Apparatus and method for controlling network congestion in wireless communication system

Abstract

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

Description

TECHNICAL FIELD

[0001] The present specification relates to a wireless communication system, and more particularly, to an apparatus and method for controlling network congestion in a wireless communication system. BACKGROUND

[0002] Wireless access systems are widely deployed to provide various kinds of communication services such as voice and data. Generally, a wireless access system is a multiple access system that can support communication by sharing the available system resources (bandwidth, transmission power, etc.) among multiple users. Examples of multiple access systems include code division multiple access (CDMA) systems, frequency division multiple access (FDMA) systems, time division multiple access (TDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency division multiple access (SC-FDMA) systems, etc.

[0003] In particular, since many communication devices require large communication capacity, an enhanced mobile broadband (eMBB) communication technology that improves compared to existing radio access technology (RAT) has been proposed. In addition, a communication system that not only considers massive machine type communication (mMTC) that connects multiple devices and objects to provide various services anytime and anywhere but also considers reliability and latency sensitive services / user equipment (UE) has been proposed. Various technical configurations for this purpose are being proposed. SUMMARY

[0004] TECHNICAL PROBLEM

[0005] The present disclosure relates to an apparatus and method for controlling network congestion in a wireless communication system.

[0006] The present disclosure relates to an apparatus and method for controlling overload and / or congestion of a group of wireless devices in a wireless communication system.

[0007] The present disclosure relates to an apparatus and method for controlling network congestion based on a local data network (LDAN) service area in a wireless communication system.

[0008] The present disclosure relates to an apparatus and method for indicating resource insufficiency for a LDAN service area within a single network slice selection assistance information (LADN S-NSSAI) and a LDAN data network name (DNN) in a wireless communication system.

[0009] The present disclosure relates to an apparatus and method for preventing network access of a group of wireless devices based on a back-off timer in a wireless communication system.

[0010] The technical objects to be achieved by the present disclosure are not limited to the aforementioned ones, and those skilled in the art to which the present disclosure pertains can consider other technical objects not mentioned above from the following embodiments of the present disclosure.

[0011] Technical Solution

[0012] In an embodiment of the disclosure, a method performed by a network in a wireless communication system includes activating a congestion control function, receiving a request message from a wireless device, and transmitting a message including a rejection cause for the request message to the wireless device, wherein the rejection cause indicates that resources are insufficient for a local data network (LADN) single network slice selection assistance information (S-NSSAI) and a LADN data network name (DNN) within a LADN service area.

[0013] In an embodiment of the disclosure, a method performed by a wireless device in a wireless communication system includes transmitting a request message to a network, receiving a message including a rejection cause for the request message from the network, and controlling retransmission of the request message based on whether the message including the rejection cause includes a back-off timer value, wherein the rejection cause indicates that resources are insufficient for a local data network (LADN) single network slice selection assistance information (S-NSSAI) and a LADN DNN within a LADN service area.

[0014] In an embodiment of the disclosure, a network device in a wireless communication system includes a transceiver, and a processor connected to the transceiver, wherein the processor controls to activate a congestion control function, receive a request message from a wireless device, and transmit a message including a rejection cause for the request message to the wireless device, and wherein the rejection cause indicates that resources are insufficient for a local data network (LADN) single network slice selection assistance information (S-NSSAI) and a LADN DNN within a LADN service area.

[0015] In an embodiment of the disclosure, a wireless device in a wireless communication system includes a transceiver, and a processor connected to the transceiver, wherein the processor controls to transmit a request message to a network, receive a message including a rejection cause for the request message from the network, and control retransmission of the request message based on whether the message including the rejection cause includes a back-off timer value, and wherein the rejection cause indicates that resources are insufficient for a local data network (LADN) single network slice selection assistance information (S-NSSAI) and a LADN DNN within a LADN service area.

[0016] In an embodiment of the disclosure, a communication device includes at least one processor; and at least one computer memory connected to the at least one processor and storing instructions based on execution of which by the at least one processor performs operations comprising: sending a request message to a network; receiving a message including a rejection cause for the request message from the network; and controlling retransmission of the request message based on whether the message including the rejection cause includes a fallback timer value, wherein the rejection cause indicates that resources are insufficient for a local data network (LADN) single network slice selection assistance information (S-NSSAI) and a LADN DNN within a LADN service area.

[0017] In an embodiment of the disclosure, a non-transitory computer readable medium storing at least one instruction, wherein the non-transitory computer readable medium includes the at least one instruction executable by a processor, wherein the at least one instruction causes a device to: send a request message to a network; receive a message including a rejection cause for the request message from the network; and control retransmission of the request message based on whether the message including the rejection cause includes a fallback timer value, and wherein the rejection cause indicates that resources are insufficient for a local data network (LADN) single network slice selection assistance information (S-NSSAI) and a LADN DNN within a LADN service area.

[0018] Advantageous Effects

[0019] Based on the embodiments of the disclosure, the following effects can be obtained. The disclosure can perform overload and congestion control for a group of wireless devices in a wireless communication system.

[0020] Effects obtainable from the embodiments of the disclosure are not limited to what has been described above, and other effects which are not described above can also be obtained by the technical configurations of the disclosure. That is, those skilled in the art can also derive intangible effects from the embodiments of the disclosure, which are not described above. BRIEF DESCRIPTION OF DRAWINGS

[0021] The following drawings are provided to assist in the understanding of the disclosure and can be provided together with the detailed description of the embodiments of the disclosure. However, technical features of the disclosure are not limited to specific drawings, and features disclosed in each drawing can be combined with each other to constitute new embodiments. Reference numerals in each drawing can indicate structural elements.

[0022] Figure 1 Examples applied to a communication system of the disclosure are exemplified.

[0023] Figure 2 Examples of a UE applicable to the present disclosure are illustrated.

[0024] Figure 3 Examples of a functional split between an NG-RAN and a Fifth Generation Core (5GC) applicable to the present disclosure are illustrated.

[0025] Figure 4 Examples of a general architecture of a Fifth Generation (5G) system applicable to the present disclosure are illustrated.

[0026] Figure 5 Examples of a congestion control procedure according to embodiments of the present disclosure are illustrated.

[0027] Figure 6 Examples of a congestion control procedure of an AMF according to embodiments of the present disclosure are illustrated.

[0028] Figure 7 Examples of a congestion control procedure of an SMF according to embodiments of the present disclosure are illustrated.

[0029] Figure 8 Examples of a congestion control procedure of an SMF according to embodiments of the present disclosure are illustrated.

[0030] Figure 9 Examples of a request procedure of a wireless device according to embodiments of the present disclosure are illustrated. DETAILED DESCRIPTION

[0031] The following embodiments are combinations of components and features of the present disclosure in predetermined forms. Each component or feature can be considered selectively applicable to the corresponding embodiments, unless otherwise explicitly described. Each component or feature can be implemented without being combined with other components or features. Also, a plurality of embodiments of the present disclosure can be configured by combining some components and / or features. The order of operations described in embodiments of the present disclosure can be changed. Some configurations or features of one embodiment can be included in another embodiment, or can be substituted with corresponding configurations or features of another embodiment.

[0032] In the description of the drawings, processes or steps that can obscure the gist of the present disclosure are not described, and processes or steps that can be understood by those skilled in the art are also not described.

[0033] Throughout this specification, when a part is referred to as “comprising” or “including” a component, it means that it may also include other components rather than exclude them, unless explicitly stated to the contrary. Furthermore, terms such as “unit,” “apparatus,” and “module” described in the specification refer to a unit that performs at least one function or operation, which may be implemented by hardware, software, or a combination of hardware and software. Additionally, the words “a,” “an,” “the,” and similar related terms may be used in the context of describing this disclosure (particularly in the context of the appended claims) to mean both singular and plural, unless otherwise stated herein or clearly contradicted by the context.

[0034] In this specification, embodiments of the present disclosure have been described regarding the data transmission and reception relationship between a base station and a mobile station. Here, a base station is understood as a terminal node of a network that communicates directly with a mobile station. Specific operations described herein as being performed by the base station may, in some cases, be performed by upper-layer nodes of the base station.

[0035] In other words, various operations for communicating with a mobile station in a network consisting of multiple network nodes, including a base station, can be performed by the base station or other network nodes besides the base station. In this case, "base station" can 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.

[0036] Furthermore, in embodiments of this disclosure, the term "terminal" may be replaced by terms such as User Equipment (UE), Mobile Station (MS), Subscriber Station (SS), Mobile Subscriber Station (MSS), Mobile Terminal, or Advanced Mobile Station (AMS).

[0037] Furthermore, the transmitting end refers to a fixed and / or mobile node that provides data or voice services, and the receiving end refers to a fixed and / or mobile node that receives data or voice services. Therefore, in the uplink case, the mobile station can be the transmitting end, and the base station can be the receiving end. Similarly, in the downlink case, the mobile station can be the receiving end, and the base station can be the transmitting end.

[0038] Implementations of this disclosure may be supported by standard documents disclosed in at least one of the radio access systems including the IEEE 802.xx system, the 3rd Generation Partnership Project (3GPP) system, the 3GPP Long Term Evolution (LTE) system, the 3GPP 5th Generation (5G) New Radio (NR) system, and the 3GPP2 system. Specifically, implementations of this disclosure may be supported by 3GPP Technical Specification (TS) 38.211, 3GPP TS 38.212, 3GPP TS 38.213, 3GPP TS 38.321, and 3GPP TS 38.331 documents.

[0039] Furthermore, the embodiments of this disclosure can be applied to other wireless access systems and are not limited to the systems described above. For example, they can be applied to systems subsequently used after 3GPP 5G NR systems, and are not limited to any particular system.

[0040] In other words, obvious steps or parts not described in the embodiments of this disclosure can be referred to the descriptions in the aforementioned documents. Furthermore, all terms disclosed in this document can be described using the aforementioned standard documents.

[0041] In the following, preferred embodiments according to this disclosure will be described in detail with reference to the accompanying drawings. The preferred embodiments will be described below in conjunction with the accompanying drawings. Figure 1 The detailed description disclosed herein is intended to describe exemplary embodiments of this disclosure and is not intended to represent the only implementation of the technical configurations of this disclosure.

[0042] In addition, specific terminology used in the embodiments of this disclosure is provided to aid in understanding this disclosure, and the use of such specific terminology may be changed to other forms without departing from the technical spirit of this disclosure.

[0043] The following technologies can be applied to various wireless access systems, such as 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).

[0044] For clarity, the following description is based on 3GPP communication systems (e.g., LTE, NR, etc.), but the technical spirit of this disclosure is not limited thereto. LTE can refer to technologies from 3GPP TS 36.xxx version 8 onwards. Specifically, LTE technologies from 3GPP TS 36.xxx version 10 onwards can be referred to as LTE-A, and LTE technologies from 3GPP TS 36.xxx version 13 onwards can be referred to as LTE-A pro. 3GPP NR can refer to technologies from TS 38.xxx version 15 onwards. 3GPP 6G can refer to technologies from TS version 17 and / or version 18 onwards. "xxx" refers to the detailed standard document number. LTE / NR / 6G can be collectively referred to as the 3GPP system.

[0045] For background information, terminology, abbreviations, etc., used in this disclosure, please refer to the descriptions in previously published standard documents. For example, refer to standard documents 36.xxx and 38.xxx.

[0046] For the terminology, abbreviations, and other background technologies that may be used in this document, please refer to the following standard documents previously published. Specifically, for LTE / Evolved Packet System (EPS) related terminology, abbreviations, and other background technologies, please refer to the 36.xxx series, 23.xxx series, and 24.xxx series; and for New Radio (NR) / 5G System (5GS) related terminology, abbreviations, and other background technologies, please refer to the 38.xxx series, 23.xxx series, and 24.xxx series.

[0047] In the following text, this specification is described based on the terminology defined above.

[0048] The three main demand areas for 5G include (1) enhanced mobile broadband (eMBB), (2) massive machine-type communications (mMTC) and (3) ultra-reliable and low-latency communications (URLLC).

[0049] Some use cases may require multiple regions for optimization, while others may focus on only one key performance indicator (KPI). 5G supports these diverse use cases in a flexible and reliable manner.

[0050] Communication systems applicable to this disclosure

[0051] While not limited thereto, the various descriptions, functions, processes, proposals, methods and / or operation flowcharts disclosed in this document can be applied to various fields requiring wireless communication / connectivity between devices (e.g., 5G).

[0052] More specific examples are illustrated below with reference to the accompanying drawings. In the following drawings / description, the same reference numerals may refer to the same or corresponding hardware blocks, software blocks, or functional blocks, unless otherwise described.

[0053] Figure 1 Examples of communication systems applied to this disclosure are illustrated.

[0054] Reference Figure 1 The communication system 100 applied in this disclosure includes wireless devices, base stations, and networks. Here, a wireless device refers to a device that performs communication using wireless access technologies (e.g., 5G NR, LTE) and may be referred to as a communication / wireless / 5G device. While not limited thereto, wireless devices may include robots 100a, vehicles 100b-1 and 100b-2, extended reality (XR) devices 100c, handheld devices 100d, home appliances 100e, Internet of Things (IoT) devices 100f, and artificial intelligence (AI) devices / servers 100g. For example, vehicles may include vehicles equipped with wireless communication capabilities, autonomous vehicles, vehicles capable of performing vehicle-to-vehicle communication, etc. Here, vehicles 100b-1 and 100b-2 may include unmanned aerial vehicles (UAVs) (e.g., drones). XR device 100c includes augmented reality (AR) / virtual reality (VR) / mixed reality (MR) devices, and can be implemented as a head-up display (HUD) installed in vehicles, televisions, smartphones, computers, wearable devices, home appliances, digital signage, vehicles, robots, etc. Handheld device 100d can include smartphones, smart tablets, wearable devices (e.g., smartwatches, smart glasses), computers (e.g., laptops, etc.). Home appliance 100e can include TVs, refrigerators, washing machines, etc. IoT device 100f can include sensors, smart meters, etc. For example, base station 120 and network 130 can also be implemented as wireless devices, and a specific wireless device 120a can operate as a base station / network node for other wireless devices.

[0055] Wireless devices 100a to 100f can connect to network 130 via base station 120. AI technology can be applied to wireless devices 100a to 100f, and wireless devices 100a to 100f can connect to AI server 100g via network 130. Network 130 can be configured using 3G, 4G (e.g., LTE), or 5G (e.g., NR) networks, etc. Wireless devices 100a to 100f can communicate with each other via base station 120 / network 130, but can also communicate directly (e.g., sidelink communication) without going through base station 120 / network 130. For example, vehicles 100b-1 and 100b-2 can perform direct communication (e.g., vehicle-to-vehicle (V2V) / vehicle-to-everything (V2X) communication). Furthermore, IoT device 100f (e.g., sensor) can communicate directly with other IoT devices (e.g., sensors) or other wireless devices 100a to 100f.

[0056] Wireless communication / connections 150a, 150b, and 150c can be established between wireless devices 100a to 100f / base station 120 and between base stations 120 / 120. Here, the wireless communication / connection can be implemented through various wireless access technologies (e.g., 5G NR), such as uplink / downlink communication 150a, sidelink communication 150b (or D2D communication), and inter-base station communication 150c (e.g., relay, integrated access backhaul (IAB)). Through wireless communication / connections 150a, 150b, and 150c, wireless devices and base stations / wireless devices, as well as base stations and base stations, can transmit / receive wireless signals to each other. For example, wireless communication / connections 150a, 150b, and 150c can transmit / receive signals through various physical channels. Therefore, based on various proposals of this disclosure, at least some of the following can be performed: various configuration information setting processes for wireless signal transmission / reception, various signal processing processes (e.g., channel coding / decoding, modulation / demodulation, resource mapping / demapping, etc.), resource allocation processes, etc.

[0057] Figure 2 Examples of UEs applicable to this disclosure are illustrated.

[0058] Reference Figure 2 The UE 200 may include a processor 202, a 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 subscriber identification module (SIM) card 245, a speaker 246, and a microphone 247.

[0059] Processor 202 may be configured to implement the descriptions, functions, processes, proposals, methods, and / or operational flowcharts disclosed herein. Processor 202 may be configured to control one or more other components of UE 200 to implement the descriptions, functions, processes, proposals, methods, and / or operational flowcharts disclosed herein. A wireless interface protocol layer may be implemented in processor 202. Processor 202 may include an ASIC, other chipsets, logic circuits, and / or data processing devices. Processor 202 may be an application processor. Processor 202 may include at least one of a DSP, a central processing unit (CPU), a graphics processing unit (GPU), and a modem (modulator and demodulator).

[0060] Memory 204 is operatively coupled to processor 202 and can store various information for operating processor 202. Memory 204 may include ROM, RAM, flash memory, memory card, storage medium, and / or other storage devices. When implemented in software, the techniques described herein can be implemented using modules (e.g., processes, functions, etc.) that perform the descriptions, functions, processes, proposals, methods, and / or operation flowcharts disclosed herein. Modules may be stored in memory 204 and executed by processor 202. Memory 204 may be implemented within or outside processor 202, in which case it may be communicatively coupled to processor 202 using various methods known in the art.

[0061] Transceiver 206 is operatively coupled to processor 202 and can transmit and / or receive wireless signals. Transceiver 206 may include a transmitter and a receiver. Transceiver 206 may include baseband circuitry for processing radio frequency signals. Transceiver 206 may control one or more antennas 208 to transmit and / or receive wireless signals.

[0062] The power management module 241 can manage the power used for the processor 202 and / or transceiver 206. The battery 242 can supply power to the power management module 241.

[0063] The display 243 can output the results processed by the processor 202. The keypad 244 can receive input for use by the processor 202. The keypad 244 can be displayed on the display 243.

[0064] The SIM card 245 is an integrated circuit used to securely store the International Mobile Subscriber Identity (IMSI) and related keys, and can be used to identify and authenticate subscribers in mobile devices such as mobile phones or computers. Furthermore, contact information can be stored on multiple SIM cards.

[0065] Speaker 246 can output sound-related results processed by processor 202. Microphone 247 can receive sound-related input for use by processor 202.

[0066] In the implementation described herein, the UE can operate as a transmitting device in the uplink and as a receiving device in the downlink. In the implementation described herein, the base station can operate as a receiving device in the UL and as a transmitting device in the DL. In this specification, the base station can be referred to as Node B, eNode B (eNB), or gNB, and is not limited to any specific form.

[0067] Furthermore, for example, the UE can be implemented in various forms depending on the use case / service. The UE can be configured from 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 communication circuitry and transceivers. For example, the communication circuitry 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, memory device, and additional components, and can control the overall operation of each UE. For example, the control device can control the electrical / mechanical operation of each UE based on programs / code / instructions / information stored in the memory device. The control device can transmit information stored in the memory device to external sources (e.g., other communication devices) via a wireless / wired interface through the communication device, or store information received from external sources (e.g., other communication devices) in the memory device via a wireless / wired interface through the communication device.

[0068] Additional components can be configured differently depending on the type of UE. For example, additional components may include at least one of a power unit / battery, input / output (I / O) devices (e.g., audio I / O ports, video I / O ports), drive units, and computing units. Furthermore, the UE can be implemented in, but is not limited to, the following forms: robot (…). Figure 1 100a in the middle), vehicles ( Figure 1 100b-1 and 100b-2 in the series), XR device ( Figure 1 100c in the middle), portable device ( Figure 1 100d in the middle), household appliances ( Figure 1 100e in the middle), IoT devices ( Figure 1 100f), digital broadcasting terminals, holographic devices, public safety devices, MTC devices, medical devices, fintech devices (or financial devices), security devices, climate / environment devices, AI servers / devices ( Figure 1 100g in the middle), base station ( Figure 3(120 in the middle) network nodes. The UE can be used in mobile or fixed locations depending on the use case / service.

[0069] All the various components, devices / parts, and / or modules of the UE can be connected to each other via wired interfaces, or at least some can be wirelessly connected via communication devices. Furthermore, each component, device / part, and / or module of the UE may include one or more elements. For example, the control unit may be configured with one or more processor groups. For instance, the control unit may be configured with a group of communication control processors, application processors (APs), electronic control units (ECUs), graphics processing units, and memory control processors. As another example, the memory device may be configured with RAM, dynamic RAM (DRAM), ROM, flash memory, volatile memory, non-volatile memory, and / or combinations thereof.

[0070] 5G system architecture applicable to this disclosure

[0071] 5G systems are advanced technologies derived from fourth-generation LTE mobile communication technology. They support new radio access technologies (RATs), extended LTE (eLTE) as an extension of LTE, and non-3GPP (e.g., WLAN) access through the evolution or clean state architecture of existing mobile communication networks.

[0072] 5G systems are service-defined, and the interaction between network functions (NFs) within the 5G system architecture can be represented in the following two ways: - Reference point representation: Represents the interaction between NF services within an NF 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 within the control plane (CP) (e.g., AMF) allow other authorized network functions to access their services. This representation may also include point-to-point reference points where necessary.

[0074] The 5G core (5GC) can include various components, including 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 Interoperability Function (N3IWF).

[0075] The UE connects to the data network via a UPF through a Next Generation Radio Access Network (NG-RAN) including a gNB. The UE can receive data services through untrusted non-3GPP access, such as a Wireless Local Area Network (WLAN). To connect non-3GPP access to the core network, an N3IWF can be deployed.

[0076] The N3IWF manages interoperability between non-3GPP access points and 5G systems. When a UE connects to a non-3GPP access point (e.g., WiFi known as IEEE 802.11), the UE can connect to the 5G system via the N3IWF. The N3IWF communicates with the AMF (Advanced Management Function) for control signaling and connects to the UPF (Uplink Function) via the N3 interface for data transmission.

[0077] AMF can manage access and mobility in 5G systems. AMF can perform functions to manage Non-Access Stratum (NAS) security. AMF can perform functions to handle mobility in idle states.

[0078] UPF performs gateway functions for sending and receiving user data. UPF nodes can perform all or part of the user plane functions of a Serving Gateway (S-GW) and Packet Data Network Gateway (P-GW) for fourth-generation mobile communications.

[0079] The UPF serves as the 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. Furthermore, the UPF acts as a mobility anchor point when the UE moves across an area served by the gNB. The UPF can perform the function of disposing of PDUs. For mobility within the NG-RAN (e.g., NG-RAN defined after 3GPP Release 15), the UPF can route packets. Additionally, the UPF can serve as an anchor point for mobility with other 3GPP networks (e.g., RANs defined before 3GPP Release 15), such as UMTS (Universal Mobile Telecommunications System) Terrestrial Radio Access Network (UTRAN), Evolved UTRAN (E-UTRAN), or GSM (Global System for Mobile Communications) / EDGE (Global Evolution Enhanced Data Rate) Radio Access Network (GERAN). The UPF can correspond to the termination point of the data interface toward the data network.

[0080] PCF is the node that controls operator policies. AF is the server that provides various services to UE. UDM is the server that manages subscriber information, such as the Home Subscriber Server (HSS) in fourth-generation mobile communications. UDM 460 stores and manages subscriber information in the Unified Data Repository (UDR).

[0081] The SMF can perform the function of allocating Internet Protocol (IP) addresses to UEs. Furthermore, the SMF can control Protocol Data Unit (PDU) sessions.

[0082] For ease of description below, reference numerals for AMF, SMF, PCF, UPF, AF, UDM, N3IWF, gNB, or UE may be omitted, and reference may be made to the descriptions in standard documents previously published in this document.

[0083] Figure 3 An example of functional separation between NG-RAN and fifth-generation core (5GC) applicable to this disclosure is illustrated.

[0084] Reference Figure 3 The UE connects to the data network (DN) via the next-generation RAN. Control plane function (CPF) nodes perform all or part of the functions of the mobility management entity (MME) for fourth-generation mobile communications, as well as all or part of the control plane functions of the serving gateway (S-GW) and PDN gateway (P-GW). CPF nodes include the AMF and SMF.

[0085] UPF nodes perform the functions of a gateway through which user data is sent and received.

[0086] The Authentication Server Function (AUSF) authenticates and manages the UE. The Network Slice Selection Function (NSSF) is a node used for network slicing as described below.

[0087] Network Open Function (NEF) provides a mechanism to securely open up 5G core services and functions.

[0088] Figure 4 The reference points shown are as follows: N1 represents the reference point between the UE and AMF. N2 represents the reference point between (R)AN and AMF. N3 represents the reference point between (R)AN and UPF. N4 represents the reference point between SMF and UPF. N5 represents the reference point between PCF and AF. N6 represents the reference point between UPF and DN. N7 represents the reference point between SMF and PCF. N8 represents the reference point between UDM and AMF. N9 represents the reference point between UPFs. N10 represents the reference point between UDM and SMF. N11 represents the reference point between AMF and SMF. N12 represents the reference point between AMF and AUSF. N13 represents the reference point between UDM and AUSF. N14 represents the reference point between AMFs. N15 represents the reference point between PCF and AMF in non-roaming scenarios, and the reference point between AMF and PCF of the visited network in roaming scenarios. N16 represents the reference point between SMFs. N22 represents the reference point between AMF and NSSF. N30 represents the reference point between PCF and NEF. N33 can represent the reference point between AF and NEF, and the above entities and interfaces can be configured with reference to the descriptions in the standard documents previously published in this document. N58 represents the reference point between AMF and NSSAAF. N59 represents the reference point between UDM and NSSAAF. N80 represents the reference point between AMF and NSACF. N81 represents the reference point between SMF and NSACF.

[0089] The radio interface protocol is based on the 3GPP radio access network specification. The radio interface protocol consists of a physical layer, a data link layer, and a network layer horizontally, and is vertically divided into a user plane for data information transmission and a control plane for control signal (signaling) transmission.

[0090] The protocol layer can be divided into L1 (layer-1), L2 (layer-2), and L3 (layer-3) based on the three layers of the Open Systems Interconnection (OSI) reference model, which is widely known in communication systems.

[0091] Each wireless protocol layer is described below. Figure 4 An example of a general architecture applicable to the fifth-generation (5G) system of this disclosure is illustrated.

[0092] Reference DETAILED DESCRIPTION The access layer (AS) may include the physical (PHY) layer, the medium access control layer, the radio link control (RLC) layer, the packet data convergence protocol (PDCP) layer, and the radio resource control (RRC) layer, and the operation of each layer can be referenced to the descriptions in the standard documents previously published in this document.

[0093] Figure 5

[0094] This disclosure relates to apparatus and methods for controlling network congestion in a wireless communication system. Specifically, this disclosure relates to apparatus and methods for preventing wireless devices from retransmitting request messages within a time period corresponding to a backoff timer value by sending a rejection reason and a backoff timer value to the wireless devices when the network is unable to process requests from a group of wireless devices.

[0095] According to the 3GPP 5G NAS protocol, the network has 5G Mobility Management (5GMM) and 5G Session Management (5GSM) functions. 5GMM manages general message sending and receiving between radio devices and the network, as well as the mobility of radio devices. 5GSM handles PDU sessions between radio devices and the network (i.e., via the AMF, between the radio device and the SMF). Therefore, when a radio device requests data transmission from the network, the network determines whether it can process the request based on several specified conditions. These conditions include at least one of the following: radio device subscription, network capacity, maximum data per Guaranteed Bit Rate (GBR), maximum data rate per non-GBR, maximum data rate per Single Network Slice Selection Assist Information (S-NSSAI), maximum data rate per Data Network Name (DNN), or network policy. Additionally, the network determines whether it can process the request based on at least one of the following: PLMN network failure, Independent Non-Public Network (SNPN) network failure, or congestion control failure.

[0096] When it is impossible to process a request from a wireless device, the network sends a rejection message to the wireless device including a reason for the request rejection (i.e., the reason for rejecting the request). Additionally, the network can notify the wireless device of a fallback timer value, thereby preventing the wireless device from retransmitting the request to the network during the period corresponding to the fallback time. For example, when the network rejects a wireless device's session establishment request (PDU session establishment request), the network sends a PDU session establishment rejection message to the wireless device, which includes a rejection reason indicating insufficient resources for a specific slice and DNN, or insufficient resources for a specific slice. At this time, the network sends a fallback timer value to the wireless device, thereby controlling the wireless device not to send PDU session establishment request messages for data transmission to the network during the period corresponding to the fallback timer. This operation is performed in a registered PLMN, a subscribed SNPN, or all PLMNs and SNPNs.

[0097] Furthermore, the 3GPP Systems Side 2 / Core Network and Radio Equipment 1 (SA2 / CT1) Working Group (WG) defines a method for efficiently managing groups using the Common Group Management, Exposure, and Communication Enhancement (GMEC) Work Item Description (WID). Specifically, SA2WG redefines the maximum group data rate and assigns a Policy Control Function (PCF) to monitor and control the data rate of each group, ensuring that the data rate does not exceed the maximum group data rate.

[0098] In addition, 3GPP TS23.501 defines control plane load control, congestion and overload control, and supports the exposure of DNN and S-NSSAI specific group parameters. Although 3GPP TS 24.501 defines the handling of network rejections not caused by congestion control, 3GPP TS 23.503 still defines group-related policy control and 5G VN group management.

[0099] However, no procedures or methods have yet been proposed for PDU session handling, including congestion control, admission control, and overload control at the NAS level. To apply data rates based on the maximum group data rate defined in SA2, new 5GMM and 5GSM procedures applicable to a group of radio devices are needed. Furthermore, similar to general PDU session handling, methods for overload and congestion control are required for operation of specific radio devices based on a specific group.

[0100] Specifically, for group management using the current GMEC WID, the network informs radio devices 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 needed to control overload and congestion for each group of radio devices in the network.

[0101] Therefore, this disclosure proposes a technique for controlling congestion in a wireless communication system based on LADN service area. Specifically, this document discloses apparatus and methods for preventing network access of a wireless device when processing a request from a group of wireless devices operating only in a specific LADN service area is impossible, by sending an indication in the network to the wireless device of the reason for rejecting the request due to a lack of resources for LADN S-NSSAI and LADN DNN, along with a backoff timer value.

[0102] Figure 5 An example of a congestion control process according to an embodiment of the present disclosure is illustrated. Figure 5 The method performed by a network is illustrated. The network may include at least one network entity or network device that performs network functions, such as AMF, SMF, NWDAF, or PCF.

[0103] Reference Figure 6 In step S501, the network activates congestion control functionality. In other words, if the network cannot process requests from group-based wireless devices operating only at specific locations, the network activates congestion control functionality based on the LADN service area. According to an implementation, the network can determine whether it can process requests from wireless devices based on resource information about LADN S-NSSAI and LADN DNN within the LADN service area.

[0104] In step S503, the network receives a request from the wireless device. In other words, the network can receive a request from the wireless device when the LADN service area-based congestion control function is activated. The request from the wireless device may include a request message requesting network access or connection. For example, the request message may include at least one of a UL NAS transmission message associated with a PDU session, a PDU session modification request message, or a PDU session establishment request message. The UL NAS transmission message associated with a PDU session may include at least one of a PDU session establishment request message or a UL NAS transmission message including a PDU session modification request message.

[0105] In step S505, the network sends a message including a rejection reason. In other words, if a request from a wireless device is received while congestion control based on the LADN service area is activated, the network determines that it cannot process the request from the wireless device and sends a message to the wireless device including a rejection reason for the request. The rejection reason for the request can be configured to indicate insufficient resources for LADN S-NSSAI and LADN DNN within the LADN service area. Additionally, the message including the rejection reason may also include a fallback timer value for restricting network access for the wireless device. In implementations, the fallback timer value can be determined through Operation, Administration and Maintenance (OAM) or network-local configuration, or through network training targeting the fallback timer value. In implementations, the fallback timer value can be determined based on various information from network entities such as NWDAF, AMF, SMF, PCF, etc.

[0106] Figure 6 An example of a congestion control process for an AMF according to an embodiment of the present disclosure is illustrated. Figure 6 An example of a method performed by AMF is illustrated. In the implementation, Figure 5 The operation can be understood as Figure 6 Specific examples.

[0107] Reference Figure 7 In step S601, the AMF activates the LADN service area-based congestion control function. In other words, the AMF can activate the LADN service area-based congestion control function based on the number of wireless devices requesting to connect to the LADN service area or based on an instruction or request from another entity in the network. For example, if the number of wireless devices already connected to the LADN service area plus the number of wireless devices requesting to connect to the LADN service area exceeds the maximum number of wireless devices that can connect to the LADN service area, the AMF can activate the LADN service area-based congestion control function. As another example, the AMF can receive an instruction from the NWDAF or PCF to activate the LADN service area-based congestion control function for wireless devices corresponding to the LADN S-NSSAI and LADN DNN within the LADN service area, and can activate the LADN service area-based congestion control function based on the received instruction. The maximum number of wireless devices that can connect to the LADN service area can be determined based on the resources available for the LADN S-NSSAI and LADN DNN within the LADN service area.

[0108] In step S603, the AMF determines whether a UL NAS transmission message has been received from the radio device. For example, when congestion control based on the LADN service area is activated, the AMF determines whether a UL NAS transmission message related to a PDU session has been received from a radio device operating in the LADN service area. The UL NAS transmission message related to the PDU session may include a UL NAS transmission message containing a PDU session establishment request message or a PDU session modification request message.

[0109] If a UL NAS transmission message is received from the radio device, in step S605, the AMF sends a DLNAS transmission message to the radio device. In other words, the AMF may not forward the PDU session-related messages included in the UL NAS transmission message to the SMF, but may instead send a DL NAS transmission message to the radio device in response to the UL NAS transmission message. In this case, the DL NAS transmission message may include at least one of a 5GMM rejection reason indicating insufficient resources for LADN S-NSSAI and LADN DNN within the LADN service area, or a corresponding backoff timer value for activating the backoff timer of the radio device.

[0110] Figure 7 An example of a congestion control process for an SMF according to an embodiment of the present disclosure is illustrated. Figure 7 An example of a method executed by SMF is illustrated. According to the implementation, Figure 5 The operation can be understood as Figure 7 Specific examples.

[0111] Reference Figure 8 In step S701, the SMF determines the number of wireless devices connected to the LADN service area. The SMF can obtain wireless device presence information within the LADN service area from the AMF, and can count the number of wireless devices connected to the LADN service area based on the obtained wireless device presence information.

[0112] In step S703, the SMF determines whether the number of connected wireless devices is less than the maximum number of wireless devices. In other words, the SMF can determine whether the number of wireless devices connected to the LADN service area is less than the maximum number of wireless devices that can connect to the LADN service area.

[0113] If the number of connected wireless devices is less than the maximum number of wireless devices, then in step S705, the SMF accepts connection requests from the wireless devices. In other words, if the number of wireless devices connected to the LADN service area is less than the maximum number of wireless devices that can connect to the LADN service area, the SMF determines that it can process connection requests from other wireless devices in the LADN service area and can accept connection requests from other wireless devices. For example, the SMF can perform operations necessary for PDU session establishment or PDU session modification requested by other wireless devices. Other wireless devices can be group-based wireless devices that operate only in a specific LADN service area.

[0114] If the number of connected wireless devices is greater than or equal to the maximum number of wireless devices, in step S707, the SMF disconnects the wireless devices or rejects their connection requests. In other words, if the number of wireless devices connected to the LADN service area is greater than or equal to the maximum number of wireless devices that can connect to the LADN service area, the SMF determines that it is impossible to process a connection request from another wireless device in the LADN service area, and can disconnect a wireless device already connected to the LADN service area or reject a connection request from another wireless device. For example, the SMF can send a PDU session release command message to an already connected wireless device, or send a PDU session establishment rejection message or a PDU session modification rejection message to another wireless device. At this time, the SMF can send a 5GSM rejection reason indicating insufficient resources for LADN S-NSSAI and LADN DNN in the LADN service area, along with its fallback timer value, causing the wireless device to start a fallback timer. The 5GSM rejection reason and fallback timer value can be sent to the wireless device via a PDU session release command message, a PDU session establishment rejection message, or a PDU session modification rejection message.

[0115] Figure 8 An example of a congestion control process for an SMF according to an embodiment of the present disclosure is illustrated. Figure 8 An example of a method executed by SMF is illustrated. According to the implementation, Figure 5 The operation can be understood as Figure 8 Specific examples.

[0116] Reference Figure 9In step S801, the SMF receives an instruction to activate the congestion control function. In other words, the SMF can receive an instruction from another network entity to activate the LADN-based congestion control function for radio devices corresponding to LADN S-NSSAI and LADN DNN within the LADN service area. This other network entity can be an NWDAF or a PCF. In this case, the SMF can activate the LADN-based congestion control function based on the activation instruction from the other network entity.

[0117] In step S803, the SMF determines whether a request related to a PDU session has been received. In other words, the SMF determines whether a PDU session establishment request message or a PDU session modification request message has been received from a radio device operating within the LADN service area.

[0118] Upon receiving a request related to a PDU session, in step S805, the SMF sends a rejection message for the request. Specifically, the SMF may send a PDU session establishment rejection message or a PDU session modification rejection message to the radio device operating within the LADN service area. The PDU session establishment rejection message or PDU session modification rejection message may include a 5GSM rejection reason and a corresponding backoff timer value for activating the backoff timer. The 5GSM rejection reason may be configured to indicate insufficient resources for LADN S-NSSAI and LADN DNN within the LADN service area.

[0119] As described above, networks such as AMF or SMF can send a rejection reason and a fallback timer value to the radio device for a request. However, if the request received from the radio device is related to an emergency service, the network does not send a fallback timer value to the radio device. This is to prevent congestion control functions based on the LADN service area from being applied to requests related to emergency services (i.e., emergency PDU sessions). According to an implementation, if the request type of the request message received from the radio device is an initial emergency request type or an existing emergency PDU session type, the network can determine that the request message is related to an emergency service, and control the message including the rejection reason to exclude the fallback timer value.

[0120] Furthermore, upon receiving a rejection reason and a fallback timer value for a request from the network, the wireless device starts a fallback timer corresponding to the LADN S-NSSAI, LADN DNN, and / or LADN service area, and prevents request transmission to the network based on the fallback timer. For example, when the fallback timer is running or deactivated, the wireless device does not initiate a PDU session establishment process or a PDU session modification process, and controls the initiation of NAS transmission processes for sending CIoT user data.

[0121] Figure 9 An example of a request process for a wireless device according to an embodiment of the present disclosure is illustrated. Figure 9 An example of a method performed by a wireless device is shown.

[0122] Reference ​ In step S901, the wireless device sends a connection request to the network. In other words, the wireless device can send a request message requesting network access or connection. The request message may include at least one of a UL NAS transmission message related to a PDU session, a PDU session modification request message, or a PDU session establishment request message. The UL NAS transmission message related to a PDU session may include at least one of a UL NAS transmission message containing a PDU session establishment request message or a UL NAS transmission message containing a PDU session modification request message.

[0123] In step S903, the wireless device receives a message including a rejection reason. That is, the wireless device can receive a message from the network including a rejection reason for the request. The message including the rejection reason may include at least one of a DL NAS transmission 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 LADN S-NSSAI and LADN DNN within the LADN service area.

[0124] In step S905, the wireless device determines whether a backoff timer value is included. That is, the wireless device determines whether the rejection message received from the network includes a backoff timer value.

[0125] If a backoff timer value is included, then in step S907, the wireless device retransmits the request after the backoff time has elapsed. If the rejection message includes a backoff timer value, the wireless device can start a backoff timer corresponding to the backoff timer value and control it to prevent sending a request message for network access or connection to the network while the backoff timer is running (i.e., during the backoff time). Furthermore, the wireless device can retransmit the request message to the network when the backoff time has elapsed and the backoff timer has expired.

[0126] If the backoff timer value is not included, the wireless device retransmits the request in step S909. If the rejection message does not include the backoff timer value, the wireless device can retransmit the request message to the network regardless of whether the rejection message includes a rejection reason. In other words, even if the rejection message includes a rejection reason indicating insufficient resources for LADN S-NSSAI and LADN DNN within the LADN service area, the wireless device can still immediately send a PDU session establishment request or PDU session request message if it does not include the backoff timer value.

[0127] As mentioned above, when the fallback timer is running, the wireless device does not send request messages for network access or connection. However, for emergency services, the wireless device can initiate a PDU session establishment process even when the fallback timer is running.

[0128] According to one implementation, the wireless device can be turned off while the rollback timer is running. In this case, the rollback timer's time value is maintained. Therefore, when the wireless device is turned on, the rollback timer can be restarted and run for a period corresponding to the maintained time value.

[0129] For congestion control based on LADN service areas as described above, the following can be defined.

[0130] In the implementation, the content defined in [Table 1] can be defined for UL NAS transmission messages initiated by the wireless device.

[0131] [Table 1]

[0132] As shown in [Table 1], when a UL NAS transmission message is received, the AMF can activate the LADN service area-based congestion control function for LADN S-NSSAI and LADN DNN S-SNNAI based on the request type of the UL NAS transmission message. When the LADN service area-based congestion control function is activated, the AMF can send a 5GMM rejection reason indicating insufficient resources for LADN S-NSSAI and LADN DNN within the LADN service area, along with a backoff timer value, to the radio device.

[0133] According to the implementation method, the contents in [Table 2] can be defined for the network-initiated UL NAS transmission process.

[0134] [Table 2]

[0135] As shown in [Table 2], when sending a single UL CIoT user data container or a single UL 5GSM message that is not delivered due to congestion control, the AMF can configure a 5GMM rejection reason that indicates insufficient resources for LADN S-NSSAI and LADN DNN within the LADN service area.

[0136] According to the implementation method, the contents in [Table 3] can be defined for UL NAS transmission messages initiated by the network.

[0137] [Table 3]

[0138] As shown in [Table 3], if the DL NAS transmission message is configured with an indication of the 5GMM rejection reason for insufficient resources for LADN S-NSSAI and LADNDNN, the radio device can send to the 5GSM sublayer an indication that the 5GSM message was not delivered due to congestion control based on S-NSSAI, a backoff timer value, and the 5GSM message included in the payload container IE of the DL NAS transmission message.

[0139] According to the implementation method, the contents of [Table 4] can be defined for handling LADN service areas and congestion control based on LADNS-NSSAI and LADN.

[0140] [Table 4]

[0141] As shown in [Table 4], if the 5GS session management timer (T358x) is running or disabled in the UE, the UE will not initiate the PDU session establishment process, PDU session modification process or NAS transmission process for sending CIoT user data.

[0142] According to the implementation method, the 5GS session management timer T358x can be defined as shown in [Table 5].

[0143] [Table 5]

[0144] According to the implementation method, the contents of [Table 6] can be defined for network rejections that are not caused by congestion control.

[0145] [Table 6]

[0146] According to the implementation method, the contents in [Table 7] can be defined for the PDU session release process requested by the network.

[0147] [Table 7]

[0148] As shown in [Table 7], the PDU session release command message may include a rejection reason indicating insufficient resources for LADNS-NSSAI and LADN DNN within the LADN service area, as well as a fallback timer value. However, if the PDU session release command message is sent to a radio device configured for high-priority access in a selected PLMN or SNPN within the LADN service area, the PDU session release command message does not include the fallback timer value for PDU session establishment.

[0149] According to the implementation method, the contents in [Table 8] can be defined for the PDU session release process received by the wireless device.

[0150] [Table 8]

[0151] As shown in [Table 8], if the PDU session release command message includes a 5GSM rejection reason indicating insufficient resources for LADNS-NSSAI and LADN DNN within the LADN service area and does not include a fallback timer value, the radio device can send another PDU session establishment request message or PDU session modification request message for the same S-NSSAI and DNN combination within the same LADN service area. Furthermore, if the 5GS session management timer T358x is running or disabled, the radio device can initiate a PDU session establishment procedure for emergency services.

[0152] According to the implementation method, the contents of the rejection message definition [Table 9] can be established for the SMF's PDU session.

[0153] [Table 9]

[0154] As shown in [Table 9], if the connection to the requested DN is rejected by the network, the PDU session establishment rejection message may include a 5GSM rejection reason and a fallback timer value, the 5GSM rejection reason indicating insufficient resources for LADNS-NSSAI and LADN DNN within the LADN service area.

[0155] According to the implementation method, the contents of [Table 10] can be defined to handle network denials caused by congestion control.

[0156] [Table 10]

[0157] As shown in [Table 10], if a PDU session modification rejection message including a 5GSM rejection reason and a fallback timer is received, or if an indication indicating that a 5GSM message was not delivered due to the LADN service area is received along with a fallback timer and a PDU session modification request message, the radio device should ignore the retry indicator provided by the network and perform the operation based on the fallback timer. Specifically, the radio device may control the timer T358x associated with the S-NSSAI of the PDU session for the LADN service area or the timer T358x associated with the S-NSSAI of the PDU session for the LADN service area or the timer T358x associated with the S-NSSAI of the PDU session for the LADN DNN based on at least one of the timer value, the S-NSSAI and DNN provided during the PDU session, or the request type, or it may control not to send a PDU session establishment request message or a PDU session modification request message.

[0158] According to the implementation method, the contents in [Table 11] can be defined to handle network denials caused by congestion control.

[0159] [Table 11]

[0160] According to the implementation method, PDU session-related messages can be defined as shown in [Table 12].

[0161] [Table 12]

[0162] As shown in [Table 12], based on whether the 5GSM rejection reason indicates insufficient resources for LADN S-NSSAI and LADN DNN within the LADN service area, the PDU session establishment rejection message, PDU session modification rejection message, and / or PDU session release command message may include at least one of the fallback timer value or retry indicator.

[0163] According to the implementation method, the reasons associated with specific network failures and congestion / authentication failures of PLMN or SNN can be defined as shown in [Table 13].

[0164] [Table 13]

[0165] Examples of the methods proposed above can also be included as one of the implementation methods of this disclosure; therefore, it is clear that they can be considered as types of proposed methods. Furthermore, the methods proposed above can be implemented independently, but can also be implemented as a combination (or merging) of some proposed methods. Rules can be defined such that the base station notifies the terminal via predefined signals (e.g., physical layer signals or higher layer signals) of information regarding whether to apply the proposed methods (or information about the rules governing the proposed methods).

[0166] This disclosure may be embodied in other specific forms without departing from the technical concept 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 this disclosure should be determined by a reasonable interpretation of the appended claims, and all variations within the equivalent scope of this disclosure are included within its scope. Furthermore, claims that are not explicitly referenced in the claims may be combined to form embodiments, or may be included as new claims by subsequent amendments.

[0167] Industrial applicability

[0168] The embodiments disclosed herein can be applied to a variety of wireless access systems. Examples of various wireless access systems include 3GPP or 3GPP2 systems.

[0169] The embodiments disclosed herein can be applied not only to the various wireless access systems described above, but also to all technical fields employing various wireless access systems. Furthermore, the proposed method can also be applied to millimeter-wave and THz communication systems using the ultra-high frequency band.

[0170] Furthermore, the embodiments disclosed herein can also be applied to various applications, such as autonomous vehicles and drones.

Claims

1. A method performed by a network in a wireless communication system, the method comprising the following steps: Activate congestion control functions; Receive request messages from wireless devices; as well as Send a message to the wireless device including a reason for rejecting the request message. The rejection reason indicates insufficient resources for LADN single network slice selection auxiliary information S-NSSAI and LADN data network name DNN within the local data network LADN service area.

2. The method according to claim 1, wherein, The message including the rejection reason also includes a fallback timer value, which prevents the request message from being retransmitted within a certain period of time.

3. The method according to claim 2, wherein, Since the request message is related to emergency services, the message including the reason for rejection does not include the fallback timer value.

4. The method according to claim 1, wherein, The congestion control function is a function used to control network congestion based on the LADN service area.

5. The method according to claim 1, wherein, The congestion control function is activated based on the resources of the LADN S-NSSAI and the LADN DNN within the LADN service area.

6. The method according to claim 1, wherein, The congestion control function is activated based on at least one of the following: the number of wireless devices connected to the LADN service area, the maximum number of wireless devices that can connect to the LADN service area, or the number of wireless devices requesting to connect to the LADN service area.

7. The method according to claim 1, wherein, The congestion control function is activated based on a request from at least one other network entity.

8. The method according to claim 1, wherein, The network includes at least one of Access and Mobility Management Function (AMF) or Session Management Function (SMF).

9. The method according to claim 8, wherein, Based on the receipt of the request message when the congestion control function is activated, the AMF does not forward the PDU session-related messages included in the request message to the SMF.

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

11. The method according to claim 1, wherein, The message including the reason for rejection includes at least one of the following: a DL NAS transmission message related to a PDU session, a PDU session modification rejection message, a PDU session establishment rejection message, or a PDU session release command message.

12. A method performed by a wireless device in a wireless communication system, the method comprising the steps of: Send a request message to the network; Receive from the network a message including a reason for rejection of the request message; as well as The retransmission of the request message is controlled based on whether the message, including the rejection reason, includes a backoff timer value. The rejection reason indicates insufficient resources for selecting auxiliary information S-NSSAI and LADN DNN for LADN single network slices within the local data network LADN service area.

13. The method according to claim 12, wherein, Controlling the retransmission of the request message includes: Based on the message including the rejection reason, including the backoff timer value, the retransmission of the request message is prevented for a time period corresponding to the backoff timer value; and The request message is retransmitted based on the message including the backoff timer value, which includes the reason for rejection.

14. A network device in a wireless communication system, the network device comprising: transceiver; as well as The processor is connected to the transceiver. The processor controls the process to: Activate congestion control functions; Receive request messages from wireless devices; and Send a message to the wireless device including a reason for rejection of the request message, and The rejection reason indicates insufficient resources for selecting auxiliary information S-NSSAI and LADN DNN for LADN single network slices within the local data network LADN service area.

15. A wireless device in a wireless communication system, the wireless device comprising: transceiver; as well as The processor is connected to the transceiver. The processor controls the process to: Send a request message to the network; Receive from the network a message including a reason for rejection of the request message; and Based on whether the message including the rejection reason includes a backoff timer value to control the retransmission of the request message, and The rejection reason indicates insufficient resources for selecting auxiliary information S-NSSAI and LADN DNN for LADN single network slices within the local data network LADN service area.

16. A communication device, the communication device comprising: At least one processor; as well as At least one computer memory, connected to the at least one processor and storing instructions that perform operations based on execution by the at least one processor, the operations including: Send a request message to the network; Receive from the network a message including a reason for rejection of the request message; and The retransmission of the request message is controlled based on whether the message, including the rejection reason, includes a backoff timer value. The rejection reason indicates insufficient resources for selecting auxiliary information S-NSSAI and LADN DNN for LADN single network slices within the local data network LADN service area.

17. A non-transitory computer-readable medium storing at least one instruction, in, The non-transitory computer-readable medium includes the at least one instruction executable by a processor. Wherein, the at least one instruction causes the device to: Send a request message to the network; Receive from the network a message including a reason for rejection of the request message; and Based on whether the message including the rejection reason includes a backoff timer value to control the retransmission of the request message, and The rejection reason indicates insufficient resources for selecting auxiliary information S-NSSAI and LADN DNN for LADN single network slices within the local data network LADN service area.

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