multiple consecutive subcarriers in the frequency domain. For example, a bandwidth part (BWP) may be defined as multiple consecutive (P)RBs ((physical) resource blocks) in the frequency domain, and may correspond to one numerology (e.g., SCS, CP length, etc.). For example, a carrier may include at most N BWPs (where N is a positive integer). For example, data communication may be performed through an activated BWP. For example, each element may be referred to as a resource element (RE) in the resource grid, and one complex symbol may be mapped to it.

[0064] For example, a BWP may be a contiguous set of PRBs in a given numerology. For example, a PRB may be selected from a contiguous subset of common resource blocks (CRBs) for a given numerology on a given carrier.

[0065] For example, the BWP may be at least one of an active BWP, an initial BWP, and / or a default BWP. For example, the UE may not monitor the downlink radio link quality in a DL BWP other than the active DL BWP on the PCell (primary cell). For example, the UE may not receive a physical downlink control channel (PDCCH), a physical downlink shared channel (PDSCH), or a channel state information-reference signal (CSI-RS) (except for radio resource management (RRM)) outside of the active DL BWP. For example, the UE may not trigger channel state information (CSI) reporting for an inactive DL BWP. For example, the UE may not transmit a physical uplink control channel (PUCCH) or a physical uplink shared channel (PUSCH) outside of the active UL BWP. For example, for downlink, the initial BWP can be given as a set of consecutive resource blocks (RBs) for the remaining minimum system information (RMSI) CORESET (control resource set) (set by the physical broadcast channel (PBCH)). For uplink, for example, the initial BWP can be given by the system information block (SIB) for the random access procedure. For example, the default BWP can be set by a higher layer. For example, the initial value of the default BWP can be the initial DL BWP.For energy saving, if a terminal does not detect DCI (downlink control information) for a certain period of time, the terminal may switch its active BWP to a default BWP.

[0066] FIG. 5 illustrates an example of a BWP according to an embodiment of the present disclosure. The embodiment of FIG. 5 may be combined with various embodiments of the present disclosure, and some descriptions, functions, procedures, proposals, methods, and / or operations of the embodiments may be omitted. In the embodiment of FIG. 5, it is assumed that there are three BWPs.

[0067] Referring to FIG. 5, for example, a common resource block (CRB) may be a carrier resource block numbered from one end of a carrier band to the other, and a PRB may be a numbered resource block within each BWP. For example, point A may indicate a common reference point for a resource block grid.

[0068] For example, BWP is point A, offset from point A (N start BWP ) and bandwidth (N size BWP ) can be set by. For example, point A can be an outer reference point of the PRB of a carrier where subcarrier 0 of all numerologies (e.g., all numerologies supported by the network on that carrier) aligns. For example, the offset can be the PRB spacing between the lowest subcarrier in a given numerology and point A. For example, the bandwidth can be the number of PRBs in a given numerology.

[0069] Meanwhile, in the present disclosure, the PSCCH may be replaced by a control channel, a physical control channel, a control channel associated with a sidelink, a physical control channel associated with a sidelink, etc. In the present disclosure, the PSSCH may be replaced by a shared channel, a physical shared channel, a shared channel associated with a sidelink, a physical shared channel associated with a sidelink, etc.

[0070] FIG. 6 illustrates a procedure for a terminal to perform V2X or SL communication according to a resource allocation mode, according to an embodiment of the present disclosure. The embodiment of FIG. 6 may be combined with various embodiments of the present disclosure, and some descriptions, functions, procedures, proposals, methods, and / or operations of the embodiments may be omitted.

[0071] Referring to (a) of FIG. 6, in resource allocation mode 1, the base station may schedule SL resources to be used by the terminal for SL transmission. For example, in step S600, the base station may transmit information related to SL resources and / or information related to UL resources to the first terminal. For example, the UL resources may include PUCCH resources and / or PUSCH resources. For example, the UL resources may be resources for reporting SL HARQ feedback to the base station.

[0072] For example, a first terminal may receive information related to a dynamic grant (DG) resource and / or information related to a configured grant (CG) resource from a base station. For example, a CG resource may include a CG type 1 resource or a CG type 2 resource. In this specification, a DG resource may be a resource that a base station configures / allocates to the first terminal via downlink control information (DCI). In this specification, a CG resource may be a (periodic) resource that a base station configures / allocates to the first terminal via DCI and / or an RRC message. For example, in the case of a CG type 1 resource, the base station may transmit an RRC message including information related to the CG resource to the first terminal. For example, in the case of a CG type 2 resource, the base station may transmit an RRC message including information related to the CG resource to the first terminal, and the base station may transmit a DCI related to activation or release of the CG resource to the first terminal.

[0073] In step S610, the first terminal may transmit a PSCCH (e.g., Sidelink Control Information (SCI) or 1st-stage SCI) to the second terminal based on the resource scheduling. In step S620, the first terminal may transmit a PSSCH (e.g., 2nd-stage SCI, MAC PDU, data, etc.) related to the PSCCH to the second terminal. In step S630, the first terminal may receive a PSFCH related to the PSCCH / PSSCH from the second terminal. For example, HARQ feedback information (e.g., NACK information or ACK information) may be received from the second terminal via the PSFCH. In step S640, the first terminal may transmit / report HARQ feedback information to the base station via a PUCCH or a PUSCH. For example, the HARQ feedback information reported to the base station may be information generated by the first terminal based on the HARQ feedback information received from the second terminal. For example, the HARQ feedback information reported to the base station may be information generated by the first terminal based on a rule set in advance. For example, the DCI may be DCI for scheduling SL.

[0074] Referring to (b) of FIG. 6, in resource allocation mode 2, the terminal can determine SL transmission resources within SL resources set by the base station / network or preset SL resources. For example, the set SL resources or preset SL resources may be a resource pool. For example, the terminal can autonomously select or schedule resources for SL transmission. For example, the terminal can perform SL communication by selecting resources by itself within the set resource pool. For example, the terminal can select resources by itself within a selection window by performing sensing and resource (re)selection procedures. For example, the sensing can be performed on a subchannel basis. For example, in step S610, the first terminal that has selected resources by itself within the resource pool transmits PSCCH (e.g., SCI (Sidelink Control Information) or 1) using the resources. st -stage SCI) can be transmitted to the second terminal. In step S620, the first terminal transmits the PSSCH (e.g., 2) related to the PSCCH. nd -stage SCI, MAC PDU, data, etc.) can be transmitted to the second terminal. In step S630, the first terminal can receive a PSFCH related to the PSCCH / PSSCH from the second terminal.

[0075] Referring to (a) or (b) of FIG. 6, for example, a first terminal may transmit an SCI to a second terminal on a PSCCH. Or, for example, the first terminal may transmit two consecutive SCIs (e.g., 2-stage SCIs) to the second terminal on the PSCCH and / or the PSSCH. In this case, the second terminal may decode the two consecutive SCIs (e.g., 2-stage SCIs) to receive the PSSCH from the first terminal. In the present specification, an SCI transmitted on a PSCCH is 1 st SCI, 1st SCI, 1st -stage SCI or 1 st -stage SCI format, and the SCI transmitted on the PSSCH is 2 nd SCI, 2nd SCI, 2 nd -stage SCI or 2 nd -It can be called a stage SCI format.

[0076] Referring to (a) or (b) of FIG. 6, in step S630, the first terminal may receive a PSFCH. For example, the first terminal and the second terminal may determine PSFCH resources, and the second terminal may use the PSFCH resources to transmit HARQ feedback to the first terminal.

[0077] Referring to (a) of FIG. 6, in step S640, the first terminal may transmit SL HARQ feedback to the base station via PUCCH and / or PUSCH.

[0078] FIG. 7 illustrates a communication structure that can be provided in a 6G system according to one embodiment of the present disclosure. The embodiment of FIG. 7 may be combined with various embodiments of the present disclosure, and some descriptions, functions, procedures, proposals, methods, and / or operations of the embodiments may be omitted.

[0079] As core implementation technologies of the 6G system, technologies such as artificial intelligence (AI), THz (terahertz) communication, optical wireless technology, free-space optical transmission (FSO) backhaul networks, massive MIMO (multiple input multiple output) technology, blockchain, 3D networking, quantum communication, unmanned aerial vehicles, cell-free communication, wireless information and energy transfer (WIET), integration of sensing and communication, integration of access backhaul networks, holographic beamforming, big data analysis, and large intelligent surface (LIS) can be adopted.

[0080] - Artificial Intelligence: Incorporating AI into communications can streamline and improve real-time data transmission. AI can use numerous analytics to determine how complex target tasks should be performed. For example, AI can increase efficiency and reduce processing delays. Time-consuming tasks such as handovers, network selection, and resource scheduling can be performed instantly using AI. AI can also play a crucial role in machine-to-machine (M2M), machine-to-human, and human-to-machine communications. AI can also facilitate rapid communication in brain-computer interfaces (BCIs). AI-based communication systems can be supported by metamaterials, intelligent structures, intelligent networks, intelligent devices, intelligent cognitive radios, self-sustaining wireless networks, and machine learning.

[0081] - THz communication (terahertz communication): Data rates can be increased by increasing the bandwidth. This can be achieved by using sub-THz communication with wide bandwidths and applying advanced massive MIMO technology. THz waves, also known as sub-millimeter waves, typically refer to the frequency range between 0.1 THz and 10 THz, with corresponding wavelengths ranging from 0.03 mm to 3 mm. The 100 GHz to 300 GHz band (sub-THz band) is considered a key part of the THz spectrum for cellular communications. Adding the sub-THz band to the mmWave band will increase the capacity of 6G cellular communications. Among the defined THz bands, 300 GHz to 3 THz lies in the far infrared (IR) frequency band. While part of the optical band, the 300 GHz to 3 THz band lies at the boundary of the optical band, immediately following the RF band. Therefore, this 300 GHz to 3 THz band exhibits similarities to RF. Key characteristics of THz communications include (i) the widely available bandwidth to support very high data rates and (ii) the high path loss that occurs at high frequencies (requiring highly directional antennas). The narrow beamwidths generated by highly directional antennas reduce interference. The small wavelength of THz signals allows for a significantly larger number of antenna elements to be integrated into devices and base stations operating in this band. This enables the use of advanced adaptive array technologies to overcome range limitations.

[0082] - Large-scale MIMO technology

[0083] - Hologram beamforming (HBF)

[0084] - Optical wireless technology

[0085] - Free-space optical transmission backhaul network (FSO backhaul network)

[0086] - Quantum communication

[0087] - Cell-free communication

[0088] - Integration of wireless information and power transmission

[0089] - Integration of wireless communication and sensing

[0090] - Integrated access and backhaul network

[0091] - Big data analysis

[0092] - Reconfigurable intelligent surface

[0093] - metaverse

[0094] - Block chain

[0095] Advanced Air Mobility (AAM): AAM can be a broad concept encompassing urban air mobility (UAM), regional air mobility (RAM), and uncrewed aerial systems (UAS). For example, AAM can include UAM, RAM, UAS, and uncrewed aerial vehicles (UAVs).

[0096] - Autonomous driving (self-driving): V2X (vehicle to everything), a key element in building autonomous driving infrastructure, can be a technology that allows cars to communicate and share with various elements on the road for autonomous driving, such as vehicle to vehicle (V2V) wireless communication and vehicle to infrastructure (V2I) wireless communication.

[0097] Non-terrestrial network (NTN): NTN can refer to a network or network segment that utilizes radio frequency (RF) resources mounted on satellites (or UAS platforms). NTN services may be considered to secure wider coverage or provide wireless communication services in locations where the installation of wireless communication base stations is difficult.

[0098] - Integrated sensing and communication (ISAC)

[0099] - Reconfigurable intelligent surface (RIS): RIS can be used to manipulate and enhance signal propagation in wireless communication environments. For example, a RIS can be composed of many small antennas, or metasurfaces, arranged on a surface, each of which can actively control the phase, amplitude, polarization, etc. of the reflected signal. For example, a RIS can improve signal reception by controlling the path, phase, and / or intensity of the propagating signal. For example, in the case of a RIS, power consumption can be very low because power is consumed only for controlling the phase and amplitude of the small antennas. For example, because a RIS can be reconfigured to suit different environments, it can meet diverse communication requirements and operate effectively in dynamic network environments.

[0100] FIG. 8 illustrates an example of a communication scenario based on a 6G system, according to an embodiment of the present disclosure. The embodiment of FIG. 8 may be combined with various embodiments of the present disclosure, and some descriptions, functions, procedures, proposals, methods, and / or operations of the embodiments may be omitted.

[0101] Referring to FIG. 8, NTN communication can be performed based on satellite networks, high-altitude platform stations (HAPS) as international mobile telecommunications (IMT) base stations (BS), terminals capable of aerial communication (e.g., AAM), etc. For example, to improve coverage, etc., devices such as satellite networks, HIBS, terminals capable of aerial communication (e.g., AAM), etc. can act as relays. For example, AAMs can communicate with base stations, satellite networks, etc., and / or AAMs can communicate directly with terminals, other AAMs, etc.

[0102] Below, the integrated sensing and communication (ISAC) mentioned above is described in detail.

[0103] Integrated Sensing and Communications (ISAC) is a technology that uses radio frequencies to determine the instantaneous linear velocity, angle, distance (range), etc. of an object, thereby obtaining information about the environment and / or the characteristics of objects within the environment. Because radio frequency sensing does not require a device to connect to the object through a network, it can provide services for object positioning without a device. The ability to obtain range, velocity, and angle information from radio frequency signals can enable a wide range of new capabilities, such as various object detection, object recognition (e.g., vehicles, humans, animals, UAVs), and high-precision localization, tracking, and activity recognition. Wireless sensing services can provide information to a variety of industries (e.g., unmanned aerial vehicles, smart homes, V2X, factories, railways, public safety, etc.), enabling applications such as intruder detection, assisted vehicle steering and navigation, trajectory tracking, collision avoidance, traffic management, and health and traffic management. In some cases, wireless sensing can utilize non-3GPP type sensors (e.g., radar, cameras) to further support 3GPP-based sensing. For example, the operation of a wireless sensing service (e.g., sensing operation) may depend on the transmission, reflection, and scattering processing of wireless sensing signals. Therefore, wireless sensing may provide an opportunity to enhance existing communication systems from communication networks to wireless communication and sensing networks. FIG. 9 illustrates an example of a sensing operation according to an embodiment of the present disclosure. The embodiment of FIG. 9 may be combined with various embodiments of the present disclosure, and some descriptions, functions, procedures, proposals, methods, and / or operations of the embodiments may be omitted. Specifically, FIG. 9 (a) illustrates an example of sensing using a sensing receiver and a sensing transmitter located at the same location (e.g., monostatic sensing), and FIG. 9 (b) illustrates an example of sensing using a separated sensing receiver and a sensing transmitter (e.g., bistatic sensing).

[0104] Meanwhile, in conventional LTE V2X, a terminal supporting multi-channel operation (e.g., multi-carrier operation or carrier aggregation (CA)) can select a specific carrier for transmitting sidelink data, select available resources on the selected carrier, and transmit sidelink data through the selected resources and carrier.

[0105] In this disclosure, we propose an operation of a terminal supporting multi-carrier operation when a carrier failure is detected. In addition, in this disclosure, we propose an operation for recovery when a carrier failure is detected in an out-of-coverage (OCC) terminal, an RRC inactive terminal, an RRC idle terminal, and an RRC connected terminal in a multi-carrier environment.

[0106] Meanwhile, the operations related to Tx carrier (re-)selection may be as follows.

[0107] For example, a MAC entity may consider the CBR measured by a lower layer as the carrier's CBR according to TS 38.215 if the CBR measurement result is available, and may consider the corresponding sl-defaultTxConfigIndex set by the upper layer if the CBR measurement result is not available.

[0108] For example, if Tx carrier (re)selection is triggered for a sidelink process according to Section 5.22.1.1, Section 5.22.1.2, or Section 5.22.1.3.3, the MAC entity can:

[0109] 1> If there is no selected sidelink grant on the allowed carrier for the sidelink logical channel on which data is available as indicated by the upper layer (TS 38.331 and TS 23.287):

[0110] 2> For each carrier configured at the upper layer associated with the concerned sidelink logical channel:

[0111] 3> If the carrier's CBR is lower than sl-threshCBR-FreqReselection, which is related to the priority of the sidelink logical channel:

[0112] Note: If multiple resource pools are configured for a carrier, the specific resource pool used to determine the CBR for that carrier may vary depending on the UE implementation and may take into account sl-HARQ-FeedbackEnabled for the sidelink logical channel.

[0113] 4> The above carrier may be considered as a candidate carrier for Tx carrier (re)selection for the concerned sidelink logical channel.

[0114] 1> If not:

[0115] 2> For each sidelink logical channel (if any) allowed on the carrier where data is available and Tx carrier (re)selection is triggered according to Section 5.22.1.1, if the carrier's CBR is lower than sl-threshCBR-FreqKeeping, which is related to the priority of the sidelink logical channel:

[0116] 3> The carrier and associated pool of resources can be selected.

[0117] 2> If not:

[0118] 3> For each carrier configured by the upper layer that allows sidelink logical channels, if the carrier's CBR is lower than sl-threshCBR-FreqReselection, which is associated with the priority of the sidelink logical channel:

[0119] 4> For each carrier configured by the upper layer that allows sidelink logical channels, the carrier may be considered as a candidate carrier for Tx carrier (re)selection.

[0120] For example, a MAC entity can:

[0121] 1> If more than one carrier is considered a candidate carrier for Tx carrier (re)selection:

[0122] 2> When Tx carrier (re)selection is triggered, for each sidelink logical channel on which data is allowed on the available carrier:

[0123] 3> One or more carriers can be selected from the candidate carriers in order of increasing CBR from the lowest CBR, and an associated resource pool can be selected.

[0124] 4> If sl-HARQ-FeedbackEnabled is set to enabled for the sidelink logical channel:

[0125] 5> One resource pool with PSFCH resources set can be selected from among the resource pools excluding the pool of sl-BWP-DiscPoolConfig or sl-BWP-DiscPoolConfigCommon (if set).

[0126] 4> If not:

[0127] 5> You can select a resource pool from among the resource pools other than those in sl-BWP-DiscPoolConfig or sl-BWP-DiscPoolConfigCommon (if set).

[0128] Note: How many carriers are selected may depend on UE implementation, depending on UE capability.

[0129] NOTE: It may be up to the UE implementation to determine which sidelink logical channels are available for data and which are allowed on which carrier Tx carrier (re)selection is triggered.

[0130] Note: It may be up to the UE implementation to decide whether to reuse the resource pool for CBR measurements as the resource pool for SL (sidelink) grant generation.

[0131] Meanwhile, the operation to detect carrier failure and radio link failure (RLF) based on discontinuous transmission (DTX) may be as follows.

[0132] For example, for each carrier associated with a PC5-RRC connection, a HARQ-based sidelink radio link failure (RLF) detection procedure can be used to detect sidelink RLF based on the number of consecutive DTXs of PSFCH reception occasions for the PC5-RRC connection.

[0133] RRC can set the following parameters to control HARQ-based sidelink RLF detection:

[0134] - sl-maxNumConsecutiveDTX.

[0135] The following UE variables can be used for HARQ-based sidelink RLF detection.

[0136] - numConsecutiveDTX: Per PC5-RRC connection per carrier can be maintained.

[0137] For example, for each carrier associated with a PC5-RRC connection, the sidelink HARQ entity may (re)initialize numConsecutiveDTX to 0 for each PC5-RRC connection established by the upper layer upon PC5-RRC connection establishment or sl-maxNumConsecutiveDTX (re)establishment.

[0138] For example, for each carrier associated with a PC5-RRC connection, the sidelink HARQ entity may do the following for each PSFCH reception occasion associated with a PSSCH transmission:

[0139] 1> If there is no PSFCH reception in a PSFCH reception occasion:

[0140] 2> numConsecutiveDTX can be increased by 1.

[0141] NOTE: For SL operation using shared spectrum channel access, the UE may increment numConsecutiveDTX by 1 if it does not detect HARQ feedback on all relevant PSFCH resources, as per clause 16.3.0 of TS 38.213.

[0142] 2> If two or more carriers selected as defined in Section 5.22.1.11 are considered carriers for HARQ-based sidelink RLF detection:

[0143] 3> When numConsecutiveDTX reaches sl-maxNumConsecutiveDTX for a carrier applied to HARQ-based sidelink RLF detection:

[0144] 4> As specified in Section 5.22.1.11, it may trigger a Tx carrier (re)selection procedure.

[0145] 4> HARQ-based sidelink carrier failure can be indicated to the upper layer.

[0146] 3> When numConsecutiveDTX reaches sl-maxNumConsecutiveDTX for all carriers applied to HARQ-based sidelink RLF detection:

[0147] 4> HARQ-based sidelink RLF detection can be indicated in the upper layer.

[0148] 2> Otherwise:

[0149] 3> When numConsecutiveDTX reaches sl-maxNumConsecutiveDTX:

[0150] 4> HARQ-based sidelink RLF detection can be indicated in the upper layer.

[0151] 1> Otherwise:

[0152] 2> numConsecutiveDTX can be reinitialized to 0.

[0153] Meanwhile, the action to terminate the carrier when a carrier failure is detected may be as follows.

[0154] For example, for NR sidelink communications, sidelink carrier release can be initiated when:

[0155] 1> In case of unicast, if the sl-Carrier-Id of the sidelink carrier is received in the sl-CarrierToReleaseList of RRCReconfigurationSidelink; or

[0156] 1> In case of unicast, if sidelink carrier failure is indicated at the MAC layer; or

[0157] 1> For unicast, if sidelink carrier release is triggered by sl-ConfigDedicatedNR, SIB12, SidelinkPreconfigNR, or a setting received from a higher layer; or

[0158] 1> For unicast, if the sidelink SRB, DRB or additional sidelink RLC bearer associated with the sidelink carrier is released according to Section 5.8.9.1a.3.1, Section 5.8.9.1a.1.1 or Section 5.8.9.1a.5.1;

[0159] For example, the UE can:

[0160] 1> For unicast, if sidelink carrier release is triggered by receiving an RRCReconfigurationSidelink message:

[0161] 2> For each sl-Carrier-Id value contained in sl-CarrierToReleaseList:

[0162] 3> If the current UE configuration contains a sidelink carrier with the sl-Carrier-Id value:

[0163] 4> The sidelink carrier can be released for reception.

[0164] 1> For unicast, if sidelink carrier release is triggered by the configuration received in sl-ConfigDedicatedNR, SIB12, SidelinkPreconfigNR or the configuration indicated by the upper layer after receiving the RRCReconfigurationCompleteSidelink message:

[0165] 2> For each sl-Carrier-Id value contained in sl-CarrierToReleaseList:

[0166] 3> If the current UE configuration contains a sidelink carrier with the sl-Carrier-Id value:

[0167] 4> The sidelink carrier can be released for transmission.

[0168] Meanwhile, actions related to sending a SidelinkUEInformationNR message may be as follows.

[0169] For example, the UE can set the contents of the SidelinkUEInformationNR message as follows.

[0170] 1> When the UE initiates a procedure indicating that it is not interested in receiving NR sidelink communications / positioning; or

[0171] 1> When the UE initiates a procedure to request (set up / release) NR sidelink communication / positioning transmission resources or to report to the network that a sidelink radio link failure, sidelink RRC reconfiguration failure, or sidelink carrier failure has been declared;

[0172] 2> When sidelink carrier failure is indicated at the MAC layer;

[0173] 3> sl-CarrierFailureList can be included and the following fields can be set for each destination reporting a sidelink carrier failure:

[0174] 4> sl-DestinationIdentity can be set to the destination ID where the sidelink carrier failure is indicated.

[0175] 4> sl-CarrierFailure can be set to include carriers that indicate sidelink carrier failure.

[0176] Meanwhile, the dedicated sidelink configuration could be as follows:

[0177] For example, upon initiating the above procedure, the UE may:

[0178] 1> If sl-FreqInfoToReleaseList is included in sl-ConfigDedicatedNR within RRCReconfiguration:

[0179] 2> For each entry contained in the received sl-FreqInfoToReleaseList that is part of the current UE configuration:

[0180] 3> Related configurations can be released from the saved NR sidelink communication / discovery configuration.

[0181] Meanwhile, in the present disclosure, when a carrier failure is detected, a procedure is proposed for updating a set of carriers allowed for a logical channel associated with a carrier in which a carrier failure is detected.

[0182] For example, according to the above-described prior art, when a transmitting terminal detects a carrier failure (e.g., when a DTX (e.g., an event of not receiving a PSFCH for a PSCCH / PSSCH transmission) on a specific carrier occurs a preset threshold number of times, the transmitting terminal may declare a carrier failure for the corresponding carrier) on a specific sidelink carrier (or one of the selected carriers, or all the selected carriers, or all the configured available carriers), the transmitting terminal may report the carrier failure to a higher layer (e.g., an RRC layer). For example, when the higher layer receives a report of a carrier failure from the MAC layer, the upper layer may release (or remove) the carrier on which the reported carrier failure is detected from the candidate carrier (or carrier set) used by the terminal (or the allowed carrier set per logical channel, or the allowed carrier per logical channel). For example, the terminal may select a carrier to use for data transmission by considering newly updated carriers (or carrier sets) that have been released (or removed) from the RRC layer (e.g., Tx carrier (re)selection procedure). In addition, for example, the terminal may declare an RLF and terminate all unicast links and / or all PC5 RRC connections if a carrier failure occurs in all carriers configured from the RRC layer.

[0183] However, for example, in the above-described prior art, the following problems may occur. For example, the RRC layer may set {Carrier #1, Carrier #2, Carrier #3} among the available carriers {Carrier #1, Carrier #2, Carrier #3, Carrier #4, Carrier #5, Carrier #6, Carrier #7, Carrier #8, Carrier #9} as carriers allowed for transmission of logical channel #A (or, QoS (quality of service) flow related to logical channel #A). And, for example, {Carrier #4, Carrier #5, Carrier #6} may be set as carriers allowed for transmission of logical channel #B (or, QoS flow related to logical channel #B). Also, for example, the transmitting terminal may perform a Tx carrier (re)selection procedure to select a carrier for data transmission of logical channel #A, and may determine the carrier to use (based on the lowest CBR (channel busy ratio)) in the order of carrier #1, carrier #2, and carrier #3. In this case, for example, according to the above-described prior art, if carrier failure occurs in all of carrier #1, carrier #2, and carrier #3, the RRC layer may release (or remove) carrier #1, carrier #2, and carrier #3 from the set of carriers allowed for transmission of logical channel #A. In this case, for example, the terminal may not declare an RLF because there are remaining carriers allowed for transmission of logical channel #B, etc. However, for example, a problem may arise where the terminal cannot perform transmission of logical channel #A permanently (or continuously) even though the unicast link is not in a RLF declared state (unicast link release and / or PC5 RRC connection release) because there is no carrier to use for transmission of logical channel #A.

[0184] Therefore, in the present disclosure, when a carrier failure occurs, in addition to the operation of releasing (or removing) the carrier in which the carrier failure occurred from the carrier set at the RRC layer as in the prior art, a carrier addition procedure is proposed to add a new carrier to the available carriers, as follows.

[0185] For example, in the above-described embodiment, if a carrier failure is declared for carrier #1 among the carriers {carrier #1, carrier #2, carrier #3} allowed for transmission of logical channel #A, the RRC layer may perform a procedure for adding carrier #7 as a new carrier to the set of carriers allowed for transmission of logical channel #A. For example, the terminal may transmit newly added carrier information through this carrier addition procedure to the counterpart terminal (e.g., the counterpart terminal for establishing a unicast connection or the counterpart terminal for establishing a PC5 RRC connection) via a PC5 RRC message. For example, the carriers allowed for transmission of logical channel #A may be updated to {carrier #2, carrier #3, carrier #7}.

[0186] Alternatively, for example, if carrier failure is declared for carrier #1, carrier #2, and carrier #3 in the carriers {carrier #1, carrier #2, and carrier #3} allowed for transmission of logical channel #A, the RRC layer may perform a procedure to add carrier #7, carrier #8, and carrier #9 as new carriers to the set of carriers allowed for transmission of logical channel #A.

[0187] Alternatively, for example, if a carrier failure is declared for "Carrier #1" or "Carrier #1, Carrier #2, Carrier #3" in the allowed carriers {Carrier #1, Carrier #2, Carrier #3} for transmission on logical channel #A, the RRC layer may update the carrier configuration of logical channel #A to allow the use of other allowed carriers (e.g., the allowed carrier set {Carrier #4, Carrier #5, Carrier #6} for logical channel #B) together with the allowed carrier set for transmission on logical channel #A (e.g., "Carrier #2, Carrier #3, Carrier #4, Carrier #5" or "Carrier #4, Carrier #5", etc.). For example, the allowed carriers for transmission on logical channel #A may be updated to {Carrier #7, Carrier #8, Carrier #9}. And, for example, the MAC layer can perform Tx carrier (re)selection based on the updated carrier set information {Carrier #7, Carrier #8, Carrier #9} and continue transmitting logical channel #A data using the selected carrier.

[0188] Additionally, for example, when the carrier (or carrier set) allowed for a logical channel is reset by the RRC layer (e.g., when a new carrier is added, or in the case of carrier modification that adds a carrier allowed for another logical channel to the set of carriers allowed for its own logical channel, or when all the carriers allowed for a specific logical channel are reset to new carriers), the transmitting terminal can trigger a Tx carrier (re)selection procedure to perform carrier selection again for data transmission based on the reset carrier (or carrier set).

[0189] Alternatively, for example, the RRC layer can define an exception carrier that can be used exceptionally when a carrier failure occurs for all carriers configured for each logical channel. For example, if a carrier failure is declared for all carriers {Carrier #1, Carrier #2, Carrier #3} allowed for transmission of logical channel #A, the transmitting terminal can continue transmission of logical channel #A using the exception carrier configured in the RRC layer.

[0190] Alternatively, for example, even if a carrier failure occurs at the MAC layer, the RRC layer may not remove the carrier where the carrier failure occurred from the carrier list. And, for example, the transmitting terminal may trigger a Tx carrier (re)selection procedure whenever a carrier failure occurs, so as to perform CBR measurement again for the carrier where the carrier failure occurred. For example, if the CBR measurement value for the carrier where the carrier failure occurred is below a threshold (e.g., sl-threshCBR-FreqReselection or sl-threshCBR-FreqKeeping), the carrier where the carrier failure occurred may be used again to perform data transmission.

[0191] Meanwhile, according to the prior art, the base station can receive a report of carrier failure from the terminal and include the corresponding carrier in the sl-FreqInfoToReleaseList, thereby preventing the terminal from using the carrier included in the sl-FreqInfoToReleaseList for sidelink transmission or reception. However, in this case, even though the transmitting terminal does not have a carrier failure in any available carrier and thus no RLF is declared, as described above, a problem may occur in which the transmitting terminal cannot transmit the logical channel data (or the QoS flow related to the logical channel data) because all carriers for the specific logical channel data (or the QoS flow related to the logical channel data) are released (or removed).

[0192] Accordingly, according to an embodiment proposed in the present disclosure, as a solution of the base station to solve this, when the base station includes a carrier in which a carrier failure reported from a terminal has occurred in the sl-FreqInfoToReleaseList, a timer (e.g., set or pre-configured by the base station) can be started, and when the timer reaches a threshold time or expires, the carrier in which the carrier failure is declared included in the sl-FreqInfoToReleaseList can be deleted to refresh (or reconfigure) the sl-FreqInfoToReleaseList configuration. And, for example, a terminal that has received sl-FreqInfoToReleaseList that has been refreshed (or reconfigured) from a base station can transmit the carrier information (e.g., sl-CarrierToReleaseList) deleted from sl-FreqInfoToReleaseList to a counterpart terminal (e.g., a unicast-connected counterpart (receiving) terminal) via a PC5 RRC message (or can indicate to the counterpart terminal via sl-CarrierToAddModList that a carrier for which a carrier failure has been declared can be used again).

[0193] Meanwhile, for example, the base station can configure one or more carriers {sl-FreqInfoToAddModList / sl-FreqInfoToAddModListExt(Carrier #1, Carrier #2, Carrier #3, Carrier #4, Carrier #5, Carrier #6, Carrier #7, Carrier #8, Carrier #9)} to be used by the terminal and transmit them to the terminal (e.g., via a dedicated RRC message and / or system information and / or pre-configuration). In addition, for example, a higher layer of the terminal (e.g., V2X layer) can configure {Carrier #1, Carrier #2, Carrier #3} as allowed carriers for transmission of a specific service #a (e.g., destination layer-2 ID or a specific QoS flow). And, for example, {Carrier #4, Carrier #5, Carrier #6} can be set as the carriers allowed for transmission of a specific service #b (e.g., destination layer-2 ID or specific QoS flow). Also, for example, the transmitting terminal can perform a Tx carrier (re)selection procedure to select a carrier for data transmission of service #a, and determine the carrier to use in the order of carrier #1, carrier #2, and carrier #3 (based on the lowest CBR (channel busy ratio)).

[0194] In this case, for example, according to the prior art, if carrier failure occurs in all of carrier #1, carrier #2, and carrier #3, the RRC layer may release carrier #1, carrier #2, and carrier #3 from the set of carriers allowed for data transmission related to service #a (e.g., destination layer-2 ID or specific QoS flow). In this case, for example, the terminal may not declare an RLF because there are still carriers allowed to be used for transmission of service #b (e.g., destination layer-2 ID or specific QoS flow), and there are still carriers to be used in the available carriers {sl-FreqInfoToAddModList / sl-FreqInfoToAddModListExt (carrier #1, carrier #2, carrier #3, carrier #4, carrier #5, carrier #6, carrier #7, carrier #8, carrier #9)} configured by the base station. However, for example, a problem may arise where the terminal cannot perform data transmission related to service #a (e.g., destination layer-2 ID or specific QoS flow) permanently (or continuously) even though the unicast link is not in a RLF declared state (unicast link release and / or PC5 RRC connection release) because there is no carrier to use for data transmission related to service #a (e.g., destination layer-2 ID or specific QoS flow).

[0195] Accordingly, according to the embodiment proposed in the present disclosure, if a carrier failure occurs in all carriers {Carrier #1, Carrier #2, Carrier #3} allowed for transmission of service #a (e.g., destination layer-2 ID or specific QoS flow), the base station may select one of the other available carriers configured by the base station (e.g., carriers {Carrier #4, Carrier #5, Carrier #6} allowed for transmission of service #b (e.g., destination layer-2 ID or specific QoS flow) or sl-FreqInfoToAddModList / sl-FreqInfoToAddModListExt (Carrier #7, Carrier #8, Carrier #9)) to continue data transmission related to service #a (e.g., destination layer-2 ID or specific QoS flow).

[0196] Alternatively, for example, according to the prior art, when a terminal declares a carrier failure, the terminal may report the carrier failure to the base station and transmit information about the carrier for which the carrier failure was declared together. For example, when the base station receives a report of a carrier failure from the terminal, the base station may include the corresponding carrier in sl-FreqInfoToReleaseList and update the carrier configuration (e.g., sl-FreqInfoToReleaseList) and transmit it to the terminal. For example, when the terminal receives updated carrier configuration information (e.g., sl-FreqInfoToReleaseList) from the base station, the terminal may delete the carrier included in the sl-FreqInfoToReleaseList from the stored (or used) carriers (or carrier list) for sidelink data transmission. For example, the carrier included in the sl-FreqInfoToReleaseList may be excluded from the carrier (or carrier list) for sidelink data transmission (or TX carrier (re)selection procedure).

[0197] According to an embodiment proposed in the present disclosure, a timer (e.g., Carrier_Resume_Timer) may be defined for the purpose of allowing carrier(s) included in the sl-FreqInfoToReleaseList to be reused for sidelink data transmission (or, TX carrier (re)selection procedure). For example, when the base station receives a carrier failure report, the base station may start the timer, and when the timer expires, the base station may delete the carrier for which the carrier failure has been declared from the sl-FreqInfoToReleaseList, reset the carrier configuration, and transmit the reset carrier information to the terminal. In addition, for example, the transmitting terminal may also indicate to the opposite receiving terminal via a PC5 RRC message that the carrier for which the carrier failure has been declared is to be reused (e.g., add information about the carrier to be reused to sl-CarrierToAddModList). Or, for example, the terminal may start the Carrier_Resume_Timer when it declares a carrier failure. And, for example, even if the terminal receives sl-FreqInfoToReleaseList containing a carrier for which a carrier failure has been declared from the base station, the terminal may reuse the carrier for which the carrier failure has been declared for sidelink data transmission (or, TX carrier (re)selection procedure) when the Carrier_Resume_Timer has expired. In addition, for example, the transmitting terminal may also indicate to the receiving terminal that the carrier for which the carrier failure has been declared is to be reused via a PC5 RRC message (e.g., adding information about the carrier to be reused to sl-CarrierToAddModList).

[0198] Meanwhile, for example, when the terminal detects an event in which it does not receive HARQ feedback for PSCCH / PSSCH transmission on the corresponding carrier (e.g., when DTX detects a threshold value or more), the terminal may start a timer (e.g., a carrier recovery timer: configured or pre-configured by the base station) and may continue to perform PSSCH / PSSCH transmission on the corresponding carrier while the timer is running. For example, if it does not receive one or more PSCCH / PSSCH from the opposite receiving terminal until the timer expires, the terminal may declare a carrier failure and report the carrier failure to the base station (e.g., the index of the carrier on which the carrier failure is declared). In addition, for example, the terminal that declared the carrier failure may transmit information on the carrier on which the carrier failure is declared to the opposite receiving terminal via a PC5 RRC message. Additionally, for example, a terminal that has declared a carrier failure can indicate to the counterpart terminal via a PC5 RRC message that the carrier can be used again (e.g., carrier resume) after a certain period of time (e.g., set by the base station or pre-configuration) after transmitting carrier information related to the carrier failure to the counterpart terminal.

[0199] Meanwhile, in this disclosure, a carrier addition procedure is proposed as follows.

[0200] For example, for NR sidelink communication, sidelink carrier addition can be initiated in the following cases:

[0201] 1> In case of unicast, if the sl-Carrier-Id of the sidelink carrier is received in the sl-CarrierToAddModList of RRCReconfigurationSidelink; or

[0202] 1> For unicast, if the sl-Carrier-Id of the sidelink carrier is received in the sl-CarrierToAddModList of RRCReconfigurationCompleteSidelink; or

[0203] 1> For unicast, if the sidelink SRB, DRB or additional sidelink RLC bearer associated with the sidelink carrier (taking into account the carrier mapped to the sidelink QoS flow configured in the upper layer, the carrier configured in sl-ConfigDedicatedNR, SIB12 or SidelinkPreconfigNR, and the carrier supported by both UEs) is configured according to Section 5.8.9.1a.4, Section 5.8.9.1a.2.1 or Section 5.8.9.1a.6.1; or

[0204] 1> For unicast, when a sidelink carrier failure is detected (or indicated) (at the MAC layer); or

[0205] 1> In case of unicast, after a certain period of time (e.g., set or pre-configuration by the base station) has expired after a carrier failure is indicated from the MAC layer;

[0206] For example, the UE can:

[0207] 1> For unicast, if sidelink carrier addition is triggered by carrier failure:

[0208] 2> For each sl-Carrier-Id value contained in sl-CarrierToAddModList that does not belong to the current UE configuration (e.g., sidelink carrier addition) (e.g., this action could be interpreted as adding a carrier other than the one for which carrier failure was declared):

[0209] 3> For reception, a sidelink carrier corresponding to sl-Carrier-Id can be added according to sl-AbsoluteFrequencyPointA.

[0210] 1> For unicast, after a certain period of time (e.g., set or pre-configuration by the base station) has elapsed after a carrier failure is indicated from the MAC layer:

[0211] 2> For each sl-Carrier-Id value contained in sl-CarrierToAddModList that is (or is not) part of the current UE configuration (e.g., sidelink carrier addition) (e.g., this action could be interpreted as considering a carrier that has declared carrier failure as a reusable carrier):

[0212] 3> For reception, a sidelink carrier corresponding to sl-Carrier-Id can be added according to sl-AbsoluteFrequencyPointA.

[0213] 1> For unicast, if sidelink carrier addition is triggered by receiving an RRCReconfigurationSidelink message:

[0214] 2> For each sl-Carrier-Id value contained in sl-CarrierToAddModList that does not belong to the current UE configuration (e.g., sidelink carrier addition):

[0215] 3> A sidelink carrier corresponding to sl-Carrier-Id can be added according to sl-AbsoluteFrequencyPointA for reception.

[0216] 1> For unicast, if sidelink carrier addition is triggered by the configuration received in sl-ConfigDedicatedNR, SIB12, SidelinkPreconfigNR or the configuration indicated by the upper layer after receiving the RRCReconfigurationCompleteSidelink message:

[0217] 2> For each sl-Carrier-Id value contained in sl-CarrierToAddModList that is not part of the current UE configuration (e.g., sidelink carrier addition):

[0218] 3> A sidelink carrier corresponding to sl-Carrier-Id can be added for transmission according to sl-AbsoluteFrequencyPointA.

[0219] Meanwhile, for example, the base station can configure one or more carriers {sl-FreqInfoToAddModList / sl-FreqInfoToAddModListExt (Carrier #1, Carrier #2, Carrier #3, Carrier #4, Carrier #5, Carrier #6, Carrier #7, Carrier #8, Carrier #9)} to be used by the terminal and transmit them to the terminal (e.g., dedicated RRC message and / or system information and / or pre-configuration). In addition, for example, the upper layer of the terminal (e.g., V2X layer) can configure {Carrier #1, Carrier #2, Carrier #3} as carriers allowed for transmission of a specific service #a (e.g., destination layer-2 ID or specific QoS flow). And, for example, {Carrier #4, Carrier #5, Carrier #6} can be set as the carriers allowed for transmission of a specific service #b (e.g., destination layer-2 ID or specific QoS flow). Also, for example, the transmitting terminal can perform a Tx carrier (re)selection procedure to select a carrier for data transmission of service #a, and determine the carrier to use in the order of carrier #1, carrier #2, and carrier #3 (based on the lowest CBR (channel busy ratio)).

[0220] In this case, for example, according to the prior art, if carrier failures occur in all of carrier #1, carrier #2, and carrier #3, the RRC layer may release (or remove) carrier #1, carrier #2, and carrier #3 from the set of carriers allowed for data transmission related to service #a (e.g., destination layer-2 ID or specific QoS flow). In this case, for example, the terminal may not declare an RLF because there are still carriers allowed to be used for transmission of service #b (e.g., destination layer-2 ID or specific QoS flow), and there are still carriers to be used in the available carriers {sl-FreqInfoToAddModList / sl-FreqInfoToAddModListExt (carrier #1, carrier #2, carrier #3, carrier #4, carrier #5, carrier #6, carrier #7, carrier #8, carrier #9)} configured by the base station. However, for example, a problem may arise where the terminal cannot perform data transmission related to service #a (e.g., destination layer-2 ID or specific QoS flow) permanently (or continuously) even though the unicast link is not in a state where RLF is declared (unicast link termination and / or PC5 RRC connection termination) because there is no carrier to use for data transmission related to service #a (e.g., destination layer-2 ID or specific QoS flow).

[0221] Therefore, according to the embodiment proposed in the present disclosure, if a carrier failure occurs in all carriers {Carrier #1, Carrier #2, Carrier #3} that are allowed to transmit service #a (e.g., destination layer-2 ID or specific QoS flow), the upper layer (e.g., V2X layer or RRC layer) can release (or remove) the SL data communication for service #a (e.g., destination layer-2 ID or specific QoS flow) and notify the AS (access stratum) layer of this. In addition, for example, when the AS layer is instructed to release (or remove) SL data communication for service #a (e.g., destination layer-2 ID or specific QoS flow) from a higher layer (e.g., V2X layer or RRC layer), the AS layer may clear the Mode 1 grant allocated or the Mode 2 grant generated for the service #a (e.g., destination layer-2 ID or specific QoS flow). In addition, for example, when the terminal performs the Mode 1 operation, the base station may report an ACK (acknowledgement) to the PUCCH (physical uplink control channel) so that the base station does not allocate any more Mode 1 (re)transmission resources for service #a (e.g., destination layer-2 ID or specific QoS flow). Also, for example, the AS layer receives service #a (e.g., from a higher layer (e.g., V2X layer or RRC layer)When termination of SL data communication for a destination layer-2 ID or a specific QoS flow is instructed, parameters (e.g., numConsecutiveDTX, initialize SBj to 0 for each logical channel associated with service #a (e.g., destination layer-2 ID or specific QoS flow)) associated with all MACs running for that service #a (e.g., destination layer-2 ID or specific QoS flow), timers (e.g., all timers associated with service #a (e.g., destination layer-2 ID or specific QoS flow) (if running)), and procedures (e.g., triggered sidelink consistent listen before talk (LBT) failure, triggered sidelink Consistent beam failure recovery, triggered sidelink DRX command indication, triggered sidelink channel state information (CSI) reporting, triggered sidelink inter-UE coordination (IUC) information reporting, triggered sidelink inter-UE coordination (IUC) request transmission, triggered sidelink buffer status report (BSR) procedure relevant only to service #a (e.g., destination layer-2 ID or specific QoS flow), service #a (e.g.,A triggered scheduling request (SR) procedure related only to a destination layer-2 ID or a specific QoS flow may be stopped and / or canceled and / or reset. In addition, for example, the terminal may consider all sidelink processes related to service #a (e.g., destination layer-2 ID or a specific QoS flow) as unoccupied. Alternatively, for example, when the AS layer is instructed by a higher layer (e.g., V2X layer or RRC layer) to release (or remove) SL data communication for service #a (e.g., destination layer-2 ID or specific QoS flow), the AS layer may perform a MAC reset operation for the service #a (e.g., destination layer-2 ID or specific QoS flow). In addition, for example, when a carrier failure occurs in a carrier or a set of carriers associated with a specific service #a (e.g., a destination layer-2 ID or a specific QoS flow), the terminal may report information about the carrier failure (e.g., a carrier index for the carrier where the carrier failure occurred, a carrier failure indication, or a carrier failure cause) to a higher layer (e.g., the terminal may declare a carrier failure when DTX exceeds a threshold for PSCCH / PSSCH transmission using a specific carrier).

[0222] The terminal (or UE) mentioned in the present disclosure may be alternatively interpreted as an RRC connected terminal (or UE) and / or an RRC idle terminal (or UE) and / or an RRC inactive terminal (or UE) and / or an OOC (out of coverage) terminal (or UE).

[0223] The present disclosure (or a part of the present disclosure) is a solution that can be applied not only to an RRC CONNECTED terminal that is connected to a base station, but also to an RRC idle, RRC inactive, or OOC (out of coverage) terminal that is not connected to a base station.

[0224] Meanwhile, in the present disclosure, a method for declaring carrier failure or RLF (radio link failure) of a terminal during multi-carrier operation and a device supporting the same are proposed as follows.

[0225] For example, according to the prior art, the terminal may consider the carrier(s) containing the resource pool for which the carrier CBR measurement value is below the threshold and the PSFCH is set as the concerned carrier for the carrier failure or SL (sidelink) RLF (radio link failure) declaration operation during the Tx carrier (re)selection process triggered according to the above section 5.22.1.1.

[0226] In this case, for example, according to the above-described prior art, the following error may occur in the operation for carrier failure or RLF declaration. For example, if the terminal satisfies the condition that carrier A is a carrier including a resource pool in which a carrier CBR measurement value is less than or equal to a threshold and a PSFCH is configured, the terminal may determine the carrier A as a concerned carrier to be used for the carrier failure or SL RLF declaration operation. And, for example, the terminal may generate a sidelink grant based on the resources of the resource pool included in the carrier A, and may perform a carrier failure or RLF detection and declaration operation while performing HARQ feedback enabled logical channel data transmission based on the generated grant. In this case, for example, if the terminal transmits PSCCH / PSSCH for carrier A and fails to receive HARQ feedback multiple times, such that the DTX count reaches "7", and the DTX threshold for carrier failure is considered to be "10", the terminal may re-check whether the CBR measurements for the carriers are above or below the threshold when the TX carrier (re)selection procedure is triggered. In this case, for example, if the CBR of carrier A, where DTX occurred 7 times, is measured to be above the threshold, the terminal may exclude carrier A from the concerned carrier(s) for the carrier failure or SL RLF declaration operation. For example, a problem may occur in that the ongoing DTX counting operation of carrier A is reset. For example, this may cause a problem in that the terminal's monitoring operation for the current channel status (e.g., DTX) is stopped, so that the channel status cannot be accurately reflected.

[0227] Additionally, according to the prior art, the Tx carrier (re)selection procedure may be triggered not only when a link (or connection) needs to be re-established due to a declaration of radio link failure (RLF), but also when resource selection fails or data (e.g., MAC PDU) transmission fails due to listen before talk (LBT) failure. For example, if carrier A is selected as a candidate carrier based on a Tx carrier selection procedure, and then a Tx carrier reselection procedure is triggered for a reason other than a link (or connection) reset due to an RLF declaration (e.g., if the DTX count set for carrier A does not reach the DTX threshold and thus no RLF has occurred, but the Tx carrier selection procedure is triggered again for another reason), even though there is still a possibility that transmission can be performed based on carrier A because no RLF has been declared yet, carrier A may be excluded as a candidate carrier for the Tx carrier reselection procedure simply because the re-measured CBR for carrier A is greater than or equal to the threshold, which may result in a degradation of communication performance (e.g., latency). Alternatively, even if, for example, Tx carrier reselection is triggered and the re-measured CBR for carrier A exceeds the threshold, this may be because the CBR of carrier A temporarily exceeds the threshold due to a temporary change in the communication environment.Even though there is room to continue transmission based on Carrier A because the DTX count of Carrier A has not reached the DTX threshold, if the carrier is excluded from the candidate carriers simply because the CBR of the carrier exceeds the threshold, the problem of reduced efficiency in resource use may occur (in short, even though there may be limitations in judging the condition of the channel in an actual communication environment using only the CBR, if the decision on whether to include the carrier in the candidate carrier is made based only on the CBR, inefficiency in communication resource use may occur.).

[0228] Accordingly, according to the embodiment proposed in the present disclosure, if a DTX counting operation was being performed on the concerned carrier(s) used for carrier failure or SL RLF declaration when TX carrier (re)selection is triggered (e.g., carrier(s) having a DTX counting value greater than or equal to 1 and less than a DTX threshold), even if the CBR of the corresponding carrier is remeasured and the CBR value is greater than or equal to the threshold, the corresponding carrier can be continued to be used as the concerned carrier for carrier failure or SL RLF declaration without excluding it from the set of concerned carriers for carrier failure or SL RLF declaration. For example, if the DTX counting of a given carrier (e.g., a carrier with a CBR measurement greater than or equal to the threshold) reaches its max (or DTX threshold) (e.g., a carrier failure declaration or SL RLF declaration) or is reset (e.g., set to 0), it may be excluded from the set of concerned carriers for a carrier failure or SL RLF declaration.

[0229] FIG. 10 illustrates a carrier (re)selection method according to an embodiment of the present disclosure. The embodiment of FIG. 10 may be combined with various embodiments of the present disclosure, and some descriptions, functions, procedures, proposals, methods, and / or operations of the embodiments may be omitted.

[0230] FIG. 10 (a) illustrates a case where carrier selection is triggered. For example, when carrier selection is triggered for the Tx UE, the CBR (channel busy ratio) for each of multiple carriers (carrier #1, carrier #2, carrier # (see FIG. 10 (a))) can be measured. For example, for convenience of explanation, when the CBR measurement value and the CBR threshold are expressed numerically, the CBR threshold can be set to "20", the CBR measurement value of carrier #1 can be "10", the CBR measurement value of carrier #2 can be "5", and the CBR measurement value of carrier #3 can be "20". In this case, for example, since the CBR measurement values ​​of carrier #1 and carrier #2 are lower than the CBR threshold, carrier #1 and carrier #2 can be included in the candidate carriers, and since the CBR measurement value of carrier #3 is equal to or greater than the CBR threshold, carrier #3 cannot be included in the candidate carriers. And, for example, among carrier #1 and carrier #2 included in the candidate carriers, carrier #2, which has the lowest CBR measurement value, may be first selected as a carrier for HARQ-based SL RLF declaration. In this case, for example, when a Tx UE performs PSSCH transmission based on carrier #2 but there is no PSFCH reception for the PSSCH from the Rx UE, the value of the DTX counter set in carrier #2 may increase, and when the value of the DTX counter accumulated due to repeated PSSCH transmission and PSFCH reception failure reaches a DTX threshold, carrier failure may be declared / detected for carrier #2. And, for example, among the candidate carriers, carrier #1, which has the next lowest CBR measurement value after carrier #2, may be selected as a carrier for HARQ-based SL RLF declaration. For example, as described above, if the Tx UE performs PSSCH transmission based on carrier #1, but there is no PSFCH reception for the PSSCH from the Rx UE, the value of the DTX counter set for carrier #1 may be increased.Meanwhile, carrier reselection (see (b) of Fig. 10) may be triggered for other reasons even though the value of the DTX counter set to carrier #1 is 1 or more due to the absence of PSFCH reception but the DTX threshold has not yet been reached and SL RLF has not been declared.

[0231] FIG. 10 (b) illustrates a case where carrier reselection is triggered. For example, even when carrier reselection is triggered for the Tx UE, CBR measurements may be performed again for each of multiple carriers (Carrier #1, Carrier #2, Carrier # (see FIG. 10 (b))). For example, due to a temporary change in the communication environment, the re-measured CBR measurement value may be different from that in FIG. 10 (a) described above. For example, the CBR re-measured value of Carrier #1 may be "20", the CBR re-measured value of Carrier #2 may be "30", and the CBR re-measured value of Carrier #3 may be "10". In this case, for example, since the CBR re-measured value of Carrier #3 is lower than the CBR threshold, Carrier #2 may be included in the candidate carriers of the carrier reselection procedure. And, for example, since the CBR re-measured value of Carrier #2 exceeds the CBR threshold, Carrier #3 cannot be included in the candidate carriers of the carrier reselection procedure. Meanwhile, for example, in the case of carrier #1, even if the CBR re-measured value of carrier #1 is equal to or greater than the CBR threshold, if the DTX counter value set for carrier #1 does not reach the DTX threshold, as in the proposal of the present disclosure, carrier #1 may also be included in the candidate carriers for the carrier reselection procedure. And, for example, among carrier #1 and carrier #3 included in the candidate carriers for the carrier reselection procedure, carrier #3, which has the lowest CBR measured value, may be selected first as a carrier for HARQ-based SL RLF declaration. In this case, for example, if a Tx UE performs PSSCH transmission based on carrier #3, but there is no PSFCH reception for the PSSCH from the Rx UE, the value of the DTX counter set for carrier #3 may be increased, and if the value of the DTX counter accumulated by repeated PSSCH transmission and PSFCH reception failure reaches the DTX threshold, a carrier failure may be declared / detected for carrier #3.And, for example, among the candidate carriers, carrier #1 with the next lowest CBR measurement value after carrier #3 can be selected as the carrier for HARQ-based SL RLF declaration. In this case, for example, the Tx UE can continue to perform PSSCH transmission based on the reselected carrier #1. For example, the Tx UE can continue to monitor the channel status while continuing to perform DTX counting based on the reselected carrier #1.

[0232] In summary, when carrier reselection is triggered, if the CBR of the existing carrier is greater than or equal to the CBR threshold (e.g., sl-threshCBR-FreqKeeping, or sl-threshCBR-FreqReselection), and if the DTX count of the existing carrier (e.g., numConsecutiveDTX) is greater than or equal to 1 and less than the DTX threshold (e.g., sl-maxNumConsecutiveDTX), the existing carrier can be considered as a candidate carrier for Tx carrier (re)selection.

[0233] FIG. 11 illustrates a carrier (re)selection method according to an embodiment of the present disclosure. The embodiment of FIG. 11 may be combined with various embodiments of the present disclosure, and some descriptions, functions, procedures, proposals, methods, and / or operations of the embodiments may be omitted.

[0234] Referring to FIG. 11, in step S1110, a Tx UE that has acquired configuration information related to multiple carriers may trigger carrier selection. In step S1120, the Tx UE may perform CBR measurement for each of the multiple carriers, and may select a first carrier among the multiple carriers based on a CBR measurement value of the first carrier being less than a CBR threshold. Specifically, for example, candidate carriers may be determined as one or more carriers associated with a CBR less than the CBR threshold among the multiple carriers, and a carrier with the lowest CBR among one or more carriers included in the candidate carriers may be selected as a carrier for HARQ-based SL RLF detection. For example, among one or more carriers included in the candidate carriers, the first carrier may be selected as a carrier for HARQ-based SL RLF detection. In step S1130, the Tx UE may transmit a physical shared channel (e.g., PSSCH) based on the first carrier. In step S1140, the Tx UE may fail to receive a physical feedback channel (e.g., PSFCH) for the physical shared channel (e.g., PSSCH) transmission. In step S1150, based on the absence of reception of a physical feedback channel (e.g., PSFCH) for the physical shared channel (e.g., PSSCH) transmission, the value of the DTX counter set for the first carrier may be increased. For example, when the Tx UE repeats steps S1130 and S1140 described above, DTX counting related to the first carrier may be cumulatively performed. In step S1160, carrier reselection may be triggered for a reason other than an RLF declaration even though the value of the DTX counter set for the first carrier in step S1150 described above has not yet reached the DTX threshold. In step S1170, the Tx UE may perform CBR measurement for each of the plurality of carriers again, as in step S1120 described above.For example, unlike the step S1120 described above, it may be checked that the re-measured CBR for the first carrier is greater than the CBR threshold. In step S1180, the Tx UE may not immediately exclude the first carrier from the candidate carriers based on the re-measured CBR of the first carrier being greater than the CBR threshold, but may check the DTX count set for the first carrier. In this case, for example, if the DTX count set for the first carrier is greater than 0 (e.g., not initialized) and less than the DTX threshold (e.g., DTX counting is in progress based on the first carrier, and the DTX count set for the first carrier has not yet reached the DTX threshold), the first carrier may be included in the candidate carriers. For example, even if the re-measured CBR of the first carrier exceeds the CBR threshold, if DTX counting is in progress based on the first carrier, the Tx UE may maintain the first carrier selected in the carrier selection prior to carrier reselection. For example, even if the re-measured CBR of the first carrier exceeds the CBR threshold, if the DTX count set for the first carrier is 1 or more and less than the DTX threshold, the first carrier selected in the carrier selection prior to carrier reselection may be re-selected as a carrier for HARQ-based SL RLF detection.

[0235] The wording of multi-carrier as specified in this disclosure may be extended to carrier aggregation (CA).

[0236] The CBR threshold associated with a sidelink carrier / SL sidelink bandwidth part (BWP) / SL HARQ entity specified in the present disclosure can be set per priority, per QoS profile (e.g., packet delay budget (PDB) or reliability), per SL radio bearer, or per logical channel.

[0237] The wording of the sidelink carrier specified in this disclosure may be extended to a sidelink BWP or a sidelink HARQ entity.

[0238] The unicast service specified in this disclosure may be interpreted as a pair of source layer-2 ID and destination layer-2 ID.

[0239] The groupcast service specified in this disclosure may be interpreted as a groupcast destination layer-2 ID.

[0240] The broadcast service specified in this disclosure may be interpreted as a broadcast destination layer-2 ID.

[0241] The term “carrier” as specified in the present disclosure may be replaced with “band” or “set of resource blocks (RBs) of a specific carrier” or “set of resource pools of a specific carrier” or “channel” or “radio frequency”.

[0242] The carrier failure specified in this disclosure may be replaced with radio frequency failure.

[0243] The wording of release as specified in this disclosure may be applied by replacing it with remove.

[0244] The PC5 RRC connection or unicast link specified in this disclosure may be applied as a replacement for a PC5 unicast link.

[0245] For example, whether (some) of the proposed methods / rules of the present disclosure are applicable and / or related parameters (e.g., thresholds) may be set specifically (or differently or independently) for SL-Channel Access Priority Class (CAPC). For example, whether (some) of the proposed methods / rules of the present disclosure are applicable and / or related parameters (e.g., thresholds) may be set specifically (or differently or independently) for SL-LBT types (e.g., Type 1 LBT, Type 2A LBT, Type 2B LTB, Type 2C LBT). For example, whether (some) of the proposed methods / rules of the present disclosure are applicable and / or related parameters (e.g., thresholds) may be set specifically (or differently or independently) depending on whether FBE (Frame Based LBT) is applied. For example, whether (some) of the proposed methods / rules of the present disclosure are applicable and / or the relevant parameters (e.g., thresholds) may be set specifically (or differently or independently) depending on whether LBE (Load Based LBT) is applied.

[0246] For example, whether (some) of the proposed methods / rules of the present disclosure are applicable and / or their associated parameters (e.g., thresholds) can be set resource pool-specifically (or differently or independently). For example, whether (some) of the proposed methods / rules of the present disclosure are applicable and / or their associated parameters (e.g., thresholds) can be set congestion level-specifically (or differently or independently). For example, whether (some) of the proposed methods / rules of the present disclosure are applicable and / or their associated parameters (e.g., thresholds) can be set service priority-specifically (or differently or independently). For example, whether (some) of the proposed methods / rules of the present disclosure are applicable and / or their associated parameters (e.g., thresholds) can be set service type-specifically (or differently or independently). For example, whether (some) of the proposed schemes / rules of the present disclosure are applicable and / or related parameters (e.g., thresholds) can be set specifically (or differently or independently) for QoS requirements (e.g., latency, reliability). For example, whether (some) of the proposed schemes / rules of the present disclosure are applicable and / or related parameters (e.g., thresholds) can be set specifically (or differently or independently) for PQI (5QI (5G QoS identifier) ​​for PC5). For example, whether (some) of the proposed schemes / rules of the present disclosure are applicable and / or related parameters (e.g., thresholds) can be set specifically (or differently or independently) for traffic types (e.g., periodic generation or aperiodic generation). For example, whether (some) of the proposed schemes / rules of the present disclosure are applicable and / or related parameters (e.g., thresholds) can be set specifically (or differently or independently) for SL transmission resource allocation modes (e.g., mode 1 or mode 2).For example, whether (some) of the proposed methods / rules of the present disclosure are applicable and / or related parameters (e.g., thresholds) may be configured specifically (or differently or independently) for a Tx profile (e.g., a Tx profile indicating that the service supports sidelink DRX operation or a Tx profile indicating that the service does not need to support sidelink DRX operation).

[0247] For example, whether the proposed rule of the present disclosure applies and / or the related parameter setting values ​​can be specifically (or differently or independently) set depending on whether PUCCH configuration is supported (e.g., when PUCCH resources are configured or when PUCCH resources are not configured). For example, whether the proposed rule of the present disclosure applies and / or the related parameter setting values ​​can be specifically (or differently or independently) set for a resource pool (e.g., a resource pool where PSFCH is configured or a resource pool where PSFCH is not configured). For example, whether the proposed rule of the present disclosure applies and / or the related parameter setting values ​​can be specifically (or differently or independently) set for a type of service / packet. For example, whether the proposed rule of the present disclosure applies and / or the related parameter setting values ​​can be specifically (or differently or independently) set for a priority of a service / packet. For example, whether the proposed rule of the present disclosure applies and / or the related parameter setting values ​​can be set specifically (or differently or independently) for a QoS profile or QoS requirement (e.g., URLLC / EMBB traffic, reliability, latency). For example, whether the proposed rule of the present disclosure applies and / or the related parameter setting values ​​can be set specifically (or differently or independently) for a PQI. For example, whether the proposed rule of the present disclosure applies and / or the related parameter setting values ​​can be set specifically (or differently or independently) for a PFI. For example, whether the proposed rule of the present disclosure applies and / or the related parameter setting values ​​can be set specifically (or differently or independently) for a cast type (e.g., unicast, groupcast, broadcast). For example, whether the proposed rule of the present disclosure applies and / or the related parameter setting values ​​can be set specifically (or differently or independently) for a (resource pool) congestion level (e.g., CBR).For example, whether the proposed rule of the present disclosure is applicable and / or the related parameter setting value can be set specifically (or differently or independently) for an SL HARQ feedback scheme (e.g., NACK-only feedback, ACK / NACK feedback). For example, whether the proposed rule of the present disclosure is applicable and / or the related parameter setting value can be set specifically (or differently or independently) for HARQ Feedback Enabled MAC PDU transmission. For example, whether the proposed rule of the present disclosure is applicable and / or the related parameter setting value can be set specifically (or differently or independently) for HARQ Feedback Disabled MAC PDU transmission. For example, whether the proposed rule of the present disclosure is applicable and / or the related parameter setting value can be set specifically (or differently or independently) depending on whether a PUCCH-based SL HARQ feedback reporting operation is set. For example, whether the proposed rule of the present disclosure applies and / or the related parameter setting values ​​can be set specifically (or differently or independently) depending on whether pre-emption or pre-emption-based resource reselection is performed. For example, whether the proposed rule of the present disclosure applies and / or the related parameter setting values ​​can be set specifically (or differently or independently) depending on whether re-evaluation or re-evaluation-based resource reselection is performed. For example, whether the proposed rule of the present disclosure applies and / or the related parameter setting values ​​can be set specifically (or differently or independently) for (L2 or L1) (source and / or destination) identifiers. For example, whether the proposed rule of the present disclosure applies and / or the related parameter setting values ​​can be set specifically (or differently or independently) for (L2 or L1) (a combination of source ID and destination ID) identifiers.For example, whether the proposed rule of the present disclosure applies and / or the related parameter setting values ​​can be set specifically (or differently or independently) for an identifier (L2 or L1) (a combination of a pair of source ID and destination ID and a cast type). For example, whether the proposed rule of the present disclosure applies and / or the related parameter setting values ​​can be set specifically (or differently or independently) for a direction of a pair of source layer ID and destination layer ID. For example, whether the proposed rule of the present disclosure applies and / or the related parameter setting values ​​can be set specifically (or differently or independently) for a PC5 RRC connection / link. For example, whether the proposed rule of the present disclosure applies and / or the related parameter setting values ​​can be set specifically (or differently or independently) depending on whether SL DRX is performed. For example, whether the proposed rule of the present disclosure applies and / or the related parameter setting values ​​can be set specifically (or differently or independently) depending on whether SL DRX is supported. For example, whether the proposed rule of the present disclosure applies and / or the related parameter setting values ​​can be set specifically (or differently or independently) for the SL mode type (e.g., resource allocation mode 1 or resource allocation mode 2). For example, whether the proposed rule of the present disclosure applies and / or the related parameter setting values ​​can be set specifically (or differently or independently) for the case of performing (a)periodic resource reservation. For example, whether the proposed rule of the present disclosure applies and / or the related parameter setting values ​​can be set specifically (or differently or independently) for a Tx profile (e.g., a Tx profile indicating that the service supports sidelink DRX operation or a Tx profile indicating that the service does not need to support sidelink DRX operation).

[0248] The applicability of the proposals and proposed rules of the present disclosure (and / or the associated parameter settings) may also be applied to mmWave SL operation.

[0249] FIG. 12 illustrates a method for a first device to perform wireless communication according to an embodiment of the present disclosure. The embodiment of FIG. 12 may be combined with various embodiments of the present disclosure, and some descriptions, functions, procedures, proposals, methods, and / or operations of the embodiments may be omitted.

[0250] Referring to FIG. 12, in step S1210, the first device may obtain configuration information related to the first carrier. In step S1220, the first device may obtain information related to the channel congestion of the first carrier. For example, whether to include the first carrier in the candidate carrier may be determined based on the channel congestion of the first carrier and the value of a discontinuous transmission (DTX) counter related to the first carrier.

[0251] For example, based on a value of a DTX counter associated with the first carrier being greater than or equal to 1 and less than a DTX threshold, the first carrier may be included in the candidate carriers.

[0252] For example, based on (i) a channel congestion of the first carrier being greater than or equal to a threshold value, and (ii) a value of a DTX counter associated with the first carrier being greater than or equal to 1 and less than a DTX threshold value, the first carrier may be included in the candidate carriers. For example, among one or more carriers included in the candidate carriers, the first carrier may be selected as a carrier for hybrid automatic repeat request (HARQ)-based SL (sidelink) RLF (radio link failure) detection. For example, among at least one carrier selected as a carrier for HARQ-based SL RLF detection, a channel congestion of the first carrier may be higher than a channel congestion of a carrier other than the first carrier.

[0253] For example, whether to include the first carrier in the candidate carriers may be determined based on a second carrier selection triggered after the first carrier selection. And, for example, based on the first carrier being selected as a carrier for HARQ-based SL RLF detection in the first carrier selection, a value of a DTX counter associated with the first carrier may be increased after the first carrier selection. Additionally, for example, the first device may transmit a physical shared channel to the second device based on the first carrier. For example, based on the absence of reception of a physical feedback channel associated with transmission of the physical shared channel from the second device, a value of a DTX counter associated with the first carrier may be increased. For example, a value of a DTX counter associated with the first carrier may not reach a DTX threshold until the second carrier selection is triggered.

[0254] For example, the first carrier associated with the channel congestion greater than or equal to a threshold value may not be excluded from the candidate carriers based on the value of the DTX counter associated with the first carrier being greater than or equal to 1 and less than the DTX threshold value.

[0255] For example, a value of a DTX counter associated with the first carrier that is greater than or equal to 1 and less than a DTX threshold may not be initialized based on the channel congestion of the first carrier being greater than the threshold.

[0256] For example, the resource pool associated with the first carrier may be a resource pool for which a physical feedback channel is established.

[0257] For example, the channel congestion of the first carrier can be obtained based on the number of sub-channels associated with a received signal strength indicator (RSSI) greater than or equal to a threshold value among a plurality of sub-channels included in the first carrier.

[0258] For example, the first carrier may not be included in the candidate carriers based on (i) the channel congestion of the first carrier being greater than or equal to a threshold, and (ii) the value of the DTX counter associated with the first carrier reaching the DTX threshold.

[0259] The proposed method can be applied to devices according to various embodiments of the present disclosure. First, the processor (102) of the first device (100) can control the transceiver (106) to obtain configuration information related to a first carrier. In addition, the processor (102) of the first device (100) can obtain information related to the channel congestion of the first carrier. For example, whether to include the first carrier in the candidate carrier can be based on the channel congestion of the first carrier and the value of a discontinuous transmission (DTX) counter related to the first carrier.

[0260] According to one embodiment of the present disclosure, a first device configured to perform wireless communication may be provided. For example, the first device may include at least one transceiver; at least one processor; and at least one memory coupled to the at least one processor and storing instructions. For example, the instructions, based on execution by the at least one processor, may cause the first device to: obtain configuration information related to a first carrier; and obtain information related to channel congestion of the first carrier. For example, whether to include the first carrier in a candidate carrier may be determined based on the channel congestion of the first carrier and the value of a discontinuous transmission (DTX) counter related to the first carrier.

[0261] According to one embodiment of the present disclosure, a processing device configured to control a first device may be provided. For example, the processing device may include at least one processor; and at least one memory coupled to the at least one processor and storing instructions. For example, the instructions, based on execution by the at least one processor, may cause the first device to: obtain configuration information related to a first carrier; and obtain information related to channel congestion of the first carrier. For example, whether to include the first carrier in a candidate carrier may be determined based on the channel congestion of the first carrier and the value of a discontinuous transmission (DTX) counter related to the first carrier.

[0262] According to one embodiment of the present disclosure, a non-transitory computer-readable storage medium having instructions recorded thereon may be provided. For example, the instructions, when executed, may cause a first device to: obtain configuration information related to a first carrier; and obtain information related to channel congestion of the first carrier. For example, whether to include the first carrier in a candidate carrier may be determined based on the channel congestion of the first carrier and the value of a discontinuous transmission (DTX) counter related to the first carrier.

[0263] FIG. 13 illustrates a method for a second device to perform wireless communication according to an embodiment of the present disclosure. The embodiment of FIG. 13 may be combined with various embodiments of the present disclosure, and some descriptions, functions, procedures, proposals, methods, and / or operations of the embodiments may be omitted.

[0264] Referring to FIG. 13, in step S1310, the second device may obtain configuration information related to the first carrier. In step S1320, the second device may monitor a physical shared channel based on the configuration information related to the first carrier. For example, the first carrier may be a carrier selected for hybrid automatic repeat request (HARQ)-based SL (sidelink) RLF (radio link failure) detection based on a channel congestion level of the first carrier and a value of a discontinuous transmission (DTX) counter related to the first carrier.

[0265] The proposed method can be applied to devices according to various embodiments of the present disclosure. First, the processor (202) of the second device (200) can control the transceiver (206) to obtain configuration information related to a first carrier. Then, the processor (202) of the second device (200) can control the transceiver (206) to monitor a physical shared channel based on the configuration information related to the first carrier. For example, the first carrier can be a carrier selected for hybrid automatic repeat request (HARQ)-based SL (sidelink) RLF (radio link failure) detection based on the channel congestion of the first carrier and the value of a discontinuous transmission (DTX) counter related to the first carrier.

[0266] According to one embodiment of the present disclosure, a second device configured to perform wireless communication may be provided. For example, the second device may include at least one transceiver; at least one processor; and at least one memory coupled to the at least one processor and storing instructions. For example, the instructions, based on execution by the at least one processor, may cause the second device to: obtain configuration information related to a first carrier; and monitor a physical shared channel based on the configuration information related to the first carrier. For example, the first carrier may be a carrier selected for hybrid automatic repeat request (HARQ)-based sidelink (SL) RLF (radio link failure) detection based on a channel congestion level of the first carrier and a value of a discontinuous transmission (DTX) counter related to the first carrier.

[0267] According to one embodiment of the present disclosure, a processing device configured to control a second device may be provided. For example, the processing device may include at least one processor; and at least one memory coupled to the at least one processor and storing instructions. For example, the instructions, based on execution by the at least one processor, may cause the second device to: obtain configuration information related to a first carrier; and monitor a physical shared channel based on the configuration information related to the first carrier. For example, the first carrier may be a carrier selected for hybrid automatic repeat request (HARQ)-based sidelink (SL) RLF (radio link failure) detection based on a channel congestion level of the first carrier and a value of a discontinuous transmission (DTX) counter related to the first carrier.

[0268] According to one embodiment of the present disclosure, a non-transitory computer-readable storage medium having instructions recorded thereon may be provided. For example, the instructions, when executed, may cause a second device to: obtain configuration information related to a first carrier; and monitor a physical shared channel based on the configuration information related to the first carrier. For example, the first carrier may be a carrier selected for hybrid automatic repeat request (HARQ)-based sidelink (SL) radio link failure (RLF) detection based on channel congestion of the first carrier and a value of a discontinuous transmission (DTX) counter related to the first carrier.

[0269] According to various embodiments of the present disclosure, in Tx carrier (re)selection, even if the CBR of the carrier is equal to or greater than the CBR threshold, if DTX counting is being performed for the carrier (if the DTX count of the carrier is equal to or greater than 1 and less than the DTX threshold), the carrier can be determined as a candidate carrier for Tx carrier (re)selection. In this case, for example, even if the CBR of the carrier is equal to or greater than the CBR threshold, since the DTX count set for the carrier has not reached the threshold, an opportunity for transmission based on the carrier can be secured. Alternatively, for example, if a carrier whose DTX count has not reached the DTX threshold is excluded and another carrier is determined as a candidate carrier, if there is no PSFCH reception for a PSSCH transmitted on the other carrier, an RLF must be declared and the link (or connection) must be reset (or reestablished), but if a carrier whose DTX count has not reached the DTX threshold is maintained even if the CBR of the carrier exceeds the CBR threshold, there is no need to reset (or reestablish) the link, so unnecessary link resets (or reestablishes) can be reduced and the stability of the network can be improved. Alternatively, for example, in the procedure for selecting a candidate carrier, not only the CBR measurement for the carrier but also the state of the DTX counter set for the carrier can be additionally considered, so that the flexibility of carrier selection can be improved. Or, for example, since there may be limitations in judging the status of a channel in an actual communication environment using only the CBR measurement value of the carrier, the rationality of carrier selection can be improved and the efficiency of resource use can be improved by selecting a carrier by considering not only the short-term CBR change of the carrier but also the status of the DTX counter.

[0270] The various embodiments of the present disclosure may be combined with each other.

[0271] Below, a description is given of devices to which various embodiments of the present disclosure can be applied.

[0272] Although not limited thereto, the various descriptions, functions, procedures, proposals, methods and / or operational flowcharts disclosed in this document may be applied to various fields requiring wireless communication / connectivity (e.g., 5G) between devices.

[0273] Hereinafter, more specific examples will be provided with reference to the drawings. In the drawings / descriptions below, the same drawing reference numerals may represent identical or corresponding hardware blocks, software blocks, or functional blocks, unless otherwise described.

[0274] Fig. 14 illustrates a communication system (1) according to one embodiment of the present disclosure. The embodiment of Fig. 14 may be combined with various embodiments of the present disclosure, and some descriptions, functions, procedures, proposals, methods, and / or operations of the embodiments may be omitted.

[0275] Referring to FIG. 14, a communication system (1) to which various embodiments of the present disclosure are applied includes a wireless device, a base station, and a network. Here, the wireless device refers to a device that performs communication using a 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 Things) device (100f), and an AI device / server (400). For example, the vehicle may include a vehicle equipped with a wireless communication function, an autonomous vehicle, a vehicle capable of performing vehicle-to-vehicle communication, etc. Here, the vehicle may include an Unmanned Aerial Vehicle (UAV) (e.g., a drone) and / or an Aerial Vehicle (AV) (e.g., an Advanced Air Mobility (AAM)). The XR device may include an Augmented Reality (AR) / Virtual Reality (VR) / Mixed Reality (MR) device, and may be implemented in the form of a Head-Mounted Device (HMD), a Head-Up Display (HUD) equipped in a vehicle, a television, a smartphone, a computer, a wearable device, a home appliance, a digital signage, a vehicle, a robot, etc. The portable device may include a smartphone, a smart pad, a wearable device (e.g., a smart watch, smart glasses), a computer (e.g., a laptop, etc.), etc. The home appliance may include a TV, a refrigerator, a washing machine, etc. The IoT device may include a sensor, a smart meter, etc. For example, a base station and a network may also be implemented as a wireless device, and a specific wireless device (200a) may operate as a base station / network node to other wireless devices.

[0276] Here, the wireless communication technology implemented in the wireless devices (100a to 100f) of the present specification may include not only LTE, NR, and 6G, but also Narrowband Internet of Things for low-power communication. At this time, for example, NB-IoT technology may be an example of LPWAN (Low Power Wide Area Network) technology, and may be implemented with standards such as LTE Cat NB1 and / or LTE Cat NB2, and is not limited to the above-described names. Additionally or alternatively, the wireless communication technology implemented in the wireless devices (100a to 100f) of the present specification may perform communication based on LTE-M technology. At this time, for example, LTE-M technology may be an example of LPWAN technology, and may be called by various names such as eMTC (enhanced Machine Type Communication). For example, LTE-M technology can be implemented by 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 above-described names. Additionally or alternatively, the wireless communication technology implemented in the wireless devices (100a to 100f) of the present specification can include at least one of ZigBee, Bluetooth, and Low Power Wide Area Network (LPWAN) considering low-power communication, and is not limited to the above-described names. For example, ZigBee technology can create personal area networks (PAN) related to small / low-power digital communication based on various standards such as IEEE 802.15.4, and can be called by various names.

[0277] Wireless devices (100a to 100f) can be connected to a network (300) via a base station (200). Artificial Intelligence (AI) technology can be applied to the wireless devices (100a to 100f), and the wireless devices (100a to 100f) can be connected to an AI server (400) via the network (300). The network (300) can be configured using a 3G network, a 4G (e.g., LTE) network, a 5G (e.g., NR) network, etc. The wireless devices (100a to 100f) can communicate with each other via the base station (200) / network (300), but can 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). In addition, IoT devices (e.g., sensors) can communicate directly with other IoT devices (e.g., sensors) or other wireless devices (100a to 100f).

[0278] Wireless communication / connection (150a, 150b, 150c) can be established between wireless devices (100a~100f) / base stations (200), and base stations (200) / base stations (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 base station-to-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 each other. For example, wireless communication / connection (150a, 150b, 150c) can transmit / receive signals through various physical channels. To this end, at least some of 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.), and resource allocation processes can be performed based on various proposals of the present disclosure.

[0279] FIG. 15 illustrates a wireless device according to an embodiment of the present disclosure. The embodiment of FIG. 15 may be combined with various embodiments of the present disclosure, and some descriptions, functions, procedures, proposals, methods, and / or operations of the embodiments may be omitted.

[0280] Referring to FIG. 15, the first wireless device (100) and the second wireless device (200) can transmit and receive wireless signals via various wireless access technologies (e.g., LTE, NR). Here, {the first wireless device (100), the second wireless device (200)} can correspond to {the wireless device (100x), the base station (200)} and / or {the wireless device (100x), the wireless device (100x)} of FIG. 14.

[0281] A first wireless device (100) includes one or more processors (102) and one or more memories (104), and may further include one or more transceivers (106) and / or one or more antennas (108). The processor (102) controls the memories (104) and / or the transceivers (106), and may be configured to implement the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in this document. For example, the processor (102) may process information in the memory (104) to generate first information / signal, and then transmit a wireless signal including the first information / signal via the transceiver (106). Furthermore, the processor (102) may receive a wireless signal including second information / signal via the transceiver (106), and then store information obtained from 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 perform some or all of the processes controlled by the processor (102), or may store software code including commands for performing the descriptions, functions, procedures, proposals, methods, and / or operation flowcharts disclosed in this document. Here, the processor (102) and the memory (104) may be part of a communication modem / circuit / chip designed to implement a 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 via one or more antennas (108). The transceiver (106) may include a transmitter and / or a receiver. The transceiver (106) may be used interchangeably with an RF (Radio Frequency) unit. In the present disclosure, a wireless device may also mean a communication modem / circuit / chip.

[0282] A second wireless device (200) includes one or more processors (202), one or more memories (204), and may further include one or more transceivers (206) and / or one or more antennas (208). The processor (202) controls the memories (204) and / or the transceivers (206), and may be configured to implement the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in this document. For example, the processor (202) may process information in the memory (204) to generate third information / signals, and then transmit a wireless signal including the third information / signals via the transceivers (206). In addition, the processor (202) may receive a wireless signal including fourth information / signals via the transceivers (206), and then store information obtained from signal processing of the fourth information / signals 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 perform some or all of the processes controlled by the processor (202), or may store software code including commands for performing the descriptions, functions, procedures, proposals, methods, and / or operation flowcharts 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 via one or more antennas (208). The transceiver (206) may include a transmitter and / or a receiver. The transceiver (206) may be used interchangeably with an RF unit. In the present disclosure, a wireless device may also mean a communication modem / circuit / chip.

[0283] Hereinafter, the 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 one or more Service Data Units (SDUs) according to the descriptions, functions, procedures, proposals, methods, and / or operation flowcharts 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 operation flowcharts disclosed in this document. One or more processors (102, 202) can generate signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data or information according to the functions, procedures, proposals and / or methods disclosed herein, and provide the signals to one or more transceivers (106, 206). One or more processors (102, 202) can receive signals (e.g., baseband signals) from one or more transceivers (106, 206) and obtain PDUs, SDUs, messages, control information, data or information according to the descriptions, functions, procedures, proposals, methods and / or operational flowcharts disclosed herein.

[0284] One or more processors (102, 202) may be referred to as a controller, a microcontroller, a microprocessor, or a 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 operational 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. The descriptions, functions, procedures, suggestions, methods and / or operation flowcharts disclosed in this document may be implemented using firmware or software configured to perform one or more processors (102, 202) or stored in one or more memories (104, 204) and executed by one or more processors (102, 202). The descriptions, functions, procedures, suggestions, methods and / or operation flowcharts disclosed in this document may be implemented using firmware or software in the form of codes, instructions and / or sets of instructions.

[0285] One or more memories (104, 204) may be coupled to one or more processors (102, 202) and may store various forms of data, signals, messages, information, programs, codes, instructions, and / or commands. The one or more memories (104, 204) may be configured as ROM, RAM, EPROM, flash memory, hard drives, registers, cache memory, computer-readable storage media, and / or combinations thereof. The one or more memories (104, 204) may be located internally and / or externally to the one or more processors (102, 202). Additionally, the one or more memories (104, 204) may be coupled to the one or more processors (102, 202) via various technologies, such as wired or wireless connections.

[0286] One or more transceivers (106, 206) can transmit user data, control information, wireless signals / channels, etc., as mentioned in the methods and / or flowcharts of this document, to one or more other devices. One or more transceivers (106, 206) can receive user data, control information, wireless signals / channels, etc., as mentioned in the descriptions, functions, procedures, proposals, methods and / or flowcharts of this document, from one or more other devices. For example, one or more transceivers (106, 206) can be connected to one or more processors (102, 202) and can transmit and receive wireless signals. For example, one or more processors (102, 202) can 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 coupled 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, or the like, as referred to in the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed herein, via 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 received user data, control information, wireless signals / channels, etc. from RF band signals to baseband signals in order to process the received user data, control information, wireless signals / channels, etc. using one or more processors (102, 202).One or more transceivers (106, 206) may convert user data, control information, wireless signals / channels, etc. processed by one or more processors (102, 202) from baseband signals to RF band signals. For this purpose, one or more transceivers (106, 206) may include an (analog) oscillator and / or filter.

[0287] Fig. 16 illustrates a signal processing circuit for a transmission signal according to an embodiment of the present disclosure. The embodiment of Fig. 16 may be combined with various embodiments of the present disclosure, and some descriptions, functions, procedures, proposals, methods, and / or operations of the embodiments may be omitted.

[0288] Referring to FIG. 16, the signal processing circuit (1000) may include a scrambler (1010), a modulator (1020), a layer mapper (1030), a precoder (1040), a resource mapper (1050), and a signal generator (1060). Although not limited thereto, the operations / functions of FIG. 16 may be performed in the processor (102, 202) and / or the transceiver (106, 206) of FIG. 15. The hardware elements of FIG. 16 may be implemented in the processor (102, 202) and / or the transceiver (106, 206) of FIG. 15. For example, blocks 1010 to 1060 may be implemented in the processor (102, 202) of FIG. 15. Additionally, blocks 1010 to 1050 may be implemented in the processor (102, 202) of FIG. 15, and block 1060 may be implemented in the transceiver (106, 206) of FIG. 15.

[0289] The codeword can be converted into a wireless signal through the signal processing circuit (1000) of FIG. 16. Here, the codeword is an encoded bit sequence of an information block. The information block can include a transport block (e.g., an UL-SCH transport block, a DL-SCH transport block). The wireless signal can be transmitted through various physical channels (e.g., a PUSCH or a PDSCH).

[0290] Specifically, the codeword can be converted into a bit sequence scrambled by a scrambler (1010). The scramble sequence used for scrambling is generated based on an initialization value, and the initialization value may include ID information of the wireless device, etc. The scrambled bit sequence can be modulated into a modulation symbol sequence by a modulator (1020). The modulation method may include pi / 2-BPSK (pi / 2-Binary Phase Shift Keying), m-PSK (m-Phase Shift Keying), m-QAM (m-Quadrature Amplitude Modulation), etc. The complex modulation symbol sequence can be mapped to one or more transmission layers by a layer mapper (1030). The modulation symbols of each transmission layer can be mapped to the corresponding antenna port(s) by a precoder (1040) (precoding). The output z of the precoder (1040) can be obtained by multiplying the output y of the layer mapper (1030) by a precoding matrix W of N*M. Here, N is the number of antenna ports, and M is the number of transmission layers. Here, the precoder (1040) can perform precoding after performing transform precoding (e.g., DFT transform) on complex modulation symbols. In addition, the precoder (1040) can perform precoding without performing transform precoding.

[0291] The resource mapper (1050) can map modulation symbols of each antenna port to time-frequency resources. The time-frequency resources can include multiple symbols (e.g., CP-OFDMA symbols, DFT-s-OFDMA symbols) in the time domain and multiple subcarriers in the frequency domain. The signal generator (1060) generates a wireless signal from the mapped modulation symbols, and the generated wireless signal can be transmitted to another device through each antenna. To this end, the signal generator (1060) can include an Inverse Fast Fourier Transform (IFFT) module, a Cyclic Prefix (CP) inserter, a Digital-to-Analog Converter (DAC), a frequency uplink converter, etc.

[0292] The signal processing process for receiving signals in a wireless device can be configured in reverse order of the signal processing process (1010 to 1060) of FIG. 16. For example, a wireless device (e.g., 100, 200 of FIG. 15) can receive wireless signals from the outside through an antenna port / transceiver. The received wireless signals can be converted into baseband signals through a signal restorer. For this purpose, the signal restorer can include a frequency downlink converter, an analog-to-digital converter (ADC), a CP remover, and a fast Fourier transform (FFT) module. Thereafter, the baseband signal can be restored to a codeword through a resource demapper process, a postcoding process, a demodulation process, and a descrambling process. The codewords can be restored to the original information blocks through decoding. Accordingly, a signal processing circuit (not shown) for a received signal may include a signal restorer, a resource de-mapper, a postcoder, a demodulator, a de-scrambler, and a decoder.

[0293] Figure 17 illustrates a wireless device according to an embodiment of the present disclosure. The wireless device may be implemented in various forms depending on the use case / service (see Figure 14). The embodiment of Figure 17 may be combined with various embodiments of the present disclosure, and some descriptions, functions, procedures, proposals, methods, and / or operations of the embodiments may be omitted.

[0294] Referring to FIG. 17, the wireless device (100, 200) corresponds to the wireless device (100, 200) of FIG. 15 and may be composed of various elements, components, units / units, 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 a 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. 15. For example, the transceiver(s) (114) may include one or more transceivers (106, 206) and / or one or more antennas (108, 208) of FIG. 15. The control unit (120) is electrically connected to the communication unit (110), the memory unit (130), and the additional elements (140) and controls the overall operation of the wireless device. For example, the control unit (120) may control the electrical / mechanical operation of the wireless device based on the program / code / command / information stored in the memory unit (130). In addition, the control unit (120) may transmit information stored in the memory unit (130) to an external device (e.g., another communication device) via a wireless / wired interface through the communication unit (110), or store information received from an external device (e.g., another communication device) via a wireless / wired interface in the memory unit (130).

[0295] The additional element (140) may be configured in various ways depending on the type of the 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. 14, 100a), a vehicle (Fig. 14, 100b-1, 100b-2), an XR device (Fig. 14, 100c), a portable device (Fig. 14, 100d), a home appliance (Fig. 14, 100e), an IoT device (Fig. 14, 100f), a digital broadcasting terminal, a hologram device, a public safety device, an MTC device, a medical device, a fintech device (or a financial device), a security device, a climate / environmental device, an AI server / device (Fig. 14, 400), a base station (Fig. 14, 200), a network node, etc. Wireless devices may be mobile or stationary depending on the use / service.

[0296] In FIG. 17, various elements, components, units / parts, and / or modules within the wireless device (100, 200) may be interconnected entirely via a wired interface, or at least some 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). In addition, each element, component, unit / part, and / or module within the wireless device (100, 200) may further include one or more elements. For example, the control unit (120) may be composed of one or more processor sets. 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 a random access memory (RAM), a dynamic RAM (DRAM), a read only memory (ROM), a flash memory, a volatile memory, a non-volatile memory, and / or a combination thereof.

[0297] Below, the implementation example of Fig. 17 is described in more detail with reference to the drawings.

[0298] FIG. 18 illustrates a mobile device according to an embodiment of the present disclosure. The mobile device may include a smartphone, a smart pad, a wearable device (e.g., a smartwatch, smartglasses), or a portable computer (e.g., a laptop, etc.). The mobile device may be referred to as a Mobile Station (MS), a User Terminal (UT), a Mobile Subscriber Station (MSS), a Subscriber Station (SS), an Advanced Mobile Station (AMS), or a Wireless Terminal (WT). The embodiment of FIG. 18 may be combined with various embodiments of the present disclosure, and some descriptions, functions, procedures, proposals, methods, and / or operations of the embodiments may be omitted.

[0299] Referring to FIG. 18, the portable device (100) may include an antenna unit (108), a communication unit (110), a control unit (120), a memory unit (130), a power supply unit (140a), an interface unit (140b), and an input / output unit (140c). The antenna unit (108) may be configured as a part of the communication unit (110). Blocks 110 to 130 / 140a to 140c correspond to blocks 110 to 130 / 140 of FIG. 17, respectively.

[0300] The communication unit (110) can transmit and receive signals (e.g., data, control signals, etc.) with other wireless devices and base stations. The control unit (120) can control components of the mobile device (100) to perform various operations. The control unit (120) can include an AP (Application Processor). The memory unit (130) can store data / parameters / programs / codes / commands required for operating the mobile device (100). In addition, the memory unit (130) can store input / output data / information, etc. The power supply unit (140a) supplies power to the mobile device (100) and can include a wired / wireless charging circuit, a battery, etc. The interface unit (140b) can support connection between the mobile device (100) and other external devices. The interface unit (140b) can include various ports (e.g., audio input / output ports, video input / output ports) for connection with external devices. The input / output unit (140c) can input or output video information / signals, audio information / signals, data, and / or information input from a user. The input / output unit (140c) may include a camera, a microphone, a user input unit, a display unit (140d), a speaker, and / or a haptic module.

[0301] For example, in the case of data communication, the input / output unit (140c) obtains information / signals (e.g., touch, text, voice, image, video) input by the user, and the obtained information / signals can be stored in the memory unit (130). The communication unit (110) converts the information / signals stored in the memory into wireless signals, and can directly transmit the converted wireless signals to other wireless devices or to a base station. In addition, the communication unit (110) can receive wireless signals from other wireless devices or base stations, and then restore the received wireless signals to the original information / signals. The restored information / signals can be stored in the memory unit (130) and then output in various forms (e.g., text, voice, image, video, haptic) through the input / output unit (140c).

[0302] FIG. 19 illustrates a vehicle or autonomous vehicle according to one embodiment of the present disclosure. The vehicle or autonomous vehicle may be implemented as a mobile robot, a car, a train, a manned / unmanned aerial vehicle (AV), a ship, etc. The embodiment of FIG. 19 may be combined with various embodiments of the present disclosure, and some descriptions, functions, procedures, proposals, methods, and / or operations of the embodiments may be omitted.

[0303] Referring to FIG. 19, 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 a part of the communication unit (110). Blocks 110 / 130 / 140a to 140d correspond to blocks 110 / 130 / 140 of FIG. 17, respectively.

[0304] 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, road side units, etc.), and servers. The control unit (120) can control elements of the vehicle or autonomous vehicle (100) to perform various operations. The control unit (120) can include an ECU (Electronic Control Unit). The drive unit (140a) can drive the vehicle or autonomous vehicle (100) on the ground. The drive unit (140a) can include an engine, a motor, a power train, wheels, brakes, a steering device, etc. The power supply unit (140b) supplies power to the vehicle or autonomous vehicle (100) and can include a wired / wireless charging circuit, a battery, 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 incline sensor, a weight detection sensor, a heading sensor, a position module, a vehicle forward / backward 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 a technology for maintaining a driving lane, a technology for automatically controlling speed such as adaptive cruise control, a technology for automatically driving along a set path, a technology for automatically setting a path and driving when a destination is set, etc.

[0305] 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 route and driving plan based on the acquired data. The control unit (120) can control the drive unit (140a) so that the vehicle or autonomous vehicle (100) moves along the autonomous driving route according to the driving plan (e.g., speed / direction control). During autonomous driving, the communication unit (110) can irregularly / periodically acquire the latest traffic information data from an external server and can acquire surrounding traffic information data from surrounding vehicles. In addition, 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 route and driving plan based on newly acquired data / information. The communication unit (110) can transmit information regarding the vehicle location, autonomous driving route, driving plan, etc. to the external server. External servers can predict traffic information data in advance using AI technology or other technologies based on information collected from vehicles or autonomous vehicles, and provide the predicted traffic information data to the vehicles or autonomous vehicles.

[0306] The claims set forth in this specification may be combined in various ways. For example, the technical features of the method claims of this specification may be combined and implemented as a device, and the technical features of the device claims of this specification may be combined and implemented as a method. Furthermore, the technical features of the method claims and the technical features of the device claims of this specification may be combined and implemented as a device, and the technical features of the method claims and the technical features of the device claims of this specification may be combined and implemented as a method.

Claims

1. In the method, A step for a first device to obtain configuration information related to a first carrier; and A step of obtaining information related to channel congestion of the first carrier; including: A method in which whether to include the first carrier in the candidate carrier is based on the channel congestion of the first carrier and the value of a discontinuous transmission (DTX) counter associated with the first carrier.

2. In paragraph 1, A method wherein the first carrier is included in the candidate carriers based on a value of a DTX counter associated with the first carrier being greater than or equal to 1 and less than a DTX threshold.

3. In paragraph 1, A method wherein the first carrier is included in the candidate carriers based on (i) a channel congestion of the first carrier being greater than or equal to a threshold value, and (ii) a value of a DTX counter associated with the first carrier being greater than or equal to 1 and less than a DTX threshold value.

4. In paragraph 3, A method wherein, among one or more carriers included in the candidate carriers, the first carrier is selected as a carrier for SL (sidelink) RLF (radio link failure) detection based on HARQ (hybrid automatic repeat request).

5. In paragraph 4, A method wherein, among at least one carrier selected as a carrier for the HARQ-based SL RLF detection, the channel congestion of the first carrier is higher than the channel congestion of carriers other than the first carrier.

6. In paragraph 1, Whether to include the first carrier in the candidate carriers is performed based on the second carrier selection triggered after the first carrier selection, and A method in which, based on the first carrier being selected as a carrier for HARQ-based SL RLF detection in the first carrier selection, the value of the DTX counter associated with the first carrier is increased from the time of the first carrier selection.

7. In paragraph 6, Further comprising a step of transmitting a physical shared channel to a second device based on the first carrier; A method in which the value of the DTX counter associated with the first carrier is increased based on the absence of reception of a physical feedback channel associated with transmission of the physical shared channel from the second device.

8. In paragraph 7, A method wherein the value of the DTX counter associated with the first carrier does not reach the DTX threshold until the second carrier selection is triggered.

9. In paragraph 1, A method in which the first carrier associated with the channel congestion greater than or equal to a threshold is not excluded from the candidate carriers based on the value of the DTX counter associated with the first carrier being greater than or equal to 1 and less than the DTX threshold.

10. In paragraph 1, A method wherein the value of the DTX counter associated with the first carrier is greater than or equal to 1 and less than the DTX threshold, and is not initialized based on the channel congestion of the first carrier being greater than the threshold.

11. In paragraph 1, A method wherein the resource pool associated with the first carrier is a resource pool in which a physical feedback channel is established.

12. In paragraph 1, A method in which the channel congestion of the first carrier is obtained based on the number of sub-channels associated with a received signal strength indicator (RSSI) greater than or equal to a threshold value among a plurality of sub-channels included in the first carrier.

13. In paragraph 1, A method wherein the first carrier is not included in the candidate carriers based on (i) a channel congestion of the first carrier being greater than or equal to a threshold, and (ii) a value of a DTX counter associated with the first carrier reaching a DTX threshold.

14. In the first device, At least one transmitter / receiver; at least one processor; and At least one memory connected to said at least one processor and storing instructions, said instructions being executed by said at least one processor, wherein said first device causes: Obtain configuration information related to the first carrier; and Obtain information related to channel congestion of the first carrier, A first device, wherein whether to include the first carrier in the candidate carrier is based on the channel congestion of the first carrier and the value of a discontinuous transmission (DTX) counter associated with the first carrier.

15. In a processing device set to control the first device, at least one processor; and At least one memory connected to said at least one processor and storing instructions, said instructions being executed by said at least one processor, wherein said first device causes: Obtain configuration information related to the first carrier; and Obtain information related to channel congestion of the first carrier, A processing device, wherein whether to include the first carrier in the candidate carrier is based on the channel congestion of the first carrier and the value of a discontinuous transmission (DTX) counter associated with the first carrier.

16. A non-transitory computer-readable storage medium that records commands, The above commands, when executed, cause the first device to: Obtain configuration information related to the first carrier; and Obtain information related to channel congestion of the first carrier, A non-transitory computer-readable storage medium, wherein whether to include the first carrier in the candidate carrier is based on the channel congestion of the first carrier and the value of a discontinuous transmission (DTX) counter associated with the first carrier.

17. In the method, A step for a second device to obtain configuration information related to a first carrier; and A step of monitoring a physical shared channel based on the setting information related to the first carrier; including: A method wherein the first carrier is a carrier selected for HARQ (hybrid automatic repeat request)-based SL (sidelink) RLF (radio link failure) detection based on the channel congestion of the first carrier and the value of a DTX (discontinuous transmission) counter associated with the first carrier.

18. In the second device, At least one transmitter / receiver; at least one processor; and At least one memory connected to said at least one processor and storing instructions, said instructions being executed by said at least one processor, wherein said second device causes: Obtain configuration information related to the first carrier; and Based on the configuration information related to the first carrier, the physical shared channel is monitored. A second device, wherein the first carrier is a carrier selected for HARQ (hybrid automatic repeat request)-based SL (sidelink) RLF (radio link failure) detection based on the channel congestion of the first carrier and the value of a DTX (discontinuous transmission) counter associated with the first carrier.

19. In a processing device set to control a second device, at least one processor; and At least one memory connected to said at least one processor and storing instructions, said instructions being executed by said at least one processor, wherein said second device causes: Obtain configuration information related to the first carrier; and Based on the configuration information related to the first carrier, the physical shared channel is monitored. A processing device, wherein the first carrier is a carrier selected for HARQ (hybrid automatic repeat request)-based SL (sidelink) RLF (radio link failure) detection based on the channel congestion of the first carrier and the value of a DTX (discontinuous transmission) counter associated with the first carrier.

20. A non-transitory computer-readable storage medium that records commands, The above commands, when executed, cause the second device to: Obtain configuration information related to the first carrier; and Based on the configuration information related to the first carrier, the physical shared channel is monitored. A non-transitory computer-readable storage medium, wherein the first carrier is a carrier selected for HARQ (hybrid automatic repeat request)-based SL (sidelink) RLF (radio link failure) detection based on a channel congestion of the first carrier and a value of a DTX (discontinuous transmission) counter associated with the first carrier.

Images