WO2025018837A1 - Communication method using network relay in multi-hop environment and apparatus therefor - Google Patents

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

The present disclosure relates to a communication system, and more specifically, to a method for searching for a 5G ( ^5th generation) ProSe (Proximity based Services) UE-to-Network relay in an environment supporting multiple hop relays.

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 (㎜Wave) such as 28GHz and 39GHz ('Above 6GHz'). In addition, in the case of 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 delay time that is reduced to one-tenth.

In the early stages of 5G mobile communication technology, the goal was to support services and satisfy performance requirements for enhanced Mobile Broadband (eMBB), Ultra-Reliable Low-Latency Communications (URLLC), and massive Machine-Type Communications (mMTC). The technologies included 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.

Currently, discussions are underway on improving and enhancing the initial 5G mobile communication technology in consideration of the services that the 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.

In addition, standardization of wireless interface architecture/protocols for technologies such as the Industrial Internet of Things (IIoT) to support new services through linkage and convergence with other industries, Integrated Access and Backhaul (IAB) to provide nodes for expanding network service areas by integrating wireless backhaul links and access links, Mobility Enhancement including Conditional Handover and Dual Active Protocol Stack (DAPS) handover, and 2-step RACH for NR to simplify random access procedures is also in progress, and standardization of system architecture/services for 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 is also in progress.

When such 5G mobile communication systems are commercialized, an explosive increase in connected devices will be connected to the communication network, which will require enhanced functions and performance of 5G mobile communication systems and integrated operation of connected devices. To this end, new research will be conducted on improving 5G performance and reducing complexity, AI service support, metaverse service support, drone communications, etc. using extended reality (XR), artificial intelligence (AI), and machine learning (ML) to efficiently support augmented reality (AR), virtual reality (VR), and mixed reality (MR).

In addition, the development of these 5G mobile communication systems will require 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), and Reconfigurable Intelligent Surface (RIS) technology, as well as full duplex technology to improve the frequency efficiency and system network of 6G mobile communication technology, satellite, and AI (Artificial Intelligence) from the design stage and AI-based communication technology that implements end-to-end AI support functions to realize system optimization, and ultra-high-performance communication and computing resources to provide services with a level of complexity that goes beyond the limits of terminal computing capabilities. It could serve as a basis for the development of next-generation distributed computing technologies that utilize this.

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

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

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 belongs from the description below.

In accordance with an 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: 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 a 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.

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 a 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 capable UE.

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, wherein the control unit is configured to receive, from a second UE supporting connection to a network for a ProSe capable UE, an announcement message for UE-to-Network relay discovery, wherein the announcement message includes hop count information indicating a 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.

In another embodiment of the present disclosure, in a wireless communication system, a second UE for ProSe supporting multi-hop relay 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, wherein the second UE may be a UE that supports connection to a network for a ProSe-enabled UE.

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

In addition, according to one embodiment of the present disclosure, ProSe can be effectively supported in a multi-hop environment. Specifically, a communication process between a UE and a network through at least one relay can be efficiently performed.

The effects obtainable from the present disclosure are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by a person skilled in the art to which the present disclosure belongs from the description below.

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

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

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

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

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

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

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

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.

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

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

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

At this time, it should be noted that in the attached drawings, the same components are indicated by the same symbols as much as possible. In addition, 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 contents that are well known in the technical field to which the present disclosure belongs 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.

For the same reason, some components in the attached drawings are exaggerated, omitted, or schematically illustrated. In addition, the size of each component does not entirely reflect the actual size. The same or corresponding components in each drawing are given the same reference numbers.

The advantages and features of the present disclosure, and the methods for achieving them, will become apparent by referring to the embodiments described in detail below together with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below and may be implemented in various different forms, and the embodiments are provided only to make the disclosure of the present disclosure complete and to fully inform a person having ordinary skill in the art to which the present disclosure belongs 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.

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 loaded onto 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 be directed to a computer or other programmable data processing equipment to implement the function in a specific manner, so that the instructions stored in the computer-available or computer-readable memory can also produce a manufactured article including 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 apparatus, a series of operational steps may be performed on the computer or other programmable data processing apparatus to produce a computer-executable process, so that the instructions executing the computer or other programmable data processing apparatus may also provide steps for executing the functions described in the flowchart block(s).

Additionally, each block may represent a module, segment, or portion of code that contains one or more executable instructions for performing a particular logical function(s). It should also be noted that in some alternative implementation examples, the functions mentioned in the blocks may occur out of order. For example, two blocks shown in succession may in fact be performed substantially concurrently, or the blocks may sometimes be performed in reverse order, depending on the functionality they perform.

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

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 similar technical backgrounds or channel types 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 as judged by a person having skilled technical knowledge.

In the following description, terms used to identify connection nodes, terms referring to network entities or NFs (network functions), terms referring to messages, terms referring to interfaces between network objects, terms referring to various identification information, etc. are 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.

For convenience of explanation below, some terms and names defined in the 3GPP (3rd generation partnership project long term evolution) standard may be used. However, the present disclosure is not limited to the above terms and names, and may be equally applied to systems conforming to other standards.

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

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

(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.

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

In addition, although the embodiments of the present disclosure are described below using a 5G system as an example, the embodiments of the present disclosure may be applied to other communication systems having similar technical backgrounds. 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 as judged by a person having skilled technical knowledge.

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. The 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 mean a network entity, a network component, and/or a network resource.

According to one embodiment of the present disclosure, 5GC may include NFs as illustrated in FIG. 1. Of course, the 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.

AMF (Access and Mobility Management Function) (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 confirmation, authentication, and mobility event generation.

The SMF (Session Management Function) (107) may be a network function that manages a PDN (Packet Data Network) connection provided to a user equipment (UE). The PDN connection may be referred to as a PDU (Packet Data Unit) session. For example, the SMF may perform network functions such as session management functions through the establishment, modification, and release of sessions and the maintenance of tunnels between the UPF and RAN required therefor, IP (Internet protocol) address allocation and management functions of the UE, user plane selection and control, traffic processing control in the UPF, and charging data collection control.

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.

Unified Data Management (UDM) (112) may be a network function that stores information about subscribers. 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 that support UE, and managing subscription information.

NEF (Network Exposure Function) (109) may be a function that provides information about a terminal to a server outside the 5G network. In addition, NEF may provide a function that provides information necessary for service to the 5G network and stores it in the UDR.

The UPF (User Plane Function) (103) may be a function that performs a gateway role for transferring user data (PDU) to the DN (Data Network) (104). More specifically, the UPF may perform a role for processing data 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 performing an anchor role between radio access technologies (RATs), packet routing and forwarding, packet inspection, applying user plane policies, creating traffic usage reports, and buffering.

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

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

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

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.

Additionally, terms used in this disclosure can be defined as follows.

ProSe (ProSe Service or Proximity based Service) (proximity 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 through a direct data path without going through the core network.

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

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 a ProSe-enabled UE and a network.

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.

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).

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.

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

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 so that the 5G ProSe Remote UE (201) can 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.

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

The Model A scheme is a model that uses a single discovery protocol message (Announcement message) (330, 340). In the Model A scheme, a 5G ProSe UE-to-Network Relay (310) can include the relay service that 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).

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

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

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 check the relay service to be used by the RSC based on the message. 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).

In Fig. 4, since multi-hop is supported, not only 5G ProSe Remote UEs located within 1 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 located 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 1 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).

In this disclosure, we propose a method 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.

To support Model A based 5G UE-to-Network Relay discovery scheme 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.

● Authorization Parameters:

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

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

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

● Policy Parameters:

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

- Hop Limits per RSC: determine the value based on service requirement (e.g. service latency).

5G ProSe UE-to-Network Relay requires permission to use Model A scheme based on relayed 5G ProSe UE-to-Network Relay discovery announcement. In 1-hop environment, 5G ProSe UE-to-Network Relay discovery announcement does 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 announcement. 5G ProSe UE-to-UE Relay requires permission to relay 5G ProSe UE-to-Network Relay discovery announcement broadcasted by 5G ProSe UE-to-Network Relay. Therefore, permission can be set for 5G ProSe UE-to-Network Relay, 5G ProSe Remote UE, and 5G ProSe UE-to-Network Relay respectively with authorization parameters. In addition to the authorization parameters listed above, other parameters can be added.

Policy parameters may include RSC and/or hop restrictions per RSC. The 5G ProSe UE-to-UE Relay may also receive the RSC(N) value representing the 5G ProSe UE-to-Network Relay service. That is, when the 5G ProSe UE-to-Network Relay broadcasts a 5G ProSe UE-to-Network Relay Discovery Announcement, the 5G ProSe UE-to-UE Relay may relay this message so that 5G ProSe Remote UEs located more than 1 hop away can receive this message. At this time, the 5G ProSe UE-to-UE Relay may receive the RSC(N) value for the UE-to-Network Relay service for which it should provide the relay service.

The hop limit value limits the number of hops a relayed message can travel. This is to prevent messages from being relayed throughout the network and causing network congestion, and can also be used to adjust the hop limit value to search for a suitable 5G ProSe Remote UE since the distance to each RSC (service) may be different. For example, the hop limit value may be determined based on the ProSe application server and network policy. Or, it may be determined manually by an authorized person depending on the field situation (disaster situation), and this value may precede the value determined by the ProSe application server and network policy.

The hop limit value may be assigned different values depending on the RSC and field situation. For example, in the case of a service used in a small disaster situation such as a traffic accident, the hop limit value may be small, and in the case of a disaster situation that occurs over a wide area such as an earthquake, a large value may be assigned. In addition, if the disaster area is a narrow area such as an island with a low terminal density, the hop limit value may be small, and if it is a wide area such as a large city with a high terminal density, the hop limit value may be assigned a larger value. In addition, in order to avoid network congestion, the 5G ProSe UE-to-Network Relay transmits the first 5G ProSe UE-to-Network Relay Discovery Announcement message using a value higher than the Min. value (minimum value) of the hop limit, but if it does not receive a Relay Service Request message from the 5G ProSe Remote UE for a specified time (Timer), depending on the RSC and the disaster field situation, the value may be set to between the Min. value and the Max. value (maximum value) or the Max. The 5G ProSe UE-to-Network Relay Discovery Announcement can be transmitted by resetting the value to a value greater than the Max. value. Additionally, it can be manually retransmitted by an authorized person depending on the on-site situation (type of disaster, size of area, urgency, etc.).

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

● Parameters for one hop relay:

- Type of Discovery Message,

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

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

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

- Destination Layer-2 ID: Default Destination Layer-2 ID.

● Parameters for multiple hops relay:

- Hop limit: limitation of the number of relays,

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

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

- Parameters for determining path,

- Degree of mobility,

- Status of battery, and/or

- Status of load.

The existing parameters can be named as Parameters for one hop relay. The newly added parameters for multi-hops can be named as Parameters for multiple hops relay. The names suggested here are just examples, and other names may be used, and the existing parameters and the additional parameters may not be distinguished separately.

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.

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.

The type of discovery message indicates the type of message to be 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 a 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 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 that receive 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.

The following describes the values of parameters added in this disclosure.

The hop limit value can represent a value received from the PCF or ProSe application server described above. The hop count is a value that increases for each hop and can represent how many hops the announcement message has 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 path-on message to select when the 5G ProSe Remote UE receives the announcement message delivered through multiple paths 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 have 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 it by adding their own source Layer-2 ID when relaying the message.

The values of mobility degree, battery status, and load status are values that only 5G ProSe UE-to-UE Relay inputs, and can be used as information to select a more stable path when 5G ProSe Remote UE receives an announcement message on multiple paths. The mobility degree can indicate the mobility degree of the relay, that is, 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 that the relay is processing. Since each relay has a different location and the type and number of connection services that it can support, the load processed by each relay can be different. For example, in the case of a path composed of relays with high mobility, frequent relay reselection may occur due to the movement of the relay, and in the case of a path composed of relays with low battery capacity, the power of the relay may be turned off, which may also require relay reselection.

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.

FIG. 5 illustrates relay of a 5G ProSe UE-to-Network Relay discovery Announcement message according to an embodiment of the present disclosure.

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 in the surroundings 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.

The 5G ProSe UE-to-UE Relay (502, 503) can check the RSC(N) value in the message after receiving the message. If the relay is an RSC(N) providing a 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 additionally. For example, the relay can immediately retransmit the message it received first and discard all duplicated messages thereafter, or select a message to retransmit by considering the hop count, the mobility of the relay, the battery, and/or the load status among the duplicated messages received for a certain period of time, or select a message to retransmit by considering the received signal strength.

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.

● Parameters for one hop relay group:

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

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

- RSC(N),

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

- Destination Layer-2 ID: Default destination Layer-2 ID.

● Parameters for multiple hops relay group:

- Hop Limit: Received hop limit - 1,

- Hop count: Received hop count + 1,

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

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

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

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

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.

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

Referring to FIG. 6, the announcement message can be transmitted on two paths. Among the two paths, the message on the upper path (601) is no longer retransmitted because the hop limit value becomes 0, and among the two paths, the message on 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.

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

The 5G ProSe UE-to-Network Relay discovery announcement transmission procedure of Fig. 7 may refer to the description of Figs. 5 and 6.

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.

At step 702, 5G ProSe UE-to-UE Relay-1 and 5G ProSe UE-to-UE Relay-2 can check the RSC(N) value and modify and retransmit the announcement message. 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, check that these two messages are duplicated, and discard one of the messages.

At step 703, 5G ProSe UE-to-UE Relay-3 can check the RSC(N) value and modify and retransmit the announcement message. 5G ProSe Remote UE-1 and 5G ProSe Remote UE-2 can receive the message transmitted by 5G ProSe UE-to-UE Relay-3.

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.

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.

The procedure of Fig. 8 may also be performed in combination with the procedures of Fig. 7 described above.

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 through 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 wireless 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 address value of 5G ProSe UE-to-UE Relay-3, i.e., the source layer-2 ID at the end of the List of Source Layer-2 ID(s) of the announcement message. The List of Source Layer-2 ID(s) value can also be added within the 5G ProSe Direct Communication Request message.

The 5G ProSe UE-to-UE Relay-3, which receives this in step 802, can forward the message to the 5G ProSe UE-to-UE Relay-1 by setting the address of the 5G ProSe UE-to-UE Relay-1, which is its previous 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.

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.

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.

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

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 the configuration illustrated in FIG. 9.

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 can include control information and data. In addition, the transceiver (900) can receive signals through a wireless channel and output them to the processor (920), and transmit the signals output from the processor (920) through the wireless channel.

According to one embodiment of the present disclosure, the processor (920) can control the terminal to perform any one of the operations of the embodiments described above. 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 AP (Application Processor), a CP (Communication Processor), a circuit, an application-specific circuit, or at least one processor.

According to one embodiment of the present disclosure, the memory (910) can store data such as a basic program for the operation of the terminal, an application program, and setting information. 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, the memory (910) can be plural. 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).

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

A network entity according to one embodiment of the present disclosure may include a processor (1020) for controlling 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 the configuration illustrated in FIG. 10.

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 other network entities or terminals can include control information and data.

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

According to one embodiment of the present disclosure, the memory (1010) can store data such as a basic program, an application program, and setting information for the operation of a network entity. In particular, the memory (1010) provides the stored data upon a request of the processor (1020). The memory (1010) 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, the memory (1010) can be plural. In addition, the processor (1020) can perform the above-described embodiments based on a program for performing the above-described embodiments of the present disclosure stored in the memory (1010).

It should be noted that the above-described configuration diagram, example diagram of control/data signal transmission method, example diagram of operation procedure, and configuration diagram are not intended to limit the scope of the present disclosure. That is, not all components, entities, or steps of operations described in the embodiments of the present disclosure should be construed as essential components for implementing the disclosure, and the disclosure may be implemented within a scope that does not harm the essence of the disclosure even if only some components are included. In addition, each embodiment may be combined and operated with each other as needed. For example, some of the methods proposed in the present disclosure may be combined with each other to operate a network entity and a terminal.

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 by a processor or CPU (Central Processing Unit).

The various components, modules, etc. of the entity, base station or terminal device described in this specification may be operated using hardware circuits, for example, logic circuits based on complementary metal oxide semiconductors, firmware, software and/or a combination of 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.

In the case of software implementation, 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 in 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.

These programs (software modules, software) may be stored in a random access memory, a non-volatile memory including a flash memory, a ROM (Read Only Memory), an Electrically Erasable Programmable Read Only Memory (EEPROM), a magnetic disc storage device, a Compact Disc-ROM (CD-ROM), a Digital Versatile Discs (DVDs) or other forms of optical storage devices, a magnetic cassette. Or, they may be stored in a memory composed of a combination of some or all of these. In addition, each configuration memory may be included in multiple numbers.

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 LAN (WLAN), or a Storage Area Network (SAN), or a combination thereof. The 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.

In the specific embodiments of the present disclosure described above, the 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 the convenience of explanation, and the present disclosure is not limited to the singular or plural components, and even if a component is expressed in the plural form, it may be composed of the singular form, or even if a component is expressed in the singular form, it may be composed of the plural form.

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 claims described below but also by the equivalents of the scope of the claims. In other words, it will be obvious to a person having ordinary skill in the art to which the present disclosure pertains that other modifications based on the technical idea of the present disclosure are possible. In addition, each of the above embodiments can be combined and operated with each other as needed. For example, some of the methods proposed in the present disclosure can be combined with each other to operate the base station and the terminal. In addition, although the above embodiments have been presented based on the 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.

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 claims described below, but also by equivalents of the scope of the claims.

Claims (15)

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. 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. In the second paragraph, 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. In the first paragraph, the step of updating the received announcement message comprises: 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. 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). 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. 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. In Article 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. In Article 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). 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. In Article 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. In the 10th paragraph, 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. In Article 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. 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. In Article 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 restriction 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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