Patent Publication Number: US-2023164770-A1

Title: Method and apparatus for performing sl drx operation in nr v2x

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of International Application No. PCT/KR2022/007072, filed on May 17, 2022, which claims the benefit of earlier filing date and right of priority to Korean Patent Application Nos. 10-2021-0063554, filed on May 17, 2021, 10-2021-0064115, filed on May 18, 2021, the contents of which are hereby incorporated by reference herein in their entireties. 
    
    
     FIELD 
     This disclosure relates to a wireless communication system. 
     BACKGROUND 
     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, for example, when configured to enable HARQ feedback, a TX UE configured to groupcast may receive NACK information or ACK information from at least one RX UE in the group. For example, the TX UE may determine that the SL DRX HARQ RTT timer of the RX UE is to be started based on an arbitrary point in time when NACK information is received from at least one RX UE. For example, when NACK only HARQ feedback is configured for the cast type of groupcast, TX UE may be determine that the SL DRX HARQ RTT timer of the RX UE is started, based on an arbitrary time when it is expected to complete an acknowledgment (ACK) information of the at least one RX UE from at least one RX UE or, or based on an arbitrary time when transmission of the ACK is expected to be skipped. For example, misalignment between the SL DRX timer of the TX UE and the SL DRX timer of the RX UE(s) may occur. 
     Technical Solutions 
     According to an embodiment of the present disclosure, a method for performing wireless communication by a first device may be proposed. For example, the first device may obtain an SL DRX configuration including information related to a sidelink (SL) discontinuous reception (DRX) timer. For example, the first device may receive a first SCI for scheduling of second sidelink control information (SCI) and a physical sidelink shared channel (PSSCH) from a second device through a physical sidelink control channel (PSCCH). For example, the first device may receive the second SCI related to a groupcast and medium access control (MAC) protocol data unit (PDU) from the second device through the PSSCH. For example, the first device may determine a physical sidelink feedback channel (PSFCH) resource based on an index of a sub-channel related to the PSSCH and an index of a slot. For example, the first device may, based on the second SCI being related to the groupcast, and information representing whether SL hybrid automatic repeat request (HARQ) feedback is enabled included in the second SCI being configured to be enabled, start the SL DRX timer after the PSFCH resource. 
     According to an embodiment of the present disclosure, a first device for performing wireless communication may be proposed. For example, the first device may include one or more memories storing instructions; one or more transceivers; and one or more processors operably connected to the one or more memories and the one or more transceivers, and the one or more processors may execute the instructions to: obtain an SL DRX configuration including information related to a sidelink (SL) discontinuous reception (DRX) timer. For example, the one or more processors may execute the instructions to: receive a first SCI for scheduling of second sidelink control information (SCI) and a physical sidelink shared channel (PSSCH) from a second device through a physical sidelink control channel (PSCCH). For example, the one or more processors may execute the instructions to: receive the second SCI related to a groupcast and medium access control (MAC) protocol data unit (PDU) from the second device through the PSSCH. For example, the one or more processors may execute the instructions to: determine a physical sidelink feedback channel (PSFCH) resource based on an index of a sub-channel related to the PSSCH and an index of a slot. For example, the one or more processors may execute the instructions to: based on the second SCI being related to the groupcast, and information representing whether SL hybrid automatic repeat request (HARQ) feedback is enabled included in the second SCI being configured to be enabled, start the SL DRX timer after the PSFCH resource. 
     According to an embodiment of the present disclosure, an device configured to control a first UE may be proposed. For example, the device may comprise: one or more processors; and one or more memories operably connected to the one or more processors and storing instructions, and the one or more processors may execute the instructions to: obtain an SL DRX configuration including information related to a sidelink (SL) discontinuous reception (DRX) timer. For example, the one or more processors may execute the instructions to: receive a first SCI for scheduling of second sidelink control information (SCI) and a physical sidelink shared channel (PSSCH) from a second UE through a physical sidelink control channel (PSCCH). For example, the one or more processors may execute the instructions to: receive the second SCI related to a groupcast and medium access control (MAC) protocol data unit (PDU) from the second UE through the PSSCH. For example, the one or more processors may execute the instructions to: determine a physical sidelink feedback channel (PSFCH) resource based on an index of a sub-channel related to the PSSCH and an index of a slot. For example, the one or more processors may execute the instructions to: based on the second SCI being related to the groupcast, and information representing whether SL hybrid automatic repeat request (HARQ) feedback is enabled included in the second SCI being configured to be enabled, start the SL DRX timer after the PSFCH resource. 
     According to an embodiment of the present disclosure, a non-transitory computer-readable storage medium storing instructions may be proposed. For example, the instructions, when executed, may cause a first device to: obtain an SL DRX configuration including information related to a sidelink (SL) discontinuous reception (DRX) timer. For example, the instructions, when executed, may cause a first device to: receive a first SCI for scheduling of second sidelink control information (SCI) and a physical sidelink shared channel (PSSCH) from a second UE through a physical sidelink control channel (PSCCH). For example, the instructions, when executed, may cause a first device to: receive the second SCI related to a groupcast and medium access control (MAC) protocol data unit (PDU) from the second UE through the PSSCH. For example, the instructions, when executed, may cause a first device to: determine a physical sidelink feedback channel (PSFCH) resource based on an index of a sub-channel related to the PSSCH and an index of a slot. For example, the instructions, when executed, may cause a first device to: based on the second SCI being related to the groupcast, and information representing whether SL hybrid automatic repeat request (HARQ) feedback is enabled included in the second SCI being configured to be enabled, start the SL DRX timer after the PSFCH resource. 
     According to an embodiment of the present disclosure, a method for performing wireless communication by a second device may be proposed. For example, the second device may obtain an SL DRX configuration including information related to a sidelink (SL) discontinuous reception (DRX) timer. For example, the second device may transmit a first SCI for scheduling of second sidelink control information (SCI) and a physical sidelink shared channel (PSSCH) to a first device through a physical sidelink control channel (PSCCH). For example, the second device may transmit the second SCI related to a groupcast and medium access control (MAC) protocol data unit (PDU) to the first device through the PSSCH. For example, the second device may, based on the second SCI being related to the groupcast, and information representing whether SL hybrid automatic repeat request (HARQ) feedback is enabled included in the second SCI being configured to be enabled, start the SL DRX timer after the PSFCH resource. 
     According to an embodiment of the present disclosure, a second device for performing wireless communication may be proposed. For example, the second device may include one or more memories storing instructions; one or more transceivers; and one or more processors operably connected to the one or more memories and the one or more transceivers, and the one or more processors may execute the instructions to: obtain an SL DRX configuration including information related to a sidelink (SL) discontinuous reception (DRX) timer. For example, the one or more processors may execute the instructions to: transmit a first SCI for scheduling of second sidelink control information (SCI) and a physical sidelink shared channel (PSSCH) to a first device through a physical sidelink control channel (PSCCH). For example, the one or more processors may execute the instructions to: transmit the second SCI related to a groupcast and medium access control (MAC) protocol data unit (PDU) to the first device through the PSSCH. For example, the one or more processors may execute the instructions to: based on the second SCI being related to the groupcast, and information representing whether SL hybrid automatic repeat request (HARQ) feedback is enabled included in the second SCI being configured to be enabled, start the SL DRX timer after the PSFCH resource. 
     According to an embodiment of the present disclosure, an apparatus configured to control a second UE may be proposed. 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, and the one or more processors may execute the instructions to: obtain an SL DRX configuration including information related to a sidelink (SL) discontinuous reception (DRX) timer. For example, the one or more processors may execute the instructions to: transmit a first SCI for scheduling of second sidelink control information (SCI) and a physical sidelink shared channel (PSSCH) to a first UE through a physical sidelink control channel (PSCCH). For example, the one or more processors may execute the instructions to: transmit the second SCI related to a groupcast and medium access control (MAC) protocol data unit (PDU) to the first UE through the PSSCH. For example, the one or more processors may execute the instructions to: based on the second SCI being related to the groupcast, and information representing whether SL hybrid automatic repeat request (HARQ) feedback is enabled included in the second SCI being configured to be enabled, start the SL DRX timer after the PSFCH resource. 
     According to an embodiment of the present disclosure, a non-transitory computer-readable storage medium storing instructions may be proposed. For example, the instructions, when executed, may cause a second device to: obtain an SL DRX configuration including information related to a sidelink (SL) discontinuous reception (DRX) timer. For example, the instructions, when executed, may cause a second device to: transmit a first SCI for scheduling of second sidelink control information (SCI) and a physical sidelink shared channel (PSSCH) to a first device through a physical sidelink control channel (PSCCH). For example, the instructions, when executed, may cause a second device to: transmit the second SCI related to a groupcast and medium. access control (MAC) protocol data unit (PDU) to the first device through the PSSCH. For example, the instructions, when executed, may cause a second device to: based on the second SCI being related to the groupcast, and information representing whether SL hybrid automatic repeat request (HARQ) feedback is enabled included in the second SCI being configured to be enabled, start, by the second device, the SL DRX timer after the PSFCH resource. 
     Effects of the Disclosure 
     A UE can efficiently perform sidelink communication. 
    
    
     
       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 figure for explaining a problem of a method for a UE to perform an SL DRX operation, based on an embodiment of the present disclosure. 
         FIG.  9    is a figure for explaining a method in which a UE performs an SL DRX operation, according to an embodiment of the present disclosure. 
         FIG.  10    is a figure for explaining a procedure for a UE to perform an SL DRX operation according to an embodiment of the present disclosure. 
         FIG.  11    is a figure for explaining a method of operating an SL DRX timer in a groupcast NACK only mode according to an embodiment of the present disclosure. 
         FIG.  12    is a figure for explaining a method of operating an SL DRX timer in a groupcast NACK only mode according to an embodiment of the present disclosure. 
         FIG.  13    is a figure for explaining a method of operating an SL DRX timer in a groupcast NACK only mode according to an embodiment of the present disclosure. 
         FIG.  14    is a figure for explaining an operation of an SL DRX timer (e.g., SL DRX inactivity timer, SL DRX HARQ RTT timer) in groupcast according to an embodiment of the present disclosure. 
         FIG.  15    is a figure for explaining an operation of an SL DRX timer (e.g., SL DRX inactivity timer, SL DRX HARQ RTT timer) in groupcast according to an embodiment of the present disclosure. 
         FIG.  16    shows a method for a first device to perform wireless communication, according to an embodiment of the present disclosure. 
         FIG.  17    shows a method for a second device to perform wireless communication according to 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 802.16 m 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 (Nslotsymb), a number slots per frame (Nframe,uslot), and a number of slots per subframe (Nsubframe,uslot) based on an SCS configuration (u), in a case where a normal CP is used.  
     
       
         
          TABLE  1 

           
               
               
               
               
             
               
                 SCS (15*2 U ) 
                 N slots   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 designation 
                 Corresponding 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 mat 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 designation 
                 Corresponding 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 an SL channel or an 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 NstartBWP from the point A, and a bandwidth NsizeBWP. 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 an 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 1st-stage SCI) to a second UE based on the resource scheduling. In step S 620 , the first UE may transmit a PSSCH (e.g., 2nd-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. 
     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 1st-stage SCI) to a second UE by using the resource(s). In step S 620 , the first UE may transmit a PSSCH (e.g., 2nd-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 1st SCI, a first SCI, a 1st-stage SCI or a 1st-stage SCI format, and a SCI transmitted through a PSSCH may be referred to as a 2nd SCI, a second SCI, a 2nd-stage SCI or a 2nd-stage SCI format. For example, the 1st-stage SCI format may include a SCI format 1-A, and the 2nd-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-BetaOffsets2ndSCI   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, in accordance with an embodiment of the present disclosure. The embodiment of  FIG.  7    may be combined with various embodiments of the present disclosure. 
     Specifically,  FIG.  7 ( a )  shows broadcast-type SL communication,  FIG.  7 ( b )  shows unicast type-SL communication, and  FIG.  7 ( c )  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 NPSSCHsubch 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′kSL (0 ≤ k &lt; T′max) has a PSFCH transmission occasion resource if k mod NPSFCHPSSCH = 0, where t′kSL 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 NPSFCHPSSCH 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 MPSFCHPRB,set PRBs in a resource pool for PSFCH transmission in a PRB of the resource pool. For a number of Nsubch 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 NPSFCHPSSCH, the UE allocates the [(i+j·NPSFCHPSSCH) ·MPSFCHsubch,slot, (i+1+j·NPSFCHPSSCH)·MPSFCHsubch,slot-1] PRBs from the MPRB,setPSFCH PRBs to slot i among the PSSCH slots associated with the PSFCH slot and sub-channel j, where MPSFCHsubch,slot = MPSFCHPRB,set / (Nsubch·NPSFCHPSSCH), 0 ≤ i &lt; NPSFCHPSSCH, 0 ≤j &lt; Nsubch, and the allocation starts in an ascending order of i and continues in an ascending order of j. The UE expects that MPSFCHPRB,set is a multiple of Nsubch·NPSFCHPSSCH. 
     A UE determines a number of PSFCH resources available for multiplexing HARQ-ACK information in a PSFCH transmission as RPSFCHPRB,CS = NPSFCHtype·MPSFCHsubch,slot·NPSFCHCS where NPSFCHCS is a number of cyclic shift pairs for the resource pool and, based on an indication by higher layers, 
     NPSFCHtype = 1 and the MPSFCHsubch,slot PRBs are associated with the starting sub-channel of the corresponding PSSCH   NPSFCHtype = NPSSCHsubch and the NPSSCHsubch·MPSFCHsubch,slot PRBs are associated with one or more sub-channels from the NPSSCHsubch sub-channels of the corresponding PSSCH   

     The PSFCH resources are first indexed according to an ascending order of the PRB index, from the NPSFCHtype ·MPSFCHsubch,slot PRBs, and then according to an ascending order of the cyclic shift pair index from the NPSFCHCS cyclic shift pairs. 
     A UE determines an index of a PSFCH resource for a PSFCH transmission in response to a PSSCH reception as (PID + MID) mod RPSFCHPRB,CS where PID is a physical layer source ID provided by SCI format 2-A or 2-B scheduling the PSSCH reception, and MID 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, MID is zero. 
     A UE determines a m0 value, for computing a value of cyclic shift α, from a cyclic shift pair index corresponding to a PSFCH resource index and from NPSFCHCS using Table 8.  
     
       
         
          TABLE 8
           
               
               
               
               
               
               
               
             
               
                 N 
                   
                   
                   
                 m 0 
 
                   
                   
               
               
                 PSFCH CS 
 
                 cycli 
                 cycli 
                 cycli 
                 cycli 
                 cycli 
                 cycli 
               
               
                   
                 c shift pair 
                 c shift pair 
                 c shift pair 
                 c shift pair 
                 c shift pair 
                 c shift pair 
               
               
                   
                 index 0 
                 index 1 
                 index 2 
                 index 3 
                 index 4 
                 index 5 
               
             
            
               
                 1 
                 0 
                 - 
                 - 
                 - 
                 - 
                 - 
               
               
                 2 
                 0 
                 3 
                 - 
                 - 
                 - 
                 - 
               
               
                 3 
                 0 
                 2 
                 4 
                 - 
                 - 
                 - 
               
               
                 6 
                 0 
                 1 
                 2 
                 3 
                 4 
                 5 
               
            
           
         
       
     
     A UE determines a mcs 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 
               
            
           
         
       
     
     Hereinafter, a procedure for a UE to report HARQ-ACK in an uplink will be described. 
     For reporting HARQ-ACK information generated by a UE based on HARQ-ACK information obtained by the UE from a PSFCH reception or from an absence of PSFCH reception, the UE may be provided with a PUCCH resource or a PUSCH resource. A UE reports HARQ-ACK information for a primary cell of a PUCCH group among cells in which the UE monitors a PDCCH for detection of DCI format 3_0. 
     For type 1 or type 2 SL configuration grant PSSCH transmission by a UE within a time period provided by sl-PeriodCG, the UE generates HARQ-ACK information in response to PSFCH reception in order to multiplex within a PUCCH transmission occasion after the last time resource in a set of time resources. 
     For each PSFCH reception opportunity among PSFCH reception opportunities, the UE generates HARQ-ACK information to be reported during PUCCH or PUSCH transmission. A UE may be indicated in SCI format to do one of the following, and a UE configures a HARQ-ACK codeword using HARQ-ACK information if applicable. Here, as one of the following for a UE to perform:
     if a UE receives a PSFCH related to SCI format 2-A having a cast type indicator field value of “10”,
   the UE generates HARQ-ACK information with the same value as the HARQ-ACK information value determined when the UE receives a PSFCH within a PSFCH reception opportunity, and generates a NACK if it is determined that a PSFCH is not received within a PSFCH reception opportunity.   
   if a UE receives a PSFCH related to SCI format 2-A in which a cast type indicator field value is “01”,
   among PSFCH resources corresponding to all ID M ID s of a plurality of UEs expected to receive a PSSCH, the UE generates an ACK when determining an ACK among at least one PSFCH reception opportunity among the number of PSFCH reception opportunities; otherwise, the UE generates a NACK   
   if a UE receives a PSFCH related to SCI format 2-B or SCI format 2-A having a cast type indicator field value of “11”,
   when a UE determines an absence of PSFCH reception for each PSFCH reception opportunity among reception opportunities of PSFCH, the UE generate an ACK; otherwise, the UE generate a NACK.   
   

     After a UE transmits a PSSCH and receives a PSFCH in response to a PSFCH resource opportunity, a priority value of HARQ-ACK information is the same as a priority value of a PSSCH transmission related to a PSFCH reception opportunity providing HARQ-ACK information. 
     When a PSFCH is not received at any PSFCH reception opportunity related to PSSCH transmission within a resource provided by DCI format 3_0 including a CRC scrambled by SL-RNTI, due to prioritization, or if a UE is provided with PUCCH resources for reporting HARQ-ACK information within resources provided within a single period for a configured grant, a UE generates a NACK. A priority value of a NACK is the same as a priority value of a PSSCH that is not transmitted due to a prioritization. 
     If a UE does not transmit a PSCCH including an SCI format 1-A for scheduling a PSSCH among any of resources provided by a configured grant within a single period, and the UE is provided with a PUCCH resource for reporting HARQ-ACK information, the UE generates an ACK. A priority value of ACK is equal to the largest priority value among possible priority values for a configuration grant. 
     After the end of the last symbol of the last PSFCH reception opportunity, to report HARQ-ACK information that starts earlier than (N+1)*(2048+144)*κ*2 µ *T c , a UE does not expect to be provided with a PUCCH resource or a PUSCH resource among several PSFCH reception opportunities in which the UE generates HARQ-ACK information reported during PUCCH or PUSCH transmission.
     µ=min(µ SL ,µ UL ), where µ SL  is an SCS setting of an SL BWP and µ UL  is an SCS setting of an active UL BWP of a primary cell.   N is determined from µ according to Table 11.   

     
       
         
          TABLE 11
           
               
               
             
               
                 µ 
                 N 
               
             
            
               
                 0 
                 14 
               
               
                 1 
                 18 
               
               
                 2 
                 28 
               
               
                 3t 
                 32 
               
            
           
         
       
     
     For the number of PSFCH reception opportunities that are related to PUCCH transmission and end with n slots, a UE provides HARQ-ACK information generated during PUCCH transmission within n+k slots according to overlapping conditions. Here, k is the number of slots indicated by a PSFCH-to-HARQfeedback timing indicator field (if present) among DCI formats indicating a slot related to PUCCH transmission to report HARQ-ACK information, or here, k may be provided by sl-PSFCH-ToPUCCH-CG-Type1-r16. Assuming that the start of a sidelink frame is the same as the start of a downlink frame, k=0 corresponds to the last slot for PUCCH transmission overlapping with the last PSFCH reception opportunity. 
     In the case of PSSCH transmission by a UE scheduled by a DCI format or in the case of type 2 PSSCH transmission of an SL configuration grant activated by a DCI format, in the DCI format, a PUCCH resource indicator field is 0, and when a value of a PSFCH-to-HARQ feedback timing indicator field (if present) is 0, it indicates to a UE that a PUCCH resource is not provided. Regarding transmission of Type 1 PSSCH of SL configured grant, a PUCCH resource may be provided by sl-N1PUCCH-AN-r16 and sl-PSFCH-ToPUCCH-CG-Type1-r16. If a PUCCH resource is not provided, a UE does not transmit a PUCCH including HARQ-ACK information generated from among a plurality of PSFCH reception opportunities. 
     In the case of PUCCH transmission including HARQ-ACK information, a UE determines a PUCCH resource set for the HARQ-ACK information bit and then determines a PUCCH resource. PUCCH resource determination has a PSFCH-to-HARQfeedback timing indicator field value indicating the same slot for PUCCH transmission, the UE detects it, and is based on a PUCCH resource indicator field for the last DCI format 3_0, among DCI format 3_0s related to transmitting the corresponding HARQ-ACK information in a PUCCH in which a DCI format detected by a UE for PUCCH resource determination is indexed in ascending order over PDCCH monitoring occasion indexes. 
     A UE does not expect to multiplex HARQ-ACK information about one or more SL configuration grants among the same PUCCH. 
     A priority value of PUCCH transmission including one or more sidelink HARQ-ACK information bits is a minimum priority value for one or more HARQ-ACK information bits. Hereinafter, a CRC for DCI format 3_0 is scrambled to SL-RNTI or SL-CS-RNTI. 
     An SL DRX configuration referred to in this disclosure may include at least one or more of the following parameters. 
     For example, an SL DRX configuration may include one or more of the information listed below. 
     (1) For example, SL drx-onDurationTimer may be information on the duration at the beginning of a DRX Cycle. For example, a start period of a DRX cycle may be information on a period in which a terminal operates in an active mode to transmit or receive sidelink data. 
     (2) For example, SL drx-SlotOffset may be information on a delay before starting a drx-onDurationTimer of a DRX-on duration timer. 
     (3) For example, SL drx-InactivityTimer may be information on the duration after the PSCCH occasion in which a PSCCH indicates a new sidelink transmission and reception for the MAC entity. For example, when a transmitting terminal instructs PSSCH transmission through a PSCCH, the transmitting terminal operates in an active mode while an SL drx-InactivityTimer is running, so that the transmitting terminal may transmit PSSCH to a receiving terminal. Also, for example, when a receiving terminal is instructed that a transmitting terminal transmits a PSSCH through PSCCH reception, the receiving terminal operates in an active mode while SL drx-InactivityTimer is running, so that the receiving terminal may receive the PSSCH from the transmitting terminal. 
     (4) For example, SL drx-RetransmissionTimer may be information on the maximum duration until a retransmission is received. For example, SL drx-RetransmissionTimer may be configured per HARQ process. 
     (5) For example, SL drx-HARQ-RTT-Timer may be information on the minimum duration before an assignment for HARQ retransmission is expected by the MAC entity. For example, SL drx-HARQ-RTT-Timer may be configured per HARQ process. 
     (6) For example, SL drx-LongCycleStartOffset may be information on the Long DRX cycle and drx-StartOffset which defines the subframe where the Long and Short DRX Cycle starts. 
     (7) For example, SL drx-ShortCycle may be information on the Short DRX cycle. For example, SL drx-ShortCycle may be optional information. 
     (8) For example, SL drx-ShortCycleTimer may be information on the duration a UE shall follow the Short DRX cycle. For example, SL drx-ShortCycleTimer may be optional information. 
     The following SL DRX timer mentioned in this disclosure may be used for the following purposes. 
     (1) SL DRX on-duration timer: A period in which a UE performing an SL DRX operation should basically operate in an active time to receive a counterpart UE’s PSCCH/PSSCH. 
     (2) SL DRX inactivity timer: A period in which a UE performing an SL DRX operation extends an SL DRX on-duration period, which is a period in which an active time is basically required to receive PSCCH/PSSCH of a counterpart UE. 
     For example, a UE may extend an SL DRX on-duration timer by an SL DRX inactivity timer period. Also, when a UE receives a new packet (e.g., new PSSCH transmission) from a counterpart UE, the UE may start an SL DRX inactivity timer to extend the SL DRX on-duration timer. 
     For example, an SL DRX inactivity timer may be used to extend an SL DRX duration timer period, which is a period in which an RX UE performing an SL DRX operation should basically operate as an active time to receive a PSCCH/PSSCH of the other TX UE. That is, an SL DRX on-duration timer may be extended by an SL DRX inactivity timer period. In addition, when an RX UE receives a new packet (e.g., new PSSCH transmission) from a counterpart TX UE, the RX UE may start an SL DRX inactivity timer to extend the SL DRX on-duration timer. 
     (3) SL DRX HARQ RTT timer: A period in which a UE performing an SL DRX operation operates in a sleep mode until it receives a retransmission packet (or PSSCH assignment) transmitted by a counterpart UE. 
     For example, when a UE starts an SL DRX HARQ RTT timer, the UE may determine that a counterpart UE will not transmit a sidelink retransmission packet to it until the SL DRX HARQ RTT timer expires, and may operate in a sleep mode while the corresponding timer is running. For example, when a UE starts an SL DRX HARQ RTT timer, the UE may not monitor sidelink retransmission packets from a counterpart UE until the SL DRX HARQ RTT timer expires. For example, when an RX UE that has received a PSCCH/PSSCH transmitted by a TX UE transmits SL HARQ NACK feedback, the RX UE may start an SL DRX HARQ RTT timer. In this case, an RX UE may determine that a counterpart TX UE will not transmit a sidelink retransmission packet to it until an 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: A timer that starts when an SL DRX HARQ RTT timer expires, and a period in which a UE performing SL DRX operation operates as an active time to receive a retransmission packet (or PSSCH assignment) transmitted by a counterpart UE. 
     For example, during the corresponding timer period, a UE may receive or monitor a retransmission sidelink packet (or PSSCH assignment) transmitted by a counterpart UE. For example, an RX UE may receive or monitor a retransmission sidelink packet (or PSSCH assignment) transmitted by a counterpart TX UE while an SL DRX retransmission timer is running. 
     The following Uu DRX timer mentioned in this disclosure may be used for the following purposes. 
     Uu DRX HARQ RTT TimerSL 
     For example, Uu DRX HARQ RTT TimerSL may be used in a period in which a UE performing Uu DRX operation does not need to monitor DCI (PDCCH) for SL Mode 1 operation transmitted by a base station. That is, while a Uu DRX HARQ RTT TimerSL is running, a UE may not need to monitor a PDCCH for an SL Mode 1 operation. 
     Uu DRX Retransmission TimerSL 
     For example, it may be used in a period in which a UE performing Uu DRX operation monitors DCI (PDCCH) for SL Mode 1 operation transmitted by a base station. That is, while a Uu DRX Retransmission TimerSL is running, a UE may monitor a PDCCH transmitted by a base station for an SL Mode 1 operation. 
     In the present disclosure, names of timers (Sidelink DRX Onduration Timer, Sidelink DRX Inactivity Timer, Sidelink DRX HARQ RTT Timer, Sidelink DRX Retransmission Timer, Uu DRX HARQ RTT TimerSL, Uu DRX Retransmission TimerSL, etc.) are exemplary, and timers that perform the same/similar functions based on content described in each timer may be regarded as the same/similar timers regardless of their names. 
       FIG.  8    is a figure for explaining a problem of a method for a UE to perform an SL DRX operation, based on an embodiment of the present disclosure. The embodiment of  FIG.  8    may be combined with various embodiments of the present disclosure. 
     Referring to  FIG.  8   , according to an embodiment of the present disclosure, a TX UE may perform new transmission or retransmission to an RX UE (e.g., RX UE1, RX UE2, or RX UE3). For example, when HARQ feedback is configured to enable and when NACK only HARQ feedback is configured for the cast type of groupcast, HARQ feedback information regarding whether the RX UE successfully decodes the data on the TB can be received/monitored by the TX UE. until a certain time. For example, when configured to enable HARQ feedback and when NACK only HARQ feedback is configured, the RX UE may transmit NACK information when it fails to successfully decode data on TB, and when it successfully decodes data on TB, ACK information may not be transmitted (e.g., transmission may be omitted). 
     For example, if RX UE ½ fails to decode the PSCCH/PSSCH transmitted by the TX UE, RX UE ½ transmits a NACK at the PSFCH resource location allocated by the TX UE and starts the SL DRX HARQ RTT timer. In addition, when RX UE ½ expires the SL DRX HARQ RTT timer, RX UE ½ starts the SL DRX Retransmission timer, and RX UE ½ monitor retransmission packets transmitted by the TX UE until the timer expires. When the TX UE also receives a NACK from RX UE ½, the TX UE starts the SL DRX HARQ RTT timer at the PSFCH resource location of the RX UE½, and when the SL DRX HARQ RTT timer expires, the TX UE starts the SL DRX Retransmission timer, the TX UE assumes that the RX UE ½ will monitor the retransmission packet while the SL DRX Retransmission Timer is running. Therefore, it is possible for the TX UE to accurately determine the start position of the SL DRX Retransmission timer operated by RX UE ½, so TX UE can transmit a retransmission packet in the time duration during which the SL DRX Retransmission timer of the RX UE ½, started and operated by RX UE ½, is running. 
     However, if RX UE 3 succeeds in decoding the PSSCH/PSSCH transmitted by the TX UE (ACK), RX UE 3 does not transmit an ACK at the PSFCH resource location. This is because HARQ feedback is transmitted on the PSFCH resource only in the case of NACK in NACK only mode. 
     Only the operation of starting the SL DRX HARQ RTT timer may be supported when the RX UE actually transmitted ACK or NACK, and the operation of starting the SL HARQ RTT timer when the RX UE did not actually transmit HARQ ACK or NACK may not supported. In addition, after the TX UE transmits PSCCH/PSSCH to the RX UE in group cast NACK only mode, if the TX UE does not receive PSFCH (ACK or NACK), the TX UE cannot determine whether the RX UE did not to transmit ACK due to the positive ACK, or whether the RX UE did not transmit HARQ Feedback (ACK or NACK) because discontinuous transmission (DTX) occurred. 
     Therefore, in groupcast NACK only mode, if TX UE does not receive PSFCH (NACK) from RX UE, TX UE cannot figure out at all when RX UE starts HARQ RTT timer, and when RX UE’s SL DRX HARQ RTT timer expires, and when the SL DRX Retransmission timer of the RX UE starts. For example, if RX UE 3 successfully receives PSSCH/PSSCH from TX UE, RX UE 3 does not transmit PSFCH (ACK), and when RX UE 3 does not transmit PSFCH (ACK), since RX UE 3 did not define the start position of RX UE3’s SL DRX HARQ RTT timer, if TX UE does not receive PSFCH from RX UE 3, since there is no way to guess when RX UE 3’s SL DRX HARQ RTT Timer expires and RX UE 3’s SL DRX Retransmission timer is started, the TX UE cannot transmit an SL TB (e.g. another new initial TB) to RX UE 3 within the active time of RX UE 3 (e.g., SL DRX Retransmission timer). 
       FIG.  9    is a figure for explaining a method in which a UE performs an SL DRX operation, according to an embodiment of the present disclosure. The embodiment of  FIG.  9    may be combined with various embodiments of the present disclosure. 
     Referring to  FIG.  9   , in an embodiment of the present disclosure, when the TX UE transmits a HARQ Feedback Enabled MAC PDU to the RX UE in groupcast NACK only mode, and the RX UE successfully receives the PSCCH / PSSCH from the TX UE (ACK), the time when the RX UE starts the SL DRX HARQ RTT timer may be defined as the location of the PSFCH resource. For example, even if the TX UE does not receive the PSFCH from the RX UE, TX UE can figure out what’s going on when the TX UE starts the SL DRX HARQ RTT timer, when the SL DRX HARQ RTT timer expires, and when the SL DRX retransmission timer runs. Through this, for example, in an embodiment of the present disclosure, even if the TX UE does not receive the PSFCH from the RX UE, the TX UE can determine when the RX UE runs (starts) the SL DRX Retransmission timer (active time). For example, an embodiment of the present disclosure may allow a TX UE to transmit an SL TB (e..g, new initial TB) within an active time of the RX UE. 
     Referring to  FIG.  9   , in an embodiment of the present disclosure, when the TX UE transmits a HARQ Feedback Enabled MAC PDU to the RX UE in groupcast NACK only mode, and the RX UE successfully receives the PSCCH / PSSCH from the TX UE In case of failure (NACK) (e.g., when the MAC PDU is not successfully decoded, when it is not received due to discontinuous transmission (DTX), etc.), (TX UE and/or) _RX UE sets the SL DRX HARQ RTT timer The start time may be defined as the location of the PSFCH resource. For example, regardless of whether the TX UE received the PSFCH from the RX UE, when the TX UE initiates the SL DRX HARQ RTT timer, when the SL DRX HARQ RTT timer expires, and when the SL DRX Retransmission You can make it possible to determine whether the timer is running. Through this, for example, an embodiment of the present disclosure can help the TX UE to figure out when the RX UE drives (starts) the SL DRX Retransmission timer (active time), regardless of whether the TX UE receives the PSFCH from the RX UE. For example, an embodiment of the present disclosure may enable a TX UE to transmit a retransmission packet within an active time of an RX UE. 
     An embodiment of the present disclosure may have various effects. For example, according to an embodiment of the present disclosure, the start time of the SL DRX timer of RX UEs (e.g., RX UEs in a group) may be aligned regardless of reception failure or decoding failure of the RX UE. For example, by at least one RX UE in the same group starting the SL DRX timer on the PSFCH regardless of trasnmitting or not transmitting HARQ ACK information to the TX UE, the timing of the SL DRX timer operation of at least one RX UE in the same group may be aligned. can For example, by aligning the timing of the SL DRX timer operation of at least one RX UE in the same group, confusion about the transmission operation of the TX UE according to the NACK only mode can be prevented. For example, since the timing of the SL DRX timer operation of at least one RX UE in the same group is aligned, the timing of the groupcast New TB to be transmitted by the TX UE may not be left to any implementation of the TX UE. For example, the reception of the RX UE for the (re)transmission packet transmitted by the TX UE may be successful. For example, the TX UE’s reception of the NACK information transmitted by the RX UE may also be successful. For example, even if the TX UE does not receive HARQ Feedback (ACK) of the RX UE, the TX UE can predict when the SL DRX timer of the RX UE operates. For example, the TX UE may not unnecessarily transmit a (re)transmission packet within the inactive time of all RX UEs, and the (re)transmission packet may not be wasted. 
       FIG.  10    is a figure for explaining a procedure for a UE to perform an SL DRX operation according to 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   , for example, a TX UE may transmit an SL DRX configuration including information about an SL DRX timer of an RX UE (e.g., at least one RX UE in a group) through a PC5-RRC connection, to the RX UE (S 1010 ). For example, the RX UE may receive a second sidelink control information (SCI) and a first SCI for scheduling of a physical sidelink shared channel (PSSCH) from the TX UE through a physical sidelink control channel (PSCCH) (S 1020 ). For example, the RX UE may receive SCI including resource information (e.g., information on reserved transmission resource(s)) from the TX UE. For example, the RX UE may receive the second SCI related to groupcast and a medium access control (MAC) protocol data unit (PDU) from the TX UE through the PSSCH (S 1022 ). For example, the TX UE and/or the RX UE may determine a physical sidelink feedback channel (PSFCH) resource based on a sub-channel index and a slot index related to the PSSCH (S 1030 ). For example, the RX UE may determine that the second SCI is related to the groupcast. For example, the RX UE may determine that information representing whether SL hybrid automatic repeat request (HARQ) feedback included in the second SCI is enabled is configured to enable HARQ feedback. For example, if the MAC PDU (e.g., data) received by the RX UE is not successfully decoded (S 1050 ), the RX UE is after PSFCH resources and before starting/triggering the SL DRX HARQ RTT timer, SL HARQ NACK information may be transmitted to the TX UE. For example, if the MAC PDU (e.g., data) received by the RX UE is successfully decoded (S 1050 ), the RX UE may start/trigger the SL DRX timer after the PSFCH resource. For example, if the MAC PDU (e.g., data) received by the RX UE is successfully decoded (S 1050 ), the RX UE may not transmit SL HARQ ACK information to the TX UE (e.g., may skip transmission), and may start / trigger the SL DRX timer after the PSFCH resource. For example, if the MAC PDU (e.g., data) received by the RX UE is not successfully decoded (S 1050 ), the RX UE may start/trigger the SL DRX timer after the PSFCH resource (S 1054 ). 
     According to an embodiment of the present disclosure, a sidelink DRX timer (e.g., SL DRX HARQ RTT timer, Sidelink DRX inactivity timer) interlocked with groupcast sidelink transmission and sidelink reception may be operated. 
       FIG.  11    is a figure for explaining a method of operating an SL DRX timer in a groupcast NACK only mode according to 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   , according to an embodiment of the present disclosure, for example, in case of sidelink groupcast NACK only mode (e.g., no RX UE feedback to TX UE when ACK (acknowledge), only RX UE feedback to TX UE when NACK(negative acknowledge)), Sidelink DRX timer (e.g., SL DRX HARQ RTT timer, SL DRX inactivity timer) may be operated. For example, the UE (e.g., TX UE and RX UE) may restart an SL DRX timer (e.g., SL DRX HARQ RTT timer, SL DRX inactivity timer, SL DRX retransmission timer) for each PSFCH resource location indicated by the SCI. For example, in a sidelink groupcast communication mode in which feedback is transmitted to the TX UE only in the case of NACK (negative acknowledge) and in which no feedback is transmitted to the TX UE in case of ACK, the UE (e.g., TX UE and RX UE) may restart SL DRX timers (e.g., SL DRX HARQ RTT timer, SL DRX inactivity timer, SL DRX retransmission timer) for each PSFCH resource location indicated by SCI. 
       FIG.  12    is a figure for explaining a method of operating an SL DRX timer in a groupcast NACK only mode according to 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   , according to an embodiment of the present disclosure, for example, UEs (TX UE and RX UE) may restart an SL DRX timer (e.g., SL DRX HARQ RTT timer, SL DRX inactivity timer, SL DRX retransmission timer)) for each PSFCH resource location indicated by SCI. For example, if the TX UE does not receive any feedback from the RX UE(s)(s) belonging to the group, the TX UE may determine all as ACKs. For example, if the TX UE does not receive any feedback from the RX UE(s)(s) belonging to the group, (the TX UE determines that all are ACKs), based on the SL DRX timer of the RX UE (e.g., SL DRX HARQ RTT timer, SL DRX inactivity timer, SL DRX retransmission timer) that has not expired, and the first started SL DRX timer (e.g., SL DRX HARQ RTT timer, SL DRX inactivity timer and SL DRX retransmission timer), the TX UE may transmit a groupcast new transport block (New TB) only until the timer expires. 
       FIG.  13    is a figure for explaining a method of operating an SL DRX timer in a groupcast NACK only mode according to 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   , according to an embodiment of the present disclosure, for example, UEs (TX UE and RX UE) may restart an SL DRX timer (e.g., SL DRX HARQ RTT timer, SL DRX inactivity timer, SL DRX retransmission timer) for each PSFCH resource location indicated by SCI. For example, if the TX UE does not receive any feedback from the RX UE(s)(s) belonging to the group, the TX UE may determine all as ACKs. For example, if the TX UE does not receive any feedback from the RX UE(s)(s) belonging to the group, (the TX UE determines that all are ACKs), based on the SL DRX timer of the RX UE (e.g., SL DRX HARQ RTT timer, SL DRX inactivity timer, SL DRX retransmission timer) that has not expired and the most recently started (latest started), the TX UE may transmit a groupcast new transport block (New TB) only until the timer expires. 
     The operation of the present disclosure may be a solution that can be extended/applied to sidelink broadcast (or unicast) operation. 
     The timer operation mentioned in this disclosure is a solution that can be commonly applied to all of the following sidelink DRX timer operations.
     SL DRX timer (e.g., a timer that allows the UE to operate in inactive time or active time during the timer period).   For example, Sidelink DRX HARQ RTT timer or Sidelink DRX inactive time related timer, Sidelink DRX on-duration timer, Sidelink DRX inactive timer DRX Inactivity timer, Sidelink DRX Retransmission Timer, or Sidelink DRX active time related timer.   

     An embodiment of the present disclosure may have various effects. For example, by running the SL DRX timer on the PSFCH, whether or not at least one RX UE s HARQ ACK information to the TX UE, the SL DRX operation timings of the RX UEs in the same group can be aligned. For example, by aligning the timing of the SL DRX operation of the RX UE, confusion about the (re)transmission operation of the TX UE to the RX UE according to the NACK only mode can be prevented. For example, by aligning the SL DRX operation timing of the RX UE, the groupcast New TB (or retransmission packet) that the TX UE intends to transmit may not be wasted. For example, since the timing of the SL DRX operation of the RX UE is aligned, the timing of the groupcast New TB (or retransmission packet) to be transmitted by the TX UE may not be left to any implementation of the TX UE. 
     According to an embodiment of the present disclosure, SL DRX operation may be supported in NR V2X. For example, SL DRX timer (eg, SL DRX inactivity timer, SL DRX HARQ RTT timer) operation may be supported in sidelink groupcast in NR V2X. In the embodiment (s) of the present disclosure, a sidelink DRX timer (e.g., SL DRX inactivity timer, SL DRX HARQ RTT timer) interlocked with groupcast sidelink transmission and sidelink reception can be operated. 
       FIG.  14    is a figure for explaining an operation of an SL DRX timer (e.g., SL DRX inactivity timer, SL DRX HARQ RTT timer) in groupcast according to 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   , according to an embodiment of the present disclosure, for example, when a TX UE receives an ACK from at least one RX UE belonging to a groupcast group, (eg, Alternatively, when receiving a NACK, or when a new transport block (TB) is transmitted, etc.), the TX UE may start the SL DRX groupcast inactivity timer of the TX UE. For example, if a TX UE has a new transport block (TB) to be transmitted in a groupcast, the TX UE transmits a new TB (transport block) before the SL DRX inactivity timer started by the TX UE expires. block) can be transmitted. For example, even if the TX UE receives an ACK for the retransmission TB or a NACK for the retransmission TB, the TX UE does not restart the SL DRX groupcast inactivity timer on the TX UE side.  FIG.  14    may be an example related to an embodiment of the present disclosure. 
       FIG.  15    is a figure for explaining an operation of an SL DRX timer (e.g., SL DRX inactivity timer, SL DRX HARQ RTT timer) in groupcast according to an embodiment of the present disclosure. The embodiment of  FIG.  15    may be combined with various embodiments of the present disclosure. 
     Referring to  FIG.  15   , according to an embodiment of the present disclosure, for example, when a TX UE receives ACK information from at least one RX UE belonging to a groupcast group, (e.g., or NACK information is received , or when a new transport block (new TB (transport block) is transmitted, etc.), the TX UE may start the SL DRX groupcast timer (e.g., SL DRX groupcast inactivity timer) of the TX UE, and the RX UE may start the RX The UE’s SL DRX groupcast HARQ RTT timer). For example, when the TX UE receives ACK information for the retransmission TB or NACK information for the retransmission TB, the TX UE may restart the SL DRX groupcast inactivity timer for groupcast of the TX UE. And, if there is a new transport block (new TB) to be transmitted in the groupcast, the TX UE may be allowed to transmit the new TB before the SL DRX inactivity timer started by the TX UE expires. For example, in the present disclosure, the following operation of the RX UE may be proposed. For example, even if it is determined by the RX UE that an acknowledgment (ACK) is received for the received new TB, in order to help guarantee the transmission of a new transport block (new TB) of the TX UE to another RX UE (e.g. a RX UE that has not received a physical sidelink control channel (PSCCH)/physical sidelink shared channel (PSSCH) because of discontinuous transmission (DTX), etc.), the RX UE may report the decoding result of the retransmission TB to the TX UE, and the RX UE may restart its own SL DRX inactivity timer. (e.g., RX UE 1 in  FIG.  15   ). For example, an RX UE may align with the end point (e.g., length, or restart point, etc.) of an SL DRX timer (e.g., SL DRX groupcast inactivity timer (SL DRX inactivity timer for groupcast, RX UE’s SL DRX HARQ RTT timer)) for another RX UE (e.g., an RX UE that fails to receive a physical sidelink control channel (PSCCH)/physical sidelink shared channel (PSSCH) due to discontinuous detection (DTX), etc.). In addition, the RX UE can monitor the new transport block (new TB) transmitted by the TX UE until the same expiration time as the other RX UEs. For example, according to an embodiment of the present disclosure, there may be an effect of the inactivity timer period of the TX UE being extended, and helping an RX UE of which the inactivity timer may not be started by discontinuous detection (DTX) to receive a retransmission TB transmitted by a TX UE. 
     The operation of the present disclosure may be a solution that can be extended/applied to sidelink broadcast (or unicast) operation. 
     The proposal of the present disclosure can be applied and extended to a method for solving a problem in which loss occurs due to an interruption occurring during Uu BWP switching. In addition, the proposal of the present disclosure can be applied and extended to a method to solve the problem of loss due to interruption occurring during SL BWP switching when (e.g., a plurality of) SL BWPs are supported for the UE. 
     The proposal of the present disclosure may be extended and applied to parameters (e.g., timers) included in UE-pair specific SL DRX configuration, UE-pair specific SL DRX pattern, or UE-pair specific SL DRX configuration, in addition to parameters (e.g. timers) included in default/common SL DRX configuration, default/common SL DRX patterns, or default/common SL DRX configuration. In addition, an on-duration mentioned in the proposal of the present disclosure can be extended and interpreted as an active time period (e.g., time to wake-up state (e.g., RF module turned on) to receive/transmit radio signals), an off-duration may be extended and interpreted as a sleep time (e.g., a time for operating in a sleep mode state (e.g., a state in which an RF module is turned off) for power saving). It does not mean that a TX UE is obligated to operate in a sleep mode in a sleep time interval. If necessary, a TX UE may be allowed to operate in an active time for a while for a sensing operation and/or a transmission operation even in sleep time. 
     For example, whether the (part of) proposed method/rule of the present disclosure is applied and/or a related parameter (e.g., threshold) may be configured specifically (or differently or independently) for a resource pool. For example, whether the (part of) proposed method/rule of the present disclosure is applied and/or a related parameter (e.g., threshold) may be configured specifically (or differently or independently) for congestion level. For example, whether the (part of) proposed method/rule of the present disclosure is applied and/or a related parameter (e.g., threshold) may be configured specifically (or differently or independently) for a priority of a service. For example, whether the (part of) proposed method/rule of the present disclosure is applied and/or a related parameter (e.g., threshold) may be configured specifically (or differently or independently) for a service type. For example, whether the (part of) proposed method/rule of the present disclosure is applied and/or a related parameter (e.g., threshold) may be configured specifically (or differently or independently) for a QoS requirement (e.g., latency, reliability). For example, whether the (part of) proposed method/rule of the present disclosure is applied and/or a related parameter (e.g., threshold) may be configured specifically (or differently or independently) for PQI(5QI(5G QoS identifier) for PC5). For example, whether the (part of) proposed method/rule of the present disclosure is applied and/or a related parameter (e.g., threshold) may be configured specifically (or differently or independently) for a traffic type (e.g., a periodic generation or a aperiodic generation). For example, whether the (part of) proposed method/rule of the present disclosure is applied and/or a related parameter (e.g., threshold) may be configured specifically (or differently or independently) for an SL transmission resource allocation mode (e.g., mode 1 or mode 2). 
     For example, whether the proposed rule of the present disclosure is applied and/or related parameter setting values may be configured specifically (or differently or independently) for a resource pool. For example, whether the proposed rule of the present disclosure is applied and/or related parameter setting values may be configured specifically (or differently or independently) for a type of service/packet. For example, whether the proposed rule of the present disclosure is applied and/or related parameter setting values may be configured specifically (or differently or independently) for a priority of service/packet. For example, whether the proposed rule of the present disclosure is applied and/or related parameter setting values may be configured specifically (or differently or independently) for QoS requirements (e.g., URLLC/EMBB traffic, reliability, latency). For example, whether the proposed rule of the present disclosure is applied and/or related parameter setting values may be configured specifically (or differently or independently) for PQI. For example, whether the proposed rule of the present disclosure is applied and/or related parameter setting values may be configured specifically (or differently or independently) for a cast type (e.g., unicast, groupcast, broadcast). For example, whether the proposed rule of the present disclosure is applied and/or related parameter setting values may be configured specifically (or differently or independently) for (resource pool) congestion level (e.g., CBR). For example, whether the proposed rule of the present disclosure is applied and/or related parameter setting values may be configured specifically (or differently or independently) for SL HARQ feedback scheme (e.g., NACK-only feedback, ACK/NACK feedback). For example, whether the proposed rule of the present disclosure is applied and/or related parameter setting values may be configured specifically (or differently or independently) for HARQ Feedback Enabled MAC PDU transmission. For example, whether the proposed rule of the present disclosure is applied and/or related parameter setting values may be configured specifically (or differently or independently) for HARQ Feedback Disabled MAC PDU transmission. For example, whether the proposed rule of the present disclosure is applied and/or related parameter setting values may be configured specifically (or differently or independently) for whether PUCCH-based SL HARQ feedback reporting operation is set. For example, whether the proposed rule of the present disclosure is applied and/or related parameter setting values may be configured specifically (or differently or independently) for a resource reselection based on pre-emption or pre-emption. For example, whether the proposed rule of the present disclosure is applied and/or related parameter setting values may be configured specifically (or differently or independently) for a re-evaluation or re-selection of resources based on re-evaluation. For example, whether the proposed rule of the present disclosure is applied and/or related parameter setting values may be configured specifically (or differently or independently) for (L2 or L1) (source and/or destination) identifier. For example, whether the proposed rule of the present disclosure is applied and/or related parameter setting values may be configured specifically (or differently or independently) for (L2 or L1) (Combination of Source ID and Destination ID) Identifier. For example, whether the proposed rule of the present disclosure is applied and/or related parameter setting values may be configured specifically (or differently or independently) for (L2 or L1) (a combination of source ID and destination ID pair and cast type) identifier. For example, whether the proposed rule of the present disclosure is applied and/or related parameter setting values may be configured specifically (or differently or independently) for the direction of a pair of source layer ID and destination layer ID. For example, whether the proposed rule of the present disclosure is applied and/or related parameter setting values may be configured specifically (or differently or independently) for PC5 RRC connection/link. For example, whether the proposed rule of the present disclosure is applied and/or related parameter setting values may be configured specifically (or differently or independently) for the case of performing SL DRX. For example, whether the proposed rule of the present disclosure is applied and/or related parameter setting values may be configured specifically (or differently or independently) for SL mode type (e.g., resource allocation mode 1 or resource allocation mode 2). For example, whether the proposed rule of the present disclosure is applied and/or related parameter setting values may be configured specifically (or differently or independently) for a case of performing (a)periodic resource reservation. 
     The certain time referred to in the proposal of the present disclosure may refer to a time during which a UE operates as an active time for a predefined time in order to receive a sidelink signal or sidelink data from a counterpart UE. A certain time referred to in the proposal of the present disclosure may refer to a time during which a UE operates as an active time for a specific timer (e.g., a sidelink DRX retransmission timer, a sidelink DRX inactivity timer, or a timer that guarantees operation as active time in DRX operation of an RX UE) time in order to receive a sidelink signal or sidelink data from a counterpart UE. In addition, whether the proposal and proposal rule of the present disclosure are applied (and/or related parameter setting values) may also be applied to mmWave SL operation. 
       FIG.  16    shows a method for a first device to perform wireless communication, according to 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 an SL DRX configuration including information related to a sidelink (SL) discontinuous reception (DRX) timer. in step S 1620 , the first device may receive a first SCI for scheduling of second sidelink control information (SCI) and a physical sidelink shared channel (PSSCH) from a second device through a physical sidelink control channel (PSCCH). in step S 1630 , the first device may receive the second SCI related to a groupcast and medium access control (MAC) protocol data unit (PDU) from the second device through the PSSCH. in step S 1640 , the first device may determine a physical sidelink feedback channel (PSFCH) resource based on an index of a sub-channel related to the PSSCH and an index of a slot. in step S 1650 , the first device may, based on the second SCI being related to the groupcast, and information representing whether SL hybrid automatic repeat request (HARQ) feedback is enabled included in the second SCI being configured to be enabled, start the SL DRX timer after the PSFCH resource. 
     Additionally or alternatively, the second SCI may include cast type information representing a NACK-only groupcast cast type. 
     Additionally or alternatively, the second SCI may be an SCI to support NACK (negative acknowledge)-only feedback, but not to support positive-negative acknowledgment (ACK) feedback. 
     Additionally or alternatively, the second SCI may further include information regarding a zone ID. 
     Additionally or alternatively, the second SCI may further include information regarding a communication range requirement. 
     Additionally or alternatively, the SL HARQ feedback may include negative acknowledge (NACK) information. 
     Additionally or alternatively, the SL HARQ feedback may not include positive acknowledge (ACK) information. 
     Additionally or alternatively, the SL DRX timer may include a SL DRX HARQ roundtrip time (RTT) timer. 
     Additionally or alternatively, based on the information representing whether the SL HARQ feedback is enabled, included in the second SCI related with the groupcast, being configured to HARQ feedback enabled, and the MAC PDU being successfully decoded, the SL DRX timer may be started after the PSFCH resource. 
     Additionally or alternatively, based on the information representing whether the SL HARQ feedback is enabled, included in the second SCI related with the groupcast, being configured to HARQ feedback enabled, the MAC PDU being successfully decoded, and the SL HARQ feedback being not transmitted to the second device on the PSFCH resource, the SL DRX timer may be started after the PSFCH resource. 
     Additionally or alternatively, wherein based on the information representing whether the SL HARQ feedback is enabled being configured to HARQ feedback enabled, the MAC PDU being successfully decoded, and the SL HARQ feedback to the second device being skipped on the PSFCH resource, the SL DRX timer may be started after the PSFCH resource. 
     Additionally or alternatively, based on the information representing whether the SL HARQ feedback is enabled being configured to HARQ feedback enabled, the MAC PDU being successfully decoded, and the SL HARQ feedback being not transmitted to the second device on the PSFCH resource, the SL DRX timer may be started after the PSFCH resource. 
     Additionally or alternatively, wherein based on the information representing whether the SL HARQ feedback is enabled being configured to HARQ feedback enabled, the MAC PDU being successfully decoded, and the SL HARQ feedback to the second device being skipped on the PSFCH resource, the SL DRX timer may be started after the PSFCH resource. 
     Additionally or alternatively, the SL HARQ feedback may be positive-ACK information. 
     Additionally or alternatively, the PSFCH resource may be a resource for which the SL HARQ feedback is transmitted. 
     Additionally or alternatively, the SL DRX timer may be started after an end of a time domain of the PSFCH resource. 
     Additionally or alternatively, the SL DRX timer may be started in a first slot after the end of the time domain of the PSFCH resource. 
     Additionally or alternatively, based on the information representing whether the SL HARQ feedback is enabled being configured to HARQ feedback enabled, and the MAC PDU not being successfully decoded, the SL DRX timer may be started after the PSFCH resource. 
     Additionally or alternatively, based on the information representing whether the SL HARQ feedback is enabled being configured to HARQ feedback enabled, the MAC PDU not being successfully decoded, and the SL HARQ feedback being transmitted to the second device on the PSFCH resource, the SL DRX timer may be started after the PSFCH resource. 
     The proposed method may be applied to an apparatus according to various embodiments of the present disclosure. First, a processor  102  of a first apparatus  100  may obtain an SL DRX configuration including information related to a sidelink (SL) discontinuous reception (DRX) timer. And, a processor  102  of a first apparatus  100 , may control a tranceiver  106  to: receive a first SCI for scheduling of second sidelink control information (SCI) and a physical sidelink shared channel (PSSCH) from a second device through a physical sidelink control channel (PSCCH). And, a processor  102  of a first apparatus  100 , may control a tranceiver  106  to: receive the second SCI related to a groupcast and medium access control (MAC) protocol data unit (PDU) from the second device through the PSSCH. And, a processor  102  of a first apparatus  100 , may determine a physical sidelink feedback channel (PSFCH) resource based on an index of a sub-channel related to the PSSCH and an index of a slot. a processor  102  of a first apparatus  100  may, based on the second SCI being related to the groupcast, and information representing whether SL hybrid automatic repeat request (HARQ) feedback is enabled included in the second SCI being configured to be enabled, start the SL DRX timer after the PSFCH resource. 
     According to an embodiment of the present disclosure, a first device for performing wireless communication may be proposed. For example, the first device may include one or more memories storing instructions; one or more transceivers; and one or more processors operably connected to the one or more memories and the one or more transceivers, and the one or more processors may execute the instructions to: obtain an SL DRX configuration including information related to a sidelink (SL) discontinuous reception (DRX) timer. For example, the one or more processors may execute the instructions to: receive a first SCI for scheduling of second sidelink control information (SCI) and a physical sidelink shared channel (PSSCH) from a second device through a physical sidelink control channel (PSCCH). For example, the one or more processors may execute the instructions to: receive the second SCI related to a groupcast and medium access control (MAC) protocol data unit (PDU) from the second device through the PSSCH. For example, the one or more processors may execute the instructions to: determine a physical sidelink feedback channel (PSFCH) resource based on an index of a sub-channel related to the PSSCH and an index of a slot. For example, the one or more processors may execute the instructions to: based on the second SCI being related to the groupcast, and information representing whether SL hybrid automatic repeat request (HARQ) feedback is enabled included in the second SCI being configured to be enabled, start the SL DRX timer after the PSFCH resource. 
     According to an embodiment of the present disclosure, an device configured to control a first UE may be proposed. For example, the device may comprise: one or more processors; and one or more memories operably connected to the one or more processors and storing instructions, and the one or more processors may execute the instructions to: obtain an SL DRX configuration including information related to a sidelink (SL) discontinuous reception (DRX) timer. For example, the one or more processors may execute the instructions to: receive a first SCI for scheduling of second sidelink control information (SCI) and a physical sidelink shared channel (PSSCH) from a second UE through a physical sidelink control channel (PSCCH). For example, the one or more processors may execute the instructions to: receive the second SCI related to a groupcast and medium access control (MAC) protocol data unit (PDU) from the second UE through the PSSCH. For example, the one or more processors may execute the instructions to: determine a physical sidelink feedback channel (PSFCH) resource based on an index of a sub-channel related to the PSSCH and an index of a slot. For example, the one or more processors may execute the instructions to: based on the second SCI being related to the groupcast, and information representing whether SL hybrid automatic repeat request (HARQ) feedback is enabled included in the second SCI being configured to be enabled, start the SL DRX timer after the PSFCH resource. 
     According to an embodiment of the present disclosure, a non-transitory computer-readable storage medium storing instructions may be proposed. For example, the instructions, when executed, may cause a first device to: obtain an SL DRX configuration including information related to a sidelink (SL) discontinuous reception (DRX) timer. For example, the instructions, when executed, may cause a first device to: receive a first SCI for scheduling of second sidelink control information (SCI) and a physical sidelink shared channel (PSSCH) from a second UE through a physical sidelink control channel (PSCCH). For example, the instructions, when executed, may cause a first device to: receive the second SCI related to a groupcast and medium access control (MAC) protocol data unit (PDU) from the second UE through the PSSCH. For example, the instructions, when executed, may cause a first device to: determine a physical sidelink feedback channel (PSFCH) resource based on an index of a sub-channel related to the PSSCH and an index of a slot. For example, the instructions, when executed, may cause a first device to: based on the second SCI being related to the groupcast, and information representing whether SL hybrid automatic repeat request (HARQ) feedback is enabled included in the second SCI being configured to be enabled, start the SL DRX timer after the PSFCH resource. 
       FIG.  17    shows a method for a second device to perform wireless communication according to 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 an SL DRX configuration including information related to a sidelink (SL) discontinuous reception (DRX) timer. In step S 1720 , the second device may transmit a first SCI for scheduling of second sidelink control information (SCI) and a physical sidelink shared channel (PSSCH) to a first device through a physical sidelink control channel (PSCCH). In step S 1730 , the second device may transmit the second SCI related to a groupcast and medium access control (MAC) protocol data unit (PDU) to the first device through the PSSCH. In step S 1740 , the second device may, based on the second SCI being related to the groupcast, and information representing whether SL hybrid automatic repeat request (HARQ) feedback is enabled included in the second SCI being configured to be enabled, start the SL DRX timer after the PSFCH resource. 
     Additionally or alternatively, the second SCI may include cast type information representing a NACK-only groupcast cast type. 
     Additionally or alternatively, the second SCI may be an SCI to support NACK (negative acknowledge)-only feedback, but not to support positive-negative acknowledgment (ACK) feedback. 
     Additionally or alternatively, the second SCI may further include information regarding a zone ID. 
     Additionally or alternatively, the second SCI may further include information regarding a communication range requirement. 
     Additionally or alternatively, the SL HARQ feedback may include negative acknowledge (NACK) information 
     Additionally or alternatively, the SL HARQ feedback may not include positive acknowledge (ACK) information. 
     Additionally or alternatively, the SL DRX timer may include a SL DRX HARQ roundtrip time (RTT) timer. 
     Additionally or alternatively, based on the information representing whether the SL HARQ feedback is enabled, included in the second SCI related with the groupcast, being configured to HARQ feedback enabled, and the MAC PDU being successfully decoded, the SL DRX timer may be started after the PSFCH resource. 
     Additionally or alternatively, based on the information representing whether the SL HARQ feedback is enabled, included in the second SCI related with the groupcast, being configured to HARQ feedback enabled, the MAC PDU being successfully decoded, and the SL HARQ feedback being not transmitted to the second device on the PSFCH resource, the SL DRX timer may be started after the PSFCH resource. 
     Additionally or alternatively, based on the information representing whether the SL HARQ feedback is enabled being configured to HARQ feedback enabled, and the MAC PDU being successfully decoded, the SL DRX timer may be started after the PSFCH resource. 
     Additionally or alternatively, based on the information representing whether the SL HARQ feedback is enabled being configured to HARQ feedback enabled, the MAC PDU being successfully decoded, and the SL HARQ feedback being not transmitted to the second device on the PSFCH resource, the SL DRX timer may be started after the PSFCH resource. 
     Additionally or alternatively, wherein based on the information representing whether the SL HARQ feedback is enabled being configured to HARQ feedback enabled, the MAC PDU being successfully decoded, and the SL HARQ feedback to the second device being skipped on the PSFCH resource, the SL DRX timer may be started after the PSFCH resource. 
     Additionally or alternatively, the SL HARQ feedback may be positive-ACK information. 
     Additionally or alternatively, the PSFCH resource may be a resource for which the SL HARQ feedback is transmitted. 
     Additionally or alternatively, the SL DRX timer may be started after an end of a time domain of the PSFCH resource. 
     Additionally or alternatively, the SL DRX timer may be started in a first slot after the end of the time domain of the PSFCH resource. 
     Additionally or alternatively, based on the information representing whether the SL HARQ feedback is enabled being configured to HARQ feedback enabled, and the MAC PDU not being successfully decoded, the SL DRX timer may be started after the PSFCH resource. 
     Additionally or alternatively, based on the information representing whether the SL HARQ feedback is enabled being configured to HARQ feedback enabled, the MAC PDU not being successfully decoded, and the SL HARQ feedback being transmitted to the second device on the PSFCH resource, the SL DRX timer may be started after the PSFCH resource. 
     The proposed method may be applied to a device according to various embodiments of the present disclosure. First, a processor  202  of a second device  200  may obtain an SL DRX configuration including information related to a sidelink (SL) discontinuous reception (DRX) timer. a processor  202  of a second device  200  may control a transceiver  206  to a first SCI for scheduling of second sidelink control information (SCI) and a physical sidelink shared channel (PSSCH) to a first device through a physical sidelink control channel (PSCCH). a processor  202  of a second device  200  may control a transceiver  206  to the second SCI related to a groupcast and medium access control (MAC) protocol data unit (PDU) to the first device through the PSSCH. a processor  202  of a second device  200  may, based on the second SCI being related to the groupcast, and information representing whether SL hybrid automatic repeat request (HARQ) feedback is enabled included in the second SCI being configured to be enabled, start the SL DRX timer after the PSFCH resource. 
     According to an embodiment of the present disclosure, a second device for performing wireless communication may be proposed. For example, the second device may include one or more memories storing instructions; one or more transceivers; and one or more processors operably connected to the one or more memories and the one or more transceivers, and the one or more processors may execute the instructions to: obtain an SL DRX configuration including information related to a sidelink (SL) discontinuous reception (DRX) timer. For example, the one or more processors may execute the instructions to: transmit a first SCI for scheduling of second sidelink control information (SCI) and a physical sidelink shared channel (PSSCH) to a first device through a physical sidelink control channel (PSCCH). For example, the one or more processors may execute the instructions to: transmit the second SCI related to a groupcast and medium access control (MAC) protocol data unit (PDU) to the first device through the PSSCH. For example, the one or more processors may execute the instructions to: based on the second SCI being related to the groupcast, and information representing whether SL hybrid automatic repeat request (HARQ) feedback is enabled included in the second SCI being configured to be enabled, start the SL DRX timer after the PSFCH resource. 
     According to an embodiment of the present disclosure, an apparatus configured to control a second UE may be proposed. 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, and the one or more processors may execute the instructions to: obtain an SL DRX configuration including information related to a sidelink (SL) discontinuous reception (DRX) timer. For example, the one or more processors may execute the instructions to: transmit a first SCI for scheduling of second sidelink control information (SCI) and a physical sidelink shared channel (PSSCH) to a first UE through a physical sidelink control channel (PSCCH). For example, the one or more processors may execute the instructions to: transmit the second SCI related to a groupcast and medium access control (MAC) protocol data unit (PDU) to the first UE through the PSSCH. For example, the one or more processors may execute the instructions to: based on the second SCI being related to the groupcast, and information representing whether SL hybrid automatic repeat request (HARQ) feedback is enabled included in the second SCI being configured to be enabled, start the SL DRX timer after the PSFCH resource. 
     According to an embodiment of the present disclosure, a non-transitory computer-readable storage medium storing instructions may be proposed. For example, the instructions, when executed, may cause a second device to: obtain an SL DRX configuration including information related to a sidelink (SL) discontinuous reception (DRX) timer. For example, the instructions, when executed, may cause a second device to: transmit a first SCI for scheduling of second sidelink control information (SCI) and a physical sidelink shared channel (PSSCH) to a first device through a physical sidelink control channel (PSCCH). For example, the instructions, when executed, may cause a second device to: transmit the second SCI related to a groupcast and medium. access control (MAC) protocol data unit (PDU) to the first device through the PSSCH. For example, the instructions, when executed, may cause a second device to: based on the second SCI being related to the groupcast, and information representing whether SL hybrid automatic repeat request (HARQ) feedback is enabled included in the second SCI being configured to be enabled, start, by the second device, the SL DRX timer after the PSFCH resource. 
     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.