Apparatus and method for supporting one-to-one communication service in a wireless communication system

Abstract

A method for performing unicast communication executed by a first user equipment (UE), comprising: sending a direct communication request message, generating a profile of a PC5 unicast link, receiving a response message from a second UE based on a result of establishing the PC5 unicast link; and sending a data message to the second UE via the PC5 unicast link based on the response message, wherein the profile includes at least one of: a layer-2 identifier (ID) of the first UE, an application layer ID of the first UE, a layer-2 ID of the second UE, an application layer ID of the second UE, a PC5 fifth generation (5G) quality of service (QoS) indicator (PQI), or a PC5 QoS flow identifier (PFI) associated with the PQI).

Description

Technical Field

[0001] The present disclosure relates to a method and apparatus for supporting one-to-one communication services in a wireless communication system. Technical Background

[0002] In order to meet the increasing demand for wireless data traffic after the commercialization of the fourth-generation (4G) communication system, efforts to develop an enhanced fifth-generation (5G) communication system or a pre-5G communication system are still ongoing. For this purpose, the 5G communication system or the pre-5G communication system is referred to as a super 4G network communication system or a post-long term evolution (LTE) system.

[0003] In order to achieve high data transmission rates, implementing a 5G communication system in the extremely high frequency (mmWave) band (e.g., 60 GHz band) is being considered. In order to reduce the path loss of radio waves and increase the transmission distance of radio waves in the extremely high frequency band, in the 5G communication system, technologies for beamforming, massive multiple-input multiple-output (MIMO), full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and massive antennas are being discussed.

[0004] In addition, in order to improve the network of the system, various technologies have been developed for the 5G communication system, such as evolved small cells, advanced small cells, cloud radio access network (cloud RAN), ultra-dense network, device-to-device communication (D2D), wireless backhaul, mobile network, cooperative communication, coordinated multi-point (CoMP), and interference cancellation. In addition, other technologies have been developed for the 5G communication system, such as hybrid frequency shift keying (FSK) and quadrature amplitude modulation (QAM) modulation (FQAM) and sliding window superposition coding (SWSC) based on advanced coding modulation (ACM), and non-orthogonal multiple access (NOMA) and sparse code multiple access (SCMA) based on filter bank multi-carrier (FBMC).

[0005] Meanwhile, the Internet is evolving from a human-centered network in which people generate and consume information to an Internet of Things (IoT) network in which distributed components such as objects send, receive, and process information. The Internet of Everything (IoE) technology, which combines IoT technology with big data processing technology, etc., through connections to cloud servers, etc., is emerging. Implementing the IoT requires various technical factors, such as sensing technology, wired / wireless communication, network infrastructure, service interface technology, and security technology. Recently, technologies including sensor networks, machine-to-machine (M2M), and machine type communication (MTC) for connections between objects have been studied.

[0006] In the IoT environment, intelligent Internet technology (IT) services are provided to collect and analyze data generated by connected objects, creating new value for human life. IoT can be applied to various fields such as smart homes, smart buildings, smart cities, smart cars / connected cars, smart grids, healthcare, smart appliances, and advanced medical services through the integration and combination of existing information technology (IT) with various industries.

[0007] Therefore, various attempts are being made to apply 5G communication systems to IoT networks. For example, technologies such as sensor networks, M2M, and MTC are realized through technologies such as beamforming, MIMO, and array antennas, which are 5G communication technologies. Applying cloud radio access network (CRAN) as a big data processing technology is also an example of the integration of 5G technology and IoT technology.

[0008] Vehicle to Everything (V2X) is a general term representing all forms of communication methods applicable to vehicles on the road, and V2X is combined with the development of wireless communication technology to achieve various additional services as well as initial safety use cases.

[0009] As a technology for providing V2X services, the Wireless Access in Vehicular Environments (WAVE) standard based on IEEE 802.11p and IEEE P1609 has been standardized. However, WAVE is a Dedicated Short Range Communication (DSRC) technology, which has the limitation that the message transmission distance between vehicles is restricted.

[0010] To overcome such limitations, the 3rd Generation Partnership Project (3GPP) is standardizing cellular-based V2X technology. In Release 14 / Release 15, the Evolved Packet System (EPS) V2X standard based on the LTE system has been completed, and in Release 16, the standardization of 5th Generation System (5GS) V2X based on the New Radio (NR) system is underway. Summary of the Invention

[0011] Solution to the Problem

[0012] According to some embodiments of the present disclosure, a method of operating a first user equipment includes: obtaining first information for establishing a communication link with a second user equipment, transmitting second information from an application layer to a Service Enabling (SE) layer based on the first information; configuring a layer-2 ID of the first user equipment as a source layer-2 ID of a direct communication request message through the SE layer; when it is determined to perform a communication link establishment process based on the second information, sending a direct communication request message to the second user equipment; and receiving a direct communication response message from the second user equipment based on the direct communication request message.

[0013] According to various embodiments of the present disclosure, a method of operating a second user equipment includes: receiving a direct communication request message from a first user equipment, checking a destination address of the direct communication request message to determine whether to perform a communication link establishment with the first user equipment by a Service Enabling (SE) layer, and when it is determined to perform the communication link establishment, sending a direct communication response message to the first user equipment.

[0014] Additional aspects will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the presented embodiments of the disclosure.

[0015] According to certain embodiments of the present disclosure, a method of performing unicast communication by a first user equipment (UE) includes: sending a direct communication request message, generating a profile of a PC5 unicast link, receiving a response message from a second UE based on a result of establishing the PC5 unicast link; and sending a data message to the second UE through the PC5 unicast link based on the response message, wherein the profile includes at least one of: a layer-2 identifier (ID) of the first UE, an application layer ID of the first UE, a layer-2 ID of the second UE, an application layer ID of the second UE, a PC5 fifth generation (5G) Quality of Service (QoS) Indicator (PC5 5 th generation QoSIndicator, PQI) or a PC5 QoS Flow identifier (PC5 QoS Flow identifier, PFI) associated with the PQI.

[0016] According to various embodiments, the layer-2 ID of the second UE and the layer-2 ID of the first UE can be used to establish initial signaling of the PC5 unicast link, and the destination layer-2 ID of the direct communication request message can be the layer-2 ID of the second UE.

[0017] The destination layer-2 ID can be equal to or different for vehicle-to-everything (V2X) service types.

[0018] A PFI may be allocated in the V2X layer of the first UE, and the V2X layer of the first UE may provide at least one of a data message, a PFI, or a PQI to the access (Access Stratum, AS) layer of the first UE.

[0019] In some embodiments, the method may further include indicating to the AS layer from the V2X layer whether a direct communication request message or a response message is for signaling.

[0020] The method may further include changing at least one of the layer-2 ID of the first UE, the layer-2 ID of the second UE, the application layer ID of the first UE, or the application layer ID of the second UE.

[0021] The method may further include updating a profile based on an update of a link layer identifier or a result of a change in at least one of the layer-2 ID of the first UE, the layer-2 ID of the second UE, the application layer ID of the first UE, or the application layer ID of the second UE.

[0022] In various embodiments according to the present disclosure, a direct communication request message may include first information about at least one of a PQI or a PFI, and a response message may include second information about at least one of a PQI or a PFI.

[0023] According to some embodiments of the present disclosure, a first UE for performing unicast communication includes: a transceiver; and at least one processor coupled to the transceiver and configured to: send a direct communication request message based on a profile; determine a profile of a PC5 unicast link; receive a response message from a second UE based on a result of establishment of the PC5 unicast link; and send a data message to the second UE via the PC5 unicast link based on the response message, wherein the profile includes at least one of a layer-2 identifier (ID) of the first UE, an application layer ID of the first UE, a layer-2 ID of the second UE, an application layer ID of the second UE, a PC5 fifth generation (5G) quality of service (QoS) indicator (PQI), or a PC5 QoS flow identifier (PFI) associated with the PQI.

[0024] In some embodiments, the layer-2 ID of the second UE and the layer-2 ID of the first UE may be used for initial signaling of establishing a PC5 unicast link, and a destination layer-2 ID of the direct communication request message may be the layer-2 ID of the second UE.

[0025] The destination layer-2 ID may be equal or different for vehicle-to-everything (V2X) service types.

[0026] A PFI may be allocated in the V2X layer of the first UE, and the V2X layer of the first UE may provide at least one of a data message, a PFI, or a PQI to the access (AS) layer of the first UE.

[0027] The at least one processor may also be configured to indicate to the AS layer from the V2X layer whether a direct communication request message or a response message is for signaling.

[0028] The at least one processor may also be configured to change at least one of the layer-2 ID of the first UE, the layer-2 ID of the second UE, the application layer ID of the first UE, or the application layer ID of the second UE.

[0029] According to some embodiments, the at least one processor may also be configured to update a profile based on the result of an update of a link layer identifier or a change in at least one of the layer-2 ID, the application layer ID of the first UE, or the application layer ID of the second UE.

[0030] The direct communication request message may include first information regarding at least one of the PQI or the PFI, and the response message may include second information regarding at least one of the PQI or the PFI.

[0031] Before proceeding with the following detailed description, it may be advantageous to set forth the definitions of certain words and phrases used throughout this patent document: The terms "include" and "comprise," and derivatives thereof, mean inclusion without limitation; the term "or" is inclusive and means and / or; the phrases "associated with" and "associated therewith," and derivatives thereof, may mean include, be included within, interconnect with, contain, be contained within, be connected to or connected with, coupled to or coupled with, communicate with, cooperate with, interleave, juxtapose, be proximate to, be bound to or bound with, have, have the attribute of, etc.; and the term "controller" means any device, system, or part thereof that controls at least one operation, such a device may be implemented in hardware, firmware, software, or some combination of at least two thereof. It should be noted that the functions associated with any particular controller may be centralized or distributed, whether local or remote.

[0032] In addition, the various functions described below can be implemented or supported by one or more computer programs, each of which is formed of computer-readable program code and contained in a computer-readable medium. The terms "application" and "program" refer to one or more computer programs, software components, instruction sets, procedures, functions, objects, classes, instances, related data, or portions thereof suitable for implementation in appropriate computer-readable program code. The phrase "computer-readable program code" includes any type of computer code, including source code, object code, and executable code. The phrase "computer-readable medium" includes any type of medium that can be accessed by a computer, such as read-only memory (ROM), random access memory (RAM), hard disk drives, optical discs (CDs), digital versatile discs (DVDs), or any other type of memory. A "non-transitory" computer-readable medium excludes wired, wireless, optical, or other communication links that transmit transitory electrical signals or other signals. Non-transitory computer-readable media include media that can permanently store data and media that can store data and later overwrite it, such as rewritable optical discs or erasable memory devices.

[0033] Throughout this patent document, definitions of particular words and phrases are provided. Those of ordinary skill in the art should understand that, in many if not most instances, such definitions apply to the prior as well as future use of such defined words and phrases. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] From the following description taken in conjunction with the drawings, the above and other aspects, features, and advantages of certain embodiments of the present disclosure will become more apparent, in which:

[0035] Figure 1 An example of the configuration of a vehicle communication system according to certain embodiments of the present disclosure is shown;

[0036] Figure 2a An example of the control plane protocol stack of a user equipment according to certain embodiments of the present disclosure is shown;

[0037] Figure 2b An example of the user plane protocol stack of a user equipment according to certain embodiments of the present disclosure is shown;

[0038] Figure 3 An example of a direct communication link establishment process according to certain embodiments of the present disclosure is shown;

[0039] Figure 4 An example of a process for changing a user equipment identifier according to certain embodiments of the present disclosure is shown;

[0040] Figure 5 An example of a process for releasing a direct communication link according to certain embodiments of the present disclosure is shown;

[0041] Figure 6 illustrates an example of a process for releasing a direct communication link according to another embodiment of the present disclosure;

[0042] Figure 7 illustrates an example of a data transmission process using a direct communication link according to certain embodiments of the present disclosure;

[0043] Figure 8a illustrates an example of a process performed by a user equipment to obtain service information from a network during an initial registration process according to certain embodiments of the present disclosure;

[0044] Figure 8b illustrates an example of a process performed by a user equipment to obtain service information from a network in response to a request from the network according to certain embodiments of the present disclosure;

[0045] Figure 8c illustrates an example of a process performed by a user equipment to obtain service information from a network in response to a request from the user equipment according to certain embodiments of the present disclosure;

[0046] Figure 9a illustrates an example of the configuration of a network entity according to certain embodiments of the present disclosure in block diagram form; and

[0047] Figure 9b illustrates an example of the configuration of a user equipment according to certain embodiments of the present disclosure in block diagram form. Detailed Description

[0048] The following discussion Figures 1 to 9b and the various embodiments used herein to describe the principles of the present disclosure are merely exemplary and should not be construed in any way as limiting the scope of the present disclosure. Those skilled in the art will understand that the principles of the present disclosure can be implemented in any suitably arranged system or device.

[0049] Hereinafter, the operating principles of the present disclosure will be described in detail with reference to the accompanying drawings. However, when a detailed description of known functions or configurations associated with the present disclosure is determined to unnecessarily obscure the gist of the present disclosure, the detailed description will be omitted. Although the following terms are defined in consideration of the functions of the present disclosure, they may vary according to the intention of the user or operator, judicial precedent, etc. Therefore, the terms must be defined based on the content of the entire specification.

[0050] For the same reason, some components shown in the drawings may be enlarged or shown schematically, or some components may be omitted. In addition, the dimensions of the components may not reflect the actual dimensions. In the drawings, the same or corresponding components are given the same reference numerals.

[0051] Throughout the disclosure, the expression "at least one of a, b, or c" means: only a; only b; only c; a and b, a and c, b and c; all of a, b, and c or variants thereof.

[0052] Examples of terminals may include user equipment (UE), mobile station, mobile phone (MS), smart phone, computer, or multimedia system capable of performing communication functions.

[0053] As used in this disclosure, the term controller includes a processor. Throughout the specification, a layer (or layer device) may also be referred to as an entity.

[0054] Advantages and features of the present disclosure and methods of achieving them will become apparent with reference to the drawings showing embodiments. Embodiments in accordance with the present disclosure may take many different forms, and the scope of the present disclosure should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided to make the present disclosure thorough and complete, and to fully convey the concepts of the present disclosure to those of ordinary skill in the art, and the present disclosure is defined only by the scope of the claims. Throughout the specification, like reference numerals denote like elements.

[0055] It should be understood that the combination of blocks in the process flow diagrams and the flowchart illustrations can be performed by computer program instructions. These computer program instructions can be loaded into a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, such that the instructions executed by the processor of the computer or other programmable data processing device create means for performing the functions described in the (multiple) flowchart blocks. These computer program instructions can also be stored in a computer-usable or computer-readable memory, which can direct a computer or other programmable data processing device to implement functions in a particular manner, such that the instructions stored in the computer-usable or computer-readable memory can also produce a manufacture item that includes instruction means for performing the functions described in the (multiple) flowchart blocks. The computer program instructions can also be installed on a computer or other programmable data processing device, so that a series of operation steps can be performed on the computer or other programmable data processing device to create a computer-executable process. Therefore, the instructions for operating a computer or other programmable data processing device can also provide steps for performing the functions described in the (multiple) flowchart blocks.

[0056] In addition, each block may represent a module, a code segment, or a portion of code that includes one or more executable instructions for performing the (multiple) specified logical functions. It should also be noted that in some alternative implementations, the functions recited in the blocks may occur out of order. For example, two blocks shown in succession may in fact be executed substantially concurrently, or these blocks may sometimes be executed in the reverse order depending on the corresponding functions.

[0057] As used herein, the terms "portion", "module", or "unit" refer to a unit capable of performing at least one function or operation, and can be implemented as a software or hardware component, such as a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC). However, the terms "portion", "module", or "unit" are not limited to software or hardware. A "portion", "module", or "unit" can be configured in an addressable storage medium, or can be configured to run on at least one processor. Thus, by way of example, a "portion", "module", or "unit" includes: components such as software components, object-oriented software components, class components, and task components; processors; functions; attributes; procedures; subroutines; program code segments; drivers; firmware; microcode; circuits; data; databases; data structures; tables; arrays, and variables. The functions provided in components and "portions", "modules", or "units" can be combined into a smaller number of components and "portions", "modules", and "units", or subdivided into additional components and "portions", "modules", or "units". In addition, components and "portions", "modules", or "units" can be configured to run on one or more central processing units (CPUs) in a device or a secure multimedia card. In addition, in an embodiment, a "portion", "module", or "unit" can include one or more processors.

[0058] As used herein, terms indicating connection nodes, terms indicating network entities, terms indicating messages, terms indicating interfaces between network entities, terms indicating various identification information, etc. are examples for convenience of description. Thus, the present disclosure is not limited to these terms, and other terms having equivalent technical meanings can be used.

[0059] Hereinafter, for convenience of description, terms and names defined in the standards of the fifth generation (5G), new radio (NR), and long term evolution (LTE) systems are used in the present disclosure. However, the present disclosure is not limited by the terms and names, and can be applied to systems based on other standards in the same manner.

[0060] The detailed description of embodiments of the present disclosure can be provided with reference to the terms and concepts set forth in one or more communication standards defined by the Third Generation Partnership Project (3GPP). However, as informed by the technical knowledge of those of ordinary skill in the art to which the present disclosure pertains, embodiments according to the present disclosure can be practiced in other communication systems having a similar technical background with minor modifications consistent with the present disclosure.

[0061] In some cases, the detailed description of embodiments of the present disclosure is described with reference to vehicle communication services. However, embodiments according to the present disclosure are not limited to the selection of explanatory examples herein, and the present disclosure can be applied to other services provided over a 5G network.

[0062] The 5G system supports various services of the 4G system. For example, representative services include enhanced mobile broadband (eMBB), ultra-reliable and low-latency communication (URLLC), massive machine type communication (mMTC), and evolved multimedia broadcast / multicast service (eMBMS). A system that provides URLLC service is called a URLLC system, and a system that provides eMBB service is called an eMBB system. In addition, the terms "service" and "system" can be used interchangeably.

[0063] The URLLC service was not considered in the 4G system but is newly considered in the 5G system. Compared with other services, the URLLC service requires conditions of ultra-high reliability (e.g., a packet error rate of about 10 -5 ) and low latency (e.g., about 0.5 milliseconds). To meet such strict requirements, the URLLC service may need to apply a shorter transmission time interval (TTI) than the eMBB service, and various operation methods for using the URLLC service are considered.

[0064] Meanwhile, the Internet is evolving from a human-centered network where people generate and consume information to an Internet of Things (IoT) network where distributed components such as object information send, receive, and process information. The Internet of Everything (IoE) technology, which combines IoT technology with big data processing technology, etc. through connections to cloud servers, etc., is emerging. Implementing the IoT requires various technical factors, such as sensing technology, wired / wireless communication, network infrastructure, service interface technology, and security technology. Recently, technologies including sensor networks, machine-to-machine (M2M), and machine type communication (MTC) for connections between objects are being studied.

[0065] Figure 1 An example of the configuration of a vehicle communication system according to certain embodiments of the present disclosure is shown.

[0066] Reference Figure 1As a non - limiting example, a user equipment (UE) (which, according to the present disclosure, includes but is not limited to a user terminal, a terminal, or a vehicle user equipment) 110 can communicate with another user equipment 120 through a mobile communication system 130 using direct communication (e.g., device - to - device (D2D), ProSe, PC5, and sidelink communication) 140 or network communication 150 and 160. In direct communication 140, the message transmission / reception between the user equipment 110 and the other user equipment 120 can be performed through a PC5 link. In network communication 150 and 160, a message to be sent from a sending vehicle user equipment to a receiving vehicle user equipment can be sent to the network through a Uu link and then sent to the receiving vehicle user equipment through the Uu link. The mobile communication system 130 can be an evolved packet core (EPC) system defined in 3GPP or a fifth - generation core (5GC) system, or another communication system different from 3GPP. The direct communication 140 can be provided by using long - term evolution radio access technology (LTE RAT), NR RAT, or non - 3GPP RAT (such as Wi - Fi).

[0067] Figure 2a FIG. shows an example of a control - plane protocol stack of a user equipment according to certain embodiments of the present disclosure. Figure 2b FIG. shows an example user - plane protocol stack of a user equipment according to certain embodiments of the present disclosure. Refer to Figure 2a As a non - limiting example, the user equipment 110 can be a sending user equipment, and the user equipment 120 can be a receiving user equipment. However, for the sake of description, the sending user equipment and the receiving user equipment will be referred to as the user equipment 110 and the user equipment 120, respectively.

[0068] Refer to Figure 2a As an illustrative example, the control - plane protocol stacks of the user equipments 110 and 120 can be composed of PC5 signaling protocol layers 210 and 215, RRC layers 220 and 225, PDCP layers 230 and 235, RLC layers 240 and 245, MAC layers 250 and 255, and PHY layers 260 and 265. The RRC layers 220 and 225, PDCP layers 230 and 235, RLC layers 240 and 245, and MAC layers 250 and 255 are collectively referred to as the access stratum.

[0069] The PC5 signaling protocol layers 210 and 215 can provide functions for link establishment and link maintenance for the direct communication 140 between the user equipment 110 and the user equipment 120.

[0070] Refer to Figure 2bAs a non - limiting example, the user - plane protocol stacks of user equipments 110 and 120 can be composed of application layers 270 and 275, service enabling (SE) layers 280 and 285, SDAP layers 290 and 295, PDCP layers 230 and 235, RLC layers 240 and 245, MAC layers 250 and 255, and PHY layers 260 and 265. The SDAP layers 290 and 295, PDCP layers 230 and 235, RLC layers 240 and 245, and MAC layers 250 and 255 are collectively referred to as the access stratum (AS).

[0071] In some embodiments, the SE layers 280 and 285 can be intermediate layers for performing operations of the application layers 270 and 275, and provide functions dedicated to each application or service. The SE layer can support multiple application layers. In addition, an SE layer dedicated to each application layer can be defined. For example, to provide V2X services, the application layers 270 and 275 can be V2X application layers. In addition, to perform operations of the V2X application layer, the SE layers 280 and 285 can be defined as V2X layers. Hereinafter, to provide V2X services, the application layers 270 and 275 can be interchanged with the V2X application layer, and the SE layers 280 and 285 can be interchanged with the V2X layer.

[0072] The SE layers 280 and 285 can provide a data transfer function on the link established for the direct communication 140 between user equipment 110 and user equipment 120. The SE layers 280 and 285 can include Internet Protocol (IP), non - IP, and transport protocols (e.g., Transmission Control Protocol (TCP) or User Datagram Protocol (UDP)) to send messages.

[0073] According to some embodiments of the present disclosure, user equipments 110 and 120 can obtain the information shown in Table 1 from the network through the process shown in FIG. 8, and store the information to use V2X services. The SE layers 280 and 285 can use the stored information.

[0074]

Table 1

[0075]

[0076] The above table is translated as follows:

[0077]

[0078]

[0079] After the establishment of the link for the direct communication 140 between the user equipment 110 and the user equipment 120, the SDAP layers 290 and 295 can be used to transmit data over the established link. For example, when the link for the direct communication 140 between the user equipment 110 and the user equipment 120 is established and then data (e.g., PC5 unicast communication or PC5 multicast) is transmitted over the established link, the SDAP layers 290 and 295 can be used for message transmission. In addition, when data (e.g., PC5 broadcast communication) is transmitted without establishing the link for the direct communication 140 between the user equipment 110 and the user equipment 120, the SDAP layers 290 and 295 may not be used for message transmission.

[0080] The PC5 signaling protocol layers 210 and 215 according to certain embodiments of the present disclosure may include functions provided by the SE layers 280 and 285. Alternatively, the PC5 signaling protocol layers 210 and 215 may interact with the SE layers 280 and 285 for link establishment and / or link maintenance.

[0081] Figure 3 An example of a process for direct communication link establishment (ProSe link establishment) according to certain embodiments of the present disclosure is shown.

[0082] Reference Figure 3 to a non-limiting example, in order to perform the direct communication link establishment process, the user equipment 110, 115, 120, and 125 may obtain destination layer-2 ID (corresponding to the "destination layer-2 ID for PC5 unicast link establishment" in Table 1) information for link establishment from the network by using Figure 8a , Figure 8b and Figure 8c the processes shown, and store the destination layer-2 ID information. The destination layer-2 ID for link establishment may be set to different values according to the application layer, the applications supported by the application layer, or the message types supported by the application layer. Alternatively, the destination layer-2 ID for link establishment may be set to a value regardless of the application layer, the applications supported by the application layer, or the message types supported by the application layer.

[0083] Reference Figure 3For illustrative examples, user devices 115, 120, and 125 can determine the destination layer-2 ID for link establishment (corresponding to the "Destination layer-2 ID for PC5 unicast link establishment" in Table 1) among the stored V2X service policy parameters (the information shown in Table 1) to receive the establishment signaling message for the direct communication link. In operation 310, when user devices 115, 120, and 125 receive the establishment signaling message for the direct communication link (which uses the destination layer-2 ID for link establishment as the destination), user devices 115, 120, and 125 can process the establishment signaling message. The establishment signaling message for the direct communication link can use the address of the destination layer-2 ID as the destination.

[0084] In operation 315, the application layer 270 of user device 110 that wants to perform an application operation can provide to the SE layer 280 at least one of an "application message" (hereinafter referred to as "message" and interchangeable with "service data", "data", or "application data") generated by the application layer 270, a "message type" indicating the message type (interchangeable with "service type"), a communication mode indicating the communication method of the message (e.g., broadcast, multicast, unicast, etc.), an "application layer ID" (application layer identifier) of user device 110, an "application layer ID" (application layer identifier) of user device 120, or a "quality of service (QoS) requirement". In vehicle communication, the message type can be PSID, ITS-AID, etc.

[0085] In operation 315, the SE layer 280 of user device 110 can determine whether to execute the link establishment process based on the communication mode information received from the application layer 270. For example, in operation 320, when the communication mode received from the application layer 270 is PC5 unicast, the SE layer 280 can determine to execute the link establishment process and perform the following operations.

[0086] The SE layer 280 of the user equipment 110 may allocate a flow identifier (ID) for generating a unicast link (which may be interchangeable with a QoS flow identifier (QFI) or a PC5 flow identifier (PFI), hereinafter referred to as PFI). The PFI may be allocated as a unique value in the user equipment 110. The SE layer 280 may convert the QoS requirements received from the application layer 270 into PC5 5QI (PQI) information that can be used in the AS layer. In addition, the SE layer 280 may determine whether the PQI information is available based on the V2X service policy parameters (e.g., the list of V2X services that allow the use of (multiple) specific PQIs in Table 1). For example, the V2X service policy parameters (e.g., the list of V2X services that allow the use of (multiple) specific PQIs in Table 1) may include a list of V2X services that allow the use of high QoS (PQI), and allow the V2X services included in the list of V2X services to use high PQI values.

[0087] The SE layer 280 may generate a direct communication request message for unicast link establishment. The direct communication request message may include at least one of an "application message", a "message type", the "application layer ID" of the user equipment 110, "QoS requirements", "PQI", or "PFI".

[0088] The SE layer 280 may allocate by itself the layer-2 ID of the user equipment 110 that will be used for the PC5 unicast link to be generated, and set the layer-2 ID allocated by the user equipment 110 as the source layer-2 ID of the direct communication request message. The SE layer 280 may set the stored destination layer-2 ID address for link establishment (the "destination layer-2 ID for PC5 unicast link establishment" in Table 1) as the destination layer-2 ID of the direct communication request message.

[0089] In various embodiments, the SE layer 280 may generate a link profile (which may be interchangeable with a unicast link profile, a PC5 link profile, or a PC5 unicast link profile) for the PC5 unicast link to be established. The link profile may include at least one of the "application layer ID" of the user equipment 110, the "application layer ID" of the user equipment 120, the "layer-2 ID" of the user equipment 110 allocated by the user equipment 110, "QoS requirements", "PQI", or "PFI" information, and may be identified as a PFI that is a unique value in the user equipment 110.

[0090] The SE layer 280 may send a direct communication request message, the source layer-2 ID of the direct communication request message (i.e., the layer-2 ID of the user equipment 110 assigned by the SE layer 280), the destination layer-2 ID of the direct communication request message (i.e., the destination layer-2 ID address stored in the user equipment 110 for link establishment), and information about the direct communication link to be established (e.g., the assigned PFI information) to the PDCP layer 230. The SE layer 280 may indicate to the PDCP layer 230 that the communication mode of the direct communication request message is PC5 broadcast. In operation 325, the user equipment 110 may send the direct communication request message via the PDCP layer 230, RLC layer 240, MAC layer 250, and PHY layer 260 by using a broadcast scheme.

[0091] In operation 325, the user equipments 115, 120, and 125 near the user equipment 110 may receive the direct communication request message sent from the user equipment 110. Each of the user equipments 115, 120, and 125 may deliver the direct communication request message to the SE layer via the PHY layer, MAC layer, RLC layer, and PDCP layer of each of the user equipments 115, 120, and 125. The SE layer may receive the direct communication request message, check the destination address of the direct communication request message, and determine the processing method of the direct communication request message. When the destination address of the direct communication request message is the destination layer-2 ID address for link establishment stored in the corresponding user equipment (see operation 310), the SE layer may select the application layer to which the direct communication request message is to be delivered based on at least one of the destination layer-2 ID address of the direct communication request message, the "message type" included in the direct communication request message, or the "application layer ID" information of the user equipment included in the direct communication request message, and deliver the direct communication request message to the selected application layer.

[0092] When the application layer 275 of the user equipment 120 receives the direct communication request message, the application layer 275 may determine a response to the direct communication request message based on the "application message", "message type", "application layer ID" of the user equipment 110, "application layer ID" of the user equipment 120, etc. included in the direct communication request message. In operation 330, when the application layer 275 of the user equipment 120 determines to approve the direct communication request, the application layer 275 may provide the SE layer 285 with at least one of the "application message" (hereinafter referred to as "message") generated by the application layer 275, the "message type" indicating the message type, the communication mode (e.g., broadcast, multicast, unicast, etc.) indicating the communication method of the message, the "application layer ID" of the user equipment 110, the "application layer ID" of the user equipment 120, or the "QoS requirement".

[0093] In operation 335, the SE layer 285 of the user equipment 120 may determine to perform a link establishment process and perform the following operations.

[0094] The SE layer 285 of the user equipment 120 may allocate a PFI for generating a unicast link or use the PFI received in operation 325. The PFI may be allocated as a unique value in the user equipment 110. The SE layer 285 may convert the QoS requirements received from the application layer 275 into PQI (PC5 5QI) information that can be used in the AS layer.

[0095] The SE layer 285 of the user equipment 120 may generate a direct communication response message for unicast link establishment. The direct communication response message may include at least one of "application message", "message type", "application layer ID" of the user equipment 110, "application layer ID" of the user equipment 120, "QoS requirements", "PQI", or "PFI".

[0096] The SE layer 285 of the user equipment 120 may allocate by itself the layer-2 ID of the user equipment 120 that will be used for the PC5 unicast link to be generated and set the layer-2 ID allocated by the user equipment 120 as the source layer-2 ID of the direct communication response message. The SE layer 285 may set the source layer-2 ID of the direct communication request message received in operation 325 as the destination layer-2 ID of the direct communication response message.

[0097] The SE layer 285 of the user equipment 120 may generate a link profile (which may also be interchangeable with a unicast link profile, a PC5 link profile, or a PC5 unicast link profile) for the PC5 unicast link to be established. The link profile may include at least one of "application layer ID" and "layer-2 ID" of the user equipment 110 (i.e., the source layer-2 ID of the direct communication request message received in operation 325), "application layer ID" and "layer-2 ID" of the user equipment 120 (allocated by the user equipment 120), "QoS requirements", "PQI", or "PFI" information, and the link profile may be identified as a PFI that is a unique value in the user equipment 120.

[0098] The SE layer 285 may send a direct communication response message, the source layer-2 ID of the direct communication response message (i.e., the layer-2 ID of the user equipment 120 assigned by the SE layer 285), the destination layer-2 ID of the direct communication response message (i.e., the source layer-2 ID of the direct communication request message received in operation 325), and information about the direct communication link to be established (e.g., information about the assigned PFI) to the PDCP layer 235 or the RRC layer 225. At this time, the SE layer 285 may instruct the PDCP layer 235 or the RRC layer 225 to configure the communication mode of the direct communication response message as PC5 unicast and configure the message type as signaling. When the SE layer 285 sends a direct communication response message through the RRC layer 225, the direct communication response message may be included in the RRC message and sent to the user equipment 110. The MAC layer 255 of the user equipment 120 may configure the logical channel ID (LCID) of the MAC header for sending the direct communication response message with a value indicating a signaling message. In operation 340, the direct communication response message may be sent to the user equipment 110 via the PHY layer 265.

[0099] In various embodiments according to the present disclosure, the SE layer 280 of the user equipment 110 receives a direct communication response message, and the SE layer 280 may notify the application layer 270 that the direct communication link has been established. At this time, the SE layer 280 of the user equipment 110 may notify the application layer 270 of information related to the direct communication link (e.g., PFI, etc.) together. In addition, the SE layer 280 may notify the PDCP layer 230 or the RRC layer 220 of information related to the direct communication link that has been fully established (e.g., information about the assigned PFI). The SE layer 280 may update the link profile generated in operation 320 based on the direct communication response message. For example, the SE layer 280 may store the destination layer-2 ID of the direct communication response message received in operation 340 as the "layer-2 ID" of the user equipment 120. In addition, when the "application layer ID", "QoS requirement", "PQI", and "PFI" information of the user equipment 120 included in the direct communication response message received in operation 340 do not match the link profile generated in operation 320, the SE layer 280 may update the link profile to the information received in operation 340.

[0100] Figure 4 An example of a process for changing a user equipment identifier according to certain embodiments of the present disclosure is shown. More specifically, Figure 4 An example of a process for changing the layer-2 ID according to certain embodiments of the present disclosure is shown, but is not limited thereto.

[0101] Refer to Figure 4As a non-limiting example, user equipment 110 and user equipment 120 can complete the establishment of a direct communication link through the above direct communication link establishment process. User equipment 110 and 120 can generate a link profile during the direct communication link establishment process and store the layer-2 ID information of user equipment 110 and 120 that will be used for the direct communication link.

[0102] In operation 410, user equipment 120 can determine the layer-2 ID address of user equipment 120 among the stored link profile information to receive a direct communication link maintenance signaling message. The direct communication link maintenance signaling message can have the layer-2 ID address of user equipment 120 determined in operation 410 as the destination.

[0103] In some embodiments, the application layer 270 of user equipment 110 can change the currently used application layer ID of user equipment 110. In operation 420, the application layer 270 can transmit the changed application layer ID and the direct communication link information (such as service type (such as PSID or ITS-AID), PFI, etc.) in which the application layer ID is used to the SE layer 280.

[0104] In operation 430, when the SE layer 280 receives the changed application layer ID from the application layer in operation 420, or when user equipment 110 requests privacy support based on the service type currently being used according to the policies / parameters stored in user equipment 110, the SE layer 280 can determine to perform the process of changing the layer-2 ID at regular time intervals and perform the following operations.

[0105] The SE layer 280 of user equipment 110 can allocate by itself a new layer-2 ID of user equipment 110 that will be newly used in the direct communication link associated with the PFI. The SE layer 280 can store the new layer-2 ID of user equipment 110 in the link profile associated with the PFI. When the SE layer 280 receives the newly allocated application layer ID from the application layer 270 in operation 420, the SE layer 280 can store the newly allocated application layer ID of user equipment 110 in the link profile associated with the PFI.

[0106] In some embodiments, the SE layer 280 can generate a link layer identifier update request message for changing the layer-2 ID. The link layer identifier update request message can include at least one of the newly allocated layer-2 ID of user equipment 110, the newly allocated application layer ID of user equipment 110 (when the SE layer 280 receives the newly allocated application layer ID from the application layer 270 in operation 420), the previously used layer-2 ID of user equipment 110, the previously used or currently used application layer ID of user equipment 110, or the "PFI" representing the corresponding direct communication link.

[0107] The SE layer 280 of the user equipment 110 may set the source layer-2 ID of the link layer identifier update request message to the previously used layer-2 ID of the user equipment 110 or the newly allocated layer-2 ID of the user equipment 110. In addition, the SE layer 280 of the user equipment 110 may set the destination layer-2 ID of the link layer identifier update request message to the layer-2 ID of the user equipment 120 stored in the link profile associated with the PFI.

[0108] The SE layer 280 may send a link layer identifier update request message, the source layer-2 ID of the link layer identifier update request message, the destination layer-2 ID of the link layer identifier update request message, and the PFI information related to the link layer identifier update request message to the RRC layer 220. At this time, the SE layer 280 may indicate PC5 unicast as the communication mode of the link layer identifier update request message and indicate signaling as the message type. The link layer identifier update request message may be included in the RRC message and sent to the user equipment 120. The MAC layer 250 of the user equipment 110 may set the logical channel ID of the MAC header for sending the link layer identifier update request message to a value representing a signaling message. The value of the logical channel ID used in the signaling message may be different from the value of the logical channel ID used in the data message. In operation 440, the link layer identifier update request message may be sent to the user equipment 120 via the PHY layer 260.

[0109] When the MAC layer 255 of the user equipment 120 receives the link layer identifier update request message, the MAC layer 255 may check the logical channel ID of the MAC header of the link layer identifier update request message to determine that the link layer identifier update request message is a signaling message and transmit the link layer identifier update request message to the SE layer 285 via the RRC layer 225. The SE layer 285 may check the destination layer-2 ID and / or the PFI information of the link layer identifier update request message to determine that the link layer identifier update request message is a message for the direct communication link generated through the above process. In addition, in operation 450, the SE layer 285 of the user equipment 120 may determine that the received link layer identifier update request message is a signaling message depending on whether the link layer identifier update request message is received from the RRC layer 225 and perform the following operations.

[0110] The SE layer 285 may update the link profile information based on the information in the received link layer identifier update request message. For example, the SE layer 285 of the user equipment 120 may check the PFI included in the link layer identifier update request message and store the newly assigned layer-2 ID of the user equipment 110 included in the link layer identifier update request message in the link profile associated with the PFI and stored in the user equipment 120. When the newly assigned application layer ID is included in the link layer identifier update request message, the SE layer 285 may store the newly assigned application layer ID of the user equipment 110 included in the link layer identifier update request message in the link profile associated with the PFI, and then notify the application layer 275 that the application layer ID of the user equipment 110 for direct communication link establishment has changed. At this time, the SE layer 280 of the user equipment 110 may notify the application layer 270 of the information related to the direct communication link (e.g., PFI, etc.) together.

[0111] In various embodiments according to the present disclosure, the SE layer 285 of the user equipment 120 may generate a link layer identifier update response message. The link layer identifier update response message may include information notifying that the user equipment 120 has received the link layer identifier update request message and will use the newly assigned layer-2 ID and / or newly assigned application layer ID of the user equipment 110 for subsequent direct communication, or at least one of the PFIs used in the corresponding direct communication link.

[0112] When the user equipment 120 determines to change the ID used by the user equipment 120, the SE layer 285 may assign a new layer-2 ID for the user equipment 120 by itself and include the new layer-2 ID of the user equipment 120 in the link layer identifier update response message. In addition, when the SE layer 285 receives a new application layer ID from the application layer 275, the SE layer 285 may include the new application layer ID of the user equipment 120 in the link layer identifier update response message. The SE layer 285 may store the new layer-2 ID and / or new application layer ID of the user equipment 120 in the link profile associated with the PFI.

[0113] The SE layer 285 of the user equipment 120 may set the source layer-2 ID of the link layer identifier update response message to the new layer-2 ID currently used by the user equipment 120, and this new layer-2 ID is stored in the link profile associated with the PFI. In addition, the SE layer 285 of the user equipment 120 may set the destination layer-2 ID of the link layer identifier update response message to the new layer-2 ID currently used by the user equipment 110, and this new layer-2 ID is stored in the link profile associated with the PFI.

[0114] The SE layer 285 may send a link layer identifier update response message, the source layer-2 ID of the link layer identifier update response message, the destination layer-2 ID of the link layer identifier update response message, and PFI information associated with the link layer identifier update response message to the RRC layer 225. At this time, the SE layer 285 may instruct the RRC layer 225 to configure the communication mode of the link layer identifier update response message as PC5 unicast and configure the message type as signaling. The link layer identifier update response message may be included in the RRC message and sent to the user equipment 110. The MAC layer 255 of the user equipment 120 may set the logical channel ID of the MAC header for sending the link layer identifier update response message to a value indicating a signaling message. The value of the logical channel ID used in the signaling message may be different from the value of the logical channel ID used in the data message. In operation 460, the link layer identifier update response message may be sent to the user equipment 110 via the PHY layer 265.

[0115] The user equipment 120 may use the new IDs of the user equipment 110 and 120 (the new layer-2 ID and / or new application layer ID of the user equipment 110 and the new layer-2 ID and / or new application layer ID of the user equipment 120) to perform subsequent direct communication (signaling and message transmission) associated with the PFI.

[0116] When the MAC layer 250 of the user equipment 110 receives the link layer identifier update response message, the MAC layer 250 of the user equipment 110 may check the logical channel ID of the MAC header of the link layer identifier update response message to determine that the received link layer identifier update response message is a signaling message and transmit the link layer identifier update response message to the SE layer 280 via the RRC layer 220. The SE layer 280 may determine whether the link layer identifier update response message is a message generated for the direct communication link through the above process based on the destination layer-2 ID and / or PFI information of the received link layer identifier update response message. In addition, depending on whether the link layer identifier update response message is received from the RRC layer 220, the SE layer 280 of the user equipment 110 may determine that the received link layer identifier update response message is a signaling message. The SE layer 280 may use the new IDs of the user equipment 110 and 120 (e.g., the new layer-2 ID and / or new application layer ID of the user equipment 110 and the new layer-2 ID and / or new application layer ID of the user equipment 120) to perform signaling and message transmission for direct communication associated with the PFI. When the user equipment 120 includes new ID information (e.g., the new layer-2 ID and / or new application layer ID of the user equipment 120) in the link layer identifier update response message, the SE layer 280 may store the new ID information of the user equipment 120 in the link profile associated with the PFI.

[0117] User equipments 110 and 120 may update QoS parameters (e.g., PQI) for direct communication associated with the PFI by a method similar to the Figure 4 process shown. To update the QoS parameters, a link layer identifier update request message or a link layer identifier update response message may be used as a signaling message. Another signaling message (e.g., a QoS parameter update request message or a QoS parameter update response message) or a signaling message capable of being used for ID update and QoS parameter update of the user equipment (e.g., a ProSe link update request / response message) may be used as a signaling message.

[0118] Figure 5 An example of a process for releasing a direct communication link according to certain embodiments of the present disclosure is shown.

[0119] Referring to Figure 5 a non-limiting example of, user equipments 110 and 120 may complete the establishment of a direct communication link through the above process. User equipments 110 and 120 may generate a link profile during the direct communication link establishment process and store the layer-2 ID information of user equipments 110 and 120 that will be used for the direct communication link.

[0120] In operation 410, user equipment 120 may determine the layer-2 ID address of user equipment 120 from the stored link profile information to receive a direct communication link maintenance signaling message. The direct communication link maintenance signaling message may have the layer-2 ID address of user equipment 120 determined in operation 410 as the destination.

[0121] In operation 510, the application layer 270 of user equipment 110 may request to release the direct communication link associated with the PFI.

[0122] In operation 520, the SE layer 280 of user equipment 110 may perform the following operations to release the direct communication link.

[0123] The SE layer 280 may generate a direct communication release request message. The SE layer 280 of user equipment 110 may set the source layer-2 ID of the direct communication release request message to the currently used layer-2 ID of user equipment 110, which is stored in the link profile associated with the PFI. In addition, the SE layer 280 may set the destination layer-2 ID of the direct communication release request message to the currently used layer-2 ID of user equipment 120, which is stored in the link profile associated with the PFI.

[0124] The SE layer 280 may send a direct communication release request message, the source layer-2 ID of the direct communication release request message, the destination layer-2 ID of the direct communication release request message, and PFI information associated with the direct communication release request message to the RRC layer 220. At this time, the SE layer 280 may instruct the RRC layer 220 to configure the communication mode of the direct communication release request message as PC5 unicast and configure the message type as signaling. The direct communication release request message may be included in the RRC message and sent to the user equipment 120. The MAC layer 250 of the user equipment 110 may set the logical channel ID of the MAC header for sending the direct communication release request message to a value indicating a signaling message. The value of the logical channel ID used in the signaling message may be different from the value of the logical channel ID used in the data message. In operation 530, the direct communication release request message may be sent to the user equipment 120 via the PHY layer 260.

[0125] In various embodiments, when the MAC layer 255 of the user equipment 120 receives the direct communication release request message, the MAC layer 255 may determine whether the direct communication release request message is a signaling message based on the logical channel ID of the MAC header of the direct communication release request message, and transmit the direct communication release request message to the SE layer 285 via the RRC layer 225. The SE layer 285 may determine whether the direct communication release request message is a message for the direct communication link based on the destination layer-2 ID and / or PFI information of the direct communication release request message. In addition, in operation 540, the SE layer 285 of the user equipment 120 may determine that the direct communication release request message is a signaling message depending on whether the direct communication release request message is received from the RRC layer 225, and perform the following operations.

[0126] The SE layer 285 may notify the application layer 275 that the direct communication link associated with the PFI has been released. The SE layer 285 may generate a direct communication release response message. The SE layer 285 of the user equipment 120 may set the source layer-2 ID of the direct communication release response message to the currently used layer-2 ID of the user equipment 120, which is stored in the link profile associated with the PFI. In addition, the SE layer 285 may set the destination layer-2 ID of the direct communication release response message to the currently used layer-2 ID of the user equipment 110, which is stored in the link profile associated with the PFI.

[0127] In various embodiments, the SE layer 285 may send a direct communication release response message, the source layer-2 ID of the direct communication release response message, the destination layer-2 ID of the direct communication release response message, and PFI information associated with the direct communication release response message to the RRC layer 225. At this time, the SE layer 285 may instruct the RRC layer 225 to configure the communication mode of the direct communication release response message as PC5 unicast and configure the message type as signaling. The direct communication release response message may be included in the RRC message and sent to the user equipment 110. The MAC layer 255 of the user equipment 120 may set the logical channel ID of the MAC header for sending the direct communication release response message to a value indicating a signaling message. The value of the logical channel ID used in the signaling message may be different from the value of the logical channel ID used in the data message. In operation 550, the direct communication release response message may be sent to the user equipment 110 via the PHY layer 265.

[0128] The SE layer 285 may delete the link profile information associated with the PFI.

[0129] When the MAC layer 250 of the user equipment 110 receives the direct communication release response message, the MAC layer 250 may determine whether the direct communication release response message is a signaling message based on the logical channel ID of the MAC header of the direct communication release response message, and transmit the direct communication release response message to the SE layer 280 via the RRC layer 220. The SE layer 280 may determine whether the direct communication release response message is a message for the direct communication link generated through the above process based on the destination layer-2 ID and / or PFI information of the direct communication release response message. In addition, depending on whether the direct communication release response message is received from the RRC layer 220, the SE layer 280 of the user equipment 110 may determine that the direct communication release response message is a signaling message. The SE layer 280 may notify the application layer 270 that the direct communication link associated with the PFI has been released. The SE layer 280 may delete the link profile information associated with the PFI.

[0130] Figure 6 An example of a process for releasing a direct communication link according to various embodiments of the present disclosure is shown.

[0131] Referring Figure 6 to a non-limiting example, the user equipment 110 and the user equipment 120 may complete the direct communication link establishment through the above process. The user equipment 110 and 120 may generate a link profile during the direct communication link establishment process and store the layer-2 ID information of the user equipment 110 and 120 that will be used for the direct communication link.

[0132] In operation 610, the SE layers 280 and 285 of the user equipments 110 and 120 can check the current status information of the direct communication link associated with the PFI by the following method.

[0133] First, the SE layers 280 and 285 can receive reports on the current status information of the direct communication link associated with the PFI from the RRC layers 220 and 225, the PDCP layers 230 and 235, the RLC layers 240 and 245, or the MAC layers 250 and 255. When the received report on the current status information indicates a link failure, the SE layers 280 and 285 can determine that communication via the direct communication link established between the user equipments 120 and 110 is currently impossible.

[0134] Alternatively, the SE layers 280 and 285 can use the Keep-alive function. When there is no response to the Keep-alive request messages from the user equipments 120 and 110 within a preset time period, the SE layers 280 and 285 can determine that communication via the direct communication link established between the user equipments 120 and 110 is currently impossible.

[0135] When the SE layers 280 and 285 can determine via the above methods that communication via the direct communication link associated with the PFI is currently impossible, the SE layers 280 and 285 can notify the application layers 270 and 275 that the direct communication link associated with the PFI has been released. Then, the SE layers 280 and 285 can delete the link profile information associated with the PFI.

[0136] Figure 7 An example of a data transmission process using a direct communication link according to certain embodiments of the present disclosure is shown.

[0137] Reference Figure 7 As a non-limiting example of, the user equipments 110 and 120 can complete the direct communication link establishment through the above process. The user equipments 110 and 120 can generate a link profile during the direct communication link establishment process and store the layer-2 ID information of the user equipments 110 and 120 that will be used for the direct communication link.

[0138] In various embodiments, in operation 710, the user equipment 120 can determine the layer-2 ID address of the user equipment 120 from the link profile information to receive data on the stored direct communication link. The data message transmitted on the direct communication link can use the layer-2 ID address of the user equipment 120 determined in operation 710 as the destination.

[0139] In operation 720, the application layer 270 of the user equipment 110 may send to the SE layer 280 at least one of an "application message" generated by the application layer 270, a "PFI" indicating a direct communication link over which the message is transmitted, a "message type" indicating the type of the message, a "communication mode" indicating the communication method of the message (e.g., broadcast, multicast, unicast, etc.), an "application layer ID" of the user equipment 110, an "application layer ID" of the user equipment 120, or a "QoS requirement".

[0140] In some embodiments, the SE layer 280 may check the link profile information associated with the PFI received in operation 720. To send the "application data" received in operation 720, in operation 730, the SE layer 280 may set the source layer-2 ID to the currently used layer-2 ID of the user equipment 110, which is stored in the link profile associated with the PFI, and set the destination layer-2 ID to the currently used layer-2 ID of the user equipment 120, which is stored in the link profile associated with the PFI.

[0141] The SE layer 280 may send to the SDAP layer 290 at least one of the "application data", the "source layer-2 ID" determined in operation 730, the "destination layer-2 ID" determined in operation 730, or the associated "PFI" information. The SDAP layer 290 of the user equipment 110 may send a message by using the received information associated with the PFI. The MAC layer 250 may set the logical channel ID of the MAC header for sending the message to a value indicating a data message. The value of the logical channel ID used in the data message may be different from the value of the logical channel ID used in the signaling message. In operation 740, the "application data" may be sent to the user equipment 120 via the PHY layer 260.

[0142] When the MAC layer 255 of the user equipment 120 receives the "application data", the MAC layer 255 may determine that the received message is a data message based on the logical channel ID of the MAC header of the received message, and transmit the message to the SE layer 285 via the SDAP layer 295. The SE layer 285 may determine whether the received message is a message for a direct communication link generated through the above process based on the destination layer-2 ID and / or PFI information of the received message. In addition, the SE layer 285 of the user equipment 120 may determine that the received message is a data message depending on whether a message is received from the SDAP layer 295.

[0143] According to various embodiments, the SE layer 285 may transfer the received "application data" to the application layer 275. In addition, the SE layer 285 may transfer direct communication link information associated with the "application data" to the application layer 275 (e.g., PFI, PSID, ITS-AID, application layer ID, etc. of the user equipments 110 and 120).

[0144] Figure 8a An example of a process performed by a user equipment during an initial registration process to obtain service information from a network according to certain embodiments of the present disclosure is shown.

[0145] Referring Figure 8a to the non-limiting example of, when the AMF 811 receives a registration request message from the user equipment 110 via the (R)AN 810 in operations 823 and 826, in operation 829, the AMF 811 may request the UDM 813 to send UE subscription information and obtain the UE subscription information from the UDM 813. In addition, in operation 832, the AMF 811 may request the PCF 812 to send policy information associated with the user equipment 110.

[0146] At this time, in operation 823, the user equipment 110 may include information about functions supported by the user equipment 110 and / or information about a UE policy container (e.g., V2X policy) in the registration request message, and send the obtained registration request message to the (R)AN 810. In operation 826, the (R)AN 810 may transfer the registration request message received from the user equipment 110 to the AMF 811. When the user equipment 110 supports V2X services, information indicating that the user equipment 110 supports V2X services may be included in the UE capability information and provided to the AMF 811. In addition, information indicating that the user equipment 110 supports PC5 communication may be included in the UE LTE PC5 capability information and the UE NR PC5 capability information and provided to the AMF 811.

[0147] According to some embodiments, in operation 829, the AMF 811 may request the UDM 813 to send UE subscription information. In operation 829, the UDM 813 may send a UE subscription information request message to the UDR 814. The UE subscription information request message may include information indicating the user equipment 110 (e.g., the SUPI, 5G-GUTI, IMSI, etc. of the user equipment 110). The UDR 814 may send a DM query response message including the UE subscription information of the user equipment 110 to the UDM 813. When the UDM 813 receives the UE subscription information, the UDM 813 may send a UE subscription response message to the AMF 811. The UE subscription response message may include at least one of the V2X service authentication information of the user equipment 110, the V2X capabilities of the user equipment 110, the PC5 LTE capabilities of the user equipment 110, the PC5 NR capabilities of the user equipment 110, or information related to the subscription of the user equipment 110.

[0148] When the AMF 811 determines that the user equipment 110 supports V2X services based on the UE capabilities information received from the user equipment 110, the AMF 811 may select a PCF 812 that supports V2X services. In operation 832, the AMF 811 may request the selected PCF 812 to send policy information related to the user equipment 110. In operation 832, the message may include information about the UE policy container (V2X policy) received by the AMF 811 from the user equipment 110.

[0149] In some embodiments according to the present disclosure, the PCF 812 may obtain V2X service parameters to be applied to the user equipment 110 from the UDR 814 by various methods. First, in operation 820, when the V2X service parameters need to be updated, the UDR 814 may provide the V2X service parameters to the PCF 812. In addition, in operation 832, the PCF 812 may request the UDR 814 to send the V2X service parameters and obtain the V2X service parameters from the UDR 814.

[0150] The V2X service parameters provided from the UDR 814 to the PCF 812 may include the service policy / parameter information described in the present disclosure.

[0151] Meanwhile, in operation 832, the PCF 812 may receive the subscriber information of the user equipment 110 and information about the functions supported by the user equipment 110. In operation 832, the AMF 811 may provide the UE capabilities information and / or UE subscription information obtained from the UDM 813 to the PCF 812.

[0152] In operation 832, the PCF 812 may provide information about the policy to be applied to the user equipment 110 to the AMF 811, and the V2X service parameters received from the UDR 814 may be included in the information about the policy.

[0153] In some embodiments, in operation 835, the AMF 811 may include the V2X service parameters received from the PCF 812 in a registration acceptance message and transmit the resulting registration acceptance message to the user equipment 110. Alternatively, in operation 838, the AMF 811 may transmit the V2X service parameters received from the PCF 812 to the user equipment 110 through a preset process. The V2X service parameters included in the registration acceptance message (operation 835) or the UE policy transmission message (operation 838) may include at least one of the service policy / parameter information described in the present disclosure.

[0154] Figure 8b A process performed by a user equipment in response to a request from a network to obtain service information according to some embodiments of the present disclosure is shown.

[0155] More specifically, Figure 8b An example of a method performed by the user equipment 110 to obtain service policy / parameter information (e.g., the V2X service policy parameters shown in Table 1) according to some embodiments is shown, but is not limited thereto. Referring to Figure 8b a non-limiting example, the user equipment 110 may obtain a UE policy by using a UE configuration update process.

[0156] Referring again to Figure 8b the illustrative example of, in operation 843, the PCF 812 may determine to update the UE policy. Similar to Figure 8a operation 820 of, the PCF 812 may have received and stored the updated service policy / parameter information (e.g., the V2X service policy parameters shown in Table 1) of the user equipment 110 from the UDR 814.

[0157] The PCF 812 may determine whether the UE policy needs to be updated during the initial registration process of the user equipment 110 or when the network triggers an update of the UE policy after the initial registration of the user equipment 110, as Figure 8aAs shown. For example, during the initial registration process, the PCF 812 can determine whether the UE policy needs to be updated based on the UE policy container (e.g., V2X policy) information received from the AMF 811 and the policy information associated with the access selection and PDU selection of the user equipment 110 (e.g., included in the Npcf_UEPolicyControl_Create request). Alternatively, when an event occurs, for example, when the location of the user equipment 110 changes, or when the subscription information of the user equipment 110 (e.g., the slice service (subscribed S-NSSAI) subscribed by the user equipment 110) changes, the PCF 812 can determine whether the UE policy needs to be changed. In addition, the PCF 812 can determine to transmit the service policy / parameter information (e.g., the V2X service policy parameters shown in Table 1) received from the UDR 814 to the user equipment 110, as described above in Figure 8a operation 832 as described.

[0158] In operation 845, the PCF 812 can transmit the service policy / parameter information (e.g., the V2X service policy parameters shown in Table 1) to the AMF 811. When the V2X service policy parameters shown in Table 1 are transmitted as the service policy / parameter information, the service policy / parameter information can include at least one of the V2X service policy parameters shown in Table 1. In operation 845, the service policy / parameter information (e.g., the V2X service policy parameters shown in Table 1) according to certain embodiments of the present disclosure can be included in the Namf_Communication_N1N2MessageTransfer message and sent to the AMF 811. The Namf_Communication_N1N2MessageTransfer message can include SUPI, UE policy container, etc.

[0159] In some embodiments, when the user equipment 110 has been registered in the network and is in a service receivable state, in operation 848, the AMF 811 may determine to transmit the UE policy received from the PCF 812 to the user equipment 110. When the user equipment 110 has been registered in any one of 3GPP and non-3GPP accesses, the AMF 811 may transmit the UE policy to the user equipment 110 through the access to which the user equipment 110 has been registered and connected. When the user equipment 110 has been registered in both 3GPP and non-3GPP accesses and is connectable to both 3GPP and non-3GPP accesses, the AMF 811 may select an access from 3GPP and non-3GPP accesses according to the local policy of the AMF 811, and transmit the UE policy to the user equipment 110 through the selected access. In operation 856, when the user equipment 110 has never been registered in any one of 3GPP and non-3GPP accesses or is prohibited from connecting to any one of 3GPP and non-3GPP accesses, the AMF 811 may notify the PCF 812 that the transmission of the UE policy has failed (e.g., through Namf_Communication_N1N2TransferFailureNotification). When the AMF 811 determines to transmit the UE policy to the user equipment 110 through 3GPP access and the user equipment 110 is in the CM-IDLE state, the AMF 811 may send a paging request message to the user equipment 110 to start a paging process (network-triggered service request). When the user equipment 110 receives the paging request message, the user equipment 110 may execute the paging process.

[0160] In operation 851, the AMF 811 may transmit the UE policy to the user equipment 110. When the UE policy includes V2X services, the UE policy may include at least one of the V2X service policy parameters shown in Table 1.

[0161] In operation 853, when the user equipment 110 receives information about the UE policy, the user equipment 110 may store the information therein and send a response message notifying that the information has been received to the AMF 811.

[0162] In certain embodiments, in operation 856, the AMF 811 may notify the PCF 812 that the service policy / parameter information (e.g., the V2X service policy parameters shown in Table 1) has been sent to the user equipment 110. At this time, the Namf_N1MessageNotify message may be used. Then, the PCF 812 may maintain the UE policy, or notify the UDR 814 of the updated UE policy.

[0163] Figure 8cShows an example of a process performed by a user equipment in response to a request from the user equipment to obtain service information from a network, according to certain embodiments of the present disclosure.

[0164] More specifically, Figure 8c Shows an example of a method performed by user equipment 110 to obtain service policy / parameter information (e.g., the V2X service policy parameters shown in Table 1), according to various embodiments of the present disclosure. In Figure 8c a non-limiting example, user equipment 110 may trigger the acquisition of a UE policy to obtain a UE policy.

[0165] Referring to Figure 8c the illustrative example of, in operation 859, user equipment 110 may send a message requesting a UE policy to AMF 811. The message requesting a UE policy may be a UE policy provisioning request message, and the UE policy provisioning request message may include a UE policy container (e.g., a V2X policy).

[0166] In addition, in operation 862, AMF 811 may send a message requesting UE policy information to PCF 812. The message requesting UE policy information may be an Npcf_UEPolicyControl_Update request, and the message may include the UE policy container (e.g., a V2X policy) received from user equipment 110.

[0167] When PCF 812 receives the message requesting UE policy information, in operation 843, PCF 812 may determine whether the UE policy needs to be updated.

[0168] In some embodiments, Figure 8c operations 843, 845, 848, 851, 853, and 856 of Figure 8b may be similar to the corresponding operations described above with reference to

[0169] For example, in operation 845, PCF 812 may send information about the UE policy to AMF 811, and in operations 848 and 851, AMF 811 may determine to transmit the UE policy to user equipment 110 and then transmit the UE policy to user equipment 110. In addition, in operation 853, user equipment 110 may send a response message to AMF 811 in response to receiving the UE policy, and in operation 856, AMF 811 may send a message to PCF 812 regarding whether the transmission of the UE policy was successful.

[0170] As described above with reference to Figure 8a 、 Figure 8b and Figure 8cThe process performed by the user equipment 110 to obtain service parameters / policies from the network can be applied to other user equipment in the same manner.

[0171] Figure 9a An example of the configuration of a network entity according to certain embodiments of the present disclosure is shown in block diagram form.

[0172] Referring Figure 9a to a non-limiting example, network entities according to certain embodiments of the present disclosure may include (R)AN 810, AMF 811, PCF 812, UDM 813, and UDR 814. Additionally, network entities may include eNB, MME, S-GW, P-GW, PCRF, and HSS.

[0173] Referring Figure 9a to an illustrative example, a network entity may consist of a transceiver 900, a controller 910, and a storage device 920. The transceiver 900, controller 910, and storage device 920 of the network entity may operate according to the communication method of the network entity as described above. However, the components of the network entity are not limited to the above examples. For example, a network entity may include more or fewer components than those described above. Additionally, the transceiver 900, controller 910, and storage device 920 may be implemented in the form of a single chip. Further, the controller 910 may include at least one processor.

[0174] The transceiver 900 is a general term for the receiver 906 of the network entity and the transmitter 903 of the network entity, and can send and receive signals. The signals sent and received may include control information and data. To send and receive signals, the transceiver 900 may consist of an RF transmitter for up-converting the frequency of the signal to be sent and amplifying the signal, and an RF receiver for low-noise amplifying the received signal and down-converting the frequency of the received signal. However, the RF transmitter and RF receiver are specific embodiments of the transceiver 900, and the components of the transceiver 900 are not limited to the RF transmitter and RF receiver.

[0175] In some embodiments, the transceiver 900 may receive a signal through a wireless channel, output the signal to the controller 910, and send the signal output from the controller 910 through the wireless channel.

[0176] The storage device 920 may store programs and data required for the operation of the network entity. Additionally, the storage device 920 may store control information or data included in the signals obtained by the network entity. The controller 910 may be configured with a storage medium such as a read-only memory (ROM), a random access memory (RAM), a hard disk, a compact disc read-only memory (CD-ROM), and a digital versatile disc (DVD), or a combination of these storage media.

[0177] The controller 910 can control a series of processes such that network entities operate according to the above embodiments of the present disclosure. For example, the controller 910 can receive control signals and data signals via the transceiver 900 and process the received control signals and data signals. In addition, the controller 910 can transmit the processed control signals and data signals via the transceiver 900.

[0178] Figure 9b An example of the configuration of a user equipment according to certain embodiments of the present disclosure is shown in block diagram form.

[0179] More specifically, Figure 9b An example of the internal structure of user equipments 110 and 120 according to certain embodiments of the present disclosure is shown. The user equipment may include a transceiver 950, a controller 960, and a storage device 970.

[0180] The transceiver 950, the controller 960, and the storage device 970 of the user equipment can operate according to the communication method of the user equipment as described above. 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 those described above. In addition, the transceiver 950, the controller 960, and the storage device 970 can be implemented in the form of a single chip. In addition, the controller 960 may include at least one processor.

[0181] Referring to Figure 9b a non-limiting example, the transceiver 950 collectively refers to the receiver 956 of the user equipment and the transmitter 953 of the user equipment, and can send signals to and receive signals from the base station. The signals sent to and received from the base station may include control information and data. In order to send signals to and receive signals from the base station, the transceiver 950 may be composed of an RF transmitter for up-converting the frequency of the signal to be sent and amplifying the signal and an RF receiver for low-noise amplifying the received signal and down-converting the frequency of the received signal. However, the RF transmitter and the RF receiver are specific embodiments of the transceiver 950, and the components of the transceiver 950 are not limited to the RF transmitter and the RF receiver.

[0182] In addition, the transceiver 950 can receive signals via a wireless channel, output the signals to the controller 960, and send the signals output from the controller 960 via the wireless channel.

[0183] The storage device 970 can store programs and data required for the operation of the user equipment. In addition, the storage device 970 can store control information or data included in the signals acquired by the user equipment. The storage device 970 can be configured with storage media such as ROM, RAM, hard disk, CD-ROM, and DVD or a combination of these storage media.

[0184] The controller 960 may control a series of processes such that the user equipment operates according to the above-described embodiments of the present disclosure. For example, the controller 960 may receive control signals and data signals through the transceiver 950 and process the received control signals and data signals. In addition, the controller 960 may transmit the processed control signals and data signals through the transceiver 950.

[0185] According to some embodiments of the present disclosure, an apparatus and a method capable of effectively providing a one-to-one communication service in a wireless communication system may be provided.

[0186] Although the present disclosure has been described with various embodiments, various changes and modifications may be suggested to those skilled in the art. The present disclosure is intended to embrace such changes and modifications that fall within the scope of the appended claims.

Claims

1. A method for unicast communication performed by a first user equipment UE, the method comprising: Send a request message, the request message including information about a PC5 Quality of Service (QoS) flow for establishing a PC5 unicast link; Receive a response message from a second UE, the response message including corresponding information about the PC5 QoS flow for establishing the PC5 unicast link requested by the first UE; And Send data to the second UE via the PC5 unicast link by using a profile of the PC5 unicast link, wherein the information about the PC5 QoS flow includes a PC5 QoS Flow Identifier (PFI) and a PC5 5th Generation (5G) QoS Indicator (PQI), and wherein the profile includes at least one of a layer-2 identifier ID of the first UE, an application layer ID of the first UE, a layer-2 ID of the second UE, an application layer ID of the second UE, a PC5 5G QoS indicator PQI, or a PC5 QoS flow identifier PFI associated with the PQI.

2. The method according to claim 1, wherein, The layer-2 ID of the second UE is used for initial signaling for establishing the PC5 unicast link, and wherein a destination layer-2 ID of the request message is the layer-2 ID of the second UE.

3. The method according to claim 2, wherein, The destination layer-2 ID is the same or different for vehicle-to-everything (V2X) service types.

4. The method according to claim 1, wherein, The PFI is allocated in a V2X layer of the first UE, and wherein the V2X layer of the first UE provides at least one of data, a PFI, or a PQI to an access Application Service (AS) layer of the first UE.

5. The method according to claim 1, further comprising: Indicate whether the request message or the response message is for signaling from the V2X layer to the access AS layer.

6. The method according to claim 1, further comprising: Change at least one of the layer-2 ID of the first UE, the layer-2 ID of the second UE, the application layer ID of the first UE, or the application layer ID of the second UE.

7. The method according to claim 6, further comprising: Update the profile based on an update of a link layer identifier or a result of a change of at least one of the layer-2 ID of the first UE, the layer-2 ID of the second UE, the application layer ID of the first UE, or the application layer ID of the second UE.

8. A first user equipment UE for performing unicast communication, the first UE comprising: A transceiver; And At least one processor, coupled to the transceiver and configured to: Send a request message, the request message including information about a PC5 Quality of Service (QoS) flow for establishing a PC5 unicast link; Receive a response message from a second UE, the response message including corresponding information about the PC5 QoS flow for establishing the PC5 unicast link requested by the first UE; And Send data to the second UE via the PC5 unicast link by using a profile of the PC5 unicast link, wherein the information about the PC5 QoS flow includes a PC5 QoS Flow Identifier (PFI) and a PC5 5th Generation (5G) QoS Indicator (PQI), and wherein the profile includes at least one of a layer-2 identifier ID of the first UE, an application layer ID of the first UE, a layer-2 ID of the second UE, an application layer ID of the second UE, a PC5 5G QoS indicator PQI, or a PC5 QoS flow identifier PFI associated with the PQI.

9. The first UE according to claim 8, wherein, The layer-2 ID of the second UE is used to establish the initial signaling of the PC5 unicast link, and wherein, the destination layer-2 ID of the request message is the layer-2 ID of the second UE.

10. The first UE according to claim 9, wherein, The destination layer-2 ID is the same or different for the vehicle-to-everything V2X service type.

11. The first UE according to claim 8, wherein, The PFI is allocated in the vehicle-to-everything V2X layer of the first UE, and wherein, the V2X layer of the first UE provides at least one of data, PFI or PQI to the access AS layer of the first UE.

12. The first UE according to claim 8, wherein, The at least one processor is further configured to: indicate to the access AS layer from the vehicle-to-everything V2X layer whether the request message or the response message is for signaling.

13. The first UE according to claim 8, wherein, The at least one processor is further configured to: change at least one of the layer-2 ID of the first UE, the layer-2 ID of the second UE, the application layer ID of the first UE or the application layer ID of the second UE.

14. The first UE according to claim 13, wherein, The at least one processor is further configured to: update the profile based on the result of the update of the link layer identifier or the change of at least one of the layer-2 ID of the first UE, the layer-2 ID of the second UE, the application layer ID of the first UE or the application layer ID of the second UE.

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