Method and device for relay discovery in wireless communication system

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting higher data transmission rates. A method performed by a first proximity-based services (ProSe)-enabled user equipment (UE) for providing a ProSe relay function in a wireless communication system according to an embodiment of the present disclosure comprises the steps of: receiving ProSe Discovery model selection information from a network; selecting a ProSe Discovery model on the basis of the ProSe Discovery model selection information; and performing ProSe Discovery on the basis of the selected ProSe Discovery model, wherein the ProSe Discovery model selection information is received for each relay service code (RSC) of a corresponding ProSe service.

Description

Method and device for relay discovery in wireless communication systems

[0001] The present disclosure relates to a method and device for relay discovery in a wireless communication system, and a method and device for searching for a 5G ProSe UE-to-UE Relay in an environment supporting multiple hop relays.

[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 frequency band such as 3.5 gigahertz (3.5GHz), but also in the ultra-high frequency band called millimeter wave (mmWave) such as 28GHz and 39GHz ('Above 6GHz'). 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 an ultra-low latency time 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 enhanced Mobile Broadband (eMBB), Ultra-Reliable Low-Latency Communications (URLLC), and massive Machine-Type Communications (mMTC). These include beamforming and massive MIMO to mitigate 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 subcarrier 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 Code for reliable transmission of control information, and L2 pre-processing (L2). Standardization has been made for network slicing, which provides dedicated networks specialized for specific services, and pre-processing.

[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 (Industrial Internet of Things, IIoT) to support new services through linkage and convergence with other industries, Integrated Access and Backhaul (IAB) that provides 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) that simplifies random access procedures. Standardization is also in progress for system architecture / services such as 5G baseline architecture (e.g., Service-based Architecture, Service-based Interface) 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] Once these 5G mobile communication systems are commercialized, an explosive increase in connected devices will be connected to the communication network, necessitating enhanced functionality and performance of 5G mobile communication systems and integrated operation of these 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 Antenna, and Large Scale Antenna, 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, AI (Artificial Intelligence) from the design stage and AI-based communication technology that realizes system optimization by internalizing end-to-end AI support functions, and ultra-high-performance communication and computing resources to provide services with complexity that exceeds the limits of terminal computing capabilities. It can serve as a basis for the development of next-generation distributed computing technologies that can be realized by utilizing them.

[0008] The disclosed embodiment seeks to provide a method and device capable of effectively providing a service in a wireless communication system.

[0009] The present disclosure proposes a method for determining a method for discovering a 5G ProSe Relay in an environment supporting 5G ProSe UE-To-UE Relay and 5G ProSe UE-To-Network Relay.

[0010] The purpose of the present invention is to provide a method and device for effectively supporting ProSe (Proximity based Services) in a multiple hops environment.

[0011] 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.

[0012] According to one embodiment of the present disclosure, a method of a first ProSe enabled UE (user equipment) providing a ProSe (Proximity based services) Relay function in a wireless communication system includes the steps of: receiving a request message for relay discovery from a second ProSe enabled UE; adjusting at least one parameter included in the request message; and transmitting the request message to a third ProSe enabled UE; wherein the at least one parameter included in the request message includes at least one multi-hop related parameter.

[0013] According to one embodiment of the present disclosure, a method of a second ProSe (Proximity based services) enabled UE (user equipment) in a wireless communication system includes the step of transmitting a request message for relay discovery to a first ProSe enabled UE (user equipment) providing a ProSe Relay function, wherein at least one parameter included in the request message is adjusted, and the request message is transmitted to a third ProSe enabled UE, and the at least one parameter included in the request message includes at least one multi-hop related parameter.

[0014] According to one embodiment of the present disclosure, a first ProSe enabled UE (user equipment) providing a ProSe (Proximity based services) Relay function in a wireless communication system includes a transceiver; and at least one processor; wherein the at least one processor is configured to receive a request message for relay discovery from a second ProSe enabled UE, adjust at least one parameter included in the request message, and transmit the request message to a third ProSe enabled UE, wherein the at least one parameter included in the request message includes at least one multi-hop related parameter.

[0015] According to one embodiment of the present disclosure, in a wireless communication system, a second ProSe (Proximity based services) enabled UE (user equipment) includes a transceiver; and at least one processor; wherein the at least one processor is configured to transmit a request message for relay discovery to a first ProSe enabled UE (user equipment) that provides a ProSe Relay function, wherein at least one parameter included in the request message is adjusted and the request message is transmitted to a third ProSe enabled UE, and wherein the at least one parameter included in the request message includes at least one multi-hop related parameter.

[0016] The present disclosure aims to provide a method and device for effectively supporting ProSe (Proximity based services) in a wireless communication system.

[0017] In connection with one embodiment, a method and device for effectively supporting ProSe in a multiple hops environment are provided. Specifically, an effective method and device for a communication process between UEs via at least one relay are provided.

[0018] 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.

[0019] FIG. 1 is a diagram illustrating the structure of a 5G network according to one embodiment of the present disclosure.

[0020] FIG. 2 illustrates a 5G ProSe (proximity based services) UE-to-UE Relay structure according to one embodiment of the present disclosure.

[0021] FIG. 3 illustrates a 5G ProSe (Proximity based Services) UE-to-Network Relay structure according to one embodiment of the present disclosure.

[0022] FIG. 4 illustrates a model A scheme of 5G ProSe Relay Discovery according to one embodiment of the present disclosure.

[0023] FIG. 5 illustrates a model B scheme of 5G ProSe Relay Discovery according to one embodiment of the present disclosure.

[0024] FIG. 6A and FIG. 6B illustrate a Discovery Model selection procedure of a 5G ProSe Relay providing a 5G ProSe Relay service according to an embodiment of the present disclosure.

[0025] FIG. 7a and FIG. 7b illustrate a Discovery Model selection procedure of a 5G ProSe enabled UE using a G ProSe Relay service according to an embodiment of the present disclosure.

[0026] FIG. 8 is a diagram showing the configuration of a user equipment (UE) according to one embodiment of the present disclosure.

[0027] FIG. 9 is a diagram illustrating a 5G ProSe (proximity based services) UE-to-UE relay structure supporting multiple hops according to one embodiment of the present disclosure.

[0028] FIG. 10 is a diagram illustrating a 5G ProSe UE-to-UE Relay Discovery Model B scheme according to one embodiment of the present disclosure.

[0029] FIG. 11 is a diagram illustrating a 5G ProSe UE-to-UE Relay Discovery Solicitation message transmission process according to one embodiment of the present disclosure.

[0030] FIG. 12 is a diagram illustrating a process in which a Discoveree 5G ProSe End UE transmits a 5G ProSe UE-to-UE Relay Discovery Response message according to one embodiment of the present disclosure.

[0031] FIG. 13 is a diagram illustrating a procedure of a 5G ProSe UE-to-UE Relay Discovery (Model B) method in a Multiple Hops environment according to one embodiment of the present disclosure.

[0032] FIG. 14 is a diagram showing the configuration of a terminal according to one embodiment of the present disclosure.

[0033] FIG. 15 is a diagram illustrating a configuration of a base station or network entity according to one embodiment of the present disclosure.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] The advantages and features of the present disclosure, and methods for achieving them, will become clearer with reference to the embodiments described below in detail 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. These 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.

[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 play one or more processors. Accordingly, 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'. Additionally, components and '~parts' may be implemented to regenerate one or more CPUs within a device or secure multimedia card.

[0041] In this disclosure, phrases such as "A / 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).

[0042] 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 type 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.

[0043] In the following description, terms used to identify connection nodes, terms referring to network entities 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.

[0044] 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.

[0045] FIG. 1 illustrates the structure of a 5G network according to an embodiment of the present disclosure.

[0046] Referring to Figure 1, the network entities or network nodes that constitute the 5G network are described as follows.

[0047] (R)AN ((Radio) Access Network) (100) is an entity that performs wireless 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 (NextGeneration Radio Access Network), a 5G-AN, a wireless access unit, a base station controller, or a node on a network.

[0048] The terminal (105) may include a User Equipment (UE), a Next Generation UE (NG UE), a Mobile Station (MS), a cellular phone, a smartphone, a computer, or a multimedia system capable of performing communication functions. Furthermore, while the embodiments of the present disclosure will be described below using a 5G system as an example, the embodiments of the present disclosure may also be applied to other communication systems with similar technical backgrounds. Furthermore, the embodiments of the present disclosure may 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.

[0049] As wireless communication systems evolve from 4G to 5G, a new core network, NextGen Core (NG 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 (NF) may refer to a network entity, a network component, or a network resource.

[0050] According to one embodiment of the present disclosure, 5GC may include NFs as 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 number of NFs illustrated in FIG. 1.

[0051] An Access and Mobility Management Function (AMF) (110) may be a network function that manages access and mobility of a terminal (UE). For example, AMF may perform network functions such as registration, connection, reachability, mobility management, access verification, authentication, and mobility event generation.

[0052] The SMF (Session Management Function) (115) may be a network function that manages a Packet Data Network (PDN) connection provided to a user equipment (UE). The PDN connection may be referred to as a Packet Data Unit (PDU) Session. For example, the SMF may perform network functions such as session management functions through establishing, modifying, and releasing sessions and maintaining a tunnel between the UPF (131) and the RAN required for this, allocation and management of the IP (Internet protocol) address of the UE, selection and control of the user plane, control of traffic processing in the UPF (120), and control of collection of charging data.

[0053] PCF (Policy Control Function) (125) may be a network function that applies a mobile communication service provider's service policy, charging policy, and policy for PDU Session to a terminal.

[0054] Unified Data Management (UDM) (130) may be a network function that stores subscriber information. For example, UDM (130) may perform functions such as generating authentication information for 3GPP security, processing user identifiers (user IDs), managing a list of network functions supporting UE (105), and managing subscription information.

[0055] The Network Exposure Function (NEF) (135) may be a function that provides information about a terminal to a server outside the 5G network. Furthermore, the NEF may provide the function of storing information necessary for 5G network services in the UDR.

[0056] The UPF (User Plane Function) (120) may be a function that performs the role of a gateway that transmits user data (PDU) to a DN (Data Network). More specifically, the UPF may perform the role of processing data so that data transmitted by a terminal can be transmitted to an external network or data received from an external network can be transmitted to the terminal. For example, the UPF (131) 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 creation, and buffering.

[0057] NRF (Network Repository Function) (140) can perform the function of discovering NF.

[0058] AUSF (Authentication Server Function) (145) can perform terminal authentication in 3GPP access networks and non-3GPP access networks.

[0059] NSSF (Network Slice Selection Function) (150) can perform the function of selecting a Network Slice Instance provided to a terminal.

[0060] DN (Data Network) (155) may be a data network through which terminals transmit and receive data in order to use a network operator's service or a third-party service.

[0061] The Application Function (AF) (160) is a control unit function within or outside the core network that can provide application services to subscribers. For example, it may be for video streaming services. If the AF (160) is trusted, it can interact directly with the core network function, or if it is a third party, it can interact with the Network Equipment Function (NEF) (135).

[0062] SCP (Service Communication Proxy) (165) can provide various functions ranging from simplifying network topology by applying signal aggregation and routing to load balancing, overload handling, message parameter adjustment, and interoperability with legacy systems.

[0063] Additionally, terms used in this disclosure are defined as follows.

[0064] 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, bypassing the core network.

[0065] A ProSe-enabled UE (proximity service-enabled terminal) refers to a UE that supports ProSe discovery and / or ProSe communication.

[0066] ProSe UE-to-Network Relay (Proximity Service UE-to-Network Relay) is a ProSe-enabled UE, and refers to a type of relay that acts as a communication relay between the ProSe-enabled UE and the network.

[0067] ProSe UE-to-UE Relay (Proximity Service UE-to-UE 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.

[0068] 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.

[0069] FIG. 2 illustrates a 5G ProSe (Proximity based Services) UE-to-UE Relay structure according to an embodiment of the present disclosure.

[0070] 5G ProSe End UE (200, 220) and 5G ProSe UE-to-UE Relay (210) are both 5G ProSe enabled UEs, and the 5G ProSe End UE (200, 220) can communicate with the counterpart 5G ProSe End UE (200, 220) using the 5G ProSe UE-to-UE Relay (210). The 5G ProSe UE-to-UE Relay (210) can provide a data relay service to enable the 5G ProSe End UEs (200, 220) to communicate. In addition, the 5G ProSe enabled UEs (5G ProSe End UE (200, 220) and 5G ProSe UE-to-UE Relay (210)) use the PC5 interface to transmit data and / or signaling.

[0071] FIG. 3 illustrates a 5G ProSe (Proximity based Services) UE-to-Network Relay structure according to an embodiment of the present disclosure.

[0072] 5G ProSe Remote UE (300) and 5G ProSe UE-to-Network Relay (310) are both 5G ProSe enabled UEs, and the 5G ProSe Remote UE (300) can communicate with the NG-RAN (network) using the 5G ProSe UE-to-Network Relay (310). In addition, the 5G ProSe UE-to-Network Relay (310) can provide a data relay service so that the 5G ProSe Remote UEs (300) can communicate with the network.

[0073] Additionally, the PC5 interface may be used to transmit data and / or signaling between the 5G ProSe Remote UE (300) and the 5G ProSe UE-to-Network Relay (310), and the Uu interface may be used to transmit data and / or signaling between the 5G ProSe UE-to-Network Relay (310) and the NG-RAN (network).

[0074] FIG. 4 illustrates a model A scheme for 5G ProSe Relay Discovery according to an embodiment of the present disclosure.

[0075] Model A is a model that uses a single discovery protocol message (Announcement) message (430, 440). In Model A, a 5G ProSe Relay (410) includes the relay service it can provide in the form of a Relay Service Code (RSC) in a 5G ProSe Relay Discovery Announcement message (430, 440) and transmits it to surrounding 5G ProSe End UEs (400, 420). The 5G ProSe Relay (410) may include a 5G ProSe UE-To-UE Relay and a 5G ProSe UE-To-Network Relay. The 5G ProSe End UE (400, 420) is a ProSe enabled UE.

[0076] The 5G ProSe End UE (400, 420) that receives the above 5G ProSe Relay Discovery Announcement message (430, 440) can determine the 5G ProSe Relay that provides the relay service to be used based on the RSC and initiate relay communication using the 5G ProSe Relay.

[0077] FIG. 5 illustrates a 5G ProSe Relay Discovery Model B scheme according to an embodiment of the present disclosure.

[0078] Model B uses two discovery protocol messages (Solicitation message and Response message). In Model B, a 5G ProSe End UE (500) transmits a 5G ProSe Relay Discovery Solicitation message (530) to a nearby 5G ProSe Relay (510) (including a 5G ProSe UE-To-UE Relay and a 5G ProSe UE-To-Network Relay) to use the Relay service. This message includes the RSC value of the ProSe service to be used by the 5G ProSe End UE (500).

[0079] The 5G ProSe Relay (510) that receives the 5G ProSe Relay Discovery Solicitation message can confirm whether the 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 (520). Alternatively, the 5G ProSe Relay (510) that receives the 5G ProSe Relay Discovery Solicitation message generates a 5G ProSe Relay Discovery Response message in response to the Solicitation message and transmits the Response message to the 5G ProSe End UE (500) that transmitted the Discovery Solicitation, thereby completing the Relay Discovery procedure. 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) are supported for 5G ProSe Relay Discovery.

[0080] Additionally, a 5G ProSe enabled UE can receive information from the network about the authority to provide or use the 5G ProSe Relay function of each 5G ProSe enabled UE through Authorization and Parameters Provisioning. Each 5G ProSe enabled UE can receive from the network the authority to provide the Relay service as a 5G ProSe UE-to-Network Relay or a 5G ProSe UE-to-UE Relay and / or the authority to use the Relay service.

[0081] Additionally, a 5G ProSe enabled UE may also receive authorization to use Model A and / or Model B for 5G ProSe Relay Discovery. Finally, a validity time for the validity period of the received authorization and / or parameters may also be received.

[0082] The present disclosure proposes a method for 5G ProSe enabled UEs with 5G ProSe Relay and / or 5G ProSe End / Remoted UE authority to select Model A or Model B in a discovery procedure for using a relay service. Each 5G ProSe enabled UE can receive authorization from the network to provide or use the relay service.

[0083] When a 5G ProSe-enabled UE uses a relay service, if there is no criteria for selecting between Model A and Model B during the discovery procedure, the UE providing the relay service and the UE seeking to use the service may continue to wait for a Solicitation message or Announcement message, respectively. Therefore, this disclosure proposes a method for determining which discovery model a UE providing the relay service and a UE using the relay service should select.

[0084] In one embodiment, a 5G ProSe enabled UE may receive parameters for discovery model selection from a PCF or a ProSe Application Server. The parameters are associated with each RSC. That is, the 5G ProSe enabled UE may receive parameters for each RSC. Information for discovery model selection received from a network including the PCF or the ProSe application server may include at least one of the following parameters: - Latency Requirement for Immediate Service

[0085] Additionally, the information for selecting the above Discovery model may further include parameters set per RSC (Per RSC) as follows.

[0086] - Immediate Indication

[0087] - Latency Requirement

[0088] -Discovery Announcement Only Indication

[0089] - Discovery Solicitation Only Indication

[0090] - Incentive for Relay Service

[0091] Additionally, each 5G ProSe enabled UE may additionally consider the following parameters for model selection:

[0092] - Battery Power Status

[0093] - Status of Relay Load

[0094] The Latency Requirement of Immediate Service is a parameter that indicates the time value within which relay service must be provided and used for an RSC with an Immediate Indication. This can primarily apply to emergency services. In other words, in the case of urgent services, relay service must be provided immediately and data must be transmitted using the relay. In this case, the Latency Requirement of Immediate Service indicates the transmission delay required for data transmission.

[0095] The following parameters are provided for each RSC:

[0096] - Immediate Indication is a parameter indicating a service that requires immediate data transmission. In one embodiment, an Emergency RSC for an urgent service may include an Immediate Indication. Furthermore, services in an RSC that includes an Immediate Indication may require a transmission delay that satisfies the Latency Requirement of Immediate Service value.

[0097] - Latency Requirement is a parameter that indicates the transmission delay required for RSC services that do not include Immediate Indication. The service requires a transmission delay that satisfies the Latency Requirement value.

[0098] - Discovery Announcement Only Indication is a parameter that indicates that the service of the RSC is a service that is supported only by Model A.

[0099] - Discovery Solicitation Only Indication is a parameter that indicates that the service of the RSC is a service that is supported only by Model B.

[0100] The "Incentive for Relay Service" parameter indicates the incentive received from the network when relaying the RSC's service. This incentive can be provided in various forms, such as monetary benefits or discounts.

[0101] In addition to the above parameters, the present disclosure may include other parameters for selecting a Discovery model.

[0102] FIGS. 6A and 6B illustrate a Discovery Model selection procedure of a 5G ProSe Relay providing a 5G ProSe Relay service according to an embodiment of the present disclosure.

[0103] In FIGS. 6a and 6b, the 5G ProSe Relay includes a 5G ProSe UE-To-UE Relay and a 5G ProSe UE-To-Network Relay.

[0104] 5G ProSe Relay can perform Discovery Model selection for each RSC.

[0105] The 5G ProSe Relay can check the validity time to verify the validity of the received authorization and / or parameter information (600). If the validity time has expired, the 5G ProSe Relay can request provisioning of the authorization and / or parameter information from the network (605).

[0106] If the validity time has not expired, the 5G ProSe Relay can check the usage rights of Model A and / or Model B based on the Authorization and / or Parameter information received from the network (610). If the 5G ProSe Relay confirms that only Model A or Model B can be used, it can perform Discovery using that model (613, 615).

[0107] If the Authorization or Parameter information received from the network does not include authorization information that requires the use of only Model A or Model B, the 5G ProSe Relay can check whether the information for selecting a Discovery model includes an Immediate Indication (620). If the information for selecting a Discovery model includes an Immediate Indication, the 5G ProSe Relay can immediately transmit an Announcement message to the surroundings at a frequency that corresponds to the Latency Requirement for Immediate Service (625).

[0108] Afterwards, the 5G ProSe Relay can check whether the information for selecting a discovery model includes a Discovery Announcement Only Indication or a Discovery Solicitation Only Indication (630, 640). If the information for selecting a discovery model includes a Discovery Announcement Only Indication, the 5G ProSe Relay can select Model A (635), and if it includes a Discovery Solicitation Only Indication, the 5G ProSe Relay can select Model B (645). The information for selecting a discovery model cannot include both the Discovery Announcement Only Indication and the Discovery Solicitation Only Indication at the same time.

[0109] When the information for selecting a discovery model does not include either Discovery Announcement Only Indication or Discovery Solicitation Only Indication, and thus both Model A and Model B are possible, the 5G ProSe Relay can decide whether to provide a relay service by considering its own battery status, current Relay Service Load status, and / or RSC Incentive (650).

[0110] If the 5G ProSe Relay decides not to actively provide the service (i.e., passively provide it), it selects Model B and waits for a Solicitation message (655). If it decides to actively provide the service, it can set a timer equal to the Latency Requirement (660). Even if Model B is selected by not actively providing the service, if the Latency Requirement Timer expires and no 5G ProSe Relay provides the service, Model A can be selected to provide the relay service after a certain period of time.

[0111] The 5G ProSe Relay can determine whether to receive a Solicitation message before the Timer expires (670). If the 5G ProSe Relay does not receive a Solicitation message before the Timer expires, it can select Model A and transmit an Announcement message to the surroundings (675). In one embodiment, the period at which the 5G ProSe Relay transmits the Announcement message can be set to the Latency Requirement for Immediate Service.

[0112] If a 5G ProSe Relay receives a Solicitation message before the Timer expires, the 5G ProSe Relay can determine whether to provide a relay service based on whether another 5G ProSe Relay nearby relays the Solicitation message (680). That is, the 5G ProSe Relay can determine whether another 5G ProSe Relay nearby relays the Solicitation message (680). That is, the 5G ProSe Relay can monitor whether the same Solicitation message it received is retransmitted by another 5G ProSe Relay nearby.

[0113] If the 5G ProSe Relay determines that there is no other 5G ProSe Relay around it that relays the Solicitation message because it does not receive the same retransmitted Solicitation message, and thus decides to provide a relay service, the 5G ProSe Relay may select Model B to relay the solicitation message around it (685).

[0114] If a 5G ProSe Relay receives the same Solicitation message that has been retransmitted (i.e., relayed) and decides not to provide the relay service because there is another 5G ProSe Relay nearby that relays the Solicitation message, the 5G ProSe Relay may set a NO SERVICE TAG to the RSC (690). In one embodiment, since the 5G ProSe Relay serving the same RSC nearby may move to another location and / or may not be able to provide the service for other reasons, the 5G ProSe Relay may set a Timer to periodically check this.

[0115] FIGS. 7a and 7b illustrate a Discovery Model selection procedure of a 5G ProSe enabled UE using a 5G ProSe Relay service according to an embodiment of the present disclosure.

[0116] 5G ProSe enabled UE can perform Discovery Model selection for each RSC.

[0117] A 5G ProSe enabled UE can check the validity time to check the validity of the received Authorization and / or Parameter information (700).

[0118] If the validity time has expired, the 5G ProSe enabled UE can request provisioning of authorization and / or parameter information to the network (705).

[0119] If the validity time has not expired, the 5G ProSe enabled UE checks whether to use Model A and / or Model B based on the Authorization and / or Parameter information received from the network. If the 5G ProSe enabled UE confirms that only one of the two can be used, it can perform discovery using that model (613, 615).

[0120] If the Authorization or Parameter information received from the network does not include authorization information that requires the use of only one of Model A or Model B, the 5G ProSe enabled UE may check whether the information for selecting a Discovery model includes an Immediate Indication (720). If the information for selecting a Discovery model includes an Immediate Indication, the 5G ProSe enabled UE may transmit a Solicitation message within the Latency Requirement for Immediate Service time (725).

[0121] Thereafter, the 5G ProSe enabled UE can check whether the information for discovery model selection includes the Discovery Announcement Only Indication or the Discovery Solicitation Only Indication (730, 740). If the information for discovery model selection includes the Discovery Announcement Only Indication, the 5G ProSe enabled UE can select Model A (735), and if it includes the Discovery Solicitation Only Indication, the 5G ProSe enabled UE can select Model B (745). The information for discovery model selection may selectively include either the Discovery Announcement Only Indication or the Discovery Solicitation Only Indication, or may not include both the Discovery Announcement Only Indication and the Discovery Solicitation Only Indication. That is, the information for discovery model selection cannot include the Discovery Announcement Only Indication and the Discovery Solicitation Only Indication at the same time.

[0122] When the information for selecting a discovery model does not include both the Discovery Announcement Only Indication and the Discovery Solicitation Only Indication, and thus both Model A and Model B are possible, the 5G ProSe enabled UE can decide whether to actively use the service by considering its battery status, current Relay Service Load status, and RSC Incentive (750). That is, the 5G ProSe enabled UE can decide whether to use Model A or Model B in terms of the discovery model.

[0123] If a 5G ProSe enabled UE decides not to actively use the service (i.e., passively use it), it can select Model A and wait for the Announcement message to be received (745). Furthermore, if the 5G ProSe enabled UE decides to actively use the service, it can set a Timer equal to the Latency Requirement (760). Even if it decides not to actively provide the service and selects Model A, if the Latency Requirement Timer expires and no 5G ProSe enabled UE or 5G ProSe Relay provides the service, it can select Model B and start the service after a certain time.

[0124] If the 5G ProSe enabled UE does not receive an Announcement message before the Timer expires, it may select Model B and transmit a Solicitation message to the surroundings (775). In one embodiment, the period at which the 5G ProSe enabled UE transmits the Solicitation message may be set to the Latency Requirement for Immediate Service.

[0125] A 5G ProSe enabled UE can use the Relay service using Model A if it receives the Announcement message before the Timer expires (780).

[0126] FIG. 7 illustrates a flowchart for the operation of a 5G ProSe enabled UE according to an embodiment of the present disclosure.

[0127] The 5G ProSe enabled UE of FIG. 7 may include a ProSe enabled UE that provides or uses a ProSe Relay service.

[0128] In one embodiment, a ProSe enabled UE may receive ProSe Discovery model selection information from a network (810). The ProSe enabled UE may select a ProSe Discovery model based on the ProSe Discovery model selection information (820). The ProSe enabled UE may perform ProSe Discovery based on the selected ProSe Discovery model (830). The ProSe Discovery model selection information is characterized in that it is received for each RSC (relay service code) of the corresponding ProSe service.

[0129] Below, an embodiment is described in which the ProSe enabled UE is a relay providing ProSe Relay service.

[0130] In one embodiment, when the ProSe Discovery model selection information includes an Immediate indication, the selected ProSe Discovery model may be a first model that transmits an Announcement message to at least one second ProSe enabled UE.

[0131] In one embodiment, if the ProSe Discovery model selection information does not include an Immediate indication and the ProSe Discovery model selection information includes a Discovery Announcement Only Indication, the selected ProSe Discovery model may be the first model.

[0132] In one embodiment, when the ProSe Discovery model selection information does not include an Immediate indication and the ProSe Discovery model selection information includes a Discovery Solicitation Only Indication, the selected ProSe Discovery model may be a second model that waits for reception of a Solicitation message from the at least one second ProSe enabled UE and, when a Solicitation message is received, transmits a response message to the at least one second ProSe enabled UE.

[0133] In one embodiment, the operation of selecting the ProSe Discovery model may further include an operation of selecting the ProSe Discovery model based on at least one of battery status information, relay load information, and incentive information of a relay service included in the ProSe Discovery model selection information, when the ProSe Discovery model selection information does not include the Immediate indication, the Discovery Announcement Only Indication, and the Discovery Solicitation Only Indication.

[0134] In one embodiment, the operation of selecting a ProSe Discovery model based on at least one of the battery status information, the relay load information, and incentive information of the Relay Service included in the ProSe Discovery model selection information includes the operation of setting a timer corresponding to a Latency Requirement received from a network, and when a Solicitation message is not received until the set timer expires, the selected ProSe Discovery model may be the first model.

[0135] In one embodiment, the operation of selecting the ProSe Discovery model may further include an operation of determining whether to provide a relay service based on whether the received Solicitation message is received from at least one third ProSe enabled UE that provides a relay service when a Solicitation message is received before the set timer expires; and, when the Solicitation message is received from the third terminal, the operation of setting a tag indicating that the relay service is not provided to the corresponding RSC may further include an operation of setting the tag.

[0136] Below, an embodiment is described in which the ProSe enabled UE is a relay that uses the ProSe Relay service.

[0137] In one embodiment, when the ProSe Discovery model selection information includes an Immediate indication, the selected ProSe Discovery model may be a first model that transmits a Solicitation message to at least one second ProSe enabled UE and receives a Response message from the at least one second ProSe enabled UE.

[0138] In one embodiment, the operation of selecting the ProSe Discovery model may further include an operation of selecting the ProSe Discovery model based on at least one of battery status information, relay load information, and incentive information of a relay service included in the ProSe Discovery model selection information, if the ProSe Discovery model selection information does not include an Immediate indication, a Discovery Announcement Only Indication, or a Discovery Solicitation Only Indication.

[0139] In one embodiment, the operation of selecting a ProSe Discovery model based on at least one of the battery status information, the relay load information, and incentive information of the Relay Service included in the ProSe Discovery model selection information includes the operation of setting a timer corresponding to a Latency Requirement received from a network, and when an Announcement message is not received until the set timer expires, the selected ProSe Discovery model may be the first model.

[0140] Figure 9 illustrates a 5G ProSe (Proximity based Services) UE-to-UE Relay structure supporting multiple hops.

[0141] According to one embodiment, both the 5G ProSe End UE (900, 920) and the 5G ProSe UE-to-UE Relay (910, 915) are 5G ProSe enabled UEs, and the 5G ProSe End UE (900, 920) can communicate with the counterpart 5G ProSe End UE using the 5G ProSe UE-to-UE Relay (910, 915), and the 5G ProSe UE-to-UE Relay (910, 915) can provide a data relay service to enable the 5G ProSe End UEs (900, 920) to communicate. In addition, the 5G ProSe enabled UEs can use an interface (e.g., a PC5 interface) for communication between UEs to transmit data and signaling.

[0142] The above 5G ProSe enabled UE may correspond to a UE capable of supporting 5G ProSe requirements and related communication processes.

[0143] FIG. 9 illustrates a structure that supports multiple hops, in which one or more 5G ProSe UE-to-UE Relays (910, 915) can be used for data transmission. Specifically, as shown in FIG. 9, a 5G ProSe End UE can be exemplified as a multiple hops structure that uses two 5G ProSe UE-to-UE Relays to communicate with a counterpart 5G ProSe End UE, and can be described as a structure that communicates using three exemplified PC5 interfaces.

[0144] Figure 10 illustrates a 5G ProSe UE-to-UE Relay Discovery Model B scheme.

[0145] UE-to-UE Relay Discovery can use Model A and Model B discovery methods.

[0146] Model A defines the roles of ProSe-enabled UEs as announcing UEs and monitoring UEs. The announcing UE announces information that can be used by nearby UEs that allow discovery, while the monitoring UE receives information from the announcing UE. The announcing UE broadcasts discovery messages according to a preset discovery cycle, and the monitoring UE reads and processes them.

[0147] Model B defines the roles of UEs, namely, Discoverer UE and Discoveree UE. The Discoverer UE requests information necessary for discovery, while the Discoveree UE receives Discover requests and responds with information related to the Discover request.

[0148] For example, in FIG. 10, which can be exemplified by Model B, a 5G ProSe End UE (1000) may correspond to a Discoverer UE, and a counterpart 5G ProSe End UE (1020) via a 5G ProSe UE-to-UE Relay (1010) may correspond to a Discoveree UE.

[0149] FIG. 10 illustrates a Model B scheme in which a 5G ProSe End UE (1000) transmits a message for Discover (e.g., Discovery Solicitation message) (1030, 1040) through a 5G ProSe UE-to-UE Relay to Discover a single 5G ProSe UE-to-UE Relay (1010).

[0150] The 5G ProSe UE-to-UE Relay Discovery Solicitation message (1030, 1040) exemplified above may include a Type of Discovery Message, its own User Info ID, RSC (Relay Service Code), the other party's User Info ID, etc.

[0151] The Type of Discovery Message indicates the type of message being transmitted. The User Info ID is a value configured in the 5G ProSe End UE and 5G ProSe UE-to-UE Relay for 5G ProSe UE-to-UE Relay Discovery. The RSC can identify the connectivity service provided by the 5G ProSe UE-to-UE Relay.

[0152] The 5G ProSe UE-to-UE Relay (1010) that receives the Discovery Solicitation message transmitted by the 5G ProSe End UE (1000) can check the RSC included in the message to confirm whether it is a connectivity service provided by itself and then relay it again.

[0153] The counterpart 5G ProSe End UE (1020) that receives the Discovery Solicitation message (1030) transmitted by the 5G ProSe End UE (1000) relayed by the 5G ProSe UE-to-UE Relay (1010) checks the RSC and the counterpart User Info ID included in the received message, and if the message transmitted to itself is correct, it can generate and transmit a response message for the message for Discover (e.g., a 5G ProSe UE-to-UE Relay Discovery Response message).

[0154] One embodiment of the present disclosure proposes a method and device for 5G ProSe UE-to-UE Relay Discovery (Model B) in a Multiple Hops environment for a 5G ProSe End UE to communicate using one or more 5G ProSe UE-to-UE Relays in an environment where Multiple Hops are supported.

[0155] FIG. 11 illustrates a Solicitation message transmission process of a 5G ProSe UE-to-UE Relay Discovery (Model B) method in a Multiple Hops environment according to one embodiment.

[0156] Figure 11 illustrates paths 1, 2, and 3 through which a 5G ProSe End UE (1100) corresponding to a Discoverer communicates with a 5G ProSe End UE (1120) corresponding to a counterpart Discoveree.

[0157] An embodiment related to the above Model B may define a 5G ProSe End UE that initiates a 5G ProSe UE-to-UE Relay search as a Discoverer 5G ProSe End UE. The counterpart UE of the Discoverer may be defined as a Discoveree 5G ProSe End UE.

[0158] A 5G ProSe UE-to-UE Relay Discovery Solicitation message in a multiple hops environment may include at least one parameter.

[0159] In a multiple-hop environment, the 5G ProSe UE-to-UE Relay Discovery Solicitation message may include a 5G ProSe UE-to-UE Relay Discovery parameter group. Parameters for multiple hops may be defined as the Multiple PC5 hops parameter group. The above definition is only an example; other names may be used, and existing and additional parameters may not be distinguished separately.

[0160] The 5G ProSe UE-to-UE Relay Discovery Solicitation message may include Type of Discovery Message, RSC, User Info ID (discoverer), User Info ID (discoveree), and IDs of data senders and receivers (e.g., Source Layer-2 ID, Destination Layer-2 ID).

[0161] A 5G ProSe UE-to-UE Relay Discovery Solicitation message in a multiple hops environment may include at least one of the following information: Hop Limits, Hop Counts, Degree of Mobility, Status of Battery, Status of Load, and Original Source Layer-2 ID.

[0162] The number of hops that a relayed message can be transmitted can be limited by a value that limits the number of hops (e.g., the Hop Limits value). This prevents messages from being relayed throughout the network, causing network congestion. Also, since the distance to an appropriate Discoveree 5G ProSe End UE may vary for each RSC, i.e., service, the Hop Limits value can be adjusted to search for an appropriate Discoveree 5G ProSe End UE.

[0163] For example, FIG. 11 discloses that the Hop Limits value is set to “5” for the Discoverer 5G ProSe End UE.

[0164] For example, path 3 in FIG. 11 initiates a process in which the Discoverer 5G ProSe End UE relays through 5 hops and is limited by the Hop Limits value, so it cannot be relayed to the Discoveree 5G ProSe End UE.

[0165] In one embodiment, the Hop Limits value may be determined based on the ProSe Application Server and network policy, but may also be manually determined based on field conditions (e.g., based on input from an authorized user) and this value may take precedence over the values ​​determined by the ProSe Application Server and network policy. The Hop Limits value may be assigned a different value depending on the RSC and field conditions.

[0166] For example, a service used in a minor disaster situation, such as a traffic accident, may have a small Hop Limits value. However, a disaster that occurs over a large area, such as an earthquake, may have a large Hop Limits value. For example, a disaster area with a small, low-density device population, such as an island, may have a small Hop Limits value. A large, high-density device population, such as a large city, may have a larger Hop Limits value.

[0167] In one embodiment, the Discoverer 5G ProSe End UE (1100) transmits the first 5G ProSe UE-to-UE Relay Discovery Solicitation message using a value greater than the Min. value of Hop Limits to avoid network congestion, but if the 5G ProSe UE-to-UE Relay Discovery Response message is not received for a specified time (Timer), the value may be set between the Min. value and the Max. value or to the Max. value and retransmitted, depending on the RSC and disaster site situation.

[0168] Additionally, depending on the on-site situation (disaster type, area size, urgency, etc.), the value may be set to a value greater than the Max. value based on Manual and retransmitted. For example, the Discoverer 5G ProSe End UE (1100) may retransmit the 5G ProSe UE-to-UE Relay Discovery Solicitation message based on input from an authorized user, depending on the on-site situation (disaster type, area size, urgency, etc.).

[0169] For example, the Hop limits value can be automatically adjusted by a specific algorithm set according to the field situation exemplified above, or can be set to a manually adjusted value (for example, can be set based on the input of an authorized user). In one embodiment, a value indicating the number of hops (for example, Hop Counts) can be a value that increases with each hop, and can indicate how many hops the Solicitation message has traveled to arrive at the Discoveree 5G ProSe End UE. This value can be used as a basis for determining which path-on message to select when the Discoveree 5G ProSe End UE receives a Solicitation message transmitted through multiple paths in the future.

[0170] In one embodiment, a value indicating the degree of mobility of the Relay (e.g., Degree of Mobility), a value indicating the available battery capacity of the Relay (e.g., Status of Battery), and a value indicating the load of the Relay connectivity service (e.g., Status of Load) are values ​​input by the 5G ProSe UE-to-UE Relay and can be used to select a more stable overall path when selecting a Relay path between the Discoverer 5G ProSe End UE and the Discoveree 5G ProSe End UE.

[0171] Degree of Mobility can be a value indicating the relay's mobility level, i.e., how mobile the relay is. Status of Battery can indicate the relay's available battery capacity.

[0172] In one embodiment, the Relay may correspond to a mobile device and may be powered by a battery, in which case a value representing the battery capacity may be used.

[0173] Status of Load can indicate the load of the Relay Connectivity Service that the Relay is processing.

[0174] In one embodiment, since each Relay has a different location and the types and number of connectivity services it can support, the load it processes may vary. The values ​​exemplified above can be used as basis for determining which path-on message to use when the discoveree 5G ProSe End UE receives a Solicitation message delivered via multiple paths.

[0175] For example, in a path comprised of highly mobile Relays, frequent Relay reselection may occur due to the movement of the Relays. Furthermore, in a path comprised of Relays with low battery capacity, the power of the Relays may be turned off, necessitating Relay reselection. In addition to the parameters that can be used as basis information for the decision exemplified above, other parameters may be added, and are not limited to the parameters exemplified above.

[0176] The Original Source Layer-2 ID value exemplified above can be used to prevent Relays from repeatedly relaying Solicitation messages sent by the same Discoverer. This value may correspond to the value assigned to the Source Layer-2 ID within the 5G ProSe UE-to-UE Relay Discovery parameter group by the Relay that first received the Solicitation message from the Discoverer, i.e., the Source Layer-2 ID value of the Discoverer. Subsequent Relays can relay without changing this value.

[0177] Figure 11 illustrates a 5G ProSe UE-to-UE Relay Discovery Solicitation message transmission process.

[0178] As an example, a Discoverer UE (1100) may generate and transmit a 5G ProSe UE-to-UE Relay Discovery Solicitation message (1130) to communicate with a Discoveree UE (1120) using one or more 5G ProSe UE-to-UE Relays.

[0179] As an example, the 5G ProSe UE-to-UE Relay Discovery parameter group parameter values ​​in the 5G ProSe UE-to-UE Relay Discovery Solicitation message (1130) may be set as follows.

[0180] - Type of Discovery Message: 5G ProSe UE-to-UE Relay Discovery Solicitation

[0181] - User Info ID: User Info ID of discoverer

[0182] - User Info ID: User Info ID of discoveree

[0183] - RSC

[0184] - Source Layer-2 ID: assigned by discoverer

[0185] - Destination Layer-2 ID: default destination Layer-2 ID

[0186] The Multiple PC5 hops parameter group parameter values ​​in the 5G ProSe UE-to-UE Relay Discovery Solicitation message can be set as follows.

[0187] - Hop Limits: Value based on the parameter description above ("5" in Figure 11)

[0188] - Hop Counts: 0

[0189] - Degree of Mobility: Relay only (End UE setting is not excluded)

[0190] - Battery Status: Relay only (end UE setting is not excluded)

[0191] - Status of Load: Relay only (End UE setting is not excluded)

[0192] - Original Source Layer-2 ID: Set only Relay

[0193] In one embodiment, a Solicitation message transmitted by a Discoverer UE may be received by one or more Relays located nearby.

[0194] In one embodiment, if the Destination Layer-2 ID of a message is set to default, all relays can receive the message. In this case, the RSC value within the message can be checked after reception.

[0195] In one embodiment, if the Relay is an RSC providing connectivity services, the Relay may modify and retransmit the received 5G ProSe UE-to-UE Relay Discovery Solicitation message.

[0196] If you have a Discoverer and a one (1) hop Relay, you can modify the message as follows:

[0197] 5G ProSe UE-to-UE Relay Discovery Parameter Group Parameters

[0198] - Type of Discovery Message: 5G ProSe UE-to-UE Relay Discovery Solicitation

[0199] - User Info ID: User Info ID of discoverer

[0200] - User Info ID: User Info ID of discoveree

[0201] - User Info ID: User Info ID of Relay

[0202] - RSC

[0203] - Source Layer-2 ID: assigned by Relay

[0204] - Destination Layer-2 ID: default destination Layer-2 ID

[0205] Multiple PC5 hops parameter group parameters

[0206] - Hop Limits: Received Hop Limits - 1

[0207] - Hop Counts: Received Hop Counts + 1

[0208] - Degree of Mobility: Degree of Mobility of Relay

[0209] - Status of Battery: Status of Battery of Relay

[0210] - Status of Load: Status of Load of Relay

[0211] - Original Source Layer-2 ID: Source Layer-2 ID of Discoverer

[0212] If the relay is more than two (2) hops from the Discoverer, the message can be modified as follows:

[0213] 5G ProSe UE-to-UE Relay Discovery Parameter Group Parameters

[0214] - Type of Discovery Message: 5G ProSe UE-to-UE Relay Discovery Solicitation

[0215] - User Info ID: User Info ID of discoverer

[0216] - User Info ID: User Info ID of discoveree

[0217] - User Info ID: User Info ID of Relay

[0218] - RSC

[0219] - Source Layer-2 ID: assigned by Relay

[0220] - Destination Layer-2 ID: default destination Layer-2 ID

[0221] Multiple PC5 hops parameter group parameters

[0222] - Hop Limits: Received Hop Limits - 1

[0223] - Hop Counts: Received Hop Counts + 1

[0224] - Degree of Mobility: Existing List of Degree of Mobility of Relay, own Degree of Mobility of Relay

[0225] - Status of Battery: Existing List of Status of Battery of Relay, own Status of Battery of Relay

[0226] - Status of Load: Existing List of Status of Load of Relay, own Status of Load of Relay

[0227] - Original Source Layer-2 ID: Source Layer-2 ID of Discoverer (no change)

[0228] In one embodiment, a Relay that receives a Solicitation message including an Original Source Layer-2 ID may determine a duplicated message based on the Discoverer User Info ID, RSC, and Original Source Layer-2 ID values ​​and may not retransmit additional duplicated messages. At this time, the Relay may immediately retransmit the received message and discard all duplicated messages thereafter, or may select duplicated messages among the messages received over a certain period of time by considering Hop Counts, Relay's mobility, battery, and load conditions, or may select the message by considering the received signal strength.

[0229] For example, in Fig. 11, the first received message can be retransmitted in the order of the arrival time of the message, and the duplicated message that arrives later can be discarded.

[0230] Figure 11 illustrates that when a message is retransmitted via Route 3, the Hop Limits value at the last Relay becomes 0, preventing further retransmission. Accordingly, the Discoveree 5G ProSe End UE (1120) can receive two Solicitation messages via Routes 1 and 2.

[0231] The structure of all messages in FIG. 11 can be exemplified by the message of path 1, and the structures of the messages of paths 2 and 3 are omitted or expressed briefly for convenience of explanation, but the specific structure thereof will be clearly understood by those skilled in the art by referring to the detailed description of the present invention.

[0232] In one embodiment, a Discoveree 5G ProSe End UE (1120) that receives a message through two paths can check the RSC value and User Info ID (Discoveree) value in the message.

[0233] In one embodiment, the values ​​of the Solicitation message may be referenced to determine the communication path with the Discoverer UE (1120) among the confirmed messages. Specifically, values ​​such as Hop Counts, Degree of Mobility, Status of Battery, and Status of Load may be referenced. Furthermore, the wireless status of the last hop relay in the order of message arrival may also be considered.

[0234] In the example related to Fig. 11, route 2 with the shortest Hop Counts can be selected based on the Hop Counts value.

[0235] Figure 12 illustrates a process in which a Discoveree 5G ProSe End UE transmits a 5G ProSe UE-to-UE Relay Discovery Response message.

[0236] A Discoveree UE (1220) that selects one of the Solicitation messages received in FIG. 11 can generate a Response message (1230) in response to the message and send it to the Discoverer UE (1200) via Relay. The 5G ProSe UE-to-UE Relay Discovery Response message (1230) can include the following information.

[0237] 5G ProSe UE-to-UE Relay Discovery Parameter Group Parameters

[0238] - Type of Discovery Message: 5G ProSe UE-to-UE Relay Discovery Response

[0239] - User Info ID: User Info ID of discoverer

[0240] - User Info ID: User Info ID of discoveree

[0241] - RSC

[0242] - Source Layer-2 ID: assigned by Discoveree

[0243] - Destination Lyaer-2 ID: source Layer-2 ID in received Solicitation msg

[0244] Multiple PC5 hops parameter group parameters

[0245] - Hop Limits: Hop Counts of received Solicitation msg + 1

[0246] - Hop Counts: 0

[0247] A relay that receives a 5G ProSe UE-to-UE Relay Discovery Response message can modify and retransmit a 5G ProSe UE-to-UE Relay Discovery Response message (1230) including the following information.

[0248] 5G ProSe UE-to-UE Relay Discovery Parameter Group Parameters

[0249] - Type of Discovery Message: 5G ProSe UE-to-UE Relay Discovery Response

[0250] - User Info ID: User Info ID of discoveree

[0251] - User Info ID: User Info ID of Relay

[0252] - RSC

[0253] - Source Layer-2 ID: assigned by Relay

[0254] - Destination Lyaer-2 ID: source Layer-2 ID in received Solicitation msg

[0255] Multiple PC5 hops parameter group parameters

[0256] - Hop Limits: Received Hop Limits - 1

[0257] - Hop Counts: Received Hop Counts + 1

[0258] Figure 13 illustrates the procedure of a 5G ProSe UE-to-UE Relay Discovery (Model B) method in a Multiple Hops environment.

[0259] The above procedure may be related to the contents disclosed in FIGS. 11 and 12.

[0260] Referring to FIG. 13, 5G ProSe End UE-1 (discoverer) (1300) can transmit a UE-to-UE Relay Discovery Solicitation message to 5G ProSe End UE-2 (discoveree) (1320) through 5G ProSe UE-to-UE Relays (1311, 1312, 1313, and 1314).

[0261] In step 1330, the 5G ProSe End UE-1 (1300), exemplified by the discoverer defined in Model B, can transmit a message (exemplified as a UE-to-UE Relay Discovery Solicitation message in FIG. 13) to discover a 5G ProSe UE-to-UE Relay.

[0262] According to the above transmission, the message may be received by 5G ProSe UE-to-UE Relay-1 (1311) and / or 5G ProSe UE-to-UE Relay-2 (1312) at step 1330.

[0263] The 5G ProSe UE-to-UE Relay Discovery Solicitation message exemplified above may be composed of the 5G ProSe UE-to-UE Relay Discovery parameter group parameter values ​​exemplified above and the Multiple PC5 hops parameter group parameter values. For example, the Solicitation message may include at least one of the Type of Discovery Message, its own User Info ID, RSC, and the other party's User Info ID.

[0264] At step 1335, each 5G ProSe UE-to-UE Relay (1311, 1312) can check the RSC value in the message transmitted by 5G ProSe End UE-1 (1300) at step 1330 after receiving the message. If the Relay is an RSC providing connectivity service, the Relay can modify and retransmit the 5G ProSe UE-to-UE Relay Discovery Solicitation message received at step 1330.

[0265] Modifications to the above message may correspond to modifications exemplified above in relation to FIG. 11.

[0266] For example, this may correspond to modifications to the 5G ProSe UE-to-UE Relay Discovery parameter group parameters and / or the Multiple PC5 hops parameter group parameters.

[0267] For example, a Relay receiving a message may modify the Hop Limits value by applying -1 to the received Hop Limits value, modify the Hop Counts value by applying +1 to the received Hop Counts value, and modify it by adding at least one of its Degree of Mobility value, Status of Battery value, or Status of Load value.

[0268] Step 1335 illustrates a process in which 5G ProSe UE-to-UE Relay-1 (1311) and / or Relay-2 (1312) transmits a modified message to Relay-3 (1313).

[0269] At step 1340, 5G ProSe UE-to-UE Relay-3 (1313), which receives messages from 5G ProSe UE-to-UE Relay-1 (1311) and Relay-2 (1312), can discard one message by determining whether it is a duplicate message based on the ID values ​​or service codes of the sender and receiver, such as Discoverer User Info ID, RSC, Original Source Layer-2 ID values, etc.

[0270] Alternatively, you can select it by considering Hop Counts, Relay mobility, battery, load status, etc. without discarding, or by considering the received signal strength.

[0271] In step 1340, 5G ProSe UE-to-UE Relay-3 (1313), which has received messages from 5G ProSe UE-to-UE Relay-1 (1311) and Relay-2 (1312), discards duplicated messages (e.g., duplicated messages) without retransmitting the message received from Relay-2, which is exemplified by the duplicated message. In addition, in step 1345, it is exemplified that the message received from Relay-1, which is selected without being discarded, is modified using the method exemplified above and retransmitted to Relay-4.

[0272] At step 1350, the 5G ProSe UE-to-UE Relay-4 (1314) may modify the message received at step 1335 using the method exemplified above and transmit it to the 5G ProSe End UE-2 (1320) exemplified as the Discoveree.

[0273] In step 1355, 5G ProSe End UE-2 (1320), exemplified as a Discoveree in Model B, can check the RSC and User Info ID included in the message received in step 1350 and then generate a response message (exemplified as a UE-to-UE Relay Discovery Response message in FIG. 13) and transmit it to 5G ProSe UE-to-UE Relay-4 (1314).

[0274] The UE-to-UE Relay Discovery Response message illustrated above may be composed of the 5G ProSe UE-to-UE Relay Discovery parameter group parameter values ​​illustrated above and the Multiple PC5 hops parameter group parameter values.

[0275] At step 1360, the 5G ProSe UE-to-UE Relay-4 (1314) may modify the response message received at step 1355 and transmit it to the 5G ProSe UE-to-UE Relay-3 (1313).

[0276] Modification of the above response message may correspond to the modification exemplified above in relation to FIG. 12.

[0277] For example, this may correspond to modifications to the 5G ProSe UE-to-UE Relay Discovery parameter group parameters and / or the Multiple PC5 hops parameter group parameters.

[0278] For example, a Relay that receives a message can modify the Hop Limits value by applying -1 to the received Hop Limits value, and can modify the Hop Counts value by applying +1 to the received Hop Counts value.

[0279] At step 1365, 5G ProSe UE-to-UE Relay-3 (1313) may modify the message received at step 1360 using the method exemplified above and transmit it to 5G ProSe UE-to-UE Relay-1 (1311).

[0280] In this case, messages may not be transmitted to 5G ProSe UE-to-UE Relay-2 (1312).

[0281] At step 1370, the 5G ProSe UE-to-UE Relay-1 (1311) may modify the message received at step 1365 using the method exemplified above and transmit it to the 5G ProSe End UE-1 (1300).

[0282] FIG. 14 is a diagram illustrating a configuration of a user equipment (UE) according to an embodiment of the present disclosure. The UE according to an embodiment of the present disclosure may include a 5G ProSe Relay or a 5G ProSe enabled UE in the above-described embodiment.

[0283] A terminal according to one embodiment of the present disclosure may include a processor (1420) that controls the overall operation of the terminal, a transceiver (1400) including a transmitter and a receiver, and a memory (1410). 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. 8.

[0284] According to one embodiment of the present disclosure, the transceiver (1400) 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 (1400) can receive signals via a wireless channel, output them to the processor (1420), and transmit the signals output from the processor (1420) via the wireless channel.

[0285] According to one embodiment of the present disclosure, the processor (1420) can control the terminal to perform any one of the operations described above. Meanwhile, the processor (1420), the memory (1410), and the transceiver (1400) 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 (1420) and the transceiver (1400) can be electrically connected. In addition, the processor (1420) can be an Application Processor (AP), a Communication Processor (CP), a circuit, an application-specific circuit, or at least one processor.

[0286] According to one embodiment of the present disclosure, the memory (1410) can store data such as basic programs, application programs, and setting information for the operation of the terminal. In particular, the memory (1410) provides the stored data upon request of the processor (1420). The memory (1410) 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 (1410). In addition, the processor (1420) can perform the above-described embodiments based on a program for performing the above-described embodiments of the present disclosure stored in the memory (1410).

[0287] If the terminal is a ProSe enabled UE providing 5G ProSe Relay, the at least one processor may receive ProSe Discovery model selection information from a network. The at least one processor may select a ProSe Discovery model based on the ProSe Discovery model selection information. The at least one processor may be configured to perform ProSe Discovery based on the selected ProSe Discovery model. The ProSe Discovery model selection information may be received for each RSC (relay service code) of a corresponding ProSe service. In one embodiment, if the ProSe Discovery model selection information includes an Immediate indication, the selected ProSe Discovery model may be a first model that transmits an Announcement message to at least one second ProSe enabled UE.

[0288] In one embodiment, when the ProSe Discovery model selection information does not include an Immediate indication and the ProSe Discovery model selection information includes a Discovery Announcement Only Indication, the selected ProSe Discovery model may be the first model. In one embodiment, when the ProSe Discovery model selection information does not include an Immediate indication and the ProSe Discovery model selection information includes a Discovery Solicitation Only Indication, the selected ProSe Discovery model may be a second model that waits for reception of a Solicitation message from the at least one second ProSe enabled UE and, when a Solicitation message is received, transmits a response message to the at least one second ProSe enabled UE.

[0289] In one embodiment, the at least one processor may be further configured to select the ProSe Discovery model based on at least one of battery status information, relay load information, and incentive information of a Relay Service included in the ProSe Discovery model selection information, if the ProSe Discovery model selection information does not include the Immediate indication, the Discovery Announcement Only Indication, or the Discovery Solicitation Only Indication.

[0290] In one embodiment, the at least one processor is further configured to set a timer corresponding to a Latency Requirement received from a network, and if a Solicitation message is not received until the set timer expires, the selected ProSe Discovery model may be the first model.

[0291] In one embodiment, the at least one processor may be further configured to determine whether to provide a relay service based on whether the received Solicitation message is received from at least one third ProSe enabled UE providing a relay service, if the Solicitation message is received before the set timer expires. In one embodiment, the at least one processor may further include an operation of setting a tag indicating that the relay service is not provided to a corresponding RSC, if the Solicitation message is received from the third terminal.

[0292] If the terminal is a ProSe enabled UE using 5G ProSe Relay, the at least one processor may control receiving ProSe Discovery model selection information from a network. The at least one processor may select a ProSe Discovery model based on the ProSe Discovery model selection information. The at least one processor may perform ProSe Discovery based on the selected ProSe Discovery model. In one embodiment, the ProSe Discovery model selection information may be received for each RSC (relay service code) of a corresponding ProSe service.

[0293] In one embodiment, when the ProSe Discovery model selection information includes an Immediate indication, the selected ProSe Discovery model may be a first model that transmits a Solicitation message to at least one second ProSe enabled UE and receives a Response message from the at least one second ProSe enabled UE.

[0294] In one embodiment, the at least one processor may be further configured to select the ProSe Discovery model based on at least one of battery status information, relay load information, and incentive information of a Relay Service included in the ProSe Discovery model selection information, if the ProSe Discovery model selection information does not include an Immediate indication, a Discovery Announcement Only Indication, or a Discovery Solicitation Only Indication.

[0295] In one embodiment, when the ProSe Discovery model selection information includes an Immediate indication, the selected ProSe Discovery model may be a first model that transmits a Solicitation message to at least one second ProSe enabled UE and receives a Response message from the at least one second ProSe enabled UE.

[0296] In one embodiment, the at least one processor may be further configured to select the ProSe Discovery model based on at least one of battery status information, relay load information, and incentive information of a Relay Service included in the ProSe Discovery model selection information, if the ProSe Discovery model selection information does not include an Immediate indication, a Discovery Announcement Only Indication, or a Discovery Solicitation Only Indication.

[0297] In one embodiment, the at least one processor is further configured to set a timer corresponding to a Latency Requirement received from a network, and if an Announcement message is not received until the set timer expires, the selected ProSe Discovery model may be the first model.

[0298] According to one embodiment of the present disclosure, a method of a first ProSe enabled UE (user equipment) providing a ProSe (Proximity based services) Relay function in a wireless communication system includes: receiving ProSe Discovery model selection information from a network; selecting a ProSe Discovery model based on the ProSe Discovery model selection information; and performing ProSe Discovery based on the selected ProSe Discovery model; wherein the ProSe Discovery model selection information is received for each RSC (relay service code) of a corresponding ProSe service.

[0299] According to one embodiment of the present disclosure, a method of a first ProSe enabled UE (user equipment) using a ProSe (Proximity based services) Relay function in a wireless communication system includes: receiving ProSe Discovery model selection information from a network; selecting a ProSe Discovery model based on the ProSe Discovery model selection information; and performing ProSe Discovery based on the selected ProSe Discovery model; wherein the ProSe Discovery model selection information is received for each RSC (relay service code) of a corresponding ProSe service.

[0300] According to one embodiment of the present disclosure, a first ProSe enabled UE (user equipment) providing a ProSe (Proximity based services) Relay function in a wireless communication system includes a transceiver; and at least one processor; wherein the at least one processor is configured to receive ProSe Discovery model selection information from a network, select a ProSe Discovery model based on the ProSe Discovery model selection information, and perform ProSe Discovery based on the selected ProSe Discovery model, wherein the ProSe Discovery model selection information is received for each RSC (relay service code) of a corresponding ProSe service.

[0301] According to one embodiment of the present disclosure, a first ProSe enabled UE (user equipment) using a ProSe (Proximity based services) Relay function in a wireless communication system includes a transceiver; and at least one processor; wherein the at least one processor is configured to receive ProSe Discovery model selection information from a network, select a ProSe Discovery model based on the ProSe Discovery model selection information, and perform ProSe Discovery based on the selected ProSe Discovery model, wherein the ProSe Discovery model selection information is received for each RSC (relay service code) of a corresponding ProSe service.

[0302] FIG. 15 is a diagram illustrating a configuration of a base station or network entity according to an embodiment of the present disclosure.

[0303] A network entity according to one embodiment of the present disclosure may include a processor (1520) that controls the overall operation of the network entity, a transceiver (1500) including a transmitter and a receiver, and a memory (1510). Of course, the present invention is not limited to the above example, and the network entity may include more or fewer components than those illustrated in FIG. 15.

[0304] According to one embodiment of the present disclosure, the transceiver (1500) 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.

[0305] According to one embodiment of the present disclosure, the processor (1520) can control a network entity to perform any one of the operations described above. Meanwhile, the processor (1520), the memory (1510), and the transceiver (1500) 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 (1520) and the transceiver (1500) can be electrically connected. In addition, the processor (1520) can be an Application Processor (AP), a Communication Processor (CP), a circuit, an application-specific circuit, or at least one processor.

[0306] According to one embodiment of the present disclosure, the memory (1510) may store data such as basic programs, application programs, and setting information for the operation of a network entity. In particular, the memory (1510) provides the stored data upon request of the processor (1520). The memory (1510) 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 (1510). In addition, the processor (1520) may perform the above-described embodiments based on a program for performing the above-described embodiments of the present disclosure stored in the memory (1510).

[0307] 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.

[0308] 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).

[0309] 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.

[0310] 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.

[0311] 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.

[0312] 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.

[0313] 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.

[0314] Meanwhile, although the detailed description of the present disclosure has described specific embodiments, 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 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.

[0315] 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. In a method of a first ProSe enabled UE (user equipment) providing ProSe (Proximity based services) Relay function in a wireless communication system, A step of receiving a request message for relay discovery from a second ProSe enabled UE; a step of adjusting at least one parameter included in the above request message; and comprising a step of transmitting the above request message to a third ProSe enabled UE; A method, characterized in that at least one parameter included in the request message includes at least one multi-hop related parameter.

2. In the first paragraph, at least one multi-hop related parameter is, A method characterized by including a value for the maximum number of hops for the above relay discovery.

3. In the first paragraph, at least one multi-hop related parameter is, A method characterized in that it includes a value for the number of hops and at least one user info identifier of at least one relay.

4. In paragraph 3, A step of receiving a response message to the request message from the third ProSe enabled UE; A method characterized in that the response message is received through a path determined based on at least one of a value for the number of hops, wireless channel state information of a relay to which the request message was transmitted, and delay information.

5. In paragraph 2, A step of adjusting at least one parameter; A method characterized by comprising the step of adjusting the value of the maximum number of hops for the above relay discovery to a value lower by 1.

6. In paragraph 2, Further comprising a step of receiving a second request message for relay discovery from the second ProSe enabled UE; The second request message is transmitted if the response message is not received within a predetermined time, and A method characterized in that the second request message includes a value for the maximum number of adjusted hops.

7. In paragraph 2, A method characterized by comprising a step of discarding the request message if the value for the maximum number of hops for the relay discovery is less than or equal to a predetermined value.

8. In a method of a second ProSe (Proximity based services) enabled UE (user equipment) in a wireless communication system, A step of transmitting a request message for relay discovery to a first ProSe enabled UE (user equipment) providing ProSe Relay function; At least one parameter included in the above request message is adjusted, The above request message is transmitted to the third ProSe enabled UE, and A method, characterized in that at least one parameter included in the request message includes at least one multi-hop related parameter.

9. In paragraph 8, Further comprising a step of receiving a response message to the request message from the third ProSe enabled UE through the first ProSe enabled UE; A method characterized in that the response message is received through a path determined based on at least one of a value for the number of hops included in the request message, wireless channel state information of a relay to which the request message is transmitted, and delay information.

10. In paragraph 9, further comprising a step of transmitting a second request message for relay discovery to the first ProSe enabled UE if the above response message is not received within a predetermined time; A method characterized in that the second request message includes a value for the maximum number of adjusted hops.

11. In a first ProSe enabled UE (user equipment) providing ProSe (Proximity based services) Relay function in a wireless communication system, Transmitter and receiver; and comprising at least one processor; wherein the at least one processor comprises: Receive a request message for relay discovery from a second ProSe enabled UE, Adjusting at least one parameter included in the above request message, and configured to transmit the above request message to a third ProSe enabled UE, 1 ProSe enabled UE, characterized in that at least one parameter included in the request message includes at least one multi-hop related parameter.

12. In the 11th paragraph, at least one multi-hop related parameter is, A first ProSe enabled UE characterized by including a value for the maximum number of hops for the above relay discovery.

13. In the 11th paragraph, at least one multi-hop related parameter is, A first ProSe enabled UE characterized by comprising a value for the number of hops, at least one user info identifier of at least one relay.

14. In a wireless communication system, in a second ProSe (Proximity based services) enabled UE (user equipment), Transmitter and receiver; and comprising at least one processor; wherein the at least one processor comprises: It is configured to transmit a request message for relay discovery to a first ProSe enabled UE (user equipment) that provides the ProSe Relay function, At least one parameter included in the above request message is adjusted, The above request message is transmitted to the third ProSe enabled UE, and A second ProSe enabled UE, characterized in that at least one parameter included in the request message includes at least one multi-hop related parameter.

15. In paragraph 14, at least one processor, configured to receive a response message to the request message from the third ProSe enabled UE through the first ProSe enabled UE, A second ProSe enabled UE, characterized in that the response message is received through a path determined based on at least one of a value for the number of hops included in the request message, wireless channel state information of a relay to which the request message is transmitted, and delay information.

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