Method and apparatus for handling integrity of remote UE packets transmitted through UE repeater in wireless communication system

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate.

Description

Technical Field

[0001] The present disclosure relates to a wireless communication system. More specifically, the present disclosure relates to a method and apparatus for handling integrity of packets transmitted by a relay by a UE, the UE establishing a connection with another UE based on a side link with a relay UE and transmitting and receiving packets through a relay of the relay UE. Background Art

[0002] 5G mobile communication technology defines a wide frequency band, making high transmission rates and new services possible, and can be realized not only in "below 6 GHz" frequency bands such as 3.5 GHz, but also in "above 6 GHz" frequency bands (including 28 GHz and 39 GHz) called millimeter waves. In addition, implementation of 6G mobile communication technology (called super 5G system) in terahertz frequency bands (for example, 95 GHz to 3 THz bands) has been considered in order to achieve transmission rates fifty times faster than 5G mobile communication technology and ultra-low latency one-tenth of 5G mobile communication technology.

[0003] At the beginning of the development of 5G mobile communication technology, in order to support services and meet performance requirements related to enhanced mobile broadband (eMBB), ultra-reliable and low-latency communications (URLLC) and massive machine type communications (mMTC), standardization has been carried out on the following technologies: beamforming and massive massive MIMO for reducing radio wave path loss and increasing radio wave transmission distance in millimeter waves; supporting parameters for dynamic operation of efficient utilization of millimeter wave resources and time slot formats (for example, operating multiple subcarrier spacings); initial access technology for supporting multi-beam transmission and wide frequency bands; definition and operation of BWP (bandwidth part); new channel coding methods such as LDPC (low-density parity check) codes for large-scale data transmission and polar codes for highly reliable transmission of control information; L2 preprocessing; and network slicing for providing dedicated networks dedicated to specific services.

[0004] Currently, with respect to services supported by 5G mobile communication technology, the industry is continuously discussing improvements and performance enhancements on initial 5G mobile communication technology, and has completed physical layer standardization on technologies such as: V2X (Vehicle-to-Everything) for assisting driving decisions based on information about the location and status of a vehicle sent by a vehicle and for improving user convenience, NR-U (New Radio Unlicensed) for system operations that comply with various regulatory-related requirements in unlicensed frequency bands, NR UE energy saving, non-terrestrial network (NTN) for UE satellite direct communication for ensuring coverage in areas where communication with terrestrial networks is not possible, and positioning.

[0005] In addition, the standardization of air interface architecture / protocols for technologies such as the Industrial Internet of Things (IIOT) for supporting new services through interworking and integration with other industries, IAB (Integrated Access and Backhaul) for providing nodes for network service area expansion by supporting wireless backhaul links and access links in an integrated manner, mobility enhancements including conditional handover and DAPS (Dual Active Protocol Stack) handover, and two-step random access (2-step RACH for NR) for simplifying the random access process. At the same time, the standardization of system architecture / services for technologies such as the 5G baseline architecture (e.g., service-based architecture or service-based interface) for combining network function virtualization (NFV) and software defined network (SDN) technologies, and mobile edge computing (MEC) for receiving services based on UE location is also advancing.

[0006] With the commercialization of 5G mobile communication systems, an exponentially growing number of connected devices will be connected to the communication network, and it is therefore expected that enhanced functions and performance of 5G mobile communication systems and integrated operations of connected devices will be necessary. To this end, new research on the following technologies is on the agenda: extended reality (XR) for efficient support of AR (augmented reality), VR (virtual reality), MR (mixed reality), etc.; 5G performance improvement and complexity reduction by utilizing artificial intelligence (AI) and machine learning (ML); AI service support; metaverse service support; and drone communication.

[0007] Furthermore, such developments in 5G mobile communication systems will lay the foundation not only for the development of new waveforms for providing coverage in the terahertz band of 6G mobile communication technology; multi-antenna transmission technologies such as full-dimensional MIMO (FD-MIMO), array antennas, and massive antennas; metamaterial-based lenses and antennas for improving coverage of terahertz band signals; high-dimensional spatial multiplexing technology using OAM (orbital angular momentum); and RIS (reconfigurable smart surfaces), but will also lay the foundation for the development of full-duplex technology for improving the frequency efficiency of 6G mobile communication technology and improving system networks; AI-based communication technology for achieving system optimization from the design stage by leveraging satellites and AI (artificial intelligence) and internalizing end-to-end AI support functions; and next-generation distributed computing technology for achieving services at a complexity level that exceeds the limits of UE operating capabilities by leveraging ultra-high-performance communication and computing resources.

[0008] In addition, direct communication (sidelink communication) between terminals using the 5G communication system is being studied, and it is expected that the sidelink communication can be applied to, for example, vehicle-to-everything (V2X) communication and public safety networks, thereby providing various services to users.

[0009] In particular, there is a need for a method of utilizing a sidelink repeater that can support expanding service coverage, increasing data transmission reliability, and reducing power consumption of a terminal. Summary of the invention

[0010] Technical issues

[0011] The embodiments of the present disclosure are to provide an apparatus and method capable of effectively providing services in a wireless communication system.

[0012] The technical objectives to be achieved in the present disclosure are not limited to those mentioned above, and other unmentioned technical objectives will be clearly understood by ordinary technicians in the technical field to which the present disclosure belongs from the following description.

[0013] Problem Solution

[0014] In the present disclosure, in order to solve the above problems, a method performed by a first UE in a wireless communication system may include: detecting a packet data convergence protocol (PDCP) integrity check failure; detecting a sidelink radio link failure (RLF) caused by the PDCP integrity check failure; releasing a sidelink connection with a second UE in response to the sidelink radio link failure; and transmitting a message to a relay UE notifying the sidelink radio link failure caused by the PDCP integrity check failure.

[0015] In an embodiment, the second UE may transmit a message notifying the side link radio link failure due to PDCP integrity check failure to the relay UE.

[0016] In an embodiment, releasing the sidelink connection with the second UE may include at least one of: releasing a data radio bearer (DRB) for the second UE, releasing a signaling radio bearer (SRB) for the second UE, releasing configuration information configured for transmitting and receiving data and signaling for the second UE, or releasing a PC5 radio resource control (RRC) connection with the second UE.

[0017] In an embodiment, the relay UE may perform a process for releasing sidelink relay configuration information of the first UE and the second UE, resetting the sidelink medium access control (MAC), and releasing or reestablishing the sidelink radio link control (RLC) based on the message.

[0018] Additionally, in another embodiment of the present disclosure, a method performed by a second UE in a wireless communication system may include: releasing a sidelink connection with the first UE in response to a sidelink radio link failure (RLF) at the first UE; and transmitting a message to a relay UE notifying of a sidelink radio link failure due to a packet data convergence protocol (PDCP) integrity check failure, wherein the PDCP integrity check failure can be detected by the first UE, and the sidelink radio link failure can be detected due to the PDCP integrity check failure.

[0019] Additionally, in another embodiment of the present disclosure, a first UE in a wireless communication system may include: a transceiver capable of transmitting and receiving at least one signal; and a controller connected to the transceiver, wherein the controller may be configured to: detect a packet data convergence protocol (PDCP) integrity check failure; detect a sidelink radio link failure (RLF) caused by a PDCP integrity check failure; release a sidelink connection with a second UE in response to the sidelink radio link failure; and transmit a message to a relay UE notifying of a sidelink radio link failure caused by a PDCP integrity verification failure.

[0020] Additionally, in another embodiment of the present disclosure, a second UE in a wireless communication system may include: a transceiver capable of transmitting and receiving at least one signal; and a controller connected to the transceiver, wherein the controller may be configured to: release a sidelink connection with the first UE in response to a sidelink radio link failure (RLF) at the first UE; and transmit a message to a relay UE notifying of a sidelink radio link failure due to a packet data convergence protocol (PDCP) integrity check failure, wherein the PDCP integrity check failure may be detected by the first UE, and the sidelink radio link failure may be detected due to the PDCP integrity check failure.

[0021] The present disclosure relates to a method and device for processing integrity protection of data or signaling of a UE in a system that relays data or signaling between UEs based on a side link with a relay UE in a wireless communication system. According to an embodiment of the present disclosure, a method performed by a transmitting UE in a wireless communication system may include: checking whether PDCP PDU integrity protection is set to be applied to data or signaling to be transmitted, and transmitting the data or signaling to a receiving UE with or without applying PDCP PDU integrity protection to the data or signaling; receiving signaling indicating PDCP PDU integrity protection failure of the data or signaling from the receiving UE; triggering PDCP reestablishment with the receiving UE; performing authentication and security setup procedures for integrity protection with the receiving UE during the PDCP reestablishment process with the receiving UE; and performing procedures for MAC reset and RLC reestablishment or RLC release using a side link relay that relays data or signaling for the receiving UE.

[0022] According to an embodiment of the present disclosure, a method performed by a receiving UE in a wireless communication system may include: checking whether PDCP PDU integrity protection is set to be applied to data or signaling received from a transmitting UE, and when data or signaling is received from the transmitting UE, determining whether the PDCP PDU integrity protection of the corresponding packet is successful or failed; when it is determined that a PDCP PDU integrity failure has occurred, indicating the PDCP PDU integrity failure to a higher layer; deleting a received packet determined to be a PDCP PDU integrity failure; transmitting a signaling notifying the PDCP PDU integrity failure to the transmitting UE; triggering PDCP reestablishment with the transmitting UE; during the PDCP reestablishment process with the transmitting UE, performing an authentication and security setup process for integrity protection with the transmitting UE; and performing a process for MAC reset and RLC reestablishment or RLC release using a sidelink repeater that relays data or signaling for the transmitting UE.

[0023] According to an embodiment of the present disclosure, a method performed by a sidelink repeater in a wireless communication system may include: receiving signaling from a transmitting UE or a receiving UE indicating that the sidelink repeater needs to be reconfigured due to a PDCP PDU integrity failure; and performing a process for sidelink MAC reset and sidelink RLC reconstruction or sidelink RLC release with the transmitting UE or the receiving UE.

[0024] Advantageous Effects of the Invention

[0025] According to an embodiment of the present disclosure, an apparatus and method for effectively providing a service and expanding a service range in a wireless communication system may be provided.

[0026] Effects obtainable from the present disclosure are not limited to those mentioned above, and other unmentioned effects will be clearly understood from the following description by those having ordinary skill in the art to which the present disclosure pertains. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1A is a diagram illustrating a wireless communication system according to an embodiment of the present disclosure.

[0028] Figure 1B is a diagram illustrating a wireless communication system according to an embodiment of the present disclosure.

[0029] Figure 2 is a diagram showing a structure of a base station in a wireless communication system according to an embodiment of the present disclosure.

[0030] Figure 3 is a diagram showing a structure of a UE in a wireless communication system according to an embodiment of the present disclosure.

[0031] Figure 4 is a diagram showing a structure of a communication unit in a wireless communication system according to an embodiment of the present disclosure.

[0032] Figure 5 is a diagram showing the structure of time-frequency resources in a wireless communication system according to an embodiment of the present disclosure.

[0033] Figure 6 is a diagram illustrating a process for processing configuration information for relaying signaling and data in a wireless communication system according to an embodiment of the present disclosure, wherein a UE and another UE communicate through a sidelink relay.

[0034] Figure 7 is a diagram illustrating a process for processing configuration information for transmitting and receiving signaling and data in a wireless communication system according to an embodiment of the present disclosure, in which direct communication is performed between UEs.

[0035] Figure 8 is a diagram illustrating a process for handling integrity protection of signaling packets received through a sidelink repeater according to an embodiment of the present disclosure.

[0036] Fig. 9 is a diagram illustrating a process for handling integrity protection of signaling packets received through a sidelink repeater according to an embodiment of the present disclosure.

[0037] Fig.10 is a diagram illustrating a process for handling integrity protection of signaling packets received through a sidelink repeater according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0038] Hereinafter, the preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In this case, it should be noted that in the accompanying drawings, the same components are indicated by the same symbols as much as possible. In addition, the detailed description of well-known functions or configurations that may obscure the subject matter of the present disclosure will be omitted.

[0039] When describing the embodiments in this specification, descriptions of technical contents known in the field to which the present disclosure belongs and not directly related to the present disclosure are omitted, that is, the key points of the present disclosure are conveyed more clearly by omitting unnecessary descriptions without blurring the key points.

[0040] For the same reason, some parts in the drawings are enlarged, omitted or schematically depicted. In addition, the size of the parts does not necessarily reflect the actual size. In the drawings, the same or corresponding parts are given the same reference numerals.

[0041] The advantages and features of the present disclosure and methods for achieving them will become clear with reference to the embodiments described in detail below in conjunction with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below and can be implemented in various different forms, and the embodiments of the present invention are provided only to make the present disclosure complete and fully inform the scope of the present disclosure to those of ordinary skill in the art to which the present disclosure belongs, and the present disclosure is limited only by the scope of the claims. Throughout this specification, the same reference numerals refer to the same components.

[0042] At the same time, it will be understood that the blocks in the combination of the flowchart and the flowchart can be executed by computer program instructions. These computer program instructions can be loaded on a processor of a general-purpose computer, a special-purpose computer, or a programmable data processing device, and the instructions executed by the processor of the computer or the programmable data processing device produce a device for performing the functions detailed in the blocks of the flowchart. In order to implement the functions in a particular way, the computer program instructions can also be stored in a computer-available or readable memory suitable for a special-purpose computer or a programmable data processing device, and the computer program instructions stored in the computer-available or readable memory can produce a product containing a device for performing the functions described in the blocks of the flowchart. Since the computer program instructions can be loaded on a computer or a programmable data processing device, when the computer program instructions are executed on a computer or a programmable data processing device as a process with a series of operations, they can provide steps for performing the functions described in the blocks of the flowchart.

[0043] In addition, each block of the flowchart may correspond to a module, segment or code containing one or more executable instructions for performing one or more logical functions, or to a portion thereof. It should also be noted that in some alternative cases, the functions described by the blocks may be performed in an order different from the order listed. For example, two blocks listed in sequence may be performed substantially simultaneously or in reverse order, depending on the corresponding functions.

[0044] Here, the words "unit", "module", etc. used in the embodiment may refer to software components or hardware components that can perform functions or operations, such as FPGA (field programmable gate array) or ASIC (application-specific integrated circuit). However, "unit", etc. are not limited to hardware or software. Units, etc. may be configured to reside in an addressable storage medium or drive one or more processors. For example, units, etc. may refer to components such as software components, object-oriented software components, category components or task components, processes, functions, attributes, programs, subroutines, program code segments, drivers, firmware, microcodes, circuits, data, databases, data structures, tables, arrays, or variables. The functions provided by components and units may be a combination of smaller components and units, and it may be combined with other functions to form larger components and units. Components and units may be implemented to drive one or more central processing units (CPUs) in a device or a secure multimedia card.

[0045] When explaining the embodiments of the present disclosure specifically, the main target is a new RAN (NR) radio access network and a packet core, which is a core network (5G system, or 5G core network, or NG core: Next Generation Core) on the 5G mobile communication standard specified by 3GPP as a mobile communication standardization organization. However, without departing from the scope of the present disclosure, the main points of the present disclosure may be slightly modified and applied to other communication systems with similar technical backgrounds, and this will be possible at the discretion of those skilled in the art in the field of the present disclosure.

[0046] In the 5G system, in order to support network automation, a network data collection and analysis function (NWDAF) can be defined, which is a network function (NF) that analyzes data collected from the 5G network and provides analysis results. The NWDAF can collect / store / analyze information from the 5G network and provide the results to non-specified network functions (NFs), and the analysis results can be used independently by each NF.

[0047] For the convenience of the following explanation, some terms and names defined in 3GPP (3rd Generation Partnership Project Long Term Evolution) standards (standards for 5G, NR, LTE or similar systems) may be used. However, the present disclosure is not limited to these terms and names and can be equally applied to systems conforming to other standards.

[0048] The present disclosure relates to a method and apparatus for handling integrity of packets transmitted and received through relay transmission of a sidelink relay when the UE is connected to another UE through the sidelink relay in a wireless communication system.

[0049] Embodiments of the present disclosure may expand service coverage, increase reliability of data transmission and reception, and minimize battery usage of the UE by allowing a UE to transmit and receive data / signaling to and from another UE through a sidelink relay.

[0050] The terms used to refer to signals, channels, control information, network entities and device components in the following description are for the purpose of explanation. Therefore, the present disclosure is not limited to the terms used, and other terms referring to subjects with equivalent technical meanings may be used.

[0051] In the following description, the base station is a subject that performs resource allocation to the terminal, and may be at least one of a gNode B, an eNodeB, a Node B, a BS, a radio access unit, a base station controller, or a node on a network. The terminal may include a user equipment (UE), a mobile station (MS), a cellular phone, a smart phone, a computer, or a multimedia system capable of performing a communication function. However, this is merely illustrative, and the base station and the terminal are not limited to these examples. In the present disclosure, for ease of description, eNB may be used interchangeably with gNB. That is, a base station described as an eNB may represent a gNB. In the present disclosure, the term terminal may refer to various wireless communication devices as well as mobile phones, NB-IoT devices, and sensors.

[0052] In the following description, a physical channel or signal may be used interchangeably with data or a control signal. For example, a physical downlink shared channel (PDSCH) is a term referring to a physical channel through which data is transmitted, but PDSCH may also be used to refer to data. That is, in the present disclosure, the expression "transmitting a physical channel" may be interpreted as equivalent to the expression "transmitting data or a signal through a physical channel".

[0053] In the present disclosure, high-layer signaling indicates a method of transmitting a signal from a base station to a UE by using a downlink data channel of a physical layer or transmitting a signal from a UE to a base station by using an uplink data channel of a physical layer. High-layer signaling may be understood as radio resource control (RRC) signaling or medium access control (MAC) control element (CE).

[0054] Additionally, in the present disclosure, in order to determine whether a specific condition is met or fulfilled, the expression "greater than" or "less than" may be used, but this is illustrative and does not exclude the use of "greater than or equal to" or "less than or equal to". Under certain conditions, "greater than or equal to", "less than or equal to" and "greater than or equal to and less than" may be replaced by "greater than", "less than" and "greater than and greater than or equal to", respectively.

[0055] Additionally, in the present disclosure, although the embodiments are described using terms used in some communication standards (eg, 3rd Generation Partnership Project (3GPP)), these are merely illustrative for explanation. The embodiments of the present disclosure may be slightly modified and applied to other communication systems.

[0056] In the present disclosure, when a first UE is connected to a second UE through a sidelink relay in a wireless communication system, from a network perspective, the first UE, the second UE, and the sidelink relay may be in an RRC_connected state, an RRC_inactive state, an RRC_idle state, and an out-of-coverage state, and the state of the UE including the sidelink relay may be managed independently. The first UE, the second UE, and the sidelink relay may be connected to the same cell, different cells, the same base station, or different base stations.

[0057] Figure 1A is a diagram illustrating a wireless communication system according to an embodiment of the present disclosure.

[0058] Figure 1A A base station 110, UEs 130 and 140, and a sidelink relay 120 that can relay data transmission and reception between the base station and the UE are shown as some nodes using a radio channel in a wireless communication system. According to an embodiment of the present disclosure, the sidelink relay may be a U2N (UE to Network) relay. Figure 1A Only one base station is shown, but other base stations identical or similar to base station 110 may be included, and more repeaters may be included. That is, Figure 1A The configuration of the wireless communication system in is illustrative and may also include Figure 1A Other components not shown.

[0059] According to an embodiment of the present disclosure, the base station 110 may be a network infrastructure that provides radio access to the UEs 130 and 140 and the repeater 120. The base station 110 has a coverage area that is limited to a specific geographical area based on the distance at which a signal can be transmitted. In addition to "base station", the base station 110 may also be referred to as an "access point (AP)", "eNodeB (eNB)", "5G node (5th generation node)", "next generation node nodeB (gNB)", "radio point", "transmit / receive point (TRP)" or other terms with equivalent technical meanings.

[0060] According to an embodiment of the present disclosure, the repeater 120 may be used by a user or a network infrastructure, and may communicate with the base station 110 through a radio channel. The link from the base station 110 to the repeater 120 may be referred to as a downlink (DL), and the link from the repeater 120 to the base station 110 may be referred to as an uplink (UL). The base station 110 and the repeater 120 may be connected via a Uu interface. The uplink (UL) may refer to a radio link through which the repeater 120 transmits data or a control signal to the base station 110, and the downlink (DL) may refer to a radio link through which the base station 110 transmits data or a control signal to the repeater 120.

[0061] In addition, the relay 120 may communicate with the UE 130 and the UE 140 through a radio channel. The link between the relay 120 and the UE 130 and the link between the relay 120 and the UE 140 may be referred to as a side link, and the side link may also be referred to as a PC5 interface.

[0062] According to an embodiment of the present disclosure, each of the UEs 130 and 140 is a device used by a user, and may communicate with the base station 110 through a radio channel or communicate with a network through a radio channel and the relay 120 .

[0063] In the present disclosure, each of UE 130 and UE 140 may communicate with relay 120 through a radio channel. At least one of UE 130 or UE 140 may operate without user involvement. That is, at least one of UE 130 or UE 140 may be a device that performs machine type communication (MTC) and may not be carried by a user. In addition to "terminal", each of UE 130 and UE 140 may also be referred to as "user equipment (UE)", "mobile station", "subscriber station", "remote terminal", "wireless terminal", "user device", or other terms with equivalent technical meanings are used.

[0064] Figure 1B is a diagram illustrating a wireless communication system according to an embodiment of the present disclosure.

[0065] Figure 1B A wireless communication system is shown, which includes UEs 150 and 170 and a side link repeater 160 that can relay data transmission and reception between UEs, as some nodes utilizing radio channels in the wireless communication system. The side link repeater 160 can be a U2U (UE to UE) repeater. However, the wireless communication system is not limited to the above example. That is, Figure 1B The configuration of the wireless communication system in is illustrative and may also include Figure 1B Other components not shown.

[0066] According to an embodiment of the present disclosure, the relay 160 may communicate with the UE 150 and the UE 170 through a radio channel. Here, the link between the relay 160 and the UE 150 and the link between the relay 160 and the UE 170 may be referred to as a side link, and the side link may also be referred to as a PC5 interface.

[0067] According to an embodiment of the present disclosure, each of UE 150 and UE 170 may be a device used by a user, and may communicate directly through a radio channel, or may communicate with a corresponding UE through a repeater 160 and a radio channel. Here, a link between UE 150 and UE 170, a link between UE 150 and repeater 160, and a link between UE 170 and repeater 160 are referred to as side links, and the side links may also be referred to as PC5 interfaces.

[0068] At least one of UE 150 or UE 170 may operate without user involvement. That is, at least one of UE 150 or UE 170 may be a device that performs machine type communication (MTC) and may not be carried by a user. In addition to "terminal", each of UE 150 and UE 160 may also be referred to as "user equipment (UE)", "mobile station", "subscriber station", "remote terminal", "wireless terminal", "user device", or other terms with equivalent technical meanings are used.

[0069] In the following description, uplink or downlink and Uu interface may be used interchangeably, and sidelink and PC-5 may be used interchangeably.

[0070] Figure 1A and Figure 1BThe base station 110, the repeaters 120 and 160, and the UEs 130, 140, 150, and 170 shown may transmit and receive radio signals in a millimeter wave (mmWave) frequency band (e.g., 28 GHz, 30 GHz, 38 GHz, 60 GHz). In this case, in order to improve channel gain, the base station 110, the repeaters 120 and 160, and the UEs 130, 140, 150, and 170 may perform beamforming. Here, beamforming may include transmit beamforming and receive beamforming. That is, the base station 110, the repeaters 120 and 160, and the UEs 130, 140, 150, and 170 may give directionality to a transmitted signal or a received signal. To this end, the base station 110, the relays 120, 160, and the UEs 130, 140, 150, and 170 may select the service beams 112, 113, 121, 131, 141, 151, 161, and 171 through a beam search or beam management process. After the service beams 112, 113, 121, 131, 141, 151, 161, and 171 are selected, communication may be performed through resources that are in a QCL (quasi-co-location) relationship with resources from which the service beams 112, 113, 121, 131, 141, 151, 161, and 171 are transmitted.

[0071] According to an embodiment of the present disclosure, if a large-scale characteristic of a channel carrying symbols on a first antenna port can be inferred from a channel carrying symbols on a second antenna port, the first antenna port and the second antenna port can be evaluated to be in a QCL relationship. For example, the large-scale characteristic may include at least one of delay spread, Doppler spread, Doppler shift, average gain, average delay, or spatial receiver parameters.

[0072] Figure 1A and Figure 1BThe UE 130, UE 140, UE 150, and UE 170 shown may support vehicle communications. In the case of vehicle-to-vehicle communications, standardization of vehicle-to-everything (V2X) technology based on a device-to-device (D2D) communication structure has been completed in 3GPP Release 14 and Release 15 for LTE systems, and standardization of V2X technology based on 5G NR has been completed in 3GPP Release 16. NR V2X may support unicast communication, groupcast (or multicast) communication, and broadcast communication between UEs. In addition, unlike LTE V2X, which aims to transmit and receive basic safety information necessary for vehicles to travel on the road, NR V2X aims to provide more advanced services, such as vehicle platooning, advanced driving, extended sensors, and remote driving. V2X services may be divided into basic safety services and advanced services. Basic safety services may include vehicle notification (Collaborative Awareness Message (CAM) or Basic Safety Message (BSM)) services and detailed services such as left turn notification, forward collision warning, emergency vehicle approach, forward obstacle warning, and intersection movement information; and V2X information may be transmitted and received by using broadcast, unicast, or multicast transmission. Compared with basic safety services, advanced services not only enhance the quality of service (QoS) requirements, but also require methods for transmitting and receiving V2X information by using unicast and multicast in addition to broadcast, so that V2X information may be transmitted and received within a specific vehicle group or between two vehicles. Advanced services may include detailed services such as vehicle platooning, autonomous driving, remote driving, and extended sensor-based V2X services. In addition, NR V2X can provide public safety services by supporting direct communication between UEs in areas without network infrastructure.

[0073] In the following description, the side link (SL) refers to a signal transmission / reception path between UEs or a signal transmission / reception path between a UE and a repeater, and can be used interchangeably with the PC5 interface. In addition, the base station is the main agent for allocating resources to the UE and the repeater, and it can be a base station supporting V2X communication and conventional cellular communication or a base station supporting only V2X communication. That is, the base station can mean an NR base station (e.g., gNB), an LTE base station (e.g., eNB), or a roadside unit (RSU). UEs can include not only general user equipment and mobile stations, but also vehicles supporting vehicle-to-vehicle (V2V) communication, vehicles supporting vehicle-to-pedestrian (V2P) communication or pedestrian mobile phones (i.e., smart phones), vehicles supporting vehicle-to-network (V2N) communication, vehicles supporting vehicle-to-infrastructure (V2I) communication, RSUs equipped with UE functions, RSUs equipped with base station functions, and RSUs equipped with some base station functions and some UE functions.

[0074] Meanwhile, in the present disclosure, UE may refer to a vehicle supporting vehicle-to-vehicle (V2V) communication, a vehicle supporting vehicle-to-pedestrian (V2P) communication or a pedestrian's mobile phone (i.e., a smart phone), a vehicle supporting vehicle-to-network (V2N) communication, or a vehicle supporting vehicle-to-infrastructure (V2I) communication. UE may refer to a user device supporting device-to-device communication in a public safety network.

[0075] Additionally, in the present disclosure, UE may refer to a roadside unit (RSU) equipped with a UE function, an RSU equipped with a base station function, or an RSU equipped with some base station functions and some UE functions.

[0076] In the present disclosure, a repeater may refer to a vehicle supporting V2X communication or a user device supporting device-to-device communication of a public safety network. Additionally, in the present disclosure, a repeater may refer to a device equipped with UE functionality, a device equipped with base station functionality, or a device equipped with some base station functionality and some UE functionality.

[0077] Figure 2 is a diagram showing a structure of a base station in a wireless communication system according to an embodiment of the present disclosure.

[0078] Figure 2 The illustrated configuration may be understood as the configuration of the base station 110. Terms such as "unit" or "means" used herein mean a unit that processes at least one function or operation and may be implemented in hardware, software, or a combination thereof.

[0079] refer to Figure 2 , the base station 110 may include a wireless communication unit 210, a backhaul communication unit 220, a storage device 230 and / or a controller 240. However, the components of the base station 110 are not limited to those components described above. For example, the base station may include more or fewer components than those components described above. In addition, the wireless communication unit 210, the backhaul communication unit 220, the storage device 230 and the controller 240 may be implemented in the form of a single chip. In addition, the controller 240 may include one or more processors.

[0080] The wireless communication unit 210 may perform functions of transmitting and receiving signals through a radio channel. For example, the wireless communication unit 210 may perform conversion between a baseband signal and a bit stream according to the physical layer specification of the system. For example, for data transmission, the wireless communication unit 210 may generate complex symbols by encoding and modulating the transmission bit stream. In addition, for data reception, the wireless communication unit 210 may restore the reception bit stream by demodulating and decoding the baseband signal.

[0081] In addition, the wireless communication unit 210 may perform up-conversion of a baseband signal to a radio frequency (RF) band signal and transmit the converted band signal through an antenna, and may perform down-conversion of an RF band signal received through an antenna to a baseband signal. To this end, the wireless communication unit 210 may include a transmit filter, a receive filter, an amplifier, a mixer, an oscillator, a digital-to-analog converter (DAC) and / or an analog-to-digital converter (ADC). In addition, the wireless communication unit 210 may include multiple transmit and receive paths. In addition, the wireless communication unit 210 may include at least one antenna array consisting of a plurality of antenna elements.

[0082] In terms of hardware, the wireless communication unit 210 may include a digital unit and an analog unit, and the analog unit may be composed of a plurality of subunits according to operating power, operating frequency, etc. The digital unit may be implemented with at least one processor (e.g., a digital signal processor (DSP)). In the present disclosure, the expression "composed of" or "implemented with" may be replaced with the expression "comprising". For example, depending on the operating power and / or operating frequency, the analog unit may include a plurality of subunits. For example, the digital unit may include at least one processor.

[0083] The wireless communication unit 210 transmits and receives signals, as described above. Therefore, all or part of the wireless communication unit 210 may be referred to as a "transmitter", "receiver" or "transceiver". In addition, in the following description, transmission and reception performed through a radio channel are used as having the meaning of processing performed by the wireless communication unit 210 as described above.

[0084] The backhaul communication unit 220 may provide an interface for communicating with other nodes on the network. That is, the backhaul communication unit 220 may convert a bit stream to be transmitted from the base station 110 to another node (e.g., another access node, another base station, a higher node, or a core network) into a physical signal, and may convert a physical signal received from another node into a bit stream.

[0085] The storage device 230 may store data such as basic programs, applications, and configuration information for the operation of the base station 110. The storage device 230 may be configured as a volatile memory, a non-volatile memory, or a combination thereof. In addition, the storage device 230 may provide the stored data in response to a request from the controller 240.

[0086] The controller 240 may control the overall operation of the base station 110. For example, the controller 240 may transmit and receive signals through the wireless communication unit 210 or through the backhaul communication unit 220. In addition, the controller 240 may write data to the storage device 230 and read data from the storage device. In addition, the controller 240 may perform the functions of the protocol stack required by the communication standard. According to another implementation example, the protocol stack may be included in the wireless communication unit 210. To this end, the controller 240 may include at least one processor. According to an embodiment, the controller 240 may control the base station 110 to perform operations according to the embodiments described later.

[0087] Figure 3 is a diagram showing a structure of a UE in a wireless communication system according to an embodiment of the present disclosure.

[0088] Figure 3 The illustrated configuration may be understood as a configuration of UE 120. Terms such as "unit" or "means" used herein mean a unit that processes at least one function or operation and may be implemented in hardware, software, or a combination thereof.

[0089] refer to Figure 3 , UE 120 may include a communication unit 310, a storage device 320 and / or a controller 330. However, the components of UE 120 are not limited to those components described above. For example, UE 120 may include more or fewer components than those components described above. In addition, the communication unit 310, the storage device 320 and the controller 330 may be implemented in the form of a single chip. In addition, the controller 330 may include one or more processors.

[0090] The communication unit 310 can perform the function of transmitting and receiving signals through a radio channel. For example, the communication unit 310 can perform the conversion between the baseband signal and the bit stream according to the physical layer specification of the system. For example, for data transmission, the communication unit 310 can generate complex symbols by encoding and modulating the transmission bit stream. In addition, for data reception, the communication unit 310 can restore the received bit stream by demodulating and decoding the baseband signal. In addition, the communication unit 310 can perform the up-conversion conversion of the baseband signal to the RF band signal and transmit the converted band signal through the antenna, and can perform the down-conversion conversion of the RF band signal received by the antenna to the baseband signal. For example, the communication unit 310 may include a transmitting filter, a receiving filter, an amplifier, a mixer, an oscillator, a DAC and an ADC.

[0091] In addition, the communication unit 310 may include multiple transmit and receive paths. In addition, the communication unit 310 may include at least one antenna array consisting of multiple antenna elements. In terms of hardware, the communication unit 310 may be composed of digital circuits and analog circuits (e.g., radio frequency integrated circuits (RFICs)). Here, the digital circuits and analog circuits may be implemented as a single package. In addition, the communication unit 310 may include multiple RF chains. In addition, the communication unit 310 may perform beamforming.

[0092] The communication unit 310 can transmit and receive signals, as described above. Therefore, all or part of the communication unit 310 may be referred to as a "transmitter", "receiver" or "transceiver". In addition, in the following description, transmission and reception performed through a radio channel may be used as having the meaning of a process performed by the communication unit 310 as described above.

[0093] The storage device 320 may store data such as basic programs, applications, and configuration information for the operation of the UE 120. The storage device 320 may be configured as a volatile memory, a non-volatile memory, or a combination thereof. In addition, the storage device 320 may provide the stored data in response to a request from the controller 330.

[0094] The controller 330 controls the overall operation of the UE 120. For example, the controller 330 may transmit and receive signals through the communication unit 310. In addition, the controller 330 may write data to the storage device 320 and read data from the storage device. In addition, the controller 330 may perform the functions of the protocol stack required by the communication standard. To this end, the controller 330 may include at least one processor or microprocessor, or the controller 330 may be a part of the processor. In addition, the communication unit 310 and a part of the controller 330 may be referred to as a communication processor (CP). According to an embodiment, the controller 330 may control the UE 120 to perform operations according to the embodiments described later.

[0095] Figure 4 is a diagram showing a configuration of a communication unit in a wireless communication system according to an embodiment of the present disclosure.

[0096] Figure 4 Shows Figure 2 The wireless communication unit 210 or Figure 3 Specifically, Figure 4 Shown as Figure 2 The wireless communication unit 210 or Figure 3 A component for performing beamforming as a part of the communication unit 310 in FIG.

[0097] refer to Figure 4According to an embodiment of the present disclosure, the wireless communication unit 210 or the communication unit 310 may include an encoder and modulator 402, a digital beamformer 404, a plurality of transmission paths 406-1 to 406-N and / or an analog beamformer 408.

[0098] The encoder and modulator 402 may perform channel coding. For channel coding, at least one of a low density parity check (LDPC) code, a convolutional code, or a polarization code may be used. The encoder and modulator 402 may generate modulation symbols by performing constellation mapping.

[0099] The digital beamformer 404 may perform beamforming on a digital signal (e.g., a modulation symbol). To this end, the digital beamformer 404 may multiply the modulation symbol by a beamforming weight. The beamforming weight is used to change the amplitude and phase of the signal and may be referred to as a "precoding matrix" or a "precoder". The digital beamformer 404 may output the digitally beamformed modulation symbol to a plurality of transmission paths 406-1 to 406-N. Here, according to a multiple-input multiple-output (MIMO) transmission scheme, the modulation symbol may be multiplexed, or the same modulation symbol may be provided to a plurality of transmission paths 406-1 to 406-N.

[0100] Multiple transmission paths 406-1 to 406-N can convert digital beamforming digital signals into analog signals. To this end, each of the multiple transmission paths 406-1 to 406-N may include an inverse fast Fourier transform (IFFT) calculator, a cyclic prefix (CP) inserter, a DAC, and / or an up-converter. The CP inserter is used for orthogonal frequency division multiplexing (OFDM) and can be omitted when other physical layer schemes (e.g., filter bank multi-carrier (FBMC)) are applied. That is, multiple transmission paths 406-1 to 406-N can provide independent signal processing processes for multiple streams generated by digital beamforming. However, according to an embodiment, some components of the multiple transmission paths 406-1 to 406-N may be used in common.

[0101] The analog beamformer 408 may perform beamforming on the analog signal. To this end, the digital beamformer 404 may multiply the analog signal by a beamforming weight. The beamforming weight may be used to change the amplitude and phase of the signal. Specifically, the analog beamformer 408 may be configured in various ways according to the connection structure between the multiple transmission paths 406-1 to 406-N and the antenna. For example, each of the multiple transmission paths 406-1 to 406-N may be connected to an antenna array. As another example, the multiple transmission paths 406-1 to 406-N may be connected to an antenna array. As another example, the multiple transmission paths 406-1 to 406-N may be adaptively connected to an antenna array or two or more antenna arrays.

[0102] Figure 5 is a diagram showing the structure of time-frequency resources in a wireless communication system according to an embodiment of the present disclosure.

[0103] refer to Figure 5 In the radio resource region according to the embodiment of the present disclosure, the horizontal axis represents the time domain and the vertical axis represents the frequency domain. The minimum transmission unit in the time domain is an OFDM or DFT-S-OFDM symbol, and N symb OFDM or DFT-S-OFDM symbols 530 may be included in one slot 505. In the NR system, unlike a slot, the length of a subframe may be defined as 1.0 ms, and the length of a radio frame 500 may be defined as 10 ms. The minimum transmission unit in the frequency domain is a subcarrier, and the entire system transmission bandwidth may include a total of N BW subcarriers 525. N subcarriers may be variably applied according to the system. symb and N BW a specific value.

[0104] The basic unit of the time-frequency resource region is a resource element (RE) 510, which can be represented by an OFDM or DFT-S-OFDM symbol index and a subcarrier index. A resource block (RB) 515 can be defined as N in the frequency domain. RB In general, the minimum transmission unit of data is RB, and in the NR system, N symb = 14 and N RB = 12.

[0105] like Figure 5 The structure of the time-frequency resources shown can be applied to the Uu interface. Figure 5 The time-frequency resource structure shown can be similarly applied to the side link.

[0106] According to an embodiment of the present disclosure, in a case where a UE (also referred to as a remote UE or a remote terminal) is connected to another UE via a sidelink repeater (also referred to as a repeater or a relay UE) to transmit and receive data, an operating process for the UE, the sidelink repeater and the other UE to process the integrity of packets is described.

[0107] According to an embodiment of the present disclosure, a sidelink repeater may be authenticated for at least one of a specific service, a specific UE, a specific sidelink flow, a specific sidelink bearer, a specific unicast link, a specific source identifier, or a specific destination identifier, or a combination thereof. The sidelink repeater may establish a direct connection with an authenticated UE when installed.

[0108] A sidelink repeater according to an embodiment of the present disclosure may establish a sidelink direct connection with an authenticated UE upon receiving a repeater discovery message from the authenticated UE. The sidelink repeater may establish a direct sidelink connection with an authenticated UE upon receiving a repeater discovery message from the authenticated UE as a response to a repeater discovery message transmitted by the sidelink repeater itself.

[0109] When the sidelink repeater receives a PC5 direct link setup request from an authenticated UE, it may establish a sidelink direct connection with the authenticated UE. The method for the PC5 direct link setup request for relay connection by the sidelink repeater and the UE may include at least one of the following: including "connection via relay indication" in a normal PC5 direct link setup request message, separately defining a "PC5 direct link setup message for relaying", or configuring to use a normal PC5 direct link setup request message transmitted on a sidelink radio bearer (which may be represented as an SLRB) for relaying, or a combination thereof. However, the method for the PC5 direct link setup request for relay connection by the sidelink repeater and the UE is not limited to those methods described above.

[0110] Next, refer to Figure 6 , a process for establishing a sidelink unicast connection between a UE and a sidelink repeater, establishing a sidelink unicast connection between the sidelink repeater and another UE, and establishing a sidelink unicast connection between the UE and another UE through the sidelink repeater will be described when a direct connection is established between one UE and another UE through the sidelink repeater to transmit and receive signaling and data.

[0111] Figure 6 is a diagram illustrating a process for processing configuration information for relaying signaling and data in a wireless communication system according to an embodiment of the present disclosure, in which a UE and another UE communicate via a sidelink relay.

[0112] refer to Figure 6, UE1 600 may check whether it can establish a direct connection with UE2 670, and may determine to search for a side link relay 660 that can support a direct connection with UE2 670. At step 601, UE1 600 may perform a relay discovery process. At step 601, UE1 600 may utilize a process for transmitting a relay discovery request message to search for a side link relay that can support a direct connection with UE2 670 and receive a relay discovery message from the side link relay. Alternatively, at step 601, UE1 600 may utilize a process for monitoring a relay discovery message from a side link relay that can support a direct connection with UE2 670. Alternatively, at step 601, UE1 600 may utilize a process for transmitting a PC5 direct link establishment request message including an "indication of connection via a relay", the "indication of connection via a relay" indicating a search for a side link relay that can relay a connection between two UEs, wherein the transmission of the PC5 direct link establishment request message (i.e., may correspond to the transmission of the PC5 direct link establishment request message in Figure 7 The direct communication request message transmitted at step 701 of ) is used to establish a direct connection with UE2 670.

[0113] At step 602, the sidelink relay 660 may utilize a process for transmitting a relay discovery message to search for UE2 670 with which UE1 600 intends to establish a direct connection. Alternatively, at step 602, the sidelink relay 660 may utilize a process for monitoring a relay discovery request message transmitted by UE2 670 with which UE1 600 intends to establish a direct connection and transmitting the relay discovery message to UE2 670. Alternatively, at step 602, in order to search for UE2 670 with which UE1 600 intends to establish a direct connection, the sidelink relay 660 may utilize a process for transmitting a PC5 direct link establishment request message carrying information about UE2 670 with which UE1 600 intends to establish a direct connection and an “indication of connection via a relay”.

[0114] If UE1 600 determines that it can establish a direct connection with UE2 670 through the sidelink relay 660, then at step 603, it can perform a unicast connection procedure with the sidelink relay 660. If UE2 670 determines that it can establish a direct connection with UE1 600 through the sidelink relay 660, then at step 604, it can perform a unicast connection procedure with the sidelink relay 660. The sidelink unicast connection between UE1 600 and the sidelink relay 660 and the sidelink multicast connection between the sidelink relay 660 and UE2 670 can be established by performing Figure 7701 to 706 of the unicast connection setup process. However, if data transmission and reception are not required between UE1 600 and the sidelink relay 660 or between UE2 670 and the sidelink relay 660, the SLRB establishment for data transmission and reception at step 706, that is, the setting of the sidelink data radio bearer (SL-DRB) can be omitted. The specified SLRB configuration can be applied to the sidelink signaling radio bearer (SL-SRB) (SL-SRB0, SL-SRB1, SL-SRB2, SL-SRB3) for transmitting and receiving sidelink signaling at steps 603 and 604 during the unicast connection setup process (steps 605, 606).

[0115] UE1 600 and UE2 670 may establish an end-to-end unicast connection separately from the unicast connection to the sidelink relay 660. The establishment of the end-to-end unicast connection may begin with the process of UE1 600 transmitting a direct communication request message to UE2 670 through the relay transmission of the sidelink relay 660 (steps 607 and 608). However, if UE1 600 utilizes the transmission of a PC5 direct link establishment request message (i.e., may correspond to the PC5 direct link establishment request message in the Figure 7 If the process of transmitting the direct communication request message at step 701 of the side link relay 660) is used as a process for searching for a side link relay 660 that can support a connection with UE2 670, steps 607 and 608 can be performed during the relay search process (steps 601, 602) between the side link relay 660 and UE2 670.

[0116] UE1 600 and UE2 670 may perform a PC5 security procedure for handling sidelink authentication and encryption key setup (step 609) by relaying via the sidelink relay 660. At step 609, the end-to-end PC5 security procedure between UE1 600 and UE2 670 may be configured as a procedure for exchanging encryption and integrity protection algorithms and parameters to support the use of integrity protection and encryption (integrity, authentication, encryption) in a PDCP (Packet Data Convergence Protocol) protocol for end-to-end data or signaling (PC5-S signaling, PC5-RRC) of UE1 600 and UE2 670. The sidelink relay 660 may have a relay adaptation layer for relaying signaling and data of UE1 600 and UE2 670 above an RLC (Radio Link Control) layer, and does not need to have a PDCP layer, an RRC layer, and an SDAP layer for relaying purposes. Therefore, the PDCP layer, the SDAP layer, and the RRC layer may be configured only at UE1 600 and UE2 670 for data and signaling of UE1 600 and UE2 670. Therefore, the function of processing integrity protection and encryption of data and / or signaling of UE1 600 and UE2 670 may be implemented in the PDCP layer of each terminal UE (i.e., UE1 600 and UE2 670) without having to be implemented in the sidelink relay 660. Encryption and integrity protection algorithms and parameters for supporting the use of integrity protection and encryption in the PDCP protocol may be exchanged through a direct link security mode command message and a direct link security mode complete message, which are PC5-S messages for establishing end-to-end PC5-S security between UE1 600 and UE2 670, and the direct link security mode command message and the direct link security mode complete message may be transmitted and received through the relay of the sidelink relay 660. UE1 600 and UE2 670 may determine whether to apply / or not apply integrity protection to be used in the PDCP protocol and whether to apply / or not apply encryption to be used in the PDCP protocol for data or signaling according to the determination of the end-to-end PC5-S security setup process. If the security application in the PDCP protocol is activated (i.e., AS security is activated), the data and signaling transmitted and received between UE1 600 and UE2 670 may be subject to integrity protection and / or encryption in the PDCP protocol. In the case of a data bearer in which end-to-end data is transmitted between UE1 600 and UE2 670, for all data bearers, the configuration for application / non-application of integrity protection to be used in the PDCP protocol may be the same, and the configuration for application / non-application of encryption to be used in the PDCP protocol may be the same.Although not shown in the figure, the PC5-S security procedure can be used to update the integrity protection and encryption algorithms and parameters in the PDCP protocol, and if the security keys are changed, UE1 600 and UE2 670 can perform a PDCP re-establishment procedure to reconfigure the end-to-end PDCP entity.

[0117] After determining that the sidelink security process is performed normally, UE2 670 may perform a process of transmitting a direct communication acceptance message to UE1 600 through the relay of the sidelink relay 660 (steps 610 and 611). Figure 6 Although not shown in the figure, if it is necessary to exchange sidelink UE capability information between UE1 600 and UE2 670, the sidelink UE capability message can be transmitted and received between UE1 600 and UE2 (670) through the relay of the sidelink relay 660. Figure 6 Although not shown in the figure, the RRC reconfiguration message may be transmitted and received between UE1 600 and UE2 670 through relaying of the sidelink relay 660.

[0118] UE1 600 and UE2 670 can send their own data to the other UE through the relay of the side link relay 660, and can receive the data of the other UE through the relay of the side link relay 660 (step 612). The establishment of the end-to-end unicast connection can also start with the process in which UE2 670 first transmits a direct communication request message to UE1 600 through the relay of the side link relay 660.

[0119] Figure 7 is a diagram illustrating a process of processing configuration information for transmitting and receiving signaling and data in a wireless communication system allowing direct communication between UEs according to an embodiment of the present disclosure.

[0120] refer to Figure 7 UE1 700 and UE2 750 are UEs that can establish a direct connection through a side link interface and transmit and receive data and signaling through the direct connection. At step 701, UE1 700 can transmit a direct communication request message to establish a direct connection with UE2 750.

[0121] When UE2 750 receives the direct communication request message at step 701, at step 702, UE2 750 may perform a PC5 security setup procedure (such as side link authentication and encryption key configuration) with UE1 700 for establishing a direct connection with UE1 700. After determining that the side link authentication, encryption key configuration, etc. for establishing a direct connection between UE1 700 and UE2 750 have been performed normally, at step 703, UE2 750 may transmit a direct communication acceptance message to UE1 700.

[0122] UE1 700 and UE2 750 may perform a subsequent procedure for establishing a direct connection, and at step 706, signaling for exchanging sidelink UE capability information may be exchanged between the RRC layers of UE1 700 and UE2 750. At step 706, signaling for exchanging configuration information about a sidelink radio bearer (SLRB) for data transmission and reception may be exchanged between the RRC layers of UE1 700 and UE2 750.

[0123] The sidelink signaling radio bearers corresponding to the signaling transmitted and received between UE1 700 and UE2 750 at steps 701 to 706 may correspond to SL-SRB0, SL-SRB1, SL-SRB2, and SL-SRB3, and the configuration information of SL-SRB0, SL-SRB1, SL-SRB2, and SL-SRB3 may be stored in UE1 700 and UE2 750 as specified configurations.

[0124] There may be three examples of a method for UE1 700 and UE2 750 to obtain configuration information of a sidelink data radio bearer (SL-DRB) corresponding to the data at step 706 , as shown in Table 1.

[0125] [Table 1]

[0126] If UE1 700 or UE2 750 is a transmitting UE, UE1 700 or UE2 750 may obtain configuration information of a sidelink data radio bearer for a QoS flow corresponding to data to be transmitted by utilizing one of the three methods of Table 1, and at step 706, SLRB configuration information of the QoS flow may be transmitted to UE2 750 or UE1 700 as a receiving UE by RRC layer signaling. SLRB configuration information (limited to only RX SLRB configuration information) of a QoS flow to be applied by the receiving UE to the received data may be determined by the receiving UE itself. UE1 700 and UE2 750 may transmit and receive data at step 707 by applying the SLRB configuration information configured for the data at step 706. In the case where one UE establishes a connection with another UE through a sidelink repeater, when a sidelink unicast connection is established between the UE and the sidelink repeater, a specified SLRB configuration may be applied to the signaling radio bearers (SL-SRB0, SL-SRB1, SL-SRB2, SL-SRB3) between the UE and the sidelink repeater. In the case of processing integrity protection and encryption set for data and signaling between UE1 and UE2 according to various embodiments of the present disclosure, integrity protection and encryption may be handled for received data packets or signaling packets in the PDCP layer of UE1 or UE2 corresponding to the receiving UE. That is, this may include performing integrity protection and encryption processing on a PDCP PDU corresponding to a data packet or a PDCP PDU corresponding to a signaling packet. The receiving UE may determine whether integrity protection is successful or encryption is successful for the received data packet or signaling packet. Next, referring to Figure 8 , a process for processing integrity protection of a PDCP PDU corresponding to a signaling packet associated with a SL-SRB1 between a transmitting UE and a receiving UE transmitted through a sidelink relay will be described. The signaling packet corresponding to the SL-SRB1 may include PC5-S signaling carrying information about integrity protection and encryption between the transmitting UE and the receiving UE.

[0127] Figure 8 is a diagram illustrating a process for handling integrity protection of signaling packets received through a sidelink repeater according to an embodiment of the present disclosure.

[0128] refer to Figure 8, UE1 800 and UE2 870 can transmit and receive data and signaling through the relay of the sidelink repeater 860. At step 801, UE1 800 can transmit PC5-S signaling corresponding to SL-SRB1 to UE2 870 through the sidelink repeater 860. If integrity protection is set for the PC5-S signaling corresponding to SL-SRB1, UE1 800 can apply integrity protection to the PC5-S signal at step 801 and transmit it. Here, integrity protection handling of the PDCP PDU including the PC5-S signaling can be performed by the transmitting PDCP entity of UE1 800. If integrity protection is not set for the PC5-S signaling corresponding to SL-SRB1, UE1 800 can transmit the PC5-S signal at step 801 without applying integrity protection. Figure 8 In the disclosure of , it is assumed that integrity protection is set for PC5-S signaling corresponding to SL-SRB1. UE2 870 may know that integrity protection is applied to PC5-S signaling corresponding to SL-SRB1 received through relay forwarding of the sidelink relay 860, and determine whether the integrity protection is successful at step 802. The operation of step 802 is processed in the receiving PDCP entity of UE2 870, and UE2 870 (i.e., the receiving PDCP entity of UE2 870) may determine whether integrity protection is successful at the PDCP PDU including the PC5-S signaling. If UE2 870 determines at step 802 that integrity protection of the PC5-S signaling corresponding to SL-SRB1 has failed, it may transmit information (e.g., an integrity check failure indication) notifying the failure of integrity protection of the corresponding packet to its upper layer (RRC layer, ProSe layer, PC5-S layer, or V2X layer) at step 803. UE2 870 may delete the packet for which integrity protection is determined to have failed, and transmit a direct link security mode reject message corresponding to PC5-S signaling at step 804 to notify UE1 800 of the integrity protection failure. The direct link security mode reject message at step 804 may correspond to PC5-S signaling of a higher layer (i.e., a ProSe layer or PC5-S layer or V2X layer responsible for integrity protection and encryption processing) of UE2 870. At step 805, UE1 800 and UE2 870 may process integrity protection settings again through authentication and encryption procedures for end-to-end connection between UE1 800 and UE2 870.

[0129] exist Figure 8In the disclosure of , after receiving PC5-S signaling notifying integrity protection failure of PC5-S signaling corresponding to PC5-SRB1 from UE2 870, UE1 800 may transmit an indication notifying PDCP integrity protection failure to its lower layer (e.g., RRC layer), and the lower layer of UE1 800 may trigger a PDCP re-establishment procedure of UE2 870. If the upper layer of UE2 870 determines that integrity protection failure of PC5-S signaling corresponding to PC5-SRB1 has occurred, it may transmit an indication notifying PDCP integrity protection failure to its lower layer (e.g., RRC layer), and the lower layer of UE2 870 (e.g., RRC layer) may trigger a PDCP re-establishment procedure of UE1 800. Operations that may be performed when indicating PDCP integrity protection failure to the lower layers (e.g., RRC layer) of UE1 800 and UE2 870 may include the following operations.

[0130] [Table 2]

[0131] Next, refer to Fig. 9 and Fig.10 , a process for processing integrity protection of signaling packets corresponding to SL-SRB2 and SL-SRB3 between a transmitting UE and a receiving UE transmitted through a relay of a sidelink repeater will be described. The signaling packets corresponding to SL-SRB2 and SL-SRB3 may reflect the integrity protection and encryption settings between the transmitting UE and the receiving UE, and may include PC5-S signaling and PC5-RRC messages for which integrity protection or / and encryption may be set. That is, the transmitting UE and the receiving UE may process integrity protection or / and encryption of the PDCP PDU corresponding to the SL-SRB2 signaling packet or the SL-SRB3 signaling packet. Fig. 9 is a diagram illustrating a process of handling integrity protection of a signaling packet received via a side link repeater according to an embodiment of the present disclosure.

[0132] refer to Fig. 9 , UE1 900 and UE2 970 may transmit and receive data and signaling through the relay of the sidelink relay 960. At step 901, UE1 900 may transmit a PC5 RRC message corresponding to SL-SRB3 to UE2 970 through the sidelink relay 960. Fig. 9The disclosure may also be applied to a PDCP PDU including PC5-S signaling corresponding to SL-SRB2. If UE1 900 and UE2 970 are configured to set integrity protection for a PC5 RRC message corresponding to SL-SRB3, UE1 900 may apply integrity protection to the PDCP PDU of the PC5 RRC message and transmit it at step 901. The operation of step 901 may be performed by a transmitting PDCP entity of UE1 900. If it is configured not to set integrity protection for a PC5RRC message corresponding to SL-SRB3, UE1 900 may transmit a PC5 RRC message at step 901 without applying integrity protection. Fig. 9 In the disclosure, it is assumed that integrity protection is set for the PC5 RRC message corresponding to SL-SRB3. UE2 970 may know that integrity protection is applied to the PC5 RRC message corresponding to SL-SRB3 received through the relay of the sidelink relay 960, and may determine whether the integrity protection is successful at step 902. The operation of step 902 may be processed by the receiving PDCP entity of UE2970. If UE2 970 determines at step 902 that the integrity protection of the PC5 RRC message corresponding to SL-SRB3 fails, it may transmit information notifying the integrity protection failure of the corresponding packet to its upper layer (RRC layer, ProSe layer, PC5-S layer, or V2X layer) at step 903. UE2 970 may delete the packet for which integrity protection is determined to have failed, and transmit PC5-S signaling to UE1 900 at step 904 to notify the integrity protection failure. The PC5-S signaling at step 904 may be a direct link security mode reject message, or correspond to PC5-S signaling separately defined for the purpose of notifying integrity protection failure regarding PC5-S signaling corresponding to SL-SRB2 or PC5 RRC message corresponding to SL-SRB3. The PC5-S signaling at step 904 may correspond to PC5-S signaling of a higher layer (i.e., a ProSe layer, a PC5-S layer, or a V2X layer responsible for integrity protection and encryption processing) of UE2 970. At step 905, upon receiving PC5-S signaling indicating integrity protection failure of PC5-S signaling corresponding to SL-SRB2 received at step 904 or PC5 RRC message corresponding to SL-SRB3, UE1 900 may recognize PDCP integrity protection failure.

[0133] Due to the failure of integrity protection of the PDCP PDU, the upper layer of UE1 900 can instruct its RRC layer or PDCP layer to trigger PDCP entity reestablishment (step 906). If necessary, due to the failure of PDCP integrity protection, the upper layer of UE2 970 can instruct its RRC layer or PDCP layer to trigger PDCP entity reestablishment (step 907). UE1 900 can suspend packet transmission corresponding to all SL-SRBs and SL-DRBs of UE2 970. UE1 900 can trigger PDCP entity reestablishment at step 906. UE2 970 can trigger PDCP entity reestablishment at step 907. Regarding the connection with UE2 970, UE1 900 can perform MAC entity reset, RLC entity reestablishment, or RLC entity release with the sidelink relay 960. Regarding the connection with UE1 900, UE2 970 can perform MAC entity reset, RLC entity reestablishment, or RLC entity release with the sidelink relay 960. Here, UE1 900 and UE2 970 may transmit a PC5 RRC message (e.g., a notification message) to the sidelink relay 960 to notify the PDCP reestablishment of the other party's UE due to the integrity protection failure, and notify the MAC entity reset, RLC entity reestablishment, or RLC entity release. The notification message may also be used by the sidelink relay 960 to release the sidelink relay configuration information of UE1 900 and UE2 970.

[0134] For example, in Fig. 9 In the disclosure of , after receiving PC5-S signaling notifying about integrity protection failure of PC5 RRC message corresponding to PC5-SRB3 from UE2 970, UE1 900 may transmit an indication notifying PDCP integrity protection failure to its lower layer (e.g., RRC layer), and the lower layer of UE1 900 may trigger a PDCP re-establishment procedure of UE2 970. If the upper layer of UE2 970 recognizes that integrity protection failure of PC5 RRC message corresponding to PC5-SRB3 has occurred, it may transmit an indication notifying PDCP integrity protection failure to its lower layer (e.g., RRC layer), and the lower layer of UE2 970 (e.g., RRC layer) may trigger a PDCP re-establishment procedure of UE1 900. Operations that may be performed when indicating PDCP integrity protection failure to the lower layers (e.g., RRC layer) of UE1 900 and UE2 970 may include the following operations.

[0135] [Table 3]

[0136] UE1 900 and UE2 970 may perform authentication and encryption procedures at a higher layer (eg, ProSe layer, PC5-S layer, or V2X layer) for end-to-end connection during the PDCP re-establishment procedure at step 908 , and may process integrity protection configuration again. Fig.10 is a diagram illustrating a process for handling integrity protection of signaling packets received through a sidelink repeater according to an embodiment of the present disclosure.

[0137] refer to Fig.10 At step 1001, UE1 1000 and UE2 1070 may transmit and receive data and signaling through the relay of the sidelink relay 1060. At step 1002, UE1 1000 may transmit a PC5 RRC message corresponding to SL-SRB3 to UE2 1070 through the sidelink relay 1060. Fig.10 The disclosure may also be applied to a PDCP PDU including PC5-S signaling corresponding to SL-SRB2. If UE1 1000 and UE2 1070 are configured to set PDCP integrity protection for a PC5RRC message corresponding to SL-SRB3, UE1 1000 may apply integrity protection to the PDCP PDU of the PC5 RRC message and transmit it at step 1002. The operation of step 1002 may be performed by a transmitting PDCP entity of UE1 1000. If it is configured not to set integrity protection for a PC5 RRC message corresponding to SL-SRB3, UE1 1000 may transmit the PC5 RRC message at step 1002 without applying integrity protection. Fig.10In the disclosure of , it is assumed that integrity protection is set for the PC5 RRC message corresponding to SL-SRB3. UE2 1070 may know that integrity protection is applied to the PC5 RRC message corresponding to SL-SRB3 received through the relay of the sidelink relay 1060, and may determine whether the integrity protection is successful at step 1003. The operation of step 1003 may be processed by the receiving PDCP entity of UE2 1070. After determining at step 1003 that the integrity protection of the PC5 RRC message corresponding to SL-SRB3 fails, UE2 1070 may determine at step 1004 that a failure has occurred in the sidelink radio link with UE1 1000. At step 1005, UE2 1070 may perform a process for handling a sidelink radio link failure (RLF) caused by a PDCP integrity protection failure. The process performed by UE2 1070 when a sidelink radio link failure occurs due to a PDCP integrity protection failure may include, for example, the following steps. At step 1006, UE2 1070 may perform a process of releasing the PC5 RRC connection with UE1 1000. At step 1007, UE1 1000 may perform a process of releasing the PC5 unicast link with UE2 1070. At step 1008, UE2 1070 may transmit a PC5 RRC message (e.g., a notification message) to the sidelink relay 1060 that relays data and signaling with UE1 1000 to notify UE1 1000 of the PDCP integrity protection failure. The process for handling the sidelink radio link failure caused by the PDCP PDU integrity protection failure performed between UE2 1070, UE1 1000, and the sidelink relay 1060 (including the above steps 1006, 1007, and 1008) is as follows.

[0138] [Table 4]

[0139] UE1 1000 and UE2 1070 may perform an end-to-end PC5 direct link release procedure, perform an end-to-end PC5 direct link establishment procedure, perform an authentication and encryption procedure during the PC5 direct link establishment procedure for end-to-end connection, and process integrity protection configuration again. Figure 8 , Fig. 9 and Fig.10 The transmitting PDCP entity reestablishment process performed by UE1 and UE2 in the disclosure may include the following contents.

[0140] [Table 5]

[0141] exist Figure 8 , Fig. 9 and Fig.10 The receiving PDCP entity reestablishment process performed by UE1 and UE2 in the disclosure may include the following contents.

[0142] [Table 6]

[0143] The method according to the embodiment described in the claims or the specification of the present disclosure may be implemented in the form of hardware, software or a combination thereof. When implemented with software, a computer-readable storage medium storing one or more programs (software modules) may be provided. One or more programs stored in the computer-readable storage medium may be configured to be executable by one or more processors of an electronic device. One or more programs may include instructions that enable an electronic device to execute the method according to the embodiment described in the claims or the specification of the present disclosure. Such a program (software module, software) may be stored in a random access memory, a non-volatile memory such as a flash memory, a read-only memory (ROM), an electrically erasable programmable ROM (EEPROM), a magnetic disk storage device, a compact disc-ROM (CD-ROM), a digital versatile disc (DVD) or other types of optical storage devices and / or a tape cassette. Alternatively, such a program may be stored in a memory including a combination of some or all memories. In addition, multiple component memories may be included.

[0144] In addition, such a program may be stored in an attachable storage device that can be accessed through a communication network such as the Internet, an intranet, a local area network (LAN), a wide LAN (WLAN), or a storage area network (SAN), or through a combination thereof. Such a storage device can access the device that performs the embodiments of the present disclosure through an external port. In addition, an independent storage device on a communication network can access the device that performs the embodiments of the present disclosure.

[0145] In the embodiments of the present disclosure described above, the elements included in the present disclosure are expressed in singular or plural form according to the specific embodiment presented. However, for ease of description, singular or plural expression is appropriately selected according to the current situation, and the present disclosure is not limited to a single element or multiple elements. Those elements described in plural form can also be configured as a single element, and those elements described in singular form can be configured as multiple elements.

[0146] At the same time, although the detailed description of the present disclosure has described specific embodiments, it is apparent that various modifications are possible without departing from the scope of the present disclosure. Therefore, the scope of the present disclosure should not be limited to those described embodiments, but should be determined by the scope of the claims described below and their equivalents.

Claims

1. A method performed by a first user equipment UE in a wireless communication system, the method include: Detection of Packet Data Convergence Protocol PDCP integrity verification failure; detecting a sidelink radio link failure RLF caused by the PDCP integrity verification failure; releasing a sidelink connection with a second UE in response to the sidelink radio link failing; as well as A message notifying the sidelink radio link failure due to the PDCP integrity verification failure is transmitted to a relay UE.

2. The method according to claim 1, in, The second UE transmits a message informing the sidelink radio link failure due to the PDCP integrity verification failure to the relay UE.

3. The method according to claim 1, in, Releasing the sidelink connection with the second UE includes: Release at least one of: a data radio bearer DRB for the second UE, a signaling radio bearer SRB for the second UE, configuration information configured for transmitting and receiving data and signaling for the second UE, or a PC5 radio resource control RRC connection with the second UE.

4. The method according to claim 1, in, The relay UE performs a process for releasing the sidelink relay configuration information of the first UE and the second UE, resetting the sidelink medium access control MAC, and releasing or reestablishing the sidelink radio link control RLC based on the message.

5. A method performed by a second user equipment UE in a wireless communication system, the method include: In response to a sidelink radio link failure RLF at the first UE, releasing the sidelink connection with the first UE; as well as transmitting a message notifying the side link radio link failure due to Packet Data Convergence Protocol (PDCP) integrity verification failure to the relay UE, The PDCP integrity verification failure is detected by the first UE, and the sidelink radio link failure is detected due to the PDCP integrity verification failure.

6. The method according to claim 5, in, The first UE transmits the message notifying the sidelink radio link failure due to the PDCP integrity verification failure to the relay UE.

7. The method according to claim 5, in, Releasing the sidelink connection with the first UE includes: Release at least one of: a data radio bearer DRB for the first UE, a signaling radio bearer SRB for the first UE, configuration information configured for transmitting and receiving data and signaling for the first UE, or a PC5 radio resource control RRC connection with the first UE.

8. The method according to claim 5, in, The relay UE performs a process for releasing the sidelink relay configuration information of the first UE and the second UE, resetting the sidelink medium access control MAC, and releasing or reestablishing the sidelink radio link control RLC based on the message.

9. A first user equipment UE in a wireless communication system, include: a transceiver capable of transmitting and receiving at least one signal; as well as A controller connected to the transceiver, Wherein, the controller is configured as: Detection of Packet Data Convergence Protocol PDCP integrity verification failure; detecting a sidelink radio link failure RLF caused by the PDCP integrity verification failure; releasing a sidelink connection with a second UE in response to the sidelink radio link failing; as well as A message notifying the sidelink radio link failure due to the PDCP integrity verification failure is transmitted to a relay UE.

10. The first UE according to claim 9, in, The second UE transmits the message notifying the sidelink radio link failure due to the PDCP integrity verification failure to the relay UE.

11. The first UE according to claim 9, in, The controller is configured to: At least one of the following is released: a data radio bearer DRB for the second UE, a signaling radio bearer SRB for the second UE, configuration information configured for transmitting and receiving data and signaling for the second UE, or a PC5 radio resource control RRC connection.

12. The first UE according to claim 9, in, The relay UE performs a process for releasing the sidelink relay configuration information of the first UE and the second UE, resetting the sidelink medium access control MAC, and releasing or reestablishing the sidelink radio link control RLC based on the message.

13. A second user equipment UE in a wireless communication system, include: a transceiver capable of transmitting and receiving at least one signal; as well as A controller connected to the transceiver, Wherein, the controller is configured as: In response to a sidelink radio link failure RLF at a first UE, releasing a sidelink connection with the first UE; and transmitting a message notifying the side link radio link failure due to Packet Data Convergence Protocol (PDCP) integrity verification failure to the relay UE, The PDCP integrity verification failure is detected by the first UE, and the sidelink radio link failure is detected due to the PDCP integrity verification failure.

14. The second UE according to claim 13, in, The controller is configured to: Release at least one of: a data radio bearer DRB for the first UE, a signaling radio bearer SRB for the first UE, configuration information configured for transmitting and receiving data and signaling for the first UE, or a PC5 radio resource control RRC connection with the first UE.

15. The second UE according to claim 13, in, The relay UE performs a process for releasing the sidelink relay configuration information of the first UE and the second UE, resetting the sidelink medium access control MAC, and releasing or reestablishing the sidelink radio link control RLC based on the message.

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