Apparatus and method for controlling network congestion in wireless communication system

Abstract

The objective of the present disclosure is to control network congestion in a wireless communication system, and this method performed by a network comprises the steps of: activating a congestion control function; receiving a request message from a terminal; and transmitting, to the terminal, a message including a rejection reason for the request message, wherein the rejection reason can indicate resource insufficiency for single network slice selection assistance information (LADN S-NSSAI) and a data network name (LADN DNN) within a local area data network (LADN) service area.

Description

Network congestion control device and method in a wireless communication system

[0001] The following description relates to a wireless communication system, and more particularly, to a device and method for controlling network congestion in a wireless communication system.

[0002] Wireless access systems are widely deployed to provide various types of communication services, such as voice and data. Typically, wireless access systems are multiple access systems that support communications with multiple users by sharing available system resources (e.g., bandwidth, transmission power). Examples of multiple access systems include code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), and single-carrier frequency division multiple access (SC-FDMA).

[0003] In particular, as numerous communication devices demand greater communication capacity, enhanced mobile broadband (eMBB) communication technologies are being proposed, improving upon existing radio access technology (RAT). Furthermore, massive machine type communications (mMTC), which connects numerous devices and objects to provide diverse services anytime and anywhere, as well as communication systems that consider reliability and latency-sensitive services / user equipment (UE), are being proposed. Various technological configurations are being proposed for these purposes.

[0004] The present disclosure relates to a device and method for controlling network congestion in a wireless communication system.

[0005] The present disclosure relates to a device and method for controlling overload and / or congestion of a group terminal in a wireless communication system.

[0006] The present disclosure relates to a device and method for controlling network congestion based on a local area data network (LDAN) service area in a wireless communication system.

[0007] The present disclosure relates to a device and method for indicating resource insufficiency for LADN S-NSSAI (single network slice selection assistance information) and LADN DNN (data network name) within an LDAN service area in a wireless communication system.

[0008] The present disclosure relates to a device and method for limiting network access of a group terminal based on a back-off timer in a wireless communication system.

[0009] The technical objectives to be achieved in the present disclosure are not limited to those mentioned above, and other technical tasks not mentioned can be considered by a person having ordinary skill in the technical field to which the technical configuration of the present disclosure is applied from the embodiments of the present disclosure described below.

[0010] As an example of the present disclosure, a method performed by a network in a wireless communication system includes the steps of activating a congestion control function, receiving a request message from a terminal, and transmitting a message including a reason for rejection of the request message to the terminal, wherein the reason for rejection may indicate insufficient resources for a local area data network (LADN) single network slice selection assistance information (LADN S-NSSAI) and a LADN data network name (DNN) within a LADN service area.

[0011] As an example of the present disclosure, a method performed by a terminal in a wireless communication system includes the steps of transmitting a request message to a network, receiving a message including a reason for rejection of the request message from the network, and controlling retransmission of the request message based on whether the message including the reason for rejection includes a backoff timer value, wherein the reason for rejection may indicate insufficient resources for a LADN S-NSSAI and a LADN DNN within a LADN service area.

[0012] As an example of the present disclosure, in a wireless communication system, a network device includes a transceiver and a processor connected to the transceiver, wherein the processor activates a congestion control function, receives a request message from a terminal, and controls transmission of a message including a reason for rejection of the request message to the terminal, wherein the reason for rejection may indicate insufficient resources for a LADN S-NSSAI and a LADN DNN within a LADN service area.

[0013] As an example of the present disclosure, in a wireless communication system, a terminal includes a transceiver and a processor connected to the transceiver, wherein the processor transmits a request message to a network, receives a message including a reason for rejection of the request message from the network, and controls retransmission of the request message based on whether a backoff timer value is included in the message including the reason for rejection, wherein the reason for rejection may indicate insufficient resources for a LADN S-NSSAI and a LADN DNN within a LADN service area.

[0014] As an example of the present disclosure, a communication device includes at least one processor, and at least one computer memory coupled to the at least one processor and storing instructions that, when executed by the at least one processor, direct operations, the operations including: transmitting a request message to a network; receiving a message from the network including a reason for rejection of the request message; and controlling retransmission of the request message based on whether the message including the reason for rejection includes a backoff timer value, wherein the reason for rejection may indicate insufficient resources for a LADN S-NSSAI and a LADN DNN within a LADN service area.

[0015] As an example of the present disclosure, a non-transitory computer-readable medium storing at least one instruction includes at least one instruction executable by a processor, the at least one instruction causing a device to transmit a request message to a network, receive a message from the network including a reason for rejection of the request message, and control retransmission of the request message based on whether the message including the reason for rejection includes a backoff timer value, wherein the reason for rejection may indicate insufficient resources for a LADN S-NSSAI and a LADN DNN within a LADN service area.

[0016] The following effects may be achieved by embodiments based on the present disclosure.

[0017] The present disclosure can perform overload and congestion control for group terminals in a wireless communication system.

[0018] The effects that can be obtained from the embodiments of the present disclosure are not limited to the effects mentioned above, and other effects that are not mentioned can be clearly derived and understood by those skilled in the art to which the technical configuration of the present disclosure is applied, from the description of the embodiments of the present disclosure below. In other words, unintended effects that result from implementing the configuration described in the present disclosure can also be derived by those skilled in the art from the embodiments of the present disclosure.

[0019] The accompanying drawings are intended to aid understanding of the present disclosure and, together with detailed descriptions, may provide embodiments of the present disclosure. However, the technical features of the present disclosure are not limited to specific drawings, and the features disclosed in each drawing may be combined with each other to form new embodiments. Reference numerals in each drawing may indicate structural elements.

[0020] Figure 1 illustrates an example of a communication system applicable to the present disclosure.

[0021] FIG. 2 illustrates an example of a user equipment (UE) applicable to the present disclosure.

[0022] FIG. 3 illustrates an example of functional separation of a next generation radio access network (NG-RAN) and a 5th generation core (5GC) applicable to the present disclosure.

[0023] FIG. 4 illustrates an example of a general architecture of a 5G (5th generation) system applicable to the present disclosure.

[0024] FIG. 5 illustrates an example of a congestion control procedure according to one embodiment of the present disclosure.

[0025] FIG. 6 illustrates an example of a congestion control procedure of AMF according to one embodiment of the present disclosure.

[0026] FIG. 7 illustrates an example of a congestion control procedure of an SMF according to one embodiment of the present disclosure.

[0027] FIG. 8 illustrates an example of a congestion control procedure of an SMF according to one embodiment of the present disclosure.

[0028] FIG. 9 illustrates an example of a request procedure of a terminal according to one embodiment of the present disclosure.

[0029] The following embodiments combine components and features of the present disclosure in a predetermined form. Each component or feature may be considered optional unless explicitly stated otherwise. Each component or feature may be implemented without being combined with other components or features. Furthermore, some components and / or features may be combined to form embodiments of the present disclosure. The order of operations described in the embodiments of the present disclosure may be changed. Some components or features of one embodiment may be included in another embodiment or may be replaced with corresponding components or features of another embodiment.

[0030] In the description of the drawings, procedures or steps that may obscure the gist of the present disclosure are not described, and procedures or steps that can be understood by a person skilled in the art are also not described.

[0031] Throughout the specification, when a part is said to "comprising" or "including" a component, this does not mean that other components may be included, but rather that other components may be excluded, unless otherwise specifically stated. In addition, terms such as "...part," "...unit," and "module" described in the specification mean a unit that processes at least one function or operation, which may be implemented by hardware, software, or a combination of hardware and software. In addition, the words "a" or "an," "one," "the," and similar related words may be used in the context of describing the present disclosure (especially in the context of the claims below) to include both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context.

[0032] Embodiments of the present disclosure described herein focus on the data transmission and reception relationship between a base station and a mobile station. Here, the base station is understood as a terminal node of a network that directly communicates with the mobile station. Certain operations described herein as being performed by the base station may, in some cases, be performed by an upper node of the base station.

[0033] That is, in a network consisting of multiple network nodes including a base station, various operations performed for communication with a mobile station may be performed by the base station or other network nodes other than the base station. In this case, the term 'base station' may be replaced by terms such as fixed station, Node B, eNB (eNode B), gNB (gNode B), ng-eNB, advanced base station (ABS), or access point.

[0034] Additionally, in embodiments of the present disclosure, the term terminal may be replaced with terms such as user equipment (UE), mobile station (MS), subscriber station (SS), mobile subscriber station (MSS), mobile terminal, or advanced mobile station (AMS).

[0035] Additionally, a transmitter refers to a fixed and / or mobile node that provides data or voice services, and a receiver refers to a fixed and / or mobile node that receives data or voice services. Therefore, for uplink, a mobile station can be the transmitter, and a base station can be the receiver. Similarly, for downlink, a mobile station can be the receiver, and a base station can be the transmitter.

[0036] Embodiments of the present disclosure are wireless access systems such as IEEE 802.xx system, 3rd Generation Partnership Project (3GPP) system, 3GPP Long Term Evolution (LTE) system, 3GPP 5G (5 th generation) NR (New Radio) system and 3GPP2 system, and in particular, embodiments of the present disclosure may be supported by 3GPP TS (technical specification) 38.211, 3GPP TS 38.212, 3GPP TS 38.213, 3GPP TS 38.321 and 3GPP TS 38.331 documents.

[0037] Furthermore, the embodiments of the present disclosure can be applied to other wireless access systems and are not limited to the aforementioned systems. For example, they can also be applied to systems implemented after the 3GPP 5G NR system, and are not limited to a specific system.

[0038] That is, obvious steps or parts not described in the embodiments of the present disclosure can be explained by referring to the above documents. In addition, all terms disclosed in this document can be explained by the above standard documents.

[0039] Hereinafter, preferred embodiments according to the present disclosure will be described in detail with reference to the accompanying drawings. The detailed description set forth below, together with the accompanying drawings, is intended to illustrate exemplary embodiments of the present disclosure and is not intended to represent the only embodiments in which the technical configurations of the present disclosure may be implemented.

[0040] Additionally, specific terms used in the embodiments of the present disclosure are provided to aid in understanding the present disclosure, and the use of such specific terms may be changed to other forms without departing from the technical spirit of the present disclosure.

[0041] The following technology can be applied to various wireless access systems such as CDMA (code division multiple access), FDMA (frequency division multiple access), TDMA (time division multiple access), OFDMA (orthogonal frequency division multiple access), and SC-FDMA (single carrier frequency division multiple access).

[0042] For clarity, the following description is based on a 3GPP communication system (e.g., LTE, NR, etc.), but the technical spirit of the present invention is not limited thereto. LTE may refer to technology after 3GPP TS 36.xxx Release 8. Specifically, LTE technology after 3GPP TS 36.xxx Release 10 may be referred to as LTE-A, and LTE technology after 3GPP TS 36.xxx Release 13 may be referred to as LTE-A pro. 3GPP NR may refer to technology after TS 38.xxx Release 15. 3GPP 6G may refer to technology after TS Release 17 and / or Release 18. "xxx" refers to a standard document detail number. LTE / NR / 6G may be collectively referred to as a 3GPP system.

[0043] For background information, terms, abbreviations, etc. used in this disclosure, reference may be made to standard documents published prior to the present invention. For example, reference may be made to the 36.xxx and 38.xxx standard documents.

[0044] For terms, abbreviations, and other background technology that may be used in this document, please refer to the standards documents published prior to this document. In particular, terms, abbreviations, and other background technology related to LTE / EPS (Evolved Packet System) can refer to the 36.xxx series, 23.xxx series, and 24.xxx series, and terms, abbreviations, and other background technology related to NR (new radio) / 5GS can refer to the 38.xxx series, 23.xxx series, and 24.xxx series.

[0045] Hereinafter, this specification is described based on the terms defined above.

[0046] The three key requirement areas for 5G include (1) Enhanced Mobile Broadband (eMBB), (2) Massive Machine Type Communication (mMTC), and (3) Ultra-reliable and Low Latency Communications (URLLC).

[0047] Some use cases may require optimization across multiple domains, while others may focus on just one Key Performance Indicator (KPI). 5G supports these diverse use cases in a flexible and reliable manner.

[0048] Communication system applicable to the present disclosure

[0049] Although not limited thereto, the various descriptions, functions, procedures, proposals, methods and / or operational flowcharts of the present disclosure disclosed in this document may be applied to various fields requiring wireless communication / connectivity (e.g., 5G) between devices.

[0050] Hereinafter, more specific examples will be provided with reference to the drawings. In the drawings / descriptions below, the same drawing reference numerals may represent identical or corresponding hardware blocks, software blocks, or functional blocks, unless otherwise described.

[0051] Figure 1 illustrates an example of a communication system applied to the present disclosure.

[0052] Referring to FIG. 1, a communication system (100) applied to the present disclosure includes a wireless device, a base station, and a network. Here, the wireless device refers to a device that performs communication using a wireless access technology (e.g., 5G NR, LTE) and may be referred to as a communication / wireless / 5G device. Although not limited thereto, the wireless device may include a robot (100a), a vehicle (100b-1, 100b-2), an XR (extended reality) device (100c), a hand-held device (100d), a home appliance (100e), an IoT (Internet of Things) device (100f), and an AI (artificial intelligence) device / server (100g). For example, the vehicle may include a vehicle equipped with a wireless communication function, an autonomous vehicle, a vehicle capable of performing vehicle-to-vehicle communication, etc. Here, the vehicles (100b-1, 100b-2) may include unmanned aerial vehicles (UAVs) (e.g., drones). The XR devices (100c) include augmented reality (AR) / virtual reality (VR) / mixed reality (MR) devices, and may be implemented in the form of head-mounted devices (HMDs), head-up displays (HUDs) installed in vehicles, televisions, smartphones, computers, wearable devices, home appliances, digital signage, vehicles, robots, etc. The portable devices (100d) may include smartphones, smart pads, wearable devices (e.g., smartwatches, smart glasses), computers (e.g., laptops, etc.), etc. The home appliances (100e) may include TVs, refrigerators, washing machines, etc. The IoT devices (100f) may include sensors, smart meters, etc. For example, the base station (120) and the network (130) may also be implemented as wireless devices, and a specific wireless device (120a) may act as a base station / network node to other wireless devices.

[0053] Wireless devices (100a to 100f) can be connected to a network (130) via a base station (120). AI technology can be applied to the wireless devices (100a to 100f), and the wireless devices (100a to 100f) can be connected to an AI server (100g) via a network (130). The network (130) can be configured using a 3G network, a 4G (e.g., LTE) network, a 5G (e.g., NR) network, etc. The wireless devices (100a to 100f) can communicate with each other via the base station (120) / network (130), but can also communicate directly (e.g., sidelink communication) without going through the base station (120) / network (130). For example, vehicles (100b-1, 100b-2) can communicate directly (e.g., V2V (vehicle to vehicle) / V2X (vehicle to everything) communication). In addition, IoT devices (100f) (e.g., sensors) can communicate directly with other IoT devices (e.g., sensors) or other wireless devices (100a to 100f).

[0054] Wireless communication / connection (150a, 150b, 150c) can be established between wireless devices (100a to 100f) / base stations (120), and base stations (120) / base stations (120). Here, the wireless communication / connection can be established through various wireless access technologies (e.g., 5G NR) such as uplink / downlink communication (150a), sidelink communication (150b) (or D2D communication), and base station-to-base station communication (150c) (e.g., relay, IAB (integrated access backhaul)). Through the wireless communication / connection (150a, 150b, 150c), the wireless device and base station / wireless device, and base stations and base stations can transmit / receive wireless signals to / from each other. For example, the wireless communication / connection (150a, 150b, 150c) can transmit / receive signals through various physical channels. To this end, based on various proposals of the present disclosure, at least some of various configuration information setting processes for transmitting / receiving wireless signals, various signal processing processes (e.g., channel encoding / decoding, modulation / demodulation, resource mapping / demapping, etc.), resource allocation processes, etc. may be performed.

[0055] Figure 2 illustrates an example of a UE applicable to the present disclosure.

[0056] Referring to FIG. 2, the UE (200) may include a processor (202), memory (204), a transceiver (206), one or more antennas (208), a power management module (241), a battery (242), a display (243), a keypad (244), a SIM (Subscriber Identification Module) card (245), a speaker (246), and a microphone (247).

[0057] The processor (202) may be configured to implement the descriptions, functions, procedures, proposals, methods, and / or flowcharts disclosed herein. The processor (202) may be configured to control one or more other components of the UE (200) to implement the descriptions, functions, procedures, proposals, methods, and / or flowcharts disclosed herein. A layer of a radio interface protocol may be implemented in the processor (202). The processor (202) may include an ASIC, other chipset, logic circuit, and / or data processing device. The processor (202) may be an application processor. The processor (202) may include at least one of a DSP, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), and a modem (modulator and demodulator).

[0058] Memory (204) is operatively coupled to the processor (202) and can store various information for operating the processor (202). Memory (204) may include ROM, RAM, flash memory, memory cards, storage media, and / or other storage devices. When the implementation is implemented in software, the techniques described herein may be implemented using modules (e.g., procedures, functions, etc.) that perform the descriptions, functions, procedures, suggestions, methods, and / or operational flowcharts disclosed herein. The modules may be stored in memory (204) and executed by the processor (202). Memory (204) may be implemented within the processor (202) or external to the processor (202), in which case it may be communicatively coupled to the processor (202) via various methods known in the art.

[0059] A transceiver (206) is operably coupled to the processor (202) and is capable of transmitting and / or receiving wireless signals. The transceiver (206) may include a transmitter and a receiver. The transceiver (206) may include baseband circuitry for processing radio frequency signals. The transceiver (206) may control one or more antennas (208) to transmit and / or receive wireless signals.

[0060] The power management module (241) can manage the power of the processor (202) and / or the transceiver (206). The battery (242) can supply power to the power management module (241).

[0061] The display (243) can output the results processed by the processor (202). The keypad (244) can receive input to be used by the processor (202). The keypad (244) can be displayed on the display (243).

[0062] A SIM card (245) is an integrated circuit that securely stores an International Mobile Subscriber Identity (IMSI) and associated keys, and can be used to identify and authenticate subscribers in mobile devices such as mobile phones and computers. Additionally, many SIM cards can store contact information.

[0063] The speaker (246) can output sound-related results processed by the processor (202). The microphone (247) can receive sound-related input to be used by the processor (202).

[0064] In implementations of this specification, a UE may operate as a transmitter in the uplink and as a receiver in the downlink. In implementations of this specification, a base station may operate as a receiver in the uplink and as a transmitter in the downlink. In this specification, a base station may be referred to as a Node B (Node B), an eNode B (eNB), or a gNB, and may not be limited to a specific form.

[0065] In addition, for example, the UE may be implemented in various forms depending on the use case / service. The UE may be composed of various components, devices / parts, and / or modules. For example, each UE may include a communication device, a control device, a memory device, and additional components. The communication device may include a communication circuit and a transceiver. For example, the communication circuit may include one or more processors and / or one or more memories. For example, the transceiver may include one or more transceivers and / or one or more antennas. The control device is electrically connected to the communication device, the memory device, and the additional components, and may control the overall operation of each UE. For example, the control device may control the electrical / mechanical operation of each UE based on a program / code / command / information stored in the memory device. The control device may transmit information stored in the memory device to an external device (e.g., another communication device) via the communication device via a wireless / wired interface, or may store information received from an external device (e.g., another communication device) via the communication device via a wireless / wired interface in the memory device.

[0066] Additional components may be configured in various ways depending on the type of UE. For example, the additional components may include at least one of a power unit / battery, an input / output (I / O) device (e.g., an audio I / O port, a video I / O port), a driving device, and a computing device. In addition, the UE is not limited thereto, and may be implemented in the form of a robot (100a in FIG. 1), a vehicle (100b-1 and 100b-2 in FIG. 1), an XR device (100c in FIG. 1), a portable device (100d in FIG. 1), a home appliance (100e in FIG. 1), an IoT device (100f in FIG. 1), a digital broadcasting terminal, a hologram device, a public safety device, an MTC device, a medical device, a fintech device (or a financial device), a security device, a climate / environmental device, an AI server / device (100g in FIG. 1), a base station (120 in FIG. 1), or a network node. UE can be used in mobile or fixed locations depending on the use case / service.

[0067] The various components, devices / parts, and / or modules of the UE may all be connected to each other via a wired interface, or at least some of them may be connected wirelessly via a communication device. In addition, each component, device / part, and / or module of the UE may further include one or more elements. For example, the control device may be configured by a set of one or more processors. For example, the control device may be configured by a set of a communication control processor, an application processor (AP), an electronic control unit (ECU), a graphics processing unit, and a memory control processor. As another example, the memory device may be configured by a random access memory (RAM), a dynamic random access memory (DRAM), a read-only memory (ROM), a flash memory, a volatile memory, a non-volatile memory, and / or a combination thereof.

[0068]

[0069] 5G system architecture applicable to the present disclosure

[0070] The 5G system is an advanced technology from the 4th generation LTE mobile communication technology. It supports new radio access technology (RAT: Radio Access Technology), extended LTE (eLTE) as an extended technology of LTE (Long Term Evolution), and non-3GPP (e.g., WLAN) access through the evolution or clean-state structure of the existing mobile communication network structure.

[0071] 5G systems are defined as service-based, and the interactions between network functions (NFs) within the architecture for 5G systems can be expressed in two ways as follows.

[0072] - Reference point representation: Represents the interaction between NF services within NFs described by a point-to-point reference point (e.g., N11) between two NFs (e.g., AMF and SMF).

[0073] Service-based representation: Network functions (e.g., AMF) within the control plane (CP) allow other authorized network functions to access their services. This representation also includes point-to-point reference points, if necessary.

[0074] 5GC (5G Core) can include various components, some of which include access and mobility management function (AMF), session management function (SMF), policy control function (PCF), user plane function (UPF), application function (AF), unified data management (UDM), and non-3GPP interworking function (N3IWF).

[0075] The UE connects to the data network via the UPF via the next-generation radio access network (NG-RAN) that includes the gNB. The UE can receive data services via untrusted non-3GPP access points, such as wireless local area networks (WLANs). To connect non-3GPP access points to the core network, an N3IWF may be deployed.

[0076] The N3IWF manages interworking between non-3GPP access and 5G systems. When a UE is connected to a non-3GPP access (e.g., WiFi, also known as IEEE 802.11), it can connect to a 5G system via the N3IWF. The N3IWF performs control signaling with the AMF and connects to the UPF via the N3 interface for data transmission.

[0077] AMF can manage access and mobility in 5G systems. It can also manage non-access stratum (NAS) security. It can also handle mobility in idle states.

[0078] The UPF functions as a gateway for transmitting and receiving user data. A UPF node can perform all or part of the user plane functions of a 4G mobile communications S-GW (serving gateway) and P-GW (packet data network gateway).

[0079] The UPF acts as a boundary point between the next generation RAN (NG-RAN) and the core network, and is an element that maintains the data path between the gNB and the SMF. In addition, the UPF acts as a mobility anchor point when the UE moves across the area served by the gNB. The UPF can perform the function of handling PDUs. For mobility within the NG-RAN (e.g., NG-RAN defined after 3GPP Release-15), the UPF can route packets. In addition, the UPF can also act as an anchor point for mobility with other 3GPP networks (e.g., RAN defined before 3GPP Release-15), such as UTRAN (UMTS (universal mobile telecommunications system) terrestrial radio access network), E-UTRAN (evolved-UTRAN), or GERAN (GSM (global system for mobile communication) / EDGE (enhanced data rates for global evolution) radio access network). A UPF may correspond to the termination point of a data interface toward a data network.

[0080] The PCF is a node that controls the operator's policies. The AF is a server that provides various services to UEs. The UDM is a server that manages subscriber information, similar to the HSS (home subscriber server) of 4G mobile communications. The UDM (460) stores and manages subscriber information in a unified data repository (UDR).

[0081] The SMF can perform the function of assigning an IP (Internet protocol) address to the UE. In addition, the SMF can control the PDU (protocol data unit) session.

[0082] For convenience of explanation below, the drawing symbols for AMF, SMF, PCF, UPF, AF, UDM, N3IWF, gNB, or UE may be omitted, and operation may be performed by referring to the matters described in standard documents published prior to this document.

[0083] Figure 3 illustrates an example of functional separation of NG-RAN and 5GC (5th generation core) applicable to the present disclosure.

[0084] Referring to Figure 3, the UE connects to a data network (DN) via a next-generation RAN. The control plane function (CPF) node performs all or part of the functions of the mobility management entity (MME) of 4G mobile communications, and all or part of the control plane functions of the serving gateway (S-GW) and the PDN gateway (P-GW). The CPF node includes the AMF and the SMF.

[0085] The UPF node functions as a gateway through which user data is transmitted and received.

[0086] The authentication server function (AUSF) authenticates and manages UEs. The Network Slice Selection Function (NSSF) is a node for network slicing, as described below.

[0087] The network exposure function (NEF) provides a mechanism to securely expose the services and functions of the 5G core.

[0088] The reference points shown in Fig. 3 are as follows. N1 represents a reference point between the UE and the AMF. N2 represents a reference point between the (R)AN and the AMF. N3 represents a reference point between the (R)AN and the UPF. N4 represents a reference point between the SMF and the UPF. N5 represents a reference point between the PCF and the AF. N6 represents a reference point between the UPF and the DN. N7 represents a reference point between the SMF and the PCF. N8 represents a reference point between the UDM and the AMF. N9 represents a reference point between the UPFs. N10 represents a reference point between the UDM and the SMF. N11 represents a reference point between the AMF and the SMF. N12 represents a reference point between the AMF and the AUSF. N13 represents a reference point between the UDM and the AUSF. N14 represents a reference point between the AMFs. N15 represents a reference point between a PCF and an AMF in a non-roaming scenario, and a reference point between an AMF and a PCF of a visited network in a roaming scenario. N16 represents a reference point between SMFs. N22 represents a reference point between an AMF and an NSSF. N30 represents a reference point between a PCF and an NEF. N33 may represent a reference point between an AF and an NEF, and the entities and interfaces described above may be configured with reference to those described in standard documents published before this document. N58 represents a reference point between an AMF and an NSSAAF. N59 represents a reference point between a UDM and an NSSAAF. N80 represents a reference point between an AMF and an NSACF. N81 represents a reference point between an SMF and an NSACF.

[0089] The radio interface protocol is based on the 3GPP radio access network standard. Horizontally, the radio interface protocol consists of the physical layer, data link layer, and network layer. Vertically, it is divided into the user plane for data information transmission and the control plane for control signaling.

[0090] Protocol layers can be divided into L1 (layer-1), L2 (layer-2), and L3 (layer-3) based on the three lower layers of the open systems interconnection (OSI) standard model, which is widely known in communication systems.

[0091] Below, the present disclosure describes each layer of the wireless protocol. Figure 4 illustrates an example of a general architecture of a 5G (5th generation) system applicable to the present disclosure.

[0092] Referring to FIG. 4, the AS (access stratum) layer may include a physical (PHY) layer, a medium access control layer, a radio link control (RLC) layer, a packet data convergence protocol (PDCP) layer, and a radio resource control (RRC) layer, and operations based on each layer may be performed by referring to matters described in standard documents published prior to this document.

[0093] Specific embodiments of the present invention

[0094] The present disclosure relates to a device and method for controlling network congestion in a wireless communication system. Specifically, the present disclosure relates to a device and method for preventing a terminal from retransmitting a request message for a period of time corresponding to the backoff timer value by transmitting a reason for rejecting the request and a backoff timer value to the terminal when the network is unable to process the request of a group terminal.

[0095]

[0096] According to the 3GPP 5G NAS protocol, the network has 5G mobility management (5GMM) functions and 5G session management (5GSM) functions. The 5GMM function is a function that manages general message transmission and reception between the terminal and the network and the mobility of the terminal, and the 5GSM function is a function that handles PDU sessions between the terminal and the network, that is, between the terminal and the SMF through the AMF. Accordingly, when a terminal requests data transmission to the network, the network determines whether the terminal's request can be processed based on several specified conditions. At this time, the several specified conditions include at least one of the terminal's subscription, network capacity, maximum data by guaranteed bit rate (GBR), maximum data rate by non-GBR, maximum data rate by single network slice selection assistance information (S-NSSAI), maximum data rate by data network name (DNN), and network policy. Additionally, the network determines whether it is possible to process the terminal's request based on at least one of a PLMN network failure, a Standalone Non-Public Network (SNPN) network failure, or a congestion control failure.

[0097] If the network cannot process the request of the terminal, the network transmits a rejection message including the cause of the request rejection, i.e., the reason for rejecting the request, to the terminal. In addition, the network can control the terminal not to retransmit the request to the network during the time corresponding to the back-off timer by notifying the terminal of the back-off time value. For example, when the network rejects the session establishment request (PDU session establishment request) of the terminal, the network transmits a PDU session establishment reject message including the rejection reason indicating insufficient resources for a specific slice and DNN, or insufficient resources for a specific slice and DNN. At this time, the network transmits the back-off timer value to the terminal to control the terminal not to send a PDU session establishment request message for data transmission to the network during the time corresponding to the back-off timer. This operation is performed in a registered PLMN, a subscribed SNPN, or all PLMNs and SNPNs.

[0098] Meanwhile, the 3GPP SA2 / CT1 (system aspects 2 / core network and terminals 1) working group (WG) defined a method for effective group management using the generic group management, exposure and communication enhancements (GMEC) world inequality database (WID). Specifically, the SA2 WG redefined a maximum group data rate, and assigned the PCF the function of monitoring the data rate of each group and controlling it so that the data rate of each group does not exceed the maximum group data rate.

[0099] Additionally, 3GPP TS23.501 defines control plane load control, congestion and overload control, and support exposure of DNN and S-NSSAI specific group parameters. 3GPP TS23.503 also defines group related policy control and 5G VN group management, and 3GPP TS24.501 defines handling of network rejection not due to congestion control.

[0100] However, procedures for overload control, admission control, and congestion control at the NAS level, as well as methods for handling PDU sessions, have not been proposed. To enforce data rates based on the maximum group data rate defined in SA2, new 5GMM and 5GSM procedures applicable to group terminals are required. Furthermore, similar to general PDU session handling, methods for overload control and congestion control that operate on specific terminals based on specific groups are required.

[0101] In particular, for group management using the current GMEC WID, the network notifies terminals of the LADN service area and the available LADN S-NSSAI and LADN DNN within the LADN service area through extended LADN information. Therefore, new 5GMM and 5GSM procedures are required to control overload and congestion for each group of terminals in the network.

[0102] Accordingly, the present disclosure proposes a technique for controlling congestion based on a LADN service area in a wireless communication system. Specifically, the present disclosure discloses a device and method for restricting network access of a terminal by transmitting a reason and a backoff timer value indicating that the request is rejected due to a lack of resources for the LADN S-NSSAI and LADN DNN when processing a request from a group terminal operating only in a specific LADN service area is impossible.

[0103] FIG. 5 illustrates an example of a congestion control procedure according to one embodiment of the present disclosure. FIG. 5 illustrates a method performed by a network. The network may include at least one network entity or network device that performs a network function, such as an AMF, SMF, NWDAF, and PCF.

[0104] Referring to Figure 5, in step S501, the network activates a congestion control function. In other words, if the network cannot process a request from a terminal operating only in a specific location based on a group, it activates (actives) a congestion control function based on the LADN service area. In one embodiment, the network can determine whether processing a request from a given terminal is possible based on resource information about the LADN S-NSSAI and LADN DNN within the LADN service area.

[0105] In step S503, the network receives a request from the terminal. In other words, the network can receive the request from the terminal while the congestion control function based on the LADN service area is activated. The request from the terminal may include a request message requiring network access or connection. For example, the request message may include at least one of a PDU session establishment request message, a PDU session modification request message, and a UL NAS transmission message related to the PDU session. The UL NAS transmission message related to the PDU session may include at least one of a UL NAS transmission message including a PDU session establishment request message or a PDU session modification request message.

[0106] In step S505, the network transmits a message including a rejection reason. In other words, if a terminal request is received while the LADN service area-based congestion control function is activated, the network determines that it cannot process the terminal request and transmits a message including a rejection reason for the request to the terminal. At this time, the rejection reason for the request may be configured to indicate insufficient resources for the LADN S-NSSAI and LADN DNN within the LADN service area. In addition, the message including the rejection reason may further include a backoff timer value for limiting the network access of the terminal. In one embodiment, the backoff timer value may be determined by operations, administration, and maintenance (OAM) or network local configuration, or by network training for the backoff timer value. In one embodiment, the backoff timer value may be determined based on various information from network entities such as the Network Data Analytics Function (NWDAF), AMF, SMF, PCF, etc.

[0107] FIG. 6 illustrates an example of an AMF congestion control procedure according to one embodiment of the present disclosure. FIG. 6 illustrates a method performed by the AMF. According to one embodiment, the operations of FIG. 6 may be understood as specific examples of FIG. 5.

[0108] Referring to FIG. 6, in step S601, the AMF activates the LADN service area-based congestion control function. In other words, the AMF may activate the LADN service area-based congestion control function based on the number of terminals requesting connection to the LADN service area, or based on an instruction or request from another entity within the network. For example, the AMF may activate the LADN service area-based congestion control function if the number of terminals already connected to the LADN service area plus the number of terminals requesting connection to the LADN service area is greater than the maximum number of terminals that can connect to the LADN service area. As another example, the AMF may receive an instruction from the NWDAF or PCF to activate the LADN service area-based congestion control function for terminals corresponding to the LADN S-NSSAI and LADN DNN of the LADN service area, and may activate the LADN service area-based congestion control function according to the received instruction. The maximum number of terminals that can connect to the LADN service area may be determined based on resources for the LADN S-NSSAI and LADN DNN within the LADN service area.

[0109] In step S603, the AMF checks whether a UL NAS transmission message is received from the terminal. For example, the AMF checks whether a UL NAS transmission message related to a PDU session is received from a terminal operating in the LADN service area when the LADN service area-based congestion control function is activated. The UL NAS transmission message related to the PDU session may include a UL NAS transmission message including a PDU session establishment request message or a PDU session modification request message.

[0110] When a UL NAS transmission message is received from the terminal, in step S605, the AMF transmits a DL NAS transmission message to the terminal. In other words, the AMF may transmit a DL NAS transmission message to the terminal in response to the UL NAS transmission message, without forwarding a message related to a PDU session included in the UL NAS transmission message to the SMF. At this time, the DL NAS transmission message may include at least one of a 5GMM rejection reason indicating insufficient resources for the LADN S-NSSAI and LADN DNN within the LADN service area and a backoff timer value therefor, in order to operate the backoff timer of the terminal.

[0111] FIG. 7 illustrates an example of a congestion control procedure of an SMF according to one embodiment of the present disclosure. FIG. 7 illustrates a method performed by an SMF. According to one embodiment, the operations of FIG. 7 may be understood as specific examples of FIG. 5.

[0112] Referring to Figure 7, in step S701, the SMF determines the number of terminals connected to the LADN service area. The SMF obtains terminal presence information within the LADN service area from the AMF and, based on the obtained terminal presence information, counts the number of terminals connected to the LADN service area.

[0113] In step S703, the SMF determines whether the number of connected terminals is less than the maximum number of terminals. In other words, the SMF can determine whether the number of terminals connected to the LADN service area is less than the maximum number of terminals that can be connected to the LADN service area.

[0114] If the number of connected terminals is less than the maximum number of terminals, the SMF accepts the connection request from the terminal in step S705. In other words, if the number of terminals connected to the LADN service area is less than the maximum number of terminals that can be connected to the LADN service area, the SMF determines that the LADN service area can process a connection request from another terminal and may accept the connection request from the other terminal. For example, the SMF may perform the necessary actions to establish a PDU session or modify a PDU session requested by the other terminal. The other terminal may be a terminal that operates only in a specific LADN service area based on a group.

[0115] If the number of connected terminals is greater than or equal to the maximum number of terminals, in step S707, the SMF performs a terminal disconnection or a connection request rejection. In other words, if the number of terminals connected to the LADN service area is greater than or equal to the maximum number of terminals that can be connected to the LADN service area, the SMF determines that it is impossible to process a connection request from another terminal in the LADN service area, and may disconnect a terminal already connected to the LADN service area or reject a connection request from another terminal. For example, the SMF may send a PDU session release command message to the already connected terminal, or a PDU session establishment rejection message or a PDU session modification rejection message to another terminal. At this time, the SMF may send the terminal a 5GSM rejection reason indicating insufficient resources for the LADN S-NSSAI and LADN DNN within the LADN service area and a backoff timer value therefor so that the terminal starts a backoff timer. The 5GSM rejection reason and the backoff timer value may be sent to the terminal via the PDU session release command message, the PDU session establishment rejection message, or the PDU session modification rejection message.

[0116]

[0117] FIG. 8 illustrates an example of a congestion control procedure of an SMF according to one embodiment of the present disclosure. FIG. 8 illustrates a method performed by an SMF. According to one embodiment, the operations of FIG. 8 may be understood as specific examples of FIG. 5.

[0118] Referring to Fig. 8, in step S801, the SMF receives an instruction to activate the congestion control function. In other words, the SMF can receive an instruction to activate the LADN service area-based congestion control function for a terminal corresponding to the LADN S-NSSAI and LADN DNN within the LADN service area from another network entity. The other network entity may be the NWDAF or the PCF. At this time, the SMF can activate the LADN service area-based congestion control function according to the activation instruction from the other network entity.

[0119] In step S803, the SMF checks whether a request related to a PDU session is received. In other words, the SMF checks whether a PDU session establishment request message or a PDU session modification request message is received from a terminal operating within the LADN service area.

[0120] When a request related to a PDU session is received, in step S805, the SMF transmits a rejection message for the request. That is, the SMF may transmit a PDU session establishment rejection message or a PDU session modification rejection message to a terminal operating within a LADN service area. At this time, the PDU session establishment rejection message or the PDU session modification rejection message may include a 5GSM rejection reason and a backoff timer value for the same to cause the terminal to start a backoff timer. The 5GSM rejection reason may be set to indicate insufficient resources for the LADN S-NSSAI and LADN DNN within the LADN service area.

[0121]

[0122] As described above, a network such as AMF or SMF can transmit a rejection reason and a backoff timer value to the terminal for a request. However, if the request received from the terminal is related to an emergency service, the network does not transmit a backoff timer value to the terminal. This is to prevent the LADN service area-based congestion control function from being applied to a request related to an emergency service, i.e., an emergency PDU session. According to one embodiment, if the request type of the request message received from the terminal is an initial emergency request type or an existing emergency PDU session type, the network determines that the request message is related to an emergency service and controls the message including the rejection reason not to include the backoff timer value.

[0123] Meanwhile, a terminal that has received a rejection reason and a backoff timer value for a request from the network starts a backoff timer corresponding to the LADN S-NSSAI, LADN DNN, and / or LADN service area, and restricts request transmission to the network based on the backoff timer. For example, the terminal does not initiate a PDU session establishment procedure or a PDU session modification procedure while the backoff timer is running or inactive, and controls the NAS transmission procedure for transmitting CIoT user data not to be initiated.

[0124] FIG. 9 illustrates an example of a request procedure of a terminal according to one embodiment of the present disclosure. FIG. 9 illustrates a method performed by a terminal.

[0125] Referring to FIG. 9, in step S901, the terminal transmits a connection request to the network. In other words, the terminal may transmit a request message requiring network access or connection to the network. The request message may include at least one of a PDU session establishment request message, a PDU session modification request message, and a UL NAS transmission message related to the PDU session. The UL NAS transmission message related to the PDU session may include at least one of a UL NAS transmission message including a PDU session establishment request message or a UL NAS transmission message including a PDU session modification request message.

[0126] In step S903, the terminal receives a message including a rejection reason. That is, the terminal may receive a message including a rejection reason for the request from the network. The message including the rejection reason may include at least one of a DL NAS transfer message, a PDU session establishment rejection message, or a PDU session modification rejection message. The rejection reason for the request may indicate insufficient resources for the LADN S-NSSAI and LADN DNN within the LADN service area.

[0127] In step S905, the terminal checks whether a backoff timer value is included. That is, the terminal checks whether a rejection message received from the network includes a backoff timer value.

[0128] If a backoff timer value is included, in step S907, the terminal retransmits the request after the backoff time has elapsed. If the rejection message includes a backoff timer value, the terminal can start a backoff timer corresponding to the backoff timer value and control that a request message requiring network access or connection is not transmitted to the network while the backoff timer is running, i.e., during the backoff time. In addition, when the backoff time has elapsed and the backoff timer has expired, the terminal can retransmit the request message to the network.

[0129] If the backoff timer value is not included, the terminal retransmits the request in step S909. If the rejection message does not include the backoff timer value, the terminal may retransmit the request message to the network regardless of the rejection reason included in the rejection message. In other words, even if the rejection message includes a rejection reason indicating insufficient resources for the LADN S-NSSAI and LADN DNN within the LADN service area, if the backoff timer value is not included, the terminal may immediately transmit the PDU session establishment request or PDU session request message.

[0130] As previously mentioned, the terminal shall not transmit any request messages requiring network access or connection to the network while the backoff timer is running. However, in the case of emergency services, the terminal may initiate the PDU session establishment procedure for emergency services even while the backoff timer is running.

[0131] In one embodiment, the terminal may be turned off during the operation of the backoff timer. In this case, the time value of the backoff timer is maintained. Accordingly, when the terminal is switched on, the backoff timer may be restarted and run for a period of time corresponding to the maintained time value.

[0132] For congestion control based on LADN service area as described above, the following can be defined.

[0133] According to one embodiment, the contents as defined in [Table 1] may be defined for a UL NAS transmission message initiated by a terminal.

[0134]

[0135] As shown in [Table 1], when a UL NAS transport message is received, the AMF may activate the LADN service area-based congestion control function for the LADN S-NSSAI and LADN DNN S-SNNAI based on the request type of the UL NAS transport message. When the LADN service area-based congestion control function is activated, the AMF may transmit to the terminal a 5GMM rejection reason and a backoff timer value indicating insufficient resources for the LADN S-NSSAI and LADN DNN within the LADN service area.

[0136]

[0137] According to one embodiment, the UL NAS transmission procedure initiated by the network may be defined as in [Table 2].

[0138]

[0139] As shown in [Table 2], when transmitting a single UL 5GSM message or a single UL CIoT user data container that is not delivered due to congestion control, the AMF may set a 5GMM rejection reason indicating insufficient resources for the LADN S-NSSAI and LADN DNN within the LADN service area.

[0140]

[0141] According to one embodiment, the contents of [Table 3] may be defined for a UL NAS transmission message initiated by the network.

[0142]

[0143] As shown in [Table 3], when a 5GMM rejection reason indicating insufficient resources for LADN S-NSSAI and LADN DNN is set in a DL NAS transmission message, the terminal may transmit an indication that the 5GSM message was not delivered due to S-NASSAI-based congestion control and the time value of the back-off timer to the 5GSM sublayer along with the 5GSM message included in the payload container IE of the DL NAS transmission message.

[0144]

[0145] According to one embodiment, the processing of LADN service areas and LADN S-NSSAI and LADN-based congestion control may be defined as in [Table 4].

[0146]

[0147] As shown in [Table 4], if the 5GS session management timer T358x is running or disabled in the terminal, the terminal does not initiate the PDU session establishment procedure, the PDU session modification procedure, or the NAS transmission procedure for transmitting CIoT user data.

[0148]

[0149] According to one embodiment, the 5GS session management timer T358x can be defined as in [Table 5].

[0150]

[0151] In one embodiment, the following may be defined for network rejection processing that is not due to congestion control: [Table 6].

[0152]

[0153]

[0154] According to one embodiment, the contents of [Table 7] may be defined for a PDU session release procedure requested by the network.

[0155]

[0156] As shown in [Table 7], the PDU Session Release Command message may include a rejection reason and a backoff timer value indicating insufficient resources for the LADN S-NSSAI and LADN DNN within the LADN service area. However, if the PDU Session Release Command message is transmitted to a UE configured with high priority access in a selected PLMN of the LADN service area or an SNPN of the LADN service area, the PDU Session Release Command message does not include a backoff timer value for PDU session establishment.

[0157]

[0158] According to one embodiment, the PDU session release procedure accepted by the terminal may be defined as in [Table 8].

[0159]

[0160] As shown in [Table 8], if the PDU Session Release Command message includes a 5GSM rejection reason indicating insufficient resources for the LADN S-NSSAI and LADN DNN within the LADN service area and does not include a backoff timer value, the UE may transmit another PDU Session Establishment Request message or PDU Session Modification Request message for the same S-NSSAI and DNN combination in the same LADN service area. In addition, if the 5GS session management timer T358x is running or deactivated, the UE may initiate a PDU session establishment procedure for emergency services.

[0161]

[0162] According to one embodiment, the contents of [Table 9] may be defined in relation to the PDU session establishment rejection message of SMF.

[0163]

[0164] As shown in [Table 9], if a connection with the requested DN is rejected by the network, the PDU session establishment rejection message may include a 5GSM rejection reason and a backoff timer value indicating insufficient resources for the LADN S-NSSAI and LADN DNN within the LADN service area.

[0165]

[0166] According to one embodiment, the contents as in [Table 10] may be defined for handling network rejection due to congestion control.

[0167]

[0168] As shown in [Table 10], when a PDU session modification rejection message including a 5GSM rejection reason and a backoff timer is received, or an indication indicating that a 5GSM message was not delivered due to a LADN service area is received together with a backoff timer and a PDU session modification request message, the terminal shall ignore the re-attempt indicator provided from the network and perform an action based on the backoff timer. Specifically, the terminal may control a timer T358x related to the S-NSSAI of the PDU session for the LADN service area or a timer T358x related to the S-NSSAI of the PDU session for the LADN DNN, or control not to transmit a PDU session establishment request message or a PDU session modification request message, based on at least one of a timer value, an S-NSSAI and a DNN provided during the PDU session, and a request type.

[0169]

[0170] According to one embodiment, the contents of [Table 11] may be defined for handling network rejection due to congestion control.

[0171]

[0172]

[0173] According to one embodiment, PDU session related messages can be defined as in [Table 12].

[0174]

[0175] As shown in [Table 12], the PDU Session Establishment Reject message, the PDU Session Modification Reject message, and / or the PDU Session Release Command message may include at least one of a backoff timer value and a retry indicator, based on whether the 5GSM rejection reason indicates insufficient resources for the LADN S-NSSAI and LADN DNN within the LADN service area.

[0176]

[0177] According to one embodiment, causes related to PLMN or SNPN specific network failures and congestion / authentication failures may be defined as in [Table 13].

[0178]

[0179]

[0180] It is clear that the examples of the proposed methods described above can also be considered as a type of proposed methods, as they can be included as one of the implementation methods of the present disclosure. Furthermore, the proposed methods described above can be implemented independently, but they can also be implemented in the form of a combination (or merge) of some of the proposed methods. Information regarding the applicability of the proposed methods (or information regarding the rules of the proposed methods) can be defined by a rule such that the base station notifies the terminal of the application of the proposed methods through a predefined signal (e.g., a physical layer signal or a higher layer signal).

[0181] The present disclosure may be embodied in other specific forms without departing from the technical ideas and essential features described herein. Therefore, the above detailed description should not be construed as limiting in all respects but rather as illustrative. The scope of the present disclosure should be determined by a reasonable interpretation of the appended claims, and all modifications within the equivalent scope of the present disclosure are intended to be included within the scope of the present disclosure. Furthermore, claims that do not explicitly cite each other in the claims may be combined to form embodiments or incorporated into new claims through post-filing amendments.

[0182] Embodiments of the present disclosure can be applied to various wireless access systems. Examples of various wireless access systems include the 3rd Generation Partnership Project (3GPP) or 3GPP2 systems.

[0183] The embodiments of the present disclosure can be applied not only to the various wireless access systems described above, but also to all technical fields that utilize these various wireless access systems. Furthermore, the proposed method can also be applied to mmWave and THz communication systems utilizing ultra-high frequency bands.

[0184] Additionally, embodiments of the present disclosure can be applied to various applications such as autonomous vehicles and drones.

Claims

1. In a method performed by a network in a wireless communication system, Steps to enable congestion control function; A step of receiving a request message from a terminal; and A step of transmitting a message including a reason for rejection of the above request message to the terminal, The above rejection reason is a method of indicating insufficient resources for LADN S-NSSAI (single network slice selection assistance information) and LADN DNN (data network name) within the LADN (local area data network) service area.

2. In claim 1, A method in which a message including the above rejection reason further includes a backoff timer value that restricts retransmission of the request message for a certain period of time.

3. In claim 2, A method in which, if the above request message is a message related to an emergency service, the message including the reason for rejection does not include the backoff timer value.

4. In claim 1, The above congestion control function is a method for controlling network congestion based on the LADN service area.

5. In claim 1, A method in which the above congestion control function is activated based on resources for the LADN S-NSSAI and LADN DNN within the LADN service area.

6. In claim 1, A method in which the congestion control function is activated based on at least one of the number of terminals connected to the LADN service area, the maximum number of terminals that can connect to the LADN service area, and the number of terminals requesting connection to the LADN service area.

7. In claim 1, A method wherein the above congestion control function is activated based on a request from at least one other network entity.

8. In claim 1, A method wherein the above network includes at least one of an access and mobility management function (AMF) or a session management function (SMF).

9. In claim 8, A method in which the AMF does not transmit a PDU session-related message included in the request message to the SMF when the request message is received while the congestion control function is activated.

10. In claim 1, A method wherein the request message includes at least one of a PDU session establishment request message, a PDU session modification request message, or a UL NAS transmission message related to a PDU session.

11. In claim 1, A method in which the message including the rejection reason includes at least one of a PDU session release command message, a PDU session establishment rejection message, a PDU session modification rejection message, or a DL NAS transmission message related to a PDU session.

12. In a method performed by a terminal in a wireless communication system, A step of sending a request message to the network; receiving a message including a reason for rejection of the request message from the network; and A step of controlling retransmission of the request message based on whether the message including the rejection reason includes a backoff timer value, The above rejection reason is a method of indicating insufficient resources for LADN S-NSSAI (single network slice selection assistance information) and LADN DNN (data network name) within the LADN (local area data network) service area.

13. In claim 12, The step of controlling the retransmission of the above request message is: If the message including the rejection reason includes the backoff timer value, a step of restricting the request message from being retransmitted for a time corresponding to the backoff timer value; and A method comprising the step of retransmitting the request message if the message including the rejection reason includes the backoff timer value.

14. In a network device in a wireless communication system, Transmitter and receiver; and A processor connected to the above transmitter and receiver is included, The above processor, Activate congestion control, Receive a request message from the terminal, Control to transmit a message including a reason for rejection of the above request message to the terminal, The above rejection reason is a network device indicating insufficient resources for LADN S-NSSAI (single network slice selection assistance information) and LADN DNN (data network name) within the LADN (local area data network) service area.

15. In a wireless communication system, at a terminal, Transmitter and receiver; and A processor connected to the above transmitter and receiver is included, The above processor, Send a request message to the network, Receive a message from the network containing a reason for rejection of the request message, and Controls retransmission of the request message based on whether the message containing the rejection reason includes a backoff timer value, The above rejection reason is a terminal indicating insufficient resources for LADN S-NSSAI (single network slice selection assistance information) and LADN DNN (data network name) within the LADN (local area data network) service area.

16. In communication devices, At least one processor; At least one computer memory connected to said at least one processor and storing instructions that direct operations when executed by said at least one processor, The above actions are, A step of sending a request message to the network; receiving a message including a reason for rejection of the request message from the network; and A step of controlling retransmission of the request message based on whether the message including the rejection reason includes a backoff timer value, The above rejection reason is a communication device indicating insufficient resources for LADN S-NSSAI (single network slice selection assistance information) and LADN DNN (data network name) within the LADN (local area data network) service area.

17. In a non-transitory computer-readable medium storing at least one instruction, comprising at least one instruction executable by the processor, At least one of the above commands causes the device to: Send a request message to the network, Receive a message from the network containing a reason for rejection of the request message, and Controls retransmission of the request message based on whether the message containing the rejection reason includes a backoff timer value, The above rejection reason is a computer-readable medium indicating insufficient resources for LADN S-NSSAI (single network slice selection assistance information) and LADN DNN (data network name) within the LADN (local area data network) service area.

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