Patent Publication Number: US-2022217740-A1

Title: Method and apparatus for performing drx operation based on resource allocation information in nr v2x

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Pursuant to 35 U.S.C. § 119, this application claims the benefit of Korean Patent Application No. 10-2021-0001029 filed on Jan. 5, 2021, U.S. Provisional Applications No. 63/137,676 filed on Jan. 14, 2021, No. 63/134,150 filed on Jan. 5, 2021, and No. 63/137,722 filed on Jan. 14, 2021, the contents of which are all hereby incorporated by reference herein in their entirety. 
    
    
     BACKGROUND OF THE DISCLOSURE 
     Field of the Disclosure 
     This disclosure relates to a wireless communication system. 
     Related Art 
     Sidelink (SL) communication is a communication scheme in which a direct link is established between User Equipments (UEs) and the UEs exchange voice and data directly with each other without intervention of an evolved Node B (eNB). SL communication is under consideration as a solution to the overhead of an eNB caused by rapidly increasing data traffic. Vehicle-to-everything (V2X) refers to a communication technology through which a vehicle exchanges information with another vehicle, a pedestrian, an object having an infrastructure (or infra) established therein, and so on. The V2X may be divided into 4 types, such as vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), vehicle-to-network (V2N), and vehicle-to-pedestrian (V2P). The V2X communication may be provided via a PC5 interface and/or Uu interface. 
     Meanwhile, as a wider range of communication devices require larger communication capacities, the need for mobile broadband communication that is more enhanced than the existing Radio Access Technology (RAT) is rising. Accordingly, discussions are made on services and user equipment (UE) that are sensitive to reliability and latency. And, a next generation radio access technology that is based on the enhanced mobile broadband communication, massive Machine Type Communication (MTC), Ultra-Reliable and Low Latency Communication (URLLC), and so on, may be referred to as a new radio access technology (RAT) or new radio (NR). Herein, the NR may also support vehicle-to-everything (V2X) communication. 
     SUMMARY OF THE DISCLOSURE 
     Technical Objects 
     Meanwhile, if an RX UE supporting a SL DRX operation receives a SCI (e.g., the SCI including reservation transmission scheduling information for PSSCH (i.e., SL data) reception) transmitted by a TX UE, the RX UE may maintain an active state until the RX UE receives all PSCCHs/PSSCHs (e.g., up to three PSSCHs) transmitted by the TX UE using the reserved transmission resource(s). Thereby, the RX UE may monitor (or receive) the PSCCHs/PSSCHs transmitted by the TX UE. That is, the RX UE may be in an active state in a first time interval between a first resource and a second resource on which transmission is not performed by the TX UE, and the RX UE may be in an active state in a second time interval between the second resource and a third resource in which transmission is not performed by the TX UE. In other words, even if the RX UE which has decoded the SCI transmitted by the TX UE knows/determines that transmission is not performed by the TX UE (i) in the first time interval between the first resource and the second resource and/or (ii) in the second time interval between the second resource and the third resource, the RX UE may be in an active state in the first time interval and/or in the second time interval, unnecessarily. This may cause unnecessary power consumption of the RX UE. 
     Meanwhile, according to the conventional NR V2X release 16 technology, only if the interval between the previous transmission and the next transmission (e.g., retransmission) of the TX UE is within 32 slots, the TX UE can reserve chained transmission resources through a plurality of SCIs. If the slot interval between the previous transmission resource and the next transmission resource (e.g., retransmission resource) may be greater than 32 slots, the TX UE cannot include resource reservation information for the next transmission in a SCI. That is, if the RX UE receives the SCI which does not include resource reservation information for the next transmission, the RX UE may determine/consider transmission on the corresponding resource as the last transmission, and the RX UE may transition to a sleep mode during the remaining SL inactive time period. In this case, the RX UE may not receive the next transmission transmitted by the TX UE. 
     Technical Solutions 
     In one embodiment, provided is a method for performing wireless communication by a first device. The method may comprise: obtaining a sidelink (SL) discontinuous reception (DRX) configuration including information related to a timer for an active time and information related to a hybrid automatic repeat request (HARQ) round trip time (RTT) timer; starting the timer for the active time; receiving, from a second device through a physical sidelink control channel (PSCCH) based on a first SL resource, a first sidelink control information (SCI) for scheduling of a physical sidelink shared channel (PSSCH) and a second SCI; and receiving, from the second device through the PSSCH based on the first SL resource, the second SCI and data, wherein, based on resource allocation information for a second SL resource being included in the first SCI, the first device does not monitor retransmission of the data from the second device in a time domain between the first SL resource and the second SL resource, and wherein, based on the resource allocation information for the second SL resource not being included in the first SCI, the HARQ RTT timer included in the SL DRX configuration is started by the first device. 
     In one embodiment, provided is a first device configured to perform wireless communication. The first device may comprise: one or more memories storing instructions; one or more transceivers; and one or more processors connected to the one or more memories and the one or more transceivers. For example, the one or more processors may execute the instructions to: obtain a sidelink (SL) discontinuous reception (DRX) configuration including information related to a timer for an active time and information related to a hybrid automatic repeat request (HARQ) round trip time (RTT) timer; start the timer for the active time; receive, from a second device through a physical sidelink control channel (PSCCH) based on a first SL resource, a first sidelink control information (SCI) for scheduling of a physical sidelink shared channel (PSSCH) and a second SCI; and receive, from the second device through the PSSCH based on the first SL resource, the second SCI and data, wherein, based on resource allocation information for a second SL resource being included in the first SCI, the first device does not monitor retransmission of the data from the second device in a time domain between the first SL resource and the second SL resource, and wherein, based on the resource allocation information for the second SL resource not being included in the first SCI, the HARQ RTT timer included in the SL DRX configuration is started by the first device. 
     Effects of the Disclosure 
     The power saving gain of the UE can be maximized and the reliability of SL communication can be secured. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a structure of an NR system, based on an embodiment of the present disclosure. 
         FIG. 2  shows a radio protocol architecture, based on an embodiment of the present disclosure. 
         FIG. 3  shows a structure of a radio frame of an NR, based on an embodiment of the present disclosure. 
         FIG. 4  shows a structure of a slot of an NR frame, based on an embodiment of the present disclosure. 
         FIG. 5  shows an example of a BWP, based on an embodiment of the present disclosure. 
         FIG. 6  shows a procedure of performing V2X or SL communication by a UE based on a transmission mode, based on an embodiment of the present disclosure. 
         FIG. 7  shows three cast types, based on an embodiment of the present disclosure. 
         FIG. 8  is a drawing for explaining a problem according to the prior art. 
         FIG. 9  is a drawing for explaining a problem according to the prior art. 
         FIG. 10  shows a method for a UE to transmit/receive data based on resource reservation information included in a SCI, based on an embodiment of the present disclosure. 
         FIG. 11  shows a procedure for an RX UE to perform an SL DRX operation based on resource reservation information included in a SCI, based on an embodiment of the present disclosure. 
         FIG. 12  shows a method for a UE to transmit/receive data based on resource reservation information included in a SCI, based on an embodiment of the present disclosure. 
         FIG. 13  shows a procedure for an RX UE to perform an SL DRX operation based on resource reservation information included in a SCI, based on an embodiment of the present disclosure. 
         FIG. 14  shows a procedure for aligning SL DRX configurations between a TX UE and an RX UE, based on an embodiment of the present disclosure. 
         FIG. 15  shows an example of alignment of SL DRX configurations between SL DRX of a UE  1  and SL DRX of a UE  2 , based on an embodiment of the present disclosure. 
         FIG. 16  shows a method for a first device to perform wireless communication, based on an embodiment of the present disclosure. 
         FIG. 17  shows a method for a second device to perform wireless communication, based on an embodiment of the present disclosure. 
         FIG. 18  shows a communication system  1 , based on an embodiment of the present disclosure. 
         FIG. 19  shows wireless devices, based on an embodiment of the present disclosure. 
         FIG. 20  shows a signal process circuit for a transmission signal, based on an embodiment of the present disclosure. 
         FIG. 21  shows another example of a wireless device, based on an embodiment of the present disclosure. 
         FIG. 22  shows a hand-held device, based on an embodiment of the present disclosure. 
         FIG. 23  shows a vehicle or an autonomous vehicle, based on an embodiment of the present disclosure. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     In the present disclosure, “A or B” may mean “only A”, “only B” or “both A and B.” In other words, in the present disclosure, “A or B” may be interpreted as “A and/or B”. For example, in the present disclosure, “A, B, or C” may mean “only A”, “only B”, “only C”, or “any combination of A, B, C”. 
     A slash (/) or comma used in the present disclosure 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”. 
     In the present disclosure, “at least one of A and B” may mean “only A”, “only B”, or “both A and B”. In addition, in the present disclosure, the expression “at least one of A or B” or “at least one of A and/or B” may be interpreted as “at least one of A and B”. 
     In addition, in the present disclosure, “at least one of A, B, and C” may mean “only A”, “only B”, “only C”, or “any combination of A, B, and C”. In addition, “at least one of A, B, or C” or “at least one of A, B, and/or C” may mean “at least one of A, B, and C”. 
     In addition, a parenthesis used in the present disclosure may mean “for example”. Specifically, when indicated as “control information (PDCCH)”, it may mean that “PDCCH” is proposed as an example of the “control information”. In other words, the “control information” of the present disclosure is not limited to “PDCCH”, and “PDCCH” may be proposed as an example of the “control information”. In addition, when indicated as “control information (i.e., PDCCH)”, it may also mean that “PDCCH” is proposed as an example of the “control information”. 
     In the following description, ‘when, if, or in case of’ may be replaced with ‘based on’. 
     A technical feature described individually in one figure in the present disclosure may be individually implemented, or may be simultaneously implemented. 
     In the present disclosure, a higher layer parameter may be a parameter which is configured, pre-configured or pre-defined for a UE. For example, a base station or a network may transmit the higher layer parameter to the UE. For example, the higher layer parameter may be transmitted through radio resource control (RRC) signaling or medium access control (MAC) signaling. 
     The technology described below may be used in various wireless communication systems such as code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), single carrier frequency division multiple access (SC-FDMA), and so on. The CDMA may be implemented with a radio technology, such as universal terrestrial radio access (UTRA) or CDMA-2000. The TDMA may be implemented with a radio technology, such as global system for mobile communications (GSM)/general packet ratio service (GPRS)/enhanced data rate for GSM evolution (EDGE). The OFDMA may be implemented with a radio technology, such as institute of electrical and electronics engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, evolved UTRA (E-UTRA), and so on. IEEE 802.16m is an evolved version of IEEE 802.16e and provides backward compatibility with a system based on the IEEE 802.16e. The UTRA is part of a universal mobile telecommunication system (UMTS). 3rd generation partnership project (3GPP) long term evolution (LTE) is part of an evolved UMTS (E-UMTS) using the E-UTRA. The 3GPP LTE uses the OFDMA in a downlink and uses the SC-FDMA in an uplink. LTE-advanced (LTE-A) is an evolution of the LTE. 
     5G NR is a successive technology of LTE-A corresponding to a new Clean-slate type mobile communication system having the characteristics of high performance, low latency, high availability, and so on. 5G NR may use resources of all spectrum available for usage including low frequency bands of less than 1 GHz, middle frequency bands ranging from 1 GHz to 10 GHz, high frequency (millimeter waves) of 24 GHz or more, and so on. 
     For clarity in the description, the following description will mostly focus on LTE-A or 5G NR. However, technical features according to an embodiment of the present disclosure will not be limited only to this. 
       FIG. 1  shows a structure of an NR system, based on an embodiment of the present disclosure. The embodiment of  FIG. 1  may be combined with various embodiments of the present disclosure. 
     Referring to  FIG. 1 , a next generation-radio access network (NG-RAN) may include a BS  20  providing a UE  10  with a user plane and control plane protocol termination. For example, the BS  20  may include a next generation-Node B (gNB) and/or an evolved-NodeB (eNB). For example, the UE  10  may be fixed or mobile and may be referred to as other terms, such as a mobile station (MS), a user terminal (UT), a subscriber station (SS), a mobile terminal (MT), wireless device, and so on. For example, the BS may be referred to as a fixed station which communicates with the UE  10  and may be referred to as other terms, such as a base transceiver system (BTS), an access point (AP), and so on. 
     The embodiment of  FIG. 1  exemplifies a case where only the gNB is included. The BSs  20  may be connected to one another via Xn interface. The BS  20  may be connected to one another via 5th generation (5G) core network (5GC) and NG interface. More specifically, the BSs  20  may be connected to an access and mobility management function (AMF)  30  via NG-C interface, and may be connected to a user plane function (UPF)  30  via NG-U interface. 
     Layers of a radio interface protocol between the UE and the network can be classified into a first layer (layer 1, L1), a second layer (layer 2, L2), and a third layer (layer 3, L3) based on the lower three layers of the open system interconnection (OSI) model that is well-known in the communication system. Among them, a physical (PHY) layer belonging to the first layer provides an information transfer service by using a physical channel, and a radio resource control (RRC) layer belonging to the third layer serves to control a radio resource between the UE and the network. For this, the RRC layer exchanges an RRC message between the UE and the BS. 
       FIG. 2  shows a radio protocol architecture, based on an embodiment of the present disclosure. The embodiment of  FIG. 2  may be combined with various embodiments of the present disclosure. Specifically, (a) of  FIG. 2  shows a radio protocol stack of a user plane for Uu communication, and (b) of  FIG. 2  shows a radio protocol stack of a control plane for Uu communication. (c) of  FIG. 2  shows a radio protocol stack of a user plane for SL communication, and (d) of  FIG. 2  shows a radio protocol stack of a control plane for SL communication. 
     Referring to  FIG. 2 , a physical layer provides an upper layer with an information transfer service through a physical channel. The physical layer is connected to a medium access control (MAC) layer which is an upper layer of the physical layer through a transport channel. Data is transferred between the MAC layer and the physical layer through the transport channel. The transport channel is classified according to how and with what characteristics data is transmitted through a radio interface. 
     Between different physical layers, i.e., a physical layer of a transmitter and a physical layer of a receiver, data are transferred through the physical channel. The physical channel is modulated using an orthogonal frequency division multiplexing (OFDM) scheme, and utilizes time and frequency as a radio resource. 
     The MAC layer provides services to a radio link control (RLC) layer, which is a higher layer of the MAC layer, via a logical channel. The MAC layer provides a function of mapping multiple logical channels to multiple transport channels. The MAC layer also provides a function of logical channel multiplexing by mapping multiple logical channels to a single transport channel. The MAC layer provides data transfer services over logical channels. 
     The RLC layer performs concatenation, segmentation, and reassembly of Radio Link Control Service Data Unit (RLC SDU). In order to ensure diverse quality of service (QoS) required by a radio bearer (RB), the RLC layer provides three types of operation modes, i.e., a transparent mode (TM), an unacknowledged mode (UM), and an acknowledged mode (AM). An AM RLC provides error correction through an automatic repeat request (ARQ). 
     A radio resource control (RRC) layer is defined only in the control plane. The RRC layer serves to control the logical channel, the transport channel, and the physical channel in association with configuration, reconfiguration and release of RBs. The RB is a logical path provided by the first layer (i.e., the physical layer or the PHY layer) and the second layer (i.e., a MAC layer, an RLC layer, a packet data convergence protocol (PDCP) layer, and a service data adaptation protocol (SDAP) layer) for data delivery between the UE and the network. 
     Functions of a packet data convergence protocol (PDCP) layer in the user plane include user data delivery, header compression, and ciphering. Functions of a PDCP layer in the control plane include control-plane data delivery and ciphering/integrity protection. 
     A service data adaptation protocol (SDAP) layer is defined only in a user plane. The SDAP layer performs mapping between a Quality of Service (QoS) flow and a data radio bearer (DRB) and QoS flow ID (QFI) marking in both DL and UL packets. 
     The configuration of the RB implies a process for specifying a radio protocol layer and channel properties to provide a particular service and for determining respective detailed parameters and operations. The RB can be classified into two types, i.e., a signaling RB (SRB) and a data RB (DRB). The SRB is used as a path for transmitting an RRC message in the control plane. The DRB is used as a path for transmitting user data in the user plane. 
     When an RRC connection is established between an RRC layer of the UE and an RRC layer of the E-UTRAN, the UE is in an RRC_CONNECTED state, and, otherwise, the UE may be in an RRC_IDLE state. In case of the NR, an RRC_INACTIVE state is additionally defined, and a UE being in the RRC_INACTIVE state may maintain its connection with a core network whereas its connection with the BS is released. 
     Data is transmitted from the network to the UE through a downlink transport channel. Examples of the downlink transport channel include a broadcast channel (BCH) for transmitting system information and a downlink-shared channel (SCH) for transmitting user traffic or control messages. Traffic of downlink multicast or broadcast services or the control messages can be transmitted on the downlink-SCH or an additional downlink multicast channel (MCH). Data is transmitted from the UE to the network through an uplink transport channel. Examples of the uplink transport channel include a random access channel (RACH) for transmitting an initial control message and an uplink SCH for transmitting user traffic or control messages. 
     Examples of logical channels belonging to a higher channel of the transport channel and mapped onto the transport channels include a broadcast channel (BCCH), a paging control channel (PCCH), a common control channel (CCCH), a multicast control channel (MCCH), a multicast traffic channel (MTCH), etc. 
       FIG. 3  shows a structure of a radio frame of an NR, based on an embodiment of the present disclosure. The embodiment of  FIG. 3  may be combined with various embodiments of the present disclosure. 
     Referring to  FIG. 3 , in the NR, a radio frame may be used for performing uplink and downlink transmission. A radio frame has a length of 10 ms and may be defined to be configured of two half-frames (HFs). A half-frame may include five 1 ms subframes (SFs). A subframe (SF) may be divided into one or more slots, and the number of slots within a subframe may be determined based on subcarrier spacing (SCS). Each slot may include 12 or 14 OFDM(A) symbols according to a cyclic prefix (CP). 
     In case of using a normal CP, each slot may include 14 symbols. In case of using an extended CP, each slot may include 12 symbols. Herein, a symbol may include an OFDM symbol (or CP-OFDM symbol) and a Single Carrier-FDMA (SC-FDMA) symbol (or Discrete Fourier Transform-spread-OFDM (DFT-s-OFDM) symbol). 
     Table 1 shown below represents an example of a number of symbols per slot (N slot   symb ), a number slots per frame (N frame,μ   slot ), and a number of slots per subframe (N subframe   slot ) based on an SCS configuration (u), in a case where a normal CP is used. 
     
       
         
           
               
               
               
               
               
             
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 SCS (15*2 u ) 
                 N slot   symb   
                 N frame, u   slot   
                 N subframe, u   slot   
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
            
               
                   
                 15 KHz (u = 0) 
                 14 
                 10 
                 1 
               
               
                   
                 30 KHz (u = 1) 
                 14 
                 20 
                 2 
               
               
                   
                 60 KHz (u = 2) 
                 14 
                 40 
                 4 
               
               
                   
                 120 KHz (u = 3)  
                 14 
                 80 
                 8 
               
               
                   
                 240 KHz (u = 4)  
                 14 
                 160 
                 16 
               
               
                   
                   
               
            
           
         
       
     
     Table 2 shows an example of a number of symbols per slot, a number of slots per frame, and a number of slots per subframe based on the SCS, in a case where an extended CP is used. 
     
       
         
           
               
               
               
               
               
             
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                 SCS (15*2 u ) 
                 N slot   symb   
                 N frame, u   slot   
                 N subframe, u   slot   
               
               
                   
                   
               
             
            
               
                   
                 60 KHz (u = 2) 
                 12 
                 40 
                 4 
               
               
                   
                   
               
            
           
         
       
     
     In an NR system, OFDM(A) numerologies (e.g., SCS, CP length, and so on) between multiple cells being integrate to one UE may be differently configured. Accordingly, a (absolute time) duration (or section) of a time resource (e.g., subframe, slot or TTI) (collectively referred to as a time unit (TU) for simplicity) being configured of the same number of symbols may be differently configured in the integrated cells. 
     In the NR, multiple numerologies or SCSs for supporting diverse 5G services may be supported. For example, in case an SCS is 15 kHz, a wide area of the conventional cellular bands may be supported, and, in case an SCS is 30 kHz/60 kHz a dense-urban, lower latency, wider carrier bandwidth may be supported. In case the SCS is 60 kHz or higher, a bandwidth that is greater than 24.25 GHz may be used in order to overcome phase noise. 
     An NR frequency band may be defined as two different types of frequency ranges. The two different types of frequency ranges may be FR1 and FR2. The values of the frequency ranges may be changed (or varied), and, for example, the two different types of frequency ranges may be as shown below in Table 3. Among the frequency ranges that are used in an NR system, FR1 may mean a “sub 6 GHz range”, and FR2 may mean an “above 6 GHz range” and may also be referred to as a millimeter wave (mmW). 
     
       
         
           
               
               
               
             
               
                 TABLE 3 
               
               
                   
               
               
                 Frequency Range 
                 Corresponding 
                   
               
               
                 designation 
                 frequency range 
                 Subcarrier Spacing (SCS) 
               
               
                   
               
             
            
               
                 FR1 
                  450 MHz-6000 MHz 
                  15, 30, 60 kHz 
               
               
                 FR2 
                 24250 MHz-52600 MHz 
                 60, 120, 240 kHz 
               
               
                   
               
            
           
         
       
     
     As described above, the values of the frequency ranges in the NR system may be changed (or varied). For example, as shown below in Table 4, FR1 may include a band within a range of 410 MHz to 7125 MHz. More specifically, FR1 may include a frequency band of 6 GHz (or 5850, 5900, 5925 MHz, and so on) and higher. For example, a frequency band of 6 GHz (or 5850, 5900, 5925 MHz, and so on) and higher being included in FR1 may include an unlicensed band. The unlicensed band may be used for diverse purposes, e.g., the unlicensed band for vehicle-specific communication (e.g., automated driving). 
     
       
         
           
               
               
               
             
               
                 TABLE 4 
               
               
                   
               
               
                 Frequency Range 
                 Corresponding 
                   
               
               
                 designation 
                 frequency range 
                 Subcarrier Spacing (SCS) 
               
               
                   
               
             
            
               
                 FR1 
                  410 MHz-7125 MHz 
                  15, 30, 60 kHz 
               
               
                 FR2 
                 24250 MHz-52600 MHz 
                 60, 120, 240 kHz 
               
               
                   
               
            
           
         
       
     
       FIG. 4  shows a structure of a slot of an NR frame, based on an embodiment of the present disclosure. The embodiment of  FIG. 4  may be combined with various embodiments of the present disclosure. 
     Referring to  FIG. 4 , a slot includes a plurality of symbols in a time domain. For example, in case of a normal CP, one slot may include 14 symbols. However, in case of an extended CP, one slot may include 12 symbols. Alternatively, in case of a normal CP, one slot may include 7 symbols. However, in case of an extended CP, one slot may include 6 symbols. 
     A carrier includes a plurality of subcarriers in a frequency domain. A Resource Block (RB) may be defined as a plurality of consecutive subcarriers (e.g.,  12  subcarriers) in the frequency domain. A Bandwidth Part (BWP) may be defined as a plurality of consecutive (Physical) Resource Blocks ((P)RBs) in the frequency domain, and the BWP may correspond to one numerology (e.g., SCS, CP length, and so on). A carrier may include a maximum of N number BWPs (e.g.,  5  BWPs). Data communication may be performed via an activated BWP. Each element may be referred to as a Resource Element (RE) within a resource grid and one complex symbol may be mapped to each element. 
     Hereinafter, a bandwidth part (BWP) and a carrier will be described. 
     The BWP may be a set of consecutive physical resource blocks (PRBs) in a given numerology. The PRB may be selected from consecutive sub-sets of common resource blocks (CRBs) for the given numerology on a given carrier 
     For example, the BWP may be at least any one of an active BWP, an initial BWP, and/or a default BWP. For example, the UE may not monitor downlink radio link quality in a DL BWP other than an active DL BWP on a primary cell (PCell). For example, the UE may not receive PDCCH, physical downlink shared channel (PDSCH), or channel state information—reference signal (CSI-RS) (excluding RRM) outside the active DL BWP. For example, the UE may not trigger a channel state information (CSI) report for the inactive DL BWP. For example, the UE may not transmit physical uplink control channel (PUCCH) or physical uplink shared channel (PUSCH) outside an active UL BWP. For example, in a downlink case, the initial BWP may be given as a consecutive RB set for a remaining minimum system information (RMSI) control resource set (CORESET) (configured by physical broadcast channel (PBCH)). For example, in an uplink case, the initial BWP may be given by system information block (SIB) for a random access procedure. For example, the default BWP may be configured by a higher layer. For example, an initial value of the default BWP may be an initial DL BWP. For energy saving, if the UE fails to detect downlink control information (DCI) during a specific period, the UE may switch the active BWP of the UE to the default BWP. 
     Meanwhile, the BWP may be defined for SL. The same SL BWP may be used in transmission and reception. For example, a transmitting UE may transmit a SL channel or a SL signal on a specific BWP, and a receiving UE may receive the SL channel or the SL signal on the specific BWP. In a licensed carrier, the SL BWP may be defined separately from a Uu BWP, and the SL BWP may have configuration signaling separate from the Uu BWP. For example, the UE may receive a configuration for the SL BWP from the BS/network. For example, the UE may receive a configuration for the Uu BWP from the BS/network. The SL BWP may be (pre-)configured in a carrier with respect to an out-of-coverage NR V2X UE and an RRC_IDLE UE. For the UE in the RRC_CONNECTED mode, at least one SL BWP may be activated in the carrier. 
       FIG. 5  shows an example of a BWP, based on an embodiment of the present disclosure. The embodiment of  FIG. 5  may be combined with various embodiments of the present disclosure. It is assumed in the embodiment of  FIG. 5  that the number of BWPs is 3. 
     Referring to  FIG. 5 , a common resource block (CRB) may be a carrier resource block numbered from one end of a carrier band to the other end thereof. In addition, the PRB may be a resource block numbered within each BWP. A point A may indicate a common reference point for a resource block grid. 
     The BWP may be configured by a point A, an offset N start   BWP  from the point A, and a bandwidth N size   BWP . For example, the point A may be an external reference point of a PRB of a carrier in which a subcarrier  0  of all numerologies (e.g., all numerologies supported by a network on that carrier) is aligned. For example, the offset may be a PRB interval between a lowest subcarrier and the point A in a given numerology. For example, the bandwidth may be the number of PRBs in the given numerology. 
     Hereinafter, V2X or SL communication will be described. 
     A sidelink synchronization signal (SLSS) may include a primary sidelink synchronization signal (PSSS) and a secondary sidelink synchronization signal (SSSS), as a SL-specific sequence. The PSSS may be referred to as a sidelink primary synchronization signal (S-PSS), and the SSSS may be referred to as a sidelink secondary synchronization signal (S-SSS). For example, length-127 M-sequences may be used for the S-PSS, and length-127 gold sequences may be used for the S-SSS. For example, a UE may use the S-PSS for initial signal detection and for synchronization acquisition. For example, the UE may use the S-PSS and the S-SSS for acquisition of detailed synchronization and for detection of a synchronization signal ID. 
     A physical sidelink broadcast channel (PSBCH) may be a (broadcast) channel for transmitting default (system) information which must be first known by the UE before SL signal transmission/reception. For example, the default information may be information related to SLSS, a duplex mode (DM), a time division duplex (TDD) uplink/downlink (UL/DL) configuration, information related to a resource pool, a type of an application related to the SLSS, a subframe offset, broadcast information, or the like. For example, for evaluation of PSBCH performance, in NR V2X, a payload size of the PSBCH may be 56 bits including 24-bit cyclic redundancy check (CRC). 
     The S-PSS, the S-SSS, and the PSBCH may be included in a block format (e.g., SL synchronization signal (SS)/PSBCH block, hereinafter, sidelink-synchronization signal block (S-SSB)) supporting periodical transmission. The S-SSB may have the same numerology (i.e., SCS and CP length) as a physical sidelink control channel (PSCCH)/physical sidelink shared channel (PSSCH) in a carrier, and a transmission bandwidth may exist within a (pre-)configured sidelink (SL) BWP. For example, the S-SSB may have a bandwidth of 11 resource blocks (RBs). For example, the PSBCH may exist across 11 RBs. In addition, a frequency position of the S-SSB may be (pre-)configured. Accordingly, the UE does not have to perform hypothesis detection at frequency to discover the S-SSB in the carrier. 
       FIG. 6  shows a procedure of performing V2X or SL communication by a UE based on a transmission mode, based on an embodiment of the present disclosure. The embodiment of  FIG. 6  may be combined with various embodiments of the present disclosure. In various embodiments of the present disclosure, the transmission mode may be called a mode or a resource allocation mode. Hereinafter, for convenience of explanation, in LTE, the transmission mode may be called an LTE transmission mode. In NR, the transmission mode may be called an NR resource allocation mode. 
     For example, (a) of  FIG. 6  shows a UE operation related to an LTE transmission mode 1 or an LTE transmission mode 3. Alternatively, for example, (a) of  FIG. 6  shows a UE operation related to an NR resource allocation mode 1. For example, the LTE transmission mode 1 may be applied to general SL communication, and the LTE transmission mode 3 may be applied to V2X communication. 
     For example, (b) of  FIG. 6  shows a UE operation related to an LTE transmission mode 2 or an LTE transmission mode 4. Alternatively, for example, (b) of  FIG. 6  shows a UE operation related to an NR resource allocation mode 2. 
     Referring to (a) of  FIG. 6 , in the LTE transmission mode 1, the LTE transmission mode 3, or the NR resource allocation mode 1, a base station may schedule SL resource(s) to be used by a UE for SL transmission. For example, in step S 600 , a base station may transmit information related to SL resource(s) and/or information related to UL resource(s) to a first UE. For example, the UL resource(s) may include PUCCH resource(s) and/or PUSCH resource(s). For example, the UL resource(s) may be resource(s) for reporting SL HARQ feedback to the base station. 
     For example, the first UE may receive information related to dynamic grant (DG) resource(s) and/or information related to configured grant (CG) resource(s) from the base station. For example, the CG resource(s) may include CG type 1 resource(s) or CG type 2 resource(s). In the present disclosure, the DG resource(s) may be resource(s) configured/allocated by the base station to the first UE through a downlink control information (DCI). In the present disclosure, the CG resource(s) may be (periodic) resource(s) configured/allocated by the base station to the first UE through a DCI and/or an RRC message. For example, in the case of the CG type 1 resource(s), the base station may transmit an RRC message including information related to CG resource(s) to the first UE. For example, in the case of the CG type 2 resource(s), the base station may transmit an RRC message including information related to CG resource(s) to the first UE, and the base station may transmit a DCI related to activation or release of the CG resource(s) to the first UE. 
     In step S 610 , the first UE may transmit a PSCCH (e.g., sidelink control information (SCI) or 1 st -stage SCI) to a second UE based on the resource scheduling. In step S 620 , the first UE may transmit a PSSCH (e.g., 2 nd -stage SCI, MAC PDU, data, etc.) related to the PSCCH to the second UE. In step S 630 , the first UE may receive a PSFCH related to the PSCCH/PSSCH from the second UE. For example, HARQ feedback information (e.g., NACK information or ACK information) may be received from the second UE through the PSFCH. In step S 640 , the first UE may transmit/report HARQ feedback information to the base station through the PUCCH or the PUSCH. For example, the HARQ feedback information reported to the base station may be information generated by the first UE based on the HARQ feedback information received from the second UE. For example, the HARQ feedback information reported to the base station may be information generated by the first UE based on a pre-configured rule. For example, the DCI may be a DCI for SL scheduling. For example, a format of the DCI may be a DCI format 3_0 or a DCI format 3_1. 
     Hereinafter, an example of DCI format 3_0 will be described. 
     DCI format 3_0 is used for scheduling of NR PSCCH and NR PSSCH in one cell. 
     The following information is transmitted by means of the DCI format 3_0 with CRC scrambled by SL-RNTI or SL-CS-RNTI:
         Resource pool index—ceiling (log 2  I) bits, where I is the number of resource pools for transmission configured by the higher layer parameter sl-TxPoolScheduling.   Time gap—3 bits determined by higher layer parameter sl-DCI-ToSL-Trans   HARQ process number—4 bits   New data indicator—1 bit   Lowest index of the subchannel allocation to the initial transmission—ceiling (log 2 (N SL   subChannel )) bits   SCI format 1-A fields: frequency resource assignment, time resource assignment   PSFCH-to-HARQ feedback timing indicator—ceiling (log 2  N fb_timing ) bits, where N fb_timing  is the number of entries in the higher layer parameter sl-PSFCH-ToPUCCH.   PUCCH resource indicator—3 bits   Configuration index—0 bit if the UE is not configured to monitor DCI format 3_0 with CRC scrambled by SL-CS-RNTI; otherwise 3 bits. If the UE is configured to monitor DCI format 3_0 with CRC scrambled by SL-CS-RNTI, this field is reserved for DCI format 3_0 with CRC scrambled by SL-RNTI.   Counter sidelink assignment index—2 bits, 2 bits if the UE is configured with pdsch-HARQ-ACK-Codebook=dynamic, 2 bits if the UE is configured with pdsch-HARQ-ACK-Codebook=semi-static   Padding bits, if required       

     Referring to (b) of  FIG. 6 , in the LTE transmission mode 2, the LTE transmission mode 4, or the NR resource allocation mode 2, a UE may determine SL transmission resource(s) within SL resource(s) configured by a base station/network or pre-configured SL resource(s). For example, the configured SL resource(s) or the pre-configured SL resource(s) may be a resource pool. For example, the UE may autonomously select or schedule resource(s) for SL transmission. For example, the UE may perform SL communication by autonomously selecting resource(s) within the configured resource pool. For example, the UE may autonomously select resource(s) within a selection window by performing a sensing procedure and a resource (re)selection procedure. For example, the sensing may be performed in a unit of subchannel(s). For example, in step S 610 , a first UE which has selected resource(s) from a resource pool by itself may transmit a PSCCH (e.g., sidelink control information (SCI) or 1 st -stage SCI) to a second UE by using the resource(s). In step S 620 , the first UE may transmit a PSSCH (e.g., 2 nd -stage SCI, MAC PDU, data, etc.) related to the PSCCH to the second UE. In step S 630 , the first UE may receive a PSFCH related to the PSCCH/PSSCH from the second UE. 
     Referring to (a) or (b) of  FIG. 6 , for example, the first UE may transmit a SCI to the second UE through the PSCCH. Alternatively, for example, the first UE may transmit two consecutive SCIs (e.g., 2-stage SCI) to the second UE through the PSCCH and/or the PSSCH. In this case, the second UE may decode two consecutive SCIs (e.g., 2-stage SCI) to receive the PSSCH from the first UE. In the present disclosure, a SCI transmitted through a PSCCH may be referred to as a 1 st  SCI, a first SCI, a 1 st -stage SCI or a 1 st -stage SCI format, and a SCI transmitted through a PSSCH may be referred to as a 2 nd  SCI, a second SCI, a 2 nd -stage SCI or a 2 nd -stage SCI format. For example, the 1 st -stage SCI format may include a SCI format 1-A, and the 2 nd -stage SCI format may include a SCI format 2-A and/or a SCI format 2-B. 
     Hereinafter, an example of SCI format 1-A will be described. 
     SCI format 1-A is used for the scheduling of PSSCH and 2nd-stage-SCI on PSSCH. 
     The following information is transmitted by means of the SCI format 1-A: 
     Priority—3 bits 
     Frequency resource assignment—ceiling (log 2 (N SL   subChannel (N SL   subChannel +1)/2)) bits when the value of the higher layer parameter sl-MaxNumPerReserve is configured to 2; otherwise ceiling log 2 (N SL   subChannel (N SL   subChannel +1)(2N SL   subChannel +1)/6) bits when the value of the higher layer parameter sl-MaxNumPerReserve is configured to 3 
     Time resource assignment—5 bits when the value of the higher layer parameter sl-MaxNumPerReserve is configured to 2; otherwise 9 bits when the value of the higher layer parameter sl-MaxNumPerReserve is configured to 3 
     Resource reservation period—ceiling (log 2 N rsv_period ) bits, where N rsv_period  is the number of entries in the higher layer parameter sl-ResourceReservePeriodList, if higher layer parameter sl-MultiReserveResource is configured; 0 bit otherwise 
     DMRS pattern—ceiling (log 2  N pattern ) bits, where N pattern  is the number of DMRS patterns configured by higher layer parameter sl-PSSCH-DMRS-TimePatternList 
     2 nd -stage SCI format—2 bits as defined in Table 5 
     Beta_offset indicator—2 bits as provided by higher layer parameter sl-BetaOffsets2 nd  SCI 
     Number of DMRS port—1 bit as defined in Table 6 
     Modulation and coding scheme—5 bits 
     Additional MCS table indicator—1 bit if one MCS table is configured by higher layer parameter sl-Additional-MCS-Table; 2 bits if two MCS tables are configured by higher layer parameter sl-Additional-MCS-Table; 0 bit otherwise 
     PSFCH overhead indication—1 bit if higher layer parameter sl-PSFCH-Period=2 or 4; 0 bit otherwise 
     Reserved—a number of bits as determined by higher layer parameter sl-NumReservedBits, with value set to zero. 
     
       
         
           
               
               
             
               
                 TABLE 5 
               
               
                   
               
               
                 Value of 2nd-stage SCI format field 
                 2nd-stage SCI format 
               
               
                   
               
             
            
               
                 00 
                 SCI format 2-A 
               
               
                 01 
                 SCI format 2-B 
               
               
                 10 
                 Reserved 
               
               
                 11 
                 Reserved 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
               
               
             
               
                   
                 TABLE 6 
               
               
                   
                   
               
               
                   
                 Value of the Number of DMRS port field 
                 Antenna ports 
               
               
                   
                   
               
             
            
               
                   
                 0 
                 1000 
               
               
                   
                 1 
                 1000 and 1001 
               
               
                   
                   
               
            
           
         
       
     
     Hereinafter, an example of SCI format 2-A will be described. 
     SCI format 2-A is used for the decoding of PSSCH, with HARQ operation when HARQ-ACK information includes ACK or NACK, when HARQ-ACK information includes only NACK, or when there is no feedback of HARQ-ACK information. 
     The following information is transmitted by means of the SCI format 2-A:
         HARQ process number—4 bits   New data indicator—1 bit   Redundancy version—2 bits   Source ID—8 bits   Destination ID—16 bits   HARQ feedback enabled/disabled indicator—1 bit   Cast type indicator—2 bits as defined in Table 7   CSI request—1 bit       

     
       
         
           
               
               
             
               
                 TABLE 7 
               
               
                   
               
               
                 Value of Cast 
                   
               
               
                 type indicator 
                 Cast type 
               
               
                   
               
             
            
               
                 00 
                 Broadcast 
               
               
                 01 
                 Groupcast when HARQ-ACK information 
               
               
                   
                 includes ACK or NACK 
               
               
                 10 
                 Unicast 
               
               
                 11 
                 Groupcast when HARQ-ACK information 
               
               
                   
                 includes only NACK 
               
               
                   
               
            
           
         
       
     
     Hereinafter, an example of SCI format 2-B will be described. 
     SCI format 2-B is used for the decoding of PSSCH, with HARQ operation when HARQ-ACK information includes only NACK, or when there is no feedback of HARQ-ACK information. 
     The following information is transmitted by means of the SCI format 2-B:
         HARQ process number—4 bits   New data indicator—1 bit   Redundancy version—2 bits   Source ID—8 bits   Destination ID—16 bits   HARQ feedback enabled/disabled indicator—1 bit   Zone ID—12 bits   Communication range requirement—4 bits determined by higher layer parameter sl-ZoneConfigMCR-Index       

     Referring to (a) or (b) of  FIG. 6 , in step S 630 , the first UE may receive the PSFCH. For example, the first UE and the second UE may determine a PSFCH resource, and the second UE may transmit HARQ feedback to the first UE using the PSFCH resource. 
     Referring to (a) of  FIG. 6 , in step S 640 , the first UE may transmit SL HARQ feedback to the base station through the PUCCH and/or the PUSCH. 
       FIG. 7  shows three cast types, based on an embodiment of the present disclosure. The embodiment of  FIG. 7  may be combined with various embodiments of the present disclosure. Specifically, (a) of  FIG. 7  shows broadcast-type SL communication, (b) of  FIG. 7  shows unicast type-SL communication, and (c) of  FIG. 7  shows groupcast-type SL communication. In case of the unicast-type SL communication, a UE may perform one-to-one communication with respect to another UE. In case of the groupcast-type SL transmission, the UE may perform SL communication with respect to one or more UEs in a group to which the UE belongs. In various embodiments of the present disclosure, SL groupcast communication may be replaced with SL multicast communication, SL one-to-many communication, or the like. 
     Hereinafter, a hybrid automatic repeat request (HARQ) procedure will be described. 
     For example, the SL HARQ feedback may be enabled for unicast. In this case, in a non-code block group (non-CBG) operation, if the receiving UE decodes a PSCCH of which a target is the receiving UE and if the receiving UE successfully decodes a transport block related to the PSCCH, the receiving UE may generate HARQ-ACK. In addition, the receiving UE may transmit the HARQ-ACK to the transmitting UE. Otherwise, if the receiving UE cannot successfully decode the transport block after decoding the PSCCH of which the target is the receiving UE, the receiving UE may generate the HARQ-NACK. In addition, the receiving UE may transmit HARQ-NACK to the transmitting UE. 
     For example, the SL HARQ feedback may be enabled for groupcast. For example, in the non-CBG operation, two HARQ feedback options may be supported for groupcast. 
     (1) Groupcast option 1: After the receiving UE decodes the PSCCH of which the target is the receiving UE, if the receiving UE fails in decoding of a transport block related to the PSCCH, the receiving UE may transmit HARQ-NACK to the transmitting UE through a PSFCH. Otherwise, if the receiving UE decodes the PSCCH of which the target is the receiving UE and if the receiving UE successfully decodes the transport block related to the PSCCH, the receiving UE may not transmit the HARQ-ACK to the transmitting UE. 
     (2) Groupcast option 2: After the receiving UE decodes the PSCCH of which the target is the receiving UE, if the receiving UE fails in decoding of the transport block related to the PSCCH, the receiving UE may transmit HARQ-NACK to the transmitting UE through the PSFCH. In addition, if the receiving UE decodes the PSCCH of which the target is the receiving UE and if the receiving UE successfully decodes the transport block related to the PSCCH, the receiving UE may transmit the HARQ-ACK to the transmitting UE through the PSFCH. 
     For example, if the groupcast option 1 is used in the SL HARQ feedback, all UEs performing groupcast communication may share a PSFCH resource. For example, UEs belonging to the same group may transmit HARQ feedback by using the same PSFCH resource. 
     For example, if the groupcast option 2 is used in the SL HARQ feedback, each UE performing groupcast communication may use a different PSFCH resource for HARQ feedback transmission. For example, UEs belonging to the same group may transmit HARQ feedback by using different PSFCH resources. 
     In the present disclosure, HARQ-ACK may be referred to as ACK, ACK information, or positive-ACK information, and HARQ-NACK may be referred to as NACK, NACK information, or negative-ACK information. 
     Hereinafter, UE procedure for reporting HARQ-ACK on sidelink will be described. 
     A UE can be indicated by an SCI format scheduling a PSSCH reception, in one or more sub-channels from a number of N PSSCH   subch  sub-channels, to transmit a PSFCH with HARQ-ACK information in response to the PSSCH reception. The UE provides HARQ-ACK information that includes ACK or NACK, or only NACK. 
     A UE can be provided, by sl-PSFCH-Period-r16, a number of slots in a resource pool for a period of PSFCH transmission occasion resources. If the number is zero, PSFCH transmissions from the UE in the resource pool are disabled. A UE expects that a slot t′ k   SL  (0≤k&lt;T′ max ) has a PSFCH transmission occasion resource if k mod N PSFCH   PSSCH =0, where t′ k   SL  is a slot that belongs to the resource pool, T′ max  is a number of slots that belong to the resource pool within 10240 msec, and N PSFCH   PSSCH  is provided by sl-PSFCH-Period-r16. A UE may be indicated by higher layers to not transmit a PSFCH in response to a PSSCH reception. If a UE receives a PSSCH in a resource pool and the HARQ feedback enabled/disabled indicator field in an associated SCI format 2-A or a SCI format 2-B has value 1, the UE provides the HARQ-ACK information in a PSFCH transmission in the resource pool. The UE transmits the PSFCH in a first slot that includes PSFCH resources and is at least a number of slots, provided by sl-MinTimeGapPSFCH-r16, of the resource pool after a last slot of the PSSCH reception. 
     A UE is provided by sl-PSFCH-RB-Set-r16 a set of M PSFCH   PB,set  PRBs in a resource pool for PSFCH transmission in a PRB of the resource pool. For a number of N subch  sub-channels for the resource pool, provided by sl-NumSubchannel, and a number of PSSCH slots associated with a PSFCH slot that is less than or equal to N PSFCH   PSSCH , the UE allocates the [(i+j·N PSFCH   PSSCH )·M PSFCH   subch,slot , (i+1+j·N PSFCH   PSSCH )·M PSFCH   subch,slot −1] PRBs from the M PRB,set   PSFCH  PRBs to slot i among the PSSCH slots associated with the PSFCH slot and sub-channel j, where M PSFCH   subch,slot =M PSFCH   PRB,set /(N subch  N PSFCH   PSSCH ), 0≤i&lt;N PSFCH   PSSCH , 0≤j&lt;N subch , and the allocation starts in an ascending order of i and continues in an ascending order of j. The UE expects that M PSFCH   PRB,set  is a multiple of N subch ·N PSFCH   PSSCH . 
     A UE determines a number of PSFCH resources available for multiplexing HARQ-ACK information in a PSFCH transmission as R PSFCH   PRB,CS =N PSFCH   type ·M PSFCH   subch,slot ·N PSFCH   CS  where N PSFCH   CS  is a number of cyclic shift pairs for the resource pool and, based on an indication by higher layers, 
     N PSFCH   type =1 and the M PSFCH   subch,slot  PRBs are associated with the starting sub-channel of the corresponding PSSCH 
     N PSFCH   type =N PSSCH   subch  and the N PSSCH   subch ·M PSFCH   subch,slot  PRBs are associated with one or more sub-channels from the N PSSCH   subch  sub-channels of the corresponding PSSCH 
     The PSFCH resources are first indexed according to an ascending order of the PRB index, from the N PSFCH   type ·M PSFCH   subch,slot  PRBs, and then according to an ascending order of the cyclic shift pair index from the N PSFCH   CS  cyclic shift pairs. 
     A UE determines an index of a PSFCH resource for a PSFCH transmission in response to a PSSCH reception as (P ID +M ID ) mod R PSFCH   PRB,CS  where P ID  is a physical layer source ID provided by SCI format 2-A or 2-B scheduling the PSSCH reception, and M ID  is the identity of the UE receiving the PSSCH as indicated by higher layers if the UE detects a SCI format 2-A with Cast type indicator field value of “01”; otherwise, M ID  is zero. 
     A UE determines a m 0  value, for computing a value of cyclic shift α, from a cyclic shift pair index corresponding to a PSFCH resource index and from N PSFCH   CS  using Table 8. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 8 
               
             
            
               
                   
                   
               
               
                   
                   
                 m 0   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                   
                   
                 cyclic  
                 cyclic  
                 cyclic  
                 cyclic  
                 cyclic  
                 cyclic  
               
               
                   
                   
                 shift 
                 shift 
                 shift 
                 shift 
                 shift 
                 shift 
               
               
                   
                   
                 pair  
                 pair  
                 pair  
                 pair  
                 pair  
                 pair  
               
               
                   
                   
                 index 
                 index 
                 index 
                 index 
                 index 
                 index 
               
               
                   
                 N CS   PSFCH   
                 0 
                 1 
                 2 
                 3 
                 4 
                 5 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                   
                 1 
                 0 
                 — 
                 — 
                 — 
                 — 
                 — 
               
               
                   
                 2 
                 0 
                 3 
                 — 
                 — 
                 — 
                 — 
               
               
                   
                 3 
                 0 
                 2 
                 4 
                 — 
                 — 
                 — 
               
               
                   
                 6 
                 0 
                 1 
                 2 
                 3 
                 4 
                 5 
               
               
                   
                   
               
            
           
         
       
     
     A UE determines a m cs  value, for computing a value of cyclic shift α, as in Table 9 if the UE detects a SCI format 2-A with Cast type indicator field value of “01” or “10”, or as in Table 10 if the UE detects a SCI format 2-B or a SCI format 2-A with Cast type indicator field value of “11”. The UE applies one cyclic shift from a cyclic shift pair to a sequence used for the PSFCH transmission. 
     
       
         
           
               
               
               
               
             
               
                   
                 TABLE 9 
               
               
                   
                   
               
               
                   
                 HARQ-ACK Value 
                 0 (NACK) 
                 1 (ACK) 
               
               
                   
                   
               
             
            
               
                   
                 Sequence cyclic shift 
                 0 
                 6 
               
               
                   
                   
               
            
           
         
       
     
     
       
         
           
               
               
               
               
             
               
                   
                 TABLE 10 
               
               
                   
                   
               
               
                   
                 HARQ-ACK Value 
                 0 (NACK) 
                 1 (ACK) 
               
               
                   
                   
               
             
            
               
                   
                 Sequence cyclic shift 
                 0 
                 N/A 
               
               
                   
                   
               
            
           
         
       
     
     Meanwhile, in NR V2X of Release 16, a power saving operation of a UE was not supported. On the other hand, from NR V2X of Release 17, the power saving operation of a UE (e.g., Power Saving UE) will be supported. 
     Meanwhile, for the power saving operation of the UE (e.g., SL DRX operation), a SL DRX configuration (e.g., SL DRX cycle(s), SL DRX on-duration timer(s), SL DRX slot offset(s) (e.g., offset(s) representing/indicating the start time of the SL DRX on-duration timer(s)), SL DRX start offset(s) (e.g., offset(s) representing/indicating the start time of the SL DRX cycle(s)), timer(s) to support SL DRX operation, etc.) to be used by a power saving UE (P-UE) should be defined. In addition, in on-duration (e.g., duration in which sidelink reception/transmission can be performed) and/or off-duration (e.g., duration operating in a sleep mode), the behavior of a transmitting (TX) UE and a receiving (RX) UE should be defined. 
       FIG. 8  is a drawing for explaining a problem according to the prior art. 
     Referring to  FIG. 8 , if an RX UE supporting a SL DRX operation receives a SCI (e.g., the SCI including reservation transmission scheduling information for PSSCH (i.e., SL data) reception) transmitted by a TX UE, the RX UE may maintain an active state until the RX UE receives all PSCCHs/PSSCHs (e.g., up to three PSSCHs) transmitted by the TX UE using the reserved transmission resource(s). Thereby, the RX UE may monitor (or receive) the PSCCHs/PSSCHs transmitted by the TX UE. That is, the RX UE may be in an active state in a first time interval between a first resource and a second resource on which transmission is not performed by the TX UE, and the RX UE may be in an active state in a second time interval between the second resource and a third resource in which transmission is not performed by the TX UE. In other words, even if the RX UE which has decoded the SCI transmitted by the TX UE knows/determines that transmission is not performed by the TX UE (i) in the first time interval between the first resource and the second resource and/or (ii) in the second time interval between the second resource and the third resource, the RX UE may be in an active state in the first time interval and/or in the second time interval, unnecessarily. This may cause unnecessary power consumption of the RX UE. 
       FIG. 9  is a drawing for explaining a problem according to the prior art. 
     Referring to  FIG. 9 , if the RX UE supporting the SL DRX operation receives a SCI (e.g., the SCI including reservation transmission schedule information for PSSCH (i.e., SL data) reception) transmitted by the TX UE, the RX UE may determine the location of the reserved transmission resource(s), and the RX UE may monitor SL data transmitted by the TX UE at the location of the reserved transmission resource(s). In the case of the RX UE which performs the SL DRX operation, even if the location of the next transmission resource reserved through the SCI is in a SL DRX inactive time (e.g., a period that does not need to monitor a PSCCH/PSSCH, a period that can operate in a SL sleep mode), the RX UE may wake up from the transmission period reserved through the SCI and monitor and receive SL data transmitted by the TX UE. However, according to the conventional NR V2X release 16 technology, only if the interval between the previous transmission and the next transmission (e.g., retransmission) of the TX UE is within 32 slots, the TX UE can reserve chained transmission resources through a plurality of SCIs. As in the embodiment of  FIG. 9 , if the base station allocates mode 1 resources to the TX UE, the base station may allocate the next transmission resource (e.g., retransmission resource) in a location out of 32 slots from the previous transmission resource. In other words, the slot interval between the previous transmission resource and the next transmission resource (e.g., retransmission resource) may be greater than 32 slots. In this case, the TX UE cannot include resource reservation information for the fourth transmission in a SCI related to the third transmission. That is, if the RX UE receives the SCI related to the third transmission resource, the RX UE may determine/consider transmission on the third resource as the last transmission, and the RX UE may transition to a sleep mode during the remaining SL inactive time period. In this case, the RX UE may not receive the fourth transmission transmitted by the TX UE. 
     Based on various embodiments of the present disclosure, a method for performing a SL power saving operation, by an RX UE which receives a SCI (including reserved transmission resource information) and a PSSCH (e.g., SL data) related to the SCI transmitted by a TX UE, based on the reservation transmission resource information included in the SCI, and an apparatus supporting the same, are proposed. In addition, a SL DRX operation according to whether or not a SL DRX HARQ round trip time (RTT) timer and/or a SL DRX retransmission timer is supported is proposed. 
     Based on various embodiments of the present disclosure, a method for performing a SL power saving operation, by an RX UE which receives a SCI (including reserved transmission resource information) and a PSSCH (e.g., SL data) related to the SCI transmitted by a TX UE, based on the reservation transmission resource information included in the SCI, and an apparatus supporting the same, are proposed. 
     The SL DRX configuration referred to in the present disclosure may include at least one of parameters/information among the following parameters/information. 
     (1) SL drx-onDurationTimer: the duration at the beginning of a SL DRX Cycle 
     (2) SL drx-SlotOffset: the delay before starting the sl drx-onDurationTimer 
     (3) SL drx-InactivityTimer: the duration after the PSCCH occasion in which a PSCCH indicates a new SL transmission for the MAC entity 
     (4) SL drx-StartOffset: the subframe where the SL DRX cycle starts (the subframe where the SL DRX cycle start) 
     (5) SL drx-Cycle: SL DRX cycle 
     (6) SL drx-HARQ-RTT-Timer (per HARQ process or per sidelink process): the minimum duration before an assignment for HARQ retransmission is expected by the MAC entity 
     (7) SL drx-RetransmissionTimer (per HARQ process or per sidelink process): the maximum duration until a retransmission is received 
     The following SL DRX timer referred to in the present disclosure may be used for the following purposes. 
     (1) SL DRX on-duration timer: the duration in which a UE performing the SL DRX operation should basically operate in an active time for PSCCH/PSSCH reception of a counterpart UE 
     (2) SL DRX inactivity timer: the duration in which a UE performing the SL DRX operation extends the SL DRX on-duration period, which is the duration in which the UE should basically operate in an active time for PSCCH/PSSCH reception of a counterpart UE 
     For example, the UE may extend the SL DRX on-duration timer by the SL DRX inactivity timer duration. Also, if the UE receives a new packet (e.g., new PSSCH transmission) from the counterpart UE, the UE may extend the SL DRX on-duration timer by starting the SL DRX inactivity timer. 
     For example, the SL DRX inactivity timer may be used to extend the duration of the SL DRX on-duration timer, which is the duration in which the RX UE performing the SL DRX operation should basically operate in an active time for PSCCH/PSSCH reception of a counterpart TX UE. That is, the SL DRX on-duration timer may be extended by the duration of the SL DRX inactivity timer. In addition, if the RX UE receives a new packet (e.g., new PSSCH transmission) from the counterpart TX UE, the RX UE may extend the SL DRX on-duration timer by starting the SL DRX inactivity timer. 
     (3) SL DRX HARQ RTT Timer: the duration in which a UE performing the SL DRX operation operates in a sleep mode until the UE receives a retransmission packet (or PSSCH assignment) transmitted by a counterpart UE 
     For example, if the UE starts the SL DRX HARQ RTT timer, the UE may determine that the counterpart UE will not transmit a sidelink retransmission packet to the UE until the SL DRX HARQ RTT timer expires, and the UE may operate in a sleep mode while the corresponding timer is running. For example, if the UE starts the SL DRX HARQ RTT timer, the UE may not monitor the sidelink retransmission packet from the counterpart UE until the SL DRX HARQ RTT timer expires. For example, if the RX UE which has received a PSCCH/PSSCH transmitted by the TX UE transmits SL HARQ NACK feedback, the RX UE may start the SL DRX HARQ RTT timer. In this case, the RX UE may determine that the counterpart TX UE will not transmit a sidelink retransmission packet to the RX UE until the SL DRX HARQ RTT timer expires, and the RX UE may operate in a sleep mode while the corresponding timer is running. 
     (4) SL DRX retransmission timer: the timer which starts when the SL DRX HARQ RTT timer expires, and the duration in which a UE performing the SL DRX operation operates in an active time to receive a retransmission packet (or PSSCH assignment) transmitted by a counterpart UE 
     For example, during the corresponding timer duration, the UE may receive or monitor the retransmission sidelink packet (or PSSCH assignment) transmitted by the counterpart UE. For example, the RX UE may receive or monitor a retransmission sidelink packet (or PSSCH assignment) transmitted by the counterpart TX UE while the SL DRX retransmission timer is running. 
     In the present disclosure, the names of timers (Uu DRX HARQ RTT TimerSL, Uu DRX Retransmission TimerSL, Sidelink DRX Onduration Timer, Sidelink DRX Inactivity Timer, Sidelink DRX HARQ RTT Timer, Sidelink DRX Retransmission Timer, etc.) are exemplary, and a timer performing the same/similar function based on the description of each timer may be regarded as the same/similar timer regardless of its name. 
     Based on an embodiment of the present disclosure, the RX UE which receives a SCI transmitted by the TX UE may perform a hybrid SL DRX operation in which a SL DRX operation in which the SL DRX HARQ RTT timer and/or the SL DRX retransmission timer is not operated and a SL DRX operation in which the SL DRX HARQ RTT timer and/or the SL DRX retransmission timer is operated are mixed, based on transmission resource reservation information included in the SCI. 
     For example, after the RX UE receives/decodes a SCI transmitted by the TX UE and a PSSCH (e.g., SL data) related to the SCI, if NACK is generated, the RX UE may transmit SL HARQ NACK feedback to the TX UE. According to the prior art, after the RX UE supporting the SL DRX operation transmits HARQ NACK to the TX UE, the RX UE may start the SL DRX HARQ RTT timer, and the RX UE may operate in a sleep mode until the SL DRX HARQ RTT timer expires, and the RX UE may transition to a SL active mode and start the SL DRX retransmission timer if the SL DRX HARQ RTT timer expires, and the RX UE may receive a SL retransmission packet which is retransmitted by the TX UE until the SL DRX retransmission timer expires. 
     However, based on an embodiment of the present disclosure, if the RX UE receives and decodes a SCI and a PSSCH (e.g., SL data) related to the SCI transmitted by the TX UE, and if HARQ NACK is generated, the RX UE may not start the SL DRX HARQ RTT timer after transmitting a PSFCH (e.g., SL HARQ NACK feedback) to the TX UE and may operate in a sleep mode until the location of the next transmission resource reserved by the SCI related to the PSSCH (e.g., SL data) in which NACK is generated. For example, if the RX UE receives and decodes a SCI and a PSSCH (e.g., SL data) related to the SCI transmitted by the TX UE, and if a HARQ feedback mode (i.e., HARQ feedback enabled/disabled indicator) indicated by the SCI is set to HARQ Feedback Enabled, and if HARQ NACK is generated, the RX UE may not start the SL DRX HARQ RTT timer after transmitting a PSFCH (e.g., SL HARQ NACK feedback) to the TX UE and may operate in a sleep mode until the location of the next transmission resource reserved by the SCI related to the PSSCH (e.g., SL data) in which NACK is generated. For example, even if the HARQ feedback mode (i.e., HARQ feedback enabled/disabled indicator) indicated by the SCI is set to HARQ Feedback Disabled, the RX UE may operate as the above proposal. For example, if the RX UE receives and decodes a SCI and a PSSCH (e.g., SL data) related to the SCI transmitted by the TX UE, and if a HARQ feedback mode (i.e., HARQ feedback enabled/disabled indicator) indicated by the SCI is set to HARQ Feedback Disabled, and if HARQ NACK is generated, the RX UE may not start the SL DRX HARQ RTT timer and may operate in a sleep mode until the location of the next transmission resource reserved by the SCI related to the PSSCH (e.g., SL data) in which NACK is generated. In addition, the RX UE may receive a SL retransmission packet retransmitted by the TX UE by transitioning from the sleep mode to the active mode at the location of the next transmission resource. 
       FIG. 10  shows a method for a UE to transmit/receive data based on resource reservation information included in a SCI, based on an embodiment of the present disclosure. The embodiment of  FIG. 10  may be combined with various embodiments of the present disclosure. 
     Referring to  FIG. 10 , if the RX UE receives and decodes the first transmission (e.g., a first SCI, a second SCI and a MAC PDU) by the TX UE, and if the RX UE fails to decode for the first transmission, the RX UE may not start the SL DRX HARQ RTT timer and may operate in a sleep mode until the location of the next transmission resource (i.e., the second transmission resource) reserved by the SCI related to the PSSCH (e.g., SL data) in which NACK is generated. In addition, the RX UE may transition from the sleep mode to an active mode at the location of the next transmission resource (i.e., the second transmission resource), and receive a SL retransmission packet retransmitted by the TX UE. For example, if the RX UE receives and decodes the second transmission (e.g., a first SCI, a second SCI and a MAC PDU) by the TX UE, and if the RX UE fails to decode for the second transmission, the RX UE may not start the SL DRX HARQ RTT timer and may operate in a sleep mode until the location of the next transmission resource (i.e., the third transmission resource) reserved by the SCI related to the PSSCH (e.g., SL data) in which NACK is generated. In addition, the RX UE may transition from the sleep mode to an active mode at the location of the next transmission resource (i.e., the third transmission resource), and receive a SL retransmission packet retransmitted by the TX UE. 
     For example, if the RX UE receives and decodes the first transmission (e.g., a first SCI, a second SCI and a MAC PDU) by the TX UE, and if a HARQ feedback mode (i.e., HARQ feedback enabled/disabled indicator) indicated by the second SCI is set to HARQ Feedback Enabled, and if the RX UE fails to decode for the first transmission, the RX UE may not start the SL DRX HARQ RTT timer after transmitting a PSFCH (e.g., SL HARQ NACK feedback) to the TX UE and may operate in a sleep mode until the location of the next transmission resource (i.e., the second transmission resource) reserved by the SCI related to the PSSCH (e.g., SL data) in which NACK is generated. In addition, the RX UE may transition from the sleep mode to an active mode at the location of the next transmission resource (i.e., the second transmission resource), and receive a SL retransmission packet retransmitted by the TX UE. For example, if the RX UE receives and decodes the second transmission (e.g., a first SCI, a second SCI and a MAC PDU) by the TX UE, and if a HARQ feedback mode (i.e., HARQ feedback enabled/disabled indicator) indicated by the second SCI is set to HARQ Feedback Enabled, and if the RX UE fails to decode for the second transmission, the RX UE may not start the SL DRX HARQ RTT timer after transmitting a PSFCH (e.g., SL HARQ NACK feedback) to the TX UE and may operate in a sleep mode until the location of the next transmission resource (i.e., the third transmission resource) reserved by the SCI related to the PSSCH (e.g., SL data) in which NACK is generated. In addition, the RX UE may transition from the sleep mode to an active mode at the location of the next transmission resource (i.e., the third transmission resource), and receive a SL retransmission packet retransmitted by the TX UE. 
     For example, if the RX UE receives and decodes the first transmission (e.g., a first SCI, a second SCI and a MAC PDU) by the TX UE, and if a HARQ feedback mode (i.e., HARQ feedback enabled/disabled indicator) indicated by the second SCI is set to HARQ Feedback Disabled, and if the RX UE fails to decode for the first transmission, the RX UE may not start the SL DRX HARQ RTT timer and may operate in a sleep mode until the location of the next transmission resource (i.e., the second transmission resource) reserved by the SCI related to the PSSCH (e.g., SL data) in which NACK is generated. In addition, the RX UE may transition from the sleep mode to an active mode at the location of the next transmission resource (i.e., the second transmission resource), and receive a SL retransmission packet retransmitted by the TX UE. For example, if the RX UE receives and decodes the second transmission (e.g., a first SCI, a second SCI and a MAC PDU) by the TX UE, and if a HARQ feedback mode (i.e., HARQ feedback enabled/disabled indicator) indicated by the second SCI is set to HARQ Feedback Disabled, and if the RX UE fails to decode for the second transmission, the RX UE may not start the SL DRX HARQ RTT timer and may operate in a sleep mode until the location of the next transmission resource (i.e., the third transmission resource) reserved by the SCI related to the PSSCH (e.g., SL data) in which NACK is generated. In addition, the RX UE may transition from the sleep mode to an active mode at the location of the next transmission resource (i.e., the third transmission resource), and receive a SL retransmission packet retransmitted by the TX UE. 
     In addition, as in the embodiment of  FIG. 10 , in the case of mode 1 resources which are allocated to the TX UE, the base station may allocate the next transmission resource in a location out of 32 slots from the previous transmission resource. In this case, the TX UE cannot indicate the reservation resource between the previous transmission and the next transmission through a SCI as a chain format. That is, the TX UE cannot indicate/reserve the next transmission resource through the previously transmitted SCI. In this case, the TX UE may include only resource information related to the current PSSCH transmission in the SCI (e.g., the SCI related to the third transmission in the embodiment of  FIG. 10 ). That is, the TX UE cannot indicate resource information for the next fourth transmission through the SCI. Therefore, based on an embodiment of the present disclosure, if the RX UE receives a SCI including only resource information for the current PSSCH transmission (i.e., the SCI that does not include transmission resource information for the next transmission (e.g., a retransmission packet)), the RX UE may start the SL DRX HARQ RTT timer, and the RX UE may transition to a sleep mode until the SL DRX HARQ RTT timer expires. In addition, if the SL DRX HARQ RTT timer expires, the RX UE may transition from the sleep mode to an active mode and start the SL DRX retransmission timer, and the RX UE may receive the next PSCCH/PSSCH transmitted by the TX UE (e.g., the fourth transmission and the associated SCI in the embodiment of  FIG. 10 ). 
       FIG. 11  shows a procedure for an RX UE to perform an SL DRX operation based on resource reservation information included in a SCI, based on an embodiment of the present disclosure. The embodiment of  FIG. 11  may be combined with various embodiments of the present disclosure. 
     Referring to  FIG. 11 , in step S 1110 , the RX UE may obtain a SL DRX configuration. For example, the RX UE may receive the SL DRX configuration from the TX UE. Alternatively, for example, the SL DRX configuration may be configured or pre-configured for the RX UE and the TX UE. For example, the SL DRX configuration may include information related to active timer(s) (e.g., an on-duration timer, a retransmission timer, an inactivity timer, etc.). For example, the SL DRX configuration may include information related to a SL DRX HARQ RTT timer. 
     In step S 1120 , the RX UE may start the active timer. For example, while the active timer is running, the RX UE may be in an active state. 
     In step S 1130 , the RX UE may receive, from the TX UE through a PSCCH, a first SCI for scheduling a PSSCH and a second SCI based on a first SL resource. For example, the first SCI may include information related to at least one SL resource. For example, the first SCI may include information related to the first SL resource. For example, the first SCI may include information related to the first SL resource and a second SL resource. For example, the first SCI may include information related to the first SL resource, a second SL resource, and a third SL resource. For example, the first SL resource may be a resource through which the first SCI is transmitted, and the second SL resource may be a resource located after the first SL resource in a time domain, and the third SL resource may be a resource located after the second SL resource in the time domain. 
     In step S 1140 , the RX UE may receive, from the TX UE through the PSSCH, the second SCI and data (e.g., MAC PDU) based on the first SL resource. 
     In this case, the RX UE may perform the SL DRX operation based on the resource allocation information included in the first SCI. Specifically, for example, if information related to the first SL resource and the second SL resource is included in the first SCI, the RX UE may determine that the TX UE does not perform retransmission for the MAC PDU between the first SL resource and the second SL resource, and the RX UE may not monitor a PSCCH related to the MAC PDU between the first SL resource and the second SL resource. On the other hand, for example, if only information related to the first SL resource is included in the first SCI (i.e., information related to the second SL resource is not included in the first SCI), in step S 1150 , the RX UE may start the SL DRX HARQ RTT timer. For example, the SL DRX HARQ RTT timer may be a zero or positive integer. In addition, in step S 1160 , the RX UE may start the SL DRX retransmission timer if the SL DRX HARQ RTT timer expires. 
     The proposal of the present disclosure can be extended and applied to a case in which the SL DRX inactivity timer is operated as follows. 
     Based on an embodiment of the present disclosure, the RX UE which receives a SCI transmitted by the TX UE may perform a hybrid SL DRX operation in which a SL DRX operation in which the SL DRX inactivity timer is not operated and a SL DRX operation in which the SL DRX inactivity timer is operated are mixed, based on transmission resource reservation information included in the SCI. 
     For example, after the RX UE receives/decodes a SCI transmitted by the TX UE and a PSSCH (e.g., SL data) related to the SCI, if NACK is generated, the RX UE may transmit SL HARQ NACK feedback to the TX UE. According to the prior art, after the RX UE supporting the SL DRX operation transmits HARQ NACK to the TX UE, the RX UE may start the SL DRX HARQ RTT timer, and the RX UE may operate in a sleep mode until the SL DRX HARQ RTT timer expires, and the RX UE may transition to a SL active mode and start the SL DRX retransmission timer if the SL DRX HARQ RTT timer expires, and the RX UE may receive a SL retransmission packet which is retransmitted by the TX UE until the SL DRX retransmission timer expires. 
     However, based on an embodiment of the present disclosure, if the RX UE receives and decodes a SCI and a PSSCH (e.g., SL data) related to the SCI transmitted by the TX UE, and if HARQ NACK is generated, the RX UE may not start the SL DRX HARQ RTT timer after transmitting a PSFCH (e.g., SL HARQ NACK feedback) to the TX UE and may operate in a sleep mode until the location of the next transmission resource reserved by the SCI related to the PSSCH (e.g., SL data) in which NACK is generated. For example, if the RX UE receives and decodes a SCI and a PSSCH (e.g., SL data) related to the SCI transmitted by the TX UE, and if a HARQ feedback mode (i.e., HARQ feedback enabled/disabled indicator) indicated by the SCI is set to HARQ Feedback Enabled, and if HARQ NACK is generated, the RX UE may not start the SL DRX HARQ RTT timer after transmitting a PSFCH (e.g., SL HARQ NACK feedback) to the TX UE and may operate in a sleep mode until the location of the next transmission resource reserved by the SCI related to the PSSCH (e.g., SL data) in which NACK is generated. For example, even if the HARQ feedback mode (i.e., HARQ feedback enabled/disabled indicator) indicated by the SCI is set to HARQ Feedback Disabled, the RX UE may operate as the above proposal. For example, if the RX UE receives and decodes a SCI and a PSSCH (e.g., SL data) related to the SCI transmitted by the TX UE, and if a HARQ feedback mode (i.e., HARQ feedback enabled/disabled indicator) indicated by the SCI is set to HARQ Feedback Disabled, and if HARQ NACK is generated, the RX UE may not start the SL DRX HARQ RTT timer and may operate in a sleep mode until the location of the next transmission resource reserved by the SCI related to the PSSCH (e.g., SL data) in which NACK is generated. In addition, the RX UE may receive a SL retransmission packet retransmitted by the TX UE by transitioning from the sleep mode to the active mode at the location of the next transmission resource. 
       FIG. 12  shows a method for a UE to transmit/receive data based on resource reservation information included in a SCI, based on an embodiment of the present disclosure. The embodiment of  FIG. 12  may be combined with various embodiments of the present disclosure. 
     Referring to  FIG. 12 , if the RX UE receives and decodes the first transmission (e.g., a first SCI, a second SCI and a MAC PDU) by the TX UE, and if the RX UE fails to decode for the first transmission, the RX UE may not start the SL DRX HARQ RTT timer and may operate in a sleep mode until the location of the next transmission resource (i.e., the second transmission resource) reserved by the SCI related to the PSSCH (e.g., SL data) in which NACK is generated. In addition, the RX UE may transition from the sleep mode to an active mode at the location of the next transmission resource (i.e., the second transmission resource), and receive a SL retransmission packet retransmitted by the TX UE. For example, if the RX UE receives and decodes the second transmission (e.g., a first SCI, a second SCI and a MAC PDU) by the TX UE, and if the RX UE fails to decode for the second transmission, the RX UE may not start the SL DRX HARQ RTT timer and may operate in a sleep mode until the location of the next transmission resource (i.e., the third transmission resource) reserved by the SCI related to the PSSCH (e.g., SL data) in which NACK is generated. In addition, the RX UE may transition from the sleep mode to an active mode at the location of the next transmission resource (i.e., the third transmission resource), and receive a SL retransmission packet retransmitted by the TX UE. 
     For example, if the RX UE receives and decodes the first transmission (e.g., a first SCI, a second SCI and a MAC PDU) by the TX UE, and if a HARQ feedback mode (i.e., HARQ feedback enabled/disabled indicator) indicated by the second SCI is set to HARQ Feedback Enabled, and if the RX UE fails to decode for the first transmission, the RX UE may not start the SL DRX HARQ RTT timer after transmitting a PSFCH (e.g., SL HARQ NACK feedback) to the TX UE and may operate in a sleep mode until the location of the next transmission resource (i.e., the second transmission resource) reserved by the SCI related to the PSSCH (e.g., SL data) in which NACK is generated. In addition, the RX UE may transition from the sleep mode to an active mode at the location of the next transmission resource (i.e., the second transmission resource), and receive a SL retransmission packet retransmitted by the TX UE. For example, if the RX UE receives and decodes the second transmission (e.g., a first SCI, a second SCI and a MAC PDU) by the TX UE, and if a HARQ feedback mode (i.e., HARQ feedback enabled/disabled indicator) indicated by the second SCI is set to HARQ Feedback Enabled, and if the RX UE fails to decode for the second transmission, the RX UE may not start the SL DRX HARQ RTT timer after transmitting a PSFCH (e.g., SL HARQ NACK feedback) to the TX UE and may operate in a sleep mode until the location of the next transmission resource (i.e., the third transmission resource) reserved by the SCI related to the PSSCH (e.g., SL data) in which NACK is generated. In addition, the RX UE may transition from the sleep mode to an active mode at the location of the next transmission resource (i.e., the third transmission resource), and receive a SL retransmission packet retransmitted by the TX UE. 
     For example, if the RX UE receives and decodes the first transmission (e.g., a first SCI, a second SCI and a MAC PDU) by the TX UE, and if a HARQ feedback mode (i.e., HARQ feedback enabled/disabled indicator) indicated by the second SCI is set to HARQ Feedback Disabled, and if the RX UE fails to decode for the first transmission, the RX UE may not start the SL DRX HARQ RTT timer and may operate in a sleep mode until the location of the next transmission resource (i.e., the second transmission resource) reserved by the SCI related to the PSSCH (e.g., SL data) in which NACK is generated. In addition, the RX UE may transition from the sleep mode to an active mode at the location of the next transmission resource (i.e., the second transmission resource), and receive a SL retransmission packet retransmitted by the TX UE. For example, if the RX UE receives and decodes the second transmission (e.g., a first SCI, a second SCI and a MAC PDU) by the TX UE, and if a HARQ feedback mode (i.e., HARQ feedback enabled/disabled indicator) indicated by the second SCI is set to HARQ Feedback Disabled, and if the RX UE fails to decode for the second transmission, the RX UE may not start the SL DRX HARQ RTT timer and may operate in a sleep mode until the location of the next transmission resource (i.e., the third transmission resource) reserved by the SCI related to the PSSCH (e.g., SL data) in which NACK is generated. In addition, the RX UE may transition from the sleep mode to an active mode at the location of the next transmission resource (i.e., the third transmission resource), and receive a SL retransmission packet retransmitted by the TX UE. 
     In addition, as in the embodiment of  FIG. 12 , in the case of mode 1 resources which are allocated to the TX UE, the base station may allocate the next transmission resource in a location out of 32 slots from the previous transmission resource. In this case, the TX UE cannot indicate the reservation resource between the previous transmission and the next transmission through a SCI as a chain format. That is, the TX UE cannot indicate/reserve the next transmission resource through the previously transmitted SCI. In this case, the TX UE may include only resource information related to the current PSSCH transmission in the SCI (e.g., the SCI related to the third transmission in the embodiment of  FIG. 12 ). That is, the TX UE cannot indicate resource information for the next fourth transmission through the SCI. Therefore, based on an embodiment of the present disclosure, if the RX UE receives a SCI including only resource information for the current PSSCH transmission (i.e., the SCI that does not include transmission resource information for the next transmission (e.g., a retransmission packet)), the RX UE may start the SL DRX inactivity timer, and the RX UE may receive the next PSCCH/PSSCH transmitted by the TX UE (e.g., the fourth transmission and the associated SCI in the embodiment of  FIG. 12 ) until the SL DRX inactivity timer expires. 
       FIG. 13  shows a procedure for an RX UE to perform an SL DRX operation based on resource reservation information included in a SCI, based on an embodiment of the present disclosure. The embodiment of  FIG. 13  may be combined with various embodiments of the present disclosure. 
     Referring to  FIG. 13 , in step S 1310 , the RX UE may obtain a SL DRX configuration. For example, the RX UE may receive the SL DRX configuration from the TX UE. Alternatively, for example, the SL DRX configuration may be configured or pre-configured for the RX UE and the TX UE. For example, the SL DRX configuration may include information related to active timer(s) (e.g., an on-duration timer, a retransmission timer, an inactivity timer, etc.). For example, the SL DRX configuration may include information related to a SL DRX HARQ RTT timer. 
     In step S 1320 , the RX UE may start the active timer. For example, while the active timer is running, the RX UE may be in an active state. 
     In step S 1330 , the RX UE may receive, from the TX UE through a PSCCH, a first SCI for scheduling a PSSCH and a second SCI based on a first SL resource. For example, the first SCI may include information related to at least one SL resource. For example, the first SCI may include information related to the first SL resource. For example, the first SCI may include information related to the first SL resource and a second SL resource. For example, the first SCI may include information related to the first SL resource, a second SL resource, and a third SL resource. For example, the first SL resource may be a resource through which the first SCI is transmitted, and the second SL resource may be a resource located after the first SL resource in a time domain, and the third SL resource may be a resource located after the second SL resource in the time domain. 
     In step S 1340 , the RX UE may receive, from the TX UE through the PSSCH, the second SCI and data (e.g., MAC PDU) based on the first SL resource. 
     In this case, the RX UE may perform the SL DRX operation based on the resource allocation information included in the first SCI. Specifically, for example, if information related to the first SL resource and the second SL resource is included in the first SCI, the RX UE may determine that the TX UE does not perform retransmission for the MAC PDU between the first SL resource and the second SL resource, and the RX UE may not monitor a PSCCH related to the MAC PDU between the first SL resource and the second SL resource. On the other hand, for example, if only information related to the first SL resource is included in the first SCI (i.e., information related to the second SL resource is not included in the first SCI), in step S 1350 , the RX UE may start the SL DRX inactivity timer. 
     In the present disclosure, technical issues of SL DRX for SL DRX wake-up time alignment between inter-UEs are further discussed. 
     Since the SL DRX operation is from a reception point of view, it may be desirable for the Rx UE to determine the SL DRX configuration (e.g., SL DRX wake-up time). However, since the TX UE can also perform the RX UE operation by changing its role, the RX UE should not arbitrarily decide the SL DRX configuration (e.g., SL DRX wake-up time), but rather refer to the SL DRX wake-up time assistance information (e.g., traffic characteristic of sidelink logical channel(s), sidelink traffic pattern information, and preferred SL DRX wake-up time) of the counterpart UE (e.g., TX UE) that has a PC5 RRC connection. In addition, if the RX UE operating the SL DRX also becomes a TX UE and there is SL data to be transmitted to the other UE, it can provide the SL DRX wake-up time assistance information (e.g., traffic characteristic of sidelink logical channel(s), sidelink traffic pattern information, and preferred SL DRX wake-up time) for its SL TX to the counterpart UE. 
     Besides, the UE performing the Rx operation can check whether the received Target/Peer UE related SL DRX wake-up time assistance information is a reference configuration that satisfies a predetermined condition, and if so, the UE may decide to match its SL DRX wake-up time as much as possible with the SL DRX wake-up time received from the RX UE. However, it is UE implementation that makes SL DRX wake-up time consistent with reference configuration. 
     For example, a SL DRX configuration (e.g., SL DRX wake-up time) that satisfies the conditions below can be considered a reference configuration. 
     SL DRX Configuration Determined by gNB 
     For example, when the TX UE (or RX UE) delivers the SL DRX configuration determined by the gNB to the RX UE (or TX UE), the TX UE (or RX UE) may also deliver with an indication that the SL DRX configuration has been determined by the gNB. 
     SL DRX Configuration of UE Performing Mode 1 Operation 
     SL DRX configuration of UE performing groupcast based on relatively large number of members 
       FIG. 14  shows a procedure for aligning SL DRX configurations between a TX UE and an RX UE, based on an embodiment of the present disclosure. The embodiment of  FIG. 14  may be combined with various embodiments of the present disclosure. 
     Referring to  FIG. 14 , when a UE  1  determines the SL DRX configuration (e.g., SL DRX wake-up time) and delivers it to a UE  2 , the UE 2  confirms the use of the SL DRX configuration (e.g., SL DRX wake-up time) of the UE  1  and transmits SL Data in the SL DRX On-duration of UE  1 . 
     Besides, the UE 2  can refer to the SL DRX configuration (e.g., SL DRX wake-up time) delivered by the UE  1  so that it can overlap as much as possible with the SL DRX configuration (e.g., SL DRX wake-up time) for its RX behaviour. In this case, the on-durations of UE  1  and UE  2  are overlapped, which has the advantage of reducing the power consumption of the UE  1  and the UE  2 . 
       FIG. 15  shows an example of alignment of SL DRX configurations between SL DRX of a UE  1  and SL DRX of a UE  2 , based on an embodiment of the present disclosure. The embodiment of  FIG. 15  may be combined with various embodiments of the present disclosure. 
     Since the SL DRX operation is from a reception point of view, it may be desirable for the RX UE to determine the SL DRX configuration (e.g., SL DRX wake-up time). 
     The final decision of the SL DRX configuration is performed by the UE performing the RX operation, except when the gNB directly determines the SL DRX configuration to the RRC Connected UE, and the final determined SL DRX configuration should be transmitted to the target UE/Peer UE. 
     The UE performing the RX operation should receive SL DRX wake-up time assistance information (e.g., traffic characteristic of sidelink logical channel(s), sidelink traffic pattern information, and preferred SL DRX wake-up time) from the target UE before determining its SL DRX configuration. 
     The SL DRX wake-up time assistance information (e.g., traffic characteristic of sidelink logical channel(s), sidelink traffic pattern information, and preferred SL DRX wake-up time) proposed in the present disclosure may be exchanged between UEs including the information in Table 11, and the UE may report it to the base station. 
     
       
         
           
               
               
               
             
               
                 TABLE 11 
               
               
                   
               
             
            
               
                   
                 SL-TrafficPatternInfo-r16::=      SEQUENCE 1 
                   
               
               
                   
                  trafficPeriodicity-r16           ENUMERATED {ms20, ms50, ms100, ms200,  
                   
               
               
                   
                 ms300, ms400, ms500, ms600, ms700, ms800, ms900, ms1000} 
                   
               
               
                   
                  timingOffset-r16              INTEGER (0..10239). 
                   
               
               
                   
                  messageSize-r16               BIT STRING (SIZE (8)), 
                   
               
               
                   
                  s1-QoS-FlowIdentity-r16          SL-QoS-FlowIdentity-r16 
                   
               
               
                   
                 } 
                   
               
               
                   
                  SL-PQI-r16 ::=     CHOICE { 
                   
               
               
                   
                  s1-StandardizedPQI-r16    INTEGER (0..255), 
                   
               
               
                   
                  s1-Non-StandardizecIPQI-r16 SEQUENCE { 
                   
               
               
                   
                   s1-ResourceType-r16     ENUMERATED {gbr, non-GBR, delayCriticalGBR, 
                   
               
               
                   
                 spare1} OPTIONAL,  -- Need R 
                   
               
               
                   
                   s1-PriontyLevel-r16      INTEGER (1..8)  OPTIONAL, -- Need R 
                   
               
               
                   
                   s1-PacketDelayBudget-r16  INTEGER (0..1023) OPTIONAL, -- Need R 
                   
               
               
                   
                   s1-PacketErrorRate-r16    INTEGER (0..9   OPTIONAL, -- Need R 
                   
               
               
                   
                   s1-AveragingWindow-r16   INTEGER (0..4095) OPTIONAL, -- Need R 
                   
               
               
                   
                   s1-MaxDataBurstVolume-r16 INTEGER (0..4095  OPTIONAL, -- Need R 
                   
               
               
                   
                  ... 
                   
               
               
                   
                  } 
                   
               
               
                   
                 } 
               
               
                   
               
            
           
         
       
     
     The proposals of the present disclosure may be limitedly applied to the SL HARQ Feedback Enabled mode. The proposals of the present disclosure may be limitedly applied to the SL HARQ Feedback Disabled mode. The proposals of the present disclosure may be equally applied to both the SL HARQ Feedback Enabled mode and the SL HARQ Feedback Disabled mode. 
     In the present disclosure, it is proposed whether the RX UE which receives a SCI transmitted by the TX UE performs the SL DRX timer-based SL DRX operation (e.g., SL DRX HARQ RTT timer and SL DRX retransmission timer) or the non-SL DRX timer-based SL DRX operation, based on the resource reservation information included in the SCI. If the SCI includes transmission resource information for the next transmission, the RX UE may not start the SL DRX timer (e.g., SL DRX HARQ RTT timer and SL DRX retransmission timer), and through this, the overhead of managing the SL DRX timer in the MAC entity may be reduced. Also, if the SCI does not include transmission resource information for the next transmission, the RX UE may perform the SL DRX operation based on the SL DRX timer (e.g., SL DRX HARQ RTT timer and SL DRX retransmission timer), and through this, it can be ensured that the RX UE can receive a sidelink retransmission packet transmitted by the TX UE without missing. 
     Various embodiments of the present disclosure may be applied to the duration in which the UE receives a SCI from the counterpart UE at the end of a SL active time (e.g., the duration in which the UE monitors a SL channel or a signal) and the duration in which the next transmission resource reserved through the SCI received at the active time is in a SL inactive time (e.g., the duration in which the UE does not need to monitor a SL channel or a signal, or the duration in which the UE can operate in a power saving mode). In addition, various embodiments of the present disclosure may be equally applied to the duration of the SL active time and the duration of the SL inactive time of the UE. 
     Based on various embodiments of the present disclosure, the RX UE may perform different SL DRX operations based on resource reservation information included in the SCI. Therefore, while maximizing the power saving of the RX UE, it is possible to ensure that the RX UE receives the retransmission of the TX UE. Through this, the RX UE may obtain a power saving gain, and reliability of SL communication between the RX UE and the TX UE may be secured. 
     The proposal of the present disclosure can be applied/extended to/as a method of solving a problem in which loss occurs due to interruption which occurs during Uu BWP switching. In addition, in the case of a plurality of SL BWPs being supported for the UE, the proposal of the present disclosure can be applied/extended to/as a method of solving a problem in which loss occurs due to interruption which occurs during SL BWP switching. 
     The proposal of the present disclosure can be applied/extended to/as UE-pair specific SL DRX configuration(s), UE-pair specific SL DRX pattern(s) or parameter(s) (e.g., timer) included in UE-pair specific SL DRX configuration(s), as well as default/common SL DRX configuration(s), default/common SL DRX pattern(s), or parameter(s) (e.g., timer) included in default/common SL DRX configuration(s). In addition, the on-duration mentioned in the proposal of the present disclosure may be extended to or interpreted as an active time (e.g., time to wake-up state (e.g., RF module turned on) to receive/transmit radio signal(s)) duration, and the off-duration may be extended to or interpreted as a sleep time (e.g., time to sleep in sleep mode state (e.g., RF module turned off) to save power) duration. It does not mean that the TX UE is obligated to operate in the sleep mode in the sleep time duration. If necessary, the TX UE may be allowed to operate in an active time for a while for a sensing operation and/or a transmission operation, even if it is a sleep time. 
     For example, whether or not the (some) proposed method/rule of the present disclosure is applied and/or related parameter(s) (e.g., threshold value(s)) may be configured (differently or independently) for each resource pool. For example, whether or not the (some) proposed method/rule of the present disclosure is applied and/or related parameter(s) (e.g., threshold value(s)) may be configured (differently or independently) for each congestion level. For example, whether or not the (some) proposed method/rule of the present disclosure is applied and/or related parameter(s) (e.g., threshold value(s)) may be configured (differently or independently) for each service priority. For example, whether or not the (some) proposed method/rule of the present disclosure is applied and/or related parameter(s) (e.g., threshold value(s)) may be configured (differently or independently) for each service type. For example, whether or not the (some) proposed method/rule of the present disclosure is applied and/or related parameter(s) (e.g., threshold value(s)) may be configured (differently or independently) for each resource pool. For example, whether or not the (some) proposed method/rule of the present disclosure is applied and/or related parameter(s) (e.g., threshold value(s)) may be configured (differently or independently) for each QoS requirement (e.g., latency, reliability). For example, whether or not the (some) proposed method/rule of the present disclosure is applied and/or related parameter(s) (e.g., threshold value(s)) may be configured (differently or independently) for each PQI (5G QoS identifier (5QI) for PC5). For example, whether or not the (some) proposed method/rule of the present disclosure is applied and/or related parameter(s) (e.g., threshold value(s)) may be configured (differently or independently) for each traffic type (e.g., periodic generation or aperiodic generation). For example, whether or not the (some) proposed method/rule of the present disclosure is applied and/or related parameter(s) (e.g., threshold value(s)) may be configured (differently or independently) for each SL transmission resource allocation mode (e.g., mode 1 or mode 2). 
     For example, whether or not the proposed rule of the present disclosure is applied and/or related parameter configuration value(s) may be configured (differently or independently) for each resource pool. For example, whether or not the proposed rule of the present disclosure is applied and/or related parameter configuration value(s) may be configured (differently or independently) for each service/packet type. For example, whether or not the proposed rule of the present disclosure is applied and/or related parameter configuration value(s) may be configured (differently or independently) for each service/packet priority. For example, whether or not the proposed rule of the present disclosure is applied and/or related parameter configuration value(s) may be configured (differently or independently) for each QoS requirement (e.g., URLLC/EMBB traffic, reliability, latency). For example, whether or not the proposed rule of the present disclosure is applied and/or related parameter configuration value(s) may be configured (differently or independently) for each PQI. For example, whether or not the proposed rule of the present disclosure is applied and/or related parameter configuration value(s) may be configured (differently or independently) for each cast type (e.g., unicast, groupcast, broadcast). For example, whether or not the proposed rule of the present disclosure is applied and/or related parameter configuration value(s) may be configured (differently or independently) for each (resource pool) congestion level (e.g., CBR). For example, whether or not the proposed rule of the present disclosure is applied and/or related parameter configuration value(s) may be configured (differently or independently) for each SL HARQ feedback option (e.g., NACK-only feedback, ACK/NACK feedback). For example, whether or not the proposed rule of the present disclosure is applied and/or related parameter configuration value(s) may be configured specifically (or differently or independently) for HARQ Feedback Enabled MAC PDU transmission. For example, whether or not the proposed rule of the present disclosure is applied and/or related parameter configuration value(s) may be configured specifically (or differently or independently) for HARQ Feedback Disabled MAC PDU transmission. For example, whether or not the proposed rule of the present disclosure is applied and/or related parameter configuration value(s) may be configured specifically (or differently or independently) according to whether a PUCCH-based SL HARQ feedback reporting operation is configured or not. For example, whether or not the proposed rule of the present disclosure is applied and/or related parameter configuration value(s) may be configured specifically (or differently or independently) for pre-emption or pre-emption-based resource reselection. For example, whether or not the proposed rule of the present disclosure is applied and/or related parameter configuration value(s) may be configured specifically (or differently or independently) for re-evaluation or re-evaluation-based resource reselection. For example, whether or not the proposed rule of the present disclosure is applied and/or related parameter configuration value(s) may be configured (differently or independently) for each (L2 or L1) (source and/or destination) identifier. For example, whether or not the proposed rule of the present disclosure is applied and/or related parameter configuration value(s) may be configured (differently or independently) for each (L2 or L1) (a combination of source ID and destination ID) identifier. For example, whether or not the proposed rule of the present disclosure is applied and/or related parameter configuration value(s) may be configured (differently or independently) for each (L2 or L1) (a combination of a pair of source ID and destination ID and a cast type) identifier. For example, whether or not the proposed rule of the present disclosure is applied and/or related parameter configuration value(s) may be configured (differently or independently) for each direction of a pair of source layer ID and destination layer ID. For example, whether or not the proposed rule of the present disclosure is applied and/or related parameter configuration value(s) may be configured (differently or independently) for each PC5 RRC connection/link. For example, whether or not the proposed rule of the present disclosure is applied and/or related parameter configuration value(s) may be configured specifically (or differently or independently) for the case of performing SL DRX. For example, whether or not the proposed rule of the present disclosure is applied and/or related parameter configuration value(s) may be configured (differently or independently) for each SL mode type (e.g., resource allocation mode 1 or resource allocation mode 2). For example, whether or not the proposed rule of the present disclosure is applied and/or related parameter configuration value(s) may be configured specifically (or differently or independently) for the case of performing (a) periodic resource reservation. 
     The certain time mentioned in the proposal of the present disclosure may refer to a time during which a UE operates in an active time for a pre-defined time in order to receive sidelink signal(s) or sidelink data from a counterpart UE. The certain time mentioned in the proposal of the present disclosure may refer to a time during which a UE operates in an active time as long as a specific timer (e.g., sidelink DRX retransmission timer, sidelink DRX inactivity timer, or timer to ensure that an RX UE can operate in an active time in a DRX operation of the RX UE) is running in order to receive sidelink signal(s) or sidelink data from a counterpart UE. In addition, the proposal and whether or not the proposal rule of the present disclosure is applied (and/or related parameter configuration value(s)) may also be applied to a mmWave SL operation. 
       FIG. 16  shows a method for a first device to perform wireless communication, based on an embodiment of the present disclosure. The embodiment of  FIG. 16  may be combined with various embodiments of the present disclosure. 
     Referring to  FIG. 16 , in step S 1610 , the first device may obtain a sidelink (SL) discontinuous reception (DRX) configuration including information related to a timer for an active time and information related to a hybrid automatic repeat request (HARQ) round trip time (RTT) timer. In step S 1620 , the first device may start the timer for the active time. In step S 1630 , the first device may receive, from a second device through a physical sidelink control channel (PSCCH) based on a first SL resource, a first sidelink control information (SCI) for scheduling of a physical sidelink shared channel (PSSCH) and a second SC. In step S 1640 , the first device may receive, from the second device through the PSSCH based on the first SL resource, the second SCI and data. For example, based on resource allocation information for a second SL resource being included in the first SCI, the first device may not monitor retransmission of the data from the second device in a time domain between the first SL resource and the second SL resource, and based on the resource allocation information for the second SL resource not being included in the first SCI, the HARQ RTT timer included in the SL DRX configuration may be started by the first device. 
     For example, the second SCI may include information set to HARQ feedback enabled. Additionally, for example, the first device may generate NACK for the data based on failure of decoding for the data. Additionally, for example, the first device may determine a physical sidelink feedback channel (PSFCH) resource related to the PSSCH, based on at least one sub-channel index related to the PSSCH, a slot index related to the PSSCH, and a source ID of the second device included in the second SCI. Additionally, for example, the first device may transmit, to the second device, the NACK based on the PSFCH resource. For example, the time domain in which the retransmission of the data from the second device is not monitored may be a time domain after the PSFCH resource and before the second SL resource. 
     For example, the second SCI may include information set to HARQ feedback disabled. For example, the time domain in which the retransmission of the data from the second device is not monitored may be a time domain after the first SL resource and before the second SL resource. 
     For example, the time domain in which the retransmission of the data from the second device is not monitored may be determined based on a timing of the second SL resource. 
     For example, the HARQ RTT timer included in the SL DRX configuration may be started by the first device, based on only resource allocation information for the first SL resource being included in the first SCI. For example, after the HARQ RTT timer expires, a timer for active time may be started by the first device. 
     For example, the HARQ RTT timer included in the SL DRX configuration may not be started by the first device, based on the resource allocation information for the second SL resource being included in the first SCI. 
     For example, the timer for the active time may be a SL DRX on-duration timer, a SL DRX inactivity timer or a SL DRX retransmission timer. 
     For example, the second SL resource may be a SL resource for the retransmission of the data. 
     For example, the SL DRX configuration may be received from the second device. 
     The proposed method may be applied to the device(s) based on various embodiments of the present disclosure. First, the processor  102  of the first device  100  may obtain a sidelink (SL) discontinuous reception (DRX) configuration including information related to a timer for an active time and information related to a hybrid automatic repeat request (HARQ) round trip time (RTT) timer. In addition, the processor  102  of the first device  100  may start the timer for the active time. In addition, the processor  102  of the first device  100  may control the transceiver  106  to receive, from a second device through a physical sidelink control channel (PSCCH) based on a first SL resource, a first sidelink control information (SCI) for scheduling of a physical sidelink shared channel (PSSCH) and a second SCI. In addition, the processor  102  of the first device  100  may control the transceiver  106  to receive, from the second device through the PSSCH based on the first SL resource, the second SCI and data. For example, based on resource allocation information for a second SL resource being included in the first SCI, the first device may not monitor retransmission of the data from the second device in a time domain between the first SL resource and the second SL resource, and based on the resource allocation information for the second SL resource not being included in the first SCI, the HARQ RTT timer included in the SL DRX configuration may be started by the first device. 
     Based on an embodiment of the present disclosure, a first device configured to perform wireless communication may be provided. For example, the first device may comprise: one or more memories storing instructions; one or more transceivers; and one or more processors connected to the one or more memories and the one or more transceivers. For example, the one or more processors may execute the instructions to: obtain a sidelink (SL) discontinuous reception (DRX) configuration including information related to a timer for an active time and information related to a hybrid automatic repeat request (HARQ) round trip time (RTT) timer; start the timer for the active time; receive, from a second device through a physical sidelink control channel (PSCCH) based on a first SL resource, a first sidelink control information (SCI) for scheduling of a physical sidelink shared channel (PSSCH) and a second SCI; and receive, from the second device through the PSSCH based on the first SL resource, the second SCI and data. For example, based on resource allocation information for a second SL resource being included in the first SCI, the first device may not monitor retransmission of the data from the second device in a time domain between the first SL resource and the second SL resource, and based on the resource allocation information for the second SL resource not being included in the first SCI, the HARQ RTT timer included in the SL DRX configuration may be started by the first device. 
     Based on an embodiment of the present disclosure, an apparatus configured to control a first user equipment (UE) performing wireless communication may be provided. For example, the apparatus may comprise: one or more processors; and one or more memories operably connected to the one or more processors and storing instructions. For example, the one or more processors may execute the instructions to: obtain a sidelink (SL) discontinuous reception (DRX) configuration including information related to a timer for an active time and information related to a hybrid automatic repeat request (HARQ) round trip time (RTT) timer; start the timer for the active time; receive, from a second UE through a physical sidelink control channel (PSCCH) based on a first SL resource, a first sidelink control information (SCI) for scheduling of a physical sidelink shared channel (PSSCH) and a second SCI; and receive, from the second UE through the PSSCH based on the first SL resource, the second SCI and data. For example, based on resource allocation information for a second SL resource being included in the first SCI, the first UE may not monitor retransmission of the data from the second UE in a time domain between the first SL resource and the second SL resource, and based on the resource allocation information for the second SL resource not being included in the first SCI, the HARQ RTT timer included in the SL DRX configuration may be started by the first UE. 
     Based on an embodiment of the present disclosure, a non-transitory computer-readable storage medium storing instructions may be provided. For example, the non-transitory computer-readable storage medium storing instructions, when executed, may cause a first device to: obtain a sidelink (SL) discontinuous reception (DRX) configuration including information related to a timer for an active time and information related to a hybrid automatic repeat request (HARQ) round trip time (RTT) timer; start the timer for the active time; receive, from a second device through a physical sidelink control channel (PSCCH) based on a first SL resource, a first sidelink control information (SCI) for scheduling of a physical sidelink shared channel (PSSCH) and a second SCI; and receive, from the second device through the PSSCH based on the first SL resource, the second SCI and data. For example, based on resource allocation information for a second SL resource being included in the first SCI, the first device may not monitor retransmission of the data from the second device in a time domain between the first SL resource and the second SL resource, and based on the resource allocation information for the second SL resource not being included in the first SCI, the HARQ RTT timer included in the SL DRX configuration may be started by the first device. 
       FIG. 17  shows a method for a second device to perform wireless communication, based on an embodiment of the present disclosure. The embodiment of  FIG. 17  may be combined with various embodiments of the present disclosure. 
     Referring to  FIG. 17 , in step S 1710 , the second device may obtain a sidelink (SL) discontinuous reception (DRX) configuration including information related to a timer for an active time and information related to a hybrid automatic repeat request (HARQ) round trip time (RTT) timer. In step S 1720 , the second device may transmit, to a first device through a physical sidelink control channel (PSCCH) based on a first SL resource, a first sidelink control information (SCI) for scheduling of a physical sidelink shared channel (PSSCH) and a second SC. In step S 1730 , the second device may transmit, to the first device through the PSSCH based on the first SL resource, the second SCI and data. For example, based on resource allocation information for a second SL resource being included in the first SCI, retransmission of the data from the second device may not be monitored by the first device in a time domain between the first SL resource and the second SL resource, and based on the resource allocation information for the second SL resource not being included in the first SCI, the HARQ RTT timer included in the SL DRX configuration may be started by the first device. 
     The proposed method may be applied to the device(s) based on various embodiments of the present disclosure. First, the processor  202  of the second device  200  may obtain a sidelink (SL) discontinuous reception (DRX) configuration including information related to a timer for an active time and information related to a hybrid automatic repeat request (HARQ) round trip time (RTT) timer. In addition, the processor  202  of the second device  200  may control the transceiver  206  to transmit, to a first device through a physical sidelink control channel (PSCCH) based on a first SL resource, a first sidelink control information (SCI) for scheduling of a physical sidelink shared channel (PSSCH) and a second SC. In addition, the processor  202  of the second device  200  may control the transceiver  206  to transmit, to the first device through the PSSCH based on the first SL resource, the second SCI and data. For example, based on resource allocation information for a second SL resource being included in the first SCI, retransmission of the data from the second device may not be monitored by the first device in a time domain between the first SL resource and the second SL resource, and based on the resource allocation information for the second SL resource not being included in the first SCI, the HARQ RTT timer included in the SL DRX configuration may be started by the first device. 
     Based on an embodiment of the present disclosure, a second device configured to perform wireless communication may be provided. For example, the second device may comprise: one or more memories storing instructions; one or more transceivers; and one or more processors connected to the one or more memories and the one or more transceivers. For example, the one or more processors may execute the instructions to: obtain a sidelink (SL) discontinuous reception (DRX) configuration including information related to a timer for an active time and information related to a hybrid automatic repeat request (HARQ) round trip time (RTT) timer; transmit, to a first device through a physical sidelink control channel (PSCCH) based on a first SL resource, a first sidelink control information (SCI) for scheduling of a physical sidelink shared channel (PSSCH) and a second SCI; and transmit, to the first device through the PSSCH based on the first SL resource, the second SCI and data. For example, based on resource allocation information for a second SL resource being included in the first SCI, retransmission of the data from the second device may not be monitored by the first device in a time domain between the first SL resource and the second SL resource, and based on the resource allocation information for the second SL resource not being included in the first SCI, the HARQ RTT timer included in the SL DRX configuration may be started by the first device. 
     Based on an embodiment of the present disclosure, an apparatus configured to control a second user equipment (UE) performing wireless communication may be provided. For example, the apparatus may comprise: one or more processors; and one or more memories operably connected to the one or more processors and storing instructions. For example, the one or more processors may execute the instructions to: obtain a sidelink (SL) discontinuous reception (DRX) configuration including information related to a timer for an active time and information related to a hybrid automatic repeat request (HARQ) round trip time (RTT) timer; transmit, to a first UE through a physical sidelink control channel (PSCCH) based on a first SL resource, a first sidelink control information (SCI) for scheduling of a physical sidelink shared channel (PSSCH) and a second SCI; and transmit, to the first UE through the PSSCH based on the first SL resource, the second SCI and data. For example, based on resource allocation information for a second SL resource being included in the first SCI, retransmission of the data from the second UE may not be monitored by the first UE in a time domain between the first SL resource and the second SL resource, and based on the resource allocation information for the second SL resource not being included in the first SCI, the HARQ RTT timer included in the SL DRX configuration may be started by the first UE. 
     Based on an embodiment of the present disclosure, a non-transitory computer-readable storage medium storing instructions may be provided. For example, the non-transitory computer-readable storage medium storing instructions, when executed, may cause a second device to: obtain a sidelink (SL) discontinuous reception (DRX) configuration including information related to a timer for an active time and information related to a hybrid automatic repeat request (HARQ) round trip time (RTT) timer; transmit, to a first device through a physical sidelink control channel (PSCCH) based on a first SL resource, a first sidelink control information (SCI) for scheduling of a physical sidelink shared channel (PSSCH) and a second SCI; and transmit, to the first device through the PSSCH based on the first SL resource, the second SCI and data. For example, based on resource allocation information for a second SL resource being included in the first SCI, retransmission of the data from the second device may not be monitored by the first device in a time domain between the first SL resource and the second SL resource, and based on the resource allocation information for the second SL resource not being included in the first SCI, the HARQ RTT timer included in the SL DRX configuration may be started by the first device. 
     Various embodiments of the present disclosure may be combined with each other. 
     Hereinafter, device(s) to which various embodiments of the present disclosure can be applied will be described. 
     The various descriptions, functions, procedures, proposals, methods, and/or operational flowcharts of the present disclosure described in this document may be applied to, without being limited to, a variety of fields requiring wireless communication/connection (e.g., 5G) between devices. 
     Hereinafter, a description will be given in more detail with reference to the drawings. In the following drawings/description, the same reference symbols may denote the same or corresponding hardware blocks, software blocks, or functional blocks unless described otherwise. 
       FIG. 18  shows a communication system  1 , based on an embodiment of the present disclosure. The embodiment of  FIG. 18  may be combined with various embodiments of the present disclosure. 
     Referring to  FIG. 18 , a communication system  1  to which various embodiments of the present disclosure are applied includes wireless devices, Base Stations (BSs), and a network. Herein, the wireless devices represent devices performing communication using Radio Access Technology (RAT) (e.g., 5G New RAT (NR)) or Long-Term Evolution (LTE)) and may be referred to as communication/radio/5G devices. The wireless devices may include, without being limited to, a robot  100   a , vehicles  100   b - 1  and  100   b - 2 , an eXtended Reality (XR) device  100   c , a hand-held device  100   d , a home appliance  100   e , an Internet of Things (IoT) device  100   f , and an Artificial Intelligence (AI) device/server  400 . For example, the vehicles may include a vehicle having a wireless communication function, an autonomous vehicle, and a vehicle capable of performing communication between vehicles. Herein, the vehicles may include an Unmanned Aerial Vehicle (UAV) (e.g., a drone). 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) mounted in a vehicle, a television, a smartphone, a computer, a wearable device, a home appliance device, a digital signage, a vehicle, a robot, etc. The hand-held device may include a smartphone, a smartpad, a wearable device (e.g., a smartwatch or a smartglasses), and a computer (e.g., a notebook). The home appliance may include a TV, a refrigerator, and a washing machine. The IoT device may include a sensor and a smartmeter. For example, the BSs and the network may be implemented as wireless devices and a specific wireless device  200   a  may operate as a BS/network node with respect to other wireless devices. 
     Here, wireless communication technology implemented in wireless devices  100   a  to  100   f  of the present disclosure may include Narrowband Internet of Things for low-power communication in addition to LTE, NR, and 6G. In this case, for example, NB-IoT technology may be an example of Low Power Wide Area Network (LPWAN) technology and may be implemented as standards such as LTE Cat NB1, and/or LTE Cat NB2, and is not limited to the name described above. Additionally or alternatively, the wireless communication technology implemented in the wireless devices  100   a  to  100   f  of the present disclosure may perform communication based on LTE-M technology. In this case, as an example, the LTE-M technology may be an example of the LPWAN and may be called by various names including enhanced Machine Type Communication (eMTC), and the like. For example, the LTE-M technology may be implemented as at least any one of various standards such as 1) LTE CAT 0, 2) LTE Cat M1, 3) LTE Cat M2, 4) LTE non-Bandwidth Limited (non-BL), 5) LTE-MTC, 6) LTE Machine Type Communication, and/or 7) LTE M, and is not limited to the name described above. Additionally or alternatively, the wireless communication technology implemented in the wireless devices  100   a  to  100   f  of the present disclosure may include at least one of Bluetooth, Low Power Wide Area Network (LPWAN), and ZigBee considering the low-power communication, and is not limited to the name described above. As an example, the ZigBee technology may generate personal area networks (PAN) related to small/low-power digital communication based on various standards including IEEE 802.15.4, and the like, and may be called by various names. 
     The wireless devices  100   a  to  100   f  may be connected to the network  300  via the BSs  200 . An AI technology may be applied to the wireless devices  100   a  to  100   f  and the wireless devices  100   a  to  100   f  may be connected to the AI server  400  via the network  300 . The network  300  may be configured using a 3G network, a 4G (e.g., LTE) network, or a 5G (e.g., NR) network. Although the wireless devices  100   a  to  100   f  may communicate with each other through the BSs  200 /network  300 , the wireless devices  100   a  to  100   f  may perform direct communication (e.g., sidelink communication) with each other without passing through the BSs/network. For example, the vehicles  100   b - 1  and  100   b - 2  may perform direct communication (e.g. Vehicle-to-Vehicle (V2V)/Vehicle-to-everything (V2X) communication). The IoT device (e.g., a sensor) may perform direct communication with other IoT devices (e.g., sensors) or other wireless devices  100   a  to  100   f.    
     Wireless communication/connections  150   a ,  150   b , or  150   c  may be established between the wireless devices  100   a  to  100   f /BS  200 , or BS  200 /BS  200 . Herein, the wireless communication/connections may be established through various RATs (e.g., 5G NR) such as uplink/downlink communication  150   a , sidelink communication  150   b  (or, D2D communication), or inter BS communication (e.g. relay, Integrated Access Backhaul (IAB)). The wireless devices and the BSs/the wireless devices may transmit/receive radio signals to/from each other through the wireless communication/connections  150   a  and  150   b . For example, the wireless communication/connections  150   a  and  150   b  may transmit/receive signals through various physical channels. To this end, at least a part of various configuration information configuring processes, various signal processing processes (e.g., channel encoding/decoding, modulation/demodulation, and resource mapping/demapping), and resource allocating processes, for transmitting/receiving radio signals, may be performed based on the various proposals of the present disclosure. 
       FIG. 19  shows wireless devices, based on an embodiment of the present disclosure. The embodiment of  FIG. 19  may be combined with various embodiments of the present disclosure. 
     Referring to  FIG. 19 , a first wireless device  100  and a second wireless device  200  may transmit radio signals through a variety of RATs (e.g., LTE and NR). Herein, {the first wireless device  100  and the second wireless device  200 } may correspond to {the wireless device  100   x  and the BS  200 } and/or {the wireless device  100   x  and the wireless device  100   x } of  FIG. 18 . 
     The first wireless device  100  may include one or more processors  102  and one or more memories  104  and additionally further include one or more transceivers  106  and/or one or more antennas  108 . The processor(s)  102  may control the memory(s)  104  and/or the transceiver(s)  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(s)  102  may process information within the memory(s)  104  to generate first information/signals and then transmit radio signals including the first information/signals through the transceiver(s)  106 . The processor(s)  102  may receive radio signals including second information/signals through the transceiver  106  and then store information obtained by processing the second information/signals in the memory(s)  104 . The memory(s)  104  may be connected to the processor(s)  102  and may store a variety of information related to operations of the processor(s)  102 . For example, the memory(s)  104  may store software code including commands for performing a part or the entirety of processes controlled by the processor(s)  102  or for performing the descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed in this document. Herein, the processor(s)  102  and the memory(s)  104  may be a part of a communication modem/circuit/chip designed to implement RAT (e.g., LTE or NR). The transceiver(s)  106  may be connected to the processor(s)  102  and transmit and/or receive radio signals through one or more antennas  108 . Each of the transceiver(s)  106  may include a transmitter and/or a receiver. The transceiver(s)  106  may be interchangeably used with Radio Frequency (RF) unit(s). In the present disclosure, the wireless device may represent a communication modem/circuit/chip. 
     The second wireless device  200  may include one or more processors  202  and one or more memories  204  and additionally further include one or more transceivers  206  and/or one or more antennas  208 . The processor(s)  202  may control the memory(s)  204  and/or the transceiver(s)  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(s)  202  may process information within the memory(s)  204  to generate third information/signals and then transmit radio signals including the third information/signals through the transceiver(s)  206 . The processor(s)  202  may receive radio signals including fourth information/signals through the transceiver(s)  106  and then store information obtained by processing the fourth information/signals in the memory(s)  204 . The memory(s)  204  may be connected to the processor(s)  202  and may store a variety of information related to operations of the processor(s)  202 . For example, the memory(s)  204  may store software code including commands for performing a part or the entirety of processes controlled by the processor(s)  202  or for performing the descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed in this document. Herein, the processor(s)  202  and the memory(s)  204  may be a part of a communication modem/circuit/chip designed to implement RAT (e.g., LTE or NR). The transceiver(s)  206  may be connected to the processor(s)  202  and transmit and/or receive radio signals through one or more antennas  208 . Each of the transceiver(s)  206  may include a transmitter and/or a receiver. The transceiver(s)  206  may be interchangeably used with RF unit(s). In the present disclosure, the wireless device may represent a communication modem/circuit/chip. 
     Hereinafter, hardware elements of the wireless devices  100  and  200  will be described more specifically. One or more protocol layers may be implemented by, without being limited to, one or more processors  102  and  202 . For example, the one or more processors  102  and  202  may implement one or more layers (e.g., functional layers such as PHY, MAC, RLC, PDCP, RRC, and SDAP). The one or more processors  102  and  202  may generate one or more Protocol Data Units (PDUs) and/or one or more Service Data Unit (SDUs) according to the descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed in this document. The one or more processors  102  and  202  may generate messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed in this document. The one or more processors  102  and  202  may generate signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed in this document and provide the generated signals to the one or more transceivers  106  and  206 . The one or more processors  102  and  202  may receive the signals (e.g., baseband signals) from the one or more transceivers  106  and  206  and acquire the PDUs, SDUs, messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed in this document. 
     The one or more processors  102  and  202  may be referred to as controllers, microcontrollers, microprocessors, or microcomputers. The one or more processors  102  and  202  may be implemented by hardware, firmware, software, or a combination thereof. As an 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 the one or more processors  102  and  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 configured to include the modules, procedures, or functions. Firmware or software configured to perform the descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed in this document may be included in the one or more processors  102  and  202  or stored in the one or more memories  104  and  204  so as to be driven by the one or more processors  102  and  202 . The descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed in this document may be implemented using firmware or software in the form of code, commands, and/or a set of commands. 
     The one or more memories  104  and  204  may be connected to the one or more processors  102  and  202  and store various types of data, signals, messages, information, programs, code, instructions, and/or commands. The one or more memories  104  and  204  may be configured by Read-Only Memories (ROMs), Random Access Memories (RAMs), Electrically Erasable Programmable Read-Only Memories (EPROMs), flash memories, hard drives, registers, cash memories, computer-readable storage media, and/or combinations thereof. The one or more memories  104  and  204  may be located at the interior and/or exterior of the one or more processors  102  and  202 . The one or more memories  104  and  204  may be connected to the one or more processors  102  and  202  through various technologies such as wired or wireless connection. 
     The one or more transceivers  106  and  206  may transmit user data, control information, and/or radio signals/channels, mentioned in the methods and/or operational flowcharts of this document, to one or more other devices. The one or more transceivers  106  and  206  may receive user data, control information, and/or radio signals/channels, mentioned in the descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed in this document, from one or more other devices. For example, the one or more transceivers  106  and  206  may be connected to the one or more processors  102  and  202  and transmit and receive radio signals. For example, the one or more processors  102  and  202  may perform control so that the one or more transceivers  106  and  206  may transmit user data, control information, or radio signals to one or more other devices. The one or more processors  102  and  202  may perform control so that the one or more transceivers  106  and  206  may receive user data, control information, or radio signals from one or more other devices. The one or more transceivers  106  and  206  may be connected to the one or more antennas  108  and  208  and the one or more transceivers  106  and  206  may be configured to transmit and receive user data, control information, and/or radio signals/channels, mentioned in the descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed in this document, through the one or more antennas  108  and  208 . In this document, the one or more antennas may be a plurality of physical antennas or a plurality of logical antennas (e.g., antenna ports). The one or more transceivers  106  and  206  may convert received radio signals/channels etc. from RF band signals into baseband signals in order to process received user data, control information, radio signals/channels, etc. using the one or more processors  102  and  202 . The one or more transceivers  106  and  206  may convert the user data, control information, radio signals/channels, etc. processed using the one or more processors  102  and  202  from the base band signals into the RF band signals. To this end, the one or more transceivers  106  and  206  may include (analog) oscillators and/or filters. 
       FIG. 20  shows a signal process circuit for a transmission signal, based on an embodiment of the present disclosure. The embodiment of  FIG. 20  may be combined with various embodiments of the present disclosure. 
     Referring to  FIG. 20 , a signal processing circuit  1000  may include scramblers  1010 , modulators  1020 , a layer mapper  1030 , a precoder  1040 , resource mappers  1050 , and signal generators  1060 . An operation/function of  FIG. 20  may be performed, without being limited to, the processors  102  and  202  and/or the transceivers  106  and  206  of  FIG. 19 . Hardware elements of  FIG. 20  may be implemented by the processors  102  and  202  and/or the transceivers  106  and  206  of  FIG. 19 . For example, blocks  1010  to  1060  may be implemented by the processors  102  and  202  of  FIG. 19 . Alternatively, the blocks  1010  to  1050  may be implemented by the processors  102  and  202  of  FIG. 19  and the block  1060  may be implemented by the transceivers  106  and  206  of  FIG. 19 . 
     Codewords may be converted into radio signals via the signal processing circuit  1000  of  FIG. 20 . Herein, the codewords are encoded bit sequences of information blocks. The information blocks may include transport blocks (e.g., a UL-SCH transport block, a DL-SCH transport block). The radio signals may be transmitted through various physical channels (e.g., a PUSCH and a PDSCH). 
     Specifically, the codewords may be converted into scrambled bit sequences by the scramblers  1010 . Scramble sequences used for scrambling may be generated based on an initialization value, and the initialization value may include ID information of a wireless device. The scrambled bit sequences may be modulated to modulation symbol sequences by the modulators  1020 . A modulation scheme may include pi/2-Binary Phase Shift Keying (pi/2-BPSK), m-Phase Shift Keying (m-PSK), and m-Quadrature Amplitude Modulation (m-QAM). Complex modulation symbol sequences may be mapped to one or more transport layers by the layer mapper  1030 . Modulation symbols of each transport layer may be mapped (precoded) to corresponding antenna port(s) by the precoder  1040 . Outputs z of the precoder  1040  may be obtained by multiplying outputs y of the layer mapper  1030  by an N*M precoding matrix W. Herein, N is the number of antenna ports and M is the number of transport layers. The precoder  1040  may perform precoding after performing transform precoding (e.g., DFT) for complex modulation symbols. Alternatively, the precoder  1040  may perform precoding without performing transform precoding. 
     The resource mappers  1050  may map modulation symbols of each antenna port to time-frequency resources. The time-frequency resources may include a plurality of symbols (e.g., a CP-OFDMA symbols and DFT-s-OFDMA symbols) in the time domain and a plurality of subcarriers in the frequency domain. The signal generators  1060  may generate radio signals from the mapped modulation symbols and the generated radio signals may be transmitted to other devices through each antenna. For this purpose, the signal generators  1060  may include Inverse Fast Fourier Transform (IFFT) modules, Cyclic Prefix (CP) inserters, Digital-to-Analog Converters (DACs), and frequency up-converters. 
     Signal processing procedures for a signal received in the wireless device may be configured in a reverse manner of the signal processing procedures  1010  to  1060  of  FIG. 20 . For example, the wireless devices (e.g.,  100  and  200  of  FIG. 19 ) may receive radio signals from the exterior through the antenna ports/transceivers. The received radio signals may be converted into baseband signals through signal restorers. To this end, the signal restorers may include frequency downlink converters, Analog-to-Digital Converters (ADCs), CP remover, and Fast Fourier Transform (FFT) modules. Next, the baseband signals may be restored to codewords through a resource demapping procedure, a postcoding procedure, a demodulation processor, and a descrambling procedure. The codewords may be restored to original information blocks through decoding. Therefore, a signal processing circuit (not illustrated) for a reception signal may include signal restorers, resource demappers, a postcoder, demodulators, descramblers, and decoders. 
       FIG. 21  shows another example of a wireless device, based on an embodiment of the present disclosure. The wireless device may be implemented in various forms according to a use-case/service (refer to  FIG. 18 ). The embodiment of  FIG. 21  may be combined with various embodiments of the present disclosure. 
     Referring to  FIG. 21 , wireless devices  100  and  200  may correspond to the wireless devices  100  and  200  of  FIG. 19  and may be configured by various elements, components, units/portions, and/or modules. For example, each of the wireless devices  100  and  200  may include a communication unit  110 , a control unit  120 , a memory unit  130 , and additional components  140 . The communication unit may include a communication circuit  112  and transceiver(s)  114 . For example, the communication circuit  112  may include the one or more processors  102  and  202  and/or the one or more memories  104  and  204  of  FIG. 19 . For example, the transceiver(s)  114  may include the one or more transceivers  106  and  206  and/or the one or more antennas  108  and  208  of  FIG. 19 . The control unit  120  is electrically connected to the communication unit  110 , the memory  130 , and the additional components  140  and controls overall operation of the wireless devices. For example, the control unit  120  may control an electric/mechanical operation of the wireless device based on programs/code/commands/information stored in the memory unit  130 . The control unit  120  may transmit the information stored in the memory unit  130  to the exterior (e.g., other communication devices) via the communication unit  110  through a wireless/wired interface or store, in the memory unit  130 , information received through the wireless/wired interface from the exterior (e.g., other communication devices) via the communication unit  110 . 
     The additional components  140  may be variously configured according to types of wireless devices. For example, the additional components  140  may include at least one of a power unit/battery, input/output (I/O) unit, a driving unit, and a computing unit. The wireless device may be implemented in the form of, without being limited to, the robot ( 100   a  of  FIG. 18 ), the vehicles ( 100   b - 1  and  100   b - 2  of  FIG. 18 ), the XR device ( 100   c  of  FIG. 18 ), the hand-held device ( 100   d  of  FIG. 18 ), the home appliance ( 100   e  of  FIG. 18 ), the IoT device ( 100   f  of  FIG. 18 ), a digital broadcast terminal, a hologram device, a public safety device, an MTC device, a medicine device, a fintech device (or a finance device), a security device, a climate/environment device, the AI server/device ( 400  of  FIG. 18 ), the BSs ( 200  of  FIG. 18 ), a network node, etc. The wireless device may be used in a mobile or fixed place according to a use-example/service. 
     In  FIG. 21 , the entirety of the various elements, components, units/portions, and/or modules in the wireless devices  100  and  200  may be connected to each other through a wired interface or at least a part thereof may be wirelessly connected through the communication unit  110 . For example, in each of the wireless devices  100  and  200 , the control unit  120  and the communication unit  110  may be connected by wire and the control unit  120  and first units (e.g.,  130  and  140 ) may be wirelessly connected through the communication unit  110 . Each element, component, unit/portion, and/or module within the wireless devices  100  and  200  may further include one or more elements. For example, the control unit  120  may be configured by a set of one or more processors. As an example, the control unit  120  may be configured by a set of a communication control processor, an application processor, an Electronic Control Unit (ECU), a graphical processing unit, and a memory control processor. As another example, the memory  130  may be configured by 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. 
     Hereinafter, an example of implementing  FIG. 21  will be described in detail with reference to the drawings. 
       FIG. 22  shows a hand-held device, based on an embodiment of the present disclosure. The hand-held device may include a smartphone, a smartpad, a wearable device (e.g., a smartwatch or a smartglasses), or a portable computer (e.g., a notebook). The hand-held 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. 22  may be combined with various embodiments of the present disclosure. 
     Referring to  FIG. 22 , a hand-held device  100  may include an antenna unit  108 , a communication unit  110 , a control unit  120 , a memory unit  130 , a power supply unit  140   a , an interface unit  140   b , and an I/O unit  140   c . The antenna unit  108  may be configured as a part of the communication unit  110 . Blocks  110  to  130 / 140   a  to  140   c  correspond to the blocks  110  to  130 / 140  of  FIG. 21 , respectively. 
     The communication unit  110  may transmit and receive signals (e.g., data and control signals) to and from other wireless devices or BSs. The control unit  120  may perform various operations by controlling constituent elements of the hand-held device  100 . The control unit  120  may include an Application Processor (AP). The memory unit  130  may store data/parameters/programs/code/commands needed to drive the hand-held device  100 . The memory unit  130  may store input/output data/information. The power supply unit  140   a  may supply power to the hand-held device  100  and include a wired/wireless charging circuit, a battery, etc. The interface unit  140   b  may support connection of the hand-held device  100  to other external devices. The interface unit  140   b  may include various ports (e.g., an audio I/O port and a video I/O port) for connection with external devices. The I/O unit  140   c  may input or output video information/signals, audio information/signals, data, and/or information input by a user. The I/O unit  140   c  may include a camera, a microphone, a user input unit, a display unit  140   d , a speaker, and/or a haptic module. 
     As an example, in the case of data communication, the I/O unit  140   c  may acquire information/signals (e.g., touch, text, voice, images, or video) input by a user and the acquired information/signals may be stored in the memory unit  130 . The communication unit  110  may convert the information/signals stored in the memory into radio signals and transmit the converted radio signals to other wireless devices directly or to a BS. The communication unit  110  may receive radio signals from other wireless devices or the BS and then restore the received radio signals into original information/signals. The restored information/signals may be stored in the memory unit  130  and may be output as various types (e.g., text, voice, images, video, or haptic) through the I/O unit  140   c.    
       FIG. 23  shows a vehicle or an autonomous vehicle, based on an embodiment of the present disclosure. The vehicle or autonomous vehicle may be implemented by a mobile robot, a car, a train, a manned/unmanned Aerial Vehicle (AV), a ship, etc. The embodiment of  FIG. 23  may be combined with various embodiments of the present disclosure. 
     Referring to  FIG. 23 , a vehicle or autonomous vehicle  100  may include an antenna unit  108 , a communication unit  110 , a control unit  120 , a driving unit  140   a , a power supply unit  140   b , a sensor unit  140   c , and an autonomous driving unit  140   d . The antenna unit  108  may be configured as a part of the communication unit  110 . The blocks  110 / 130 / 140   a  to  140   d  correspond to the blocks  110 / 130 / 140  of  FIG. 21 , respectively. 
     The communication unit  110  may transmit and receive signals (e.g., data and control signals) to and from external devices such as other vehicles, BSs (e.g., gNBs and road side units), and servers. The control unit  120  may perform various operations by controlling elements of the vehicle or the autonomous vehicle  100 . The control unit  120  may include an Electronic Control Unit (ECU). The driving unit  140   a  may cause the vehicle or the autonomous vehicle  100  to drive on a road. The driving unit  140   a  may include an engine, a motor, a powertrain, a wheel, a brake, a steering device, etc. The power supply unit  140   b  may supply power to the vehicle or the autonomous vehicle  100  and include a wired/wireless charging circuit, a battery, etc. The sensor unit  140   c  may acquire a vehicle state, ambient environment information, user information, etc. The sensor unit  140   c  may include an Inertial Measurement Unit (IMU) sensor, a collision sensor, a wheel sensor, a speed sensor, a slope sensor, a weight 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 illumination sensor, a pedal position sensor, etc. The autonomous driving unit  140   d  may implement technology for maintaining a lane on which a vehicle is driving, technology for automatically adjusting speed, such as adaptive cruise control, technology for autonomously driving along a determined path, technology for driving by automatically setting a path if a destination is set, and the like. 
     For example, the communication unit  110  may receive map data, traffic information data, etc. from an external server. The autonomous driving unit  140   d  may generate an autonomous driving path and a driving plan from the obtained data. The control unit  120  may control the driving unit  140   a  such that the vehicle or the autonomous vehicle  100  may move along the autonomous driving path according to the driving plan (e.g., speed/direction control). In the middle of autonomous driving, the communication unit  110  may aperiodically/periodically acquire recent traffic information data from the external server and acquire surrounding traffic information data from neighboring vehicles. In the middle of autonomous driving, the sensor unit  140   c  may obtain a vehicle state and/or surrounding environment information. The autonomous driving unit  140   d  may update the autonomous driving path and the driving plan based on the newly obtained data/information. The communication unit  110  may transfer information about a vehicle position, the autonomous driving path, and/or the driving plan to the external server. The external server may predict traffic information data using AI technology, etc., based on the information collected from vehicles or autonomous vehicles and provide the predicted traffic information data to the vehicles or the autonomous vehicles. 
     Claims in the present description can be combined in a various way. For instance, technical features in method claims of the present description can be combined to be implemented or performed in an apparatus, and technical features in apparatus claims can be combined to be implemented or performed in a method. Further, technical features in method claim(s) and apparatus claim(s) can be combined to be implemented or performed in an apparatus. Further, technical features in method claim(s) and apparatus claim(s) can be combined to be implemented or performed in a method.