Method and apparatus for modifying PDU sessions and always-on PDU sessions in a wireless communication system

Abstract

The present disclosure relates to a communication technology and a system thereof that combines a 5G communication system for supporting a higher data transmission rate than a 4G system with an IoT technology. The present disclosure can be applied to smart services (e.g., smart homes, smart buildings, smart cities, smart cars or connected cars, healthcare, digital education, retail business, security and safety related services, etc.) on the basis of 5G communication technology and IoT related technology. According to one embodiment of the present disclosure, a method performed by a session management function (SMF) entity in a communication system may include the following steps: performing a packet data unit (PDU) session establishment process; identifying a QoS flow generated for an ultra-reliable low-latency communication (URLLC) in a PDU session; identifying whether an indicator indicating that the PDU session is an always-online PDU session has been sent to a terminal; and when it is identified that the indicator has not been sent to a terminal, sending the indicator to the terminal.

Description

Technical Field

[0001] The present disclosure relates to content related to a communication system, and more particularly, to a method for managing a PDU session for a URLLC service. Background Art

[0002] In order to meet the increasing demand for wireless data traffic after the commercialization of the fourth generation (4G) communication system, efforts are being made to develop an enhanced 5G communication system [or pre-5G communication system]. For this reason, the 5G communication system [or pre-5G communication system] is called a super 4G network communication system or a post-LTE system.

[0003] In order to achieve high data transmission rates, 5G communication systems are being considered for implementation in millimeter wave bands (e.g., 60 gigahertz (60 GHz) bands). In order to reduce the path loss of radio waves in the millimeter wave band and increase the transmission distance of radio waves, beamforming, massive MIMO, full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and massive antenna technologies are being discussed in 5G communication systems.

[0004] In addition, in order to improve the network of the system, technologies such as improved small cells, advanced small cells, cloud radio access networks (cloud RAN), ultra-dense networks, device-to-device communication (D2D), wireless backhaul, mobile networks, cooperative communication, coordinated multi-point (CoMP), and reception interference cancellation are being developed in the 5G communication system.

[0005] In addition, hybrid FSK and QAM modulation (FQAM) and sliding window superposition coding (SWSC) as advanced coding modulation (ACM) schemes, and filter bank multi-carrier (FBMC), non-orthogonal multiple access (NOMA) and sparse code multiple access (SCMA) as advanced access technologies are being developed in 5G systems.

[0006] In addition, in the 5G system, support for various services compared to the existing 4G system is considered. For example, the most representative services may include enhanced mobile broadband (eMBB), ultra-reliable low-latency communication (URLLC), massive machine type communication (mMTC), evolved multimedia broadcast / multicast service (eMBMS), etc. In addition, a system that provides URLLC services may be referred to as a URLLC system, a system that provides eMBB services may be referred to as an eMBB system, etc. In addition, the terms referred to as services and systems may be used interchangeably.

[0007] The URLLC service is a newly considered service in the 5G system that is different from the existing 4G system, and compared with other services, it is necessary to meet ultra-reliability (e.g., a packet error rate of about 10 to 5) and low latency (e.g., about 0.5 milliseconds) conditions. In order to meet such strict requirements, it may be necessary to apply a shorter transmission time interval (TTI) than the eMBB service to the URLLC service. Various operating methods using short TTI are considered.

[0008] At the same time, the Internet has evolved from a human-centric connection network through which humans generate and consume information to the Internet of Things (IoT), through which information is exchanged and processed between distributed elements (such as things). Internet of Everything (IoE) technology is emerging, in which big data processing technology is combined with IoT technology through connection with cloud servers. In order to realize IoT, technical elements such as sensing technology, wired / wireless communication and network infrastructure, service interface technology, and security technology are required. Therefore, technologies for connection between things, such as sensor networks, machine-to-machine (M2M), and machine type communication (MTC), are being studied recently.

[0009] In the IoT environment, intelligent Internet technology (IT) services can be provided, in which new value is created for human life by collecting and analyzing data generated from connected things. Through the integration and combination between existing information technology (IT) and various industries, IoT can be applied to fields such as smart homes, smart buildings, smart cities, smart cars or connected cars, smart grids, healthcare, smart appliances, and advanced medical services.

[0010] Therefore, various attempts are being made to apply 5G communication systems to IoT. For example, technologies such as sensor networks, machine-to-machine (M2M), and machine-type communications (MTC) are implemented through schemes such as beamforming, MIMO, and array antennas (i.e., 5G communication technologies). Cloud radio access network (cloud RAN) as an application of the aforementioned big data processing technology can be said to be an example of the fusion between 5G technology and IoT technology.

[0011] Since various services may be provided according to the above contents and the development of mobile communication systems, in particular, a scheme for effectively using a non-public network (NPN) is required. Summary of the invention

[0012] Technical issues

[0013] The disclosed embodiments will provide a method and apparatus capable of effectively providing services in a wireless communication system.

[0014] Technical Solution

[0015] According to an embodiment of the present disclosure, a method for a session management function (SMF) entity in a communication system for achieving the aforementioned purpose may include: executing a packet data unit (PDU) session establishment process; identifying a QoS flow generated for ultra-reliable low-latency communication (URLLC) in the PDU session; identifying whether an indicator indicating that the PDU session is an always-online PDU session has been sent to a user equipment (UE); and based on the indicator being identified as not having been sent to the UE, sending the indicator to the UE.

[0016] According to an embodiment, identifying whether an indicator indicating that the PDU session is an always-on PDU session has been sent to a user equipment (UE) may include identifying whether the indicator has been sent to the UE in a PDU session establishment procedure or a PDU session modification procedure.

[0017] According to an embodiment, the indicator may be sent to the UE through a PDU session modification procedure.

[0018] According to an embodiment, user plane resources for an always-on PDU session may be established whenever the UE transitions from a connection management (CM)-IDLE mode to a CM-CONNECTED mode.

[0019] In addition, a method of a terminal in a communication system according to an embodiment of the present disclosure may include: performing a packet data unit (PDU) session establishment process; identifying a QoS flow generated for an ultra-reliable low-latency communication (URLLC) in the PDU session; and receiving an indicator from a session management function (SMF) based on not having received an indicator from the SMF indicating that the PDU session is an always-online PDU session.

[0020] In addition, a session management function (SMF) entity in a communication system according to an embodiment of the present disclosure may include a transceiver unit and a controller, wherein the controller is configured to perform a packet data unit (PDU) session establishment process, identify a QoS flow generated for ultra-reliable low-latency communication (URLLC) in the PDU session, identify whether an indicator indicating that the PDU session is an always-online PDU session has been sent to a user equipment (UE), and based on the indicator being identified as not having been sent to the UE, send the indicator to the UE.

[0021] In addition, a terminal in a communication system according to an embodiment of the present disclosure may include a transceiver unit and a controller, wherein the controller is configured to perform a packet data unit (PDU) session establishment process, identify a QoS flow generated for ultra-reliable low-latency communication (URLLC) in the PDU session, and receive an indicator from a session management function (SMF) based on not having received an indicator from the SMF indicating that the PDU session is an always-online PDU session.

[0022] Advantageous Effects of the Invention

[0023] The disclosed embodiments provide an apparatus and method capable of effectively providing services in a wireless communication system. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a diagram showing the structure of a 5G network according to an embodiment of the present disclosure.

[0025] Figures 2AA to 2AB is a diagram illustrating a PDU session modification procedure according to an embodiment of the present disclosure.

[0026] Figure 2BA to 2BB is a diagram illustrating a PDU session establishment process according to an embodiment of the present disclosure.

[0027] Figure 3 is a diagram illustrating the operation of the SMF when a new QoS flow appears according to an embodiment of the present disclosure.

[0028] Figure 4 is a diagram illustrating the operation of the SMF when a QoS flow is released according to an embodiment of the present disclosure.

[0029] Figure 5 is a diagram illustrating an operation of a UE when a new QoS flow appears according to an embodiment of the present disclosure.

[0030] Figure 6 is a diagram illustrating an operation of a UE when a QoS flow is released according to an embodiment of the present disclosure.

[0031] Figure 7 is a diagram showing a structure of a terminal according to an embodiment of the present disclosure.

[0032] Figure 8 is a diagram showing a structure of a network entity device according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0033] Hereinafter, preferred embodiments of the present disclosure are described in detail with reference to the accompanying drawings. It should be noted that in the accompanying drawings, the same reference numerals are used to refer to the same elements. In addition, detailed descriptions of known functions or structures that may obscure the subject matter of the present disclosure will be omitted.

[0034] In this specification, when describing the embodiments, descriptions of technical contents that are well known in the art to which the present disclosure belongs and are not directly related to the present disclosure are omitted, so as to clearly convey the subject matter of the present disclosure without obscuring the subject matter of the present disclosure due to omitting unnecessary descriptions.

[0035] For the same reason, in the accompanying drawings, some elements are enlarged, omitted or schematically depicted. In addition, the size of each element cannot accurately reflect its actual size. In the accompanying drawings, the same or similar elements are given the same reference numerals.

[0036] The advantages and features of the present disclosure and the methods for achieving these advantages and features will become apparent from the embodiments described in detail in conjunction with the accompanying drawings. However, the present disclosure is not limited to the disclosed embodiments, but can be implemented in various different forms. The embodiments are provided only to complete the present disclosure and to fully inform the category of the present disclosure to those of ordinary skill in the art to which the present disclosure belongs. The present disclosure is defined by the category of the claims. Throughout the specification, the same reference numerals represent the same components.

[0037] In the present disclosure, it will be understood that each box of the flowchart illustration and the combination of boxes in the flowchart illustration can be performed by computer program instructions. These computer program instructions can be installed on a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, so that the instructions executed by the processor of the computer or other programmable data processing device create a device for performing the functions specified in the (multiple) flowchart blocks. These computer program instructions can also be stored in a computer-usable or computer-readable storage memory, which can instruct the computer or other programmable data processing device to implement the functions in a specific manner, so that the instructions stored in the computer-usable or computer-readable memory produce a product including an instruction device that implements the functions specified in the (multiple) flowchart blocks. The computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are performed on the computer or other programmable data processing device, thereby generating a computer-executed process, so that the instructions of the executing computer or other programmable data processing device provide steps for performing the functions described in the (multiple) flowchart blocks.

[0038] In addition, each box of the flow chart may represent a part of a module, segment or code, which includes one or more executable instructions for implementing (multiple) specific logical functions. It should also be noted that in some alternative embodiments, the functions mentioned in the box may not appear in order. For example, two boxes shown in succession can actually be executed substantially simultaneously, or these boxes can sometimes be executed in reverse order, depending on the functions involved.

[0039] In this case, the term "unit" used in the present embodiment means a software or hardware component, such as a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC), and the "unit" performs a specific task. However, the term "-unit" does not mean that it is limited to software or hardware. "Unit" can be advantageously configured to reside on an addressable storage medium, and is configured to operate on one or more processors. Therefore, "unit" can include, for example, components, such as software components, object-oriented software components, class components and task components, processes, functions, attributes, procedures, subroutines, program code segments, drivers, firmware, microcodes, circuits, data, databases, data structures, tables, arrays and variables. The functions provided in components and "units" can be combined into fewer components and "units", or can be further divided into additional components and "units". In addition, components and "units" can be implemented as operating on one or more CPUs in a device or a secure multimedia card.

[0040] In the following, a base station is an object that allocates resources to a terminal, and may be at least one of a node B, a base station (BS), an eNode B (eNB), a gNode B (gNB), a wireless access unit, a base station controller, or a node in a network. The terminal may include a user equipment (UE), a mobile station (MS), a cellular phone, a smart phone, a computer, or a multimedia system capable of performing a communication function. In addition, the embodiments of the present disclosure may also be applied to other communication systems having a technical background or channel form similar to the embodiments of the present disclosure described below. In addition, based on the decision of a person with skilled technical knowledge, the embodiments of the present disclosure may also be applied to other communication systems by some modifications within the scope of not deviating too much from the scope of the present disclosure.

[0041] For the convenience of description, in the following description, terms for identifying access nodes, terms indicating network entities or network functions (NFs), terms indicating messages, terms indicating interfaces between network entities, terms indicating various types of identification information, etc. are used. Therefore, the present disclosure is not limited to the terms described later, and another term indicating an object having an equivalent technical meaning may be used.

[0042] Hereinafter, for convenience of description, some terms and names defined in the 3rd Generation Partnership Project Long Term Evolution (3GPP LTE) standard may be used. However, the present disclosure is not limited by the terms and names and may also be similarly applied to systems complying with other standards.

[0043] An embodiment of the present disclosure provides a method that is capable of modifying a PDU session configured for an ultra-reliable low-latency communication (URLLC) service to an always-on PDU session, or modifying an always-on PDU session to a PDU session, based on the presence or absence of an ultra-reliable low-latency communication (URLLC) service.

[0044] Figure 1 : is a diagram showing the structure of a 5G network according to an embodiment of the present disclosure. The network entities or network nodes constituting the 5G network are described as follows.

[0045] The (radio) access network ((R)AN)) is a subject that performs the allocation of radio resources to the terminal, and may be at least one of an eNode B, a Node B, a base station (BS), a next generation radio access network (NG-RAN), a 5G-AN, a wireless access unit, a base station controller, or a node in the network. The terminal may include a user equipment (UE), a next generation UE (NG UE), a mobile station (MS), a cellular phone, a smart phone, a computer, or a multimedia system capable of performing a communication function. In addition, in the following, the embodiments of the present disclosure are described as examples of 5G systems, but the embodiments of the present disclosure may also be applied to other communication systems with similar technical backgrounds. In addition, based on the decision of a person with skilled technical knowledge, the embodiments of the present disclosure may also be applied to other communication systems by some modifications within the scope that does not deviate too much from the scope of the present disclosure.

[0046] As the 4G system evolves to the 5G system, the wireless communication system defines the next generation core (NG core), that is, the new core network, or the 5G core network (5GC). The new core network generates all existing network entities (NEs) as network functions (NFs) by virtualizing network entities. According to an embodiment of the present disclosure, a network function may refer to a network entity, a network component, or a network resource.

[0047] According to an embodiment of the present disclosure, 5GC may include Figure 1 The present disclosure is not limited to Figure 1 An example of , and 5GC may include Figure 1 The NF shown is more or less NF.

[0048] According to an embodiment of the present disclosure, an access and mobility management function (AMF) may be a network function for managing the mobility of a UE.

[0049] According to an embodiment of the present disclosure, a session management function (SMF) may be a network function for managing a packet data network (PDN) connection provided to a UE. The PDN connection may be expressed as a name of a protocol data unit (PDU) session.

[0050] According to an embodiment of the present disclosure, a policy control function (PCF) may be a network function that applies a service policy, a charging policy, and a policy for a PDU session of a mobile communication operator to a UE.

[0051] According to an embodiment of the present disclosure, unified data management (UDM) may be a network function that stores information about a user.

[0052] According to an embodiment of the present disclosure, the network exposure function (NEF) may be a function of providing information about the UE to a server outside the 5G network. In addition, the NEF may provide a function for storing information required for services in the 5G network in the UDR by providing the information.

[0053] According to an embodiment of the present disclosure, a user plane function (UPF) may be a function for performing a gateway role for transmitting user data (PDU) to a data network (DN).

[0054] According to an embodiment of the present disclosure, a network repository function (NRF) may perform a function for discovering a NF.

[0055] According to an embodiment of the present disclosure, an authentication server function (AUSF) may perform UE authentication in a 3GPP access network and a non-3GPP access network.

[0056] According to an embodiment of the present disclosure, a network slice selection function (NSSF) may perform a function for selecting a network slice instance provided to a UE.

[0057] According to an embodiment of the present disclosure, a data network (DN) may be a data network through which a UE transmits and receives data in order to use a service of a network operator or a third-party service.

[0058] Figures 2AA to 2AB is a diagram illustrating a PDU session modification procedure according to an embodiment of the present disclosure.

[0059] Steps 1a to 1f illustrate the events performed by the UE, base station or network function during the PDU session modification process. In step 1a, the UE may start the modification of the PDU session by transmitting a PDU session modification request message to the SMF via the AMF. The PDU session modification request message may include parameters such as PDU session ID, packet filter, operation, requested QoS, isolation, 5GSM core network capability, number of packet filters, [always-online PDU session request indication], [always-online PDU session release request indication], etc.

[0060] To request QoS treatment for a specific service data flow (SDF), the UE may include in a PDU Session Modification Request message operations related to being able to specify the SDF, requested QoS, and isolated packet filters.

[0061] In addition, when performing a handover of a PDU session established in an Evolved Packet System (EPS) from EPS to 5GS, the UE may include an always-online PDU session request indication in a PDU session modification request message so as to modify the PDU session to an always-online PDU session. In addition, when a new URLLC service is started and a URLLC QoS flow is sent by using an existing PDU session, the UE may include an always-online PDU session request indication in a PDU session modification request message so as to modify the existing PDU session to an always-online PDU session. Conversely, when the corresponding PDU session no longer needs to be maintained as an always-online PDU session because the service using the existing URLLC QoS flow is terminated relative to a specific PDU session, the UE may include an always-online PDU session release request indication in the PDU session modification request message. When modifying an always-online PDU session to a PDU session, the UE may identify whether the corresponding PDU session has been established as an always-online PDU session for another reason other than reliable transmission. If the corresponding PDU session has been established as an always-online PDU session for another reason, the SMF will not modify the always-online PDU session to a PDU session. Hereinafter, in this specification, "PDU session" may be interpreted as meaning a normal PDU session rather than an always-online PDU session, but may be interpreted as including an always-online PDU session and a PDU session that is not an always-online PDU session, depending on the context.

[0062] At the same time, based on the presence or absence of a NAS signaling connection (N1 connection) with the AMF, the UE can be in a connection management-IDLE (CM-IDLE) or connection management-CONNECTED (CM-CONNECTED) state. In this case, the UE needs to be in the CM-CONNECTED state in order to send user data and control signals to the base station or network and receive user data and control signals from the base station or network.

[0063] When the UE transitions from the CM-IDLE state to the CM-CONNECTED state, in the case of an always-online PDU session, the user plane (UP) connection is always activated. In addition, typically, the SMF deactivates the UP connection if data has not been transmitted in the PDU session for a period of time, but the deactivation is not applied to the always-online PDU session. That is, in the case of an always-online PDU session, the UP connection is always activated when the UE is in the CM-CONNECTED state. When providing URLLC services that are very sensitive to delay, the service may fail due to the UP connection configuration time. Therefore, it is very important to establish the PDU session that sends the URLLC QoS flow as an always-online PDU session.

[0064] As a footnote to the CM-IDLE state and the CM-CONNECTED state, the UE in the CM-IDLE state does not have a NAS signaling connection (N1 connection) with the AMF. In this case, not only the AN signaling connection with the NG-RAN, but also the N2 connection and N3 connection of the corresponding UE may not exist. That is, the UE in the CM-IDLE state cannot exchange user data or control signals through the uplink (UL) or downlink (DL). When user data or control signals toward the UE appear, the network transitions to the CM-CONNECTED state through a service request process (paging process) triggered by the network. Conversely, when user data or control signals to be sent from the UE to the network appear, the UE transitions to the CM-CONNECTED state through a service request process. In the CM-CONNECTED state, the UE has a NAS signaling connection (N1) with the AMF.

[0065] However, although there is no data to be transmitted, the UP connection for the always-online PDU session is always activated. Therefore, the NG-RAN and UPF need to always allocate resources for the always-online PDU session, and unnecessary signaling may occur. For this reason, when the always-online PDU session does not need to be used, the always-online PDU session is preferably modified to a PDU session.

[0066] Steps 1b, 1c and 1d show PDU session modification requested by the SMF. PDU session modification can occur when policy is changed by the PCF, when subscription data is changed by the UDM, or when a modification request is received by a configuration policy within the SMF or from the (R)AN.

[0067] Steps 1e and 1f show the case where PDU session modification is requested by requests from AN and AMF respectively.

[0068] In steps 2a and 2b, the SMF can determine whether to use redundant transmission to perform reliable transmission for a specific QoS flow based on the authorized 5QI, NG-RAN node capabilities and operator configuration information. That is, the SMF can determine whether a specific QoS flow is used for URLLC service. If the SMF determines that a specific QoS flow is a QoS flow for URLLC service, the SMF can allocate additional CN tunnel information and send the additional CN tunnel information to the UPF, thereby configuring two GTP-U tunnels between the NG-RAN and the UPF. In addition, in order to perform redundant transmission of packets transmitted through the corresponding QoS flow using two GTP-U tunnels, the SMF instructs the UPF to perform packet duplication (in the case of DL) and packet elimination (in the case of UL). If the UPF allocates additional CN tunnel information, the UPF can allocate the additional CN tunnel information and can notify the SMF of the additional CN tunnel information.

[0069] Conversely, the SMF can determine whether to stop reliable transmission of the QoS flow for the existing URLLC service. The SMF can determine whether to stop reliable transmission based on the authorized 5QI, NG-RAN node capabilities, and operator configuration information, or if the corresponding QoS flow is no longer transmitted, it can determine to stop reliable transmission. At this time, the SMF can instruct the UPF to release the additional CN tunnel information allocated to it and stop the packet copy (in the case of DL) operation and packet elimination (in the case of UL) operation for redundant transmission.

[0070] The SMF can configure two intermediate UPFs (I-UPFs) between the NG-RAN and the PDU Session Anchor (PSA) UPF and perform redundant transmission. To this end, the SMF allocates the two I-UPFs, sends the UL CN tunnel information of the two I-UPFs to the PSAUPF, and sends the DL CN tunnel information of the PSAUPF to the I-UPF. The PSA UPF request for redundant transmission and redundant transmission release is the same as described above.

[0071] In step 3a, when the UE or AN requests modification, the SMF may respond to the request with the N2 SM Information (AN) encapsulated in a Nsmf_PDU Session_UpdateSMContext response message or a PDU Session Modification Command (UE) message.

[0072] The PDU Session Modify Command message may include parameters such as PDU Session ID, QoS Rule(s), QoS Rule Operation, QoS Flow Level, QoS Parameters, Session-AMBR, [Always-Online PDU Session Grant Indication], and [Always-Online PDU Session Release Grant Indication].

[0073] The always-online PDU session grant indication is a parameter sent by the SMF as a response when the UE requests to modify a specific PDU session to an always-online PDU session. Alternatively, although the UE has not sent the always-online PDU session request indication (that is, although the UE has not requested to modify the specific PDU session to an always-online PDU session), if the SMF has determined in step 2a to perform reliable transmission for a specific QoS flow, the SMF can notify the UE that the corresponding PDU session has been modified to an always-online PDU session by including the always-online PDU session grant indication in the PDU session modification command message. The reason is that when the UE transitions from the CM-IDLE state to the CM-CONNECTED state, the UE must request UP connection activation for the corresponding PDU session. That is, the UE that has received the always-online PDU session grant indication can include the ID of the corresponding PDU session in the parameter "PDU session list to be activated" in a process such as registration or service request.

[0074] The always-online PDU session release grant indication is a parameter sent by the SMF as a response when the UE requests to modify the always-online PDU session to a PDU session. Alternatively, although the UE has not sent the always-online PDU session release request indication (i.e., although the UE has not requested to modify the always-online PDU session to a PDU session), if the SMF has determined in step 2a to stop the reliable transmission for a specific QoS flow, the SMF can notify the UE that the always-online PDU session has been modified to a PDU session by including the always-online PDU session release grant indication in the PDU session modification command message. The reason for this is that it is necessary to notify the UE that the always-online PDU session has been modified to a PDU session in order to stop the request for UP connection activation of the corresponding PDU session, because when the UE transitions from the CM-IDLE state to the CM-CONNECTED state, if the corresponding PDU session is still configured as an always-online PDU session, the UE will request UP connection activation. That is, the UE that has received the always-online PDU session release grant indication can stop including the ID of the corresponding PDU session in the "PDU session list to be activated" parameter in a process such as registration or service request. When modifying an always-online PDU session to a PDU session without a request from the UE, the SMF can identify whether the corresponding PDU session has been established as an always-online PDU session for another reason other than reliable transmission. If the corresponding PDU session has been established as an always-online PDU session for another reason, the SMF will not modify the always-online PDU session to a PDU session.

[0075] If the SMF has determined in step 2a to perform reliable transmission, the CN tunnel information for the additional tunnel may be included in the N2 SM information. In addition, the SMF instructs the NG-RAN to use two GTP-U tunnels to perform packet duplication (in the case of UL) and packet elimination (in the case of DL) for redundant transmission for packets transmitted through the corresponding QoS flow.

[0076] Conversely, the SMF can determine whether to stop reliable transmission of the QoS flow for the existing URLLC service. The SMF can determine whether to stop reliable transmission based on the authorized 5QI, NG-RAN node capabilities, and operator configuration information, or if the corresponding QoS flow is no longer transmitted, it can determine to stop reliable transmission. At this time, the SMF can instruct the NG-RAN to release the additional AN tunnel information and stop the packet duplication (in the case of UL) and packet elimination (in the case of DL) operations for redundant transmission.

[0077] When modification is requested in step 3b, the SMF transmits the modified content according to the modification of the N2 SM information (AN) encapsulated in a Namf_Communication_N1N2MessageTransfer message or a PDU Session Modification Command (UE) message.

[0078] The PDU Session Modify Command message may include parameters such as PDU Session ID, QoS Rule(s), QoS Rule Operation, QoS Flow Level, QoS Parameters, Session-AMBR, [Always-Online PDU Session Grant Indication], and [Always-Online PDU Session Release Grant Indication].

[0079] If the SMF determines in step 2a that reliable transmission for a specific QoS flow is performed, the always-online PDU session grant indication is a parameter sent from the SMF to the UE. In this case, the SMF can notify the UE that the corresponding PDU session has been modified to an always-online PDU session by including the always-online PDU session grant indication in the PDU session modification command message. The reason is that when the UE transitions from the CM-IDLE state to the CM-CONNECTED state, the UE must request UP connection activation for the corresponding PDU session. That is, the UE that has received the always-online PDU session grant indication can include the ID of the corresponding PDU session in the "PDU session list to be activated" parameter in a process such as registration or service request.

[0080] If the SMF has determined in step 2a to stop reliable transmission for a specific QoS flow, the always-online PDU session release grant indication is a parameter sent from the SMF to the UE. In this case, the SMF can notify the UE that the always-online PDU session has been modified to a PDU session by including the always-online PDU session release grant indication in the PDU session modification command message. The reason is that it is necessary to notify the UE that the always-online PDU session has been modified to a PDU session in order to stop the request for UP connection activation of the corresponding PDU session, because when the UE transitions from the CM-IDLE state to the CM-CONNECTED state, if the corresponding PDU session is still configured as an always-online PDU session, the UE will request UP connection activation. That is, the UE that has received the always-online PDU session release grant indication can stop including the ID of the corresponding PDU session in the "PDU session list to be activated" parameter in a process such as registration or service request. When the always-online PDU session is modified to a PDU session without a request from the UE, the SMF can identify whether the corresponding PDU session is established as an always-online PDU session due to another reason other than reliable transmission. If the corresponding PDU session has already been established as an always-online PDU session for another reason, the SMF will not modify the always-online PDU session to a PDU session.

[0081] If the SMF has determined in step 2a to perform reliable transmission, the CN tunnel information for the additional tunnel may be included in the N2 SM information. In addition, the SMF instructs the NG-RAN to use two GTP-U tunnels to perform packet duplication (in the case of UL) and packet elimination (in the case of DL) for redundant transmission for packets transmitted through the corresponding QoS flow.

[0082] Conversely, the SMF can determine whether to stop reliable transmission of the QoS flow for the existing URLLC service. The SMF can determine whether to stop reliable transmission based on the authorized 5QI, NG-RAN node capabilities, and operator configuration information, or if the corresponding QoS flow is no longer transmitted, it can determine to stop reliable transmission. At this time, the SMF can instruct the NG-RAN to release the additional AN tunnel information and stop the packet duplication (in the case of UL) and packet elimination (in the case of DL) operations for redundant transmission.

[0083] If in step 3c the SMF requests modification due to an update of SMF related parameters from the UDM, the SMF may send relevant information to the AMF.

[0084] Through steps 4 and 5, the N1 SM container encapsulating the N2 SM information and the PDU session modification command can be sent to the NG-RAN and the UE.

[0085] In step 6, the NG-RAN may allocate additional AN tunnel information for reliable transmission, and may send the additional AN tunnel information to the AMF via N2SM information (in step 2a, if the SMF has determined to perform reliable transmission).

[0086] In steps 7a and 7b, the AMF may transmit N2 SM information to the SMF.

[0087] In steps 8a and 8b, the SMF may transmit the additional AN tunnel information for reliable transmission received from the NG-RAN to the UPF or I-UPF. If the CN tunnel information of the I-UPF has been specified in the UPF in step 2b, the SMF may transmit the DL CN tunnel information of the two I-UPFs to the PSA UPF.

[0088] In steps 9 to 11b, the UE may send an acknowledgement of the PDU Session Modification Command message. The NG-RAN and AMF may transmit the PDU Session Modification Command message to the SMF.

[0089] In step 12, the SMF may update the N4 session with the UPF.

[0090] In step 13, the SMF may inform the PCF of the result as to whether the PCC decision has been incorporated.

[0091] Figure 2BA to 2BB is a diagram illustrating a PDU session establishment process according to an embodiment of the present disclosure.

[0092] In step 1, the UE may encapsulate a PDU session establishment request message in a NAS message and transmit the PDU session establishment request message to the SMF via the AMF to establish a PDU session. If the UE attempts to establish a PDU session supporting a URLLC QoS flow, the UE may request an always-online PDU session establishment by including an always-online PDU session request indication in the PDU session establishment request message.

[0093] In step 11, the SMF may send a PDU session establishment acceptance message to be sent to the UE to the AMF by encapsulating the PDU session establishment acceptance message in a Namf_Communication_N1N2MessageTransfer message. If the UE requests the establishment of an always-online PDU session by including an always-online PDU session request indication in a PDU session establishment request message, the SMF may respond to the request through a PDU session establishment acceptance message. If the SMF allows the establishment, the SMF may include an always-online PDU session permission indication in the PDU session establishment acceptance message. Alternatively, although the UE does not send an always-online PDU session request indication through a PDU session establishment request message, if the SMF has determined that an always-online PDU session is required, the SMF may include an always-online PDU session permission indication in the PDU session establishment acceptance message. If in step 10a, the SMF has determined to perform reliable transmission for a specific QoS flow, the SMF may include an always-online PDU session permission indication in the PDU session establishment acceptance message. Therefore, the UE may be notified that the corresponding PDU session has been established as an always-online PDU session. The reason is that when the UE transitions from the CM-IDLE state to the CM-CONNECTED state, the UE must request UP connection activation for the corresponding PDU session. That is, the UE that has received the Always-On PDU Session Grant indication can include the ID of the corresponding PDU session in the "PDU Session List to be Activated" parameter in a process such as registration or service request.

[0094] Figure 3 is a diagram showing the operation of the SMF when a new QoS flow appears according to an embodiment of the present disclosure. In the following, as an example, Figure 3 Each of the steps disclosed in will be described as being performed autonomously by the SMF. Each step can be implemented according to any embodiment, which can be implemented by a person of ordinary skill in the art to which the present disclosure belongs without limiting the scope of the present disclosure, and can be performed by any component included in a manner capable of performing each step in response to, for example, a request from the SMF.

[0095] In step 301, when a QoS flow appears, the SMF can determine whether the new QoS flow is a URLLC service.

[0096] In step 302, the SMF may determine whether the existing QoS flow associated with the PDU session of the corresponding QoS flow other than the new QoS flow in step 301 is a service for the URLLC service through information such as the authorized 5QI, the NG-RAN node capability, and the operator configuration. In addition, the SMF may determine whether to perform reliable transmission based on the result of the determination. That is, if the new QoS flow or the existing QoS flow is a service for the URLLC service, the SMF may determine to perform reliable transmission, and if the new QoS flow or the existing QoS flow is not a service for the URLLC service, it may be determined not to perform reliable transmission.

[0097] If the SMF has determined in step 302 not to perform reliable transmission, then in step 303 the SMF may not include an always-online PDU session grant indication in the PDU session modification command message.

[0098] If the SMF has determined to perform reliable transmission in step 302, then in step 304, the SMF may determine whether the PDU session in which the corresponding QoS flow is now transmitted is an always-online PDU session. For example, the SMF may determine whether the PDU session in which the corresponding QoS flow is now transmitted is an always-online PDU session based on whether an always-online PDU session permission indication has been transmitted to the UE through a previously executed PDU session establishment process or a PDU session modification process. That is, if the always-online PDU session permission indication has not been transmitted to the UE through a previously executed PDU session establishment process or a PDU session modification process, the SMF may determine that the PDU session in which the corresponding QoS flow is now transmitted is not an always-online PDU session.

[0099] If it is determined in step 304 that the PDU session in which the corresponding QoS flow is now transmitted is not an always-online PDU session, then in step 305, the SMF may include an always-online PDU session grant indication in the PDU session modification command message. The SMF may notify the UE that the corresponding PDU session has been modified to an always-online PDU session through the always-online PDU session grant indication parameter. The reason is that when the UE transitions from the CM-IDLE state to the CM-CONNECTED state, the UE must request UP connection activation for the corresponding PDU session. That is, the UE that has received the always-online PDU session grant indication may include the ID of the corresponding PDU session in the "PDU session list to be activated" parameter in a process such as registration or service request.

[0100] If it is determined in step 304 that the PDU session in which the corresponding QoS flow is currently transmitted is an always-online PDU session, then in step 306, the SMF may not include an always-online PDU session grant indication in the PDU session modification command message.

[0101] Figure 4 is a diagram showing the operation of the SMF when a QoS flow is released according to an embodiment of the present disclosure. In the following, as an example, Figure 4 Each of the steps disclosed in will be described as being performed autonomously by the SMF. Each step can be implemented according to any embodiment, which can be implemented by a person of ordinary skill in the art to which the present disclosure belongs without limiting the scope of the present disclosure, and can be performed by any component included in a manner capable of performing each step in response to, for example, a request from the SMF.

[0102] In step 401, when the corresponding QoS flow is released, the SMF can determine whether the QoS flow is used for URLLC service.

[0103] In step 402, the SMF can determine whether the QoS flow released in step 401 is used for URLLC service, and whether the existing QoS flow associated with the PDU session of the corresponding QoS flow no longer supports the URLLC service through information such as authorized 5QI, NG-RAN node capabilities, and operator configuration. In addition, the SMF can determine whether to perform reliable transmission based on the determined result. That is, if the released QoS flow or the existing QoS flow no longer supports the URLLC service, the SMF can determine not to perform reliable transmission, and if the released QoS flow or the existing QoS flow supports at least one URLLC service, it can be determined to perform reliable transmission.

[0104] If the QoS flow released in step 402 is not a QoS flow for the URLLC service, or if there is no change as to whether the existing QoS flow supports the URLLC service, that is, if at least one QoS flow still supports the URLLC service, then in step 403, the SMF may not include an always-online PDU session release grant indication in the PDU session modification command message.

[0105] If the QoS flow released in step 402 is a QoS flow for URLLC service, or the existing QoS flow does not support URLLC service, that is, if any QoS flow does not support URLLC service, then in step 404, the SMF can determine whether the current PDU session is established as an always-on PDU session due to other reasons besides URLLC service.

[0106] If in step 404 the current PDU session is not established as an always-online PDU session for reasons other than the URLLC service, then in step 405 the SMF may include an always-online PDU session release grant indication in the PDU session modification command message. The SMF may notify the UE that the always-online PDU session has been modified to a PDU session through the always-online PDU session release grant indication parameter. The reason for this is that the UE needs to be notified that the always-online PDU session has been modified to a PDU session in order to stop the request for UP connection activation of the corresponding PDU session, because when the UE transitions from the CM-IDLE state to the CM-CONNECTED state, if the corresponding PDU session is still configured as an always-online PDU session, the UE will request UP connection activation. That is, the UE that has received the always-online PDU session release grant indication may stop including the ID of the corresponding PDU session in the "PDU session list to be activated" parameter in a process such as a registration or service request.

[0107] If in step 404, the current PDU session is not established as an always-online PDU session for reasons other than URLLC service, then in step 406, the SMF may not include an always-online PDU session release grant indication in the PDU session modification command message.

[0108] Figure 5 is a diagram showing the operation of a UE when a new QoS flow appears according to an embodiment of the present disclosure. In the following, as an example, Figure 5 Each of the steps disclosed in the will be described as being performed autonomously by the UE. Each step can be implemented according to any embodiment, which can be implemented by a person of ordinary skill in the art to which the present disclosure belongs without limiting the scope of the present disclosure, and can be performed by any component included in a manner that can perform each step in response to a request from the UE, for example.

[0109] In step 501, when a QoS flow appears, the UE may determine whether the new QoS flow is for URLLC service.

[0110] In step 502, the UE may determine whether the new QoS flow and the existing QoS flow in step 501 are services for the URLLC service based on information received from a higher layer.

[0111] If it is determined in step 502 that the new QoS flow and the existing QoS flow are not QoS flows for URLLC services, then in step 503, the UE may not include an always-on PDU session request indication in the PDU session modification request message.

[0112] If it is determined in step 504 that the new QoS flow and the existing QoS flow in step 502 are QoS flows for URLLC service, the UE can determine whether the PDU session in which the corresponding QoS flow is now transmitted is an always-online PDU session. For example, the UE can determine whether the PDU session in which the corresponding QoS flow is now transmitted is an always-online PDU session based on whether an always-online PDU session permission indication has been received from the SMF through a previously performed PDU session establishment process or a PDU session modification process. That is, if an always-online PDU session permission indication is not received from the SMF through a previously performed PDU session establishment process or a PDU session modification process, the UE can determine that the PDU session in which the corresponding QoS flow is now transmitted is not an always-online PDU session.

[0113] If it is determined in step 504 that the PDU session in which the corresponding QoS flow is currently transmitted is not an always-on PDU session, then in step 505, the UE may include an always-on PDU session request indication in the PDU session modification request message.

[0114] If it is determined in step 504 that the PDU session in which the corresponding QoS flow is currently transmitted is an always-on PDU session, then in step 506, the UE may not include an always-on PDU session request indication in the PDU session modification request message.

[0115] Figure 6 is a diagram showing the operation of a UE when a QoS flow is released according to an embodiment of the present disclosure. In the following, as an example, Figure 6 Each of the steps disclosed in the will be described as being performed autonomously by the UE. Each step can be implemented according to any embodiment, which can be implemented by a person of ordinary skill in the art to which the present disclosure belongs without limiting the scope of the present disclosure, and can be performed by any component included in a manner that can perform each step in response to a request from the UE, for example.

[0116] In step 601, when the corresponding QoS flow is released, the UE may determine whether the QoS flow is used for URLLC service.

[0117] In step 602, the UE may determine whether existing QoS flows other than the QoS flow released in step 601 no longer support URLLC services through information received from a higher layer.

[0118] If the QoS flow released in step 602 is not a QoS flow for the URLLC service, or there is no change as to whether the existing QoS flow supports the URLLC service, that is, if at least one QoS flow still supports the URLLC service, then in step 603, the UE may not include an always-on PDU session release request indication in the PDU session modification request message.

[0119] If the QoS flow released in step 602 is a QoS flow for URLLC service, or the existing QoS flow does not support URLLC service, that is, if any QoS flow does not support URLLC service, then in step 604, the UE can determine whether the current PDU session is established as an always-on PDU session due to other reasons besides URLLC service.

[0120] If, in step 604, the current PDU session is not established as an always-on PDU session due to reasons other than the URLLC service, then in step 605, the UE may include an always-on PDU session release request indication in the PDU session modification request message.

[0121] If in step 604, the current PDU session has been established as an always-on PDU session due to reasons other than URLLC service, then in step 606, the UE may not include an always-on PDU session release request indication in the PDU session modification request message.

[0122] Figure 7 is a diagram showing the structure of a UE according to an embodiment of the present disclosure.

[0123] The UE according to an embodiment of the present disclosure may include a transceiver unit 720 and a controller 710 that controls the overall operation of the UE. In addition, the transceiver unit 720 may include a transmitter 723 and a receiver 726.

[0124] The transceiver unit 720 may transmit and receive signals to and from a base station or a network entity.

[0125] The controller 710 can control the UE to perform any one of the operations in the above embodiments. At the same time, the controller 710 and the transceiver unit 720 do not need to be implemented as separate modules in essence, and can be implemented as a component in the form of a single chip. In addition, the controller 710 and the transceiver unit 720 can be electrically connected. In addition, for example, the controller 710 can be a circuit, a dedicated circuit or at least one processor. In addition, the operation of the UE can be implemented by including a memory device storing a corresponding program code in any component in the UE.

[0126] Figure 8is a diagram showing a structure of a network entity according to an embodiment of the present disclosure.

[0127] The network entity according to an embodiment of the present disclosure may include a transceiver unit 820 and a controller 810 that controls the overall operation of the network entity. In addition, the transceiver unit 820 may include a transmitter 823 and a receiver 826.

[0128] The transceiver unit 820 may send signals to and receive signals from other network entities.

[0129] The controller 810 can control the network entity to perform any one of the operations in the above-mentioned embodiments. Meanwhile, the controller 810 and the transceiver unit 820 do not need to be implemented as separate modules in essence, and can be implemented as a component in the form of a single chip. In addition, the controller 810 and the transceiver unit 820 can be electrically connected. In addition, for example, the controller 810 can be a circuit, a dedicated circuit or at least one processor. In addition, the operation of the network entity can be implemented by including a memory device storing a corresponding program code in any component in the network entity.

[0130] It should be noted that Figures 7 and 8 The structural diagrams, example diagrams of the method of transmitting control / data signals, and example diagrams and structural diagrams of the operation process shown in the drawings are not intended to limit the scope of rights of the present disclosure. That is, all components, entities, or operation steps shown in the drawings should not be interpreted as necessary components for implementing the present disclosure, and can be implemented within the scope of not destroying the essence of the present disclosure, although only some components are included.

[0131] The above operations of the network entity, base station or terminal can be implemented by including a memory device storing corresponding program codes in any component within the network entity, base station or terminal device. That is, the controller of the network entity, base station or terminal device can perform the above operations by reading and executing the program codes stored in the memory device by a processor or a central processing unit (CPU).

[0132] The methods according to the embodiments written in the claims or the specification of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

[0133] If the method is implemented as software, a computer-readable storage medium storing one or more programs (software modules) may be provided. The one or more programs stored in the computer-readable storage medium are configured to be executable by one or more processors within an electronic device. The one or more programs include instructions that enable the electronic device to perform the method according to the embodiments, which are written in the claims or description of the present disclosure.

[0134] Such a program (software module or software) may be stored in a random access memory, a non-volatile memory including flash memory, a read-only memory (ROM), an electrically erasable programmable read-only memory (EEPROM), a magnetic disk storage device, a compact disk-ROM (CD-ROM), a digital versatile disk (DVD) or other type of optical storage device or a cassette tape. Alternatively, the program (software module or software) may be stored in a memory consisting of a combination of all or some of them. In addition, multiple configuration memories may be included.

[0135] In addition, the program can be stored in an attachable storage device that can be accessed through a communication network, such as the Internet, an intranet, a local area network (LAN), a wide area network (WLAN), or a storage area network (SAN), or a communication network composed of a combination thereof. Such a storage device can access the equipment that performs the embodiments of the present disclosure through an external port. In addition, a separate storage device in a communication network can access the equipment that performs the embodiments of the present disclosure.

[0136] In the above detailed embodiments of the present disclosure, the components included in the present disclosure have been expressed in singular or plural form, depending on the detailed embodiments proposed. However, the singular or plural expression has been appropriately selected for the situation proposed for the convenience of description, and the present disclosure is not limited to singular or plural components. Although the component has been expressed in plural form, it can also be configured in singular form. Although the component has been expressed in singular form, it can also be configured in plural form.

[0137] Although detailed embodiments have been described in the detailed description of the present disclosure, the present disclosure may be modified in various ways without departing from the scope of the present disclosure. Therefore, the scope of the present disclosure should not be limited to the above embodiments, but should be limited not only by the claims, but by their equivalents.

Claims

1. A method for a session management function (SMF) entity in a communication system, comprising: Execute a packet data unit PDU session establishment procedure or a first PDU session modification procedure; determining that an ultra-reliable low delay communication URLLC QoS flow established by a second PDU session modification procedure is created in the PDU session, wherein the URLLC QoS flow requires an always-on PDU session; and Based on determining that a URLLC QoS flow is generated in the PDU session, if an indicator indicating that the PDU session is an always-online PDU session is not sent to the UE during the PDU session establishment process or the first PDU session modification process, a PDU session modification command message for the second PDU session modification process is sent to the UE, wherein the PDU session modification command message includes the indicator.

2. The method according to claim 1, wherein: Whenever the UE transitions from connection management CM-IDLE mode to CM-CONNECTED mode, user plane resources for always-on PDU sessions are established.

3. A method for a user equipment UE in a communication system, comprising: Execute a packet data unit PDU session establishment procedure or a first PDU session modification procedure; as well as In a case where no indicator is received from the session management function SMF during the PDU session establishment process or the first PDU session modification process, a PDU session modification command message for a second PDU session modification process is received from the SMF, wherein the PDU session modification command message includes the indicator indicating that the PDU session is an always-online PDU session based on an ultra-reliable low-latency communication URLLC QoS flow created in the PDU session and established through the second PDU session modification process, wherein the URLLC QoS flow requires an always-online PDN session.

4. The method according to claim 3, wherein: Whenever the UE transitions from connection management CM-IDLE mode to CM-CONNECTED mode, user plane resources for always-on PDU sessions are established.

5. A session management function SMF entity in a communication system, comprising: transceiver unit; and The controller is configured as: Execute a packet data unit PDU session establishment procedure or a first PDU session modification procedure; determining that an ultra-reliable low delay communication URLLC QoS flow established by a second PDU session modification procedure is created in the PDU session, wherein the URLLC QoS flow requires an always-on PDU session, and Based on determining to create a URLLC QoS flow in the PDU session, if an indicator indicating that the PDU session is an always-online PDU session is not sent to the UE during the PDU session establishment process or the first PDU session modification process, a PDU session modification command message for the second PDU session modification process is sent to the UE, wherein the PDU session modification command message includes the indicator.

6. The SMF entity according to claim 5, wherein: Whenever the UE transitions from connection management CM-IDLE mode to CM-CONNECTED mode, user plane resources for always-on PDU sessions are established.

7. A user equipment UE in a communication system, comprising: transceiver unit; and The controller is configured as: performing a packet data unit (PDU) session establishment procedure or a first PDU session modification procedure, and In a case where no indicator is received from the session management function SMF during the PDU session establishment process or the first PDU session modification process, a PDU session modification command message for a second PDU session modification process is received from the SMF, wherein the PDU session modification command message includes the indicator indicating that the PDU session is an always-online PDU session based on an ultra-reliable low-latency communication URLLC QoS flow created in the PDU session and established through the second PDU session modification process, wherein the URLLC QoS flow requires an always-online PDN session.

8. The UE according to claim 7, wherein: Whenever the UE transitions from connection management CM-IDLE mode to CM-CONNECTED mode, user plane resources for always-on PDU sessions are established.

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