Patent Publication Number: US-2022232660-A1

Title: Method of operating a ue related to sidelink drx in a wireless communication system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Pursuant to 35 U.S.C. § 119(a), this application claims the benefit of earlier filing date and right of priority to Korean Application No. 10-2020-0016198, filed on Feb. 11, 2020, the contents of which are hereby incorporated by reference herein in their entirety. 
     TECHNICAL FIELD 
     The following description relates to a wireless communication system, and more particularly, to a method and apparatus for operating a UE related to sidelink Discontinuous Reception (DRX). 
     BACKGROUND 
     A wireless communication system uses various radio access technologies (RATs) such as long term evolution (LTE), LTE-advanced (LTE-A), and wireless fidelity (WiFi). 5th generation (5G) is such a wireless communication system. Three key requirement areas of 5G include (1) enhanced mobile broadband (eMBB), (2) massive machine type communication (mMTC), and (3) ultra-reliable and low latency communications (URLLC). Some use cases may require multiple dimensions for optimization, while others may focus only on one key performance indicator (KPI). 5G supports such diverse use cases in a flexible and reliable way. 
     eMBB goes far beyond basic mobile Internet access and covers rich interactive work, media and entertainment applications in the cloud or augmented reality (AR). Data is one of the key drivers for 5G and in the 5G era, we may for the first time see no dedicated voice service. In 5G, voice is expected to be handled as an application program, simply using data connectivity provided by a communication system. The main drivers for an increased traffic volume are the increase in the size of content and the number of applications requiring high data rates. Streaming services (audio and video), interactive video, and mobile Internet connectivity will continue to be used more broadly as more devices connect to the Internet. Many of these applications require always-on connectivity to push real time information and notifications to users. Cloud storage and applications are rapidly increasing for mobile communication platforms. This is applicable for both work and entertainment. Cloud storage is one particular use case driving the growth of uplink data rates. 5G will also be used for remote work in the cloud which, when done with tactile interfaces, requires much lower end-to-end latencies in order to maintain a good user experience. Entertainment, for example, cloud gaming and video streaming, is another key driver for the increasing need for mobile broadband capacity. Entertainment will be very essential on smart phones and tablets everywhere, including high mobility environments such as trains, cars and airplanes. Another use case is augmented reality (AR) for entertainment and information search, which requires very low latencies and significant instant data volumes. 
     One of the most expected 5G use cases is the functionality of actively connecting embedded sensors in every field, that is, mMTC. It is expected that there will be 20.4 billion potential Internet of things (IoT) devices by 2020. In industrial IoT, 5G is one of areas that play key roles in enabling smart city, asset tracking, smart utility, agriculture, and security infrastructure. 
     URLLC includes services which will transform industries with ultra-reliable/available, low latency links such as remote control of critical infrastructure and self-driving vehicles. The level of reliability and latency are vital to smart-grid control, industrial automation, robotics, drone control and coordination, and so on. 
     Now, multiple use cases will be described in detail. 
     5G may complement fiber-to-the home (FTTH) and cable-based broadband (or data-over-cable service interface specifications (DOCSIS)) as a means of providing streams at data rates of hundreds of megabits per second to giga bits per second. Such a high speed is required for TV broadcasts at or above a resolution of 4K (6K, 8K, and higher) as well as virtual reality (VR) and AR. VR and AR applications mostly include immersive sport games. A special network configuration may be required for a specific application program. For VR games, for example, game companies may have to integrate a core server with an edge network server of a network operator in order to minimize latency. 
     The automotive sector is expected to be a very important new driver for 5G, with many use cases for mobile communications for vehicles. For example, entertainment for passengers requires simultaneous high capacity and high mobility mobile broadband, because future users will expect to continue their good quality connection independent of their location and speed. Other use cases for the automotive sector are AR dashboards. These display overlay information on top of what a driver is seeing through the front window, identifying objects in the dark and telling the driver about the distances and movements of the objects. In the future, wireless modules will enable communication between vehicles themselves, information exchange between vehicles and supporting infrastructure and between vehicles and other connected devices (e.g., those carried by pedestrians). Safety systems may guide drivers on alternative courses of action to allow them to drive more safely and lower the risks of accidents. The next stage will be remote-controlled or self-driving vehicles. These require very reliable, very fast communication between different self-driving vehicles and between vehicles and infrastructure. In the future, self-driving vehicles will execute all driving activities, while drivers are focusing on traffic abnormality elusive to the vehicles themselves. The technical requirements for self-driving vehicles call for ultra-low latencies and ultra-high reliability, increasing traffic safety to levels humans cannot achieve. 
     Smart cities and smart homes, often referred to as smart society, will be embedded with dense wireless sensor networks. Distributed networks of intelligent sensors will identify conditions for cost- and energy-efficient maintenance of the city or home. A similar setup can be done for each home, where temperature sensors, window and heating controllers, burglar alarms, and home appliances are all connected wirelessly. Many of these sensors are typically characterized by low data rate, low power, and low cost, but for example, real time high definition (HD) video may be required in some types of devices for surveillance. 
     The consumption and distribution of energy, including heat or gas, is becoming highly decentralized, creating the need for automated control of a very distributed sensor network. A smart grid interconnects such sensors, using digital information and communications technology to gather and act on information. This information may include information about the behaviors of suppliers and consumers, allowing the smart grid to improve the efficiency, reliability, economics and sustainability of the production and distribution of fuels such as electricity in an automated fashion. A smart grid may be seen as another sensor network with low delays. 
     The health sector has many applications that may benefit from mobile communications. Communications systems enable telemedicine, which provides clinical health care at a distance. It helps eliminate distance barriers and may improve access to medical services that would often not be consistently available in distant rural communities. It is also used to save lives in critical care and emergency situations. Wireless sensor networks based on mobile communication may provide remote monitoring and sensors for parameters such as heart rate and blood pressure. 
     Wireless and mobile communications are becoming increasingly important for industrial applications. Wires are expensive to install and maintain, and the possibility of replacing cables with reconfigurable wireless links is a tempting opportunity for many industries. However, achieving this requires that the wireless connection works with a similar delay, reliability and capacity as cables and that its management is simplified. Low delays and very low error probabilities are new requirements that need to be addressed with 5G. 
     Finally, logistics and freight tracking are important use cases for mobile communications that enable the tracking of inventory and packages wherever they are by using location-based information systems. The logistics and freight tracking use cases typically require lower data rates but need wide coverage and reliable location information. 
     A wireless communication system is a multiple access system that supports communication of multiple users by sharing available system resources (a bandwidth, transmission power, etc.). Examples of multiple access systems include a CDMA system, an FDMA system, a TDMA system, an OFDMA system, an SC-FDMA system, and an MC-FDMA system. 
     Sidelink (SL) refers to a communication scheme in which a direct link is established between user equipments (UEs) and the UEs directly exchange voice or data without intervention of a base station (BS). SL is considered as a solution of relieving the BS of the constraint of rapidly growing data traffic. 
     Vehicle-to-everything (V2X) is a communication technology in which a vehicle exchanges information with another vehicle, a pedestrian, and infrastructure by wired/wireless communication. V2X may be categorized into four types: vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), vehicle-to-network (V2N), and vehicle-to-pedestrian (V2P). V2X communication may be provided via a PC5 interface and/or a Uu interface. 
     As more and more communication devices demand larger communication capacities, there is a need for enhanced mobile broadband communication relative to existing RATs. Accordingly, a communication system is under discussion, for which services or UEs sensitive to reliability and latency are considered. The next-generation RAT in which eMBB, MTC, and URLLC are considered is referred to as new RAT or NR. In NR, V2X communication may also be supported. 
       FIG. 1  is a diagram illustrating V2X communication based on pre-NR RAT and V2X communication based on NR in comparison. 
     For V2X communication, a technique of providing safety service based on V2X messages such as basic safety message (BSM), cooperative awareness message (CAM), and decentralized environmental notification message (DENM) was mainly discussed in the pre-NR RAT. The V2X message may include location information, dynamic information, and attribute information. For example, a UE may transmit a CAM of a periodic message type and/or a DENM of an event-triggered type to another UE. 
     For example, the CAM may include basic vehicle information including dynamic state information such as a direction and a speed, vehicle static data such as dimensions, an external lighting state, path details, and so on. For example, the UE may broadcast the CAM which may have a latency less than 100 ms. For example, when an unexpected incident occurs, such as breakage or an accident of a vehicle, the UE may generate the DENM and transmit the DENM to another UE. For example, all vehicles within the transmission range of the UE may receive the CAM and/or the DENM. In this case, the DENM may have priority over the CAM. 
     In relation to V2X communication, various V2X scenarios are presented in NR. For example, the V2X scenarios include vehicle platooning, advanced driving, extended sensors, and remote driving. 
     For example, vehicles may be dynamically grouped and travel together based on vehicle platooning. For example, to perform platoon operations based on vehicle platooning, the vehicles of the group may receive periodic data from a leading vehicle. For example, the vehicles of the group may widen or narrow their gaps based on the periodic data. 
     For example, a vehicle may be semi-automated or full-automated based on advanced driving. For example, each vehicle may adjust a trajectory or maneuvering based on data obtained from a nearby vehicle and/or a nearby logical entity. For example, each vehicle may also share a dividing intention with nearby vehicles. 
     Based on extended sensors, for example, raw or processed data obtained through local sensor or live video data may be exchanged between vehicles, logical entities, terminals of pedestrians and/or V2X application servers. Accordingly, a vehicle may perceive an advanced environment relative to an environment perceivable by its sensor. 
     Based on remote driving, for example, a remote driver or a V2X application may operate or control a remote vehicle on behalf of a person incapable of driving or in a dangerous environment. For example, when a path may be predicted as in public transportation, cloud computing-based driving may be used in operating or controlling the remote vehicle. For example, access to a cloud-based back-end service platform may also be used for remote driving. 
     A scheme of specifying service requirements for various V2X scenarios including vehicle platooning, advanced driving, extended sensors, and remote driving is under discussion in NR-based V2X communication. 
     SUMMARY 
     Accordingly, embodiments of the present disclosure are directed to a method and apparatus for operating a UE related to sidelink Discontinuous Reception (DRX) that substantially obviate one or more problems due to limitations and disadvantages of the related art. 
     One object of the present disclosure is to provide methods of configuring a sidelink DRX by a specific subject in a sidelink operation based on alignment of Uu DRX configuration and sidelink DRX configuration. 
     Technical tasks obtainable from the present disclosure are non-limited by the above-mentioned technical tasks. And, other unmentioned technical tasks can be clearly understood from the following description by those having ordinary skill in the technical field to which the present disclosure pertains. 
     Additional advantages, objects, and features of the disclosure will be set forth in the disclosure herein as well as the accompanying drawings. Such aspects may also be appreciated by those skilled in the art based on the disclosure herein. 
     To achieve these objects and other advantages and in accordance with the purpose of the disclosure, as embodied and broadly described herein, a method of performing a sidelink Discontinuous Reception (DRX) related operation by a User Equipment (UE) 2 in a wireless communication system according to one embodiment of the present disclosure may include receiving by the UE 2 a sidelink DRX configuration from a UE 1 and performing by the UE 2 a DRX related operation based on the sidelink DRX configuration, wherein the sidelink DRX configuration may be determined based on a Uu DRX configuration. 
     In another aspect of the present disclosure, as embodied and broadly described herein, a User Equipment (UE) 2 related to a sidelink Discontinuous Reception (DRX) in a wireless communication system according to one embodiment of the present disclosure may include at least one processor and at least one computer memory configured to be operatively connected to the at least one processor and store commands for enabling the at least one processor to perform operations, wherein the operations may include receiving by the UE 2 a sidelink DRX configuration from a UE 1 and performing by the UE 2 a DRX related operation based on the sidelink DRX configuration and wherein the sidelink DRX configuration may be determined based on a Uu DRX configuration. 
     In another aspect of the present disclosure, as embodied and broadly described herein, a processor according to one embodiment of the present disclosure may perform operations for a User Equipment (UE) 2 in a wireless communication system, wherein the operations may include receiving by the UE 2 a sidelink DRX configuration from a UE 1 and performing by the UE 2 a DRX related operation based on the sidelink DRX configuration and wherein the sidelink DRX configuration may be determined based on a Uu DRX configuration. 
     In further aspect of the present disclosure, as embodied and broadly described herein, a non-volatile computer-readable storage medium according to one embodiment of the present disclosure may store at least one computer program including commands for enabling at least one processor to perform operations for a User Equipment (UE) 2 when executed by the at least one processor, wherein the operations may include receiving by the UE 2 a sidelink DRX configuration from a UE 1 and performing by the UE 2 a DRX related operation based on the sidelink DRX configuration and wherein the sidelink DRX configuration may be determined based on a Uu DRX configuration. 
     The sidelink DRX configuration may be determined by either a base station or the UE 1 based on that the UE 2 is in connected state. 
     The sidelink DRX configuration may be determined by the UE 1 based on that the UE 2 is not in connected state. 
     At least one of the Uu DRX configuration or the sidelink DRX configuration may be determined based on assist information. 
     The assist information may be transmitted to the UE 1 by the UE 2. 
     The assist information may be forwarded to a base station via the UE 1. 
     The assist information may include at least one of QoS of a data/control signal, latency requirement, UE speed, UE location, sidelink measurement, or remaining battery capacity. 
     ‘On duration’ of the sidelink DRX configuration may be a subset of ‘on duration’ of the Uu DRX configuration. 
     ‘On duration’ of the sidelink DRX configuration may overlap with ‘on duration’ of the Uu DRX configuration at least in part. 
     The UE 2 may report a sidelink DRX configuration of a peer UE to the base station. 
     A service-specific DRX configuration may be forwarded to the base station from a Core Network (CN). 
     The UE 2 may communicate with at least one of another user equipment, a UE related to an autonomous driving vehicle, a base station, or a network. 
     Accordingly, embodiments of the present disclosure provide various effects and/or features. 
     According to one embodiment, Uu DRX configuration and sidelink DRX configuration are effectively aligned, thereby increasing a power saving effect. 
     Effects obtainable from the present disclosure may be non-limited by the above mentioned effect. And, other unmentioned effects can be clearly understood from the following description by those having ordinary skill in the technical field to which the present disclosure pertains. 
     It is to be understood that both the foregoing general description and the following detailed description of the present disclosure are exemplary and explanatory and are intended to provide further explanation of the disclosure as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this application, illustrate embodiments of the disclosure and together with the description serve to explain the principle of the disclosure. In the drawings: 
         FIG. 1  is a diagram comparing vehicle-to-everything (V2X) communication based on pre-new radio access technology (pre-NR) with V2X communication based on NR; 
         FIG. 2  is a diagram illustrating the structure of a long term evolution (LTE) system according to an embodiment of the present disclosure; 
         FIGS. 3A and 3B  are diagrams illustrating user-plane and control-plane radio protocol architectures according to an embodiment of the present disclosure; 
         FIG. 4  is a diagram illustrating the structure of an NR system according to an embodiment of the present disclosure; 
         FIG. 5  is a diagram illustrating functional split between a next generation radio access network (NG-RAN) and a 5 th  generation core network (5GC) according to an embodiment of the present disclosure; 
         FIG. 6  is a diagram illustrating the structure of an NR radio frame according to an embodiment of the present disclosure; 
         FIG. 7  is a diagram illustrating a slot structure of an NR frame according to an embodiment of the present disclosure; 
         FIGS. 8A and 8B  are diagrams illustrating radio protocol architectures for sidelink (SL) communication according to an embodiment of the present disclosure; 
         FIGS. 9A and 9B  are diagrams illustrating radio protocol architectures for SL communication according to an embodiment of the present disclosure; 
         FIGS. 10A and 10B  illustrate a procedure for a UE to perform V2X or SL communication depending on a transmission mode according to one embodiment of the present disclosure; 
         FIG. 11  and  FIG. 12  are diagrams to describe DRX; 
         FIGS. 13 to 16  are diagrams to describe various embodiment(s) related to configuration of DRX; and 
         FIGS. 17 to 23  are diagrams to describe various devices to which embodiment(s) are applicable. 
     
    
    
     DETAILED DESCRIPTION 
     In various embodiments of the present disclosure, “I” and “,” should be interpreted as “and/or”. For example, “A/B” may mean “A and/or B”. Further, “A, B” may mean “A and/or B”. Further, “AB/C” may mean “at least one of A, B and/or C”. Further, “A, B, C” may mean “at least one of A, B and/or C”. 
     In various embodiments of the present disclosure, “or” should be interpreted as “and/or”. For example, “A or B” may include “only A”, “only B”, and/or “both A and B”. In other words, “or” should be interpreted as “additionally or alternatively”. 
     Techniques described herein may be used in various wireless access 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. CDMA may be implemented as a radio technology such as universal terrestrial radio access (UTRA) or CDMA2000. TDMA may be implemented as a radio technology such as global system for mobile communications (GSM)/general packet radio service (GPRS)/Enhanced Data Rates for GSM Evolution (EDGE). OFDMA may be implemented as a radio technology such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, evolved-UTRA (E-UTRA), or the like. IEEE 802.16m is an evolution of IEEE 802.16e, offering backward compatibility with an IRRR 802.16e-based system. UTRA is a part of universal mobile telecommunications system (UMTS). 3 rd  generation partnership project (3GPP) long term evolution (LTE) is a part of evolved UMTS (E-UMTS) using evolved UTRA (E-UTRA). 3GPP LTE employs OFDMA for downlink (DL) and SC-FDMA for uplink (UL). LTE-advanced (LTE-A) is an evolution of 3GPP LTE. 
     A successor to LTE-A, 5 th  generation (5G) new radio access technology (NR) is a new clean-state mobile communication system characterized by high performance, low latency, and high availability. 5G NR may use all available spectral resources including a low frequency band below 1 GHz, an intermediate frequency band between 1 GHz and 10 GHz, and a high frequency (millimeter) band of 24 GHz or above. 
     While the following description is given mainly in the context of LTE-A or 5G NR for the clarity of description, the technical idea of an embodiment of the present disclosure is not limited thereto. 
       FIG. 2  illustrates the structure of an LTE system according to an embodiment of the present disclosure. This may also be called an evolved UMTS terrestrial radio access network (E-UTRAN) or LTE/LTE-A system. 
     Referring to  FIG. 2 , the E-UTRAN includes evolved Node Bs (eNBs)  20  which provide a control plane and a user plane to UEs  10 . A UE  10  may be fixed or mobile, and may also be referred to as a mobile station (MS), user terminal (UT), subscriber station (SS), mobile terminal (MT), or wireless device. An eNB  20  is a fixed station communication with the UE  10  and may also be referred to as a base station (BS), a base transceiver system (BTS), or an access point. 
     eNBs  20  may be connected to each other via an X2 interface. An eNB  20  is connected to an evolved packet core (EPC)  39  via an S1 interface. More specifically, the eNB  20  is connected to a mobility management entity (MME) via an S1-MME interface and to a serving gateway (S-GW) via an S1-U interface. 
     The EPC  30  includes an MME, an S-GW, and a packet data network-gateway (P-GW). The MME has access information or capability information about UEs, which are mainly used for mobility management of the UEs. The S-GW is a gateway having the E-UTRAN as an end point, and the P-GW is a gateway having a packet data network (PDN) as an end point. 
     Based on the lowest three layers of the open system interconnection (OSI) reference model known in communication systems, the radio protocol stack between a UE and a network may be divided into Layer 1 (L1), Layer 2 (L2) and Layer 3 (L3). These layers are defined in pairs between a UE and an Evolved UTRAN (E-UTRAN), for data transmission via the Uu interface. The physical (PHY) layer at L1 provides an information transfer service on physical channels. The radio resource control (RRC) layer at L3 functions to control radio resources between the UE and the network. For this purpose, the RRC layer exchanges RRC messages between the UE and an eNB. 
       FIG. 3A  illustrates a user-plane radio protocol architecture according to an embodiment of the disclosure. 
       FIG. 3B  illustrates a control-plane radio protocol architecture according to an embodiment of the disclosure. A user plane is a protocol stack for user data transmission, and a control plane is a protocol stack for control signal transmission. 
     Referring to  FIGS. 3A and 3B , the PHY layer provides an information transfer service to its higher layer on physical channels. The PHY layer is connected to the medium access control (MAC) layer through transport channels and data is transferred between the MAC layer and the PHY layer on the transport channels. The transport channels are divided according to features with which data is transmitted via a radio interface. 
     Data is transmitted on physical channels between different PHY layers, that is, the PHY layers of a transmitter and a receiver. The physical channels may be modulated in orthogonal frequency division multiplexing (OFDM) and use time and frequencies as radio resources. 
     The MAC layer provides services to a higher layer, radio link control (RLC) on logical channels. The MAC layer provides a function of mapping from a plurality of logical channels to a plurality of transport channels. Further, the MAC layer provides a logical channel multiplexing function by mapping a plurality of logical channels to a single transport channel. A MAC sublayer provides a data transmission service on the logical channels. 
     The RLC layer performs concatenation, segmentation, and reassembly for RLC serving data units (SDUs). In order to guarantee various quality of service (QoS) requirements of each radio bearer (RB), the RLC layer provides three operation modes, transparent mode (TM), unacknowledged mode (UM), and acknowledged Mode (AM). An AM RLC provides error correction through automatic repeat request (ARQ). 
     The RRC layer is defined only in the control plane and controls logical channels, transport channels, and physical channels in relation to configuration, reconfiguration, and release of RBs. An RB refers to a logical path provided by L1 (the PHY layer) and L2 (the MAC layer, the RLC layer, and the packet data convergence protocol (PDCP) layer), for data transmission between the UE and the network. 
     The user-plane functions of the PDCP layer include user data transmission, header compression, and ciphering. The control-plane functions of the PDCP layer include control-plane data transmission and ciphering/integrity protection. 
     RB establishment amounts to a process of defining radio protocol layers and channel features and configuring specific parameters and operation methods in order to provide a specific service. RBs may be classified into two types, signaling radio bearer (SRB) and data radio bearer (DRB). The SRB is used as a path in which an RRC message is transmitted on the control plane, whereas the DRB is used as a path in which user data is transmitted on the user plane. 
     Once an RRC connection is established between the RRC layer of the UE and the RRC layer of the E-UTRAN, the UE is placed in RRC_CONNECTED state, and otherwise, the UE is placed in RRC_IDLE state. In NR, RRC_INACTIVE state is additionally defined. A UE in the RRC_INACTIVE state may maintain a connection to a core network, while releasing a connection from an eNB. 
     DL transport channels carrying data from the network to the UE include a broadcast channel (BCH) on which system information is transmitted and a DL shared channel (DL SCH) on which user traffic or a control message is transmitted. Traffic or a control message of a DL multicast or broadcast service may be transmitted on the DL-SCH or a DL multicast channel (DL MCH). UL transport channels carrying data from the UE to the network include a random access channel (RACH) on which an initial control message is transmitted and an UL shared channel (UL SCH) on which user traffic or a control message is transmitted. 
     The logical channels which are above and mapped to the transport channels include a broadcast control channel (BCCH), a paging control channel (PCCH), a common control channel (CCCH), a multicast control channel (MCCH), and a multicast traffic channel (MTCH). 
     A physical channel includes a plurality of OFDM symbol in the time domain by a plurality of subcarriers in the frequency domain. One subframe includes a plurality of OFDM symbols in the time domain. An RB is a resource allocation unit defined by a plurality of OFDM symbols by a plurality of subcarriers. Further, each subframe may use specific subcarriers of specific OFDM symbols (e.g., the first OFDM symbol) in a corresponding subframe for a physical DL control channel (PDCCH), that is, an L1/L2 control channel. A transmission time interval (TTI) is a unit time for subframe transmission. 
       FIG. 4  illustrates the structure of an NR system according to an embodiment of the present disclosure. 
     Referring to  FIG. 4 , a next generation radio access network (NG-RAN) may include a next generation Node B (gNB) and/or an eNB, which provides user-plane and control-plane protocol termination to a UE. In  FIG. 4 , the NG-RAN is shown as including only gNBs, by way of example. A gNB and an eNB are connected to each other via an Xn interface. The gNB and the eNB are connected to a 5G core network (5GC) via an NG interface. More specifically, the gNB and the eNB are connected to an access and mobility management function (AMF) via an NG-C interface and to a user plane function (UPF) via an NG-U interface. 
       FIG. 5  illustrates functional split between the NG-RAN and the 5GC according to an embodiment of the present disclosure. 
     Referring to  FIG. 5 , a gNB may provide functions including inter-cell radio resource management (RRM), radio admission control, measurement configuration and provision, and dynamic resource allocation. The AMF may provide functions such as non-access stratum (NAS) security and idle-state mobility processing. The UPF may provide functions including mobility anchoring and protocol data unit (PDU) processing. A session management function (SMF) may provide functions including UE Internet protocol (IP) address allocation and PDU session control. 
       FIG. 6  illustrates a radio frame structure in NR, to which embodiment(s) of the present disclosure is applicable. 
     Referring to  FIG. 6 , a radio frame may be used for UL transmission and DL transmission in NR. A radio frame is 10 ms in length, and may be defined by two 5-ms half-frames. An HF may include five 1-ms subframes. A subframe may be divided into one or more slots, and the number of slots in an SF may be determined according to a subcarrier spacing (SCS). Each slot may include 12 or 14 OFDM(A) symbols according to a cyclic prefix (CP). 
     In a normal CP (NCP) case, each slot may include 14 symbols, whereas in an extended CP (ECP) case, each slot may include 12 symbols. Herein, a symbol may be an OFDM symbol (or CP-OFDM symbol) or an SC-FDMA symbol (or DFT-s-OFDM symbol). 
     [Table 1] below lists the number of symbols per slot N slot   symb , the number of slots per frame N frame,u   slot , and the number of slots per subframe N subframe,u   slot  according to an SCS configuration μ in the NCP case. 
     
       
         
           
               
               
               
               
               
             
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 SCS (15*2u) 
                 N slot   symb   
                 N frame, u   slot   
                 N subframe, u   slot   
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
            
               
                   
                  15 KHz (u = 0) 
                 14 
                 10 
                 1 
               
               
                   
                  30 KHz (u = 1) 
                 14 
                 20 
                 2 
               
               
                   
                  60 KHz (u = 2) 
                 14 
                 40 
                 4 
               
               
                   
                 120 KHz (u = 3) 
                 14 
                 80 
                 8 
               
               
                   
                 240 KHz (u = 4) 
                 14 
                 160 
                 16 
               
               
                   
                   
               
            
           
         
       
     
     [Table 2] below lists the number of symbols per slot, the number of slots per frame, and the number of slots per subframe according to an SCS in the ECP case. 
     
       
         
           
               
               
               
               
               
             
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                 SCS (15*2{circumflex over ( )}u) 
                 N slot   symb   
                 N frame, u   slot   
                 N subframe, u   slot   
               
               
                   
                   
               
             
            
               
                   
                 60 KHz (u = 2) 
                 12 
                 40 
                 4 
               
               
                   
                   
               
            
           
         
       
     
     In the NR system, different OFDM(A) numerologies (e.g., SCSs, CP lengths, and so on) may be configured for a plurality of cells aggregated for one UE. Accordingly, the (absolute time) duration of a time resource including the same number of symbols (e.g., a subframe, slot, or TTI) (collectively referred to as a time unit (TU) for convenience) may be configured to be different for the aggregated cells. 
     In NR, various numerologies or SCSs may be supported to support various 5G services. For example, with an SCS of 15 kHz, a wide area in traditional cellular bands may be supported, while with an SCS of 30 kHz/60 kHz, a dense urban area, a lower latency, and a wide carrier bandwidth may be supported. With an SCS of 60 kHz or higher, a bandwidth larger than 24.25 GHz may be supported to overcome phase noise. 
     An NR frequency band may be defined by two types of frequency ranges, FR1 and FR2. The numerals in each frequency range may be changed. For example, the two types of frequency ranges may be given in [Table 3]. In the NR system, FR1 may be a “sub 6 GHz range” and FR2 may be an “above 6 GHz range” called millimeter wave (mmW). 
     
       
         
           
               
               
               
               
             
               
                   
                 TABLE 3 
               
               
                   
                   
               
               
                   
                 Frequency Range 
                 Corresponding  
                 Subcarrier  
               
               
                   
                 designation 
                 frequency range 
                 Spacing (SCS) 
               
               
                   
                   
               
             
            
               
                   
                 FR1 
                  450 MHz-6000 MHz 
                 15, 30, 60 kHz 
               
               
                   
                 FR2 
                 24250 MHz-52600 MHz 
                 60, 120, 240 kHz 
               
               
                   
                   
               
            
           
         
       
     
     As mentioned above, the numerals in a frequency range may be changed in the NR system. For example, FR1 may range from 410 MHz to 7125 MHz as listed in [Table 4]. That is, FR1 may include a frequency band of 6 GHz (or 5850, 5900, and 5925 MHz) or above. For example, the frequency band of 6 GHz (or 5850, 5900, and 5925 MHz) or above may include an unlicensed band. The unlicensed band may be used for various purposes, for example, vehicle communication (e.g., autonomous driving). 
     
       
         
           
               
               
               
               
             
               
                   
                 TABLE 4 
               
               
                   
                   
               
               
                   
                 Frequency Range 
                 Corresponding  
                 Subcarrier  
               
               
                   
                 designation 
                 frequency range 
                 Spacing (SCS) 
               
               
                   
                   
               
             
            
               
                   
                 FR1 
                  410 MHz-7125 MHz 
                 15, 30, 60 kHz 
               
               
                   
                 FR2 
                 24250 MHz-52600 MHz 
                 60, 120, 240 kHz 
               
               
                   
                   
               
            
           
         
       
     
       FIG. 7  illustrates a slot structure in an NR frame according to an embodiment of the present disclosure. 
     Referring to  FIG. 7 , a slot includes a plurality of symbols in the time domain. For example, one slot may include 14 symbols in an NCP case and 12 symbols in an ECP case. Alternatively, one slot may include 7 symbols in an NCP case and 6 symbols in an ECP case. 
     A carrier includes a plurality of subcarriers in the frequency domain. An RB may be defined by a plurality of (e.g., 12) consecutive subcarriers in the frequency domain. A bandwidth part (BWP) may be defined by a plurality of consecutive (physical) RBs ((P)RBs) in the frequency domain and correspond to one numerology (e.g., SCS, CP length, or the like). A carrier may include up to N (e.g., 5) BWPs. Data communication may be conducted in an activated BWP. Each element may be referred to as a resource element (RE) in a resource grid, to which one complex symbol may be mapped. 
     A radio interface between UEs or a radio interface between a UE and a network may include L1, L2, and L3. In various embodiments of the present disclosure, L1 may refer to the PHY layer. For example, L2 may refer to at least one of the MAC layer, the RLC layer, the PDCH layer, or the SDAP layer. For example, L3 may refer to the RRC layer. 
     Now, a description will be given of sidelink (SL) communication. 
       FIGS. 8A and 8B  illustrate a radio protocol architecture for SL communication according to an embodiment of the present disclosure. Specifically,  FIG. 8A  illustrates a user-plane protocol stack in LTE, and  FIG. 8B  illustrates a control-plane protocol stack in LTE. 
       FIGS. 9A and 9B  illustrate a radio protocol architecture for SL communication according to an embodiment of the present disclosure. Specifically,  FIG. 9A  illustrates a user-plane protocol stack in NR, and  FIG. 9B  illustrates a control-plane protocol stack in NR. 
     Resource allocation in SL will be described below. 
       FIGS. 10A and 10B  illustrate a procedure of performing V2X or SL communication according to a transmission mode in a UE according to an embodiment of the present disclosure. In various embodiments of the present disclosure, a transmission mode may also be referred to as a mode or a resource allocation mode. For the convenience of description, a transmission mode in LTE may be referred to as an LTE transmission mode, and a transmission mode in NR may be referred to as an NR resource allocation mode. 
     For example,  FIG. 10A  illustrates a UE operation related to LTE transmission mode 1 or LTE transmission mode 3. Alternatively, for example,  FIG. 10A  illustrates a UE operation related to NR resource allocation mode 1. For example, LTE transmission mode 1 may be applied to general SL communication, and LTE transmission mode 3 may be applied to V2X communication. 
     For example,  FIG. 10B  illustrates a UE operation related to LTE transmission mode 2 or LTE transmission mode 4. Alternatively, for example,  FIG. 10B  illustrates a UE operation related to NR resource allocation mode 2. 
     Referring to  FIG. 10A , in LTE transmission mode 1, LTE transmission mode 3, or NR resource allocation mode 1, a BS may schedule SL resources to be used for SL transmission of a UE. For example, the BS may perform resource scheduling for UE1 through a PDCCH (more specifically, DL control information (DCI)), and UE1 may perform V2X or SL communication with UE2 according to the resource scheduling. For example, UE1 may transmit sidelink control information (SCI) to UE2 on a PSCCH, and then transmit data based on the SCI to UE2 on a PSSCH. 
     For example, in NR resource allocation mode 1, a UE may be provided with or allocated resources for one or more SL transmissions of one transport block (TB) by a dynamic grant from the BS. For example, the BS may provide the UE with resources for transmission of a PSCCH and/or a PSSCH by the dynamic grant. For example, a transmitting UE may report an SL hybrid automatic repeat request (SL HARQ) feedback received from a receiving UE to the BS. In this case, PUCCH resources and a timing for reporting the SL HARQ feedback to the BS may be determined based on an indication in a PDCCH, by which the BS allocates resources for SL transmission. 
     For example, the DCI may indicate a slot offset between the DCI reception and a first SL transmission scheduled by the DCI. For example, a minimum gap between the DCI that schedules the SL transmission resources and the resources of the first scheduled SL transmission may not be smaller than a processing time of the UE. 
     For example, in NR resource allocation mode 1, the UE may be periodically provided with or allocated a resource set for a plurality of SL transmissions through a configured grant from the BS. For example, the grant to be configured may include configured grant type 1 or configured grant type 2. For example, the UE may determine a TB to be transmitted in each occasion indicated by a given configured grant. 
     For example, the BS may allocate SL resources to the UE in the same carrier or different carriers. 
     For example, an NR gNB may control LTE-based SL communication. For example, the NR gNB may transmit NR DCI to the UE to schedule LTE SL resources. In this case, for example, a new RNTI may be defined to scramble the NR DCI. For example, the UE may include an NR SL module and an LTE SL module. 
     For example, after the UE including the NR SL module and the LTE SL module receives NR SL DCI from the gNB, the NR SL module may convert the NR SL DCI into LTE DCI type 5A, and transmit LTE DCI type 5A to the LTE SL module every Xms. For example, after the LTE SL module receives LTE DCI format 5A from the NR SL module, the LTE SL module may activate and/or release a first LTE subframe after Z ms. For example, X may be dynamically indicated by a field of the DCI. For example, a minimum value of X may be different according to a UE capability. For example, the UE may report a single value according to its UE capability. For example, X may be positive. 
     Referring to  FIG. 10B , in LTE transmission mode 2, LTE transmission mode 4, or NR resource allocation mode 2, the UE may determine SL transmission resources from among SL resources preconfigured or configured by the BS/network. For example, the preconfigured or configured SL resources may be a resource pool. For example, the UE may autonomously select or schedule SL transmission resources. For example, the UE may select resources in a configured resource pool on its own and perform SL communication in the selected resources. For example, the UE may select resources within a selection window on its own by a sensing and resource (re)selection procedure. For example, the sensing may be performed on a subchannel basis. UE1, which has autonomously selected resources in a resource pool, may transmit SCI to UE2 on a PSCCH and then transmit data based on the SCI to UE2 on a PSSCH. 
     For example, a UE may help another UE with SL resource selection. For example, in NR resource allocation mode 2, the UE may be configured with a grant configured for SL transmission. For example, in NR resource allocation mode 2, the UE may schedule SL transmission for another UE. For example, in NR resource allocation mode 2, the UE may reserve SL resources for blind retransmission. 
     For example, in NR resource allocation mode 2, UE1 may indicate the priority of SL transmission to UE2 by SCI. For example, UE2 may decode the SCI and perform sensing and/or resource (re)selection based on the priority. For example, the resource (re)selection procedure may include identifying candidate resources in a resource selection window by UE2 and selecting resources for (re)transmission from among the identified candidate resources by UE2. For example, the resource selection window may be a time interval during which the UE selects resources for SL transmission. For example, after UE2 triggers resource (re)selection, the resource selection window may start at T1≥0, and may be limited by the remaining packet delay budget of UE2. For example, when specific resources are indicated by the SCI received from UE1 by the second UE and an L1 SL reference signal received power (RSRP) measurement of the specific resources exceeds an SL RSRP threshold in the step of identifying candidate resources in the resource selection window by UE2, UE2 may not determine the specific resources as candidate resources. For example, the SL RSRP threshold may be determined based on the priority of SL transmission indicated by the SCI received from UE1 by UE2 and the priority of SL transmission in the resources selected by UE2. 
     For example, the L1 SL RSRP may be measured based on an SL demodulation reference signal (DMRS). For example, one or more PSSCH DMRS patterns may be configured or preconfigured in the time domain for each resource pool. For example, PDSCH DMRS configuration type 1 and/or type 2 may be identical or similar to a PSSCH DMRS pattern in the frequency domain. For example, an accurate DMRS pattern may be indicated by the SCI. For example, in NR resource allocation mode 2, the transmitting UE may select a specific DMRS pattern from among DMRS patterns configured or preconfigured for the resource pool. 
     For example, in NR resource allocation mode 2, the transmitting UE may perform initial transmission of a TB without reservation based on the sensing and resource (re)selection procedure. For example, the transmitting UE may reserve SL resources for initial transmission of a second TB using SCI associated with a first TB based on the sensing and resource (re)selection procedure. 
     For example, in NR resource allocation mode 2, the UE may reserve resources for feedback-based PSSCH retransmission through signaling related to a previous transmission of the same TB. For example, the maximum number of SL resources reserved for one transmission, including a current transmission, may be 2, 3 or 4. For example, the maximum number of SL resources may be the same regardless of whether HARQ feedback is enabled. For example, the maximum number of HARQ (re)transmissions for one TB may be limited by a configuration or preconfiguration. For example, the maximum number of HARQ (re)transmissions may be up to 32. For example, if there is no configuration or preconfiguration, the maximum number of HARQ (re)transmissions may not be specified. For example, the configuration or preconfiguration may be for the transmitting UE. For example, in NR resource allocation mode 2, HARQ feedback for releasing resources which are not used by the UE may be supported. 
     For example, in NR resource allocation mode 2, the UE may indicate one or more subchannels and/or slots used by the UE to another UE by SCI. For example, the UE may indicate one or more subchannels and/or slots reserved for PSSCH (re)transmission by the UE to another UE by SCI. For example, a minimum allocation unit of SL resources may be a slot. For example, the size of a subchannel may be configured or preconfigured for the UE. 
     SCI will be described below. 
     While control information transmitted from a BS to a UE on a PDCCH is referred to as DCI, control information transmitted from one UE to another UE on a PSCCH may be referred to as SCI. For example, the UE may know the starting symbol of the PSCCH and/or the number of symbols in the PSCCH before decoding the PSCCH. For example, the SCI may include SL scheduling information. For example, the UE may transmit at least one SCI to another UE to schedule the PSSCH. For example, one or more SCI formats may be defined. 
     For example, the transmitting UE may transmit the SCI to the receiving UE on the PSCCH. The receiving UE may decode one SCI to receive the PSSCH from the transmitting UE. 
     For example, the transmitting UE may transmit two consecutive SCIs (e.g., 2-stage SCI) on the PSCCH and/or PSSCH to the receiving UE. The receiving UE may decode the two consecutive SCIs (e.g., 2-stage SCI) to receive the PSSCH from the transmitting UE. For example, when SCI configuration fields are divided into two groups in consideration of a (relatively) large SCI payload size, SCI including a first SCI configuration field group is referred to as first SCI. SCI including a second SCI configuration field group may be referred to as second SCI. For example, the transmitting UE may transmit the first SCI to the receiving UE on the PSCCH. For example, the transmitting UE may transmit the second SCI to the receiving UE on the PSCCH and/or PSSCH. For example, the second SCI may be transmitted to the receiving UE on an (independent) PSCCH or on a PSSCH in which the second SCI is piggybacked to data. For example, the two consecutive SCIs may be applied to different transmissions (e.g., unicast, broadcast, or groupcast). 
     For example, the transmitting UE may transmit all or part of the following information to the receiving UE by SCI. For example, the transmitting UE may transmit all or part of the following information to the receiving UE by first SCI and/or second SCI.
         PSSCH-related and/or PSCCH-related resource allocation information, for example, the positions/number of time/frequency resources, resource reservation information (e.g. a periodicity), and/or   an SL channel state information (CSI) report request indicator or SL (L1) RSRP (and/or SL (L1) reference signal received quality (RSRQ) and/or SL (L1) received signal strength indicator (RSSI)) report request indicator, and/or   an SL CSI transmission indicator (on PSSCH) (or SL (L1) RSRP (and/or SL (L1) RSRQ and/or SL (L1) RSSI) information transmission indicator), and/or   MCS information, and/or   transmission power information, and/or   L1 destination ID information and/or L1 source ID information, and/or   SL HARQ process ID information, and/or   new data indicator (NDI) information, and/or   redundancy version (RV) information, and/or   QoS information (related to transmission traffic/packet), for example, priority information, and/or   an SL CSI-RS transmission indicator or information about the number of SL CSI-RS antenna ports (to be transmitted);   location information about a transmitting UE or location (or distance area) information about a target receiving UE (requested to transmit an SL HARQ feedback), and/or   RS (e.g., DMRS or the like) information related to decoding and/or channel estimation of data transmitted on a PSSCH, for example, information related to a pattern of (time-frequency) mapping resources of the DMRS, rank information, and antenna port index information.       

     For example, the first SCI may include information related to channel sensing. For example, the receiving UE may decode the second SCI using the PSSCH DMRS. A polar code used for the PDCCH may be applied to the second SCI. For example, the payload size of the first SCI may be equal for unicast, groupcast and broadcast in a resource pool. After decoding the first SCI, the receiving UE does not need to perform blind decoding on the second SCI. For example, the first SCI may include scheduling information about the second SCI. 
     In various embodiments of the present disclosure, since the transmitting UE may transmit at least one of the SCI, the first SCI, or the second SCI to the receiving UE on the PSCCH, the PSCCH may be replaced with at least one of the SCI, the first SCI, or the second SC. Additionally or alternatively, for example, the SCI may be replaced with at least one of the PSCCH, the first SCI, or the second SCI. Additionally or alternatively, for example, since the transmitting UE may transmit the second SCI to the receiving UE on the PSSCH, the PSSCH may be replaced with the second SCI. 
     Meanwhile, Discontinuous Reception (DRX) mechanism performs a wake-up/sleep operation, thereby enabling a low-power operation. A wake-up/sleep unit of DRX may become a slot or a subframe, and there are cycles of two types including a longDRX-cycle and a shortDRX-cycle.  FIG. 11  shows a case of a shortDRX-cycle. In case of a longDRX-cycle, it may become an integer multiple of a shortDRX-cycle and a duration to wake-up is much longer. A shortDRX-cycle indicates a cycle of repetition of wake-up/sleep, and on-duration is an interval for a UE to wake up, monitor a channel, and check whether there is a signal to receive. Namely, a presence or non-presence of connection is determined by monitoring PSCCH in each subframe/slot for every on-duration period. If a UE receives data necessary for itself for an on-duration period, the UE may receive a necessary signal by driving a DRX-inactivity timer. The DRX-inactivity timer operates on a time base. If another signal is received for a DRX-inactivity timer period, the DRX-inactivity timer is reset and then restarted to increase a data-receivable time. 
     Although a method of receiving data using such a DRX may have a loss in aspect of latency, since an RF transceiver may be turned off during a sleep period, power consumption can be reduced during the corresponding time. Hence, such a DRX mode may be usefully used for a device that requires a low-power operation. 
     Specific parameters for a DRX operation (not related to a sidelink but dealing with a case of a Uu interface only) of the current LTE are described as follows.
         DRX Cycle: This parameter indicates an interval of ‘ON time’+‘OFF time’, which is embodied in an RRC message.   onDurationTimer: This parameter indicates an interval ‘ON time’ in a DRX cycle.   drx-Inactivity timer: This parameter indicates that a UE will maintain ‘ON’ state for a prescribed long time after receiving PDCCH. During an interval in which this timer is ‘on’, the UE maintains ‘ON state’, which decreases an ‘OFF’ interval but increases an ‘ON’ interval.   drx-Retransmission timer: This parameter indicates the number of subframes of maximum consecutive PDCCH in order for a UE to maintain ‘ON state’ to stand by for retransmission that comes in after a first retransmission time.   shortDRX-Cycle: This parameter means a DRX cycle generated within an off interval of a long DRX cycle. The long DRX cycle corresponds to an integer multiple of a short DRX cycle.   drxShortCycleTimer: This parameter means the shortDRX-cycle unit number of an interval in which shortDRX-cycles are generated consecutively after expiration of ‘drx-Inactivity timer’.   drxStartOffset: This parameter means a location of a subframe in which a DRX pattern starts at a specific SFN.       

     An operating example of the whole logic that operates with the above parameters is shown in  FIG. 12 . In case of receiving a message sent to itself within an onDuration interval (e.g., 2-subframe in  FIG. 12 ) of DRX, the onDuration interval is maintained during drxInactivityTimer (e.g., a purple portion in  FIG. 12 , i.e., 3-subframe). If a message is received again in this period, the drxInactivityTimer is activated from a corresponding timing point (for 3-subframe). If there is no more message received to itself, the drxInactivityTimer operation is deactivated. Thereafter, shortDRX-Cycle is performed again for the time of drxShortCycleTimer*shortDrxCycle (15-subframe). If there is no data received for this time, a low-power UE operating in DRX expects that there will be no data received for the time being. Thus, the low-power UE wakes up in a longDRX-Cycle and then checks whether there is data sent to the low-power UE. 
     In this case, longDrxCycle (10-subframe) always operates as an integer multiple of ShortDrx-Cycle (5-subframe). In addition, regarding a timing point at which onDurationTimer is started by a DRX UE, a subframe that meets the following equation is set as a start position. 
       Case of operating in shortDRX-Cycle: [(SFN*10)+subframe number] modulo(shortDrx-Cycle)=(drxStartOffset)modulo(shortDRX-Cycle) 
       Case of operating in longDRX-Cycle: [(SFN*10)+subframe number] modulo(londDrx-Cycle)=drxStartOffset  [Equation 1]
 
     Numerous DRX patterns may be generated according to configuration of the above-described parameter values. 
     In the following description, a power saving operation (Discontinuous Reception (DRX) of a UE is not supported in Rel 16 V2X Sidelink Communication. To increase the power saving effect of a power saving (DRX operation) UE, it is a matter of course that Uu DRX configuration and sidelink DRX configuration between a BS and a power saving UE are advantageously matched/aligned/fitted/mated with each other as long as possible. In the following description, a method of aligning Uu link DRX and sidelink DRX with each other is proposed to increase a power saving effect of a power saving UE and assist information necessary for this is proposed as well. In addition, in order for a power saving UE (DRX operation) to maximize a power saving effect, a method of aligning Uu DRX and sidelink DRX with each other is proposed, assist information to align them is proposed, and a process for aligning Uu DRX and sidelink DRX using the same is proposed as well. 
     In the following description, a UE may be construed as one of a TX UE, an RX UE, a peer/target UE, a packet transmitting UE, a packet receiving UE, a sidelink DRX configuration receiving UE, a sidelink DRX configuration transmitting UE. In addition, a target UE may include a packet receiving UE or a sidelink DRX configuration receiving UE, and a TX UE may include a packet transmitting UE or a sidelink DRX configuration transmitting UE. 
     A User Equipment (UE) 2 according to one embodiment may receive a sidelink DRX configuration from a UE 1 [S 1301  in  FIG. 13 ]. Thereafter, the UE 2 may perform a DRX related operation based on the sidelink DRX configuration [S 1302  in  FIG. 13 ]. 
     Here, the sidelink DRX configuration may be determined based on Uu DRX configuration. This may be referred to as a TX centric scheme, sidelink DRX configuration and Uu DRX configuration are synchronized between a BS and the UE 1, and the UE 1 configures sidelink DRX between the UE 1 and the UE 2 based on the synchronized DRX configuration. Synchronization means that two possibly different configurations are matched/aligned/fitted/mated with each other. Therefore, as described above (i.e., a method of aligning Uu link DRX and sidelink DRX to increase a power saving effect of a power saving UE), synchronizing the Uu DRX configuration between the BS and the UE 1 means that sidelink DRX configuration and Uu DRX configuration are synchronized between the BS and the UE 1. 
     In the synchronization of the sidelink DRX configuration and the Uu DRX configuration between the BS and the UE 1, a subject of matching the sidelink DRX configuration and the Uu DRX configuration or a subject of determining sidelink DRX configuration based on Uu DRX configuration includes the BS or the UE 1. 
     Therefore, the UE 1 matches/aligns/fits/mates sidelink DRX configuration of the UE 1 with Uu DRX configuration and then transmits/forwards the matched/aligned/fitted/mated sidelink DRX configuration to the UE 2. The UE 2 may then operate based on the received/forwarded sidelink DRX configuration. 
     Alternatively, the BS matches/aligns/fits/mates sidelink DRX configuration of the UE 1 with Uu DRX configuration and the UE 1 then transmits/forwards the matched/aligned/fitted/mated sidelink DRX configuration to the UE 2. The UE 2 operates based on the received/forwarded sidelink DRX configuration. 
     The sidelink DRX configuration can be determined by the base station or UE1. If the UE 2 is in coverage or connected state, the sidelink DRX configuration may be determined by one of the BS and the UE 1. Namely, based on that the UE 2 is in the connected state, the sidelink DRX configuration may be determined by the BS or the UE 1. On the contrary, i.e., if the UE is out of coverage or is not in the connected state, the sidelink DRX configuration may be determined by the UE 1. Namely, based on that the UE 2 is not in the connected state, the sidelink DRX configuration may be determined by the UE 1. 
     Together with or independently from that the sidelink DRX configuration is determined based on Uu DRX configuration, at least one of the Uu DRX configuration and the sidelink DRX configuration may be determined based on assist information. Here, the assist information (data related information) may include one or more of QoS of data/control signal, latency requirement, UE speed, UE location, sidelink measurement, and remaining battery capacity. The respective informations will be described in detail later. 
     The assist information may be transmitted to the UE 1 by the UE 2. And/or, the assist information may be forwarded to the BS via the UE 1. Particularly, regarding this, the UE 1 forwards the aforementioned information such as assist information and the like to the BS via Uu link, and the BS may configure Uu DRX by referring to such information. 
     The UE 1 may relay the assist information received from the UE 2 via sidelink to the BS. In addition, the UE 1 may store the corresponding information and then use it to configure sidelink DRX with the UE 2 in the future. Once Uu DRX is configured between the BS and the UE 1, the UE 1 configures sidelink DRX based on the assist information received from the UE 2. Based on the assist information (information of the UE 1 and UE 2 information relayed information) forwarded from the UE 1, the BS may configure Uu DRX. The UE 1 may configure sidelink DRX based on the Uu DRX. In this case, sidelink DRX between the UE 1 and the UE 2 may be configured in a manner that the sidelink DRX configured by the UE 1 is identical to Uu DRX configuration, corresponds to a subset of the Uu DRX configuration (e.g., a subset of a DRX ON duration pattern), or overlaps with the Uu DRX configuration in part. 
     The ‘on duration’ of the sidelink DRX configuration may be a subset of ‘on duration’ of the Uu DRX configuration. Alternatively, the ‘on duration’ of the sidelink DRX configuration may overlap with the ‘on duration’ of the Uu DRX configuration at least in part. 
     The UE 2 may report sidelink DRX configuration of a peer UE to the BS, which will be described later. In addition, the BS may receive service specific DRX configuration from a Core Network (CN). 
     According to the above configuration, Uu DRX configuration and sidelink DRX configuration are effectively aligned with each other, thereby increasing a power saving effect. 
     Details of the assist information are described as follows. 
     QoS of data/control signal: QoS of a data/control signal may affect Uu DRX configuration. For example, in case that QoS of Uu link between the BS and the UE 1 is good, frequency of ‘ON duration’ of DRX may be set rare, and/or a length of an ‘ON duration’ interval may be set short. Namely, if QoS is good, it is highly probable that a desired signal may be directly received in an ‘ON duration’ interval. 
     Latency requirement: Latency requirement of a service to transmit may affect Uu DRX configuration. For example, in case that latency requirement of a service to transmit is low (i.e., in case that a required latency value is small), frequency of ‘ON duration’ of DRX may be set frequent, and/or a length of an ‘ON duration’ interval may be set long. Namely, in case that a latency requirement of a service is a small value, since a time budget from a timing point of occurrence of an event of a service to a time for actual delivery is small, an operation of frequent occurrence of ‘ON duration’ may be advantageous. 
     UE speed: A moving speed of a UE may affect Uu DRX configuration. For example, if a moving speed of a UE is fast, frequency of ‘ON duration’ of DRX may be set frequent, and/or a length of an ‘ON duration’ interval may be set long. Namely, if a moving speed of a UE is fast, occurrence of an event is frequent or a tight latency requirement may be requested. 
     UE location: A location of a UE may affect Uu DRX configuration. For example, at a specific location, an ‘ON duration’ frequency of DRX may need to be adjusted as frequent or rare or a length of ‘ON’ duration’ may need to be adjusted as long or short. For example, at a place having a fast moving speed per unit time like a highway, ‘ON duration; frequency of DRX may be generated frequently. At a place having a slow moving speed per unit time like a downtown road, ‘ON duration; frequency of DRX may be generated rarely. Alternatively, since it is highly probable that a DRX mode mainly operates in a personal mobile device, ‘ON duration’ periodicity of DRX is generated rarely or ‘ON duration’ is generated short, at a place having no ambient pedestrian like a highway. At a place having many pedestrians around like a downtown road, ‘ON duration; may be generated frequently or ‘ON duration’ may be set to operate long. 
     Sidelink measurement: A sidelink measurement result may affect Uu DRX configuration. A sidelink measurement result between UE 1 and UE 2 may be forwarded to a BS via Uu link. In this case, a sidelink measurement value may become an RSRP Value measured from a Reference Signal (RS), and the above RS may include Demodulation Reference Signal (DM RS), Sounding Reference Signal (SRS), Channel-State Information (CSI) Reference Signal (RS), Phase-Tracking Reference Signal (PTRS), Cell-specific Reference Signal (CRS), etc. In aspect of sidelink, it is advantageous that ‘ON duration’ occurs at a location where a measurement value is received as a value higher than a (predetermined) reference threshold. If a sidelink measurement value or result of UE 1 and UE 2 delivers a resource location higher than a predetermined threshold to a BS, the BS may configure an ‘ON duration’ interval between the UE 1 and the BS in consideration of the delivered resource location. 
     Remaining battery capacity: A remaining battery amount of a UE may affect Uu DRX configuration. For example, if a remaining power amount of a UE 1 is large, Uu DRX may be configured in a manner that ‘ON duration’ periodicity of DRX is generated frequently or ‘ON duration’ interval is generated long. 
     Meanwhile, according to one embodiment, Uu DRX configuration is synchronized between the BS and the UE 1, and the UE 1 forwards the synchronized DRX configuration to a counterpart UE 2 via sidelink. As described in the foregoing description of the embodiment, considering the meaning of synchronization of matching/aligning/fitting/mating two configurations with each other, synchronizing the Uu DRX configuration between the BS and the UE 1 means to synchronize/match sidelink DRX configuration and Uu DRX configuration between the BS and the UE 1. Based on the received DRX configuration, the UE 2 configures sidelink DRX between the UE 1 and the UE 2. Namely, this may be referred to as an RX centric method. 
     In case of establishing Uu DRX configuration with the BS (e.g., gNB), the UE 1 forwards necessary information (e.g., assist information) to the BS, thereby enabling the BS to refer to the information in establishing the DRX configuration. 
     In case of determining a Uu DRX pattern with the BS (e.g., gNB), the UE 1 may relay and forward information of the UE 2 to the BS. The relayed information of the UE 2 may include data related information (i.e, QoS of data/control signal, latency requirement, UE speed, UE location, sidelink measurement, remaining battery capacity). The reason why such information is forwarded to the BS is the same as why the UE 1 forwards the corresponding information for the Uu link DRX configuration. The BS may configure Uu DRX in consideration of ‘information related to the UE 1’ and ‘information of the UE 2 relayed by the UE 1’. 
     Using the above-described information, Uu DRX may be configured between the BS and the UE 1. If the UE 1 forwards the Uu DRX configuration established between the BS and the UE 1 to the UE 2, the UE 2 may configure sidelink DRX between the UE 1 and the UE 2 in a manner that the sidelink DRX is identical to Uu DRX configuration, corresponds to a subset of the Uu DRX configuration (e.g., a subset of a DRX ON duration pattern), or overlaps with the Uu DRX configuration in part. 
     According to another embodiment, sidelink DRX configuration is synchronized between the UE 1 and the UE 2 and the UE informs the BS of such synchronization. The BS may (re)configure Uu link DRX by referring to the sidelink DRX configuration. 
     The UE 1 and the UE 2 may exchange assist information (data related information) (e.g., QoS of data/control signal, latency requirement, UE speed, UE location, sidelink measurement, remaining battery capacity, etc.) possibly necessary to configure DRX with each other and then configure sidelink DRX through negotiation. 
     Once the sidelink DRX is configured/synchronized between the UE 1 and the UE 2, such configuration/synchronization is forwarded to the BS via Uu link. Based on the sidelink DRX value forwarded from the UE 1, the BS may configure Uu DRX between the UE 1 and the BS. In this case, the Uu DRX between the BS and the UE 1 may be configured in a manner of being configured identical to the preconfigured sidelink DRX, corresponding to a subset of the sidelink DRX configuration (e.g., a subset of a DRX ON duration pattern), or overlapping with the sidelink DRX configuration in part. 
     As shown in  FIG. 15 , an embodiment related to a case that each of a UE 1 and a UE 2 are connected to a BS via Uu link and that the UE 1 and the UE 2 are connected to each other via sidelink is described in the following. 
     According to one embodiment, Uu DRX is configured between the BS and each of the UE 1 and the UE 2. The UE 1 and UE 2 configure sidelink DRX based on the Uu DRXs of their own. Based on the configured sidelink DRX, the UE 1 and/or the UE 2 may make a request for Uu DRX (re)configuration of its own to the BS. In this case, when the UE 1 or UE 2 forwards the sidelink DRX via Uu link of its own, it may forward ID of a counterpart UE having sidelink RRC connection to the corresponding UE 1 or UE 2 as well. 
     Uu DRX may be configured in a manner of exchanging information such as assist information and the like between the BS and the UE 1. Uu DRX configuration may be configured in a manner of exchanging information such as assist information and the like between the BS and the UE 2. 
     After the Uu DRX has been configured between the BS and each of the UE 1 and the UE 2, the UE 1 and the UE 2 may exchange additional assist information (data related information), e.g., QoS of data/control signal, latency requirement, UE speed, UE location, sidelink measurement, remaining battery capacity and the like with each other as well as the Uu DRX configuration information between the BS and each of the UE 1 and the UE 2, or configure sidelink DRX based on such information. In this case, the configured sidelink DRX may include configuration having the common property of the predetermined Uu DRX configuration or configuration matching with specific Uu DRX configuration completely/partially. 
     Once the sidelink DRX is configured/synchronized, each of the UE 1 and the UE 2 may forward the sidelink DRX configuration to the BS via the Uu link of its own. Based on the sidelink DRX value forwarded from each UE, the BS may (re)configure Uu DRX of each of the UE 1 and the UE 2. Alternatively, a specific one of the UE 1 and the UE 2, e.g., a UE having a bigger/smaller ID may forward a layer 2 ID of a counterpart UE having a sidelink RRC connection to the specific UE and sidelink DRX configured with the counterpart UE to the BS via Uu link of its own. Having received the corresponding information, the BS may (re)configure DRX of Uu link between the UE having forwarded the information and the counterpart UE. 
       FIG. 16  illustrates a case that a UE 1 and a UE 2 are connected to different BSs via Uu links, respectively and that the UE 1 and the UE 2 are connected together via sidelink. Regarding this, one Uu DRX is configured between the BS and the UE 1, the other Uu DRX is configured between the BS and the UE 2, and the UE 1 and the UE 2 configure sidelink DRX based on the Uu DRXs of their own. Based on the configured sidelink DRX, the UE 1 and/or the UE 2 may make a resource for its Uu DRX (re)configuration to the BS. In this case, when the UE 1 or the UE 2 forwards sidelink DRX via Uu link of its own, the corresponding UE may forward an ID of a counterpart UE having sidelink RRC connection to the corresponding UE and an ID of a BS having a Uu link with the counterpart UE together. 
     Uu DRX may be configured between a BS A and the UE 1 by exchanging information such as assist information and the like. Uu DRX may be configured between a BS B and the UE 2 by exchanging information such as assist information and the like. 
     After the Uu DRX between the BS A and the UE 1 and the Uu DRX between the BS B and the UE 2 have been configured, each of the UE 1 and the UE 2 may exchange additional assist information (data related information), e.g., QoS of data/control signal, latency requirement, UE speed, UE location, sidelink measurement, remaining battery capacity and the like with each other as well as the Uu DRX configuration information between the BS and each of the UE 1 and the UE 2, or configure sidelink DRX based on such informations. In this case, the configured sidelink DRX may include configuration having the common property of the predetermined Uu DRX configuration or configuration matching with specific Uu DRX configuration completely/partially. 
     Once the sidelink DRX is configured/synchronized, each of the UE 1 and the UE 2 may forward the sidelink DRX configuration to the BS via the Uu link of its own. Based on the sidelink DRX value forwarded from each UE, the BSs may (re)configure Uu DRXs of the UE 1 and the UE 2, respectively. Alternatively, a specific one of the UE 1 and the UE 2, e.g., a UE having a bigger/smaller ID may forward a layer 2 ID of a counterpart UE having a sidelink RRC connection to the specific UE, an ID of a BS having a Uu link to the counterpart UE, and sidelink DRX configured with the counterpart UE to the corresponding BS via Uu link of its own. Having received the corresponding information, the BS may forward the received information to the BS having the connection with the counterpart UE and (re)configure DRX of Uu link connected to itself using the received information. 
     Describe in the following is a method of aligning DRX configuration (pattern) applicable together with or independently from the above-described embodiments. The following description may use the resource allocation scheme of a UE to communicate with as well as the method proposed in the foregoing description. 
     According to one embodiment, if a TX UE obtains sidelink DRX configuration of surrounding target UE(s) including/excluding itself and reports it to a B S, the TX UE may operate in a manner of expecting to receive allocation of a resource corresponding to surrounding sidelink DRX on-duration from the BS. This embodiment may be related to a mode-I operation. 
     A discovery message may contain sidelink DRX configuration, and the TX UE connected to the BS may obtain sidelink DRX configuration of surrounding target UE(s) through the discovery message. 
     The TX UE reports the obtained sidelink DRX configuration of the surrounding UE to the BS and then operates in a manner of expecting that the BS will consider it for the resource allocation of the TX UE. In this case, the sidelink DRX configuration transmitted to the BS by the TX UE may include an individual value of a value obtained from the surrounding UE or a new value provided as a sum of specific information. For example, new sidelink DRX configuration (pattern) resulting from applying an OR-operation (i.e., union-operation) to an on-duration interval only may be forwarded to the BS. 
     According to one embodiment, a TX UE forwards resource pool (allocation) information received from a BS to surrounding target UE(s). The target UE(s) then generates sidelink DRX configuration correspondingly. This embodiment may be related to a mode-1 operation. 
     The TX UE may broadcast the resource pool (application) information received from the BS to the surrounding target UE(s) through a discovery message or SCI. 
     Once the resource allocation information received from the BS is reconfigured, the TX UE forwards it to the target UE(s). And, the target UE(s) may reconfigure sidelink DRX configuration correspondingly. 
     According to one embodiment, dedicated (pre)configured resource pool (resource allocation) information of target UE(s) is obtained and sidelink DRX configuration of its own is generated correspondingly. The (pre)configured resource pool information of target UE(s) to perform communication may be obtained through a discovery message or SCI. By observing an on-duration part of the obtained resource pool information(s) of the target UE(s), sidelink DRX configuration (on-duration interval) of its own may be configured in a part corresponding to a common on-duration region (e.g., intersection) or a prescribed on-duration region (e.g., union). This embodiment may be related to a mode-2 operation. 
     According to one embodiment, a TX UE forwards dedicated (pre)configured resource pool (resource allocation) information to surrounding target UE(s) and the target UE(s) generate sidelink DRX configuration of its own correspondingly. A TX UE may forward (pre)configured resource pool information of its own to surrounding target UE(s) through a discovery message or SCI. The target UE(s) may form sidelink DRX configuration of its own using the resource pool information obtained from the TX UE. This embodiment may be related to a mode-2 operation. 
     A Core Network (CN) may inform a BS of specific DRX configuration information according to service/geographical-area/zone-ID/group-ID and the like together with UE (e.g., personal UE) authorization. A BS may inform a UE of such DRX configuration information in making a paging transmission or through RRC when a connected mode starts. 
     DRX configuration information may be determined as a specific value according to service/geographical-area/zone-ID/group-ID and the like, and the determined DRX configuration information may be transmitted to a UE from a BS. When the UE is in IDLE mode, a paging signal may be transmitted in a manner of containing such DRX configuration. When the UE is in CONNECTED mode, such DRX configuration may be indicated through RRC. Using the received service/geographical-area/zone-ID/group-ID specific DRX configuration information, the UE may establish DRX IPRconfiguration of its own. Since UE(s) using the same service, UE(s) belonging to a specific geographical-area, UE(s) belonging to the same zone-ID, or UE belonging to the same group-ID(s) may be aware of mutually operating DRX configuration, the above-established DRX configuration may facilitate alignment of an on-duration interval. 
     Examples of Communication Systems Applicable to the Present Disclosure 
     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. 17  illustrates a communication system  1  applied to the present disclosure. 
     Referring to  FIG. 17 , a communication system  1  applied to the present disclosure includes wireless devices, BSs, and a network. Herein, the wireless devices represent devices performing communication using RAT (e.g., 5G NR or 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 driving 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. 
     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. V2V/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 UL/DL 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. 
     Examples of Wireless Devices Applicable to the Present Disclosure 
       FIG. 18  illustrates wireless devices applicable to the present disclosure. 
     Referring to  FIG. 18 , 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. 17 . 
     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. 
     Examples of a Vehicle or an Autonomous Driving Vehicle Applicable to the Present Disclosure 
       FIG. 19  illustrates a vehicle or an autonomous driving vehicle applied to the present disclosure. The vehicle or autonomous driving vehicle may be implemented by a mobile robot, a car, a train, a manned/unmanned aerial vehicle (AV), a ship, etc. 
     Referring to  FIG. 19 , a vehicle or autonomous driving 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 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 driving vehicle  100 . The control unit  120  may include an ECU. The driving unit  140   a  may cause the vehicle or the autonomous driving 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 driving 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 driving 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 driving vehicles and provide the predicted traffic information data to the vehicles or the autonomous driving vehicles. 
     Examples of a Vehicle and AR/VR Applicable to the Present Disclosure 
       FIG. 20  illustrates a vehicle applied to the present disclosure. The vehicle may be implemented as a transport means, an aerial vehicle, a ship, etc. 
     Referring to  FIG. 20 , a vehicle  100  may include a communication unit  110 , a control unit  120 , a memory unit  130 , an I/O unit  140   a , and a positioning unit  140   b.    
     The communication unit  110  may transmit and receive signals (e.g., data and control signals) to and from external devices such as other vehicles or BSs. The control unit  120  may perform various operations by controlling constituent elements of the vehicle  100 . The memory unit  130  may store data/parameters/programs/code/commands for supporting various functions of the vehicle  100 . The I/O unit  140   a  may output an AR/VR object based on information within the memory unit  130 . The I/O unit  140   a  may include an HUD. The positioning unit  140   b  may acquire information about the position of the vehicle  100 . The position information may include information about an absolute position of the vehicle  100 , information about the position of the vehicle  100  within a traveling lane, acceleration information, and information about the position of the vehicle  100  from a neighboring vehicle. The positioning unit  140   b  may include a GPS and various sensors. 
     As an example, the communication unit  110  of the vehicle  100  may receive map information and traffic information from an external server and store the received information in the memory unit  130 . The positioning unit  140   b  may obtain the vehicle position information through the GPS and various sensors and store the obtained information in the memory unit  130 . The control unit  120  may generate a virtual object based on the map information, traffic information, and vehicle position information and the I/O unit  140   a  may display the generated virtual object in a window in the vehicle ( 1410  and  1420 ). The control unit  120  may determine whether the vehicle  100  normally drives within a traveling lane, based on the vehicle position information. If the vehicle  100  abnormally exits from the traveling lane, the control unit  120  may display a warning on the window in the vehicle through the I/O unit  140   a . In addition, the control unit  120  may broadcast a warning message regarding driving abnormity to neighboring vehicles through the communication unit  110 . According to situation, the control unit  120  may transmit the vehicle position information and the information about driving/vehicle abnormality to related organizations. 
     Examples of an XR Device Applicable to the Present Disclosure 
       FIG. 21  illustrates an XR device applied to the present disclosure. The XR device may be implemented by an HMD, an HUD mounted in a vehicle, a television, a smartphone, a computer, a wearable device, a home appliance, a digital signage, a vehicle, a robot, etc. 
     Referring to  FIG. 21 , an XR device  100   a  may include a communication unit  110 , a control unit  120 , a memory unit  130 , an I/O unit  140   a , a sensor unit  140   b , and a power supply unit  140   c.    
     The communication unit  110  may transmit and receive signals (e.g., media data and control signals) to and from external devices such as other wireless devices, hand-held devices, or media servers. The media data may include video, images, and sound. The control unit  120  may perform various operations by controlling constituent elements of the XR device  100   a . For example, the control unit  120  may be configured to control and/or perform procedures such as video/image acquisition, (video/image) encoding, and metadata generation and processing. The memory unit  130  may store data/parameters/programs/code/commands needed to drive the XR device  100   a /generate XR object. The I/O unit  140   a  may obtain control information and data from the exterior and output the generated XR object. The I/O unit  140   a  may include a camera, a microphone, a user input unit, a display unit, a speaker, and/or a haptic module. The sensor unit  140   b  may obtain an XR device state, surrounding environment information, user information, etc. The sensor unit  140   b  may include a proximity sensor, an illumination sensor, an acceleration sensor, a magnetic sensor, a gyro sensor, an inertial sensor, an RGB sensor, an IR sensor, a fingerprint recognition sensor, an ultrasonic sensor, a light sensor, a microphone and/or a radar. The power supply unit  140   c  may supply power to the XR device  100   a  and include a wired/wireless charging circuit, a battery, etc. 
     For example, the memory unit  130  of the XR device  100   a  may include information (e.g., data) needed to generate the XR object (e.g., an AR/VR/MR object). The I/O unit  140   a  may receive a command for manipulating the XR device  100   a  from a user and the control unit  120  may drive the XR device  100   a  according to a driving command of a user. For example, when a user desires to watch a film or news through the XR device  100   a , the control unit  120  transmits content request information to another device (e.g., a hand-held device  100   b ) or a media server through the communication unit  130 . The communication unit  130  may download/stream content such as films or news from another device (e.g., the hand-held device  100   b ) or the media server to the memory unit  130 . The control unit  120  may control and/or perform procedures such as video/image acquisition, (video/image) encoding, and metadata generation/processing with respect to the content and generate/output the XR object based on information about a surrounding space or a real object obtained through the I/O unit  140   a /sensor unit  140   b.    
     The XR device  100   a  may be wirelessly connected to the hand-held device  100   b  through the communication unit  110  and the operation of the XR device  100   a  may be controlled by the hand-held device  100   b . For example, the hand-held device  100   b  may operate as a controller of the XR device  100   a . To this end, the XR device  100   a  may obtain information about a 3D position of the hand-held device  100   b  and generate and output an XR object corresponding to the hand-held device  100   b.    
     Examples of a Robot Applicable to the Present Disclosure 
       FIG. 49  illustrates a robot applied to the present disclosure. The robot may be categorized into an industrial robot, a medical robot, a household robot, a military robot, etc., according to a used purpose or field. 
     Referring to  FIG. 49 , a robot  100  may include a communication unit  110 , a control unit  120 , a memory unit  130 , an I/O unit  140   a , a sensor unit  140   b , and a driving unit  140   c.    
     The communication unit  110  may transmit and receive signals (e.g., driving information and control signals) to and from external devices such as other wireless devices, other robots, or control servers. The control unit  120  may perform various operations by controlling constituent elements of the robot  100 . The memory unit  130  may store data/parameters/programs/code/commands for supporting various functions of the robot  100 . The I/O unit  140   a  may obtain information from the exterior of the robot  100  and output information to the exterior of the robot  100 . The I/O unit  140   a  may include a camera, a microphone, a user input unit, a display unit, a speaker, and/or a haptic module. The sensor unit  140   b  may obtain internal information of the robot  100 , surrounding environment information, user information, etc. The sensor unit  140   b  may include a proximity sensor, an illumination sensor, an acceleration sensor, a magnetic sensor, a gyro sensor, an inertial sensor, an IR sensor, a fingerprint recognition sensor, an ultrasonic sensor, a light sensor, a microphone, a radar, etc. The driving unit  140   c  may perform various physical operations such as movement of robot joints. In addition, the driving unit  140   c  may cause the robot  100  to travel on the road or to fly. The driving unit  140   c  may include an actuator, a motor, a wheel, a brake, a propeller, etc. 
     Example of AI Device to which the Present Disclosure is Applied. 
       FIG. 23  illustrates an AI device applied to the present disclosure. The AI device may be implemented by a fixed device or a mobile device, such as a TV, a projector, a smartphone, a PC, a notebook, a digital broadcast terminal, a tablet PC, a wearable device, a Set Top Box (STB), a radio, a washing machine, a refrigerator, a digital signage, a robot, a vehicle, etc. 
     Referring to  FIG. 23 , an AI device  100  may include a communication unit  110 , a control unit  120 , a memory unit  130 , an I/O unit  140   a / 140   b , a learning processor unit  140   c , and a sensor unit  140   d.    
     The communication unit  110  may transmit and receive wired/radio signals (e.g., sensor information, user input, learning models, or control signals) to and from external devices such as other AI devices (e.g.,  100   x ,  200 , or  400  of  FIG. 17 ) or an AI server (e.g.,  400  of  FIG. 17 ) using wired/wireless communication technology. To this end, the communication unit  110  may transmit information within the memory unit  130  to an external device and transmit a signal received from the external device to the memory unit  130 . 
     The control unit  120  may determine at least one feasible operation of the AI device  100 , based on information which is determined or generated using a data analysis algorithm or a machine learning algorithm. The control unit  120  may perform an operation determined by controlling constituent elements of the AI device  100 . For example, the control unit  120  may request, search, receive, or use data of the learning processor unit  140   c  or the memory unit  130  and control the constituent elements of the AI device  100  to perform a predicted operation or an operation determined to be preferred among at least one feasible operation. The control unit  120  may collect history information including the operation contents of the AI device  100  and operation feedback by a user and store the collected information in the memory unit  130  or the learning processor unit  140   c  or transmit the collected information to an external device such as an AI server ( 400  of  FIG. 17 ). The collected history information may be used to update a learning model. 
     The memory unit  130  may store data for supporting various functions of the AI device  100 . For example, the memory unit  130  may store data obtained from the input unit  140   a , data obtained from the communication unit  110 , output data of the learning processor unit  140   c , and data obtained from the sensor unit  140 . The memory unit  130  may store control information and/or software code needed to operate/drive the control unit  120 . 
     The input unit  140   a  may acquire various types of data from the exterior of the AI device  100 . For example, the input unit  140   a  may acquire learning data for model learning, and input data to which the learning model is to be applied. The input unit  140   a  may include a camera, a microphone, and/or a user input unit. The output unit  140   b  may generate output related to a visual, auditory, or tactile sense. The output unit  140   b  may include a display unit, a speaker, and/or a haptic module. The sensing unit  140  may obtain at least one of internal information of the AI device  100 , surrounding environment information of the AI device  100 , and user information, using various sensors. The sensor unit  140  may include a proximity sensor, an illumination sensor, an acceleration sensor, a magnetic sensor, a gyro sensor, an inertial sensor, an RGB sensor, an IR sensor, a fingerprint recognition sensor, an ultrasonic sensor, a light sensor, a microphone, and/or a radar. 
     The learning processor unit  140   c  may learn a model consisting of artificial neural networks, using learning data. The learning processor unit  140   c  may perform AI processing together with the learning processor unit of the AI server ( 400  of  FIG. 17 ). The learning processor unit  140   c  may process information received from an external device through the communication unit  110  and/or information stored in the memory unit  130 . In addition, an output value of the learning processor unit  140   c  may be transmitted to the external device through the communication unit  110  and may be stored in the memory unit  130 . 
     INDUSTRIAL APPLICABILITY 
     The above-described embodiments of the present disclosure are applicable to various mobile communication systems. 
     Accordingly, embodiments of the present disclosure provide various effects and/or features. 
     According to one embodiment, Uu DRX configuration and sidelink DRX configuration are effectively aligned, thereby increasing a power saving effect. 
     It will be appreciated by those skilled in the art that various modifications and variations can be made in the present disclosure without departing from the spirit or scope of the disclosures. Thus, it is intended that the present disclosure covers the modifications and variations of this disclosure provided they come within the scope of the appended claims and their equivalents.