Communication method using network relay in multi-hop environment and apparatus therefor

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. A method performed by a first user equipment (UE) for proximity based services (ProSe) supporting multi-hop relay in a wireless communication system according to one embodiment of the present disclosure may comprise the steps of: receiving, from a second UE supporting a connection to a network for a ProSe-enabled UE, an announcement message for UE-to-network relay discovery, wherein the announcement message includes hop count information indicating the number of hops through which the announcement message is relayed; updating the received announcement message; and transmitting the updated announcement message to a third UE.

Description

Communication method using network relay in a multi-hop environment and device therefor

[0001] The present disclosure relates to a communication system, and more specifically, to a 5G (5G) system in an environment supporting multiple hop relays. th We propose a method to search for ProSe (Proximity based Services) UE-to-Network relay.

[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 present disclosure seeks to provide a method and device capable of effectively providing a service in a wireless communication system.

[0009] The present disclosure aims to provide a method and device for effectively supporting ProSe (Proximity based Services) in a multi-hop environment.

[0010] The technical problems to be achieved in the present disclosure are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by a person having ordinary skill in the technical field to which the present invention pertains from the description below.

[0011] In accordance with one embodiment of the present disclosure, a method performed by a first user equipment (UE) for Proximity based Services (ProSe) supporting multi-hop relay in a wireless communication system may include the steps of: receiving an announcement message for UE-to-Network relay discovery from a second UE supporting connection to a network for a ProSe capable UE; the announcement message including hop count information indicating the number of hops through which the announcement message is relayed; updating the received announcement message; and transmitting the updated announcement message to a third UE.

[0012] In another embodiment of the present disclosure, a method performed by a second UE for ProSe supporting multi-hop relay in a wireless communication system includes the steps of generating an announcement message for UE-to-Network relay discovery, the announcement message including hop count information indicating the number of hops through which the announcement message is relayed, and transmitting the announcement message to a first UE, wherein the first UE may be a UE that updates the announcement message and relays it to a third UE, and the second UE may be a UE that supports connection to a network for a ProSe-enabled UE.

[0013] In another embodiment of the present disclosure, a first UE for ProSe supporting multi-hop relay in a wireless communication system includes a transceiver and a control unit, and the control unit is configured to receive an announcement message for UE-to-Network relay discovery from a second UE supporting connection to a network for a ProSe-enabled UE, wherein the announcement message includes hop count information indicating the number of hops through which the announcement message is relayed, update the received announcement message, and transmit the updated announcement message to a third UE.

[0014] In another embodiment of the present disclosure, a second UE for ProSe supporting multi-hop relay in a wireless communication system includes a transceiver and a control unit, wherein the control unit generates an announcement message for UE-to-Network relay discovery, the announcement message including hop count information indicating the number of hops through which the announcement message is relayed, and is configured to transmit the announcement message to a first UE that updates the announcement message and relays it to a third UE, and the second UE may be a UE that supports connection to a network for a ProSe-enabled UE.

[0015] According to one embodiment of the present disclosure, a service can be effectively provided in a wireless communication system.

[0016] Additionally, according to one embodiment of the present disclosure, ProSe can be effectively supported in a multi-hop environment. Specifically, communication between a UE and a network via at least one relay can be efficiently performed.

[0017] The effects that can be obtained from the present disclosure are not limited to the effects mentioned above, and other effects that are not mentioned can be clearly understood by a person having ordinary skill in the art to which the present disclosure belongs from the description below.

[0018] FIG. 1 illustrates the structure of a 5G network according to one embodiment of the present disclosure.

[0019] FIG. 2 illustrates a 5G ProSe UE-to-Network relay structure supporting multiple hops according to an embodiment of the present disclosure.

[0020] FIG. 3 illustrates a model A scheme for 5G ProSe UE-to-Network relay discovery according to one embodiment of the present disclosure.

[0021] FIG. 4 illustrates a Model A scheme for 5G ProSe UE-to-Network relay discovery in an environment supporting multiple hops according to an embodiment of the present disclosure.

[0022] FIG. 5 illustrates relay of a 5G ProSe UE-to-Network Relay Discovery Announcement message according to one embodiment of the present disclosure.

[0023] FIG. 6 illustrates a point in time when relaying of a 5G ProSe UE-to-Network relay discovery announcement message is terminated according to an embodiment of the present disclosure.

[0024] FIG. 7 illustrates a 5G ProSe UE-to-Network relay discovery announcement transmission procedure according to one embodiment of the present disclosure.

[0025] FIG. 8 illustrates a procedure for a ProSe Remote UE to transmit user data using a 5G ProSe UE-to-Network relay service according to an embodiment of the 5G present disclosure.

[0026] FIG. 9 is a diagram showing the configuration of a terminal according to an embodiment of the present disclosure.

[0027] FIG. 10 is a diagram illustrating a configuration of a base station or network entity according to one embodiment of the present disclosure.

[0028] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the attached drawings.

[0029] At this time, it should be noted that identical components in the attached drawings are indicated by identical symbols, where possible. Furthermore, detailed descriptions of known functions and configurations that may obscure the gist of the present disclosure will be omitted. In describing the embodiments of the present disclosure, 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 disclosure will be omitted. This is to convey the gist of the present disclosure more clearly without obscuring it by omitting unnecessary explanations.

[0030] 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.

[0031] 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.

[0032] 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).

[0033] 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.

[0034] 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.

[0035] Hereinafter, a 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.

[0036] Furthermore, the embodiments of the present disclosure may be applied to other communication systems having similar technical backgrounds or channel types to the embodiments of the present disclosure described below. 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.

[0037] 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.

[0038] 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.

[0039] FIG. 1 illustrates the structure of a 5G network according to one embodiment of the present disclosure.

[0040] Referring to FIG. 1, a 5G network may include network entities or network nodes described below.

[0041] (R)AN ((Radio) Access Network) (102) 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 (Next Generation Radio Access Network), a 5G-AN, a wireless access unit, a base station controller, or a node on a network.

[0042] The terminal (101) may include a UE (User Equipment), NG UE (Next Generation UE), MS (Mobile Station), cellular phone, smartphone, computer, or multimedia system capable of performing a communication function.

[0043] Furthermore, while the embodiments of the present disclosure are described below using a 5G system as an example, the embodiments of the present disclosure can also be applied to other communication systems with similar technical backgrounds. Furthermore, the embodiments of the present disclosure can be applied to other communication systems with some modifications, as determined by a person skilled in the art, without significantly departing from the scope of the present disclosure.

[0044] As wireless communication systems evolve from 4G systems to 5G systems, a new core network, the 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, and / or a network resource.

[0045] According to one embodiment of the present disclosure, 5GC may include NFs illustrated in FIG. 1. Of course, the present invention is not limited to the example illustrated in FIG. 1, and 5GC may include more or fewer NFs than the NFs illustrated in FIG. 1.

[0046] An Access and Mobility Management Function (AMF) (106) 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.

[0047] The SMF (Session Management Function) (107) 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 tunnels between the UPF and the RAN required for this, assigning and managing the IP (Internet protocol) address of the UE, selecting and controlling the user plane, controlling traffic processing in the UPF, and controlling the collection of charging data.

[0048] PCF (Policy Control Function) (111) may be a network function that applies a mobile communication service provider's service policy, charging policy, and policy for PDU sessions to a terminal.

[0049] Unified Data Management (UDM) (112) may be a network function that stores subscriber information. For example, UDM may perform functions such as generating authentication information for 3GPP security, processing user identifiers (user IDs), managing a list of network functions supporting UEs, and managing subscription information.

[0050] The Network Exposure Function (NEF) (109) may be a function that provides information about a terminal to a server outside the 5G network. Furthermore, NEF may provide the function of storing information necessary for 5G network services in the UDR.

[0051] The User Plane Function (UPF) (103) may be a function that acts as a gateway to transfer user data (PDU) to the Data Network (DN) (104). More specifically, the UPF may perform a data processing function so that data transmitted by a terminal can be transferred to an external network or data received from an external network can be transferred to the terminal. For example, the UPF may perform network functions such as serving as an anchor between radio access technologies (RATs), packet routing and forwarding, packet inspection, user plane policy application, traffic usage report creation, and buffering.

[0052] NRF (Network Repository Function) (110) can perform the function of discovering NF.

[0053] AUSF (Authentication Server Function) (105) can perform terminal authentication in 3GPP access networks and non-3GPP access networks.

[0054] NSSF (Network Slice Selection Function) (108) can perform the function of selecting a network slice instance provided to a terminal.

[0055] DN (Data Network) (104) 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.

[0056] Additionally, terms used in this disclosure may be defined as follows.

[0057] 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 can be exchanged directly through a data path without going through the core network.

[0058] A ProSe-enabled UE (proximity service-enabled terminal) refers to a UE that supports ProSe discovery and / or ProSe communication.

[0059] 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.

[0060] 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.

[0061] ProSe remote UE refers to a ProSe-enabled UE that communicates with a data network via a relay (e.g., ProSe UE-to-Network Relay, ProSe UE-to-UE Relay).

[0062] 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.

[0063] FIG. 2 illustrates a 5G ProSe UE-to-Network relay structure supporting multiple hops according to an embodiment of the present disclosure.

[0064] Referring to FIG. 2, a 5G ProSe Remote UE (201), a 5G ProSe UE-to-UE Relay (202), and a 5G ProSe UE-to-Network Relay (203) are all 5G ProSe enabled UEs, and the 5G ProSe Remote UE can communicate with the NG-RAN (network) (204) in a multi-hop environment using the 5G ProSe UE-to-UE Relay and the 5G ProSe UE-to-Network Relay. The 5G ProSe UE-to-UE Relay (202) and the 5G ProSe UE-to-Network Relay (203) can provide a data relay service to enable the 5G ProSe Remote UE (201) to communicate with the network in a multi-hop environment. In addition, the 5G ProSe enabled UEs can use the PC5 interface to transmit data and signaling. 5G ProSe enabled UE and NG-RAN (network) (204) can use the Uu interface for user data transmission.

[0065] FIG. 3 illustrates a model A scheme for 5G ProSe UE-to-Network Relay discovery according to one embodiment of the present disclosure.

[0066] Model A is a model that uses a single discovery protocol message (Announcement message) (330, 340). In Model A, a 5G ProSe UE-to-Network Relay (310) can include the relay service it can provide in the form of a Relay Service Code (RSC) in a 5G ProSe UE-to-Network Relay Discovery Announcement message (330, 340) and transmit it to surrounding 5G ProSe Remote UEs (300, 320).

[0067] The 5G ProSe Remote UE (300, 320) that receives the above 5G ProSe UE-to-Network Relay Discovery Announcement message (330, 340) can determine the 5G ProSe UE-to-Network Relay that provides the relay service to be used based on the RSC and initiate relay communication using the 5G ProSe UE-to-Network Relay.

[0068] FIG. 4 illustrates a Model A scheme for 5G ProSe UE-to-Network Relay discovery in an environment supporting multiple hops according to an embodiment of the present disclosure.

[0069] Referring to FIG. 4, a 5G ProSe UE-to-Network Relay (401) can broadcast the relay service it provides to the surroundings by including it in a 5G ProSe UE-to-Network Relay Discovery Announcement message in the RSC format. 5G ProSe Remote UEs located within the transmission radius (402) of the 5G ProSe UE-to-Network Relay (401) can receive this message and, based on the message, determine the relay service to be used by the RSC. When the relay service is provided, the 5G ProSe Remote UEs can transmit data to the NG-RAN (403) using the 5G ProSe UE-to-Network Relay (401).

[0070] In FIG. 4, since multiple hops are supported, not only 5G ProSe Remote UEs within one hop of the 5G ProSe UE-to-Network Relay, i.e., within the transmission radius of the 5G ProSe UE-to-Network Relay, but also 5G ProSe Remote UEs outside the transmission radius should be able to utilize the 5G ProSe UE-to-Network Relay (401). In other words, 5G ProSe Remote UEs located more than one hop away from the 5G ProSe UE-to-Network Relay should also be able to receive the 5G ProSe UE-to-Network Relay Discovery Announcement message broadcast by the 5G ProSe UE-to-Network Relay (401).

[0071] In this disclosure, a method is proposed in which a 5G ProSe Remote UE located several hops away from a 5G ProSe UE-to-Network Relay can also utilize the 5G ProSe UE-to-Network Relay in an environment supporting multiple hops as illustrated in FIG. 4.

[0072] To support Model A-based 5G UE-to-Network Relay discovery in an environment supporting multiple hops, 5G ProSe UE-to-Network Relay, 5G ProSe UE-to-UE Relay, or 5G ProSe Remote UE may additionally receive the following authorization parameters / policy parameters from PCF or ProSe Application Server via PCF.

[0073] ● Authorization Parameters:

[0074] - Authorization on using Model A based on relayed 5G ProSe UE-to-Network Relay Discovery Announcement to 5G ProSe UE-to-Network Relay

[0075] - Authorization on using Model A based on relayed 5G ProSe UE-to-Network Relay Discovery Announcement to 5G ProSe Remote UE, and / or

[0076] - Authorization on relaying announcement message to 5G ProSe UE-to-UE Relay.

[0077] ● Policy Parameters:

[0078] - RSC(N): 5G ProSe UE-to-UE Relays provide RSC regarding relay to network service, and / or

[0079] - Hop Limits per RSC: Determine the value based on service requirement (e.g. service latency).

[0080] 5G ProSe UE-to-Network Relay requires permission to use Model A scheme based on relayed 5G ProSe UE-to-Network Relay discovery announcements. In a 1-hop environment, 5G ProSe UE-to-Network Relay discovery announcements did not need to be relayed. In addition, 5G ProSe Remote UE also requires permission to use Model A scheme based on relayed 5G ProSe UE-to-Network Relay discovery announcements. 5G ProSe UE-to-UE Relay requires permission to relay 5G ProSe UE-to-Network Relay discovery announcements broadcast by 5G ProSe UE-to-Network Relay. Therefore, permissions can be set for 5G ProSe UE-to-Network Relay, 5G ProSe Remote UE, and 5G ProSe UE-to-Network Relay respectively using authorization parameters. In addition to the authorization parameters listed above, other parameters can also be added.

[0081] Policy parameters may include RSC and / or hop restrictions per RSC. The 5G ProSe UE-to-UE Relay can also receive the RSC(N) value indicating the 5G ProSe UE-to-Network Relay service. That is, when the 5G ProSe UE-to-Network Relay broadcasts the 5G ProSe UE-to-Network Relay Discovery Announcement, the 5G ProSe UE-to-UE Relay can relay this message so that 5G ProSe Remote UEs located more than one hop away can receive this message. At this time, the 5G ProSe UE-to-UE Relay can receive the RSC(N) value for the UE-to-Network Relay service for which it should provide the relay service.

[0082] The hop limit value limits the number of hops a relayed message can travel. This prevents messages from being relayed across the network, causing network congestion. Furthermore, since the distance to a suitable 5G ProSe Remote UE may vary for each RSC (service), the hop limit value can be adjusted to discover a suitable 5G ProSe Remote UE. For example, the hop limit value may be determined by the ProSe application server and network policies. Alternatively, it may be determined manually by an authorized person depending on the on-site situation (e.g., a disaster situation), and this value may precede the value determined by the ProSe application server and network policies.

[0083] The hop limit value can be assigned different values ​​depending on the RSC and the on-site situation. For example, a service used in a small disaster situation such as a traffic accident may have a small hop limit value, while a large value may be assigned to a disaster situation that occurs over a wide area such as an earthquake. Furthermore, a small hop limit value may be assigned if the disaster area is a narrow, low-density area such as an island, while a large, high-density area such as a large city may have a larger hop limit value. Furthermore, to avoid network congestion, the 5G ProSe UE-to-Network Relay initially transmits the 5G ProSe UE-to-Network Relay Discovery Announcement message using a hop limit value greater than the Min. value (minimum value). However, if a Relay Service Request message is not received from the 5G ProSe Remote UE within a specified time (Timer), the value may be set to between the Min. value and the Max. value, or to the Max. value, depending on the RSC and the on-site situation. The 5G ProSe UE-to-Network Relay Discovery Announcement can be sent by resetting the value. Additionally, depending on the on-site situation (disaster type, area size, urgency, etc.), the value can be manually set to a value greater than the Max. value and retransmitted by an authorized person.

[0084] The 5G ProSe UE-to-Network Relay discovery announcement message in a multi-hop environment may include additional parameters in addition to the existing parameters.

[0085] ● Parameters for one hop relay:

[0086] - Type of Discovery Message,

[0087] - User Info ID: 5G ProSe UE-to-Network Relay,

[0088] - RSC(N) (Relay Service Code for UE-to-Network Relay),

[0089] - Source Layer-2 ID: self-assign per RSC (Once allocate it, it will use this ID)

[0090] - Destination Layer-2 ID: Default Destination Layer-2 ID.

[0091] ● Parameters for multiple hops relay:

[0092] - Hop limit: limitation of the number of relays,

[0093] - Hop Counts: the number of hops it is relayed,

[0094] - List of Source Layer-2 ID(s): List of source layer-2 ID(s) of Relays,

[0095] - Parameters for determining path,

[0096] - Degree of mobility,

[0097] - Status of battery, and / or

[0098] - Status of load.

[0099] The existing parameters can be named "Parameters for one-hop relay". The newly added parameters for multi-hop relay can be named "Parameters for multiple-hop relay". The names suggested here are only examples; other names may be used, and the existing parameters and additional parameters may not be distinguished separately.

[0100] Existing parameters may include the type of discovery message, RSC, User Info ID (5G ProSe UE-to-Network Relay), source Layer-2 ID, and destination Layer-2 ID.

[0101] Additional parameters may include at least one of the following information: hop limit, hop count, list of source Layer-2 ID(s), mobility level, battery status, and load status.

[0102] The discovery message type indicates the type of message being transmitted. The User Info ID is a value set in the 5G ProSe UE-to-Network Relay for 5G ProSe UE-to-Network Relay discovery. RSC(N) indicates the connectivity service provided by the 5G ProSe UE-to-Network Relay. The source Layer-2 ID is an ID for identifying the 5G ProSe UE-to-Network Relay in the Layer 2 layer. In the present disclosure, this ID is self-assigned when the ProSe UE-to-Network Relay first transmits it, and the same ID can be used every time the corresponding RSC is announced. The destination Layer-2 ID indicates the Layer-2 ID values ​​of the 5G ProSe enabled UEs receiving this message. Since the announcement message must be received by all 5G ProSe enabled UEs, a default destination Layer-2 ID value can be assigned. This address means a broadcast message and can be received by all 5G ProSe enabled UEs.

[0103] The following describes the values ​​of parameters added in this disclosure.

[0104] The hop limit value can represent the value received from the PCF or ProSe application server described above. The hop count is a value that increases with each hop and can represent how many hops the announcement message traveled from the 5G ProSe UE-to-Network Relay to arrive at each 5G ProSe UE-to-UE Relay or 5G ProSe Remote UE. This value can be used as a basis for determining which route-on message to select when the 5G ProSe Remote UE receives the announcement message delivered through multiple routes in the future. The value of the list of source Layer-2 ID(s) can include the source Layer-2 IDs of the 5G ProSe UE-to-UE Relays that passed through the ProSe UE-to-Network Relay, i.e., the 5G ProSe UE-to-UE Relays that relayed the announcement message. 5G ProSe UE-to-UE Relays can determine whether to provide relay service based on the RSC(N) value of the received announcement message and relay the message by adding their own source Layer-2 ID.

[0105] The values ​​for mobility level, battery status, and load status are values ​​that are only input by the 5G ProSe UE-to-UE Relay. They can be used as information to select a more stable path when the 5G ProSe Remote UE receives announcement messages through multiple paths. The mobility level can indicate the mobility level of the relay, i.e., the degree of mobility of the relay. The battery status can indicate the available battery capacity of the relay. Since the relay is also a mobile device, it is powered by a battery. The load status can indicate the load of the relay connection service being processed by the relay. Since each relay has a different location and can support different types and numbers of connection services, the load processed by each relay can vary. For example, in a path composed of relays with high mobility, frequent relay reselection may occur due to the movement of the relay. In addition, in a path composed of relays with low battery capacity, the relay may be powered off, which may also require relay reselection.

[0106] In addition to the parameters listed above for determination, other parameters may be added. The scope of the present disclosure is not limited to the parameters listed above.

[0107] FIG. 5 illustrates relay of a 5G ProSe UE-to-Network Relay Discovery Announcement message according to one embodiment of the present disclosure.

[0108] A 5G ProSe UE-to-Network Relay (501) can generate a 5G ProSe UE-to-Network Relay discovery announcement message and broadcast it to the surroundings. One or more 5G ProSe UE-to-UE Relays (502, 503) located nearby can receive the announcement message transmitted by the 5G ProSe UE-to-Network Relay (501). Since the destination Layer-2 ID of the message is set to 'default', all relays can receive this message.

[0109] After receiving the above message, the 5G ProSe UE-to-UE Relay (502, 503) can check the RSC(N) value in the message. If the relay is the RSC(N) providing the connection service, the relay can modify the received 5G ProSe UE-to-Network Relay Discovery Announcement message and retransmit it. The 5G ProSe UE-to-UE Relay can determine that the announcement message it received is duplicated based on the source Layer-2 ID, RSC(N), User Info ID, etc. of the Announcement message and not retransmit the duplicated message. For example, the relay can immediately retransmit the first message received and discard all duplicate messages thereafter, or select a message to retransmit by considering the hop count, mobility of the relay, battery, and / or load conditions among the duplicate messages received over a certain period of time, or select a message to retransmit by considering the received signal strength.

[0110] When relaying an announcement message received by a 5G ProSe UE-to-UE Relay, the message can be retransmitted by modifying at least one of the following parameters.

[0111] ● Parameters for one hop relay group:

[0112] - Type of Discovery Message: 5G ProSe UE-to-Network Relay Discovery Announcement,

[0113] - User Info ID: 5G ProSe UE-to-Network Relay,

[0114] - RSC(N),

[0115] - Source Layer-2 ID: self-assign per RSC, and / or

[0116] - Destination Layer-2 ID: Default destination Layer-2 ID.

[0117] ● Parameters for multiple hops relay group:

[0118] - Hop Limit: Received hop limit - 1,

[0119] - Hop count: Received hop count + 1,

[0120] - List of Source Layer-2 ID(s): Add your Source Layer-2 ID to the list of existing Source Layer-2 ID(s).

[0121] - Degree of Mobility: Add your relay's degree of mobility to the list of existing relays' degrees of mobility.

[0122] - Status of Battery: Add the battery status of your relay to the list of battery statuses of existing relays, and / or

[0123] - Status of Load: Add the load status of your relay to the list of load statuses of existing relays.

[0124] For example, 5G ProSe UE-to-UE Relay can retransmit by changing only the parameter values ​​for the multi-hop relay group and not changing the parameter values ​​for the 1-hop relay group.

[0125] FIG. 6 illustrates a point in time when relaying of a 5G ProSe UE-to-Network relay discovery announcement message is terminated according to an embodiment of the present disclosure.

[0126] Referring to FIG. 6, the announcement message can be transmitted through two paths. Among the two paths, the message of the upper path (601) is no longer retransmitted because the hop limit value becomes 0, and among the two paths, the message of the lower path (602) is no longer retransmitted because there is no 5G ProSe UE-to-UE Relay around it. In this way, the 5G ProSe UE-to-UE Relay that participated in the 5G ProSe UE-to-Network Relay discovery announcement retransmission does not end the 5G ProSe UE-to-Network Relay discovery announcement retransmission service with a single relay, and can also periodically broadcast the 5G ProSe UE-to-Network Relay discovery announcement message that it retransmitted, just as the 5G ProSe UE-to-Network Relay periodically broadcasts it. That is, the 5G ProSe UE-to-UE Relay that participated in the 5G ProSe UE-to-Network Relay Discovery Announcement retransmission will perform the 5G ProSe UE-to-Network Relay Discovery Announcement broadcast task on behalf of the 5G ProSe UE-to-Network Relay. This allows 5G ProSe Remote UEs located several hops away from the 5G ProSe UE-to-Network Relay to receive the 5G ProSe UE-to-Network Relay Discovery Announcement message and use the 5G ProSe UE-to-Network Relay service.

[0127] FIG. 7 illustrates a 5G ProSe UE-to-Network Relay discovery announcement transmission procedure according to one embodiment of the present disclosure.

[0128] The 5G ProSe UE-to-Network Relay discovery announcement transmission procedure of FIG. 7 may refer to the descriptions of FIGS. 5 and 6.

[0129] Referring to FIG. 7, in step 701, a 5G ProSe UE-to-Network Relay may transmit (or broadcast) a 5G ProSe UE-to-Network Relay Discovery Announcement message to the surroundings. 5G ProSe UE-to-UE Relay-1 and 5G ProSe UE-to-UE Relay-2 may receive the 5G ProSe UE-to-Network Relay Discovery Announcement message.

[0130] In step 702, 5G ProSe UE-to-UE Relay-1 and 5G ProSe UE-to-UE Relay-2 can check the RSC(N) value and retransmit the announcement message after modifying it. At this time, 5G ProSe UE-to-UE Relay-3 can simultaneously receive the messages retransmitted by 5G ProSe UE-to-UE Relay-1 and 5G ProSe UE-to-UE Relay-2, determine that these two messages are duplicates, and discard one of the messages.

[0131] In step 703, 5G ProSe UE-to-UE Relay-3 can check the RSC(N) value and retransmit the announcement message after modifying it. 5G ProSe Remote UE-1 and 5G ProSe Remote UE-2 can receive the message transmitted by 5G ProSe UE-to-UE Relay-3.

[0132] 5G ProSe UE-to-UE Relay-1, 5G ProSe UE-to-UE Relay-2, and 5G ProSe UE-to-UE Relay-3, which have completed the above procedure, can periodically broadcast the received 5G ProSe UE-to-Network Relay Discovery Announcement message to the surroundings.

[0133] FIG. 8 illustrates a procedure for a 5G ProSe Remote UE to transmit user data using a 5G ProSe UE-to-Network relay service according to an embodiment of the present disclosure.

[0134] The procedure of FIG. 8 may also be performed in combination with the procedures of FIG. 7 described above.

[0135] In step 801, the 5G ProSe Remote UE-2, which receives the 5G ProSe UE-to-Network Relay Discovery Announcement message, may transmit a 5G ProSe Direct Communication Request message to the 5G ProSe UE-to-UE Relay-3 to use the RSC(N) service. If the 5G ProSe Remote UE-2 receives the 5G ProSe UE-to-Network Relay Discovery Announcement message via multiple paths, the 5G ProSe Remote UE-2 may select a path by considering the Hop Counts, Degree of Mobility, Status of Battery, and / or Status of Load in the Announcement message. In addition, the 5G ProSe Remote UE-2 may additionally select a path by considering the radio status with the relay of the last hop in the order in which the message arrived. The Destination Layer-2 ID of the 5G ProSe Direct Communication Request message can be set to the source layer-2 ID at the end of the List of Source Layer-2 ID(s) of the announcement message, i.e., the address value of 5G ProSe UE-to-UE Relay-3. The List of Source Layer-2 ID(s) value can also be added within the 5G ProSe Direct Communication Request message.

[0136] 5G ProSe UE-to-UE Relay-3, which receives this in step 802, can forward the message to 5G ProSe UE-to-UE Relay-1 by setting the address of 5G ProSe UE-to-UE Relay-1, which is the address before its own address, as the Destination Layer-2 ID based on the List of Source Layer-2 ID(s) value in the 5G ProSe Direct Communication Request message.

[0137] In step 803, the 5G ProSe direct communication request received from the 5G ProSe UE-to-UE Relay-1 is processed by the 5G ProSe UE-to-Network Relay to provide a 5G ProSe UE-to-Network relay service of the 5G ProSe Remote UE-2 located several hops away.

[0138] The method and / or embodiment of the present disclosure described above can be performed by the terminal of FIG. 9 and / or the network entity of FIG. 10.

[0139] FIG. 9 is a diagram showing the configuration of a terminal according to an embodiment of the present disclosure.

[0140] A terminal according to one embodiment of the present disclosure may include a processor (920) that controls the overall operation of the terminal, a transceiver (900) including a transmitter and a receiver, and a memory (910). Of course, the present invention is not limited to the above example, and the terminal may include more or fewer components than those illustrated in FIG. 9.

[0141] According to one embodiment of the present disclosure, the transceiver (900) can transmit and receive signals with network entities or other terminals. The signals transmitted and received with the network entities may include control information and data. In addition, the transceiver (900) can receive signals via a wireless channel, output them to the processor (920), and transmit the signals output from the processor (920) via the wireless channel.

[0142] According to one embodiment of the present disclosure, the processor (920) can control the terminal to perform any one of the operations of the above-described embodiments. Meanwhile, the processor (920), the memory (910), and the transceiver (900) do not necessarily have to be implemented as separate modules, and of course, they can be implemented as a single component in the form of a single chip. In addition, the processor (920) and the transceiver (900) can be electrically connected. In addition, the processor (920) can be an Application Processor (AP), a Communication Processor (CP), a circuit, an application-specific circuit, or at least one processor.

[0143] According to one embodiment of the present disclosure, the memory (910) can store data such as basic programs, application programs, and setting information for the operation of the terminal. In particular, the memory (910) provides the stored data upon request of the processor (920). The memory (910) can be configured as a storage medium or a combination of storage media such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD. In addition, there can be a plurality of memories (910). In addition, the processor (920) can perform the above-described embodiments based on a program for performing the above-described embodiments of the present disclosure stored in the memory (910).

[0144] FIG. 10 is a diagram illustrating a configuration of a base station or network entity according to one embodiment of the present disclosure.

[0145] A network entity according to one embodiment of the present disclosure may include a processor (1020) that controls the overall operation of the network entity, a transceiver (1000) including a transmitter and a receiver, and a memory (1010). 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. 10.

[0146] According to one embodiment of the present disclosure, the transceiver (1000) can transmit and receive signals with at least one of other network entities or terminals. The signals transmitted and received with at least one of the other network entities or terminals may include control information and data.

[0147] According to one embodiment of the present disclosure, the processor (1020) can control a network entity to perform any one of the operations described above. Meanwhile, the processor (1020), the memory (1010), and the transceiver (1000) do not necessarily have to be implemented as separate modules, and can of course be implemented as a single component in the form of a single chip. In addition, the processor (1020) and the transceiver (1000) can be electrically connected. In addition, the processor (1020) can be an Application Processor (AP), a Communication Processor (CP), a circuit, an application-specific circuit, or at least one processor.

[0148] According to one embodiment of the present disclosure, the memory (1010) may store data such as basic programs, application programs, and setting information for the operation of a network entity. In particular, the memory (1010) provides the stored data upon request of the processor (1020). The memory (1010) may be configured as a storage medium or a combination of storage media such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD. In addition, there may be a plurality of memories (1010). In addition, the processor (1020) may perform the above-described embodiments based on a program for performing the above-described embodiments of the present disclosure stored in the memory (1010).

[0149] 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.

[0150] 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).

[0151] 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.

[0152] 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.

[0153] 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.

[0154] 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.

[0155] 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.

[0156] While the detailed description of the present disclosure has described specific embodiments, it should be understood 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 claims described below but also by equivalents thereof. 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, the above-described 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-described embodiments have been presented based on a 5G, NR system, other modifications based on the technical idea of ​​the above-described embodiments can be implemented with other systems such as LTE, LTE-A, and LTE-A-Pro systems.

[0157] While the detailed description of this disclosure has described specific embodiments, it should be understood that various modifications are possible without departing from the scope of this disclosure. Therefore, the scope of this disclosure should not be limited to the described embodiments, but should be defined not only by the scope of the claims described below, but also by equivalents thereof.

Claims

1. A method performed by a first terminal (user equipment, UE) for proximity-based services (ProSe) supporting multi-hop relay in a wireless communication system, A step of receiving an announcement message for UE-to-Network relay discovery from a second UE supporting connection to a network for a ProSe capable UE, the announcement message including hop count information indicating the number of hops through which the announcement message is relayed; Step of updating the received announcement message; and A method comprising the step of transmitting an updated announcement message to a third UE.

2. In paragraph 1, Further comprising a step of checking whether a relay service is provided based on a relay service code (RSC) in the above announcement message; The above announcement message further includes hop limit information indicating the maximum number of hops through which the above announcement message can be relayed, and A method characterized in that when it is confirmed that the above relay service is provided, an updated announcement message is transmitted to the third UE.

3. In paragraph 2, If the value of the above hop count information is less than the value of the above hop limit information, the updated announcement message is transmitted to the third UE, and A method characterized in that the above updated announcement message is broadcast periodically.

4. In paragraph 1, the step of updating the received announcement message is: A step of increasing the value of the above hop count information by 1; and A method characterized by comprising the step of adding a source layer-2 identifier (ID) of the first UE to a list of source layer-2 IDs in the received announcement message.

5. In paragraph 1, Further comprising the step of receiving from a network entity at least one of: authorization information instructing the first UE to perform relay of the announcement message or hop limitation information indicating a maximum number of hops through which the announcement message can be relayed; A method characterized in that the above hop limit information is set for each relay service code (RSC).

6. In paragraph 1, A step of receiving a ProSe direct communication request message from the third UE; and A step of updating a received ProSe direct communication request message by setting a destination layer 2 identifier based on the address of the second UE; and A method further comprising the step of transmitting an updated ProSe Direct Communication Request message to the second UE.

7. A method performed by a second terminal (user equipment, UE) for proximity-based services (ProSe) supporting multi-hop relay in a wireless communication system, A step for generating an announcement message for UE-to-Network relay discovery, the announcement message including hop count information indicating the number of hops through which the announcement message is relayed; and Comprising the step of transmitting the announcement message to the first UE, The above first UE is a UE that updates the announcement message and relays it to the third UE, and A method wherein the second UE is a UE that supports connection to a network for a ProSe-enabled UE.

8. In paragraph 7, A method characterized in that the above announcement message further includes hop limitation information indicating the maximum number of hops through which the above announcement message can be relayed.

9. In paragraph 7, Further comprising the step of receiving from a network entity at least one of: acknowledgement information indicating that relaying of said announcement message through multiple hops is approved; or hop restriction information indicating a maximum number of hops through which said announcement message can be relayed; A method characterized in that the above hop limit information is set for each relay service code (RSC).

10. In a first terminal (user equipment, UE) for proximity-based services (ProSe) supporting multi-hop relay in a wireless communication system, Transmitter and receiver; and A control unit comprising: Receive an announcement message for UE-to-Network relay discovery from a second UE that supports connection to a network for a ProSe-enabled UE, wherein the announcement message includes hop count information indicating the number of hops through which the announcement message is relayed; Updates the received announcement message, and A first UE configured to transmit an updated announcement message to a third UE.

11. In paragraph 10, The above control unit is further configured to check whether a relay service is provided based on a relay service code (RSC) in the above announcement message, The above announcement message further includes hop limit information indicating the maximum number of hops through which the above announcement message can be relayed, and A first UE, characterized in that when it is confirmed that the relay service is provided and the value of the hop count information is less than the value of the hop limit information, the updated announcement message is transmitted to the third UE.

12. In paragraph 10, to update the received announcement message, the control unit: Increase the value of the above hop count information by 1, and A first UE, characterized in that the first UE is configured to add the source layer-2 identifier (ID) of the first UE to the list of source layer-2 IDs in the received announcement message.

13. In paragraph 10, The control unit is further configured to receive from a network entity at least one of authorization information instructing the first UE to perform relay of the announcement message or hop limitation information indicating a maximum number of hops through which the announcement message can be relayed. The above hop limit information is set by relay service code (RSC), and The first UE characterized in that the above updated announcement message is broadcast periodically.

14. In a second terminal (user equipment, UE) for proximity-based services (ProSe) supporting multi-hop relay in a wireless communication system, Transmitter and receiver; and A control unit comprising: Generate an announcement message for UE-to-Network relay discovery, wherein the announcement message includes hop count information indicating the number of hops through which the announcement message is relayed, and The above announcement message is set to be transmitted to the first UE, which relays the above announcement message to the third UE, The second UE is a UE that supports connection to the network for a ProSe-enabled UE.

15. In paragraph 14, The control unit is further configured to receive from the network entity at least one of: approval information indicating that relaying of the announcement message through multiple hops is approved; or hop limitation information indicating the maximum number of hops through which the announcement message can be relayed; The above announcement message further includes hop limit information indicating the maximum number of hops through which the above announcement message can be relayed, and A second UE, characterized in that it further includes steps, and wherein the hop limitation information is set per relay service code (RSC).

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