Method and apparatus for direct communication between terminals

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting higher data transmission rates. The present disclosure relates to a method and apparatus for directly transmitting user data between terminals without passing through a network.

Description

Method and device for direct communication between terminals

[0001] The present disclosure relates to a wireless communication system, and more particularly, to a method and device for transmitting user data directly between terminals without going through a network.

[0002] 5G mobile communication technology defines a wide frequency band to enable fast transmission speeds and new services, and can be implemented not only in the sub-6GHz band, such as 3.5 gigahertz (3.5GHz), but also in the ultra-high frequency band (Above 6GHz), also called millimeter wave (mmWave), such as 28GHz and 39GHz. In addition, for 6G mobile communication technology, which is called the system after 5G communication (Beyond 5G), implementation in the terahertz (THz) band (for example, 3 THz band at 95GHz) is being considered to achieve a transmission speed that is 50 times faster than 5G mobile communication technology and ultra-low latency that is reduced to one-tenth.

[0003] In the early stages of 5G mobile communication technology, the goal is to support services and satisfy performance requirements for ultra-wideband services (eMBB: enhanced Mobile Broadband), ultra-reliable / ultra-low-latency communications (URLLC: Ultra-Reliable Low-Latency Communications), and massive Machine-Type Communications (mMTC). These include beamforming and massive MIMO (Massive MIMO) to alleviate path loss of radio waves in ultra-high frequency bands and increase the transmission distance of radio waves, support for various numerologies (such as operation of multiple sub-carrier intervals) and dynamic operation of slot formats for efficient use of ultra-high frequency resources, initial access technology to support multi-beam transmission and wideband, definition and operation of BWP (Bidth Part), new channel coding methods such as LDPC (Low Density Parity Check) codes for large-capacity data transmission and polar codes for reliable transmission of control information, L2 pre-processing, and specific services. Standardization has been progressed for network slicing, which provides specialized, dedicated networks.

[0004] Currently, discussions are underway to improve and enhance the initial 5G mobile communication technology in consideration of the services that 5G mobile communication technology was intended to support, and physical layer standardization is in progress for technologies such as V2X (Vehicle-to-Everything) to help autonomous vehicles make driving decisions and increase user convenience based on their own location and status information transmitted by vehicles, NR-U (New Radio Unlicensed) for the purpose of system operation that complies with various regulatory requirements in unlicensed bands, NR terminal low power consumption technology (UE Power Saving), Non-Terrestrial Network (NTN), which is direct terminal-satellite communication to secure coverage in areas where communication with terrestrial networks is impossible, and Positioning.

[0005] In addition, standardization of wireless interface architecture / protocols is in progress for technologies such as intelligent factories (IIoT: Industrial Internet of Things) to support new services through linkage and convergence with other industries, Integrated Access and Backhaul (IAB) to provide nodes for expanding network service areas by integrating wireless backhaul links and access links, Mobility Enhancement technology including Conditional Handover and Dual Active Protocol Stack (DAPS) handover, and 2-step random access (2-step RACH for NR) to simplify random access procedures. Standardization is also in progress for system architecture / services such as 5G baseline architecture (e.g., Service-based Architecture: SBA, Service-based Interface: SBI) for grafting Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) technologies, and Mobile Edge Computing (MEC) that provides services based on the location of the terminal.

[0006] When such 5G mobile communication systems are commercialized, an explosive increase in connected devices will be connected to the communication network, which will require enhanced functions and performance of 5G mobile communication systems and integrated operation of connected devices. To this end, new research will be conducted on improving 5G performance and reducing complexity, supporting AI services, supporting metaverse services, and drone communications by utilizing eXtended Reality (XR), Artificial Intelligence (AI), and Machine Learning (ML) to efficiently support Augmented Reality (AR), Virtual Reality (VR), and Mixed Reality (MR).

[0007] In addition, the development of these 5G mobile communication systems includes new waveforms to ensure coverage in the terahertz band of 6G mobile communication technology, multi-antenna transmission technologies such as Full Dimensional MIMO (FD-MIMO), array antennas, and large scale antennas, metamaterial-based lenses and antennas to improve the coverage of terahertz band signals, high-dimensional spatial multiplexing technology using Orbital Angular Momentum (OAM), Reconfigurable Intelligent Surface (RIS) technology, as well as full duplex technology to improve the frequency efficiency and system network of 6G mobile communication technology, satellite, and AI (Artificial Intelligence) from the design stage and internalize end-to-end AI support functions to realize system optimization, and ultra-high-performance communication and computing resources to realize services with complexity that exceeds the limits of terminal computing capabilities. It could serve as a basis for the development of next-generation distributed computing technologies.

[0008] The present invention aims to provide a method and device capable of directly transmitting user data between terminals in a wireless communication system.

[0009] The technical problems to be achieved in the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by a person having ordinary skill in the technical field to which the present invention belongs from the description below.

[0010] In order to solve the above problem, a method performed by a proximity service relay terminal of a wireless communication system according to an embodiment of the present invention may include the steps of: receiving, from a source proximity service terminal, a first direct communication request message including identification information capable of identifying a target proximity service terminal corresponding to the source proximity service terminal; transmitting a second direct communication request message to the target proximity service terminal identified based on the identification information; receiving a first direct communication response message from the target proximity service terminal; and transmitting a second direct communication response message to the source proximity service terminal.

[0011] According to an embodiment, the method may further include the steps of: receiving a first terminal-to-terminal relay discovery request message from the source proximity service terminal; transmitting a second terminal-to-terminal relay discovery request message; receiving a first terminal-to-terminal relay discovery response message from the target proximity service terminal; and transmitting a second terminal-to-terminal relay discovery response message to the source proximity service terminal, the second terminal-to-terminal relay discovery response message including identification information capable of identifying the target proximity service terminal corresponding to the source proximity service terminal.

[0012] According to an embodiment, the second direct communication request message may be transmitted to the target proximity service terminal by unicast.

[0013] According to an embodiment, the method may further include a step of transmitting the third direct communication request message by broadcast when the proximity service relay terminal cannot identify the target proximity service terminal corresponding to the source proximity service terminal based on the identification information.

[0014] In addition, a method performed by a source proximity service terminal of a wireless communication system according to an embodiment of the present invention for solving the above-described problem may include the steps of: transmitting, to a proximity service relay terminal, a direct communication request message including identification information capable of identifying a target proximity service terminal corresponding to the source proximity service terminal; receiving, from the proximity service relay terminal, a direct communication response message based on the direct communication request transmitted to the target proximity service terminal identified based on the identification information; and performing communication with the target proximity service terminal via the proximity service relay terminal. According to an embodiment, the method may further include the steps of: transmitting, to the proximity service relay terminal, a terminal-to-terminal relay discovery request message; and receiving, from the proximity service relay terminal, a terminal-to-terminal relay discovery response message including the identification information capable of identifying the target proximity service terminal corresponding to the source proximity service terminal.

[0015] According to an embodiment, a request message according to the direct communication request message may be transmitted unicast from the proximity service relay terminal to the target proximity service terminal.

[0016] In an embodiment, when the proximity service relay terminal cannot identify the target proximity service terminal corresponding to the source proximity service terminal based on the identification information, a request message according to the direct communication request message may be transmitted as a broadcast by the proximity service relay terminal.

[0017] In addition, in order to solve the above-described problem, according to an embodiment of the present invention, a proximity service relay terminal of a wireless communication system may include a transceiver; and a control unit connected to the transceiver, configured to receive, from a source proximity service terminal, a first direct communication request message including identification information capable of identifying a target proximity service terminal corresponding to the source proximity service terminal, transmit a second direct communication request message to the target proximity service terminal identified based on the identification information, receive a first direct communication response message from the target proximity service terminal, and transmit a second direct communication response message to the source proximity service terminal.

[0018] In addition, a source proximity service terminal of a wireless communication system according to an embodiment of the present invention for solving the above-described problem may include a transceiver; and a control unit connected to the transceiver and configured to transmit, to a proximity service relay terminal, a direct communication request message including identification information capable of identifying a target proximity service terminal corresponding to the source proximity service terminal, and receive a direct communication response message from the proximity service relay terminal based on the direct communication request transmitted to the target proximity service terminal identified based on the identification information, and perform communication with the target proximity service terminal through the proximity service relay terminal.

[0019] One embodiment of the present invention provides a device and method capable of effectively providing a service in a wireless communication system.

[0020] One embodiment of the present invention can provide a method and device capable of directly transmitting user data between terminals in a wireless communication system.

[0021] The effects that can be obtained from the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by a person having ordinary skill in the art to which the present disclosure pertains from the description below.

[0022] FIG. 1 is a diagram showing an example of a configuration of a wireless communication system according to an embodiment of the present disclosure, and FIG. 1 exemplifies the configuration of a 5G system.

[0023] FIG. 2 illustrates a 5G ProSe (proximity based services) UE-to-UE Relay structure according to one embodiment of the present disclosure.

[0024] FIG. 3 illustrates a 5G ProSe UE-to-Network Relay structure according to one embodiment of the present disclosure.

[0025] FIG. 4 illustrates a model A scheme for 5G ProSe Relay discovery according to one embodiment of the present disclosure.

[0026] FIG. 5 illustrates a 5G ProSe Relay discovery model B scheme according to one embodiment of the present disclosure.

[0027] FIG. 6 illustrates a procedure of a 5G ProSe UE-to-UE Relay Discovery Model B scheme according to an embodiment of the present disclosure.

[0028] FIG. 7 illustrates a procedure for establishing a Layer-2 link for PC5 communication using a 5G ProSe Layer-3 UE-to-UE Relay according to an embodiment of the present disclosure.

[0029] FIG. 8 illustrates another procedure for establishing a Layer-2 link for PC5 communication using a 5G ProSe Layer-3 UE-to-UE Relay according to an embodiment of the present disclosure.

[0030] FIG. 9 is a diagram showing the configuration of a terminal according to an embodiment of the present disclosure.

[0031] FIG. 10 is a diagram illustrating a configuration of a base station or network entity according to an embodiment of the present disclosure.

[0032] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. It should be noted that, where possible, identical components are represented by identical reference numerals throughout the attached drawings. Furthermore, detailed descriptions of well-known functions and configurations that may obscure the gist of the present invention will be omitted.

[0033] In describing the embodiments herein, descriptions of technical details that are well known in the technical field to which the present disclosure pertains and are not directly related to the present invention will be omitted. This is to avoid obscuring the gist of the present disclosure by omitting unnecessary explanations and to convey the gist more clearly.

[0034] For the same reason, some components in the attached drawings are exaggerated, omitted, or schematically depicted. Furthermore, the dimensions of each component do not entirely reflect its actual size. Identical or corresponding components in each drawing are assigned the same reference numbers.

[0035] The advantages and features of the present disclosure, and the methods for achieving them, will become clearer with reference to the embodiments described in detail below together with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below and may be implemented in various different forms. The embodiments are provided only to ensure that the disclosure of the present disclosure is complete and to fully inform those skilled in the art of the scope of the disclosure, and the present disclosure is defined only by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

[0036] Furthermore, when describing the present disclosure, detailed descriptions of related functions or configurations will be omitted if they are deemed to unnecessarily obscure the gist of the present disclosure. Furthermore, the terms described below are defined based on the functions of the present disclosure and may vary depending on the intent or custom of the user or operator. Therefore, their definitions should be based on the content throughout this specification.

[0037] Hereinafter, the base station is an entity that performs resource allocation of a terminal, and may be at least one of a gNode B (gNB), an eNode B (eNB), a Node B, a BS (base station), a wireless access unit, a base station controller, or a node on a network. The terminal may include a UE (user equipment), an MS (mobile station), a cellular phone, a smartphone, a computer, or a multimedia system capable of performing a communication function. In the present disclosure, the downlink (DL) refers to a wireless transmission path of a signal transmitted from a base station to a terminal, and the uplink (UL) refers to a wireless transmission path of a signal transmitted from a terminal to a base station. In addition, although LTE, LTE-A, or 5G systems may be described below as examples, embodiments of the present disclosure may also be applied to other communication systems having similar technical backgrounds or channel types. For example, this may include the fifth-generation mobile communication technology (5G, new radio, NR) developed after LTE-A. The term "5G" below may also encompass existing LTE, LTE-A, and other similar services. Furthermore, the present disclosure may be applied to other communication systems with some modifications, as determined by a person with skilled technical knowledge, without significantly departing from the scope of the present disclosure.

[0038] At this time, it will be understood that each block of the processing flow diagrams and combinations of the flow diagrams can be performed by computer program instructions. These computer program instructions can be installed in a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing equipment, so that the instructions executed by the processor of the computer or other programmable data processing equipment create a means for performing the functions described in the flow diagram block(s). These computer program instructions can also be stored in a computer-available or computer-readable memory that can direct a computer or other programmable data processing equipment to implement the functions in a specific manner, so that the instructions stored in the computer-available or computer-readable memory can also produce a manufactured item that includes an instruction means for performing the functions described in the flow diagram block(s). Since the computer program instructions may be installed on a computer or other programmable data processing device, a series of operational steps may be performed on the computer or other programmable data processing device to create a computer-executable process, and the instructions that cause the computer or other programmable data processing device to perform the steps for performing the functions described in the flowchart block(s) may also provide steps for performing the functions described in the flowchart block(s).

[0039] Additionally, each block may represent a module, segment, or portion of code that contains one or more executable instructions for performing a specific logical function(s). It should also be noted that in some alternative implementation examples, the functions described in the blocks may occur out of order. For example, two blocks depicted in succession may actually be executed substantially concurrently, or the blocks may sometimes be executed in reverse order, depending on their respective functions.

[0040] Here, the term '~ unit' used in the present embodiment means a software or hardware component such as an FPGA or ASIC, and the '~ unit' performs certain roles. However, the '~ unit' is not limited to software or hardware. The '~ unit' may be configured to be on an addressable storage medium and may be configured to regenerate one or more processors. Thus, as an example, the '~ unit' includes components such as software components, object-oriented software components, class components, and task components, processes, functions, properties, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functions provided within the components and '~ units' may be combined into a smaller number of components and '~ units' or further separated into additional components and '~ units'. In addition, the components and '~ units' may be implemented to regenerate one or more CPUs within a device or a secure multimedia card. Additionally, in the embodiment, '~bu' may include one or more processors.

[0041] Wireless communication systems are evolving from providing voice-oriented services in the early days to broadband wireless communication systems that provide high-speed, high-quality packet data services, such as communication standards such as 3GPP's HSPA (High Speed ​​Packet Access), LTE (Long Term Evolution or E-UTRA (Evolved Universal Terrestrial Radio Access)), LTE-Advanced (LTE-A), LTE-Pro, 3GPP2's HRPD (High Rate Packet Data), UMB (Ultra Mobile Broadband), and IEEE's 802.16e.

[0042] As a representative example of the above broadband wireless communication system, the LTE system adopts the Orthogonal Frequency Division Multiplexing (OFDM) method in the downlink (DL) and the Single Carrier Frequency Division Multiple Access (SC-FDMA) method in the uplink (UL). The uplink refers to a wireless link in which a terminal (User Equipment (UE) or Mobile Station (MS)) transmits data or control signals to a base station (eNode B, gNode B, or base station (BS)), and the downlink refers to a wireless link in which a base station transmits data or control signals to a terminal. The above multiple access method can distinguish the data or control information of each user by allocating and operating the time-frequency resources for transmitting data or control information to each user so that they do not overlap, that is, so as to achieve orthogonality.

[0043] As a future communication system beyond LTE, 5G communication systems must be able to freely reflect the diverse needs of users and service providers. Therefore, they must support services that simultaneously satisfy these diverse requirements. Services being considered for 5G communication systems include enhanced Mobile Broadband (eMBB), massive Machine Type Communication (mMTC), and Ultra-Reliable Low Latency Communication (URLLC).

[0044] eMBB aims to provide data transmission rates that are significantly higher than those supported by existing LTE, LTE-A, or LTE-Pro. For example, in a 5G communication system, eMBB must be able to support a peak data rate of 20 Gbps in the downlink and a peak data rate of 10 Gbps in the uplink from the perspective of a single base station. Furthermore, 5G communication systems must simultaneously provide the peak data rate and an increased user-perceived data rate for terminals. To meet these requirements, improvements in various transmission and reception technologies, including improved multi-input, multi-output (MIMO) transmission technology, are required. Furthermore, while LTE transmits signals using a maximum transmission bandwidth of 20 MHz in the 2 GHz band, 5G communication systems can meet the data transmission rates required by 5G communication systems by using a wider frequency bandwidth than 20 MHz in the 3-6 GHz or higher 6 GHz band.

[0045] At the same time, mMTC is being considered to support application services such as the Internet of Things (IoT) in 5G communication systems. To efficiently provide the IoT, mMTC requires supporting large-scale terminal connections within a cell, improved terminal coverage, enhanced battery life, and reduced terminal costs. The IoT requires the ability to support a large number of terminals (e.g., 1,000,000 terminals / km^2) within a cell, as it provides communication capabilities through the attachment of various sensors and devices. Furthermore, due to the nature of the service, terminals supporting mMTC are likely to be located in shadow areas, such as basements, beyond the reach of cells. Therefore, they may require wider coverage than other services provided by 5G communication systems. Terminals supporting mMTC must be inexpensive, and since frequent battery replacement is unlikely, they may require extremely long battery lifespans, such as 10 to 15 years.

[0046] Finally, URLLC refers to cellular-based wireless communication services used for specific mission-critical purposes. Examples include remote control of robots or machinery, industrial automation, unmanned aerial vehicles (UAVs), remote health care, and emergency alerts. Therefore, URLLC communications must offer extremely low latency and high reliability. For example, services supporting URLLC must meet air interface latency requirements of less than 0.5 milliseconds and a packet error rate (PER) of less than 10^-5. Therefore, for services supporting URLLC, 5G systems must provide shorter transmission time intervals (TTIs) than other services, and design requirements may require the allocation of extensive resources in the frequency band to ensure communication link reliability.

[0047] The three 5G services—eMBB, URLLC, and mMTC—can be multiplexed and transmitted within a single system. To meet the differing requirements of each service, different transmission and reception techniques and parameters can be used. Of course, 5G is not limited to the three services described above.

[0048] In this disclosure, phrases such as “A and / or B,” “A or B,” “at least one of A and B,” “at least one of A or B,” “A, B, or C,” “at least one of A, B, and C,” and “at least one of A, B, or C” can each include any one of the items listed together in that phrase, or all possible combinations thereof. Terms such as “first,” “second,” or “first” or “second” may be used merely to distinguish the corresponding component from other corresponding components and do not limit the corresponding components in any other respect (e.g., importance or order).

[0049] Hereinafter, the base station is an entity that performs resource allocation of a terminal, and may be at least one of a Node B, a BS (Base Station), an eNB (eNode B), a gNB (gNode B), a wireless access unit, a base station controller, or a node on a network. The terminal may include a UE (User Equipment), an MS (Mobile Station), a cellular phone, a smartphone, a computer, or a multimedia system capable of performing a communication function. In addition, the embodiments of the present disclosure may be applied to other communication systems having a similar technical background or channel form to the embodiments of the present disclosure described below. In addition, the embodiments of the present disclosure may be applied to other communication systems through some modifications without significantly departing from the scope of the present disclosure at the discretion of a person having skilled technical knowledge.

[0050] In the present disclosure, network technology may refer to standard specifications defined by the International Telecommunication Union (ITU) or 3GPP (e.g., TS 23.501, TS 23.502, TS 23.503, etc.), and components included in the network structure of FIG. 1 may each mean a physical entity, or may mean software performing an individual function, or hardware combined with software. Reference symbols shown as Nx, such as N1, N2, N3, ... in the drawings, represent known interfaces between NFs in a 5G core network (CN), and since a related description may refer to the standard specification (TS 23.501), a detailed description will be omitted.

[0051] In the following description, terms used to identify connection nodes, terms referring to network entities (NEs) or network functions (NFs), terms referring to messages, terms referring to interfaces between network objects, terms referring to various identification information, etc. are provided as examples for convenience of explanation. Therefore, the present disclosure is not limited to the terms described below, and other terms referring to objects having equivalent technical meanings may be used.

[0052] For convenience of explanation, some terms and names defined in the 3rd generation partnership project long-term evolution (3GPP) standards 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.

[0053] FIG. 1 is a diagram showing an example of a configuration of a wireless communication system according to an embodiment of the present disclosure, and FIG. 1 exemplifies the configuration of a 5G system.

[0054] Referring to FIG. 1, a 5G network may include at least one of the network entities (NE) or network functions (NF) described below.

[0055] (R)AN ((radio) access network) is an entity that performs radio resource allocation of a terminal, and may be at least one of an eNode B, a Node B, a BS (base station), an NG-RAN (next generation radio access network), a 5G-AN (5G access network), a 5G NR (5G new radio), a radio access unit, a base station controller, or a node on a network.

[0056] The terminal may include a UE (user equipment), NG UE (next generation UE), MS (mobile station), cellular phone, smartphone, computer, IoT (Internet of Things) device, or multimedia system capable of performing communication functions.

[0057] Furthermore, while the embodiments of the present disclosure are described below using a 5G system as an example, the embodiments of the present disclosure can also be applied to other communication systems with similar technical backgrounds. Furthermore, the embodiments of the present disclosure can be applied to other communication systems with some modifications, as determined by a person skilled in the art, without significantly departing from the scope of the present disclosure.

[0058] As wireless communication systems evolve from 4G to 5G, a new core network (CN) called NG Core (next generation core) or 5GC (5G core network) is defined. This new core network virtualizes all existing network entities (NEs) into network functions (NFs). According to one embodiment of the present disclosure, a network function may refer to a network entity, a network component, or a network resource.

[0059] According to one embodiment of the present disclosure, 5GC may include NFs illustrated in FIG. 1. Of course, the present invention is not limited to the example illustrated in FIG. 1, and 5GC may include more or fewer NFs than the NFs illustrated in FIG. 1.

[0060] The Access and Mobility Management Function (AMF) may be a network function that manages the access and mobility of a terminal (UE). For example, AMF may perform network functions such as terminal registration, connection, reachability, mobility management, access verification, authentication, and mobility event generation.

[0061] A session management function (SMF) may be a network function that manages a packet data network (PDN) connection provided to a user equipment (UE). A PDN connection may be referred to as a protocol data unit (PDU) session. For example, an SMF may perform network functions such as session management through establishing, modifying, and releasing sessions, maintaining tunnels between a user plane function (UPF) and the RAN, selecting and controlling a user plane (UPF), controlling traffic processing in the UPF, and controlling the collection of charging data.

[0062] PCF (policy control function) may be a network function that applies the mobile carrier's service policy, charging policy, and policy for PDU sessions to terminals.

[0063] Unified Data Management (UDM) can be a network function that stores subscriber information. For example, UDM can perform functions such as generating authentication information for 3GPP security, processing user identifiers (User IDs), managing a list of network functions supporting UEs, and managing subscription information.

[0064] The network exposure function (NEF) may provide terminal information to servers outside the 5G network. Additionally, NEF may provide the information necessary for 5G network services and store it in a unified data repository (UDR).

[0065] The user plane function (UPF) may function as a gateway that transmits user data (PDU) to the data network (DN). More specifically, the UPF may process data so that it can transmit data transmitted by a terminal to an external network or transmit data received from an external network to the terminal. For example, the UPF may perform network functions such as serving as an anchor between radio access technologies (RATs), packet routing and forwarding, packet inspection, user plane policy application, traffic usage report generation, and buffering.

[0066] NRF (network repository function) can store the profiles of NFs and perform the function of discovering NFs.

[0067] AUSF (authentication server function) can perform terminal authentication in 3GPP access networks and non-3GPP access networks.

[0068] NSSF (network slice selection function) can perform the function of selecting a network slice instance provided to a terminal.

[0069] The Network Data Analytics Function (NWDAF) collects data from multiple network functions (NFs) to ensure efficient operation of the 5GC network. This data is analyzed using a machine learning (ML) model, and the results are provided back to the NFs, helping them provide efficient network services.

[0070] An application function (AF) can communicate with a network operator to enable external servers (application servers) to utilize network services provided by the network operator. Depending on the deployment entity, AFs can be divided into internal AFs and external AFs. Internal AFs deployed by network operators can communicate directly with network functions (NFs) within the network operator. AFs deployed by third-party service providers (3rd-party service providers) must go through an NEF to communicate with NFs within the network operator.

[0071] DN (data network) can be a data network where terminals transmit and receive data to use network operator services or third-party services.

[0072] The terminal may include an IoT device. The IoT device may include a device that does not use battery power or operates with very little power, and such IoT devices are referred to as ambient IoT devices (or simply Ambient IoT).

[0073] In the 3GPP system, a conceptual link connecting NFs within a 5G system is defined as a reference point. The following illustrates a reference point included in the 5G system architecture depicted in Figure 1.

[0074] - N1: Reference point between UE and AMF

[0075] - N2: Reference point between (R)AN and AMF

[0076] - N3: Reference point between (R)AN and UPF

[0077] - N4: Reference point between SMF and UPF

[0078] - N5: Reference point between PCF and AF

[0079] - N6: Reference point between UPF and DN

[0080] - N7: Reference point between SMF and PCF

[0081] - N8: Reference point between UDM and AMF

[0082] - N9: Reference point between two core UPFs

[0083] - N10: Reference point between UDM and SMF

[0084] - N11: Reference point between AMF and SMF

[0085] - N12: Reference point between AMF and AUSF

[0086] - N13: Reference points between UDM and AUSF

[0087] - N14: Reference point between two AMFs

[0088] Additionally, in 3GPP systems, the 5G system architecture may include service-based interfaces such as the following examples:

[0089] - Nnssf: Service-based interface by NSSF

[0090] - Nnssaaf: Service-based interface by NSSAAF (network slice-specific authentication and authorization function)

[0091] - Nnef: Service-based interface by NEF

[0092] - Nausf: Service-based interface by AUSF

[0093] - Nnrf: Service-based interface by NRF

[0094] - Namf: Service-based interface by AMF

[0095] - Npcf: Service-based interface by PCF

[0096] - Nsmf: Service-based interface by SMF

[0097] - Nupf: Service-based interface by UPF

[0098] - Nudm: Service-based interface by UDM

[0099] - Naf: Service-based interface by AF

[0100] - Nasaf: Service-based interface by AUSF

[0101] - Neasdf: Service-based interface by EASDF (edge ​​application server discovery function)

[0102] - Nnwdaf: Service-based interface by NWDAF

[0103] Additionally, terms used in this disclosure are defined as follows.

[0104] ProSe (ProSe Service or Proximity-based Service) refers to a service that enables discovery, direct communication between physically close devices, communication via a base station, or communication via a third-party device. In this case, user plane data is exchanged directly through a data path without going through the core network.

[0105] A ProSe-enabled UE (proximity service-enabled UE) refers to a UE that supports ProSe discovery and / or ProSe communication.

[0106] ProSe UE-to-Network Relay (Proximity Service UE-to-Network Relay, ProSe UE-to-Network Relay) is a ProSe-enabled UE, and refers to a form of relay that operates as a communication relay between a ProSe-enabled UE and a network.

[0107] ProSe UE-to-UE Relay (Proximity Service UE-to-UE Relay, ProSe Terminal-to-Terminal Relay) is a ProSe-enabled UE and refers to a type of relay that operates as a proximity service communication relay between ProSe-enabled UEs.

[0108] ProSe discovery (proximity service discovery) refers to the process by which a ProSe-enabled UE identifies whether there are other ProSe-enabled UEs or ProSe relays providing nearby services.

[0109] FIG. 2 illustrates a 5G ProSe (proximity based services) UE-to-UE Relay structure according to one embodiment of the present disclosure.

[0110] Referring to FIG. 2, both the 5G ProSe End UE (210, 230) and the 5G ProSe UE-to-UE Relay (220) are 5G ProSe enabled UEs, and the 5G ProSe End UE (210, 230) can communicate with the counterpart 5G ProSe End UE (230, 210) using the 5G ProSe UE-to-UE Relay (220). The 5G ProSe UE-to-UE Relay (220) can provide a data relay service to enable the 5G ProSe End UEs (210, 230) to communicate. Additionally, 5G ProSe enabled UEs (5G ProSe End UEs (210, 230) and 5G ProSe UE-to-UE Relay (220)) can use the PC5 interface to transmit data and / or signaling.

[0111] FIG. 3 illustrates a 5G ProSe UE-to-Network Relay structure according to one embodiment of the present disclosure.

[0112] Referring to FIG. 3, both the 5G ProSe Remote UE (310) and the 5G ProSe UE-to-Network Relay (5G ProSe terminal-to-network relay, layer-3 terminal-to-network relay) (320) are 5G ProSe enabled UEs, and the 5G ProSe Remote UE (310) can communicate with the NG-RAN (network) (330) using the 5G ProSe UE-to-Network relay (320). In addition, the NG-RAN (320) can be connected to a data network (350) through the 5GC (5G core) (330). In addition, the 5G ProSe UE-to-Network Relay (320) can provide a data relay service so that the 5G ProSe Remote UEs (310) can communicate with the network.

[0113] Additionally, the PC5 interface may be used to transmit data and / or signaling between the 5G ProSe Remote UE (310) and the 5G ProSe UE-to-Network Relay (320), and the Uu interface may be used to transmit data and / or signaling between the 5G ProSe UE-to-Network Relay (320) and the NG-RAN (network) (330). And the N6 interface may be used to transmit data and / or signaling between the 5GC (340) and the data network (350).

[0114] FIG. 4 illustrates a model A scheme for 5G ProSe Relay discovery according to one embodiment of the present disclosure.

[0115] Referring to FIG. 4, Model A is a model that uses a single discovery protocol message (announcement message). In Model A, a 5G ProSe Relay (420) can transmit the relay service it can provide in the form of a relay service code (RSC), for example, a 5G ProSe Relay Discovery Announcement message (UE-to-UE relay discovery broadcast message) to surrounding 5G ProSe End UEs (410, 430) (440, 445). The 5G ProSe Relay (420) can include a 5G ProSe UE-to-UE Relay and a 5G ProSe UE-to-Network Relay. The 5G ProSe End UE (410, 430) is a ProSe enabled UE.

[0116] The 5G ProSe End UE (410, 430) that receives the above 5G ProSe Relay Discovery Announcement message can determine the 5G ProSe Relay (420) that provides the relay service to be used based on the RSC and initiate relay communication using the 5G ProSe Relay (420).

[0117] FIG. 5 illustrates a 5G ProSe Relay discovery model B scheme according to one embodiment of the present disclosure.

[0118] Referring to FIG. 5, the Model B scheme is a model that uses two discovery protocol messages (e.g., a solicitation message and a response message). In the Model B scheme, a 5G ProSe End UE (510) may transmit, for example, a 5G ProSe Relay Discovery Solicitation message (a 5G ProSe UE-to-UE Discovery Request message) to a neighboring 5G ProSe Relay (including a 5G ProSe UE-to-UE Relay and a 5G ProSe UE-to-Network Relay) (520) to use a relay service. This message may include an RSC value of a ProSe service to be used by the 5G ProSe End UE.

[0119] The 5G ProSe Relay (520) that receives the 5G ProSe Relay Discovery Solicitation message can confirm whether the 5G ProSe Relay Discovery Solicitation message is a relay service provided by itself based on the RSC value and then relay the 5G ProSe Relay Discovery Solicitation message to the corresponding 5G ProSe End UE (530). Alternatively, the 5G ProSe Relay (520) that receives the 5G ProSe Relay Discovery Solicitation message can generate a 5G ProSe Relay Discovery Response message in response to the Solicitation message and transmit the Response message to the 5G ProSe End UE (510) that transmitted the Discovery Solicitation, thereby completing the Relay Discovery procedure.

[0120] In order to perform 5G ProSe communication using 5G ProSe UE-to-UE Relay and 5G ProSe UE-to-Network Relay, 5G ProSe Relay discovery is required, and as shown in FIGS. 4 and 5, two models (Model A and Model B) can be supported for 5G ProSe Relay discovery.

[0121] Additionally, a 5G ProSe enabled UE can receive information from the network about its authority to provide or use the 5G ProSe Relay function through authorization and parameters provisioning. Each 5G ProSe enabled UE can receive from the network the authority to provide relay services as a 5G ProSe UE-to-Network Relay or 5G ProSe UE-to-UE Relay and / or the authority to use the relay service.

[0122] Additionally, the 5G ProSe enabled UE may also receive authorization to use Model A and / or Model B for 5G ProSe Relay discovery. Finally, the 5G ProSe enabled UE may also receive a validity time for the validity period of the received authorization and / or parameters.

[0123] FIG. 6 illustrates a procedure of a 5G ProSe UE-to-UE Relay Discovery Model B scheme according to an embodiment of the present disclosure.

[0124] Referring to FIG. 6, at step 610, (discoverer) 5G ProSe End UE-1 (601) may perform a 5G ProSe UE-to-UE Relay Discovery Model B procedure to communicate with (discoveree) 5G ProSe End UE-2 (605). To this end, UE-1 (601) may transmit a 5G ProSe UE-to-UE Relay Discovery Solicitation message. The 5G ProSe UE-to-UE Relay Discovery Solicitation message may include at least one of a Type of Discovery Message, a User Info ID of UE-1 (601), a User Info ID of UE-2 (605), and an RSC value. To transmit the message, the Source Layer-2 ID value may be assigned a value arbitrarily set by UE-1 (601), and the Destination Layer-2 ID value may be set to a Default ID value. The Layer-2 ID value can be an address value that 5G ProSe enabled UEs use to confirm whether a message received is a message sent to themselves. In particular, since the Default ID value means Broadcast, if this value is assigned as the destination (Destination Layer-2 ID) address, all terminals can receive this message. For example, a message transmitted by UE-1 (601) can be received by 5G ProSe UE-to-UE Relay-1 (602), 5G ProSe UE-to-UE Relay-2 (603), and 5G ProSe UE-to-UE Relay-3 (604).

[0125] At step 620, 5G ProSe UE-to-UE Relay-1 (602), 5G ProSe UE-to-UE Relay-2 (603), and 5G ProSe UE-to-UE Relay-3 (604), which have received the 5G ProSe UE-to-UE Relay Discovery Solicitation message transmitted by UE-1 (601), can check the received message. At this time, each Relay (5G ProSe UE-to-UE Relay-1 (602), 5G ProSe UE-to-UE Relay-2 (603), and 5G ProSe UE-to-UE Relay-3 (604)) can check the RSC value in the message. Relay (602, 603, 604) can check whether the RSC value included in the received message is the RSC it serves, and if it is the same as the RSC value it serves, it can create and transmit a 5G ProSe UE-to-UE Relay Discovery Solicitation message. If it is not the same as the RSC value, Relay (602, 603, 604) can ignore this message. In Fig. 6, Relay-1 (602) and Relay-2 (603) support the RSC service and thus transmit the 5G ProSe UE-to-UE Relay Discovery Solicitation message, but Relay-3 (604) does not support it and thus may ignore and not transmit the message. The 5G ProSe UE-to-UE Relay Discovery Solicitation message transmitted by Relay (602, 603) may include at least one of the following information.

[0126] - Type of Discovery Message, User Info ID of discoverer 5G ProSe End UE (UE-1(601)), User Info ID of discoveree 5G ProSe End UE (UE-2(605)), User Info ID of 5G ProSe UE-to-UE Relay (602, 603), and RSC.

[0127] In order for Relay (602, 603) to transmit a 5G ProSe UE-to-UE Relay Discovery Solicitation message, the Source Layer-2 ID value can be assigned a value arbitrarily set by itself (602, 603), and the Destination Layer-2 ID value can be set to a Default ID value. In addition, Relay (602, 603) can store the Source Layer-2 ID value and RSC value of UE-1 (601) in order to provide a retransmission service.

[0128] At step 630, the (discoveree) 5G ProSe End UE (UE-2) (605) can receive the 5G ProSe UE-to-UE Relay Discovery Solicitation message transmitted by Relay-1 (602) and Relay-2 (603). UE-2 (605) can receive the message and check the RSC value and the User Info ID of the discoveree 5G ProSe End UE (UE-2 (605)). UE-2 (605) can check whether the RSC value included in the received message is the same as the RSC value of the service to which it has subscribed and check the User Info ID value to confirm whether the message has been sent to it. UE-2 (605) can select one of the messages received from multiple Relays and transmit a 5G ProSe UE-to-UE Relay Discovery Response message to the Relay that transmitted the message. The method of selecting one of the multiple 5G ProSe UE-to-UE Relay Discovery Solicitation messages received by UE-2 (605) can be selected by considering the strength of the received message signal, the time at which the message was received, etc. The 5G ProSe UE-to-UE Relay Discovery Response message transmitted by UE-2 (605) may include at least one of the following information.

[0129] - Type of Discovery Message, User Info ID of discoverer 5G ProSe End UE (UE-1(601)), User Info ID of discoveree 5G ProSe End UE (UE-2(605)), and RSC.

[0130] In order for UE-2 (601) to transmit this 5G ProSe UE-to-UE Relay Discovery Response message, it can assign a value arbitrarily set as the Source Layer-2 ID value and assign the Source Layer-2 ID value of the 5G ProSe UE-to-UE Relay Discovery Solicitation message it received as the Destination Layer-2 ID value. In other words, this 5G ProSe UE-to-UE Relay Discovery Response message is not a broadcast but a unicast transmission directed to a specific Relay (602, 603). In this embodiment, the address of Relay-2 (603) can be assigned. The 5G ProSe UE-to-UE Relay Discovery Response message can be received by Relay-1 (602) and Relay-2 (603), but since the destination address included in the message is Relay-2 (603), only Relay-2 (603) receives (receives and decodes) the message, and Relay-1 (602) can ignore the received message.

[0131] At step 640, the Relay (Relay-2) (603) that receives the 5G ProSe UE-to-UE Relay Discovery Response message transmitted by UE-2 (605) may generate a 5G ProSe UE-to-UE Relay Discovery Response message and transmit it to the discoverer 5G ProSe End UE (UE-1) (601). This message may include at least one of the following information: Type of Discovery Message, User Info ID of discoveree 5G ProSe End UE (UE-2 (605)), User Info ID of 5G ProSe UE-to-UE Relay (603), and RSC. In order for Relay-2 (603) to transmit this message, the Source Layer-2 ID value may be assigned a value arbitrarily set by the Relay. Relay-2 (602) can set the Destination Layer-2 ID value by checking the User Info ID of discoverer 5G ProSe End UE (UE-1 (601)) and RSC included in the 5G ProSe UE-to-UE Relay Discovery Response message and using the Source Layer-2 ID value of UE-1 (601) stored in step 620. Therefore, the message can be unicast to the (discoverer) 5G ProSe End UE (UE-1 (601)).

[0132] FIG. 7 illustrates a procedure for establishing a Layer-2 link for PC5 communication using a 5G ProSe Layer-3 UE-to-UE Relay according to an embodiment of the present disclosure.

[0133] Referring to FIG. 7, at step 710, service authorization and provisioning procedures may be performed for a Source 5G ProSe Layer-3 End UE (701), a Target 5G ProSe Layer-3 End UE (703), and a 5G ProSe Layer-3 UE-to-UE Relay (702).

[0134] The 5G ProSe UE-to-UE Relay discovery procedure exemplarily described in FIG. 6 may be performed at step 720.

[0135] At step 730, the Source 5G ProSe Layer-3 End UE (701) may transmit a Direct Communication Request message to the 5G ProSe Layer-3 UE-to-UE Relay (702) to establish a unicast Layer-2 link with the 5G ProSe Layer-3 UE-to-UE Relay (702). This message may include at least one of the following information: User Info ID of the Source 5G ProSe End UE (701), User Info ID of the 5G ProSe UE-to-UE Relay (702), User Info ID of the Target 5G ProSe End UE (703), (optional) Destination Layer-2 ID of the Target 5G ProSe End UE (703), ProSe Service Info, RSC, and Security Information.

[0136] The Source Layer-2 ID of the Direct Communication Request message can be autonomously assigned by the Source 5G ProSe Layer-3 End UE (701). The Source 5G ProSe Layer-3 End UE (701) can assign the Destination Layer-2 ID using the Source Layer-2 ID of the discovery message transmitted by the 5G ProSe UE-to-UE Relay (702) in the 5G ProSe UE-to-UE Relay discovery procedure. Accordingly, the Direct Communication Request message can be transmitted to the 5G ProSe UE-to-UE Relay (702) as a unicast.

[0137] The 5G ProSe Layer-3 UE-to-UE Relay (702) that receives the Direct Communication Request message at step 735 can compare the User Info ID of the 5G ProSe Layer-3 UE-to-UE Relay in the received message with its own User Info ID and compare the RSC value in the message with the RSC value it serves. If these values ​​match, the 5G ProSe Layer-3 UE-to-UE Relay (702) can transmit a response message to the Source 5G ProSe Layer-3 End UE (701) to establish a security relationship with the Source 5G ProSe Layer-3 End UE (701). When security protection is established between two UEs (Source 5G ProSe Layer-3 End UE (701), 5G ProSe Layer-3 UE-to-UE Relay (702)), the Source 5G ProSe Layer-3 End UE (701) may transmit at least one of the following information to the 5G ProSe Layer-3 UE-to-UE Relay (702): IP Address Configuration or Link-Local IPv6 Address, QoS Info of End-to-End QoS. If Ethernet traffic is transmitted using the PC5 link, the Ethernet MAC address may be transmitted instead of IP-related information.

[0138] If the Ethernet MAC address provided by the Source 5G ProSe Layer-3 End UE (701) is the same as that of another 5G ProSe Layer-3 End UE, smooth communication may be difficult due to a collision of Ethernet MAC addresses. Therefore, if a collision of MAC addresses occurs, the 5G ProSe UE-to-UE Relay (702) can notify the Source 5G ProSe Layer-3 End UE (701) by sending a message and cancel the subsequent procedure.

[0139] The Source Layer-2 ID used in the Security Establishment procedure can be configured by the 5G ProSe Layer-3 UE-to-UE Relay (702). The 5G ProSe Layer-3 UE-to-UE Relay (702) can configure the Destination Layer-2 ID using the Source Layer-2 ID of the Direct Communication Request message.

[0140] The 5G ProSe Layer-3 UE-to-UE Relay (702) can select different Source Layer-2 IDs for each type of traffic (e.g., IP traffic, Ethernet traffic, Unstructured traffic) to transmit different types of traffic to the PC5 link.

[0141] For example, if a PC5 link is used to transmit unstructured traffic, the 5G ProSe Layer-3 UE-to-UE Relay (702) may select a Source Layer-2 ID that is different from the Source Layer-2 ID assigned to the PC5 link used to transmit other unstructured traffic.

[0142] The Source 5G ProSe Layer-3 End UE (701) that received the message for the security establishment procedure can store the Layer-2 ID of the 5G ProSe Layer-3 UE-to-UE Relay (702). The 5G ProSe Layer-3 UE-to-UE Relay Layer-2 ID can be used later to transmit signaling or traffic in unicast.

[0143] At step 740, the 5G ProSe Layer-3 UE-to-UE Relay (702) may transmit a Direct Communication Request message to the Target 5G ProSe Layer-3 End UE (703). Based on the Direct Communication Request message, the 5G ProSe Layer-3 UE-to-UE Relay (702) may initiate a Layer-2 link establishment procedure with the Target 5G ProSe Layer-3 UE (703). The Direct Communication Request message may include at least one of the following information: User Info ID of Source 5G ProSe End UE (701), User Info ID of Target 5G ProSe End UE (703), User Info ID of 5G ProSe UE-to-UE Relay (702), ProSe Service Info, RSC, and Security Information. Of course, the present invention is not limited to the above examples.

[0144] To transmit a Direct Communication Request message, the Source Layer-2 ID can be randomly assigned by the 5G ProSe Layer-3 UE-to-UE Relay (702). The 5G ProSe Layer-3 UE-to-UE Relay (702) can assign the Destination Layer-2 ID using the Layer-2 ID associated with the User Info ID of the Target 5G ProSe Layer-3 End UE (703). Accordingly, the Direct Communication Request message can be transmitted to the Target 5G ProSe Layer-3 End UE (703) as a unicast.

[0145] 5G ProSe Layer-3 UE-to-UE Relay can select different Source Layer-2 IDs for different types of traffic (e.g. IP traffic, Ethernet traffic, Unstructured traffic) to transmit them to the PC5 link.

[0146] For example, if a PC5 link is used to transmit unstructured traffic, the Source Layer-2 ID and the Source Layer-2 ID assigned to the PC5 link used to transmit other unstructured traffic can be selected.

[0147] At step 745, the Target 5G ProSe Layer-3 End UE (703) can identify (verify) the User Info ID value and RSC value of the Target 5G ProSe Layer-3 End UE (703) included in the received Direct Communication Request message. The Target 5G ProSe Layer-3 End UE (703) compares the User Info ID value of the Target 5G ProSe Layer-3 End UE (703) and the RSC value subscribed to by the Target 5G ProSe Layer-3 End UE (703) with the above-described values ​​and confirms that they are the same, and then can start the 5G ProSe Layer-3 UE-to-UE Relay (702) and Security Establishment procedure.

[0148] When security protection is activated between the target 5G ProSe Layer-3 End UE (703) and the 5G ProSe UE-to-UE Relay (702), the 5G ProSe Layer-3 UE-to-UE Relay (702) may transmit at least one of the following information to the target 5G ProSe Layer-3 End UE (703): IP Address Configuration or Link-Local IPv6 Address and QoS Info of end-to-end QoS. Of course, the present invention is not limited to the above examples.

[0149] If the PC5 link transmits Ethernet traffic, the 5G ProSe Layer-3 UE-to-UE Relay can transmit the Ethernet MAC address of the Source 5G ProSe Layer-3 End UE (701) instead of IP-related information.

[0150] The Source Layer-2 ID used in the security establishment procedure between the 5G ProSe Layer-3 UE-to-UE Relay (702) and the Target 5G ProSe Layer-3 End UE (703) can be set by the Target 5G ProSe Layer-3 End UE (703). The Target 5G ProSe Layer-3 End UE (703) can set the Destination Layer-2 ID using the Source Layer-2 ID of the Direct Communication Request message.

[0151] The 5G ProSe Layer-3 UE-to-UE Relay (702) that received the message for the security establishment procedure can store the Layer-2 ID of the target 5G ProSe Layer-3 End UE (703). The Layer-2 ID of the target 5G ProSe Layer-3 End UE (703) can be used later for signaling or unicast transmission of traffic.

[0152] At step 750, the target 5G ProSe Layer-3 End UE (703) may transmit a Direct Communication Accept message to the 5G ProSe Layer-3 UE-to-UE Relay (702). The Direct Communication Accept message may indicate that a secure channel has been successfully established between two UEs (the target 5G ProSe Layer-3 End UE (703) and the 5G ProSe Layer-3 UE-to-UE Relay (702)). The message may include at least one of the following information: User Info ID of the target 5G ProSe End UE (703). The Direct Communication Accept message may be transmitted to the 5G ProSe Layer-3 UE-to-UE Relay (702) in unicast.

[0153] At step 755, an IPv6 prefix or IPv4 address for IP traffic can be assigned to the Target 5G ProSe Layer-3 End UE (703).

[0154] At step 760, the 5G ProSe Layer-3 UE-to-UE Relay (702) may transmit a Direct Communication Accept message to the Source 5G ProSe Layer-3 End UE (701). The Direct Communication Accept message may indicate that a secure channel has been successfully established between two UEs (5G ProSe Layer-3 UE-to-UE Relay (702), Source 5G ProSe Layer-3 End UE (701)). The Direct Communication Accept message may include at least one of the following information: User Info ID of target 5G ProSe End UE (703), User Info ID of 5G ProSe UE-to-UE Relay (702). Of course, the present invention is not limited to the above example. In addition, the Direct Communication Accept message may be transmitted to the Source 5G ProSe Layer-3 End UE (701) in unicast.

[0155] At step 765, an IPv6 prefix or IPv4 address for IP traffic can be assigned to the Source 5G ProSe Layer-3 End UE (701).

[0156] In steps 770 and 775, for IP communication, the 5G ProSe Layer-3 UE-to-UE Relay (702) can store the association of the User Info ID and IP Address of the Target 5G ProSe Layer-3 End UE (703) in its DNS (domain name service, domain name system) entry, and can thus function as a DNS server for other terminals. If the Source 5G ProSe Layer-3 End UE (701) has not received the IP Address of the Target 5G ProSe Layer-3 End UE (703), the Source 5G ProSe Layer-3 End UE (701) can transmit a DNS query to the 5G ProSe Layer-3 UE-to-UE Relay (702) to inquire about the IP Address of the Target 5G ProSe Layer-3 End UE (703).

[0157] For Ethernet communication, the 5G ProSe Layer-3 UE-to-UE Relay (702) can maintain the association of the PC5 link and the Ethernet MAC Address received from the 5G ProSe Layer-3 End UE.

[0158] For unstructured traffic communication, the 5G ProSe Layer-3 UE-to-UE Relay (702) can store, maintain, and update 1:1 mapping information of the PC5 link associated with the Source 5G ProSe Layer-3 End UE (701) and the PC5 link associated with the Target 5G ProSe Layer-3 End UE (703) for all Source and Target 5G ProSe Layer-3 End UE (701, 703) pairs.

[0159] At step 780, the Source 5G ProSe Layer-3 End UE (701) can communicate with the Target 5G ProSe Layer-3 End UE (703) through the 5G ProSe Layer-3 UE-to-UE Relay (702).

[0160] In this disclosure, a method for solving a problem that occurs when a 5G ProSe Layer-3 UE-to-UE Relay (702) transmits a Direct Communication Request message to a Target 5G ProSe Layer-3 End UE (703) at step 740 of FIG. 7 is proposed.

[0161] The 5G ProSe UE-to-UE Relay Discovery Model B procedure, which is exemplarily described in FIG. 6 and is a discovery procedure of step 720 of FIG. 7, may have issues in some steps. The User Info ID of discoverer 5G ProSe End UE (UE-1 (601, 701)) and the User Info ID of discoveree 5G ProSe End UE (UE-2 (605, 703)) values ​​are stored in a container called protected direct discovery set for security reasons. That is, these values ​​may be values ​​that only UE-1 (601, 701) and UE-2 (605, 703) can see, and Relay (602, 603, 604, 702) may not be able to see. For this reason, in step 740 of FIG. 7, the 5G ProSe Layer-3 UE-to-UE Relay (702) cannot check the User Info ID of the Target 5G ProSe Layer-3 End UE (703) and unicast using the corresponding Layer-2 ID. A solution to this problem is proposed.

[0162] The first solution is to define a new ID (or index) that can identify the value of the pair of Layer-2 ID of the Source 5G ProSe Layer-3 End UE (701) and Layer-2 ID of the Target 5G ProSe Layer End UE (703) within the 5G ProSe Layer-3 UE-to-UE Relay (702) instead of the User Info ID. This ID can be unique within the 5G ProSe Layer-3 UE-to-UE Relay (702).

[0163] During the 5G ProSe UE-to-UE Relay Discovery procedure of FIG. 6 corresponding to step 720 of FIG. 7, when 5G ProSe UE-to-UE Relay-2 (603) transmits a UE-to-UE Relay Discovery Response message to 5G ProSe End UE-1 (601) at step 640, a specific value (e.g., an index value) may be included in this message and transmitted. This specific value (index value) may be a value for identifying an entry that maps the Source Layer-2 ID value included in the UE-to-UE Relay Discovery Response message received from the 5G ProSe End UE-2 (605) at step 630 by the 5G ProSe UE-to-UE Relay-2 (602) to the Source Layer-2 ID value assigned by the 5G ProSe UE-to-UE Relay-2 (603) when transmitting the UE-to-UE Relay Discovery Response message to the 5G ProSe End UE-1 (601) at step 640.

[0164] During the Layer-2 link setup procedure of FIG. 7, at step 730, the Source 5G ProSe Layer-3 End UE (701) may transmit a Direct Communication Request message to the 5G ProSe Layer-3 UE-to-UE Relay (702) including a specific value (e.g., index value) received during the Discovery procedure at step 720. At step 740, the 5G ProSe Layer-3 UE-to-UE Relay (702) may use the specific value (index value) received from the Source 5G ProSe Layer-3 End UE (701) at step 730 to identify the Layer-2 ID of the Target 5G ProSe Layer-3 End UE (703). When a 5G ProSe Layer-3 UE-to-UE Relay (702) transmits a Direct Communication Request message to a Target 5G ProSe Layer-3 End UE (701), the Destination Layer-2 ID value can be set to a Layer-2 ID value searched using a specific value (index value) and transmitted to the Target 5G ProSe Layer-3 End UE (703) as a Unicast.

[0165] The second method can distinguish the Layer-2 ID of the Source 5G ProSe Layer-3 End UE (701) and the Layer-2 ID of the Target 5G ProSe Layer End UE (703) within the 5G ProSe Layer-3 UE-to-UE Relay (702) by using the Layer-2 ID instead of the User Info ID. The 5G ProSe Layer-3 UE-to-UE Relay (702) does not uniquely assign the Source Layer-2 ID of the message. Therefore, since there are pairs assigned the same Layer-2 ID, the entries cannot be distinguished using this. Therefore, in the second method, the 5G ProSe Layer-3 UE-to-UE Relay (702) uniquely assigns the Source Layer-2 ID of the message to provide a method for distinguishing the entries of the pair of the Source 5G ProSe Layer-3 End UE (701) and the Target 5G ProSe Layer End UE (703).

[0166] During the 5G ProSe UE-to-UE Relay Discovery procedure of FIG. 6, when the 5G ProSe UE-to-UE Relay-2 (603) transmits a UE-to-UE Relay Discovery Response message to the 5G ProSe End UE-1 (601) at step 640, the Source Layer-2 ID value may be set to a unique value and transmitted. When the 5G ProSe UE-to-UE Relay (603) receives a UE-to-UE Relay Discovery Response message from the 5G ProSe End UE-2 (605) at step 630, the 5G ProSe UE-to-UE Relay (603) may store an entry that maps the Source Layer-2 ID value included in the message and the Source Layer-2 ID value assigned by the 5G ProSe UE-to-UE Relay-2 (603) when transmitting the UE-to-UE Relay Discovery Response message to the 5G ProSe End UE-1 (601) at step 640.

[0167] During the Layer-2 link setup procedure of FIG. 7, at step 730, the Source 5G ProSe Layer-3 End UE (701) can transmit a Direct Communication Request message to the 5G ProSe Layer-3 UE-to-UE Relay (702). At step 740, the 5G ProSe Layer-3 UE-to-UE Relay (702) can use the Destination Layer-2 ID of the message received from the Source 5G ProSe Layer-3 End UE (701) at step 730 to identify the Layer-2 ID of the Target 5G ProSe Layer-3 End UE (703). When transmitting a Direct Communication Request message to a Target 5G ProSe Layer-3 End UE (703), the 5G ProSe Layer-3 UE-to-UE Relay (702) can use the Destination Layer-2 ID value of the Direct Communication Request message in step 730 to set the searched Layer-2 ID value and transmit it to the Target 5G ProSe Layer-3 End UE (703) as a Unicast.

[0168] FIG. 8 illustrates another procedure for establishing a Layer-2 link for PC5 communication using a 5G ProSe Layer-3 UE-to-UE Relay according to an embodiment of the present disclosure.

[0169] The third method is explained by exemplifying the procedure for setting up a Layer-2 link in Fig. 8.

[0170] In the embodiment illustrated in Fig. 8, the procedure is the same as that of Fig. 7 except for step 840. That is, the operations of steps 720 to 780 exemplarily described in Fig. 7 may correspond to the operations of steps 820 to 880 exemplarily illustrated in Fig. 8. However, in the case of step 840, there may be differences in the following contents from the operations of step 740.

[0171] Referring to FIG. 8, in step 840, the 5G ProSe Layer-3 UE-to-UE Relay (802) can transmit a Direct Communication Request message to the Target 5G ProSe Layer-3 End UE (803) in a Broadcast manner. To this end, the Destination Layer-2 ID of the message can be set to the Default Destination Layer-2 ID. The Default Destination Layer-2 ID is the Destination Layer-2 ID used when transmitting a Broadcast message that all UEs receive. The Target 5G ProSe Layer-3 End UE (803) that receives this message can compare its User Info ID of the Target 5G ProSe Layer-3 End UE (803) in the message with its own User Info ID and compare the RSC value in the message with the RSC value used by itself. If the comparison values ​​are the same, the Target 5G ProSe Layer-3 End UE (803) can recognize the message as having been transmitted to itself. And the operations after step 850 can correspond to the operations after step 750 described in Fig. 7. Therefore, a detailed description thereof will be omitted.

[0172] FIG. 9 is a diagram showing the configuration of a terminal according to an embodiment of the present disclosure.

[0173] Referring to FIG. 9, a terminal according to an embodiment of the present disclosure may include a processor (control unit) (920) that controls the overall operation of the terminal, a transceiver unit (900) including a transmitter and a receiver, and a memory (910). Of course, the present invention is not limited to the above example, and the terminal may include more or fewer components than those illustrated in FIG. 9.

[0174] According to one embodiment of the present disclosure, the transceiver (9800) can transmit and receive signals with network entities or other terminals. The signals transmitted and received with the network entities may include control information and data. In addition, the transceiver (900) can receive signals via a wireless channel, output them to the processor (920), and transmit the signals output from the processor (920) via the wireless channel.

[0175] According to one embodiment of the present disclosure, the processor (920) can control the terminal to perform any one of the operations of the above-described embodiments. Meanwhile, the processor (920), the memory (910), and the transceiver (900) do not necessarily have to be implemented as separate modules, and of course, they can be implemented as a single component in the form of a single chip. In addition, the processor (920) and the transceiver (900) can be electrically connected. In addition, the processor (920) can be an Application Processor (AP), a Communication Processor (CP), a circuit, an application-specific circuit, or at least one processor.

[0176] According to one embodiment of the present disclosure, the memory (910) can store data such as basic programs, application programs, and setting information for the operation of the terminal. In particular, the memory (910) provides the stored data upon request of the processor (920). The memory (910) can be configured as a storage medium or a combination of storage media such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD. In addition, there can be a plurality of memories (910). In addition, the processor (920) can perform the above-described embodiments based on a program for performing the above-described embodiments of the present disclosure stored in the memory (910).

[0177] FIG. 10 is a diagram illustrating a configuration of a base station or network entity according to an embodiment of the present disclosure.

[0178] A network entity according to one embodiment of the present disclosure may include a processor (control unit) (1020) that controls the overall operation of the network entity, a transceiver unit (1000) including a transmitter and a receiver, and a memory (910). Of course, the present invention is not limited to the above example, and the network entity may include more or fewer components than the configuration illustrated in FIG. 10.

[0179] According to one embodiment of the present disclosure, the transceiver (1000) can transmit and receive signals with at least one of other network entities or terminals. The signals transmitted and received with at least one of the other network entities or terminals may include control information and data.

[0180] According to one embodiment of the present disclosure, the processor (1020) can control a network entity to perform any one of the operations described above. Meanwhile, the processor (1020), the memory (1010), and the transceiver (1000) do not necessarily have to be implemented as separate modules, and can of course be implemented as a single component in the form of a single chip. In addition, the processor (1020) and the transceiver (1000) can be electrically connected. In addition, the processor (1020) can be an Application Processor (AP), a Communication Processor (CP), a circuit, an application-specific circuit, or at least one processor.

[0181] According to one embodiment of the present disclosure, the memory (1010) may store data such as basic programs, application programs, and setting information for the operation of a network entity. In particular, the memory (1010) provides the stored data upon request of the processor (1020). The memory (1010) may be configured as a storage medium or a combination of storage media such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD. In addition, there may be a plurality of memories (1010). In addition, the processor (1020) may perform the above-described embodiments based on a program for performing the above-described embodiments of the present disclosure stored in the memory (1010).

[0182] The above network entity may be any one of a base station, AMF, SMF, UPF, PCF, UDM, UDR, NEF, NRF, AF, NSSF, NWDAF, NSACF, AUSF, DN, EASDF, NSSAAF, etc.

[0183] It should be noted that the aforementioned configuration diagrams, examples of control / data signal transmission methods, examples of operational procedures, and configuration diagrams are not intended to limit the scope of the present disclosure. That is, not all components, entities, or operational steps described in the embodiments of the present disclosure should be construed as essential components for implementing the disclosure, and implementations may be made within a scope that does not detract from the essence of the disclosure even if only some components are included. Furthermore, each embodiment may be combined and operated as needed. For example, parts of the methods proposed in the present disclosure may be combined to operate network entities and terminals.

[0184] The operations of the base station or terminal described above can be realized by providing a memory device storing the corresponding program code in any component within the base station or terminal device. That is, the control unit of the base station or terminal device can execute the operations described above by reading and executing the program code stored in the memory device using a processor or CPU (Central Processing Unit).

[0185] The various components and modules of the entity, base station or terminal device described in this specification may be operated using hardware circuits, such as logic circuits based on complementary metal oxide semiconductors, firmware, software and / or hardware and firmware and / or software embedded in a machine-readable medium. For example, various electrical structures and methods may be implemented using electrical circuits such as transistors, logic gates and application-specific semiconductors.

[0186] When implemented in software, a computer-readable storage medium storing one or more programs (software modules) may be provided. The one or more programs stored in the computer-readable storage medium are configured for execution by one or more processors within an electronic device. The one or more programs include instructions that cause the electronic device to execute methods according to the embodiments described in the claims or specification of the present disclosure.

[0187] These programs (software modules, software) may be stored in random access memory, non-volatile memory including flash memory, read only memory (ROM), electrically erasable programmable read only memory (EEPROM), magnetic disc storage device, compact disc ROM (CD-ROM), digital versatile discs (DVDs) or other forms of optical storage device, magnetic cassette. Or, they may be stored in a memory configured as a combination of some or all of these. In addition, each configuration memory may be included in multiple numbers.

[0188] Additionally, the program may be stored in an attachable storage device that is accessible via a communication network such as the Internet, an intranet, a local area network (LAN), a wide local area network (WLAN), a storage area network (SAN), or a combination thereof. Such a storage device may be connected to a device performing an embodiment of the present disclosure via an external port. Additionally, a separate storage device on the communication network may be connected to a device performing an embodiment of the present disclosure.

[0189] In the specific embodiments of the present disclosure described above, components included in the disclosure are expressed in the singular or plural form, depending on the specific embodiment presented. However, the singular or plural expressions are selected to suit the presented situation for convenience of explanation, and the present disclosure is not limited to singular or plural components. Components expressed in the plural form may be composed of singular elements, or components expressed in the singular form may be composed of plural elements.

[0190] Meanwhile, although specific embodiments have been described in the detailed description of the present disclosure, it is obvious 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 the described embodiments, but should be determined not only by the scope of the following claims but also by equivalents of the scope of the claims. In other words, it will be apparent to those skilled in the art to which the present disclosure pertains that other modifications based on the technical idea of ​​the present disclosure are possible. In addition, each of the above embodiments can be combined and operated with each other as needed. For example, parts of the methods proposed in the present disclosure can be combined with each other to operate a base station and a terminal. In addition, although the above embodiments have been presented based on a 5G, NR system, other modifications based on the technical idea of ​​the above embodiments can be implemented with other systems such as LTE, LTE-A, and LTE-A-Pro systems.

[0191] While the detailed description of this disclosure has described specific embodiments, it should be understood that various modifications are possible without departing from the scope of this disclosure. Therefore, the scope of this disclosure should not be limited to the described embodiments, but should be defined not only by the scope of the claims described below, but also by equivalents thereof.

Claims

1. A method performed by a proximity service relay terminal of a wireless communication system, A step of receiving, from a source proximity service terminal, a first direct communication request message including identification information capable of identifying a target proximity service terminal corresponding to the source proximity service terminal; A step of transmitting a second direct communication request message to the target proximity service terminal identified based on the above identification information; A step of receiving a first direct communication response message from the target proximity service terminal; and A method comprising the step of transmitting a second direct communication response message to the source proximity service terminal.

2. In paragraph 1, A step of receiving a first terminal-to-terminal relay discovery request (solicitation) message from the source proximity service terminal; A step of transmitting a second terminal-to-terminal relay discovery request message; A step of receiving a first terminal-to-terminal relay discovery response message from the target proximity service terminal; and A method characterized by further comprising the step of transmitting, to the source proximity service terminal, a second terminal-to-terminal relay discovery response message including the identification information capable of identifying the target proximity service terminal corresponding to the source proximity service terminal.

3. In paragraph 1, A method characterized in that the second direct communication request message is transmitted to the target proximity service terminal by unicast.

4. In paragraph 1, A method characterized by further comprising a step of transmitting the third direct communication request message by broadcast when the proximity service relay terminal cannot identify the target proximity service terminal corresponding to the source proximity service terminal based on the identification information.

5. In a method performed by a source proximity service terminal of a wireless communication system, A step of transmitting, to a proximity service relay terminal, a direct communication request message including identification information capable of identifying a target proximity service terminal corresponding to the source proximity service terminal; A step of receiving a direct communication response message from the proximity service relay terminal based on a direct communication request transmitted to the target proximity service terminal identified based on the above identification information; and A method comprising the step of performing communication with the target proximity service terminal through the proximity service relay terminal.

6. In paragraph 5, A step of transmitting a terminal-to-terminal relay discovery request message to the proximity service relay terminal; and A method further comprising the step of receiving, from the proximity service relay terminal, a terminal-to-terminal relay discovery response message including the identification information capable of identifying the target proximity service terminal corresponding to the source proximity service terminal.

7. In paragraph 5, A method characterized in that a request message according to the direct communication request message is transmitted unicast from the proximity service relay terminal to the target proximity service terminal.

8. In paragraph 5, A method characterized in that, when the proximity service relay terminal cannot identify the target proximity service terminal corresponding to the source proximity service terminal based on the identification information, a request message according to the direct communication request message is transmitted as a broadcast by the proximity service relay terminal.

9. In a proximity service relay terminal of a wireless communication system, Transmitter and receiver; and Connected to the above transmitter and receiver, Receive a first direct communication request message from a source proximity service terminal, the first direct communication request message including identification information that can identify a target proximity service terminal corresponding to the source proximity service terminal, Transmitting a second direct communication request message to the target proximity service terminal identified based on the above identification information, Receive a first direct communication response message from the target proximity service terminal, A proximity service relay terminal including a control unit for transmitting a second direct communication response message to the source proximity service terminal.

10. In the 9th paragraph, the control unit, Receives a first terminal-to-terminal relay discovery request message from the source proximity service terminal, Transmit a second terminal-to-terminal relay discovery request message, Receive a first terminal-to-terminal relay discovery response message from the target proximity service terminal, A proximity service relay terminal characterized by a step of transmitting, to the source proximity service terminal, a second terminal-to-terminal relay discovery response message including the identification information capable of identifying the target proximity service terminal corresponding to the source proximity service terminal.

11. In paragraph 9, A proximity service relay terminal, characterized in that the second direct communication request message is transmitted to the target proximity service terminal in unicast.

12. In paragraph 9, the control unit, A proximity service relay terminal characterized in that, when the proximity service relay terminal cannot identify the target proximity service terminal corresponding to the source proximity service terminal based on the identification information, the proximity service relay terminal transmits the third direct communication request message as a broadcast.

13. In a source proximity service terminal of a wireless communication system, Transmitter and receiver; and Connected to the above transmitter and receiver, Transmitting a direct communication request message including identification information that can identify a target proximity service terminal corresponding to the source proximity service terminal to the proximity service relay terminal, Based on the direct communication request transmitted to the target proximity service terminal identified based on the above identification information, a direct communication response message is received from the proximity service relay terminal, A source proximity service terminal including a control unit that performs communication with the target proximity service terminal through the proximity service relay terminal.

14. In the 13th paragraph, the control unit, Transmitting a terminal-to-terminal relay discovery request message to the proximity service relay terminal, A source proximity service terminal characterized in that it receives, from the proximity service relay terminal, a terminal-to-terminal relay discovery response message including the identification information capable of identifying the target proximity service terminal corresponding to the source proximity service terminal.

15. In paragraph 13, A request message according to the above direct communication request message is transmitted unicast from the proximity service relay terminal to the target proximity service terminal, A source proximity service terminal, characterized in that when the proximity service relay terminal cannot identify the target proximity service terminal corresponding to the source proximity service terminal based on the identification information, the request message according to the direct communication request message is transmitted as a broadcast by the proximity service relay terminal.

Images