Method and device for searching for data path in wireless communication system

Abstract

The present disclosure provides a method performed by a first relay terminal in a wireless communication system including a first terminal, a second terminal, the first relay terminal, and a second relay terminal supporting a proximity based service (ProSe). The method comprises the steps of: receiving a first message for discovery for the second terminal from the first terminal; and transmitting a second message to the second relay terminal on the basis of the first message, wherein the first message includes first information for a relay service and second information for a multi-hop relay.

Description

Method and device for exploring a data path in a wireless communication system

[0001] The present disclosure relates to a wireless communication system. More particularly, it relates to a method and device for discovering a reliable data path in an environment supporting multi-hop relays in a wireless communication system.

[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 multiple hops 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 disclosure belongs from the description below.

[0011] According to one embodiment of the present disclosure, a method for processing a control signal in a wireless communication system may include: receiving a first control signal transmitted from a base station; processing the received first control signal; and transmitting a second control signal generated based on the processing to the base station.

[0012] According to the embodiments proposed in the present disclosure, a device and method capable of effectively providing a service in a wireless communication system are provided.

[0013] 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.

[0014] FIG. 1 is a diagram illustrating the structure of a 5G network according to one embodiment of the present disclosure.

[0015] FIG. 2 illustrates a 5G ProSe (Proximity based Services) UE-to-Network Relay structure supporting multiple hops according to one embodiment of the present disclosure.

[0016] FIG. 3 illustrates a 5G ProSe (Proximity based Services) UE-to-UE Relay structure supporting multiple hops according to one embodiment of the present disclosure.

[0017] FIG. 4 illustrates an example of a communication interruption situation that may occur in ProSe communication supporting Multiple Hops according to one embodiment of the present disclosure.

[0018] FIG. 5 illustrates a procedure for a 5G ProSe enabled UE to search for a data path to transmit data according to an embodiment of the present disclosure.

[0019] FIG. 6 illustrates a scenario of redundantly transmitting the same data through multiple data transmission paths according to one embodiment of the present disclosure.

[0020] FIG. 7 illustrates data transmission in a flooding manner that transmits data directly without searching for a data path according to one embodiment of the present disclosure.

[0021] Figure 8 illustrates the structure of a terminal according to one embodiment of the present disclosure.

[0022] FIG. 9 illustrates a base station or network entity structure according to one embodiment of the present disclosure.

[0023] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. It should be noted that, where possible, identical components are represented by identical reference numerals throughout the attached drawings. Furthermore, detailed descriptions of well-known functions and configurations that may obscure the gist of the present invention will be omitted.

[0024] In describing the embodiments herein, descriptions of technical details that are well known in the technical field to which the present disclosure pertains and are not directly related to the present invention will be omitted. This is to avoid obscuring the gist of the present disclosure by omitting unnecessary explanations and to convey the gist more clearly.

[0025] 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.

[0026] 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.

[0027] At this time, it will be understood that each block of the processing flowchart drawings and combinations of the flowchart drawings 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 flowchart 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 flowchart 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).

[0028] 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.

[0029] 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.

[0030] Hereinafter, the base station is an entity that performs resource allocation of a terminal, and may be at least one of a Node B, a BS (Base Station), an eNB (eNode B), a gNB (gNode B), a wireless access unit, a base station controller, or a node on a network. The terminal may include a UE (User Equipment), an MS (Mobile Station), a cellular phone, a smartphone, a computer, or a multimedia system capable of performing a communication function. In addition, the embodiments of the present disclosure may be applied to other communication systems having a similar technical background or channel type to the embodiments of the present disclosure described below. In addition, the embodiments of the present disclosure may be applied to other communication systems through some modifications without significantly departing from the scope of the present disclosure at the discretion of a person having skilled technical knowledge.

[0031] 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.

[0032] 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.

[0033] According to embodiments proposed in the present disclosure, a method and device for transmitting a control signal using a User Plane in order to use a service provided by a User Plane Function (UPF) are provided.

[0034] FIG. 1 illustrates the structure of a 5G network according to one embodiment of the present disclosure.

[0035] Referring to Figure 1, the network entities or network nodes that constitute the 5G network are described as follows.

[0036] (R)AN ((Radio) Access Network) is an entity that performs wireless resource allocation of a terminal, and may be at least one of an eNode B, Node B, BS (Base Station), NG-RAN (NextGeneration Radio Access Network), 5G-AN, a wireless access unit, a base station controller, or a node on a network.

[0037] A terminal may include a UE (User Equipment), an NG UE (NextGeneration UE), an MS (Mobile Station), a cellular phone, a smartphone, a computer, or a multimedia system capable of performing communication functions. Furthermore, while the embodiments of the present disclosure will be described below using a 5G system as an example, the embodiments of the present disclosure may also be applied to other communication systems with similar technical backgrounds. Furthermore, the embodiments of the present disclosure may be applied to other communication systems with some modifications, as determined by a person skilled in the art, without significantly departing from the scope of the present disclosure.

[0038] As wireless communication systems evolve from 4G to 5G, 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, or a network resource.

[0039] 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.

[0040] The Access and Mobility Management Function (AMF) may be a network function that manages the access and mobility of a terminal (UE). For example, AMF may perform network functions such as registration, connection, reachability, mobility management, access verification, authentication, and mobility event generation.

[0041] The Session Management Function (SMF) may be a network function that manages the Packet Data Network (PDN) connection provided to the 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 through the establishment, modification, and release of sessions and the maintenance of tunnels between the UPF and the RAN required for this; allocation and management of the UE's Internet protocol (IP) address; selection and control of the user plane; control of traffic processing in the UPF; and control of the collection of charging data.

[0042] PCF (Policy Control Function) may be a network function that applies a mobile carrier's service policy, charging policy, and PDU Session policy to a terminal.

[0043] Unified Data Management (UDM) can be a network function that stores subscriber information. For example, UDM can perform functions such as generating authentication information for 3GPP security, processing user identifiers (user IDs), managing a list of network functions supporting UEs, and managing subscription information.

[0044] The Network Exposure Function (NEF) may provide information about a terminal to a server outside the 5G network. Additionally, NEF may provide the ability to store information necessary for 5G network services in the UDR.

[0045] The User Plane Function (UPF) may function as a gateway that transmits user data (PDU) to the Data Network (DN). More specifically, the UPF may process data so that it can transmit data transmitted by a terminal to an external network or transmit data received from an external network to the terminal. For example, the UPF may perform network functions such as serving as an anchor between radio access technologies (RATs), packet routing and forwarding, packet inspection, user plane policy application, traffic usage report generation, and buffering.

[0046] NRF (Network Repository Function) can perform the function of discovering NF.

[0047] AUSF (Authentication Server Function) can perform terminal authentication in 3GPP access networks and non-3GPP access networks.

[0048] NSSF (Network Slice Selection Function) can perform the function of selecting a Network Slice Instance provided to a terminal.

[0049] DN (Data Network) can be a data network where terminals transmit and receive data to use network operator services or third-party services.

[0050] Additionally, terms used in this disclosure may be defined as follows.

[0051] ProSe (ProSe Service or Proximity-based Service) (proximity service) can refer to a service that enables discovery between physically close devices, direct communication between them, communication via a base station, or communication via a third-party device. In this case, user plane data can be exchanged via a direct data path without going through the core network.

[0052] A ProSe-enabled UE (proximity service-enabled terminal) may refer to a UE that supports ProSe discovery and / or ProSe communication.

[0053] ProSe UE-to-Network Relay (Proximity Service UE-to-Network Relay) is a ProSe-enabled UE, and can refer to a form of relay that operates as a communication relay between a ProSe-enabled UE and a network.

[0054] ProSe UE-to-UE Relay (Proximity Service UE-to-UE Relay) is a ProSe-enabled UE and can refer to a form of relay that operates as a proximity service communication relay between ProSe-enabled UEs.

[0055] ProSe Discovery (proximity service discovery) may refer to the process by which a ProSe-enabled UE identifies whether there is another ProSe-enabled UE or ProSe relay providing a nearby service.

[0056] FIG. 2 illustrates a 5G ProSe (Proximity based Services) UE-to-Network Relay structure supporting multiple hops according to one embodiment of the present disclosure.

[0057] Referring to FIG. 2, a 5G ProSe Remote UE, a 5G ProSe UE-to-UE Relay, and a 5G ProSe UE-to-Network Relay may be 5G ProSe enabled UEs. In addition, the 5G ProSe Remote UE may communicate with the NG-RAN (or network) in a multiple hops environment using the 5G ProSe UE-to-UE Relay and the 5G ProSe UE-to-Network Relay. The 5G ProSe UE-to-UE Relay and the 5G ProSe UE-to-Network Relay may provide a data relay service to enable the 5G ProSe Remote UE to communicate with the network in a multiple hops environment. In addition, the 5G ProSe enabled UEs (e.g., including at least one of the 5G ProSe Remote UE, the 5G ProSe UE-to-UE Relay, or the 5G ProSe UE-to-Network Relay) may use the PC5 interface to transmit data and signaling. A 5G ProSe enabled UE and an NG-RAN (or network) can use the Uu interface for user data transmission. Hereinafter, in the embodiments of the present disclosure, a terminal or relay may refer to a 5G ProSe enabled UE. In addition, a 5G ProSe enabled UE may refer to at least one of a 5G ProSe Remote UE, a 5G ProSe UE-to-UE Relay, or a 5G ProSe UE-to-Network Relay. Of course, the present invention is not limited to the above examples, and may include other devices for performing 5G ProSe communication, although not included in the above examples.

[0058] FIG. 3 illustrates a 5G ProSe UE-to-UE Relay structure supporting Multiple Hops according to one embodiment of the present disclosure.

[0059] Referring to FIG. 3, a 5G ProSe End UE and a 5G ProSe UE-to-UE Relay are 5G ProSe enabled UEs, and the 5G ProSe End UE can communicate with the counterpart 5G ProSe End UE using the 5G ProSe UE-to-UE Relay. The 5G ProSe UE-to-UE Relay can provide a data relay service to enable 5G ProSe End UEs to communicate. In addition, 5G ProSe enabled UEs (e.g., 5G ProSe End UE and 5G ProSe UE-to-UE Relay) can use the PC5 interface to transmit data and signaling.

[0060] FIG. 3 illustrates a structure that supports multiple hops where at least one 5G ProSe UE-to-UE Relay can be used for data transmission.

[0061] In the present disclosure, a method for supporting reliable communication for a 5G ProSe enabled UE that communicates using a 5G ProSe UE-to-UE Relay or a 5G ProSe UE-to-Network Relay in ProSe communication supporting a multiple hops environment can be proposed.

[0062] FIG. 4 illustrates an example of a communication interruption situation that may occur in ProSe communication supporting Multiple Hops according to one embodiment of the present disclosure.

[0063] Referring to Figure 4, if communication infrastructure is destroyed by a disaster such as an earthquake or fire, communication may become impossible. In this case, ProSe can be a method to enable communication using user terminals without the destroyed infrastructure (e.g., base stations). Because terminals operate on batteries, their transmission distances can be much shorter than those of base stations. Therefore, to communicate with a distant terminal, a terminal can relay data using nearby terminals. This type of communication, where a terminal relays data using nearby terminals to communicate with a distant terminal, is referred to as multiple-hop communication. However, because communication occurs across multiple terminals, reliable communication can be difficult due to issues with the communication links between each hop. As shown in Figure 4, communication may be interrupted when the terminal's battery is completely depleted, causing the terminal to power off. Furthermore, communication may be interrupted when the distance between two terminals exceeds the transmission distance of the terminals, or when obstacles such as cars or buildings interfere with communication. Accordingly, in this disclosure, a method for reliably performing ProSe communication based on multiple hops can be proposed.

[0064] The present disclosure may be applied to a communication method (e.g., ProSe communication) using a 5G ProSe UE-to-UE Relay or a 5G ProSe UE-to-Network Relay, and may be applied to Model A and Model B methods, which are relay discovery methods. In this case, Model A may refer to a discovery method in which a relay transmits an Announcement message, and Model B may refer to a discovery method in which an end UE or a remote UE transmits a Solicitation message.

[0065] The present disclosure can support multiple transmission paths for reliable communication. For example, when searching for a data path, a terminal can perform a multi-path search according to service requirements, and store and / or maintain the searched multi-paths to use alternative paths when the currently used path is disconnected.

[0066] The present disclosure can support multiple data transmissions for reliable communication. For example, a terminal can transmit the same data multiple times according to service requirements.

[0067] The present disclosure can support flooding, which transmits data directly without establishing a data transmission path. Depending on service requirements, this method can skip the process of searching for a data transmission path and transmit data to all terminals. However, flooding can cause network congestion or excessive traffic, and can drain the batteries of many terminals. Therefore, flooding data transmission can be strictly limited and can only be used in extremely urgent situations (e.g., earthquakes, tsunamis, large-scale fires, etc.).

[0068] FIG. 5 illustrates a procedure for a 5G ProSe enabled UE to search for a data path to transmit data according to an embodiment of the present disclosure.

[0069] Referring to FIG. 5, the present embodiment can be described based on a scenario of searching for a 5G ProSe UE-to-UE Relay using Model B.

[0070] The 5G ProSe End UE that initiates the 5G ProSe UE-to-UE Relay discovery may be referred to as the Discoverer 5G ProSe End UE. The Discoverer's counterpart UE may be referred to as the Discoveree 5G ProSe End UE. In a multiple-hop environment, the 5G ProSe UE-to-UE Relay Discovery Solicitation message may include additional parameters in addition to the existing parameters.

[0071] The existing parameters may be referred to as the 5G ProSe UE-to-UE Relay Discovery parameter group. The newly added parameters for multi-hop may be referred to as the Multiple PC5 hops parameter group. Of course, the above names are only examples, and other names may be used. Furthermore, the distinction between existing and additional parameters may not be made.

[0072] The existing parameters may include at least one of Type of Discovery Message, RSC (Relay service code), User Info ID (discoverer), User Info ID (discoveree), Source Layer-2 ID, or Destination Layer-2 ID.

[0073] Additional parameters may include at least one of User Info ID (Relay), Hop Limits, Hop Counts, Degree of Mobility, Status of Battery, Status of Load, Original Source Layer-2 ID, Num. of Duplicated, or List of Source Layer-2 ID(s).

[0074] The Hop Limits value can limit the number of hops a relayed message can travel. Hop Limits can prevent messages from being relayed throughout the network, causing network congestion. Furthermore, since the distance to the appropriate Discoveree 5G ProSe End UE may vary for each RSC (e.g., service), Hop Limits can be adjusted to search for an appropriate Discoveree 5G ProSe End UE. Hop Limits can be determined by the ProSe Application Server and network policies, but can also be manually determined by authorized personnel depending on field conditions (e.g., disaster situations). Furthermore, Hop Limits manually determined by authorized personnel may override values ​​determined by the ProSe Application Server and network policies. Hop Limits can be assigned different values ​​depending on the RSC and field conditions. For example, a service used in a minor disaster situation, such as a traffic accident, may be assigned a small Hop Limits value, while a disaster situation that occurs over a large area, such as an earthquake, may be assigned a large Hop Limits value. Additionally, if the disaster area is a narrow, low-density area like an island, a small Hop Limits value may be assigned, while if it is a large, high-density area like a metropolis, a larger Hop Limits value may be assigned. Furthermore, the Discoverer 5G ProSe End UE may transmit the initial 5G ProSe UE-to-UE Relay Discovery Solicitation message using a Hop Limits value greater than the Min. value to avoid network congestion.Alternatively, if the Discoverer 5G ProSe End UE does not receive a 5G ProSe UE-to-UE Relay Discovery Response message for a specified time (Timer), the RSC may retransmit the Hop Limits message by setting the value between the Min. value and the Max. value, or to the Max. value, depending on the disaster scene situation. In addition, the Hop Limits may be manually retransmitted by an authorized person to a value greater than the Max. value depending on the disaster scene situation (e.g., disaster type, area size, urgency, etc.). Of course, the present invention is not limited to the above example, and the Hop Limits value may be determined by considering multiple situations.

[0075] Hop Counts is a value that increases with each hop, indicating the number of hops a Solicitation message has traveled to reach the Discoveree 5G ProSe End UE. Hop Counts can be used later when the Discoveree 5G ProSe End UE receives a Solicitation message delivered via multiple paths, determining which path to use for the message.

[0076] The Degree of Mobility, Status of Battery, and Status of Load values ​​are values ​​that are entered only by the 5G ProSe UE-to-UE Relay and can be used to maintain a stable overall path when establishing a relay path between the Discoverer 5G ProSe End UE and the Discoveree 5G ProSe End UE. The Degree of Mobility can be a value indicating the mobility of the Relay (e.g., how mobile the Relay is). The Status of Battery can indicate the available battery capacity of the Relay. Since the Relay is also a mobile device, it can be powered by the battery. The Status of Load can indicate the load of the Relay Connectivity Service that the Relay is processing. Since each Relay has a different location and the types and number of connectivity services that it can support, the load that each Relay processes can vary. The above-described information (e.g., Degree of Mobility, Status of Battery, and Status of Load) can be used as basis information for determining which path to select when the discoveree 5G ProSe End UE receives a Solicitation message transmitted through multiple paths. For example, in the case of a path composed of highly mobile relays, frequent relay reselection may occur due to relay movement. In addition, in the case of a path composed of relays with low battery capacity, relay reselection may be required due to relay power-off. Of course, the present invention is not limited to the above examples, and other parameters may be added or replaced in addition to the parameters for the above-described decision.

[0077] The Original Source Layer-2 ID value may be used by Relays to prevent duplicate relaying of Solicitation messages sent by the same Discoverer. The Original Source Layer-2 ID value may be the value assigned to the Source Layer-2 ID (e.g., the Discoverer's Source Layer-2 ID value) within the 5G ProSe UE-to-UE Relay Discovery parameter group by the Relay that first received the Solicitation message from the Discoverer. Subsequent Relays can perform relaying without changing the Original Source Layer-2 ID value.

[0078] The Num. of Duplicated value can be set to search for multiple paths when searching for a data path. Terminals can use the Original Source Layer-2 ID value to prevent network congestion caused by the duplication of a previously transmitted Solicitation message. At this time, if the Num. of Duplicated value is set, even if the terminal has transmitted a Solicitation message, if the Num. of Duplicated value is not '0', the value can be reduced by 1, reset, and the Solicitation message can be retransmitted. If the Num. of Duplicated value is '0', the terminal may not retransmit the Solicitation message.

[0079] The List of Source Layer-2 ID(s) may be a list of Layer-2 ID(s) of Relays that forwarded the Solicitation message. The List of Source Layer-2 ID(s) may indicate which Relays comprise the data path.

[0080] Referring back to FIG. 5, the 5G ProSe UE-to-UE Relay Discovery Solicitation message transmission process can be described. The Discoverer UE can generate and transmit a 5G ProSe UE-to-UE Relay Discovery Solicitation message to communicate with the Discoveree UE using one or more 5G ProSe UE-to-UE Relays. The parameter values ​​of the 5G ProSe UE-to-UE Relay Discovery parameter group (including at least one of the parameters below) in the 5G ProSe UE-to-UE Relay Discovery Solicitation message can be set as follows.

[0081] Type of Discovery Message: 5G ProSe UE-to-UE Relay Discovery Solicitation

[0082] User Info ID: User Info ID of discoverer

[0083] User Info ID: User Info ID of discoveree

[0084] RSC

[0085] Source Layer-2 ID: assigned by discoverer

[0086] Destination Layer-2 ID: default destination Layer-2 ID

[0087] The parameter values ​​of the Multiple PC5 hops parameter group (including at least one of the parameters below) in the 5G ProSe UE-to-UE Relay Discovery Solicitation message can be set as follows.

[0088] User Info ID: User Info ID of Relay

[0089] Hop Limits: Value based on the parameter description above

[0090] Hop Counts: 0

[0091] Degree of Mobility: Relay only (End UE setting is also not excluded)

[0092] Battery Status: Relay only (end UE setting is not excluded)

[0093] Status of Load: Relay only (end UE setting is not excluded)

[0094] Original Source Layer-2 ID: Set only Relay

[0095] Num. of Duplicated

[0096] List of Source Layer-2 ID(s)

[0097] The Solicitation message transmitted by the Discoverer UE can be received by one or more Relays located nearby. Since the Destination Layer-2 ID of the Solicitation message is set to default, all Relays can receive the Solicitation message. After receiving the Solicitation message, the Relay can check the RSC value in the message. If the Relay is an RSC providing connectivity services, the Relay can modify and retransmit the received 5G ProSe UE-to-UE Relay Discovery Solicitation message. In this case, if the Relay is a one-hop Relay from the Discoverer, the Relay can modify the message as follows.

[0098] The 5G ProSe UE-to-UE Relay Discovery parameter group parameters can be as follows, but are not limited to the examples below.

[0099] Type of Discovery Message: 5G ProSe UE-to-UE Relay Discovery Solicitation

[0100] User Info ID: User Info ID of discoverer

[0101] User Info ID: User Info ID of discoveree

[0102] User Info ID: User Info ID of Relay

[0103] RSC

[0104] Source Layer-2 ID: assigned by Relay

[0105] Destination Layer-2 ID: default destination Layer-2 ID

[0106] The Multiple PC5 hops parameter group parameters can be as follows, but are not limited to the examples below.

[0107] Hop Limits: Received Hop Limits - 1

[0108] Hop Counts: Received Hop Counts + 1

[0109] Degree of Mobility: Degree of Mobility of Relay

[0110] Status of Battery: Status of Battery of Relay

[0111] Status of Load: Status of Load of Relay

[0112] Original Source Layer-2 ID: Source Layer-2 ID of Discoverer

[0113] Num. of Duplicated: value (if it is a duplicated relay, value - 1)

[0114] List of Source Layer-2 ID(s): ID (add your own Source Layer-2 ID)

[0115] If you have a Discoverer and a two-hop Relay, you can modify the message as follows:

[0116] The 5G ProSe UE-to-UE Relay Discovery parameter group parameters can be as follows, but are not limited to the examples below.

[0117] Type of Discovery Message: 5G ProSe UE-to-UE Relay Discovery Solicitation

[0118] User Info ID: User Info ID of discoverer

[0119] User Info ID: User Info ID of discoveree

[0120] User Info ID: User Info ID of Relay

[0121] RSC

[0122] Source Layer-2 ID: assigned by Relay

[0123] Destination Layer-2 ID: default destination Layer-2 ID

[0124] The Multiple PC5 hops parameter group parameters can be as follows, but are not limited to the examples below.

[0125] Hop Limits: Received Hop Limits - 1

[0126] Hop Counts: Received Hop Counts + 1

[0127] Degree of Mobility: Existing List of Degree of Mobility of Relay, own Degree of Mobility of Relay

[0128] Status of Battery: Existing List of Status of Battery of Relay, own Status of Battery of Relay

[0129] Status of Load: Existing List of Status of Load of Relay, own Status of Load of Relay

[0130] Original Source Layer-2 ID: Source Layer-2 ID of Discoverer (no change)

[0131] Num. of Duplicated: value (if it is a duplicated relay, value - 1)

[0132] List of Source Layer-2 ID(s): ID (add your own Source Layer-2 ID)

[0133] A relay that receives a Solicitation message including an Original Source Layer-2 ID can determine whether the received Solicitation message is a duplicate message based on at least one of the Discoverer User Info ID, RSC, or Original Source Layer-2 ID values. If it is a duplicate message, the relay can determine whether to retransmit the Solicitation message further using the Num. of Duplicates value. If the Num. of Duplicates value is '0', the relay may not retransmit the Solicitation message further. In this case, the relay may immediately retransmit the Solicitation message it received first, or discard the duplicated messages received thereafter. Alternatively, the relay may consider at least one of the Hop Counts, the relay's mobility, battery, or load status among the duplicated messages received during a certain period of time to determine whether to retransmit (or discard the duplicated messages received thereafter). Additionally, the Relay can also choose whether to retransmit a Solicitation message (or discard a duplicated message received later) based on the received signal strength. For example, in Fig. 5, the first received message can be retransmitted according to the time order of the arrived messages, and the duplicated message received later can be discarded. If the Num. of Duplicated value is greater than or equal to '1', the Relay can decrease the Num. of Duplicated value by '1' and reset the duplicated message with the new value (for example, if the Num. of Duplicated value is 2, it can be reset to 1) and further retransmitted.As described above, the Relay can establish multiple data paths through additional retransmissions. The duplicated message may not be retransmitted further because the Hop Limits value becomes 0 in the last Relay. The Discoveree 5G ProSe End UE can receive the Solicitation message through multiple paths. The Discoveree 5G ProSe End UE that receives the Solicitation message through multiple paths can check the RSC value and User Info ID (e.g., Discoveree) value in the Solicitation message. The Discoveree 5G ProSe End UE can determine the communication path with the Discoverer UE based on the RSC value and User Info ID (Discoveree) value of the checked Solicitation message. For example, the Discoveree 5G ProSe End UE may consider at least one of Hop Counts, Degree of Mobility, Status of Battery, or Status of Load to determine the communication path with the Discoverer UE. In addition, the Discoveree 5G ProSe End UE may also consider the order in which the messages arrived or the radio status with the Relay of the last hop. The example in FIG. 5 illustrates an operation in which a Discoveree 5G ProSe End UE selects a path with the shortest Hop Counts based on the Hop Counts value.

[0134] Paths for data communication between 5G ProSe End UEs can be searched through multiple different relays. Terminals (e.g., 5G ProSe End UEs) can select one of the searched paths to transmit and / or receive data. However, since the currently used data path may be disconnected for various reasons, the terminals (e.g., 5G ProSe End UEs) can store the multiple searched data transmission paths in the form of a table, as shown below. However, the configurations in Table 1 and the configurations included in Table 1 are merely examples and are not limited to the configurations in Table 1.

[0135]

[0136] Path Number may be the index number of the data transmission path searched.

[0137] List of Relays can be a list of Layer-2 IDs of Relays that transmit data on the data path.

[0138] Common Relays may be the Layer-2 ID of a common Relay that is also included in other routes.

[0139] Priority can be a value calculated by considering at least one of the number of hops in the path, degree of mobility, status of battery, or status of load, and Priority can be recalculated by the score value.

[0140] To increase data transmission reliability, a terminal may transmit the same data using two or more data transmission paths. For example, the terminal may select a path for data transmission by considering at least one of the priorities and common relays between the multiple data transmission paths. For example, the terminal may select the path with the highest priority (e.g., Path Number 1) or the path with the fewest common relays (e.g., Path Number 4) among the multiple data transmission paths. As another example, the terminal may select Path Number 3 as the data transmission path by considering both the priorities and common relays among the multiple data transmission paths. Of course, the present invention is not limited to the above example, and a path with a lower priority may also be selected as the data transmission path.

[0141] Figure 6 illustrates a scenario in which identical data is redundantly transmitted via multiple data transmission paths according to one embodiment of the present disclosure. Here, redundant transmission may refer to a method in which identical data is simultaneously transmitted via multiple data transmission paths. However, simultaneous transmission is merely an example and is not necessarily limited to simultaneous transmission.

[0142] Referring to FIG. 6, whether data is transmitted redundantly using multiple data transmission paths can be determined by service (e.g., RSC) requirements. For example, FIG. 6 illustrates a terminal (e.g., a 5G ProSe End UE) transmitting the same data three times using three discovered data transmission paths. As long as at least one of the transmission paths is not disconnected, the data can be transmitted to the other terminal.

[0143] FIG. 7 illustrates data transmission in a flooding manner that transmits data directly without searching for a data path according to one embodiment of the present disclosure.

[0144] Referring to FIG. 7, a terminal (e.g., a source 5G ProSe End UE) can transmit data in a flooding format according to the requirements of a service (e.g., RSC). For flooding, a data transmission message can include a flooding indication and data to be transmitted. The terminal can transmit data by setting the destination User Info ID to the ID of the terminal to be transmitted or to all terminals. The terminal can also reduce network congestion by adding the Hop Limits and Num. of Duplicated fields. In FIG. 7, there are two ways to handle duplicated messages. If a duplicated message is transmitted through different paths, the duplicated message may be retransmitted. However, a duplicated message directly exchanged between two relays may not be retransmitted.

[0145] Figure 8 illustrates the structure of a terminal according to an embodiment of the present disclosure.

[0146] A terminal according to one embodiment of the present disclosure may include a processor (820) that controls the overall operation of the terminal, a transceiver (800) including a transmitter and a receiver, and a memory (810). Of course, the present invention is not limited to the above example, and the terminal may include more or fewer components than those illustrated in FIG. 8.

[0147] According to one embodiment of the present disclosure, the transceiver (800) 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 (800) can receive signals via a wireless channel, output them to the processor (820), and transmit the signals output from the processor (820) via the wireless channel.

[0148] According to one embodiment of the present disclosure, the processor (820) can control the terminal to perform any one of the operations described above. Meanwhile, the processor (820), the memory (810), and the transceiver (800) 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 (820) and the transceiver (800) can be electrically connected. In addition, the processor (820) can be an Application Processor (AP), a Communication Processor (CP), a circuit, an application-specific circuit, or at least one processor.

[0149] According to one embodiment of the present disclosure, the memory (810) can store data such as basic programs, application programs, and setting information for the operation of the terminal. In particular, the memory (510) provides the stored data upon request of the processor (820). The memory (510) 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 (810). In addition, the processor (820) can perform the above-described embodiments based on a program for performing the above-described embodiments of the present disclosure stored in the memory (510).

[0150] FIG. 9 illustrates the structure of a base station or network entity according to an embodiment of the present disclosure.

[0151] A network entity according to one embodiment of the present disclosure may include a processor (920) that controls the overall operation of the network entity, 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 base station or network entity may include more or fewer components than those illustrated in FIG. 9.

[0152] According to one embodiment of the present disclosure, the transceiver (900) can transmit and receive signals with at least one of another base station (or other network entities) or terminal. The signals transmitted and received with at least one of the other base station (or other network entities) or terminal may include control information and data.

[0153] According to one embodiment of the present disclosure, the processor (920) can control a network entity to perform any one of the operations described above. Meanwhile, the processor (920), the memory (910), and the transceiver (900) 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 (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.

[0154] 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 a network entity. 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).

[0155] 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.

[0156] 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).

[0157] 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.

[0158] 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.

[0159] These programs (software modules, software) may be stored in a non-volatile memory including random access memory, flash memory, read only memory (ROM), electrically erasable programmable read only memory (EEPROM), magnetic disc storage devices, compact disc ROMs (CD-ROMs), digital versatile discs (DVDs) or other forms of optical storage devices, magnetic cassettes, or may be stored in a memory configured as a combination of some or all of these. In addition, each configuration memory may include multiple copies.

[0160] 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.

[0161] 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.

[0162] Meanwhile, although the detailed description of the present disclosure has described specific embodiments, it is obvious that various modifications are possible without departing from the scope of the present disclosure. Therefore, the scope of the present disclosure should not be limited to the described embodiments, but should be determined not only by the scope of the following claims but also by equivalents of the scope of the claims. In other words, it will be apparent to those skilled in the art that other modifications based on the technical idea of ​​the present disclosure are possible. In addition, each of the above embodiments can be combined and operated with each other as needed. For example, parts of the methods proposed in the present disclosure can be combined with each other to operate a base station and a terminal. In addition, although the above embodiments have been presented based on a 5G, NR system, other modifications based on the technical idea of ​​the above embodiments can be implemented with other systems such as LTE, LTE-A, and LTE-A-Pro systems.

[0163] 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 relay terminal of a wireless communication system, A step of receiving a first message for discovery for a second terminal from a first terminal; and A step of transmitting a second message to a second relay terminal based on the first message, The above first terminal, the second terminal, the first relay terminal, and the second relay terminal are terminals that support ProSe (proximity based services). A method, wherein the first message includes first information for a relay service and second information for a multi-hop relay.

2. In paragraph 1, A method according to claim 1, wherein the first information includes at least one of the type of the first message, information about the service, information about the first terminal, information about the second terminal, identification information of the first relay terminal, or identification information of the second relay terminal.

3. In paragraph 1, The second information includes at least one of a limit value of the number of hops, a hop count, a number of repetitions of the first message, status information of at least one relay terminal including the first relay terminal, an identifier of the at least one relay terminal, or a list of the at least one relay terminal. A method, wherein at least one relay terminal is a terminal located on a transmission path of the first message.

4. In paragraph 3, A method, wherein the status information of at least one relay terminal includes at least one of information regarding the degree of mobility, battery status information, or data status information.

5. In paragraph 2, A method wherein the duplication of the first message is based on information about the second terminal, information about the service, and identification information of the first relay terminal.

6. In the third paragraph, the method, A method further comprising the step of identifying transmission of the second message based on the number of repetitions of the first message.

7. In paragraph 6, the method, If the number of duplicates of the first message is 0, a step of discarding at least one of the duplicated first messages; and A method further comprising the step of generating the second message if the number of repetitions of the first message is not 0.

8. In paragraph 1, The data reception paths from the second terminal are based on the first information and the second information, A method wherein the above data reception paths include candidate data reception paths.

9. In the first relay terminal of the wireless communication system, Transmitter and receiver; and At least one control unit connected to the above transceiver unit, At least one of the above control units: Receive a first message for discovery for a second terminal from the first terminal, Based on the above first message, a second message is set to be transmitted to the second relay terminal, The above first terminal, the second terminal, the first relay terminal, and the second relay terminal are terminals that support ProSe (proximity based services). A first relay terminal, wherein the first message includes first information for a relay service and second information for a multi-hop relay.

10. In paragraph 9, A first relay terminal, wherein the first information includes at least one of the type of the first message, information about the service, information about the first terminal, information about the second terminal, identification information of the first relay terminal, or identification information of the second relay terminal.

11. In paragraph 9, The second information includes at least one of a limit value of the number of hops, a hop count, a number of repetitions of the first message, status information of at least one relay terminal including the first relay terminal, an identifier of the at least one relay terminal, or a list of the at least one relay terminal. A first relay terminal, wherein at least one of the relay terminals is a terminal located on a transmission path of the first message.

12. In paragraph 11, A first relay terminal, wherein the status information of at least one relay terminal includes at least one of information regarding the degree of mobility, battery status information, or data status information.

13. In paragraph 10, A first relay terminal, wherein whether the first message is duplicated is based on information about the second terminal, information about the service, and identification information of the first relay terminal.

14. In paragraph 11, at least one control unit: A first relay terminal further configured to identify transmission of the second message based on the number of repetitions of the first message.

15. In paragraph 14, at least one control unit: If the number of duplicates of the first message is 0, it is further set to discard at least one of the duplicated first messages, and A first relay terminal further configured to generate the second message if the number of repetitions of the first message is not 0.

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