Direct communication session management method and device in wireless communication system

Abstract

A method and user equipment for performing device-to-device communication by user equipment in a wireless communication system are provided. The method for performing device-to-device communication in a wireless communication system performed by the user equipment may include: receiving information about a data path from a network entity; based on the information about the data path, determining the data path for device-to-device communication as a path through a Uu interface or a path through a PC5 interface; and performing device-to-device communication via the determined data path.

Description

Technical Field

[0001] The present disclosure relates to methods and apparatus for providing Proximity Based Services (ProSe) to user equipment. Background Art

[0002] In order to meet the growing demand for wireless data services after the commercialization of the fourth generation (4G) communication system, considerable efforts have been made to develop pre-fifth generation (5G) communication systems or 5G communication systems. This is one reason why "5G communication systems" or "pre-5G communication systems" are also called "beyond 4G network communication systems" or "post-long term evolution (LTE) systems."

[0003] In order to achieve high data rates, 5G communication systems are being developed to be implemented in ultra-high frequency bands (millimeter waves (mmWave)), such as the 60 GHz band. In order to reduce the path loss of radio waves in such ultra-high frequency bands and increase the transmission distance of radio waves in 5G communication systems, various technologies have been discussed and are being studied, such as: beamforming, massive multiple-input multiple-output (MIMO), full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and large antennas.

[0004] In order to improve the system network for 5G communication systems, various technologies have been developed, such as evolved small cells, advanced small cells, cloud radio access networks (Cloud-RAN), ultra-dense networks, device-to-device communication (D2D), wireless backhaul, mobile networks, cooperative communication, coordinated multi-point (CoMP), and interference cancellation.

[0005] In addition, for 5G systems, other technologies have been developed, for example, hybrid frequency shift keying (FSK) and quadrature amplitude modulation (QAM) (FQAM) and sliding window superposition coding (SWSC) which are advanced coding modulation (ACM) schemes, and filter bank multi-carrier (FBMC) which are advanced access schemes, non-orthogonal multiple access (NOMA) and sparse code multiple access (SCMA).

[0006] The Internet has evolved from a human-based connected network where humans create and consume information to the Internet of Things (IoT), in which distributed components (such as objects) exchange information with each other to process information. Internet of Everything (IoE) technology is emerging, in which technologies related to IoT are combined with technologies for processing big data by connecting cloud servers. In order to realize IoT, various technical components are required, such as sensing technology, wired / wireless communication and network infrastructure, service interface technology, security technology, etc. In recent years, technologies including sensor networks for connecting objects, machine-to-machine (M2M) communication, machine type communication (MTC), etc. have been studied. In the IoT environment, smart Internet technology (IT) services can be provided to collect and analyze data obtained from objects connected to each other to create new value in human life. As existing information technology (IT) technologies and various industries merge and combine with each other, IoT can be applied to various fields such as smart homes, smart buildings, smart cities, smart cars or connected cars, smart grids, healthcare, smart appliances, high-quality medical services, etc.

[0007] There are many attempts to apply 5G communication systems to IoT networks. For example, sensor networks, M2M communications, MTC and other related technologies are being implemented by using 5G communication technologies (including beamforming, MIMO, array antennas, etc.). The above-mentioned application of Cloud-RAN as a big data processing technology may be an example of the integration of 5G communication technology and IoT technology.

[0008] Due to the development of the mobile communication system according to the above-mentioned technology, various services have become available, and in particular, a method of enabling a user equipment to directly communicate with another user equipment is required.

[0009] The mobile communication system can provide device-to-device direct communication (ProSe communication, PC5 communication, sidelink communication or device-to-device (D2D) communication) services. In order to provide device-to-device direct communication, a network function (NF) for providing direct communication services is defined, and a protocol between a user equipment (UE) and the NF and a protocol between an application function (AF) and the NF can be defined. In addition, a 5G core network (core network, CN) can be connected to a base station to provide the base station and the user equipment with information required for direct communication. In addition, the user equipment can request the radio resources required for direct communication from the base station, and the base station can allocate the radio resources to the user equipment. Summary of the invention

[0010] Technical issues

[0011] The user equipment may perform device-to-device direct communication (PC5 communication) for exchanging data with other user equipments. Alternatively, the user equipment may perform network communication (Uu communication) through a network (eg, a base station, a 3GPP network through a core network) for exchanging data with other user equipments.

[0012] In the present disclosure, a method for a user equipment to determine a communication path (PC5 communication or Uu communication) and a method for the user equipment to switch a communication path (PC5 to Uu or Uu to PC5) are proposed.

[0013] Technical Solution

[0014] According to an embodiment of the present disclosure, a method for performing device-to-device communication in a wireless communication system performed by a user equipment may include: receiving information about a data path from a network entity; based on the information about the data path, determining the data path used for device-to-device communication as a path through a Uu interface or a path through a PC5 interface; and performing device-to-device communication via the determined data path.

[0015] According to an embodiment of the present disclosure, a user equipment for performing device-to-device communication in a wireless communication system may include: a transceiver; and a processor, which is connected to the transceiver and configured to: receive information about a data path from a network entity; based on the information about the data path, determine the data path for device-to-device communication as a path through a Uu interface or a path through a PC5 interface; and perform device-to-device communication via the determined data path. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A user equipment registration process according to an embodiment of the present disclosure is shown.

[0017] Figure 2 is a sequence diagram illustrating a process in which a 5G core network provides data path information to a user equipment according to an embodiment of the present disclosure.

[0018] Figure 3 is a sequence diagram illustrating a process for switching a data path according to an embodiment of the present disclosure.

[0019] Figure 4 is a sequence diagram illustrating a process for switching a data path according to an embodiment of the present disclosure.

[0020] Figure 5 is a sequence diagram illustrating a process for switching a data path according to an embodiment of the present disclosure.

[0021] Figure 6 is a sequence diagram illustrating a process for switching a data path according to an embodiment of the present disclosure.

[0022] Figure 7 is a block diagram showing a detailed structure of a user equipment according to an embodiment of the present disclosure.

[0023] Figure 8 is a block diagram showing a detailed structure of a base station according to an embodiment of the present disclosure.

[0024] Fig. 9 is a block diagram illustrating the structure of a core network object according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0025] Hereinafter, embodiments of the present disclosure will be described more fully with reference to the accompanying drawings.

[0026] In the description of the embodiments, descriptions of technical contents that are well known in the art to which the present disclosure belongs and are not directly related to the present disclosure will be omitted. This is to clearly convey the main points of the present disclosure without obscuring the main points of the present disclosure by omitting unnecessary descriptions.

[0027] For the same reason, in the accompanying drawings, each component is exaggerated, omitted or schematically shown. In addition, the size of each component does not fully reflect the actual size. Regardless of the figure number, the same or corresponding parts are represented by the same reference numerals.

[0028] The advantages and features of the present disclosure and the methods for achieving the advantages and features will become apparent with reference to the embodiments of the present disclosure described in detail below with reference to the accompanying drawings. However, the present disclosure can be implemented in many different forms and should not be construed as limited to the embodiments set forth herein; on the contrary, these embodiments of the present disclosure are provided so that the present disclosure will be thorough and complete and will fully convey the concepts of the present disclosure to those skilled in the art, and the present disclosure is limited only by the scope of the claims. Throughout the specification, the same reference numerals refer to the same components.

[0029] It will be understood that each box of the flowchart diagram and the combination of boxes in the flowchart diagram can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer or other programmable data processing equipment, so that the instructions run by the processor of the computer or other programmable data processing equipment generate a device for performing the function specified in the flowchart (multiple) box. These computer program instructions can also be stored in a computer-operable or computer-readable memory, which can instruct the computer or other programmable data processing equipment to operate in a specific manner, so that the instructions stored in the computer-operable or computer-readable memory can generate a product including an instruction device for performing the function specified in the flowchart (multiple) box. The computer program instructions can also be loaded on a computer or other programmable data processing equipment so that a series of operating steps are performed on a computer or other programmable data processing equipment, thereby generating a computer-operable process, so that the instructions running on a computer or other programmable data processing equipment can provide steps for implementing the functions specified in one or more boxes of the flowchart.

[0030] In addition, each frame can represent a module, a fragment or part of a code, which includes one or more executable instructions for realizing (multiple) specific logic functions. It should also be noted that in some alternative implementations, the functions mentioned in the frame may not occur in the order given. For example, according to the functions involved, two frames shown in succession can actually be run substantially simultaneously, or these frames can sometimes be run in reverse order.

[0031] The term "unit" or "device" used herein means a software component or a hardware component, such as a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC), and performs a specific function. However, the term "unit" or "device" is not limited to software or hardware. The term "unit" or "device" can be configured to be included in an addressable storage medium, or to reproduce one or more processors. Therefore, according to an embodiment of the present disclosure, the term "unit" or "device" can include, for example, object-oriented software components, class components, and task components, as well as processes, functions, attributes, procedures, subroutines, program code segments, drivers, firmware, microcodes, circuits, data, databases, data structures, tables, arrays, and variables. The functions provided by components and "units" or "devices" can be combined into a smaller number of components and "units" or "devices", or can be further divided into additional components and "units" or "devices". In addition, components and "units" or "devices" can be implemented to operate one or more central processing units (CPUs) in a device or a secure multimedia card. Therefore, according to an embodiment of the present disclosure, the term "unit" or "device" can include one or more processors.

[0032] Hereinafter, the operating principle of the present disclosure will be described with reference to the accompanying drawings. Although the present disclosure is described, when it is considered that the relevant well-known functions or configurations may unnecessarily obscure the essence of the present disclosure, their detailed description may be omitted. In addition, the terms used below are defined in consideration of the functions in the present disclosure, and the terms may have different meanings according to the intentions, habits, etc. of the user or operator. Therefore, the terms should be defined based on the description throughout the specification. In the following, a base station is an entity that assigns resources to user equipment, and may be at least one of a gNode B, an eNode B, a base station (BS), a wireless access unit, a base station controller, or a node on a network. Examples of user equipment may include user equipment (UE), a mobile station (MS), a cellular phone, a smart phone, a computer, or a multimedia system capable of performing communication functions. However, the present disclosure is not limited to the above examples.

[0033] Hereinafter, in the present disclosure, a technology for receiving broadcast information from a base station by a user equipment in a wireless communication system is described. The present disclosure relates to a communication technology and a system thereof for integrating a 5G communication system supporting a higher data rate after a 4G system with IoT technology. The present disclosure can be applied to smart services (e.g., smart homes, smart buildings, smart cities, smart cars or connected cars, healthcare, digital education, retail business, safety and security related services, etc.) based on 5G communication technology and IoT related technology.

[0034] The terms used in the following description referring to broadcast information, terms referring to control information, terms related to communication coverage, terms referring to state changes (e.g., events), and terms referring to network entities, terms referring to messages, terms referring to device components, etc. are examples provided for convenience of description. However, the present disclosure is not limited to the following terms, and other terms with equivalent technical meanings may be used.

[0035] Herein, for convenience of description, some terms and names defined in the 3rd Generation Partnership Project Long Term Evolution (3GPP LTE) standard may be used. However, the present disclosure is not limited by the above terms and names, and can be equally applied to systems conforming to other standards.

[0036] With regard to wireless communication systems, progress is ongoing, from providing only voice-based services in the initial stage to broadband wireless communication systems for providing high-speed and high-quality packet data services, such as communication standards including 3GPP's High Speed ​​Packet Access (HSPA), Long Term Evolution (LTE) or Evolved Universal Terrestrial Radio Access (E-UTRA), LTE-Advanced (LTE-A), LTE-Pro, 3GPP2's High Rate Packet Data (HRPD), Ultra Mobile Broadband (UMB), and IEEE's 802.16e.

[0037] As a representative example of a broadband wireless communication system, the LTE system adopts orthogonal frequency division multiplexing (OFDM) in the downlink (DL) and a single carrier frequency division multiple access (SC-FDMA) method in the uplink (UL). The uplink refers to a wireless link through which a user equipment (UE) or a mobile station (MS) sends data or a control signal to a base station (eNode B or a base station (BS)), and the downlink refers to a wireless link through which a base station sends data or a control signal to a user equipment. In the multiple access method, data or control information is identified for each user by allocating and operating time-frequency resources, on which data or control information will be carried for each user, so that the time-frequency resources do not overlap with each other, that is, so that orthogonality is established.

[0038] As the future communication system after LTE, the 5G communication system needs to be able to freely reflect various demands such as from users and service providers, so services that meet various demands will be supported. The services considered for the 5G communication system include enhanced mobile broadband (eMBB), massive machine type communication (mMTC), and ultra-reliable low latency communication (URLLC).

[0039] According to an embodiment of the present disclosure, eMBB is intended to provide a better data transmission rate than the data transmission rate supported by existing LTE, LTE-A or LTE-Pro. For example, in a 5G communication system, from the perspective of a base station, eMBB should be able to provide a maximum data rate of 20Gbps in the downlink and a maximum data rate of 10Gbps in the uplink. At the same time, it is necessary to provide an increased user-perceived data rate of user equipment. In order to meet the above requirements, it is necessary to improve the transmission / reception technology, including more advanced multiple-input multiple-output (MIMO) transmission technology. In addition, by using a frequency bandwidth wider than 20MHz in a frequency band of 3GHZ to 6GHz or 6GHz or higher, instead of the 2GHz band used by the current LTE, the data transmission rate required by the 5G communication system can be met.

[0040] At the same time, mMTC is considering supporting application services such as the Internet of Things (IoT) in 5G communication systems. In order to effectively provide the Internet of Things, mMTC may need to support large-scale terminal access in the cell, improve terminal coverage, improve battery life, and reduce terminal costs. Since the Internet of Things is attached to a variety of sensors and a variety of devices to provide communication functions, the Internet of Things must support a large number of user equipment in the cell (e.g., 1,000,000 user equipment / km2). In addition, due to the nature of the service, since the user equipment supporting mMTC is likely to be located in a shadow area not covered by the cell (such as the basement of a building), the user equipment may require a wider coverage than other services provided by the 5G communication system. User equipment supporting mMTC should be configured by a low-cost terminal, and because it is difficult to frequently replace the battery of the user equipment, a very long battery life may be required.

[0041] Finally, URLLC is a cellular-based wireless communication service for mission-critical purposes and is used for remote control of robots or machines, industrial automation, unmanned aerial vehicles, remote healthcare, emergency alerts, etc., and provides ultra-low latency and ultra-high reliability communications. For example, URLLC-enabled services need to meet air interface latency of less than 0.5 milliseconds and have 10 -5 Or lower packet error rate requirements. Therefore, for services supporting URLLC, the 5G system will provide a smaller transmission time interval (TTI) than other services, and at the same time, it is necessary to allocate wide resources in the frequency band. However, the above-mentioned mMTC, URLLC and eMBB are only examples of different service types, and the service types applied by the present disclosure are not limited to the above examples.

[0042] The services considered in the above 5G communication system will be provided by integrating with each other based on a framework. That is, for efficient resource management and control, it is preferred that each service is integrated and controlled and transmitted as a system rather than being operated independently.

[0043] In addition, although the embodiments of the present disclosure are described below using LTE, LTE-A, LTE Pro or NR systems as examples, the embodiments of the present disclosure may be applied to other communication systems having similar technical backgrounds or channel types. In addition, the embodiments of the present disclosure may be applied to other communication systems as judged by persons having professional and technical knowledge by making some modifications within the scope that do not obviously deviate from the scope of the present disclosure.

[0044] The terms used in the following description to identify access nodes, terms referring to network entities or NFs (network functions), terms referring to messages, terms referring to interfaces between network entities, terms referring to various identification information, etc. are examples provided for the convenience of description. Therefore, the present disclosure is not limited to the following terms, and other terms with equivalent technical meanings may be used.

[0045] For convenience of description, some terms and names defined in the 3rd Generation Partnership Project Long Term Evolution (3GPP LTE) and the 5th Generation (5G) standards may be used herein. However, the present disclosure is not limited to the terms and names and can be equally applied to systems conforming to other standards.

[0046] At the same time, in the present disclosure, the term "service" can be used interchangeably with a specific communication equipment (or NF) that executes a request from another communication equipment (or NF) (i.e., referring to an NF service), a service provided by a mobile communication operator (i.e., voice service, text service, data service), a communication service through a network (communication through a Uu interface), a direct communication service (communication through a PC5 (side link) interface), or an application layer service provided by an over-the-top (OTT) operator (i.e., messenger service, game service, etc.).

[0047] According to an embodiment of the present disclosure, the 5G core network may be configured with network functions (NFs) such as AMF, SMF, ProSe functions, PCF, NEF, UDM, UPF, and UDR. User equipment (user equipment, terminal, or UE) may access the 5G core network through a base station (RAN, radio access network).

[0048] The access and mobility management function (AMF) is a network function that manages the wireless network access and mobility of user equipment. The session management function (SMF) is a network function that manages the packet data network connection provided to the user equipment. The packet data network connection is called a protocol data unit (PDU) session. The PDU session information may include quality of service (QoS) information, charging information, or packet processing information. The policy control function (PCF) is a network function for applying service policies, charging policies, and policies for PDU sessions to user equipment by a mobile communication operator. Unified data management (UDM) is a network function that stores and manages subscriber information. The network open function (NEF) is a network function that allows access to information for managing user equipment in a 5G network. For example, NEF can access information such as subscriptions to mobility management events of user equipment, subscriptions to session management events of user equipment, requests for session related information, and settings of charging information of user equipment, requests to change PDU session policies of user equipment, etc. NEF is connected to the 5G core network NF to pass information about user equipment to NF, or report information about user equipment to the outside. The application function (AF) can use the services and functions provided by the 5G network through the NEF.

[0049] 5G Radio Access Network (RAN) refers to a base station that provides wireless communication functions to user equipment. 5G-RAN can allocate direct communication radio resources to user equipment. The user plane function (UPF) acts as a gateway for sending packets sent and received by user equipment and is controlled by SMF. UPF is connected to the data network (DN) and performs the function of delivering data packets generated in the 5G system to an external data network. For example, UPF can be connected to a data network connected to the Internet, and data packets sent by user equipment can be routed to the Internet. Unified Data Repository (UDR) is a network function that stores and manages data. For example, UDR can store user equipment subscription information and provide user equipment subscription information to UDM. UDR can store operator policy information and provide operator policy information to PCF. UDR can store network service exposure related information and can provide network service exposure related information to NEF.

[0050] The ProSe function refers to a logical function that performs the operation of a network required to provide proximity services. One or more ProSe functions may exist in a public land mobile network (PLMN) and may be deployed to serve a specific area or to serve certain user equipment. The ProSe function may perform a direct provisioning function that provides the information required for user equipment to use ProSe services. The direct provisioning function refers to a function that supplies information required for a direct discovery function used by neighboring user equipment to directly discover each other or a direct communication function for device-to-device (D2D) direct communication.

[0051] In addition, the ProSe function may perform a function of managing a name or code for direct discovery in order to support a direct discovery function in the user equipment. In addition, the ProSe function may perform a triggering function so that the user equipment may perform the direct discovery function, and may also provide a charging function or a security-related function regarding the use of the ProSe service.

[0052] According to an embodiment of the present disclosure, the ProSe function may be referred to by a name other than the ProSe function, and the functions and operations provided by the ProSe function (e.g., protocols and signaling procedures for communication between user equipment, NF and AF, etc.) may be provided by another NF (e.g., PCF, etc.).

[0053] Each NF defines the services they provide, and the services provided by the NF may be referred to as Npcf, Nsmf, Namf, Nnef services, etc. For example, when the AMF passes session-related messages to the SMF, the AMF may use a service (or API) named Nsmf_PDUSession_CreateSMContext. The ProSe function also defines NF services and may be connected to other NFs. For example, the services provided by the ProSe function may be defined as Nprose services, and the ProSe function may provide services (or APIs) such as Nprose_event_notification.

[0054] The application function (AF) may be an application server (AS) that provides a function of using the ProSe service. That is, the AF may be a ProSe application server or a network control interaction service (NCIS) application server that provides the NCIS service. The ProSe application server or the NCIS application server may operate like the AF of the 3GPP system.

[0055] In the 3GPP system, a special service for NCIS can be provided, which is called NCIS service. NCIS service can refer to a service that enables one or more user equipment to join the NCIS group and share data with each other for interactive games or data sharing. NCIS group can refer to a group of application layers using the same NCIS session. NCIS session can refer to a session in which all user equipment (e.g., user equipment belonging to the same NCIS group) in one of the sessions of the application of each other's NCIS can share background information, status information, update information, etc. That is, all user equipment belonging to an NCIS session can have the same background information, status information and update information. User equipment belonging to the same NCIS group can be close to each other and use device-to-device communication (D2D communication). Or, even if the user equipment belonging to the same NCIS group can communicate through the network when they are far away from each other.

[0056] In addition, public security network technology, such as public security services (or mission-critical services), can be provided in the 3GPP system. The 3GPP system uses public security network technology to provide users with services that enable communications for public security in the event of a disaster. User equipment can use public security network technology based on network communication or direct communication. Even when the network is interrupted, user equipment can send and receive data by using direct communication.

[0057] The user equipment can access the AMF via the base station and exchange control plane signaling messages with the 5G core network. In addition, the user equipment can access the UPF via the base station and exchange data with the data network and the user plane. When exchanging control plane signaling messages with the 5G core network, the application server that provides application layer services to the user equipment can be referred to as AF, and when exchanging user plane data with the user equipment, it can be referred to as DN. In addition, AF and DN can be used interchangeably as names referring to application servers.

[0058] A user equipment supporting direct communication may obtain configuration information for direct communication from a 5G core network (e.g., AMF, PCF, ProSe function, etc.). The user equipment may perform a variety of operations for direct communication (e.g., ProSe mode 1, ProSe mode 2, ProSe mode 3, ProSe mode 4, out-of-coverage operation, in-coverage operation, etc.) based on the configuration information for direct communication obtained from the 5G core network.

[0059] For example, in order to send the message through the PC5 interface, the user equipment can send a message to the base station requesting resource information about which resource to use to send the message, and the base station can select the optimal side link transmission resource based on the current network conditions and reply to the user equipment with the selected resource. Whenever a message is sent, the user equipment can request side link resource information from the base station. Hereinafter, when describing the present disclosure, the method in which the user equipment sends a resource information request message to the base station and receives information about the optimal side link transmission resource from the base station is referred to as mode 3 operation or mode 1 operation. When using LTE wireless technology, it can be referred to as mode 3, and when using NR wireless technology, it can be referred to as mode 1.

[0060] As another example, in order to send a message through the PC5 interface, the user equipment may send a message to the base station requesting resource information using which it can send a message, and the base station may reply to the user equipment with the side link resource pool information available to the user equipment. The user equipment may store the side link resource pool information received from the base station, and whenever a V2X message is sent, the message may be sent by selecting resources from the stored side link resource pool. Optionally, even when the user equipment does not explicitly request resource information from the base station, the base station may notify the user equipment of the side link resource pool information through system information provided to the user equipment, and the user equipment may use the received information for resource selection when sending the V2X message. Hereinafter, when describing the present disclosure, the method in which the user equipment sends a resource information request message to the base station and receives the side link resource pool information from the base station is referred to as operating within the coverage of mode 4 or mode 2. When using LTE wireless technology, it may be referred to as mode 4, and when using NR wireless technology, it may be referred to as mode 2.

[0061] As another example, side link resource information for sending V2X messages may be preconfigured in the user equipment, and the user equipment may send the V2X message by using the preconfigured side link resource information. In this method, communication between the user equipment and the base station may not be necessary. In describing the present disclosure, the method in which the user equipment uses the preconfigured side link resource information is referred to as Mode 4 or Mode 2 out-of-coverage operation. When using LTE wireless technology, the above method may be referred to as Mode 4, and when using NR wireless technology, the above method may be referred to as Mode 2.

[0062] [First embodiment]

[0063] Hereinafter, in the first embodiment of the present disclosure, a service and session continuity mode (service and session continuity mode, hereinafter interchangeably referred to as "SSC mode") for a service using direct communication is defined, and examples of SSC modes applicable to various situations are described. In addition, in the first embodiment of the present disclosure, a process for a user equipment to obtain SSC mode information from a 5G core network is described.

[0064] A user equipment can send and receive data with another user equipment by using direct communication. Direct communication is possible when another user equipment is located within the data transmission range of the user equipment. When another user equipment is located outside the data transmission range of the user equipment, the user equipment cannot send data to other user equipment or receive data from other user equipment by using direct communication. The situation in which data cannot be sent or received as described above can be referred to as a situation in which service and session continuity are not provided. In order to provide service and session continuity, even when another user equipment is located outside the data transmission range of the user equipment, and the user equipment and another user equipment cannot send data to each other or receive data from each other by using direct communication, the user equipment can send data to another user equipment through the network. When the user equipment is able to send or receive data through the network as described above, it can be said that service and session continuity are provided.

[0065] According to an embodiment of the present disclosure, the SSC mode of a service using direct communication may be defined in a variety of ways. For example, in a specific service using direct communication, data may be sent or received only by using direct communication. In this case, when another user equipment is outside the data transmission range of the user equipment, the user equipment cannot send data to or receive data from another user equipment by using direct communication. Hereinafter, in the present disclosure, a mode in which data is sent or received only by direct communication is referred to as ProSe SSC mode 1. Examples of services using ProSe SSC mode 1 may include proximity communication services (e.g., music streaming services by connecting user equipment to a speaker).

[0066] As another example, in a specific service using direct communication, data may be sent or received by using direct communication or network communication. During the execution of a service using direct communication, when another user equipment deviates from the data transmission range of the user equipment, the user equipment may switch the direct communication to the network communication to continuously send or receive data. In this case, the user equipment may disconnect the direct communication connection and establish a network communication connection (break before connect). Hereinafter, in the present disclosure, a mode in which the user equipment disconnects the direct communication connection and establishes a network communication connection to continuously send or receive data is referred to as ProSe SSC mode 2. Examples of services using ProSe SSC mode 2 may include services (e.g., file transfer, etc.) that do not affect the quality of service even if packet loss occurs.

[0067] As another example, in a specific service using direct communication, data may be sent or received by using direct communication or network communication. During the execution of a service using direct communication, the user equipment may switch direct communication to network communication and continuously send or receive data even when another user equipment is within the data transmission range of the user equipment. The user equipment may establish a network communication connection while maintaining a direct communication connection, and disconnect the direct communication connection (first connect and then disconnect). Hereinafter, in the present disclosure, a mode in which, in order to continuously send or receive data, the user equipment establishes a network communication connection while maintaining a direct communication connection, and disconnects the direct communication connection after the network communication connection is established is referred to as ProSe SSC mode 3. Examples of services using ProSe SSC mode 3 may include services that affect the quality of service when packet loss occurs (e.g., voice services, etc.).

[0068] As another example, in a service using direct communication, both direct communication and network communication can be established, and data can be sent or received simultaneously by using direct communication and network communication. When another user equipment is within the data transmission range of the user equipment, the user equipment can send or receive data by using both direct communication and network communication. When another user equipment is outside the data transmission range of the user equipment, the user equipment can send or receive data by using network communication. Hereinafter, in the present disclosure, a mode in which a user equipment sends or receives data by using both direct communication and network communication is referred to as ProSe SSC mode 4. Examples of services using ProSe SSC mode 4 may include services requiring high reliability (e.g., emergency services, etc.). The user equipment can send the same data by using direct communication and network communication. Optionally, the user equipment can send different data from each other by using direct communication or network communication.

[0069] Figure 1A user equipment registration process according to an embodiment of the present disclosure is shown.

[0070] During the registration process, the UE 100 may obtain from the 5G core network 102 information about services that use direct communication and are available to the UE 100 , and information about ProSe SSC modes that are applicable to services that use direct communication available to the UE.

[0071] refer to Figure 1 In operation 110, the UE 100 may perform a registration (registration or attachment) procedure on the network (RAN 101, core network CN 102). The registration request (registration or attachment request) message sent by the UE 100 to the network may include information indicating that the user equipment has ProSe capability.

[0072] The core network 102 (e.g., an NF supporting registration and mobility management regarding the UE 100 (AMF for 5G, MME for 4G)) may process the registration request received from the UE 100 in operation 110, and may determine whether the ProSe function is available for the UE 100, whether the ProSe service is available for the UE 100, whether the ProSe SSC mode of the ProSe service is available for the UE 100, etc. based on the user equipment subscription information.

[0073] Despite Figure 1 Although omitted in the description, the core network 102 (e.g., AMF or MME) may send a registration accept (registration or attach accept) message to the UE 100. The registration accept message sent to the UE 100 may include at least one of the ProSe services available for the UE 100 and the ProSe SSC mode information available for the ProSe services of the UE 100.

[0074] When receiving the Registration Accept message, the UE 100 may store the ProSe service and the ProSe SSC mode information of the ProSe service included in the Registration Accept message, and may use them in a subsequent procedure.

[0075] refer to Figure 1In operation 112, the ProSe function 103 may request an event subscription request from the core network 102 (e.g., a NF supporting registration and mobility management for user equipment (AMF for 5G, MME for 4G)) to obtain location information of the UE 100. In operation 114, the core network 102 may process the received event subscription request. In operation 116, the core network 102 may send a reply message notifying the ProSe function 103 that the event subscription request has been processed. The reply message sent by the core network 102 to the ProSe function 103 may include the current location information of the UE 100.

[0076] In operation 118, the core network 102 may detect (or recognize) that the location of the UE 100 has changed. In operation 120, the core network 102 may notify the ProSe function 103 of the new location information of the UE.

[0077] The ProSe function 103 can be Figure 1 The current location information of the UE 100 may be obtained by the process described in operations 112 to 120. Alternatively, the ProSe function 103 may obtain the location information of the UE directly from the UE 100.

[0078] In addition, the application server (AF) providing the function of using the ProSe service according to an embodiment of the present disclosure may be used in conjunction with the Figure 1 The current location information of UE 100 is obtained in a similar manner to the process described in operations 112 to 120. In this case, the application server can Figure 1 Alternatively, the application server may obtain the location information of the UE directly from the UE 100.

[0079] When using a service that uses direct communication, the user equipment according to an embodiment of the present disclosure may consider the ProSe SSC mode information. For example, when the user equipment intends to use a service in ProSe SSC mode 1, the user equipment may establish a direct communication connection and use the service. Optionally, when the user equipment intends to use a service in ProSe SSC mode 4, the user equipment may establish a direct communication connection and a network communication connection to use the service. Optionally, when the user equipment intends to use a service in ProSe SSC mode 2 or 3, the user equipment may select a communication path by using the method described below with respect to the second embodiment of the present disclosure.

[0080] [Second embodiment]

[0081] In a second embodiment of the present disclosure, a method for determining and selecting a data path for a user equipment to send data to another user equipment or to receive data from another user equipment is described. The data path may include a direct communication path between user equipments and a communication (i.e., network communication) path between user equipments through a network between user equipments. In the following, a data path may refer to a path for a user equipment to send data to another user equipment or to receive data from another user equipment. Figure 2 is a sequence diagram illustrating a process in which a 5G core network provides data path information to a user equipment according to an embodiment of the present disclosure.

[0082] like Figure 1 As shown, according to an embodiment of the present disclosure, the UE 100 may perform a registration process with the network and use direct communication or network communication. The UE 100 may select a data path to send data to another UE 200 or receive data from another UE 200. For example, the UE 100 may select whether to use direct communication, network communication, or both direct communication and network communication to send data to another UE 200 or receive data from another UE 200. According to an embodiment of the present disclosure, an application server (AF) 201 or a core network NF (e.g., ProSe function 103) may determine (or select) a data path.

[0083] Reference Figure 2 In operation 210, the application server 201 may determine a data path between the UE 100 and another UE 200. The application server 201 may determine the data path based on at least one of information received from the UEs 100 and 200 (e.g., information about user equipment participating in the service, current location information of the user equipment, etc.), and information received from the core network 102 (e.g., current location information of the user equipment, etc.). The current location information of the UEs 100 and 200 may include GPS, base station cell ID, geographic display method, etc. However, operation 210 may be omitted, and in operation 214, the UE 100 or the ProSe function 103 may determine the data path.

[0084] In operation 212, the application server 201 may provide service information to the core network of the serving PLMN to which the UE 100 is connected. For example, the application server (AF) 201 may send a ProSe communication request message to the NEF 104. Alternatively, when the application server 110 knows the serving ProSe function information of the UE 100, the application server 110 may directly send a ProSe communication request message to the ProSe function 103. The ProSe communication request message (e.g., a request for creating or updating ProSe communication) sent by the application server 110 to the NEF 104 or the ProSe function 103 may include service information for ProSe communication (e.g., an ID of the UE 100, an ID of another UE 200, a data path selected by the application server 110, etc.).

[0085] According to an embodiment, the NEF 104 that receives the ProSe communication request message from the application server 110 may send the ProSe communication request message to the ProSe function 203. For example, the NEF 104 may store the service information included in the ProSe communication request message received from the application server 110 in the UDR, and the UDR may send a notification message including the stored service information to the ProSe function 103. Alternatively, the NEF 104 may store the service information in the UDR through the UDM, and the UDM may send a notification message including the service information stored in the UDR to the ProSe function 103. Alternatively, the NEF 104 may send the service information directly to the ProSe function 103 through the ProSe communication request message.

[0086] The ProSe function 103 may receive the service information in a variety of ways as described above. In operation 214, the ProSe function 103 having received the service information may determine a data path based on the service information received from the application server 110, a mobile communication operator policy (policy, ProSe policy), and information about the UEs 100 and 200 (e.g., location information of the user equipment, subscription information of the user equipment).

[0087] For example, in operation 212, when the message received by the ProSe function 102 includes information about the data path, the ProSe function 103 may determine to use the data path received from the application server 110 (i.e., the data path determined by the application server 110). Alternatively, the ProSe function 103 may determine the data path based on information (e.g., current location information of the user equipment, etc.) received from the core network 102. For example, based on the information received from the core network 102, the ProSe function 103 may determine to use the data path received from the application server 110, or determine to use a data path different from the data path determined by the application server 110.

[0088] In operation 216 , the ProSe function 103 may reply to the application server 110 with a ProSe communication request response message. The ProSe communication request response message may include information about the data path determined by the ProSe function 103 .

[0089] In operation 218, the ProSe function 103 may send a data transfer request message to the UE 100. The data transfer request message may include information about a data path (e.g., a data path determined by the ProSe function 103) to be used by the UE 100 to transmit data to or receive data from another UE 200. The data transfer request message may be a message requesting the UE 100 to start ProSe communication.

[0090] The ProSe function 103 may send a data transfer request message directly to the UE 100 through the user plane. Alternatively, the ProSe function 103 may send a data transfer request message to the UE 100 through the control plane (ie, the core network NF 102 (AMF for 5G, MME for 4G) and the base station 101).

[0091] In operation 220, the UE 100 may determine a data path with another UE 200 based on the information about the data path received from the ProSe function 103, and establish the determined data path. For example, when the UE 100 receives information about a direct communication path as the information about the data path from the ProSe function 103, the UE 100 may transmit data to or receive data from another UE 200 through the PC5 interface. Alternatively, when the UE 100 receives information about a network communication path as the information about the data path from the ProSe function 103, the UE 100 may transmit data to or receive data from another UE 200 through the Uu interface. Alternatively, when the UE 100 receives both information about a direct communication path and information about a network communication path as the information about the data path from the ProSe function 103, the UE 100 may transmit data to or receive data from another UE 200 through the PC5 interface and / or the Uu interface.

[0092] In operation 222, the UE 100 may reply to the ProSe function 103 with a data transfer response message. The data transfer response message may include information about the data path that the UE 100 has set with the other UE 200. The information about the data path set by the UE 100 with the other UE 200 may be the same as or different from the information about the data path received by the UE 100 from the ProSe function 103 in operation 218. Alternatively, the data transfer response message may include information about a data path setting result indicating whether the data path setting of the data path received by the user equipment from the ProSe function 103 in operation 218 is successful or failed.

[0093] Optionally, the UE 100 according to an embodiment of the present disclosure may determine the data path by itself. For example, the UE 100 may determine the data path based on at least one of the service type to be used, the ProSe SSC mode information linked to the service, or the location of the user equipment. The UE 100 may send data to another UE 200 or receive data from another UE 200 through the determined data path.

[0094] According to the application server, core network NF and user equipment of the embodiment of the present disclosure, a data path for data transmission and reception can be determined. In order to determine the data path, the location of the user equipment, the relative distance between the user equipment and other user equipment, the service type, the ProSe SSC mode, the HPLMN information of each user equipment, etc. can be considered. For example, when the user equipment and another user equipment are subscribed user equipment of the same mobile communication operator, and the relative distance between the user equipment and the other user equipment is close enough to allow direct communication, direct communication can be used. Optionally, when the user equipment and another user equipment are subscribed user equipment of the same mobile communication operator, and the relative distance between the user equipment and the other user equipment is not close enough to allow direct communication, network communication can be used. Optionally, when the user equipment and another user equipment are subscribed user equipment of different mobile communication providers, network communication can be used.

[0095] According to an embodiment of the present disclosure, the application server, the core network NF and the user equipment can switch the data path for data transmission and reception. Figure 2 According to the process shown, the UE 100 can establish a data path for transmitting and receiving data with another UE 200. The UE 100 can transmit data to another UE 200 or receive data from another UE 200 through the established data path.

[0096] According to an embodiment, the UE 100 may transmit data to or receive data from another UE 200 through a direct communication path. When direct communication between the UE 100 and another UE 200 becomes impossible while transmitting and receiving data through the direct communication path (e.g., when the relative distance between the user equipments is not close enough to allow direct communication, when direct communication is not supported at a location to which the user equipments have moved (e.g., when there is no radio frequency for direct communication), etc.), the application server or the core network NF may determine to switch the data path from direct communication to network communication, and may switch the data path from direct communication to network communication through the direct communication path. Figure 2 The process shown sends information about the new data path to the user equipment. Optionally, the user equipment may determine the new data path.

[0097] According to another embodiment, the UE 100 may send data to or receive data from another UE 200 through a network communication path. When direct communication between the UE 100 and another UE 200 becomes possible while sending and receiving data through the network communication path (for example, when the relative distance between the user equipments is close enough to allow direct communication, when direct communication is supported at a location to which the user equipment has moved (for example, when there is a radio frequency for direct communication, etc.)), the application server or the core network NF may determine to switch the data path from the network communication to the direct communication, and may switch the data path from the network communication to the direct communication through the network communication path. Figure 2 The process shown sends information about the new data path to the user equipment. Optionally, the user equipment may determine the new data path.

[0098] Figure 3 is a sequence diagram illustrating a process for switching a data path according to an embodiment of the present disclosure. In detail, Figure 3 A process for switching a direct communication path to a network communication path is shown.

[0099] Reference Figure 3 According to an embodiment of the present disclosure, the UE 100 may determine to switch a data path for transmitting and receiving data with another UE 200 from direct communication to network communication. The UE 100 may establish a network communication path to switch the data path from direct communication to network communication, and may perform a session establishment procedure to establish the network communication path.

[0100] In operation 310, the UE 100 may send a session establishment / modification (PDU session establishment / modification or PDN connection) request message to the network. The session establishment request message sent by the user equipment may include information indicating that the UE 100 has ProSe capability (ProSe capability indication), and may include a data network name (DNN) indicating that the session is to be created. The session that the UE 100 requests the network to create may be a session for network communication between the UE 100 and another UE 200.

[0101] The core network 102 (e.g., NF (SMF for 5G, MME for 4G)) supporting session management for user equipment may process a session establishment request received from the UE 100. Based on information received from the UE 100 (e.g., ProSe indication, DNN, etc.), the core network 102 may know that the received session establishment request message is a session related to direct communication.

[0102] In addition, when user equipment subscription information is required to process a session establishment request, the core network 102 may receive user equipment subscription information from a NF storing subscription information (UDM for 5G, HSS for 4G). The user equipment subscription information may include information about whether ProSe operation (operation for switching direct communication to network communication) is permitted. The SMF or MME may process the session establishment process by using a session establishment request from the user equipment and user equipment subscription information. The ProSe function associated with the session created during the session establishment process may be determined, and the SMF or MME may determine the ProSe function based on one or more of the session establishment request from the user equipment, the information received from the AMF, and the user equipment subscription information. In addition, in order to process the session establishment request, the SMF or MME may receive operator policy information from the PCF or PCRF. In addition, the SMF or MME may pass the information (i.e., user equipment subscription information, operator policy information) to another NF (AMF or UPF in the case of the SMF, SGW in the case of the MME).

[0103] In the process of processing the session establishment request, the core network 102 can select a gateway (GW) 300 for data transmission (UPF for 5G, S / P-GW for 4G).

[0104] In operation 312, the core network 102 (e.g., NF (SMF for 5G, MME for 4G)) supporting session management regarding the user equipment may establish a ProSe session association with the ProSe function 103. The ProSe session association may refer to an association between the core network 102 (SMF or MME) and the ProSe function 103 to manage the session of the UE 100 for ProSe communication (e.g., continuously send or receive session related information). In a ProSe session association message sent or received between the core network 102 and the ProSe function 103 to establish the ProSe session association, a session ID (PDU session ID for 5G, PDN connection ID for 4G), a user equipment ID (e.g., IMSI, GPSI, SUPI, 5G-GUTI, etc.) may be included. Based on the information included in the ProSe session association message, the ProSe function 103 may know that the service that the UE 100 is using via direct communication will be used for network communication.

[0105] In operation 314a or operation 314b, the UE 100 or the core network 102 that has completed the session establishment process may send a data path switching notification message to the ProSe function 103. The data path switching notification message may include information indicating the ProSe session association of operation 312. For example, the information indicating the ProSe session association may include a session ID, a user equipment ID, etc. Based on the information indicating the ProSe session association, the ProSe function 103 may know that the service being used by the UE 100 via direct communication has been switched to network communication, and may update the ProSe session context in operation 316. The ProSe session context may include information related to the ProSe session of the UE 100.

[0106] After completing the session establishment, in operation 318, the UE 100 may transmit uplink data to the DN 301. The uplink data may be data transmitted by the UE 100 to the DN 301 or another UE 200. In operation 320, the DN 301 may process the transmission of the data received from the UE 100 in operation 318. Figure 4 The data transmission flow of operation 320 is described in detail. In operation 322, when there is data to be transmitted to UE 100, DN 301 may transmit downlink data. The downlink data may be data transmitted to UE 100 by DN 301 or another UE 200.

[0107] When the service being used corresponds to ProSe SSC mode 2 (break before make), the UE 100 switching the data path according to the embodiment of the present disclosure may start Figure 3 The direct communication is terminated before the session establishment procedure described in operation 310, during the session establishment procedure, or after the session establishment procedure is completed and before the uplink data is sent in operation 318.

[0108] Alternatively, when the service being used corresponds to ProSe SSC mode 3 (make before break), the UE 100 may complete Figure 3 The session establishment procedure described in , and the direct communication is terminated after the uplink data is sent in operation 318.

[0109] Figure 4 is a sequence diagram illustrating a process for switching a data path according to an embodiment of the present disclosure. In detail, Figure 4 A process for switching a direct communication path to a network communication path is shown.

[0110] Reference Figure 4In operation 410, DN 301 may process transmission of downlink data sent to UE 200. Downlink data may be data sent by DN 301 to UE 200, or data received during Figure 3 In operation 320 of FIG. 3 , the DN 301 receives data from the UE 100 and transmits the data to the UE 200 .

[0111] In operation 412, the DN 301 may transmit downlink data (UPF for 5G, S / P-GW for 4G) to the GW 400. When there is no base station information for transmitting the downlink data received from the DN 301 in the GW 400, in operation 414, the GW 400 may transmit a downlink data notification (DDN) to the core network 202. In operation 416, the core network 202 (e.g., an NF supporting mobility management on the user equipment (AMF for 5G, MME for 4G)) may transmit a paging message to the UE 200. Upon receiving the paging message, in operation 418, the UE 200 may perform a service request procedure.

[0112] In operation 420, the core network 202 (e.g., a NF supporting session management for user equipment (SMF for 5G, MME for 4G)) may establish a ProSe session association with the ProSe function 203. A ProSe session association message sent or received between the core network 202 and the ProSe function 203 may include a session ID (PDU session ID for 5G, PDN connection ID for 4G), a user equipment ID (e.g., IMSI, GPSI, SUPI, 5G-GUTI, etc.). Based on the information included in the ProSe session association message, the ProSe function 203 may know that the service that the UE 200 is using via direct communication will be used by network communication.

[0113] In operation 422a or operation 422b, the UE 200 or the core network 202 that has completed the session modification procedure may send a data path switching notification message to the ProSe function 203. The data path switching notification message may include information indicating the ProSe session association of operation 420. For example, the information indicating the ProSe session association may include a session ID, a user equipment ID, etc. Based on the information indicating the ProSe session association, the ProSe function 203 may know that the service being used by the UE 200 via direct communication is switched to network communication, and may update the ProSe session context in operation 424.

[0114] In operation 426 , the GW 400 may transmit the downlink data received from the DN 301 to the UE 200 .

[0115] When the service being used corresponds to ProSe SSC mode 2 (break before make), the UE 200 switching the data path according to the embodiment of the present disclosure may start Figure 4 The direct communication is terminated before or during the session switching process described in .

[0116] Optionally, when the service being used corresponds to ProSe SSC mode 3 (make before break), the UE 100 may complete Figure 4 The session switching process described in , and the direct communication is terminated after sending the downlink data in operation 426.

[0117] Figure 5 is a sequence diagram illustrating a process for switching a data path according to an embodiment of the present disclosure. In detail, Figure 5 A process for switching a network communication path to a direct data communication path is shown.

[0118] Reference Figure 5 According to an embodiment of the present disclosure, the UE 100 or 200 that has switched the network communication path to the direct communication path may send a data path switching notification message to the ProSe function 103 or 203 in operation 510. The data path switching notification message may include a session ID (PDU session ID for 5G, PDN connection ID for 4G), a user equipment ID (e.g., IMSI, GPSI, SUPI, 5G-GUTI, etc.). In operation 512, based on the information included in the data path switching notification message, the ProSe function 103 or 203 may know that the service that the UE 100 or 200 is using via the network communication is scheduled to be switched or has been switched to the direct communication.

[0119] In operation 514, the ProSe function 103 or 203 may send a ProSe session association update request message to the core network 102 or 202NF (e.g., SMF or MME) that manages the session to be switched. The ProSe session association update request message may include information indicating that the data path of the UE 100 or 200 is to be switched or has been switched to direct communication (e.g., information about the session to be switched). For example, in the ProSe session association update request message, a session ID (PDU session ID for 5G, PDN connection ID for 4G) and a user equipment ID (e.g., IMSI, GPSI, SUPI, 5G-GUTI, etc.) of the session to be switched may be included. The core network 102 or 202NF may know, based on the information included in the ProSe session association update request message, that the service that the UE 100 or 200 is using via network communication is scheduled to be switched or has been switched to direct communication.

[0120] In operation 516, the core network 102 or 202NF may continue to activate or deactivate the PDU session related to the data path exchange. For example, when the UE 100 or 200 switches the service being used via network communication to direct communication, the core network 102 or 202NF may deactivate the PDU session activated for network communication.

[0121] In operation 518, the core network 102 or 202NF may reply the ProSe function 103 or 203 with a ProSe session association update response message. In operation 520, the ProSe function 103 or 203 may update the ProSe session context related to the ProSe session of the UE 100 or 200 based on the ProSe session association update response message.

[0122] Figure 6 is a sequence diagram illustrating a process for switching a data path according to an embodiment of the present disclosure. In detail, Figure 6 A process for switching a network communication path to a direct data communication path is shown.

[0123] Reference Figure 6 In operation 610, the base station (RAN) 101 or 201 according to an embodiment of the present disclosure may send a session status notification message of a session being used by the user equipment to the core network 102 or 202NF (e.g., AMF, SMF, or MME). The session status notification message may include a session ID (PDU session ID for 5G, PDN connection ID for 4G) and a user equipment ID (e.g., IMSI, GPSI, SUPI, 5G-GUTI, etc.). In operation 612, the core network 102 or 202NF may know, based on the information included in the session status notification message, that the service being used by the user equipment via network communication is scheduled to be switched or has been switched to direct communication.

[0124] In operation 614, the core network 102 or 202NF may send a ProSe session association update request message to the ProSe function that manages the session to be switched. The ProSe session association update request message may include information indicating that the data path of the UE 100 or 200 will be switched or has been switched to direct communication (e.g., information about the session to be switched). For example, in the ProSe session association update request message, a session ID (PDU session ID for 5G, PDN connection ID for 4G) and a user equipment ID (e.g., IMSI, GPSI, SUPI, 5G-GUTI, etc.) of the session to be switched may be included. In operation 616, based on the information included in the ProSe session association update request message, the ProSe function may know that the service that the user equipment is using via network communication will be switched or has been switched to direct communication, and may update the ProSe session context related to the ProSe session of the UE 100 or 200 based on the ProSe session association update request message.

[0125] In operation 618 , the ProSe function 103 or 203 may reply to the core network 102 or 202NF with a ProSe session association update response message.

[0126] In operation 620, the core network 102 or 202NF may continue to activate or deactivate the PDU session related to the data path switching. For example, when the user equipment switches the service being used via network communication to direct communication, the core network 102 or 202NF may deactivate the PDU session activated for network communication.

[0127] Figure 7 is a block diagram showing a detailed structure of a user equipment according to an embodiment of the present disclosure. Figure 7 The user equipment may refer to Figure 2 UE 100 or 200.

[0128] like Figure 7 As shown, the user equipment of the present disclosure may include a processor 730, a transceiver 710, and a memory 720. However, the components of the user equipment are not limited to the above examples. For example, the user equipment may include more or fewer components than the above components. In addition, the processor 730, the transceiver 710, and the memory 720 may be implemented in the form of a single chip.

[0129] According to an embodiment, the processor 730 may control a series of processes in which the user equipment may operate according to the above-mentioned embodiments of the present disclosure. For example, the processor 730 may control the components of the user equipment to perform the direct communication session management method according to the embodiment of the present disclosure. A plurality of processors 730 may be included, and the processor 730 may perform operations for protecting the above-mentioned information of the present disclosure by running a program stored in the memory 720.

[0130] The transceiver 710 may send a signal to a base station or receive a signal from a base station. The signal sent to or received from the base station may include control information and data. The transceiver 710 may include an RF transmitter for up-converting and amplifying the frequency of the transmitted signal, and an RF receiver for performing low noise amplification on the received signal and down-converting the received signal. However, the transceiver 710 is only an example, and the components of the transceiver 710 are not limited to the RF transmitter and the RF receiver. In addition, the transceiver 710 may receive a signal via a wireless channel and output it to the processor 730, and send a signal output from the processor 730 via a wireless channel.

[0131] According to an embodiment, the memory 720 may store programs and data required for the operation of the user equipment. In addition, the memory 720 may store control information or data included in a signal sent or received by the user equipment. The memory 720 may be configured in a storage medium such as a ROM, RAM, hard disk, CD-ROM or DVD or a combination thereof. In addition, a plurality of memories 720 may be included. According to an embodiment, the memory 720 may store a program for establishing group communication by using D2D communication, which is an embodiment of the present disclosure described above.

[0132] Figure 8 is a block diagram showing a detailed structure of a base station according to an embodiment of the present disclosure. Figure 8 The base station may include Figures 1 to 6 RAN 101 or 201.

[0133] like Figure 8 As shown, the base station of the present disclosure may include a processor 830, a transceiver 810, and a memory 820. However, the components of the base station are not limited to the above examples. For example, the base station may include more or fewer components than the above components. In addition, the processor 830, the transceiver 810, and the memory 820 may be implemented in the form of a single chip.

[0134] The processor 830 may control a series of operations so that the base station can operate according to the above-mentioned embodiments of the present disclosure. For example, the processor 830 may control the components of the base station to execute the direct communication session management method according to the embodiments of the present disclosure.

[0135] The transceiver 810 may send a signal to or receive a signal from a user equipment. The signal sent to or from the user equipment may include control information and data. The transceiver 810 may include an RF transmitter for up-converting and amplifying the frequency of the transmitted signal, and an RF receiver for low-noise amplification and down-conversion of the received signal. However, the transceiver 810 is only an example, and the components of the transceiver 810 are not limited to the RF transmitter and the RF receiver. In addition, the transceiver 810 may receive a signal via a wireless channel and output it to the processor 830, and send a signal output from the processor 830 via a wireless channel. There may be multiple processors 830, and the processor 830 may perform operations for protecting the information of the present disclosure described above by running a program stored in the memory 820.

[0136] According to an embodiment, the memory 820 may store programs and data required for the operation of the base station. In addition, the memory 820 may store control information or data included in a signal sent or received by the base station. The memory 820 may be configured in a storage medium such as a ROM, RAM, hard disk, CD-ROM or DVD or a combination thereof. In addition, a plurality of memories 820 may be included. According to an embodiment, the memory 820 may store a program for running the direct communication session management method of the embodiment of the present disclosure described above.

[0137] Fig. 9 is a block diagram showing the structure of a core network object according to an embodiment of the present disclosure. The terms "unit" and "device" used herein refer to a unit for processing at least one function or operation, and may be implemented by hardware or software or a combination of hardware and software. For example, a core network object may include a ProSe function.

[0138] Reference Fig. 9 , the core network object can be configured by including a transceiver 910, a memory 920 and a processor 930.

[0139] The transceiver 910 may provide an interface for performing communication with other devices in the network. That is, the transceiver 910 may convert a bit string sent from a core network object to another device into a physical signal, and convert a physical signal received from another device into a physical signal. That is, the transceiver 910 may send and receive signals. Therefore, the transceiver 910 may be referred to as a modem, a transmitter, a receiver, a communication unit, or a communication module. Here, the transceiver 910 enables the core network object to communicate with other devices or systems via a backhaul connection (e.g., a wired backhaul or a wireless backhaul) or other connection methods or via a network.

[0140] The memory 920 may store data such as basic programs, application programs, and setting information for the operation of core network objects. The memory 920 may be configured with a volatile memory, a non-volatile memory, or a combination of a volatile memory and a non-volatile memory. Specifically, the memory 920 may provide stored data according to a request from the processor 930.

[0141] The processor 930 may control the overall operation of the core network object. For example, the processor 930 may send or receive a signal through the transceiver 910. In addition, the processor 930 may write data to the memory 920 and read data from the memory 920. To this end, the processor 930 may include at least one processor. The processor 930 may control the core network object to perform operations according to the above-mentioned various embodiments. For example, the processor 930 may control the components of the core network object to perform the direct communication session management method according to the embodiment of the present disclosure.

[0142] The methods according to the embodiments described in the claims or the specification of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

[0143] When implemented as software, a computer-readable storage medium or a computer program product storing one or more programs (e.g., software modules) may be provided. One or more programs or computer program products stored in a computer-readable storage medium are configured to be run by one or more processors in an electronic device. One or more programs include instructions for directing an electronic device to run a method according to an embodiment of the present disclosure as described in the claims or specification of the present disclosure.

[0144] The program (e.g., software module or software) may be stored in random access memory (RAM), nonvolatile memory including flash memory, read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), magnetic disk storage device, compact disk-ROM (CD-ROM), digital versatile disk (DVD), another type of optical storage device, or magnetic tape cassette. Alternatively, the program may be stored in a memory that includes a combination of some or all of the above memories. Furthermore, each component memory may include a plurality.

[0145] The program may also be stored in an attachable storage device accessible via a communication network such as the Internet, an intranet, a local area network (LAN), a wide area network (WLAN), or a storage area network (SAN), or a combination thereof. The storage device may be connected to the device executing the embodiments of the present disclosure via an external port. Another storage device on the communication network may also be connected to the device executing the embodiments of the present disclosure.

[0146] In the above-mentioned embodiment of the present disclosure, the components included in the present disclosure are expressed in the singular or plural form according to the embodiment of the present disclosure. However, for the convenience of explanation, the singular or plural form is appropriately selected, and the present disclosure is not limited thereto. In this way, the components expressed in the plural form may also be configured as a single component, and the components expressed in the singular form may also be configured as multiple components.

[0147] The embodiments disclosed in this specification and the accompanying drawings are presented only as specific examples to better explain the present disclosure and help understand the present disclosure, and are not intended to limit the scope of the present disclosure. That is, it is obvious to a person skilled in the art in the field to which the present disclosure belongs that other modifications can be made based on the present disclosure. In addition, these embodiments can be combined with each other as needed. For example, one embodiment of the present disclosure and part of another embodiment can be combined with each other. In addition, the embodiments can be implemented in other systems, such as LTE systems, 5G or NR systems, and other modifications can also be made based on the above-mentioned embodiments.

Claims

1. A method performed by a user equipment UE in a wireless communication system, the method comprising: receiving information about a communication path from a network entity, wherein the information about the communication path indicates a path through a Uu interface or a path through a PC5 interface; selecting, based on the information about the communication path, a communication path for the proximity service (ProSe) service as a path through the Uu interface or a path through the PC5 interface; and performing communication with another UE via the selected communication path; Therein, in a case where the information about the communication path indicates a path through the PC5 interface and the UE and the other UE are not adjacent to each other, the communication path for the ProSe service is selected as a path through the Uu interface.

2. The method according to claim 1, wherein: The information about the communication path is determined by the network entity based on service information provided by the ProSe application server, the service information including information about the path selected by the ProSe application server.

3. The method according to claim 1, wherein: The network entity is a Policy Control Function PCF. The method of claim 1 , further comprising performing a registration process with a network.

5. A user equipment UE in a wireless communication system, the UE comprising: Transceiver; as well as A processor coupled to the transceiver and configured to: receiving information about a communication path from a network entity, wherein the information about the communication path indicates a path through a Uu interface or a path through a PC5 interface; selecting, based on the information about the communication path, a communication path for the proximity service (ProSe) service as a path through the Uu interface or a path through the PC5 interface; and performing communication with another UE via the selected communication path; Therein, in a case where the information about the communication path indicates a path through the PC5 interface and the UE and the other UE are not adjacent to each other, the communication path for the ProSe service is selected as a path through the Uu interface.

6. The UE according to claim 5, wherein: The information about the communication path is determined by the network entity based on service information provided by the ProSe application server, the service information including information about the path selected by the ProSe application server.

7. The UE according to claim 5, wherein: The network entity is a Policy Control Function PCF.

8. The UE according to claim 5, wherein: The processor is also configured to perform a registration process with the network.

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